The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 17, 2001
Filed:
May. 24, 1999
Tadashi Tamukai, Tokyo, JP;
Asia Electronics, Inc., Tokyo, JP;
Abstract
The pixel capacitances of an LCD array can be inspected easily and in a short time without being affected by the capacitance of the tester system. On the first occasion, pixel capacitance C,is charged with pixel voltage V,and line capacitance C,(C,>>C,) that is connected in parallel with pixel capacitance C,is charged with set voltage V,(V,≠V,). By connecting pixel capacitance C,and line capacitance C,is parallel, the difference voltage &Dgr;V,of the voltage of the line capacitance C,after the parallel connection and the set voltage V,that is charged thereon before the parallel connection is measured. On the second occasion, pixel capacitance C,is charged with pixel voltage V,and a known reference capacitance &Dgr;C,is connected in parallel with line capacitance C,, this being charged with set voltage V,. By further connecting in parallel pixel capacitance C,with the parallel-connected line capacitance and reference capacitance &Dgr;C,, the difference voltage &Dgr;V,of the line capacitance C,after this parallel connection and the set voltage V,that was charged thereon prior to the parallel connection is measured. The pixel capacitance C,is found from these difference voltages &Dgr;V,, &Dgr;V,measured on the first and second occasion and an equation C,=&Dgr;C,·&Dgr;V,·&Dgr;V,/((V,−V,)·(&Dgr;V,−&Dgr;V,)) derived from the difference voltages.