Smart pixels

An x-ray area detector can be used to collect the intensities of many reflections at a time. The crystal must be oriented in many different settings with respect to the incident beam but the detector needs to be positioned at only a few positions to collect all of the data. A charge coupled device (CCD) is used as the area detector on the Siemens SMART single crystal diffractometer system. The SMART detector consists of a flat 6-cm circular phosphorescent screen that converts x-ray photons to visible light photons. The screen is coupled to a tapered fiber optics bundle which is then coupled to a one inch by one inch square CCD chip. The CCD chip has 1024 x 1024 pixels each of which stores an electrical charge proportional to the number of... 

Figure 11.10. NW smart pixels, (a) Schematic of an integrated crossed NW FET and LED and the equivalent circuit, (b) Shows SEM image of a representative device, (c) Plots of current and emission intensity of the nanoLED as a function of voltage apphed to the NW gate at a fixed bias of -6V. (d) EL intensity versus time relation when a voltage applied to NW gate is switched between 0 and +4V for a fixed bias of -6V. [Reprinted with permission from Ref. 59. Copyright 2005 Wiley-VCH Verlag.]...

The dual-function utility (photon emission in forward bias and photon detection in reverse bias) can be employed to fabricate smart display matrices [148]. By presetting the device in the photodetecting mode (zero or reverse bias), each pixel can sense an optical signal and transfer that signal to the memory in the driving circuit, similar to the process in a photodiode... 

A Dodabalapur, Z Bao, A Makhija, JG Laquindanum, VR Raju, Y Feng, HE Katz, and J Rogers, Organic smart pixels, Appl. Phys. Lett., 73 142-144, 1998. 

The first demonstrations of using OTFTs to drive OLEDs came from independent groups at Bell Laboratories and Cambridge University nearly simultaneously in 1998 [41,42]. These were single smart pixels, each incorporating one polymer-based OTFT and one OLED. Since AMOLED displays require at least two TFTs per pixel, these demonstrations were not examples of complete AMOLED pixels. 

Rogers. J. A., Z. Bao, M. Meier, A. Dodabalapur, O. J. A. Schueller, and G. M. Whitesides. 2000. Printing, molding, and near-field photolithographic methods for patterning organic lasers, smart pixels and simple circuits. Synth. Met. 115 5-11. 

FIGURE 1 Example of an element (pixel) of a smart pixel array. [Reprinted by permission of SPIE—The International Society for Optical Engineering, Neff, J. A. (1996). Review on the Status of Optical Interconnect Technology, Proceedings of Materials, Devices, and Systems for Optoelectronic Processing 2848, p. 106-117.]... 

FIGURE 6 Two packaging approaches for hybrid GaAs/Si smart pixels, (a) Both chips flip-chip bonded side-by-side on a transparent substrate with interchip electrical connections provided by metal conductors patterned on the substrate, (b) One chip flip-chip bonded to the other, followed by substrate removal. 

FIGURE 8 Three-dimensional parameter space characterizing smart pixel arrays. [Courtesy of Ravi Athale. Reprinted by permission of Wiley—Liss, a subsidiary of John Wiley Sons, Inc., Neff, J. (1997). In Optoelectronic Packaging (A. R. Mickelson, N. R. Basavanhally, and Y. C. Lee, eds.), John Wiley Sons, New York.]... 

Table I classifies smart pixels according to five levels of functionality. Each of these five levels is characterized by its number of transistors per pixel, its pixel density, typical functionality achievable with its given number of transistors per pixel, its advantage (as compared to the other levels), and some characteristic applications. In order to avoid considerable replication, lower-level pixel functionalities are not repeated at the higher levels, but should be considered as included.

Abbreviations OE, optoelectronic DRAM, dynamic random access memory I/O, input/output ATM, asynchronous transfer mode VLSI, v y large scale integration ASIC, application-specific integrated circuit. [From Pinkston, T. M., and Kuznia, C. (1997). Smart-Pixel-Based Netwa-k Interface Chip, App/. Optics 36(20), 4871-4880.]... 

It would be unreasonable to list all activity in SPA fabrication. Table II lists what the author judges to be the most significant recent activity of the research groups that have been most active in the noted categories of smart pixel research. It should be noted that the SPA sizes and complexities are cited for the purpose of giving the reader a feel for the relative maturity of the technology. They should not be used to compare one SPA development organization to another since the SPA... 

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