Optical characteristic measurement apparatus and optical system

An optical characteristic measurement apparatus comprising:

• a movable first optical element including at least one curved optic positioned to receive diverging measurement light from a measurement target object and to transmit or reflect the received measurement light as parallel light;
• a reflective lens, comprising a curved mirror, configured to reflect the parallel light from the movable first optical element to convert the parallel light to convergent light;
• a second optical element, including at least one mirror, arranged on an optical path between the movable first optical element and the reflective lens, the at least one mirror positioned to reflect the parallel light from the movable first optical element to vary a direction of propagation of the parallel light;
• a spectroscope configured to receive the convergent light from the reflective lens;
• an actuator coupled to the movable first optical element, the actuator operable to vary a position of the movable first optical element relative to the measurement target object;
• a first light source configured to produce measurement light for irradiation of the measurement target object;
• and
• a beam splitter which is arranged on an optical path from the reflective lens to the spectroscope and is optically connected to the first light source.