Light refection sheet, process for producing the same and molding thereof

• Main Author: FUNAKI KEISUKE,KOGURE MASAMI,AKAMINE HIROSHI,KAWATO HIROSHI
• Format: Patent
• Language: English
• Published: 25.10.2006
• Subjects: BLASTING; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; HEATING; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; LIGHTING; MECHANICAL ENGINEERING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICAL LOGIC ELEMENTS; OPTICS; PERFORMING OPERATIONS; PHYSICS; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TRANSPORTING; WEAPONS

There is provided light reflection sheet (I) of 0.4 to 2 mm thickness comprised of a PC resin composition containing titanium oxide, which sheet exhibits a light reflectance of 98% or higher and a light transmittance of less than 1%. The light reflection sheet (I) excels in flame retardance and light reflection characteristics. There is further provided light reflection sheet (II) comprising a base sheet of 0.4 to 2 mm thickness comprised of a PC resin composition, the PC resin composition comprising a combination of 85 to 60 mass% of PC polymer (A) and 15 to 40 mass% of titanium oxide (B), and, superimposed on at least one major surface of the base sheet, a lightproof layer of 0.5 to 20 mum thickness capable of cutting or absorbing ultraviolet radiation. The light reflection sheet (II) suppresses yellowing and drop of reflection characteristics after prolonged use. There is still further provided light reflection sheet (III) comprising the same base sheet as employed in the light reflection sheet (II) and, superimposed on at least one major surface thereof, a light diffusion layer of 0.5 to 20 mum thickness capable of light diffuse reflection. The light reflection sheet exhibits enhanced light diffuse reflection characteristics and when used as a perpendicular transmission type liquid crystal backlight, can provide a liquid crystal viewing plane of reduced luminance irregularity.