Method for detecting defects in a rod-shaped transparent object

    公开(公告)号:US09939390B2

    公开(公告)日:2018-04-10

    申请号:US14899840

    申请日:2013-06-25

    Abstract: A method for inspecting defects inside a rod-shaped transparent object by using a scanning beam of parallel light rays directed onto a rod-shaped transparent object orthogonally to the longitudinal axis of the object so that an inspection plane comprises an object's cross-section. The scanning beam is detected at an opposite side of the rod-shaped object that is interposed to intercept the parallel rays of the scanning beam. The electric output signal from the detector is processed to produce a first light intensity profile in a first scan direction, the light intensity profile comprising a shadow region delimited by first and second shadow edges, which is indicative of the outside diameter of the object across the inspection plane. The method comprises analyzing the first light intensity profile to determine the presence or absence of a peak of positive intensity within the shadow region and, if an intensity peak is determined to be present, to determine the presence or absence of a region of depressed intensity within the intensity peak. If, as a result of analyzing, an intensity peak within the shadow region is determined to be absent or a region of depressed intensity is determined to be present within the intensity peak, the presence of at least one structural defect within the object's cross-section is identified. In the preferred embodiments, the rod-shaped transparent object is a glass core rod for the production of a transmission optical fiber.

    MULTI-SURFACE SPECULAR REFLECTION INSPECTOR
    114.
    发明申请

    公开(公告)号:US20170336331A1

    公开(公告)日:2017-11-23

    申请号:US15159626

    申请日:2016-05-19

    Abstract: An optical inspector includes a time varying beam reflector, a radiating source that irradiates the time varying beam reflector, a telecentric scan lens configured to direct the radiation reflected by the time varying beam reflector onto a first surface of a transparent sample, a first detector that receives at least a portion of top surface specular reflection, a second detector that receives at least a portion of the bottom surface specular reflection. A turning mirror may also be included. The turning mirror is a switchable mirror that can be adjusted to a first position where the turning mirror reflects the top and bottom surface specular reflection, and can be adjusted to a second position where the turning mirror does not reflect the top or the bottom surface specular reflection. A first and second polarizing element may also be included to detect additional types of defects on either surface.

Patent Agency Ranking