In association with the transition to terrestrial digital broadcasting in recent years, display devices capable of displaying a super high definition image are being developed. For preventing the image quality of the super high definition display devices from being impaired, the surface of the display device is demanded to have a capability of preventing outside light from being reflected.
Major examples of the measure for preventing outside light from being reflected include an antiglare treatment for reducing specularly reflected light with surface unevenness, and an antireflection treatment for reducing the reflectance through an interference effect of a multilayer thin film. In recent years, the antireflection treatment, which is easy to provide a high-quality image, is being brought into the mainstream.
The reflectance can be reduced more by increasing the number of layers of the multilayer thin film, but most products have a two-layer or three layer structure in view of the cost-benefit performance. Examples of the antireflection film of this type include one described in JP-A-2010-152311.
In recent years, even an antireflection film having a two-layer or three-layer is demanded to have an ultra low reflectance of 0.5% or less for preventing the image quality of the super high definition display device from being impaired.
However, although the antireflection film having an ultra low reflectance shows good visibility in the evaluation of antireflection capability performed commonly, in which the back surface of the film is blackened, the antireflection film may suffer whitening in some cases where the antireflection film is installed in a super high definition display device. The whitening cannot be detected as a haze, which is a common evaluation factor in the field of optical films. In other words, the whitening is low in the whiteness level and is such whiteness that is difficult to be recognized by the human under normal use environments. However, the whiteness may be recognized through careful observation in the case where the antireflection film having an ultra low reflectance is installed in a super high definition display device.
USPTO Backgrounds
USPTO Backgrounds