Uwe Lippmann

P‐174: Ultra Compact Projection System for Mobile Application

An ultra compact projection system for mobile application based on OLED microdisplay has been developed. This OLED projection system will be integrated into a wearable optical system like mobile phone or PDA. System design and realized prototype of the projection lens will be presented.

13.1: Ocular OLED-HMD with Simultaneous Eye-Tracking

For a lot of HMD application it is desirable to know where the user is looking at. For this purpose an ocular OLED-HMD system with collinear eye-tracking was developed. A viewing angle of 36° is realized in combination with an eye-tracker FOV of 20mm. The system is desired for medical applications.

Microdisplay-based industrial 3-D and microstructure measurement systems

— Microdisplays, whether they are of the liquid-crystal-on-silicon (LCOS) or organic light-emitting diode (OLED) type, have been, up until now, mainly used in multimedia applications or head-mounted displays. Due to their interesting possibilities, these displays open more and more alternative applications; for example, in optical metrology. Projection lenses for this application area need to be specially designed because the requirements on these systems differ completely from those for multimedia applications. The lenses must have very low geometrical image distortion and they have to be adapted to small objects and/or image distances. On the other hand, they often work with light sources with small spectral bandwidths; consequently, they do not need to be corrected for chromatic aberrations. In addition, the numerical aperture has to be large enough to collect and transfer as much light as possible, but also the size of the projection lens has to be as small as possible to ensure compact measurement systems. All these requirements lead to a compromise in optical lens design. Three optical system designs and realizations — one with an OLED microdisplay and two with an LCOS microdisplay — are presented.

System concept and optical design of miniaturized projection and imaging systems with OLED microdisplays

New projection concepts based on OLED (organic light-emitting diode)-microdisplays will be presented. Up to now mostly all projection systems are based on reflective and/or transmissive microdisplays like digital micromirror devices (DMDs), nematic liquid crystals displays (LCDs) or liquid crystal on silicon displays (LCOS). But the size of necessary light source and illumination optics is a strong limitation for the miniaturization of the projection system itself or for system integration. Here we propose to use a high-brightness OLED-microdisplay as active element for image or pattern generation, giving the possibility to realize compact projection or imaging units. Optical parameters of the microdisplays are determined to get input data for optical system design. Based on these experimental results specially adapted optical systems are designed. First prototypes and realized projection systems for applications in optical 3Dshape detection are presented.

Using the 3D-SMS for finding starting configurations in imaging systems with freeform surfaces

As the scientific field of the freeform optics is newly developing, there is only a small number of approved starting systems for the imaging lens design. We investigate the possibility to generate starting configurations of freeform lenses with the Simultaneous Multiple Surface (SMS) method. Surface fit and transfer to the ray tracing program are discussed in detail. Based on specific examples without rotational symmetry, we analyze the potential of such starting systems. The tested systems evolve from Scheimpflug configurations or have arbitrarily tilted image planes. The optimization behavior of the starting systems retrieved from the 3D-SMS is compared to classical starting configurations, like an aspheric lens. Therefore we evaluate the root mean square (RMS) spot radius before and after the optimization as well as the speed of convergence. In result the performance of the starting configurations is superior. The mean RMS spot diameter is reduced about up to 17.6 % in comparison to an aspheric starting configuration and about up to 28 % for a simple plane plate.

P‐172: OLED Based RGB‐Micro‐Projection System for Mobile Application

A micro-projector based on OLED micro-displays is presented. Three high brightness OLEDs, red, green and blue colored, are used to realize a full color imaging. The system design and the realized optical prototype of the projection lens are discussed.

Magnetically inert medical projection system with an image-guiding optical fiber

— A visual system for stimulating specific human brain functions inside a clinical magnetoencephalography (MEG) measurement chamber was developed. This system is based on a three-panel LCOS projection unit and uses a 4.5-m-long image-guiding optical-fiber bundle to transfer the image into the magnetically shielded MEG measurement chamber. In addition to a proper optical system design, special attention had to be paid to all materials used inside the magnetically shielded chamber. Here, no interfering fields due to electrics or ferromagnetic materials are allowed. The system concept, optical design, and the realized prototype are presented.

10.3: Projection System with an Image Guiding Optical Fiber Bundle for Picture Transfer

For stimulating specific human brain functions inside a clinical MEG measurement chamber a visual stimulation system was developed. This 3-panel LCOS projection system uses a 4 meter long image guiding optical fiber bundle to transfer the image into the magnetically shielded measurement chamber. System design and realized prototype are presented.