| 摘要 |
<p>Provided is a light source which performs a partially ON operation with illumination light having an improved detection accuracy. In an ON-quantity variable operation mode, control is performed so that a pulse width (T) of the immediately preceding pulse signal among a plurality of pulse signals generated during one-frame period by a backlight control unit (12) does not exceed a predetermined threshold value T2 (Tth). Even when a partially ON unit (4) has a high light emission luminance (a plurality of pulse signals are respectively wide), it is possible to prevent interference between a light reception signal obtained during a partially ON period (t1) and a light reception signal obtained during an entirely ON period (t4). This prevents fluctuation of the signal value of the acquired reception signal depending on its detection timing, thereby enhancing the detection accuracy.</p> |
