WO2007145390A1

WO2007145390A1 - Method of manufacturing polymer light-emitting sheet

Info

Publication number: WO2007145390A1
Application number: PCT/KR2006/002443
Authority: WO
Inventors: Doo-Ill Kim
Original assignee: Doo-Ill Kim
Priority date: 2006-06-12
Filing date: 2006-06-23
Publication date: 2007-12-21
Also published as: KR100657763B1

Abstract

Disclosed therein is a method for manufacturing a polymer light-emitting sheet. The method includes the steps of a) manufacturing a PET film by extruding material for a conductive mesh layer and conductive polymer material; b) forming a fluorescent layer having a predetermined thickness on the polymer layer by coating phosphor substance on the conductive polymer layer of the PET film one or more times; c) causing light diffusion and reflection for the fluorescent layer, and forming a dielectric layer by coating dielectric substance with uniform thickness two or more times; and d) forming a rear electrode layer by performing filming and plating on the dielectric layer.

Description

METHOD OF MANUFACTURING POLYMER LIGHT- EMITTING SHEET

Technical Field

[1] The present invention relates generally to a method of manufacturing a polymer light-emitting sheet and, more particularly, to a method of manufacturing a polymer light-emitting sheet which sets optimal viscosity and dry conditions for a fluorescent layer and a dielectric layer which constitute the polymer light-emitting sheet, thereby enhancing productivity upon production of the polymer light-emitting sheet having a large size and the light emitting luminance of the polymer light-emitting sheet. Background Art

[2] Generally, billboards catch the customers' eyes and then provide information which advertisers desire to advertise. Therefore, unique characters, figures, or colors are exhibited, thereby attracting customers' attentions. Conventionally, desired characters and figures are generally engraved and painted in an acrylic plate or a synthetic resin sheet, but visibility dramatically decreases at night. Recently, backlights, such as neon lamps, fluorescent lamps, and Cold Cathode Fluorescent Lamps (CCFLs) are used, so that advertisement content is visible even at night.

[3] Furthermore, recently, an electro-luminescence (EL) sheet has been developed.

Such an electro-luminescence element is a planar illuminant in which a fluorescent layer and a dielectric layer are sequentially formed between a transparent conductive film and a rear electrode, thereby forming a light-emitting layer. A protective film is inserted between the dielectric layer and the rear electrode to protect a light-emitting sheet. When alternating current is applied to the light-emitting layer, light emitted from the fluorescent layer is radiated through the transparent conductive film. Such an electro-luminescence sheet has an operation frequency within a range of 400 Hz to 2,000 Hz at an operation temperature within a range of -35⁰C to 7O⁰C.

[4] The above-described electro-luminescence element is classified into an ELD and an

LEP. The ELD is formed of a polyester transparent film which is one of polymer films, the flexibility, permeability and heat resistant of which are excellent, a front electrode layer which is applied on the rear surface of the polyester transparent film, and made of Indium Tin Oxide (ITO) having conductivity and good light permeability, a fluorescent layer formed on the rear surface of the front electrode layer, an organic dielectric layer formed on the rear surface of the fluorescent layer, a rear electrode layer formed on the rear surface of the organic dielectric layer, and a protection layer formed on the rear surface of the rear electrode layer. [5] Furthermore, the ELD is operated so as to apply predetermined voltage to the front electrode layer and the rear electrode layer, thereby emitting the phosphor of a specific pixel. In detail, the polyester transparent film is extruded to have a thickness within a range of 50 to 150 D to be suitable for it's purpose, and one side surface thereof is discharged. In order to resolve the problem of shrinking due to thermal stress during a thermal process, required upon production of electro-luminescence elements, the thermal process is performed for about 30 minutes at about 150⁰C.

[6] The front electrode layer is formed by sputtering ITO-tartar on the discharged surface thereof to have a thickness of dozens to thousands A in consideration of the light permeability. In this case, it is preferred that the planar resistance of the ITO- tartar be set to about dozens to hundreds Ω/squ. The organic dielectric layer is formed by melting polyester resinous polymer resin in a solvent, manufacturing a paste using plasticizer, printing it to have a thickness within a range of about 30 to 70 D, and drying it for about 30 minutes at a temperature within a range of 100 to 140⁰C. In this case, it is preferable that the permeability of the organic dielectric layer be set to about 70 to 80%.

[7] Meanwhile, the Polymer Light Emitting (PLE) sheet is formed of a fluorescent layer and a dielectric layer, a rear electrode layer and a specific synthetic resin layer as illustrated in FIG. 1. The fluorescent layer is a fluoride binder, the permittivity of which is more than 30 D, and the durability and moisture resistance of which are excellent, and has characteristics in that adhesive strength to the PLE film and luminance are high. The above-described PLE sheet is formed of the conductive polymer layer and the conductive mesh layer, and is designed to have a surface resistance of 10 Ωm . Furthermore, ability of blocking ultraviolet rays and light diffusion thereof are high, thereby being applied for general-purpose.

[8] Furthermore, the dielectric layer has excellent light diffusion and reflection, and is designed to have permittivity of more than 30 D. The rear electrode is processed into an Al or Cu film, can be enlarged, and has a resistance of about lOΩm². The protective layer can protect entire elements against UV or IR, and is processed into a flexible film having high moisture resistance. Furthermore, such a LEP has luminance that is higher than that of ELD, and the manufacturing cost thereof is lower than that of ELD, thereby the usage range being wide. Therefore, development investment by manufacturers for the mass production of the LEP has increased.

[9] However, the above-described LEP has many advantages and the mass production thereof is easy, but there are problems in that the quality thereof varies depending on manufacture conditions during mass production, thereby not satisfying expectation. That is, during a process of manufacturing respective layers to implement a fluorescent layer, a dielectric layer, a rear electron layer and a specific synthetic resin layer con- stituting the LEP, luminance varies depending on the thickness, viscosity, and dry time of layers.

Disclosure of Invention

Technical Problem

[10] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method of manufacturing a polymer light-emitting sheet which stably increases the manufactured area of the polymer organic light-emitting sheet.

[11] Another object of the present invention is to provide a method of manufacturing a polymer light-emitting sheet in which the phosphor, dielectric substance and silver layer of the polymer light-emitting display sheet maintain optimal viscosity in a set environment, thereby minimizing the deformation of the sheet and preventing change in light emitting luminance.

[12] Still another object of the present invention is to provide a method of manufacturing a polymer light-emitting sheet, which uses dry and coating conditions for uniformly standardizing the phosphor, dielectric substance and silver layer of the polymer light- emitting display sheet, thereby enhancing light-emitting luminance. Technical Solution

[13] In order to accomplish the above objects, the present invention provides a method for manufacturing a polymer light-emitting sheet, including the steps of a) manufacturing a PET film by extruding material for a conductive mesh layer and conductive polymer material; b) forming a fluorescent layer having a predetermined thickness on the polymer layer by coating phosphor substance on the conductive polymer layer of the PET film one or more times; c) causing light diffusion and reflection for the fluorescent layer, and forming a dielectric layer by coating dielectric substance with uniform thickness two or more times; and d) forming a rear electrode layer by performing filming and plating on the dielectric layer.

[14] Preferably, the PET film has a thickness within a range of 70 D to 80 D.

[15] Preferably, the conductive mesh layer of the step a) is a mesh-shaped adherent film made of conductive material, such as aluminum or copper, and has a density within a range of screen 75 mesh to 85 mesh.

[16] Preferably, the conductive polymer layer is made of solid conductive polymer aluminum (AL O ).

[17] Preferably, the conductive polymer layer is made of one of Polyacetylene, P- phenylene, Polythiophence, ethylendioxythiophene, Polypyrrole, P-phenylene vinylene, thienylene vinylene, Polyaniline, Polysothianaphthence, P-Phenylene sulfide.

[18] Preferably, the conductive mesh layer and the conductive polymer layer are man- ufactured as two films which are conductive to each other and are extruded, and an internal resistance of the PET film maintains a range of 100 to 125 Ω. [19] Preferably, the fluorescent layer is made of one or more of petroleum, flint glass, and white gold tricyanide. [20] Preferably, the fluorescent layer is cured by adding lubricant (silver, copper, manganese, lead, or the like) to zinc sulphide (ZnS) or a mixture of ZnS and cadmium sulfide. [21] Preferably, the fluorescent layer is made of phosphor substance having viscosity

(poises) within a range of 3500 pes to 4500 pes. [22] Preferably, the fluorescent layer is dried at a temperature within a range of 135⁰C to

145⁰C, preferably, 14O⁰C for time within a range of 4 to 6 minutes after the phosphor has been applied throughout the PET with set viscosity. [23] Preferably, the fluorescent layer is a fluoride binder, permittivity of which is more than 30 D. [24] Preferably, any one dielectric substance of Polyester, Polypropylene, and

Polypropylene-sulfide is used for the dielectric layer, and the dielectric substance has viscosity (poises) of 12000 pes, and the dielectric layer is formed by performing coating to have a thickness within a range of 20 to 25 D two or more times. [25] Preferably, the dielectric substance is dried at 135⁰C to 145⁰C for time within a range of four to six minutes and the dielectric layer has permittivity of more than 30 D and is applied to the fluorescent layer in a solid form (film). [26] Preferably, the rear electron layer is processed into an Al or Cu film to have a resistance of about 10 Ωm², and is plated using any one of electric zinc treatment, electric copper plating, electric nickel plating, chrome plating, silver plating, gold plating, or electrodeless nickel plating. [27] Preferably, the rear electron layer is applied to have viscosity of 10,000 cps and dried at a temperature within a range of 135⁰C to 145⁰C, for time within a range of 4 to

6 minutes. [28] More preferably, the method further includes the step of e) coating silver over the

PET film before performance of the step b), wherein the step b) is performed after the step e), and performed on an upper surface of the conductive polymer layer on which silver is applied.

Brief Description of the Drawings [29] FIG. 1 is a diagram illustrating the structure of a polymer light-emitting sheet according to an embodiment of the present invention;

[30] FIG. 2 is a flowchart illustrating a process of manufacturing the polymer light- emitting sheet shown in FIG. 1 ; and [31] FIGS. 3 to 5 are graphs illustrating the experiment results of the polymer light- emitting sheet manufactured according to the embodiment of the present invention. Mode for the Invention

[32] Preferred embodiments of the present invention are described in detail with reference to the accompanying drawings.

[33] FIG. 1 is a diagram illustrating the structure of a polymer light-emitting sheet manufactured using a method of manufacturing a polymer light-emitting sheet according to an embodiment of the present invention.

[34] Referring to FIG. 1, the structure of the polymer light-emitting sheet includes a PET which is composed of a conductive mesh layer 103 and a conductive polymer layer 105, a fluorescent layer 107 which is attached to the PET as the lower layer thereof and has permittivity of more than 30 D, the durability and moisture resistance of which are excellent, a dielectric layer 109 which is constructed as the lower layer of the fluorescent layer 107, has excellent light diffusion and reflection, and is designed to have permittivity of more than 30 D, and a rear electrode layer 111 which is constructed as the lower layer of the dielectric layer 109, is processed into an Al or Cu film, and has a resistance of about 10 Ωm .

[35] Alternatively, a silver layer 105- 1 may be located between the conductive polymer layer 105 and the fluorescent layer 107 as indicated by a dotted line in FIG. 1.

[36] Furthermore, in the polymer organic light-emitting sheet, specific synthetic resin layers 113 and 101 are respectively formed as the lower layer of the rear electrode layer 111 and the upper layer of the conductive mesh layer 103. The specific synthetic resin layers 113 and 101 provide the tension of the sheet, protect the sheet against infrared rays and ultraviolet rays, and are processed into flexible films each having a high moisture resistance. Therefore, after the fluorescent layer 107 and the dielectric layer 109 have been sequentially applied as the lower layers of the PET, and the rear electrode layer 111 has been constructed, the specific synthetic resin layers 113 and 101 are filmed.

[37] FIG. 2 is a flowchart illustrating a process of manufacturing a polymer light- emitting sheet according to an embodiment of the present invention. As illustrated in FIG. 2, the PET film is manufactured at step S201. The PET film is composed of the conductive mesh layer 103 and the conductive polymer layer 105. The PET film preferably has a thickness within a range of 70 □ to 80 D, and, more preferably, a thickness of 75 D. The conductive mesh layer 103 constituting the PET film is a mesh- shaped adherent film made of conductive material, such as aluminum or copper. A film preferably having a density within a range of screen 75 mesh to 85 mesh, and, more preferably, a density of screen 80 mesh. [38] Meanwhile, the conductive polymer layer 105 is preferably made of solid conductive polymer aluminum (AL O ). In the present invention, in addition to such solid conductive polymer aluminum (AL O ), conductive polymer, which can be used as solid electrolyte, can be used. The above-described conductive polymer may be selected from among Polyacetylene, P-phenylene, Polythiophence, ethylen- dioxythiophene, Polypyrrole, P-phenylene vinylene, thienylene vinylene, Polyaniline, Polysothianaphthence, P-Phenylene sulfide.

[39] After the conductive mesh layer 103 and the conductive polymer layer 105 have been manufactured as two films which are conductive to each other. The two films are extruded. The internal resistance of the PET film maintains 100 to 125 Ω. The extrusion of the PET film is performed such that the internal resistance is maintained through uniform pressure, and the PET film is extruded to have a thickness of 75 D. After the PET film has been manufactured, the fluorescent layer 107 is applied on one side surface of the PET film at step S203.

[40] The fluorescent layer 107 may be made of various materials, such as petroleum, flint glass, or white gold tricyanide, but can be cured by adding a very small amount of lubricant (silver, copper, manganese, lead, or the like) to Zinc sulphide (ZnS) or the mixture of ZnS and cadmium sulfide. In this case, the curing temperature is about 1,000⁰C. Of cause, phosphate material (Ca2(PO4)2-CaF2:Sb, etc.), silicate material or pure tungstate(CaWO4 or MgW04) material may be used, and the intensity of an emitting color and the decrement type of light are different depending on the compound of each of the materials and the lubricant.

[41] As described above, phosphor used for the fluorescent layer 107 is applied on the

PET film while the viscosity (poises) thereof is maintained within a range of 3500 pes to 4500 pes. The viscosity of the phosphor is related to the operation voltage of the polymer organic light-emitting sheet. When the viscosity is high or low, change in an operation frequency of 800 KHz which operates the sheet is inevitable. Furthermore, since the viscosity of the phosphor affects light emitting luminance, the viscosity corresponding to the set operation voltage and frequency is indispensable. In the present invention, the viscosity of phosphor is maintained to 4000 cps. The measurement of viscosity (poises) is performed at a temperature of 25⁰C using a sample, the amount of which is 350 ml, and the precision of a viscometer is below 10%.

[42] Furthermore, after the phosphor has been applied on the PET film to have set viscosity, the fluorescent layer 107 is dried at a temperature within a range of 135⁰C to 145⁰C for about four to six minutes. The dry temperature is related to the density of the applied phosphor. That is, when the dry temperature exceeds the above-described value, the dry of the phosphor is rapidly performed, so that non-uniform dryness occurs in the part of the phosphor. Furthermore, when the dry temperature is lower than the above-described value, there are problems in that dry time become elongated and the strain of a coated surface is caused.

[43] Therefore, the coating of the fluorescent layer 107 is dried at a temperature within a range of 135⁰C to 145⁰C, preferably, 14O⁰C for time within a range of 4 to 6 minutes, preferably, 5 minutes. The fluorescent layer 107 has a thick ness within a range of 45 to 50 D and the coating is performed one or more times. The fluorescent layer 107 is a fluoride binder, the permittivity of which is more than 30 D. Furthermore, not only adhesive strength to the PET film is excellent, but the durability and moisture resistance thereof are high and the light emitting luminance is high.

[44] Meanwhile, after step S201 has performed and before the process proceeds to step

S203, silver is selectively provided (or applied) on the conductive polymer layer, thereby forming the silver layer 105-1. Thereafter, the process proceeds to step S203, and the fluorescent layer 107 is formed on the silver layer 105-1 at step S201-1.

[45] Meanwhile, when the process proceeds to step S205, the fluorescent layer 107 has been applied, and then the dielectric layer 109 is applied. The dielectric layer 109 is formed by applying phosphor over the upper surface of the fluorescent layer 107. Material causing light diffusion and reflection, such as polyester, polypropylene, or polypropylene-sulfide is used for the material of the phosphor. The material of dielectric has a viscosity (Poises) of 12000 cps, and the condition for the measurement of viscosity is the use of a sample, the amount of which is 350ml, at a temperature of 25⁰C as described above. Furthermore, the coating of the dielectric layer 109 manufactured under the above-described viscosity and dry conditions has a thickness within a range of 20 to 25 D and is performed one or more times (preferably, one time). Furthermore, the coating of the dielectric layer 109 is died under a condition identical to that of the fluorescent layer 107, that is, at a temperature within a range of 135⁰C to 145⁰C, preferably, 14O⁰C for time within a range of 4 to 6 minutes, preferably, 5 minutes.

[46] The constructed dielectric layer 109 has permittivity of more than 30 D and is applied over the lower surface of the fluorescent layer 107 in a solid form (film). Furthermore, the coating of the dielectric layer 109 is applied at step S207. That is, the dielectric layer 109 is applied total two or more times (preferably, two times) to have a thickness within a range of 20 to 25 D, in which a first coating and a second coating have the same condition and the same sample.

[47] When the coating of the dielectric layer 109 has been complemented, the coating of the rear electrode layer 111 is performed. The rear electrode layer 111 is processed into an Al or Cu film, thereby enabling upper size. Furthermore, the rear electron layer 111 has a resistance of about 10 Ωm , and is applied to have viscosity of 10000 cps. Dry is performed under dry conditions, that is, at a temperature within a range of 135⁰C to 145°C, preferably, 140⁰C and for time within a range of 4 to 6 minutes, preferably, 5 minutes.

[48] The rear electrode layer 111 is for delivering power, supplied to the sheet, to the fluorescent layer 107 and the dielectric layer 109 and, if required, electric zinc treatment, electric copper plating, electric nickel plating, chrome plating, silver plating, gold plating, electrodeless nickel plating or the like may be performed. The rear electrode layer 111 is preferably applied one or more times (preferably one time) to have a thickness within a range of 5 to 10 D. Since the power supplied to the sheet is low, the coating thickness and frequency of the rear electrode layer 111 are set to be minimized without problems.

[49] The process proceeds to step S211, so that the specific synthetic resin layers 101 and 113 are provided with a sheet which has been coated with from the PET to the rear electrode layer 111. The specific synthetic resin layers 101 and 113 have a function of protecting the sheet against UV and IR, and are processed into flexible films each having high moisture resistance.

[50] Any one of many types of specific synthetic resins, such as vinyl acetate, vinyl acetate- vinyl chloride series, may be used as a specific synthetic resin, and the specific synthetic resin is made of transparent material, the thickness thereof is not limited.

[51] The above-described polymer organic light-emitting display sheet has a luminance characteristic dependent on voltage variation which is larger than that of a general ELD as illustrated in FIG. 3, and a wide frequency band may be used as illustrated in FIG. 4. Furthermore, luminance dependent on size variation is shown in FIG. 5. It can be known that there is little change in luminance dependent on area variation in the polymer organic light-emitting display sheet of the present invention. This indicates that a sheet having large size can be manufactured.

[52] As described above, in the present invention, a method of applying a PET, a fluorescent layer and a dielectric layer for manufacturing the polymer organic light- emitting display sheet provides an advantage in that the adhesive strength and luminance of the sheet can increase. At the same time, sheets having large size can be manufactured in order to enhance the value as products, and the durability and moisture resistance thereof increase.

[53] Although the specific preferred embodiment of the present invention have been illustrated and described, the present invention is not limited to the embodiment and those skilled in the art can modify it, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A method for manufacturing a polymer light-emitting sheet, comprising the steps of: a) manufacturing a PET film by extruding material for a conductive mesh layer and conductive polymer material; b) forming a fluorescent layer having a predetermined thickness on the polymer layer by coating phosphor substance on the conductive polymer layer of the PET film one or more times; c) causing light diffusion and reflection for the fluorescent layer, and forming a dielectric layer by coating dielectric substance with uniform thickness two or more times; and d) forming a rear electrode layer by performing filming and plating on the dielectric layer.

[2] The method as set forth in claim 1 , wherein the PET film has a thickness within a range of 70 D to 80 D. [3] The method as set forth in claim 1, wherein the conductive mesh layer of the step a) is a mesh-shaped adherent film made of conductive material, such as aluminum or copper, and has a density within a range of screen 75 mesh to 85 mesh. [4] The method as set forth in claim 1 , wherein the conductive polymer layer is made of solid conductive polymer aluminum (AL O ). [5] The method as set forth in claim 1, wherein the conductive polymer layer is made of one of Polyacetylene, P-phenylene, Polythiophence, ethylen- dioxythiophene, Polypyrrole, P-phenylene vinylene, thienylene vinylene,

Polyaniline, Polysothianaphthence, P-Phenylene sulfide. [6] The method as set forth in any one of claims 1 to 5, wherein the conductive mesh layer and the conductive polymer layer are manufactured as two films which are conductive to each other and are extruded, and an internal resistance of the PET film maintains a range of 100 to 125 Ω. [7] The method as set forth in claim 1, wherein the fluorescent layer is made of one or more of petroleum, flint glass, and white gold tricyanide. [8] The method as set forth in claim 1, wherein the fluorescent layer is cured by adding lubricant (silver, copper, manganese, lead, or the like) to zinc sulphide

(ZnS) or a mixture of ZnS and cadmium sulfide. [9] The method as set forth in any one of claims 1 to 8, wherein the fluorescent layer of the step b) is made of phosphor substance having viscosity (poises) within a range of 3500 pes to 4500 pes. [10] The method as set forth in claim 9, wherein the fluorescent layer is dried at a temperature within a range of 135⁰C to 145⁰C, preferably, 14O⁰C for time within a range of 4 to 6 minutes after the phosphor has been applied throughout the PET with set viscosity. [11] The method as set forth in claim 9, wherein the fluorescent layer is a fluoride binder, permittivity of which is more than 30 D. [12] The method as set forth in claim 1, wherein any one dielectric substance of

Polyester, Polypropylene, and Polypropylene-sulfide is used for the dielectric layer. [13] The method as set forth in claim 12, wherein the dielectric substance has viscosity (poises) of 12000 pes, and is applied to have a thickness within a range of 20 to 25 D two or more times. [14] The method as set forth in claim 13, wherein the dielectric substance is dried at

135⁰C to 145⁰C for time within a range of four to six minutes. [15] The method as set forth in any one of claims 1, 12 to 14, wherein the dielectric layer has permittivity of more than 30 D and is applied to the fluorescent layer in a solid form (film). [16] The method as set forth in claim 1, wherein the rear electron layer is processed into an Al or Cu film to have a resistance of about 10 Ωm . [17] The method as set forth in claim 1, wherein the rear electron layer is plated using any one of electric zinc treatment, electric copper plating, electric nickel plating, chrome plating, silver plating, gold plating, or electrodeless nickel plating. [18] The method as set forth in claim 16 or 17, wherein the rear electron layer is applied one time with a thickness within a range of 5 to 10 D. [19] The method as set forth in claim 16 or 17, wherein the rear electron layer is applied to have viscosity of 10,000 cps and dried at a temperature within a range of 135°C to 145⁰C, for time within a range of 4 to 6 minutes. [20] The method as set forth in claim any one of claims 1 to 19, further comprising the step of e) coating silver over the PET film before performance of the step b), wherein the step b) is performed after the step e), and performed on an upper surface of the conductive polymer layer on which silver is applied.