Patent ID: 6669356
Filing Date: 2003-12-30
Classification: G02B,G02F

Abstract:
A diffuser sheet in combination with an illumination device, the diffuser sheet having four major elongated edges which define the major sides of the sheet, the combination comprising:the diffuser sheet being provided inside the illumination device and fitted to a main body of the illumination device by being sandwiched, at least at a portion of the sheet and in a direction of thickness of the sheet, between the main body and a frame fitted to the main body, the diffuser sheet being located at an elevation different than an elevation(s) of a light source and a light guide into which the light source directs light so that the diffuser sheet receives light from the light guide and is at least partially located between the light guide and a device to be illuminated, the diffuser sheet being located closer to the device to be illuminated than the light source and light guide; wherein the sheet has a cut formed at least in a corner thereof within a region sandwiched in a direction of thickness of the sheet between the main body and the frame so that the cut does not extend beyond a frame opening line (FL) defined by a rim of an opening in said frame, wherein said cut is provided in order to prevent or reduce bending of the sheet upon change in temperature; wherein a point of intersection is defined by an intersection of: (a) a first line along a first major elongated edge of the sheet adjacent said corner, and (b) a second line along a second major elongated edge of the sheet adjacent the corner; wherein said point of intersection is not embedded within said main body and is not embedded within said frame so that the sheet and illumination device are sized so that the sheet would fit in the illumination device regardless of whether or not the cut was provided therein.