Patent ID: 7474168

Claim:
An apparatus for generating a modulation signal whose height value and the time width thereof are controlled in accordance with an input value of luminance-tone data, said apparatus comprising: a control circuit; and an output section, wherein the control circuit defines a maximum time width which is available as a time width of a first height value of the modulation signal and sets a predetermined value of luminance-tone data corresponding to the modulation signal whose first-height-value time width is controlled so as to be the maximum time width, wherein the output section outputs, when an input value of the luminance-tone data is not more than the predetermined value, the modulation signal whose first-height-value time width is controlled so that the upper limit of the first-height-value time width is the maximum time width in accordance with the input value of the luminance-tone data, and the output section outputs, when the input value of the luminance-tone data is higher than the predetermined value, the modulation signal whose first-height-value time width is controlled to be the maximum time width and whose time width of a second height value, which is higher than the first height value, is controlled in accordance with a value which exceeds the predetermined value in a period which is different from a period in which the first height value is controlled, and wherein the control circuit changes the maximum time width in accordance with a signal input to the control circuit and changes the predetermined value in accordance with the signal input to the control circuit.