A magnetic head includes a read sensor having a primary stack, a secondary stack and an exchange layer. The primary stack includes one or more primary pinned layers having a top surface, a barrier layer, a free layer, and a seed layer. The secondary stack includes one or more layers of antiferromagnetic (AFM) material, and a secondary pinned layer, which is pinned by said AFM material. The secondary pinned layer has a top surface which is substantially level with the top surface of the primary pinned layer. An exchange layer contacts the top surface of the secondary pinned layer and is pinned thereby, and also contacts the top surface of the primary pinned layer and acts to pin the primary pinned layers. The secondary stack is removed from the ABS, but is in proximity to the primary stack.

1. Field of the Invention
The present invention relates generally to read heads for magnetic data storage mediums, and more particularly to a read head sensor using antiferromagnetic material to fix pinned layers in the sensor.
2. Description of the Prior Art
A computer disk drive stores and retrieves data by positioning a magnetic read/write head over a rotating magnetic data storage disk. The head, or heads, which are typically arranged in stacks, read from or write data to concentric data tracks defined on surface of the disks which are also typically arranged in stacks. The heads are included in structures called "sliders" into which the read/write sensors are imbedded during fabrication. The heads fly above the surface of the disks on a thin cushion of air, and the surface of the heads which face the disks is called an Air Bearing Surface (ABS).
The major goal in recent years is to increase the amount of data that can be stored on each hard disk. If data tracks can be made narrower, more tracks will fit on a disk surface, and more data can be stored on a given disk. The width of the tracks depends on the width of the read/write head used, and in recent years, track widths have decreased as the size of read/write heads have become progressively smaller. This decrease in track width has allowed for dramatic increases in the recording density and data storage of disks.
Recent read heads typically use a tunnel junction sensor for reading the magnetic field signals from the rotating magnetic data storage disk. The sensor typically includes a nonmagnetic tunneling barrier layer sandwiched between a ferromagnetic pinned layer and a ferromagnetic free layer. The pinned layer in turn is typically fabricated on or beneath an antiferromagnetic (AFM) pinning layer which fixes the magnetic moment of the pinned layer at an angle of 90 degrees to the air bearing surface (ABS). The tunnel junction sensor is itself typically sandwiched between ferromagnetic first and second shield layers. These first and second shield layers also serve as first and second leads, and are connected to the tunnel junction sensor for conducting a tunneling current through it. The tunneling current is preferably configured to Current Perpendicular to the Planes (CPP) of the film layers of the sensor, as opposed to a sensor where a sense Current In the Planes (CIP) or parallel to film layers of the spin valve sensor. The CPP configuration is attracting more attention lately, as it can be made to be more sensitive than the CIP configuration, and thus is more useful in higher densities of tracks and data.
AFM material used to fix the orientation of the pinned layer must be in close proximity to the pinned layer and is typically fabricated on top or beneath the pinned layer. The AFM material thus contributes to the overall height of the stack of layers, and thus to the overall height dimension of the read sensor. This contribution can be substantial, as it is not uncommon for the AFM material to be as thick as the other layers combined. As discussed above, the quest in disk drive head manufacture is for reduced size. Thus, a configuration which reduces the overall thickness of the sensor by repositioning the AFM material would have significant advantages.
Also as discussed above, CPP configurations are becoming more favored for their increased sensitivity. This configuration requires that electric current be conducted through every layer of the stack. The AFM material which is included in the typical stack must therefore necessarily be conductive. However, resistance in the materials generally causes them to heat as they conduct. This heat can cause variation in the magnetic properties of AFM materials, and thus also in the pinned layer. If the AFM material were removed from the conduction path, and made of insulating materials, overall stability would be improved.
Thus there is a need for an improved configuration of read head sensor which has reduced overall dimensions, and improved stability of its magnetic properties.

Top CPP GMR/TV with back end of stripe pinned by insulating AFM

Hitachi Global Storage Technologies Netherlands, B.V.


An information processing apparatus and method enables a pattern discriminator to learn. The apparatus establishes a branch structure appropriate for learning a discriminator having the branch structure without increasing processing time. The apparatus includes a preliminary learning unit to learn a preliminary discriminator for a respective one of a plurality of combinations of variations in variation categories in a discrimination target pattern. A branch structure determination unit is provided to perform discrimination processing using the preliminary discriminator and to determine a branch structure of a main discriminator based on a result of the discrimination processing. A main learning unit is included to learn the main discriminator based on the branch structure.

1. Field of the Invention
The present invention relates to an information processing apparatus enabling a pattern discriminator to learn and a method thereof.
2. Description of the Related Art
In recent years, in the field of pattern recognition, a method has drawn attention in which weak discriminators are cascade-connected to configure a pattern discriminator and to perform speedy detection processing on an object, such as a human face in an image. For example, in a method proposed by P. Viola and M. Jones, in "Rapid Object Detection using a Boosted Cascade of Simple Features", Proc. IEEE Conf. on Computer Vision and Pattern Recognition, Vol. 1, pp. 511-518, December 2001, firstly, a predetermined number of weak discriminators which extract a rectangular feature are cascade-connected to configure a strong discriminator referred to as a stage.
This weak discriminator is generated by a boosting learning algorithm (refer to Japanese Patent Application Laid-Open No. 8-329031). Further, the above-described method proposes a pattern discriminator having a structure in which a plurality of stages are cascade-connected. Since processing proceeds while performing termination determination processing (termination processing on a detection target position in the image) in each stage, which is the strong discriminator, a further operation is terminated to be performed at an early point on an input determined to be the non-detection target. Thus, processing can be performed at high speed as a whole. A method for discriminating a pattern will be described in detail below.
As illustrated in FIG. 1, the pattern discriminator described in the above-described literature enables a rectangular region 801 having a certain specified size (hereafter, referred to as a "processing window") to move within a face detection target image 800, which is a processing target, and to determine whether the processing window 801 includes a human face at each destination.
FIG. 2 illustrates a flow of face detection processing which is performed in the processing window 801 at each destination, as discussed in the above-described literature. The face detection processing in a certain processing window is performed in a plurality of stages. In each stage, weak discriminators having different combinations are allocated and cascade-connected to generate a strong discriminator.
Each weak discriminator detects a so-called Haar-like feature and includes a combination of rectangular filters. As illustrated in FIG. 2, each stage has a respective different number of weak discriminators. Each stage unit is configured by the cascade connection and performs the determination processing according to the order of connection. For example, in FIG. 2, a second stage follows a first stage for determination, and then a third stage follows the second stage therefor.
Each stage determines, according to an order assigned thereto, whether the processing window includes a human face by using the weak discriminator of the pattern assigned to each stage. In a certain stage, when it is determined that the processing window does not include a human face at a position, in following stages, the processing window does not perform the determination processing at that position (cascade processing is terminated). When the last determination processing determines that the processing window includes a human face, it is determined that the processing window includes a human face at this destination.
FIG. 3 is a flowchart illustrating an example of face detection processing. A flow of the face detection processing will be described more specifically with reference to FIG. 3.
In step S1001, in the face detection processing, the processing window 801, which is a processing target, is disposed on a face detection target image 800. Basically, as illustrated in FIG. 1, the processing window moves as scanning from an edge of the face detection target image 800 at a certain space in vertical and horizontal directions and selects a position to be processed. For example, the processing window is selected by raster scanning the face detection target image 800.
Subsequently, it is determined whether the processing window at the selected position includes a human face. The determination processing is performed using a plurality of stages as illustrated in FIG. 2. In step S1002, the stage for performing the determination processing is selected from the first stage in order.
In step S1003, the selected stage performs the determination processing. When it is determined in the selected stage that a summed score does not exceed a threshold value predetermined for each stage (NO in step S1004), then in step S1008, it is determined that the processing window does not include a human face, and the processing proceeds to step S1007 and following steps thereof. The processing in step S1007 and the following steps will be described below.
When the summed score exceeds the threshold value predetermined for each stage (YES in step S1004), it is determined whether the determination processing in step S1003 is performed in the last stage. When it is determined the determination processing in step S1003 is not performed in the last stage (NO in step S1005), the processing returns to S1002 and a following stage is selected to perform the determination processing by a newly selected stage. When it is determined that the determination processing in step S1003 is performed in the last stage (YES in step S1005), then in step S1006, it is finally determined that a current processing window includes a human face. At this point, this processing window is determined to include a human face.
Further, it is determined whether the processing window is the last processing window in the face detection target image. When the processing window is not determined to be the last processing window (NO in step S1007), the processing returns to step S1001, and the following processing window is selected to perform the processing of step S1002 and the following steps thereof. When the processing window is determined to be the last processing window, the face detection processing of the input image of the face detection target ends.
The processing of the determination for each stage will be described below.
The weak discriminators of one or more patterns are assigned for each stage. Boosting learning algorithm such as AdaBoost assigns the weak discriminator in leaning processing. Each stage determines whether the processing window includes a human face based on the weak discriminator of the pattern assigned to each stage.
In each stage, feature quantities are calculated in each of a plurality of rectangular regions in the processing window based on the weak discriminator having each pattern assigned to each stage. The feature quantity acquired herein is a total value or an average value of pixel values in each rectangular region, that is, a calculated value using a total value of the pixel values in the rectangular region. The total value in the rectangular region can be calculated at high speed by using summed area table information (referred to as "SAT" or "Integral Image") of the input image.
FIGS. 4A and 4B illustrate an example of SAT. FIG. 4A illustrates an original input image. An upper left point is defined as an origin (0, 0). When a pixel value of a coordinate position (x, y) in the input image (FIG. 4A) is defined as the pixel value I (x, y), an element C (x, y) of a position in the coordinate position (x, y) of SAT is defined by equation (1) as below.
                              C                                (                          x              ,              y                        )                          =                              ∑                                                            x                  ′                                ≤                x                                                              y                  ′                                ≤                y                                                                    I                                      (                                                x                  ′                                ,                                  y                  ′                                            )                                                          (        1        )
More specifically, as illustrated in FIG. 4B, a total value of the pixels in the rectangle having the pixels of the origin (0, 0) and the position (x, y) as the opposing corners in the input image (FIG. 4A) is the value C (x, y) of the position (x, y) in SAT (FIG. 4B). A sum of an arbitrary pixel value I (x, y) in the rectangular region in the input image (FIG. 4A) can be acquired only by referring to four points of SAT (FIG. 4B).
For example, as illustrated in FIG. 5, when a total sum C (x0, y0 y1) of the pixel values in the rectangular region having (x0, y0) and (x1, y1) as the opposing corners is acquired by using equation (2) as below.C(x0,y0;x1,y1)=C(x0−1,y0−1)−C(x0−1,y1)−C(x1,y0−1)+C(x1,y1)  (2)
A difference value as a relative value of the calculated feature quantity (for example, ratio and difference value, herein, the difference value of the feature quantities is assumed to be calculated) is calculated, and it is determined whether the processing window includes a human face based on the difference value. More specifically, it is determined whether the calculated difference value is larger or smaller than the threshold value set for the weak discriminator of the pattern which is used for determination. According to the determination results, it is determined whether the processing window includes a human face.
However, the determination at this point is obtained based on the weak discriminator of each pattern but not based on the stage. As described above, in each stage, the determination processing is performed separately based on each of all weak discriminators having the assigned pattern to obtain the determination results.
The summed score in the stage is calculated. A reliability weight (score) is separately assigned to each weak discriminator of the pattern. The reliability weight refers to "certainty of determination" for a sole weak discriminator, which is a fixed value indicating the sole reliability.
When it is determined that the processing window includes a human face, the score corresponding to the weak discriminator of the pattern used for the determination is referred to and added to the summed score of the stage. As described above, the total sum of added individual scores is calculated as the summed score in the stage.
More specifically, this summed score is a value indicating the certainty of the determination (reliability for the entire stage). When the reliability for the entire stage exceeds a predetermined threshold (threshold of the entire stage reliability), it is determined that the processing window possibly includes a human face in this stage, and the processing continues to proceed to the following stage. When the reliability for the entire stage in this stage does not exceed the threshold value, it is determined that the processing window does not include a human face, and the processing terminates the following cascade processing.
The above-described literature realizes the speedy pattern identification, which is typical detection of the face. A detection unit illustrated in FIGS. 2 and 3 can be used as a pattern discriminator for objects other than faces if only appropriate learning is previously performed.
Further, Japanese Patent Application Laid-Open Nos. 2004-185611 and 2005-44330 also discuss a technique relating to a method and an apparatus for discriminating the pattern based on an idea of the above-described literatures. The pattern discriminator having the structure in which the weak discriminators are cascade-connected in one line as described above can provide a sufficient and speedy identification ability when a pattern (detection target pattern) similar to a face is separated from other patterns (non-detection target patterns) in the image.
However, for example, when the detection target pattern is a face image, even if the face keeps facing front, if the face tilts some ten degrees right or left (in-plane rotation), the face cannot be "very similar" to an original upright front face. Additionally, if the face is rotated in an axial direction in which the front face changes to a side face (depth rotation or depth rotation in the horizontal direction), the face becomes a two-dimensional image pattern, which is different from the original face.
It is impossible to identify the largely changing pattern by cascade-connecting in one line. The cascade-connecting structure of the weak discriminators is used for gradually eliminating a non-detection target pattern which is not similar to the detection target pattern to be identified. Thus, the patterns to be identified need to be very similar to each other.
When only the in-plane rotation is performed, if the input image is input while being rotated sequentially, the discriminator detecting the front face that is nearly upright can identify the face at any angle of 360 degrees. However, this method increases a processing time according to an increasing number of rotations. When the depth rotation is added, the discriminator cannot perform the processing.
Z. Zhang, L. Zhu, S. Z. Li, and H. Zhang "Real-Time Multi-View Face Detection", Proceedings of the Fifth IEEE International Conference on Automatic Face and Gesture Recognition (FGR' 02), discusses a discriminator having a pyramid structure in a hierarchy state based on a Coarse to Fine strategy.
In this discriminator, in a first layer, a learning image pattern including all variations of a face direction to be detected is input to learn the stage. In a second layer, the variation of the face direction is divided into each predetermined range to learn a plurality of stages by the learning image patterns including the only divided variations.
In the following layer, the range is further divided into smaller ranges to learn the stages. As described above, as the layer is advanced, a strong discriminator (stage) having gradually decreased robustness is being constituted like a pyramid. This discriminator can only divide the variation of the face direction rotated by the depth rotation in the horizontal direction. The discriminator divides a ±90 degrees' range of the entire range by the depth rotation into three in the second layer and into nine in the third layer, but does not process the in-plane rotation.
When the detection processing is performed, if an input sub window passes the stage in the first layer, the stage in the second layer is sequentially performed. The sub window passes any one of the stages, and then proceeds to a following stage. As described above, the discriminator can detect the face patterns of all variations starting with a rough detection and performing gradually more accurate detections.
Japanese Patent Application Laid-Open No. 2005-284487 discusses a method for constituting the discriminator having a tree structure in which the detection units having the high robustness are gradually divided and a sub-window image is input into the detection unit having the lower robustness. This discriminator learns to process a part of the divided range of the variation which a parent node processes. The variation of the face direction in an exemplary embodiment of this method includes the depth rotation in the vertical direction in which the face moves up and down from a front position as well as the depth rotation in the horizontal direction.
After the detection processing of a first node including all depth rotations in the vertical and horizontal directions is performed, the variation of the face directions is divided into three, which are the front face and the two faces rotated right and left by the depth rotation. The faces are further divided in the vertical direction by the depth rotation in the following layer. Only the variation of the front face by the rotation in the vertical direction is divided in the following layer. The branch structure as described above is predetermined and a great number of pieces of sample data corresponding to each variation are input to learn the branches.
Unlike the literature by Zhang et al., the method discussed in Japanese Patent Application Laid-Open No. 2005-284487 does not need to perform an operation of the variation in a lower layer included in the variation in the terminated upper layer, and thus the speedy performance can be realized. The weak discriminator discussed in Japanese Patent Application Laid-Open No. 2005-284487 uses a pixel difference not the rectangular difference. However, Japanese Patent Application Laid-Open No. 2005-284487 and the literature by Zhang et al. share an idea that the weak discriminators constitute the strong discriminator by the cascade connection.
C. Huang, H. Ai, Y. Li, and S. Lao "Vector Boosting for Rotation Invariant Multi-View Face Detection", Tenth IEEE International Conference on Computer Vision (ICCV2005), Volume 1, 17-21 Oct. 2005, pp. 446-453, discusses another leaning method of the discriminator having a similar tree structure to that of Japanese Patent Application Laid-Open No. 2005-284487.
The variations that the discriminator described in the above literature can process are the in-plane rotation and the depth rotation in the horizontal direction. From the node including all variations in the first layer, the depth rotation in the horizontal direction is divided into five in two stages, and then each of the rotational variations is further divided into three in the fourth layer. According to this structure, the learning proceeds similarly to that in the above-described literature.
Unlike the above-described literature, an output of the discriminator of each node to be learnt before reaching the final branch is not a scholar value but a vector value of the number of elements corresponding to the number of branches of the layer right down the node. More specifically, each node detector before the branch is generated has a function for selecting the branch for the following layer as well as terminating a non-face image. When detection is performed, only the branch corresponding to an element having a vector value of each node of nearly one is started up. Thus, an unnecessary operation does not have to be performed, thereby ensuring the speedy performance.
The literatures by Zhang et al., Huang et al., and Japanese Patent Application Laid-Open No. 2005-284487 determine the method for dividing the range of the variation by the Coarse to Fine strategy or the tree structure. For example, in the literature by Zhang et al., only the variation by the depth rotation in the horizontal direction can be divided, but not the in-plane rotation.
Japanese Patent Application Laid-Open No. 2005-284487 discusses the variation by the depth rotation in both of the horizontal and vertical directions to determine the structure such that the variation in the horizontal direction is divided in the upper layers, and then the variation in the vertical direction is divided in the lower layers. The literature by Hueng et al. divides the variation by the in-plane rotation after the variation by the depth rotation in the horizontal direction is divided.
Since these branch structures are experimentally (or, intuitively) determined by a human who performs machinery learning processing, the branch structure is not necessarily constituted best to identify the pattern including the variation to be identified. For example, in the literature by Huang, et al. described above, if the variation by the depth rotation is divided after the variation by the in-plane rotation is divided, the identification performance may be improved or a processing speed may be improved, since a ratio for terminating the branch which does not include an input pattern in an early point.
After various branch structures are checked to select the most appropriate branch structure, the structure having the best detection performance may be adopted. However, the mechanical learning processing is generally very time consuming, it is not realistic to perform all-play-all processing.

Information processing apparatus enabling discriminator to learn and method thereof


The Global Dynamic Critical Path is used to optimize the design of a system-on-a-chip (SoC), where hardware modules are in different clock domains. Control signal transitions of the hardware modules are analyzed to identify the Global Dynamic Critical Path. Rules are provided for handling specific situations such as when concurrent input control signals are received by a hardware module. A configuration of the hardware modules is modified in successive iterations to converge at an optimum design, based on a cost function. The cost function can account for processing time as well as other metrics, such as power consumed. For example, during the iterations, hardware modules which are in the Global Dynamic Critical Path can have their clock speed increased and/or additional resources can be added, while hardware modules which are not in the Global Dynamic Critical Path can have their clock speed decreased and/or unnecessary resources can be removed.

A system-on-a-chip (SoC) integrates all components of a computer or other electronic system into a single integrated circuit or chip. It may contain digital, analog, mixed-signal, and often radio-frequency functions. A typical SoC can include a microcontroller, microprocessor or digital signal processor (DSP) cores. Some SoCs, referred to as multiprocessor System-on-Chip (MPSoC), include more than one processor core. Other components include memory blocks such as ROM, RAM, EEPROM and Flash, timing sources including oscillators and phase-locked loops, peripherals including counter-timers, real-time timers and power-on reset generators, external interfaces including industry standards such as USB, FireWire, Ethernet, USART, SPI, analog interfaces such as analog-to-digital converters (ADCs) and digital-to-analog converters (DACs), and voltage regulators and power management circuits.
These components are connected by either a proprietary or industry-standard bus such as the Advanced Microcontroller Bus Architecture (AMBA) bus, or by DMA controllers which route data directly between external interfaces and memory, bypassing the processor core and thereby increasing the data throughput of the SoC. Example applications for SoC include music players and video game consoles, among many other possible applications.
Moreover, silicon process technology scaling has enabled very high degrees of integration resulting in complex SoC designs, spanning designs from complex chip multi-processors to highly integrated embedded systems. The SoC building blocks—referred to as Intellectual Property (IP) blocks—used by a manufacturer may come from a variety of internal and external sources. Regardless of the SoC IP block source, the internal operation of modules and associated corner cases may not be well understood or transparent to the SoC designers. Furthermore, with the high degree of integration among IP blocks, and with the increasing amount of concurrent execution, understanding the interactions between various modules or blocks has become very difficult. SoC designers are often forced to make educated guesses about the way the different modules impact each other's performance. This is further complicated by third party vendors of IP blocks that do not provide source code access for their modules. All of these factors make performance analysis of SoCs extremely difficult.
Improved techniques are need for optimizing SoC designs.

Optimizing systems-on-a-chip using the dynamic critical path


An exemplary embodiment of the feed forward amplifier replaces traditional distributed directional couplers, splitters, and delay lines. Moreover, an exemplary feed forward amplifier architecture combines active implementations of RF couplers, power splitters, and/or time delay elements in a novel fashion allowing for ultra-compact size and broadband performance. In an exemplary embodiment, a feed forward amplifier has a main amplifier path and an error amplifier path. The feed forward amplifier comprises a main amplifier in the main amplifier path, and at least one active vector generator in the error amplifier path. The at least one active vector generator is configured to adjust the phase and amplitude of an error amplifier path signal and an error amplifier is configured to receive the adjusted error amplifier path signal. Furthermore, the adjusted error amplifier path signal and an amplified signal are combined to form the output signal of the feed forward amplifier.

In general, radio frequency (RF) amplifiers do not provide pure linear amplification and produce undesired spurious or intermodulation products at the amplifier output. Various techniques are implemented to improve amplifier linearity, including pre-distortion, post-distortion, and different feedback configurations. Another technique is the feed forward amplifier. Generally, a feed forward amplifier comprises directional couplers, delay lines, and amplitude control elements that are configured to cancel undesired intermodulation products. However, these distributed components result in a bulky and expensive amplifier. Additionally, a typical feed forward amplifier is operational only over a narrow band of frequencies, typically less than 10% bandwidth. In general, the bandwidth of a prior art feed forward amplifier is inherently limited by a distributed solution of the multiple couplers.
Thus, a need exists for a fully integrated monolithic solution of a feed forward amplifier. Furthermore, a need exists for a feed forward amplifier that is compact and cost effective. Also, a need exists for a feed forward amplifier that has a tunable bandwidth across a wide frequency range.


The invention provides a recombinant viral particle for delivering a nucleic acid to mammalian cells, the particle comprising an MLV-env protein that binds to an MLV-env receptor expressed on the surface of a target cell so as to cause infection thereof, and a surface-exposed EGF that binds to an EGF receptor generally not expressed on the surface of the target cell, but expressed on non-target cells that also express the MLV-env receptor, such that binding of the viral particle to the EGF receptor via EGF inhibits infection of the non-target cell by the viral particle.

Retroviral vectors derived from C-type murine leukaemia viruses (MLVs) have emerged as highly versatile gene delivery vehicles and have been selected for use in many human gene therapy protocols, especially those requiring transduction of normal or neoplastic haemopoietic cells. In the interests of safety and efficacy, particularly for direct genetic modification of target cells in vivo, it is desirable that retroviral gene delivery should be accurate but the clinically approved (amphotropic) retroviral vectors in current use attach to an ubiquitously expressed cellular receptor and therefore infect human cells promiscuously. Cell-selective retroviral gene delivery might be achieved by modification of the viral membrane spike glycoproteins responsible for receptor-mediated virus entry.
Retroviral envelope glycoproteins mediate specific viral attachment to cell surface receptors and subsequently trigger fusion between the viral envelope and the target cell membrane. Retroviral envelope glycoproteins consist of an external glycoprotein moiety (SU) noncovalently attached at its C-terminus to a smaller transmembrane polypeptide moiety (TM). Each surface projection (or spike), visible by electron microscopy on the viral surface is a trimer of identical envelope glycoprotein subunits. SU comprises two domains connected by a proline-rich hinge, the N-terminal domain conferring receptor specificity and exhibiting a high degree of conservation between MLV's with different host ranges (Battini et al. 1992 J Virol 66 p1468-1475).
The crystallisation of retroviral SU proteins or their domains remains elusive but sequence alignment of the SU receptor-binding domains of C-type retroviruses reveals a high degree of homology, presumably reflecting a conserved 3-dimensional fold. Two discontinuous hypervariable peptide sequences in this domain, VRA and VRB, have been identified as major determinants of receptor-binding specificity (Battini et al, 1995 J Virol 69 p713-719). Thus it is probable that these receptor binding domains consist of a conserved framework acting as a scaffold for presentation of hypervariable peptide loops which confer binding specificity. According to the "canyon hypothesis", the receptor binding site in SU is likely to take the form of a pocket or groove whose walls and floor may be formed by the residues in VRA and VRB.
Retroviral host range is determined in part by the species and tissue distribution of specific cell surface receptors that are recognised by the viral envelope glycoprotein. Moloney MLV is an ecotropic virus whose envelope attaches to mouse and rat cells but not to human cells. 4070A MLV is an amphotropic virus whose envelope attaches to cells of mouse and human origin. Three C-type retrovirus receptors have now been identified and all are membrane permeases with multiple membrane-spanning domains. In the case of Moloney MLV, the precise target for virus attachment is a constrained peptide loot in the third extracellular domain of the murine cationic amino acid transporter (CAT1) which also functions as a Moloney virus receptor when transplanted into the corresponding site on a homologous human protein (Albritton et al, 1993 J Virol 67 p2091-2096).
Naturally occurring retroviruses incorporate a single species of envelope glycoprotein which mediates specific high-affinity binding to a single well-defined cognate cell-surface receptor. However, additional receptor-binding domains can be incorporated to generate retroviral particles that are capable of binding to more than one species of cellular receptor. Thus, with dual viral infection of a single cell by two enveloped viruses, the host range of either virus may be predictably extended due to promiscuous incorporation of spike glycoproteins encoded by both viruses (Levy, 1976 Virology 77 p811-825; Weiss & Wong, 1977 Virology 76 p826-834; Besmer & Baltimore, 1977 J Virol 21 p965-973; Canivet et al. 1990 Virology 178 p543-541; Lusso et al 1990 Science 247 p848-852: Spector et al. 1990 J Virol 64 p2298-2308; Schnitzer et al, 1977 J Virol 23 p449-454: Metsikko & Garoff, 1989 J Virol 63 p5111-5118; Schubert et al, 1992 J Virol 66 p1579-1589).
Non-viral polypeptide ligands can also be co-incorporated (or pseudotyped) into retroviral vectors with unmodified retroviral envelope glycoproteins. Thus, MHC antigens are incorporated into the envelopes of human and simian immunodeficiency viruses (Gelderblom et al, 1987 Z Naturforsch 42 p1328-1334; Schols et al, 1992 Virology 189 p374-376) mammalian CD4 expressed in avian (quail) cells was incorporated into the envelopes of budding avian retroviruses (Young et al, 1990 Science 250 p1421-1423), a CD4-envelope chimaera, retaining the membrane anchor sequence of the retroviral envelope glycoprotein, was co-incorporated into avian retroviruses with wild type avian retroviral envelope glycoproteins (Young et al. 1990 Science 250 p1421-1423) and a single chain antibody/envelope chimaera was similarly co-incorporated into avian retroviruses (Chu & Dornberg, 1995 J Virol 69 p2659-2663). In the latter example, the host range of the retroviruses was extended to otherwise non-permissive cells that express the tumour antigen recognised by the displayed single chain antibody. A chimaeric Moloney MLV envelope glycoprotein in which the N-terminal domain of SU had been substituted by erythropoietin was co-incorporated into MLV particles with unmodified Moloney envelope glycoprotein (Kasahara et al, 1994 Science 266 )1373-1376). In this example, the authors claimed that the host range of the erythropoietin-displaying viruses was extended to human cells expressing the erythropoietin receptor and that their infectivity was enhanced on mouse fibroblasts that had been transfected with an expression vector coding for erythropoietin receptor. Non-viral polypeptide ligands have also been displayed on retroviruses as N-terminal extensions of a substantially intact Moloney MLV retroviral envelope glycoprotein which retains its receptor-binding domain (Russell et al, 1993 NAR 21 p1081-1085).
In summary, several non-viral polypeptide ligands have been co-incorporated into retroviral vectors with unmodified envelope proteins. The purpose of these manipulations has been to selectively enhance the infectivity of the recombinant retroviruses for cells expressing receptors that are recognised by the non-viral ligand. Selective inhibition of retroviral entry into cells expressing receptors for a displayed non-viral ligand has not previously been proposed, observed or discussed.


Optically active antiviral compounds having the formula ##STR1## wherein m is 0, 1, 2, or 3; n and q are selected from the group of 0 and 1, provided that n and q may not both be zero; and R, R.sub.1, and R.sub.2 are independently of each other selected from the group consisting of oxygen and sulfur, provided that all R, R.sub.1 and R.sub.2, may not be oxygen, and further provided that all R, R.sub.1, and R.sub.2 may not be sulfur. The compounds possess increased antiviral activity and/or metabolic stability.

The full nomenclature of the subject matter of the present invention involves lengthy terms. It is customary for those skilled in the art to abbreviate oligoadenylate analogues and related terms in a manner well-known to the art. These general and customary abbreviations are set forth herein below and may be utilized in the text of this specification.
Abbreviations
2-5A, 2',5'-oligoadenylate or p.sub.3 A.sub.n : Oligomer of adenylic acid with 2',5'-phosphodiester linkages and a 5'-terminal triphosphate group.
A.sub.2, A.sub.3 and A.sub.4 : Dimer, trimer and tetramer of adenylic acid with 2',5'-phosphodiester linkages.
pA.sub.3, ppA.sub.3 (or p.sub.2 A.sub.3), pppA.sub.3 (or p.sub.3 A.sub.3): 5'-terminal mono-, di- and triphosphates of A.sub.3.
pA.sub.4, ppA.sub.4 (or p.sub.2 A.sub.4), pppA.sub.4 (or p.sub.3 A.sub.4): 5'-terminal mono-, di- and triphosphates of A.sub.4.
ApA: Dimer of adenylic acid with 2'-5'-phosphodiester linkage.
Ap*A: Dimer of adenylic acid with 2'-5'-phosphorothioate linkage.
PR: The R stereoconfiguration about a chiral phosphorous atom in a phosphorothioate internucleotide linkage.
PS: The S stereoconfiguration about a chiral phosphorous atom in a phosphorothioate internucleotide linkage.
A.sub.Rp *ApA: (PR)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenosine.
A.sub.Sp *ApA: (PS)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenosine.
ApA.sub.Rp *A: Adenylyl-(2',5')-(PR)-P-thioadenylyl-(2',5')-adenosine.
ApA.sub.Sp *A: Adenylyl-(2',5')-(PS)-P-thioadenylyl-(2',5')-adenosine.
pA.sub.Rp *ApA, ppA.sub.Rp *ApA, pppA.sub.Rp *ApA, pA.sub.Sp *ApA, ppA.sub.Sp *ApA, pppA.sub.Sp *ApA, pApA.sub.Rp *A, ppApA.sub.Rp *A, pppApA.sub.Rp *A, pApA.sub.Sp *A, ppApA.sub.Sp *A, pppApA.sub.Sp *A: 5'-mono-, di- and triphosphates of A.sub.Rp *ApA, A.sub.Sp *ApA, ApA.sub.Rp *A, and ApA.sub.Sp *A.
A.sub.Rp *ApApA: (PR)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenylyl-(2',5')-adenosine.
A.sub.Sp *ApApA: (PS)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenylyl-(2',5')-adenosine. Id.1 ApA.sub.Rp *ApA: Adenylyl-(2',5')-(PR) -P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenosine.
ApA.sub.Sp *ApA: Adenylyl-(2',5')-(PS)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenosine.
ApApA.sub.Rp *A: Adenylyl-(2',5')-(PR)-P-thioadenylyl-(2',5')-adenylyl-(2',5')-adenosine.
ApApA.sub.Sp *A: Adenylyl-(2',5')-adenylyl-(2',5')-(PS)-P-thioadenylyl-(2',5')-adenosine.
pA.sub.Rp *ApApA, ppA.sub.Rp *ApApA, pppA.sub.Rp *ApApA, pA.sub.Sp *ApApA, ppA.sub.Sp *ApApA, pppA.sub.Sp *ApApA, pApA.sub.Rp *ApA, ppApA.sub.Rp *ApA, pppApA.sub.Rp *ApA, pApA.sub.Sp *ApA, ppApA.sub.Sp *ApA, pppApA.sub.Sp *ApA, pApApA.sub.Rp *A, ppApApA.sub.Rp *A, pppApApA.sub.Rp *A, pApApA.sub.Sp *A, ppApApA.sub.Sp *A, pppApApA.sub.Sp *A: 5'-mono-, di- and triphosphates of the above tetramers.
bz: benzoyl PA1 ce: cyanoethyl PA1 CFS: Chronic Fatigue Syndrome PA1 DEAE: 2-(diethylamino)ethyl PA1 DBU: 1.8 diazabicyclo5.3.0!undec-7-enc PA1 HIV: Human Immunodeficiency Virus PA1 MeOTr: monomethoxytrityl PA1 M.O.I: multiplicity of infection PA1 mRNA: Messenger RNA PA1 npe: 2-(4-niytophenyl)ethyl PA1 PBL: Peripheral blood lymphocytes PA1 pCp: Cytidine 3'-5'-bisphosphate PA1 (PS)-ATP-alpha-S: Adenosine 5'O--(PS)-(1-thiotriphosphate). PA1 RNase L: 2-5A-dependent endoribonuclease. PA1 rRNA: Ribosomal RNA PA1 RT: Reverse transcriptase PA1 SCP: Specific cleavage products PA1 tbds: (tert-butyl)dimethylsilyl PA1 Tris: tris(hydroxymethyl)aminomethane PA1 tRNA: Transfer RNA
It is generally regarded that activation of RNase L by 2-5A is key to the antiviral defense mechanisms. Interferon induces transcription of the enzyme 2-5A synthetase which produces 2',5' linked oligoadenylates upon activation of double-stranded RNA. Previously, the only known biochemical effect of 2-5A is activation of RNase L. This enzyme hydrolyses mRNA and rRNA, thereby resulting in inhibition of protein synthesis. The activation of RNase L is transient unless 2-5A is continuously synthesized, since 2-5A is rapidly degraded. RNase L activation thus plays a critical role in inhibiting replication, and therefore in defending against infection by viruses.
A correlation has also been established between 2-5A metabolism and the growth cycle of HIV-1, i.e., high levels of 2-5A and activated RNase L correlate with failure of infected cells to release HIV-1, Schroder et al., J. Biol. Chem. 264: 5669-5673 (1989). Conversely, when the intracellular 2-5A pool decreases, RNase L can not be activated and HIV-1 production increases. A role for 2-5A cores as inhibitors of HIV-1 replication has been established with reports that 2-5A trimer and tetramer cores, 5'-monophosphates and 5'-triphosphates inhibit HIV-1 reverse transcriptase/primer complex formation, Montefiori et al., Proc. Natl. Acad. Sci. USA 86: 7191-7194 (1989); Muller et al., Biochemistry 30: 2027-2033 (1991); Sobol et al., Biochemistry 32: 1211-12118 (1993).
The introduction of the phosphorothioate group in the 2',5'-internucleotide linkages of 2-5A, induces metabolic stability greater than authentic 2-5A and resulted in the first 2-5A cores (i.e. 2-5A lacking 5'-phosphate moieties) able to activate RNase L (Kariko et al. Biochemistry 26: 7136-7142 (1987); Charachon et al. Biochemistry 29: 2550-2556 (1990)). Further, RNase L is a functionally stereoselective enzyme and 2-5A trimers and tetramers having at least one of the internucleotide phosphorothioate 2',5'-linkages of the PS configuration have greatly enhanced metabolic stability. The chemical synthesis of the fully resolved 2',5'-phosphorothioate adenylate trimer and tetramer cores has been reported, Suhadolnik et al., U.S. Pat. No. 4,924,624. Preparation of the stereoisomers via enzymatic synthesis is not possible due to the sterospecificity of 2-5A synthetase for the substrate (PS)-ATP-alpha-S, which yields trimer and tetramer products of the PR configuration exclusively. Further, while Lebleu et al., U.S. Pat. No. 4,981,957, discloses the enzymatic synthesis of a phosphorothioate-substituted derivative of 2',5' oligoadenylate, the compounds disclosed are not stereospecific.

2',5'-phosphorothioate/phosphodiester oligoadenylates and anti-viral uses thereof

Temple University-Of The Commonwealth System of Higher Education


An optical sensing device comprises a photodetector array comprising at least one first photodetector and at least one second photodetector, the photodetector array being arranged on a semiconductor substrate. The optical sensing device further comprises a filter stack arranged on the substrate and covering the photodetector array. The filter stack comprises at least two first lower dielectric mirrors and at least two second lower dielectric mirrors, where a first and a second lower mirror are arranged above the first photodetector and a first and a second lower mirror are arranged above the second photodetector, and where the first lower mirrors have a different thickness in vertical direction which is perpendicular to the main plane of extension of the substrate than the second lower mirrors. The filter stack further comprises a spacer stack arranged on the first and second lower mirrors, and an upper dielectric mirror arranged on the spacer stack and covering the photodetector array. Furthermore, a method for manufacturing an optical sensing device is provided.

The present application relates to an optical sensing device and a method for manufacturing an optical sensing device.
Hyperspectral optical sensing devices can be employed to determine the spectral components of light or of a light source. They can further be employed in color sensing spectroscopy or in chemical analysis. Therefore, these sensing devices comprise several filter channels with wavelength-dependent sensitivities. In this way, a spectral range of several hundreds of nanometers can be covered.
However, existing approaches for hyperspectral optical sensing devices can have the drawbacks of cross talk or overlap between filter channels, a reduced accuracy or a small signal-to-noise ratio.
This disclosure provides an optical sensing device with an improved accuracy. It furthermore provides a method for manufacturing an optical sensing device with an improved accuracy.
In one embodiment of the optical sensing device the optical sensing device comprises a photodetector array comprising at least one first photodetector and at least one second photodetector, the photodetector array being arranged on a semiconductor substrate. The first photodetector and the second photodetector are capable of detecting electromagnetic radiation hitting the photodetector array and reaching the photodetectors. The photodetectors can be for example photodiodes. The photodetectors are arranged next to each other in lateral direction which is parallel to the main plane of extension of the semiconductor substrate. Preferably, the optical sensing device comprises a plurality of photodetectors, for example 16 photodetectors. The semiconductor substrate can comprise a semiconductor material as for example silicon.
The optical sensing device further comprises a filter stack arranged on the substrate and covering the photodetector array. The filter stack comprises at least two first lower dielectric mirrors and at least two second lower dielectric mirrors, where a first and a second lower mirror are arranged above the first photodetector and a first and a second lower mirror are arranged above the second photodetector, and where the first lower mirrors have a different thickness in vertical direction which is perpendicular to the main plane of extension of the substrate than the second lower mirrors. The filter stack is arranged on the photodetector array in vertical direction. The filter stack covers the photodetector array in lateral directions.
The lower mirrors comprise at least two dielectric materials. The lower mirrors can for example be Bragg mirrors. One first lower mirror and one second lower mirror are arranged above the first photodetector in vertical direction. The first lower mirror and the second lower mirror above the first photodetector are arranged next to each other in lateral direction. One further first lower mirror and one further second lower mirror are arranged above the second photodetector in vertical direction. The further first lower mirror and the further second lower mirror are arranged next to each other in lateral direction.
The thickness in vertical direction of the first lower mirrors and the second lower mirrors can be for example at least 500 nm and at most 5 μm. Optionally, the thickness in vertical direction of the lower mirrors is approximately 1 μm. Therefore, the lateral extent of the first lower mirrors and of the second lower mirrors can be kept small, for example at least 30 μm and optionally approximately 50 μm.
The first lower mirrors and the second lower mirrors can each comprise several mirror layers comprising at least two dielectric materials. The total thickness in vertical direction of the mirror layers of the first lower mirrors is different from the total thickness in vertical direction of the mirror layers of the second lower mirrors.
The filter stack further comprises a spacer stack arranged on the first and second lower mirrors. The spacer stack is arranged on the first and second lower mirrors in vertical direction and covers the first and second lower mirrors. The spacer stack can comprise a transparent, dielectric material.
The filter stack further comprises an upper dielectric mirror arranged on the spacer stack and covering the photodetector array. The upper dielectric mirror is arranged on the spacer stack in vertical direction. Preferably, the spacer stack and the upper mirror have the same lateral extent. The upper mirror can be a Bragg mirror.
In an optional embodiment of the optical sensing device the upper mirror and the spacer stack form a Fabry-Perot interferometer with each of the lower mirrors. The spacer stack acts as the etalon. This means, one first lower mirror, the spacer stack and the upper mirror form a Fabry-Perot interferometer. Also one second lower mirror, the spacer stack and the upper mirror form a Fabry-Perot interferometer. Each Fabry-Perot interferometer or filter is a filter channel which passes electromagnetic radiation within a specified wavelength range. The specified wavelength range of each filter channel is given by the properties of the upper mirror, the spacer stack and the lower mirror. For example, the specified wavelength range can be influenced by the thicknesses of the materials of each filter channel. As the thickness in vertical direction of the first lower mirrors is different from the thickness in vertical direction of the second lower mirrors, the specified wavelength range of a filter channel comprising a first lower mirror is different from the specified wavelength range of a filter channel comprising a second lower mirror. Therefore, a first filter channel comprising a first lower mirror passes electromagnetic radiation within a wavelength range that is different from a wavelength range of electromagnetic radiation which is passed by a second filter channel comprising a second lower mirror.
In this way, with the first lower mirrors and the second lower mirrors two different filter channels with different spectral sensitivities are formed. As one first lower mirror and one second lower mirror are arranged above the first photodetector, the first photodetector detects both the electromagnetic radiation passed by the first filter channel and the electromagnetic radiation passed by the second filter channel. Thus, the first photodetector can provide a signal which is the sum of the signal detected by the first photodetector from the first filter channel and the signal detected by the first photodetector from the second filter channel.
Similarly, the second photodetector detects both the electromagnetic radiation passed by the first filter channel and the electromagnetic radiation passed by the second filter channel.
Each lower mirror is set to have a specified center wavelength. The specified center wavelength of a lower mirror is the wavelength in the center of the stop-band of the respective mirror. The stop-band of a Bragg mirror is the wavelength region of high reflectivity. For light with a wavelength being equal or approximately equal to the specified center wavelength of a lower mirror the reflectivity of the respective lower mirror is high. Thus, the center wavelengths of the lower mirrors and of the upper mirror influence which light is passed by the respective filter channel. The specified center wavelength of each mirror can be set by the thicknesses of the mirror layers.
Preferably, the specified center wavelength of the first lower mirror and the specified center wavelength of the second lower mirror differ from each other. The specified center wavelength of the first lower mirror and the specified center wavelength of the second lower mirror can for example differ by 10 nm. Therefore, the transmission spectrum of the first filter channel differs from the transmission spectrum of the second filter channel. For example, the wavelengths of maximum transmission of the first filter channel and of the second filter channel can differ by approximately 3 nm. In this way, the transmission spectra of the first filter channel and the second filter channel are superimposed at the photodetectors. The combined transmission spectrum of the first filter channel and the second filter channel is a superposition of the transmission spectrum of the first filter channel and the transmission spectrum of the second filter channel.
The combined transmission spectrum can yield steep slopes and a wider range of transmitted wavelengths than the first or the second transmission spectrum. The shape of the combined transmission spectrum depends on the reflectivity of the upper mirror and the lower mirrors. The reflectivity determines the steepness of the slopes of the transmission spectra. A higher number of mirror layers in a Bragg mirror enhances its reflectivity, but narrows the range of wavelengths that are passed by the respective filter channel. Therefore, the cross talk between different filter channels can be reduced, but additionally the total intensity of the light passed by a filter channel can be reduced. Advantageously, the combined transmission spectrum of the first filter channel and the second filter channel can exhibit both steep slopes and a wider range of transmitted wavelengths than each filter channel separately.
If the filter channels above the second photodetector differ from the filter channels above the first photodetector the combined transmission spectra are different for both photodetectors.
In an optional embodiment the combined transmission spectra of the different filter channels are different for each photodetector of the photodetector array. The wavelengths of maximum transmission of the different combined transmission spectra can for example be equally spaced within a range of wavelengths. Therefore, the optical sensing device can be employed as a wavelength-selective device. The optical sensing device described here enables to reduce the overlap of the combined transmission spectra of neighboring photodetectors. Therefore, the accuracy of the deconvolution of the signals of the photodetectors and thus the accuracy of the optical sensing device is improved.
In one embodiment of the optical sensing device the thickness in vertical direction of the spacer stack above the first photodetector is different from the thickness in vertical direction of the spacer stack above the second photodetector. In order to achieve a difference in thickness of the spacer stack, the spacer stack can comprise several spacer layers which can comprise a third dielectric material. The spacer layers are arranged in such a way on top of each other that the thickness in vertical direction of the spacer stack is different for each photodetector. Consequently, the thickness of the etalon is different for each Fabry-Perot interferometer. By changing the thickness of the etalon of a Fabry-Perot interferometer the wavelength of maximum transmission of the Fabry-Perot interferometer is changed.
The transmission spectra of the first and the second filter channel are superimposed at the first photodetector. In this way, a first spectral channel of the optical sensing device is formed. The first spectral channel comprises a section of the upper mirror, a section of the spacer stack and a first and a second lower mirror above the first photodetector. A second spectral channel comprises a section of the upper mirror, a section of the spacer stack and a first and a second lower mirror above the second photodetector. Preferably, the optical sensing device comprises several spectral channels. For each spectral channel the thickness of the spacer stack in vertical direction is different.
Consequently, the wavelength of maximum transmission of the first spectral channel is different from the wavelength of maximum transmission of the second spectral channel. Preferably, the thicknesses of the spacer layers of the spacer stack are set in such a way that the wavelengths of maximum transmission of the different spectral channels of the photodetector array are distributed over a range of wavelengths. Preferably, the wavelengths of maximum transmission of the different spectral channels of the photodetector array are uniformly distributed over a range of wavelengths.
For example, the optical sensing device can comprise 16 photodetectors and 16 different spectral channels. In this way, the spectral composition of electromagnetic radiation to be detected by the optical sensing device can be analyzed.
It is also possible that the optical sensing device comprises 48 photodetectors and 48 different spectral channels. A large number of spectral channels enables true color sensing spectroscopy of light and chemical analysis of samples.
Advantageously, the transmission spectrum of each spectral channel has steep slopes and a small full width at half maximum. Therefore, the overlap of or the cross talk between the transmission spectra of different spectral channels is small and the accuracy of the measurement of the optical sensing device is improved.
For forming two filter channels for each photodetector the thicknesses of the first and the second lower mirrors are different from one another. The thicknesses of the first and the second lower mirrors are tuned instead of for example tuning the thickness of the spacer stack for each filter channel because a first and a second lower mirror with different thicknesses can be manufactured more stable and more efficient than a corresponding change of the thickness of the spacer stack.
The third dielectric material can be a high refractive index material. Therefore, the spectral channels are less sensitive to tilted angles of light incidence.
In one embodiment of the optical sensing device the lower mirrors comprise first mirror layers comprising a first dielectric material and second mirror layers comprising a second dielectric material with a second refractive index being different from a first refractive index of the first dielectric material, where the first mirror layers and the second mirror layers are arranged alternatingly. For example, the first refractive index can be larger than the second refractive index. It is also possible that the first refractive index is smaller than the second refractive index. The first dielectric material can be for example TiO2, Ta2O5 or Nb2O5 and the second dielectric material can be for example silicon oxide. If the specified center wavelength of a lower mirror is in the infrared range the first dielectric material can be amorphous silicon or hydrogenated amorphous silicon.
In one embodiment of the optical sensing device the setup of the first filter channel is as follows:
At first, a dielectric layer comprising the first dielectric material is deposited. On top of the dielectric layer the first lower mirror is deposited. The first lower mirror comprises alternating mirror layers, where the first mirror layer comprises the first dielectric material and the second mirror layer comprises the second dielectric material. The first mirror layer is deposited on top of the dielectric layer and the second mirror layer is deposited on top of the first mirror layer. The first lower mirror can for example comprise at least three and at most six pairs of alternating mirror layers. The spacer stack is arranged on the first lower mirror and comprises the third dielectric material with a high refractive index. The upper mirror is deposited on the spacer stack. Similar to the first lower mirror the upper mirror comprises pairs of alternating mirror layers. A second mirror layer comprising the second dielectric material is deposited on the spacer stack. A first mirror layer comprising the first dielectric material is deposited on the second mirror layer. On top of the upper mirror a further dielectric layer comprising the first dielectric material is deposited.
The only difference to the second filter channel is that the second filter channel comprises the second lower mirror instead of the first lower mirror.
By depositing the dielectric layer and the further dielectric layer the signal to noise ratio of the respective filter channel is improved.
In one embodiment of the optical sensing device at least some of the first mirror layers and at least some of the second mirror layers of the lower mirrors have a thickness corresponding to an optical thickness being equal to one quarter of a specified center wavelength. Preferably, at least some of the first mirror layers and at least some of the second mirror layers of the upper dielectric mirror have a thickness corresponding to an optical thickness being equal to one quarter of a specified center wavelength of the upper mirror.
The thicknesses of the mirror layers of the lower mirrors and of the mirror layers of the upper mirror are different and consequently the specified center wavelength is different for the lower mirrors and for the upper mirror. Preferably, the specified center wavelength of the upper mirror is larger than the specified center wavelength of the first lower mirror and smaller than the specified center wavelength of the second lower mirror.
In one embodiment of the optical sensing device the first lower mirror has a first stop-band and the second lower mirror has a second stop-band. The first stop-band can be different from the second stop-band. That the stop-bands of the first lower mirror and the second lower mirror are different from each other means that the specified center wavelength is different for the first and the second lower mirror. Because of the different stop-bands the transmission spectra of the first filter channel and of the second filter channel are different.
In one embodiment of the optical sensing device a first center wavelength of the first stop-band is given by the thickness of the mirror layers of the first lower mirror and a second center wavelength of the second stop-band is given by the thickness of the mirror layers of the second lower mirror. The first center wavelength of the first stop-band is the wavelength in the center of the first stop-band. The second center wavelength of the second stop-band is the wavelength in the center of the second stop-band. Therefore, the stop-bands of the lower mirrors influence the transmission spectrum of the respective filter channel.
In one embodiment of the optical sensing device the first center wavelength and the second center wavelength are different from one another. Therefore, the transmission spectra of the first filter channel and of the second filter channel are different from one another.
In one embodiment of the optical sensing device the first center wavelength differs from the second center wavelength by at least 1 nm and at most 30 nm. For these small differences between the center wavelengths the superposition of the transmission spectra of the first filter channel and of the second filter channel is a combined transmission spectrum with steep slopes and a small full width at half maximum. Therefore, the spectral sensitivity of the optical sensing device and thus the accuracy of the measurement of the optical sensing device are improved.
In one embodiment of the optical sensing device the first photodetector and the second photodetector comprise two sub-photodetectors, respectively, where the sub-photodetectors are arranged next to each other in lateral direction which is parallel to the main plane of extension of the substrate. For each photodetector one sub-photodetector is arranged to detect electromagnetic radiation passed by the first filter channel and a further sub-photodetector is arranged to detect the electromagnetic radiation passed by the second filter channel. Instead of combining the signals of the two filter channels with one photodetector, the signals of the sub-photodetectors are added. In this way, the combined transmission of the first and the second filter channel can be determined.
In one embodiment of the optical sensing device a decoupling layer covering the photodetector array is arranged on the upper mirror. Preferably, the decoupling layer has the same lateral extent as the upper mirror. The decoupling layer is arranged on the upper mirror such that a bandpass filter can be arranged on the decoupling layer. In that case the decoupling layer decouples the bandpass filter optically from the Fabry-Perot filter. The decoupling layer can comprise a dielectric material.
In one embodiment of the optical sensing device a bandpass filter covering the photodetector array is arranged on the upper mirror. Preferably, the bandpass filter is arranged on the decoupling layer and has the same lateral extent as the decoupling layer. It is also possible that the bandpass filter is directly arranged on the upper mirror. The bandpass filter has a pass-band within which electromagnetic radiation is passed. Moreover, the bandpass filter has a stop-band within which electromagnetic radiation is blocked or attenuated.
The bandpass filter can be employed to prevent unwanted light from reaching the photodetector array. For example, if the filter channels of the filter stack do not block light in some wavelength regions, an additional bandpass filter can be employed. The pass-band of the bandpass filter extends over the region of wavelengths that are passed by the filter channels. The transmission of the bandpass filter in the region of wavelengths that are passed by the filter channels can be close to 100%. Furthermore, the transmission of the bandpass filter within the stop-band of the upper mirror and the lower mirrors can be close to 100%. Electromagnetic radiation outside of the pass-band of the bandpass filter is suppressed by the bandpass filter. The bandpass filter can be a dielectric bandpass filter.
The decoupling layer is arranged between the upper mirror and the bandpass filter in order to decouple the filter channels from the bandpass filter. The thickness of the decoupling layer is set according to the following relation:
      d    =                  (                              ϕ                          u                            p                                +                      ϕ                          B                            P                                      )            2        ,where d is the optical thickness of the decoupling layer, and ϕup and φBP are the phase changes of passing light due to the reflection on the upper mirror and on the bandpass filter, respectively. Consequently, the total transmission through the bandpass filter and the filter channels is the product of the transmission of the bandpass filter and the transmission of the respective filter channel.
The upper mirror, the decoupling layer and the bandpass filter can have the same lateral extent. Therefore, the upper mirror, the decoupling layer and the bandpass filter can be patterned with only one mask.
It is also possible that the optical sensing device comprises several photodetector arrays with different spectral sensitivities and different bandpass filters in order to detect a large range of wavelengths.
In one embodiment of the optical sensing device the spacer stack comprises a first spacer layer comprising a third dielectric material and a second spacer layer comprising the third dielectric material, where a first segment of the second spacer layer is arranged on the first spacer layer and covers the second photodetector but not the first photodetector. Therefore, the thickness in vertical direction of the spacer stack above the first photodetector is different from the thickness in vertical direction of the spacer stack above the second photodetector. By employing the first spacer layer and the second spacer layer the different thicknesses of the spacer stack can be manufactured efficiently.
In one embodiment of the optical sensing device the photodetector array comprises four photodetectors and the first spacer layer covers all four photodetectors. The second spacer layer only covers the third and the fourth photodetector. A first segment of a third spacer layer covers the second photodetector and a second segment of the third spacer layer covers the fourth photodetector. In this way, the thickness of the spacer stack is different for each photodetector. For manufacturing the spacer stack 2N different thicknesses of the spacer stack are formed by N masking steps. Therefore, the spacer stack can be formed more efficiently than by depositing the required thickness of the spacer stack for each photodetector separately.
In one embodiment of the optical sensing device a first spectral channel is formed by one first lower mirror, one second lower mirror, a section of the spacer stack covering the first photodetector and a section of the upper mirror covering the first photodetector, and a second spectral channel is formed by one first lower mirror, one second lower mirror, a section of the spacer stack covering the second photodetector and a section of the upper mirror covering the second photodetector. The transmission spectrum of the first spectral channel is different from the transmission spectrum of the second spectral channel. Therefore, the photodetector array can detect different spectral components of electromagnetic radiation to be analyzed.
In one embodiment of the optical sensing device the first and the second photodetector are configured to detect light incident on the optical sensing device and passing through the upper mirror, the spacer stack and the two lower mirrors. The light to be detected by the optical sensing device can for example be in the visible or mid infrared range.
Furthermore, a method for manufacturing an optical sensing device is provided. The optical sensing device can optionally be produced by means of one of the methods described herein. This means all features disclosed for the optical sensing device are also disclosed for the method for manufacturing an optical sensing device and vice-versa.
According to at least one embodiment of the method for manufacturing an optical sensing device, the method comprises the step of providing a photodetector array arranged on a semiconductor substrate, where the photodetector array comprises at least one first photodetector and at least one second photodetector. The first photodetector and the second photodetector are arranged next to each other in a lateral direction which is parallel to the main plane of extension of the semiconductor substrate. Preferably, the photodetector array comprises a plurality of photodetectors. The photodetectors are capable of detecting electromagnetic radiation and they can be for example photodiodes.
The method for manufacturing an optical sensing device further comprises the step of depositing a first lower dielectric mirror above each photodetector in a vertical direction which is perpendicular to the main plane of extension of the substrate by employing a first mask. The first lower mirror can comprise several mirror layers. The mirror layers are deposited through the first mask. The first mask is structured in such a way that above each photodetector one first lower mirror is deposited. The mirror layers can be deposited or sputtered.
The method for manufacturing an optical sensing device further comprises the step of depositing a second lower dielectric mirror above each photodetector in vertical direction by employing a second mask, where the first lower mirror and the second lower mirror of each photodetector are arranged next to each other in a lateral direction which is parallel to the main plane of extension of the substrate and where the first lower mirrors have a different thickness in vertical direction than the second lower mirrors. The second lower mirror can comprise several mirror layers. The mirror layers are deposited through the second mask. The second mask is structured in such a way that above each photodetector one second lower mirror is deposited. The mirror layers can be deposited or sputtered.
The method for manufacturing an optical sensing device further comprises the steps of depositing a spacer stack arranged on the first and second lower mirrors, and depositing an upper dielectric mirror arranged on the spacer stack and covering the photodetector array.
For the optical sensing device manufactured by the method described here the overlap of or the cross talk between the transmission spectra of different spectral channels is small and the accuracy of the measurement of the optical sensing device is improved.
According to at least one embodiment of the method for manufacturing an optical sensing device the thickness in vertical direction of the spacer stack above the first photodetector is different from the thickness in vertical direction of the spacer stack above the second photodetector. Therefore, the first spectral channel is formed above the first photodetector and the second spectral channel is formed above the second photodetector. The transmission spectrum of the first spectral channel is different from the transmission spectrum of the second spectral channel. Therefore, the photodetector array can detect different spectral components of electromagnetic radiation to be analyzed.
According to at least one embodiment of the method for manufacturing an optical sensing device, depositing the spacer stack comprises depositing a first spacer layer on the first and second lower mirrors, where the first spacer layer comprises a third dielectric material, depositing a second spacer layer on the first spacer layer, where the second spacer layer comprises the third dielectric material, and structuring the second spacer layer by employing a third mask such that a first segment of the second spacer layer covers the second photodetector but not the first photodetector. This method can be employed to form a spacer stack for a photodetector array with a plurality of photodetectors. By employing N masks 2N different thicknesses of the spacer stack for 2N photodetectors can be formed. As only N masks are required to form 2N different thicknesses the optical sensing device can be manufactured efficiently.

Optical sensing device and method for manufacturing an optical sensing device


A portable parking meter including a main device and at least a sub-device; The body of the main device has two inserting slots for some sub-devices and is provided on the front face thereof with a control panel, the inserting slots are provided with some card interfaces capable of communicational connection with the main device when the sub-devices insert therein; The main device has a CPU which uses a reset loop connected peripherally with a keyboard interface, an oscillating loop and a LCD loop, and which has its internal timing program to establish the communication between it and the sub-devices, and it can count sequentially by the rate of value preset in the sub-devices for timing or reckonning times and deducting amount of charges in the sub-devices as a parking fee.

The present invention relates to the structural device of a portable parking meter comprising principally a main device capable of being inserted by and having communication with at least one sub-device. When in communication, it can count sequentially by the rate of value preset in the sub-devices and choose a kind of calculating unit for reckonning charges as a parking fee.
The traditional parking meters now available are mechanical meters fixedly installed at the parking positions of cars, and because the mechanical structures thereof are subjected to the affection of humidity as well as vibration leading to failure; such failure bothers frequently the users of the old fachsioned meters, while it is not easy to be solved, this is a big disadvantage resided in today's parking fee system. In this view, it is wanted pressingly to design a simple as well as portable parking meter to get rid of the defects of the existing meters.


A method and abrasive blast medium for cleaning contaminants from electronic hardware. The abrasive blast medium is a pure, water soluble alkaline salt of bicarbonates and carbonates. The particle size of the alkaline salts range from about 20 to no larger than about 300 microns in diameter. The Mohs hardness of the alkaline salt particles is no greater than about 5.0. The blast cleaning conditions employed to clean the electronic hardware are mild. Blast air pressures range from about 10 to about 50 psi and the medium flow rate ranges from about 1 to about 10 lbs/min.

The present invention is directed to a method of blast cleaning electronic hardware components. More particularly, the method of the present invention is directed to cleaning electronic hardware components by blast cleaning with a water soluble abrasive media under mild conditions.
Electronic hardware components include any conductive, semiconductive or dielectric part used in electronic apparatus such as computers and the like. Such hardware components include, but are not limited to, electronic components of circuit and wiring boards, semiconductor wafers from which semiconductor chips are made, and disk drive heads and the like.
The cleanliness of electronic hardware components is regarded as being critical to their functional reliability. Contaminants on the electronic hardware components can cause shorts in the electronic hardware components and interfere with the operation of the electronic components such that the electrical functions of an electronic apparatus in which they are employed become unreliable.
In the manufacture of electronic hardware components, contaminants can accumulate after one or more steps of the manufacturing process as well as during the assembly of the components into an electronic apparatus. During the manufacturing process, electronic hardware components can be plated, etched, handled by operators during assembly steps, coated with corrosive or potentially corrosive fluxes and the like. Thus it is important that such contaminants be removed from the components. However, certain methods used to clean electronic hardware components can present undesirable problems of their own.
For example, in the fabrication of electronic circuit assemblies, e.g., printed circuit boards, soldering fluxes are first applied to the substrate board material to ensure firm, uniform bonding of the solder. These soldering fluxes fall into two broad categories: rosin and non-rosin, or water soluble, fluxes. The rosin fluxes which are generally only moderately corrosive and have a much longer history of use are still widely used throughout the electronics industry. The water soluble fluxes which are a more recent development are being used increasingly in consumer products applications. Because water soluble fluxes contain strong acids and/or amine hydrohalides, such fluxes are very corrosive. Unfortunately, residues of any flux can cause circuit failure if residual traces of the material are not carefully removed following soldering and thus remain on an electronic circuit assembly.
While water soluble fluxes can be easily removed with warm, soapy water, the removal of rosin flux from printed circuit boards is more difficult and has therefore traditionally been carried out with the use of chlorinated hydrocarbon solvents such as 1,1,1-trichloroethane, trichloroethylene, trichloromonofluoromethane, methylene chloride, trichlorotrifluoroethane (CFC113), tetrachlorodifluoroethane (CFC112) or mixtures or azeotropes of these and/or other solvents. These solvents are undesirable, however, because they are toxic and when released into the environment deplete the ozone layer and/or contribute to the greenhouse global warming effect. Thus, use of such solvents is subject to close scrutiny by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA), and stringent contaminant equipment must be used. Moreover, if released into the environment these solvents are not readily biodegradable and are thus hazardous for long periods of time.
Alkaline cleaning compounds known as the alkanolamines, usually in the form of monoethanolamine, have been used for rosin flux removal as an alternative to the toxic chlorinated hydrocarbon solvents. These high pH compounds (e.g., about pH 12), chemically react with rosin flux to form a rosin soap through the process of saponification. Other organic substances such as surfactants or alcohol derivatives can be added to these alkaline cleaning compounds to facilitate the removal of such rosin soap. Unfortunately, these compounds, as well as the water soluble soldering fluxes, have a tendency to cause corrosion on the surfaces and interfaces of printed wiring boards if such compounds and fluxes are not completely and rapidly removed during the fabrication process.
The complete removal of adhesive and other residues also pose a problem. During the manufacture of electronic circuit assemblies the components are mounted on the upper surface of the board with leads protruding downwardly through holes in the board and are secured to the bottom surface of the board by means of an adhesive. Further, it is sometimes necessary to temporarily protect certain portions of the circuit board by the application of special adhesive tape to susceptible areas. Once such protection is no longer needed, the adhesive tape must be removed. In both instances, a residue of adhesive generally remains which, if not thoroughly removed, can cause premature board failure. Removal of this adhesive residue has traditionally been carried out by the use of chlorinated solvents which, as already described, are toxic and environmentally undesirable.
In addition to soldering fluxes, any photoresist used in etching and screen printing of components on circuit and wiring boards can also cause short circuiting problems. U.S. Pat. No. 5,145,717 to Drury and assigned to E. I. Du Pont de Nemours and Company discloses a method of blast cleaning printed circuit boards of photoresist with an abrasive. The method employs polymeric or resin material having a Mohs scale hardness of about 2 to 4. The particles are accelerated at the surface of the board at an angle of about 15 to 90 degrees by means of a blasting apparatus to remove the photoresist. Although the method may remove photoresist from circuit and wiring boards, the polymer particles used to remove the photoresist can not be easily removed from the blasted surface. Moreover, the polymer particles can become embedded in the blast cleaned surface, or lodged in dead areas,i.e., corners or recesses of the surface, where it is very difficult to remove the polymer particles. Also, the photoresist can not be readily disposed of by sewering. Such particles would pollute the environment.
Similar contaminant problems also occur with disk drive heads. During assembly of computer terminals, such contaminants as adhesive and finger prints can contaminate the drive heads and result in compromised performance of the electronic apparatus.
As with the electronic components of circuit and wiring boards, and disk drive heads, it is important that semiconductor wafers and chips are as clean as possible before the semiconductor material is incorporated into any electronic apparatus. Any contaminants on the semiconductor material can jeopardize the optimum performance of the electronic apparatus. Consequently, such contaminants as oxidation compounds and laser slag formed on semiconductor wafers during manufacture preferably are removed prior to dicing or cutting the semiconductor wafers into semiconductor chips.
Blast cleaning of semiconductor wafer surfaces has been previously used to wash electrostatic particles from the surface. One such method utilizing water is disclosed in U.S. Pat. No. 4,027,686 to Shortes et al. and assigned to Texas Instruments, Inc. Other fluids, including air, have been used with varying degrees of success. Although various methods have been employed to clean contaminants from electronic hardware components, there is still a need for a mild and environmentally friendly method to clean such contaminants as photoresists, solder flux, adhesives, oxidized material, laser slag and the like from electronic hardware components.
It is known to blast clean soft surfaces of aluminum, magnesium, and plastic surfaces to remove paint and dirt with such abrasives as sodium chloride and sodium bicarbonate. However, in order to maintain the flow of such abrasives as sodium bicarbonate, flow aids such as hydrophobic silica are often employed. Such flow aids, however, can leave additional deposits on the surface of electronic components being cleaned. Such deposits when formed on electronic hardware components are not only difficult to remove even with high pressure water rinses, but replace one type of contaminant with another.
A primary object of the present invention is to provide a method of blast cleaning contaminants from electronic hardware components by blast cleaning the contaminants from the surface of electronic components under mild conditions.
Another object of the present invention is to blast clean the surface of electronic hardware components using relatively low pressures.
A further object of the present invention is to provide a method of blast cleaning contaminants from electronic components with environmentally friendly abrasives.
Still yet another object of the present invention is to blast clean electronic hardware components with a water soluble abrasive media.
Other objects and advantages of the present invention will become apparent to those of skill in the art upon reading the description of the present invention which follows and practicing the present invention.

Method for cleaning electronic hardware components


A razor having a handle and a blade cartridge containing one or more blades includes an electric circuit with a battery power source for controlled direction of current flow through the one or more blades in order to heat the blades. The electric circuit further includes opposing electrically conductive contact leads, the battery power source, and an electrically conductive contactor in contact with an ON/OFF switch all housed on the blade cartridge. A housing for the battery and switch extends transversely in spaced and separated relation to the blades and defines a bridge structure over an open gap between the housing and the blades for allowing a directed stream of water flow to pass below the housing, through the gap and between the plurality of electrically conductive blades for rinsing debris from surfaces of the blades.

1. Field of the Invention
The present invention relates generally to razors for shaving and, more particularly, to a battery powered system in a razor for heating of one or more blades of the razor.
2. Discussion of the Related Art
It is well known that hairs are softened and easier to cut when they are heated just prior to being cut by the sharp cutting edge of a razor blade. It is also known that the cutting edge of the razor blade is more effective in cutting hairs when the blade is warm or hot. Just prior to shaving, most people warm the hairs and skin with hot water or a hot towel. It is also common practice to place the shaver under hot running water in order to heat the blades just prior to stroking the blades over the skin in order to cut the hairs. However, the heat cutting performance of the blades lasts only a short time during the beginning of the shaving stroke. Within seconds, the temperature of the skin surface, hairs and blade are quickly reduced due to exposure to the ambient air temperature. Ideally, it is best to maintain the blades warm or hot throughout the shaving process.
The present invention provides for a heat controller for allowing the user to selectively adjust the heated temperature of the blades for desired comfort and optimum blade cutting efficiency. A further improvement provides for a total "onboard" heating system in a disposable blade cartridge, inclusive of an on/off switch, thereby providing for controlled heating of blades in disposable blade cartridges for use on conventional razor handles. A further improvement which may be provided by the present invention is an automatic turn-off switch, in addition to the user controlled on/off switch, for automatically turning the heating system off after use of the razor in the event the user fails to operate the on/off switch, thereby preserving battery life.


A dual regeneration bandgap voltage generator circuit includes both CMOS and bipolar regeneration bandgap voltage generator circuits. Each of the regeneration bandgap voltage generator circuits is formed by cross-coupling current mirror circuits of opposite conductivity types. Upon initial application of power, the CMOS circuit becomes active first due to its higher leakage current. The "on" current from the CMOS circuit is then used to initiate current conduction within the bipolar circuit. Once the bipolar circuit begins operating, it turns the CMOS circuit off.

1. Field of the Invention
The present invention relates to bandgap reference voltage generator circuits, and in particular, to bandgap reference voltage generator circuits using current regeneration techniques.
2. Description of the Related Art
Bandgap reference voltage generator circuits come in a variety of configurations and can be implemented using either, or both, bipolar or metal oxide semiconductor (MOS) transistors. For example, such a circuit can be implemented in a bipolar and complementary MOS (BiCMOS) process and designed to require less than 100 nanoamperes of supply current from the power supply voltage VCC source.
Referring to FIG. 1, one conventional bipolar circuit uses two current mirror circuits Q1/Q2, Q3/Q4 cross-coupled in a telescopic circuit configuration. Hence, the input I1 and output I2 currents of the PNP current mirror circuit Q1/Q2 serve as the output and input currents, respectively, of the NPN current mirror circuit Q3/Q4. Transistor Q2 is typically scaled with a larger emitter area than transistor Q1 (e.g., 3:1), and transistor Q4 is typically scaled to have an emitter area larger than that of transistor Q3 (e.g., 10:1). The resulting bandgap voltage VBG is typically designed to be 1.2 volts.
Frequently, the most important operating characteristic for this type of circuit is its startup characteristic. For example, a fast rise time in the power supply voltage VCC will start it up. However, startup may not occur if the power supply voltage VCC is increased slowly and the temperature is very low (e.g., -55.degree. C.). This is due to the fact that the low current beta characteristic of the transistors Q1, Q2, Q3, Q4 is often too low to support sufficient leakage current to provide the current regeneration process necessary at very low temperatures, particularly over variations in the manufacturing processes. Further, even if the circuit initially starts up properly, in the event that the power supply voltage VCC drops low enough to shut down the circuit, the circuit may not turn back on once the supply voltage VCC has been returned to its correct value.
Referring to FIG. 2, a different situation is encountered when CMOS devices replace the bipolar devices. (This circuit is similar to that of FIG. 1 in that it is formed of a PMOS current mirror circuit M1/M2 cross-coupled with an NMOS current mirror circuit M3/M4 in a telescopic circuit configuration.) Transistors M2 and M4 are typically scaled to have wider channel dimensions than transistors M1 and M3, respectively (e.g., 3:1). Even at very low temperatures, the leakage current through a MOS transistor is not zero, notwithstanding the sophisticated processes presently used in fabricating the devices. Either the NMOS or PMOS devices are going to leak more than the other devices.
For example, in the event that the NMOS transistor leak more, the leakage current in transistor M4 will cause the PMOS transistors M1, M2 to turn on (due to the biasing of the gate-source region of transistor M1 caused by the leakage current through transistor M4). As the voltage drop across the gate-source region of transistor M1 increases, current I1 increases. As current I1 increases, current I2, which is a scaled-up replica of current I1, causes the voltage potential at the gate terminals of transistors M3 and M4 to increase. This process continues until a sufficiently large current I1 flows through a resistor R2 to cause the loop gain to become unity. (It will be understood that if, instead, the PMOS transistors Ml, M2 had higher leakage currents than the NMOS transistors M3, M4, this same current regeneration process would take place.)

Dual regeneration bandgap reference voltage generator