Sony Corp. said Monday that it will make palmtop mobile personal computer terminals a major part of its electronics product lineup.

“We will make that device the fourth pillar of our product lineup,” Sony Vice President Kunitake Ando said. The other three pillars are PCs, televisions and video game consoles.

Ando, who is to succeed company President Nobuyuki Idei, will have his appointment approved at a board of directors meeting slated for June 29.

Sony will market its first palmtop mobile terminal in September, Sony officials said.

Sony has been lagging behind Mitsubishi Electric Corp. and Matsushita Electric Industrial Co. in the fast-growing business area of palm-size mobile terminals, such as cellular phones and personal digital assistants.

Sony will expand the scope of the market for PDAs by adding an ultrasmall memory device that is capable of recording large volumes of music and moving images onto conventional PDAs for business use, the officials said.

Other manufacturers’ PDAs, packed with business-related features, have been used mainly by businessmen who want to keep precise track of their schedules.

Sony plans to equip its upcoming lineup of palmtop mobile terminals with an operating system made by Palm Inc. of the United States, whose OS for palmtop terminals dominates the U.S. market, the officials said.

Sony wants to eliminate its vulnerability to yen appreciation by having overseas manufacturers make Sony electronics products, they said.

But Sony will exempt high value-added products such as notebook PCs and products that incorporate sophisticated technology from products whose manufacture can be entrusted to overseas makers, they said.

In addition, Sony will funnel more business resources into the PC market in South Korea, Australia, and other Asian and Oceanic countries, although it has placed greater emphasis on the U.S. and Japanese markets, they added.