| 摘要 |
PROBLEM TO BE SOLVED: To reduce light beam shielding quantity due to a heating source, to prevent thermorunaway, by providing a self-heating adjusting heating source on the periphery of a light source, and a light reflecting layer between both these sides. SOLUTION: The heating composition of a self-heating adjusting heating source 7 has a thermoplastic resin and a conductive particle, and is equipped with a positive temperature coefficient characteristic, wherein a resistance value increases with the rise of temperature. Light, radiated from a low-pressure mercury lamp 6, radiated from a low-pressure mercury lamp 6, is sent directly to a light leading plate 5, or is sent to the light leading plate 5 after reflected by light reflecting layers 8 and 9, moreover is incident into a liquid crystal panel 3 via the light leading plate 5. When the core wire 11 of the heating source 7 is electrified to heat the mercury lamp 6 by the heating source 7, a resistance value is restrained relatively low, until temperature wherein the luminous efficacy of the mercury lamp 6 becomes maximum, consequently, heating quantity is increased; and after temperature, wherein luminous efficacy becomes maximum, is passed, the resistance value rises, thereby restraining the heating quantity. |
