A glass substrate unit includes a glass substrate and a glass deformation device for deforming the glass substrate. The glass substrate includes a thin portion and a thick portion, the thin portion having a first main surface and a second main surface opposite to the first main surface, the thick portion having a first main surface and a second main surface opposite to the first main surface and having a sheet thickness larger than a sheet thickness of the thin portion. The glass deformation device deforms the glass substrate by moving one of the thin portion and the thick portion.

A head-up display (HUD) apparatus comprises a housing including a lower case that is open at a top thereof and defines an internal space, and an upper case that corresponds to the lower case to cover the top of the lower case; an aspherical mirror configured to reflect an image emitted from a picture generation unit onto a windshield, and the aspherical mirror being disposed in the lower case; and a crumple zone including an impact absorbing unit configured to be disposed in the housing and to absorb an impact transmitted to the housing, in the event of a vehicle collision.