Head up display (hud) system and optical element for hud

A head up display (HUD) system, comprising:

• a light source configured to emit light of multiple wavelength bands for an HUD image;
• a first optical element configured to adjust the light of the multiple wavelength bands;
• and
• a second optical element comprising a first layer configured to enlarge a virtual image of the HUD image, a second layer configured to transmit a portion of the light of the multiple wavelength bands based on a transmittance set with respect to the multiple wavelength bands, and a third layer having a same refractive index as the first layer.

A head up display (HUD) system, comprising:

• a light source configured to provide light of first multiple wavelength bands for an HUD image;
• a first optical element configured to reflect the light of the first multiple wavelength bands provided by the light source, and transmit light of second multiple wavelength bands provided from an external light source outside of a vehicle;
• and
• a second optical element comprising:
• a first layer configured to enlarge a virtual image of the HUD image;
• a second layer configured to reflect the light of the first multiple wavelength bands reflected by the first optical element and light of the first multiple wavelength bands provided from the external light source outside of the vehicle, and transmit the light of the second multiple wavelength bands provided from the external light source outside of the vehicle;
• and
• a third layer, a refractive index of the third layer being equal to a refractive index of the first layer.

A head up display (HUD) system, comprising:

• a light source configured to emit light of first multiple wavelength bands for an HUD image;
• a first optical element configured to reflect the light of the first multiple wavelength bands;
• and
• a second optical element configured to reflect light of the first multiple wavelength bands reflected from the first optical element, the second optical element comprising:
• a Fresnel pattern layer comprising at least one Fresnel lens with inclined surfaces;
• a multiband coating layer formed on the inclined surfaces of the at least one Fresnel lens, the multiband coating layer configured to reflect light of the first multiple wavelength bands based on a reflectance set with respect to each of the first multiple wavelength bands;
• and
• an immersion layer formed on the multiband coating layer, a refractive index of the immersion layer being equal to a refractive index of the Fresnel pattern layer.