Patent ID: 8952884
Filing Date: 2015-02-10
Classification: G02F

Abstract:
1. A suspended particle device comprising: a first substrate; a first electrode arranged on a surface of the first substrate; a second substrate; a second electrode arranged on a surface of the second substrate; and a suspension arranged between the first substrate and the second substrate, wherein the suspension includes particles and a disperse medium, the particles having anisotropy in their shape, wherein the particles are dispersed in the disperse medium and have a property that a direction of a long axis of the particles is aligned with a direction of an electric field, the suspended particle device being configured to be connected to a drive unit including an alternate current voltage source so that an orientation of the particles is controlled by an alternate-current voltage to be applied between the first electrode and the second electrode by the alternate current voltage source, and wherein the drive unit controls so that the alternate-current voltage is a first alternate-current voltage to change the orientation of the particles from a random orientation state to an orientation state along an electric field direction of the first alternate-current voltage in a startup period, is a second alternate-current voltage to maintain the orientation of the particles of the startup period in a sustaining period, and is an equipotential to change the orientation of the particles from the orientation state along the electric field direction to the random orientation state in a shutdown period, wherein “a” is greater than “b” where “a” represents a frequency of the alternate-current voltage in a the sustaining period; and “b” represents a frequency of the alternate-current voltage in the shutdown period, wherein said suspended particle device is configured to receive one or more steps of constant voltages, or a ramp wave of voltage from said drive unit in a period of changing the frequency of the alternate-current voltage from “a” to “b” so as to shorten a reduction time of a transmittance in the shutdown period, and wherein the drive unit controls so that the alternate-current voltage is a third alternate-current voltage before changing the alternate-current voltage to the equipotential in the shutdown period after a completion of the sustaining period, an absolute value of the second alternate-current voltage being greater than an absolute value of the third alternate-current voltage.