Methods for uniform LED lighting
In accordance with certain embodiments, a substrate having first and second groups of light-emitting elements having different distributions in one or more optical characteristics thereon is deformed such that the first and second groups of light-emitting elements are not simultaneously observable.
1. A method of providing illumination, the method comprising:
providing a substrate having disposed thereon first and second groups of light-emitting elements (LEEs), the first and second groups having distributions of an optical characteristic (i) different from each other when all LEEs of each group are illuminated and (ii) distinguishable by a human observer when all of the LEEs of each group are (a) illuminated and (b) viewed directly by the human observer; and
thereafter, deforming without damaging the substrate into a deformed configuration such that, in the deformed configuration, tithe first group of LEEs and the second group of LEEs are not simultaneously observable, (ii) the second group of LEEs is directly observable by the human observer, thereby providing direct illumination, (iii) none of the LEEs of the first group of LEEs are directly visible by the human observer, whereby the first group of LEEs provides only indirect illumination, and (iv) all of the LEEs in the second group of LEEs emit white light.
2. The method of claim 1 , wherein the optical characteristic comprises at least one of correlated color temperature (CCT), color rendering index (CRI), R9, or light intensity.
3. The method of claim 1 , wherein a distribution of the optical characteristic of the first group is less than three times as large as the distribution of the optical characteristic of the second group.
4. The method of claim 1 , wherein a distribution of the optical characteristic of the first group is less than 1.5 times as large as the distribution of the optical characteristic of the second group.
5. The method of claim 1 , wherein a distribution of the optical characteristic of the first group is between 1.5 times and 10 times the distribution of the optical characteristic of the second group.
6. The method of claim 1 , wherein an average of the optical characteristic of the first group is approximately equal to an average of the optical characteristic of the second group.
7. The method of claim 1 , wherein, in the deformed configuration, light emitted by the first group is emitted in a first direction substantially different from a second direction in which light is emitted by the second group, and further comprising reflecting a portion of the light emitted by the second group, thereby producing reflected light propagating in the first direction.
8. The method of claim 1 , wherein the substrate is flexible.
9. The method of claim 1 , further comprising disposing an optic over at least a portion of at least one of the first group or the second group.
10. The method of claim 9 , wherein the optic comprises at least one of a diffuser, a refractive optic, a reflective optic, a total internal reflection optic, or a Fresnel optic.
11. The method of claim 1 , wherein all LEEs on the substrate are within the first group of LEEs or the second group of LEEs.
12. The method of claim 1 , wherein, in the deformed configuration, the first and second groups of LEEs emit light in substantially opposite directions.
13. The method of claim 1 , further comprising mounting the substrate in the deformed configuration above the human observer, the direct illumination from the second group of LEEs being emitted downward toward the human observer, and the indirect illumination from the first group of LEEs being emitted upward away from the human observer.