Switchable backlight unit
First Claim
1. A backlight unit comprising:
- a light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide;
a plurality of light sources configured to inject light into the light guide at the first light interface, each light source of the plurality of light sources being configured to selectively emit light having at least one of an intensity profile having a narrower distribution relative to an optical axis of the backlight unit, and an intensity profile having a wider distribution relative to the optical axis; and
an angle dependent diffuser layer comprising a first graded index film and a second graded index film, each of the first graded index film and the second graded index film configured to receive light from the second light interface of the light guide, the first graded index film being configured to homogenize received light that is incident on the graded index film from within a first range of acceptance angles corresponding to the intensity profile having a narrow distribution, and not homogenize light incident on the graded index film from outside of the first range of acceptance angles, and direct the received light that is homogenized by the first graded index film toward a first eye box, andthe second graded index film being configured to homogenize received light that is incident on the graded index film from within a second range of acceptance angles corresponding to intensity profile having a wide distribution, and not homogenize light incident on the graded index film from outside of the second range of acceptance angles, and direct the light that is homogenized by the second graded index film toward a second eye box.
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Accused Products
Abstract
Embodiments for a backlight unit are provided. In one example, a backlight unit comprises a light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide, and a plurality of light sources configured to inject light into the light guide at the first light interface. The example backlight unit also comprises a graded index film configured to receive light from the second light interface of the light guide, homogenize received light that is incident on the graded index film from within a range of acceptance angles and not homogenize light incident on the graded index film from outside of the range of acceptance angles, and direct the homogenized light toward an eye box.
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Citations
20 Claims
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1. A backlight unit comprising:
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a light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide; a plurality of light sources configured to inject light into the light guide at the first light interface, each light source of the plurality of light sources being configured to selectively emit light having at least one of an intensity profile having a narrower distribution relative to an optical axis of the backlight unit, and an intensity profile having a wider distribution relative to the optical axis; and an angle dependent diffuser layer comprising a first graded index film and a second graded index film, each of the first graded index film and the second graded index film configured to receive light from the second light interface of the light guide, the first graded index film being configured to homogenize received light that is incident on the graded index film from within a first range of acceptance angles corresponding to the intensity profile having a narrow distribution, and not homogenize light incident on the graded index film from outside of the first range of acceptance angles, and direct the received light that is homogenized by the first graded index film toward a first eye box, and the second graded index film being configured to homogenize received light that is incident on the graded index film from within a second range of acceptance angles corresponding to intensity profile having a wide distribution, and not homogenize light incident on the graded index film from outside of the second range of acceptance angles, and direct the light that is homogenized by the second graded index film toward a second eye box. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A backlight unit for a display device, the backlight unit comprising:
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a wedge shaped light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide; a plurality of light sources configured to inject light into the light guide at the first light interface, the plurality of light sources being configured to selectively emit light having a first intensity profile having a narrower distribution relative to an optical axis of the backlight unit, and light having a second intensity profile having a wider distribution relative to the optical axis; a first graded index film configured to receive light from the light guide, homogenize and diffuse light having a first angular acceptance range corresponding to the first intensity profile, and not homogenize and diffuse light having an acceptance range outside of the first angular acceptance range, and direct the homogenized and diffused light toward a first eye box at a first location; and a second graded index film configured to receive light from the light guide, homogenize and diffuse light having a second angular acceptance range corresponding to the second intensity profile, and not homogenize and diffuse light having an acceptance range outside of the second angular acceptance range, and direct the homogenized and diffused light toward a second eye box at a second location. - View Dependent Claims (10, 11, 12, 13)
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14. A display device comprising:
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a display panel; and a backlight unit configured to illuminate the display panel, the backlight unit comprising a wedge shaped light guide configured to receive light at a first light interface located at an end of the light guide and output light via a second light interface located at a face of the light guide, a plurality of light sources configured to inject light into the light guide at the first light interface, the plurality of light sources being configured to selectively emit light having a first intensity profile having a narrower distribution relative to an optical axis of the backlight unit during a narrow viewing mode, and light having a second intensity profile having a wider distribution relative to the optical axis during a wide viewing mode, and a first graded index layer configured to receive light from the light guide, homogenize and diffuse light having a first angular acceptance range corresponding to the first intensity profile, and not homogenize and diffuse light having an acceptance range outside of the first angular acceptance range, and direct the homogenized and diffused light toward a first eye box at a first location, and a second graded index layer configured to receive light from the light guide, homogenize and diffuse light having a second angular acceptance range corresponding to the second intensity profile, and not homogenize and diffuse light having an acceptance range outside of the second angular acceptance range, and direct the homogenized and diffused light toward a second eye box at a second location. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification