Laser welding of transparent and opaque materials
09787345 · 2017-10-10
Assignee
Inventors
Cpc classification
B29C66/73116
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24777
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
C04B2237/78
CHEMISTRY; METALLURGY
B29C65/1638
PERFORMING OPERATIONS; TRANSPORTING
B23K2103/42
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24322
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
Y10T428/13
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
H05K5/066
ELECTRICITY
B23K2101/36
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24339
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
B23K26/32
PERFORMING OPERATIONS; TRANSPORTING
B32B7/03
PERFORMING OPERATIONS; TRANSPORTING
B29C66/73361
PERFORMING OPERATIONS; TRANSPORTING
H04M1/724
ELECTRICITY
B29C65/1629
PERFORMING OPERATIONS; TRANSPORTING
B32B38/0008
PERFORMING OPERATIONS; TRANSPORTING
C04B2237/76
CHEMISTRY; METALLURGY
B29C66/72
PERFORMING OPERATIONS; TRANSPORTING
B32B3/02
PERFORMING OPERATIONS; TRANSPORTING
B29C66/02
PERFORMING OPERATIONS; TRANSPORTING
B32B37/18
PERFORMING OPERATIONS; TRANSPORTING
B29C66/30325
PERFORMING OPERATIONS; TRANSPORTING
B29C66/242
PERFORMING OPERATIONS; TRANSPORTING
B29C66/303
PERFORMING OPERATIONS; TRANSPORTING
B23K2103/50
PERFORMING OPERATIONS; TRANSPORTING
G06F1/1626
PHYSICS
H04M1/0249
ELECTRICITY
B29C66/73365
PERFORMING OPERATIONS; TRANSPORTING
B32B2457/20
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24521
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
B23K26/57
PERFORMING OPERATIONS; TRANSPORTING
B23K26/40
PERFORMING OPERATIONS; TRANSPORTING
B32B37/142
PERFORMING OPERATIONS; TRANSPORTING
B23K26/10
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24488
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
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
H04M1/026
ELECTRICITY
B32B37/06
PERFORMING OPERATIONS; TRANSPORTING
B32B3/266
PERFORMING OPERATIONS; TRANSPORTING
B29C66/1162
PERFORMING OPERATIONS; TRANSPORTING
B23K2103/08
PERFORMING OPERATIONS; TRANSPORTING
Y10T428/24331
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
G06F1/1637
PHYSICS
B29C65/1654
PERFORMING OPERATIONS; TRANSPORTING
B29L2031/3481
PERFORMING OPERATIONS; TRANSPORTING
B32B7/05
PERFORMING OPERATIONS; TRANSPORTING
International classification
B23K26/10
PERFORMING OPERATIONS; TRANSPORTING
B23K26/57
PERFORMING OPERATIONS; TRANSPORTING
B32B37/12
PERFORMING OPERATIONS; TRANSPORTING
B23K26/40
PERFORMING OPERATIONS; TRANSPORTING
B23K26/32
PERFORMING OPERATIONS; TRANSPORTING
B32B7/02
PERFORMING OPERATIONS; TRANSPORTING
B32B3/02
PERFORMING OPERATIONS; TRANSPORTING
B32B37/06
PERFORMING OPERATIONS; TRANSPORTING
B32B38/00
PERFORMING OPERATIONS; TRANSPORTING
B23K26/00
PERFORMING OPERATIONS; TRANSPORTING
B32B37/14
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Welding of transparent material in electronic devices. An electronic device may include an enclosure having at least one aperture formed through a portion of the enclosure. The electronic device may also include a component positioned within the aperture formed through the portion of the enclosure. The component may be laser welded to the aperture formed through the enclosure. Additionally, the component may include transparent material. A method for securing a component within an electronic device may include providing an electronic device enclosure including at least one aperture, and positioning a component within the aperture formed through the enclosure. The component positioned within the aperture may include a transparent material. The method may also include welding the component to the electronic device enclosure.
Claims
1. An apparatus, comprising: an enclosure having a first melting temperature, comprising: an exterior surface; an interior surface opposite the exterior surface; and a sidewall extending between the exterior and interior surfaces and defining an aperture; a transparent component positioned within the aperture and having a second melting temperature that is greater than the first melting temperature and having a first surface and a second surface opposite the first surface connected by a side surface defining an edge having at least one surface defect, wherein the at least one surface defect is the result of a forming process of the transparent component comprising a crack or depression; and a laser weld formed between the sidewall of the enclosure and the edge of the transparent component and encircling the transparent component within the aperture, the laser weld generated by passing a laser beam onto the sidewall to heat the sidewall to a temperature that is greater than first melting temperature and less than the second melting temperature, wherein the laser weld includes a portion of the enclosure filling the at least one surface defect of the transparent component.
2. The apparatus of claim 1, wherein the enclosure comprises at least one of: sapphire; metal; glass; or plastic.
3. The apparatus of claim 1, wherein the transparent component comprises at least one of: sapphire; glass; or plastic.
4. The apparatus of claim 1, wherein a size of the aperture at the interior surface of the enclosure is greater than a size of the aperture at the exterior surface.
5. The apparatus of claim 1, wherein the sidewall includes a bezel portion.
6. The apparatus of claim 1, wherein the sidewall is angled and the edge is beveled.
7. The apparatus of claim 1, wherein the first and/or second surfaces of the transparent component is/are treated.
8. The apparatus of claim 1, wherein the aperture is substantially circular.
9. The apparatus of claim 1, wherein the transparent component includes at least one of: a button a transparent layer for a display; or a window for a camera system.
10. The apparatus of claim 1, wherein the transparent component forms at least a portion of an exterior surface of an electronic device.
11. A method for forming an apparatus comprising: providing an enclosure having a first melting temperature, the enclosure comprising: an exterior surface; an interior surface opposite the exterior surface; and a sidewall extending between the exterior and interior surfaces and defining an aperture; positioning a transparent component having a second melting temperature that is greater than the first melting temperature within the aperture, the transparent component having a first surface and a second surface opposite the first surface connected by a side surface defining an edge having at least one surface defect, wherein the at least one surface defect is the result of a forming process of the transparent component comprising a crack or depression; and forming a laser weld between the sidewall of the enclosure and the edge of the transparent component that encircles the transparent component within the aperture, the laser weld is generated by a laser beam heating the sidewall to a temperature that is greater than first melting temperature and less than the second melting temperature, wherein the laser weld includes a portion of the aperture filling the at least one surface defect of the transparent component.
12. The method of claim 11, further comprising: surface treating a first surface of the transparent component; and surface treating a second surface of the transparent component opposite the first surface.
13. The method of claim 12, wherein the positioning comprises aligning the treated first surface of the transparent component and the exterior surface of the enclosure.
14. The method of claim 11, further comprising: prior to the positioning of the component within the aperture, applying an adhesive to at least one of: the aperture; or the window.
15. The method of claim 11, wherein the forming process comprises at least one of: cutting; or shaping.
16. The method of claim 11, wherein the laser weld is generated by passing a laser beam through the transparent component onto the sidewall.
17. An apparatus, comprising: an enclosure having a first melting temperature, comprising: an exterior surface; an interior surface; and a sidewall formed on interior surface defining an aperture; a transparent component positioned within the aperture and having a second melting temperature that is greater than the first melting temperature and having a first surface and a second surface opposite the first surface connected by a side surface defining an edge having at least one surface defect, wherein the at least one surface defect is the result of a forming process of the transparent component comprising a crack or depression; and a laser weld formed between the sidewall of the enclosure and the edge of the transparent component and encircling the transparent component within the aperture, the laser weld is generated by a laser beam heating the sidewall to a temperature that is greater than first melting temperature and less than the second melting temperature, wherein the laser weld includes a portion of the enclosure filling the at least one surface defect of the transparent component.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12) It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.
DETAILED DESCRIPTION
(13) Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
(14) The following disclosure relates generally to electronic devices, and more particularly, to transparent materials included in electronic devices and methods for securing transparent materials in electronic devices.
(15) Discussed herein are apparatuses including transparent materials, transparent materials used in electronic devices and methods for securing transparent materials in electronic devices. The apparatuses and electronic devices typically include two components: a first component (one example of which is an enclosure) having an aperture; and a second component which includes the transparent material. The second component is positioned within the aperture of the first component and is laser welded directly to the first component.
(16) More specifically, a laser is positioned above the first and second component and emits a beam through the second component, including the transparent material, to the first component to form a laser weld between the respective components. By welding the first component to the second component, the need for an adhesive to bind the components may be unnecessary, and a substantially permanent coupling may be formed between the components. Additionally, in some embodiments, by forming the laser weld between the first and second component by emitting a laser beam through the second component, the weld may be substantially hidden from the user of the electronic device. That is, by laser welding the respective components, the weld may be substantially undetectable by, or concealed from, the user of the electronic device. Not only may the laser weld improve the coupling strength between the first and second component, but it may also improve the cosmetic features of the electronic device.
(17) These and other embodiments are discussed below with reference to
(18)
(19) Electronic device 100 may include an enclosure 102 at least partially surrounding a display 104 and one or more buttons 106 or input devices. The enclosure 102 may form an outer surface or partial outer surface and protective case for the internal components of the electronic device 100, and may at least partially surround the display 104. The enclosure 102 may be formed of one or more components operably connected together, such as a front piece and a back piece. In a non-limiting example, where enclosure 102 may be formed from a plurality of components, enclosure 102 may include a trim piece that may be coupled to additional components configured to be operably connected to form a protective case for electronic device 100, as discussed herein. Alternatively, the enclosure 102 may be formed of a single piece operably connected to the display 104. Enclosure 102 may include a plurality of distinct materials including, but not limited to: corundum, commonly referred to as sapphire, metal, glass or plastic. Additionally, enclosure 102 may include a decorative and/or coating layer that be disposed on the outer and/or or inner surface of enclosure 102. The decorative layer and/or coating layer may be disposed on the surface(s) of enclosure 102 to protect the enclosure and/or provide a decorative feature (e.g., exterior color) for electronic device 100.
(20) Display 104 may be implemented with any suitable technology, including, but not limited to, a multi-touch sensing touchscreen that uses liquid crystal display (LCD) technology, light emitting diode (LED) technology, organic light-emitting display (OLED) technology, organic electroluminescence (OEL) technology, or another type of display technology. Display 104 may include a substantially transparent layer 108 positioned above the touchscreen. That is, and as discussed herein, transparent layer 108 may be positioned above the touchscreen of display 104 and may be positioned within an aperture of enclosure 102, such that enclosure 102 and transparent layer 108 are in planar alignment with front surface 112 of electronic device 100. Transparent layer 108 may protect display 104 from containments, without obstructing a user's view and/or ability to interact with display 104 and/or electronic device 100. Transparent layer 108 may be formed from a variety of substantially transparent materials including, but not limited to: sapphire, glass or plastic.
(21) Button 106 may include any conventional input/output (I/O) device for electronic device 100. Specifically, button 106 may include an actuation component (see,
(22) As shown in
(23)
(24) As shown in
(25) The plurality of apertures (e.g., aperture 124) of enclosure 102 may be configured to receive a component or components (such as, window 122, transparent layer 108 of display 104, button 106) of electronic device 100 by having a complementary shape of the component, which includes any shape configured to accept and/or retain such a component. As discussed herein, by including complementary shapes, the component of electronic device 100 positioned within the aperture of enclosure 102 may also be adequately coupled (e.g., welded) to enclosure 102 of electronic device 100.
(26) In an non-limiting example, as shown in
(27) Second camera system 118 may include internal camera components 134 positioned adjacent window 122. Internal camera components 134 may be positioned within internal cavity 128 of electronic device 100, adjacent interior surface 126 of enclosure 102. As shown in
(28) Window 122 of second camera system 118 may include a first surface 136 and a second surface 138 positioned opposite first surface 136. As discussed herein, when window 122 is positioned within enclosure 102, first surface 136 may be an external surface and may be substantially exposed to the exterior of electronic device 100 and/or may be in planar alignment with the exterior surface or back surface 120 of electronic device 100. Furthermore, and as discussed herein, when window 122 is positioned within enclosure 102, second surface 138 may include an internal surface positioned adjacent interior surface 126 of enclosure 102 and/or may be positioned within cavity 128 of electronic device 100.
(29) First surface 136 and second surface 138 of window 122 may include surface treatments. More specifically, prior to, or subsequent to, positioning window 122 within enclosure 102, first surface 136 and second surface 138 may undergo surface treatment processes including, but not limited to: lapping, planing, grinding, or polishing. In a non-limiting example, first surface 136 and second surface 138 may be polished prior to positioning window 122 within enclosure 102 to substantially ensure that window 122 includes an acceptable transparency that will not obstruct second camera system 118. The surface treatment processes may be performed on window 122 prior to and/or subsequent to the forming (e.g., cutting, shaping) of window 122.
(30) As shown in
(31) As a result of not performing surface treatment processes on sidewalls 132, untreated sidewalls 132 of window 122 may include defects 140.
(32)
(33) Window 122 may also be coupled to enclosure 102. More specifically, as shown in
(34) In coupling window 122 to enclosure 102, a weld interface 146 may be present between sidewalls 130 of enclosure 102 and untreated sidewalls 132 of window 122 to couple the components of electronic device 100. As shown in
(35)
(36) As a result of angled sidewalls 132 of window 122 and corresponding angled sidewalls 130 of enclosure 102, weld interface 146 may not be visible to a user of electronic device 100. More specifically, because the respective angled sidewalls for window 122 and enclosure 102 extend toward internal cavity 128 and/or enclosure 102, a user of electronic device 100 viewing back surface 120 may not be able to see weld interface 146. As such, a “hidden weld” may be formed to couple window 122 to enclosure 102 of electronic device 100.
(37)
(38) Transparent layer 108 of electronic device 100 may include first surface 336, which may be exposed to a user. More specifically, as shown in
(39) As shown in
(40) As similarly discussed herein with respect to window 122, first surface 336 and second surface 338 of transparent layer 108 may include a surface treatment. That is, first surface 226 and second surface 338 of transparent layer 108 may undergo surface treatment(s) prior to transparent layer 108 being positioned within aperture 324 of enclosure 102. To the contrary of treated first surface 336 and treated second surface 338, but similar to sidewalls 132 of window 122 in
(41) Similar to window 122 shown in
(42) As shown in
(43) Although shown and discussed herein as being used with transparent layer 108, it is understood that adhesive 348 of
(44)
(45) As shown in
(46) By providing weld interface 146 between protrusion portion 458 of button housing 452 and bezel portion 456 of enclosure 102, weld interface 146 may not be visible, or may be “hidden” from a user viewing front surface 112 of electronic device 100. More specifically, bezel portion 456 of enclosure 102 may be positioned on top of and/or may extend over protrusion portion 458 of button housing 452, such that protrusion portion 458 is not visible from front surface 112 of electronic device 100. As a result, weld interface 146 may also be covered and/or not visible from front surface 112 because of bezel portion 456.
(47) Turning to
(48) In operation 502, an electronic device enclosure including at least one aperture is provided. More specifically, at least one aperture may be formed through an enclosure of an electronic device for allow components of the electronic device to be viewable by a user and/or protected from contaminants.
(49) In optional operation 504, an adhesive may be applied to at least one of the at least one aperture formed through the electronic device enclosure, and/or a component configured to be positioned within the aperture. That is, an adhesive may be applied to a portion of the sidewalls of the apertures formed through the electronic device enclosure. Additionally, an adhesive may be applied to a portion of the component that may contact the sidewalls of the apertures when the component is positioned within the aperture. As discussed herein, the adhesive may be applied to the aperture and/or the component to adhere the component to the enclosure and/or hide a weld formed between the electronic device enclosure and the component.
(50) In operation 506, the component may be positioned within the aperture formed through the electronic device enclosure. More specifically, a component of the electronic device, formed from a transparent material, may be positioned within and/or received by the aperture of the electronic device enclosure. As discussed herein, the aperture of the enclosure may include a complementary shape to the shape of the component. That is, the sidewalls of the aperture of the enclosure may be complementary to the sidewalls of the component positioned within the enclosure. In non-limiting examples, and as discussed herein, the component positioned within the aperture of the enclosure may include a window for a camera system (see,
(51) The component positioned within the aperture of the electronic device enclosure may include additional processes prior to, or subsequent to, the positioning in operation 506. More specifically, the an external surface of the component may be treated, and the internal surface of the component positioned opposite the external surface may be treated. The external surface and internal surface may undergo surface treatments, such as, lapping, planing, grinding, or polishing. Additionally, prior to, subsequent to, and/or during the positioning in operation 506, untreated sidewalls of the component may be substantially maintained. More specifically, the sidewalls of the component may remain substantially untreated, or may not undergo surface treatments, such that the sidewalls contain defects (e.g., cracks, depressions) formed during initially processes for creating the component.
(52) The positioning in operation 506 may also include aligning the treated external surface of the component with an exterior surface of the electronic device enclosure. More specifically, when positioning the component within the aperture, the treated external surface of the component may be in planar alignment with an exterior surface of the enclosure. By aligning the external surface of the component and the exterior surface of the enclosure, the surface of the electronic device including the component and/or the aperture may be substantially continuous and planar.
(53) In operation 508, the component may be welded to the electronic device enclosure. More specifically, a laser beam may be projected through the component including the transparent material, and a portion of the sidewall of the aperture formed through the enclosure may be exposed to the projected laser beam. The laser beam wavelength may be dependent on the material composition of the component, such that material of the component is transparent to the laser beam. As a result of the laser beam being projected through the component, the material of the component may also include a melting point greater than the melting point of the material forming the enclosure. When the laser beam is exposed to a portion of the sidewall of the enclosure through the component, the exposed portion of the sidewall may include a solidified molten pool that may weld the sidewall of the component to the sidewall of the aperture of the enclosure. The welding may also include laser welding an entire perimeter of the component to the at least one aperture formed through the enclosure. By welding the perimeter of the component, it may substantially ensure that the component is fixed to the enclosure.
(54) Turning to
(55) As shown in
(56) Also shown in
(57) Although not shown in
(58) Turning to
(59) In a non-limiting example, where window 122 is formed from sapphire and enclosure 102 is formed from aluminum, laser 660 may include an infrared laser, which may produce laser beam 662 having a 1064 nm wavelength, and 150 W average power. Laser 660 may be a pulsed laser capable of pulsing laser beam 662 in micro-second pulse widths. Because sapphire's melting point (e.g., approximately 2000° C.) is greater than aluminum's melting point (e.g., approximately, 1220° C.), laser beam 662 pulsing through window 122 may form a molten pool of the aluminum on sidewall 130, which may ultimately create weld interface 146 (see,
(60) Window 122 may be substantially circular in shape (see,
(61) As shown in
(62) Although the material forming window 122 is discussed herein as having a melting point higher than the material forming the enclosure 102, it is understood that window 122 may also include a melting point equal to or less than the melting point of the material forming the enclosure 102. That is, in non-limiting examples, the material forming window 122 may include a melting point equal to, or less than the material forming enclosure 102. In these examples, window 122 may remain substantially unaffected when laser beam 662 is projected through window 122, as discussed herein, or may be minimally altered by laser beam 662. In these non-limiting examples, when window 122 is exposed to laser beam 662, window 122 may be substantially unaffected by laser beam 662, as discussed herein, or laser beam 662 may cause a minimal, surface alteration to window 122. Although the material forming window 122 may include a melting point equal to, or less than the material forming enclosure 102, window 122 may remain substantially unaffected or minimally affected as a result of laser beam 662 including a wavelength that provides window 122 to be substantially transparent to laser beam 662 of laser 660. Where window 122 includes a minimal surface alteration as a result of laser beam 662, the minimal surface alteration may remain on second surface 138 of window 122 undetectable and/or unseen by a user or, may be removed by performing additional surface treatment processes (e.g., buffing, polishing) on second surface 138 of window 122.
(63) By welding the components (e.g., window, button) of the electronic device to the enclosure of the electronic device, the need for an adhesive to bind the components is unnecessary. Also, in welding the components of the electronic device to the enclosure, the need for decorative ink to hide the coupling technique (e.g., the weld) may be unnecessary, as the weld is substantially small and/or undetectable by a user of the electronic device. Additionally, by welding the components to the enclosure of the electronic device, a substantially permanent coupling may be formed between the components and the enclosure. Furthermore, by forming the laser weld between the components and the enclosure by emitting a laser beam through the transparent material forming the components, the weld may be substantially hidden from the user of the electronic device. That is, by laser welding the respective components, the weld may be substantial undetectable by, or concealed from, the user of the electronic device. Not only will the laser weld improve the coupling strength between the first and second component, but it may also improve the cosmetic features of the electronic device.
(64) The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.