Electronic devices with optical sensor isolation

A wristwatch, comprising:

• a display;
• a housing in which the display is mounted, wherein the housing has a transparent portion that does not overlap the display;
• a band coupled to the housing;
• photodetectors;
• and
• coherent fiber bundle material between each of the photodetectors and the transparent portion, wherein the photodetectors detect light that passes through the coherent fiber bundle material and the transparent portion of the housing, wherein each of the photodetectors is configured to operate in a different respective visible-light wavelength band, and wherein the photodetectors are arranged in a ring.

An electronic device, comprising:

• a housing configured to separate an interior region from an exterior region;
• an image transport layer that is coupled to the housing and that has opposing first and second surfaces;
• and
• a two-dimensional infrared optical touch sensor having infrared photodetectors that detect infrared light passing through the image transport layer from the first surface to the second surface, wherein the two-dimensional infrared optical touch sensor is configured to receive touch input associated with an external object in the external region.