Curved OLED microdisplays

Abstract

Technical background for CMOS substrate thinning of CEA‐LETI (historically developed for through silicon via technology as well as for more recent activity to provide curved image sensors, for IR as well as for visible spectra) has been applied to realize curved OLED‐based microdisplays. It will be shown that test OLEDs made onto silicon wafers as well as 873 × 500 WVGA, 0.38″ diagonal, and an innovative 1920 × 1200 WUXGA, 1″diagonal, CMOS‐based microdisplays can be curved at R = 45 mm radius of curvature (1D) with no negative impact onto the circuit electrical characteristics. This feature can allow significant innovation on the system and application because it can help to redesign simpler and lighter optical engine systems, in the same manner as for curved image sensors. These results can be obtained owing to the integration of a new protective hard coat layer that has been used in conjunction with a robust thin‐film encapsulation to protect OLEDs from mechanical ingress (from process steps and handling) and oxidizing gas of the atmosphere, respectively. Results have been produced within the framework of the EU‐funded, H2020 project, called Large cost‐effective OLED MIcroDisplays (LOMID and their applications).

Emerging Biomedical Applications of Organic Light‐Emitting Diodes

“…However, the integration of OLEDs on silicon ICs renders it more difficult to obtain mechanically flexible devices even though extreme thinning of silicon allows to achieve a degree of mechanical flexibility. Integration of OLEDs on silicon is already used to make OLED microdisplays, [93,[263][264][265] some of which are bidirectional, e.g., to combine eye tracking and display function in optical viewfinders and smart glasses. [266] At the same time, this design flexibility of OLEDs represents challenges for the wider uptake of OLEDs in terms of system integration and manufacturing.…”

Recent progress of organic light-emitting diode microdisplays for augmented reality/virtual reality applications

“…In addition, the horizontal FoV of the AR device was improved to 43°using a high-aspect-ratio (32:9) OLED microdisplay with a laterally expanded pin mirror array, as shown in Figure 8(a). Another approach to reducing the form factor of an AR device is by using a curved display, which makes the optical system simpler and lighter [52,53]. To fabricate the curved OLED microdisplay, the mechanical grinding process was used [52].…”

“…Another approach to reducing the form factor of an AR device is by using a curved display, which makes the optical system simpler and lighter [52,53]. To fabricate the curved OLED microdisplay, the mechanical grinding process was used [52]. After grinding, the thickness of the OLED microdisplay decreased to 70-130 μm, even as the electro-optical characteristics of the OLED were maintained.…”

Variable Curvature Displays: Optical Designs and Applications for VR/AR/MR Headsets

“…Recently, it has been demonstrated that the approach used for the production of curved sensors [Lombardo(2019)] can be applied to create curved microdisplays thanks to the similarity between CMOS detectors and OLED (Organic Light-Emitting Diode) displays [Maindron(2019)]. This latest development opens new prospects for the creation of optical systems with curved focal surfaces.…”