The disclosure includes an outer electrode and an inner electrode. The outer electrode defines an inner volume and is configured to receive injected electrons through at least one aperture. The inner electrode positioned in the inner volume. The outer electrode and inner electrode are configured to confine the received electrons in orbits around the inner electrode in response to an electric potential between the outer electrode and the inner electrode. The apparatus does not include a component configured to generate an electron-confining magnetic field.

Sputter ion pumps are vacuum pumps designed to remove ions from a gas medium using sputtering. As one example, a sputter ion pump may be fluidically coupled to a vacuum chamber. The sputter ion pump utilizes a strong electrical potential between an anode and a cathode to emit electrons from a cathode of the ion pump. The emitted electrons cause impact ionization of background gas species, which are field-accelerated by the electric potential, driving these ions into the cathode and removing the ions from the gas medium to create the vacuum. Sputter ion pumps typically use a magnetic field to confine electrons within the ion pump.


A multi-layer display system for displaying 3D images with reduced saccadic breakup includes a plurality of display screens arranged in a substantially parallel and overlapping manner, and a processing system. The processing system is configured to minimize or prevent saccadic breakup of displayed images by detecting head and/or eye movement of a viewer, and accordingly controlling color saturation of display fields when movement of head and/or eye is detected.

This disclosure relates generally to displays and, more particularly, to display systems and methods for displaying images on multi-layer displays.
Image displays limited to a single two dimensional display lack depth information. That is, such displays do not relay depth information in the image to the viewer. To relay depth information of objects, there have been efforts to provide displays that can display the objects in three-dimensions. For example, stereo displays convey depth information by displaying offset images that are displayed separately to the left eye and the right eye. However, stereo displays are limited as to what angle an observer can view the display. In addition, stereo displays may cause various discomforting symptoms, such as eye strain, blurred vision, and double vision.
Multi-layer displays have been developed to display objects with a realistic perception of depth. Multi-layer display (MLD) systems are becoming popular for several applications such as, for example, vehicle dashboards, game machines, handheld devices and the like. MLD systems can be configured to display images of scenes so that depth can be represented by distributing objects to be displayed on to the separate display panels of the MLD. Example MLD systems are described in U.S. patent application Ser. No. 15/359,732 filed on Nov. 23, 2016, the contents of which is incorporated herein in its entirety.
In some display techniques, such as in field sequential display, in order to display an image, the eye would be presented with red, green and blue images in rapid succession time sequence. When the viewer is stationary, the red, green and blue images of the same image, all impose at the same position of the retina, and the viewer sees the intended image in the intended color. However, saccadic breakup, which manifests as small images of the red, green and blue fields shown on the retina when the viewer's head moves, ruins or degrades the viewing experience in some instances and may produce color fringes etc.

Head tracking based field sequential saccadic break up reduction


An aqueous ink jet ink is disclosed which comprises an effective amount of an azomethine dye having at least one water solubilizing functional group covalently attached thereto. The water solubilizing functional group can either be directly attached to the azomethine dye and/or can be attached to the azomethine dye through an electrophilic coupling moiety. If an organic spacer group is used to separate the water solubilizing functional group from azomethine dye or the electrophilic coupling moiety, then straight and branched chained alkyl groups having from about 1 to 10 carbon atoms is preferred. Preferred azomethine dyes can be pyrazolone azomethines, pyrazolotriazole azomethines, and combinations thereof. Additionally, an aqueous ink jet ink is disclosed comprising an effective amount of a dye-based colorant and an essentially water soluble spiroindane additive for improving light fastness and stability of the dye-based colorant.

The present invention is drawn to dye-based ink jet ink compositions having improved stability and light fastness.
In recent years, computer printer technology has evolved to a point where very high resolution images can be transferred to various types of media, including paper. One particular type of printing involves the placement of small drops of a fluid ink onto a media surface in response to a digital signal. Typically, the fluid ink is placed or jetted onto the surface without physical contact between the printing device and the surface. Within this general technique, the specific method that the ink jet ink is deposited onto the printing surface varies from system to system, and can include continuous ink deposit and drop-on-demand ink deposit.
With regard to continuous printing systems, inks used are typically based on solvents such as methyl ethyl ketone and ethanol. Essentially, continuous printing systems function as a stream of ink droplets ejected and directed by a printer nozzle. The ink droplets are directed additionally with the assistance of an electrostatic charging device in close proximity to the nozzle. If the ink is not used on the desired printing surface, the ink is recycled for later use. With regard to drop-on-demand printing systems, the ink jet inks are typically based upon water and glycols. Essentially, with these systems, ink droplets are propelled from a nozzle by heat or by a pressure wave such that all of the ink droplets ejected are used to form the printed image.
There are several reasons that ink jet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of these reasons include low printer noise, capability of high speed recording, and multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. However, though there has been great improvement in ink jet printing, accompanying this improvement are increased demands by consumers in this area, e.g., higher speeds, higher resolution, full color image formation, increased stability, etc. As new ink jet inks are developed, there have been several traditional characteristics to consider when evaluating the ink in conjunction with a printing surface or substrate. Such characteristics include edge acuity and optical density of the image on the surface, dry time of the ink on the substrate, adhesion to the substrate, lack of deviation of ink droplets, presence of all dots, resistance of the ink after drying to water and other solvents, long term storage stability, and long term reliability without corrosion or nozzle clogging. Though the above list of characteristics provides a worthy goal to achieve, there are difficulties associated with satisfying all of the above characteristics. Often, the inclusion of an ink component meant to satisfy one of the above characteristics can prevent another characteristic from being met. Thus, most commercial inks for use in ink jet printers represent a compromise in an attempt to achieve at least an adequate response in meeting all of the above listed requirements.
In general, ink jet inks are either dye- or pigment-based inks. Dye-based ink jet inks generally use a liquid colorant that is usually water-based to turn the media a specific color. Because of their makeup, dye-based inks are usually not waterproof and tend to be more affected by UV light. This results in the color changing over time, or fading. For optimum performance, this type of ink has often required that the proper media be selected in accordance with the application, thus, reducing the choice of media for printing. Conversely, pigmented inks typically use a solid colorant to achieve color. In many cases, the line quality and accuracy of plots produced by pigment-based inks are usually superior to that of dye-based inks. With pigmented inks, solid particles adhere to the surface of the substrate. Once the water in the solution has evaporated, the particles will generally not go back into solution, and are therefore more waterproof. In addition, pigmented inks are much more UV resistant than dye-based inks, meaning that it takes much longer for noticeable fading to occur. Though pigmented inks, in some areas, exhibit superior characteristics, dyes tend to run cleaner, provide better yield, offer better particle size, and are easier to filter. Thus, dye-based inks have been more often used for common applications and have tended to be more chromatic and provide more highly saturated colors.
In order for ink jet prints to effectively compete with silver halide photography, one important improvement that must occur is that ink jet inks must improve their ability to remain stable to light exposure for longer periods of time. At this point in time, photographs typically will last much longer under prolonged light exposure, i.e., about 14-18 years under fluorescent light exposure. Conversely, some of the best ink jet printers will produce prints that last for only about 6-8 years under similar conditions. Particularly, with respect to dye-based ink jet ink, the phenomenon of discoloration occurs even more readily than is typical for pigment-based ink jet inks. However, as described above, dye-based inks are sometimes preferred because they are very convenient to use and have good distinction of color.
In the photographic industry, technologies have been developed which have been reported to last much longer than the typical 14-18 years, and even up to 60 years. Such long lasting ink stability has been attributed to a very stable magenta dye which is, in part, the subject of U.S. Pat. No. 5,242,785. That patent reports many new dyes and additives that have very good light fastness (2% dye loss after 16.5 years of simulated light exposure). However, though these dyes are very stable under prolonged light exposure, these dyes are not water-soluble and contain long chain organic groups necessary for anchoring dyes in photographic media. Such structures are not useable in aqueous-based ink jet systems.
Thus, it would be useful to provide aqueous ink jet inks for printing on media such that the inks are more stable under prolonged light exposure and/or exhibit good light fastness. This can be accomplished by providing dyes and/or additives for aqueous ink jet inks that improve these and other important properties.
An aqueous ink jet ink is disclosed which comprises an effective amount of an azomethine dye having at least one water solubilizing functional group covalently attached thereto wherein the water solubilizing functional group is directly attached to the azomethine dye or is attached to the azomethine dye through an electrophilic coupling moiety. If an organic spacer group is used to separate the water solubilizing functional group from azomethine dye or the electrophilic coupling moiety, then straight and branched chained alkyl linkers or spacers having from about 1 to 10 carbon atoms are preferred. Preferred azomethine dyes can be pyrazolone azomethines, pyrazolotriazole azomethines, and combinations thereof. Additionally, an aqueous ink jet ink is disclosed comprising an effective amount of a dye-based colorant and an essentially water soluble spiroindane additive for improving light fastness and stability of various dye-based colorants.
Before the present invention is disclosed and described, it is to be understood that this invention is not limited to the particular process steps and materials disclosed herein because such process steps and materials may vary somewhat. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only. The terms are not intended to be limiting because the scope of the present invention is intended to be limited only by the appended claims and equivalents thereof.
It must be noted that, as used in this specification and the appended claims, the singular forms xe2x80x9caxe2x80x9d, xe2x80x9canxe2x80x9d, and xe2x80x9cthexe2x80x9d include plural referents unless the content clearly dictates otherwise.
The term xe2x80x9cwater solublizing functional groupxe2x80x9d is meant to define a group imparting hydrophilic properties such as sulfonic acids, carboxylic acids, sugars, quaternary amines, polyethers, phosphoric acids, boronic acids, and combinations thereof, or other similar hydrophilic groups.
The term xe2x80x9celectrophilic coupling moietyxe2x80x9d refers to a linkage through which the water solubilizing functional group can be coupled to an aromatic ring of an azomethine dye or to a linking spacer group that is, in turn, coupled to an aromatic ring of an azomethine dye. Representative of suitable coupling moieties are members selected from the group consisting of amide, amine, sulfonamide, sulfonyl, and ester linkages.
The term xe2x80x9cspacerxe2x80x9d is meant to include an aliphatic straight or branched chain hydrocarbon having from about one to ten carbon atoms that link the water solubilizing functional group to the azomethine dye. The spacer can be linked to either the water solubilizing functional group or to an aromatic ring of the azomethine dye through an electrophilic coupling moiety.
With regard to any structure where a water solublizing functional group has been added, the term xe2x80x9csolublexe2x80x9d includes any structure that has been solubilized to the extent that it is functional in an aqueous based ink.
With this in mind, an aqueous ink jet ink comprising an effective amount of an azomethine dye having at least one water solubilizing functional group covalently attached thereto is disclosed. The water solubilizing functional group can be either directly attached to the azomethine dye and/or can be attached through an electrophilic coupling moiety. If an organic spacer is used to separate the water solubilizing functional group from azomethine dye or the electrophilic coupling moiety, then straight and branched chained alkyl spacers having from about 1 to 10 carbon atoms are preferred. The azomethine dye is preferably present in the ink jet ink at from about 0.1% to 10% by weight, though any effective amount may be used. Additionally, the azomethine dye is preferably selected from the group consisting of pyrazolone azomethines, pyrazolotriazole azomethines, and combinations thereof.
Since ink jet inks are typically water-based, at least one water solubilizing functional group must be attached to the azomethine dye in order to improve the solubility of the dyes. Preferably, a plurality of water solubilizing functional groups are covalently attached to the dyes. The water solubilizing functional group can be selected from the group consisting of sulfonic acids, carboxylic acids, sugars, quaternary amines, polyethers, phosphoric acids, boronic acids, and combinations thereof, though other groups functional for solubilizing the dyes can be used in conjunction with the present invention. In a preferred embodiment, sulfonic acid groups are covalently attached to the azomethine dyes either directly to an aromatic ring, or through an electrophilic coupling moiety.
The water solubilizing functional group can be covalently attached to the azomethine dye in one or both of two preferred ways. First, the water solubilizing functional group can be covalently bonded directly to an aromatic ring on the dye. Alternatively, the water solubilizing functional group can be attached to the azomethine dye through an electrophilic coupling moiety such as an amide, an amine, a sulfonamide, a sulfonyl, or an ester. If two or more water solubilizing functional groups are attached to the azomethine dyes, in one embodiment, at least one water solubilizing functional group can be attached directly to an aromatic ring of the dye and at least one additional water solubilizing functional group can be covalently attached through an electrophilic coupling moiety.
Dyes 1 to 4 shown below provide examples of pyrazolone azomethine dyes that can be prepared in accordance with the present invention.
Additionally, dyes 5 and 6 shown below provide examples of pyrazolotriazole azomethine dyes that may be prepared in accordance with the present invention.
The pyrazolone azomethine and pyrazolotriazole azomethine structures shown above are not the only structures that are functional. These structures are merely meant to provide representative examples of functional structures. For example, though the pyrazolotriazole structures shown, i.e., dyes 5 and 6, are both pyrazolo-[1,2,4]-triazole structures, pyrazolo-[1,3,4]-triazole dye structures are also known and could be derivatized to likewise include water solubilizing functional groups in accordance with the present invention. Additionally, different water solubilizing functional groups can be used or different placement of water solubilizing functional groups can be effectuated, as long as the water solubilizing functional groups are not substantially substituted for groups that provide the color, light fastness, or other important dye function of the structure. For example, with regard to the dyes shown above, the groups that are believed to be essential to color stability and light fastness have been retained. Other groups have been replaced with sulfonic acid to improve the solubility of the structures. Additionally, in some dyes, certain appendages remain intact that can also be important in the dyes"" light fastness properties. Note that the sulfonic acid groups (or other water solubilizing functional groups) do not necessarily need to be positioned on the aromatic rings. These groups can also be attached as part of various side chains through electrophilic coupling moieties, such as through an amide, amino, sulfonamide, sulfonyl, or ether linkages.
In addition to the azomethine dyes disclosed herein, lightfastness and stability can be enhanced in many different types of dye-based inks (including, but not limited to, the azomethine dyes disclosed herein) by the addition of certain additives. These various additives are stabilizing agents that are based upon a unique type of spiroindane compound which acts as an excited singlet state quencher for many dyes. When a dye is in an excited state, i.e., electrons at a higher energy level, degradation of the dye can occur. Thus, by using the spiroindane additives disclosed herein, the excited state of various dyes can be deactivated before they have substantial opportunity to degrade. Such action is believed to extend the stability and light fastness of the dyes with which the additive is mixed. Prior to the present disclosure, such spiroindane compounds were essentially water insoluble, and thus, have not been useful for use in aqueous ink jet inks. For example, tetra-hydroxy spiroindanes, which are not sufficiently soluble in water to be effectively used in ink jet inks, are currently available commercially.
It would be useful to prepare spiroindane additives for aqueous ink jet inks having similar properties as the tetrahydroxy spiroindanes currently known. Such additives can be prepared by modifying a tetra-hydroxy spiroindane by directly functionalizing the aromatic ring with appropriate water solubilizing functional groups, or preferably, by functionalizing the aromatic rings with water solubilizing functional groups through straight or branched spacers having from about 1 to 10 carbon atoms. More preferably, from 3 to 10 carbon atoms can be used in order to substantially maintain the quencher properties of the compound. One effective spacer is a straight chained propyl group.
Specifically, a spiroindane additive of the present invention can be defined as Formula 7 below:
wherein each R group can independently be H or contain a water solubilizing functional group, with the proviso that at least one R group contain a water solubilizing functional group. The water solubilizing functional group can be covalently attached to the aromatic ring or can be attached through a spacer. However, though only one is required, it is preferred that from 2 to 4 R groups contain a water solubilizing functional group. Additionally, Rxe2x80x2 can be independently selected from the group consisting of H and straight or branched chain alkyl having from about 1 to 5 carbon atoms.
If the water solubilizing functional group is attached through a spacer, then straight or branched carbon chains having from about 1 to 10 carbons atoms are functional, though from 3 to 10 carbon atoms are preferred. Specifically, it is preferred that when the R group is a spacer/water solubilizing functional group combination, then the R group of Formula 7 be independently selected from the group consisting of xe2x80x94R2SO3H, xe2x80x94R2COOH, xe2x80x94R2N(CH3)3+, and R2(CH2CH2O)nCH2CH2OR3 , where R2 can be 1 or 2 carbon atoms, but is preferably a straight or branched carbon chain having from 3 to 10 carbons. However, as mentioned, a straight three carbon chain (propyl) is the most preferred, particularly with respect to the use of sulfonic acid as the solubilizing group. In the case of the polyetheylene oxide structure shown, n can be from 1 to 10 and R3 can be H, CH3, or CH2CH3. The water solubilizing functional groups can also be any other water solubilizing functional group that provides improved solubility. For example, groups including sugars, polyols, and pyridiniums, e.g., N-methylpyridinium, can be functional.
These spiroindane compounds, when incorporated into an aqueous dye-based ink, can be comprised of an effective amount of a dye-based colorant and an effective amount of the essentially water soluble spiroindane additive. However, about 1 to 20% by weight of the spiroindane additive is considered to be preferred. Additionally, though the stability and light fastness can be improved in many types of dye-based inks, stability and light fastness of the azomethine dyes of the present invention can further be improved by the spiroindane additives disclosed herein.

Dye-based ink jet compositions having improved stability and light fastness


An optical scanning device including a light source, a deflection device to deflect a light beam from the light source, an image focus optical system to focus the light beam deflected by the deflection device on a scanned surface to form an image thereon and scan a surface by the light beam deflected by deflection device to form an image thereon, a light path switching device provided between the light source and the deflection device, which switches a light path of the light beam emitted from the light source to deflect the light beam on different timings such that the light beam scans different surfaces.

1. Field of the Invention
The present invention relates to an optical scanning device.
2. Discussion of the Background
With the advance of colorization and high speed performance in an electrophotographic image forming apparatus for use in a laser printer, a digital copier and a facsimile machine, a tandem type image forming apparatus, which has multiple (typically four) image bearing members, has been widely diffused.
As a color image forming apparatus, there is a system which has only one image bearing member and rotates the image bearing member a number of times corresponding to the number of colors. For example, in the case of one image bearing member and four colors, the image bearing member is required to rotate four times, meaning the productivity thereof is inferior.
On the other hand, in an image forming apparatus adopting a tandem arrangement, the number of the light sources inevitably increases. This leads to an increase in the number of component parts, color displacement caused by differences between wavelengths among multiple light sources and an overall cost increase. In addition, deterioration of a semiconductor laser leads to a breakdown of a writing unit (optical scanning device).
As the number of light sources increases, the probability of breakdown naturally increases and thus the opportunity to recycle decreases. This demerit is especially significant when a surface-emitting laser or an D array is used as a light source.
As an optical scanning device which outputs images at a high speed with a small number of light sources, there is known a system described in published unexamined Japanese patent application No. (hereinafter referred to as JOP) 2005-92129.
In this system, the light beam (hereinafter referred to as beam) from a common light source is separated and the respective separated beams are simultaneously directed onto reflection mirrors located in different stacks in a sub-scanning direction (a direction orthogonal to a main scanning direction) to scan different surfaces.
However, in the system described above, beam power from a common light source is reduced to about a half when separated, with a concomitant decrease in the efficiency of the light source power. Consequently, this system requires at least double the power used in a system using a multiple light source arrangement. The increase in power leads to deterioration of the laser beam source and further causes a breakdown of the writing unit.
The deterioration of the laser beam source invites deterioration of writing performance (i.e., deterioration in reliability) and degrades image quality.


There is provided a monitoring camera apparatus which, while ensuring waterproofness, can perform focus adjustment when a dome cover is mounted. A lens (3) is covered by the dome cover (5) which is removable. A focus adjustment mechanism (9) moves an imaging device (7) in an optical axis direction and thereby performs focus adjustment. A setting button (13) being a focus setting operation unit is arranged in the inner side of the dome cover (5), and operated when the dome cover (5) is mounted. A controller (11) controls the focus adjustment mechanism (9). The controller (11) allows the focus adjustment mechanism (9) to start focus adjustment when a predetermined focus start wait time has elapsed after operation of the setting button (13). The focus start wait time is set according to a standard mounting operation time required to mount the dome cover (5).

Monitoring camera apparatuses are widely used, and monitoring camera apparatuses not only for indoor use but also for outdoor use have been provided. Further, in addition to the conventional box-type monitoring camera apparatuses, domed monitoring camera apparatuses have recently been spreading.
The monitoring camera apparatus has a focus adjustment function of performing focus adjustment by moving the imaging device in an optical axis direction. Such focus adjustment performed by moving an imaging device is called "back-focus adjustment". A technique of automatically performing back-focus adjustment has also been proposed. This technique has been disclosed, for example, in Japanese Patent Laid-Open No. 2006-148299. Hereinafter, the automatic back-focus adjustment function is referred to as "focus adjustment function". The focus adjustment function reduces image blurring in the following scenes.
The monitoring camera apparatus, used day and night, has a function of automatically performing switching between a color mode for daytime and a monochrome mode for nighttime. This function is called "day and night function", for example. In the color mode for daytime, an infrared cutoff filter is placed in front of the imaging device. However, in the monochrome mode for nighttime, the infrared cutoff filter is removed, as a result, the average wavelength of incident light shifts. Further, in the case that infrared illumination is provided, the illumination wavelength also shifts. When the wavelength shifts, the focus position changes because of chromatic aberration of lens. Thus, in order to reduce the blurring caused by the focus position shift, focus adjustment is performed by the focus adjustment function at the time of mode switching.
The focus adjustment function is also useful in the installation operation and adjustment operation for the domed monitoring camera apparatus. In the domed monitoring camera apparatus, the lens is covered by a semispherical dome cover. For example, assume that the monitoring camera apparatus includes a varifocal lens (variable focus lens). In this case, in installing the camera, the zoom ring and focus ring of the exposed lens are manually turned with the dome cover removed, so that zoom (field angle) and focus adjustment are performed. When the adjustment operation is completed, the dome cover is mounted. In such case, since the semispherical dome cover has optical performance, the focus position may shift so that blurring occurs. Thus, in order to reduce such blurring, focus adjustment is performed by the focus adjustment function.
The focus adjustment function can be automatically started by using the filter removal as a trigger at the time of switching between the color mode and monochrome mode. However, at the time of mounting the dome cover, the focus adjustment function cannot be automatically started. Thus it is needed to provide a constitution for generating a trigger for starting the focus adjustment function at the time of mounting the dome cover.
To satisfy the above demand, the conventional monitoring camera apparatus includes an external switch on an external surface of housing for starting the focus adjustment function. The dome cover is mounted and then the external switch is operated, so that focus adjustment is performed. The reason for installing the switch on the external surface is that the switch must be operated after mounting the cover.
Further, a controller apparatus may be connected to the monitoring camera apparatus. In this case, a trigger for starting the focus adjustment function can be generated by using the controller. For example, a small-sized controller is connected via a cable to the monitoring camera apparatus. Then, a menu screen is opened on the controller, and an instruction for focus adjustment is inputted as a trigger.
In the conventional monitoring camera apparatus for indoor use not requiring waterproofness, the external switch for starting focus adjustment can be installed. However, in the monitoring camera apparatus for outdoor use, the external switch is disadvantageous for ensuring waterproofness. Further, the external switch is disadvantageous in terms of appearance. When the external switch cannot be installed, focus adjustment cannot be performed at the time of mounting the cover.
If the external controller apparatus described above can be connected, focus adjustment can be started without installing the external switch. However, generally, the external controller is provided for the user separately from the monitoring camera apparatus. Not all users have the external controller. It is rather appropriate to say that many users don't have the external controller. In view of the above, it is desirable that the monitoring camera apparatus achieve required functions while the external controller is not connected. Focus adjustment is included in such required functions. Thus, even in a case where the external controller can be connected to the monitoring camera apparatus, there is a need to provide a constitution for starting focus adjustment function without using the external controller.
The above described problem is noticeable for vandal-proof monitoring camera apparatuses. The vandal-proof monitoring camera apparatuses have robustness for protection against breakage. In this case, robustness is implemented by increasing the wall thickness of cover; and since a thick cover is provided, the variation in optical path length increases, so the above described problem becomes noticeable.


The present invention relates to glide rings for use with a carrier for transporting articles through pneumatic tube systems, and more particularly, glide rings comprising Velcro.RTM. secured plastic or rubber strips to allow efficient replacement of said glide rings. The glide rings have an outer cross-sectional dimension which allow them to engage the inner surface of the passageway of the pneumatic tube system. This provides stability to the carrier and allows the carrier to be moved in response to the controlled air pressure within the passageway. Each of the glide rings has a small width in relationship to the overall length of the closed elongated compartment, and each is located in proximity to the ends of the carrier.

The transporting of articles via pneumatic tubes is old and well known. Basically, an object is placed within a container which is then transported by air under either positive or negative pressure from one destination to another. The transport is moved within a closed tube of the same configuration as the carrier extending between the destinations.
One area of commerce which currently uses the pneumatic tube and the transporting of material via the pneumatic tube on a fairly regular basis is the hospital or biomedical research/manufacturing industry. One particular application of this technology is in the area of transporting blood samples, medicines, viral samples or other biological or chemical matter between diverse locations within a hospital or laboratory. In that environment, for example, test tubes are placed within a tube carrier, and are typically secured by foam or clamps within the carrier. The purpose of securing the samples (which are often contained within glass test tubes with rubber stoppers) is to help prevent breakage. When glass breaks or stoppers become dislodged (as can happen when hospital workers fail to properly secure the stopper in the first place), chemical or biological substances can leak into the interior of the carrier.
If the leaking substance is of a large enough quantity, the substance (often a fluid) can leak out of the carrier. In that case, the entire tube transport system could become contaminated with the substance. For example, if a substance (for example, blood, saline or other fluids) were to leak out of a carrier, the substance would interfere with the carriers' efficiency. More specifically, however, fluids escaping from the carrier could make passage of the carrier difficult, resulting in enhanced downtime and increased maintenance expense.
Every day use of the carriers in pneumatic tube systems causes the glide ring seals to become worn, and hence, not maintain the tight, consistent and secure fit within the interior of the carrier tube. As the carriers sometimes reach speeds in excess of 25 feet per second, the rings serve to form an air barrier around the carrier so the carrier does not jam. Also, by minimizing air leakage around the carrier, the rings can minimize the air required to propel the carrier. As the rings become worn with use, the air barrier around the carrier is eliminated and chances of the carrier becoming lodged in the tube increases. Also, it becomes necessary to use much more air pressure to move the carriers at the same rates as with tight, consistent and secure fitting rings.
There exists a need in the field to provide a carrier with accelerator or glide ring seals which are easily replaceable, remain securely attached to the exterior of the carrier, and maintain a tight, consistent and secure fit between the carrier and the interior of the tubes.
There also exists a need in the field to provide a carrier with suitable watertight and airtight properties, such that matter from within the carrier cannot escape to the outside, and matter that has become uncontrollable within the carrier can activate a warning indicator on the exterior of the carrier, so that hospital or other workers who use the carriers will not open carriers that have an activated warning signal, which is indicative of a spill or other abnormal condition within the carrier.
Prior art known to the inventor includes U.S. Pat. No. 4,948,303 to Good, U.S. Pat. No. 4,324,511 to Irish, U.S. Pat. No. 4,219,290 to Golston, U.S. Pat. No. 4,149,685 to Leavelle, and U.S. Pat. No. 3,825,210 to Weaver, which are incorporated herein by reference.
U.S. Pat. No. 4,948,303 to Good discloses a pneumatic tube carrier with a reinforced hinge.
U.S. Pat. No. 4,324,511 to Irish discloses a pneumatic tube carrier with an accelerator ring.
U.S. Pat. No. 4,219,290 to Golston discloses a hinged pneumatic tube carrier with an improved side opening mechanism.
U.S. Pat. No. 4,149,685, granted to Leavelle, Apr. 17, 1979 discloses a pneumatic carrier having identical halves and includes means to adjust the latch mechanism.
U.S. Pat. No. Re. 30,882 granted, Mar. 16, 1982, to Leavelle is directed to an adjustable closure mechanism.
U.S. Pat. No. 3,825,210, granted to Weaver, Jul. 23, 1974 discloses a "clamshell" type pneumatic tube carrier of a bullet configuration wherein the seals which substantially fill the tube are not immediately adjacent the ends but are spaced therefrom.
U.S. Pat. No. 242,459 to Leaycraft Jun. 7, 1881 which discloses a pneumatic tube carrier having asymmetric hinged halves being continuously urged to a closed position by a spring means.
U.S. Pat. No. 359,456 granted to McLaughlin, Mar. 15, 1887 discloses a pneumatic tube carrier including a spindle or the like for wrapping a paper document for security during transportation from one location to another.
U.S. Pat. No. 452,471 granted to Barri, May 19, 1891 discloses a pneumatic tube apparatus wherein an opening in the surface of the container is created by twisting one coaxial section with respect to the other.
U.S. Pat. No. 769,233 granted to Pfluger, Sep. 6, 1904, discloses a cash box for use with a pneumatic tube wherein an opening in the carrier is exposed by relative twisting of the two coaxial elements.
U.S. Pat. No. 811,915 granted to Hager Feb. 6, 1906, discloses a pneumatic tube carrier including a specific stop member to prevent damage to the cylinders when the two coaxial halves are twisted relative to each other.
U.S. Pat. No. 1,169,553 granted to MacMillan, Jan. 25, 1916, discloses a means for securely latching a pneumatic tube carrier such that it does not accidentally open in transport.
U.S. Pat. No. 1,827,000 granted to Duffin Oct. 13, 1931, discloses a container for a roll of paper wherein the exterior container includes a hinge which connects two halves which are identical with the exception of an internal flap on one side for securing the container in a closed condition.
U.S. Pat. No. 2,251,238 granted to Busch, Jul. 29, 1941, discloses a pneumatic carrier wherein the coaxial halves are twisted with respect to each other to expose a window opening and includes a spring actuated locking device.
U.S. Pat. No. 3,401,902 granted to Gouyou-Beauchamps et al, Sep. 17, 1968 discloses a large dimension open top carriage for use in pneumatic conveying of large objects.
U.S. Pat. No. 3,593,948 granted to McClellan, Jul. 20, 1971, discloses a pneumatic carrier wherein identical halves are hinged together along one edge and includes spring means for urging the two halves to a closed cylindrical configuration for transport.
U.S. Pat. No. 3,761,039, granted to Hazell, Sep. 25, 1973 discloses a pneumatic carrier system including means for transferring documents from one individual carrier to another, enabling the use of sharp corners (transfer stations) in the transport tube itself.
U.S. Pat. No. 4,470,730, granted Sep. 11, 1984, to Wutherich discloses a pneumatic tube carrier having a separate pocket means to separate coinage from paper money during transport.
In general, pneumatic tube systems known in the art include a closed continuous passageway having a predetermined inner cross-sectional dimension where the passageway includes a plurality of curves or bends having a predetermined radius. A fluid, such as air, is controllably forced through the passageway in a loop to move a carrier through the passageway. In order for the carrier to move freely through the passageway, the dimensions, and in particular the length, of the carriers being used have been limited by the inner cross-sectional dimension and curvature radius of the passageway. Pneumatic delivery systems are used extensively for the rapid and efficient transportation of a wide variety of articles. These delivery systems are used in a number of business operations, including banks, hospitals, office buildings, industrial plants, and truck terminals as a few examples.
Pneumatic carriers for use in such delivery systems come in a wide range of sizes and shapes to accommodate the physical articles to be transported in the system. As an example, pneumatic carriers are provided for transporting cash, messages, stock transaction slips, letters, blueprints, electronic data processing cards, x-rays, pharmaceutical supplies, and a variety of other small physical objects.
In the past, various mechanisms have been utilized as closure devices for pneumatic tube carriers. For example, many such carriers include an end cap that is hinged with respect to a cylindrical hull on one side of the hull and which has a latch that releasably fastens the end cap to the opposite side of the hull in a closed position. Such carriers employ a variety of fasteners, such as snap fasteners, elastic straps with eyeholes that fit over hooks, or straps that may be secured to bendable posts.
Other types of pneumatic tube carriers are of the side opening variety. One conventional form of such a carrier employs two generally semi-cylindrical sections that are hinged along one longitudinal edge. The hinged sections may be swung toward or away from each other to effectuate opening and closing of the carrier hull. Locking is achieved by virtue of the end caps, which may be twisted to effectuate threaded engagement of the caps onto the carrier hull ends when the hinged hull sections have been closed. That is, the end caps are rotated in such a fashion as to be drawn towards each other onto the ends of the hull, thereby immobilizing the hull sections relative to each other. Rotation of the end caps in the opposite direction releases the hull sections and allows them to be opened.
A preferable configuration utilized by many carrier manufacturers is that of a side opening, wherein the two sides are hinged together, and the two sides are held together when the carrier is closed by use of a hook, or detent or indented type locking lip. Such carriers include latching mechanisms to prevent the door from coming ajar or opening during transit, which could cause the carrier to become lodged in the pneumatic tubes and would also allow the contents of the container to spill out into the tube system. In addition, the instructions for latching such side opening containers or carriers are simple to follow, so that the container can be easily placed within the tube system. Such hinging and locking mechanisms make waterproofing or sealing the carrier a particularly difficult task, as the hinges and locks are embedded within the mold of the carrier, which is generally formed of plastic.
In another type of side opening pneumatic carrier, the access to the carrier is gained by simultaneously pulling and twisting the ends of the carrier to allow the side opening door to be opened. The instructions for such a two-step process are often difficult for many banking customers to follow, and the physical effort and manual dexterity needed to simultaneously pull and twist both ends of the carrier against a spring resistance is often troublesome for many banking customers.
A need has thus arisen for an improved type of pneumatic carrier which overcomes these and other disadvantages associated with the prior art devices. In particular, a need has arisen for a pneumatic tube carrier having easily replaceable glide or travel or accelerator rings which do not interfere with the opening and closing of the carrier. Also, the carrier must be able to maintain its air barrier and tightness within the interior of the tube, despite the fact that it is subjected to a vacuum transport system, and despite the fact that it will be subjected to extreme environmental conditions, such as repeated use, frequent drops, dust and dirt particles, high speed travel, and the like.
Finally, in the past, heat guns were often used to "un-glue" glide rings from their respective tube carriers, as the glide rings had to be well-secured to the carrier. As the carriers proceed through the pneumatic tube carrier systems, they invariably encounter hostile conditions, such as dust, dirt, ruts in the interior tube walls, twists, turns and bends, and so on. Over time, the glide rings wear out, and so, replacement maximizes the performance of the overall system. Thus, replacement should be simplified, while not compromising the strength of the bond between the glide rings and the pneumatic tube carriers. Also, whatever is used to secure the glide ring to the carrier must be of minimal thickness, so the carrier will fit into traditional tubes, without modification as to size.

Removable glide rings for pneumatic tube carriers


A miter rail system for spanning a railroad track joint including a fixed rail, a lift rail and a rider rail connected to the fixed rail. The rider rail has an upper surface including a central portion defined by an arc of constant radius and opposite end portions. The apex of the central portion is greater in height than the height of the fixed rail and lift rail, and the height of the opposite end portions at opposed end faces of the rider rail is sufficiently low to avoid contact by a rolling stock wheel.

Railroad bridges are frequently erected over waterways trafficked by pleasure boats, merchant ships or military vessels. The superstructures or equipment carried by the superstructures of these craft are sometimes quite high with respect to the water surface and may extend above the elevation of a railroad bridge deck. Several types of railroad bridges have movable decks to permit passage of tall vessels as the need arises. Although their methods of operation may vary, such bridges possess at least one characteristic in common. That is, at least a portion of the bridge deck may be selectively disposed into a first position for permitting passage of rolling stock thereover and a second position for permitting passage of watercraft by or under the deck. Included among these classes of bridges are the vertical lift bridge, the bascule bridge and the swing bridge. A vertical lift bridge normally includes a pair of towers disposed on opposite ends of a bridge deck which include machinery for raising and lowering the deck while maintaining the deck in substantially horizontal orientation. A bascule bridge typically includes a bridge deck pivotally connected about a horizontal pivot axis to a bridge approach, pier, or the like, such that the deck may swing upwardly and downwardly. In a swing bridge, the deck is generally supported atop a turntable and rotates approximately 90.degree. in a substantially horizontal plane between rail passage and watercraft passage positions.
Steel rail or track is subject to thermal expansion and contraction. Accordingly, a certain gap must be maintained between the ends of rails or tracks carried by a movable bridge deck and the ends of adjacent rails or track. Depending on the atmospheric temperature range to which the bridge is likely to be exposed and the length of rails involved, the required gap may range from about one to three inches or more. However, traverse of gaps of this magnitude by the wheels of rolling stock is not recommended because of the potential for wheel and/or track damage and possible derailment of the rolling stock.
Miter or rider rails are transition rails used to bridge the gap between adjacent ends of a section of vertically movable track and a section of stationary track known as the "running rails". CMI-Promex, Inc. of Pedricktown, N.J. manufactures a miter rail system including a rider rail approximately three feet in length which is bolted to an end of the stationary rail and spans the distance between the ends of the stationary and movable rails. The rider rail has a convex upper surface of constant radius whereby the upper surface of the rider rail is slightly lower than the running rails at its ends and slightly higher than the running rails at its center.
As the wheels of rolling stock travel over a running rail and encounter the rider rail they become supported by the rider rail and slightly lifted with respect to the upper surfaces of the running rails. Upon passing the rider rail, the wheels come into contact with the upper surface of the running rail at the downstream side of the track joint.
As is known, rolling stock wheels have two rail contacting surfaces, the "flat" and the "flange". The flat contacts the upper surface of the head portion of rail or track. the flange extends substantially perpendicular to the flat and contacts the substantially vertical inner face of the head portion of the rail. The flat bears the majority of the weight of the rolling stock and the flange functions to keep the wheels in engagement with the track. To enhance reliable contact between the rolling stock wheels with the underlying track, the opposed rails of the track are usually installed slightly off vertical. More particularly, each of the rails is canted or tilted slightly inwardly toward the other at approximately 1.5.degree. from vertical.
The upper end edges or corners of the rider rails of miter rail systems such as the aforementioned CMI-Promex, Inc. system frequently become chipped off during use. The chipped areas, in turn, promote the generation and promulgation of cracks that reduce the structural integrity of the rider rails. Although the chipping damages is believed to be caused by contact with rolling stock wheels, the manner by which the rider rail ends become damaged is not fully understood, especially since the upper surfaces of the rider rails at the end regions thereof are lower in elevation than the adjacent running rails.
An advantage exists, therefore, for a miter rail system including a rider rail which is resistant to damage resulting from contact with rolling stock wheels.


A circumferential flow type dynamic pressure bearing 1 is comprised of a shaft 2 having a multiple-arc-shaped pressure generating surface and a circular sleeve 3 fitted on the shaft 2. The shaft or the sleeve is formed with a plurality of proximity portions 4 each of which is close in distance to the surface opposed thereto whereby the support force of gas is generated. A plurality of grooves 5 formed at locations spaced from each other by an angle obtained by dividing the circumference by the number of proximity portions 4 or a divisor thereof. Use of such bearing ensures compatibility with high-humidity environmental conditions by provision of grooves, and at the same time it is capable of eliminating or reducing noise generated by vibration caused by radial deviations of the shaft due to provision of the grooves.

1. Field of the Invention
This invention relates to a circumferential flow type dynamic pressure bearing having opposed surfaces formed with proximity portions that generate a support force by gas pressure to thereby carry out a high-speed rotation supporting operation. More particularly, the invention relates to a circumferential flow type dynamic pressure bearing of this kind which has grooves formed therein to secure compatibility with high-humidity environmental conditions, and is at the same time capable of reducing noise generated by vibration caused by the run-out of the grooves.
2. Description of the Related Art
The present applicant proposed a dynamic pressure bearing compatible with high-humidity environmental conditions in Japanese Unexamined Patent Publication (Kokai) No. Hei 9-210052. The bearing disclosed therein includes a circumferential flow type dynamic pressure bearing for use in a rotary mirror scanner using a rotary mirror operating at a high rotational speed. This bearing is made compatible with high-humidity environmental conditions while preserving the run-out precision.
As shown in FIG. 10, this dynamic pressure bearing 101 is comprised of a dynamic pressure shaft 102 and a dynamic pressure sleeve 103 fitted thereon. The dynamic pressure shaft 102 has opposed surfaces formed with proximity portions 104, and the dynamic pressure sleeve 103 has a groove 105 serving as a water drain passage.
The proximity portions 104 are portions formed to provide reduced clearance between the opposed surfaces of the shaft 102 and the sleeve 103, whereby the support force of gas pressure is generated by the relative rotation of the shaft 102 and the sleeve 103 with respect to each other without producing a flow of the gas in the axial direction. This prevents foreign matter from being drawn in and thereby enables the bearing to maintain the precision over a long period of time. Further, the groove 105 prevents moisture vapor from being liquefied by the change in gas pressure so that it is possible to prevent a water layer from forming without requiring the flow of gas in the axial direction. Thereby, abnormal loads are prevented from being applied to the bearing due to the water layer under high-humidity environmental conditions.
The dynamic pressure shaft 102 of the dynamic pressure bearing 101, however, undergoes run-out or radial deviation of the axis thereof due to an imbalance which occurs whenever each proximity portion 104 passes by the groove 105 during rotation of the shaft 102. If the shaft 102 has a triple-arc-shaped pressure-generating surface, it undergoes three radial deviations per rotation of the shaft. Hence, it generates vibrations having a frequency three times as high as the rotational speed of the shaft 102. Due to this vibration, problems are caused in that temporary audible sounds are produced in the course of change in the rotational speed before the operating rotational speed of the bearing is reached. This problem of noise generated by vibration caused by radial deviations of the shaft has not been solved even by forming the groove into a helical shape.

Circumferential flow type dynamic pressure bearing


A controller controls operation of a HVAC&R device, bringing the temperature inside a structure from a first temperature to a second temperature at a predetermined time each day. Sensors sense the temperature both inside and outside the structure. A recovery time is calculated based upon a previously calculated air treatment rate of temperature recovery for the HVAC&R device to drive the temperature of the structure through a temperature change, the recovery time calculation being obtained by multiplying the difference between the sensed temperature inside the structure and the second temperature by the previously calculated air treatment rate. A correction factor is calculated based upon a relationship between the sensed outside temperature and a previously sensed outside temperature, the correction factor being added to obtain a corrected recovery time. The HVAC&R device is initiated at a time defined by the predetermined time subtracted from the corrected recovery time.

The present invention relates generally to a control application for a HACK&R system. More specifically, the present invention relates to a system and method for start-up control of a HVAC&R system.
To minimize energy costs, a structure having a heating, ventilation, air conditioning and refrigeration (HVAC&R) or air treatment system for achieving climate control uses temperature settings that are initiated at HVAC times. For example, in warmer weather, the temperature setting for the structure is set at a higher level during unoccupied hours, and set at a lower level during occupied hours. This lower level temperature setting is an occupied set point or occupied setpoint temperature. It is desirable for the HVAC&R or air treatment system to achieve the occupied setpoint temperature at the start of the time period or setpoint time corresponding to the occupied hours, typically the start of a work shift. To accomplish this, the HVAC&R system must be initiated with sufficient time prior to the setpoint time to allow the HVAC&R system to cool the structure to the desired setpoint temperature, typically referred to as the recovery time. However, initiating the HVAC&R system too far in advance of the start of the setpoint time causes the HVAC&R system to reach the setpoint temperature before the setpoint time, thus wasting energy. Conversely, initiating the HVAC&R system too close to the setpoint time causes the HVAC&R system to achieve the setpoint temperature after the setpoint time has passed, subjecting the occupants in the structure to temperature settings that are outside their comfort level until the setpoint temperature is achieved.
One solution to this problem, U.S. Pat. No. 4,522,336 describes a start/stop controller for controlling an air treatment apparatus at a reduced energy consuming level during periods of non-occupancy of a building and for energizing the air treatment apparatus for occupancy so that the building is comfortable for occupancy. An adjustment time is calculated by taking the difference between the comfort temperature and the setback temperature, and then dividing this temperature difference by the rate of temperature change achieved by the air treatment apparatus. The rate of temperature change is obtained by calculating the temperature difference by the change in time. However, the controller of U.S. Pat. No. 4,522,336 is not adaptive, i.e., it does not take into account variations in the building, control system, or day-to-day differences in outside ambient temperature, and requires application of an arbitrary adjustment factor if the adjustment time falls outside a threshold range. One drawback of this technique is that the arbitrary adjustment factor, as disclosed, can act to increase the time differential between the time the setpoint temperature should be reached and the time the setpoint temperature is actually reached, providing inconsistent climate control inside the building.
What is needed is an adaptable startup control for use with HVAC&R systems that is simple to operate which can provide an optimized startup time for consistently achieving an occupied setpoint temperature at a daily predetermined setpoint time.


This invention offers a manufacturing method to reduce a manufacturing cost of a semiconductor device having a through-hole electrode by simplifying a manufacturing process and to enhance yield of the semiconductor device. A first insulation film is formed on a top surface of a semiconductor substrate. A part of the first insulation film is etched to form an opening in which a part of the semiconductor substrate is exposed. Then a pad electrode is formed in the opening and on the first insulation film. A second insulation film is formed on a back surface of the semiconductor substrate. Then a via hole having an aperture larger than the opening is formed. And a third insulation film is formed in the via hole and on the second insulation film. The third insulation film on a bottom of the via hole is etched to expose the pad electrode. After that, a through-hole electrode and a wiring layer are formed in the via hole. Finally, the semiconductor substrate is cut and separated into a plurality of semiconductor dice.

1. Field of the Invention
This invention relates to a manufacturing method of a semiconductor device, specifically to a manufacturing method of a semiconductor device having a through-hole electrode.
2. Description of the Related Art
A CSP (Chip Size Package) has received attention in recent years as a three-dimensional mounting technology as well as a new packaging technology. The CSP means a small package having about the same outside dimensions as those of a semiconductor die packaged in it.
A BGA type semiconductor device with a through-hole electrode has been known as a kind of CSP. This BGA type semiconductor device has a through-hole electrode that penetrates through a semiconductor substrate and is connected with a pad electrode. And a plurality of ball-shaped conductive terminals made of metal such as solder is arrayed in a grid pattern on a back surface of the semiconductor device.
When the semiconductor device is incorporated into electronic equipment, each of the conductive terminals is connected to a wiring pattern on a circuit board such as a printed circuit board.
Such a BGA type semiconductor device has advantages in providing a large number of conductive terminals and in reducing size over other CSP type semiconductor devices such as an SOP (Small Outline Package) and a QFP (Quad Flat Package) that have lead pins protruding from their sides.
Next, a conventional manufacturing method of the BGA type semiconductor device with the though-hole electrode will be described referring to the drawings. FIGS. 24-27 are cross-sectional views showing the conventional manufacturing method of the semiconductor device.
First, a pad electrode 52 is formed on a top surface of a semiconductor substrate 50 through a first insulation film 51, as shown in FIG. 24. Next, a supporting body 54 is bonded to the top surface of the semiconductor substrate 50 through a resin layer 53, when necessary.
Next, a second insulation film 55 is formed on a back surface of the semiconductor substrate 50 and a photoresist layer 80 is selectively formed on the second insulation film 55. The photoresist layer 80 has an opening at a location corresponding to the pad electrode 52. A via hole 56, which penetrates through the semiconductor substrate 50 and the second insulation film 55 and exposes the first insulation film 51, is formed by etching the second insulation film 55 and the semiconductor substrate 50 using the photoresist film 80 as a mask.
Furthermore, the first insulation film 51 exposed at a bottom of the via hole 56 is removed by etching using the photoresist layer 80 as a mask, as shown in FIG. 25.
Next, a third insulation film 57 is formed on a surface of the via hole 56 and on the second insulation film 55, as shown in FIG. 26.
Then the third insulation film 57 on the bottom of the via hole 56 is removed by etching from the back surface of the semiconductor substrate 50 to expose the pad electrode 52, as shown in FIG. 27.
Furthermore, a through-hole electrode (not shown) that is connected with the pad electrode 52 is formed in the via hole 56. And a wiring layer (not shown) connected with the through-hole electrode is formed on the back surface of the semiconductor substrate 50. A protection layer (not shown) is formed over the back surface of the semiconductor substrate 50 including the wiring layer. Then a portion of the protection layer is removed to expose a portion of the wiring layer, and a conductive terminal (not shown) is formed on the portion of the wiring layer. After that, the semiconductor substrate 50 is separated into a plurality of semiconductor dice by dicing.
Further description on the technologies mentioned above is disclosed in Japanese Patent Application Publication No. 2003-309221, for example.
In the conventional manufacturing method of the semiconductor device described above, however, the third insulation film 57 is formed after the pad electrode 52 is exposed by etching the first insulation film 51 on the bottom of the via hole 56 as shown in FIG. 25, and then the pad electrode 52 is exposed once again by etching the third insulation film 57 on the bottom of the via hole 56 as shown in FIG. 27. That is, two times of etching are required to expose the pad electrode 52 at the bottom of the via hole 56 while keeping the third insulation film 57 on a side wall of the via hole 56.
In addition, there is a problem that corners of the semiconductor substrate 50 are exposed at the bottom of the via hole because of convergence of electric field and over etching at the corners during the etchings to remove the first insulation film 51 and the third insulation film 57 on the bottom of the via hole 56. As a result, insulation failure is caused later between the through-hole electrode (not shown) formed in the via hole 56 and the semiconductor substrate 50.
In order to avoid the insulation failure between the through-hole electrode and the semiconductor substrate 50, the etchings must be controlled very carefully so that amounts of etching of the first insulation film 51 and the third insulation film 57 are kept as small as possible, while the pad electrode 52 is securely exposed. This makes process in the manufacturing method of the semiconductor device complicated, raising a problem of increased manufacturing cost.
And when the etching of the first insulation film 51 is insufficient, there arises a problem of electrical connection failure between the pad electrode 52 and the through-hole electrode (not shown) to be formed in the via hole 56. This reduces yield of the semiconductor device.

Manufacturing method of semiconductor device


A thin disk force sensor having measuring elements of not more than five layers including force introducing layers welded under preloading to a thin disk housing. The measuring elements, weld and disk housing are planarized. A vapor deposited layer is selectively applied to the force measuring elements to increase the applied force compared to the housing.

Disk-shaped and annular force sensors based on piezoelectrics and strain gauges are available commercially. For about 20 years, quartz load washers have become known for measuring dynamic single- and multi-component force processes. This design is characterized by the crystals being arranged between two rigid and solid disks, with the introduced forces transmitted for the most part through the piezo disks. This results in an overall height about two or three times the height of a standard washer. Examples are shown in DP 1 929 478 and CH 476 990 which corresponds to U.S. Pat. No. 3,614,488 and 3,582,691 respectively. As a result of modern amplifier technique, it is enough to detect only part of the effective forces, which is effected most simply by paralleling the force. This however is conditional upon the relation .alpha. where ##EQU1## not changing during the observation time. Values of .alpha. may range from 2 to 10,000 depending on application. A force sensor of this kind in a rectangular platform is shown in DE 34 40 670 C2. In such measuring plates, commercial piezo force measuring disks are glued. In these plates, very critical installation heights in relation to the measuring plate surface must be modified to within a few microns by adapter plates and thrust washers. One consequent of this serial array of disks (the commercial force measuring disk already has five of them) is a great uncertainty in the detection of the paralleled force transmission. This is because the contact surfaces of eight disks arranged in series have ten air gap layers, which have different ratios of elasticity depending on preloading. Owing to the ten different air gaps, the individual force measuring disks of such a measuring plate will always give different force measuring signals under the same loading, because the effects of the air gap layers are difficult to bring under control.
The purpose of this invention is to provide measuring disks whose measuring elements have not more than half as many air gaps, i.e. less than five. To achieve this, the disks are welded singly into the measuring elements under high preload. After this, the disk surfaces are ground over and possibly lapped together with the cover disks of the measuring elements, to obtain a perfect base or common planar surface. The measuring element cover disks can then be coated with an exactly determine vapor-deposition layer using a stencil. This enables the thin disk force sensor, according to the invention, to be fitted much easier, more accurately and reliable without additional adapter plates and thrust washers to be matched. Moreover, the overall height can be kept much lower, equivalent to that of standard washers, because no commercial force sensors are fitted in it but only components of the force sensors.
According to the invention, measuring elements are fitted in the sensor which may be sensitive in all three space coordinates X, Y, Z as well as to moments M. The defined force paralleling is obtained by vapor deposition onto the ground-over state. The reduction of the number of air gap layers and their minimization by welding under high mechanical preload allows using standardized disk elements and creates a new category of thin disk force sensors.
The invention is based primarily on piezoelectric measuring principles used with impedance transformer or charge amplifier. Quartz (S10.sub.2) is employed usually as piezo material, allowing measuring cycles lasting up to 15 minutes in conjunction with modern charge amplifiers, so that perfect static calibration is possible. With impedance transformers only brief phenomena can be detected, but these can be integrated in simple fashion into the sensors. Commercial impedance transformers for pressure and force sensors are described in the literature under the trade name "Piezotron transducers".
The use of piezo-ceramics yields stronger signals, but they are usable only for short-period measurements, while static calibration is possible though difficult. Nevertheless, they allow much smaller elements, which may offer advantages. However, since quartz plates can be stressed in both compression and shear depending on the crystal out, quartz has proved to be the ideal material for multicomponent dynamometry.
The invention may embody other known sensor techniques however. Thus the use of thin and thick film processes is conceivable, also capacitive principles, though only for single-component force measuring. Nevertheless, the piezoelectric principle is far superior owing to the high rigidity attainable.
The following remarks refer exclusively to piezoelectric arrangements therefore.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Thin disk force sensor and method of making


A thermostat is provided comprising a first connector for connecting to an air conditioner, a second connector for connecting to either a conventional heater or a heat pump reversing valve, and a selection means for selecting from at least a first mode of operation and a second mode of operation. The first mode of operation is configured to establish cooling by providing an on signal to the first connector and to establish heating by providing an on signal to the second connector. The second mode of operation is configured to establish cooling by providing an on signal to the first and second connectors, and heating by providing an on signal to the first connector but not the second connector. When the second mode is selected and the second connector is connected to conventional heating, the thermostat detects when both the conventional heating and air conditioning are operating simultaneously during cooling.

Thermostats are typically used to control climate control systems to maintain the temperature of the space conditioned by the climate control system. A conventional thermostat compares the sensed temperature of the space with a set point temperature and activates the climate control system to heat or cool the space to the desired set point temperature. Some heating systems may comprise a fuel-fired heating system, while others comprise a heat pump and an auxiliary heat system. Various types of thermostats are available to control heating by turning on a fossil fuel furnace or alternatively a heat pump system depending on which system is installed. In the case of a heat pump with a back-up heat system, the thermostat controls both systems by turning on the heat pump when there is a demand for heating, and turning on the auxiliary heat system when the heat pump is not providing adequate heating. However, present thermostats cannot identify connection to a heat pump or a conventional heating system, or problems with miss-connection to such systems. In fact, a thermostat inappropriately connected to either system would cause inability of the system to achieve the set point temperature, and would only exacerbate the problem by continuing to request operation of the problematic system.

Thermostat for a heat pump or conventional heating system


The invention provides a pulsation free pump which includes a plurality of hydraulic diaphragm pumps, a plurality of plungers corresponding to the hydraulic diaphragm pumps, each of the plungers performing a reciprocal movement which provides a pumping cycle operation of corresponding one of the plurality of hydraulic diaphragm pumps and an adjustable exhaust differential pressure regulating valve. Each of the pumping cycles includes a discharge process and a subsequent suction process. A controller is provided for controlling reciprocal movements of the plungers in association with each other at a predetermined difference in phase of the pumping cycle. The controller controls the reciprocal movement of each of the plungers so as to set a preliminary pressure-rising process just before the discharge process so that a discharge flow rate of each of the diaphragm pumps is initiated to increase without any time delay when the pumping cycle enters into the discharge process so that a total discharge flow rate defined by the sum of the discharge flow rates of all of the plungers is kept constant and free of any substantial pulsation.

The present invention relates to an automatic air extraction hydraulic diaphragm pump driven by a cam mechanism, and more particularly to a pulsation free pump provided with a pulsation adjustable feature capable of adjusting variable pulsation of a pump discharge liquid to be minimum during operations of the pumps.
Twin pulsation free pumps are illustrated in FIGS. 1A and 1B and have generally been known. In FIG. 1A, two automatic air extraction hydraulic diaphragm pumps P1 and P2 are arranged in parallel to each other to be driven by a cam mechanism 10 at a phase difference of 180.degree.. In FIG. 1B, two automatic air extraction hydraulic diaphragm pumps P1 and P2 are arranged in series to be driven by a cam mechanism 10 at a phase difference of 180.degree.. The first and second pumps P1 and P2 have pump chambers 12, 12 which are coupled to a single suction inlet pipe 14 and to a discharge pipe 16. The first and second pumps P1 and P2 also have hydraulic chambers 18, 18 which are coupled through automatic air extractors 20, 20 to oil reservoirs 22, 22.
Similarly, triple pulsation free pumps may be constituted by three automatic air extraction hydraulic diaphragm pumps driven by a cam mechanism at a phase difference of 120.degree..
FIG. 2A is illustrative of a property in a theoretical discharge flow rate of the above twin pulsation free pumps. FIG. 2B is illustrative of a property in an actual composite discharge flow rate of the above twin pulsation free pumps. FIG. 3A is illustrative of a property in a theoretical discharge flow rate of the above triple pulsation free pumps. FIG. 3B is illustrative of a property in an actual composite a discharge flow rate of the above triple pulsation free pumps.
The conventional pulsation free pumps described above, however, exhibit undesirable pulsation discharge flows due to the following five factors.
The first factor is concerned with a clearance in the driving section. The second factor is concerned with a residual air in a hydraulic driving section. The third factor is concerned with a leakage of the liquid in an air extraction process. The fourth factor is concerned with a residual air in a pump operation section. The fifth factor is concerned with a leakage of the liquid from a check valve. Due to the above factors, the first pump P1 positioned to follow the second pump P2 shows a delay (.DELTA.t) in time of the discharge as well as a loss (.DELTA.q) of the discharge flow rate. The following descriptions will focus on each of the influences caused by the above five factors.
As to the first factor concerned with the clearance in the driving section, even if a clearance exists in a rotation driving section, no change in the discharge flow rate appears due to the clearance being unidirectional. If, however, a clearance exists in a reciprocal driving section then the direction of the clearance is different between the discharge and suction processes thereby a waveform of the actual discharge flow rate of the first pump P1 is shifted from the theoretical waveform thereof in a direction of delay as illustrated in FIG. 4A. Particularly, the clearance direction is changed at a time .theta..sub.3 when the first pump P1 enters into a suction process. As a result, the composite discharge flow rate is reduced at a time when the first pump P1 initiates the discharge as well as increased at a time when the first pump P1 initiates the suction and the second pump P2 initiates the discharge as illustrated in FIG. 4B.
As to the second factor concerned with the influences of the residual air in the hydraulic driving section, at a time .theta..sub.0 when the first pump P1 enters into the suction process, an air pressure is raised thereby causing an undesirable and additional time consumption for obtaining the required discharge pressure. An increase of the discharge flow rate of the first pump P1 has a time delay (.DELTA.t1) as illustrated in FIG. 5A. The composite discharge flow rate has a certain loss (.DELTA.q1) of the discharge flow rate as illustrated in FIG. 5B.
As to the third factor concerned with the leakage of the liquid in the air extraction process, at the time .theta..sub.0 when the first pump P1 enters into the discharge process, a small amount of the oil liquid is unwillingly extracted from the hydraulic driving section during air extraction. Such oil leakage leads to an undesirable and additional time consumption for obtaining the required discharge pressure of the first pump P1 thereby an increase of the discharge flow rate has a time delay (.DELTA.t2) as illustrated in FIG. 6A. As a result, the composite discharge flow rate has a certain loss (.DELTA.q1) of the discharge at the time when the first pump P1 initiates the discharge as illustrated in FIG. 6B.
As to the fourth factor concerned with the influences by the residual air in the pump operation section, at the time .theta..sub.0 when the first pump P1 enters into the discharge process, an air pressure is raised thereby causing an undesirable and additional time consumption for obtaining the required discharge pressure. An increase of the discharge flow rate of the first pump P1 has a time delay (t1) as illustrated in FIG. 5A. The composite discharge flow rate has a certain loss (.DELTA.q1) of the discharge flow rate as illustrated in FIG. 5B.
As to the fifth factor concerned with the influences due to the leakage of the liquid from the check valve, when a leakage of the liquid is generated from the check valve positioned at the discharge side of the first pump P1, then during the discharge process of the first pump P1 there appears a leakage of the discharge liquid from the inside of the first pump P1 into the suction inlet pipe thereby the discharge flow rate of the first pump P1 is totally reduced as illustrated in FIG. 7A. As a result, the composite discharge flow rate is reduced from the theoretical discharge flow rate during the discharge process of the first pump P1 as illustrated in FIG. 7B.
When a leakage of the liquid is generated at the check valve positioned at the suction side of the first pump P1, then during the discharge process of the first pump P1, the discharge liquid flows during the discharge process of the first pump P1 in a reverse direction from the discharge pipe into the inside of the first pump P1 thereby a suction flow rate of the first pump p1 is totally reduced as illustrated in FIG. 7C. As a result, the composite discharge flow rate is reduced from the theoretical discharge flow rate during the suction process of the first pump P1 namely during the discharge process of the second pump P2 as illustrated in FIG. 7D.
The above problems caused by the first and fifth factors may readily be settled by a certain design change of pump elements, whereas settlements of the problems caused by the remaining factors, namely, the second, third and fourth factors would be difficult. There has been proposed a compensation of cams in the cam mechanism 10 for settlements of the above problems due to the above second, third and fourth factors. The compensations already proposed may be classified into three types as follows.
The first proposal is to compensate the cams for changing the discharge property in an initiation stage of the discharge process. The cams in the cam mechanism 10 illustrated in FIGS. 1A and 1B are compensated in those shapes so that the discharge flow rate property is set at a waveform represented by the real line in FIG. 8B. Whereas the pulsation is generated in the discharge initiation stage, a removal of the pulsation from the composite discharge flow rate in the discharge actually follows the completion in compression of the residual air represented by crosshatching in FIG. 8B. The pulsation of the composite discharge flow rate could not be removed.
The second proposal is to make a cam compensation for placing the cam in discharge allowable state prior to the actual discharge timing. The shape of the cam is compensated so that the pump discharge flow rate has a waveform represented by a real line in FIG. 9B. A compression corresponding to a volume, represented by a crosshatched portion in FIG. 9B, associated with the discharge flow rate is set prior to the actual discharge, for which reason on the discharge initiation stage the discharge have already been suitable due to including an extra discharge flow rate. Such extra discharge flow rate may, however, cause an increase in the composite discharge flow rate thereby the pulsation is generated as illustrated in FIG. 9.
The third proposal is to place the cam in discharge allowable state prior to the actual discharge timing so as to set the discharge flow rate at zero in the actual discharge initiation. The shape of the cams is compensated so that the discharge flow rate has a waveform represented by a real line in FIG. 10. A compression corresponding to a volume, represented by a crosshatched portion, of the pump discharge flow rate is set prior to the actual discharge so that the discharge has already been suitable on the discharge initiation stage. At the initiation of the discharge, the discharge flow rate is set at zero so that no extra discharge flow rate is generated thereby the composite discharge flow rate has no pulsation as illustrated in FIG. 10A. Namely, the shape of the cams may be compensated so that the pulsation is removed in the discharge initiation stage.
The influences due to the above second, third and fourth factors may be resolved by making the compensation in shape of the cams to obtain pulsation free flow. In other words, the pulsation may be removed only by compensation in the shape of the cams.
As described above, the convention pulsation free pump shows the reduction in the composite discharge flow rate in its initial stage due to the residual air in the hydraulic driving section, the liquid leakage in the air extraction process and the residual air in the pump operation section and others, for which reason the reduction would be unavoidable. The unavoidable reduction may be compensated by the extra discharge flow rate to ensure the desirable pulsation free discharge flow rate.
A magnitude of the reduction of the discharge flow rate depends upon the operation conduction of the pump system such as a discharge pressure and pipe lines, while a magnitude of the extra discharge flow rate is free from such condition. To ensure the pulsation free discharge flow rate, it is necessary to adjust an amount of the extra discharge flow rate for compensations for such variable reductions of the discharge flow rate due to the variable pump conditions.
In the conventional pulsation free pumps, the adjustment for ensuring the pulsation free discharge flow rate would substantially be impossible on the ground that the compensation in the shape of the cams would be restricted and a variation in an angular velocity is limited as being substantially defined by a stepping motor. Namely, the conventional cam shape compensation method is insufficient to exactly remove the pulsation from the discharge flow rate in response to largely variable pump operation conditions.
The conventional automatic air extraction hydraulic diaphragm pumps have a structure as illustrated in FIG. 11A. Inside a diaphragm pump body 40, there is provided a hydraulic chamber 44 and a pump chamber 46 which are separated by a diaphragm 42. The hydraulic chamber 44 is provided with plunger 48 penetrating the hydraulic chamber 44. The pump chamber 46 is provided with a suction port 54 and a discharge port 56 via check valves 50 and 52 respectively. A reciprocating operation of the plunger 48 causes a variation in pressure of the oil in the hydraulic chamber 44 thereby the diaphragm shows a pulse oscillation motion which allows the pump chamber 46 to show the pump operation.
On a top portion of the diaphragm pump body 40, an oil reservoir 58 is provided wherein an oil reserving chamber 60 within the oil reservoir 58 is connected to the above hydraulic chamber 44 through a multi-function valve 60a and an oil passage 64 provided in the oil reservoir 58 as well as through an oil passage 66 provided in the diaphragm pump body 40. As a result, the above multi-function valve 60a is so operated as to supplement the oil to the hydraulic chamber 44 when the hydraulic chamber 44 is deficient in oil due to operations of the plunger 48 and further to have the oil discharge from the hydraulic chamber 44 into the oil reservoir when the hydraulic chamber 44 has an excess of the oil. The above multi-function valve 60a is capable both of an air extraction for discharge of bubbles generated in the hydraulic chamber 44 by operations of the plunger 48 and of a supplement of a driving oil for compensation for a reduction thereof due to a leakage from the hydraulic chamber 44. Further, there is provided a safety valve 60b for allowing, in the hydraulic chamber 44, an escape of the excess of the oil pressure over a regulation valve.
There is further provided a piston pump 72 for driving a piston 70 via a cam 68 showing a rotation driving which is synchronized with a reciprocal motion of the plunger 48. The multi-function valve 60a is coupled to the piston pump 72 via the pump chamber 74 and an oil feeder pipe 76 to force the multi-function valve 60a to show opening and closing operations in association with the pump operation of the piston pump 72.
As illustrated in FIG. 11B, the above multi-function valve 60a has a valve body 80 within which there is formed a pressure chamber 82 which is coupled via an oil passage 84 to the oil feeder pipe 76 extending from the piston pump 72. On a top of the valve body 80, a flow rate adjuster 86 comprising an orifice is provided to introduce the oil in the oil reservoir 60 into the pressure chamber 82. A piston 88 is inserted into and supported by the pressure chamber 82 so that the piston 88 is fixed at an intermediate position of the pressure chamber 82. On the bottom of the valve body 80, there is formed a stem 90 into which inserted is a valve stem 94 which is closed by a spring 92. The valve stem 94 extends to penetrate the pressure chamber 82 and a portion thereof projecting from the pressure chamber is united with a valve section 98 having a tapered shape 96. The above multi-function valve 60a allows the oil to be fed discontinuously by the piston pump 72 to thereby generate a pressure difference when the pressured oil passes the orifice of the flow rate adjuster 86. The pressure difference may cause the piston 88 pressed down to have the stem 90 open for oil supplement into the hydraulic chamber 44 of the diaphragm pump body 40 together with an extraction of the air generated in the hydraulic chamber 44.
The above multi-function valve 60a may comprise a differential pressure automatic air extraction ball valve as illustrated in FIG. 12. In FIG. 12, the differential pressure automatic air extraction ball valve 30 is provided at its top portion with an adjusting nut 31, a valve body 34 with a seat 33 for a ball 32, and a bottom screw 35 engaged with the above adjusting nut 31 wherein the screw is inserted into the valve body 34. The valve 30 is further provided with an adjustable pipe 36 with a top seat 37 for the ball 32, and a stopper nut 38 engaged with the screw 35 of the above adjustable pipe 36.
The above differential pressure automatic air extraction ball valve 30 is so constructed that the ball 32 moves from top to bottom in the initiation of the pump suction process thereby a small amount of the oil flows from the oil reservoir 60 into the hydraulic chamber 44 and further the ball 32 moves from bottom to top in an initiation of the pump discharge process thereby a small amount of the oil together with an air in the hydraulic chamber 44 is discharged flow rate of the pressured oil is set larger than the suction flow rate since a pressure difference of the oils in discharge between inside the pump chamber 46 and an atmosphere is larger than that of the oil in suction.


This invention refers to a speed reducer made up of a chain carrying nuts and of a screw, i.e., a ball screw in the first embodiment, a roller screw in the second embodiment. The ball screw or the roller screw drives the nuts on one of the straight stretches of the chain. The ball screw, or the roller screw, can be almost as long as the distance between the centers of the output sprockets on which the chain is mounted. Given these features and because the nuts wrap the ball screw, or the roller screw in a great surface, the load capacity is high. Given that in both embodiments there is rolling contact, friction is low and, as a consequence, efficiency is high, and this allows the present invention to serve also as an amplifier.

The worm and gear speed reducer is one of the most frequently used when a large speed reduction is required. However, it has limitations: low load capacity and not a high efficiency. The low load capacity is inherent to the geometry since the pitch cylinder of the worm has only one point of tangency with the pitch cylinder of the gear and, therefore, with very few teeth in contact. The efficiency is not sufficiently high due to the sliding contact between the worm and the gear with the resulting loss of energy due to friction. The sliding contact also gives rise to rubbing that gives rise to wear. Furthermore, in some applications, the heat generated by friction is such that a cooling system is required and this involves a greater complication and higher manufacturing and maintenance costs.
During the preceding centuries several patents were granted referring to concepts to increase the load capacity of the worm and gear reducers by increasing the contact surfaces. The best known concepts to achieve this goal have been, on the one hand, a gear configuration with the circumferential toothed surface concave shaped so as to partially envelop or wrap the worm, and on the other hand, a worm with a concave silhouette which partially envelops the gear. Also, gear and worm assemblies are used with double enveloping arrangements, that is, which simultaneously incorporate both configurations. All of these schemes have contributed to noticeably raise the load capacity, but are still limited.
In 1897, the concept of a screw and chain speed reducer described in U.S. Pat. No. 595,508 by Wolander appeared, which refers to a speed reducer similar to a worm and gear, such as is shown in FIG. 1, but, instead of the gear, it has a transmission chain with threaded links with a small arc of contact with the screw thread. The turning of the screw drives the threaded links, and thus it also drives the chain which is mounted on two identical sprockets. Since the screw is in contact with said threaded links on the straight portion of the chain, the contact surface may be large, and therefore, the load capacity can be higher than that of the configurations described in the previous paragraph. However, since the motion transmission in all of these arrangements is carried out by means of sliding contact, the efficiency is low. The same can be said of patent DE 2406360, published in August 1975, by Werther, as well as patent JP2000-097293 by Hanaguchi Yuuji, published in April 2000, such as is shown in FIG. 2.
U.S. Pat. No. 418,328, published in December 1889 by Willett refers to a mechanism which drives a boat by means of pedals which includes an angular speed amplifier, made up of a chain equipped with small wheels that drive a "spiral B′", such as is shown in FIG. 3. In this case, the efficiency is raised by means of the small wheels and there is the potential to somewhat raise the load capacity but it is not really used, and neither is such possibility mentioned. The same is true for U.S. Pat. No. 594,511 published in November 1897, by Auble whose invention refers to a land vehicle.
U.S. Pat. No. 642,430 published in January 1900 by Corcoran, and DE 3305551 C2 published in September 1990 by Reguzzi, such as are shown in FIG. 4, as well as U.S. Pat. No. 7,222,682 published in May 2007 by Doering, such as is shown in FIG. 5, also refer to chains with small wheels, by which efficiency is raised, but there is also an increased load capacity compared to the patents described in the previous paragraph, because unlike them, all the rods in the chain have small wheels.
On the other hand, the patents: U.S. Pat. No. 626,515 published in June 1899, by Whitney and U.S. Pat. No. 747,463 published in December 1903, by Moore, such as are shown in FIG. 6, refer to worm and gear reducers which include small wheels in the gear to reduce friction and increase efficiency but, as has already been mentioned, this type of reducers have few teeth in contact with the consequent limitation on the load capacity.
In the past few decades there has been a general, great interest, in energy savings. Particularly, in the case of worm and gear speed reducers, patents have been granted, and applications continue to be filed which involve concepts to render them more efficient. Therefore, there are patents, for example, U.S. Pat. No. 4,023,433 published on May 9, 1977, by Schutz, such as can be seen in FIG. 7a; and U.S. Pat. No. 7,051,610 published on May 2006, by Stoianovici, such as can be seen in FIG. 7b, which refer to an assembly of balls that roll between the worm thread and the gear teeth, circulating in a closed circuit, that is to say, that once they have journeyed through the entire helicoid thread, they return through an ad hoc conduit to return and re-journey said thread. Of course, the threads are designed in such a way so as to aid in the transit of the balls. In this manner, the sliding contact between the worm and the gear is substituted by a rolling contact which lowers the friction coefficient thereby decreasing the losses and, consequently, increasing the efficiency. In these patents, the gear partially envelops the worm and the worm partially envelops the gear in order to somewhat increase the load capacity, but within the limit imposed by the geometry of the worm and gear assembly, as has been discussed above.
Other patents which could be considered generally relevant in prior art, as far as the roller screw which is applied in the second embodiment of the present invention, are patents U.S. Pat. No. 2,683,379, published in July 1954, by Strandgren, and U.S. Pat. No. 8,082,818, published in December 2011, by Sugitani. However, these patents do not describe a reducer. The conventional roller screw is driven by a tube which has an internal thread, and in the case of the inverted roller screw, said tube is driven by the screw. However, for the sake of simplicity, the inverted roller screw which is used in the second embodiment of the present invention will be simply called "roller screw". This term refers to an assembly, which basically consists of a worm provided with threaded planetary rollers, and placed within an internally threaded tube. The threaded planetary rollers roll between the worm and the threaded tube, and upon turning they displace said tube on a straight line. In the present invention, the internally threaded tube is substituted by a plurality of nuts which are mounted on the links of a chain transmission.