Panasonic Corp., though dogged by repeated delays, finally announced Thursday it acquired a 50.19 percent stake in smaller Sanyo Electric Co. for ¥403.78 billion as it makes headway in its transition into a green consumer electronics giant that can remain globally competitive in the decades ahead.

The rise of the solar and battery behemoth will pose a key litmus test for Japan's struggling electronics industry as its traditional gadgets and appliances lose their spark on steep price declines driven by overseas rivals.

"This is probably the first time we are seeing a strong consumer brand . . . really trying to push the consumer end solution" with products ranging from solar cells and rechargeable batteries to consumer products, said David Gibson, head of research at Macquarie Securities Ltd. in Tokyo. "The combination is really quite a change in the business."