Multicolor phosphor-converted LED array
An array of phosphor pixels is positioned on an array of semiconductor LED pixels with thermally curable adhesive between them. Selected LED pixels of the array are electrically activated; resulting heat cures the adhesive to attach the corresponding phosphor pixel to the activated LED pixel and to release the corresponding phosphor pixel from a carrier. Removal of the carrier removes unattached phosphor pixels, leaving behind phosphor pixels attached to the LED pixels that were activated. The process can be repeated for phosphor pixels of different colors.
1. An apparatus comprising:
a semiconductor LED array comprising multiple semiconductor LED pixels;
a first set of multiple phosphor pixels, (i) each phosphor pixel of the first set being positioned over a light emitting surface of a corresponding LED pixel of a first subset of the LED pixels and attached to that corresponding LED pixel by a thermally curable adhesive in a cured state, (ii) a second subset of the LED pixels having no corresponding phosphor pixel of the first set attached thereto; and
a second set of multiple phosphor pixels arranged on a carrier substrate, each phosphor pixel of the second set having a corresponding layer of the thermally curable adhesive, in an uncured state, on a surface of the phosphor pixel opposite the carrier substrate,
the phosphor pixels of the first and second sets being arranged on the LED array and the carrier substrate, respectively, so that with the LED array and the carrier substrate suitably aligned substantially parallel to each other with the light emitting surfaces of the LED pixels facing the phosphor pixels of the second set, (i) each phosphor pixel of the first set is aligned with a corresponding area of the carrier substrate that lacks a phosphor pixel of the second set, and (ii) each phosphor pixel of the second set is aligned with a corresponding one of the LED pixels that lacks a phosphor pixel of the first set.
2. The apparatus of claim 1 , further comprising one or more metal traces or tie bars arranged and connected so as to enable selective electrical operation of selected ones of the semiconductor LED pixels.
3. The apparatus of claim 1 , the phosphor pixels of the first set having corresponding thicknesses less than thickness of any phosphor pixel of the second set.
4. The apparatus of claim 1 , the thermally curable adhesive having a cure temperature between about 100° C. and about 150° C.
5. The apparatus of claim 1 , the thermally curable adhesive including a silicone.
6. The apparatus of claim 1 , the thermally curable adhesive having a refractive index between about 1.4 and about 1.6.
7. The apparatus of claim 1 , the phosphor pixels of the first or second sets including one or more of phosphor/silicone, ceramic phosphor, phosphor in glass, or phosphor on glass.
8. The apparatus of claim 1 , the phosphor pixels of the first and second sets being all a single color.
9. The apparatus of claim 1 , the LED array and the carrier substrate being aligned substantially parallel to each other with the light emitting surfaces of the LED pixels facing the phosphor pixels of the second set, so that (i) each phosphor pixel of the first set is aligned with a corresponding area of the carrier substrate that lacks a phosphor pixel of the second set, and (ii) each phosphor pixel of the second set is aligned with a corresponding one of the LED pixels that lacks a phosphor pixel of the first set.
10. The apparatus of claim 9 , the adhesive on the phosphor pixels of the second set being in contact with the light emitting surfaces of the corresponding LED pixels.
11. The apparatus of claim 1 , the phosphor pixels of the second set being attached to the carrier substrate by a UV releasable adhesive in an adhered state, the LED pixels being UV emitters.
12. The apparatus of claim 11 , areas of the carrier substrate, that lack a phosphor pixel of the second set, having thereon a layer of the UV releasable adhesive in a released state.
13. The apparatus of claim 1 , the phosphor pixels of the second set being attached to the carrier substrate by a thermally releasable adhesive in an adhered state.
14. The apparatus of claim 13 , the thermally releasable adhesive having a release temperature between about 150° C. and about 220° C.
15. The apparatus of claim 13 , areas of the carrier substrate, that lack a phosphor pixel of the second set, having thereon a layer of the thermally releasable adhesive in a released state.
16. The apparatus of claim 1 , the phosphor pixels of the first set including phosphor pixels of one or more colors, the phosphor pixels of the second set including phosphor pixels of at least one color different from the color of any phosphor pixel of the first set.
17. The apparatus of claim 16 , the phosphor pixels of the second set being all a single color.
18. The apparatus of claim 17 , the phosphor pixels of the first set being all a single color.
19. The apparatus of claim 17 , the phosphor pixels of the first set including at least two different colors.
20. The apparatus of claim 17 , the phosphor pixels of the first set including at least three different colors.