Linear optical cavity array light guide
AssigneeThe University of British Columbia
InventorLorne A. Whitehead
Life of this patent
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Abstract
Light reflective films have example application in hollow light guides and luminaires. The films comprise parallel channels distributed in layers or otherwise at different depths in the films. The channels provide interfaces at which light is reflected or redirected. The channels have a sufficient density that the film reflects a large proportion of light incident on a first face of the film. The channels may be filled with a gas such as air, a vacuum or a polymer for example. Methods for making films can include stacking thin sheets patterned with grooves, casting or extrusion.
Claims20
A light reflecting film comprising:
- a thin layer of a first material having a thickness and a first index of refraction wherein formed within the layer are channels extending parallel to one another in a longitudinal direction, the channels comprising a second material having a second index of refraction less than the first index of refraction,
- the channels arranged at a plurality of different depths relative to a front face of the light reflecting film,
- the channels having a cross sectional shape that provides interfaces at which light incident from the front face of the light reflecting film is refracted or reflected.
A light reflecting film comprising:
- a layer of a first material having a thickness and a first index of refraction;
- wherein formed within the layer are channels extending parallel to one another in a longitudinal direction, the channels comprising a second material having a second index of refraction less than the first index of refraction,
- the light reflecting film having an active area within which the film reflects at least 90% of light that is incident on a front face of the light reflecting film at an angle of 45 degrees or more to a direction normal to the light reflecting film;
- and
- the channels are arranged at a plurality of different depths relative to the front face of the light reflecting film and distributed in the light reflecting film such that at least within the active area substantially all straight lines in a transverse cross section plane of the light reflecting film that originate from any point P on the front face of the light reflecting film and enter the light reflecting film with an angle in the range of ±Φ of a plane that is parallel to the channels and is perpendicular to the front face of the light reflecting film cross at least one of the channels before reaching a rear face of the light reflecting film where Φ is 60 degrees.
A method for making a light reflective film, the method comprising:
- assembling a stack of light transmissive sheets, wherein a plurality of the light transmissive sheets have a first face patterned with spaced apart parallel grooves and the light transmissive sheets are oriented so that the grooves in different ones of the light transmissive sheets are parallel;
- and
- affixing the plurality of light transmissive sheets together to define a plurality of channels, each channel defined between one of the grooves and a second face of an adjacent one of the plurality of light transmissive sheets
- the channels arranged at a plurality of different depths relative to a front face of the light reflecting film,
- the channels having a cross sectional shape that provides interfaces at which light incident from the front face of the light reflecting film is refracted or reflected.
Dependencies are inferred from the claim text.