Dainippon Screen Seizo Kabushiki-kaisha

Dainippon Screen Mfg. Co., Ltd.

Tetsuo Hohki

Seiya Sakamoto

Tetsuo Sano

Eiji Kodama

Hisayuki Tsujinaka

Isao Saito

Makoto Hirosawa

Takumi Yoshida

Yasuo Kurusu

Masafumi Kawatani

Tatsunosuke Masuda

Printed wiring boards (PWBs) applied to this inspection system are previously formed with marks in prescribed positional relation to wiring patterns. Deviation of PWBs with respect to absolute coordinates of the inspection system is detected by reading the marks. The PWBs are sequentially set one by one on a movable table, to be subjected to image acquisition of the marks and inspected areas. A first PWB is image-acquisited whereby obtained binary image data of the inspected area are stored in a memory unit. Thereafter a second PWB is image-acquisited, and in advance to the image acquisition of its inspected area, relative misregistration of the both PWBs is found by deviation data on respective marks of the first and second PWBs. The binary image data of the first PWB is read from the memory unit on the basis of the binary image data of the second PWB. When the binary image data of the first PWB are read, positional correction, i.e., time base correction is performed on the read data to correspond to pixels of the second PWB under image acquisition on the basis of data on the previously found amount of relative misregistration. The data on corresponding pixels of the both PWBs are compared with each other thereby to inspect difference between the patterns of the PWBs on the basis of the result of the comparison.

System for inspecting pattern defects of printed wiring boards

Disclosed herein is an image pickup apparatus for a printed wiring board comprising a solid state image sensor whose light receiving surface is set to be opposed to the surface of the printed wiring board, a main illumination source arranged to satisfy the law of regular reflection on the surface of the printed wiring board with respect to the light receiving surface of the solid state image sensor and a subsidiary illumination source arranged not to satisfy the law of regular reflection with respect to the light receiving surface of the solid state image sensor thereby to supply the light receiving surface with scattering light by strias formed on copper patterns. The amount of regularly reflected light, which is changed depending on the strias formed on the copper patterns, is substantially compensated by the scattering light, so that the amounts of light received by the solid state image sensor relating to the copper patterns are made substantially constant regardless of the radiation pattern of the strias. In addition, the main and subsidiary illumination sources are formed by light emitting diodes thereby to attain technical and economical advantages.

Image pickup apparatus for a printed wiring board

An improved apparatus for measuring the printed area of a printing plate upon which a printing image is formed, of the type having a movable scanning head provided with longitudinally arranged light sources and plural photosensors arranged in parallel with the light sources. The improvement is composed of a proving sensor device separate from and movable independently of the scanning head which includes at least one light source and photosensor. The proving sensor device provides calibration data for correcting the measurements made by the scanning head. It does this by measuring the intensity of reflected light from a totally dark printing area and a non-printing area from anywhere on the printing plate, and a totally reflective surface and totally absorptive surface, which are preferably located apart from the printing plate. The improvement further includes control means for electronically processing the measurement data produced by both the scanning head and proving sensor device.

Printed area measuring apparatus

A method for stabilizing the intensity of a light beam emitted by a light source and deflected by an acoustooptical deflector element which is controlled by a control signal and is arranged in a scanning exposure head, without regard to deflection angles, wherein a detected light beam intensity is compared with a predetermined reference light intensity. The difference between the light beam intensity and the reference light intensity is detected, and wherein the control signal corresponding to the detected difference is controlled by a stored correction signal which is read out of a memory, so that the intensity of the light beam through the acoustooptical deflector element may be maintained at a certain level.

Light beam intensity stabilizing method

A method for determining a supplementary amount of a developing solution for use in a film developer, wherein values of width signals for controlling a halftone dot generator of a picture reproducing machine are counted up, while a reproduction picture is recorded on a photosensitive film by the halftone dot generator according to picture signals which are obtained by scanning an original picture photoelectrically, and wherein a supplementary amount of the developing solution is determined according to the counted-up total value of the width signals prior to the development of the photosensitive film.

Supplementary amount of developing solution determining method for a

A spot of light is formed upon a photosensitive material which is moved in a scanning direction, and the spot is vibrated to and fro along a vibration direction at a considerable angle to the scanning direction, and the amplitude of vibration, and the center of the vibration path, are controlled so that the spot exposes areas on the photosensitive material which form half-tone dots.

Method of producing a halftone picture by vibrating light source

A device for reproducing a halftone picture by scanning, representing a marked simplification over conventional devices of this type. The recording beam is controlled by two deflection means and an aperture of simple shape and the control means allows dot patterns with a screen angle to be produced very simply.

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Ibaragi, Japan

Tetsuo Hohki