Abstract:
Bonded screens such as vehicle windscreens (1) bonded to a supporting frame (5) by homogeneous bonding material (6) are released by firstly arranging energy delivery means (9) adjacent the screen and subsequently transmitting energy from the delivery means through the screen thereby to effect release of the screen (1) from the frame (5) by either causing degradation of some of the homogeneous bonding material and/or cleavage or degradation of the screen material. The energy delivered may, for example, be ultrasonic or laser radiation, and is preferably arranged to be concentrated at a predetermined localized region to enhance the release mechanism.
Abstract:
A method of providing a body of material (14), having a thermal conductivity approximately equal to that of glass, with a sub-surface mark. A beam of laser radiation (12) to which the material (14) is substantially opaque is directed to surface of the body, so as to cause beam energy to be aborbed at the surface of the material in an amount sufficient to produce localised stresses within the body (14) at a location spaced from the surface without any detectable change at the surface, the localised stresses thus produced being normally invisible to the naked eye but capable of being rendered visible under polarised light.
Abstract:
A method and an apparatus for making a moving body of material (26). The method includes the steps of directing at the moving body a high energy density beam (46,58), concentrating the beam so as to produce an illuminated spot at a location on or within the moving body, and moving the spot in accordance with the resultant of two components of movement, the first component being equal to the velocity of the moving body and the second component being relative to the moving body, so as to create a mark of a predetermined shape. In a preferred embodiment, the apparatus includes at least one movable galvanometer mirror (68,70) capable of moving the spot in accordance with the resultant of the two components.