This PDF file contains the front matter associated with SPIE Proceedings Volume 6489, including the Title Page, Copyright information, Table of Contents, Introduction (if any) and the Conference Committee listing.

One major issue in microdisplay-based projection television has always been the need for more light. Without sufficient amount of light, the screen gain is usually the final parameter that is adjusted to produce acceptable on-axis brightness. As a result, one major disadvantage of rear projection television (RPTV) is narrow viewing angle when compared with other display technologies. Traditional reflector systems, including elliptical and parabolic reflectors, perform well in most cases, but are inefficient for smaller etendue values corresponding to smaller image panels. The common remedy is to make lamps with shorter and shorter arcs to increase the coupling efficiency, but the corresponding lifetime of the lamps are reduced and most of the time, these short arc lamps can only operate at low power, thus limiting the total output of the illuminating system. The Dual Paraboloid reflector (DPR) technology allows the use of higher power lamps while maintaining long life, thus allows wider viewing angles to be achieved. In addition, low power lamps when used with the DPR system allows such a long life operation that lamp replacement is not needed, allowing the RPTV to compete effectively with LCDTV and PDP systems. These advantages are also applicable to front projectors with long life lamps that lower ownership costs.

A general theory on light-pipe/tunnel-based recycling schemes, along with some experimental data obtained from LED illuminators, is presented in this paper. Light recycling is classified as angular, spatial, or mixed based on the angular filtering characteristics of the recycling process. The principles behind the three schemes are analyzed and some experimental results are presented at the end.

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.

In the past few years the microdisplay-based projection television market has been quickly spreading over what used to be the domain of CRT technology. The demand for larger display sizes and improved image quality, together with more accessible pricing is aggressively driving the transition to microdisplays. The screen is the component of the projection system that directly conveys the visual information to the user, responsible for distributing the luminous energy from the light engine. However, the projection screen is far from a simple diffuser and today's performance requirements for display systems require sophisticated screens to meet the resolution, transmission efficiency, and contrast required by visual displays.

Due to Light Emitting Diode (LED) have the properties of compact size and high efficiency, there have more and more illumination system use it to be a lighting source. In this paper, a compact projection system was designed by a simple architecture. For this compact projection system, the prototype has been developed by using a single tranmissive light valve and LED source in it. With a simple collecting light reflector, a curved mirror and a light tunnel of the illumination system, the optical efficiency from the source to light valve is up to over 70% and the uniformity illuminated on the light valve is over 85%.

New laser-based light sources are highly desired for projection displays because of the need for longer lifetime, lower etendue, and higher color gamut. High power, frequency doubled red, green and blue (RGB) surface emitting diode laser arrays have been developed for use in low cost projection microdisplay television, digital cinema and pocket projectors. Single green lasers for pico-projectors using MEMS scanners have also been demonstrated.

This paper will present the development of a new driver board for the Texas Instruments Discovery^TM 3000 Micromirror Device (DMD) chipset being offered by Texas Instruments. A requirement of our current research is to have a real-time digital interface to a reflective spatial light modulator to project patterns based upon images obtained via a camera system. As a result, we developed the DVimage^TM spatial light modulator driver board based upon the Texas Instruments Discovery^TM 3000 chipset. The DVimage^TM can be run from any computer through the standard DVI port, can display 8-bit grayscale at 60Hz in real-time and can store 4600 full resolution 1-bit images on the board and display them at a maximum frame rate of 16,300 fps. The board also has programmable sync pins to trigger other systems (e.g. light sources, cameras). An SDK and software examples have been developed to allow for integration into custom applications. This paper will describe the general hardware architecture and software tools along with example applications for this spatial light modulator system.

Head-mounted projection display (HMPD) technology, as an alternative to conventional head mounted displays (HMD), offers the potential of designing wide field-of-view (FOV) optical see-through HMDs. Due to multiple passes through a beamsplitter, however, existing HMPD designs suffer from low luminance efficiency and thus the displayed image is lack of brightness and contrast. The design of a polarized head-mounted projection display (p-HMPD) was recently proposed. The major departure of a p-HMPD design from other existing HMPD systems is the usage of polarization management to minimize light loss through beamsplitting. A p-HMPD consists of a pair of projections lenses, microdisplays, polarization control elements, and retroreflective sheeting material as a projection screen. In this paper, we explore the usage of a ferroelectric liquid-crystal-on-silicon (FLCOS) microdisplay as the image source and present a compact design of an illumination unit with double telecentric optics to achieve highly bright and uniform illumination on the FLCOS microdisplay. The key contribution of this design lies in the compactness which is a critical factor in HMD systems. The first-order optics and the transformation of polarization in the design will be described in detail. The simulation of the illumination unit will be shown and its luminous efficiency and uniformity will be discussed. Based on this illumination engine, we will further describe the design of a compact projection lens and discuss the overall performance of the optics.

We present a projection optical system incorporating a dynamic optical element and we outline some of its potential applications for digital projection displays. We describe experiments undertaken to validate one of these applications, the correction aberrations in a rear-projection television (RPTV) optical module where the original fold mirror is replaced by a simple MEMS deformable mirror.

Silicon micro machining once headed into two directions: MEMS (micro electro mechanical systems) based sensors like accelerometers and gyroscopes on the one hand, MOEMS (micro opto electro mechanical systems) based actuators like scanner mirrors on the other hand. Now both directions meet again: A tilt compensated projector module uses a two dimensional excited scanner mirror as well as accelerometers and gyroscopes. The projector module can have a minimum size of 30 x 15 x 15 mm³ with a monochrome red laser source (λ = 635 nm). It reaches a resolution of 640 x 480 pixels (VGA) and a frame rate of 50fps. Colour projection requires lager size due to the lack of compact green laser sources. The tilt and roll angles are measured statically by a three axes accelerometer, fast movement is detected dynamically by three single axis gyroscopes. Thus tilt of the projection systems was compensated successfully. The dynamic range was set to 300 x 300 pixels for sufficient system dynamic. Furthermore the motion detection was used to achieve control and input device functions. The first demonstration and test system consists of a projector mounted at the axis of a PC racing wheel together with the additional inertial measurement unit (IMU) system. It was shown that projection and input function work well together. Using this approach, new possibilities for hand-held devices arise in the close future.

We present a compact light emitting diode (LED) based projection system with potential for stereoscopic viewing. The optical core consists of four polarizing beam splitters (PBS), positioned in a cross configuration, with wavelength selective half wave plates placed between them. Four liquid crystal on silicon (LCoS) panels are located at the exterior facets of two PBSs in opposite corners of the cuboid. The illumination system combines individual LED sources and ensures telecentric illumination through the optical core. This architecture gives rise to two light paths that independently generate two linear polarized images with orthogonal polarization direction. When the observer wears polarization sensitive eyeglasses and a polarization maintaining screen is used, each eye will see a different projected image such that three-dimensional (3-D) viewing can be perceived. On the other hand, 2-D vision is possible by projecting two identical images.

In this work we propose a technique to measure micro displacements using Moiré patterns of Fresnel zone plates films. In this technique the pattern is placed on a mechanical mount and the displacements are measured counting the displaced fringes of an amplified moire image as the mount is moving.

Highly efficient transmissive spatial light modulators are the key components of laser and LED projection displays. Collimated and spatially coherent laser light provides new possibilities in projection imaging by extended depth of focus and using microlens arrays. We present a method for investigation of microlens arrays, which reduce lateral dimensions of a light beamlet passing through each pixel of a spatial light modulator, down to dimension of micro-diaphragm that is created by TFT layer. In this method we exploit physical optics propagation combined with geometrical ray-tracing for both minimizing a diffraction spread and accounting for aberrations of each lenslet. It is mainly useful for designing and characterization of MLA with relatively high numerical aperture and complicated surface shape of each lenslet. Modeling the MLA enabled to predict such MLA parameters as focal spot size, longitudinal variations of spot size, transmission efficiency for given clear aperture of each pixel, output divergence of the cross talk between adjacent pixels and its minimization. Simulation data on combined effect of aberrated geometrical defocusing and diffraction spread is presented. Simulated spherical and elliptical lenslet shapes were used as a base for designing advanced spatial light modulators with high diffraction efficiency.

A display system requiring no special glasses is a useful technology for 3D images. The rear projection lenticular 3D display system using a projector has superior characteristics, such as having a large screen with wide field of view. However, a conventional system has disadvantages such that the observer perceives reverse images when he views a left image by his right eye and vice versa. To solve this problem, this paper describes the technique of making invisible area using a polarized slit barrier. Using this technique, we propose the 3D display using polarized slit for elimination of pseudoscopic viewing area to solve the pseudoscopic image problem. Moreover, we describe a development of new system for displaying 4-views images. This is the stereoscopic display with the 4-views using the combination of a parallax polarized slit and cylindrical lenses. It is possible that the image resolution of each view is reduced both horizontally and vertically using this combination. This 4-views stereoscopic 3D displays can avoid the horizontal resolution problem of conventional system.

This paper describes the field-lens display for viewing the 2-views stereoscopic images. Conventional 3D movie systems with the special glasses such as polarized glasses provide us touchable spatial images. However, these 3D imaging systems require the observer to wear the glasses. Our research group would like to realize the glasses-less 3D imaging system to construct an interactive spatial imaging environment. The authors have researched the 3D displays and applications. We have ever proposed 3D displays using the slit as a parallax barrier, the lenticular screen and the holographic optical elements(HOEs) for displaying active image^1,2,3. We have developed field-lens 3D displays using dual LCD panels for displaying full-screen left and right images. This system consists of the user's position detection system and the spatial imaging system. Our proposed method can ever modulate horizontally and vertically oriented linear polarized illuminations. However, each LCD panel can't display a left or right image directly. To solve this problem, this paper proposes new modulation method using both linear and circular polarizations.

Today, there are many kinds of 3D displays used to produce 3D images but these 3D images are not touchable. Therefore many researchers study how to produce a floating image from 3D image. In floating image display, a large concave mirror or a large lens is used to produce the floating image. However the lens and the concave mirror produce the defected image because magnifications of these two elements are not constant, and an image distance is not linear relationship from an object distance. In this paper we present the stereoscopic floating image system using a stereo display and two lenses. The proposed floating display system provides an impressive feel of depth, and produced image appears to be located in a free space and near the observer. The two-lens system can eliminate all defects of large convex lens because the magnifications are constant and are not related the object distance and the image distance. The experimental result shows that the proposed system successfully makes a touchable stereoscopic floating image.