Abstract: A light guide unit guides a display light toward a projection member. A multilayer film filter unit transmits the display light with an optical multilayer film and shields an external light incident from a projection window. In the XYZ color system, a first wavelength region is between a wavelength having a maximum value of a color matching function Z and a wavelength having a maximum value of a color matching function Y. A second wavelength region is between the wavelength having the maximum value of the color matching function Y and a wavelength having a maximum value of a color matching function X. A minimum transmittance of the multilayer film filter unit to the display light takes a minimum value among transmittances of respective wavelengths in a target wavelength region. The minimum transmittance in the first wavelength region is smaller than that in the second wavelength region.

Abstract: A light guide unit has a cold mirror unit to guide display light toward a projection window. In an XYZ color system, a wavelength region between a wavelength at which a value of a color matching function Z is maximum and a wavelength at which a value of the color matching function Y is maximum is a first wavelength region, and a wavelength region between a wavelength at which a value of a color matching function Y is maximum and a wavelength at which a value of a color matching function X is maximum is a second wavelength region. A minimum reflectance of the cold mirror unit to the display light takes a minimum value among reflectances of the respective wavelengths in a corresponding wavelength region. The minimum reflectance in the second wavelength region is larger than the minimum reflectance in the first wavelength region.

Abstract: A head-up display device includes an illumination optical system, an imaging optical system and a reflective optical system. The illumination optical system emits a source light indicating information. The imaging optical system projects the source light to a projection surface. The reflective optical system has a dielectric multilayer film, and is configured so that a retardation of a subject wavelength including at least a part of wavelengths of the source light from the illumination optical system is in a range greater than ??/2 [rad] and smaller than ?/2 [rad]. The reflective optical system is arranged on a path from the illumination optical system to the imaging system so that a polarization axis of the source light from the illumination optical system defines an angle ? satisfying a relation of 0 degree <?<90 degrees <?<180 degrees, relative to an incident surface.

Abstract: A light guide unit has a cold mirror unit to guide display light toward a projection window. In an XYZ color system, a wavelength region between a wavelength at which a value of a color matching function Z is maximum and a wavelength at which a value of the color matching function Y is maximum is a first wavelength region, and a wavelength region between a wavelength at which a value of a color matching function Y is maximum and a wavelength at which a value of a color matching function X is maximum is a second wavelength region. A minimum reflectance of the cold mirror unit to the display light takes a minimum value among reflectances of the respective wavelengths in a corresponding wavelength region. The minimum reflectance in the second wavelength region is larger than the minimum reflectance in the first wavelength region.

Abstract: A light guide unit guides a display light toward a projection member. A multilayer film filter unit transmits the display light with an optical multilayer film and shields an external light incident from a projection window. In the XYZ color system, a first wavelength region is between a wavelength having a maximum value of a color matching function Z and a wavelength having a maximum value of a color matching function Y. A second wavelength region is between the wavelength having the maximum value of the color matching function Y and a wavelength having a maximum value of a color matching function X. A minimum transmittance of the multilayer film filter unit to the display light takes a minimum value among transmittances of respective wavelengths in a target wavelength region. The minimum transmittance in the first wavelength region is smaller than that in the second wavelength region.

Abstract: A head-up display device includes an illumination optical system, an imaging optical system and a reflective optical system. The illumination optical system emits a source light indicating information. The imaging optical system projects the source light to a projection surface. The reflective optical system has a dielectric multilayer film, and is configured so that a retardation of a subject wavelength including at least a part of wavelengths of the source light from the illumination optical system is in a range greater than ??/2 [rad] and smaller than ?/2 [rad]. The reflective optical system is arranged on a path from the illumination optical system to the imaging system so that a polarization axis of the source light from the illumination optical system defines an angle ? satisfying a relation of 0 degree <?<90 degrees <?<180 degrees, relative to an incident surface.

Abstract: A head-up display device is mounted in a vehicle and virtually displays an image to be viewable by an occupant by projecting the image on a light-transmissive projection member. The head-up display device includes a projector that projects the image as light polarized in a direction of a polarization axis, a polarizer that is disposed on an optical path of the light of the image and has a property of transmitting light polarized along a transmission axis, and a phase shifter that is disposed between the polarizer and the projection member on the optical path and has a property of changing a polarization direction of transmitted light by producing a phase difference. A fast axis direction of the phase shifter intersects with a direction corresponding to the polarization axis, a direction corresponding to the transmission axis, and a direction corresponding to S polarization of the projection member.