Hitachi, Ltd.

Masao Taniguchi

Shigemi Hirasawa

Atsushi Yoshida

Eiichi Yamazaki

Hiromi Kanai

Toshio Asano

Kazuo Majima

Jun Mochizuki

Daisuke Katsuta

Kinuyo Hagimae

Teruo Matsuo

An apparatus for identifying positions of pixel defects on a display screen, such as a cathode-ray tube or a liquid crystal display, operates to pick up an image signal of a display screen representing a predetermined image with an imaging camera, shift the image signal of the imaging camera by one pixel in one and another directions with respect to the display screen, and obtain a difference of a signal level between a defective portion and a normal portion on the screen, based on the signals obtained when the image signal of the imaging camera is shifted in one and another directions. The apparatus also serves to calculate a relative inclination between the imaging camera and the display screen for obtaining a difference of a signal level between a defective portion and a normal portion of each pixel. The results make it possible to clearly identify the difference of the signal level between the defective portion and the normal portion.

Method and apparatus for checking defect on display screen

A phosphor screen for a post-focusing type color picture tube comprising a faceplate, a phosphor layer on the faceplate, a metal back layer on the phosphor layer and a secondary electron emission suppressing layer on the metal backed phosphor screen, in which the thickness of the metal back layer and the density of the secondary electron emission suppressing layer take particular values for effective suppression of emission of secondary electrons from the phosphor screen.

Phosphor screen for post-focusing type color picture tube

Growing community of inventors

Mobara, Japan

Masao Taniguchi