Ultra-thin frontlight having an optical coupling element
AssigneereMarkable AS
InventorsThomas James Watson, Emma Rachel Lewis, Isobel Jane Ashbey, Hessel Vink
Life of this patent
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Abstract
Embodiments of the invention provide an ultra-thin frontlight comprising an optical coupling element that receives light from a light source and directs the received light into a lightguide which is thinner than the height of the light source. The height of the optical coupling element is approximately the same or greater than that of the light source and the optical coupling element is refractively index matched to the lightguide. The optical coupling element may be composed of the same material as the lightguide. The optical coupling element has several reflecting surfaces, which may be polished, metallized, or have dielectric mirror coatings.
Claims20
A frontlight in a tablet computing device, comprising:
- a light source;
- an optical coupling element that receives light from the light source wherein the optical coupling element comprises at least two mirror coated surfaces and at least two uncoated optically polished surfaces;
- and
- a lightguide that receives light from the light source through the optical coupling element,
- wherein the light source has an emitter height greater than a thickness of the lightguide.
A frontlight in a tablet computing device, comprising;
- a light source;
- an optical coupling element that receives light from the light source, wherein the optical coupling element has a height equal to or greater than the height of the light source and wherein the optical coupling element has a top surface and a bottom surface, wherein both the top surface and the bottom surface are optically polished, wherein light having an incident angle below a critical angle for total internal reflection that is incident on at least one of the top surface and the bottom surface is reflected into the body of the optical coupling element;
- and
- a lightguide that receives light from the light source through the optical coupling element, wherein the light source has an emitter height greater than a thickness of the lightguide,
- wherein the optical coupling element has a front surface adjacent to the lightguide that has been mirror coated, wherein light incident on the front surface from within the optical coupling element is reflected back into the optical coupling element, and a rear surface adjoining the light source that has been mirror coated, wherein light incident on the rear surface from within the optical coupling element is reflected back into the optical coupling element.
Dependencies are inferred from the claim text.