IEC 62977-2-1-2021 pdf free
IEC 62977-2-1-2021 pdf free.Electronic displays – Part 2-1: Measurements of optical characteristics – Fundamental measurements.
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 924 1-305) 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 Ix 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.
5.3.3 StartIng conditions of measurements
Measurements shall be started after the displays and measuring instruments achieve stability. The DUT shall be turned on first and operated for at least 30 mm prior to the measurement. Some display technologies may need a loop of colour patterns rendered on the screen during the warm-up period. Sufficient warm-up time has been achieved when the luminance of the test feature to be measured varies by less than ±3 % over the entire measurement period (e.g. uniformity measurements) for a given display image.
5.3.4 CondItions of measuring equipment
5.3.4.1 General conditions
Optical properties of displays shall generally be expressed in photometric or colorimetric units using the CIE 1931 standard colorimetric 20 observer (according to ISO/CIE 11664-1). Luminance can be measured by a photometer, and CIE tristimulus values (X, 1, Z) or CIE chromaticity coordinates by a colorimeter. A spectroradiometer can also obtain photometric and colorimetric values through a numerical conversion of the measured spectral radiance data (see for example [5]). The following requirements are given for these instruments.
The LMD shall be a luminance meter, colorimeter, or a spectroradiometer. For DUTs that have sharp spectral peak full-width-at-half-maximums (FWHM5) smaller than 20 nm, such as LCDs with fluorescent lamp backlights or LEDs with narrow-peak phosphors, quantum-dot phosphors, or narrow-spectrum OLEDs, a spectroradiometer should be used. A filter colorimeter should generally not be used for light sources with sharp spectral peaks, If a colorimeter is used, it shall be calibrated with the measured colorimetry values obtained from a narrow bandwidth spectroradiometer. Even with this procedure, the colorimeter will give lower accuracy results than the spectroradiometer. Report the characteristics of the spectroradiometer (as given in CIE 233) which is used for calibration. For light sources with sharp spectral peaks, the maximum bandwidth of the spectroradiometer shall be < 5 nm. In those cases, the wavelength accuracy shall be within ±0.3 nm. The spectroradiometer shall be capable of measuring spectral radiance over at least the 380 nm to 780 nm wavelength range, with a maximum bandwidth of 10 nm for smooth broadband spectra (i.e. broad spectrum with no sharp spikes).IEC 62977-2-1 pdf free download.IEC 62977-2-1 pdf free download.
