| 摘要 |
PROBLEM TO BE SOLVED: To provide a road face projection system by which a projection image can be viewed without making an occupant of an own vehicle wear glasses or the like while suppressing that the projection image on a road face is viewed by a person existing outside the own vehicle.SOLUTION: A road face projection system 10 comprises: an on-vehicle projector 12 which projects an image on a road face in front of a vehicle by near infrared light; a front window 13 in which a polarization control element 13a which functions as a quarter wavelength plate in a period of the application of a voltage, a polarization beam splitter 13b, and a wavelength conversion element 13c which converts near infrared light to visible light are laminated on one another from the outside of a vehicle, and which is switched to a state that the near infrared light permeates the polarization beam splitter by voltage control, or to a state that the near infrared light does not permeate the polarization beam splitter; and a control part 14 which pulse-oscillates the near infrared light when performing image projection by the near infrared light, and makes an oscillation cycle of the near infrared light and a permeation cycle of the near infrared light in the polarization beam splitter synchronized with each other by the voltage control applied to the polarization control element.SELECTED DRAWING: Figure 6 |
