Display apparatus and method of operating display apparatus

A method for operating a display apparatus, wherein the display apparatus comprises:

• an array substrate;
• a counter substrate facing the array substrate;
• a liquid crystal layer between the array substrate and the counter substrate;
• at least one optical compensation film between the array substrate and the counter substrate, extending throughout a display area of the display apparatus;
• a control electrode between the array substrate and the counter substrate, extending throughout the display area of the display apparatus;
• and
• a back light configured to provide light for image display;
• wherein the liquid crystal layer in a dark state has a first phase retardation, which is a product of a refractive index of the liquid crystal layer and a cell gap corresponding to a thickness of the liquid crystal layer along a direction from the array substrate to the counter substrate;
• wherein the method comprises:
• when the liquid crystal layer is in the dark state, applying a first voltage to the control electrode to control the at least one optical compensation film to give a second phase retardation, such that a sum of the first phase retardation and the second phase retardation is substantially same as an integral multiple of a wavelength of light emitted from the back light, thereby reducing dark state light leakage of the display apparatus;
• and
• when the display apparatus is in an image display mode, applying a second voltage to the control electrode to control the at least one optical compensation film to reduce a contrast ratio and transmittance of the display apparatus in the image display mode, thereby achieving a reduced viewing angle.

A method for fabricating a display apparatus, comprising:

• forming an array substrate;
• forming a counter substrate;
• assembling the array substrate and the counter substrate into a cell;
• forming a liquid crystal layer in the cell between the array substrate and the counter substrate;
• forming at least one optical compensation film, the at least one optical compensation film formed between the array substrate and the counter substrate, extending throughout a display area of the display apparatus;
• forming a control electrode, the control electrode formed between the array substrate and the counter substrate, and extending throughout the display area of the display apparatus;
• and
• forming a back light configured to provide light for image display;
• wherein the liquid crystal layer in a dark state has a first phase retardation, which is a product of a refractive index of the liquid crystal layer and a cell gap corresponding to a thickness of the liquid crystal layer along a direction from the array substrate to the counter substrate;
• under control of the control electrode, the at least one optical compensation film gives a second phase retardation when the liquid crystal layer is in the dark state;
• and
• a sum of the first phase retardation and the second phase retardation is substantially same as an integral multiple of a wavelength of light emitted from the back light, thereby reducing dark state light leakage of the display apparatus;
• wherein, under control of the control electrode, the at least one optical compensation film is configured to reduce a contrast ratio and transmittance of the display apparatus in an image display mode, thereby achieving a reduced viewing angle.