BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described according to the appended drawings in which:
FIG. 1 is a schematic cross-sectional view of a conventional organic light-emitting diode device;
FIG. 2(
a) is a schematic top view of an OLED in accordance with an embodiment of the present invention;
FIG. 2(
b) is a cross-sectional view of FIG. 2(a);
FIG. 2(
c) is a cross-sectional view in accordance with another embodiment of the present invention;
FIGS. 3(
a)-3(b) are schematic top views of OLEDs in accordance with different embodiments of the present invention; and
FIGS. 4(
a)-4(e) are schematic top views of OLEDs in accordance with different embodiments of the present invention.
PREFERRED EMBODIMENT OF THE PRESENT INVENTION
FIG. 2(
a) is a schematic top view of an OLED 20 with a heat dissipation structure according to an embodiment of the present invention. FIG. 2(b) is a cross-sectional view obtained by turning the sectional view of the OLED 20 taken along the sectional line A-A in FIG. 2(a) by 180°, so the transparent substrate 21 is at the lower part of the figure. Moreover, the anode layer 23 in FIG. 2(b) is also made of a transparent material, so the anode layer 23 is not shown in FIG. 2(a).
As shown in FIG. 2(b), the OLED 20 includes a substrate 21, a transparent anode layer 23, a metal layer 24, a light-emitting layer 25, a cathode layer 27, an external anode 22, and an external cathode 26. The anode layer 23 is formed on the substrate 21. The metal layer 24 is formed on the anode layer 23. The light-emitting layer 25 is formed on the anode layer 23 and covers the metal layer 24. The cathode layer 27 is formed on the light-emitting layer 25. The external anode 22 is connected to the anode layer 23, and the external cathode 26 is connected to the cathode layer 27.
The metal layer 24, due to having a high thermal conductivity, conducts the heat generated during the operation of the light-emitting layer 25 to the external anode 22. The cathode layer 27 made of Al, due to having a good thermal conductivity, also conducts the heat generated during the operation of the light-emitting layer 25 to the external cathode 26.
In addition to natural air cooling, the external anode 22 and external cathode 26 can be cooled down by heat dissipation, or a cooling, heat dissipation device can be installed to quickly conduct the heat generated during the operation of the light-emitting layer 25 to the outside. The cooling, heat dissipation process can be performed by heat pipes or heat sinks. The material of the metal layer can be one selected from among Ag, Ag alloy, Al, Mo—Al alloy, Cr, and so on.
The tips on the metal layer 24 resulting from an etch process may cause discontinuity of the coating layer of the light-emitting layer 25 and abnormal light emission. Therefore, an insulating material layer 29 is needed to wrap the metal layer 24 of the OLED 20a, as shown in FIG. 2(c), so as to produce a flattening effect, thereby eliminating the discontinuity of the coating layer of the light-emitting layer 25.
As shown in the schematic top view of FIG. 2(a), the metal layer 24 covers a part of the light-emitting layer 25. The shape of the effective light-emitting areas of the light-emitting layer 25 is not limited to the plurality of rectangles in FIG. 2(a), but can be a plurality of arbitrary polygons. As shown in FIG. 3(a), the shape of the effective light-emitting areas of the light-emitting layer 25 in the OLED 30a is a plurality of circles. As shown in FIG. 3(b), the shape of the effective light-emitting areas of the light-emitting layer 25 in the OLED 30b is a plurality of honeycombs.
As shown in the schematic top view in FIG. 2(a), the OLED 20 includes an external anode 22 adjacent to three sides and an external cathode 26 at one side. Referring to FIG. 4(a), the OLED 40a includes an external cathode 26 adjacent to three sides and an external anode 22 at one side. Referring to FIG. 4(b), the OLED 40b includes an external cathode 26 at two opposite sides and an external anode 22 at two opposite sides. Referring to FIG. 4(c), the OLED 40c includes an external cathode 26 at one side and an external anode 22 at the opposite side. Referring to FIG. 4(d), the OLED 40d includes an external cathode 26 at one side and an external anode 22 at two opposite sides. Referring to FIG. 4(e), the OLED 40e includes an external cathode 26 at two opposite sides and an external anode 22 at one side. In the present invention, the number and arrangement of the external anode 22 and external cathode 26 are not limited to those, and can be varied as required.
The aforementioned descriptions of the present invention are intended to be illustrative only. Numerous alternative methods may be devised by persons skilled in the art without departing from the scope of the following claims.
Patent Application
20080030127
