Pentax Corporation (ペンタックス株式会社, Pentakkusu Kabushiki-gaisha) was a Japanese company founded in 1919 as Asahi Optical Joint Stock Co. (旭光学工業合資会社, Asahi Kōgaku Kōgyō Gōshi-gaisha?), spectacle lens manufacturers. The company was merged with and into Hoya Corporation on March 31, 2008.