A flat lighting source is provided which is capable of applying illuminating light to an entire display region of a display panel. A current or voltage is supplied from each LED (Light Emitting Diode) driving/correcting circuit to each LED. Part of light emitted from each of the LEDs is converted into electrical signals and a resistance value of each photodiode decreases in proportion to luminance. If luminance of light emitted from each of the LEDs increases, a resistance value of each of the photodiodes decreases while the luminance of light emitted from each of the LEDs decreases. The resistance value is fed back to each of the LED driving/correcting circuits which changes a driving current or a driving voltage so that luminance of light emitted from each of the LEDs corresponds to a luminance setting voltage. The photodiode is mounted in a one-to-one relationship for every LED.
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