Illumination intensity correcting circuit

An illumination intensity correcting circuit for performing gamma-correction on three primary color signals comprising:

• first, second, and third correcting circuits respectively receiving as inputs red, green, and blue primary color signals and comprising:
• differential amplifier circuits for respectively generating signals corresponding to the difference between voltages of the three primary color signals and the reference voltages of the differential amplifier circuits,
• a synthesizing circuit including a differential amplifier circuit to synthesize output signals of the differential amplifier circuits, and
• a load resistor with one terminal connected to an input terminal of a source voltage and with another terminal connected to an output terminal of the synthesizing circuit, wherein
• a curve fitting circuit whose amplification factor is changed before and after each breakpoint voltage is formed by the differential amplifier circuits, the synthesizing circuit, and the load resistor,
• the reference voltages of the differential amplifier circuits are set so that a breakpoint voltage is arranged in the range of the voltages of the three primary color signals, and
• the amplification factors of the differential amplifier circuits are set so that an amplification factor of the curve fitting circuit in a range of the signal voltage lower than the breakpoint voltage is larger than the amplification factor of the curve fitting circuit in a range higher than the breakpoint voltage.