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With the development of display technology, several new displays have attracted much attention such as OLED display, QLED display, Laser display and Mini/MicroLED display. Displays with high brightness, wide color gamut, high efficiency and long lifetime are our ultimate goal. Defect inspections and color measurements are important for us to evaluate display quality. To obtain wide color gamut, we usually use narrow spectral bandwidth light source. However, it's not easy for traditional color camera or filter camera to measure narrow bandwidth light source because the accuracy is limited. In this paper, we simulate color measurement accuracy by color camera and filter camera. We analyze the influence of bandwidth effect on the color measurement and carry out bandwidth effect correction method. With the correction, the measurement accuracy improves obviously. In addition, different displays with different spectral bandwidth have been measured to validate the corrections. The results show significant improvement in color measurement accuracy. Our bandwidth effect correction can be used for wide color gamut display measurement.

The view angle characteristics refer to the changes in the luminance that occur with varying view directions which is defined as the luminance's view angle dependence (LVAD) in this paper. Recently the LVAD of OLED/LCD/miniLED/microLED panels attracts more attention. In this paper, the LVAD of OLED/LCD/mini LED/micro LED were measured and compared. For each panel, the LVAD of three gray levels and three colors at nine positions and four azimuth angles has been measured. The gray levels are 255/128/32, the colors are red (R), green (G), blue (B) and the azimuth angles are 0/90/180/270 degrees. It was found that the LVAD of OLED/miniLED/microLED changes a lot with colors except LCD panels. And the LVAD of all panels changes with the measurement azimuth angles. Gray levels will also affect the LVAD if different gray levels are with different spectra. Besides, OLED/LCD/miniLED panels exhibit the same LVAD at different positions.

To decrease tack time during Demura process, images are captured directly after turning on panels or changing patterns and then used to generate compensation data which determines the Demura results. However, the panel's luminance stability in those situations have not been paid enough attention. Seven panels from five different OLED panel producers were tested at various situations which are from turning off to turning on the panel, changing patterns from different gray levels of the same color or from the same gray level but with different colors. Even after the panels were turned on for a while, their luminance is still instable, therefore luminance's stability was also tested. We found that when turning on panels or changing patterns from different colors, the luminance will go up or down 1–5% of the mean of the relatively stable luminance and need 4–30 seconds to get stable. However, when changing patterns among different gray levels but with the same color, there almost no luminance's sudden change at high gray level (above 160) while the luminance goes up or down 0–3% and need half time to get stable at low gray level (32). The results provide a choice to avoid the sudden change of panels' luminance when changing patterns during Demura process while not increasing the tack time so much and also a possible reason that why the Demura results are not good enough. We also found that the luminance instability could be 0–4% at high gray level (RGB192) and 0.3–4.9% at low gray level (RGB32) which should be paid enough attention since the compensation data based on only one image could not be accurate enough if the panels' luminance is not stable.

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