Browsing by Author "Lin, LJ"

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A CMOS focal-plane rotation sensor with retinal processing circuit
(2003)
Huang, KH
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Lin, LJ
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Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a CMOS focal-plane rotation sensor with the retinal processing circuit is proposed and implemented. The proposed rotation sensor has a polar structure and is selective to the angular velocity and direction (clockwise and counterclockwise) of the rotating images. The selected angular velocity depends on the frequency of an external clock signal, which can be precisely adjusted. In the proposed rotation sensor, there are 104 pixels, which form five concentric circles. The area of a single pixel is 91x84 mum(2) with a fill factor of 20% whereas the chip area is 1812x1825 mum(2). It is found from the experimental results that the detectable angular velocity and illumination range of this rotation sensor are from 2x10(-2) pi/sec to 206 pi/sec as well as from 0.91 lux to 366 lux under a contrast of 80%, respectively.
A new light-activated CMOS retinal-pulse generation circuit without external power supply for artificial retinal prostheses
(2001)
Wu, CY
;
Lin, LJ
;
Huang, KH
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A new approach to implement the artificial retinal prosthesis using the silicon retina chip is proposed in this paper. In the proposed new approach, a new light-activated CMOS retinal pulse generation circuit is designed by using the gate-controlled lateral npn and pnp bipolar junction transistors (BJTs) to form the new BJT-based silicon retina structure. With the BJT served as a photovoltaic device, which generates power under incident light, the designed circuit does not require external power supply. Moreover, the proposed new circuit can function as photoreceptors, horizontal cells, and bipolar cells of the real vertebrate retina to generate retinal pulses under moving object or flash light image. Both static and dynamic functions of the proposed circuit have been verified by using HSPICE simulation. An experimental chip with 32x32 silicon retina cell array is designed by using 0.25mum one-poly-five-metal CMOS technology with deep n-wells. The chip will be implanted to eyes in animal tests.
A new pseudo-bipolar-junction-transistor (PBJT) and its application in the design of retinal smoothing network
(2002)
Wu, CY
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Huang, HC
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Lin, LJ
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Huang, KH
;
電機學院
A new MOSFET circuit structure called the pseudo-BJT (PBJT) is proposed and analyzed in this work. This new structure mimics the function of the BJT, and it has advantages of smaller area and better process compatibility over the real BJT. The function of PBJT is verified to be similar to the real BJT via HSPICE simulation. Moreover, applications of the retinal smoothing network and the edge-extracting circuit using the PBJT structure are also demonstrated. The PBJT plays the role of the real BJT in both applications, and they are verified to be functionally correct via HSPICE simulations.
A new structure of large-neighborhood cellular nonlinear network (LN-CNN)
(2003-01-01)
Cheng, CH
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Chen, SH
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Lin, LJ
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Huang, KH
;
Wu, CY
In this paper, a novel Large-Neighborhood Cellular Nonlinear Network (LN-CNN) structure is proposed and analyzed. The proposed LN-CNN structure can realize both A and B templates with more than two neighborhood layers without complex direct connections between neural cell and neighboring cells. In both A and B templates, the first layer is defined by 4 neighboring cells located at the 4 corners of a diamond shape whereas the second layer is defined by 8 cells. In realizing the 12 template coefficients of a template, only 8 connections are required as compared to 12 connections in the conventional CNN structure. Thus the required chip area for synaptic connection can be reduced. Using the proposed LN-CNN structure, the LN-CNN functions, such as noise removing, Muller-Layer arrowhead illusion, and connected component detection, have been successfully realized and verified in MATLAB simulations. The constraints on the realized templates and the template coefficients in the third or higher layers are analyzed and discussed. Based upon he above successful simulation results, the application of the proposed LN-CNN structure to the design of LN-CNN Universal Machine (LN-CNNUM) is quite feasible. The related research will be conducted in the future.
A new two-layer quantum-dot large-neighborhood cellular nonlinear network (QLN-CNN) using quantum-dot cellular automata
(2002)
Tsai, TC
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Sun, M
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Lin, LJ
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Huang, KH
;
Cheng, CH
A novel structure of QLN-CNN is proposed. The new structure of the QLN-CNN contains two layers of QCA array and introduces concepts of the A cloning templates, the B cloning templates, and the thresholds. The gene-decoding concept of CNNs is also used in this structure. Thus it operates more like real CNNs. In this paper, three CNN operations are proven to be achieved by this new structure through MATLAB simulations.
Analysis and design of a CMOS angular velocity- and direction-selective rotation sensor with a retinal processing circuit
(2004-12-01)
Huang, KH
;
Lin, LJ
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This paper implements and analyzes a CMOS angular velocity- and direction-selective rotation sensor with a retinal processing circuit. The proposed rotation sensor has a polar structure and is selective of the angular velocity and direction (clockwise and counterclockwise) of the rotation of images. The correlation-based algorithm is adopted and each pixel in the rotation sensor is correlated with the pixel that is 45degrees apart. The angular velocity selectivity is enhanced by placing more than one pixel between two correlated pixels. The angular velocity selectivity is related to both the number and the positions of the edges in an image. Detailed analysis characterizes angular velocity selectivity for different edges. An experimental chip consisting 104 pixels, which form five concentric circles, is fabricated. The single pixel has an area of 91 X 84 mum(2) and a fill factor of 20 %, whereas the area of the chip is 1812 x 1825 mum(2). The experimental results concerning the fabricated chip successfully verified the analyzed characteristics of angular velocity and direction selectivity. They showed that the detectable angular velocity and range of illumination of this rotation sensor are from 2.5 x 10(-3) pi /s to 40 pi/s and from 0.91 lux to 366 lux, respectively.
Band gap variation of size-controlled ZnO quantum dots synthesized by sol-gel method
(2005-06-30)
Lin, KF
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Cheng, HM
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Hsu, HC
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Lin, LJ
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Hsieh, WF
ZnO quantum dots were synthesized successfully via a simple sol-gel method. The average size of quantum dots can be tailored using well-controlled concentration of zinc precursor. Size-dependent blue shifts of photoluminescence and absorption spectra revealed the quantum confinement effect. The band gap enlargement is in agreement with the theoretical calculation based on the effective mass model. Furthermore, as the particle size decreases, we observed an increase in the size-dependent Stokes shift of the photoluminescence peak relative to the absorption onset. (c) 2005 Elsevier B.V. All rights reserved.
Efficient UV photoluminescence from monodispersed secondary ZnO colloidal spheres synthesized by sol-gel method
(2005-04-15)
Cheng, HM
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Hsu, HC
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Chen, SL
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Wu, WT
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Kao, CC
ZnO colloidal spheres were synthesized by sol-gel method with a narrow size distribution. We controlled the size of the spheres during the secondary reaction with various amounts of primary reaction supernatant. The optimized condition of ZnO powders with an average diameter of 185 nm was obtained for structure analysis and study of optical properties. Transmission electron microscopy and X-ray diffraction reveal that the spheres are polycrystalline in the pure wurtzite phase. Markedly enhanced near-band-edge ultraviolet pbotoluminescence and significantly reduced defect-related visible emission were also observed. We attribute this observation to the localized bound excitons with high density of defect states. In addition, broad yellow emission and green emission were observed when the powders were post-annealed at 500 degrees C in air ambience. The origins of the defect-induced visible emissions are attributed to oxygen interstitials and oxygen vacancies. (c) 2005 Elsevier B.V. All rights reserved.
Enhanced resonant Raman scattering and electron-phonon coupling from self-assembled secondary ZnO nanoparticles
(2005-10-06)
Cheng, HM
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Lin, KF
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Hsu, HC
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Lin, CJ
;
Lin, LJ
Self-assembled secondary ZnO nanoparticles, recognized with the agglomeration of crystalline subcrystals, are successfully synthesized by a simple sol-gel method. TEM images display that one artificial cluster behaves in a single-crystal-like wurtzite structure because subcrystals coagulate as the same crystal orientation. Moreover, from the resonant Raman scattering, the as-grown sample exhibits phonon red shift; meanwhile, the coupling strength between electron and longitudinal optical phonon, determined by the ratio of second to first-order Raman scattering cross sections, diminishes compared with the samples after postannealing at 350 and 500 degrees C. The size dependence of electron-phonon coupling is principally as a result of the Frohlich interaction.
In the blink of a silicon eye
(2001-05-01)
Cheng, CH
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Wu, CY
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Sheu, B
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Lin, LJ
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Huang, KH
Raman scattering and efficient UV photoluminescence from well-aligned ZnO nanowires epitaxially grown on GaN buffer layer
(2005-05-12)
Cheng, HM
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Hsu, HC
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Tseng, YK
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Lin, LJ
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Hsieh, WF
Optical phonon confinement and efficient UV emission of ZnO nanowires were investigated in use of resonant Raman scattering (RRS) and photoluminescence (PL). The high-quality ZnO nanowires with diameters of 80-100 nm and lengths of several micrometers were epitaxially grown through a simple low-pressure vapor-phase deposition method at temperature 550 &DEG; C on the precoated GaN(0001) buffer layer. The increasing intensity ratio of n-order longitudinal optical (LO) phonon (A(1) (nLO)/E-1 (nLO)) with increasing scattering order in RRS reveals the phonon quantum confinement as shrinking the diameter of ZnO nanowires. The exciton-related recombination near the band-edge transition dominate the UV emissions at room temperature as well as at low temperature that exhibits almost no other nonstoichiometric defects in the ZnO nanowires.
The design of a bionic sensory chip based on the CNN model derived from the mammalian retina
(2003)
Yang, WC
;
Lin, LJ
;
Wu, CY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this work, a bionic sensory chip based on the CNN model derived from the mammalian retina is proposed. A CMOS compatible sensory chip is designed based on the CNN model to mimic functions of photoreceptor and horizontal cell of the mammalian retina. The sensory chip contains a focal plane array of 32x32 similar pixels that perform functions of photoreceptor and horizontal cell. Spatial and temporal characteristics of a one-dimensional array are verified via HSPICE simulations in this paper, while a two-dimensional array of 32x32 cells is to be fabricated to investigate real-time images obtained by this bionic sensory chip.
The substrate effect on the in-plane orientation of vertically well-aligned ZnO nanorods grown on ZnO buffer layers
(2005-12-01)
Cheng, HM
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Hsu, HC
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Yang, S
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Wu, CY
;
Lee, YC
Vertically well-aligned ZnO nanorods were synthesized without employing any metal catalysts on various substrates including glass, Si(111), 6H-SiC(0001) and sapphire (0001), which were pre-coated with c-oriented ZnO buffer layers, by simple physical vapour deposition. The alignments of the ZnO nanorods on the different substrates depend on the crystallographic alignments of the pre-coated ZnO buffer layers. The ZnO nanorods grown on glass and Si(111) are vertically aligned but randomly oriented in the in-plane direction. In contrast, the vertically aligned ZnO nanorods on 6H-SiC(0001) and sapphire (0001) show an in-plane alignment with azimuthally sixfold symmetry, which indicates the epitaxial relationship between ZnO and the substrate. Similarly, photoluminescence measurements show the distinct appearance of ZnO nanorods on different substrates. Besides the UV band, which was attributed to the recombination of free excitons near the band edge, defect-related visible emissions were also observed for the samples grown on both glass and Si(111) substrates. However, the ZnO nanorods exhibit only strong band edge emission peaks with no noticeable deep level emissions when grown on the 6H-SiC(0001) and sapphire (0001) substrates, which confirms the good crystalline and optical quality of the epitaxial ZnO nanorods.