Patent attributes
Provided is a head-up display (HUD) device capable of effectively preventing damage to a liquid-crystal display device due to entry of exterior light. A HUD device has a liquid-crystal panel, and is provided with a liquid-crystal display device for realizing a transparent display using light from a backlight, a control means for controlling the liquid-crystal display device, and an optical system for reflecting the display light outputted by the liquid-crystal display device onto a windshield. A flat mirror constituting the optical system allows infrared rays of incident light to pass behind the mirror and reflects the visible light. The HUD device is provided with an infrared-ray sensor positioned behind the flat mirror, and the control means reduces the brightness of the light of the backlight or extinguishes the backlight when the strength detected by the infrared-ray sensor exceeds a predetermined threshold.
