Liquid-crystal display device

Abstract

Provided is a liquid-crystal display device having a high contrast ratio over a wide viewing angle range and having little coloration occurring when black is displayed. The liquid-crystal display device has, in this order, a polarizer, a first [lambda] / 4 plate satisfying the condition nx > ny >= nz, a vertically oriented liquid-crystal cell, a second [lambda] / 4 plate having a substantially same Nz coefficient as the first [lambda] / 4 plate and satisfying the condition nx > ny >= nz, a double refraction layer satisfying the condition nx < ny <= nz, and another polarizer. The liquid-crystal cell has a liquid-crystal layer and blue, green, and red CF layers and satisfies at least one of the following equations. R(B) / R(G) > [delta]n(B) / [delta]n(G) R(R) / R(G) < [delta]n(R) / [delta]n(G) In the equation, R(B), R(G), and R(R) indicate retardations in the thickness direction of the liquid-crystal cell at wavelengths of 450nm, 550 nm, and 650 nm, respectively, and [delta]n(B), [delta]n(G), and [delta]n(R) indicate the double refractions of a liquid-crystal material of the liquid-crystal layer at wavelengths of 450nm, 550 nm, and 650 nm, respectively.

Description

technical field [0001] The present invention relates to a liquid crystal display device. More specifically, it relates to a VA (vertical alignment) mode liquid crystal display device using a circular polarizing plate. Background technique [0002] Liquid crystal display devices are widely used as display devices of various information processing devices typified by computers and television receivers. In particular, TFT-type liquid crystal display devices (hereinafter also referred to as "TFT-LCD") are expected to spread widely and further expand the market, and along with this, further improvement in image quality is desired. Hereinafter, TFT-LCD is taken as an example for description, but the present invention is not limited to TFT-LCD, and is applicable to common liquid crystal display devices, for example, liquid crystal display devices of simple matrix method and plasma addressing method. [0003] So far, the most widely used method in TFT-LCD is the so-called TN (twis...

AI Technical Summary

Problems solved by technology

If this useless reflection is not prevented, even if the display device realizes a substantially completely black display in a dark room environment, when viewed in a bright room environment, the amount of light at the time of black display of the display device increases, resulting in a decrease in contrast.

[0009] As mentioned above, in the circularly polarized light VA mode using a circular polarizing plate, although the transmittance improvement effect and the unnecessary reflection prevention effect can be obtained, in the conventional circularly polarized light VA mode liquid crystal display device, the There is still room for improvement in that the contrast ratio is low and sufficient viewing angle characteristics cannot be obtained.

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