Substrate Is Glass Patents (Class 216/97)
  • Patent number: 5846444
    Abstract: A method and apparatus for treating a surface on a glass article with a fluid. The article is surrounded by a containment system for the treating fluid and the fluid is continuously agitated by an agitator.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: December 8, 1998
    Assignee: Corning Incorporated
    Inventors: Stephen P. Edwards, Donald B. Kloeber, Joseph W. Neubert, Stephen R. Ormsby
  • Patent number: 5846628
    Abstract: Disclosed herein is a substrate for a magnetic disc comprising a glass substrate having fine protrusions on its surface, the protrusions having a height of 50 to 1000 .ANG., a width of 0.01 to 1 .mu.m, a density of 10 to 1000 per 100 .mu.m.sup.2 and an area ratio of 0.1 to 50%, and a ratio of peak height on a mean line (R.sub.p) to maximum height (R.sub.max) with respect to surface roughness of the substrate being at least 60%. Further, a process for preparing the substrate and a magnetic disc having the substrate are disclosed.Because the substrate according to the present invention has appropriate protrusions on its surface, a friction force and an adsorbing force between a head and a magnetic disc can be reduced, leading to the improvement of the CSS and the anti-head stick properties. In addition, the S/N ratio is not affected because the fine concave portions formed on the surface of the substrate are shallow.
    Type: Grant
    Filed: April 2, 1996
    Date of Patent: December 8, 1998
    Assignee: Mitsubishi Kasei Corporation
    Inventors: Toru Kuroe, Fumiaki Yokoyama, Daisuke Mouri
  • Patent number: 5843321
    Abstract: Methods of manufacturing optical elements such as diffraction type lenses, aspherical lenses and diffraction gratings are disclosed. Deposited on a glass substrate is a workpiece film made of a material which can be machined much more easily than the substrate. Then the workpiece film is machined to form a predetermined shape or contour therein. After forming the predetermined shape or contour in the workpiece film, the workpiece film and substrate are subjected to etching to duplicate the predetermined shape or contour formed in the workpiece film into the substrate.
    Type: Grant
    Filed: April 19, 1994
    Date of Patent: December 1, 1998
    Assignee: Olympus Optical Company, Ltd.
    Inventors: Yasuhiro Kamihara, Hitoshi Ohashi, Ayami Imamura
  • Patent number: 5837113
    Abstract: A small glass electrode and process for preparation thereof, the small glass electrode having a bonded structure and comprising a reference electrode composed of silver/silver chloride, a glass substrate having a pad embedded therein, the pad being composed of gold or platinum and circuit-connected to the reference electrode, and a silicon substrate having a (100) plane selectively etched by the anisotropic etching technique and comprising a groove for injecting an electrolyte composed of an aqueous solution containing chlorine such as KCA, or HCA, at least one hole for holding the electrolyte and a glass film formed in a portion corresponding to the reference electrode. The structure of the small glass electrode may be produced by the disclosed process easily and at low cost. Additionally, the small glass electrode, in differing embodiments, may include a reference electrode and a temperature sensor.
    Type: Grant
    Filed: February 8, 1996
    Date of Patent: November 17, 1998
    Assignee: Fujitsu Limited
    Inventors: Hiroaki Suzuki, Akio Sugama, Naomi Kojima
  • Patent number: 5833869
    Abstract: A method (202) for etching photolithographically produced quartz crystal blanks for singulation. In a first step (202), a quartz wafer is plated on both sides with metal and subsequently coated on both sides with photoresist. In a second step (204), the photoresist is patterned and developed and the metal layer on one side is etched through to form a narrow channel in the quartz defining a perimeter of a quartz blank. In a third step (206), the quartz channel is preferentially etched partially into the wafer along parallel atomic planes to provide a mechanically weak junction between the quartz wafer and the blanks to be singulated. In a fourth step (208), the photoresist layers are stripped from the quartz wafer. In a final step (210), the quartz blank is cleaved substantially along the bottom of the quartz channel to singulate the crystal blanks from the quartz wafer.
    Type: Grant
    Filed: January 16, 1997
    Date of Patent: November 10, 1998
    Assignee: Motorola Inc.
    Inventors: Kevin Haas, Robert Witte, Sang Kim
  • Patent number: 5833871
    Abstract: In a method of finishing a surface of a floating type magnetic head in which a sliding contact surface opposing a magnetic recording medium is made of a polycrystal material comprising at least two kinds of phases of different compositions mixed together, the sliding contact surface is roughened by treatment with an etching solution in accordance with a chemical etching process. The sliding contact surface of the floating type magnetic head can be mirror-finished with an appropriate surface roughness, so that satisfactory CSS performance and good electromagnetic performance can be obtained. The sliding contact surface is preferably made of a polycrystal ceramic material selected from the CaTiO.sub.3 ceramic system, the AlTiC ceramic system and the MnO-NiO ceramic system. The etching solution contains aqueous hydrogen peroxide as an oxidizing agent and is preferably an aqueous hydrogen peroxide and ammonia solution.
    Type: Grant
    Filed: July 7, 1997
    Date of Patent: November 10, 1998
    Assignee: Minebea Co., Ltd.
    Inventors: Takeshi Matsushita, Shinya Ibaraki, Shigeyuki Adachi
  • Patent number: 5788871
    Abstract: A wet-etching method which determines a desired etch-ended point includes the steps of providing an etchant solution in a bath, performing the wet-etch process by dipping a material to be etched in the bath, measuring a weight variation value of the material during the wet etch process, calculating a thickness variation value of the material by using the weight variation value, and stopping the wet-etch process when the thickness variation value reaches a preset value.
    Type: Grant
    Filed: April 16, 1996
    Date of Patent: August 4, 1998
    Assignee: LG Semicon Co., Ltd.
    Inventor: Yun Jun Huh
  • Patent number: 5785874
    Abstract: An optical waveguide device including a support substrate, a glass substrate, and a thin film layer formed on at least one of the substrates, if required. The support substrate and the glass substrate are bonded through direct bonding, and the glass substrate includes an optical waveguide as a part thereof. A layer having a refractive index lower than that of the glass substrate may be formed on the glass substrate. A method for fabricating such an optical waveguide device is also provided.
    Type: Grant
    Filed: August 4, 1995
    Date of Patent: July 28, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Kazuo Eda
  • Patent number: 5783097
    Abstract: A simple, non critical, low cost process step is added to the manufacture of integrated circuit wafers to remove a ridge of dielectric material remaining at the flat edge of the wafer after an edge rinse has removed the ridge of dielectric from the circular edges of the wafer. A layer of dielectric, such as Spin-On-Glass or the like, is formed on the wafer. An edge rinse is then used to remove the ridge of dielectric formed at the wafer edge, however the edge rinse does not remove the ridge of dielectric at the flat edge of the wafer. A layer of photoresist is formed on the wafer, selectively exposed, and developed to form a photoresist mask. The flat edge of the wafer is then dipped in buffered oxide etch to remove the dielectric material at the flat edge of the wafer. The photoresist mask is then stripped and processing of the wafer is continued.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: July 21, 1998
    Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.
    Inventors: Chi-Shen Lo, Chao-Hsin Chang, Chia-Hsiang Chen, Hsien-Wen Chang, Chih-Heng Shen
  • Patent number: 5779928
    Abstract: A film dissolving liquid is ejected from a needle-shaped nozzle onto a peripheral edge portion of a substrate surface of a SOG film, while being subjected to the film dissolving liquid. The substrate is rotated in order to dissolve and remove the SOG film from the peripheral edge portion of the substrate. The film dissolving liquid is a solvent or mixture of two or more solvents selected from the group cyclohexanone, .gamma.-butyrolactone, ethyl lactate or ethyl pyruvate. As a result, a swelling of the SOG film is not created at the edge portion of the substrate. A crack is not therefore created at the edge portion of the SOG film, and generation of particles due to a damage at the film swelling portion thereof is prevented.
    Type: Grant
    Filed: February 12, 1997
    Date of Patent: July 14, 1998
    Assignee: Dainippon Screen Mfg. Co. Ltd.
    Inventors: Tetsuro Yamashita, Tsuyoshi Mitsuhashi, Manabu Yabe
  • Patent number: 5738800
    Abstract: A composition is provided for polishing a composite comprised of silica and silicon nitride comprising: an aqueous medium, abrasive particles, a surfactant, and a compound which complexes with the silica and silicon nitride wherein the complexing agent has has two or more functional groups each having a dissociable proton, the functional groups being the same or different.
    Type: Grant
    Filed: February 19, 1997
    Date of Patent: April 14, 1998
    Assignee: Rodel, Inc.
    Inventors: Sharath D. Hosali, Anantha R. Sethuraman, Jiun-Fang Wang, Lee Melbourne Cook
  • Patent number: 5736061
    Abstract: A semiconductor sensor mount is formed as follows: through holes are formed that penetrate a glass plate; and then the glass plate having the through holes is dipped into hydrofluoric acid etchant to smooth the inner peripheral surfaces of the respective through holes. By etching the inner peripheral surfaces of the respective through holes after the through hole formation, minute roughness and cracks formed on the inner peripheral surfaces are removed, and thereby the areas for adsorbing gas are substantially reduced. That is, vacuums within the through holes can be maintained at a high degree during the anodic bonding, whereby undesirable electric discharge phenomena are prevented even if a relatively high voltage is applied during the anodic bonding. Accordingly, the yield of products can be improved while improving productivity.
    Type: Grant
    Filed: June 27, 1996
    Date of Patent: April 7, 1998
    Assignees: Nippondenso Co. Ltd., Iwaki Glass Co., Ltd.
    Inventors: Tsuyoshi Fukada, Yasutoshi Suzuki, Koushu Satoh, Hiroaki Kawashima
  • Patent number: 5709803
    Abstract: This invention involves a fiber probe device and a method of making it. The probe includes a relatively thick upper cylindrical portion, typically in the form of a solid right circular cylinder, terminating in a tapered portion that terminates in a relatively thin lower cylindrical portion, typically also in the form of a solid right circular cylinder, the lower portion having a width (diameter) in the approximate range of as little as approximately 0.05 .mu.m.
    Type: Grant
    Filed: February 17, 1995
    Date of Patent: January 20, 1998
    Assignee: Lucent Technologies Inc.
    Inventors: Robert William Filas, Herschel Maclyn Marchman
  • Patent number: 5695661
    Abstract: The present invention is directed to a novel etching process for a semiconductor material which inhibits corrosion of metal comprised of pretreating the material, preferably with a surfactant, and then exposing the material to a mixture comprising salt, a buffered oxide etch, and optionally a surfactant.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 9, 1997
    Assignee: Micron Display Technology, Inc.
    Inventors: Robert T. Rasmussen, Surjit S. Chadha, David A. Cathey
  • Patent number: 5681484
    Abstract: A system for processing a plurality of tests or syntheses in parallel comprising a sample channel for moving samples into a microlaboratory array of a plurality of wells connected by one or more channels for the testing-or synthesis of samples, a station for housing the array and an optical system comprising at least one light source and at least one light detector for measuring the samples in the array, and a means of electrically connecting said array to an apparatus capable of monitoring and controlling the flow of fluids into the array. Samples are loaded from a common loading channel into the array, processed in the wells and measurements taken by the optical system. The array can process many samples, or synthesize many compounds in parallel, reducing the time required for such processes. Etching from both sides of a substrate using patterned photoresist and metal layers to form a network of capillary channels for separately transporting a plurality of different liquids.
    Type: Grant
    Filed: May 31, 1995
    Date of Patent: October 28, 1997
    Assignee: David Sarnoff Research Center, Inc.
    Inventors: Peter John Zanzucchi, Satyam Choudary Cherukuri, Sterling Edward McBride
  • Patent number: 5676852
    Abstract: This invention involves a fiber probe device and a method of making it. The probe includes a relatively thick upper cylindrical portion, typically in the form of a solid right circular cylinder, terminating in a tapered portion that terminates in a relatively thin lower cylindrical portion, typically also in the form of a solid right circular cylinder, the lower portion having a width (diameter) in the approximate range of as little as approximately 0.05 .mu.m.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: October 14, 1997
    Assignee: Lucent Technologies Inc.
    Inventors: Robert William Filas, Herschel Maclyn Marchman
  • Patent number: 5660741
    Abstract: A small glass electrode and process for preparation thereof are disclosed. This small glass electrode is characterized in that said glass electrode, which has a bonded structure comprises a reference electrode composed of silver/silver chloride, a glass substrate having a pad embedded therein, said pad being composed of gold or platinum and circuit-connected to the reference electrode, and a silicon substrate having a (100) plane selectively etched by the anisotropic etching technique and comprising a groove for injecting an electrolyte composed of an aqueous solution containing chlorine such as KCl, or HCl, at least one hole for holding the electrolyte and a glass film formed in a portion corresponding to the reference electrode. By this structure, the small glass electrode can be easily manufactured at a low cost.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: August 26, 1997
    Assignee: Fujitsu Ltd.
    Inventors: Hiroaki Suzuki, Akio Sugama, Naomi Kojima
  • Patent number: 5656056
    Abstract: Fluoride glass optical fibers are fabricated by minimizing the number of high-temperature operations. A tube comprising an external layer of a first fluoride glass of composition suitable to form the cladding of the fiber and an internal layer of a second fluoride glass of composition suitable to form the core of the fiber is prepared by a conventional rotational casting technique. Then, the internal layer is thinned by means of chemical etching at ambient temperature until the attainment of a ratio between the volumes of the two layers that corresponds to the ratio between the core and cladding diameters required for a single mode fiber, and the resulting tube is drawn.
    Type: Grant
    Filed: December 22, 1994
    Date of Patent: August 12, 1997
    Assignee: Cselt-Centro Studi E Laboratori Telecomunicazioni S.P.A.
    Inventors: Marco Braglia, Giuseppe Cocito
  • Patent number: 5650075
    Abstract: A method for etching (200) photolithographically produced quartz crystal blanks for singulation. First, a quartz wafer is plated on both sides with metal and subsequently coated on both sides with photoresist (202). Second, the photoresist is patterned and developed and the metal layers etched to define the periphery of a quartz blank with a narrow quartz channel exposed between the blank to be singulated and the parent quartz wafer (204). Third, the quartz channel is preferentially etched partially into the wafer along parallel atomic planes to provide a mechanically weak junction between the quartz wafer and the blank to be singulated, while the periphery around the remainder of the quartz blank is etched completely through the parent quartz wafer (206). Fourth, the photoresist layers are stripped from the quartz wafer (208). Finally, the quartz blank is cleaved substantially along the bottom of the quartz channel to singulate the crystal blank from the wafer (210).
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: July 22, 1997
    Assignee: Motorola, Inc.
    Inventors: Kevin L. Haas, Robert S. Witte, Charles L. Zimnicki, Iyad Alhayek
  • Patent number: 5632909
    Abstract: A full duplex radio having improved properties is obtained by using asymmetric surface acoustic wave (SAW) filters, the filters are composed of series and parallel coupled SAW resonators. Asymmetry is obtained by covering either of the series or parallel resonators of each filter with a dielectric layer to increase the SAW coupling coefficient of the covered resonators relative to the uncovered resonators. The filters are desirably in pairs arranged with mirror image frequency asymmetry such that the steeper skirts of the frequency response are adjacent. Greater pass-bandwidths can be obtained without adverse affect on transmitter and receiver isolation.
    Type: Grant
    Filed: June 19, 1995
    Date of Patent: May 27, 1997
    Assignee: Motorola, Inc.
    Inventors: Donald E. Allen, Philip P. Kwan, David P. Stumbo
  • Patent number: 5618326
    Abstract: The surface quality of halide, preferably fluoride, articles, e.g. articles used in the preparation of halide fibres is improved by cleaning the surface with an aqueous etchant and thereafter removing the etchant by washing the surface with methanol. The aqueous etchant is preferably a solution which contains hydrochloric acid and zirconium oxychloride.
    Type: Grant
    Filed: March 22, 1995
    Date of Patent: April 8, 1997
    Assignee: British Telecommunications public limited company
    Inventors: Daryl Szebesta, John R. Williams, Steven T. Davey
  • Patent number: 5618448
    Abstract: Disclosed herein is a substrate for a magnetic disc comprising a glass substrate having fine protrusions on its surface, the protrusions having a height of 50 to 1000 .ANG., a width of 0.01 to 1 .mu.m, a density of 10 to 1000 per 100 .mu.m.sup.2 and an area ratio of 0.1 to 50%, and a ratio of peak height on a mean line (R.sub.p) to maximum height (R.sub.max) with respect to surface roughness of the substrate being at least 60%. Further, a process for preparing the substrate and a magnetic disc having the substrate are disclosed. Because the substrate according to the present invention has appropriate protrusions on its surface, a friction force and an adsorbing force between a head and a magnetic disc can be reduced, leading to the improvement of the CSS and the anti-head stick properties. In addition, the S/N ratio is not affected because the fine concave portions formed on the surface of the substrate are shallow.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: April 8, 1997
    Assignee: Mitsubishi Kasei Corporation
    Inventors: Toru Kuroe, Fumiaki Yokoyama, Daisuke Mouri
  • Patent number: 5589084
    Abstract: A thin film actuated mirror for an actuated mirror array includes a pedestal and at least piezoelectric structure cantilevered from the pedestal. The piezoelectric structure includes a layer of piezoelectric material having two opposing surfaces. Each of two metal electrodes are mounted on a respective one of the opposing surfaces of the piezoelectric material layer. An electrical signal is applied across the piezoelectric material, between the electrodes, causing deformation of the piezoelectric material. The thin film actuated mirror further includes a mirror surface interconnected to the piezoelectric material layer such that the mirror surface deforms in response to the deformation of the piezoelectric material layer.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: December 31, 1996
    Assignees: Daewoo Electronics Co. Ltd., Aura Systems, Inc.
    Inventors: Jeong B. Ji, Gregory Um
  • Patent number: 5585011
    Abstract: The fluid handling devices are capable of accurately handling substantially continuous fluid flow rates as low as about 0.01 cc/day. The devices are so miniaturized, corrosion-resistant and non-toxic that they are suitable for being implanted in the human body; and are capable of being mass produced at costs so low, by using micromachining techniques, such as etching, that they may be considered to be disposable. The devices are either passive devices which consume no electrical energy at all, or are active devices which consume very small amounts of electrical energy. The devices are reliable because they may have as few as only two parts, only one which is a moving part; and because they may handle fluids at very low pressures. The fluid handling devices include active piezoelectrically driven membrane pumps; and passive fluid flow regulators, on-off valves, flow switches and filters.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: December 17, 1996
    Assignee: Research International, Inc.
    Inventors: Elric W. Saaski, Dale M. Lawrence
  • Patent number: 5562839
    Abstract: A low-cost, high performance 1.times.N fiber optic coupler where N>16 is presented. The coupler has a GRIN lens having an first optic fiber aligned with the optical axis of the lens at one end of the lens. The first optic fiber ends in a microlens. At the other end of the GRIN lens a bundle of tapered second optic fibers is centered on the optical axis of the lens.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: October 8, 1996
    Assignee: E-Tek Dynamics, Inc.
    Inventor: Jing-Jong Pan
  • Patent number: 5531343
    Abstract: This invention involves a fiber probe device and a method of making it. The probe includes a relatively thick upper cylindrical region, typically in the form of a solid right circular cylinder, terminating in a tapered region that terminates in a relatively thin lower cylindrical region (tip), typically also in the form of a solid right circular cylinder, the lower region having a width (diameter) in the approximate range 0.01 .mu.m to 150 .mu.m.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: July 2, 1996
    Assignee: AT&T Corp.
    Inventors: Robert W. Filas, Herschel M. Marchman
  • Patent number: 5520299
    Abstract: This is a system and method of etching pyroelectric devices post ion milling. The method may comprise: forming a mask 32 for thermal isolation trenches on a substrate 14; ion milling thermal isolation trenches 40 in the substrate 14; and etching undesired defects 44 caused by the ion milling by applying a dry etch, a solvent etch, or a liquid etch to the trenches. The etch may include: hydrofluoric acid, perchloric acid, a solution of a chlorine salt and water which is then exposed to ultraviolet light or any similar chemical solution giving the correct reducing properties. The mask 32 and ion milling may be applied from either the front side or the back side of the infrared detector.
    Type: Grant
    Filed: February 15, 1995
    Date of Patent: May 28, 1996
    Assignee: Texas Instruments Incorporated
    Inventors: James F. Belcher, Howard R. Beratan
  • Patent number: 5480049
    Abstract: A fiber probe device includes a fiber segment that has at least three sections. An uppermost section has the largest diameter; an intermediate section has an intermediate diameter, and a lowest section (tip) has the smallest diameter. The presence of the intermediate section enables control over the stiffness of the section located immediately above the tip as well as control over the mechanical resonance characteristic of the probe device when it scans a sample surface to be measured.
    Type: Grant
    Filed: August 26, 1994
    Date of Patent: January 2, 1996
    Assignee: AT&T Corp.
    Inventor: Herschel Maclyn Marchman
  • Patent number: 5480046
    Abstract: A probe device is fabricated from a glass fiber segment by first isotropically etching only a portion of the diameter of only a bottom region thereof. Next, the bottom region is cleaved, to produce a cleaved bottom endface. Then the cleaved endface and a height of the sidewalls of the bottom region that is less than its total height are coated with a protective masking layer. The fiber segment is immersed in an isotropic etching solution, whereby its diameter is reduced. Finally, the masking layer is stripped off, and the bottom region is etched again until the (maximum) diameter of the cleaved endface is reduced to a desired value.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: January 2, 1996
    Assignee: AT&T Corp.
    Inventors: Robert W. Filas, Herschel M. Marchman
  • Patent number: 5456372
    Abstract: A component for a laminated window, the component comprising a glass sheet having an etched hydrated surface and a protective layer of plastics material covering the etched surface, the protective layer being selected so as to be bondable to a plastics interlayer material. The invention also provides a laminated window including a first ply comprising a glass sheet having an etched hydrated surface and a protective layer of plastics material covering the etched surface and a second ply to which the first ply is bonded by a plastics interlayer, the material of the interlayer and of the protective layer being selected so as to be bondable together. The present invention further provides a method of producing a pre-product glass sheet having improved bending strength.
    Type: Grant
    Filed: November 18, 1994
    Date of Patent: October 10, 1995
    Assignee: Flachglas Intg Glasveredelungs GmbH
    Inventors: Vladimir Solinov, Igor Boguslavski
  • Patent number: 5435888
    Abstract: A method for planarizing integrated circuit topographies, wherein, after a first layer of spin-on glass is deposited, a layer of low-temperature oxide is deposited before a second layer of spin-on glass.
    Type: Grant
    Filed: December 6, 1993
    Date of Patent: July 25, 1995
    Assignee: SGS-Thomson Microelectronics, Inc.
    Inventors: Alex Kalnitsky, Yih-Shung Lin
  • Patent number: 5425847
    Abstract: Method of removing a layer of glass formed on a sintered body which is manufactured by hot isostatic pressing of a preformed body of inorganic powder in a pressure medium at a sintering temperature, wherein the sintered body of inorganic powder is retained in an alkali solution of at least 2 percent by weight at a temperature not less than 100.degree. C. for not less than one hour.
    Type: Grant
    Filed: September 3, 1993
    Date of Patent: June 20, 1995
    Assignee: NGK Insulators, Ltd.
    Inventors: Akira Narukawa, Mitsuyoshi Watanabe
  • Patent number: 5415731
    Abstract: A method of preparing a non-glare glass comprising (a) applying a printing ink consisting of water, sugar, carboxymethyl cellulose, starch powder, and aluminum oxide on the surface of the glass by means of a conventional screen printing technique; (b) dipping the glass into a dipping solution consisting of water, sugar, ammonium bifluoride, and ferric chloride; and (c) washing the glass thus treated with water. The resulting glass has a number of fine, transparent, etched patterns on its surface, and thus, can scatter light applied to the surface in a random manner, resulting in a non-glare surface. The process produces a glass having a non-glare surface, on which various and exquisite patterns are etched, without causing environmental pollution or injury to workers.
    Type: Grant
    Filed: February 10, 1994
    Date of Patent: May 16, 1995
    Assignees: Jung Hyung Kim, Hyang Wung Kim
    Inventor: Jung H. Kim