Fig. 4: Encoding and decoding process of the information encoder.

a Schematic diagram of pattern design for information encoding. Four active areas with different Poker patterns were predesigned on the upper substrate of a single LC cell by etching the corresponding patterned indium tin oxide (ITO) on one substrate (A1, A2, A3 and A4) while a planar ITO (A0) on the other substrate as a common electrode. These active areas can be independently driven by an applied electric signal (E). b The encoding table describing the one-to-one correspondence between the specific patterns and the characters. c The experimental patterns representing a series of words “ECUST˽1952!” were encrypted with binary codes. The scale bar is 5 mm. d The decryption rules of the characters (such as “U”, “S”, “E” and “1”) were formulated with 20 bits binary codes, where the first 4 bits represented four active areas from the left to right, the driven area denoted “1” and the non-driven area was “0”. The frequency of driven signal was expressed by the middle 8 bits, in which the former and latter 4 bits represented the ten digits and single digits of the frequency respectively. In addition, the final 8 bits denoted the field strength of driven signal, in which the deciles and percentiles were the former and latter 4 bits. “˽” means the “space” character.