IEC 62977-2-1:2021 pdf download.Electronic displays
5.2 Standard measuring darkroom conditions
The luminance contribution from unwanted background illumination reflected off the test display shall be less than 1/20 of the display's black state luminance. The reflected background luminance can be approximated by turning off the display. When the reflected background luminance and total (reflected plus black) luminance are greater than the sensitivity limit of the LMD，then it is possible to calculate the black luminance by subtracting the background luminance from the total luminance. If the reflected background luminance or total luminance are similar to the sensitivity limit of the LMD, this shall be reported. In cases where the display has a very low luminance black state, a stray light elimination tube (according to ISO 9241-305)should be used to minimize the contribution of the background illumination. This method can be used to estimate the reflected luminance from the black state luminance.
NOTE Blackout curtains are a solution for reducing the reflection from the DUT.
5.3.2 Adjustment of display
The display shall be configured to the specified settings, and the settings recorded in the test report. These settings shall be held constant for all measurements. It is important, however, to make sure that not only the adjustments are kept constant, but also that the resulting physical quantities remain constant during the measurement. This is not automatically the case because of, for example, warm-up effects or auto-dimming features. Any automatic luminance or gain control shall be turned off. Otherwise it should be noted in the report. The ambient light (or brightness) control (ABC)，which can reduce the display luminance level with dim ambient illumination, shall be turned off. If that is not possible, it is recommended to set it to turn on no lower than 300 lx to minimize the influence of the ABC. The state of the ABC shall be reported.
In addition, if the display has an auto-dimming feature which reduces the display luminance of a static image after a prolonged time, then at least an 8 s black frame shall be rendered prior to rendering and measuring the desired test pattern. The measurements shall be completed before the dimming feature is triggered. When the display has the option to be set for different viewing modes, the viewing mode shall be defined by the test specification, and be used with consistency for all measurements. Additional viewing modes can also be measured. The viewing mode used during testing shall be reported. The display should be operated in a mode that does not have overscan.IEC 62977-2-1 pdf download.