IEC 62977-2-1-2021 Electronic displays – Part 2-1: Measurements of optical characteristics – Fundamental measurements

IEC 62977-2-1-2021 Electronic displays – Part 2-1: Measurements of optical characteristics – Fundamental measurements. 5 Standard measuring conditions 5.1 Standard measuring environmental conditions Measurements shall be carried out under the standard environmental conditions: – temperature: 25 °C ± 3 °C, – relative humidity: 25 % to 85 %, – atmospheric pressure: 86 kPa to 1 06 kPa. When different environmental conditions are used, they shall be noted in the report. 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 Standard setup conditions 5.3.1 General Standard setup conditions are given in 5.3. Any deviations from these conditions shall be reported. 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...