Organic electroluminescent element and lighting device
| Title: | Organic electroluminescent element and lighting device |
|---|---|
| Patent Number: | 9,184,414 |
| Publication Date: | November 10, 2015 |
| Appl. No: | 13/576420 |
| Application Filed: | April 22, 2011 |
| Abstract: | An organic EL device comprises: a light-transmissive substrate; a transparent electrode; an organic emitting layer; and an opposing electrode. A light-extraction layer provided by layering a high refractive index layer adjoining the transparent electrode and a low refractive index layer adjoining the light-transmissive substrate includes recess-protrusion units each provided by a protrusion and a recess at an interface between the high refractive index layer and the low refractive index layer. In at least one of the recess-protrusion units, a distance from the interface between the high refractive index layer and the low refractive index layer to an interface between the transparent electrode and the high refractive index layer is equal to or more than an optical coherence length and a height of the protrusion, a width of the protrusion and a gap between the protrusion and another protrusion adjoining the protrusion across the recess is 1 μm or more. |
| Inventors: | Naraoka, Ryo (Sodegaura, JP); Fukuda, Masahiko (Sodegaura, JP); Kuma, Hitoshi (Sodegaura, JP) |
| Assignees: | IDEMITSU KOSAN CO., LTD. (Tokyo, JP) |
| Claim: | 1. An organic electroluminescence device, comprising: a transparent electrode; an opposing electrode; an organic emitting layer provided between the transparent electrode and the opposing electrode; and a light-transmissive substrate, wherein a light-extraction layer is provided adjacent to a first side of the transparent electrode opposite to a second side of the transparent electrode facing the organic emitting layer, the light-extraction layer comprises a high refractive index layer and a low refractive index layer sequentially layered on the transparent electrode, the light-transmissive substrate is provided adjacent to the low refractive index layer, the light-extraction layer is placed above the opposing electrode, the high refractive index layer comprises a plurality of recess-protrusion units each provided by a protrusion and a recess at an interface between the high refractive index layer and the low refractive index layer, in at least one of the plurality of recess-protrusion units, a distance d 1 from the interface between the high refractive index layer and the low refractive index layer to an interface between the transparent electrode and the high refractive index layer is 3 μm or more, and a height d 2 of the protrusion, a width d 3 of the protrusion and a gap d 4 between the protrusion and another protrusion adjoining with the protrusion across the recess are 1 μm or more. |
| Claim: | 2. The organic electroluminescence device according to claim 1 , wherein the organic electroluminescence device satisfies the following formulae (1), (2) and (3), | n 1 −n H |<0.2 (1), | n 2 −n L |<0.2 (2), and n H >n L (3), wherein n 1 represents a refractive index of the transparent electrode, n L represents a refractive index of the low refractive index layer, n H represents a refractive index of the high refractive index layer and n 2 represents a refractive index of the light-transmissive substrate, and the refractive indexes n 1 , n L , n H and n 2 represent values at a wavelength of 550 nm. |
| Claim: | 3. The organic electroluminescence device according to claim 1 , wherein the height d 2 of the protrusion and the width d 3 of the protrusion satisfy a relationship of 2.0>d 2 /d 3 >0.2. |
| Claim: | 4. The organic electroluminescence device according to claim 1 , wherein a side face of the protrusion along a height direction is inclined at 35 degrees or less relative to a light-extraction direction of a light generated by the organic emitting layer. |
| Claim: | 5. The organic electroluminescence device according to claim 4 , wherein the side face of the protrusion of the high refractive index layer has a shape extending along the light-extraction direction of the light generated by the organic emitting layer. |
| Claim: | 6. The organic electroluminescence device according to claim 5 , wherein an upper face of the protrusion of the high refractive index layer has a shape extending along a direction orthogonal to the light-extraction direction of the light generated by the organic emitting layer. |
| Claim: | 7. The organic electroluminescence device according to claim 1 , wherein the height d 2 of the protrusion, the width d 3 of the protrusion and the gap d 4 between the protrusion and another protrusion adjoining with the protrusion across the recess are 5 μm or more. |
| Claim: | 8. The organic electroluminescence device according to claim 1 , wherein an electron transporting zone having a thickness of 70 nm or more is provided between the opposing electrode and the organic emitting layer. |
| Claim: | 9. An illumination unit comprising the organic electroluminescence device according to claim 1 . |
| Claim: | 10. The organic electroluminescence device according to claim 1 , wherein the height d 2 of the protrusion and the width d 3 of the protrusion satisfy a relationship of 1.0>d 2 /d 3 >0.5. |
| Claim: | 11. The organic electroluminescence device according to claim 2 , wherein the refractive index n 1 of the transparent electrode is in a range of from 1.8 to 2.2. |
| Claim: | 12. The organic electroluminescence device according to claim 2 , wherein the refractive index n 2 of the light-transmissive substrate is in a range of from 1.4 to 1.6. |
| Claim: | 13. The organic electroluminescence device according to claim 2 , wherein the refractive index n H of the high refractive index layer is in a range of from 1.8 to 2.2. |
| Claim: | 14. The organic electroluminescence device according to claim 2 , wherein the refractive index n L of the low refractive index layer is in a range from 1.4 to 1.6. |
| Claim: | 15. The organic electroluminescence device according to claim 1 , wherein the height d 2 , the width d 3 and the gap d 4 are 5 μm or more. |
| Claim: | 16. The organic electroluminescence device according to claim 1 , wherein the height d 2 , the width d 3 and the gap d 4 are 20 μm or more. |
| Claim: | 17. The organic electroluminescence device according to claim 1 , wherein the light-transmissive substrate comprises a light-transmissive member having a light transmittance of 50% or more in a visible light range of 400 nm to 700 nm. |
| Claim: | 18. The organic electroluminescence device according to claim 1 , wherein the light-transmissive substrate is a glass plate, or a polymer plate. |
| Claim: | 19. The organic electroluminescence device according to claim 1 , wherein the height d 2 , the width d 3 and the gap d 4 are in a range of from 1 μm to 1 mm. |
| Claim: | 20. The organic electroluminescence device according to claim 1 , wherein the distance d 1 is 3.5 μm or more. |
| Patent References Cited: | 2005/0127832 June 2005 Toguchi et al. 2006/0049745 March 2006 Handa et al. 2006/0284169 December 2006 Park et al. 2007/0254162 November 2007 Kozaki et al. 2008/0176041 July 2008 Sato et al. 2009/0066219 March 2009 Handa et al. 2009/0066220 March 2009 Handa et al. 2011/0175116 July 2011 Usami 2012/0286258 November 2012 Naraoka et al. 1759637 April 2006 101060165 October 2007 2 439 231 December 2007 8 83688 March 1996 2003 297572 October 2003 2004 296438 October 2004 2005 274741 October 2005 2005 317228 November 2005 2005 327689 November 2005 2006 294491 October 2006 2007 287486 November 2007 2007 335253 December 2007 4073510 February 2008 2008 66027 March 2008 4140541 June 2008 4253302 January 2009 4386285 October 2009 2009 272059 November 2009 WO 2010/032652 March 2010 |
| Other References: | Extended European Search Report issued Sep. 4, 2014 in Patent Application No. 11772104.3. cited by applicant U.S. Appl. No. 13/792,600, filed Mar. 11, 2013, Naraoka, et al. cited by applicant Combined Chinese Office Action and Search Report issued Dec. 31, 2014 in Patent Application No. 201180007505.5 (with English Translation and English Translation of Category of Cited Documents). cited by applicant Dai Fu Long , “Modem Light Measurement Mechanism”, First edition, Oct. 1990, 6 pages. cited by applicant |
| Primary Examiner: | Shingleton, Michael |
| Attorney, Agent or Firm: | Oblon, McClelland, Maier & Neustadt, L.L.P. |
| Accession Number: | edspgr.09184414 |
| Database: | USPTO Patent Grants |
| Language: | English |
|---|