A vertical power transistor is monolithically packaged on a semiconductor die with gate buffer circuitry. The gate buffer circuitry is adapted to deliver a biasing voltage to a gate contact of the vertical power transistor for switching the device between an ON state and an OFF state. By monolithically packaging the gate buffer circuitry together with the vertical power transistor, parasitic inductance between the gate buffer circuitry and the gate of the vertical power transistor is minimized, thereby decreasing the switching time of the vertical power transistor and reducing switching noise.

A vertical transistor is a type of transistor that is adapted for use in high power applications. An exemplary vertical transistor device is a vertical power metal-oxide field effect transistor (MOSFET), wherein a source and gate contact are located on a first surface of the vertical MOSFET device that is separated from a drain contact by a drift layer formed on a substrate. Vertical MOSFETs are sometimes referred to as vertical diffused MOSFETs (VDMOSFETs) or double-diffused MOSFETs (DMOSFETs). Due to their vertical structure, the voltage rating of a power MOSFET is a function of the doping concentration and thickness of the drift layer. Accordingly, high voltage power MOSFETs may be achieved with a relatively small footprint.
FIG. 1 shows an exemplary vertical power transistor 10. The power transistor 10 includes a substrate 12, a drift layer 14 formed over the substrate 12, one or more junction implants 16 in the surface of the drift layer 14 opposite the substrate 12, and a junction gate field effect transistor (JFET) region 18 between each one of the junction implants 16. Each one of the junction implants 16 is formed by an ion implantation process, and includes a deep well region 20, a base region 22, and a source region 24. Each deep well region 20 extends from a corner of the drift layer 14 opposite the substrate 12 downwards towards the substrate 12 and inwards towards the center of the drift layer 14. The deep well region 20 may be formed uniformly or include one or more protruding regions. Each base region 22 is formed vertically from the surface of the drift layer 14 opposite the substrate 12 down towards the substrate 12 along a portion of the inner edge of each one of the deep well regions 20. Each source region 24 is formed in a shallow portion on the surface of the drift layer 14 opposite the substrate 12, and extends laterally to overlap a portion of the deep well region 20 and the base region 22, without extending over either. The JFET region 18 defines a channel width 26 between each one of the junction implants 16.
A gate oxide layer 28 is positioned on the surface of the drift layer 14 opposite the substrate 12, and extends laterally between a portion of the surface of each source region 24, such that the gate oxide layer 28 partially overlaps and runs between the surface of each source region 24 in the junction implants 16. A gate contact 30 is positioned on top of the gate oxide layer 28. Two source contacts 32 are each positioned on the surface of the drift layer 14 opposite the substrate 12 such that each one of the source contacts 32 partially overlaps both the source region 24 and the deep well region 20 of one of the junction implants 16, respectively, and does not contact the gate oxide layer 28 or the gate contact 30. A drain contact 34 is located on the surface of the substrate 12 opposite the drift layer.
In operation, when a biasing voltage below the threshold voltage of the power transistor 10 is applied to the gate contact 30, a junction between each deep well region 20 and the drift layer 14 is reverse biased, thereby placing the power transistor 10 in an OFF state. In the OFF state of the power transistor 10, any voltage between the source contacts 32 and the drain contact 34 is supported by the drift layer 14. Due to the vertical structure of the power transistor 10, large voltages may be placed between the source contacts 32 and the drain contact 34 without damaging the device.
FIG. 2 shows operation of the power transistor 10 when the device is in an ON state. When a positive biasing voltage is applied to the gate contact 30 of the power transistor 10, an inversion channel layer 36 is formed at the surface of the drift layer 14 underneath the gate contact 30, thereby placing the power transistor 10 in an ON state. In the ON state of the power transistor 10, current (shown by the shaded region in FIG. 2) is allowed to flow from each one of the source contacts 32 through the inversion channel layer 36 and into the JFET region 18 of the drift layer 14. Once in the JFET region 18, current flows downward through the drift layer 14 towards the drain contact 34. An electric field presented by junctions formed between the deep well region 20, the base region 22, and the drift layer 14 constricts current flow in the JFET region 18 into a JFET channel 38. At a certain distance from the inversion channel layer 36 when the electric field presented by the junction implants 16 is diminished, the flow of current is disturbed laterally, or spread out in the drift layer 14, as shown in FIG. 2, before reaching the drain contact 34.
When switching between the OFF state and the ON state, the power transistor 10 may require a large input current at the gate contact 30, which generally cannot be provided by a standard control signal. Accordingly, gate buffer circuitry is coupled to the gate contact 30 of the power transistor 10 in order to deliver the necessary current to operate the device. The gate buffer circuitry is adapted to accept a low-current control signal and deliver a high-current output signal for driving the gate contact 30 of the power transistor 10.
FIG. 3 shows the power transistor 10 coupled to conventional gate buffer circuitry 40 for switching the power transistor 10 between an OFF state and an ON state. The conventional gate buffer circuitry 40 is constructed on a semiconductor die that is discrete and separate from the die on which the power transistor 10 is formed. The conventional gate buffer circuitry 40 includes a first PMOS transistor device 42 and a second NMOS transistor device 44 surrounded by a gate buffer substrate 46. The first PMOS transistor device 42 includes a body region 48 that surrounds a first implant well 50 and a second implant well 52, such that the first implant well 50 and the second implant well 52 are laterally separated within the body region. A gate oxide layer 54 is located on the surface of the body region 48, such that the gate oxide layer 54 partially overlaps and runs between the first implant well 50 and the second implant well 52. A gate contact 56 is located on top of the gate oxide layer 54. A source contact 58 is located on the surface of the second implant well 52, and a drain contact 60 is located on a surface of the second implant well 50, such that neither the source contact 58 nor the drain contact 60 contact the gate oxide layer 54 or the gate contact 56.
The second NMOS transistor 44 is also located in the gate buffer substrate 46, and includes a first implant well 62 and a second implant well 64. A gate oxide layer 66 is located on the surface of the gate buffer substrate 46, such that the gate oxide layer 66 partially overlaps and runs between the first implant well 62 and the second implant well 64. A gate contact 68 is located on top of the gate oxide layer 66. A source contact 70 is located on the surface of the first implant well 62, and a drain contact 72 is located on the surface of the second implant well 64, such that the source contact 70 and the drain contact 72 do not contact the gate oxide layer 66 or the gate contact 68.
The gate contact 56 of the first PMOS transistor device 42 is coupled to an input node 74. The source contact 58 of the first PMOS transistor device 42 is coupled to a supply voltage VDD. The drain contact 60 of the first PMOS transistor device 42 is coupled to an output node 76. The gate contact 68 of the second NMOS transistor device 44 is coupled to the input node 74. The source contact 70 of the second NMOS transistor device 44 is coupled to ground. The drain contact 72 of the second NMOS transistor device 44 is coupled to the output node 76. The gate contact 30 of the power transistor 10 is coupled to the output node 76 of the conventional gate buffer circuitry 40 via a wire bond 78 or a similar connection.
FIG. 4 shows a circuit diagram illustrating the equivalent circuit for the power transistor 10 and the conventional gate buffer circuitry 40 shown in FIG. 3. As described above, the first PMOS transistor device 42 includes a source contact 58 coupled to a supply voltage VDD, a drain contact 60 coupled to an output node 76, and a gate contact 56 coupled to an input node 74. The second NMOS transistor device 44 includes a drain contact 72 coupled to the output node 76, a source contact 70 coupled to ground, and a gate contact 68 coupled to the input node 74. The gate contact 30 of the power transistor 10 is coupled to the output node 76 of the conventional gate buffer circuitry 40. The drain contact 34 of the power transistor 10 may be used as a switching input, and the source contact 32 of the power transistor 10 may be used as a switching output.
In operation, when a control voltage VIN below the threshold voltage of the second NMOS transistor device 44 is applied to the input node 74 of the conventional gate buffer circuitry 40, the first PMOS transistor device 42 is placed in an ON state of operation, while the second NMOS transistor device 44 is placed in an OFF state of operation. Accordingly, the supply voltage VDD is delivered to the gate contact 30 of the power transistor 10, thereby placing the power transistor 10 in an ON state of operation. In the ON state of operation of the power transistor 10, a signal placed at the source contacts 32 of the power transistor 10 is delivered to the drain contact 34.
When a control voltage VIN higher than the supply voltage VDD less the threshold voltage of the first PMOS transistor device 42 is applied to the input node 74 of the conventional gate buffer circuitry 40, the first PMOS transistor device 42 is placed in an OFF state of operation, while the second NMOS transistor device 44 is placed in an ON state of operation. Accordingly, the gate contact 30 of the power transistor 10 is grounded, thereby placing the power transistor 10 in an OFF state of operation. In the OFF state of operation of the power transistor 10, a signal placed at the source contacts 32 of the power transistor 10 is not delivered to the drain contact 34.
Because the power transistor 10 is discrete and separate from the conventional gate buffer circuitry 40, the wire bond 78 used to couple the power transistor 10 to the conventional gate buffer circuitry 40 must be of significant length. Due to the length of the wire bond 78, parasitic inductance is introduced between the output node 76 of the conventional gate buffer circuitry 40 and the gate contact 30 of the power transistor 10. The parasitic inductance causes distortion in the output signal of the power transistor 10 and reduces the switching speed of the device.
Accordingly, there is a need for gate buffer circuitry that is capable of delivering the necessary current for operation of a power transistor device while reducing distortion in the output signal of the power transistor and reducing switching times.

Vertical power transistor with built-in gate buffer


One feature pertains to a multi-chip module that comprises at least a first integrated circuit (IC) die and a second IC die. The second IC die has an input/output (I/O) node electrically coupled to the first IC die by a through substrate via. The second die's active surface also includes a fuse that is electrically coupled to the I/O node and adapted to protect the second IC die from damage caused by an electrostatic discharge (ESD). In particular, the fuse protects the second IC die from ESD that may be generated as a result of electrically coupling the first die to the second die during the manufacturing of the multi-chip module. Upon coupling the first die to the second die, the fuse may bypass the ESD current generated by the ESD to ground. After packaging of the multi-chip module is complete, the fuse may be blown open.

1. Field
Various features relate to integrated circuits (ICs), and more particular/to electrostatic protection for stacked multi-chip integrated circuits.
2. Background
The ever increasing demand for smaller, lighter, and faster portable electronic devices, such as mobile phones and laptop computers, has encouraged the electronics industry to create circuit components having greater capacity, performance, and smaller dimensions. For example, portable devices may now contain integrated circuit (IC) packages having two or more semiconductor dies stacked vertically and encased within the same molding compound of the IC package. Such multi-chip IC packages may be commonly referred to as "chip stack multi-chip modules" (MCM). According to one technique called "through silicon stacking" (TSS), the vertically stacked multiple semiconductor dies are electrically coupled to one another using through substrate vias (TSVs). TSVs are electrical conductors typically made of metal that pass vertically through the thickness of a die's substrate such that one end is exposed at a back side surface of the die substrate, and another, opposite end is electrically coupled to the active surface of the die.
FIG. 1 illustrates, a schematic, cross-sectional side view of a TSS MCM 100 found in the prior art. The MCM 100 includes a plurality of semiconductor dies 102a, 102b, 102c that are electrically coupled to one another using TSVs 104a, 104b, 104c. The top die 102a has an active surface 106a that includes a plurality of integrated circuit components (e.g., transistors, capacitors, inductors, resistors, etc.), and a back side surface 108a. The TSV 104a is electrically coupled to the active surface 106a and runs through the thickness of the die's 102a substrate. Similarly, the middle and bottom dies 102b, 102c each have active surfaces 106b, 106c and back side surfaces 108b, 108c. The middle die's TSV 104b is electrically coupled to the middle die's active surface 106b, and the bottom die's TSV 104c is electrically coupled to the bottom die's active surface 106c.
The TSVs 104a, 104b, 104c have contact pads 110a, 110b, 110c at one end and contact pad receivers 105a, 105b, 105c at an opposite end. Each dies' active surface 106a, 106b, 106c may be electrically coupled to its respective TSV 104a, 104b, 104c. The contact pads 110a, 110b, 110c are exposed at the dies' front side active surfaces 106a, 106b, 106c, and the contact pad receivers 105a, 105b, 105c are exposed at the dies' back side surfaces 108a, 108b, 108c. The contact pads 110a, 110b, 110c are metal "microbumps" and the contact pad receivers 105, 105b, 105c may be metal indentations on the dies that have a corresponding curvature to receive and mate to the microbumps 110a, 110b, 110c.
The top die's contact pad 110a is physically and electrically coupled to the middle die's contact pad receiver 105b, and the middle die's contact pad 110b is physically and electrically coupled to the bottom die's contact pad receiver 105c. In this fashion, the dies' active surfaces 106a, 106b, 106c, are electrically coupled to one another through the vias 104a, 104b, 104c.
The bottom die 102c is physically and electrically coupled in a flip chip fashion to a package substrate 112 (e.g., laminate substrate, metal based substrate, such as copper based substrate, etc.) with an underfill and/or epoxy 115. The package substrate 112 may include multiple layers having a plurality of interconnections not shown) there between. The interconnections in turn may be electrically coupled to a plurality of soldering balls 114 that form a ball grid array (BGA) that the MCM 100 uses to electrically couple to a printed circuit board (not shown). The components of the MCM 100, including the dies 102a, 102b, 102c, the TSVs 104a, 104b, 104c, and at least a portion of the substrate 112 may be encased in a molding compound 116.
FIG. 2 illustrates the process of electrically and physically coupling the top die 102a to the middle die 102b during manufacturing of the MCM 100. In the illustrated example, the molding compound 116 (See FIG. 1) has been removed to show how the top die 102a is placed onto the middle die 102b (the three directional arrows in FIG. 2 illustrate the motion of the top die 102a toward the middle die 102b). During this process, the top die 102a is moved close to the middle die 102b, and stacked on top such that the contact pad 110a of the top die 102a mates with the contact pad receiver 105b of the middle die 102b. However, sometimes the top die 102a may have an electrostatic potential that is substantially different (e.g. much greater or much less) than the middle die 102b, which may be grounded. When the two dies 102a, 102b get sufficiently close (e.g., upon contact), an electrostatic discharge (ESD) event (i.e., static electricity) may be triggered such that a relatively large amount of current momentarily flows through the TSV 104b of the middle die 102b. Without proper ESD protection circuitry, sensitive IC components (such as buffer circuit transistors) located on the middle die's active surface 106b that are electrically coupled to the TSV 104b may be damaged from the ESD event. In some cases, circuitry located on the active surface 106a of the top die 102a may also be damaged. Similarly, other dies within the MCM 100 are also prone to such ESD harm, including the bottom die 102c when the middle die 102b is electrically and physically coupled to the bottom die 102c.
FIG. 3 illustrates a schematic of an ESD protection circuit 300 found in the prior art that may be coupled to the middle die's TSV 104b to protect the middle die's 102b circuitry 310 from ESD damage. The ESD protection circuit 300 features diodes 302, 304 that form a shunt which bypasses the ESD current away from the sensitive circuitry 310, which may be, for example, an output signal buffer.
Although the ESD protection circuit 300 may be effective in protecting the output signal buffer 310 from ESD damage, the ESD protection circuit 300 has notable disadvantages. For example, the diodes 302, 304 may occupy significant silicon/die area due to their relatively large size that is needed to accommodate the high ESD current flow. Moreover, the diodes 302, 304 create parasitic effects at the TSV 104b output node 306, including parasitic capacitance and/or inductance. To compensate for these parasitic effects, the buffer 310 size may have to be larger so that it can sufficiently drive the output signal at the output node 306. A larger buffer 310 consumes more power and also takes up more active silicon/die area. Therefore, the silicon/die area devoted to the ESD protection circuitry 300 directly (e.g., diode 302, 304 component area) and indirectly (e.g., larger buffer 310) uses active surface area that may otherwise be used for other IC components.
Thus, there is a need for advanced ESD protection circuits that adequately protect dies of an MCM without suffering from the aforementioned size and power consumption issues.

Electrostatic protection for stacked multi-chip integrated circuits


A new variety of Hybrid Tea rose plant producing yellow flowers of good form and suitable for growing under glass.

The present invention relates to a new and distinct variety of rose plant of the hybrid tea rose class which was discovered as a natural mutation in a controlled planting of `Ruicrevi` U.S. Plant pat. No. 9,421 in Schipluiden, The Netherlands. The varietal denomination of the new variety is `Ruiyel`. The new variety was isolated and asexually reproduced by budding in The Netherlands.


A storage area network management and configuration system is provided. The system includes an enterprise network that has a plurality of computer systems, and some of the plurality of computer systems include a server component, some include a client component, and some include both the client component and the server component. The system also includes a storage enclosure that is connected to a computer system having at least the server component. A graphical user interface window is provided by the client component, and the graphical user interface provides a graphical representation and icon links to configuration tools for controlling the drives and arrays of the storage enclosure. In one aspect, the enterprise network can include a plurality of storage enclosures that are connected to selected computer systems that are part of the enterprise network and that have the server component. Through the configuration tools, any one of the drives in the storage enclosures can be configured into a particular RAID-based array, monitored for failures, and modified to meet different storage needs. The modification can, in one aspect, be performed by simply dragging configuration template icons over selected hardware storage devices.

1. Field of the Invention
This invention relates generally to storage area networks, and more particularly to systems for configuring and managing storage devices connected over a network.
2. Description of the Related Art
As the need for reliable storage solutions increase across a company network, computer network and storage experts have been designing network solutions that incorporate one or more redundant array of inexpensive disks (RAIDs). RAID is a storage technology wherein a collection of multiple disk drives is organized into a disk array managed by a common array controller. The array controller presents the array to the user as one or more virtual disks. Disk arrays are the framework to which RAID functionality is added in functional levels to produce cost-effective, highly available, high-performance disk systems.
Although RAID provides the reliability network administrators are looking for, setting up a disk array to work in accordance with a given RAID level is not always straight forward for a network or computer administrator having a typical level of RAID experience. For instance, RAID level 0 is a performance-oriented striped data mapping technique. Uniformly sized blocks of storage are assigned in a regular sequence to all of the disks in the array. RAID 0 provides high I/O performance at low cost. Reliability of a RAID 0 system is less than that of a single disk drive because failure of any one of the drives in the array can result in a loss of data.
RAID level 1, also called mirroring, provides simplicity and a high level of data availability. A mirrored array includes two or more disks wherein each disk contains an identical image of the data. A RAID level 1 array may use parallel access for high data transfer rates when reading. RAID 1 provides good data reliability and improves performance for read-intensive applications, but at a relatively high cost.
RAID level 2 is a parallel mapping and protection technique that employs error correction codes (ECC) as a correction scheme, but is considered unnecessary because off-the-shelf drives come with ECC data protection. For this reason, RAID 2 has no current practical use, and the same performance can be achieved by RAID 3 at a lower cost. As a result, RAID 2 is rarely used.
RAID level 3 adds redundant information in the form of parity data to a parallel accessed striped array, permitting regeneration and rebuilding of lost data in the event of a single-disk failure. One stripe unit of parity protects corresponding stripe units of data on the remaining disks. RAID 3 provides high data transfer rates and high data availability. Moreover, the cost of RAID 3 is lower than the cost of mirroring since there is less redundancy in the stored data.
RAID level 4 uses parity concentrated on a single disk to allow error correction in the event of a single drive failure (as in RAID 3). Unlike RAID 3, however, member disks in a RAID 4 array are independently accessible. Thus RAID 4 is more suited to transaction processing environments involving short file transfers. RAID 4 and RAID 3 both have a write bottleneck associated with the parity disk, because every write operation modifies the parity disk.
In RAID 5, parity data is distributed across some or all of the member disks in the array. Thus, the RAID 5 architecture achieves performance by striping data blocks among N disks, and achieves fault-tolerance by using 1/N of its storage for parity blocks, calculated by taking the exclusive-or (XOR) results of all data blocks in the parity disks row. The write bottleneck is reduced because parity write operations are distributed across multiple disks.
The RAID 6 architecture is similar to RAID 5, but RAID 6 can overcome the failure of any two disks by using an additional parity block for each row (for a storage loss of 2/N). The first parity block (P) is calculated with XOR of the data blocks. The second parity block (Q) employs Reed-Solomon codes.
As can be appreciated, even the most knowledgeable computer administrators are required to have a good working understanding of RAID and the ability to select the correct hardware to make the storage solution work. To facilitate this, some companies provide preconfigured RAID arrays, which can be connected to a computer system, such as, a server computer or a cluster. Although the these RAID solutions provide good data storage reliability, a computer technician/administrator is required to initially configure the RAID solution on a system and then continually monitor its health over its lifetime.
For instance, once the RAID solution is correctly configured, the computer technician/administrator should plan on making trips to the server so that the health of each of the individual disks in the RAID solution can be monitored. This is generally required because RAID solutions, by their very nature, will not completely fail when only one of the disks stop working. However, if more than one disk fails, the RAID solution may be unable to guard against data loss. Although this might not appear to be a big task, as the company enterprise networks continues to expand, there may be a need for multiple RAID solutions at each server computer (i.e., server or cluster). As a result, there will be an ever growing need to configure RAID solutions, monitor the health of each RAID solution and repair and/or rebuild RAID solutions as the storage needs of the company grow and change.
In view of the foregoing, there is a need for an easy-to-use system for configuring, managing, and monitoring RAID storage systems over a network.


A diaper changing assistance device. The diaper changing assistance device provides efficiency to a parent changing a diaper of an infant. A rod is attached between an infant's ankles by a pair of ringed members. The rod can be freely lifted by the parent so that the parent is able to change the diaper of the infant with reducing flailing and movement of the infant.

The present invention relates to a diaper changing assistance device. Changing an infant's diaper is a challenging task for many parents. Because of how diapers are packaged and because of how active infants can be, a parent must normally hold an infant's legs while simultaneously applying the diaper. Furthermore, Infants frequently flail their legs, making the diaper changing process more difficult. In addition to these difficulties and the amount of time that the diaper changing process can take, an unpleasant mess can be created that will require even more time and effort to clean up.
Because of the lack of such a device in the known art, there is a need for a diaper changing assistance device that provides parents with the ability to change their infant child's diaper in a safe and efficient manner.


In a servo controller according to the invention, a position feedback correction unit (3) calculates a first-axis position feedback signal (pmfb1) based on a first-axis position (pm1) as a self-axis position, and a second-axis position (pm2) as an other-axis position; and a deviation between a model position (pa1) and the first-axis position feedback signal (pmfb1) is inputted from a subtracter (5) to a position control unit (4), which performs positional control to output a velocity command. A velocity feedback correction unit (6) calculates a first-axis velocity feedback signal (wmfb1) from a first-axis velocity (wm1) as the self-axis velocity, and a second-axis velocity (wm2) as the other-axis velocity; and the velocity control unit (8) adds a model velocity (wa1) and the velocity command outputted from the position control unit (5), and subtracts the first-axis velocity feedback signal (wmfb1) therefrom, and outputs a feedback torque command (Tfb1) based on the corrected velocity command.

There has been a biaxial driving machine in which a moving table is supported by two ball screws disposed in parallel, and is driven by synchronously controlling two servomotors that are connected respectively to the two ball screws. The moving table in the biaxial driving machine installs, in general, an upper structure that is movable, and the center of gravity of the moving table varies according to the position of the upper structure, the load supported by the upper structure, and the like.
Moreover, a position control device for a motor has been disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 30578/1994) as related to position control devices for motors (direct-current motors, induction motors, synchronous motors, etc.) that drive load devices such as a table in a machining apparatus and arms of an electric industrial robot.
Patent Document 1 aims to realize a position control device for motors, which has a high-speed response, prevents throb of machinery, and has a constant response frequency at all times even if the inertia moment of the load device varies. In the position control device for motors in Patent Document 1 (line 23 through line 36 in the right column in page 5), a first velocity signal is acquired by means of a first position control circuit, and a second velocity signal is acquired by means of a second position control circuit for controlling a mechanical simulation circuit. In addition, the first and second velocity signals are added to acquire a third velocity signal, and a first torque signal is acquired by means of a first velocity control circuit, to which the third velocity signal has been inputted. Likewise as above, second and third torque signals are acquired by means of second and third velocity control circuits, and the torque generated in the motor is controlled so as to follow the final torque signal calculated by adding the first through the third torque signals.
The position control device for motors in Patent Document 1 includes the second position control circuit, the second velocity control circuit, and the mechanical simulation circuit, whereby there is a benefit in that the response of the positional control with respect to the changing of a rotation angle command signal can be enhanced. In addition, by including the third velocity control circuit, there is a benefit in that the response of the positional control with respect to the changing of the load torque can be also enhanced.
Moreover, as related to control systems for synchronously positioning legs on both ends of a machining apparatus having a movable structure of a gate form or the like, a synchronous position control device has been disclosed in Patent Document 2 (Japanese Patent Laid-Open No. 226206/1987), which aims to achieve a synchronous position control system that does not generate asymmetry due to disturbance.
In Patent Document 2 (line 3 through line 10 in the lower left column in page 2), in a system in which on both sides of the movable structure, position control systems that move along both the sides according to position command values are provided, and in which the position control systems synchronously position both ends of the movable structure, a problem of asymmetry due to disturbance has been resolved by calculating the difference between movement positions of both the ends of the movable structure, calculating compensation values by applying compensation elements on the difference, and feeding back the compensation values to the respective position control systems.
When the position control device for motors in Patent Document 1 described above is applied to control of a biaxial driving machine, if load inertias of two axes are balanced, the first axis and the second axis identically move, whereby appropriate driving can be performed. However, when the inertias of the two axes are unbalanced, because movements of the first axis and the second axis do not coincide, a deviation (between-axes positional deviation) arises between the actual position of the first axis and the actual position of the second axis. There has been a problem in that the between-axes positional deviation degrades positioning accuracy of the moving table and generates stress on the machine, which shortens the machine life, and may cause damage on the machine at worst.
Therefore, there has been a problem in that the position control device for motors in Patent document 1 described above cannot be applied to the control of a biaxial driving machine in which large load unbalance is present.
Meanwhile, the synchronous position control system in Patent Document 2 described above feeds back the difference between the positions in the two position control systems (between-axes positional deviation) to the two position command values to resolve asymmetry. When the control system is applied to the control of a biaxial driving machine, a certain level of the between-axes positional deviation can be suppressed; however, in order to suppress a large between-axes positional deviation, a response of a position command correction unit (coefficient H1 here) must be set to an extremely large value. When the response of the position command correction unit is set to an extremely large value, although a high-rigidity machine has no problem, a low-rigidity machine has a problem in that the system sometimes gets unstable, because oscillation of the machine is caused, for example.
Moreover, setting the gain to a high value sometimes encourages a conflict between axes, which is generated when position detection errors or the like are present. There has been a problem in that, when a conflict between axes arises, the motor generates heat due to the pulling torque between axes, which prevents high-speed and highly accurate control, and the machine might be damaged due to the pull between axes at worst
Therefore, there has been a problem in that the synchronous position control device in Patent Document 2 described above cannot be applied to a low-rigidity machine or a machine in which position detection errors are present.
The present invention has been made to resolve the problems described above, and aims to realize a servo controller that is applicable to a low-rigidity machine or a biaxial driving machine in which position detection errors are present.


A method and apparatus for maintaining a substantially constant belt tension under changing temperature conditions is provided by a geometric layout of a motor, belt and pulley system and a selection of manufacturing materials for component parts having a predetermined relationship of thermal expansion coefficients between themselves.

1. Field of the Invention
The present invention relates generally to belt drives, more specifically to hard copy apparatus having a scanning carriage for translating writing instruments across print media and, more particularly, to a thermal compensation belt drive tensioner for a scanning ink-jet printer carriage.
2. Description of Related Art
The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, and facsimile machines employ ink-jet technology for producing hard copy. The basics of this technology are disclosed for example, in various articles in the assignee""s Hewlett-Packard Journal, Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No.1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in Output Hardcopy [sic] Devices, chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press. San Diego, 1988).
FIG. 1 depicts a hard copy apparatus, in this exemplary embodiment a computer peripheral, ink-jet printer, 101. A housing 103 encloses the electrical and mechanical operating mechanisms of the printer 101. Operation is administrated by an electronic controller 102 (usually a microprocessor or application specific integrated circuit (xe2x80x9cASICxe2x80x9d) controlled printed circuit board) connected by appropriate cabling to a computer (not shown). It is well known to program and execute imaging, printing, print media handling, control functions and logic with firmware or software instructions for conventional or general purpose microprocessors or with ASIC""s. Cut-sheet print media 105, loaded by the end-user onto an input tray 120, is fed by a suitable paper-path transport mechanism (not shown) to an internal printing station, or xe2x80x9cprint zone,xe2x80x9d 123 where graphical images or alphanumeric text is created. A carriage 109, selectively positionable on a rod 111, scans the print medium. An encoder subsystem 113 is provided for keeping track of the position of the carriage 109 at any given time. A set of individual ink-jet pens, or print cartridges, 115X is mounted in the carriage 109 (generally, in a full color system, inks for the subtractive primary colors, cyan (X=C), yellow (X=Y), magenta (X=M) and true black (X=K) are provided; in some implementations an ink-fixer chemical (X=F) is also used). An associated set of replaceable or refillable ink reservoirs 117X is coupled to the pen set by ink conduits 119. Once a printed page is completed, the print medium is ejected onto an output tray 121. The carriage scanning axis is conventionally designated the x-axis, the print media transit axis is designated the y-axis, and the printhead firing direction is designated the z-axis. For convenience in describing the art and the present invention, all types of ink-jet hard copy apparatus are sometimes hereinafter referred to as xe2x80x9cprinters;xe2x80x9d all types, sizes, and compositions of print media are also referred to as xe2x80x9cpaper;xe2x80x9d all compositions of colorants are sometimes referred to as xe2x80x9cink;xe2x80x9d and all embodiments of an ink-jet writing instruments are sometimes hereinafter simply referred to as a xe2x80x9copen;xe2x80x9d no limitation on the scope of the invention is intended nor should any be implied.
Generally, a belt drive subsystem can be used to mount and selectively move the carriage 109 for scanning bidirectionally across the print zone 123. Instantaneous positioning of the printhead to the print medium is critical to prevent a printing error and ensure throughput performance. Belt tension is an important parameter and is varied dependent primarily on the drive loads required, margin desired, and belt-pulley design.
FIG. 2 (PRIOR ART) illustrates a belt 100 connected to a reversible motor 300 and a pulley 500, both of which are usually affixed to a printer housing framework (not shown). A pulley axle 700 fits slidingly in slots 900 in a mounting frame 110. Assembled, the belt 100 extends through an aperture 130 in the frame 110. The pen carriage 109 (not seen in this view) rides on a guide rod 111 as in FIG. 1 and is attached to the belt 100. Since the pulley axle 700 makes a sliding fit and the belt must be long enough to reach beyond the end 170 of the mount 110 to encircle the pulley 500 before it is fit into the slots 900, a spring loaded tensioner 190 is used to achieve the proper post-assembly tension. After the pulley 500 is fit into the slots 900, the tensioner 190 is inserted such that the axle 700 will ride on a tensioner surface 210. An extension table 230, with a tensioning spring 250 surrounding it, is rotatingly slipped into slot 270 of the mount 110. By designing to a close tolerance, the tensioner surface 210 will pull the pulley outward along the slots 900 just until the belt 100 is properly tensioned. Another spring loaded tensioner is shown in U.S. Pat. No. 4,761,154, filed by Beauchamp et al. for a BELT TENSIONER (assigned to the common assignee herein and incorporated herein by reference).
Another prior art design, that has a lower belt tension requirement over the spring loaded design, is the standard fixed center tensioner that includes a spring loaded belt tensioner that provides initial belt tension and a locking mechanism to fix the tensioner to a predetermined setting. As the belt stretches under load and during thermal and humidity excursions, the hardware expands and contracts, resulting in changing pulley center-to-center spacing. The result is a change in belt tension from the initial setting.
In such solutions, as the belt stretches under load and during thermal and humidity excursions, the hardware can also expand and contract, resulting in a spring deflection and, therefore, a belt tension change. Such systems are designed with the lowest possible spring rate so that such a tension change is minimized. However, at higher acceleration and deceleration loading and higher scanning speeds which increase printing throughput, belt tensions must be increased to prevent belt slip at the motor and pulley interfaces. Moreover, for an ink-jet implementation, due to the advancement in pen design and increasing the number of printheads on-axis (or, for disposable or refillable print cartridges having a self-contained, on-axis, ink supply where the cartridge size is increasing to meet the demand for full bleed printing (e.g., photographic reproductions)), the total carriage weight increases. Increasing belt tension increases loading on the motor axle bearings. One solution is to add precision bearings to the motor shaft, but only at a significant cost impact on manufacturing. During temperature and humidity excursions, the material will experience an expansion or contraction (xe2x80x9cECxe2x80x9d) proportional to the respective material coefficient of thermal expansion (xe2x80x9cCTExe2x80x9d). Note that CTE can be a positive or negative value. Depending upon the materials used in fabricating the mechanism, differing material CTE may generate a belt tension increase or decrease during temperature excursions.
There is a need for a method and apparatus to maintain a substantially constant belt tension during temperature changes, There is a need for a method and apparatus to run relatively low belt tensions in high speed printers to increase motor life. There is also a need for a low cost solution.
In its basic aspects, the present invention provides a belt tensioner device, including: an adjustably mountable frame for mounting to a chassis; a pulley fork biasingly mounted to the frame; and a belt pulley mounted between the frame and the fork wherein the frame and fork are co-associated and fabricated of materials each having a complementary CTE to compensate for temperature excursions affecting belt tension.
In another basic aspect, the present invention provides a belt tensioner for an apparatus having a chassis with a belt drive motor affixed thereon for providing translational motion to a belt coupled thereto, wherein the chassis formed of a material having a first CTE, including: first mechanisms for holding a belt pulley axle at a first end, the first mechanisms including mechanisms for fixedly attaching the belt tensioner to the chassis such that the belt is in tension between the belt drive motor and the belt pulley and such that material EC of the first means due to thermal expansion and contraction is diametrically opposed to material EC of the chassis, wherein the first mechanisms are formed of a material having a second CTE and wherein the first CTE and the second CTE are related in proportion to a ratio of a linear distance between the motor and the mechanisms for fixedly attaching the belt tensioner and the distance between the pulley axle and the mechanisms for fixedly attaching the belt tensioner such that EC of each is in substantially identical proportion to the ratio; and a second mechanism for holding the belt pulley axle at a second end, wherein the second mechanism is captured by the first mechanisms and the second mechanism is formed of a material having a third CTE wherein the third CTE is substantially lower than the first CTE and the second CTE such that the second mechanism is substantially unaffected during material EC of the chassis and the second mechanism.
In another basic aspect, the present invention provides an ink-jet printhead scanning carriage drive belt tensioner subsystem for a drive motor and carriage drive belt system, wherein the drive motor is mounted in a first position on a chassis, including: a belt pulley having an axis of rotation; a frame for positioning the belt pulley with respect to the motor, including fastening mechanisms for affixing the frame to the chassis at a second position; and a fork for positioning the belt pulley on the frame such that the belt pulley is between the first position and the second position and the belt is tensioned between the motor and the pulley; the chassis, the frame, and the fork each being fabricated of a material having a differing, compensating, CTE characteristic such that material EC of the chassis and the frame is balanced wherein the axis of rotation remains in a substantially constant position with respect to the first position.
In another basic aspect, the present invention provides a method for maintaining a predetermined tension of a drive belt between a belt drive motor and a belt pulley, including the steps of: affixing the motor to a chassis at a first predetermined position, the mount having a known mount material CTE; affixing the pulley on a frame at a predetermined frame position, the frame having a known frame material CTE; affixing the frame to the chassis at a second predetermined position such that the predetermined tension is established and the pulley is located along a plane between the first predetermined position and the second predetermined position, wherein the length L2 of the frame and the length L3 of the fork is related to the frame material CTE and the fork material CTE, the chassis material CTE and length L1, and the belt CTE and length LBelt, wherein means for affixing the pulley on the frame comprises a material having an affixing means CTE substantially less than the frame material CTE such that substantially no material EC is experienced by the means for affixing during proportional material EC of the mount and the frame.
In another basic aspect, the present invention provides an ink-jet hard copy apparatus, having a scanning carriage for translating at least one ink-jet writing instrument mounted thereon across adjacently positioned print media, including: an apparatus chassis, fabricated of a material having a CTEchassis; a drive motor mounted to the chassis at a first position; a belt pulley mounted on a pulley frame by a pulley fork, wherein the pulley frame is fabricated of a frame material having a CTEframe which is greater than CTEchassis and wherein the pulley fork is fabricated as a fork material having a third CTEfork which is substantially less than the CTEchassis such that there is substantially no center-center change between the motor pulley axis and the turn around pulley axis during thermal excursions wherein the belt material CTE is non-affective as relative to the CTEfork, CTEchassis, CTEframe; and a belt tensioned between the motor and the pulley and having the carriage mounted thereon wherein the pulley frame is affixed to the chassis at a second position with the pulley positioned between the first position and the second position such that a predetermined belt tension is established and maintained regardless of material EC of the chassis and the frame.
In another basic aspect, the present invention provides an ink-jet hard copy apparatus, having a beltriven scanning carriage for translating at least one ink-jet writing instrument mounted thereon across adjacently positioned print media, including: a belt tensioner device, including an adjustably mountable frame for mounting to a chassis, a pulley fork biasingly mounted to the frame, and a belt pulley mounted between the frame and the fork, wherein the frame and fork are co-associated and fabricated of materials each having a complementary CTE to compensate for temperature excursions affecting belt tension.
Some of the advantages of the present invention are:
It maintains a relatively constant belt tension during environmental temperature excursions;
it allows for lower belt tension in a belt drive system, allowing the use of lower cost bush bearings and increasing motor life; and
it provides for increased printer performance at a lower cost.
The foregoing summary and list of advantages is not intended by the inventors to be an inclusive list of all the aspects, objects, advantages and features of the present invention nor should any limitation on the scope of the invention be implied therefrom. This Summary is provided in accordance with the mandate of 37 C.F.R. 1.73 and M.P.E.P. 608.01(d) merely to apprise the public, and more especially those interested in the particular art to which the invention relates, of the nature of the invention in order to be of assistance in aiding ready understanding of the patent in future searches. Other objects, features and advantages of the present invention will become apparent upon consideration of the following explanation and the accompanying drawings, in which like reference designations represent like features throughout the drawings.

Thermal compensation belt drive tensioner


A new cultivar of Berberis plant named ‘Golden Carpet’ that is characterized by a dense prostrate habit and yellow foliage. In combination these traits set ‘Golden Carpet’ apart from all other existing varieties of Berberis known to the inventor.

The present invention relates to a new and distinct cultivar of barberry that is grown as a dwarf shrub for container or landscape. The new cultivar is known botanically as Berberis thunbergii and will be referred to hereinafter by the cultivar name 'Golden Carpet'.
'Golden Carpet' was selected by the inventor in Litomysl, The Czech Republic in 1994, for unique foliage color. The new cultivar 'Golden Carpet' is a hybrid plant that resulted from cross-pollination conducted by the inventor in a cultivated area of Litomysl, The Czech Republic. Cross-pollination was between an individual plant of seed parent Berberis thunbergii 'Aurea' (unpatented) and an individual plant of pollen parent Berberis thunbergii 'Green Carpet' (unpatented).
The new Berberis variety 'Golden Carpet' is a deciduous dwarf shrub characterized by bright yellow foliage. This foliage color continues throughout the summer season when grown in full sun: when grown in partial or full shade, the color of the foliage of 'Golden Carpet' tends to yellow-green or green. The height of the plant is approximately half its width. The foliage color and plant habit distinguish 'Golden Carpet' from all other Berberis known to the inventor.
The new Berberis variety 'Golden Carpet' differs from the yellow foliaged, rounded female parent plant Berberis thunbergii 'Aurea' in that 'Golden Carpet' is prostrate. The new Berberis variety 'Golden Carpet' differs from the light green foliaged male parent plant Berberis thunbergii 'Green Carpet' in that 'Golden Carpet' is bright yellow in color and slightly smaller in size.
The parental cultivars are also the closest varieties of Berberis known to the inventor: 'Aurea' for its foliage color and 'Green Carpet' for its prostrate habit.
The first asexual reproduction of 'Golden Carpet' was conducted by the inventor in 1995 in a cultivated area of Litomysl, The Czech Republic. The method used for asexual propagation was vegetative cuttings. Since that time the inventor has determined that distinguishing characteristics of 'Golden Carpet' are stable and are reproduced true to type in successive generations of asexual reproduction.


A power conversion apparatus is equipped with switching devices to perform power conversion of input AC power supplied from an AC power supply to output AC power having a predetermined voltage and a predetermined frequency, and to supply the power to a motor connected thereto. The apparatus includes a controller controlling switching of the switching devices, a capacitor smoothing a ripple generated by the switching of the switching devices, a current controller controlling a current flowing to the motor, and a voltage distortion corrector detecting a harmonic component caused by distortion in motor input power, and superimposing compensation values on an output of the current controller in accordance with a value of the harmonic component.

Some motors used in an electric compressor etc., of an air conditioning apparatus contain a harmonic component, which is five or seven times the fundamental frequency component, in an induced voltage. In conventional control, an inverter circuit supplying power to a motor is controlled so that the waveform of a phase current flowing to the motor is a sine wave. However, in this control, the motor current may be distorted under the influence of distortion in a motor voltage to cause a torque ripple.
To address this problem, a technique is suggested, which reduces a torque ripple of a motor by preparing a compensation voltage component for cancelling the torque ripple in advance in a table, and adding the compensation voltage to a voltage reference. (See, for example, PATENT DOCUMENT 2.)
On the other hand, in an inverter such as what is called a "capacitorless inverter" (see, e.g., PATENT DOCUMENT 1), which does not include any energy storage element inside, the energy input to the inverter contains a harmonic component when a torque ripple occurs. Then, power-supply harmonic regulations are not satisfied (herein, a power-supply harmonic is a harmonic contained in an input current). To address the problem, a technique is suggested, which reduces current distortion or the torque ripple by controlling the harmonic component of a motor current extra. (See, for example, PATENT DOCUMENT 3.)


A gliding mechanism for a chair or sofa includes a bottom frame having a pair of parallel sides, a pair of swing arms pivotally connected to the interior of the sides near each end thereof defines a parallelogram linkage. A tube connected to and extending beyond the bottom ends of one pair of swing arms pivotally supports a pair of bars at the bottom of a chair or sofa support frame, and a second tube rotatably connected to the other swing arms supports a linkage which also defines part of the chair support frame, whereby the swing arms and support frame glide in unison.

1. Field of the Invention
The invention relates to a rocking and gliding mechanism for a chair or sofa.
2. Discussion of the Prior Art
Rocking and gliding mechanisms for chairs or sofas of the type described herein are disclosed, for example in U.S. Pat. No. 5,427,433, issued to R. E. Holobough Jr. on Jun. 27, 1995; U.S. Pat. No. 5,947,557, issued to P. Bellefleur on Sep. 7, 1999 and U.S. Pat. No. 6,092,870, issued to C. Desnoyers et al on Jul. 25, 2000, and U.S. Patent Application No. 2003/0015900, published on Jan. 23, 2003.
More often than not, currently existing gliding and rocking mechanisms are structurally complicated and/or present stability problems; i.e. the chair or sofas mounted on the mechanisms tend to move laterally as well as forward and backwards during gliding or rocking. Thus, the chairs or sofas do not have a smooth gliding action. Mechanisms including a plurality of linkages in the form of pivotally interconnected bars, strips or sheets of metal are often bulky and expensive to produce.

Support and gliding mechanism for chair or sofa


An electromagnetic valve including a valve housing machine from free cutting steel wherein the housing and the valve""s magnetic core are made from identical, high-alloyed chromium and molybdenum constituents, and wherein the valve housing is fabricated from a chromium-nickel alloy and a high-alloyed chromium-molybdenum compound.

The present invention generally relates to valves and more particularly relates to electromagnetic valves.
German patent application DE 42 21 988 A1 describes an electromagnetic valve which includes a pressure fluid passage between the valve closure member and the valve seat in its electromagnetically non-energized initial position. The valve housing is made from free-cutting steel. Because the selected free-cutting steel is difficult to weld, the sleeve-shaped housing portion which encloses the magnet armature is retained on the magnetic core by means of outside calking of the housing material. Further, the sleeve-shaped housing portion is made of an especially corrosion-resistant, austenitic material which differs from that of the valve housing, in order to reduce the risk of corrosion which is considerable especially in the outside area of the valve by all means.
An object of the present invention is to improve an electromagnetic valve of the type of construction known in the art to such effect that a functionally reliable electromagnetic valve is achieved by simple, low-cost measures, with the valve""s housing lending itself to ease of welding with the sleeve-shaped housing portion. Another objective is to satisfy the demands placed on a high corrosion resistance, very good chip removing capacity, and high mechanical strength of the valve for large-scale series production at minimum possible costs.


A model utilizing cells for assessing oral bioavailability and potential drug-drug interactions of pharmacological agents is described. The model subjects cells (e.g., Caco-2 cells) to conditions that result in reliable expression of catalytically-active CYP3A4 at levels that appear to be comparable to levels present in mature enterocytes. These conditions include plating of selected clones on an extracellular matrix, exposure to 1.alpha.,25-(OH).sub.2 -D.sub.3 for a defined period of time, and the presence of serum in the medium. The model is useful for defining the role of CYP3A4 in limiting the oral bioavailability of many pharmacological agents and in drug-drug interactions involving CYP3A4 substrates that are believed to occur largely at the level of the intestine.

A. Absorption and Bioavailability
Absorption refers to the rate and extent by which a pharmacological agent leaves its site of administration and enters the body. Generally speaking, absorption involves the transfer of the pharmacological agent from the site of administration into the blood stream. The route of administration greatly influences the absorption process. For example, because oral administration frequently involves lipid diffusion of the agent across the lining of the gastrointestinal tract, absorption of orally-administered agents is often dependent on the lipid solubility of the agent. By comparison, pharmacological agents administered intravenously bypass the absorption process because they are introduced directly into the vasculature.
The extent to which a pharmacological agent is absorbed frequently does not correlate with the amount of the agent that is able to exert a pharmacological effect. To illustrate, orally administered agents that are absorbed in the gastrointestinal tract pass through the liver prior to reaching the systemic circulation; as a result, those agents that undergo extensive hepatic metabolism (often referred to as "the first-pass effect") will have a much lower effective concentration when they ultimately reach their site of action. In view of the first-pass effect, clinicians are frequently very interested with the parameter of bioavailability, which refers to the extent to which the agent reaches its site of action (or reaches a biological fluid that provides the agent with access to its site of action) see, e.g., Goodman and Gilman's The Pharmacological Basis of Therapeutics (8th edition, L. S. Goodman, A. Gilman, and A. G. Goodman, eds.) Macmillan Publishing Co. Inc., New York, p. 3-18!.
B. Drug Biotransformation
Enzyme systems involved in the biotransformation (metabolism) of a large proportion of xenobiotics (including many commonly administered pharmacological agents) are primarily located in the endoplasmic reticulum of the liver (termed "the microsomal fraction"). In addition, these enzyme systems are located to a lesser extent in, among other places, the epithelium of the Gastrointestinal tract. The biotransformation reactions caused by these enzyme systems result in the first-pass effect mentioned above.
Two major types of enzymatic biotransformation reactions take place. The first type of reactions (phase-I reactions) transform a xenobiotic into a more polar metabolite, frequently through an oxidative process. Oxidative biotransformation reactions are generally conducted by a family of enzymes termed cytochromes P450. The second type of reactions (phase-II or conjugation reactions) couple the xenobiotic (or its polar metabolite) with an endogenous substrate (e.g., glucuronate) see, e.g., Goodman and Gilman's The Pharmacological Basis of Therapeutics (8th edition, L. S. Goodman, A. Gilman, and A. G. Goodman, eds.) Macmillan Publishing Co. Inc., New York, p. 3-18!.
The major cytochromes P450 that participate in the phase-I biotransformation reactions of xenobiotics can be grouped into three families: i) CYP1, ii) CYP2, and iii) CYP3. Enzymes within the CYP3A subfamily are found in hepatocytes and small intestinal epithelial cells (enterocytes) and are extensively involved in phase-I biotransformation reactions.
CYP3A4 is the principal cytochrome P450 present in human liver T. Shimada and F. P. Guengerich, Proc. Natl. Acad. Sci. U.S.A. 86:462-465 (1989)! and enterocytes P. B. Watkins et al., J. Clin. Invest. 80(4):1029-1036 (1987)!. Intestinal CYP3A4 has been implicated in the metabolic elimination of many drugs F. P. Guengerich, Toxicol. Lett. 70:133-138 (1994)!, and first-pass metabolism by the enzyme is believed to contribute to the poor oral bioavailability of some of these drugs see, e.g., J. C. Kolars et al., Lancet 338:1488-1490 (1991); M. F. Paine et al., Clin. Pharmacol. Ther. 60:14-24 (1996)!.
C. In Vitro Models for Studying Oral Bioavailability and Drug Interactions
In vitro studies have previously been performed with the human colon carcinoma cell line Caco-2 see, e.g., M. Pinto et al., Biol. Cell 47:323-330 (1983)! to study oral bioavailability. When grown as monolayers on permeable supports, Caco-2 cells have proven useful as a model for studying intestinal permeability I. J. Hidalgo et al., Gastroenterology 96:736-749 (1989)! and several transport functions, including the transport of bile acids, large neutral amino acids, and some drugs see, e.g., J. Karlsson et al., Br. J. Pharmacol. 110:1009-1016 (1993); D. T. Thwaites et al., Br. J. Pharmacol. 114:981-986 (1995)!.
However, the Caco-2 cell line has thus far fallen short as an ideal model for predicting oral bioavailability or studying drug-drug interactions. For example, cultures of the Caco-2 cell line were capable of metabolizing cyclosporin A to one of the major metabolites, but two other metabolites of cyclosporin A were not detected L.-S. L. Gan et al., Drug Metab. Dispos. 24:344-349 (1996)!. Moreover, the rate of nifedipine oxidation has also been reported to be low in Caco-2 cells X. Boulenc et al., J. Pharmacol. Exp. Ther. 263:1471-1478 (1992)!.
In view of the shortcomings of present models, what is needed is an in vitro model, associated with reproducible results, for accurately predicting bioavailability of pharmacological agents and for studying drug-drug interactions.

Cell culture model for drug bioavailability

The Regents of the University of Michigan


A surface protection film comprising a transparent backing of polypropylene or propylene-ethylene copolymer, which comprises a light stabilizer, and a self-adhesive composition of polyethylene-vinyl acetate (EVA) having a VA fraction of from 40 to 80% by weight and a melt index MFI in accordance with ISO 1133 (A/4) of from 0.5 to 25 g/10 min at 190xc2x0 C. and 2.16 kg, which is blended with from 0 to 35% by weight of a polyether of the form

The invention relates to a protective film whose high transparency and reliable adhesion make it particularly suitable for the temporary protection of automobile glass and also other sensitive surfaces such as metals, plastics and surface coatings.
On the long journey traveled by export vehicles in particular from the manufacturing plant to the end user, starting with the assembly of the vehicle and continuing by way of its loading onto railcars, transportation by rail or road, unloading from the railcar, loading onto ships, the ship journey, unloading from the ship, transportation to the central storage facility, and transportation through to the local dealer, the new vehicle is exposed to diverse harmful influences. Repairs to paint and windows, especially the windshield, are the order of the day, since the customer demands a flawless new vehicle. This is a considerable cost factor for the manufacturers, and there is a great interest in reducing this expense.
Whereas minor paint damage can generally be removed by means of a small refinish, making good a scratch on an automobile window necessitates its complete replacement.
The replacement of a windshield is particularly expensive. In the case of a windshield installed by bonding with a water-reactive PU adhesive, the technique now used almost universally, the windshield is removed using a wire which cuts through the adhesive film. In the course of this operation, the windshield frame paint is often damaged, necessitating additional repairs. For the manufacturer, accordingly, there arise costs for the replacement windshield, for its removal and installation, and, possibly, for the repair of the paint damage caused during its replacement. In some cases, additionally, the delivery times are prolonged significantly, and customers are unhappy.
For a number of years already, paint surfaces of new vehicles, especially exposed surfaces, such as trunk lids, roof and engine hood, in particular, have been effectively masked off using self-adhesive films. They protect the finishes against slight injuries and soiling by media such as battery acid or fuel, fly rust and bird excrement. These films generally comprise unoriented polyolefin films of polyethylene, polypropylene or propylene-ethylene copolymers, and also mixtures of these, filled with TiO2 to improve the long-term stability. The adhesive composition used frequently comprises polyisobutylene or polyethylene-vinyl acetate.
The former are disclosed in EP 0 519 278 A2, where the adhesive composition is applied to a film which in turn is used to protect automobiles. The pressure-sensitive adhesive is based on polyisobutylene rubber, having a dynamic modulus of elasticity of from 2xc3x97105 to 7xc3x97106 dyn/cm2, corresponding in SI units to a figure of from 2xc3x97104 to 70xc3x97104 Pa, at 60xc2x0 C. In addition, the adhesive may have been blended with a silicone oil or with a low molecular mass acrylic polymer.
DE 196 35 704 A1 describes a self-adhesive surface protection film made from polyolefins with an adhesive comprising polyethylene-vinyl acetate (EVA) with a vinyl acetate content of from 40 to 80 mol %, especially 70 mol %, and with a loss angle tan xcex4 of from 0.6 to 1.0, measured at a temperature of 60xc2x0 C. and a frequency of 10xe2x88x922 Hz, and from 0.4 to 0.7, measured at a temperature of 60xc2x0 C. and a frequency of 10 Hz. EVA in the claimed form possesses good initial bond strength to paint and good paint compatibility. The high ultimate bond strength to paints and glass surfaces, although it permits highly reliable bonding, nevertheless necessitates a disproportionately great effort when removing the film, which may adversely affect the health of persons for whom the demasking is a daily task. Moreover, because of the high bond strength, tearing during the demasking operation is a frequent occurrence, and means that the film cannot be removed in one piece.
Those nontransparent, white films specified in the prior art, however, cannot be used for window protection, since the masked vehicles must be moved and arranged a number of times in the course of their distribution, and an unobstructed view through the windows is vital.
There have been numerous descriptions of window films, which alter the properties of the windows to which they are stuckxe2x80x94they do this, for example, by darkening shading, IR absorption for heat insulation, or as antireflection coatings. U.S. Pat. No. 5,925,453, for example, describes a window film which is light-reflecting and IR-absorbing and can be stuck to the inside of curved auto windows. Preferred candidates as backing materials, which may also be blended with the IR absorbent, include polyolefins such as polyethylene and polypropylene, polyvinyl chloride and polyesters such as polyethylene terephthalate and polybutylene terephthalate. Possible adhesive compositions cited are self-adhesive compositions, including synthetic rubbers such as styrene-butadiene rubber, polyisobutylene, styrene block copolymers and polyethylene-vinyl acetate, and also heat- and moisture-activable compositions. The film described, however, has no protective function, especially since it is applied from the inside to the concave glass surfaces. Articles of this kind are normally conceived for permanent bonding and must therefore meet different key requirements.
In the case of a protective film for automobile glass, particular value must be placed not only on outstanding transparency but also on easy, fold-free and rapid applicability and on a balanced bond strengthxe2x80x94i.e., a bond strength which is not so weak that the film is detached under the influence of wind or slipstream, or even detaches by itself, but also not so strong that it is impossible to remove the film again without excessive effort or even tearing. Moreover, the film must withstand outdoor weathering periods, typical for its application, of approximately 6 months without becoming brittle, becoming dull, or leaving residues of adhesive composition on removal. The abovementioned requirements place stringent demands on film and adhesive composition and on the tailoring of the two components to one another.
Beiersdorf A G, Hamburg, Germany, has for many years sold as Article 4604 PV1 a transparent protective film which is used, inter alia, for window protection but which in many respects does not meet customer requirements of transparency, weathering stability and bonding reliability for this utility. The aforementioned article comprises a polyethylene backing and is coated with an acrylate self-adhesive composition. The film is slightly cloudy, which manifests itself as highly disruptive especially when light is incident from the sides. After a few weeks or outdoor weathering, the film becomes brittle under the effect of UV light, so that it can no longer be removed in one piece and the adhesive composition remains extensively on the glass. Furthermore, the film loses its adhesion properties at temperatures above 60xc2x0 C., which are easily achieved under insolation, whereupon shrinkage-related folds are produced.
It is an object of the invention to provide a surface protection film for automobile glass, especially windshields, and other sensitive surfaces which does not exhibit the above-described disadvantages of the prior art, or not to the same extent. In particular, the surface protection film should possess not only a pronounced initial bond strength but also a balanced ultimate bond strength and an extremely high transparency, and also weathering stability.
This object is achieved by means of a surface protection film as laid down in the main claim. The subclaims relate to advantageous developments of the surface protection film.
The invention accordingly provides the construction of a surface protection film comprising a transparent backing of polypropylene or propylene-ethylene copolymer, which comprises a light stabilizer, and a self-adhesive composition of polyethylene-vinyl acetate (EVA) having a VA fraction of from 40 to 80% by weight and a melt index MFI in accordance with ISO 1133 (A/4) of from 0.5 to 25 g/10 min at 190xc2x0 C. and 2.16 kg, which is blended with from 0 to 35% by weight of a polyether of the form
XOxe2x80x94[(CH2)4xe2x80x94O]xe2x80x94Yxe2x80x83xe2x80x83(1)
or
xe2x80x83XOxe2x80x94[(CH(CH3)xe2x80x94CH2xe2x80x94O]xe2x80x94Yxe2x80x83xe2x80x83(2),
having a weight-average molecular weight Mw of from 200 to 100,000 g/mol, X and Y being selected from the group consisting of Hxe2x80x94, (CnH2n+1)xe2x80x94 where n is from 1 to 20, CH2xe2x95x90CHCOxe2x80x94, CH3CH(NH2)CH2xe2x80x94, 2,3-epoxypropyl-, C6H5xe2x80x94COxe2x80x94, CH2xe2x95x90C(CH3)xe2x80x94COxe2x80x94.
In one preferred embodiment, the surface protection film comprises an unoriented film of from 30 to 120 xcexcm in thickness, preferably from 35 to 80 xcexcm in thickness, comprising a random propylene-ethylene copolymer having an ethylene fraction of from 2 to 10% by weight, preferably from 4 to 8% by weight, and more than 0.3% by weight, preferably more than 0.5% by weight, of a light stabilizer.
The adhesive composition comprises polyethylene-vinyl acetate having a VA fraction of from 40 to 80% by weight, preferably from 45 to 70% by weight, and an addition of (1) or (2) of from 0 to 35% by weight, preferably from 0 to 20% by weight, applied preferably at a rate of from 8 to 50 g/m2, with particular preference from 10 to 30 g/m2.
Between adhesive composition and film there may be a primer comprising EVA having a VA fraction of from 20 to 50% by weight, preferably from 25 to 40% by weight, in a thickness in particular of from 5 to 20 xcexcm, preferably from 5 to 15 xcexcm, which is coextruded with the backing layer. In this preferred form, the film is wound up in its final form directly after coating. The proposed primer possesses outstanding transparency, both alone and in conjunction with the film.
The use of the claimed propylene-ethylene copolymers combines a surface smoothness and transparency that is outstandingly suitable for this utility with great flexibility, so that bonding can take place without folds even to curved surfaces. The mechanical and optical properties of the film are significantly affected not only by the selection of raw materials but also by the production conditions. An advantageous process for the desired properties is the casting process, where the temperature of the chill rolls should be between 10 and 25xc2x0 C. in order to permit extremely fine crystallization.
Under application conditions, the transparency is retained, even after using the windshield wipers and after 6 months in a Florida climate, to such a degree that the vehicle can still be removed without hazard.
Particularly suitable means of ensuring a long life of the film material, in a manner compatible with the application, are HALS light stabilizers such as, for example, dimethyl succinate polymer with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoethanol (CAS No. 65447-77-0), bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate (CAS No. 52829-07-9) or poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][[(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino]] (CAS No. 70624-18-9).
The claimed adhesive composition based on EVA, with and without polyether addition, is highly suitable for glass surfaces, since it possesses the property of flowing out flush with glass and of producing a virtually invisible phase boundary between glass and composition. The EVA in the form described forms the polymer framework of the adhesive composition, with a moderately pronounced tack and a rapidly increasing bond strength thereon, which attains its ultimate value within a few days, this value being achieved more quickly under the action of heat.
Since the polymer framework in question is chemically uncrosslinked, and on the basis of its monomer proportion is only very slightly crystalline, the molecular weight, which correlates directly to the MFI, adopts a decisive position in respect of the cohesiveness of the adhesive composition. An MFI of from 1 to 5 has proven to be a favorable value. The addition of an EVA fraction having an MFI of up to 25, however, may contribute to improving the flow properties if the adhesive composition is to be applied from the melt or coextruded together with a backing.
The optional addition of the polyethers described has the effect of reducing bond strength at the same time as maintaining the required initial tack, the aging stability, the transparency, the health and environmental acceptability, and the freedom of the overstuck glass surfaces from deposits after demasking, if the ultimate bond strength of the adhesive film is perceived to be too high. The unwind behavior of the protective films, wound up into rolls, may also be reduced by the addition of the above-described polyethers, relative to the straight EVA composition. Depending on the fraction of the added polyether, the bond strength reducing effect may be regulated steplessly.
The adhesive composition may be processed either from solution or from the melt, i.e., as a hot-melt, or by coextrusion. From 10 to 30 g/m2 is an advantageous application rate. It ensures a sufficient cushion of composition for said composition to flow out flush with the surface, without there being any notable residues of composition.
For the very high optical requirements imposed on a protective film for windows, or glass generally, fields of use for which the surface protection film of the invention is particularly suitable, it is absolutely necessary, directly after coating, to roll up the film in its final form without folds or bubbles. Subsequent rewinding is highly deleterious to the optical properties, since folds and bubbles impress themselves irreversibly into the film of adhesive composition. Even intermediate release media such as siliconized paper are unsuitable, since the always slightly rough structure is impressed into the cushion of adhesive composition and causes the product to become matt.
The surface protection film of the invention for automobile glass windows in particular is described below in a preferred embodiment on the basis of a number of examples of surface protection films, without wishing thereby to restrict the invention in any way whatsoever. Also given are two comparative examples featuring unsuitable surface protection films.

Self-adhesive highly transparent protective article for automobile windows and other sensitive surfaces

Abstract: or

Abstract: having a weight-average molecular weight Mw of from 200 to 100,000 g/mol, X and Y being selected from the group consisting of Hxe2x80x94, (CnH2n+1)xe2x80x94 where n is from 1 to 20, CH2xe2x95x90CHCOxe2x80x94, CH3CH(NH2)CH2xe2x80x94, 2,3-epoxypropyl- or C6H5xe2x80x94COxe2x80x94, CH2xe2x95x90C(CH3)xe2x80x94COxe2x80x94.


A bottle holder for restrictively holding two bottles in prescribed positions, comprising a base, a top member, and a side wall, the bottles being mounted between the base and top member. The holder is improved in that there are provided a rail and groove sliding fit of the top member and side wall, and an interlock fit wherein a tooth on one of the top member and side wall slides over a ledge until it fits under the ledge in a locking manner to prevent disassembly.

In an automated analyzer using liquid reagents in a reaction cuvette to assay for an analyte in a patient sample liquid, it is conventional to supply the different reagents from a plurality of different bottles held in a bottle holder. An example is shown in U.S. Pat. No. 5,075,082. In such a holder, it is important that each bottle be kept at its prescribed position and that the user not be able to re-position (i.e., switch) the bottles, either deliberately or by accident, lest the analyzer withdraw the wrong reagent from a given position in the holder. Such bottle position integrity is maintained by the construction shown in said '082 patent by reason of a) the size differences between the bottles and the construction of the holder to receive only those sizes, and b) the use of welding (column 4, lines 14-19) to integrate the holder so that it cannot be later reopened and the bottles re-positioned.
However, it is preferred that identical bottle sizes be available, rather than distinguishing positions in the holder solely by bottle size. This allows for bottle interchangeability, when filling the bottles during manufacturing. Further, a construction that requires the parts to be welded together to prevent bottle re-positioning, is obviously more expensive than a construction assembled simply by sliding parts together. However, any assembly by sliding can be undone by reversing the sliding, thus making it easy for a user to re-position the bottles.
Therefore, there has been a need prior to this invention to provide a bottle holder for use as described, which is more readily assembled than is possible by welding, and yet ensures substantial permanence in the assembly to prevent bottle re-positioning.


A micro-electromechanical system (MEMS) current and magnetic field sensor for sensing a magnetic field produced by a conductor includes a magneto-MEMS component for sensing the magnetic field and an interference-MEMS component for sensing an interference, wherein the magneto-MEMS component and the interference MEMS component are used to provide an indication of the current in the conductor.

The present disclosure relates generally to electrical current and magnetic field sensing devices. More particularly, the present disclosure relates to a micro-electromechanical system (MEMS)-based current and magnetic field sensor.
A current carrying conductor produces a magnetic field in the vicinity of the current carrying conductor. The magnetic field produced by the current carrying conductor can induce a force on another current carrying conductor disposed in the magnetic field produced by that current carrying conductor. As such, one approach used to sense electrical current involves the use of a sensor that measures the magnetic field induced by current flowing in a current carrying conductor. Since the generated magnetic field is proportional to the current flowing in the current carrying conductor, such a sensor can use the magnitude of the magnetic field to determine the current.
From a safety perspective, current sensors that use magnetic fields to measure electrical current are well suited for high voltage applications because they do not have to contact the high voltage circuitry. However, there are several disadvantages associated with existing current sensors that use magnetic fields to measure electrical current in high voltage applications. For example, existing current sensors tend to have a large form factor because they require a thick conductor that can withstand the varying levels of current flow that can be experienced. Additionally, the current flow induces heating, which reduces the efficiency and accuracy of the current sensors. Since existing current sensors are large and bulky, their physical and electrical operating characteristics have prevented their use in smaller scale environments.
Recently, micro-electromechanical systems have been utilized as current sensors. However, many of theses micro-electromechanical system current sensors are susceptible to environmental factors that impact their accuracy.
There accordingly remains a need in the art for a MEMS-based magnetic filed sensor capable of producing accurate readings in an environment that includes interference.

Micro-electromechanical system (MEMS) based current and magnetic field sensor


A device is disclosed for adjusting the tension of the strings of a string instrument, especially a guitar, preferably an electric guitar, or a bass, preferably an electric bass, said strings being secured at a first end to a winding mechanism and at a second end to another mount, said device having at least one motor, a gear connected to the motor and flexible shafts connected to the gear for transmission of a rotational movement generated by the combination of the motor and the gear to the winding mechanism whereby the device has fewer motors than there are strings on the string instrument.

The present invention relates to a device for adjusting the tension of strings of a string instrument, said strings being attached at a first end to a winding device and at a second end to another mount, the string instrument being in particular a guitar, preferably an electric guitar or a bass, preferably an electric bass.
For correct tuning of string instruments, it is necessary to accurately adjust the tension of the strings stretched between two mounting points on these instruments, so that when a string is struck, a standing wave of the correct frequency develops, thereby creating the desired note.
The strings of a string instrument are usually rigidly attached at one of their two ends, the second end of the string being coiled onto a winding device, e.g., in the form of a spindle or a similar element so that it can be tightened and relaxed by winding and unwinding to thereby achieve the correct tuning of the string.
In particular, when the string instrument is also to be automatically tunable, i.e., by means of a control mechanism that controls a drive to change the string tension on the basis of the actual note picked up from the string that is struck in a comparison of same with an ideal note, so that the string produces the ideal note, the tension of the strings must be adjustable automatically. It has therefore already been proposed elsewhere that each of the winding devices should be provided with its own motor drive.
In the case of a guitar, for example, in particular an electric guitar, and/or a bass, preferably an electric bass, the so-called tuning mechanisms, i.e., the pegs for tightening and relaxing the strings are situated on the so-called head of the instrument and thus on a comparatively small part of the instrument. In principle, motor drives could be mounted here for adjusting the string tensions of the individual strings, but it is very difficult to accommodate all these components on the head of the guitar, where space is very limited, without having a negative effect on its appearance and handling. It is then almost impossible to arrange the entire control for a system for automatic tuning of a guitar and/or a bass, preferably an electric bass, on this part of the instrument in addition to the drives. To this extent, it is desirable to search for alternative options for adjusting the tension of a string of a string instrument.

Device for adjusting the tension of the strings of a stringed instrument

Abstract: With this device it is possible to arrange a drive for automatic adjustment of the tension of the strings of the string instrument in a space-saving manner and in the smallest possible amount of space.


An image processing method for a liquid crystal display device includes: calculating first difference gradation, which is a difference between predicted attainment gradation and input gradation, the predicted attainment gradation being a predicted value of gradation which respective pixels of the liquid crystal display attain after one frame period after the respective pixels are driven to display a first frame, and the predicted attainment gradation being stored in a storage unit which stores the predicted attainment gradation, and the input gradation being gradation of a second frame which is displayed after the first frame; multiplying the first difference gradation by an enhancement coefficient; calculating enhanced gradation which is a sum of the first difference gradation multiplied by the enhancement coefficient and the predicted attainment gradation; calculating second difference gradation which is a difference between the enhanced gradation and the predicted attainment gradation; multiplying the second difference gradation by a correction coefficient; and updating the value of the predicted attainment gradation stored in the storage unit based on a sum of the second difference gradation multiplied by the correction coefficient and the predicted attainment gradation.

1. Field of the Invention
The present invention relates to an image processing apparatus that processes a moving image to be displayed on a liquid crystal display device, an image processing method and an image processing program.
2. Description of the Related Art
In recent years, liquid crystal display devices are used in many fields such as monitors for Personal Computer (PC), notebook PC, and television, and accordingly providing more opportunity to view moving images on liquid crystal display devices. Since, however, the response time of liquid crystal in the liquid crystal display devices is not fast enough, when a moving image is displayed, the deterioration of image quality such as blur and persistence of vision occurs. In general, since the refresh rate of the liquid crystal display devices is 60 Hz, a target response time is 16.7 ms or less in the display of moving images.
In order to improve the response time of the liquid crystal display devices, new liquid crystal materials with short response time are developed, and a method of driving the liquid crystal display devices using conventional liquid crystal materials is improved. As new liquid crystal display materials, smectic type ferroelectric crystal, antiferroelectric crystal and the like are developed, but they have a lot of problems, such as ghosting due to an influence of spontaneous polarization of liquid crystal materials and easy breakage of an orientation state in liquid crystal due to pressure or the like, which have to be solved.
On the other hand, as methods of driving liquid crystal display devices using conventional liquid crystal materials are improved, a method of writing to the liquid crystal display devices a gradation (enhanced gradation) to which predetermined gradation is added according to writing gradation when displayed gradation changes is proposed (for example, see Japanese Patent Application Laid-Open No. 2003-264846: Hereinafter, called as the first document) as a method of improving the response time of the liquid crystal display devices. According to the method in the first document, since the enhanced gradation is obtained by a comparatively simple calculation, a high-speed process can be executed by software.
The method in the first document, however, has a problem that an improving effect of the response time is insufficient between some gradations. For example, in a change from 0 gradation to 255 gradation, since the gradation of image data is generally 255 (8 bit) at the highest, the writing gradation cannot be enhanced. For this reason, the enhanced gradation is also 255, but in this case the response cannot be completed after one frame. In the structure proposed in the first document, when the device needs to obtain enhanced gradation of a next frame, the device calculates the enhanced gradation of the next frame assuming that the current frame has already attained 255, and thus distortion of the response waveform such as undershoot occurs. Such distortion of the response waveform in the liquid crystal display devices is visually recognized as a deterioration of moving images displayed on the liquid crystal display device.
The present invention is devised in order to solve the above problems and its main object is to provide an image processing apparatus, an image processing method, and an image processing program which reduce distortion of a response waveform of a moving image to be displayed on a liquid crystal display device by comparatively simple calculation and is capable of improving image quality.

Image processing apparatus for processing moving image to be displayed on liquid crystal display device, image processing method and computer program product


A reflector lamp or illumination system comprising a concave reflector having a parabolic or ellipsoidal front section and a spherical rear section with it's focal point just ahead of the focal point of the front section, and a finite light source located at the focal point of the front section. The reflector sections are dimensioned so that light rays from the finite light source which are reflected by the spherical rear section become re-reflected by the front section and distributed more evenly in said projected beam pattern with the energy rays filling back in from the edge to the center. Additionally the light rays, re-reflected by the front section, are made up of uncompressed light and energy components which provide a beam pattern which is substantially more even in light and energy distribution, does not have compressed light and energy producing hot spots of light and heat at the center of the projected beam pattern or gate, and is therefore less harmful to parts such as lighting fixture parts, plastic lens and items being projected such as plastic color media, film, and slides.

Light reflectors have long been used to bounce light off of a reflective surface. Light generally shines in all directions from a light source. However, if light shining in all directions from a light source is not useful, a reflective surface can be employed to reflect light towards a direction in which the light is useful. In this way, light reflectors increase the efficiency of a lamp or light source.
One general type of reflector comprises a concave reflector having a parabolic contour with respect to a focal point, so as to reflect frontwardly and along the lamp axis light emitted by a light source located at and near the focal point. The cross section of the reflector, perpendicular to the lamp axis, usually is circular with the diameter thereof varying with the distance from the focal point.
Another general type of reflector comprises a concave reflector having an ellipsoidal contour with respect to a focal point, so as to reflect frontwardly and along the lamp axis light emitted by a light source located at and near one of the ellipsoidal focal points to the second ellipsoidal focal point located frontwardly and determined by the size of the geometric ellipsoidal contour. The light leaving the ellipsoidal reflector usually passes through a gate and then enters into a series of lenses to more accurately control dispersion of the projected beam of light. The cross section of the reflector, perpendicular to the lamp axis, usually is circular with the diameter thereof varying with the distance from the focal point.
Additionally, a cone of light rays, originating from the light source, pass, unreflected, through the front of the reflector; the angle of this cone of rays being determined and defined by the front rim of the reflector. The more widely divergent light rays of the cone of rays, that is, the rays passing relatively nearer to the rim of the reflector, have such a large sideways component of direction so as to fall outside of the desired light pattern or gate and therefore are wasted.
The wasted, divergent light can be reduced, and the optical efficiency improved, by making the reflector deeper, that is longer, so that relatively more of the light is reflected in the desired direction and the cone of non reflected light is narrowed. However, there are practical limitations on increasing the depth of the reflector, such as cost, weight and awkwardness of use. Also, with a given maximum diameter as the reflector is made deeper, the focal point moves closer to the rear surface, which complicates positioning of the light source in reflector systems and if the light source is a filament inside a reflector lamp there is accelerated blackening of the nearby rear area of the reflector due to evaporation of the filament material (usually tungsten). This accelerated blackening in the reflector lamp can be alleviated by providing a concave recess at the rear portion of the reflector but has the drawback of reducing optical efficiency. In a reflector or reflector system, as the focal point moves closer to the rear surface, the percentage of reflected energy from the finite light source is compressed and packed much more tightly toward the center of the reflector and, as a result, the opening for the finite light source will remove an area of the reflector that would normally reflect a larger percentage of the light being generated than if it were a shallow reflector, thus reducing optical efficiency of the deep reflector system.
Additionally, it has now been found that as the parabolic or ellipsoidal contour of the reflector is made deeper and the focal point is moved closer to the rear of the reflector, the reflected light and heat from the light source is packed more tightly and reflected in a compressed narrower band at the center of the projected beam pattern or gate. This increase in light and heat energy is increased logarithmically as the reflector depth is increased in relation to the same width. This causes uneven projected beam patterns with concentrated areas know as hot spots in a parabolic reflector system or hot spots and uneven coverage of light causing shadows in the gate of an ellipsoidal reflector system. These compressed areas also concentrate heat at the center of the projected beam that can be very detrimental to parts of the illumination system and accessories used with these systems such as, but not limited to, color gel material, gobos, plastic lens, projection slides, and film used in motion picture projectors.

Heat distributing hybrid reflector lamp or illumination system