Ultra high resolution imaging light measurement device for subpixel metrology of micro-LEDs and OLEDs

Abstract

More pixels! This is a major trend in the display industry. More (i.e. smaller) pixels with higher fill factors are urgently needed for near-eye applications such as VR goggles (using, e.g., microdisplays or pLED displays). With the displays so close to the observer's eye, screen-door effects and pixel nonuniformities are easily visible and disturbing for the consumer. Micro-LEDs or Micro-OLED displays feature pixel sizes < 10 pm and equally small pixel pitches. For both technologies each single subpixel is a light source itself. Luminance and color variations between the pixels are thus likely and strongly influence the visual quality of the display. This means quality control and subsequent calibration of the displays is crucial. Tests on subpixel level under the constraints of a production environment (esp. tact times), become necessary and are challenging.