Solid state light-emitting devices with improved contrast

• US 9,685,101 B2
• Filed: 04/23/2014
• Issued: 06/20/2017
• Est. Priority Date: 04/23/2014
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: van de Ven, Antony Paul, Jacobson, Benjamin A.
• Primary Examiner(s): PIZARRO CRESPO, MARCOS D
• Application Number:
  US14/259,943
• Publication Number:
  US 20150308634A1
• Time in Patent Office: 1,154 Days
• Field of Search: 362 84
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes

Abstract

Solid state light emitting devices and display devices include at least one filtering material arranged to provide at least one spectral notch comprising a wavelength of greatest attenuation in at least one spectrum between dominant wavelengths of solid state light emitters of the light emitting and/or display devices. The at least one spectral notch may be non-overlapping with a majority or an entirety of spectral output of each solid state light emitter. Filtering material may be arranged in a light path between at least some emitters and) at least one light output surface of a light emitting or display device, with the filtering material(s) arranged to receive incident ambient light, such that at least a portion of reflected ambient light exiting the device exhibits at least one spectral notch.

Claims

1. A solid state light emitting device comprising:

a plurality of electrically activated solid state light emitters including at least one first solid state light emitter arranged to generate emissions comprising a first dominant wavelength, and at least one second solid state light emitter arranged to generate emissions comprising a second dominant wavelength; and

at least one filtering material arranged in a light path between at least some solid state light emitters of the plurality of electrically activated solid state light emitters and at least one light output surface of the solid state light emitting device, wherein the least one filtering material is arranged to receive ambient light incident on the solid state light emitting device such that at least a portion of reflected ambient light exhibits a first spectral notch, wherein the first spectral notch comprises a wavelength of greatest attenuation between the first dominant wavelength and the second dominant wavelength.

2. The solid state light emitting device of claim 1, wherein a wavelength spectrum corresponding to full width at half maximum (FWHM) attenuation of the first spectral notch is non-overlapping with each of the following spectra:

spectrum corresponding to one-half maximum output of the at least one first solid state light emitter; and

spectrum corresponding to one-half maximum output of the at least one second solid state light emitter.

3. The solid state light emitting device of claim 1, wherein the second dominant wavelength exceeds the first dominant wavelength by at least 40 nm.

4. A display device adapted to display at least one of text and visual images, the display device comprising a plurality of solid state light emitting devices according to claim 1.

5. The solid state light emitting device of claim 1, wherein the at least one light output surface of the solid state lighting emitting device comprises the at least one filtering material.

6. A display device adapted to display at least one of text and visual images, the display device comprising:

a plurality of electrically activated solid state light emitters including at least one first solid state light emitter comprising a first dominant wavelength in a range of from 441 nm to 495 nm, at least one second solid state light emitter comprising a second dominant wavelength in a range of from 496 nm to 570 nm, and at least one third solid state light emitter comprising a third dominant wavelength in a range of from 591 nm to 750 nm;

a first filtering material arranged in a light path between at least some solid state light emitters of the plurality of electrically activated solid state light emitters and at least one light output surface of the display device, wherein the first filtering material is arranged to receive ambient light incident on the display device such that at least a portion of reflected ambient light exhibits a first spectral notch, wherein the first spectral notch comprises a first wavelength of greatest attenuation between the first dominant wavelength and the second dominant wavelength; and

a second filtering material arranged in a light path between at least some solid state light emitters of the plurality of electrically activated solid state light emitters and at least one light output surface of the display device, wherein the second filtering material is arranged to receive ambient light incident on the display device such that at least a portion of reflected ambient light exhibits a second spectral notch, wherein the second spectral notch comprises a second wavelength of greatest attenuation between the second dominant wavelength and the third dominant wavelength.

7. The display device of claim 6, comprising a multi-color sequentially illuminated LED display device.

8. The display device of claim 6, wherein:

the first filtering material comprises at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; and

the second filtering material comprises at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

9. The display device of claim 6, wherein any of the first filtering material and the second filtering material comprises at least one color pigment.

10. The display device of claim 6, further comprising at least one lumiphoric material arranged to receive emissions of at least some emitters of the plurality of electrically activated solid state light emitters and responsively emit lumiphor emissions.

11. The display device of claim 6, further comprising at least one of the following items (a) and (b) arranged in a light path between (i) at least some solid state light emitters of the plurality of electrically activated solid state light emitters and (ii) the at least one light output surface of the display device:

(a) a high pass optical filter arranged to transmit at least some visible light having wavelengths of 420 nm or greater; and

(b) a low pass optical filter arranged to transmit at least some visible light having wavelengths of 700 nm or smaller.

12. The display device of claim 6, wherein the at least one light output surface of the display device comprises at least one of the first filtering material and the second filtering material.

13. A solid state light emitting device comprising:

a plurality of electrically activated solid state light emitters including at least one first solid state light emitter arranged to generate emissions comprising a first dominant wavelength, at least one second solid state light emitter arranged to generate emissions comprising a second dominant wavelength, and at least one third solid state light emitter arranged to generate emissions comprising a third dominant wavelength;

a first filtering material arranged in a light path between at least some solid state light emitters of the plurality of electrically activated solid state light emitters and at least one light output surface of the solid state light emitting device, wherein the first filtering material is arranged to receive ambient light incident on the solid state light emitting device such that at least a portion of reflected ambient light exhibits a first spectral notch, wherein the first spectral notch comprises a first wavelength of greatest attenuation between the first dominant wavelength and the second dominant wavelength; and

a second filtering material arranged in a light path between at least some solid state light emitters of the plurality of electrically activated solid state light emitters and at least one light output surface of the solid state light emitting device, wherein the second filtering material is arranged to receive ambient light incident on the solid state light emitting device such that at least a portion of reflected ambient light exhibits a second spectral notch, wherein the second spectral notch comprises a second wavelength of greatest attenuation between the second dominant wavelength and the third dominant wavelength.

14. The solid state light emitting device of claim 13, wherein a wavelength spectrum corresponding to full width at half maximum (FWHM) attenuation of the first spectral notch and a wavelength spectrum corresponding to full width at half maximum (FWHM) attenuation of the second spectral notch are non-overlapping with each of the following spectra:

spectrum corresponding to one-half maximum output of the at least one first solid state light emitter;

spectrum corresponding to one-half maximum output of the at least one second solid state light emitter; and

spectrum corresponding to one-half maximum output of the at least one third solid state light emitter.

15. The solid state light emitting device of claim 13, wherein the second dominant wavelength exceeds the first dominant wavelength by at least 40 nm, and wherein the third dominant wavelength exceeds the second dominant wavelength by at least 50 nm.

16. The solid state light emitting device of claim 13, wherein:

the first filtering material comprises at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; and

the second filtering material comprises at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

17. The solid state light emitting device of claim 13, wherein any of the first filtering material and the second filtering material comprises at least one color pigment.

18. The solid state light emitting device of claim 13, wherein the first filtering material and the second filtering material are coated on at least some emitters of the plurality of electrically activated solid state light emitters.

19. The solid state light emitting device of claim 13, wherein at least one of the first filtering material and the second filtering material is arranged in a carrier disposed on or over the plurality of electrically activated solid state light emitters.

20. The solid state light emitting device of claim 13, further comprising at least one of the following items (a) and (b) arranged in a light path between (i) at least some solid state light emitters of the plurality of electrically activated solid state light emitters and (ii) the at least one light output surface of the solid state light emitting device:

(a) a high pass optical filter arranged to transmit at least some visible light having wavelengths of 420 nm or greater; and

(b) a low pass optical filter arranged to transmit at least some visible light having wavelengths of 700 nm or smaller.

21. A display device adapted to display at least one of text and visual images, the display device comprising a plurality of solid state light emitting devices according to claim 13.

22. The solid state light emitting device of claim 13, wherein the at least one light output surface of the solid state light emitting device comprises at least one of the first filtering material and the second filtering material.

23. A display device adapted to display at least one of text and visual images, the display device comprising:

a plurality of electrically activated solid state light emitters including a first group of solid state emitters arranged to generate emissions having a first dominant wavelength and a second group of solid state emitters arranged to generate emissions having a second dominant wavelength that differs from the first dominant wavelength by at least 50 nm; and

at least one filtering material arranged in a light path between (i) at least some solid state light emitters of the plurality of electrically activated solid state light emitters and (ii) at least one light output surface of the display device, wherein the at least one filtering material is arranged to receive ambient light incident on the display device such that at least a portion of reflected ambient light exiting the display device exhibits a first spectral notch, wherein the first spectral notch comprises a wavelength of greatest attenuation between the first dominant wavelength and the second dominant wavelength.

24. The display device of claim 23, wherein a wavelength spectrum corresponding to full width at half maximum (FWHM) attenuation of the first spectral notch is non-overlapping with each of the following spectra:

spectrum corresponding to one-half maximum output of the first group of solid state emitters; and

spectrum corresponding to one-half maximum output of the second group of solid state emitters.

25. The display device of claim 23, comprising a multi-color sequentially illuminated LED display device.

26. The display device of claim 23, wherein the at least one filtering material comprises at least one of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

27. The display device of claim 23, wherein the at least one filtering material comprises at least one color pigment.

28. The display device of claim 23, wherein the plurality of electrically activated solid state light emitters includes an array of electrically activated solid state light emitters arranged in multiple vertical columns and multiple horizontal rows.

29. The display device of claim 23, wherein the at least one filtering material is conformally coated on the plurality of electrically activated solid state light emitters.

30. The display device of claim 23, wherein the at least one filtering material is arranged in or on a carrier arranged on or over the plurality of electrically activated solid state light emitters.

31. The display device of claim 23, wherein the plurality of electrically activated solid state light emitters are arranged in a plurality of clusters, and wherein each cluster of the plurality of clusters includes at least one emitter of the first group of solid state light emitters and at least one emitter of the second group of solid state light emitters.

32. The display device of claim 23, further comprising at least one lumiphoric material arranged to receive emissions of at least some emitters of the plurality of electrically activated solid state light emitters and responsively emit lumiphor emissions.

33. The display device of claim 23, wherein the plurality of electrically activated solid state emitters are arranged in a plurality of solid state light emitter packages, and wherein each solid state light emitter package of the plurality of solid state light emitter packages includes at least one emitter of the first group and the second group of solid state emitters.

34. The display device of claim 23, wherein the at least one filtering material is arranged to receive ambient light incident on the display device such that at least a portion of reflected ambient light exiting the display device exhibits a second spectral notch, wherein the second spectral notch is non-coincident with the first spectral notch.

35. The display device of claim 23, wherein:

the plurality of electrically activated solid state light emitters further includes a third group of solid state emitters arranged to generate emissions having a third dominant wavelength that differs from the first dominant wavelength by at least 100 nm and differs from the second dominant wavelength by at least 50 nm; and

the at least one filtering material includes at least one other notch filtering material arranged to receive ambient light incident on the display device such that at least a portion of reflected ambient light exiting the display device exhibits a second spectral notch, wherein the second spectral notch comprises a wavelength of greatest attenuation between the second dominant wavelength and the third dominant wavelength.

36. The display device of claim 23, further comprising at least one of the following items (a) and (b) arranged in a light path between (i) at least some solid state light emitters of the plurality of electrically activated solid state light emitters and (ii) the at least one light output surface of the display device:

(a) a high pass optical filter arranged to transmit at least some visible light having wavelengths of 420 nm or greater; and

(b) a low pass optical filter arranged to transmit at least some visible light having wavelengths of 700 nm or smaller.

37. The display device of claim 23, wherein the at least one light output surface of the display device comprises the at least one filtering material.