Infrared touch and hover system using time-sequential measurements

An apparatus comprising:

• a substantially planar light guide having a first edge, a second edge, a first side, and a second side, wherein:
• the first side and the second side are substantially planar and substantially parallel to one another,
• the first edge and the second edge are both substantially parallel to the first side and to the second side, and
• the first edge and the second edge are substantially orthogonal to one another;
• and
• the substantially planar light guide includes:
• a plurality of first light-turning arrangements distributed across a touch-sensitive region of the substantially planar light guide, each first light-turning arrangement configured to substantially redirect light that strikes the first light-turning arrangement from a direction that is parallel to the second edge such that the redirected light travels out of the light guide in a direction substantially normal to the first side, and
• a plurality of second light-turning arrangements distributed across the touch-sensitive region of the substantially planar light guide, each second light-turning arrangement configured to substantially redirect light that strikes the second light-turning arrangement from a direction substantially normal to the first side such that the redirected light travels in a direction parallel to the first edge.