The present invention is a pressure-sensitive adhesive tape or sheet prepared by laminating a pressure-sensitive adhesive layer onto one side of an urethane resin layer consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570, wherein the aforementioned A is represented by the following equation

The present invention is related to a pressure-sensitive adhesive tape or sheet which has superior conformability onto a substrate, easy-tear properties, and coloring properties.
So called xe2x80x9cvinylxe2x80x9d tape, which is prepared by laminating a pressure-sensitive adhesive layer on one side of a soft vinyl chloride resin base material, is superior in terms of flexibility, conformability onto a substrate, easy-tear properties, electric insulation, etc., and can easily be colored and weather-proofed as necessary, and therefore is widely used in applications such as electric insulation tapes, anticorrosion tapes, sealing tapes, marking sheets, etc.
Of these, marking sheets are widely used in sign boards, advertisement boards, shutters, and advertising stickers used on windows and such; ornamental stripe stickers used on automobiles, motor bikes, motor boats, snowmobiles, etc.; and display stickers used on traffic signs, directory boards, etc. Since conformability onto unevenness and curved surfaces of a substrate and lack of shrinking over time are required, the base material is prepared by adding a plasticizer, pigment and such to vinyl chloride resin, followed by molding with typically the calender method, and with the cast method for marking sheets and such which require superior quality in terms of weather resistance and strength (Japanese examined patent publication Tokko Hei 5-88862, for example).
However, since vinyl chloride resin contains chlorine, dioxine is produced when it is incinerated after use, resulting in environmental health problems. Therefore, a pressure-sensitive adhesive tape or sheet which uses resin containing no chlorine as the base material and yet possesses the same qualities as xe2x80x9cvinylxe2x80x9d tapes is desired.
For example, Japanese unexamined patent publication Tokkai Hei 3-45672 discloses a marking film which uses polyurethane film as the base material. However, since the isocyanate component used in the aforementioned polyurethane film is diisocyanate with a short distance between isocyanate groups, such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate, the flexibility was insufficient and the conformability onto unevenness and curved surfaces of a substrate was also insufficient.
Tokkai Hei 8-20750 discloses a marking film whose base material is a polypropylene-based resin with a weight average molecular weight of 80,000-500,000 for which, based on the cross fractionation method, the eluted amount for 0xc2x0 C. or higher and 10xc2x0 C. or lower is 45-80 wt % of the total resin amount, the eluted amount for temperatures higher than 10xc2x0 C. and 70xc2x0 C. or lower is 5-35 wt % of the total resin amount, the eluted amount for temperatures higher than 70xc2x0 C. and 95xc2x0 C. or lower is 1-30 wt % of the total resin amount, and the eluted amount for temperatures higher than 95xc2x0 C. and 125xc2x0 C. or lower is 3-35 wt % of the total resin amount. This polypropylene-based resin is too soft, does not provide glossy film, and the obtained film has the shortcoming of being difficult to cut. Also, its weather resistance is low; it can be used for only two years even when a stabilizer is added.
In view of the aforementioned shortcomings, the objective of the present invention is to provide a pressure-sensitive adhesive tape or sheet which is flexible, superior in terms of the conformability onto a substrate, and superior in easy-tear properties, as well as a method for manufacturing such tape or sheet.
Another objective is to provide a pressure-sensitive adhesive tape or sheet which is superior in terms of coloring properties, weather resistance and such, and can be used preferably as marking tapes or sheets, as well as a method for manufacturing such tape or sheet.
The first of the present invention is a pressure-sensitive adhesive tape or sheet prepared by laminating a pressure-sensitive adhesive layer onto one side of an urethane resin layer consisting of 100 weight parts of a polyol. component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570, wherein the aforementioned A is represented by the following equation
xe2x80x83A=100aX/Y
(in this equation, a is a constant 0.067-0.135, X is the hydroxide value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component), and, at 5xc2x0 C. and 35xc2x0 C., the strength at a 2% elongation is 0.40-2.20 Kg/15 mm-width and the breaking elongation is 50-300%.
The second of the present invention is a pressure-sensitive adhesive tape or sheet prepared by laminating one after another a urethane resin layer consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570, an olefin-based resin layer, and a pressure-sensitive adhesive layer, wherein the aforementioned A is represented by the following equation
A=100aX/Y
(in this equation, a is a constant. 0.067-0.135, X is the hydroxide value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component), and, at 5xc2x0 C. and 35xc2x0 C., the strength at a 2% elongation is 0.40-2.20 Kg/15 mm-width and the breaking elongation is 50-300%.
The third of the present invention is a method of manufacturing the pressure-sensitive adhesive tape or sheet of the first of the present invention which comprises a process in which the first lamination is obtained by laminating a pressure-sensitive adhesive layer onto one side of the first release film, a process in which the second lamination is obtained by applying a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570 and solvent onto the second release film, followed by drying, thus forming a urethane resin layer with a cross-link ratio of 20-93% on one side of the second release film, and a process in which the first lamination and the second lamination are laminated together in such a way that the pressure-sensitive adhesive layer of the first lamination and the urethane resin layer of the second lamination contact each other and the reaction of the urethane resin is completed, wherein the aforementioned A is represented by the following equation
A=100aX/Y
(in this equation, a is a constant 0.067-0.135, X is the hydroxide value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component.)
The fourth of the present invention is a method of manufacturing the pressure-sensitive adhesive tape or sheet of the second of the present invention which comprises a process in which the first a lamination is obtained by laminating a pressure-sensitive adhesive layer and then the first release film onto an olefin-based resin layer, a process in which the second lamination is obtained by applying a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570 and solvent onto the second release film, followed by drying, thus forming a urethane resin layer with a cross-link ratio of 20-93% on one side of the second release film, and a process in which the first lamination and the second lamination are laminated together in such a way that the olefin-based resin layer of the first lamination and the urethane resin layer of the second lamination contact each other and the reaction of the urethane resin is completed, wherein the aforementioned A is represented by the following equation
A=100aX/Y
(in this equation, a is a constant 0.067-0.135, X is the hydroxide value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component.)
The fifth of the present invention is a method of manufacturing the pressure-sensitive adhesive tape or sheet of the second of the present invention which comprises a process in which the first lamination is obtained by laminating a pressure-sensitive adhesive layer and then the first release film onto an olefin-based resin layer, and a process in which a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component with a distance between cross-links (weight average molecular weight/number of isocyanate groups) of 220-570 and solvent is applied onto the aforementioned olefin-based resin layer, followed by drying, to form a urethane resin layer with a cross-link ratio of 20-93%, the second release film is then laminated onto said urethane resin layer, and the reaction of the urethane resin is completed, wherein the aforementioned A is represented by the following equation
A=100aX/Y
(in this equation, a is a constant 0.067-0.135, X is the hydroxide value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component.)
The first of the present invention is a pressure-sensitive adhesive tape or sheet (hereafter referred to as xe2x80x9cpressure-sensitive adhesive sheetxe2x80x9d) with specific mechanical properties prepared by laminating a pressure-sensitive adhesive layer onto one side of a urethane resin layer consisting of a polyol component and polyisocyanate component.
For the aforementioned polyol component, any polyol which has two or more hydroxyl groups and reacts with a polyisocyanate component to produce urethane resin, and has been conventionally used as the raw material of urethane resin, can be used. Examples include polyether polyol, polyester polyol, and acryl polyol. Acryl polyol is preferably used because of its superior paint film adhesion, chemical resistance, weather resistance, etc.
The preferable acryl polyol is a copolymer of alkyl (meth)acrylate and hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. For the aforementioned alkyl (meth)acrylate, alkyl (meth)acrylate which has an alkyl group having 12 or less carbon atoms is preferable. Examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, isononyl (meth)acrylate, and lauryl (meth)acrylate. They can be copolymerized independently, or in combinations of two or more.
Also, as necessary, monomers which can be copolymerized with the aforementioned hydroxyl group-containing (meth)acrylate and alkyl (meth)acrylate, including monomers such as styrene, vinyl acetate, vinyl propionate, (meth)acrylonitrile, and N-vinylpyrrolidone, as well as monomers with polar groups such as (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, and (meth)acrylamide, can also be copolymerized. Two or more copolymers can be used as necessary.
For the glass transition temperature (Tg) of the polyol component, if it is low then the urethane resin becomes soft and its mechanical strength decreases, and on the other hand, if it is high then the resin becomes brittle: A preferable range is 0-100xc2x0 C., and a more preferable range is 30-80xc2x0 C.
For the hydroxyl group value of the polyol if component, if it is low then the cross-link density of the obtained urethane resin becomes low, resulting in softening and a reduction in mechanical strength. On the other hand, if it is high the cross-link density becomes high and the urethane resin becomes brittle. Therefore, the preferable range is 20-150.
In the present invention, the hydroxyl group value is defined as the amount of potassium hydroxide (mg) required to neutralize the acetic acid which is bonded to the acetylated substance obtained from 1 g of the polyol component.
The weight average molecular weight of the polyol component is not limited in particular, as long as the component meets the aforementioned Tg and hydroxyl group value conditions and can be dissolved in the solvent. A general range is 1,000-500,000.
The aforementioned polyisocyanate component is a polyisocyanate which has two or more isocyanate groups in the molecule and reacts with the polyol component to form urethane resin. Polyisocyanate with a distance between cross-links of 220-570 is used for this. The distance between cross-links of polyisocyanate is defined as the weight average molecular weight of polyisocyanate divided by the number of the isocyanate (NCO) groups in the polyisocyanate. If two or more polyisocyanates are used, the weighted arithmetic average of the distances between cross-links of the polyisocyanates is used.
The larger the distance between cross-links of polyisocyanate, the wider the interval between cross-linked polyols, and the obtained urethane resin becomes softer. The smaller the distance between cross-links, the narrower the interval, and the obtained urethane resin becomes harder and more brittle. Therefore, a polyisocyanate with a distance between cross-links adjusted to 220-570 is used, and more preferably a polyisocyanate with a distance between cross-links of 250-550 is used.
Examples of polyisocyanates with a distance between cross-links of less than 220 include diisocyanates such as tolylene diisocyanate (TDI) 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate, and tetramethylxylene diisocyanate; the trimethylolpropane adduct of diisocyanate; the biuret of diisocyanate; the isocyanurate of diisocyanate, as well as condensated forms of these. Mixtures can be used as well. An example of a commercially available polyisocyanate with a distance between cross-links of less than 200 is Sumijule N3200 (trade name) from Sumitomo Bayer Urethane Co., Ltd. (mainly the biuret yielded from HDI, in which the solid content is 100 wt %, weight average molecular weight 670, number of isocyanate groups 3.7, distance between cross-links 181, and isocyanate group content 23.0 wt %).
Preferable examples of polyisocyanates with a distance between cross-links of 220-570 include the aforementioned trimethylolpropane-adduct of diisocyanate, a compound prepared by adding diisocyanate prepolymerized with polyester diol to trimethylolpropane, polyester diol- or polyester polyol-adducts of diisocyanate, the biuret of diisocyanate, and the isocyanurate of diisocyanate, as well as their condensated forms or mixtures.
Examples of commercially available polyisocyanates with a distance between cross-links of 220-570 are listed below.
For example, Sumijule HT (trade name, from Sumitomo Bayer Urethane Co., Ltd.) is an ethyl acetate solution of mainly an HDI adduct of trimethylolpropane (solid content 75 wt %, weight average molecular weight 1, 100, number of isocyanate groups 4.5, distance between cross-links 244, and isocyanate group content 13.0 wt %); Coronate HL (trade name, from Nippon Polyurethane Industries Co., Ltd.) is an ethyl acetate solution of mainly HDI adduct of trimethylolpropane (solid content 75 wt %, weight average molecular weight 850, number of isocyanate groups 3.4, distance between cross-links 250, and isocyanate group content 12.8 wt %); and
Coronate HLS (trade name, from Nippon Polyurethane Industries Co., Ltd. is an ethyl acetate solution of mainly the cross-linked lacton ester of the aforementioned Coronate HL (solid content 75 wt %, weight average molecular weight 900, number of isocyanate groups 2.3, distance between cross-links 391, and isocyanate group content 10.0 wt %).
Additional examples include Desmodule E3265 (trade name, from Sumitomo Bayer Urethane Co., Ltd.) and Duranate E-402 (trade name, from Asahi Chemical Industry Co., Ltd.).
Examples of polyisocyanates with a distance between cross-links larger than 570 include Desmodule TPLS 2010/1 (trade name, from Sumitomo Bayer Urethane Co., Ltd.). This is polymerized HDI (solid content 100 wt %, weight average molecular weight 1,540, number of isocyanate groups 2.6, distance between cross-links 592, and isocyanate group content 10.4 wt %).
The urethane resin layer consists of 100 weight parts of the polyol component and A weight parts of the polyisocyanate component, where A is represented by the following equation.
A=100aX/Y
In this equation, a is a constant 0.067-0.135, X is the hydroxide group value of the aforementioned polyol component, and Y is the weight percent concentration of isocyanate groups in the polyisocyanate component.
Urethane resin is formed by the reaction between the hydroxide groups of the polyol component and the isocyanate groups of the polyisocyanate component. If the isocyanate groups are few (if the amount of the added polyisocyanate component is small), then the cross-link density becomes low and there are many residual hydroxide groups, resulting in a soft and/or sticky urethane resin layer with insufficient mechanical strength. On the other hand, if there are many isocyanate groups (if the amount of the added polyisocyanate component is larger), the cross-link density becomes high, resulting in a reduction in deformation-conformability and excessive residual isocyanate groups, which contribute to changes in the mechanical strength over time. Therefore, the polyisocyanate component is added within the range mentioned above, and a preferable range of a is 0.075-0.125.
For the aforementioned pressure-sensitive adhesive, any prior art pressure-sensitive adhesive can be used, such as acryl-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicon-based pressure-sensitive adhesives, and urethane-based pressure-sensitive adhesives. When the pressure-sensitive adhesive sheet of the present invention is used as a marking sheet, since it will mostly be used outdoor, acryl-based pressure-sensitive adhesives, which have superior weather resistance, are preferable.
The form of the pressure-sensitive adhesive is not limited in particular; any prior art pressure-sensitive adhesive such as the solvent types, emulsion types, and hot-melt types can be used.
The pressure-sensitive adhesive sheet of the present invention is formed by laminating the pressure-sensitive adhesive layer on one side of the aforementioned urethane resin layer. For the thickness of urethane resin, if it is thin then the sheet becomes soft and loses stiffness, which makes handling difficult. If it is thick then the sheet becomes hard and the conformability into a substrate is reduced, which makes pasting difficult. Therefore, a preferable range is 30-120 micrometers, and a more preferable range is 40-100 micrometers.
The thickness of the pressure-sensitive adhesive layer should be such that the pressure-sensitive adhesive sheet can be pasted onto the substrate firmly enough. Generally, the thickness is 10-80 micrometers, and preferably 20-50 micrometers.
Therefore, the thickness of the pressure-sensitive adhesive sheet is preferably 40-200 micrometers, and more preferably 60-150 micrometers.
For the mechanical properties of the pressure-sensitive adhesive sheet of the present invention, at 5xc2x0 C. and 35xc2x0 C. the strength at a 2% elongation must be 0.40-2.20 Kg/15 mm-width and the breaking elongation must be 50-300%.
As a pressure-sensitive adhesive sheet is being pasted onto a substrate while the sheet is stretched a little so it can follow the substrate""s shape, if the elongation strength is too weak, then the sheet stretches more than necessary and pasting becomes difficult. On the other hand, if the elongation strength is too strong, stretching the sheet becomes hard and thus making the sheet conform to the substrate""s shape becomes hard; even if pasting can be done, peeling and separation tend to occur over time. Therefore, the strength at a 2% elongation must be 0.40-2.20 Kg/15 mm-width, preferably 0.50-2.10 Kg/15 mm-width, at normal temperatures, i.e. 5xc2x0 C., and 35xc2x0 C.
The method for measuring the strength at 2% elongation in the present invention is as follows. A 15 mm-wide pressure-sensitive adhesive sheet is held at 100 mm intervals and pulled at a pulling rate of 200 mm/minute. The stress at 2% elongation is measured.
For the breaking elongation, if it is small then breaking may result due to stretching during pasting or due to an impact; if it is too large, then cutting becomes difficult. Therefore, it has to be in the range of 50-300%, preferably 70-250%.
The method for measuring the breaking elongation in the present invention is as follows. A 15 mm-wide pressure-sensitive adhesive sheet is held at 100 mm intervals and pulled at a pulling rate of 200 mm/minute until it breaks. The length of elongation at the time of breaking is expressed as a ratio (%) compared with the original length of the pressure-sensitive adhesive sheet.
For the residual stress of the pressure-sensitive adhesive sheet, if a significant residual stress remains after stretched pasting, then the chance of separation and/or peeling over time increases. Therefore, the residual stress ratio ten minutes after 10% stretching should preferably be 60% or less.
The method for measuring the residual stress in the present invention is as follows. A 15 mm-wide pressure-sensitive adhesive sheet is held at 100 mm intervals, and pulled at a pulling rate of 200 mm/minute until the elongation is 10%, at which time the sheet is held as it is; ten minutes later the residual stress is measured and expressed as a ratio (%) in relation to the stress at the time of 10% elongation.
The second of the present invention is a pressure-sensitive adhesive sheet which consists of an olefin-based resin layer laminated between the urethane resin layer and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the first of the present invention.
For the aforementioned olefin-based resin, any conventional prior art olefin-based resin including a polyethylene resin, polypropylene resin, ethylene-propylene copolymer, copolymer of ethylene or propylene and xcex1-olefin such as butene-1, pentene-1, hexene-1, heptene-1, octene-1,4-methyl-1-pentene, etc., ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, etc. can be used.
When the olefin-based resin layer is laminated, the mechanical properties of the pressure-sensitive adhesive sheet are mostly governed by the mechanical properties of the olefin-based resin layer. Since the mechanical properties of the pressure-sensitive adhesive sheet are as described above, the mechanical properties of the olefin-based resin layer should preferably be in the range described below.
That is, at 5xc2x0 C. and 35xc2x0 C., the strength at a 2% elongation is preferably 0.40-2.10 Kg/15 mm-width and the breaking elongation is preferably 100% or more. If a significant residual stress remains after stretched pasting, then the chance of separation and/or peeling over time increases. Therefore, the residual stress ratio ten minutes after 10% stretching should preferably be 60% or less.
The olefin-based resin to form the aforementioned olefin-based resin layer should preferably be a polypropylene-based resin with a weight average molecular weight of 80, 000-500,000 for which, based on the cross fractionation method, the eluted amount at 0xc2x0 C. is 30-70 wt % of the total resin amount, the eluted amount at temperatures higher than 0xc2x0 C. and 70xc2x0 C. or lower is 5-30 wt % of the total resin amount, and the eluted amount at temperatures higher than 70xc2x0 C. is 20-60 wt % of the total resin amount (hereafter referred to as xe2x80x9cpolypropylene-based resin (A)xe2x80x9d)
For the weight average molecular weight, if it is small then the film strength decreases; if it is large then the flexibility decreases. Therefore, a preferable range is 80,000-500,000, and a more preferable range is 200,000-400,000. In the cross fractionation method, soft resin elutes at lower temperatures; the higher the temperature, the harder the eluted resin. Therefore, polypropylene-based resin which exhibits the aforementioned ranges of resin elution is preferable.
In the second of the present invention, the a cross fractionation method is as follows. The polypropylene-based resin to be measured is first dissolved into o-dichlorobenzene at 140xc2x0 C. or the temperature at which it completely dissolves and then cooled at a constant rate. Thin resin layers are formed on an inert carrier surface, with layer s with higher levels of crystallization and higher molecular weights deposited first. The temperature is then raised from 0xc2x0 C. continuously or step-wise to elute the o-dichlorobenzene, and finally the concentration of the eluted resin is detected to measure the elution distribution of the resin by temperature.
In order to adjust the strength at a 2% elongation and the breaking strength of the aforementioned olefin-based resin layer, a polypropylene-based resin with a weight average molecular weight of 80,000-500,000 for which, based on the cross fractionation method, the eluted amount at 0xc2x0 C. is 0-20 wt % of the total resin amount, the eluted amount at temperatures higher -than 0xc2x0 C. and 70xc2x0 C. or lower is 5-30 wt % of the total resin amount, and the eluted amount at temperatures higher than 70xc2x0 C. is 70-90 wt % of the total resin amount (hereafter referred to as xe2x80x9cpolypropylene-based resin (B)xe2x80x9d) can be used in addition to polypropylene resin (A).
For polypropylene-based resin (B), the eluted amount at temperatures higher than 70xc2x0 C. is 70-90 wt % of the total resin amount, which is high; i.e. it is a harder and mechanically stronger resin compared with polypropylene resin (A). Therefore, adding a larger amount of this resin results in an olefin-based resin with a higher strength at a 2% elongation, a smaller breaking elongation, and a higher residual stress ten minutes after 10% elongation. Preferable ranges are 100-30 wt % for polypropylene-based resin (A) and 0-70 wt % for polypropylene-based resin (B).
The pressure-sensitive adhesive sheet of the second of the present invention is the same as the pressure-sensitive adhesive sheet of the first of the present invention in terms of the configuration of the urethane resin layer and pressure-sensitive adhesive layer and physical properties such as the strength at a 2% elongation, the breaking elongation, and residual stress ratio.
The pressure-sensitive adhesive sheet of the second of the present invention comprises the aforementioned olefin-based resin layer onto one side of which a urethane resin layer is laminated and onto the other side of which a pressure-sensitive adhesive layer is laminated. If the olefin-based resin layer is thin then the stiffness is lost, resulting in difficult handling. If it is thick, then the sheet becomes hard and the conformability onto a substrate""s shape deceases, resulting in difficult pasting. Therefore, a preferable range is 20-80 micrometers, and a more preferable range is 30-70 micrometers.
If the urethane resin layer is thin then the sheet becomes soft and loses its stiffness, resulting in difficult handling. If it is thick then the sheet becomes hard and the conformability onto a substrate""s shape deceases, resulting in difficult pasting. Therefore, a preferable range is 5-50 micrometers, and a more preferable range is 10-30 micrometers. Therefore, the total thickness of the olefin-based resin layer and the urethane resin layer is preferably 25-130 micrometers, and more preferably 40-100 micrometers.
The thickness of the pressure-sensitive adhesive layer should be such that the pressure-sensitive adhesive sheet can be pasted onto a substrate with sufficient strength. A general range is 10-80 micrometers, and a preferable range is 20-50 micrometers.
Therefore, the thickness of the pressure-sensitive adhesive sheet is preferably 35-210 micrometers, and more preferably 50-150 micrometers.
Each layer of the pressure-sensitive-adhesive sheet of the present invention can be colored by adding a coloring agent. In particular, when the pressure-sensitive adhesive sheet is used as a marking tape or sheet (hereafter referred to as xe2x80x9cmarking sheetxe2x80x9d), it must be colored. The coloring agent should preferably be added to the urethane resin layer.
For the aforementioned coloring agent, any coloring agent used for coloring resins, paints, etc. can be used. Examples include dyes such as azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, and carbonium ion dyes; inorganic pigments such as calcium carbonate, barium sulfate, zinc oxide, titanium oxide, chrome yellow, cadmium yellow, nickel titanium yellow, iron oxide red, cadmium red, molybdenum orange, Berlin blue, ultramarine blue, and carbon black; and organic pigments such as azo-based pigments, phthalocyanine-based pigments, metal complex salt-based pigments, triphenylmethane-based pigments, quinaclidone-based. pigments, and isoindolinone-based pigments. These coloring agents can be used independently or in combinations of two or more.
The amount of the aforementioned coloring agent to be added can be determined as necessary. Generally, it is preferable to add 0.1-70 weight parts for 100 weight parts of the urethane resin.
In addition, photo stabilizers, ultraviolet light absorbents, antioxidants, anti static additives, and antiblocking additives can be added to each layer as necessary.
Examples of the aforementioned photo stabilizers include poly[{6-(1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], succinic acid dimethyl-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetr amethylpiperidine condensation polymer, and bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, which are hindered amine-based photo stabilizers. These photo stabilizers are commercially available from Ciba Specialty Chemicals K. K. with the trade names of Chimasorb 944, Tinuvin 622, and Tinuvin 123, respectively.
When adding the aforementioned photo stabilizers, it is preferable to use the so called NR type, whose amine groups have their hydrogen replaced and nitrogen bonded to an alkyl group or the main chain, and the so called NOR type, whose amine groups have their hydrogen replaced and nitrogen bonded to an alkyl group or the main chain through oxygen. Tinuvin 622 and Tinuvin 123 are preferably used.
Examples of the aforementioned ultraviolet light absorbents include benzotriazole-based ultraviolet light absorbents such as Tinuvin 327 and Tinuvin 328 (trade names) from Ciba Specialty Chemicals K.K., benzophenone-based ultraviolet light absorbents such as Chimasorb 81 (trade names-) from Ciba Specialty Chemicals K.K., and triazine-based ultraviolet light absorbents such as Tinuvin 900 (trade names) from Ciba Specialty Chemicals K.K.
Examples of the aforementioned antioxidants include hindered phenol-based antioxidants such as Irganox 1010 and Irganox 1076 (trade names) from Ciba Specialty Chemicals K.K. and phosphorus-based antioxidants such as Adekastab PEP8 (trade name) from Asahi Denka Kogyo K.K.
Examples of the aforementioned antistatic additives include surfactants such as anionic surfactants, cationic surfactants, ampholytic surfactants, and non-ionic surfactants, and electrically conductive powder such as carbon black.
Examples of the aforementioned antiblocking additives include inorganic fine powder such as silica and alumina, as well as glass beads and silicone fine particles.
The method for manufacturing the pressure-sensitive adhesive sheet of the first and second (claims) of the present invention is not limited in particular, and any prior art method can be used. It is preferable to use the methods of manufacturing the pressure-sensitive adhesive sheet of the third to fifth (claims) of the present invention as described below.
The third of the present invention is a method of manufacturing the pressure-sensitive adhesive sheet of the first of the present invention. This method comprises a process in which the first lamination is obtained by laminating a pressure-sensitive adhesive layer onto one side of the first release film, a process in which a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component and solvent is applied and dried onto the second release film to obtain the second lamination consisting of a urethane resin layer with a cross-link ratio of 20-93% on one side of the second release film, and a process in which the first lamination and the second lamination are laminated together in such a way that the pressure-sensitive adhesive layer of the first lamination and the urethane resin layer of the second lamination contact each other and the reaction of the urethane resin is completed.
The process for obtaining the aforementioned first lamination is a process of forming a pressure-sensitive adhesive layer on one side of the first release film. For the aforementioned first release film, any release film which is commonly used for release film for pressure-sensitive adhesive sheets, pressure-sensitive adhesive labels, etc. can be used. Examples include polyethylene laminated paper consisting of polyethylene laminated on a base paper material such as high quality paper and craft paper; clay coated paper consisting of clay laminated on a base paper material such as high quality paper and craft paper; glassine paper super calendered paper; and release film consisting of a silicone-based release agent, alkyl pendant-based release agent, fluoride-based release agent, etc. laminated on a base material such as a plastic film, e.g. a polyethylene terephthalate film, a oriented polypropylene film, or a polyethylene film.
Also, any prior art method can be used to form the pressure-sensitive adhesive layer. For example, a method in which the pressure-sensitive adhesive is applied onto the release film and then dried can be used for the solvent types or the emulsion types of pressure-sensitive adhesive; and a method in which the pressure-sensitive adhesive is melted and extruded onto the release film to form a lamination can be used for the hot melt type pressure-sensitive adhesives.
The process of obtaining the aforementioned second lamination is a process of applying a reactive resin composition onto the second release film, followed by drying, to form a urethane resin layer with a cross-link ratio of 20-93% on one side of the second second release film.
The aforementioned reactive resin composition consists of 100 weight parts of the polyol component and A weight parts of the polyisocyanate component. When so called xe2x80x9cblock typexe2x80x9d, in which isocyanate is blocked with alcohol or derivatives such as phenol and cyclohexane oxime, is not used, the reaction between the polyol component and the polyisocyanate component proceeds quickly after they are mixed. Therefore, it is preferable to prepare the polyol solution and polyol solution separately, mix them to obtain the reactive resin composition, and then apply it onto the second second release film, followed by drying.
For the aforementioned solvent, any solvent can be used which dissolves the polyol component and the polyisocyanate component. Examples include ethyl acetate, toluene, xylene, butyl acetate, isobutyl acetate, and methylisobutylketone. Mixed solvent can also be used. Commercially available products include Sorbesso (trade name: from Exxon Chemical Ltd.).
The concentration of the polyol solution can be chosen as appropriate. 25-100% is preferable. However, since the polyol component has a high molecular weight (a low molecular weight would result in reduced weather resistance of the base material), a high concentration would mean a high viscosity and difficulty in mixing and applying. Therefore, a solid content of 25-100% is preferable.
If a coloring agent, photo stabilizer, ultraviolet light absorbent, antioxidant, etc. are to be added, it is preferable to add them to the polyol solution and dissolve or disperse them before mixing.
Catalysts which are commonly used when manufacturing urethane resins can be used to adjust the reaction rate between the polyol component and the polyisocyanate component. Examples of such catalysts include amine-based catalysts such as triethylamine, triethylenediamine, and dimethylamino ethanol, tin-based catalysts such as dibutyl tin laurate and dioctyl tin dilaurate, zinc-based catalysts, and lead-based catalysts.
The amount of the catalyst to be added can be chosen as necessary. Generally, 0.05-1.0 weight parts is used for 100 weight parts of the total amount of the polyol component and the polyisocyanate component.
Cross-linking of the reactive resin composition applied onto the second release film takes some time. Therefore, a preferable procedure is as follows: in the beginning, the composition is dried at a temperature lower than its boiling point with plenty of air flow so that the solvent does not boil and bubble; after the solvent is evaporated to a certain extent, the. composition is then heated to a temperature higher than the boiling point to accelerate the cross-linking process and reduce the amount of the residual solvent.
The reaction rate of the reactive resin composition slows down as the reaction proceeds. Therefore, when the urethane resin layer with a cross-link ratio of 20-93% is formed on one side of the second release film, the first lamination and the second lamination are laminated together such that the pressure-sensitive adhesive layer of the first lamination and the urethane resin layer of the second lamination contact each other to obtain a four-layer lamination consisting of the first release film, the pressure-sensitive adhesive layer, the urethane resin layer and the second release film laminated together, and then the urethane resin reaction is completed. To complete the urethane resin reaction, curing at 10-60xc2x0 C. should be carried out for 1-10 days.
The aforementioned cross-link ratio is defined as follows. The urethane resin is fed into a shaker, swollen and dissolved in ethyl acetate at 23xc2x0 C. for 24 hours. After filtering with a 200-mesh metal screen, the ratio of the residue on the screen and the original urethane resin (in wt % unit) is defined as the cross-link ratio.
As described above, the reaction rate of the reactive resin composition slows down as the reaction proceeds. Therefore, a large amount of heat and a large amount of time are required to complete the reaction of the reactive resin composition continuously during the manufacturing process, resulting in poor productivity. However, the aforementioned process allows for productive manufacturing.
Selection of the aforementioned second release film is not limited in particular, and the release film used for the aforementioned first release film, as described above, can be used. Since the physical adhesiveness of the urethane resin (reactive resin composition) is lower than that of the pressure-sensitive adhesive, films that do not react with the isocyanate groups of the urethane resin layer (reactive resin composition) and have a low polarity can be used; examples include plastic films such as polypropylene film, polyethylene terephthalate film, and polyethylene film, as well as their drawn films.
The aforementioned second release film is so-called release film, and it is peeled off before or after pasting the pressure-sensitive adhesive sheet onto a substrate. If the adhesiveness between the urethane resin layer after completion of the reaction and the second release film is weaker, separation occurs between the urethane resin layer and the second release film when the aforementioned four-layer lamination is transported, wound up for curing and storage, or treated for secondary processing, which results in poor appearance of the urethane resin layer. On the other hand, if the adhesive is strong, then peeling off the second release film is harder, and the second release film may break, and/or peels discontinuously to leave step marks on the urethane resin layer, resulting in poor appearance.
Therefore, the second release film should preferably be release film which, after completion of the urethane resin reaction, has a 180-degree peeling strength of 5-200 g/50 mm-width as measured at a peeling rate of 300 mm/minute. xe2x80x9cAfter completion of the urethane resin reactionxe2x80x9d means immediately following 24-hour curing at 40xc2x0 C. after the four-layered lamination is obtained.
The urethane resin becomes the surface layer when the obtained pressure-sensitive adhesive sheet is pasted onto a substrate. If the pressure-sensitive adhesive sheet is used as a marking sheet, a designed external appearance may be required. In the aforementioned manufacturing method, the urethane resin is applied and dried onto the second release film as the reactive resin. composition, and the second release film is peeled after completion of the reaction of the urethane resin; therefore, the surface configuration of the second release film is transcribed onto the urethane resin layer. Because of this, it is preferable to use smooth release film when the surface of the urethane resin layer is required to be smooth, and to use release film with treated with a roughing process such as a matting process, roll process, or sandblast process when the surface of the urethane resin layer is required to be matted.
The fourth of the present invention is a method of manufacturing the pressure-sensitive adhesive sheet of the second of the present invention. This method comprises a process in which the first lamination is obtained by laminating a pressure-sensitive adhesive layer and then the first release film onto one side of the olefin-based resin layer, a process in which a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component and solvent is applied and dried onto the second release film to obtain the second lamination consisting of a urethane resin layer with a cross-link ratio of 20-93% on one side of the second release film, and a process in which the first lamination and the second lamination are laminated together in such a way that the olefin-based resin layer of the first lamination and the urethane resin layer of the second lamination contact each other and the reaction of the urethane resin is completed.
The process for obtaining the aforementioned first lamination is a process of forming a pressure-sensitive adhesive layer and then the first release film on one side of the olefin-based resin layer. How each layer should be formed is not limited in particular, and any method can be used, examples of which include the following:
(1) a method in which the olefin-based resin and a hot melt type pressure-sensitive adhesive are coextruded and then the first release film is laminated onto the pressure-sensitive adhesive sheet,
(2) a method, as described in the third of the present invention, in which the pressure-sensitive adhesive is formed on the first release film, and then the olefin-based resin film which was formed separately is placed on top, and
(3) a method in which the olefin-based resin film is prepared first, the pressure-sensitive adhesive sheet is laminated onto one side of it, and then the first release film is placed on top.
The process in which the aforementioned second lamination is obtained is the same as the process by which the second lamination is obtained in the third of the present invention. Except for the fact that the first lamination and the second lamination are laminated such that the olefin-based resin layer and the urethane resin layer of the second lamination contact each other, the reaction of the urethane resin is completed in the manner described in the third of the present invention.
The fifth of the present invention is a method of manufacturing the pressure-sensitive adhesive sheet of the second of the present invention. This method comprises a process in which the first lamination is obtained by laminating a pressure-sensitive adhesive layer and then the first release film onto one side of the olefin-based resin layer, and a process in which a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component and solvent is applied and dried onto the aforementioned olefin-based resin layer to form a urethane resin layer with a cross-link ratio of 20-93% and then the second release film is laminated onto said urethane resin layer, followed by completion of the reaction of the urethane resin.
The process in which the aforementioned first lamination is obtained is the same as the process by which the first lamination is obtained in the fourth of the present invention.
In the fifth of the present invention, the next step is to apply a reactive resin composition consisting of 100 weight parts of a polyol component and A weight parts of a polyisocyanate component and solvent onto the aforementioned olefin-based resin layer, followed by drying, to form a urethane resin layer with a cross-link ratio of 20-93%. This formation process is the same as the process of obtaining the second lamination in the third of the present invention except for the fact that the aforementioned first lamination is used instead of the release film.
Finally, the second release film is laminated onto the urethane resin layer with a cross-link ratio of 20-93% and the urethane resin reaction is completed. Lamination of the second release film can be easily accomplished by stacking the second release film on top of the four layer lamination of the first release film, the pressure-sensitive adhesive layer, the olefin-based resin layer, and the urethane resin laminated one after another, followed by pressing. Stacking and pressing should preferably be done at a temperature near the glass transition temperature of the urethane resin. The method for completing the urethane resin reaction is as described in the third of the present invention.
In the present invention, for the purpose of improving the adhesion between the pressure-sensitive adhesive layer and the urethane resin or the olefin-based resin layer and the adhesion between the urethane resin layer and the olefin-based resin, a treatment to provide surface polarity, such as the corona discharge treatment or the flame treatment, can be performed onthe urethane resin layer and/or the olefin-based resin layer; an anchor coat which is commonly used as the anchor coat for a pressure-sensitive adhesive tape can also be laminated.
For the laminating method to laminate the first lamination and the second lamination, and to laminate the urethane resin layer and the second release film, any lamination method can be used: examples include a method in which the two layers are stacked and then pressed, and a method in which the two layer are stacked and then pressed while being heated with a heating roll.

Pressure-sensitive adhesive tape or sheet and process for producing the same


A method of manufacturing an optical printed circuit board and an optical printed circuit board. The method includes providing a support layer having one or more optical waveguides formed on the support layer, the waveguides having exposed interfaces. A film is provided on one or more of the exposed interfaces, wherein the film has a smoother outer surface than the waveguide interface.

Optical printed circuit board technologies have a wide range of applications which take advantage of their ability to support high bandwidths and other known benefits. For example, it is known to use optical PCBs in aerospace vehicles to convey sensor information to primary processing nodes, or as optical links in large passenger planes to convey sensor and multimedia information across the plane (e.g. video on demand for passengers). They can also be used in automotive applications for the distribution of sensor and media information in cars. They can be used in high performance computing to accommodate huge bandwidth densities around processor nodes, or in a telecommunications setting to accommodate the huge bandwidth densities for embedded optical channels at network nodes. It is also contemplated that optical printed circuit boards may be advantageous in data storage technologies, for example for signal communications in the back planes of disk drive storage enclosures.
Optical printed circuit boards (PCBs) have optical waveguides that are used for the transmission of light signals between components, as well as or instead of conventional copper conductors. Typically, an optical PCB consists of a base or support layer. In areas of the optical PCB where optical waveguides are required, a lower optical cladding layer is provided usually of uniform thickness. On top of this, a layer of optical core material is laid down. The optical core material has a higher refractive index than the cladding layer and will eventually form one or more optical waveguides on the optical PCB.
In a known process used for making optical PCBs, the core layer is laid down in liquid form, e.g. as a curable liquid polymer. A photolithographic mask having a pattern corresponding to the desired shape of the waveguides is arranged over the liquid polymer and the entire resultant structure is then irradiated with electromagnetic radiation of suitable wavelength. Thus, in regions of the mask which are open, the liquid polymer is cured. In other regions, the polymer remains liquid. The mask is removed and the remaining liquid polymer can be washed away with an appropriate solvent known as a "developer" leaving the desired pattern of optical waveguides. Alternatively a dry film optical polymer can be used instead of a liquid polymer.
The remaining core material is typically arranged in patterns of channels which are arranged in some manner so as to be able to couple optical signals between components on the optical PCB when the components are arranged thereon. Last, an upper cladding layer is laid down, so that the channels of core material are completely surrounded by cladding material, and therefore are able to function as optical waveguides. FIG. 1 shows a schematic representation of such a conventional optical PCB and FIG. 2 shows a sectional view of the same optical PCB.
The PCB 2 comprises a base or support layer 4 upon which is arranged a lower cladding layer 6. A plurality of optical waveguides 8 are arranged on the lower cladding layer 6 and have arranged around them an upper cladding layer 10. Thus, the optical waveguides are entirely surrounded by cladding material of the upper cladding layer 10 and the lower cladding layer 6. Typically, the height H of the optical waveguides will be of the order 50 to 70 μm. The width W of each of the optical waveguides is typically of the order 50 to 100 μm. The waveguides can be fabricated to very high accuracy, typically of the order of <1 μm. High accuracy is an important requirement of any optical waveguide structure.
In order to couple optical signals into the waveguides 8, optical components such as transmitters, receivers, 45° mirrors and other optical waveguides, the components must be aligned with respect to the optical waveguide input interfaces or facets 12 with a high alignment tolerance. It is also important to achieve a smooth and normally planar interface at the facets 12 to avoid scattering of light entering or exiting the waveguide 8.
For example, FIG. 3 shows a magnified view of a facet 12 showing a typical roughness profile of a conventionally manufactured optical PCB 2. FIG. 4 shows the effect this roughness produces on light 8 propagating in the waveguide 8 and exiting the facet 12. The roughness of the surface 14 causes scattering of light 24 as the light exits the waveguide 8, causing in turn the attenuation of the optical signal 22. It should be noted that while FIG. 3 shows an output facet 12, the problem of scattering and attenuation of light affects input facets 12 in a similar way. This loss of light is a major problem to be addressed in the manufacture of optical PCBs 2.
Currently, the most effective method of reducing this loss is manual polishing. However, this method is not very effective. Even using this method, the roughness of the facets 12 can cause over 50% of the total optical link loss in the waveguide. Another known technique for reducing attenuation of light due to facet roughness 14 is to use laser ablation of the waveguide facets 12. However, both these methods are unreliable and unrepeatable. In particular, any damage incurred by these methods will be difficult to correct and therefore using these techniques is likely to significantly impact yield in manufacturing optical PCB technology. These methods are also difficult and costly to apply. What is needed is a repeatable, reliable and low cost method of preparing the exposed input and output facets of the waveguide to reduce scattering at the interface.
In instances where non-free space interfaces are used, i.e. where a component couples directly to a waveguide, it is known to apply an index matching oil or gel onto the interface between the waveguide and component to reduce coupling losses. However, this method is unsuitable for an application requiring repeatable engagement and disengagement of the component to the waveguide as the index matching material would flow out during disengagement and attract and hold contaminants (e.g. dust particles), contaminate other components or simply dry up and cease to be effective when next required.

Optical printed circuit board and a method of manufacturing an optical printed circuit board


At least one example embodiment discloses a method of generating an output variable voltage. The method includes obtaining a selected mode of operation, the selected mode of operation being one of an voltage control mode and a frequency mode, determining an input voltage command based on the selected mode of operation, determining an input frequency command based on the selected mode of operation, adjusting at least one of the input frequency command and the input voltage command based on the selected mode of operation, generating a pulse width modulation reference based on the adjusted at least one of the input frequency command and the input voltage command and generating the output variable voltage based on the pulse width modulation reference.

Electric drive devices, such as alternating current (AC) induction motors are used to power systems such as hybrid/electrical vehicles, auxiliary pumps, air compressors, fans, etc. AC induction motors have been widely used for industry applications. A fault-free across-the-line starting capability with Variable Frequency Drives (VFD) may be used with the induction motors. A controller for the drive device controls operation of the drive device. The controller produces control signals which are applied to the terminals of the drive device.
Typically, the controller controls the drive device based on a plurality of information such as a terminal voltage of the drive device and frequency information of the machine.

Methods of generating output variable voltage for electric drive devices and systems thereof


A connecting rod for a piston assembly includes first and second guidance members for guiding a piston assembly within a cylinder during piston stroke along a first axis. The guidance members are supported by first and second support ribs extending from a shaft of the connecting rod and include first and second sliding surfaces for contacting side walls of the cylinder. The connecting rod includes an attachment boss disposed at a first end of the shaft and defines a second axis perpendicular to the first axis. The first and second support ribs extend radially outwardly from the attachment boss and are spaced radially about the second axis by approximately 180 degrees.

1. Field of the Invention
The subject invention relates generally to a piston assembly and a connecting rod for a piston assembly.
2. Description of the Prior Art
Known piston assemblies include a piston head for reciprocation within a cylinder along a piston stroke. A pair of pin bosses depend downwardly from the piston head, with pin bores defined therein. A connecting rod is pivotably attached via a pin to the pin bores, allowing the connecting rod to oscillate as it translates along the piston stroke. As the piston head translates along the piston stroke, and as the connecting rod oscillates, side loads are induced within the assembly. To take these side loads, piston skirts are provided to slide along the side wall of the cylinder. Known piston skirts depend downwardly from the piston head, or extend outwardly from the pin bosses.


This invention concerns a LED light which emits blaze-like radiance comprising a negative prop stand, with one end extending to a negative receiver which can connect to the negative power supply, a positive prop stand with one end extending to a positive receiver which can connect to the positive power supply, a first chip and a second chip established on the negative prop stand, and the first chip is linked to the positive prop stand by a first gold wire, a flicker IC chip established on the positive prop stand, and has the function of continuous linking and breaking of the circuit, the said flicker IC chip is linked to the negative prop stand and the second chip each by a second gold wire and a third gold wire, a plastic sealing cover which covers the interior of the negative prop stand, the positive prop stand, the first chip, the second chip, and the flicker IC chip.

(a) Technical Field of the Invention
The present invention is related to the innovative design in the structure of a LED light, especially LED light that emits blaze-like radiance with flickering and waving visual effects.
(b) Description of the Prior Art
Ever since Edison invented the light bulb, it not only brought light to the world, but also replaced traditional lighting instruments such as candles, oil lamps and torches. It greatly improved the quality of life for people. However, general light bulbs rely mainly on electric current passing through the tungsten filaments to produce light. Therefore, although they are more safe and convenient to use with much lighter effects compared to traditional lighting instruments that they apply to various lighting instruments, they cannot produce the blaze radiance of traditional lighting instruments. Traditional lighting instruments such as candles, oil lamps, and torches produce blaze, which give people flickering and wavering visual effect. The flickering and wavering visual effects not only provide people the feelings of harmony, warmth, variety and passion, but also build the atmosphere of mystery, sacredness, romance and festivity. Consequently, there are still many who apply traditional lighting instruments to some specific occasions and places, such as traditional festivals, temples, churches, restaurants, weddings and funerals. Moreover, the said light bulbs also have defects such as high temperature, power consuming, and short life spans.
Although every country is dedicated on developing a kind of LED (Light Emitting Diode), which would improve the aforementioned light bulb defects such as high temperature, power consuming, and short life span. Furthermore, after all the years of development, innovation and research, the said LED has also been fully applied to various electric appliances, information billboards, communication products and light bulbs, and in turn become so closely related to people's lives to the extent that it is inseparable. However, the LED light generally seen nowadays has functions to simply emit, die out and flicker. Furthermore, when it emits, it has simply a certain brightness of radiance. Therefore, it also cannot produce blaze-like effects like traditional lighting instruments, forming the flickering and wavering radiance which provide people the feelings of harmony, warmth, variety and passion, and build the atmosphere of mystery, sacredness, romance and festivity.
Hence, the inventor has focused on the defect of the preceding prior art LED light not being able to form the flickering and wavering radiance of the blaze. Through deep conception and enthusiastic research in ways to improve the aforementioned defect, this invention has come about over a long period of dedicated refinement and tryout designs.

LED light with blaze-like radiance effect


A hydraulic cam feed unit is provided for moving a tool slide linearly towards and away from a workpiece. The feed unit comprises a hydraulic advance cylinder having a double rod, one end of which is connected to the tool slide to move the tool slide towards and away from the workpiece. A cam engaging member is connected to the opposite end of the double rod for linear movement with the double rod and the tool slide, and a cam is provided in selective engagement with the cam engaging member. A hydraulic feed cylinder has a single rod connected to the cam for linearly reciprocating the cam. When the cam is in engagement with the cam engaging member, the linear movement of the cam controls the linear movement of the tool slide.

1. Field of the Invention
The invention relates generally to a feed unit for a machine tool. More particularly, the invention relates to a cam feed unit for controlling the movement of a machine tool toward and away from a workpiece.
2. Summary of Related Art
Machine tools, such as automatic lathes or automatic plunge type grinders, are usually comprised of a headstock having a rotatable spindle to support a workpiece and a tool carrying slide which is movable toward and away from the workpiece. A feed unit is generally provided for controlling the movement of the tool slide so that the tool slide can be advanced rapidly toward and away from the workpiece both before and after the actual machining operation, while being slowly fed toward the workpiece during the machining operation.
In the past, the feed unit for such machine tools was typically comprised of a single hydraulic cylinder with a servo-type valve having adjustable feeds. Such feed units, however, often provided relatively inconsistent feed of the tool slide and inadequate operator control. In response, many more recently produced automatic machine tools include computer numerically controlled feed units which provide greatly improved consistency, accuracy and ease of control. While such systems have performed well, they are relatively complex and may be prohibitively expensive in some instances.


In an access point apparatus for a wireless LAN system equipped with a terminal location detecting function, memory capacity required for the access point apparatus is reduced. A received signal memory control module controls access such that a memory space of a received signal memory can be reused by performing sequentially overwrite operation while stopping capturing of the received signal in response to a packet detection signal outputted from a packet detecting module.

1. Field of the Invention
The present invention generally relates to a wireless LAN (Local Area Network) system. More particularly, the present invention is concerned with an access point apparatus for measuring or determining the current location or position of a mobile terminal in the wireless LAN system by making use of a radio signal. Incidentally, the access point apparatus may also be referred to as the access point station or base station in more general terms.
2. Description of the Related Art
For better understanding of the concept underlying the present invention, description will firstly be made of background techniques of the invention. As a method of measuring or determining the current location of a terminal with the aid of a radio signal used in the wireless LAN system, there can be mentioned a method which is disclosed in A. Ogino et al's article "INTEGRATED WIRELESS LAN ACCESS SYSTEM, (1) STUDY ON LOCATION SYSTEM" in "The Collection of Lecture Drafts in the General Convention of The Institute of Electronics, Information and Communication Engineers in Japan (2003)", B-5-203, p.662. In the following, description will be made of the configuration and operation of the wireless LAN access point apparatus (base station) disclosed in the Ogino et al reference.
FIG. 9 of the accompanying drawings is a schematic diagram which shows, by way of example, a configuration of a wireless LAN system equipped with a terminal locating facility (i.e., function for determining a location or position of a terminal). A plurality of access point apparatuses or base stations (e.g. three access point apparatuses 1, 2 and 3 in the case of the LAN system illustrated in FIG. 9) are connected to a server 6 by way of a network 5 constituted by a public network and a mobile communication network. The terminal denoted by reference numeral 4 performs transaction of information or data with the server 6 through the medium of these access point apparatuses or base stations.
A processing flow for determining the location of the terminal 4 in the LAN system shown in FIG. 9 will be described below. The terminal 4 transmits or sends a radio signal. The access point apparatuses or base stations 1, 2 and 3 receive the radio signal to execute the signal processing which is required for determining the location of the terminal. In addition, each of the access point apparatuses 1 to 3 informs the server 6 of the result of the above-mentioned signal processing as executed via the network 5. On the basis of the signal processing result received from the individual access point apparatuses or stations, the server 6 arithmetically determines the location of the terminal 4.
FIG. 10 of the accompanying drawings is a block diagram showing generally a structure of a hitherto known or conventional access point apparatus for realizing the processing flow mentioned above. Referring to the figure, a signal receiving unit 101 is designed to perform a reception processing at a high/intermediate frequency corresponding to the radio signal received via an antenna 100, a demodulation processing of a base-band signal and an AD conversion (Analog to Digital conversion) to thereby generate a received signal.
On the other hand, a received signal memory control module 106 is so designed or programmed as to perform an access control for storing the received signal generated by the signal receiving unit 101 in a received signal memory 102 in response to a capture start command messaged from a terminal location determining signal processing module 103 via a signal line 104. In that case, the received signal memory control module 106 holds as a capture start timing the timing which is indicated by a clock 107 when storage of the received signal in the received signal memory 102 is started. In this conjunction, the clock 107 may be constituted, for example, by a counter which operates under the timing of a clock signal used in the access point apparatus.
Next, referring to FIGS. 11 and 12 of the accompanying drawings, description will turn to an access control method carried out by the received signal memory control module 106 in the conventional access point apparatus or station. It is assumed that the storage of the received signal is started at a timing Tp0 shown in FIG. 11. In that case, the received signal memory control module 106 firstly stores the timing Tp0 as the capture start timing. In addition, the received signal memory control module 106 stores the received signal at the timing Tp0 in the received signal memory 102 at an address Ap0, as shown in FIG. 12. In this conjunction, the address Ap0 may be a predetermined address or alternatively it may be designated by the terminal location determining signal processing module 103 upon issuance of the capture start command from the terminal location determining signal processing module 103. In succession, the received signal memory control module 106 carries out the access control such that the received signal is stored sequentially in the received signal memory 102 at the addresses Ap0+1, Ap0+2, . . . in this order, as is illustrated in FIG. 12. When the received signal has been stored up to the address Ap1 in the received signal memory 102, the received signal memory control module 106 terminates or ends the process of storing the received signal in the received signal memory 102. Incidentally, the address Ap1 may be a predetermined address or alternatively it may be designated by the terminal location determining signal processing module 103 when the received signal capture start command is issued by the terminal location determining signal processing module 103.
Upon completion of the storage of the received signal in the received signal memory 102, the received signal memory control module 106 sends a received signal capture end message and the capture start timing to the terminal location determining signal processing module 103 via a signal line 105.
Upon reception of the capture end message mentioned above, the terminal location determining signal processing module 103 executes the signal processing required for arithmetically determining the location of the mobile terminal on the basis of the received signal stored in the received signal memory and the capture start timing mentioned above, the result of the signal processing being then messaged or transferred to the server 6 shown in FIG. 9. As the signal processing required for the arithmetic determination of the location or position of the mobile terminal, there can be mentioned a processing for arithmetically determining the reception timing of the signal sent from the terminal, a processing for arithmetically determining a delay profile for the determination of the reception timing, etc. In this conjunction, it should be added that a matched filter, for example, may be employed for the arithmetic determination of the delay profile. Further, for arithmetically deriving the reception timing of the received signal from the delay profile as obtained, a method disclosed in e.g. JP-A-2002-14152 may be adopted. Alternatively, the received signal stored in the received signal memory 102 may be intactly transferred to the server 6 without executing any particular processing on the received signal stored in the received signal memory 102.
The server 6 then arithmetically determines the location or position of the terminal on the basis of the results of the signal processings sent from the individual access point apparatuses (base stations) 1, 2 and 3 by resorting to, for example, a trilateration method described, for example, in the Ogino et al reference cited hereinbefore.

Access point apparatus for a system for determining the location of a terminal and a terminal location determining method


A high fT and fmax bipolar transistor includes an emitter, a base, and a collector. The emitter has a lower portion and an upper portion that extends beyond the lower portion. The base includes an intrinsic base and an extrinsic base. The intrinsic base is located between the lower portion of the emitter and the collector. The extrinsic base extends from the lower portion of the emitter beyond the upper portion of the emitter and includes a continuous conductor that extends from underneath the upper portion of the emitter and out from underneath the upper portion of the emitter. The continuous conductor provides a low electrical resistance path from a base contact (not shown) to the intrinsic base. The transistor may include a second conductor that does not extend underneath the upper portion of the emitter, but which further reduces the electrical resistance through the extrinsic base.

With each generation of microelectronic semiconductor devices, e.g., microprocessors, memories, application specific integrated circuits, and other devices, the speed at which these devices operate increases incrementally. In the same technology node, SiGe heterojunction bipolar transistor (HBT) devices have higher speeds than the field effect transistors (FET) in a CMOS technology. Due to this higher speed performance of SiGe HBTs and other related reasons, bipolar complimentary metallic oxide semiconductor (BiCMOS) fabrication is finding more use in a variety of application in semiconductor devices.
A conventional BiCMOS bipolar transistor 20 is shown in FIG. 1. Transistor 20 shown is an n-p-n transistor having an n-type emitter 24, a p-type base 28, and an n-type collector generally represented by doped collector pedestal 32 formed in a wafer 36. In addition to collector pedestal 32, wafer 36 includes a first deep trench insulator 40 and a second shallow trench isolator (STI) 44 for isolating transistor 20 from surrounding microelectronic components (not shown), e.g., other transistors, capacitors, or the like. A heavily-doped sub-collector 48 underneath the collector pedestal and the STI 44 provides a low-resistance link to collector contact (not shown). Emitter 24 often generally has a T-shaped vertical cross section so as to provide a relatively small lower portion 52 proximate collector pedestal 32 (to achieve a small cross-sectional area to limit the current flow to the collector) while providing a relatively large upper portion 56 to interface with an emitter contact 58.
Base 28 typically comprises an intrinsic base 60 that includes a thin, generally highly p-doped layer (not shown) located between emitter and collector and an extrinsic base 64 that provides an electrical pathway between a base contact (not shown) and the intrinsic base. During the process of fabricating transistor 20, extrinsic base 64 is typically made by depositing a polysilicon layer 68 atop wafer 36. Subsequently, polysilicon layer 68 is etched to provide a trench 72 for lower portion 52 of emitter 24, and then the emitter is formed. After emitter 24 is formed, polysilicon layer 68 is silicidated with a metal to form a conductor 76 so as to increase the conductance of extrinsic base 64. However, because emitter 24 has already been formed, the portion 80 of extrinsic base 64 beneath emitter 24 is not silicidated due to the presence of the emitter above that blocks metal atom from reaching this portion of the extrinsic base.
The fact that portion 80 of extrinsic base 64 remains unsilicidated is significant because the resistance Rpoly of the polysilicon in this portion is much higher than the resistance Rsilicide of its silicidated counterpart located out from underneath emitter 24. For example, Rpoly may be about 100-200 Ω/sq for a 1000 Å thickness, whereas Rsilicide for one-third of the thickness may be about 8 Ω/sq. Because Rpoly is relatively high, the resistance to current flowing through extrinsic base 64 is relatively high.
As device feature size scales down with advancement in technology, high-speed SiGe HBTs have thinner base to reduce the transit time of electrons to go from emitter to collector, thus increase the unity current gain frequency fT. A thinner base, however, increases the base resistance, limiting maximum achievable oscillation frequency fmax, which is also necessary for high speed application of the devices. Thus it is important to innovate ways to reduce base resistance Rb

International Business Machines Corporation


A method and apparatus for scheduling the processing of commands by a plurality of cryptographic algorithm cores in a network processor.

As is known in the art, a network processor is a programmable hardware device designed to process packets in a packet switching network at high speed. Network processors typically differ from other processors in that network processors include hardware that can rapidly perform protocol processing tasks.
As is also known, there is a trend to provide network processors which perform cryptographic processing of packet data. To facilitate the cryptographic processing, the network processors include cryptographic acceleration units (also referred to as "crypto units"). The crypto units accelerate the cryptographic processing of packet data to support cryptographic processing at line rate. One example of a network processor including a crypto unit is the Intel® IXP2850 network processor manufactured by Intel Corporation, 2200 Mission College Blvd. Santa Clara, Calif. 95052 USA.
Two types of cryptographic processing that are commonly performed on packet data are authentication processing (or more simply authentication) and ciphering processing (or more simply ciphering). Authentication is the process of creating a digest of the packet, which is sent along with the packet, and allows the receiver to verify that the packet was indeed sent by the sender (rather than by some third party) and was not modified in transit. Ciphering is the process of encrypting the packet, so that only the intended receiver, with the correct cryptographic key, can decrypt the packet and read its contents. The most commonly used security protocols perform both ciphering and authentication on each packet.
In order to support the ciphering of relatively small packets, the crypto units in the Intel® IXP2850 each have six processing contexts, which are each used to process one packet at a time. Each processing context contains storage for the cipher keys and algorithm context associated with the processing of one packet. Multiple processing contexts allow the latency of loading cryptographic key material and packet data to be hidden by pipelining the loading of data and key material into some of the contexts with the processing of data in other contexts. This allows the crypto unit to achieve close to full utilization of the cipher and authentication cores.
The crypto units in the Intel® IXP2850 implement the 3DES and AES cipher algorithms as well as the SHA1 authentication algorithm. Each of the crypto units contains a single AES core and a pair of 3DES and SHA1 cores because the structure of those algorithms make it difficult for a single core to operate at the required data rates. By implementing a pair of cores and allowing both cores to process data in parallel, the crypto units meet desired data rate requirements. This approach, however, presents a problem of how to schedule the operation of the individual cores within a pair.
There are several ways to solve this problem. For example, the contexts within a crypto unit can be divided into two groups and the each of the cores in a pair can be assigned to process requests from a group of contexts. Since the programmer controls which packets are processed by which processing context, this approach pushes the problem of load balancing work between the individual cores in a pair to the programmer.
For example, in a 3DES crypto unit the programmer must ensure that half of the packets requiring processing by the 3DES algorithm are assigned to one of the contexts serviced by one 3DES core, and the other half of the packets requiring processing by the 3DES algorithm are assigned to one of the contexts serviced by the other 3DES core.

This patent is subject to a terminal disclaimer.

Method and apparatus for scheduling the processing of commands for execution by cryptographic algorithm cores in a programmable network processor


The internal supply voltage generating circuit includes a level trimming circuit for regulating a first reference voltage and generating a predetermined second reference voltage, and an internal reference voltage generating circuit connected to the level trimming circuit, for generating internal reference voltages using the predetermined second reference voltage. The internal supply voltage generating circuit prevents the circuit area from increasing, reduces a variation in a load when regulating a feedback voltage, and generates a plurality of highly accurate internal supply voltages.

The present invention relates to an internal supply voltage generating circuit and a method of generating an internal supply voltage. More particularly, it relates to an internal supply voltage generating circuit in a semiconductor memory device and an internal supply voltage generating method, which generate an internal supply voltage by dropping an external supply voltage and provide the individual circuits of the semiconductor memory device with the generated internal supply voltage.
Due to the micronization of the wiring pattern and the reduction in power consumption, a semiconductor memory device is provided with an internal supply voltage generating circuit which drops an external supply voltage to generate an internal supply voltage to be supplied to the individual internal circuits. The internal supply voltage generating circuit includes a reference voltage generating circuit and a voltage-drop regulator.
The reference voltage generating circuit generates a desired reference voltage from the external supply voltage and supplies the reference voltage to the voltage-drop regulator. The voltage-drop regulator receives the reference voltage and the external supply voltage and generates a stable internal supply voltage by dropping the external supply voltage in accordance with the reference voltage. The voltage-drop regulator supplies the internal supply voltage to various internal circuits via internal power lines.
It is desirable that a variation in the internal supply voltage be as small as possible. Therefore, the reference voltage, which is supplied to the voltage-drop regulator, should preferably have a high precision. However, there is a current of several micro amperes flowing in the reference voltage generating circuit and the threshold values of the individual transistors of the reference voltage generating circuit are not constant due to a productional variation. This results in a variation in reference voltage.
As a solution to reduce the variation in reference voltage, an internal supply voltage generating circuit having an internal reference generating circuit connected between a reference voltage generating circuit and a voltage-drop regulator has been proposed. The internal reference generating circuit regulates the reference voltage to a desired voltage and supplies the regulated reference voltage to the voltage-drop regulator.
FIG. 1 is a schematic block diagram of a conventional internal supply voltage generating circuit 50. The internal supply voltage generating circuit 50 includes a reference voltage generating circuit 51, an internal reference generating circuit 52 and a voltage-drop regulator 53.
The reference voltage generating circuit 51 generates a desired first reference voltage Vflat1 from an external supply voltage Vcc and supplies the first reference voltage Vflat1 to the internal reference generating circuit 52. The internal reference generating circuit 52 generates a second reference voltage Vflat2 using the first reference voltage Vflat1.
As shown in FIG. 2, the internal reference generating circuit 52 includes a differential amplifier 56, a driver 57, a trimming circuit 58 and a phase compensation circuit 59.
The differential amplifier 56 includes a differential amplification section which comprises a first N channel MOS (NMOS) transistor Q1 and a second NMOS transistor Q2, as shown in FIG. 3. The sources of the NMOS transistors Q1 and Q2 are grounded via a current-controlling NMOS transistor Q3. The gate of the NMOS transistor Q3 is connected to the gate of the first NMOS transistor Q1.
The drains of the NMOS transistors Q1 and Q2 are connected to an external supply voltage Vcc via P channel MOS (PMOS) transistors Q4 and Q5 respectively. The gates of the PMOS transistors Q4 and Q5 are connected together to the drain of the second NMOS transistor Q2.
The first reference voltage Vflat1 from the reference voltage generating circuit 51 is supplied to the gate of the first NMOS transistor Q1. A feedback voltage Vf from the trimming circuit 58 is supplied to the gate of the second NMOS transistor Q2. The drain of the first NMOS transistor Q1 also serves as the output terminal of the differential amplifier 56, which is connected to the driver 57.
The driver 57 includes a PMOS transistor Q6 whose gate is supplied with an output voltage Vout of the differential amplifier 56. The source of the PMOS transistor Q6 is connected to the external supply voltage Vcc and the drain of the PMOS transistor Q6 is connected to the voltage-drop regulator 53. The second reference voltage Vflat2 is supplied to the voltage-drop regulator 53 (in FIG. 1) from the drain of the PMOS transistor Q6. The drain of the PMOS transistor Q6 is grounded via the trimming circuit 58.
The trimming circuit 58 includes a voltage dividing circuit, which includes four resistors R1 to R4, and a selection circuit. The selection circuit includes three transfer gates G1 to G3, each connected between the individual nodes between one of the resistors R1-R4 of the voltage dividing circuit and the gate of the second NMOS transistor Q2 of the differential amplifier 56. One of the three transfer gates G1-G3 is turned on by selection signals xcfx861 to xcfx863 and the remaining two transfer gates are turned off.
The divided voltage, which is produced by the voltage dividing circuit, is supplied via the turned-on transfer gate to the non-inverting input terminal (the gate of the second NMOS transistor Q2) of the differential amplifier 56 as the feedback voltage Vf.
The drain of the PMOS transistor Q6 is grounded via the phase compensation circuit 59. The phase compensation circuit 59 includes a resistor R5 and a capacitor Cl.
The differential amplifier 56 regulates the second reference voltage Vflat2 by raising or lowering the output voltage, such that the feedback voltage Vf substantially coincides with the first reference voltage Vflat1. That is, the differential amplifier 56 detects whether the second reference voltage Vflat2 is a predetermined voltage during a test conducted before shipment. When the second reference voltage Vflat2 is not the predetermined voltage, one of the three transfer gates G1-G3 is turned on to regulate the feedback voltage Vf, so that the second reference voltage Vflat2 is adjusted to the predetermined voltage. Therefore, (the voltage-drop regulator 53 produces a highly accurate and stable internal supply voltage Vdd in accordance with the second reference voltage Vflat2 whose productional variation has been compensated.
The phase compensation circuit 59 prevents the internal reference generating circuit 52 from performing an oscillating operation due to the phase shift of the feedback voltage Vf supplied to the differential amplifier 56.
A semiconductor memory device has a plurality of internal supply voltage generating circuits according to the usage of the internal supply voltage Vdd (e.g., the supply voltage for peripheral function circuits, the supply voltage for memory core circuits). Specifically, because of various factors such as the problems related to the withstand voltage and power consumption, which originat from the micro-fabrication process, power supply noise and the set level of the voltage-drop potential, a semiconductor memory device has an internal supply voltage generating circuit for input/output circuits, an internal supply voltage generating circuit for peripheral function circuits and an internal supply voltage generating circuit for a memory array, which are independently provided.
As shown in FIG. 4, a plurality of internal reference generating circuits 64, 65 and 66 are connected to one reference voltage generating circuit 51, and a plurality of voltage-drop regulators 61, 62 and 63 are respectively connected to the internal reference generating circuits 64, 65 and 66. The internal reference generating circuits 64, 65 and 66 respectively generate second reference voltages Vflat2a, Vflat2b and Vflat2c using a first reference voltage Vflat1. The voltage-drop regulators 61, 62 and 63 respectively generate internal supply voltages Vdda, Vddb and Vddc from the second reference voltages Vflat2a, Vflat2b and Vflat2c.
In this case, however, the provision of the plurality of internal reference generating circuits 64, 65 and 66 increases the circuit area.
As a solution to this shortcoming, as shown in FIG. 5, a single internal reference generating circuit 67, which generates a plurality of second reference voltages Vflat2a, Vflat2b and Vflat2c, has been proposed. Specifically, the second reference voltage Vflat2a is an output from the drain of the PMOS transistor Q6 of the driver 57. The second reference voltages Vflat2b and Vflat2c are outputs from arbitrary nodes between resistors R11 to R15 of the voltage dividing circuit of the trimming circuit 58.
In the trimming circuit 58, one of the three transfer gates G1-G3 is selected based on a variation in the first reference voltage Vflat1. Therefore, the loads of the voltage-drop regulators 62 and 63 are applied to the non-inverting input terminal of the differential amplifier 56 via the selected transfer gate. This significantly changes the load on the non-inverting input terminal of the differential amplifier 56. The phase compensation circuit 59 cannot compensate for a variation in the load, causing the internal reference generating circuit 67 to oscillate.
To make variations in the internal supply voltages Vdd, Vdda, Vddb and Vddc as small as possible, it is desirable to increase the number of resistors in the voltage dividing circuit of the trimming circuit 58. As shown in FIG. 6, a trimming circuit 70 includes a voltage dividing circuit having seventeen resistors Ra1 to Ra17 and a selection circuit having sixteen transfer gates Ga1 to Ga16. By selecting one of the transfer gates Ga1-Ga16, there are sixteen possible ways of selecting the feedback voltage Vf. This allows a variation in the first reference voltage Vflat1 to be adjusted more precisely, thus reducing variations in the internal supply voltages Vdd, Vdda, Vddb and Vddc. However, the overall circuit area is increased by the increases in the number of resistors in the voltage dividing circuit, the number of transfer gates in the selection circuit and the number of signal lines for the sixteen transfer gates Ga1-Ga16.
Accordingly, it is an object of the present invention to provide an internal supply voltage generating circuit that prevents the circuit area from increasing, reduces a variation in a load when regulating a feedback voltage, and generates a plurality of highly accurate internal supply voltages.
In one aspect of the present invention, an embodiment of an internal supply voltage generating circuit is provided. The internal supply voltage generating circuit includes a level trimming circuit for regulating a first reference voltage and generating a predetermined second reference voltage, and an internal reference voltage generating circuit. The latter is connected to the level trimming circuit, for generating one or more internal reference voltages using the predetermined second reference voltage.
In another aspect of the present invention, another embodiment of an internal supply voltage generating circuit is provided. The internal supply voltage generating circuit includes a level trimming circuit for regulating a first reference voltage and generating a predetermined second reference voltage. The level trimming circuit includes a voltage dividing circuit for dividing the second reference voltage and generating a plurality of divided voltages. The level trimming circuit regulates the first reference voltage using at least one divided voltage selected from the plurality of divided voltages as a feedback voltage. An internal reference voltage generating circuit is connected to the level trimming circuit to generate one or more internal supply voltages using the predetermined second reference voltage. A phase compensation circuit is connected between the level trimming circuit and the internal reference voltage generating circuit to compensate for a phase shift of the feedback voltage.
In yet another aspect of the present invention, a method for generating an internal supply voltage is provided. First, a first reference voltage is generated from an external supply voltage, and a predetermined second reference voltage is generated by regulating the first reference voltage. Compensating for a phase shift of the predetermined second reference voltage is performed to generate a compensated predetermined second reference voltage. A plurality of internal reference voltages are generated using the compensated predetermined second reference voltage. Then, a plurality of internal supply voltages are generated using the plurality of internal reference voltages.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

Internal supply voltage generating circuit and method of generating internal supply voltage using an internal reference voltage generating circuit and voltage-drop regulator