Image rendering apparatus, head up display, and image luminance adjusting method

An image rendering apparatus comprising:

• a light source unit configured to emit laser light;
• an optical scanner configured to scan the laser light in such a way that the laser light reciprocates in a main scanning direction and a sub scanning direction;
• a scanner control unit configured to control a frequency for the optical scanner to scan the laser light in the main scanning direction;
• and
• a light source driving unit configured to drive the light source unit based on image data, wherein
• the scanner control unit multiplies the frequency by n, the n being a natural number of two or greater, and
• the light source driving unit changes time intervals at which pixels are rendered on scanning lines in the main scanning direction to 1/nth and controls the light source unit in such a way that the light source unit renders a plurality of pixels corresponding to one scanning line at least once during n scans in the main scanning direction and in such a way that the light source unit will not render pixels on scanning line(s) other than the scanning lines on which the pixels have been rendered to thereby reduce a luminance of a rendered image.