# US 2010/0167012 A1 · Multi-layer film for use as a solar cell substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0167012 A1 - Document ID: US20100167012A1 - Status: Published application - Kind: A1 - Application number: 12/600,927 - Filed: 2008-05-23 - Published: 2010-07-01 - Earliest claimed: 2007-05-23 - Assignees: Teijin Dupont Films Japan Limited - Inventors: Rei Nishio; Koji Kubo - Web page: https://patentgrep.com/patent/US20100167012A1 ## CPC - H10F 77/315: {the coatings being antireflective or having enhancing optical properties} - B32B 27/08: of synthetic resin - B32B 27/18: characterised by the use of special additives - B32B 27/285: {comprising polyethers} - B32B 27/286: {comprising polysulphones; polysulfides} - B32B 27/288: {comprising polyketones} - B32B 27/34: comprising polyamides - B32B 27/36: comprising polyesters - H10F 77/169: Thin semiconductor films on metallic or insulating substrates - B32B 2250/24: All layers being polymeric - B32B 2250/42: Alternating layers, e.g. ABAB(C), AABBAABB(C) - B32B 2264/0214: Particles made of materials belonging to B32B27/00 - B32B 2264/0235: Aromatic vinyl resin, e.g. styrenic (co)polymers - B32B 2264/10: Inorganic particles - B32B 2264/102: Oxide or hydroxide - B32B 2264/104: Oxysalt, e.g. carbonate, sulfate, phosphate or nitrate particles - B32B 2264/12: Mixture of at least two particles made of different materials - B32B 2307/306: Resistant to heat - B32B 2307/308: Heat stability - B32B 2307/40: having particular optical properties - B32B 2307/418: Refractive - B32B 2307/50: having particular mechanical properties - B32B 2307/514: Oriented - B32B 2307/538: Roughness - B32B 2307/546: Flexural strength; Flexion stiffness - B32B 2307/712: Weather resistant - B32B 2307/7242: Non-permeable - B32B 2307/7265: Non-permeable - B32B 2307/734: Dimensional stability - B32B 2457/12: Photovoltaic modules - Y02E 10/50: Photovoltaic [PV] energy - Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A multi-layer film for use as a solar cell substrate, consisting of a supporting layer (s) and a scattering layer (s), wherein the supporting layer comprises a thermoplastic crystalline resin, the scattering layer comprises a thermoplastic crystalline resin and particles having a different refractive index from the refractive index of the thermoplastic crystalline resin, the content of the particles in the scattering layer is 0.05 to 20 vol % based on the volume of the scattering layer, the absolute value of the difference between the refractive index of the particles contained in the scattering layer and the refractive index of the thermoplastic crystalline resin in the scattering layer is 0.01 to 1.00, the both surfaces of the multi-layer film have a center line average surface roughness Ra of not more than 50 nm, and the multi-layer film has a total light transmittance Tt of not less than 80% and a haze ratio of not less than 8%. ## Claims ### Claim 1 A multi-layer film for use as a solar cell substrate, consisting of a supporting layer(s) and a scattering layer(s), wherein the supporting layer comprises a thermoplastic crystalline resin, the scattering layer comprises a thermoplastic crystalline resin and particles having a different refractive index from the refractive index of the thermoplastic crystalline resin, the content of the particles in the scattering layer is 0.05 to 20 vol % based on the volume of the scattering layer, the absolute value of the difference between the refractive index of the particles contained in the scattering layer and the refractive index of the thermoplastic crystalline resin in the scattering layer is 0.01 to 1.00, the both surfaces of the multi-layer film have a center line average surface roughness Ra of not more than 50 nm, and the multi-layer film has a total light transmittance Tt of not less than 80% and a haze ratio of not less than 8%. ### Claim 2 (depends on 1) The multi-layer film for use as a solar cell substrate according to claim 1, wherein the thermoplastic crystalline resins of the supporting layer and the scattering layer are a thermoplastic polyester. ### Claim 3 (depends on 2) The multi-layer film for use as a solar cell substrate according to claim 2, wherein the thermoplastic polyester of the supporting layer and the scattering layer is a polyester comprising an ethylene-2,6-naphthalene dicarboxylate component as the main recurring unit. ### Claim 4 (depends on 3) The multi-layer film for use as a solar cell substrate according to claim 3, wherein the particles are silica particles or melamine resin particles. ### Claim 5 (depends on 1) The multi-layer film for use as a solar cell substrate according to claim 1, wherein the center line average surface roughness Ra of at least one surface of the multi-layer film is not more than 30 nm. ### Claim 6 (depends on 1) The multi-layer film for use as a solar cell substrate according to claim 1, wherein the multi-layer film has a double-layer structure consisting of one supporting layer and one scattering layer, the center line average surface roughness Ra of the supporting layer side surface of the multi-layer film is not more than 30 nm, and the center line average surface roughness Ra of the scattering layer side surface is not more than 50 nm. ### Claim 7 (depends on 1) The multi-layer film for use as a solar cell substrate according to claim 1, wherein the multi-layer film has a three-layer structure consisting of a supporting layer, a scattering layer and a supporting layer in this order, and the center line average surface roughnesses Ra of the both surfaces of the multi-layer film are not more than 30 nm. ### Claim 8 (depends on 1) The multi-layer film for use as a solar cell substrate according to claim 1, which is used as a substrate for flexible type thin film solar cells. ### Claim 9 (depends on 2) The multi-layer film for use as a solar cell substrate according to claim 2, wherein the multi-layer film has a double-layer structure consisting of one supporting layer and one scattering layer, the center line average surface roughness Ra of the supporting layer side surface of the multi-layer film is not more than 30 nm, and the center line average surface roughness Ra of the scattering layer side surface is not more than 50 nm. ### Claim 10 (depends on 3) The multi-layer film for use as a solar cell substrate according to claim 3, wherein the multi-layer film has a double-layer structure consisting of one supporting layer and one scattering layer, the center line average surface roughness Ra of the supporting layer side surface of the multi-layer film is not more than 30 nm, and the center line average surface roughness Ra of the scattering layer side surface is not more than 50 nm. ### Claim 11 (depends on 4) The multi-layer film for use as a solar cell substrate according to claim 4, wherein the multi-layer film has a double-layer structure consisting of one supporting layer and one scattering layer, the center line average surface roughness Ra of the supporting layer side surface of the multi-layer film is not more than 30 nm, and the center line average surface roughness Ra of the scattering layer side surface is not more than 50 nm. ### Claim 12 (depends on 5) The multi-layer film for use as a solar cell substrate according to claim 5, wherein the multi-layer film has a double-layer structure consisting of one supporting layer and one scattering layer, the center line average surface roughness Ra of the supporting layer side surface of the multi-layer film is not more than 30 nm, and the center line average surface roughness Ra of the scattering layer side surface is not more than 50 nm. ### Claim 13 (depends on 2) The multi-layer film for use as a solar cell substrate according to claim 2, wherein the multi-layer film has a three-layer structure consisting of a supporting layer, a scattering layer and a supporting layer in this order, and the center line average surface roughnesses Ra of the both surfaces of the multi-layer film are not more than 30 nm. ### Claim 14 (depends on 3) The multi-layer film for use as a solar cell substrate according to claim 3, wherein the multi-layer film has a three-layer structure consisting of a supporting layer, a scattering layer and a supporting layer in this order, and the center line average surface roughnesses Ra of the both surfaces of the multi-layer film are not more than 30 nm. ### Claim 15 (depends on 4) The multi-layer film for use as a solar cell substrate according to claim 4, wherein the multi-layer film has a three-layer structure consisting of a supporting layer, a scattering layer and a supporting layer in this order, and the center line average surface roughnesses Ra of the both surfaces of the multi-layer film are not more than 30 nm. ### Claim 16 (depends on 5) The multi-layer film for use as a solar cell substrate according to claim 5, wherein the multi-layer film has a three-layer structure consisting of a supporting layer, a scattering layer and a supporting layer in this order, and the center line average surface roughnesses Ra of the both surfaces of the multi-layer film are not more than 30 nm. ### Claim 17 (depends on 2) The multi-layer film for use as a solar cell substrate according to claim 2, which is used as a substrate for flexible type thin film solar cells. ### Claim 18 (depends on 3) The multi-layer film for use as a solar cell substrate according to claim 3, which is used as a substrate for flexible type thin film solar cells. ### Claim 19 (depends on 4) The multi-layer film for use as a solar cell substrate according to claim 4, which is used as a substrate for flexible type thin film solar cells. ### Claim 20 (depends on 5) The multi-layer film for use as a solar cell substrate according to claim 5, which is used as a substrate for flexible type thin film solar cells.