Laser Cutting of Laminated Liquid Crystal Films for Use in Lenses for Training Eyewear
20220004033 · 2022-01-06
Assignee
Inventors
Cpc classification
B23K26/083
PERFORMING OPERATIONS; TRANSPORTING
G02F1/16753
PHYSICS
B23K2103/42
PERFORMING OPERATIONS; TRANSPORTING
B23K26/0869
PERFORMING OPERATIONS; TRANSPORTING
B23K26/03
PERFORMING OPERATIONS; TRANSPORTING
B23K26/0626
PERFORMING OPERATIONS; TRANSPORTING
B23K26/402
PERFORMING OPERATIONS; TRANSPORTING
International classification
G02F1/13
PHYSICS
B23K26/06
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Laminated liquid crystal films may be processed using a laser beam to form tear lines. Tear lines create a weak line in a liquid crystal film along which a portion of a PET layer may be torn from the whole PET layer. Tear lines are made by the precise volumetric removal of PET material from a portion of a PET layer by burning away the PET material using the laser beam. The form, extent and depth of penetration of a laser beam into a PET layer may be precisely controlled by adjusting the power and/or scan speed of the laser beam relative to the laminated liquid crystal film on which the PET layer is positioned. In this manner, a desired volume of PET material may be removed from the PET layer.
Claims
1. An apparatus for the controlled and precise volumetric removal of a plastic material from a laminated liquid crystal film to create a tear line in the plastic material comprising: a laser suitable to produce a beam of coherent light having a wavelength, intensity, diameter and cross-sectional shape suitable to remove a volume of a plastic layer incorporated as a surface material on a laminated liquid crystal film a controllable, moveable mount to control and move the laser during the removal of a volume of the plastic layer a controllable, moveable mount to control and move a laminated liquid crystal film to be cut a power controller to control the output power of the laser a motion controller to control the motion of the laser mount relative to the laminated liquid crystal film mount and sensors suitable to track the removal of a volume of the plastic layer of a laminated liquid crystal film to ensure the desired length, depth and shape of the volume of plastic layer is so removed from the plastic layer of the liquid crystal film.
2. The apparatus of claim 1 in which the motion of the laser is in one dimension.
3. The apparatus of claim 1 in which the motion of the laser is in two dimensions.
4. The apparatus of claim 1 in which the motion of the laser is in three dimensions.
5. The apparatus of claim 1 in which the motion of the laminated liquid crystal film mount is in one dimension.
6. The apparatus of claim 1 in which the motion of the laminated liquid crystal mount is in two dimensions.
7. The apparatus of claim 1 in which the motion of the laminated liquid crystal mount is in three dimensions.
8. A method for cutting a tear line in a PET layer of a laminated liquid crystal film using the steps of: on a laser source mounted on a controllable, moveable mount setting the power level, diameter of laser beam and shape of the laser beam, in a control device set the motion of the laser source and the scan speed of the motion of the laser source, placing a laminated liquid crystal film on a controllable, moveable mount, in a control device set the motion of the controllable, moveable mount for the laminated liquid crystal film, using the laser beam of the laser source to remove a volume of plastic from a plastic layer from the laminated liquid crystal film in which the volume of the plastic so removed is determined by the width, length and depth of the plastic so removed.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
[0026] Systems and methods in accordance with the present invention improve the processing of laminated liquid crystal films. Referring to
[0027] In order to apply the voltage differential needed to cause the transition of the liquid crystals in a liquid crystal film to transition between states, electrical connections must be made to the two electrical contact layers 140 and 150 disposed on the opposite sides of the liquid crystal layer 130. In laminated liquid crystal films, establishing those electrical connections can be challenging, especially when the laminated liquid crystal film must be cut to a desired shape or configuration. Materials such as PET are often used to enclose the liquid crystal and the electrical contact layers, as described above. The nature of PET presents challenges to forming a portion of a laminated liquid crystal film into a needed shape while likewise exposing the appropriate electrical contact layers at the positions needed to make electrical connections to control the liquid crystal film.
[0028] In accordance with the present invention, the selective removal of a portion of a PET layer is facilitated by at least partially penetrating the PET layer using a laser beam to remove, by evaporation or boiling off, a selected portion of the PET material so as to form a tear line. A tear line may extend at least partially through the PET layer and along some length of the PET layer, permitting the PET layer to be mechanically or manually separated along the tear line. Removal of the PET layer along the tear line exposes the underlying layers, such as an electrical contact layer or the liquid crystal layer. Given the delicacy of the electrical contact layer, removal of the PET layer along the tear line often removes the adjacent electrical contact layer adhered to the PET layer, thus exposing the liquid crystal layer. The liquid crystal layer so exposed by the removal of the PET layer at the tear line may thereafter be removed by using a solvent and/or a mechanical process in order to expose the opposing electrical contact layer underlying the liquid crystal layer. In some embodiments of the invention, this process may be repeated on both sides of a laminated liquid crystal film, thereby permitting electrical contact layers on each side of the liquid crystal layer to be exposed without damaging the electrical contact layer and permitting the electrical connections needed to operate the liquid crystal film to be made.
[0029] Referring still to
[0030] The dimensions of each layer above may vary from embodiment to embodiment depending on use. In certain uses, such as for vision training eyewear, the first PET layer 110 and the second PET layer 120 may each be approximately 200 microns think, with the liquid crystal layer 130 approximately 25 microns think. Further, each of the first electrical contact layer 140 and electrical contact layer 150 may be a few hundred nanometers thick, such as approximately 300 nanometers thick. The thicknesses of each of the layers depicted in
[0031] If applied to a polycarbonate layer, the polycarbonate layer may have an appropriate thickness (which need not be constant) for the desired physical and/or optical properties. In some embodiments, a polycarbonate layer may be approximately one to three millimeters thick.
[0032] Still referring to
[0033] Referring now to
[0034] As depicted in
[0035] Referring now to
[0036] While
[0037] Although the figures depict a macroscopic motion of laser source 410 relative to laminated liquid crystal film 400, beam deflection mechanisms, such as galvanometers or acousto-optical diffraction gratings or the like, with appropriate optics may be used to effect the scan of the laser beam 415 over the laminated liquid crystal film 400. Such beam deflectors may be preferable in some embodiments because of the resulting scan speed and precision and because of the reduced need for macroscopic motion systems.
[0038] The mechanisms by which either laser source 410 or laminated liquid crystal film 400 or both are moved are not depicted. A variety of controlled moveable mounts, jigs or other systems to enable motion of each is permitted in different embodiments of the invention so long as the described tear lines are made.
[0039] As depicted in
[0040] As depicted in
[0041] As depicted in
[0042] While depicted in examples with rectangular laminated liquid crystal films having first, second, third and fourth edges in the examples of
[0043] In some examples in accordance with the present invention, prior to forming tear lines as described in examples herein, a laser may be used to cut a piece of laminated liquid crystal film from a “raw” state after initial manufacture to a desired size and shape for processing into a final product. For example, a laser (which may be the same laser used to cut tear lines, but set at a different power and/or scan speed, or a different laser) may be used to cut a piece of shaped laminated liquid crystal film from a larger, raw piece of laminated liquid crystal film. This example might include cutting a lens shaped piece of laminated liquid crystal film slightly larger than the final lens size but in the shape of the desired piece to be used in eyewear. That piece of laminated liquid crystal film may be further processed as described herein to form tear lines that may be used to expose electrical contact layers as needed to operate the liquid crystal layer within the laminated liquid crystal film. If the same laser is used to cut a piece of laminated liquid crystal film in a desired size and shape from a larger piece of laminated liquid crystal film and likewise to form tear lines in the resulting sized and shaped piece of laminated liquid crystal film, the power and/or scan speed and/or continuous or pulsed operation of the laser may be adjusted to obtain different depths of penetration for these different operations.
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[0046] In step 920, a first tear line may be formed in a first PET layer of the laminated liquid crystal film. In step 930, a second tear line may be formed in a second PET layer of the laminated liquid crystal film. Between step 920 and step 930, the liquid crystal film may be reoriented or flipped to permit the laser beam to be incident upon the desired PET surface. Steps 920 and 930 may be performed sequentially or may be performed with iterations of other steps (such as steps 940 and 950, described below) between the performance of step 920 and step 930.
[0047] In step 940, the first PET layer may be removed at the first tear line formed in step 920. Step 940 may comprise mechanically peeling the first PET layer from the liquid crystal film. Step 940 may optionally remove a first electrical contact layer from the laminated liquid crystal film.
[0048] After step 940, in step 950 the liquid crystal layer exposed in step 940 may be removed. If any portion of the first electrical contact layer remain after step 940, step 950 may remove that portion of the first electrical contact layer as well. Step 950 may include the use of a solvent (such as alcohol) and/or a mechanical process to expose a second electrical contact layer on the opposing side of the liquid crystal layer to be removed in step 950.
[0049] In step 960, the second PET layer may be removed at the second tear line formed in step 930. Step 960 may comprise mechanically peeling the second PET layer from the liquid crystal film. Step 960 may optimally remove a second electrical contact layer from the laminated liquid crystal film as well.
[0050] In step 970, the liquid crystal layer exposed in step 960 may be removed. If any portion of the second electrical contact layer remains after step 960, step 970 may be used to remove that portion of the second electrical contact layer as needed. Step 970 may use a solvent (such as alcohol) and/or mechanical process to expose a first electrical contact layer on the opposing side of the liquid crystal layer to be removed in step 970.
[0051] The steps depicted in the exemplary method 900 of
[0052] In addition to the steps of the exemplary method 900 depicted in the present example, additional steps may be performed. For example, a laser or other device may be used initially to cut a shaped liquid crystal film of at least approximately the desired dimensions and configuration for further processing, in which case the power and/or scan rate of a laser used may differ from the laser used in the exemplary method described herein (although the same laser need not be used if this optional pre-forming step is included). Further, the appropriate electrical connections may be made to enable the remaining liquid crystal layer to be switched between a first state and a second state. The resulting processed laminated liquid crystal film may be assembled and/or installed into a product, such as vision training eyewear, as desired.
[0053] Different types of laser cuts may be achieved by moving and/or powering a laser in different patterns. For example, a laser may be moved at a fixed rate while powered at a consistent level, which will result in a uniform depth of penetration of the laser through a PET layer (assuming the material contacted by the laser is uniform). By way of further example, a laser may be moved to a first position, activated at a first power while stationary in that first position for a first period of time, deactivated after the first period of time, and then moved to a second position to be activated for a second period of time at a second power, and so on for multiple positions, powers and periods of time. In such a further example, the time period for which a laser is activated and the power at which the laser is activated may be the same for all positions, thereby creating a uniform depth of penetration at all positions (again, assuming that the material is uniform for all positions), and the positions at which the laser is activated may be uniformly distributed, thereby creating a uniform perforation of at least one PET layer of a liquid crystal film.
[0054] The use of perforation cuts with an appropriate duty cycle for the liquid crystal film to be cut may be particularly useful for trimming a liquid crystal film affixed to a polycarbonate layer. For example, a liquid crystal film affixed to a polycarbonate panel may extend beyond the edges of the polycarbonate. Using systems and methods in accordance with the present invention, a perforation may be formed entirely through the liquid crystal film (that is, through a first PET layer, the liquid crystal and electrical contact layers, and then the second PET layer) that permits the physical separation of the portion of the liquid crystal film extending beyond the polycarbonate layer while leaving undamaged electrical contact layer(s) between the locations where the perforations were made, thereby permitting the liquid crystal layer of the liquid crystal film to be electrically controlled from the perimeter. In example for use in vision training eyewear, such a perforation may be used to conform the liquid crystal film to a protective polycarbonate layer and to expose one or both electrical contact layers at one or more perimeter locations, while one or more additional cuts in accordance with the present invention may be made at an interior location (such as the bridge or nose portion of the eyewear) to expose an electrical contact layer to control the portion of a liquid crystal film corresponding to the eye of the individual wearing the eyewear.
[0055] System and methods in accordance with the present invention enable a single liquid crystal film to be processed to provide multiple regions that may each be independently controlled. One way to control multiple regions created in a liquid crystal film in accordance with the present invention is to provide a single common contact for all of the multiple regions and an individual control contact for each of the individual regions. For example, a single liquid crystal film may be processed to create two, three, four or more regions sharing one electrical contact and an additional discrete contact for each of the individual regions. For eyewear, such as depicted in one example in
[0056] While described in examples herein for use in processing laminated liquid crystal films for use in vision training eyewear, the present invention is not limited to any specific use of the liquid crystal films formed. The laminated liquid crystal films created using systems and methods in accordance with the present invention may be used for any purpose within the scope of the present invention.
[0057] The present invention is further not limited to any particular type of laminated liquid crystal film. Laminated liquid crystal films having external layers other than the PET layers described herein may be processed in accordance with the present invention. While the electrical contact layers of exemplary laminated liquid crystal films are described as metalized layers in some embodiments, other types of electrical contact layers may be used in laminated liquid crystal films processed in accordance with the present invention. Further, the present invention is not limited to any particular type of liquid crystal film.
[0058] Further, laminated liquid crystal films processed in accordance with the present invention may be assembled into structures having more or fewer layers than those shown in examples herein, as well as different types of layers than depicted in examples herein. In some examples, a single protective polycarbonate layer may be used, while in other examples additional layers, such as may be added to provide additional impact protection and/or light filtering, ay be assembled with a laminated liquid crystal film to be processed in accordance with the present invention.