EP0123891B1 - Verfahren zum Formen einer Sammellinse in einer Platte aus einem transparenten, mineralischen Material - Google Patents

Verfahren zum Formen einer Sammellinse in einer Platte aus einem transparenten, mineralischen Material Download PDF

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Publication number
EP0123891B1
EP0123891B1 EP84103309A EP84103309A EP0123891B1 EP 0123891 B1 EP0123891 B1 EP 0123891B1 EP 84103309 A EP84103309 A EP 84103309A EP 84103309 A EP84103309 A EP 84103309A EP 0123891 B1 EP0123891 B1 EP 0123891B1
Authority
EP
European Patent Office
Prior art keywords
axis
lens
plate
grinding member
radius
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
Application number
EP84103309A
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English (en)
French (fr)
Other versions
EP0123891A2 (de
EP0123891A3 (en
Inventor
Claude-Michel Juvet
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.)
Comadur SA
Original Assignee
Comadur SA
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
Application filed by Comadur SA filed Critical Comadur SA
Publication of EP0123891A2 publication Critical patent/EP0123891A2/de
Publication of EP0123891A3 publication Critical patent/EP0123891A3/fr
Application granted granted Critical
Publication of EP0123891B1 publication Critical patent/EP0123891B1/de
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B24B13/04—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor grinding of lenses involving grinding wheels controlled by gearing

Definitions

  • the present invention relates to a method for forming a round converging lens and included in the thickness of a plate of a transparent mineral material.
  • US-A 3,905,163 describes a method for machining lenses in the thickness of the plate.
  • each lens is formed by first digging a groove which surrounds the part of the plate intended to comprise it, then machining the lens by successive grindings, to rough it, form it, then polish it.
  • the lenses thus produced are large, which is not the case for example when the plate is a watch glass.
  • the object of the present invention is to remedy this drawback.
  • the oscillating movement is controlled in synchronism with the rotation movement of the plate around the second axis, thanks to a cam secured to the support of the plate, which cooperates with a finger secured to the frame of the machine. .
  • This oscillating movement is to move the grinding wheel relative to the center of the plate, to define the outline of the converging lens, the shape of which is advantageously non-circular.
  • the grinding wheel must have a diameter sufficient to sweep the entire surface to be machined at each revolution of the plate.
  • the method is not intended to form a converging lens included in the thickness of a plate. In addition, it does not achieve the goal defined above.
  • the oscillation angle must be at least equal to the angle corresponding to the difference between half of the arc embraced by the lens and the arc embraced by the active part of the grinding wheel.
  • the device shown in Figure 1 comprises a support frame 10 on which are mounted a bracket 12 and a headstock 14.
  • the bracket 12 carries a pin 16 at the end of which is fixed a cylindrical grinding wheel 20, of the same axis as the spindle and carrying, at its active end 20a, abrasive material, preferably consisting of diamond powder.
  • a pulley 18, mounted on the spindle 16, makes it possible to drive the latter in rotation by means of a motor not shown.
  • the bracket 12 further comprises slides 22, 24 and 26 allowing, in a completely conventional manner, the movement of the grinding wheel 20 along three orthogonal axes. More specifically, the slide 22 allows, using a micrometric screw 23, to move the grinding wheel vertically along its axis, while the slides 24 and 26 allow, using the micrometric screws 25 and 27 respectively , to move the grinding wheel horizontally in two perpendicular directions.
  • the headstock 14 carries a spindle 28 whose end 28a adjacent to the bracket 12 is, by virtue of an elbow 28b, offset downward relative to the axis of rotation of the spindle.
  • a table 30 is mounted on a shaft 32 which is perpendicular to the axis of the spindle 28 and which pivots in the end 28a. This shaft carries a pulley 34 which makes it possible to drive it in rotation, thanks to a motor not shown in the figure.
  • a fitting 36, integral with the table 30, makes it possible to fix a plate 38, made of transparent mineral material, such as a watch glass, intended to be provided with a lens.
  • the fitting 36 has a thickness such that the distance between the upper face of the plate 38 and the axis of the spindle 28 is equal to the radius of curvature R that the lens should have.
  • the spindle 28 is associated with drive means, not shown, allowing it to impart an oscillating movement of low amplitude.
  • the active part 20a of the grinding wheel has, as shown in FIGS. 2a and 2b, a form of concave spherical cap, of radius equal to the radius of curvature of the lens.
  • the axis 40 of the shaft 32 and the axis 42 of the spindle 16 coincide when the plate 38 is horizontal ( Figure 2a). In the other positions of the plate, these two axes intersect the axis of the spindle 28, shown at 44 and form an angle a whose maximum value ⁇ max corresponds to the extreme positions of the plate.
  • the oscillating movement of the spindle 28 it is possible to increase the time between two sharpenings of the grinding wheel.
  • the oscillation movement is made possible by the fact that the diameter D of the lens is substantially greater than that of the grinding wheel.
  • the d / D ratio is between 1/3 and 2/3.
  • the relationship between the angle a max , the diameters D and d and the radius of curvature R can be expressed by the formula: This relation is used to define the maximum amplitude of the oscillating movement of the spindle, which makes it possible to produce, using a grinding wheel of given diameter, a lens of desired diameter and radius of curvature.
  • the angle a max is between 5 and 20 ° approximately.
  • this maximum amplitude is equivalent to an oscillation such that a varies from + Qmax to -a max '
  • the oscillation must have a minimum amplitude, between a max and a mln , a min being equal to a max minus the difference of the angles associated with half of the arc embraced by the lens and the arc kissed by the millstone.
  • the axes 40 and 42 of the shaft 32 and of the spindle 16 define a plane, coinciding with the plane of these figures and perpendicular to the axis 44 of spindle 28.
  • the axis 42 of spindle 16 is spaced from axis 44 by a value e.
  • the plate 38 is horizontal (FIG. 3a)
  • the axes of the spindle 16 and of the shaft 32 are parallel.
  • the two axes form an angle a, the maximum value a max of which is obtained when the spindle 28 is at its maximum oscillation (FIG. 3b).
  • the shape of the end 20a of the grinding wheel is, in this case, a part of a torus whose radius of the generating circle is equal to the radius of curvature R of the lens and whose distance between the generating axis and the center of the circle generator is equal to e.
  • This mode of operation allows the use of a wheel of larger diameter, hence an increase in its service life, due to lower wear.
  • the adjustment of the device is however more delicate.
  • the rules relating to the minimum amplitude of the oscillation are also applicable in this variant, with the difference however that for the same diameter, the arc embraced by the active part of the grinding wheel is substantially equal to half of that corresponding to the first variant, because the active part has the shape of a torus part and no longer a sphere cap.
  • connection cone would have a large angle at the top, which would be unsightly.
  • This drawback can be eliminated by using a grinding wheel whose active part 20a, in the form of a torus part, is connected to the body of the grinding wheel by a truncated cone 20b whose angle at the top is equal to 2 amax.
  • the parts 20a and 20b can be produced independently of the body of the grinding wheel, and then fixed to the latter by conventional connecting means. Thanks to the fact that the angle a max is important, the central area of the concave torus portion is prominent and can thus easily be truncated to allow access to the assembly means not shown in the drawing.
  • the oscillation movement is imposed on the table carrying the plate. It goes without saying that if it is the grinding wheel which oscillates, around the same axis 44, the effect obtained is identical.
  • This process lends itself particularly well to the machining of sapphire plates, but also to other materials, such as mineral glass for example.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)

Claims (5)

1. Verfahren zum Formen einer runden Sammellinse in der Dicke einer Platte aus einem transparenten, mineralischen Material, dadurch gekennzeichnet, dass es darin besteht, gleichzeitig
-eine Drehung der genannten Platte zum eine erste Achse zu bewirken, die rechtwinklig zu der Zone liegt, in der die genannte Linse geformt werden muss, und durch die Mitte dieser Zone verläuft;
-ein Schleifen der genannten Zone mittels einer Schleifscheibe zu bewirken, deren aktiver Teil einen kleineren Durchmesser aufweist als der Durchmesser der Linse und sich um eine zweite Achse dreht;
-eine oszillierende Bewegung der Platte oder der Schleifscheibe um eine dritte Achse zu bewirken, die rechtwinklig zu der die erste und zweite Achse enthaltenden Ebene liegt, die genannte erste Achse schneidet und von der genannten Zone um einen Wert entfernt ist, der gleich dem gewünschten Krümmungsradius der Linse ist; und
-auf unabhängige Weise die Antriebsmittel zur Drehung der Platte um die erste Achse und die Antriebsmittel zur oszillierenden Bewegung der Platte oder der Schleifscheibe um die dritte Achse zu steuern.
2. Verfahren gemäss Anspruch 1, dadurch gekennzeichnet, dass die zweite Achse die dritte Achse schneidet, und dass der aktive Teil der genannten Schleifscheibe eine konkave Kugelkuppe besitzt, deren Radius gleich dem Krümmungsradius der Linse ist.
3. Verfahren gemäss Anspruch 1, dadurch gekennzeichnet, dass die zweite und dritte Achse voneinander um einen konstanten Wert über Null entfernt sind und dass der aktive Teil der Schleifscheibe die Form eines konkaven Torusteils besitzt, dessen Generationsachse mit der genannten zweiten Achse konizidiert, dessen Generationskreisradius gleich dem Krümmungsradius der Linse ist und dessen Abstand zwischen der Generationsachse und der Mitte des Generationskreises gleich dem Abstand zwischen der zweiten und dritten Achse ist.
4. Verfahren gemäss Anspruch 3, dadurch gekennzeichnet, dass der Durchmesser d der Schleifscheibe, der Durchmesser D der Linse und der durch die erste und zweite Achse gebildete maximale Winkel amax. folgender Ungleichung entsprechend: D cos amax≧d.
5. Verfahren gemäss Anspruch 4, bei dem die genannte Schleifscheibe einen Körper zylindrischer Form aufweist, dadurch gekennzeichnet, dass der genannte Körper mit dem aktiven Teil der Schleifscheibe über einen Kegelstumpf verbunden ist, dessen schmalerer Teil am genannten Körper liegt, wobei der Scheitelwinkel des genannten Kegels gleich 2 amax ist.
EP84103309A 1983-03-31 1984-03-26 Verfahren zum Formen einer Sammellinse in einer Platte aus einem transparenten, mineralischen Material Expired EP0123891B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1800/83A CH651773A5 (fr) 1983-03-31 1983-03-31 Procede pour former une lentille convergente dans une plaque d'un materiau mineral transparent.
CH1800/83 1983-03-31

Publications (3)

Publication Number Publication Date
EP0123891A2 EP0123891A2 (de) 1984-11-07
EP0123891A3 EP0123891A3 (en) 1986-02-05
EP0123891B1 true EP0123891B1 (de) 1988-05-18

Family

ID=4218896

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84103309A Expired EP0123891B1 (de) 1983-03-31 1984-03-26 Verfahren zum Formen einer Sammellinse in einer Platte aus einem transparenten, mineralischen Material

Country Status (6)

Country Link
US (1) US4584799A (de)
EP (1) EP0123891B1 (de)
JP (1) JPS59187449A (de)
CH (1) CH651773A5 (de)
DE (1) DE3471270D1 (de)
SG (1) SG38991G (de)

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JPS62114866A (ja) * 1985-11-08 1987-05-26 Matsushita Electric Ind Co Ltd 非球面加工機
EP0257013B1 (de) * 1986-08-19 1992-01-02 Léon Biebuyck Verfahren und Vorrichtung zum mechanischen Schleifen und Polieren der Fläche eines mineralischen Materials, insbesondere aus Glas
US4956944A (en) * 1987-03-19 1990-09-18 Canon Kabushiki Kaisha Polishing apparatus
JPH0659613B2 (ja) * 1988-10-20 1994-08-10 オリンパス光学工業株式会社 研削研磨装置及び研削研摩方法
DE69827768D1 (de) 1998-04-02 2004-12-30 Comadur Sa Uhrglas mit einer Linse und Verfahren zur Herstellung einer solchen Linse
JP4288012B2 (ja) * 2001-01-05 2009-07-01 株式会社ニデック 眼鏡レンズ加工装置
EP1424163A1 (de) * 2002-11-26 2004-06-02 Comadur S.A. Rotierendes Werkzeug zum Bearbeiten einer Form auf einem mineralischen Material, wie dem Saphir, insbesondere zum Bearbeiten einer optischen Fläche auf einem Uhrglas
US7083326B2 (en) * 2004-09-13 2006-08-01 Ast Ryan C Adjustable watch crystal apparatus
ATE504515T1 (de) * 2006-01-25 2011-04-15 Guala Closures Spa Originalitätsverschluss für flaschen enthaltend wertvolle getränke
CN109865764B (zh) 2012-02-16 2021-05-14 苹果公司 由刚性材料形成的联锁柔性片段
US10086484B2 (en) 2012-10-12 2018-10-02 Apple Inc. Manufacturing of computing devices
JP6006144B2 (ja) * 2013-02-27 2016-10-12 オリンパス株式会社 レンズ加工装置、レンズ加工方法、及びレンズ加工用工具
DE102014003598B4 (de) * 2014-03-17 2020-02-27 Satisloh Ag Vorrichtung zum Schleifen, Feinschleifen und/oder Polieren von Werkstücken in optischer Qualität, insbesondere von sphärischen Linsenflächen in der Feinoptik
US9852723B2 (en) 2014-03-27 2017-12-26 Apple Inc. Acoustic modules
US10335979B2 (en) 2014-09-30 2019-07-02 Apple Inc. Machining features in a ceramic component for use in an electronic device
US10071539B2 (en) 2014-09-30 2018-09-11 Apple Inc. Co-sintered ceramic for electronic devices
US10207387B2 (en) 2015-03-06 2019-02-19 Apple Inc. Co-finishing surfaces
US10216233B2 (en) 2015-09-02 2019-02-26 Apple Inc. Forming features in a ceramic component for an electronic device
US10542628B2 (en) 2017-08-02 2020-01-21 Apple Inc. Enclosure for an electronic device having a shell and internal chassis

Family Cites Families (14)

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Publication number Priority date Publication date Assignee Title
US1515681A (en) * 1919-05-02 1924-11-18 American Optical Corp Lens grinder
US1491383A (en) * 1921-05-31 1924-04-22 American Optical Corp Lens-grinding apparatus
US1563918A (en) * 1922-08-02 1925-12-01 American Optical Corp Method of grinding lenses
US2087687A (en) * 1934-07-27 1937-07-20 Daniel D Hubbell Apparatus for producing one-piece multifocal ophthalmic lenses
GB449398A (en) * 1934-12-21 1936-06-22 James Alfred Moore Improvements in the process of grinding curved surfaces, and apparatus therefor
US2336322A (en) * 1940-02-23 1943-12-07 Uhlemann Optical Co Of Illinoi One-piece plurifocal lens
FR977720A (fr) * 1942-10-21 1951-04-04 Verreries De Bagneaux Et Apper Procédé et appareil pour le surfaçage de corps sphériques, en particulier de verres d'optique
IT454428A (de) * 1949-04-21
US2747339A (en) * 1954-01-18 1956-05-29 Bausch & Lomb Lens grinding machine
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US2977724A (en) * 1959-08-24 1961-04-04 Textron Inc Lens surfacing machine
US3905163A (en) * 1974-03-06 1975-09-16 Tropel Lens making method
SU865619A1 (ru) * 1980-01-07 1981-09-23 Предприятие П/Я Г-4671 Способ обработки асферических поверхностей оптических деталей
CA1201579A (en) * 1981-03-05 1986-03-11 Yoshiaki Nagaura Lens-shaped article or the like and a method and apparatus for the manufacture of the same

Also Published As

Publication number Publication date
SG38991G (en) 1991-07-26
US4584799A (en) 1986-04-29
CH651773A5 (fr) 1985-10-15
DE3471270D1 (en) 1988-06-23
EP0123891A2 (de) 1984-11-07
JPS59187449A (ja) 1984-10-24
EP0123891A3 (en) 1986-02-05

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