Optic having a dichroic reflector

A system comprising a touch-sensitive display configured to detect touch by capturing an image of one or more objects disposed on a touch-sensitive display surface, the system comprising:

• an infrared illuminant configured to illuminate the one or more objects from behind the touch-sensitive display surface with light having a median wavelength;
• a detector configured to capture the image;
• and
• an optic configured to deliver to the detector light reflected from the one or more objects, the optic comprising:
• a wedge-shaped light guide having opposing first and second faces;
• and
• a turning film bonded to the wedge-shaped light guide, the turning film comprising a plurality of facets oblique to the first face of the wedge-shaped light guide and supporting a dichroic coating.

A system comprising a touch-sensitive display configured to detect touch by capturing an image of one or more objects disposed on a touch-sensitive display surface while displaying a visible image on the touch-sensitive display surface, the system comprising:

• an infrared illuminant configured to illuminate the one or more objects from behind the touch-sensitive display surface with light having a median wavelength;
• a detector configured to capture the image;
• an optic configured to focus on the detector light reflected from the one or more objects and to attenuate a reflection of the light, the optic comprising:
• a wedge-shaped light guide having opposing first and second faces and comprising a material having a first refractive index, the first face supporting a cladding layer having a second refractive index less than the first refractive index, a thickness of the cladding layer an odd-integer multiple of one-half of the median wavelength;
• and
• a turning film bonded to the cladding layer via an interface layer, the interface layer having a third refractive index matched to the first refractive index, the turning film comprising a plurality of facets oblique to the first face of the wedge-shaped light guide and supporting a dichroic coating;
• an image-creating subsystem adapted to create the visible image, and comprising a visible illuminant configured to project visible light through the optic in a direction toward the touch-sensitive display surface and substantially normal to the opposing first and second faces.