WO2024120794A1 - Élément de miroir et procédé de production correspondant - Google Patents

Élément de miroir et procédé de production correspondant Download PDF

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Publication number
WO2024120794A1
WO2024120794A1 PCT/EP2023/082131 EP2023082131W WO2024120794A1 WO 2024120794 A1 WO2024120794 A1 WO 2024120794A1 EP 2023082131 W EP2023082131 W EP 2023082131W WO 2024120794 A1 WO2024120794 A1 WO 2024120794A1
Authority
WO
WIPO (PCT)
Prior art keywords
circular arc
semifinished product
mirror element
mirror
axis
Prior art date
Application number
PCT/EP2023/082131
Other languages
English (en)
Inventor
Jonathan Pira
Original Assignee
FLABEG France S.A.S.
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 FLABEG France S.A.S. filed Critical FLABEG France S.A.S.
Publication of WO2024120794A1 publication Critical patent/WO2024120794A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/08—Mirrors
    • G02B5/10—Mirrors with curved faces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R1/00—Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
    • B60R1/02—Rear-view mirror arrangements
    • B60R1/08—Rear-view mirror arrangements involving special optical features, e.g. avoiding blind spots, e.g. convex mirrors; Side-by-side associations of rear-view and other mirrors
    • B60R1/081—Rear-view mirror arrangements involving special optical features, e.g. avoiding blind spots, e.g. convex mirrors; Side-by-side associations of rear-view and other mirrors avoiding blind spots, e.g. by using a side-by-side association of mirrors
    • B60R1/082—Rear-view mirror arrangements involving special optical features, e.g. avoiding blind spots, e.g. convex mirrors; Side-by-side associations of rear-view and other mirrors avoiding blind spots, e.g. by using a side-by-side association of mirrors using a single wide field mirror or an association of rigidly connected mirrors

Definitions

  • the invention relates to a semifinished product for the production of at least one mirror element. It also relates to a mirror element and a corresponding method of manufacturing or production. Background
  • the goal of the present invention is to increase the field of view of a reflective sur- face.
  • spherical exterior mirrors as well as aspherical mirrors.
  • CO 2 footprint With the general goal of reducing CO 2 footprint one strives for a compact and streamlined design.
  • exterior mirrors should become smaller than with the current spherical or as- pherical design.
  • An objective of the present invention is to provide a semifinished product for the production of at least one mirror element which is compact in size and yet has a large field of view.
  • the semifinished product and the final mirror element shall be easy to manufacture.
  • a corresponding mirror element shall be provided as well.
  • a method of production shall be given.
  • the objective is met by a semifinished product as speci- fied in claim 1.
  • a corresponding mirror element is specified in claim 10.
  • Claim 14 provides an alternative characterization of the same idea.
  • a corresponding method of producing a mirror element is specified in claim 17.
  • the invention provides a semifinished product for the production of at least one mirror element, the semifinished product comprising a body or a substrate with a surface which forms a surface of revolution or a portion thereof, the surface of revolution being generated by revolving a generating plane curve around an axis of rotation, the generating plane curve comprising a first cir- cular arc with a constant first radius and a second circular arc with a second ra- dius, wherein the second circular arc continuously joins the first circular arc, and wherein the second radius is either constant or varies periodically during rotation around the axis of rotation, such that the surface of revolution has either discrete or continuous rotational symmetry with respect to the axis of rotation.
  • the second circular arc joins the first circular arc with continuous gradi- ent.
  • the generating plane curve comprises a non-circular arc which continuously joins the second circular arc.
  • the non-circular arc joins the second circular arc with continuous gradient.
  • the contour of the non-circular arc can be described by a cubic equation or a cubic polynomial.
  • the non-circular arc may be replaced by a fur- ther circular arc with constant radius.
  • the surface of revolution is a spheroid with a spherical cap, a spherical zone which joins the spherical cap and may have a varying ra- dius, and, if applicable, an aspherical zone which joins the spherical zone.
  • the surface of revolution may be a toroid with analog parts.
  • the invention also provides a mirror element which is a part cut from a semifin- ished product according to the above specification or has the same shape as such a part, such that a designated reflective surface comprises at least a section of the spherical zone, and, if present, at least a section of the aspherical zone, or such that an equivalent toroidal structure is established.
  • the semifinished product i.e., the calotte
  • the calotte is just a mathematical or mental object or definition which defines the geometry or the shape of the mirror surface of interest.
  • the claimed mirror element may be obtained (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx)
  • the calotte is not required to exist as a real object.
  • the alternative in claim 10, “or has the same shape as such a part”, is preferably interpreted: This is meant to cover a mirror el- ement obtained by single piece bending (or any other method of production) with a mirror surface having the shape as defined with respect to the calotte.
  • the mirror element may also comprise at least a section of the spherical cap, but for other cases the spherical cap is kept out from the mirror.
  • the interest of this spherical cap then is mainly to create the spherical zone with the expected design.
  • “cut” may be understood in either a literal sense of using a cutting tool for cutting individual mirror elements from the semifinished product, or in a broad abstract sense in that the surface of revolution is merely a geometry-defin- ing surface, and other methods of production may be used.
  • the spherical zone (or the toroidal counterpart) is intended as a part facing to a vehicle, and, if present, the aspherical zone is intended as a part facing away from a vehicle when used as automotive exterior rear view mirror.
  • the reflective surface is either a surface of the substrate or a coating or a layer or a structure on the substrate.
  • the shape of the mirror element can be obtained from or on a trans- parent substrate or a reflective substrate with all kinds of coatings in first surface or second surface, for example Chrome coating on first/front surface, Chrome coating on second/back surface, combination of Chrome and Titanium on first or second surface (e.g.
  • the shape can be used for a standard mirror, EC-glass with double glass, clear glass, clear glass with coated rim or coated area(s), or clear glass with a (reflective) foil, mirror combined with a spotter glass, or mirror with all kinds of la- sering application (i.e., demarcation line, lettering, symbol, blind spot detection, etc.) and/or edge finishing.
  • the designated reflective surface when viewed in direction of in- cident light, is a convex surface.
  • An alternative characterization of the mirror element is as follows: A mirror element with ⁇ a surface, ⁇ only one symmetry axis, ⁇ a curve revolving around the symmetry axis, defining a rotationally sym- metric part of the mirror surface with two successive spherical portions with different radii.
  • the first radius may be defined outside the mirror surface. That means that the proposed solution also works even if the first radius is not part of the mirror ele- ment (but this radius is in general still mandatory in the semifinished product defi- nition).
  • the mirror element may be used in an automotive exterior rear view mirror. However, other applications may be possible as well.
  • the mirror element is cut from a semifinished product according to the above description, wherein preferably a plurality of identical or similar mirror elements is cut from one workpiece.
  • Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx)
  • the geometry of the semi- finished product is merely used to define the geometry of a reflective surface of the respective mirror element.
  • Other methods of manufacturing for example bending, or additive manufacturing
  • FIG.1 to 5 illustrate geometric relationships and definitions for understanding the invention.
  • FIG.6 illustrates the concepts of bilateral, radial, and circular symmetry.
  • FIG.7 is a cross section through a spheroid calotte which may be a starting point for manufacturing a plurality of mirror elements.
  • FIG.8 is a top view on said calotte with a plurality of mirror elements indicated.
  • FIG.9 is a top view on a toroid calotte which may be an alternative starting point for manufacturing a plurality of mirror elements.
  • FIG.10 illustrates bilateral symmetry in a round calotte.
  • FIG.11 illustrates the definition of a breakpoint “a” for an aspherical portion of a mirror. (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx) Pav Speicherung: 16.
  • a plane curve is a curve in a two-dimensional plane, in contrast to a three- or more dimensional space curve.
  • a surface of revolution is a surface in Euclidean space created by rotating a plane curve (the generatrix or generating curve) around an axis of rotation (see FIG.1).
  • a spherical cap or spherical dome is a portion of a sphere cut off by a plane.
  • a spherical cap is the region of a sphere which lies above (or below) a given sectional plane (see FIG.2).
  • a spherical segment is the solid defined by cutting a sphere with a pair of parallel planes. It can be thought of as a spherical cap with the top truncated, and so it cor- responds to a spherical frustum.
  • the surface of the spherical segment (excluding the bases) is called a spherical zone (see FIG.3).
  • spherical zone is also used for a generalized case in which the radius associated with it varies during a revolution around the axis of ro- tation, yielding some kind of wavy or wobbly ring or band around the sphere.
  • a torus is a surface of revolution generated by revolving a circle in three-dimensional space about an axis that is coplanar with the circle (see FIG.4).
  • a toroid is a surface of revolution with a hole in the middle. The axis of revolution passes through the hole and so does not intersect the surface. For example, when (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx) Chip Speicherung: 16.
  • TERGAU & WALKENHORST Page 8 a rectangle is rotated around an axis parallel to one of its edges, then a hollow rec- tangle-section ring is produced (see FIG.5). If the revolved figure is a circle, then the object is called a torus.
  • a spheroid is meant to be an approximately spherical body which preferably comprises at least one spherical portion, in particular a spherical cap. It can be obtained as a surface of revolution which intersects the axis of revo- lution.
  • FIG.6 illustrates the concepts of bilateral (left), radial (middle), and circular (right) symmetry.
  • a bilateral symmetry is a symmetry in which similar parts are arranged on opposite sides of a median axis so that only one plane can divide the workpiece into essen- tially identical halves.
  • a radial symmetry is a symmetry in which similar parts are regularly arranged around a central axis.
  • a circular symmetry is a continuous symmetry in which a planar object can be ro- tated by any arbitrary angle and map onto itself.
  • rotational symmetry also known as radial symmetry in geometry, is the property a shape has when it looks the same after some rotation by a partial turn.
  • An object's degree of rotational symmetry is the number of distinct orienta- tions in which it looks exactly the same for each rotation. (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx) Pav Speicherung: 16.
  • FIG.7 illustrates a first embodiment of the present invention.
  • a plane curve in a Cartesian (e, z) reference frame comprises three sections or parts.
  • a first part comprises a first circular arc 2 with radius R1 which intersects the z axis in the co- ordinate origin (0, 0). The center of said first circular arc 2 has the coordinates (0, - R 1 ).
  • Said sec- ond circular arc 4 has a center with coordinates (e2, z2).
  • a surface of rev- olution is established which may be called a calotte 8 and which envelops a sphe- roid.
  • a top view on the calotte 8 is shown in FIG.8.
  • the calotte 8 has a circular symmetry (or a cylindrical symmetry when viewed as a 3D object). (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx) Pav Speicherung: 16.
  • the third circular arc 6 may be replaced by a non-circular arc, leading to an outer aspherical zone 14 in the calotte (see FIG.8).
  • the spherical zone 12 joining the spherical cap 10 may have a ra- dius which oscillates periodically between a first limiting value R2 (e.g., maximum) and a second limiting value R’2 (e.g., minimum) when revolving around the axis of rotation (z-axis), yielding some kind of wavy or wobbly ring or band around the spheroid.
  • R2 e.g., maximum
  • R’2 e.g., minimum
  • the radius may follow a sine or cosine pattern over angle ⁇ . While the resulting calotte 8 no longer has a circular symmetry, the periodic na- ture of these oscillations establishes a discrete rotational symmetry.
  • each mirror element 16 comprises a portion of the spherical cap 10, a portion of the adjacent spherical zone 12, and, if present, a portion of the outer aspherical zone 14 (which in the limiting case may be another spherical zone).
  • each mirror ele- ment 16 is centered around a dedicated radial beam 18 which corresponds to a multiple of the elementary angel of rotation ⁇ which does not change the object (rotational invariance).
  • the indicated mirror elements 16 belong to right-hand au- tomotive exterior rear view mirrors, wherein the spherical cap portion is intended as a part facing to a vehicle, and the aspherical zone portion is intended as a part facing away from a vehicle.
  • the corresponding left-hand mirrors can be obtained by axis mirroring.
  • the calotte 8 may represent the surface of a substrate or body from which the mirror elements 16 are cut. That is, the calotte 8 is a semifinished prod- uct 22 from which the mirror elements 16 are cut.
  • the substrate can either be re- flective itself or be provided with a reflective surface.
  • the surface of the calotte 8 is merely a geometry-defining surface, and other methods of manufacturing (for example bending, or additive manufacturing) may be used to produce mirror elements 16 whose reflective surfaces have a corre- sponding shape.
  • FIG.9 represents a top view of such a toroidal calotte with mirror positions indicated.
  • the calotte can be designed with a CAD software, considering freeform curves in both directions, or a freeform curve and a constant radius, or a succession of radii in both directions, with an optional aspherical portion in x-direction or y-direction.
  • b) Anamorphic Design Another option is to design this kind of calotte with anamorphic mathematical for- mulas, considering a different radius Rx1 in x-direction, and Ry1 in y-direction.
  • ⁇ Without an aspherical portion Where ⁇ ⁇ , ⁇ may be a polynomial function.
  • Multi yield calotte with a radial or circular symmetry A further development is to apply different freeform curves on a calotte WITH a ra- dial symmetry. But preferred would be to restrict the freeform curves to a successive- sion of constant radii with an optional aspherical portion WITH a radial symmetry. More preferred would be to restrict the freeform curves to one freeform curve WITH a circular symmetry. Even more preferred would be to restrict the freeform curve to a succession of constant radii with an optional aspherical portion WITH a circular symmetry. In the following calculations, we will work with the polar coordinates: a) Calotte with a radial symmetry A succession of constant radii is preferred with a continuity of the tangent all along the curve.
  • FIG.7 and 8 provide an example with three successive radii R1, R2 and R3, where the variable “a” is used to define the breakpoint between the two radii R 1 and R 2 , and the variable “b” is used to define the breakpoint between the two radii R 2 and R3.
  • the freeform curves can be defined function of the angle ⁇ . As an example, we could define a freeform curve going through the middle of a mirror and another one between two mirrors.
  • the coefficients k1 and k2 are used in the aspherical portion for the two limit freeform curves.
  • ⁇ 0 rad: (Z: ⁇ DOCUMENT ⁇ AMT ⁇ 2117897.docx)
  • ⁇ ⁇ /8 rad:
  • the freeform curve is defined for any ⁇ and any quantity of shapes called “NbShapes”: With ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ h ⁇ ⁇ ⁇ ⁇ ⁇ being a function of ⁇ and ⁇ ⁇ ⁇ h ⁇ ⁇ ⁇ ⁇ .

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Multimedia (AREA)
  • Mechanical Engineering (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

Un objectif de la présente invention est de fournir un produit semi-fini (22) pour la production d'au moins un élément de miroir (16) qui est compact en taille et qui présente cependant un grand champ de vision. Le produit semi-fini (22) et l'élément de miroir final (16) sont faciles à fabriquer. À cette fin, l'invention propose un produit semi-fini (22) pour la production d'au moins un élément de miroir (16), le produit semi-fini (16) comprenant un corps ou un substrat avec une surface qui forme une surface de révolution (24) ou une partie de celui-ci, la surface de révolution (24) étant générée en tournant une courbe de plan de génération autour d'un axe de rotation (z), la courbe de plan de génération comprenant un premier arc circulaire (2) ayant un premier rayon constant et un second arc circulaire (4) ayant un second rayon, le second arc circulaire (4) joignant en continu le premier arc circulaire (2), et le second rayon étant soit constant, soit variant périodiquement pendant la rotation autour de l'axe de rotation (z), de telle sorte que la surface de révolution (24) a une symétrie de rotation discrète ou continue par rapport à l'axe de rotation (z).
PCT/EP2023/082131 2022-12-06 2023-11-16 Élément de miroir et procédé de production correspondant WO2024120794A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102022132407.9 2022-12-06
DE102022132407.9A DE102022132407A1 (de) 2022-12-06 2022-12-06 Spiegelelement und entsprechendes Herstellungsverfahren

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WO2024120794A1 true WO2024120794A1 (fr) 2024-06-13

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Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1279158A (en) * 1968-06-27 1972-06-28 Kurt Hacker Driving-mirror assembly for a vehicle
EP0236708A2 (fr) 1986-02-12 1987-09-16 INNOVATEC RECHERCHE & DEVELOPPEMENT, INC. Béquille et canne téléscopique
EP0435793A2 (fr) * 1989-12-22 1991-07-03 René Burgat Rétroviseur notamment pour véhicules automobile
DE19739046C2 (de) 1997-09-05 2001-10-25 Schott Desag Ag Farbneutraler Rückblickspiegel, insbesondere für Fahrzeugspiegel
DE102007060374A1 (de) 2007-12-12 2009-06-25 Flabeg Gmbh & Co. Kg Halbdurchlässiger Spiegel
EP1688302B1 (fr) 2005-02-02 2010-07-14 Flabeg GmbH & Co. KG Rétroviseur pour véhicules
US8180606B2 (en) 2007-02-01 2012-05-15 Drexel University Wide angle substantially non-distorting mirror
EP1751588B1 (fr) 2004-05-12 2013-09-25 FLABEG Deutschland GmbH Retroviseur anti-eblouissement pour vehicules
DE112005000782B4 (de) 2004-05-12 2014-12-31 Flabeg Deutschland Gmbh Rückblickspiegel für Fahrzeuge

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1279158A (en) * 1968-06-27 1972-06-28 Kurt Hacker Driving-mirror assembly for a vehicle
EP0236708A2 (fr) 1986-02-12 1987-09-16 INNOVATEC RECHERCHE & DEVELOPPEMENT, INC. Béquille et canne téléscopique
EP0435793A2 (fr) * 1989-12-22 1991-07-03 René Burgat Rétroviseur notamment pour véhicules automobile
DE19739046C2 (de) 1997-09-05 2001-10-25 Schott Desag Ag Farbneutraler Rückblickspiegel, insbesondere für Fahrzeugspiegel
EP1751588B1 (fr) 2004-05-12 2013-09-25 FLABEG Deutschland GmbH Retroviseur anti-eblouissement pour vehicules
DE112005000782B4 (de) 2004-05-12 2014-12-31 Flabeg Deutschland Gmbh Rückblickspiegel für Fahrzeuge
EP1688302B1 (fr) 2005-02-02 2010-07-14 Flabeg GmbH & Co. KG Rétroviseur pour véhicules
EP2279909A2 (fr) 2005-02-02 2011-02-02 Flabeg GmbH & Co. KG Rétroviseur pour véhicules
US8180606B2 (en) 2007-02-01 2012-05-15 Drexel University Wide angle substantially non-distorting mirror
DE102007060374A1 (de) 2007-12-12 2009-06-25 Flabeg Gmbh & Co. Kg Halbdurchlässiger Spiegel

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DE102022132407A1 (de) 2024-06-06

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