A digital imager apparatus uses the differences in absorption length in silicon of light of different wavelengths (400-490nm, 490-575nm, 575-700nm) for color separation. A preferred imaging array (102, 104, 106) is based upon a three-color pixel sensor using a triple-well structure (100). The array results in elimination of color aliasing by measuring each of the three primary colors (RGB) in each pixel in the same location.

Color separation in an active pixel cell imaging array using a triple-well structure

A vertical color filter detector group according to the present invention is formed on a semiconductor substrate and comprises at least six layers of alternating p-type and n-typed doped regions. PN junctions between the layers operate as photodiodes with spectral sensitivities that depend on the absorption depth versus wavelength of light in the semiconductor. Alternate layers, preferably the n-type layers, are detector layers to collect photo-generated carriers, while the intervening layers, preferably p-type, are reference layers and are connected in common to a reference potential referred to as ground. Each detector group includes a blue-sensitive detector layer at an n-type layer at the surface of the semiconductor, a green-sensitive detector layer at an n-type layer deeper in the semiconductor, and a red-sensitive detector layer at the n-type layer deepest in the semiconductor. The blue-sensitive detector layer at the surface of the semiconductor may have a reference layer only below it, while the red- and green-sensitive detector layers have reference layers above and below them. Three sets of active pixel sensor circuitry are coupled to the three detector layers, such that three active pixel sensors are formed using the group of three co-located detectors of the vertical color filter detector group.

Vertical color filter detector group and array

In vivo dosimetry (IVD) has been used in brachytherapy (BT) for decades with a number of different detectors and measurement technologies. However, IVD in BT has been subject to certain difficulties and complexities, in particular due to challenges of the high-gradient BT dose distribution and the large range of dose and dose rate. Due to these challenges, the sensitivity and specificity toward error detection has been limited, and IVD has mainly been restricted to detection of gross errors. Given these factors, routine use of IVD is currently limited in many departments. Although the impact of potential errors may be detrimental since treatments are typically administered in large fractions and with high-gradient-dose-distributions, BT is usually delivered without independent verification of the treatment delivery. This Vision 20/20 paper encourages improvements within BT safety by developments of IVD into an effective method of independent treatment verification.

In vivo dosimetry in brachytherapy

Recent developments in handheld and portable optosensing-a review.

In the two centuries of photography, there has been a wealth of invention and innovation aimed at capturing a realistic and pleasing full-color twodimensional representation of a scene. In this paper, we look back at the historical milestones of color photography and bring into focus a fascinating parallelism between the evolution of chemical based color imaging starting over a century ago, and the evolution of electronic photography which continues today. The second part of our paper is dedicated to a technical discussion of the new Foveon X3 multilayer color image sensor; what could be descried as a new more advanced species of camera sensor technology. The X3 technology is compared to other competing sensor technologies; we compare spectral sensitivities using one of many possible figures of merit. Finally we show and describe how, like the human visual system, the Foveon X3 sensor has an inherent luminancechrominance behavior which results in higher image quality using fewer image pixels.

/pdf/eyeing-the-camera-into-the-next-century-2vvdvzfn02.pdf

Eyeing the Camera: Into the Next Century*

We propose a novel configuration of linearized subthreshold operational transconductance amplifier (OTA) for low-power, low-voltage, and low-frequency applications. By using multiple input floating-gate (MIFG) MOS devices and implementing a cubic-distortion-term-canceling technique, the linear range of the OTA is up to 1.1 Vpp under a 1.5-V supply for less than 1% of transconductance variation, according to testing results from a circuit designed in a double-poly, 0.8-/spl mu/m, CMOS process. The power consumption of the OTA remains below 1 /spl mu/W for biasing currents in the range between 1-200 nA. The offset voltage due to secondary effects (contributed by parasitic capacitances, errors and mismatches of parameters, charge entrapment, etc.) is of the order of a few ten millivolts, and can be canceled by adjusting biasing voltages of input MIFG MOS transistors.

Wide-linear-range subthreshold OTA for low-power, low-Voltage, and low-frequency applications

A photodetector based on buried junctions includes a semiconductor structure with two successive p-n junctions, buried at increasing depths, assembled in pairs in opposition, and defining at least three layers. One of the layers is adjacent to a photosensitive portion of the surface of the photodetector. A reverse bias is applied to the junctions, and the values of at least two internal currents passing through such junctions is detected. The internal currents are generated by received light, with each of the junctions corresponding to a particular wavelength of the received light.

Photodetector based on buried junctions and a corresponding method of manufacture

The quality insurance in radiotherapy in the frame of highly complex technical process as Intensity modulated radiotherapy (IMRT) needs independent control of the delivered dose to the patient. Actually, up to now, most of the radiotherapy treatments rely only on computed dosimetry through a rather complicated series of linked simulation tool. This dosimetry approach requires also qualified treatment means based on cautious quality insurance procedures. However, erroneous parameters could be difficult to detect and systematical errors could happen leading to radiotherapy accidents. In this context, in vivo dosimetry has a critical role of final control of the delivered dose. As many beam incidences and ports are used for any photontherapy treatment, external control could be very tedious and time consuming. Therefore, innovations are needed for in vivo dosimetry to provide ergonomic and efficient tools for these controls. This paper presents a review of technologies and products that can be used for in vivo dosimetry. It proposes also a reflection on the concepts to develop future devices suitable for this purpose. The technical means with their physical principles are reviewed, the clinical experiences demonstrating the feasibility of new techniques are then summarized and finally, the early clinical use and its impact on clinical practice is review.

https://tel.archives-ouvertes.fr/docs/00/45/61/68/ANNEX/Article1_Cancer-radiotherapie.pdf

Radiotherapy quality insurance by individualized in vivo dosimetry: State of the art

This paper presents the design of two configurations of electrodes ("gold versus Ag/AgCl" and "gold versus gold") and an electrochemiluminescence (ECL) microfluidic device fabricated in the inexpensive printed circuit board (PCB) technology. The PCB electrodes are electrochemically characterized to determine appropriate working potentials. The ECL microfluidic device with integrated PCB electrodes is tested using luminol as luminophore to quantify H2O2 concentrations. Synchronous detection technique is implemented for weak signal recovery. For both PCB electrode configurations, a 100 nM H2O2 concentration is detected and a linear range extending from 100 nM to 10 mM is observed with a photomultiplier tube. A lab-on-board compatible potentiostat and a compact CMOS photodetector module are also designed and validated. The proposed instrumental approach may represent a low-cost way to develop portable analytical systems.

PCB Technology-Based Electrochemiluminescence Microfluidic Device for Low-Cost Portable Analytical Systems

The authors present a novel technique for color detection by using a buried double pn junction (B.D.J.) and a buried triple pn junction (B.T.J.) structure. For the B.D.J. wavelength-dependent photocurrents I1 and I2 can be measured. The wavelength of monochromatic incident light can be identified from the ratio I2/I1. In the case of the B.T.J. with wavelength dependent photocurrents the three colorimetric components of the incident light can be extracted. These structures can be implemented in standard CMOS and BiCMOS technology respectively.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Guo-Neng Lu

Papers

Wide-linear-range subthreshold OTA for low-power, low-Voltage, and low-frequency applications

Photodetector based on buried junctions and a corresponding method of manufacture

Radiotherapy quality insurance by individualized in vivo dosimetry: State of the art

PCB Technology-Based Electrochemiluminescence Microfluidic Device for Low-Cost Portable Analytical Systems

Color-sensitive photodetectors in standard CMOS and BiCMOS technologies