CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0040832, filed on Apr. 8, 2019 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Aspects of embodiments of the present invention relate to a polarizing plate and an optical display apparatus including the same.

2. Description of the Related Art

A liquid crystal display is operated to emit light through a liquid crystal panel after receiving the light from a backlight unit. Since light from the backlight unit is incident at a right angle to a screen of the liquid crystal display, side contrast (CR) of the screen of the liquid crystal display is lower than front contrast of the screen, causing occurrence of color shift. In order to solve such a problem, an optical film including a pattern layer having a fine pattern structure may be used in a viewer-side polarizing plate of the liquid crystal display.

However, such a pattern structure can cause appearance of Moiré patterns on an optical display apparatus. Further, since the pattern structure is used in a viewer-side polarizing plate of the optical display apparatus, Moiré patterns become more prominent. In order to solve this problem, a film having the pattern structure may be disposed to be tilted at a certain angle (e.g., a predetermined angle) with respect to pixels in a liquid crystal panel to reduce appearance of Moiré patterns. However, tilting the film having the pattern structure with respect to the pixels of the panel is hardly effective in reducing appearance of Moiré patterns when applied to a large-area optical display apparatus. Therefore, there is a need for a polarizing plate which includes an optical film capable of providing reduction in color shift and improvement in contrast while preventing or substantially preventing appearance of Moiré patterns even when used in a large-area optical display apparatus.

The background technique of the present invention is disclosed in Japanese Unexamined Patent Publication No. 2006-251659.

SUMMARY

According to aspects of embodiments of the present invention, a polarizing plate which can provide improvement in contrast and reduction in side color shift while preventing or substantially preventing appearance of Moiré patterns, and an optical display apparatus including the same, are provided.

According to one aspect of embodiments of the present invention, a polarizing plate which can prevent or substantially prevent appearance of Moiré patterns when used in a large-area optical display apparatus is provided.

According to another aspect of embodiments of the present invention, a polarizing plate which can reduce side color shift is provided.

According to another aspect of embodiments of the present invention, a polarizing plate which can improve front contrast and side contrast is provided.

According to one or more embodiments of the present invention, a polarizing plate includes: a polarizer; and a pattern layer formed on a surface of the polarizer and including a first resin layer and a second resin layer facing the first resin layer, the first resin layer including a patterned portion located at at least a portion thereof facing the second resin layer, wherein the patterned portion includes at least two embossed optical patterns and a flat section between a pair of adjacent embossed optical patterns of the embossed optical patterns, each of the embossed optical patterns includes an upper surface defining a wave pattern, and the wave pattern has a value of about 20% to 60%, as calculated according to the following Formula 1:
(|H1−H2|/H1)×100,
where H1 denotes a maximum height (unit: μm) of the embossed optical pattern, as measured within the wave pattern, and H2 denotes a minimum height (unit: μm) of the embossed optical pattern, as measured within the wave pattern, and the wave pattern has a pitch of greater than about 100 μm and less than about 400 μm.

In one or more embodiments, the wave pattern may include a curved surface defined by a continuous succession of a convex surface and a concave surface, wherein an uppermost point of a convex surface of a first embossed optical pattern may be located between uppermost points of a pair of respective adjacent convex surfaces of a second embossed optical pattern adjacent to the first embossed optical pattern.

In one or more embodiments, the convex surface may have a maximum length equal to or different from a maximum length of the concave surface.

In one or more embodiments, the wave pattern may include a curved surface defined by a continuous succession of a convex surface and a concave surface, wherein the convex surface may have a maximum width H3 greater than a maximum width H4 of the concave surface, and H3-H4 may have a value of greater than 0.1 μm and less than or equal to 1 μm.

In one or more embodiments, the embossed optical pattern may satisfy the following Formula 2:
1<P/W≤10,
where P denotes a pitch (unit: μm) of the patterned portion, and W denotes a maximum width (unit: μm) of the optical pattern, and the embossed optical pattern may have a base angle θ of greater than or equal to about 75° and less than about 90°.

In one or more embodiments, the embossed optical pattern may have a trapezoidal, rectangular, or square cross-section.

In one or more embodiments, the second resin layer may directly adjoin the embossed optical patterns and the flat section.

In one or more embodiments, the first resin layer may have a different index of refraction than the second resin layer.

In one or more embodiments, the first resin layer may have a smaller index of refraction than the second resin layer.

In one or more embodiments, a longitudinal direction of the embossed optical pattern may be at an angle of about −5° to about +5° with respect to an absorption axis direction of the polarizer.

In one or more embodiments, the polarizing plate may further include: a protective layer formed on a surface of the pattern layer.

According to one or more embodiments, an optical display apparatus may include the polarizing plate according to any of the above-described embodiments.

According to an aspect of embodiments of the present invention, a polarizing plate may prevent or substantially prevent appearance of Moiré patterns when used in a large-area optical display apparatus.

According to another aspect of embodiments of the present invention, a polarizing plate may have reduced side color shift.

According to another aspect of embodiments of the present invention, a polarizing plate may have improved front contrast and side contrast.

