Patent ID: 7712939

Claim:
A backlight unit, comprising: a light source generating a light; a light guide panel for converting the light being incident to a side surface into a surface light progressing to a upper surface of the light guide panel; a reflection plate located at a lower part of the light guide panel that reflects the light; optical sheets for controlling a diffusion and progress direction of the light from the light source and passing through the light guide panel; a temperature sensor for sensing a temperature of the light source at a location which is suitable for measuring the temperature of the light source; a housing encompassing the light source except for a part of the light source opposing the side surface of the light guide panel and having a specular surface in the inner surface thereof to reflect the light from the light source to the side surface of the light guide panel; a peltier device for increasing or decreasing the temperature of the light source and being attached to the whole of the external surface of the housing; and a controller for controlling the peltier device so as for the temperature sensed at the temperature sensor to be always kept at a fixed level in correspondence to an output of the temperature sensor, wherein the output terminal of the temperature sensor is connected to the controller and the peltier device is connected to the controller a support main for supporting the backlight unit and a cover bottom for encompassing a bottom and a side surfaces of one side of the support main wherein the peltier device using a ceramic substrate; and, wherein an internal side surface of the peltier device contacts the external surface of the housing and an external side surface of the peltier device contacts an internal surface of the cover bottom.