CONTRAST RATIO MEASURING INSTRUMENT AND MEASUREING METHOD FOR CONTRAST RATIO

摘要

An apparatus for measuring contrast ratio and a method for measuring the contrast ratio are provided to reliably and promptly measure the contrast ratio by standardizing important elements deciding brightness maximally. An apparatus for measuring contrast ratio includes a light source(210), a first light passage converting unit(220), a first polarizing unit(230), a second polarizing unit(240), a light blocking unit(270), a second light passage converting unit(250), and a light measuring unit(260). The first light passage converting unit has a beam splitter(221) and a reflecting mirror(222). The beam splitter divides inputted light into a first light(A) and a second light(B). The reflecting mirror inputs the divided second light to the second polarizing unit due to reflecting the divided second light. The first and second polarizing units are composed of a pair of polarizing plates(230a-230b,240a-240b). The light blocking unit selectively blocks the light inputted from the first and second polarizing units due to the rotation drive, the right and left drive, or the top and bottom drive of the light shielding unit. The light measuring unit arranges a brightness measuring instrument on the same axis as the second polarizing unit.