Abstract: A rear illuminated light guide for an LCD screen with in-coupling gratings to receive backlight from an input surface and to spread received backlight laterally within the light guide. Out-coupling gratings receive laterally spread backlight and output at least some of the received laterally spread backlight through an output surface that is opposite to the input surface and towards the LCD screen. The input and output gratings have lateral offset.

Abstract: A light guide assembly (2) for use in a touch sensitive area (3) of an optical touch sensing device (1) for touch screens is configured to receive light, to allow the light thereby received to propagate in the light guide assembly, and to deliver the light thereby propagated in the light guide assembly further out of the light guide assembly. The light guide assembly comprises a plurality of light guide stripes (4, 5) for controlling the propagation of light. The optical touch sensing device is configured to detect the presence of an external object (10) on the basis of changes in the light delivered further out of the light guide assembly due to interaction of the light with the external object.

Abstract: A rear illuminated light guide for an LCD screen with in-coupling gratings to receive backlight from an input surface and to spread received backlight laterally within the light guide. Out-coupling gratings receive laterally spread backlight and output at least some of the received laterally spread backlight through an output surface that is opposite to the input surface and towards the LCD screen. The input and output gratings have lateral offset.