Patent ID: 8339292

Claim:
A key operation device for detecting an open/close state of each of a plurality of key switches through a plurality of row and column signal lines that are coupled to form a matrix, wherein the key switches include: a 1 st key switch corresponding to a key for inputting a 1 st direction; a 2 nd key switch corresponding to a key for inputting a 2 nd direction opposite to the 1 st direction; a 3 rd key switch corresponding to a key for inputting a 3 rd direction different from the 1 st and 2 nd directions; a 4 th key switch corresponding to a key for inputting a 4 th direction opposite to the 3 rd direction; and a plurality of ten-key switches corresponding one-to-one to a plurality of keys of a ten-key pad, wherein the 1 st and 2 nd key switches are (i) both coupled to a same one of the row signal lines and (ii) each coupled to a different one of the column signal lines, the 3 rd and 4 th key switches are (i) both coupled to a same one of the row signal lines other than the one to which the 1 st and 2 nd key switches are coupled, and (ii) each coupled to a different one of the two column signal lines to which the 1 st and 2 nd key switches are respectively coupled, and the ten-key switches include a plurality of first ten-key switches that are (i) coupled to one or more of the row signal lines, wherein the one or more of the row signal lines do not comprise the two row signal lines to which the 1 st and 2 nd or 3 rd and 4 th key switches are coupled and (ii) coupled to two or more of the column signal lines, wherein the two or more of the column signal lines comprise at least one of the two column signal lines to which the 1 st , 2 nd , 3 rd , or 4 th switch are coupled.