Patent ID: 8164814
Filing Date: 2012-04-24
Classification: E06B

Abstract:
1. A domestic viewing panel unit for a door, comprising: a first panel comprising one or more first panel light transparent regions that are substantially transparent to visible light and one or more first panel light hindering regions which substantially hinder transmission of visible light; a second panel comprising one or more second panel light transparent regions that are substantially transparent to visible light and one or more second panel light hindering regions which substantially hinder transmission of visible light; an actuator for moving said second panel relative to said first panel in a plane parallel to the plane of said first panel; wherein said first and second panels are arranged such that the amount of visible light transmitted unhindered through the domestic viewing panel unit is a non-linear function of the position of the second panel relative to the position of the first panel, for at least a portion of an allowed range of actuation.