Uwe Mackens

Blue diode pumped solid-state lasers for digital projection

Lasers present many advantages over currently used light sources for projection applications. Compact as well as efficient displays can be realized with RGB laser systems. The extreme brightness and collimation of lasers enable very efficient light collection. For portable, battery-powered microprojectors or even integrated devices, where the efficiency becomes even more critical, 50 mW per color is enough for a luminous flux on the projection screen of 20 lm. While blue and red diode lasers in this power range are becoming widely available, the bottleneck for this application is still the lack of integrated green laser sources. We present here a blue-diode pumped Pr3+-doped LiYF laser emitting at 523 nm. By optimizing on many aspects of the crystal and resonator, we increased the laser output power up to 169.4 mW, which corresponds to a total power conversion efficiency of 7%. Moreover, lasing in red can be obtained with the same crystal with similar or even better output powers. This makes the Pr:YLF laser an ideal candidate for an RGB projection source together with blue InGaN diodes.

Ferroelectric thin films for integrated passive components

Abstract Miniaturisation and integration of passive components play an important role in todays components market. It can be achieved by applying thin-film technologies for capacitors, resistors and inductors; high component densities have been realised with ‘Passive Only Networks’. The dielectric materials used for integrated thin-film capacitors ranging from Si3N4, Ta2O5, TiO2 to earth alkaline as well as lead perovskite layers are reviewed. The capacitor performances including temperature stability, insulation resistance, breakdown fields and endurance are discussed as a function of material composition.

Sol-gel and mod processing of layered perocskite films

Abstract Sol-gel and MOD processes have been used to deposit layered perovskite films such as Bi4Ti3O12, SrBi2Ta2O9 and SrBi2NbTaO9 films on top of Si(100) substrates with Ti/Pt electrodes. Their structural and electrical properties have been studied as a function of processing. Additionally sol-gel and MOD processes have been applied for SrTiO3 films. The morphology of the layers has been characterised and compared with the morphology of layered perovskite films.

Solid‐state lasers for projection

— The unique advantage of projection displays is the ability to produce large images from small devices. The use of lasers as the projection light source will mean a further step in terms of compactness as well as efficiency for projection systems. However, the advent of laser projection is currently still limited by the availability of low-cost green lasers. Blue-diode-pumped solid-state lasers are one promising way to realize green as well as red lasers that are specifically suited for projection applications. An efficient solid-state laser that is based on Pr3+:YLF as the laser material, pumped by a blue-laser diode and emitting at 523 nm, is presented here. The laser reaches power-conversion efficiencies of more than 7% and output powers of up to 378 mW at green wavelengths. By making only minor modifications to the laser resonator, a red laser emitting at 640 nm can be realized within the same setup. An output power of 166 mW at a power-conversion efficiency of 6.9% is demonstrated in the red. By combining a red- and a green-emitting blue-diode-pumped solid-state laser with another blue diode, an integrated RGB projection light source can be realized that is based on a single-diode technology.

Structural and electrical characterization of PZT and PLZT films grown on spin-on processed conductive oxide electrodes

Abstract A spin-on processing technique has been developed to grow conductive oxide electrodes e.g. RuOx as well as stacks composed of conductive oxide electrodes and PZT or PLZT on top of Si (100) substrates. The electrical properties of the PZT and PLZT thin films were characterized and compared with films grown on standard Ti/Pt electrodes.

47.2: Solid-State Lasers Emitting at Red, Green and Orange Wavelengths for Projection Applications

Lasers will bring a further step in terms of compactness and efficiency for projection systems. However, the availability of suitable green laser sources limits the advent of laser projection. Blue diode pumped solid-state lasers are presented here as one promising way to realize green, red and orange lasers that are specifically suitedfor projection applications.

Power-scaling of blue diode pumped solid-state lasers for the visible wavelength range

Lasers as light sources for projection applications provide several advantages: Compact as well as efficient displays can be realized by using lasers. With only 200mW in every primary colour a luminous flux of 100lm on the screen is achievable from a small device [1]. However, the bottleneck for this application is still the lack of integrated green laser sources. Especially blue diode pumped solid-state lasers, where for example a Pr:YLF-crystal is pumped by a GaN-laserdiode, have recently gained a lot of interest for such applications.

14.3: Ujoy Technology for Personal Projection

Personal projectors are compact and affordable devices used for gaming, entertainment or photo projection. A very bright light source is at least as important as for standard front projectors. The new 50W Ujoy lamp system with 1mm arc enables efficient projection systems with a screen brightness of 200–300lm. Lower cooling requirements, the potential for battery operation and the low voltage input makes it the ideal source for this new category of projectors.

Personal projection with Ujoy technology

Personal projection is a new way to use projectors for gaming, entertainment or photo projection. The requirements for this new category have been defined based on market research with focus groups. A screen brightness of 200-300lm out of compact and affordable devices is a must. In order to reach this performance a very bright light source is at least as important as for professional projectors. The new 50W Ujoy lamp system with 1mm arc enables efficient projection systems. Lower cooling requirements, the potential for battery operation and the low voltage input makes it the ideal source for this new category of projectors.

Invited Paper: UHP‐lamp systems for projection applications

— Projection systems have found widespread use in conference rooms and other professional applications during the last decade and are now entering the home-TV market with considerable pace. Projectors as small as about one liter are nowadays able to deliver a screen flux of several thousand lumens and are, with a system efficacy of more than 10 lm/W, the most-efficient display system realized today. Because such highly efficient projectors employ microdisplays as light valves, short-arc lamps are a key component in realizing these properties. The introduction of the UHP-lamp system by Philips in 1995 can be identified as one of the key enablers for the commercial success of projection systems. The ultra-high-performance (UHP) lamp concept features outstanding arc luminance, a well-suited spectrum, long life, and excellent flux maintenance. For the first time, it combines a very-high-pressure mercury-discharge lamp having an extremely short and stable arc length with a regenerative chemical cycle that keeps the discharge walls free from blackening, leading to lifetimes of over 10,000 hours. In this review, the most important aspects of the UHP concept that enabled its success in the projection market are described, followed by a discussion of some recent additions to the UHP-product portfolio.