LMK Display Metrology Software & ADD-ONS


Software for pixel-level luminance measurements
DeMURA based on Advanced Pixel Registration
LMK DeMURA is a standalone software that offers an innovative way of assigning the luminance of each pixel to the correct position index using an LMK. It can either be used via a GUI in a Lab-environment or via TCP/IP in a production environment. Its heart is the Advanced Pixel Registration (APR) algorithm. Instead of switching-off neighboring pixels and measuring them individually as usually done, a high-density point cloud is used as a geometric registration pattern. This pattern is used to calibrate the position index of the specific setup and display. It thus includes all imperfections of the display and the imaging lens.

The aim of DeMURA is to correct the production-based pixel to pixel luminance and chromaticity variation.

Modern single-pixel emitter displays such as OLEDs, MicroLEDs, and LEDs suffer from production-related variations. The luminance and chromaticity can vary locally from pixel to pixel, resulting in a high-frequency non-uniformity and globally leading to a low-frequency non-uniformity. In order to correct these effects, the luminance data of individual subpixels need to be measured. Especially in a production environment, cycle time should be as low as possible.

Excerpt of a geometric registration pattern according to APR followed by DeMURA test measurement patterns at three different grey levels

APR improves the efficiency of the DeMURA measurement process massively. Instead of several images captures per grey level and color channel APR requires only one measurement for each tested grey level or color channel. Thus, DeMURA data can be either measured much faster, or on much more grey levels per color channel. The fastest way of APR would be our Single Shot Pixel Registration (SPR), which can be used in production under specific conditions. Here the registration pattern is only required when setting up the production control.