Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/10—Filters, e.g. for facilitating adaptation of the eyes to the dark; Sunglasses
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/12—Polarisers
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C2202/00—Generic optical aspects applicable to one or more of the subgroups of G02C7/00
  • G02C2202/16—Laminated or compound lenses

Definitions

• the present invention relates to non-correcting eyepiece blanks, making it possible to obtain non-correcting eyepieces by trimming, and whose shape and dimensions are suitable for mounting in or on a suitable frame of a pair of glasses.
• the invention also relates to pairs of glasses, intended for solar or industrial protection, comprising two non-correcting eyepieces, each capable of being obtained by trimming a blank as defined above, these eyepieces being mounted or supported in or by an appropriate frame.
• the invention is concerned with blanks of non-correcting ocular polarizing or having another optical function and glasses obtained from such blanks, and consequently comprising two non-correcting eyepieces also polarizing or having this other function.
• the latter is for example the photochromic function which modifies the intensity of the tint of the glass as a function of the light intensity received.
• a composite sheet comprising a filtering film of a polarizing material, inserted between two layers of a transparent material, transmitting light, preferably d 'a thermoplastic material, for example a polycarbonate.
• a thermoplastic material for example a polycarbonate.
• this composite sheet is then cut flat a blade, delimited by a peripheral border. Then this blade is thermoformed, to obtain a blank, according to any predetermined radius of curvature, and delimited between a convex outer face and an opposite, inner and concave face.
• the blank From the preferential plane of polarization of the filter film, and taking into account the angular orientation of said film with respect to the two layers of the transparent material, the blank acquires a preferential plane of polarization.
• the latter preferably remains substantially parallel to the optical axis of the eyepiece which will then be obtained by trimming said blank.
• the blanks and eyepieces obtained from thermoformed composite sheets have optical characteristics poor, even insufficient, in particular for significant curvatures (base 6 and beyond). Indeed, the power and prism values of the eyepiece obtained by trimming such a blank do not comply with the standards in force. This results in particular from the fact that the thermoforming operation does not make it possible to control the relative position of the anterior and posterior diopters, and therefore the position of the optical center of the blank.
• a non-correcting eyepiece blank having good optical characteristics, in particular of power and of prism, including glasses of strong curvature, corresponding to a radius. mean of curvature at most equal to about 90 mm.
• This blank comprises a transparent blade, having on the one hand, a geometric axis, passing through said blade and defining a geometric center, and on the other hand, an optical axis defining an optical center.
• the blade seen in elevation, also has a generally non-circular periphery, and the optical axis and the geometric axis, and consequently the optical and geometric centers, are distinct and offset angularly and by a predetermined distance l of each other.
• the present invention relates to a non-corrective eyepiece blank incorporating any optical function such as for example polarization, making it possible to obtain substantially the same optical characteristics as those obtained in accordance with document FR 2 740 231, notwithstanding the presence in the draft of a film allowing it to integrate a function such as polarization, infrared filtration or any other known function which can be applied to an eyepiece.
• any optical function such as for example polarization
• the blank comprises a composite blade, delimited by a peripheral border and between a convex outer face and an opposite, inner and concave face, said composite blade being made up of at least one transparent material, transmitting light from the outside face to the inside face, and said composite strip incorporating a film integrating the optical function.
• This composite blade has, in a first embodiment according to the invention, the following structure and arrangement: - the blade firstly comprises a matrix of the transparent material, determining on the inner side the inner face of the eyepiece; and in this matrix is reserved on the outside for a convex housing, the flat surface of which occupies most of the surface of the composite blade; and
• This composite blade has, in a second embodiment according to the invention, the following structure and arrangement:
• the blade first comprises a matrix of transparent material, determining on the outside the outside face of the eyepiece; and in this matrix is reserved on the interior side a concave housing whose flat surface occupies most of the surface of the composite blade; and
• a blank obtained in accordance with the invention makes it possible to control, in particular in terms of tolerance and positioning, the correct orientation of this blank during its trimming and consequently the quality of the eyepiece thus obtained.
• the housing is for example a convex housing disposed on the outer face of the matrix. Thanks to the arrangement of the film on the outside of the blank, the outside of the film essentially corresponds to the convex outside of the blank or then of the eyepiece. In addition, the stresses generated in the injected transparent material, which normally generate a parasitic polarization, are almost imperceptible to the eye of the user of the glasses.
• the film piece advantageously has a constant thickness.
• the peripheral border has two concentric circular truncated edges, separated by two parallel straight edges, for example of identical lengths, and the periphery of the housing has substantially the same profile as that of the peripheral border, and fits homothetically in the latter.
• the peripheral edge is at least for the most part circular, and the periphery of the housing comprises two concentric circular truncated edges, separated by two parallel straight edges, for example identical lengths.
• the peripheral border comprises for example a majority circular part and a straight part, which is confused with a straight edge of the housing.
• the inner and outer faces each have, at least in part, a symmetry of revolution about a same axis, called the optical axis, determining where appropriate an optical center on the two outer and inner faces of the composite blade.
• the peripheral border has for example at least partly a profile of revolution around a geometric center, arranged at a distance and distinct from the optical axis.
• the outer face of the composite strip is advantageously coated with at least one layer of a material chosen from the group comprising anti-scratch materials, filtering materials, colored materials.
• the film integrating the optical function can be a filter film of a polarizing material and the angular orientation of the part of the filter film in and relative to the matrix of the transparent material, around a normal axis passing through them, is then preferably chosen to give the blank a preferential plane of polarization, substantially parallel to a transverse plane intersecting it.
• the preferential plane of polarization of the eyepiece is chosen to present any predetermined angular orientation (substantially perpendicular, parallel or other), by reference to a mark or marks, normally present on the blank, taking into account in particular of the interface existing between polarizing and transparent materials, or by reference to a reference or reference marks reported on the blank, for example intaglio or relief markings, making it possible to define at the time of trimming one or more reference axes .
• substantially parallel or perpendicular one takes into account the consideration according to which the curvature of the blank, and subsequently of the eyepiece, considered in a vertical or horizontal insertion plane (relative to the eyepiece in position on the user's head, through the glasses), changes the orientation of the plane of polarization, going from the edge towards the center of the blank or the eyepiece.
• a blank with a piece of polarizing filter film, obtained in accordance with the invention makes it possible to control, in particular in terms of tolerance, the angular positioning of the preferential plane of polarization of the blank, and then of the eyepiece obtained by trimming of this draft.
• the peripheral border comprises two truncated concentric circular edges, separated by two parallel straight edges, for example of identical lengths
• the periphery of the convex housing has substantially the same profile as that of the peripheral border, and fits homothetically in the latter and when the piece of film is a piece of polarizing filter film
• the piece of filter film is advantageously cut from the polarizing film, so that the preferential plane of polarization is substantially parallel or perpendicular to each parallel straight edge of said part, whereby each parallel straight edge of the blank is substantially parallel or perpendicular to the preferential plane of polarization of the latter.
• the periphery of the convex housing comprises two concentric circular truncated edges, separated by two parallel straight edges, by example of identical lengths and when the piece of film is a piece of polarizing filter film, then the piece of filter film is advantageously cut in the form of a strip in the polarizing film, so that the preferred plane of polarization is substantially parallel or perpendicular to each parallel straight edge of said piece, whereby at least one straight line of separation between the matrix of transparent material and the piece of filter material is substantially parallel or perpendicular to the preferential plane of polarization of the blank.
• the axis optic is for example substantially parallel or perpendicular to the plane of polarization preferential of said blank in the case of polarizing glasses.
• the geometric shape of the outer face and / or of the inner face of the composite blade can also be determined so that in a section plane, substantially parallel or perpendicular to the preferred plane of polarization, the thickness of the composite blade continuously decreases away from the optical axis outwards.
• the geometric shape of the outer face and the geometric shape of the inner face correspond, for example, respectively to two spheres of centers spaced apart along the optical axis.
• the peripheral border has for example at least partly a profile of revolution around a geometric center, arranged at a distance and distinct from the optical axis, the optical axis and the geometric center advantageously determine a plane substantially parallel or perpendicular to the preferential plane of polarization of said blank in the case of polarizing lenses.
• the invention also relates to a pair of glasses comprising a frame and two non-correcting eyepieces integrating an optical function such as polarization, supported by said frame, each eyepiece comprising a composite blade delimited between a convex outer face and an opposite, inner face. and concave, said composite blade consisting of at least one transparent material, transmitting light from the outside face to the inside face, and said composite blade incorporating a film integrating the optical function.
• an optical function such as polarization
• each eyepiece comprises, from the inside towards the outside, or vice versa, a first thickness of the transparent material, determining on the inside side, respectively outside, said inside face, respectively outside, and, directly in contact with the first thickness, a second thickness of the film, determining the exterior side, respectively interior, said exterior face, respectively interior, of the eyepiece.
• each eyepiece of the pair of glasses is a polarizing eyepiece
• each eyepiece is for example oriented angularly with respect to the frame, about a normal axis passing through it, so that its preferred plane of polarization is substantially parallel or perpendicular with the horizontal plane of the pair of glasses, passing through the axis of vision of the glasses in position on the head of the user.
• the transparent material of a blank according to the invention can be obtained for example by injection.
• the invention then also relates to a mold for injecting the transparent material, consisting of a thermoplastic or thermosetting synthetic material, to obtain a blank as described above, said mold comprising two complementary and removable parts, one with respect to the 'other, determining once assembled one on the other an air gap whose volume and shape determine those of the blade; the part of the mold determining the external face of the blade comprises means for positioning the convex part of the film.
• a mold will be used in particular for polarizing blanks.
• a blank according to the invention can also be obtained by a production method comprising a step of overmolding the part of the film by extrusion.
• the parts obtained after extrusion can be cut and thermoformed.
• Another production method provides that the matrix made of transparent material and the part integrating the function is produced separately and that a bonding of these two elements is subsequently carried out. All these solutions make it possible to obtain good optical quality, respecting Gullstrand's law.
• Figures 1 and 2 show a blank according to the present invention, respectively viewed from the outside, and from the inside where the eye of the user of the pair of glasses is next, incorporating an eyepiece obtained by trimming the blank according to Figures 1 and 2;
• FIG. 3 shows a cross-sectional view of the blank according to Figures 1 and 2, the section plane being horizontal relative to the normal position of the above pair of glasses on the head of the user, and passing through the optical center of the blank;
• FIG. 5 shows a pair of glasses comprising two eyepieces each obtained by trimming a blank according to Figures 1 to 4;
• FIG. 6 shows a partial view in cross section, along a horizontal plane as defined above, of the part of the glasses shown in Figure 5, corresponding to the left eyepiece;
• FIG. 7 shows, in cross section, an injection mold of a transparent, thermoplastic material, for example polycarbonate, to obtain a blank according to the representation of Figures 1 to 4;
• Figure 8 shows, front view, a part of the mold shown in Figure 7;
• this blank 1 comprises a composite blade 2, having a curved or curved shape.
• This blade is delimited by a peripheral edge 2a, and between an outer face 2b convex and an opposite face 2c, inner and concave.
• this composite blade 2 is made of a transparent material, for example polycarbonate, transmitting light from the outer face 2b to the inner face 2c of the blade.
• This blade also incorporates a filter film 6 of a polarizing material, which gives the blank a plane 3 of preferential polarization.
• the composite blade 2 comprises a matrix 4 of the transparent material, determining entirely on the interior side the interior face 2c of the blank, and in which is reserved, on the exterior side, a housing 5 of convex shape, the flat surface of which occupies most, if not almost all, of the surface of the composite strip 2.
• a piece 6 of a filter film of a thermoplastic polarizing material is adapted by flat cutting, then by thermoforming, to the convex shape and to the dimensions of the convex housing 5.
• the convexity of the housing 5 is identical to that of the outer face 2c of the matrix 4.
• the positioning of the part 6 relative to the matrix 4 is obtained by any appropriate means, for example by simple interlocking or assembly, or with recessed or raised marks.
• the part 6 of the filter film has a constant thickness, as shown in particular in FIGS. 3 and 4, while the matrix 4 has a thickness which decreases from the optical axis towards the outside (FIG. 4).
• the peripheral edge 2a of the blank 1 has two edges 2a1 and 2a2, circular and concentric around a geometric center or barycenter 10, truncated, and separated by two edges 2a3 and 2a4, straight and parallel, for example of identical lengths.
• the periphery 5a of the flat housing 5 has substantially the same profile as that of the peripheral edge 2a of the blade 2, and fits homothetically in the latter.
• the part 6 of the filter film is cut and thermoformed therein, so that the preferential plane of polarization of said film is substantially parallel or perpendicular to each parallel straight edge 5a3 or 5a4 of this part, whereby each parallel straight edge 2a3 or 2a4 of the blank is itself substantially parallel or perpendicular to the plane 3 of preferential polarization of the latter (cf. in particular FIG. 2).
• the inner 2b and outer 2c faces of the composite blade 2 each have at least in part a symmetry of revolution about the same axis 7, identical to the optical axis of the blank 1, determining an optical center 8 on the outer 2b and inner 2c faces of the blade 2.
• the optical axis 7 does not necessarily cross the blank 1, and may be outside of the latter. As shown in FIG. 2, the optical axis 7 is substantially parallel to the plane 3 of preferential polarization of the blank 1. Still in a manner known from document FR 2 740 231, the geometric shape of the outer face 2b and / or of the inner face 2c of the composite strip 2, are determined so that in a horizontal section plane, as defined with reference to FIG. 3, itself substantially parallel to the plane 3 of preferential polarization, the thickness of the composite strip 2 decreases continuously in moving away from the optical axis 7, that is to say going from the optical axis for example towards the left outer side of the temple of the wearer of the glasses.
• the geometric shape of the outer face 2b and the geometric shape of the inner face 2c are respectively inscribed in two spheres of spaced centers, the respective centers 81 and 9 of which are both located and offset relative to each other, on the optical axis 7.
• the radii R1 of the sphere corresponding to the outer face 2b, and R2 of the sphere corresponding to the inner face 2c, are different.
• the preferential plane of polarization is in fact slightly secant or inclined (from 0 ° to 30 °), relative to the plane determined by the optical axis 7 and the geometric center 10.
• the peripheral edge 2a of the eyepiece 1 is circular, and the periphery 5a of the housing 5 of the part 6 of the filter film comprises two concentric circular edges 5a 1 and 5a2 truncated, separated by two parallel straight edges 5a3 and 5a4, for example of identical lengths.
• the part 6 of the filter film is cut in the form of a strip in the polarizing film, so that the plane 3 of preferential polarization is substantially parallel or perpendicular to each straight edge of said part, whereby each straight line of separation between the matrix 4 of the transparent material and the part 6 of the filtering and colored material is substantially parallel or perpendicular to the plane of polarization preferential 3 of the draft.
• the blank shown in Figure 10 differs from that shown in Figure 9, in that the peripheral edge 2a has a majority circular portion and a straight portion 2a5, which coincides with a straight edge 5a4 of the housing 5 convex.
• the preferential polarization plane 3 can be substantially, or parallel or perpendicular to the visual reference frame chosen and determined on the blank, for example the parallel straight edges 5a3 and 5a4 according to FIG. 9.
• each eyepiece 13 or 14 then comprises a composite blade 15 delimited between an outer face 15a convex and an opposite face 15b, inner and concave.
• This composite strip 15 is made up of at least one transparent material 16, transmitting light from the outside face 15a to the inside face 15b. And this composite plate 15 incorporates a film 17 filtering polarizing material, determining for each eyepiece at least one plane 3 of preferential polarization (cf. FIG. 5).
• Each eyepiece 13 or 14 comprises, from the inside to the outside, on the one hand a first thickness of the transparent material 16, determining on the inside the internal face 15b, and on the other hand, directly in contact with the first thickness , a second thickness of the filter film 17, determining on the outside said outside face 15a of the eyepiece.
• each eyepiece 13 or 14 is oriented angularly with respect to the frame 12, around its optical axis 7 for example, so that its plane 3 of preferential polarization is substantially parallel or coincident with the horizontal plane of the pair glasses, passing through the axis of vision 18 of the glasses in position on the head of the user.
• axis of vision is meant an axis extending in a horizontal plane passing through the two pupils of the user, in front of the head of the latter, and practically without horizontal and / or vertical deviation, starting from '' a point located in the center of the inter-pupillary distance.
• each eyepiece 13 or 14 is substantially or parallel or perpendicular to the reference frame chosen and predetermined on the pair of glasses 1 1, for example the horizontal passing plane by the axis of vision 18.
• This mold comprises two removable and complementary parts 20 and 21 relative to one another, determining once assembled one on the other, an air gap 22 whose volume and shape determine those of the blade 2.
• the concave part of the mold 21 determining the outer face 2b of the blank 1 comprises positioning means or pins 23a to 23c, flat, of the convex piece 6 of the filter film.
• the part 6 can be cut flat, and not thermoformed. It is then placed and positioned as previously in the concave part 21 of the mold, temporarily matching its shape. It will take a definitively convex shape at the time of the injection of the transparent material, polycarbonate for example.
• the part 6 of the filter film is cut flat and then thermoformed, so as to have in its curved conformation the shape and the dimensions described with reference to FIGS. 1 to 4. Then this part is placed in the air gap 22 of the mold to serve as an insert, being positioned using the pins 23a to 23c, to define, after injection of the transparent material into the air gap 22, a predetermined orientation of the part 6 relative to the rest of the blade 2, giving the 'blank 1 a preferential plane of polarization, itself in a determined angular position relative to the latter.
• the present invention it is possible to cut out each geometrically precise blank relative to its preferential plane of polarization, from which it follows that the eyepiece thus obtained can in turn be geometrically precise mounted on the frame of the glasses, which in total makes it possible to position the planes preferential polarization of the two eyepieces respectively, geometrically precise with respect to the glasses, and in particular with a small angular difference between the preferential polarization planes of the two eyepieces respectively.
• the present invention also relates to other functions, for example infrared filtration, which are difficult to access by injection.
• the known pigments which have infrared filtration properties are sensitive to heat and degrade when they are subjected to the injection temperatures required by the use of the injected polycarbonate (280 to 340 ° C).
• the use of these pigments in extruded polycarbonate makes it possible to form a sheet integrating these pigments without reaching the limit temperatures of use which are approximately 200 to 250 ° C.
• This sheet can then be thermoformed to obtain the shape of the glass. . During this thermoforming, the temperature in the sheet does not exceed 200 ° C.
• the thermoformed sheet can then be overmolded.
• the method according to the invention also makes it possible to create an optical function in the region of the glass where it is useful.
• the photochromic function which modifies the intensity of the tint of the glass in depending on the light intensity received can be obtained by incorporating photochromic pigments into the injected material.
• These pigments are sensitive to heat and lose much of their effectiveness when injected at the temperature of polycarbonate.
• the quantity of pigments necessary to properly perform this function is so large that it influences (negatively) significantly the mechanical resistance properties of the finished product to such an extent that there is no longer any point in choosing the polycarbonate as base material.
• the effective proportion of pigments is very low since only the pigments present on the external surface of the part are activated. The overmolding process is then entirely suitable for this photochromic function.
• Still other functions can be obtained by the method according to the invention: obtaining a coloration, a hard surface layer, special filtration (laser, infrared, gradient, etc.), obtaining an anti-fog layer ....
• the housing intended to receive the composite blade integrating this function can be produced on the convex face, as described above, or on the concave face of the blank.
• Obtaining a blank according to the invention can also be produced by another method than the overmolding method described by way of nonlimiting example above.
• a blank according to the invention can also be obtained by gluing, by bi-injection or by any other method.
• the molding process described above, or alternatively bonding allow the use of substantially different materials at the level of the composite blade and the matrix. These methods make it possible for example to use acetobutyrate cellulose (CAB) which is advantageous to implement with regard to the stresses linked to heat.
• CAB acetobutyrate cellulose

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• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Polarising Elements (AREA)
• Eyeglasses (AREA)
• Microscoopes, Condenser (AREA)

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• 1998
  • 1998-12-03 FR FR9815453A patent/FR2786885B1/fr not_active Expired - Fee Related
• 1999
  • 1999-12-03 EP EP99957363A patent/EP1135711A1/de not_active Ceased
  • 1999-12-03 AU AU15091/00A patent/AU1509100A/en not_active Abandoned
  • 1999-12-03 WO PCT/FR1999/003011 patent/WO2000033123A1/fr not_active Ceased
  • 1999-12-03 US US09/856,960 patent/US6554421B1/en not_active Expired - Fee Related

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