Lens meter for measuring a refractive power of a lens

A lens meter for measuring a refractive power of an inspected lens in a condition that said lens meter is placed on a plane, said lens meter comprising:

• a lens holder for holding said inspected lens substantially parallel to said plane;
• a target projection optical system having illumination optical source and a measurement target, said target projection optical system projecting an image of said measurement target through said inspected lens;
• an ocular-type observation optical system having an ocular tube with a downwardly slanted observation optical axis through which an inspector observes said lens holder;
• an imaging optical system for imaging said image of said measurement target on a predetermined plane;
• movement means for moving said measurement target;
• and
• control means for controlling said illumination optical source including:
• a timer circuit for deenergizing said illumination optical source after a predetermined lapse of time,
• detecting means for detecting movement of said measurement target due to said movement means, and
• a trigger signal generating circuit for actuating said timer circuit based on a detection result by said detecting means.