Important display performance criteria such as luminance, color or contrast may or have to vary over the viewing angle. An LMK equipped with a conoscopic lens (also called hypercentric lens or fourier lens) can measure the viewing angle characteristics within one shot from a small surface area. The conoscopic lens can also be used for viewing angle measurements of other light sources and – thanks to its external entrance pupil - the characterization of Near-to-Eye displays (NED) with virtual images.

The LMK Conoscope is a software add-on designed for using the LMK with our conoscopic lenses. The add-on ensures that the geometrical information of the specific conoscopic lens is used to map the angular coordinate system in the camera images.

It features:

  • A point-by-point evaluation of viewing angle characteristics within the polar coordinate system ϑ and φ of the device under test (in degree)
  • A point-by-point evaluation of viewing angle characteristics in the horizontal and the vertical viewing angles ϑH and ϑV of the device under test (in degree)
  • Automatic generation of the angular OEM regions A+, A and B in both coordinate systems for the evaluation of automotive displays according to the OEM specification.
  • Generation of arbitrary evaluation regions and storage for later use

 

Bild8.png

Color over angle measurement of a LCD in dark state: Photograghic image (left) and measurement result (right)

To learn more about our conoscopic lenses, other measurement application or our automated alignment system LMK Position, which simplifies the alignment of the conoscopic lenses espacially for complex geometries, please click on the links and references shown below.

RELATED PRODUCTS

Conoscope lenses

Conoscope lenses
LMK Position

LMK Position

High-speed and high-precision alignment for display metrology

Publications

International Conference on Display Technology (ICDT 2021)

The alignment quality and reproducibility in ILMD (Imaging Luminance Measurement Device) based display metrology has a great influence on the reproducibility of the obtained measurement data. In this context, this contribution outlines and introduces several advanced measurement and alignment concepts that can be performed with “photometric robotics”. The term describes machine vision performed with an ILMD supported by robotic movements.
Authors: I. Rotscholl; B. Liu ;U. Krüger
Advanced Alignment and Metrology Concepts Using Photometric Robotics with Examples for Automotive Displays

SID Vehicle Displays & Interfaces 2021

With increasing performance parameters and decreasing costs OLED displays are getting more relevant for premium automotive application. Therefore, the German Flat Panel Forum (DFF) extends its current LCD specification and measurement methods to also cover OLED displays. Challenges and solutions for lifetime, Burn-In (Image Sticking) and viewing angle procedures are presented more in detail.
Authors: K. Blankenbach; F. Bhatti; M. Stuetzel; M. Pohl; S. Proemmel; I. Rotscholl; O. Bader; D. Schaffer

electronic displays Conference 2016

Measurements with conoscopic lenses together with ILMDs (Imaging Luminance/Color Measuring Devices) can support the characterisation of displays and materials during the R&D and production process. Using a conoscopic lens the angular dependence of luminance/color can be measured with only a single measurement. Using different geometrical relations between the device under test, the conoscopic lens and different illumination conditions a lot of display and material properties can be measured with one or a few measurements only. The article shows the working principle of conoscopic lenses in detail. Furthermore the measurement of the angular dependent luminance/color, the angular dependent contrast and the measurement of selected angular dependent material properties (e.g. transmission and reflection characteristics of glasses) are presented. For all applications the advantages and limitations of the conoscopic lens measurements are explained to suggest the right fields of application for this measurement method.
Authors: U. Krüger; F. Schmidt

International Conference on Display Technology (ICDT 2019)

This contribution aims to describe the challenges associated with the characterization of NED (Near-Eye Displays) using Imaging Luminance and Color Measuring Devices. Based on the special attributes of NED systems, the requirements for the measurement set-up are deduced. Then two special lens designs, the hypercentric lens and the front stop lens, which both overcome these challenges, are introduced. This includes their concepts, applications and presentation of exemplarily obtained results.
Authors: B. Liu; T. Porsch; N. Schuster; I. Rotscholl; U. Krüger
Special Lenses for Measurement of Near Eye Displays (NED)

SID International Symposium 2016

The requirements of automotive displays differ to a large extent from consumer and industrial displays. In order to reduce the effort in specifying and evaluating high quality displays, German automotive OEMs, Tier 1/2 and the German Flat Panel Forum have launched a cooperation.
Authors: K. Blankenbach; U. Krüger; H. Lauer, M. Zobl
Invited Paper: Recent Standardization Efforts and Measurement Procedures of German Automotive OEM and German Flat Panel Forum (DFF)
Type:
Add-On
Applications:
Automotive Aviation Display
Measurands:
Color measurement Light measurement
Tasks:
Automation & Industry Development & Industry Science & Research