Handheld Projector - Overview

Overview

Major advances in imaging technology have allowed the introduction of hand-held (pico) type video projectors. The concept was introduced by Explay in 2003 and shown to various consumer electronics players. Their solution was publicly announced through their relationship with Kopin in January 2005 The first public showcase was by Digislide at the ANZA tech conference in October 2006. Insight Media market research divided the leading players in this application into micro-display makers, e.g., TI's DLP, Himax, Micron / Displaytech and Syndiant LCoS, Maradin, Microvision, Lemoptix and bTendo MEMS scanners); light source makers, e.g., Lumileds, Osram, Cree LEDs and Corning, Nichia, Mitsubishi Lasers; and module makers, e.g., Jabil/Sypro Digital Light Processing (DLP) with LED, 3M Liquid crystal on Silicon (LCoS) with LED, Explay LCoS with laser. Manufacturers have produced handheld projectors exhibiting high-resolution, good brightness, and low energy consumption in a slightly larger format than pico. However, most LED projectors of the current pico size as of May 2009 have been widely criticized for having insufficient brightness for everyday use in a normally lit room.

In 2011, Texas Instruments DLP announced improved chip sets that enable brighter images. The chip sets are designed to enhance image brightness without increasing power usage for both WVGA (native DVD resolution) devices, such as mobile phones, and VGA devices, such as digital cameras and camcorders. The chip sets have the ability to project an image up to 50 inches (1270 mm) on any surface in optimum lighting conditions. The tiny projection chip requires very little space and is virtually undetected in a device's overall form factor. With advancements in size and performance, the TI DLP Pico chipset supplies big picture experiences with contemporary handsets..

There are currently three major competing imager technologies for micro projectors. Texas Instruments's Digital Light Processing (DLP), Microvision's beam-steering, and a handful of LCoS (Liquid crystal on silicon) manufacturers including Micron Technologies and Omnivision. Most micro projectors employ one of these imagers, combined with color-sequential (RGB) LEDs in either a single or triple architecture format. Manufacturers that have adopted this technology include Foryou MP-315(LCoS), Optoma's PK201 / PK301 (DLP), 3M's MPro 160 / 180 (LCoS), Aiptek's V50 (DLP), AAXA's M2 (LCoS), Bonitor MP302 (LCos), Micron's PoP Video (LCoS), and Vivitek's High Definition Qumi (DLP). Some older models incorporated a single LCoS imager chip with single white LED which is recognized to offer lower cost, high resolution, and fast response at the expense of color quality. Other models such as the Dell M109S employed a color wheel plus white LED technology which improves color quality but generally requires a larger form factor. Other micro projectors such employ RGB laser technology such as Microvision's beam-steering plus laser technology and AAXA's laser plus LCOS technology.

The advantages and disadvantages of each technology vary. For example, while DLP typically has slightly lower resolution than their LCoS counterparts due to the tiny mirrors used in DLP technology, 3-LED DLP projectors are generally regarded as having a higher contrast, better efficiency and lower power consumption as opposed color-sequential LCoS units and better color quality than white LED LCoS units. Laser scanning projectors such as Microvision's ShowX and AAXA's L1 offer very good color gamut and low power consumption due to the use of lasers as the light source and also present an image that is always in focus. However, high speckle noise along with thermal instability in the image remains a major challenge, primarily due to the pumped green laser. However, new "Direct Green Laser" (DGL) technologies that replace the "pumped green laser" in next generation Laser scanning projectors, in combination with improved hardware optics, MEMS Mirror designs and other operational methods are being deployed and under developement. Speckle noise should be reduced significantly, plus greatly improve thermal issues and reduce power consumption even further.

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