Patent ID: 8830157

Claim:
A quantity-of-light adjusting method for a display apparatus, which controls with pulse width modulation a quantity of light of a light source irradiating light onto a display configured to display an image, the method comprising: controlling the quantity of light of the light source by varying a ratio of a light-on period, during which the light source is repeatedly turned on and off using the pulse width modulation, to a light-off period, during which the light source remains off for an interval that is longer than any interval that the light source is turned off using the pulse width modulation, wherein to adjust a highest quantity of light of the light source to be a predefined quantity of light or larger, performing control by setting the ratio of the light-on period at 100% and varying the pulse width of the pulse width modulation until a pulse width corresponding to the quantity of light is obtained, in which the predefined quantity of light is approximately 25% of the light, and when the highest quantity of light of the light source is adjusted to be in a range of the approximately 25% of the light or larger, to adjust the quantity of light of the light source to a quantity of light in a range of approximately 10% of the light or smaller, performing control by varying the ratio of the light-on period to the light-off period while keeping the pulse width constant.