Projection optical system and head-up display apparatus using the same

A head-up display apparatus, comprising:

• an image formation unit including a liquid crystal display panel configured to emit light as image information, a relay optical system configured to guide the light from the liquid crystal display panel, and a screen panel disposed to receive the light from the relay optical system and form an intermediate image;
• and
• an eyepiece optical system configured to display a virtual image by reflecting light, corresponding to the intermediate image, which is emitted from the screen panel of the image formation unit,
• wherein the eyepiece optical system includes a first optical element having a negative refractive power and which transmits the light emitted from the screen panel, a second optical element having a positive refractive power, a surface lens, and a concave reflecting mirror,
• the eyepiece optical system is configured with the first optical element, the second optical element, the surface lens, and the reflecting mirror disposed in this order from the screen panel of the image formation unit, and
• wherein the eyepiece optical system is disposed behind the screen panel with respect to a path of the light emitted from the relay optical system.