SEMI D64 - Test Method for Measuring the Spatial Contrast Ratio of Flat Panel Display
Contrast has a significant influence on the perceived image quality in display devices.</p><p>For several decades, physical contrast metrics such as contrast ratio (CR) and contrast modulation (CM) have been widely used to quantify the contrast performance of display devices.
A robust standardized test method for measuring the APL (average picture level) contrast ratios of flat panel display (FPD) systems is required to enable quality control in high volume manufacturing.
Existing international standards use full screen sequential test patterns that are not suitable for modern FPD systems that dynamically adjust gray levels based on image contents. International standards (IEC, ISO and VESA FPDM) define the contrast ratio (CR) and contrast modulation (CM).
Sequential full screen test pattern does not give constant results for the new display technologies that dynamically adjust gray levels based on image contents.
The test pattern where regions of various APL exist inside one image, therefore, is more reliable to assess the display device in terms of contrast ratio. APL values of various images, therefore, should be considered.
Consequently, this Test Method requires a pair of specified test patterns with APL variation, rather than sequential APL variation, used to evaluate the APL contrast ratio of a display device under test.
Referenced SEMI Standards
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