Optical interprogation system for use in constructing flat tension shadow mask CRTS

In the manufacture of CRTs a system for registering undedicated flat tension masks to phosphorescent screens deposited on CRT front panels, comprising:

• (a) an assembly station where the mask and panel are joined together;
• (b) a mask module for supporting the mask for transport to the assembly station;
• (c) a panel module for supporting the panel for transport to the assembly station;
• (d) module registration means at the assembly station for locating serially the mask module and the panel module;
• (e) interrogation means for interrogating the mask and the panel to determine the locations of the desired features of the mask and panel, including:
• 1. ) a spaced array of video cameras, each camera located in a known position and each producing a video signal electronically representing its field of view;
• 2.) means for sampling the signal to provide a series of pixels;
• each pixel having a single bit image value;
• 3.) means for parallel grouping of like-ordered pixel image values from each camera's pixel series into one or more bytes;
• and
• 4.) means for serially comparing the bytes to simultaneously determine, for each camera, the locations of transitions between its pixel image values;
• and,
• (f) movement means for producing registration movement between the mask and panel, the movement means being responsive to the interrogation means.

A method of interrogating at least one CRT workpiece, comprising:

• (a) positioning a plurality of cameras in known positions;
• (b) viewing at least one CRT workpiece with the plurality of cameras thereby establishing a field of view for each camera;
• (c) electronically representing the field of view of each camera as a series of pixels;
• (d) assigning each pixel a single-bit image value;
• (e) serially comparing each camera's series of pixel image values in parallel to determine where transitions take place between pixel image values for each camera;
• (f) processing the transition locations to determine where desired features in the fields of view occur

A method of registering and assembling a CRT faceplate assembly including a shadow mask and a screened panel comprising:

• (a) placing an array of video cameras in known position to view the panel and the shadow mask;
• (b) simultaneously viewing the shadow mask and the panel with the cameras thereby producing from each camera a video signal electronically representing the field of view of each camera;
• (c) dividing each signal into a series of pixels each having a single bit image value;
• (d) grouping like-ordered binary pixel image values, from the pixel series of each camera, in parallel into one or more bytes;
• (e) serially comparing bytes to simultaneously determine the locations of transitions between the pixel image values for each camera;
• and,
• (f) registering and joining the panel and the shadow mask according to the locations determined.

An apparatus for simultaneous optical interrogation of a plurality of fields on CRT shadow mask and screened faceplate comprising;

• a) two spaced arrays of video cameras, one array viewing the shadow mask and one array viewing the faceplate, each camera located in a known position and producing a video signal electronically representing its field of view;
• b) means for dividing each signal into a series of pixels;
• c) means for valuing each pixel of each signal in a single bit image value;
• d) means for grouping like ordered pixel image values from each camera in parallel into one or more bytes;
• and,
• e) means for serially comparing the bytes to simultaneously determine the locations of transitions in the pixel image values for each camera.