Improved Concept for Nipiin and PIIIN Color Sensitive Two-Terminal Devices with High Linearity

1997 ◽  
Vol 467 ◽  
Author(s):  
D. Knipp ◽  
H. Stiebig ◽  
J. Fölsch ◽  
R. Carius ◽  
H. Wagner
Keyword(s):  
Light Intensity ◽  
Dynamic Range ◽  
Layer Structure ◽  
Spectral Response ◽  
Incident Light ◽  
High Dynamic Range ◽  
Optical Signal ◽  
Optimized Design ◽  
Defect States ◽  
Response Curves

ABSTRACTThe detection of the fundamental components of the visible light (blue, green, red) is achieved with two terminal photo diodes based on amorphous silicon. By changing the bias voltage the preferential carrier collection region is shifted which leads to a color sensitivity. In order to obtain a high dynamic range, independent voltage controlled spectral response curves as well as a linear response of the photocurrent on the incident light intensity the μτ-product and the bandgap in the device have to be specially designed to deconvolute the optical signal and generate an RGB-signal. Since the light intensity can strongly influence the spectral sensitivity by recharging of defect states, an optimized design of the multi-layer structure is necessary. Therefore, an improved concept for the design of nipiin- and piiin-detectors is presented which results in a good suppression of these non-linearities. Our concept is based on a decreasing bandgap profile from the front to the back contact and an increasing μτ-product of the individual i-layers in direction of the p-layer.

scholarly journals PHOTOMETRIC CHARACTERIZATION OF A COMMERCIAL DSLR CAMERA FOR THE IMPLEMENTATION OF AN IMAGING LUMINANCE METER

Anales AFA ◽  
2021 ◽  
Vol 31 (4) ◽  
pp. 143-149
Author(s):  
O. U. Preciado ◽  
◽  
A. Décima ◽  
J.B. Barraza ◽  
◽  
...  
Keyword(s):  
Dynamic Range ◽  
Spectral Response ◽  
High Dynamic Range ◽  
Absolute Calibration ◽  
Successful Implementation ◽  
Pilot Test ◽  
Response Curves ◽  
Cmos Sensor ◽  
High Dynamic

In this paper we describe the procedure followed in the photometric characterization of a DSLR camera in order to implement an imaging luminance meter. The first step consisted in the experimental setup of a system to obtain the spectral response curves of the CMOS sensor for its three channels: red (R), green (G) and blue (B). Then, based on the linear combination of the RGB channel curves, we calculated an approximation of the CIE luminous efficiency function, V(λ), for the camera. We then characterized the camera lens which involved measuring its spectral transmittance and evaluating the uniformity of the lens-sensor assembly to compensate for loss of sensitivity at the image periphery (vignetting). Finally, we performed an absolute calibration in luminance and carried out a pilot test to create high dynamic range (HDR) images and luminance maps of a scene. The favourable results of the pilot test augur a successful implementation of the image luminance meter, however, it is necessary to finish with the development of a software for the image processing and to do more tests in order to be able to validate its use in different situations or to establish the restrictions of its use.

Subwavelength Periodic Structures Design and its Role in Photon Control of Thin Film Solar Cells

NANO ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. 2050139
Author(s):  
Zhiye Wang ◽  
Xiangqian Shen ◽  
Shuying Wang ◽  
Hua Zhou ◽  
Peihua Wangyang ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Periodic Structures ◽  
Spectral Response ◽  
Incident Light ◽  
Optical Loss ◽  
Thin Film Solar Cells ◽  
Photoelectric Conversion Efficiency ◽  
Optimized Design ◽  
Photoelectric Conversion

A subtle modification of the device surface is able to reduce optical loss and to further achieve high photoelectric conversion efficiency for thin film solar cells. This work shows the manipulation properties of subwavelength periodic structures on incident light at air/glass surface. In order to explore the mechanisms of optical loss, the spectral response and energy distribution of light are investigated by using rigorous coupled wave analysis and finite difference time domain methods. Calculation results show that the diffraction scattering and gradient refraction index play a significant role for better photon harvesting. With an optimized design of [Formula: see text][Formula: see text]nm, [Formula: see text], and hemispherical shape structure, obvious improvement in transmittance, external quantum efficiency and photo-generated current is achieved. The photoelectric conversion efficiencies of amorphous silicon thin film cells with an absorbing layer thickness of 400[Formula: see text]nm is 8.04%, improved by 5.9% compared with the flat cell of equivalent size.

PHOTOCONDUCTIVITY AND ABSORPTION AND FLUORESCENCE SPECTRA OF 9,10-DICHLOROANTHRACENE

1958 ◽  
Vol 36 (3) ◽  
pp. 507-512 ◽  
Author(s):  
E. Bock ◽  
J. Ferguson ◽  
W. G. Schneider
Keyword(s):  
Absorption Spectrum ◽  
Light Intensity ◽  
Fluorescence Spectra ◽  
Spectral Response ◽  
Incident Light ◽  
Chloroform Solution ◽  
Absorption And Fluorescence Spectra ◽  
Crystal Face ◽  
Response Voltage ◽  
Temperature Dependences

The spectral response, voltage, light intensity, and temperature dependences of the photocurrent generated in crystals of 9,10-dichloroanthracene have been studied as well as the absorption and fluorescence spectra. The magnitude of the measured photocurrent was 102–103 times larger than that observed in anthracene under similar conditions. The spectral response of the photocurrent in the surface cell arrangement was found to depend on the direction of the incident light relative to the electrodes. Above a certain value of the applied voltage the photocurrent was found to be ohmic. The photocurrent increased as the 0.7 or 0.8 power of the light intensity depending on whether the light was incident on the same side or opposite sides of the crystal face containing the electrodes. When the crystal was cooled the photocurrent passed through a maximum between 20° and 0 °C.The absorption edge of crystalline 9,10-dichloroanthracene as well as the absorption spectrum in chloroform solution were determined. When the crystals were cooled the fluorescence spectrum was observed to shift to longer wavelengths and the intensity increased between two and three times.

A new high dynamic range ROIC with smart light intensity control unit

2017 ◽  
Vol 82 ◽  
pp. 161-169 ◽  
Author(s):  
Melik Yazici ◽  
Omer Ceylan ◽  
Atia Shafique ◽  
Shahbaz Abbasi ◽  
Arman Galioglu ◽  
...  
Keyword(s):  
Light Intensity ◽  
Dynamic Range ◽  
Control Unit ◽  
High Dynamic Range ◽  
Intensity Control ◽  
High Dynamic

Amorphous Silicon Three Color Detector

1995 ◽  
Vol 377 ◽  
Author(s):  
H. Stiebig ◽  
J. Giehl ◽  
D. Knipp ◽  
P. Rieve ◽  
M. Böhm
Keyword(s):  
Amorphous Silicon ◽  
Analytical Model ◽  
Integrated Circuit ◽  
Dynamic Range ◽  
Circuit Simulation ◽  
Spectral Response ◽  
Simulation Program ◽  
Response Curves ◽  
Pool Model ◽  
Color Sensors

ABSTRACTBand gap and defect engineered amorphous silicon based nipin photo diodes with bias controlled spectral response have been fabricated successfully. The devices exhibit good linearity over a wide illumination range and linearly independent spectral response curves which are required to generate a standard RGB-signal. In the bias range from -1.5 V to 1.5 V a dynamic range exceeding 90 dB for two color sensors and 80 dB for three color sensors has been observed. The general operation principle of the multispectral photo diode is discussed using a numerical simulation program. The model describes the defect state distribution of dangling bonds according to the defect-pool model and uses coherent wave propagation in the device to calculate the profile of photo generated carriers. Additionally, an analytical model has been developed to be included into standard circuit simulation programs like SPICE (Simulation Program with Integrated Circuit Emphasis). The analytical model uses linear field approximations in both i-layers of the device.

Ubiquitous luminance sensing using the Raspberry Pi and Camera Module system

2016 ◽  
Vol 49 (7) ◽  
pp. 904-921 ◽  
Author(s):  
AR Mead ◽  
KM Mosalam
Keyword(s):  
Dynamic Range ◽  
Imaging Techniques ◽  
Spectral Response ◽  
Single Point ◽  
High Dynamic Range ◽  
Linear Mapping ◽  
Raspberry Pi ◽  
Camera System ◽  
Camera Module ◽  
Discomfort Glare

In this paper, the authors have calibrated a Raspberry Pi and Camera Module (RPiCM) for use as an absolute luminance sensor. The spectral response of the RPiCM chip as well as linear mapping to the standard CIE-XYZ colour space have been measured, calculated and presented. The luminance values are anchored to absolute luminance measurements. Further, by using high dynamic range imaging techniques making use of different shutter speeds in a sequence of images, the measurement of luminance values from approximately 10 to 50,000 cd/m2 is possible. Lens correction for vignetting is also addressed, while pixel point spreading is ignored. This measurement goes beyond a single point measurement, economically and accurately allowing each of the arrays within the RPiCM chip to act as an individual luminance meter over the entire field of view of the camera system. Applications and limitations of the embedded camera system are discussed. An Energy Plus model is constructed as a motivational application of a simple one room, one window space and simulated for a year using weather files from around the world. These simulations highlight the need for spatial luminance-based sensing within the built environment to counteract the experience of discomfort glare by building occupants.

Dynamic Range Extend on Finger Vein Image Based on Infrared Multi-Light-Intensity Vascular Imaging

2013 ◽  
Vol 427-429 ◽  
pp. 1832-1835 ◽  
Author(s):  
Liu Kui Chen ◽  
Zuo Jin Li ◽  
Ying Wu ◽  
Yi Xiang
Keyword(s):  
Light Intensity ◽  
Image Fusion ◽  
Dynamic Range ◽  
Image Acquisition ◽  
High Dynamic Range ◽  
Vascular Imaging ◽  
Current Image ◽  
Finger Vein ◽  
High Dynamic ◽  
Acquisition Method

This paper proposes an extending dynamic range method for infrared finger vein image acquisition by multi-light-intensity imaging. The captured images contain high dynamic range by different light intensity irradiating. The fast switch of light-intensity is synchronous with the camera imaging and the current image illumination analysis, these ensure the light intensity is automatic regulated and the captured images are in pixel-level registration. The experiment shows the proposed acquisition method is effective and the captured multi-light-intensity finger vein images are convenient for image fusion and subsequent processing.

scholarly journals Comparison of Vegetation Indices for Leaf Area Index Estimation in Vertical Shoot Positioned Vine Canopies with and without Grenbiule Hail-Protection Netting

2019 ◽  
Vol 11 (9) ◽  
pp. 1073 ◽  
Author(s):  
Pedro C. Towers ◽  
Albert Strever ◽  
Carlos Poblete-Echeverría
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Linear Models ◽  
Dynamic Range ◽  
Spectral Response ◽  
Incident Light ◽  
Vegetation Indices ◽  
Area Index

Leaf area per unit surface (LAI—leaf area index) is a valuable parameter to assess vine vigour in several applications, including direct mapping of vegetative–reproductive balance (VRB). Normalized difference vegetation index (NDVI) has been successfully used to assess the spatial variability of estimated LAI. However, sometimes NDVI is unsuitable due to its lack of sensitivity at high LAI values. Moreover, the presence of hail protection with Grenbiule netting also affects incident light and reflection, and consequently spectral response. This study analyses the effect of protective netting in the LAI–NDVI relationship and, using NDVI as a reference index, compares several indices in terms of accuracy and sensitivity using linear and logarithmic models. Among the indices compared, results show NDVI to be the most accurate, and ratio vegetation index (RVI) to be the most sensitive. The wide dynamic range vegetation index (WDRVI) presented a good balance between accuracy and sensitivity. Soil-adjusted vegetation index 2 (SAVI2) appears to be the best estimator of LAI with linear models. Logarithmic models provided higher determination coefficients, but this has little influence over the normal range of LAI values. A similar NDVI–LAI relationship holds for protected and unprotected canopies in initial vegetation stages, but different functions are preferable once the canopy is fully developed, in particular, if tipping is performed.

Systems. An Analog High-Performance Transfer-Stabilized Fiber-Optic Transmission System for Baseband Video Signals

1984 ◽  
Vol 5 (3) ◽  
Author(s):  
L. P. de Jong ◽  
E. H. Nordholt
Keyword(s):  
High Performance ◽  
Dynamic Range ◽  
Automatic Gain Control ◽  
Low Cost ◽  
Gain Control ◽  
High Dynamic Range ◽  
Optical Signal ◽  
Transmission System ◽  
Low Noise ◽  
Noise Current

SummaryA low-cost video baseband transmission system using analog light-intensity modulation with an 850 nm LED compensated for nonlinearity is presented. A very low- noise current amplifier at the input of the receiver and a high-dynamic range automatic gain control provide a transmission system that can accomodate more than a 20 dB difference in optical losses without any adjustment. At the receiver input, a 100 nW (- 40 dBm) optical signal is required for surveillance transmission quality. The transmitter delivers an optical signal power of - 18 dBm to a 50 pm graded-index fiber. The differential gain and phase of the system lie below 2% and 1°, respectively.

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