Patent ID: 7615253

Claim:
A method for visual marking glass panes that are tempered and then heat-treated, the method comprising: producing a marking field that includes an uneven surface structure on a limited area of a smooth side surface of a glass pane, wherein the limited area is smaller than a total area of the side surface of the glass pane, and wherein the uneven surface structure is more rough than portions of the side surface of the glass pane that are outside of the limited area of the side surface of the glass pane; depositing a marking layer on the marking field such that the marking layer penetrates intermediate spaces or hollows within the marking field so as to create an intimate adhesive bond between the marking layer and the marking field; and modifying the marking layer deposited on the marking field via heat treatment, wherein the marking layer visually indicates that the heat treatment has been carried out, and wherein the color of the marking layer is irreversibly modified by the heat treatment.