In order to be successful in the home, micro-display technologies face significant challenges to displace conventional CRT solutions. Besides needing to offer a unique value to the end-user, micro-displays must be cost competitive and offer equivalent or better video reproduction performance. We will review our results in the basic requirements to succeed in the home environment. We have developed several technologies to advance DMDTM technology to meet those requirements including high speed interfaces that enable virtual elimination of color sequential artifacts, improved contrast, and package cost reduction.
We report experimental results on the evaluation of a sealing technique for organic light emitting diodes (OLEDs) used for high-resolution color microdisplay applications. Based on production and processing requirements for active matrix OLEDs (AMOLEDs) on silicon, the sealing process must protect the device against moisture and oxygen, not only during operation and storage but also during production. A conformal polymer/metal(oxide)/polymer multi-layer technology was selected for this purpose. AMOLED test structures were produced and tested with and without sealing under ambient conditions as well as in water. The applied sealing process was shown to be compatible with all steps of the OLED-based microdisplay production of eMagin Corporation. Our results confirm that encapsulating AMOLEDs with the described process leads to increased stability, both under operation as well as for storage purposes.
The response of a microdisplay device as a function of viewing angle is a major element in the quality of a microdisplay- based system. Such measurements are tricky and time intensive when realized with mechanical equipment. A new system, optimized for microdisplay and based on Fourier Optics is described. It realizes luminance and color coordinates measurement up to +/-30° with 0-360° azimuth angles in one shot (less than one minute) with a resolution better than 0.1 degree. This paper shows how characterization of the microdisplay itself, or combined with its illumination, can be performed for emissive, transmissive, reflective, on and off axis illuminated microdisplay devices. In particular, how its long working distance allows the equipment to carry out measurement even through beam splitter or complicated combination cubes is described. The new tool is shown to be adequate both for R&D and manufacturing teams.
A new solid state optical device technology - Electrically Switchable Bragg Grating (ESBG) technology - based on holographic polymer dispersed liquid crystal (H-PDLC), is being applied in Application Specific Integrated Lenses (ASILs) and Filters (ASIFs). These devices, also referred to as E-Lenses and E-Filters, are essentially stacks or laminates of intrinsically thin ESBGs encapsulated using transparent substrates. ASILs and ASIFs provide a basic colour sequential switching technology that directly challenges optical mechanical solutions such as color wheels. ASILs and ASIFs have no moving parts; they are completely solid state and silent in operation. They offer the benefits of holographic optical elements in terms of being able to compress conventional optical systems into compact and lightweight form factors. Since their switching speed is fast enough for colour sequential operation, colour dispersion can be controlled. They will have a major impact on the complexity and cost of a broad gamut of microdisplay applications, including projection and near-eye. The paper reviews the role of ASILs and ASIFs in both areas, with reference to design concepts currently in development.
Microdisplays offer a unique combination of small size, low power and high resolution. They are capturing particular attention in existing and developing applications, including camcorder viewfinders, digital camera viewfinders, head mounted displays, and cell phones. As the benefits of microdisplays become more visible, many companies are now facing a daunting task in scaling to mass production. Kopin Corporation’s CyberDisplay has been in mass production for over a year, and has had to overcome many challenges in the process. This paper provides some of Kopin’s perspectives in transitioning to mass production.
Taking advantage of the transient effect of Optically-Compensated Bend(OCB) cells, we have optimized the parameters of bend cells to be used as a reflective microdisplay, especially for a single-imager Liquid Crystal on Silicon(LCoS). The optimized configuration features an on-off response time of less than 0.5 ms for a 2 micron cell driven by ±3.5 V, which is sufficiently compatible with existing electronics. Such a LCoS display is an outstanding candidate for the field-sequential-color projection application, which we’re currently developing as a high-end target HD-TV with higher resolution of WUXGA(1,920x1,200) format.
Defect free homogeneous alignment of ferroelectric liquid crystals in the surface stabilized configuration remains challenging to obtain even over the relatively small area of liquid crystal on silicon microdisplays. The limitations of the conventional rubbed polymer alignment technique are discussed and the benefits brought by recent advances in backplane post-processing are demonstrated in realistic conditions. The potential of the linearly photopolymerized photoalignment technique are highlighted in terms of alignment quality, susceptibility to zigzag defects, and electro-optical performances.
The popularity of the Internet results in tremendous impact to our society. In this paper, we integrate state of the art technologies, such as image segmentation and multimedia transmission in the design and implementation of a networked control system. To illustrate the whole design concept, a test platform is established. The controlled end of the test platform includes I/O, A/D and D/A channels, and CCD cameras. The controller can be allocated at the other end on the Internet. We perform the developed real time image segmentation scheme in the controlled end to capture the trajectory of target object. This information is transmitted back to the controller end for further processing, and then the control signals are transmitted back to the controlled end. The proposed system architecture is of benefits in many areas, e.g., remote device control, intelligent home services, and visual surveillance systems.
The hardware resource limit and real time need have made it difficult to design embedded multimedia terminal’s software. We have designed and implemented a device’s software system. This device is a set-top box called SOPCA that can receive and play digital TV programs. In designing SOPCA’s software modules, we bring forward a scheduling method based on tasks. Each selfgoverned function is implemented in one task. And all SOPCA’s functions are achieved via these task cells’ coordination. This method boosts up system’s modularity, scalability and transplantability. It has some significance for other embedded systems’ designing.
Conventional stereo image coders employ disparity compensated prediction followed by the transform coding of the residual to encode the second image of a stereo pair. However, transform coders, such as DCT, are generally not efficient in coding the residuals. In order to improve the coding gain, subspace projection techniques have been proposed in literature . The idea is to apply a transform to each block, Rb, in the right image in such a way that it exploits stereo and spatial redundancy, simultaneously. The transformation is chosen to be a reduced order operator that projects block Rb onto a subspace that is spanned by a block dependant vector and a set of fixed vectors. Further to their work, we propose a novel local texture adaptive technique that selects between two sets of fixed polynomial vectors to improve the prediction. The choice of this adaptive technique was motivated by the distinctively different orientations of pixel value variation trends that are often present in natural scenes. Extensive experimental results indicate that the proposed technique outperforms the existing techniques both in terms of compression efficiency and reconstructed image quality. Particularly, the proposed algorithm performs well in natural scenes, where most stereo image compression techniques perform sub-optimally.
A new quality-scalable multichannel audio compression algorithm based on MPEG-2 Advanced Audio Coding (AAC) is developed in this work. The Karhunen-Loeve Transform (KLT) is applied to multichannel audio signals in the preprocessing stage to remove the inter-channel redundancy. Then, signals in de-correlated channels are compressed by using a modified AAC main profile encoder. Finally, a channel transmission control mechanism is used to re-organize the bit stream so that the multichannel audio bit stream has a quality scalable property when it is transmitted over a heterogeneous network. Experimental results show that, compared with AAC, the proposed algorithm achieves a better performance with the objective Mask-to-Noise-Ratio (MNR) measurement while maintaining a similar computational complexity at the regular bit rate of 64 kbit/sec/ch. When the bit stream is transmitted to narrowband end users at a lower bit rate, packets of some channels can be dropped and audio of full channel can still be reconstructed in a reasonable fashion.
Sprite coding for video content is a novel coding technique for low bit-rate compression applications. It has been used in MPEG-4 standard, which is a new generation coding standard of MPEG. But the bottleneck of usage of sprite coding in the real-time coding is the speed of global motion estimation because the speed of calculation of global motion estimation is too slow at present. The fast method of sprite coding is studied in the paper. A new fast and robust approach of global motion estimation is proposed. Compared to the traditional algorithm of global motion estimation, the new algorithm is much faster, and the estimated results are comparable. The global motion estimation is the most time-consuming process in the sprite coding for video, so to accelerate the calculation of global motion estimation will increase the speed of sprite coding. Thus the approach of sprite coding using the proposed global motion estimation is challenging in real-time video coding application. The technique of robust statistics and noise filter is introduced in the algorithm of improved global motion estimation. Some comparative experimental results about sprite coding are shown at the end of paper.
The luminance and the lifetime of new cathode-ray projection tubes, formed by YAG single crystal faceplates deposited with P53 or P53(Ga) phosphor powder, is investigated in this paper. Since the YAG faceplates have high thermal conductivity, the tubes can operate at high power density for long time. The experiments demonstrated that the lifetime of the YAG tubes have reached several thousands hours at high intensity. The cathodoluminescent efficiency of P53(Ga) phosphor is higher than that of P53 phosphor, but the maintenance of P53 phosphor is better.