Segmented OLED
An OLED device comprising an array of bottom-emitting OLED segments, each separated by a non-emitting gap, arranged on a common transparent substrate; wherein each OLED segment is defined by a transparent bottom electrode segment together with a top electrode and organic layers for light emission between the top electrode and bottom electrode segments; where each segmented bottom electrode is electrically connected to an individual power feed, wherein at least some of the power feeds are arranged between the bottom electrode segments and the transparent substrate within the emission light path; and includes at least one refraction-reducing material located between the segmented bottom electrode and the transparent substrate. The refraction-reducing material is located between the bottom side of the power feed and the upper side of the transparent substrate; and/or between the bottom side of the bottom electrode segments and the upper side of the power feed; and/or between the lateral spaces separating the individual power feeds.
1 . An OLED device comprising an array of multiple independent bottom-emitting OLED segments arranged on a common transparent substrate, each individual OLED segment being separated by a non-emitting gap;
wherein each OLED segment is defined by a transparent bottom electrode segment which is not in electrical contact with any other electrode segment, together with a top electrode and organic layers for light emission between the top electrode and bottom electrode segments;
where each segmented bottom electrode is electrically connected to an individual power feed, wherein at least some of the power feeds are arranged between the bottom electrode segments and the transparent substrate within the emission light path; and
includes at least one refraction-reduction material located between the segmented bottom electrode and the transparent substrate to reduce visibility of individual power feeds.
2 . The OLED device of claim 1 wherein the refraction-reduction material is located between the bottom side of the bottom electrode segments and the upper side of the power feeds; and/or between the bottom side of the power feeds and the upper side of the transparent substrate; and/or between the lateral spaces separating the individual power feeds.
3 . The OLED device of claim 2 wherein the refraction-reduction material is a continuous layer located between the bottom side of the bottom electrode segments and the upper side of the power feeds.
4 . The OLED device of claim 3 wherein the refraction-reduction material is additionally located in the lateral spaces separating the individual power feeds.
5 . The OLED device of claim 2 wherein the refraction-reduction material is located between the bottom side of the bottom electrode segments and the upper side of the power feeds; and wherein there is an additional insulating layer located between the upper surface of the power feeds and the bottom surface of the bottom electrode segment.
6 . The OLED device of claim 5 wherein the insulating layer is located between the refraction-reduction material and the bottom side of the bottom electrode segments.
7 . The OLED device of claim 1 where the reflectance difference (DR) between the regions of the transparent substrate where the power feeds are located and the regions of the transparent substrate where the gaps between the power feeds are located is 5% or less.
8 . The OLED device of claim 7 where the ratio (higher RI/lower RI) of the refractive index RI of the power feed and the refractive index RI of the refraction-reduction material is in the range of 1.00 to 1.06.
9 . The OLED devices of claim 8 where the refraction-reduction material comprises two or more inorganic materials with different refractive indexes.
10 . The OLED device of claim 9 where the power feeds are formed from conductive metal oxide and the refraction-reduction material is a mixture of Nb 2 O 5 and SiO 2 .
11 . The OLED device of claim 8 where the refraction-reduction material comprises a suspension of inorganic particles in an organic polymer.
12 . The OLED device of claim 11 where the power feeds are formed from conductive metal oxide and the refraction-reduction material is a mixture of inorganic nanoparticles suspended in a polymer matrix comprising polymeric siloxanes with high molecular weight organic functional groups.
13 . The OLED devices of claim 1 —where all of the OLED segments in the array emit the same color of light.
14 . The OLED device of claim 1 where some of the OLED segments emit a different color of light from other segments.
15 . The OLED device of claim 1 where at least one of the OLED segments in the array is located within and is entirely surrounded by another OLED segment.
16 . The OLED device of claim 1 where the OLED device is used for exterior automotive lighting applications.
17 . The OLED device of claim 1 wherein:
for devices with a total emission area of 500 cm 2 or less, the individual OLED segments have an emission area of at least 1 mm 2 ; or
for devices with a total emission area of greater than 500 cm 2 , the individual OLED segments have an emission area of at least 0.25 cm 2 .