Liquid-crystal luminous quantity adjuster, method for driving liquid crystal luminous quantity adjuster, and camera comprising liquid crystal luminous quantity adjuster

A camera comprising:

• an optical system for focusing light coming from a target on an imaging surface;
• a liquid-crystal light-amount adjusting unit for adjusting the amount of the light that reaches the imaging surface, by changing an optical transmittance of a liquid crystal;
• a driving-pulse generating circuit for generating driving pulses having pulsed voltages, the driving pulses being supplied to the liquid crystal to change the optical transmittance;
• and
• a control circuit for controlling frequencies and duty ratios of the driving pulses;
• wherein the control circuit exercises control so that the driving-pulse generating circuit generates driving pulses for acceleration, having a first frequency and a first duty ratio, and driving pulses for dimming, having a second frequency that is different from the first frequency and a second duty ratio that is different from the first duty ratio.

A camera comprising:

• an optical system for focusing light coming from a target on an imaging surface;
• a liquid-crystal light-amount adjusting unit for adjusting the amount of the light that reaches the imaging surface, by changing an optical transmittance of a liquid crystal;
• a driving-pulse generating circuit for generating driving pulses having pulsed voltages, the driving pulses being supplied to the liquid crystal to change the optical transmittance;
• and
• a control circuit for controlling a frequency and a duty ratio of the driving pulses;
• wherein the control circuit changes the frequency of the driving pulses during-imaging for one screen.