Organic light-emitting device for lighting

Abstract

The present invention relates to an organic light-emitting device for lighting, and more specifically relates to an organic light-emitting device for lighting whereby it is possible to achieve excellent brightness by increasing the light-emitting area per unit area of an organic light-emitting element. For this purpose, the present invention provides an organic light-emitting device comprising: a first substrate and a second substrate disposed facing each other; a frame section which is formed between the first substrate and the second substrate, and is formed on the periphery of the first substrate and the second substrate so as to hermetically close the space between the first substrate and the second substrate; and a flexible organic light-emitting element which is disposed inside of the space, and of which at least one part has a curved surface.

Claims

1. An organic light-emitting device for lighting, comprising: first and second substrates facing each other to define a space there between, wherein a light-scattering pattern is formed on a surface of the second substrate facing the space and a reflective material is applied onto a surface of the light-scattering pattern; a frame disposed between the first and second substrates along peripheries of the first and second substrates to hermetically seal a space between the first and second substrates; and a plurality of flexible organic light-emitting elements disposed within the space, at least one portion of the flexible organic light-emitting elements having a curved surface.

2. The organic light-emitting device of claim 1, wherein a reflector facing the space is provided on areas of the first substrate, the second substrate, and the frame except for an area through which light generated by the flexible organic light-emitting element is emitted outwards.

3. The organic light-emitting device of claim 1, wherein the flexible organic light-emitting element comprises: a metal electrode; an organic light-emitting layer disposed on the metal electrode; a transparent electrode disposed on the organic light-emitting layer; and a flexible base disposed on the transparent electrode.

4. The organic light-emitting device of claim 1, wherein the flexible organic light-emitting element comprises: a flexible base; a first transparent electrode disposed on the flexible base; an organic light-emitting layer disposed on the first transparent electrode; and a second transparent electrode disposed on the organic light-emitting layer.

5. The organic light-emitting device of claim 3, wherein the flexible organic light-emitting element further comprising a light extraction layer disposed on a front portion thereof through which light generated by the organic light-emitting layer is emitted outwards.

6. The organic light-emitting device of claim 1, wherein a filler is disposed within the space to form a filler layer, and a plurality of light-scattering particles are distributed in the filler layer.

7. The organic light-emitting device of claim 1, wherein a light-scattering pattern is formed on one of opposite surfaces of the first substrate.

8. The organic light-emitting device of claim 4, wherein the flexible organic light-emitting element further comprising a light extraction layer disposed on a front portion thereof through which light generated by the organic light-emitting layer is emitted outwards.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a first embodiment;

(2) FIG. 2 illustrates a simulation result obtained from the organic light-emitting device for lighting according to the first embodiment using light tools;

(3) FIG. 3 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a second embodiment;

(4) FIG. 4 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a third embodiment;

(5) FIG. 5 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a fourth embodiment;

(6) FIG. 6 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a fifth embodiment;

(7) FIG. 7 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a sixth embodiment;

(8) FIG. 8 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a seventh embodiment;

(9) FIG. 9 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to an eighth embodiment; and

(10) FIG. 10 is a cross-sectional view schematically illustrating an organic light-emitting device for lighting according to a ninth embodiment.

MODE FOR INVENTION

(11) Hereinafter, reference will be made to an organic light-emitting device for lighting according to the present disclosure in detail, embodiments of which are illustrated in the accompanying drawings.

(12) In the following description, detailed descriptions of known functions and components incorporated herein will be omitted in the case that the subject matter of the present disclosure is rendered unclear by the inclusion thereof.

(13) As illustrated in FIG. 1, an organic light-emitting device for lighting 100 according to a first embodiment includes a first substrate 110, a second substrate 120, a frame 130, and a flexible organic light-emitting diode (OLED) 140.

(14) The first and second substrates 110 and 120 are disposed to face each other. In the first embodiment, light generated by the flexible OLED 140 is emitted outwards through the first substrate 110. In this regard, the first substrate 110 may be formed from a transparent plastic material or transparent glass. Here, the second substrate 120 may be formed from the same material as the first substrate 110.

(15) The frame 130 is dispose between the first substrate 110 and the second substrate 120 that face each other. The frame 130 is formed along the peripheries of the first substrate 110 and the second substrate 120 to define a space between the first substrate 110 and the second substrate 120, i.e. a space in which the flexible OLED 140 is disposed, while hermetically sealing the space in order to protect the flexible OLED 140 from the external environment.

(16) According to the first embodiment, a reflector (not shown) may be disposed on predetermined surfaces of the second substrate 120 and the frame 130 except for the first substrate 110 through which light generated by the flexible OLED 140 is emitted outwards, more particularly, surfaces of the second substrate 120 and the frame 130 facing the space, in order to improve the luminance of organic light-emitting device for lighting 100 by focusing light emitted by the flexible OLED 140 in the direction of the first substrate 110. This configuration can reflect light that would otherwise be directed sidewards or backwards in the direction of the first substrate 110. Here, the reflector (not shown) may be formed by applying a reflective material to the predetermined surfaces or may be provided as separate members attached to the predetermined surfaces.

(17) The flexible OLED 140 is a light source of the organic light-emitting device for lighting 100, and is disposed within the sealed space defined by the first substrate 110, the second substrate 120, and the frame 130. As illustrated in the drawing, the flexible OLED 140 is configured such that at least one portion thereof has a curved surface. When the OLED 140 has a curved profile that is bent several times, the light-emitting area per the unit area thereof can be increased to be greater than that of a flat OLED. This can consequently improve the luminance of the organic light-emitting device for lighting 100.

(18) According to the first embodiment, the flexible OLED 140 may be a laminated structure including a metal electrode 141, an organic light-emitting layer 142, a transparent electrode 143, and a flexible base 144. The metal electrode 141 is an electrode acting as the cathode of the OLED 140, and may be formed from a metal having a smaller work function in order to facilitate electron injection into the organic light-emitting layer 142. For example, the metal electrode 141 may be a metal thin film formed from Al, Al:Li, or Mg:Ag.

(19) In addition, the transparent electrode 143 is disposed on the flexible base 144 to face away from the metal electrode 141. The transparent electrode 143 is an electrode acting as the anode of the OLED 140, and may be formed from a material having a greater work function in order to facilitate hole injection into the organic light-emitting layer 142. For example, the transparent electrode 143 may be formed from a material allowing light generated by the organic light-emitting layer 142 to easily pass through or a flexible polymer material.

(20) The organic light-emitting layer 142 is formed between the transparent electrode 143 acting as the anode and the metal electrode 141 acting as the cathode. Although not specifically illustrated, the organic light-emitting layer 142 may include a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) sequentially laminated on the transparent electrode 143. According to the structure of the organic light-emitting layer 142, when a forward voltage is applied between the transparent electrode 143 acting as the anode and the metal electrode 141 acting as the cathode, electrons migrate from the metal electrode 141 to the EML through the EIL and the ETL, and holes migrate from the transparent electrode 143 to the EML through the HIL and the HTL. Electrons and holes injected into the EML as above recombine with each other to generate excitons. When such excitons transmit from an excited state to a ground state, light is emitted. The brightness of emission light is proportional to the amount of current flowing between the transparent electrode 143 and the metal electrode 141. When the OLED 140 according to the first embodiment is a white OLED, the EML may have, for example, a laminated structure including a high-molecular EML that emits blue light and a low-molecular EML that emits orange-red light, as well as a variety of other structures, to emit white light. In addition, the organic light-emitting layer 142 may have a tandem structure. That is, a plurality of organic light-emitting layer 142 may be provided to alternate with interconnecting layers acting as charge generation layers.

(21) FIG. 2 illustrates a simulation result obtained using light tools in order to measure the intensity of the organic light-emitting device for lighting according to the first embodiment. Referring to FIG. 2, it is appreciated that the intensity of light is enhanced as the unit area increases. The unit area increases with increases in the angle ? of the OLED in FIG. 1, i.e. the degree of bending of the curved surface. It is thereby appreciated that, when the flexible OLED with at least one portion thereof having a curved surface is provided as a light source, the light-emitting area per the unit area, i.e. the intensity of light, can be increased. This consequently improves the luminance of the organic light-emitting device for lighting.

(22) In addition, according to the first embodiment, in order to improve the light extraction efficiency of the flexible OLED 140, a light extraction layer (not shown) may be formed on the front surface of the flexible base 144 that is forward of the organic light-emitting layer 142 or on the rear surface of the flexible base 144, i.e. between the flexible base 144 and the transparent electrode 143.

(23) Hereinafter, reference will be made to an organic light-emitting device for lighting according to a second embodiment in conjunction with FIG. 3.

(24) FIG. 3 is a cross-sectional view schematically illustrating the organic light-emitting device for lighting according to the second embodiment.

(25) As illustrated in FIG. 3, the organic light-emitting device for lighting 200 according to the second embodiment includes a first substrate 110, a second substrate 120, a frame 130, and a flexible OLED 240.

(26) The components of the second embodiment are substantially identical to those of the first embodiment except for the structure of the flexible OLED. The same reference numerals will be used to designate the same components, and descriptions thereof will be omitted.

(27) The flexible OLED 240 according to the second embodiment is a transparent OLED having a double-sided light-emitting structure. In this regard, the flexible OLED 240 according to the second embodiment includes a flexible base 241 and a first transparent electrode 242, an organic light-emitting layer 243, and a second transparent electrode 244 sequentially laminated on the base 241. Here, the curved structure of the flexible OLED 240 according to the second embodiment may be configured the same as the curved structure of the flexible OLED (140 in FIG. 1) according to the first embodiment.

(28) When the flexible OLED 240 according to the second embodiment generates light, light traveling in the direction of the second substrate 120 is reflected from a reflector (not shown) disposed on the surface of the second substrate 120 in the direction of the first substrate 110, whereby the organic light-emitting device for lighting 200 can obtain a luminance enhancement effect the same as that of the first embodiment.

(29) Hereinafter, reference will be made to an organic light-emitting device for lighting according to a third embodiment in conjunction with FIG. 4.

(30) FIG. 4 is a cross-sectional view schematically illustrating the organic light-emitting device for lighting according to the third embodiment.

(31) As illustrated in FIG. 4, the organic light-emitting device for lighting 300 according to the third embodiment includes a first substrate 110, a second substrate 120, a frame 130, a flexible OLED 140, and a filler layer 350.

(32) The third embodiment is substantially identical to the first embodiment except for the filler layer being disposed in the space. The same reference numerals will be used to designate the same components, and descriptions thereof will be omitted.

(33) The filler layer 350 is formed by filling the interior of the space defined by the first substrate 110, the second substrate 120, and the frame 130 with a resin material, such as PMA. The filler layer 350 serves to fix the flexible OLED 140, i.e. hold the flexible OLED 140 such that the flexible OLED 140 maintains the shape thereof. A plurality of light-scattering particles 351 are distributed in the filler layer 350. When the plurality of light-scattering particles 351 are distributed in the filler layer 350, light generated by the flexible OLED 140 can be scattered while passing through the filler layer 350, i.e. paths on which light travels can be diversified or complexified. This can reduce total reflection occurring at the interface between the first substrate 110 and the air, thereby further improving the luminance of the organic light-emitting device for lighting 300.

(34) FIG. 5 illustrates an organic light-emitting device for lighting 400 according to a fourth embodiment. The organic light-emitting device for lighting 400 according to the fourth embodiment is substantially identical to the third embodiment, except that the flexible OLED 240 according to the second embodiment is used in place of the flexible OLED (140 in FIG. 1) according to the first embodiment. Thus, effects that the organic light-emitting device for lighting 400 according to the fourth embodiment can realize are the same as or similar to those of the organic light-emitting device for lighting (300 in FIG. 4) according to the third embodiment.

(35) Hereinafter, reference will be made to an organic light-emitting device for lighting according to a fifth embodiment in conjunction with FIG. 6.

(36) FIG. 6 is a cross-sectional view schematically illustrating the organic light-emitting device for lighting according to the fifth embodiment.

(37) As illustrated in FIG. 6, the organic light-emitting device for lighting 500 according to the fifth embodiment includes a first substrate 110, a second substrate 120, a frame 530, and a flexible OLED 240.

(38) The fifth embodiment is substantially identical to the second embodiment except for the frame. The same reference numerals will be used to designate the same components, and descriptions thereof will be omitted.

(39) The organic light-emitting device for lighting 500 according to the fifth embodiment is configured such that light is emitted through a side surface, i.e. through one portion of the frame 530, instead of through the front surface, i.e. in the direction of the first substrate 110. In this regard, one of four sections of the frame 530 disposed along the peripheries of the first substrate 110 and the second substrate 120 may be formed from a transparent material. Then, reflectors (not shown) may be disposed on the surface of the first substrate 110 facing the flexible OLED 240 as well as on the surfaces of the second substrate 120 and the other three sections of the frame.

(40) FIG. 7 illustrates an organic light-emitting device for lighting 600 according to a sixth embodiment. The organic light-emitting device for lighting 600 according to the sixth embodiment is substantially identical to the fifth embodiment, except that a filler layer 350 and light-scattering particles 351 are further included in the space. This can consequently further improve the luminance of the organic light-emitting device for lighting 600.

(41) Hereinafter, reference will be made to an organic light-emitting device for lighting according to a seventh embodiment in conjunction with FIG. 8.

(42) FIG. 8 is a cross-sectional view schematically illustrating the organic light-emitting device for lighting according to the seventh embodiment.

(43) As illustrated in FIG. 8, the organic light-emitting device for lighting 700 according to the seventh embodiment includes a first substrate 710, a second substrate 720, a frame 130, and a flexible OLED 140.

(44) The seventh embodiment is substantially identical to the first embodiment except for the structures of the first and second substrates. The same reference numerals will be used to designate the same components, and descriptions thereof will be omitted.

(45) According to the seventh embodiment, light-scattering patterns 711 are formed on the outer surface and the inner surface of the first substrate 710, and a light-scattering pattern 721 is formed on the inner surface of the second substrate 720 facing the flexible OLED 140. The surface of the light-scattering pattern 721 formed on the inner surface of the second substrate 720 may have a reflective material applied thereto.

(46) When the light-scattering patterns 711 and 721 are formed on the surfaces of the first substrate 710 and the second substrate 720 as described above, the same effect as obtained from the light-scattering particles (351 in FIG. 7) formed according to the third embodiment can be obtained. That is, the luminance of the organic light-emitting device for lighting 700 can be further improved.

(47) FIG. 9 illustrates an organic light-emitting device for lighting 800 according to an eighth embodiment. The organic light-emitting device for lighting 800 according to the eighth embodiment is substantially identical to the seventh embodiment, except that the flexible OLED 240 according to the second embodiment is used in place of the flexible OLED (140 in FIG. 1) according to the first embodiment. Thus, effects that the organic light-emitting device for lighting 800 according to the eighth embodiment can realize are the same as or similar to those of the organic light-emitting device for lighting (700 in FIG. 8) according to the seventh embodiment.

(48) FIG. 10 illustrates an organic light-emitting device for lighting 900 according to a ninth embodiment. The organic light-emitting device for lighting 900 according to the ninth embodiment is substantially identical to the second embodiment, except that one more flexible OLED 240 is provided. Since the number of the flexible OLEDs 240 acting as a light source is doubled, the intensity of the OLED is doubled that of the second embodiment, thereby doubling the luminance of the OLED.

(49) The foregoing descriptions of specific exemplary embodiments of the present disclosure have been presented with respect to the drawings. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed herein, and many modifications and variations are obviously possible for a person having ordinary skill in the art in light of the above teachings.

(50) It is intended therefore that the scope of the present disclosure not be limited to the foregoing embodiments, but be defined by the Claims appended hereto and their equivalents.

(51) TABLE-US-00001 [Description of the Reference Numerals in the Drawings] 100: organic light-emitting device for lighting 110: first substrate 120: second substrate 130: frame 140: flexible OLED 141: metal electrode 142: organic light-emitting layer 143: transparent electrode 144: flexible base