Reflective display comprising a lightguide and light turning film creating multiple illumination peaks

A display comprising:

• a reflective spatial light modulator diffusely reflecting incident light;
• a lightguide comprising a core layer having opposing surfaces with a thickness not greater than 0.5 millimeters therebetween, a lightguide region and a light emitting region;
• a light source positioned to emit light that propagates by total internal reflection within the lightguide region to the light emitting region;
• a cladding layer having a first side optically coupled to the core layer and a second side opposite the first side;
• a plurality of light extraction features arranged within the light emitting region in a pattern that varies spatially in the light emitting region, the plurality of light extraction features frustrate totally internally reflected light from the light source propagating between the opposing surfaces of the core layer such that light exits the core layer in the light emitting region into the cladding layer;
• and
• a light turning film optically coupled to the second side of the cladding layer, the light turning film having a thickness in a thickness direction and comprising a plurality of light turning features that redirect frustrated totally internally reflected light from the core layer into a first portion of light and a second portion of light,
• wherein the first portion of light exits the light turning film toward the reflective spatial light modulator with a first peak luminous intensity at a first angle from the thickness direction of the light turning film, the second portion of light exits the light turning film toward the reflective spatial light modulator with a second peak luminous intensity at a second angle from the thickness direction of the light turning film on an opposite side of the thickness direction of the light turning film than the first angle, and the light diffusely reflecting from the reflective spatial light modulator due to the first portion of light and the second portion of light of the frustrated totally internally reflected light has a peak luminous intensity within 10 degrees from a direction normal to a light emitting surface of the display.

A display comprising:

• a reflective spatial light modulator diffusely reflecting incident light;
• a lightguide comprising a core layer having opposing surfaces with a thickness not greater than 0.5 millimeters therebetween, a lightguide region and a light emitting region;
• a light source positioned to emit light that propagates by total internal reflection within the lightguide region to the light emitting region;
• a cladding layer having a first side optically coupled to the core layer and a second side opposite the first side;
• a plurality of light extraction features arranged within the light emitting region in a pattern that varies spatially in the light emitting region, the plurality of light extraction features frustrate totally internally reflected light from the light source propagating between the opposing surfaces of the core layer such that light exits the core layer in the light emitting region into the cladding layer;
• and
• a light turning film optically coupled to the second side of the cladding layer, the light turning film having a thickness in a thickness direction and comprising a plurality of light turning features that redirect frustrated totally internally reflected light from the core layer into a first portion of light and a second portion of light,
• wherein the first portion of light exits the light turning film toward the reflective spatial light modulator with a first peak luminous intensity at a first angle between 5 and 20 degrees from the thickness direction of the light turning film measured in air, the second portion of light exits the light turning film toward the reflective spatial light modulator with a second peak luminous intensity at a second angle larger than the first angle between 15 and 35 degrees measured in air from the thickness direction of the light turning film on a same side of the thickness direction of the light turning film than the first angle, and the light diffusely reflecting from the reflective spatial light modulator due to the first portion of light and the second portion of light of the totally internally reflected light frustrated and exited the core layer has a peak luminous intensity within 10 degrees measured in air from a direction normal to a light emitting surface of the display.