Illumination device, method for driving the illumination device and display including the illumination device
AssigneeSharp Kabushiki Kaisha
InventorsHiroshi Torihara, Takayoshi Tanabe, Kenichi Ukai, Nobuyuki Takahashi
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Abstract
An illumination device includes a cold cathode fluorescent tube having a heat capacity of 0.035 Wsec/.degree. C. or less per unit length (1 cm) of a glass tube of a fluorescent section of the cold cathode fluorescent tube. The illumination device has a superior operation characteristic at a low temperature. The device is driven by a method and is implemented in a display device.
Claims23
An illumination device, comprising a cold cathode fluorescent tube having a heat capacity of about 0.035 Wsec/.degree. C. or less per unit length (1 cm) of a glass tube of a fluorescent section of the cold cathode fluorescent tube, wherein about 95% or more of a total surface area of the fluorescent section of the cold cathode fluorescent tube is exposed to air, and wherein about 50% or more of light emitted from the cold cathode fluorescent tube is utilized for illumination.
An illumination device including a cold cathode fluorescent tube, comprising:
- a temperature sensor thermally coupled to the cold cathode fluorescent tube, wherein
- luminance is adjusted by controlling power supplied to the cold cathode fluorescent tube based on a sensed-temperature signal from the temperature sensor and by approximating a relation between luminance and a temperature sensed by the temperature sensor by one of expressions of a first order which are provided for respective temperature ranges, and controlling a duty ratio of the power supplied to the cold cathode fluorescent tube based on the expression, respectively.
An illumination device including a cold cathode fluorescent tube, comprising:
- a temperature sensor thermally coupled to the cold cathode fluorescent tube, wherein
- luminance is adjusted by controlling power supplied to the cold cathode fluorescent tube based on a sensed-temperature signal from the temperature sensor and by approximating a relation between luminance and a temperature sensed by the temperature sensor by a polynomial, and controlling a duty ratio of the power supplied to the cold cathode fluorescent tube based on the polynomial.
Dependencies are inferred from the claim text.