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US3764770A - Microwave oven - Google Patents

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Publication number
US3764770A
US3764770A US00249880A US3764770DA US3764770A US 3764770 A US3764770 A US 3764770A US 00249880 A US00249880 A US 00249880A US 3764770D A US3764770D A US 3764770DA US 3764770 A US3764770 A US 3764770A
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US
United States
Prior art keywords
oven
opening
enclosure
waveguide
defining
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00249880A
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English (en)
Inventor
T Saad
M Miller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MICRO-QUARTZ TECHNOLOGY Corp 1010 LYNDALE AVE NORTH MINNEAPOLIS MN 55141 A CORP OF
SAGE LABOR INC US
SAGE LABORATORIES
Original Assignee
SAGE LABORATORIES
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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Application granted granted Critical
Publication of US3764770A publication Critical patent/US3764770A/en
Assigned to MICRO-QUARTZ TECHNOLOGY CORPORATION, A CORP. OF MN. reassignment MICRO-QUARTZ TECHNOLOGY CORPORATION, A CORP. OF MN. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MICRO-TRONICS, LTD. A CORP. F MN.
Assigned to MICRO-QUARTZ TECHNOLOGY CORPORATION 1010 LYNDALE AVE., NORTH MINNEAPOLIS, MN 55141 A CORP. OF MN reassignment MICRO-QUARTZ TECHNOLOGY CORPORATION 1010 LYNDALE AVE., NORTH MINNEAPOLIS, MN 55141 A CORP. OF MN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MICRO-TRONICS, LTD., INC. A MN CORP.
Assigned to MICRO-TRONICS, LTD., INC., 1010 LYNDALE AVE. NORTH, MINNEAPOLIS, MN 55141 A CORP. OF reassignment MICRO-TRONICS, LTD., INC., 1010 LYNDALE AVE. NORTH, MINNEAPOLIS, MN 55141 A CORP. OF ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MICRO-TRONICS, INC. A WI CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/70—Feed lines
    • H05B6/705—Feed lines using microwave tuning
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/6402—Aspects relating to the microwave cavity
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/74—Mode transformers or mode stirrers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

  • a quarter wavelength transformer intercouples the waveguide and the top of the cavity, [22] (ii. 2l9/l0.55, 333/35 and the waveguide dimensions and operating 1] nt. C H05b 9/06 quency are preselected so h t preferably only the of Search dominant TEL mode is excited.
  • the transformer properly matches the waveguide with the cavity di- [56] References cued mensions and, when the food load is disposed in the UNITED STATES PATENTS oven, the dominant mode is established in the cavity 3,560,694 2/1971 White 219/1055 thereby causing predictable and relatively uniform 3,670,134 6/1972 Bucksbaum Weghoff etc.
  • the present invention relates in general to microwave heating or cooking ovens. More particularly, the present invention is concerned with an improved microwave oven construction wherein the cooking or heating cavity has primarily only the dominant TE mode established therein.
  • the cavity is conceptually considered as a second waveguide with the food in the oven functioning as a termination for the waveguide.
  • a matching quarter wave transformer between the waveguide coupling from the magnetron and the cavity waveguide and operating at the appropriate microwave frequency it has been possible to excite primarily only the dominant TE mode within the cavity.
  • the E field heating pattern established in the cavity when operating in the dominant mode is relatively uniform over a useable area of the cavity specifically about the middle of the cavity. Also, with the structure in accordance with the teachings of the present invention there is no need for providing mode stirrers and it is preferred that they not be used.
  • Another object of the present invention is to provide an improved microwave oven construction in accordance with the preceding object wherein the heating pattern is predictable and relatively uniform over a useable area of the oven.
  • a further object of the present invention is to provide an improved microwave oven construction that is relatively simple to fabricate and is less expensive to manufacture than presently available microwave ovens.
  • Still another object of the present invention is to provide an improved microwave oven construction wherein existing ovens may be relatively easily modified to incorporate the teachings of the present invention.
  • the microwave oven of the present invention comprises a conductive box-shaped structure defining a cavity, including means for supporting a load within the cavity, and having an opening preferably at the top thereof for receiving the microwave energy.
  • the oven further comprises a source of microwave energy such as a magnetron and a rectangular waveguide positioned to receive energy from the source for transmission through the waveguide.
  • the frequency of operation of the microwave energy source and the cross-sectional dimensions of the waveguide are selected so as to excite primarily only the dominant TE mode in the waveguide.
  • a quarter wavelength transformer having one or more steps couples from the other end of the waveguide to the opening into the cavity and is constructed symmetrically so as to enable the establishment of the dominant TE mode when a load is present in the cavity.
  • the waveguide has a 1.7 inches X 3.4 inches crosssectional dimension
  • the cavity has a 12 inches X 12 inches cross-section and three, quarter wavelength, steps are used as the matching transformer between the waveguide and the open top of the cavity.
  • the top of the box-shaped structure defining the cavity has a rectangular opening dimensioned to receive the end of the waveguide and an effective transformer is provided by extending a rectangular sleeve downwardly from the inner surface of the top of the structure. This sleeve is disposed intermediate the opening for the waveguide and the outer walls of the structure at the appropriate symmetrical position to provide the proper quarter wavelength match.
  • the sleeve hereinbefore referred to may be annular in configuration, or either of the sleeve configurations may be replaced by spaced posts disposed along the locus of either the rectangular or annular sleeve.
  • the waveguide enters the structure from the side and a conductive strap extends from the bottom edge of the waveguide curving upwardly to contact the top of the structure or may be spaced from the top thereof to form effectively an inductive or capacitive coupling.
  • FIG. 1 is a partially cut-away perspective view of a preferred embodiment of the microwave oven of the present invention
  • FIG. 2 is a cross-sectional view through the oven of FIG. 1 taken along line 2-2;
  • FIG. 3 is a cross-sectional view through the oven of FIG. 1 taken along line 3-3;
  • FIG. 4 is a perspective view of another embodiment of the present invention specifically showing the inner upper oven construction
  • FIG. 5 shows another embodiment of the present invention using an annular matching transformer
  • FIG. 6 is still another embodiment of the present invention employing a plurality of spaced posts
  • FIG. 7 is an embodiment of the invention wherein the power feed is from the side rather than the top of the oven
  • FIG. 8 is a cross-sectional view through an oven similar to the one shown in FIG. 7;
  • FIG. 9 is a perspective view of another arrangement for the waveguide feed of FIGS. 7 or 8.
  • FIG. 1 is a partially cut-away perspective view and FIGS. 2 and 3 are orthogonal cross-sections taken along lines 2-2 and 33, respectively, of FIG. 1.
  • the enclosure is constructed of a metal such as aluminum or stainless steel and includes side walls 16 and 18, back wall 20, top wall 22, bottom wall 24, and door 26 having handle 28 for enabling access thereto.
  • a food retaining screen or tray may be disposed on bottom wall 24 as depicted in FIG. 2.
  • the transformer 12 comprises three steps 32, 34 and 36 which may be constructed by extrusion molding in a single piece. In one embodiment the walls of each step are three-eighths inch thick.
  • the step 32 is characterized by the dimensions L H, and W,.
  • the waveguide 14 is of conventional 1.7 X 3.4 inch size.
  • the steps 34 and 36 are characterized by the dimensions L H and W and L H and W respectively.
  • the dimensions W, and H, of the enclosure 10 are both 12 inches.
  • the microwave energy is coupled from a typical magnetron tube via waveguide 14 and transformer 12 to the enclosure 10 to thereby establish the fundamental TE, mode in the oven.
  • FIG. 4 shows another embodiment of the present invention including oven enclosure 40 which may be substantially the same as enclosure 10 of FIG. 1, and waveguide 42 which may be a typical rectangular waveguide of 1.7 X 3.4 inch dimensions.
  • the matching means in this embodiment includes a rectangular ridge 44 which depends downwardly from top wall 46 of the enclosure.
  • the dimensions H and W of the ridge are calculated to be 4.70 inches and 6.56 inches, respectively.
  • the L dimension is on the order of 1.3 inches.
  • FIG. 5 shows another embodiment of the invention including enclosure 50, waveguide 52 and annular matching ridge 54 which depends downwardly from top wall 56 of the oven.
  • the ridge 54 may have a diameter on the order of 5.5 inches and may extend downwardly about 1.3 inches. In an alternate arrangement the ridge 54 may be elliptical in shape.
  • annular ridge 54 has been replaced by a series of posts 58 extending downwardly from top wall 59 of the enclosure. These posts are disposed along the locus defined by ridge 54 and in the disclosed embodiment there are eight posts. These posts may extend downwardly about 1.3 inches.
  • FIG. 7 The embodiment shown in FIG. 7 is different from those previously discussed in that the waveguide 60 couples into a side wall 62 of enclosure 64.
  • a relatively rigid strap 66 extends from wall 62 at the bottom edge 68 of the waveguide, and the strap has an upturned end 70 fixed at point 72 to approximately the midpoint of top wall 74.
  • the fixing at point 72 may be provided by a screw extending through a loop in the end 70 and mating in a tapped hole in wall 74.
  • Strap 66 may be replaced by a wire mesh or by a series of spaced rods.
  • FIG. 8 shows a cross-sectional view through another embodiment of the invention quite similar to the one disclosed in FIG. 7.
  • the strap 80 has an upturned end 82 that does not attach to top wall 84 but instead defines with wall 84 a gap 86.
  • the tap 86 may be 0.5 inches wide.
  • Tests have been conducted with the oven of the present invention and also with commercially available ovens to determine the heating uniformity within a useable portion of the oven.
  • a temperature tray such as the one disclosed in copending patent application Ser. No. 214,095 has been employed.
  • the tray includes 25 separate sensing compartments arranged in a 5 X 5 matrix.
  • Tables I and II show the temperature pattern measured when using the oven of the present invention and another commercially avai ab x wqt
  • the numbers shown in Tables I and II indicate the temperature rise measured in the corresponding compartment of the temperature tray when the tray is filled with a predetermined amount of water and the oven is operated for a predetermined time interval. Usually the initial temperature in all compartments is about 70.
  • the Table I readings were taken using the embodiment of FIG. 4 of the present invention.
  • the ratio R is not that critical and generally any value of 4.0 or less is suitable. The most critical ratio is probably ratio R This ratio indicates that for case I (Table l) 52 percent of the total heat measured in the 25 boxes is concentrated in the center nine boxes where the majority of the food would be located, and where the heat is thus desired. Alternatively, in case 11 (Table II) only 26 percent of the total heat is concentrated in the center boxes. The ratio R, is approximately the same in both cases.
  • a microwave oven comprising;
  • a waveguide of predetermined cross-section positioned with one end receiving energy from said source for transmission through said waveguide
  • the frequency of operation of said source and the cross-sectional dimension of said waveguide being selected to excite the TE mode in said waveguide
  • means defining an enclosure including means for providing access to the enclosure and means defining an opening into the enclosure,
  • said matching means includes a quarter wavelength step transformer and said enclosure has means for supporting a load provided therein.
  • said matching means includes a continuous ridge depending from the wall of the enclosure defining the opening and disposed intermediate the edge of the opening and another wall defining the enclosure.
  • said matching means comprises a plurality of spaced posts depending from the wall of the enclosure defining the opening and disposed along a circular path about said opening.
  • said matching means comprises a plurality of spaced posts depending from the wall of the enclosure defining the opening and disposed along an elliptical path about said opening.
  • said matching means comprises a plurality of spaced posts depending from the wall of the enclosure defining the opening and disposed along a rectangular path about said opening.
  • said means defining an enclosure includes a pair of oppositely disposed walls one of which defines said opening.
  • the oven of claim 14 including strap means coupling from an edge defining said opening to a top wall defining said enclosure.
  • the oven of claim 14 including strap means coupling from an edge defining said opening to adjacent a top wall defining said enclosure, defining a gap between said strap means and top wall.
  • the oven of claim 16 including means disposed adjacent the opening for adjusting in a vertical direction the position of said strap means.
  • the oven of claim 17 including means disposed adjacent the opening for adjusting in a vertical direction the position of said strap means.
  • a microwave oven comprising a source of microwave energy

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Constitution Of High-Frequency Heating (AREA)
US00249880A 1972-05-03 1972-05-03 Microwave oven Expired - Lifetime US3764770A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US24988072A 1972-05-03 1972-05-03

Publications (1)

Publication Number Publication Date
US3764770A true US3764770A (en) 1973-10-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00249880A Expired - Lifetime US3764770A (en) 1972-05-03 1972-05-03 Microwave oven

Country Status (8)

Country Link
US (1) US3764770A (de)
JP (1) JPS5313826B2 (de)
CA (1) CA952198A (de)
DE (1) DE2322036A1 (de)
FR (1) FR2183250B1 (de)
GB (1) GB1433505A (de)
NL (1) NL7306008A (de)
SE (1) SE391857B (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3975606A (en) * 1973-12-18 1976-08-17 Matsushita Electric Industrial Co., Ltd. Microwave oven with uniform electric field distribution
US3999026A (en) * 1974-02-22 1976-12-21 Stiftelsen Institutet For Mikrovagsteknik Vid Teknishka Hogskolan I Stockholm Heating device fed with microwave energy
US4144436A (en) * 1976-06-17 1979-03-13 General Electric Company Microwave oven excitation system for promoting uniformity of energy distribution
US4496814A (en) * 1983-01-10 1985-01-29 General Electric Company Microwave excitation system
US5272302A (en) * 1991-12-17 1993-12-21 Raytheon Company Microwave oven with improved cooking uniformity
WO1995031085A1 (en) * 1994-05-09 1995-11-16 Smeg S.P.A. A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven
EP0746182A3 (de) * 1995-05-31 1997-05-28 Rubbright Group Inc Rechteckiger Mikrowellenapplikator
US5786579A (en) * 1996-12-27 1998-07-28 Daewoo Electronics Co., Ltd. Microwave oven waveguide with mode transducer and differential mode absorber
US5880442A (en) * 1997-03-10 1999-03-09 Daewoo Electronics Co., Ltd. Microwave oven with structure for guiding electromagnetic wave
US5961871A (en) * 1991-11-14 1999-10-05 Lockheed Martin Energy Research Corporation Variable frequency microwave heating apparatus
RU2141746C1 (ru) * 1998-08-26 1999-11-20 Бродский Юрий Яковлевич Микроволновая печь
US6333496B1 (en) * 1997-02-13 2001-12-25 Whirlpool Corporation Microwave feeding of an oven cavity
WO2002023953A1 (en) * 2000-09-15 2002-03-21 Whirlpool Corporation Microwave oven and method in connection with the same
US20120024844A1 (en) * 2010-08-02 2012-02-02 Patrick Galbreath Device and implementation thereof for repairing damage in a cooking appliance

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55171556U (de) * 1979-05-29 1980-12-09
DE3022235C2 (de) * 1980-06-13 1982-10-21 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Mikrowellenheizgerät
DE3029035C2 (de) * 1980-07-31 1982-11-11 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Mikrowellenheizgerät
DE3120900A1 (de) * 1981-05-26 1983-06-16 Karl Dr. 7800 Freiburg Fritz Mikrowellen-arbeitsraum
FR2548507A1 (fr) * 1983-06-28 1985-01-04 Lambda Technics Int Applicateur a micro-ondes, a densite d'energie ajustable, destine au traitement d'objets au moins en partie polaires
KR850000580B1 (ko) * 1983-12-31 1985-04-29 주식회사 금성사 마이크로파 오븐의 균일가열 장치

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3019399A (en) * 1959-03-06 1962-01-30 Microwave Ass Circular waveguide diameter transformer
US3157845A (en) * 1963-01-29 1964-11-17 Gen Electric Rectangular to ridged waveguide transition having separate mode converting and impedance matching sections
US3560694A (en) * 1969-01-21 1971-02-02 Varian Associates Microwave applicator employing flat multimode cavity for treating webs
US3670134A (en) * 1971-01-26 1972-06-13 Amana Refrigeration Inc Microwave oven no-load sensor

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2814708A (en) * 1952-01-05 1957-11-26 Raytheon Mfg Co Microwave ovens
FR1373414A (fr) * 1962-10-26 1964-09-25 Philips Nv Four haute fréquence
GB1169166A (en) * 1966-01-03 1969-10-29 Microtherm Ltd Improvements in or relating to Heating Apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3019399A (en) * 1959-03-06 1962-01-30 Microwave Ass Circular waveguide diameter transformer
US3157845A (en) * 1963-01-29 1964-11-17 Gen Electric Rectangular to ridged waveguide transition having separate mode converting and impedance matching sections
US3560694A (en) * 1969-01-21 1971-02-02 Varian Associates Microwave applicator employing flat multimode cavity for treating webs
US3670134A (en) * 1971-01-26 1972-06-13 Amana Refrigeration Inc Microwave oven no-load sensor

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3975606A (en) * 1973-12-18 1976-08-17 Matsushita Electric Industrial Co., Ltd. Microwave oven with uniform electric field distribution
US3999026A (en) * 1974-02-22 1976-12-21 Stiftelsen Institutet For Mikrovagsteknik Vid Teknishka Hogskolan I Stockholm Heating device fed with microwave energy
US4144436A (en) * 1976-06-17 1979-03-13 General Electric Company Microwave oven excitation system for promoting uniformity of energy distribution
US4496814A (en) * 1983-01-10 1985-01-29 General Electric Company Microwave excitation system
US5961871A (en) * 1991-11-14 1999-10-05 Lockheed Martin Energy Research Corporation Variable frequency microwave heating apparatus
US5272302A (en) * 1991-12-17 1993-12-21 Raytheon Company Microwave oven with improved cooking uniformity
WO1995031085A1 (en) * 1994-05-09 1995-11-16 Smeg S.P.A. A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven
AU684024B2 (en) * 1994-05-09 1997-11-27 Smeg S.P.A. A device for homogenizing the distribution of radiatons within the cooking space of a microwave oven
EP0746182A3 (de) * 1995-05-31 1997-05-28 Rubbright Group Inc Rechteckiger Mikrowellenapplikator
US5828040A (en) * 1995-05-31 1998-10-27 The Rubbright Group, Inc. Rectangular microwave heating applicator with hybrid modes
US5786579A (en) * 1996-12-27 1998-07-28 Daewoo Electronics Co., Ltd. Microwave oven waveguide with mode transducer and differential mode absorber
US6333496B1 (en) * 1997-02-13 2001-12-25 Whirlpool Corporation Microwave feeding of an oven cavity
US5880442A (en) * 1997-03-10 1999-03-09 Daewoo Electronics Co., Ltd. Microwave oven with structure for guiding electromagnetic wave
RU2141746C1 (ru) * 1998-08-26 1999-11-20 Бродский Юрий Яковлевич Микроволновая печь
WO2000015019A3 (fr) * 1998-08-26 2000-05-25 Juri Yakovlevich Brodsky Four a micro-ondes
WO2002023953A1 (en) * 2000-09-15 2002-03-21 Whirlpool Corporation Microwave oven and method in connection with the same
US6884979B1 (en) * 2000-09-15 2005-04-26 Whirlpool Corporation Method and apparatus for uniform heating in a microwave oven
US20120024844A1 (en) * 2010-08-02 2012-02-02 Patrick Galbreath Device and implementation thereof for repairing damage in a cooking appliance
US8941039B2 (en) * 2010-08-02 2015-01-27 General Electric Company Device and implementation thereof for repairing damage in a cooking appliance

Also Published As

Publication number Publication date
JPS4954938A (de) 1974-05-28
FR2183250A1 (de) 1973-12-14
JPS5313826B2 (de) 1978-05-12
CA952198A (en) 1974-07-30
GB1433505A (en) 1976-04-28
NL7306008A (de) 1973-11-06
DE2322036A1 (de) 1973-12-13
FR2183250B1 (de) 1976-06-11
SE391857B (sv) 1977-02-28

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AS Assignment

Owner name: MICRO-QUARTZ TECHNOLOGY CORPORATION, A CORP. OF MN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MICRO-TRONICS, LTD. A CORP. F MN.;REEL/FRAME:004004/0072

Effective date: 19820603

Owner name: MICRO-QUARTZ TECHNOLOGY CORPORATION, 1010 LYNDALE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:MICRO-TRONICS, LTD. A CORP. F MN.;REEL/FRAME:004004/0072

Effective date: 19820603

AS Assignment

Owner name: MICRO-QUARTZ TECHNOLOGY CORPORATION 1010 LYNDALE A

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:MICRO-TRONICS, LTD., INC. A MN CORP.;REEL/FRAME:004024/0290

Effective date: 19820714

Owner name: MICRO-TRONICS, LTD., INC., 1010 LYNDALE AVE. NORTH

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:MICRO-TRONICS, INC. A WI CORP.;REEL/FRAME:004024/0294

Effective date: 19820603