Lectures

Light measuring devices (LMD) are essential tools for developing novel display technologies as well as for quality assurance in display mass production. More complex displays, e.g. Near Eye Displays (NED), might require various LMDs in different development and production phases.

Two-dimensional high-speed measurement of on-wafer. PhotoLuminescence and ElectroLuminescence and their single-pixel evaluation.

LIV curves are fundamental measurement of laser diodes to determine electrical and optical operating characteristics. LIV curves consist of L-I curves (optical intensity against current) and V-I curves (voltage against current). LIV curves determine power conversion efficiency, threshold current, slope efficiency, kinks, rollover point and more. LIV curves are widely used at various stages since it is critical to identify failed DUTs early in the manufacturing process.

The upcoming μLED display technology promises high contrast, fast response time, wide color gamut, low power consumption, and long lifetime. But, the technology is challenging for optical quality control, especially for narrow bandwidth μLEDs.

State of the art displays do have the ability to modulate refresh rate and duty cycle in order to save energy and to adapt to the display content. These features pose new challenges to display metrology equipment and may produce image artefacts. Here, we discuss the characterization and prevention of image artifacts due to the shutter type of the camera used for high accuracy display testing.

Near-Eye Displays covering a large field of view require complex optical imaging systems. While the optical system is designed to minimize distortion, residual distortion, material or production flaws lead to significant distortion. Imaging light measurement devices (ILMD) are used to detect distortion for product quality assurance. However, imaging measurement systems, especially with wide-angle lenses, may also add distortion to the measurement. Therefore, the calibration of ILMDs is crucial for the measurement of AR/VR device distortion. Here, we quantify and validate the accuracy of methods of distortion correction for an imaging light measurement device with a field of view of 120°.

Daily Poster Session from 6.00 pm - 7.30 pm

Visible and infrared light measurement devices (LMDs) are essential tools for developing novel extended reality display and sensing technologies as well as for quality assurance in the display and headset mass production. Extended reality devices come with a multitude of test requirements and the need to measure the same way as the human eye sees, and also might require different LMDs in the development and production phases.

In this EPIC Members New Product Release, our Product Manager Claudia Dippold will introduce Instrument Systems' latest CAS 140D IR spectroradiometer for measurements in the infrared range. It features the proven high measurement accuracy and reliability of the CAS140D series, recognized all over the world as a reference for wavelengths from 780–1700 nm. Compared to its predecessor model, the new CAS 140D IR offers significantly improved performance in signal sensitivity, stray light suppression and electronics.

Displays are becoming more and more prevalent in the automotive cabin and must serve a variety of functions flawlessly in a challenging environment. Specialized analysis to measure effects such as Black Mura must be conducted according to established standards; this enables meaningful comparison between supplier and manufacturer.

Vertical-cavity surface-emitting lasers (VCSELs) perfectly fulfill the requirements for present and future 3D sensing applications. However, to operate VCSEL-based devices in public, the manufacturer must assure “eye safe” operation compliant with the IEC 60825-1 standard or national equivalents. As VCSELs exhibit special emission characteristics that differ from other laser sources, the safety assessment is more complex, and a practical guideline does not exist.

Visible and infrared light measurement devices (LMDs) are essential tools for developing novel extended reality display and sensing technologies as well as for quality assurance in the display and headset mass production. Extended reality devices come with a multitude of test requirements and the need to measure the same way as the human eye sees, and also might require different LMDs in the development and production phases.

Next generation OLEDs displays have in principle endless contrast ratios due to their emittive nature. However, in practice OLED displays show non-uniformities at very low luminance which have to be measured and corrected in order to maintain constant contrast.

In this presentation, uniformity measurements at very low luminance will be presented and results from displays from a variety of manufacturers will be compared.

Next generation OLEDs displays have in principle endless contrast ratios due to their emittive nature and their ability to completely turn off pixels. This makes them ideal in applications that require low display luminance like use in dark/nighttime conditions.

Novel VCSEL arrays require spatial testing of the whole ensemble as well as of the single emitters in the near-field. Such optical measurements must be calibrated, corrected for polarization dependency and traceable to ensure minimum error budgets for eye safety evaluation.

Although VCSELs are intrinsically single-longitudinal mode devices, they usually show complex polarization characteristics. Most VCSEL are not designed to emit in a single polarization state, there is no control about the polarization angle. The light emitted by the VCSEL typically show a complicated polarization, even within one emitter and abrupt polarization switching can be observed when temperature or bias current is changed. In this presentation we show a method of measuring spatially resolved polarization characteristics of VCSELs. This is achieved using a combination of polarization filtered microscope optics and a CMOS camera.

Novel display technologies for AR/VR/MR devices require distinct tests to control quality during development and in production. Sharpness and contrast tests are particularly important due to the complex overlay of real and augmented images. Clear and immersive perception of the augmented or virtual reality requires optimal optical differentiation between different display contents. Typically, the modulation transfer function (MTF) acts a measure for sharpness and contrast. For accurate MTF measurement, an imaging test system should be based on a lens system that mimics the human eye system and have a similar-sized entrance pupil in front of the lens.

VCSEL-based sensor technology supports innovative applications. As VCSELs have special properties, in contrast to other typical laser sources, their characterization is more complex.

Near-eye displays (NEDs) exhibit a number of effects including distortion and sharpness distribution due to the optics that generate the virtual image. In his lecture, Dr. Cameron Hughes presents why a spectrally enhanced camera based system such as the LumiTop is ideal for fast and accurate production testing of these displays.

During the EPIC Members New Product Release, Instrument Systems' Program Manager Dr. Karthik Iyer presented our Nearfield VCSEL Testing Camera – VTC 4000.

Nowadays, the pandemic situation caused by the COVID-19 virus inspired many companies, research institutes and lighting designers to adopt UV radiation as a new tool in their projects and research. The promising germicidal effect of the UVC radiation also on the Coronavirus raises the question of the reliable measurement of the UV radiation. However, this complex task needs an expertise and appropriate equipment.

The upcoming μLED display technology promises high contrast, fast response time, wide color gamut, low power consumption, and long lifetime. However, the technology is not only challenging for mass transfer of the µLEDs from wafer to display, but also for massive parallelization of optical quality control at different manufacturing steps.

Superior properties of µLEDs for display applications challenge metrology with, e.g, narrow emission bandwidth and enormous wavelength variability depending on their electronic driving parameters. Therefore, we developed new imaging test solutions to make color uniformity measurements fast and highly accurate even for strongly varying spectral properties of µLEDs.

This short course will provide a fundamental understanding of display metrology and introduce measurement equipment and techniques. It is held in cooperation with Konica Minolta and Radiant Vision Systems.

Nowadays, the pandemic situation caused by the COVID-19 virus inspired many companies, research institutes and lighting designers to adopt UV radiation as a new tool in their projects and research. The promising germicidal effect of the UVC radiation also on the Coronavirus raises the question of the reliable measurement of the UV radiation. However, this complex task needs an expertise and appropriate equipment.

Novel display technologies for AR/VR/MR devices require advanced imaging systems to control quality during assembly and to calibrate the device. Such calibration yields an optimal match of left and right eye and allows color management for an accurate match of real world and virtual objects. For accurate measurement, such an imaging system should be based on a lens system that mimics the human eye system and have a similar-sized entrance pupil in front of the lens. Traditionally two approaches have been proposed:

Novel display technologies for augmented and virtual reality (AR/VR/MR/XR) devices, like Head-Mounted-Devices and Head-Up-Displays, require advanced imaging systems and calibration to control quality during assembly to accurately match the real world and virtual objects. We demonstrate and compare advantages of goniometric sampling spot measurements and camera based imaging solutions.

VCSELs have special properties in contrast to other typical laser sources. As a result, VCSEL eye safety evaluation is more complex and a couple of additional aspects have to be considered that would not apply for "normal" lasers. Consequently, the validation of a VCSEL's laser class is not trivial, and even more so because an easily understandable guideline for the assessment of VCSEL safety has not yet been published.

Date: December 2, 2020

Time: 17:15 (CET)

LpS Digital 2020

China International Optoelectronic Exposition

IEEE OGC Conference

Virtual Event

Friday, September 11, 2020

Photonics Germany @ CIOE 2020

Date: September 10, 2020

Time: 1 pm – 5 pm Shenzhen

Location: World Exhibition & Convention Center ∙ Conference Room 2, Hall 1

SID Display Week 2020, virtual event

Spatial Uniformity Display Measurement, Session 71.3

Thursday, August 6, 2020

SID Display Week 2020, virtual event

Display Measurement Standards I, Session 50.3

Thursday, August 6, 2020

edc 2020

Nuremberg, Germany

Wednesday, 26 February 2020, 16:35 - 16:55, Session 6 Display Glass & Measurements