Patent ID: 9541813
Date: 2017-01-10
CPC Classifications: G02F,G09G

Claim:
1. An image display device with a memory, comprising: a display unit which includes a first substrate, a second substrate, and an electrophoretic layer; the first substrate in which a plurality of pixels each having a switching element and a pixel electrode are arranged in matrix; the second substrate on which a counter electrode is formed; the electrophoretic layer formed by containing electrophoretic particles, which is interposed between the first substrate and the second substrate; and a voltage application unit which updates a display state of the display unit to a next screen in a prescribed color density by applying a voltage to the electrophoretic particles via the pixel electrode and the counter electrode in a screen update period, wherein the electrophoretic particles contain n kinds (n is an integer of 2 or larger) of charged particles C1 to Cn which are mutually different in colors and threshold voltage for starting electrophoresis; provided that for each m, a threshold voltage |Vth(Cm)| of the charged particles Cm satisfies a relation of |Vth(Cm)|<|Vth(C(m−1))|, where m are all the integers from 2 to n; and the voltage application unit applies a compensation voltage for suppressing movement of the charged particles Cn in a final period of the screen update period, wherein the compensation voltage is a voltage VE that is different from a reference potential, provided that an integral regarding a potential difference between the pixel electrode and the counter electrode with respect to time from a point at which apply of the voltage by the voltage application unit is ended until ∞ is defined as ∫ΔVdt=∫(Vpix−Vcom)dt, and an absolute value of the integral when a 0 voltage is applied in the final period and an absolute value of the integral when the voltage VE is applied in the final period are |∫ΔVdt (0)| and |∫ΔVdt (VE≠0)|, respectively, the voltage application unit applies the voltage VE satisfies a relation of |∫ΔVdt (0)|>|∫ΔVdt (VE≠0)|, and provided that a panel equivalent circuit time constant of the pixel electrode is τ, a panel equivalent circuit time constant of the counter electrode is a τ, and a feed-through voltage is Vfd, the voltage VE satisfies a relation of VE=(a−1)/a×Vfd.