US 12,248,226 B2
Driving methods for a variable light transmission device
Kosta Ladavac, Somerville, MA (US); Richard J. Paolini, Jr., Framingham, MA (US); Stephen J. Telfer, Arlington, MA (US); Lee Yezek, Watertown, MA (US); Sunil Krishna Sainis, Melrose, MA (US); and Peter Carsten Bailey Widger, Nashua, NH (US)
Assigned to E Ink Corporation, Billerica, MA (US)
Filed by E INK CORPORATION, Billerica, MA (US)
Filed on Jan. 17, 2023, as Appl. No. 18/097,819.
Application 18/097,819 is a continuation of application No. 16/862,910, filed on Apr. 30, 2020, granted, now 11,579,510.
Claims priority of provisional application 62/844,205, filed on May 7, 2019.
Prior Publication US 2023/0152659 A1, May 18, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G02F 1/1685 (2019.01); G02F 1/167 (2019.01); G02F 1/1676 (2019.01)
CPC G02F 1/1685 (2019.01) [G02F 1/167 (2013.01); G02F 1/1676 (2019.01)] 12 Claims
OG exemplary drawing
 
1. A method of operating a variable light transmission device, the method comprising:
providing the variable light transmission device comprising an electrophoretic medium layer comprising a plurality of discrete droplets, each droplet of the electrophoretic medium comprising charged particles in a suspending fluid, each droplet being present within a capsule or within a microcell, each droplet being surrounded by walls, the walls including lateral walls, wherein the electrophoretic medium layer is disposed between two electrodes;
applying an electric field across the electrophoretic medium layer via application of a first driving waveform that causes movement of the charged particles to the lateral walls of the droplets, resulting in aggregation of the charged particles to the lateral walls of the droplets, the variable light transmission device switching from an initial optical state to a final optical state, wherein the first driving waveform is applied from a start until a completion of the application of the first driving waveform, wherein the time from the start until the completion of the application of the first driving waveform is a total driving time of the first driving waveform, wherein the final optical state has higher percent light transmission than the initial optical state, wherein the first driving waveform is a superposition of a carrier waveform and a modulator waveform, wherein the carrier waveform has amplitude V1 and frequency ω1, wherein the V1 is from about 50 V to about 150 V, wherein ω1 is from about 50 Hz to about 1000 Hz, wherein the modulator waveform has initial amplitude V2 and frequency ω2, wherein V2 is from about 5 V to about 50 V, wherein ω2 is form about 0.1 Hz to about 10 Hz, wherein V1 is greater than V2 and ω1 is greater than ω2, wherein the amplitude of the modulator waveform is variable and is reduced from an initial amplitude value at the start of the application of the first driving waveform to the variable light transmission device to a final amplitude value at the completion of the application of the first driving waveform to the variable light transmission device, wherein the reduction of the amplitude value of the modulator waveform from the initial amplitude value to the final amplitude value is performed in 5 or more sequential steps, the amplitude value of the modulator waveform at any one step of the 5 or more sequential steps being less than the amplitude value of the modulator waveform at all steps that took place prior to said step during the application of the first driving waveform, and wherein the % Total Transmittance of the final optical state of the variable light transmission device is from about 30% to about 95%.