Backlight device, method of driving backlight and liquid crystal display apparatus

A backlight device having light emitting diodes of red, green and blue as a light source, the backlight device synthesizing light emitted from the light emitting diodes of each color to produce white light and emitting the produced white light from a backside of a display unit, the backlight device comprising:

• a chromaticity sensor that senses a chromaticity of the white light;
• a temperature sensor that senses temperature of the light source;
• and
• drive control means that supplies a current to the light emitting diodes of each color to drive the light emitting diodes, and implements feedback control of an amount of a current to the light emitting diodes of each color based on a value sensed by the chromaticity sensor so that the white light has a certain chromaticity, wherein
• the drive control means fixes an amount of a current flowing through the light emitting diodes of blue and adjusts amounts of currents flowing through the light emitting diodes of red and green to thereby implement the feedback control so that the white light has a certain chromaticity.

A method of driving a backlight device, the backlight device having a plurality of light emitting diodes of at least three colors as a light source, the backlight device synthesizing light emitted from the light emitting diodes of each color to produce white light and emitting the produced white light from a backside of a display unit, the method comprising the steps of:

• storing an initial current amount for the light emitting diodes of each color and a correction amount for the initial current amount, the correction amount depending on temperature;
• calculating, upon powering on the backlight device, the correction amount based on a value sensed by a temperature sensor that senses temperature of the light source;
• adding the calculated correction amount to the initial current amount of the light emitting diodes of each color;
• activating the light emitting diodes of each color with a corrected initial current amount;
• and
• implementing feedback control of an amount of a current to the light emitting diodes of each color based on a value sensed by a chromaticity sensor that senses a chromaticity of the white light so that the white light has a certain chromaticity.

A liquid crystal display apparatus including a backlight device and a transparent color liquid crystal display panel, the backlight device having a plurality of light emitting diodes of at least three colors as a light source and synthesizing light emitted from the light emitting diodes of each color to produce white light, the transparent color liquid crystal display panel being irradiated with the produced white light from a backside of the transparent color liquid crystal display panel, the backlight device comprising:

• a temperature sensor that senses temperature of the light source;
• a chromaticity sensor that senses a chromaticity of the white light;
• drive control means that supplies a current to the light emitting diodes of each color to drive the light emitting diodes;
• and
• storage means that stores an initial current amount for the light emitting diodes of each color and a correction amount for the initial current amount, the correction amount depending on temperature, wherein:
• the drive control means calculates, upon powering on the backlight device, the correction amount based on a value sensed by the temperature sensor, the drive control means adding the calculated correction amount to the initial current amount of the light emitting diodes of each color and activating the light emitting diodes of each color with a corrected initial current amount;
• and
• the drive control means implements feedback control of an amount of a current to the light emitting diodes of each color based on a value sensed by the chromaticity sensor so that the white light has a certain chromaticity.

A liquid crystal display apparatus including a backlight device and a transparent color liquid crystal display panel, the backlight device having light emitting diodes of red, green and blue as a light source and synthesizing light emitted from the light emitting diodes of each color to produce white light, the transparent color liquid crystal display panel being irradiated with the produced white light from a backside of the transparent color liquid crystal display panel, the backlight device comprising:

• a chromaticity sensor that senses a chromaticity of the white light;
• a temperature sensor that senses temperature of the light source;
• and
• drive control means that supplies a current to the light emitting diodes of each color to drive the light emitting diodes, and implements feedback control of an amount of a current to the light emitting diodes of each color based on a value sensed by the chromaticity sensor so that the white light has a certain chromaticity, wherein
• the drive control means fixes an amount of a current flowing through the light emitting diodes of blue and adjusts amounts of currents flowing through the light emitting diodes of red and green to thereby implement the feedback control so that the white light has a certain chromaticity.