Patent ID: 9304627
Filing Date: 2016-04-05
CPC Classification: G02B,G06F

Claim Text:
1. A display device comprising: a display panel having a display area on which an image is displayed; a backlight unit including a surface light source section arranged at a back surface side of the display panel and a diffuse reflection sheet arranged at a back surface side of the surface light source section; and a plurality of position information patterns arranged on the display area and each representing information regarding a position thereof on the display area, wherein the surface light source section includes: a transmittance of light transmitted from a front surface of the prism sheet to a back surface of the prism sheet is lowest when an incident angle thereof with respect to a sheet surface of the prism sheet is a determined angle of larger than 40° and smaller than 60°, the angle distribution conversion sheet has a conversion region that causes light incident on a front surface thereof at the determined angle as an incident angle with respect to a sheet surface of the angle distribution conversion sheet to be emitted from a back surface thereof at an emission angle of not larger than 40° or not smaller than 60° with respect to the sheet surface, in a cross-sectional view in a first direction perpendicular to an extension direction of prisms of the prism sheet, and when light for reading the position information pattern is applied to the front surface of the angle distribution conversion sheet at the determined angle as an incident angle with respect to the sheet surface of the angle distribution conversion sheet and in the first direction in a front view of the angle distribution conversion sheet, 20% or more of the light passes through the conversion region.