UPDATE 2-Idex to buy photonics company CVI for $400 mln

* Says CVI to be part of health & science tech segment

* CVI to add to earnings within first full year of deal (Adds details on the deal, companies)

May 11 (Reuters) - Industrial products maker Idex Corp said it agreed to buy CVI Melles Griot from private equity firm Norwest Equity Partners for about $400 million as it tries to expand its optics and photonics platform.

CVI will operate within Idex's health and science technologies segment. Idex expects CVI to add to earnings within the first full year after the acquisition.

Albuquerque, New Mexico-based CVI, which has annual revenue of about $185 million, makes lasers and optical equipment used in the life sciences, research, semiconductor, security and defense markets.

CVI is Idex's third acquisition in the photonics market in as many years.

The Lake Forest, Illinois-based company this year acquired Advanced Thin Films, a precision thin-film coatings company. In 2008, Idex had acquired Semrock.

Idex, which has a market value of about $3.8 billion and reported 2010 annual revenue of about $1.5 billion, caters to diverse industries with products like air motors, industrial pumps, dispensing equipments and flow meters.

Idex shares closed at $46.07 on Tuesday on the New York Stock Exchange. (Reporting by Bijoy Koyitty in Bangalore; Editing by Maju Samuel) (bijoy.koyitty@thomsonreuters.com; within U.S. +1 646 223 8780; outside U.S. +91 80 4135 5800; Reuters Messaging: bijoy.koyitty.reuters.com@reuters.net))