Plastic substrate

Abstract

The present application relates to a plastic substrate, a method for producing same, an organic electronic device, and display light source and lighting apparatus. The plastic substrate according to the present application has superb light extraction efficiency and exhibits an excellent surface roughness characteristic. Furthermore, the method for producing the plastic substrate according to the present application can produce the plastic substrate by means of a process in which scattering components are added secondarily. Moreover, the plastic substrate according to the present application can be utilized as a substrate for an organic electronic device, and the organic electronic device can be utilized as display light source and lighting apparatus.

Claims

1. A plastic substrate having a supporting layer, which comprises a polymeric binder and a scattering component contained in a ratio within a range of 0.05% by weight to 3.75% by weight in the polymeric binder and has a thickness in a range of 10 ?m to 130 ?m, and having a haze in a range of 5% to 80%, wherein the polymeric binder comprises a repeating unit of Formula 1 below: ##STR00003## wherein, L is a single bond, an alkylene group, an alkylidene group, an alkynylene group, an arylene group, an alkenylene group, S, S(?O), S(?O).sub.2 or SS, R.sub.1 to R.sub.20 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group or a functional group comprising a halogen atom, a sulfur atom or a phosphorus atom, n is an integer of 1 or more, and substituents of R.sub.1 to R.sub.20 substituted on carbon atoms linking two ring structures from each other are not present.

2. The plastic substrate according to claim 1, wherein a transmittance is 80% or more for light having at least a wavelength in the visible light range.

3. The plastic substrate according to claim 1, wherein a thermal expansion coefficient is in a range of 10 ppm/? C. to 50 ppm/? C.

4. The plastic substrate according to claim 1, wherein a refractive index is 1.5 or more for light having a wavelength of 550 nm or 633 nm.

5. The plastic substrate according to claim 1, wherein the scattering component is scattering particles having an average particle diameter within a range of 150 nm to 300 nm.

6. The plastic substrate according to claim 1, wherein the absolute value of difference of refractive indices in the polymeric binder and the scattering component is in a range of 0.5 to 1.2.

7. The plastic substrate according to claim 1, wherein the scattering component comprises one or more selected from the group consisting of TiO.sub.2, HfO.sub.2, BaTiO.sub.3, SnO.sub.2, ZrO.sub.2, ZnO, Al.sub.2O.sub.3, and SiO.sub.2.

8. The plastic substrate according to claim 1, showing the haze within a range of 5% to 80% in a state comprising no haze inducing element other than the scattering component of the supporting layer.

9. The plastic substrate according to claim 1, wherein the supporting layer has a surface roughness (Ra) within a range of 0.1 nm to 30 nm, measured in a region of at least 20 ?m?20 ?m.

10. The plastic substrate according to claim 1, further forming a barrier layer having a refractive index of 1.5 or more for light having a wavelength of 550 nm or 633 nm on one or both sides of the supporting layer.

11. The plastic substrate according to claim 10, further comprising a buffer layer formed between the barrier layer and the support layer.

12. The plastic substrate according to claim 1, further comprising a plane layer having a refractive index of 1.5 or more for light having a wavelength of 550 nm or 633 nm.

13. The plastic substrate according to claim 1, further comprising a carrier substrate attached to one or both sides of the supporting layer.

14. A method for producing the plastic substrate of claim 1, comprising forming a layer having a thickness of 10 ?m to 130 ?m by using a composition comprising a polymeric binder precursor and a scattering component in a ratio within a range of 0.05% by weight to 3.75% by weight relative to 100% by weight of said polymeric binder precursor, and converting said polymeric binder precursor to the polymeric binder in said layer, wherein the polymeric binder precursor comprises a repeating unit of Formula 2 below: ##STR00004## wherein, L is a single bond, an alkylene group, an alkylidene group, an alkynylene group, an arylene group, an alkenylene group, S, S(?O), S(?O).sub.2 or SS, R.sub.1 to R.sub.20 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group or a functional group comprising a halogen atom, a sulfur atom or a phosphorus atom, n is an integer of 1 or more, and substituents of R.sub.1 to R.sub.20 substituted on carbon atoms linking two ring structures from each other are not present.

15. An organic electronic device comprising the plastic substrate of claim 1; a first electrode layer formed on said substrate; an organic layer formed said first electrode layer and a second electrode layer formed on said organic layer.

16. The organic electronic device according to claim 15, wherein the organic layer comprises a light emitting layer.

17. A display light source comprising the organic electronic device of claim 15.

18. A lighting apparatus comprising the organic electronic device of claim 15.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1 to 3 show exemplary plastic substrates.

(2) FIGS. 4 and 5 are diagrams illustrating exemplary organic electronic devices.

(3) FIG. 6 shows an SEM cross-sectional image of a plastic substrate of Example 1.

(4) FIG. 7 shows optical microscopic surface images of dark field mode in plastic substrates of Example 4 and Comparative Examples 5 and 6 (scale bar: 20 ?m).

(5) FIG. 8 shows SEM surface images of plastic substrates of Example 4 and Comparative Examples 5 and 6.

(6) FIG. 9 is a graph showing transmittances in the visible light range of plastic substrates and absolute quantum efficiencies of organic light emitting devices.

MODE FOR INVENTION

(7) Hereinafter, the substrate will be more specifically described through Examples according to the present application, but the scope of the present application is not restricted by Examples set forth below.

(8) 1. Measurement of Transmittance in Plastic Substrate

(9) The transmittance of the plastic substrate was measured using an integrating sphere. More specifically, if the integrating sphere brightness at a state to switch-on the self-absorption correction lamp in the integrating sphere is referred to as L.sub.0, the integrating sphere brightness when the sample to be measured has been placed at the center in the integrating sphere is referred to as Ls, and the integrating sphere brightness when a perfect absorber having the same size as the sample has been placed at the center in the integrating sphere is referred to as L.sub.d, it is possible to calculate the transmittance of the plastic substrate with Equation 4 below.
Substrate transmittance (%)=(Ls?L.sub.D)/(L.sub.0?L.sub.D)?100[Equation 4]

(10) 2. Measurement of Haze in Plastic Substrate

(11) The haze of the plastic substrate was measured using a D65 light source by HM-150 system from MURAKAMI Co., Ltd.

(12) 3. Measurement of Surface Roughness in Plastic Substrate

(13) The surface roughness of the plastic substrate was measured using AFM (atomic force microscope) equipment, for example, NS4 D3100 DEN P-4 Rev. A equipment from Digital Instrument Inc. by non-contact (vibrating) method.

(14) 4. Measurement of Absolute Quantum Efficiency in Organic Electronic Devices

(15) The absolute quantum efficiency of the organic light emitting device was measured by an integrating hemisphere device from OTSUKA Company.

Example 1

(16) Preparation of Plastic Substrate

(17) A plastic substrate having a supporting layer was prepared by using a glass substrate as a carrier substrate. Specifically, a coating liquid was prepared by mixing TiO.sub.2 (a refractive index for light having a wavelength of 633 nm: 2.7) as a scattering component with a polymeric liquid of polyamic acid (polyimide precursor), synthesized from 3,3,4,4-biphenyl tetracarboxylic acid dianhydride and 2,2-bis(trifluoromethyl)-4,4-diaminobiphenyl as monomers in a known manner, in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 0.1% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:0.1 weight ratio).

(18) Subsequently the coating liquid was coated on the glass substrate in a range that the finally prepared supporting layer could have a thickness of about 30 ?m and then subjected to imidization to prepare the plastic substrate, in which the refractive index for light having a wavelength of 633 nm is about 1.6, having the supporting layer that the scattering component is dispersed in polyimide.

(19) The transmittance of the manufactured plastic substrate was about 88%, and the haze was about 5%.

(20) Production of Organic Electronic Device

(21) A hole injection electrode layer comprising ITO (Indium Tin Oxide) was formed on the prepared plastic substrate by the known sputtering method. Continuously, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and an electron injection electrode layer were formed using the know materials and methods. Then the above structure was sealed with a glass can to prepare an organic electronic device.

Example 2

(22) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 0.5% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:0.5 weight ratio).

(23) The transmittance of the manufactured plastic substrate was about 84%, and the haze was about 26%.

Example 3

(24) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 1% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:1 weight ratio).

(25) The transmittance of the manufactured plastic substrate was about 81%, and the haze was about 32%.

Example 4

(26) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 0.5% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:0.5 weight ratio), and the coating liquid was coated on the glass substrate in a range that the finally prepared supporting layer could have a thickness of about 14 ?m.

(27) The haze of the manufactured plastic substrate was about 33%. FIG. 7 (a) and FIG. 8 (a) show optical microscopic surface images (dark field mode) and SEM surface images of the prepared plastic substrate, respectively.

Comparative Example 1

(28) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, it was changed to include no scattering particle in the polymeric liquid of polyamic acid.

(29) The transmittance of the manufactured plastic substrate was about 94%, and the haze was about 1%.

Comparative Example 2

(30) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 5% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:5 weight ratio).

(31) The transmittance of the manufactured plastic substrate was about 78%, and the haze was about 65%.

Comparative Example 3

(32) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 10% by weight relative to 100% by weight of polyimide (polyamic acid:scattering component=100:10 weight ratio).

(33) The transmittance of the manufactured plastic substrate was about 72%, and the haze was about 84%.

Comparative Example 4

(34) The plastic substrate and the organic electronic device were prepared by performing the same method as Example 1 except that in preparing the plastic substrate, the coating liquid was prepared by mixing to polyimide subjected to imidization with adding no scattering particle to the polymeric liquid of polyamic acid in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 2% by weight relative to 100% by weight of polyimide (polyimide:scattering component=100:2 weight ratio).

(35) Comparative Example 4 was prepared in such a way that the content ratio of the scattering component was higher than Example 3, but the scattering component was added lastly after completing polymerization of polyamic acid, whereby the aggregation phenomenon of the scattering component did not secure the stable dispersibility in the polymide, and thus the locally high haze was expressed. As a result of measuring the haze, Comparative Example 4 did not exhibit haze characteristics suitable to the light extraction efficiency, and it was confirmed to locally show about 50% or more of haze.

Comparative Example 5

(36) The plastic substrate and the organic electronic device were prepared by performing the same method as Comparative Example 4 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 0.5% by weight relative to 100% by weight of polyimide (polyimide:scattering component=100:0.5 weight ratio), and the coating liquid was coated on the glass substrate in a range that the finally prepared supporting layer could have a thickness of about 10 ?m.

(37) The haze of the manufactured plastic substrate was about 3%. FIG. 7 (b) and FIG. 8 (b) show optical microscopic surface images (dark field mode) and SEM surface images of the prepared plastic substrate, respectively.

Comparative Example 6

(38) The plastic substrate and the organic electronic device were prepared by performing the same method as Comparative Example 4 except that in preparing the plastic substrate, the coating liquid was prepared by mixing in an amount that in the finally prepared supporting layer the content ratio of the scattering component could be about 20% by weight relative to 100% by weight of polyimide (polyimide:scattering component=100:20 weight ratio), and the coating liquid was coated on the glass substrate in a range that the finally prepared supporting layer could have a thickness of about 2 ?m.

(39) The haze of the manufactured plastic substrate was about 51%. FIG. 7 (c) and FIG. 8 (c) show optical microscopic surface images (dark field mode) and SEM surface images of the prepared plastic substrate, respectively.

(40) Characteristic Comparison of Examples 1-3 and Comparative Examples 1-3

(41) The contents of the scattering component, haze and transmittance in plastic substrates of Examples 1 to 3 and Comparative Examples 1 to 3 were arranged in Table 1 below, absolute quantum efficiencies of Examples 1 to 3 and Comparative Examples 1 to 3 were measured and shown in Table 1 below and FIG. 9.

(42) TABLE-US-00001 TABLE 1 C. C. C. Ex. Example Example Example Ex. Ex. 1 1 2 3 2 3 Scattering particle 0 0.1 0.5 1 5 10 content (% by weight) Haze (%) 1 5 26 32 65 84 Transmittance (%) 94 88 84 81 78 72 Absolute quantum 44 51 54 53 42 38 efficiency (%) (C. Ex.: Comparative Example)

DESCRIPTION OF REFERENCE NUMERALS

(43) 1: plastic substrate 101: supporting layer 1011: polymeric binder 1012: scattering component 301: plane layer 401: Transparent electrode layer 402: organic layer 403: second electrode layer, 404: can type sealing structure 501: film type sealing structure 502: second substrate