The invention relates to a software defined device interface system 10, a software defined device interface, gateway and a method of defining an interface for a device which uses a specific communication protocol for communication purposes. The system 10 includes a microprocessor/processing unit 12.1, 12.2 with a plurality of communication pins and software/firmware. The software/firmware is configured, based on a specific communication protocol which is used by a particular device 30.1-30.4 for communication purposes, to, in runtime, assign/select one or more of the communication pins to form a virtual port to which the particular device 30.1-30.4 can be connected, upon receiving a configuration instruction from a user to implement the specific communication protocol. The software/firmware is further configured to implement the specific communication protocol through the virtual port, to thereby allow for communication between the microprocessor/processing unit 12.1, 12.2 and the device 30.1-30.4, when the device 30.1-30.4 is connected to the pin(s) of the virtual port.

The "Internet of Things" (IoT) is a technical term in the IT industry, where billions of devices are going to be connected to various Internet servers/Cloud Services. Although a portion of devices are sufficiently intelligent (for example IP based), and can be directly connected to the cloud, there are a lot of legacy or potential new low cost devices that can be connected ("digitised") onto an IP based platform, via an edge gateway.
Currently it is believed by the Inventor that IoT could be implemented in the following markets:                1. Consumers (Home Automation);        2. Commercial (Examples include Building Management, Access Control, Security, Safety, Environmental Monitoring, Transportation, Utility metering, Asset Tracking etc.);        3. Industrial (Examples include manufacturing, supervisory control and data acquisition (SCADA), etc.);        4. Mining: To monitor previously (invisible area) unconnected equipment behaviour in underground/harsh environments; Weightometers; yellow equipment; etc.;        5. Telecommunications Industry;        6. Government or Military;        7. Vehicle Monitoring (For example, the predictive maintenance of vehicle components); and        8. Logistics and transportation (For example, vehicle tracking, fuel management, security, etc.).
Depending on the purpose of the controller (or "Edge Gateway") and the types of external devices that were catered for by the hardware designer, the groupings of processor pins are usually routed on printed circuit boards (PCB's) to a set of fixed number of exposed physical industry standard connectors, such as:                Ethernet: Dedicated RJ-45 (on embedded PC's, "Edge Gateways" and PLC's (programmable logic controller), etc.),        UART (universal asynchronous receiver/transmitter): for example a DB9 serial port (on embedded PC's or "Edge Gateways", etc.),        CAN (Controller Area Network) bus: OBD-II (on vehicles, etc.), and        SPI (Serial Peripheral Interface) or I2C (Inter-Integrated Circuit): Dedicated Screw Terminals or Header Pins (on "Edge Gateways" or Raspberry Pi's).
The following communication protocols are currently used in the industry to connect to devices or sensors:                1. IP (Internet Protocol) based devices.        2. Dedicated hardware port/interface, such as TTL Serial, RS-232, RS-485, USB, SPI, I2C, CAN bus or Ethernet ports.        3. Binary Inputs (to detect a 3.3 VDC/5 VDC Voltage on a GPI processor pin). Examples include:                    An external Push Button pressed by a person to open a door by closing a Normally Open (N/O) switch, connected to a Common (C) reference,            A magnetic Door Positioning Sensor, which opens a Normally Closed (N/C) circuit when the door is opened,            A Passive Infrared Sensor, which regulates an output Voltage when movement is detected,            A Smoke Detection Sensor, which regulates an output Voltage when smoke is detected,            A weightometer that triggers a relay that is connected to an Odometer-like mechanical counter that displays the actual cumulative tonnages to a human operator or HMI (human machine interface).                        4. Binary Outputs (to output a 3.3 VDC/5 VDC Voltage on a GPO processor pin). Examples include:                    To energise a relay coil that opens or closes solenoid that switches an isolated VAC or VDC power circuit that provides power to an external device such as a gate motor or siren which causes the device to be switched On or Off.                        5. PWM (to generate a variable digital signal frequency on a GPO processor pin). Examples include:                    To control the speed of a variable stepper motor,            To generate audio frequencies on audible devices for sound production.
Currently, all of the above can be accomplished by utilizing various different dedicated ports on existing controllers, such as PLCs, industrial embedded computers, Arduino, Raspberry Pi or commercial/industrial "Edge Gateways".
The standard way of connecting non-IP based devices to the cloud, are with what is termed "Edge Gateways". These Gateway devices usually can connect devices with some level of intelligence via dedicated hardware ports (e.g. RS232, RS485, USB, CAN bus, I2C). Some companies (for example Cisco, Dell & Samsung) are selling "Edge Gateways" that sits on premise ("at the edge") close to the sensors/devices. These gateways then communicate via various standards (GSM/Ethernet/WiFi/Long Range Wireless) to a cloud solution which usually consist of a combination of "Big Data", "Analytics", Machine Learning and mobile devices (such as smart phones or tablet) to analyse the data after the event and to generate alerts.
The main purpose of these IoT/Edge Gateways, are to connect to various non-IP based devices and sensors, filter/aggregate sensor values and to then push this data to the cloud, instead of having sensors that are directly connected to the cloud. Examples are temperature/humidity sensors and accelerometers, vibration sensor, etc. Some of these non-IP-based devices typically include 1-wire, 2-wire, I2C, SPI and CAN bus interfaces that cannot be connected to a IP-based network switch or router directly and requires a specific physical layer protocol to interrogate and control these devices. Cisco Systems has also coined the term "Fog Computing" for their edge routers (as opposed to "Cloud Computing") meaning intelligence has moved closer to the edge.
To date, all the industrial Edge Gateways that are sold, usually imply a device that has a Linux or Windows operating system, which can then be programmed to accumulate various sensors/device data via dedicated ports or detect simple inputs or emit simple outputs. Proprietary firmware/embedded devices also exist, with limited number of dedicated connectors for devices or sensors to plug into.
FIG. 1 shows a few examples of edge gateways with different connection interfaces. In order to add new device interfaces, the product needs to be redesigned (including hardware and enclosure) or various models must be introduced. FIG. 2 shows an example of a gateway with a CAN bus interface only. FIG. 3 shows a Gateway enclosure with various different connection interfaces.
The cost-factor plays a major role in deciding the functionality of a dedicated edge gateway design. There is a trade-off between low-cost controllers with a very limited number of interfaces vs over-engineered controllers which are very expensive and are not guaranteed to be future proof in terms of new connectors or protocols.
The inventor wishes to address at least some of the problems identified above.

Software-defined device interface system and method


The invention relates to a file shredder with a device for detecting metallic objects introduced into the paper feed of the file shredder, a cutting unit with rotating cutting tools, a motor for driving the cutting tools and a transmission device for connecting the motor to the rotating cutting tools. According to the invention, substantially all of the metallic components of the cutting unit of the file shredder surrounding the rotating cutting tools, the motor and the transmission device are connected with one another in an electrically conducting manner such that they lie on a common defined electric potential.

In order to prevent damage to the cutting unit by metal parts such as e.g., paper clips, staples or the like introduced into the paper feed, some file shredders nowadays have a metal detector. This metal detector usually comprises a sensor device which reacts to metal introduced into the paper guide and switches off the cutting unit and/or the paper feed of the file shredder before the metal parts can come into contact with the cutting elements of the cutting unit.
The mode of operation on which the corresponding metal-detecting sensor device is based is hereby based on the methods generally used for detecting/recognizing metal, such as, for example, pulse measurements based on induction or alternating current measurements.
Due to the small size of the metal object to be detected, and the resulting low signal level, in practice the problem arises with the file shredders according to the prior art that the signal-to-noise ratio is very small, so that a reliable detection of small metal parts is not given.


Sensitometric Quality Indicator Parameters (SQIP), including Color Radial Error (1), Average Density Error (2), Contrast Mismatch Error (3), HUE (4), and related Auxiliary Quality Parameters, are derived primarily from the deviations in aim values of the red, green, and blue density values over the standard range of exposure steps for a color photographic product. Normalized tolerance limit values common to SQIP 1-3 are established at one exposure reference level within the standard range of exposure steps. A composite graphical display of density deviations versus LOG H exposure, of SQIP 1-4 with associated tolerance limit values versus LOG H exposure, and of the Auxiliary Quality Parameters enables the rapid analysis and disposition of a batch of color photographic product with regard to sensitometric quality. By incorporating selected Auxiliary Quality Parameters, custom-weighted for a specific product, a quality objective function provides the basis for estimating and implementing prescriptive changes in the set points of calibrated process control variables to improve sensitometric quality.

Light sensitive, silver halide based color photographic products typically comprise a number of constituents in each of their successive layers. The physical grain sizes, chemical structures and chemical compositions of the constituents, as well as the manufacturing process and apparatus used to supply the constituents and apply the layers, can have profound effects on the sensitometric properties or characteristics of the product upon exposure and subsequent development. Thus, variations in such parameters during manufacture of a product can lead, for example, to totally unacceptable products which must be scrapped at considerable expense to the manufacturer or to undesirable variations from run to run of a product which make use of the product difficult for the customer.
One known approach to controlling the sensitometric characteristics of a product has been to sample the product during manufacture; expose it in a controlled manner, and then develop or process it to permit such characteristics to be measured and any necessary manufacturing process or product constituent changes to be made. The red, green and blue density curves have been plotted and then compared to previously determined aim responses for the particular product. A high degree of skill has been required for the reader of such curves to make such comparisons at several points for each color, for such parameters as the speed response, the contrast, the density, the stain limit and the color balance; and then to decide how to adjust the product or the manufacturing process to produce product within acceptable limits. While such analysis has been done, the production process either has been stopped awaiting test results or has continued running on the assumption that the results would be acceptable. In the former instance, undesirable delays in production have resulted; while in the latter instance, substantial quantities of product have been scrapped when the result were not acceptable.
A similar approach to such a problem is disclosed by U.S. Pat. No. 3,990,898 which teaches an empirical method to adjust the color speed balance of a photographic film using filter dyes. Aim values are established for acceptable color speed balance of the product, using samples from previous production runs. Samples are then taken from current runs and sensitometric curves are prepared for the samples. If the current product deviates beyond a tolerance range for color speed balance, the level of at least one filter dye is changed. Further samples incorporating this change are then taken and their color speed balance measured to determine the effectiveness of the dye change. This process is then repeated until the desired effect is achieved.
Thus, in the art of manufacturing photographic films and papers, a need has existed for a method and an apparatus for determining and displaying how a photographic product's color density responses compare to established quality indicator parameters or standards and for predicting and displaying how changes in control variables for the product or its production process will bring the product within desired limits. Such a method and apparatus would enable the manufacturer to adapt relatively quickly to changes in the product during manufacture, which changes are caused by unexpected variations in the constituents of the product, conscious changes in the design of the product, variations in the production conditions and the like.

Method for assessing and controlling the sensitometric characteristics of photographic products


A method and apparatus for managing task context are provided. Upon initialization, a protocol engine provides context resources available for processing tasks to a task issuer. Based on available context resources, the task issuer creates and manages a free list of available task context indices and assigns an index to a task prior to storing task context in a context memory accessible to both the task issuer and the protocol engine and issuing the task to the protocol engine.

Storage communication protocols such as the Serial Attached Small Computer Systems Interface (SAS) and Fibre Channel Arbitrated Loop (FCAL) provide a connection-oriented service with acknowledged delivery. A connection is established between devices prior to transfer of data between them. In the event that the connection is terminated, the connection must be re-established prior to resuming transfer of the data. The process for establishing the connection may require an exchange of frames between the devices.
There may be many simultaneous active connections requiring the management of thousands of task requests that are typically issued by a device driver in the operating system to a storage controller. A task represents the work associated with a command or group of linked commands. A context associated with the task is typically stored in a data structure and includes information required to process the task. The information may include the type of command to be issued and an identifier identifying the storage device to which the command is to be issued. One example of a task may be a command to write a file to a disk drive and the parameters of the command include a number of sectors to write on the disk drive.
As the issued task requests may be queued prior to being processed, each task request is typically assigned both an Input/Output (I/O) tag and a context identifier (ID) which are used to track the tasks. The context ID is typically assigned by hardware in the storage controller and used by the hardware to associate tasks with specific resources in the storage controller. The I/O tag is typically assigned by firmware in the storage controller and used by the firmware to identify the task. The context ID may be unrelated to the I/O tag.
A large task request queue is required in the storage controller to store the task requests and their associated context for all task requests issued to the storage controller. Furthermore, a request to abort or suspend a task issued by firmware in the storage controller requires finding a context ID associated with the I/O tag prior to processing the request. A list of tasks in process must be searched in order to find one with a matching I/O tag. This requires additional logic which is dependent on the number of tasks in progress.
An alternative to searching through a list of tasks is to have the hardware in the storage controller return the context ID assigned to each task when it accepts a task from firmware. The returned context ID is stored in a mapping table with the associated I/O tag. Instead of having to search through the entire list, the mapping table can be searched for a matching context ID. However, the return of a context ID for each task increases the number of accesses to the hardware that are performed for each task. Instead of two accesses, one to issue the request and the second to accept completion status, a third access is required by firmware to retrieve the context ID and store it in the mapping table with the I/O tag. Furthermore, although the context ID is rarely used this third access is required for each task in case the context ID is needed by the firmware to abort or suspend a task.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments of the claimed subject matter, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly, and be defined only as set forth in the accompanying claims.

Task context direct indexing in a protocol engine


The growth rate of meat-producing animals as well as the yield and quality of the meat obtained therefrom is improved by administering to the animal prior to its sexual maturation an effective amount of a female gonadal steroidal compound; namely, an estrogen or progestagen compound and preferably a mixture thereof, sufficient to delay development of the gonadal function of the animal, e.g., spermatogenesis. Such administration is terminated sufficiently prior to slaughter of the animal that the administered steroidal compound has been substantially completely removed from the animal's system which before slaughter exhibits levels of the corresponding natural hormones therein substantially within normal limits. In mammals, administration is preferably by injection, but in fish, shellfish and poultry, the active steroidal compound is incorporated at low levels in the usual feed therefor. In mammals, the treatment is preferably applied to uncastrated males but can be extended to females and castrated males if desired; while in fish, shellfish and poultry administration is without regard to sex. The ratio of lean meat to fat is increased significantly by the treatment and in male mammals aggressiveness and odor development with consequential tainting of the meat is suppressed until slaughter.

It has long been desired to increase the rate of growth in meat-producing animals as well as to enhance the quality of the meat derived therefrom, especially as regards the proportion of lean to fat in such meat. Progress has, of course, been made to this end by the hybridization of various meat producing animals and in formulating improved feed compositions with a view to achieving an increase in the rate of growth of the animal and the efficiency of the conversion of its feed, i.e., the ratio of unit weight of meat produced per unit quantity of feed consumed, but little hope appears to exist for further major progress along these lines.
Another long-recognized approach adopted for male meat-producing mammals is castration of animals usually at an early stage in their development for the purpose of achieving a kind of feminization of the male animal while simultaneously eliminating its normal aggressive behavior and sexual activity. More recently, castration has been combined with hormone administration typically accomplished by a continuous release hormonal implant inserted, for instance, in the ear of the castrated animal at an age typically of 2-3 months. The the quantity of the hormone and the rate of its release from the implant, as determined by the composition of the implant, are so designed as to achieve a gradual and continual release of the hormone into the animal's system and so correlated with the rate of metabolism of the hormone in the animal's system that the quantity of hormone remaining in the ultimate meat obtained after slaughter was sufficiently small as to satisfy applicable government standards. While castration alone or combined with a hormone implant has some beneficial consequences on the ultimate meat production in terms of increased weight production and thus better feed efficiency, much of the improvement is in the form of increased fat, e.g., a higher ratio of fat to lean which, of course, offsets the overall improvement by reduced meat quality.
Considerable research has been done by the present applicants, their associates, and others in the field of hormones in order to acquire a better understanding of the enormously complex changes that are involved in hormone secretion in animals and the effects of such secretion in various animal species. Extensive studies have been applied to such animals such as fish, chicken, pig and ruminants such as deer. Thus, it has been described how the adenohypophyseal cells of teleost fish, chicken, rats and pigs respond to gonadal steroids administered during embryogenesis, the neonatal or "critical" period, the adult stage, and during old age. This research was done by V. R. Pantic in "Synthesis and Release of Adenohypophyseal Hormones", Plenum Press, N. Y. 1980 (M. Jutisz and K. W. McKerns, eds.) pp. 335-362. Gonadotropic cells that secrete FSH and LH were found to be suppressed, while prolactin and growth stimulating cells were increased. The effects were most pronounced during embryogenesis and the neonatal critical period. These studies were continued, with the emphasis on prolactin target cells, by V. R. Pantic, in "Regulation of Target Cell Responsiveness", Vol 2, Plenum Press, N.Y. 1984 (K. W. McKerns, A. Aakvaag and V. Hansson, eds.) pp 283-295. Further, it has been shown by F. C. Bancroft, P. R. Dobner and Li-Yuan Yu, in "Synthesis and Release of Adenohypophyseal Hormones", Plenum Press, N.Y. 1980 (M. Jutisz and K. W. McKerns, eds.) pp. 311-333;that glucocorticoids induce pregrowth hormone messenger RNA. A description has been provided how prolactin, growth hormone, and chorionic somatomammotropin are derived from a common evolutionary ancester protein. All are lactogenic and growth promoting: W. L. Miller and S. W. Mellon, in "Regulation of Gene Expression, Plenum Press, N.Y. 1983 (K. W. McKerns, ed.) pp. 177-202. During evolution the genes for these hormones migrated to separate cell types and are under complex regulatory processes.
The complexity of hormonal effects and the difficulty of predicting the consequences of the same is illustrated by the different and even opposite effects that are often obtained according to the amount and the duration of the administration of a given hormone as well as the period of such administration in the development of the animal. For example, a low-level constant administration may continually suppress a particular function; a single higher does may initially suppress that function, followed by a rebound increase. The suppression of adrenal cortex secretion by estrogen, followed by a marked rebound increase in adrenal glucocorticoid secretion has been described by K. W. McKerns in "The Regulation of Adrenal Function by Estrogens and Other Hormones", Biochemica Et Biophysica Acta, 71 (1963) 710-718.
From the information obtained during studies such as the above as well as subsequent unpublished research, it has been discovered, quite remarkably, that the administration of a female gonadal steroidal hormone to meat producing animals if applied to the animal before its sexual maturation, and preferably quite early, especially during its neonatal period, a surprising and entirely unexpected selective response is induced by which the sexual maturation of the animal, e.g., achievement of the gonadal function such as spermatogenesis in males and development of secondary sex characteristics is suppressed or retarded while the growth function and anabolic effect of the animal is enhanced and made more efficient. Those knowledgeable in endocrinology have traditionally believed that sexual maturation, e.g., spermatogenesis in the male, the development of secondary sexual characteristics, including the development of the seminal glandular system of the animal, and release of androgen and growth hormone prolactin complex to achieve a growthanabolic effect in male animals occurred together in the natural maturation of the animal. Thus, castration would obviously prevent spermatogenesis and the development of secondary sexual characteristics but with a consequential reduction in the release of androgen and its anabolic effect and the growth hormone-prolactin effect so that growth production was channeled more toward fat rather than muscle or lean meat.
In the practice of the present invention, an unexpected and surprisingly selective or differential response has been found, by which spermatogensis and secondary sexual development are temporarily suppressed or blocked while simultaneously androgen and growth hormone-prolactin production, as manifested, for example, by the level of the male gonadal hormone testosterone is not only not suppressed but remains at least comparable to, if not higher than, that taking place in similar untreated animals. As a consequence, the animal can be brought to its normal slaughter weight at a time significantly earlier than is required for untreated or intact animals or castrated animals. The conversion of the feed by the animal during the growth period up to slaughter, which is its most rapid growth period, takes place at a significantly more efficient rate, as measured in terms of unit weight of meat derived per unit weight of feed consumed. Further, the proportion of fat is reduced so that a leaner meat product having a higher ratio of lean to fat is obtained giving a significantly higher meat quality. The characteristics of the meat in other respects such as flavor, tenderness, texture and so on do not appear to be adversely affected by the practice of the present method and remain at least as acceptable as, if not better than, those of meat obtained from untreated animals, including castrates.
Additional benefits have also been observed in some species notably the pig. Sexual maturation in the male pig occurs, on the average, at around five months and is manifested by aggressive behavior and sexual activity such as fighting with other males and attempted mountings. As the secondary sexual characteristics become fully developed, the seminal system becomes operative resulting in the strong odor characteristic of boars and this strongly oderiferous seminal fluid permeates the tissue of the animal causing its meat to be tainted for most human consumption. Male pigs treated according to the present invention do not exhibit such aggressive behavior and are free from the obnoxious scent and meat flavor of untreated male pigs.
The reality of the improvements described above has been theoretically confirmed by histological testing of the treated animals compared with untreated animals. Thus, the present method has been shown to lead to induction, proliferation and increased gene expression of growth and prolactin cells in the pituitary that secrete growth hormone, growth factors and prolactin hormone. Prolactin has both a growth stimulating effect and a gonad suppressing effect. Pituitary gonadotrophs that secrete folicle stimulating hormones (FHS) and luteinizing hormones (LH) appear to be suppressed in number and function. The pro-opioidcorticotropin cells appear to be increased. Incereased endorphins (and other opioid compounds) from these cells may have a sedative-tranquilizing effect on the animals. Increased corticotropin (ACTH) enlarges the vascular and reticular zone of the adrenal cortex and increases glucocorticoid and androgen production.
More specifically, taking the pig as an example, it was observed histologically by the light microscope and the electron microscope that growth hormone and prolactin cell types in the pig pituitary were increased, as were cells that secrete pro-ACTH-endorphin. On the other hand, gonadotropin cells that secrete FSH and LH were decreased.

Method for promoting growth and improved meat quality in meat producing animals with female steroidal hormones

International Foundation for Biochemical Endocrinology


A fingerprint sensor module includes a lens, a filter, a first reflector, an image capturing module for capturing a first fingerprint image and a second fingerprint image, and at least one first light source for providing the needed light source at the time of the image capturing module capturing the fingerprint image. A top surface and a bottom surface of the lens are planes. The lens defines at least one first area and a second area. The filter is disposed under the lens. The filter is corresponding to the first area of the lens for reflecting the first fingerprint image corresponding to the first area. The first reflector is disposed under the lens. The first reflector is corresponding to the second area of the lens for reflecting the second fingerprint image corresponding to the second area.

1. Field of the Invention
The present invention generally relates to a fingerprint sensor module, and more particularly to an optical fingerprint sensor module.
2. The Related Art
Currently, optical fingerprint sensor modules and capacitive fingerprint sensor modules are mainstream products of fingerprint sensor modules on the market. In general, the high-density capacitive fingerprint sensor module is integrated into a chip. When a fingerprint is pressed downward on a surface of the chip, the capacitive fingerprint sensor module senses a fingerprint image through different quantities of electric charge of fingerprint peaks and troughs. The advantage of the capacitive fingerprint sensor module is thinness. But the capacitive fingerprint sensor module has a higher cost, a lower sensing accuracy and a lower durability.
The optical fingerprint sensor module captures the fingerprint image by the principle of imaging. Comparing with the capacitive fingerprint sensor module, the optical fingerprint sensor module has the advantages of higher identification, lower price and better durability. But the imaging system needs to keep a distance from the lens to the sensor to form the fingerprint image clearly. The imaging light path makes a size of the optical fingerprint sensor module become larger and thicker.
Due to a current electronic product being developed towards the trend of thinness, factories wish to manufacture the optical fingerprint sensor modules of which each has a thinner structure one after another for being appropriate to internal structures of the thinner electronic products.
The current optical fingerprint sensor module shortens the straight distance between the sensor and the lens to reduce the thickness of the optical fingerprint sensor module by an imaging light path refracted by a prism. For example, U.S. Pat. No. 8,405,757 discloses a conventional embodiment where a component pressed by the fingerprint is the prism. Through a refraction characteristic of a light the fingerprint image is formed by a prism. It makes the fingerprint image be formed through a total internal reflection light path by the prism to the lens.
In other conventional technology, in order to satisfy the thinness need, the difference is that some is commenced from a structure of the special lens, or a variety of lenses with complex structures are designed to reduce the thickness of the optical fingerprint sensor module for increasing a possibility of being applied in a cell phone or a tablet computer.
However, a structure of the refraction path of the current optical fingerprint sensor module is complex that makes the cost of the fingerprint sensor module is higher and the thickness of the optical fingerprint sensor module has no way of being less than 6.5 mm. Thus, it's difficult to manufacture the current optical fingerprint sensor module in mass production.
In view of this, it's essential to provide an optical fingerprint sensor module with a simple structure, a lower cost and a thickness of being less than 6.5 mm.


Apparatus and methods of measuring three-dimensional position information of a onto a surface of an object including two sources of radiation separated by a distance, each source having a spectral distribution, and being coherent with respect to the other of the sources, a control system moving each of the sources relative to the other of the sources, and a detector positioned to receive radiation scattered from the point on the surface of the object. In another embodiment, the two sources of radiation include, an initial source of a beam of radiation having a spectral width, a beam separator in optical communication with the initial source of a beam of radiation generating a first optical beam and a second optical beam, and an imaging system optically connected to the beam separator.

Dimensional metrology, the measurement of the size and shape of objects, is very important in today's manufacturing environment in which machines perform much of the fabrication and assembly of complex objects composed of many subassemblies. The shape and size of each component in a complex assembly, such as an automobile, must be held to close tolerances to ensure that the components fit together properly.
Ideally such measurements of shape and size are accomplished without physical contact in order to save time in making the measurement. Many non-contact measurement methods make use of available machine vision systems. The measurement of surface contour information is an especially difficult problem in machine vision systems since depth information is often lost or is difficult to interpret. To compensate for the loss of depth information and the difficulty in interpreting the information which is available, many machine vision systems utilize light to create moiré patterns on the surface of the object in order to obtain contour information. One disadvantage of the moiré technique is its inflexibility with respect to objects of different sizes. Objects of different sizes may require new corresponding physical setups. Due to this disadvantage, it is difficult to use a moiré technique for large-scale objects. Another disadvantage of a moiré technique is that the resolution obtained using the technique may not be high enough for many applications
Interferometric methods have also been used when detailed measurements of the surface are needed. Although interferometric systems provide surface contour information, they are sensitive to vibrations in both the object being measured and the source of illumination being used.
What is needed is a technique which avoids these problems by resolving fringe order ambiguities, mitigating degradation due to speckle effects and attaining high resolution.

Apparatus and methods for surface contour measurement


A method for fabricating a fastener and washer assembly wherein the washer is permanently retained on the fastener by an annular raised portion on the shank of the fastener. The annular raised portion and the inner diameter of the washer are mutually formed so as to promote elastic deformation of both the raised portion and the washer when the washer is forced over the raised portion to be retained on the fastener. The method allows the fastener and the washer to be fully fabricated and processed prior to assembly, including such desirable steps as heat treating and plating of both the fastener and the washer. The annular raised portion is formed by a pair of converging annular surfaces which define a predetermined diameter. The washer has an inner diameter surface having a pair of chamfered edges. The washer is assembled onto the shank of the fastener by forcing the chamfered edge of the washer against and past the annular raised portion. the inner diameter is sized relative to the diameter of the annular raised portion such that it is elastically, and not plastically, expanded while the annular raised portion is elastically compressed as the washer is forced over the annular raised portion. Thereafter, both the washer and the annular raised portion elastically revert back to their respective diameters. The washer is permanently retained on the fastener by the raised portion to form the fastener and washer assembly.

1. Field of the Invention
The present invention generally relates to fastener and washer assemblies used as securing or fastening devices. More specifically, this invention relates to a fastener and washer assembly in which the washer is permanently retained on the shank of the bolt by a raised periphery, wherein the raised periphery is formed on the shank of the fastener prior to installing the washer and wherein the washer is provided with a lead chamfer on its internal diameter which enables the washer to be elastically forced over the raised periphery of the fastener so as to be permanently retained thereby.
2. Description of the Prior Art
Pre-assembled fastener and washer assemblies have gained wide acceptance in manufacturing because of the convenience and efficiency they offer, providing the manufacturer with savings in both assembly time and costs. The fastener can be either a screw or a bolt which is intended to receive a nut. Fastener and washer assemblies are commonly available in many sizes to accommodate applications ranging from electronics to automobile assemblies. Such applications generally demand a clamping capability which can be maintained in an environment which includes vibration and temperature variations that tend to fatigue or otherwise decrease the fastener's ability to sustain the desired clamping load. Accordingly, the fastener and washer must each possess specific material characteristics suitable for the particular application and its environment. However, the material characteristics of the fastener and washer, such as strength, stiffness, and heat and surface treatments, are ultimately dependent upon the method used to manufacture the assembly. Consequently, the processing techniques used to form the fastener and washer and assemble them together can be critical.
Where material characteristics, particularly surface and heat treatments, of the fastener and washer are not critical, the washer can be assembled to the fastener prior to the final processing steps of the fastener. Such an approach is taught in U.S. Pat. Nos. 2,303,224 to Olson; 2,792,578 to Autio; 2,914,780 to Poupitch; 3,862,458 to Stanaitis; and 3,837,212 to Gutshall. Olson teaches assembling the washer to the fastener, and thereafter retaining the washer on the fastener by forming a raised knurled rib on the perimeter of the fastener's shank to trap the washer between the fastener head and the knurled rib. Similarly, Autio teaches forming intermittent protuberances on the perimeter of the fastener's shank after the washer has been assembled to the fastener, while both Stanaitis and Gutshall form a flange on the fastener's shank for retaining a previously assembled washer.
In contrast, Poupitch teaches actually forming the fastener after the washer is in place such that the washer is retained against the fastener head by a protrusion on the shank's perimeter. Further variations of this approach are illustrated by U.S. Pat. Nos. 1,262,975 to Pierce and 1,868,415 to Gundersen et al. Pierce actually welds the shank of the fastener to the fastener head in a manner which rigidly secures a washer to the fastener. Annular reliefs formed along the inner diameter of the washer receive molten metal from the shank and fastener head during welding to positively retain the washer. Gundersen et al initially forms the washer as an integral part of the fastener, and thereafter shears the washer from the shank of the fastener in a manner that produces a tapered inner diameter to the washer. The threads of the fastener are formed so as to be greater in diameter than the inner diameter of the washer to positively retain the washer to the fastener.
A disadvantage to all of the above approaches is that the material characteristics of the fastener and washer are severely limited in that the final processing steps occur after the washer is secured to the fastener. In particular, any heat treating or surface treatments desired after the final forming steps must be carried out on both the fastener and washer, whether to do so is desirable or not. The alternative is to forego any subsequent heat treating or surface treatment. However, this is highly undesirable under many circumstances, particularly where improved material characteristics would allow the use of smaller fasteners which provide for substantial weight and space savings. In addition, surface and heat treatments are desirable where the environment is particularly corrosive or is subject to temperature extremes.
Accordingly, forming the fastener and washer during entirely different steps and from different materials allows greater versatility in the material qualities and uses of the fastener and washer assembly. For instance, the fastener can be formed to have optimal strength while forming the washer from a more resilient material. Further, the fastener and washer can separately undergo heat and surface treatments particularly suited for the materials used and the intended environment.
One solution for achieving this advantage is to retain the washer on the fastener with a third member, such as a collar. This type of approach is illustrated in U.S. Pat. No. 3,687,184 to Wagner. Wagner teaches the use of a retainer member having an annular shoulder which is slightly greater than the inner diameter of the washer. The washer is first assembled to the retainer member, being forced over the annular shoulder so as to retain the washer directly to the retainer member. The retainer member is then assembled to the fastener, being retained on the fastener with a slight interference between the inner diameter of the retainer member and the fastener threads. However, a clear disadvantage with the teachings of Wagner is the need for an additional member, incurring additional part costs and assembly time. Another possible disadvantage is the potential adverse effects on the clamping capability of the fastener and washer assembly.
As an alternative, U.S. Pat. No. 2,283,494 to Erdman teaches the preforming of an annular shoulder on the shank of a fastener prior to assembling the washer. The washer is described as being forced over the annular shoulder so as to be permanently retained thereby. In practice, this approach requires that the tolerances between the diameter of the washer and the shoulder must be closely held to allow the washer to be forced over the shoulder without significantly deforming the washer. Such tight tolerances are undesirable, as they are expensive and difficult to maintain in a mass-produced item such as a fastener and washer. It is a likely tendency that the pressing procedure necessary to force the washer onto the fastener requires a substantial force, resulting in the inner diameter of the washer being deformed. Such a result is even more likely where the fastener or the washer has been hardened through a heat treatment or surface treatment process. A supplemental approach to diminishing the likelihood of permanent deformation to the washer is to limit the washer material to a spring steel, and further to limit the thickness of the washer to enhance its resiliency. However, any attempt to facilitate assembly by altering the material characteristics severely limits the choice in materials, limiting the types of applications for which the fastener and washer assembly are suitable.
From the above discussion, it can be readily appreciated that the prior art does not disclose a fastener and washer assembly which possesses the advantages of allowing the fastener and washer to be independently processed prior to assembling, while also facilitating assembly such that additional members and undersirably tight tolerances are avoided. Nor does the prior art teach or suggest such a fastener and washer assembly which avoids the requirement of excessive assembly forces which have the tendency to damage and otherwise deform the members of the assembly.
Accordingly, what is needed is a method of producing a fastener and washer assembly which allows the fastener and washer to be formed and processed independent of each other, yet provides that the fastener and washer are formed such that they can be readily assembled together inexpensively even after such processing as heat and surface treatments. As an advantageous result, the fastener and washer can be manufactured and assembled with conventional tolerances, which facilitate mass production.

Method of making a bolt and washer assembly


Driving system for a an industrial truck with a combustion engine, a two-branch gear transmission whose first shaft is coupled to the combustion engine, whose second shaft is coupled to a change-over transmission, whose outlet acts on the driven wheels of the industrial truck via a collecting transmission, an electric transmission of which a first electric machine cooperates therewith, with respect to the torque, using the two-branch gear transmission, and a second electric machine is coupled via at least one collecting transmission to the driven wheels, the two-branch gear transmission producing a constant torque ratio between the first electric machine and at least the first and second shaft and an electrical circuit arrangement electrically coupling the electric machines and being connected to an electric accumulator,    two mechanical hydraulic converters of which one is coupled to the first or second shaft of the two-branch gear transmission and the second to the electric transmission, and    devices for the absorption of hydraulic energy which are associated with each mechanical hydraulic converter.

Combustion engine driven industrial trucks require a transmission in order to provide the desired torque at the desired speed. It is desirable that the industrial truck can be driven forwards and backwards at the same high maximum speed.
In motor vehicles, it is known to use a clutch and a hydrokinetic converter in combination with single-step or multi-step transmissions. However, such a system has only limited suitability for industrial trucks, as at low driving speeds it has low efficiency. Furthermore, a clutch function is required for the independent operation of the lifting function of the industrial truck.
The disadvantages of a hydrodynamic transmission system do not occur with a hydrostatic drive train. It uses a continuously variable conversion range and allows easy reversing. However, the poor efficiency at faster driving speeds opposes the relatively high efficiency of driving at slower speeds. As a result of the multiple hydraulic-mechanical conversion of the total driving power, the efficiency of a mechanical gear changing mechanism is not achieved. A further disadvantage is the relatively high construction cost, due to the high hydraulic pressures up to 400 bar and the susceptibility of the system to defects, in particular with regard to leakage.
Finally, it is also known in the industrial truck field to carry out the transmission of forces by means of an electric transmission. In an electric transmission, all the energy generated by the combustion engine is converted into electrical energy by means of a generator. The electrical energy is reconverted into mechanical energy by means of an electric motor. Within predefined limits, drive controls for electric machines allow any gear ratios between the generator and electric motor. Hence, such a system has the advantage of particularly good controllability. The low efficiencies caused by the high losses in the control mechanisms and electric machines are, however, disadvantageous.
Existing driving solutions in combustion engine operated industrial trucks generally involve considerable energy losses in certain operating situations. Furthermore, they are not capable of returning energy to an accumulator when braking or lowering loads. Emissionless operation is also impossible which almost excludes the use of such industrial trucks in enclosed spaces. A further disadvantage of the former driving systems lies in the fact that the components have to be designed for peak loads whilst the mean loading of the components is clearly below such values. Thus a higher construction cost is incurred which is not required for the mean value.
A continuously variable, hydrostatic-mechanical power shift transmission for industrial trucks is known from DE 138 15 780 which is intended to achieve continuously variable hydrostatic starting or reversing with reduced construction cost. The known transmission has a plurality of clutches and gearwheel switch stages. Emissionless operation of the driving system is not possible and the kinetic energy when braking and lowering loads cannot be recovered. Purely hydrostatic starting leads to poor transmission efficiency until switching to power branching transmission. Furthermore, reversing at maximum speed is not possible.
A hydrostatic-mechanical drive for industrial trucks is known from DE 197 47 459 which is intended to utilise the advantages of a hydrostatic drive combined with a mechanical drive, in that the total efficiency of the transmission is increased via the mechanical branch. Such a driving system can be designed such that it can be driven from a standstill to maximum speed, in a preferred direction of travel, with good transmission efficiency. In the other direction of travel the efficiency is low in the maximum speed range. Emissionless operation of the driving system is not possible and it is also not possible to recover braking- and lowering load energy.
A two-branch gear transmission and an operating method is known from DE 198 03 160 which is intended to improve the efficiency behaviour and the service life of the driving system. In addition, a rotary brake which is controllable depending on the driving state of the vehicle, is intended to stop a shaft temporarily or permanently when a shaft exceeds a maximum speed. Emissionless operation of the driving system, which is not designed for industrial trucks, is not possible and it is also not possible to recover braking- or load energy. Furthermore, reversing at maximum speed also cannot be achieved.
Combustion engine driven driving systems for industrial trucks are known from DE 199 55 311, DE 199 55 312 and DE 199 55 313, in which a combustion engine and at least one electric machine generate the drive energy. The known driving systems contain at least one collecting transmission for combining the energy of the combustion engine and the electric machine. It is therefore intended that the performance is improved as a whole, with continuously variable good controllability and an increase in total efficiency. The known driving systems require mechanical brakes in the driving state, in order to achieve the required minimum braking even at maximum speed and without oversized electric machines. The combustion engines in the known driving systems are rigidly connected to the subordinate transmission system so that during emissionless electrical operation, the combustion engine idles and is subject to loss.
The object of the invention is to produce a combustion engine driven, two-branched driving system for industrial trucks which can be operated without emissions, allows recovery of braking- and lowering load energy and, in particular, can dispense with mechanical brakes in the driving state.


The invention relates to substituted aryl and heteroaryl (R)-Chiral Halogenated 1-Substitutedamino-(n+1)-Alkanol compounds useful as inhibitors of cholesteryl ester transfer protein (CETP; plasma lipid transfer protein-I) and compounds, compositions and methods for treating atherosclerosis and other coronary artery diseases. Novel high yield, stereoselective processes for the preparation of the chiral substituted alkanol compounds from chiral and achiral intermediates are described.

Numerous studies have demonstrated that a low plasma concentration of high density lipoprotein (HDL) cholesterol is a powerful risk factor for the development of atherosclerosis (Barter and Rye, Atherosclerosis, 121, 1–12 (1996)). HDL is one of the major classes of lipoproteins that function in the transport of lipids through the blood. The major lipids found associated with HDL include cholesterol, cholesteryl ester, triglycerides, phospholipids and fatty acids. The other classes of lipoproteins found in the blood are low density lipoprotein (LDL) and very low density lipoprotein (VLDL). Since low levels of HDL cholesterol increase the risk of atherosclerosis, methods for elevating plasma HDL cholesterol would be therapeutically beneficial for the treatment of atherosclerosis and other diseases associated with accumulation of lipid in the blood vessels. These diseases include, but are not limited to, coronary heart disease, peripheral vascular disease, and stroke.
Atherosclerosis underlies most coronary artery disease (CAD), a major cause of morbidity and mortality in modem society. High LDL cholesterol (above 180 mg/dl) and low HDL cholesterol (below 35 mg/dl) have been shown to be important contributors to the development of atherosclerosis. Other diseases, such as peripheral vascular disease, stroke, and hypercholesterolaemia are negatively affected by adverse HDL/LDL ratios. Inhibition of CETP by the subject compounds is shown to effectively modify plasma HDL/LDL ratios, and to check the progress and/or formation of these diseases.
CETP is a plasma protein that facilitates the movement of cholesteryl esters and triglycerides between the various lipoproteins in the blood (Tall, J. Lipid Res., 34, 1255–74 (1993)). The movement of cholesteryl ester from HDL to LDL by CETP has the effect of lowering HDL cholesterol. It therefore follows that inhibition of CETP should lead to elevation of plasma HDL cholesterol and lowering of plasma LDL cholesterol, thereby providing a therapeutically beneficial plasma lipid profile (McCarthy, Medicinal Res. Revs., 13, 139–59 (1993); Sitori, Pharmac. Ther., 67,443–47 (1995)). This exact phenomenon was first demonstrated by Swenson et al., (J. Biol. Chem., 264, 14318 (1989)) with the use of a monoclonal antibody that specifically inhibited CETP. In rabbits, the antibody caused an elevation of the plasma HDL cholesterol and a decrease in LDL cholesterol. Son et al. (Biochim. Biophys. Acta 795, 743–480 (1984)), Morton et al. (J. Lipid Res. 35, 836–847 (1994)) and Tollefson et al. (Am. J. Physiol., 255, (Endocrinol. Metab. 18, E894–E902 (1988))) describe proteins from human plasma that inhibit CETP. U.S. Pat. No. 5,519,001, issued to Kushwaha et al., describes a 36 amino acid peptide derived from baboon apo C-1 that inhibits CETP activity. Cho et al. (Biochim. Biophys. Acta 1391, 133–144 (1998)) describe a peptide from hog plasma that inhibits human CETP. Bonin et al. (J. Peptide Res., 51, 216–225 (1998)) disclose a decapeptide inhibitor of CETP. A depsipeptide fungal metabolite is disclosed as a CETP inhibitor by Hedge et al. in Bioorg. Med. Chem. Lett., 8, 1277–80 (1998).
There have been several reports of non-peptidic compounds that act as CETP inhibitors. Barrett et al. (J. Am. Chem. Soc., 188, 7863–63 (1996)) and Kuo et al. (J. Am. Chem. Soc., 117, 10629–34 (1995)) describe cyclopropane-containing CETP inhibitors. Pietzonka et al. (Bioorg. Med. Chem. Lett, 6, 1951–54 (1996)) describe phosphonate-containing analogs of cholesteryl ester as CETP inhibitors. Coval et al. (Bioorg. Med. Chem. Lett., 5, 605–610 (1995)) describe Wiedendiol-A and -B, and related sesquiterpene compounds as CETP inhibitors. Japanese Patent Application No. 10287662-A describes polycyclic, non-amine containing, polyhydroxylic natural compounds possessing CETP inhibition properties. Lee et al. (J. Antibiotics, 49, 693–96 (1996)) describe CETP inhibitors derived from an insect fungus. Busch et al. (Lipids, 25, 216–220, (1990)) describe cholesteryl acetyl bromide as a CETP inhibitor. Morton and Zilversmit (J. Lipid Res., 35, 836–47 (1982)) describe that p-chloromercuriphenyl sulfonate, p-hydroxymercuribenzoate and ethyl mercurithiosalicylate inhibit CETP. Connolly et al. (Biochem. Biophys. Res. Comm. 223, 42–47 (1996)) describe other cysteine modification reagents as CETP inhibitors. Xia et al. describe 1,3,5-triazines as CETP inhibitors (Bioorg. Med. Chem. Lett., 6, 919–22 (1996)). Bisgaier et al. (Lipids, 29, 811–8 (1994)) describe 4-phenyl-5-tridecyl-4H-1,2,4-triazole-thiol as a CETP inhibitor. Oomura et al. disclose non-peptidic tetracyclic and hexacyclic phenols as CETP inhibitors in Japanese Patent Application No. 10287662.
Some substituted heteroalkylamine compounds are known. In European Patent Application No. 796846, Schmidt et al. describe 2-aryl-substituted pyridines as cholesteryl ester transfer protein inhibitors useful as cardiovascular agents. One substitutent at C3 of the pyridine ring can be an hydroxyalkyl group. In European Patent Application No. 801060, Dow and Wright describe heterocyclic derivatives substituted with an aldehyde addition product of an alkylamine to afford 1-hydroxy-1-amines. These are reported to be β3-adrenergic receptor agonists useful for treating diabetes and other disorders. In Great Britain Patent Application No. 2305665, Fisher et al. disclose 3-agonist secondary amino alcohol substituted pyridine derivatives useful for treating several disorders including cholesterol levels and artherosclerotic diseases. In European Patent Application No. 818448, Schmidt et al. describe tetrahydroquinoline derivatives as cholesteryl ester transfer protein inhibitors. European Patent Application No. 818197, Schmek et al. describe pyridines with fused heterocycles as cholesteryl ester transfer protein inhibitors. Brandes et al. in German Patent Application No. 19627430 describe bicyclic condensed pyridine derivatives as cholesteryl ester transfer protein inhibitors. In WO Patent Application No. 09839299, Muller-Gliemann et al. describe quinoline derivatives as cholesteryl ester transfer protein inhibitors. U.S. Pat. No. 2,700,686, issued to Dickey and Towne, describes N-(2-haloalkyl-2-hydroxyethyl)amines in which the amine is further substituted with either 1 to 2 aliphatic groups or one aromatic group and one aliphatic group. U.S. Pat. No. 2,700,686 further describes a process to prepare the N-(2-haloalkyl-2-hydroxyethyl)amines by reacting halogenated-1,2-epoxyalkanes with the corresponding aliphatic amines and N-alkylanilines and their use as dye intermediates.

This patent is subject to a terminal disclaimer.

(R)-chiral halogenated substituted fused heterocyclic amino compounds useful for inhibiting cholesterol ester transfer protein activity


A temperature control method for use in a fusing device of image forming apparatus having a fusing roller and a heater heating the fusing roller, including: sensing a surface temperature T of the fusing roller at one of when the image forming apparatus is turned on, when the image forming apparatus begins a normal operation from a power saving operation, and when a cover of the image forming apparatus is closed after being opened; comparing the sensed surface temperature T of the fusing roller with a set temperature; driving the heater until the surface temperature T reaches a first target temperature Tt1 when the sensed surface temperature T is below the set temperature; and driving the heater until the surface temperature T reaches a second target temperature Tt2 when the sensed surface temperature T is over the set temperature.

1. Field of the Invention
The present invention relates to fusing devices of image forming apparatus such as a laser beam printer, a multi-function machine, a photocopier, and the like, and more particularly, to a method of temperature control in a fusing device of an image forming apparatus by optimizing a power supply to a heater that heats a fusing roller of the fusing device and minimizing fluctuation in surface temperature of the fusing roller.
2. Description of the Related Art
Generally, an image forming apparatus such as a photocopier, a laser beam printer and the like, prints a desired image on a recording medium such as, a sheet of printing paper, by a series of image forming processes. The image forming processes include electrically charging a surface of a photosensitive drum by rotating an electrostatic charging roller disposed adjacent to the photosensitive drum, exposing the surface of the photosensitive drum to a laser beam projected from a laser scanning unit (LSU) to form an electrostatic latent image on the surface of the photosensitive drum, developing the electrostatic latent image formed on the surface of the photosensitive drum to a toner image of a powdery state (i.e. a powdery visible image) by supplying a toner to the surface of the photosensitive drum, transferring the toner image formed on the surface of the photosensitive drum onto the sheet of printing paper by passing the sheet between the photosensitive drum and a transfer roller which are in contact with each other under a pressure, by supplying a transfer voltage to the transfer roller and the photosensitive drum, and fusing the powdery toner image onto the sheet of printing paper by heating the sheet of printing paper with the toner image transferred thereon through a fusing device including a fusing roller.
Generally, in the process of fusing the toner image, a halogen lamp is employed as a heating source of the fusing device. The halogen lamp is disposed inside the fusing roller and/or a fusing backup roller to radiantly heat a surface of the fusing roller and/or the fusing backup roller to a temperature.
FIG. 1 schematically shows a conventional fusing device 10 of a conventional electrophotographic image forming apparatus.
The fusing device 10 includes a cylinder-shaped fusing roller 11 that has a non-stick coating layer of, for example, TEFLON® on a surface thereon, and a halogen lamp 12 disposed in an inner center thereof. The arrangement of the fusing roller 11 and the halogen lamp 12 is also shown in FIG. 2. The halogen lamp 12 generates heat inside of the fusing roller 11, and the fusing roller 11 is thereby heated by a radiant heat from the halogen lamp 12.
Returning to FIG. 1, disposed under the fusing roller 11 is a fusing backup roller 13. As shown in FIG. 3, the fusing backup roller 13 is resiliently supported by a spring 13a, so as to press a sheet of printing paper 14 passing between the fusing roller 11 and the fusing-backup roller 13, toward the fusing roller 11 with a pressure.
Accordingly, while the sheet of printing paper 14 is passing between the fusing roller 11 and the fusing backup roller 13, a toner image 14a formed on the sheet of printing paper 14 in the powdery state is subjected to a pressure and a heat. As a result, the toner image 14a is fused and fixed onto the sheet of printing paper 14 by the pressure and the heat imposed thereto through the fusing roller 11 and the fusing-backup roller 13.
Returning to FIG. 1, installed at a side of the fusing roller 11 are a thermistor 15, a thermostat 16 and a power switching part 19 such as a thyristor. The thermistor 15 is for detecting or sensing a surface temperature of the fusing roller 11 in an electric signal form, the thermostat 16 is for interrupting an electric power supply to the halogen lamp 12 when the surface temperature of the fusing roller 11 exceeds a given threshold, and the power switching part 19 is for switching a power supply of an AC power source 18 to the halogen lamp 12 according to a signal from a controller 20.
The thermistor 15 senses the surface temperature of the fusing roller 11, and transmits the sensed temperature to the controller 20. The controller 20 compares the sensed temperature with a set temperature, and regulates the power supply to the halogen lamp 12 through the power switching part 19, thereby maintaining the surface temperature of the fusing roller 11 in a print temperature suitable to fuse the toner image 14a and to fix it onto the sheet of printing paper 14.
The controller 20 usually controls the surface temperature of the fusing roller 11 by a temperature control process that includes an initial heating step of heating the surface temperature of the fusing roller 11 to a print standby temperature, a print standby step of maintaining the surface temperature of the fusing roller 11 at the print standby temperature and waiting a print command, and a printing step of maintaining the surface temperature of the fusing roller 11 higher than the print standby temperature to offset a loss in heat during the fusing operation of fusing the toner image.
At each of the operations of the temperature control process, the controller 20 controls the power supply to the halogen lamp 12, by comparing the sensed surface temperature of the fusing roller 11 with the set temperature and then turning on the halogen lamp 12 through the power switching part 19 when the detected temperature is below the set temperature and turning off the halogen lamp 12 when the detected temperature is over the set temperature, and thereby the surface temperature of the fusing roller 11 is maintained within a given range.
Also, the thermostat 16 functions as an overheating prevention means to protect the fusing roller 11 and its neighboring components, in case that the thermistor 15 and the controller 20 fail to regulate the surface temperature of the fusing roller 11.
However, the aforementioned fusing device is not without disadvantages. For example, in the conventional fusing device 10, since the halogen lamp 12 is turned on or off, regardless of a state or condition at each of the steps of the temperature control process for regulating the surface temperature of the fusing roller 11 in the print temperature, the electric power may not be efficiently supplied to the halogen lamp 12, thereby increasing power consumption and fluctuation in the surface temperature of the fusing roller 11 may be large.
When the fluctuation in the surface temperature of the fusing roller 11 is enlarged, the print temperature is unstably controlled, and thereby irregularly fusing the toner image onto the sheet of printing paper.

Temperature control method for use in a fusing device of an image forming apparatus having a fusing roller and a heater heating the fusing roller and image forming apparatus using the same


An apparatus for optimizing sub-pixel resolution in a triangulation based target distance measuring device at a desired stand-off distance has a laser light source projecting a light beam along a light beam axis so as to project a light spot onto a surface of a workpiece, a lens having an optical axis and a depth of focus dependant on the target distance, the lens for gathering light reflected from the light spot on the surface of the workpiece, a linear photodetector array of adjacent light detecting pixels, the array having a longitudinal array axis, the array for detecting light impinging the pixels and generating an output signal indicative of the position of the pixels being impinged by the light, the light beam axis, the optical axis, and the longitudinal array axis co-planar, the lens imaging the reflected light across and impinging the array so as to form an image across the array, the output signal indicative of an intensity profile of the image impinging the array, the image defocused to a near-Scheimpflug condition so as to optimize the output signal from the array, whereby movement of the surface of the workpiece relative to the distance measuring device while the light spot is projected onto the surface causes corresponding movement of the image along the array.

When processing logs in a sawmill, it is desirable to maximize the volume of the sawn lumber that can be obtained from any one log. It has been found useful to map the shape of raw wood and in particular logs or lumber, and process such information by means of optimizing algorithms so that the wood or the saw may be positioned to maximize the volume of boards cut.
In order to map the surface profile of a log or cant, remote sensors have been employed such as those taught in U.S. Pat. No. 5,056,922 which issued Oct. 15, 1991 to Cielo et al for a Method and Apparatus for Monitoring the Surface Profile of a Moving Work Piece. Cielo et al teaches an apparatus for three-dimensional surface profiling based on triangulation. Triangulation consists of projecting a beam of light to form a luminous spot on the surface to be profiled. It is the location of the luminous spot whose position is to be measured. Viewing the projected spot from an angle relative to the light beam, and determining the position of the reflected spot image allows the instantaneous distance to the surface of the log or cant to be gauged.
Cielo et al discloses a light projecting system which projects more than one discreet co-planar light beam onto the reflecting surface to be profiled, each light beam at a different angle of instance. An optical means such as a lens gathers the light beams reflected from the surface being profiled (hereinafter the "target surface") and images those reflected beams onto a means for detecting each of the light beams such as an array of photo-sensitive pixels. The photo-sensitive pixels, when struck by a light beam, generate an electrical signal. In the array, the location of the pixels generating such signals, relative to the light source, are indicative of distance to the target surface because of the triangulation geometry between the light source and the imaged spot on the array.
Cielo et al teaches using a line array photo-detector aligned relative to an objective lens so that the projection of their axes intersects at a point on the target surface, that is, the object plane, thus satisfying the so-called Scheimpflug condition for focusing a lens. Cielo et al describes this as ensuring that all of the projected light beam spots along the target surface are imaged on the line array detector in sharp focus. The one-dimensional line array detector has detecting elements, that is, pixels, disposed along the detector in a one-dimensional array. The pixels are elongated in a direction perpendicular to the longitudinal axis of the array. Cielo et al teaches using a wide aperture array, that is, an array having significantly elongated pixels (2.5 mm.times.15 .mu.m with 25 .mu.m spacing) in the line array detector so that the light beam spots, preferably having elliptically shaped cross sections, are imaged within the aperture of the array.
Cielo et al also teaches that the signal amplitude generated by a light spot hitting adjacent pixels in the photo-detector array, if plotted as signal amplitude versus position along the array, is a pulse having a gaussian distribution. Cielo et al further teaches that the position on the array of each light beam spot image must be located very precisely in order to obtain a good depth accuracy, that is, an accurate distance measurement from the sensor to the target surface whose profile is being mapped. In particular, Cielo et al teaches locating the centre of each pulse using an algorithm for determining what he refers to as the centre of gravity of the pulse. The centroid algorithm is as follows: EQU .mu.avg=.SIGMA..sub.i .mu..sub.i I(.mu..sub.i)!/.SIGMA..sub.i I(.mu..sub.i)!
where .mu..sub.i is the position of the i-th element along the array detector and I(.mu..sub.i) is the amplitude of the signal detected by this element, while .SIGMA. is a summation symbol. The centre of gravity computed according to this formula corresponds to the point of maximum signal amplitude of the pulse if the pulse is in fact gaussian, that is, smooth and symmetrical.
Cielo et al recognize however that the shape of such pulses may vary considerably because of speckle and thus a centroid approximation algorithm will not necessarily accurately estimate the position on the array of the maximum signal amplitude of the pulse. Accurately estimating the position of the pulse centroid allows for accurate mapping of the target surface. Cielo et al obtain what they describe as a smooth and constant pulse shape by their combination of a wide aperture array with an elliptically shaped light beam spot imaged as a focussed spot on the array. This allows averaging of the random fluctuations of a number of speckles within each pixel comprising the laser spot image.
The draw back of such a system is that a wide aperture array is required and the alignment of the light beams must be sufficiently accurate to place the imaged light beam spot fully onto the array in order that the stimulated pixels generate sufficient output signal strength to overcome the increased detector background noise associated with wide aperture arrays. Wide aperture arrays are also typically more costly and are slower to scan than conventional one-dimensional arrays having significantly smaller apertures.
Nosier, U.S. Pat. No. 4,248,532 which issued Feb. 3, 1981 for an Electro-optical Distance Measuring System also teaches that it is desirable that the light beam imaged spot on the array be in focus. Nosler discloses a triangulation based electro-optical sensor, similar in underlying principal to that taught by Cielo et al, to measure the position of, and thereby to map, the profile of the surface of logs being moved past the electro-optical distance measuring device. A laser beam is projected onto a log surface and the image of the beam reflection imaged by a lens onto a linear photo-detector array. The location of the image on the array is indicative of the distance to the log surface.
It is disclosed by Nosler that measuring logs requires a dynamic measurement range of between 8 inches and 48 inches and that it is desired to maximize the resolution accuracy of the reflected image so that such accuracy does not vary over the entire dynamic range. Nosier teaches that the angular positioning of the photo-detector array is critical to ensuring that throughout the dynamic range the reflected image on the array will always be in sharp focus. Nosier states that changes in focus of the image on the detector array will cause significant resolution accuracy differences.
In order that the reflected image on the array always be in sharp focus, Nosler teaches intersecting the axis of the light beam (which coincides in the Nosler device with the object plane of the device) with the interception point of the principal axis of the lens and the longitudinal axis of the photo-detector array so that all three axes intersect at one point, referred to by Nosler as the "known point". Intersection of all three axes at the known point also satisfies, as does impliedly the Cielo device (see FIG. 2), the Scheimpflug condition for focusing images of a reflected light beam onto a surface such as that of the photo-detector array. For a description of the Scheimpflug condition see for example: Scheimpflug, T(1906), `Der Photoperspektograph und seine Anwendung`, Photographische Korrespondenz 43, 516; Brown, N(1969), `Slit Image Photography`, Trans. Ophthal. Soc., 89, 397; G. Bickel, G. Hausler, and M. Maul, "Triangulation with expanded range of depth", Opt. Eng. 24(6), 975-977(1985).
The Scheimpflug condition is an approximation based on the assumption that the lens being used to focus the reflected image onto the photo-detector array surface may be modelled as a thin lens. That is, an assumption is made that the thickness of the lens element is small enough so that the effect of the lens thickness on the accuracy of the calculation of the known point may be neglected. For the purpose of such a thin lens approximation, the thickness of the lens is assumed to be zero. The principal points of the lens are thus assumed to be coincident. The principle plane of a thin lens is the plane which is normal to the optical axis of the lens and intersects the principal point which is on this same axis. The position of this plane at which it, the light beam axis and the longitudinal axis of the array intersect at a known point defines an orientation which satisfies the Scheimpflug condition. If it is assumed then, using the thin lens approximation, that the primary and secondary principal plane of the lens may be taken as coincident then that coincident plane or a chosen single reference plane, where it intersects the light beam axis and the longitudinal axis of the array locates the known point and satisfies the Scheimpflug condition.
Real lenses such as used in the present invention and such as are used in triangulation based electro-optical distance measuring devices of which the applicant is aware, have finite thicknesses and thus primary and secondary principal points, separated by known distances. For the purpose of comparing the characteristics of a real or thick lens with respect to the Scheimpflug condition, the terms primary and secondary planes have been used to define planes which are normal to the optical axis and intersect the primary and secondary principal points, respectively If the geometry of such a device is aligned to form a known point and thus satisfy the Scheimpflug condition, for example, by having the secondary principal plane intersect the point of intersection of the light beam axis with the longitudinal axis of the detector array, then it is only an approximation to state, as does Nosler, that focus is maintained over what Nosler refers to as the dynamic range. Such an approximation ignores the higher order effects of a real lens.
The reliance by Cielo et al and Nosier on the concept of focus is an oversimplification. That is, it is not only the focus achieved by a geometric alignment satisfying the Scheimpflug condition, in applications of which the present invention is one, that govern the resolution accuracy of a photodetection array in a triangulation based distance measuring device. Instead of "focus" per se, it is array output signal optimization which is desirable in devices using real lenses and conventional non-wide aperture photo-detector arrays such as the EG&G Reticon.TM. array, model number RL 1024DAG-020. Array output signal optimization means optimizing the signal to noise ratio from the array and optimizing the array resolution accuracy, i.e. the accuracy with which the centroid of a pulse may be located.
Concentrating solely on focus by strictly adhering to the Scheimpflug condition ignores other factors affecting array output signal optimization, vis:
(a) light beam intensity profile; PA1 (b) saturation of pixel output; PA1 (c) number of pixels covered by the light beam image; PA1 (d) standoff distance; PA1 (e) target range; and, PA1 (f) laser power setting. PA1 (a) defocusing the major optical elements to a near-Scheimpflug condition to achieve optimization according to the present invention; and PA1 (b) the specific manner of defocusing (i.e. defocusing the lens by moving the lens along the optical axis) to achieve specific optimized characteristics according to specific criteria. PA1 1. approximate as closely as possible to a Gaussian distribution the intensity profile of the image impinging the pixel array; PA1 2. maximize the amplitude of the intensity profile of the output signal of the array; PA1 3. minimize the saturation of the pixels in the array; and PA1 4. optimize the width of the image, normally within a range of the number of pixels between 10 and 35. With reference to criteria #1, Suzuki makes no references to a Gaussian distribution. Referring to criteria #2, Suzuki makes no mention of maximizing the image amplitude so as to utilize the full dynamic range of the detector elements. In fact, referring to FIG. 3, Suzuki provides examples of 2 acceptable signals labelled 13 and 14 where signal 14 has a peak amplitude that is 50% of that signal 13. This shows a lack of understanding of the importance of signal amplitude on sub-pixel resolution. Referring to criteria #3, again Suzuki makes no mention of signal level relative to element saturation level and thus did not recognize the importance of utilizing the full dynamic range of the detector array elements and the contribution of maximizing signal amplitude while minimizing pixel saturation in improving sub-pixel resolution. It is clear that although Suzuki may have been able to improve the sub-pixel resolution over the crude ranging devices in the prior art, his optical alignment criteria lacks the inventive aspects particularly pointed out and distinctly claimed in the present claims. PA1 (a) a laser light source for projecting a light beam along a light beam axis so as to project a light spot onto a surface of a workpiece; PA1 (b) a lens having an optical axis and a depth of focus dependant on the target distance, the lens for gathering reflected light from the light spot on the surface of the workpiece; PA1 (c) a linear photodetector array of adjacent light detecting pixels, the array having a longitudinal array axis, the array for detecting light impinging the pixels and generating an output signal indicative of the position of the pixels being impinged by the light, PA1 (1) approximate as closely as possible to a gaussian distribution the intensity profile of the image impinging the pixel array; PA1 (2) optimize the width of the image, normally within a range of the number of pixels between 10 and 35; PA1 (3) maximize the amplitude of the intensity profile of the output signal of the array; and, PA1 (4) minimize the saturation of the pixels in the array. Advantageously the optimized defocused location is within 20% of the lens' focused location, where such a percentage is defined as the distance between the optimized defocused location and the focused location relative to the depth of focus of the lens at a desired stand-off distance.
In what follows then, the "focus" position or known point refers to an alignment whereby the secondary principal lens plane intersects the intersection point of the light beam axis and the longitudinal axis of the photo-detector array. Alignments other than those satisfying the Scheimpflug condition are referred to as "de-focused". Thus, for example, translating the position of the lens along the lens axis so as to move the secondary principal plane off the known point is referred to as defocusing the lens.
Suzuki U.S. Pat. No. 4,575,237 describes a sub-pixel interpolation methodology for improving the distance measuring resolution of a triangulation based ranging device consisting of a source, collection lens, detector and processing electronics. The Suzuki method improved upon the prior art methods by converting the light level signals of a linear array of light detection elements into relative magnitudes. This resulted in a sampled light intensity distribution signal of the light incident on the array, that could be processed by electronic circuitry. The Suzuki method was based on fitting a curve to this sampled light intensity distribution and calculating the location of the peak of this curve. As a result, it was possible to interpolate between elements to a level greater than the 1/2 element level achieved in the prior art and thus improve the distance measurement of the device.
Since the Suzuki patent was based on detection of the extrema of a fitted curve, Suzuki was required to use at least a second order curve to fit to the data. In order to define a specific curve, the 3 coefficients a, b and c had to be determined. This required 3 x,y coordinates in order to generate the 3 equations necessary to solve for the 3 unknown coefficients. As a result, the method of Suzuki required the relative magnitude of at least 3 elements, in order to determine the coefficients of the quadratic curve and then the x,y coordinate of the peak of this function. As a result, the reference in column 4, lines 21-22 of the Suzuki reference where he mentions the need "to allow light intensity distributions 13 and 14 to have suitable extents of width" refers to the fact that Suzuki required the light level of at least 3 pixels to make a measurement of the peak. This criteria determined "the focus positions and the aberration correcting states of the light beam projecting and light receiving optical systems of the light measuring device". It did not means that the device was to be defocused, just that the point of focus was to be placed so that the beam of light was wide enough at the array to cover 3 pixels. Suzuki at all times assumed the use of a focused device. This is emphasized by Suzuki in the first full paragraph of column 2 of that reference, where defocus is identified as being detrimental, along with other factors associated with getting the reflected light to impinge at least 3 light sensitive elements such as reduction in the light receiving area of each light sensitive element, with its associated decrease in quantity of light. Thus Suzuki points away from defocus being a desirable attribute in a distance measuring device for optimizing output. Rather, defocus is relegated to a necessary evil, once to be avoided, but one which may be necessary to obtain sufficient image width for interpolation according to the Suzuki method.
The 3 element criteria of the Suzuki method is also illustrated in Figure in that both curves 13 and 14 are approximately 3.5 elements wide and would thus yield the coordinates necessary to determine the coefficients of a quadratic function.
The only criteria that Suzuki mentions is "suitable extents of width" which he indicates in the patent disclosure (column 3, line 63 to column 4, line 17 and in FIG. 3) to be 3 array elements.
Applicant notes that the Suzuki patent makes no mention in optimizing the optical configuration of his distance measurement system of:
For example, the lens is defocused so as to optimize the output signal according to the following criteria:
Referring to criteria #4, Suzuki's 3 pixel recommendation differs significantly from the 10 to 35 pixel recommendation outlined in the present application.
It is an object of the present invention consequently to provide a method and apparatus for optimizing the alignment of the three principal components, namely, the light source, the lens, and the photo-detector array, and for optimizing the output signal from the photo-detector array across the target range of interest.

Method and apparatus for optimizing sub-pixel resolution in a triangulation based distance measuring device


A method for correcting a cell voltage driftage in a NAND flash device is disclosed. An indicator indicating a cell voltage driftage in a memory unit of a NAND flash device is monitored by a processor. A cell voltage driftage in the NAND flash device is detected based at least in part on the indicator. One or more NAND commands correcting the cell voltage driftage are generated. The one or more NAND commands include a NAND command associated with changing a configuration setting of the NAND flash device.

In a storage media device system, data is typically read from NAND flash devices, and then the read data is processed by a decoder. For example, the decoder may be an error-correcting code (ECC) decoder enabling reconstruction of the original error-free data. Data retention is the ability of a memory bit to retain its data state over long periods of time. The data retention of NAND flash devices may be limited by charge leaking from the floating gates of the memory cell transistors. Furthermore, leakage is accelerated by high temperature or radiation. Program-erase cycles (P/E cycles) can also degrade a NAND flash device. Therefore, improved techniques that address the above problems in NAND flash devices would be desirable.

Hardware acceleration of DSP error recovery for flash memory


A photosensitive resin composition that excels in sensitivity to actinic energy rays (photosensitivity), is hardenable within a short period of time and can form pattern through development with a diluted aqueous alkali solution and that gives a cured film through thermal curing in the postcuring step, the cured film having satisfactory flexibility and being suitable to a solder mask ink of high insulation excelling in adherence and resistances of gold plating, electroless gold plating and tin plating; and a curing product thereof. In particular, a photosensitive resin composition characterized by comprising (1) a urethane resin (A) soluble in aqueous alkali solutions, the urethane resin obtained by urethanizing in the absence of catalyst a diisocyanate compound (a), a diol compound having an ethylenically unsaturated group in its molecule (b) and a diol compound having a carboxyl group in its molecule (c) optionally together with a diol compound not having any ethylenically unsaturated group or carboxyl group in its molecule (d) and reacting the reaction product with a cyclic acid anhydride (e); (2) photopolymerization initiator (B); and (3) a reactive crosslinking agent (C).

1. Field of the Invention
The present invention relates to a photosensitive resin composition using a polyurethane resin which is obtained by urethanization reaction without any catalyst followed by reaction with a cyclic acid anhydride and is soluble in aqueous alkali solution, and a manufacturing method of the curing product thereof. More specifically, the present invention relates to a resin composition to provide a curing product having excellent properties including such as developing property, flexibility, adhesion property, soldering heat resistance, chemical resistance, plating resistance and high insulation, etc. is useful for such as a solder mask for flexible print wiring board; an insulation film between layers for multilayer print wiring board; photosensitive light guide; and a manufacturing method of a curing product thereof; and to provide a base material and the like having a layer of the curing product.
2. Description of the Related Art
Conventionally, some part of print wiring board for personal use and most of print wiring board for industrial use are solder masks utilizing photolithograph. More specifically, an image is created by developing treatment after curing with exposure, and a photocuring composition which is finished with hardening with further heat and/or photo irradiation is used. A liquid composition for solder mask, which is a kind of alkali development using a diluted aqueous alkali solution as a developing solution, is mainly used because of environmental concerns. For example, a solder mask composition, as a liquid composition for solder mask which is an alkali development-type and uses a diluted aqueous alkali solution, comprising a photosensitive resin which is produced by addition of acid anhydride to the reaction product of novolac type epoxy resin and an unsaturated monobasic acid, a photopolymerization initiator, a crosslinking agent, and an epoxy resin has been disclosed. (Reference Patent 1, etc.) The curing product of the composition, however, is hard so that when it is applied to a Ball Grid Array (BGA) base board and a flexible base board, which recently are being used in many fields including portable equipments, unfortunately it causes a crack on the surface or it cannot afford a bending property.
Another composition including such as a polybasic acid anhydride modified epoxy acrylate resin produced by the reaction of the polybasic acid anhydride and the reaction product of polyfunctional bisphenol epoxy resin and (meth)acrylic acid, and an urethane acrylate has been disclosed as a material applicable to a BGA base board or a flexible base board in Reference Patent 2. When this is used, it cannot yet afford satisfactory flexibility and it cannot follow against extreme bending even though durability against cracking on the surface is improved.
Further, another resin composition which includes a urethane resin containing unsaturated group produced by a reaction of an unsaturated resin containing hydroxy group, which is produced by a reaction of 0.8 to 1.2 mole of an ethylenically unsaturated carboxylic acid having average molecular weight between 72 and 1000 containing average one carboxylic group and average one ethylenically unsaturated group in one molecule to one mole of epoxy group of diepoxide; a diol compound containing a carboxyl group; a diisocyanate compound; and a polyol compound as appropriate; has been disclosed in Reference Patent 3 and 4. However, if molecular weight is increased, the acid value of the resin also increases in a basis of resin design, and if a content of an ethylenically unsaturated group is increased to increase sensitivity, the acid value of the resin decreases, and therefore, because of such reason, it is difficult to get a well balanced molecular weight, sensitivity and developing property, and an optimization of the solder mask composition is problematic.
Photopolymeric resin composition which includes a urethane modified acid additional vinylester resin obtained by addition of polybasic acid anhydride to an urethane modified vinylester resin composed of vinylester resin obtained by a reaction of an epoxy compound including more than 1.2 epoxy group in one molecule and unsaturated monobasic acid has been disclosed in Reference Patent 5, but it has problematic electric property such as poor insulation property of its curing product, because urethane modified vinylester resin is produced by using a catalyst when the urethane is produced.    [Reference Patent 1] Japanese Laid Open Patent S61-243869    [Reference Patent 2] Japanese Patent 2868190    [Reference Patent 3] Japanese Laid Open Patent 2001-33959    [Reference Patent 4] Japanese Laid Open Patent 2001-33960    [Reference Patent 5] Japanese Laid Open Patent H9-52925
A highly precise and highly condensed print wiring board is demanded to minimize the size of portable equipment and increase communication speed. Accordingly higher grade solder mask is also demanded with maintaining more flexible property to increase electric properties such as gold plating resistance, electroless gold plating resistance, tin plating resistance, board adhesion property and high insulation property. Nonetheless the present known solder mask cannot satisfy these demands.

Photosensitive resin composition and curing product thereof


A laser device is disclosed which stabilizes impedance at laser drive initiation, and in which an oscillation at low current, a high reaction speed, a low noise, and the like are achieved. A semiconductor laser device includes first and second conductive type semiconductor layers, an active layer, and first and second electrodes. The second electrode comprises an ohmic electrode and a pad electrode. The first electrode is formed on the same planar side of the first conductive type semiconductor layer as the second electrode, and is disposed in the same direction as the pad electrode with respect to the ohmically connected region. The second conductive type semiconductor layer is set to a width that can secure light confinement on both sides of the ohmically connected region.

1. Field of the Invention
The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device that employs a Group III-V nitride semiconductor.
2. Discussion of the Related Art
In recent years, semiconductor lasers have been changing to smaller, more lightweight, more highly reliable, and higher output lasers, and they have been used as a light source for electronic devices such as DVD players, medical devices, and other similar devices. For these semiconductor devices, Group III-V nitride semiconductors are studied because they are capable of generating light at relatively short wavelengths.
For example, as shown in FIG. 6, a semiconductor laser includes nitride semiconductors comprising a GaN layer 21, an n-type GaN layer 22, an n-type AlGaN cladding layer 23, an n-type GaN light confinement layer 24, an active layer 25 (e.g., an InGaN multiple quantum well layer), a p-type GaN light confinement layer 26, a p-type AlGaN cladding layer 27, and a p-type GaN layer 28 onto a sapphire substrate 20 in this order. A ridge 29 is formed by etching a portion of the p-type AlGaN cladding layer 27 in the depth direction from the surface of the p-type GaN layer 28 (see, for example, Japanese Unexamined Patent Publication No. H10-256660).
In order to prevent a rise in operating voltage that causes an increase in the electrical resistance of the n-type GaN layer 22, this semiconductor laser will reduce the series resistance added to the laser device by shortening the distance between a p-type electrode 30 and an n-type electrode 31. Also, the semiconductor laser controls the excessive rise in the temperature of the devices. This allows reducing the operating voltage and increasing the reliability of the laser device.
Even if the serial resistance of the conventional semiconductor laser is reduced as described above, this semiconductor laser cannot achieve satisfactory characteristics depending on the type of semiconductor layer that has the active layer, and there are limits on the fields in which this device can be applied.
The present invention has taken the aforementioned problems into consideration, and has objects to provide a high performance and high quality semiconductor laser device that employs any type of semiconductor. In particular, the present invention employs Group III-V nitride semiconductors, which will achieve a stabilized initial laser drive impedance, and in turn an increase in the oscillation and response speeds, a reduction in noise, and the like.