Display mode controlling device, controlling method thereof and display device

A display device, comprising a display panel, a display mode controlling device, and a control module,

• wherein the display mode controlling device is configured to switch between a planar display mode and a virtual curved display mode of a display panel, the display mode controlling device comprises:
• a first substrate comprising a plurality of lens units arranged in an array, each of the plurality of lens units being provided with an annular diffractive phase grating;
• a second substrate aligned with the first substrate;
• a liquid crystal (LC) layer located between the first substrate and the second substrate;
• and
• a control electrode configured to generate a predetermined electric field to control a deflection state of a LC molecule,
• wherein the control module is configured to power on the display mode controlling device so as to allow the display panel to present the planar display mode, and to power off the display mode controlling device so as to allow the display panel to present the virtual curved display mode.

A display mode controlling device for switching between a planar display mode and a virtual curved display mode of a display panel, comprising:

• a first substrate comprising a plurality of lens units arranged in an array, each of the plurality of lens units being provided with an annular diffractive phase grating;
• a second substrate aligned with the first substrate;
• a liquid crystal (LC) layer located between the first substrate and the second substrate;
• and
• a control electrode configured to generate a predetermined electric field to control a deflection state of a LC molecule,
• wherein the annular diffractive phase grating comprises N steps in which adjacent steps have a phase difference of 2π/N, wherein N=2m, and m is a positive integer;
• and
• wherein each of the steps has a height
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• wherein λ is a wavelength of emergent light of the display panel, n is a refractivity of the first substrate, no is a minimum refractivity of the LC molecule with respect to the emergent light of the display panel, j is a number of Fresnel zone, d is a width of Fresnel zone, and i is a positive integer.