Liquid crystal display element

A liquid crystal display device comprising:

• at most two liquid crystal panels;
• a first liquid crystal panel and a second liquid crystal panel exhibiting at least two stable states of a planar state and a focal conic state with no voltage applied;
• the first liquid crystal panel and the second liquid crystal panel each comprising a liquid crystal with a memory effect,
• the liquid crystals having selective reflection wavelengths in the planar state appearing in a visible range,
• the first liquid crystal panel and the second liquid crystal panel having different selective reflection wavelengths;
• the first liquid crystal panel and the second liquid crystal panel being combined to be respectively provided on a viewer side and on a no-viewer side;
• wherein the first liquid crystal panel has a shorter selective reflection wavelength than the second liquid crystal panel;
• and
• a color layer provided between the liquid crystal of the first liquid crystal panel and the liquid crystal of the second liquid crystal panel,
• wherein the color layer has a transmission property that is set such that the transmissivity at a wavelength shorter than the selective reflection wavelength of the second liquid crystal panel by 70 nm is not higher than 85% of the transmissivity at a wavelength shorter than the selective reflection wavelength of the second crystal panel by 30 nm,
• whereby at least a white display can be provided.

A method for preparing a liquid crystal display device, comprising:

• liquid crystals with a memory effect, the liquid crystals exhibiting at least two stable states of a selective reflection state and a transmissive state with no voltage applied;
• and
• at most two liquid crystal panels;
• a first liquid crystal panel and a second liquid crystal panel provided in layers, the first liquid crystal panel and the second liquid crystal panel having different selective reflection wavelengths;
• and
• the method comprising:
• providing a color layer on the rear side;
• controlling the selective reflection wavelengths of the respective liquid crystal panels so that the midpoint between coordinates corresponding to two developed colors produced under a standard light source lies at a position apart from the white point by a distance of not greater than 0.03 on C.I.E. xy chromaticity coordinates
• wherein the two developed colors are indicated on the xy chromaticity coordinates with one of the liquid crystal panels being in the selective reflection state, and the other being in the transmissive state;
• and
• providing white by mixing at least the two developed colors and a color (except white) developed by the color layer.