TRANSPARENT MATERIAL PROCESSING WITH AN ULTRASHORT PULSE LASER

• US 20130095260A1
• Filed: 11/16/2012
• Published: 04/18/2013
• Est. Priority Date: 09/08/2005
• Status: Abandoned Application

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: BOVATSEK, James, Arai, Alan Y., Yoshino, Fumiyo
• Application Number:
  US13/679,230
• Publication Number:
  US 20130095260A1
• Time in Patent Office: Days
• US Class Current: 428/34.1
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/0617 and with spots spaced along the common axis
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/244 Overlap seam welding
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/53 for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: B29C 59/16 by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: B29C 65/00 Joining or sealing of preformed parts , e.g. welding of plastics materials; Apparatus therefor general aspects of processes or apparatus for joining preformed parts B29C66/00; using porous material formed by internal pressure generated therein for joining preformed parts B29C44/1228, B29C44/326
• CPC Class Codes: B29C 65/14 using wave energy , i.e. electromagnetic radiation, or particle radiation using mechanical waves B29C65/06; using ultrasonic waves B29C65/08; pressing means transparent to electromagnetic radiation B29C66/81267
• CPC Class Codes: B29C 65/1616 Near infrared radiation [NIR], e.g. by YAG lasers
• CPC Class Codes: B29C 65/1635 at least passing through one of the parts to be joined, i.e. laser transmission welding
• CPC Class Codes: B29C 65/1638 focusing the laser beam on the interface
• CPC Class Codes: B29C 65/1658 scanning once, e.g. contour laser welding
• CPC Class Codes: B29C 65/1664 making use of several radiators
• CPC Class Codes: B29C 65/1674 making use of laser diodes B29C65/167 takes precedence
• CPC Class Codes: B29C 65/1696 making use of masks
• CPC Class Codes: B29C 65/38 Impulse heating
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/30223 : said melt initiators being rib-like
• CPC Class Codes: B29C 66/322 : Providing cavities in the joined article to collect the burr
• CPC Class Codes: B29C 66/3282 : for reinforcing the joint
• CPC Class Codes: B29C 66/41 : Joining substantially flat articles B29C66/47 and subgroups take precedence; Making flat seams in tubular or hollow articles B29C66/51 and subgroups take precedence
• CPC Class Codes: B29C 66/43 : Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/71 : characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/73366 : both parts to be joined being transparent or translucent to visible light
• CPC Class Codes: B29C 66/7352 : Thickness, e.g. very thin
• CPC Class Codes: B29C 66/73921 : characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/836 : Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table B29C66/65 takes precedence
• CPC Class Codes: B29C 66/91641 : the heat or the thermal flux being non-constant over time
• CPC Class Codes: B29C 66/919 : characterised by specific temperature, heat or thermal flux values or ranges specific electrical resistance values B29C66/81262
• CPC Class Codes: B29C 66/934 : by controlling or regulating the speed
• CPC Class Codes: B29C 66/939 : characterised by specific speed values or ranges
• CPC Class Codes: B29C 66/944 : by controlling or regulating the time
• CPC Class Codes: B29C 66/949 : characterised by specific time values or ranges
• CPC Class Codes: B29K 2033/12 : Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0026 : Transparent
• CPC Class Codes: B81B 1/00 : Devices without movable or flexible elements, e.g. microcapillary devices
• CPC Class Codes: B81C 1/00119 : Arrangement of basic structures like cavities or channels, e.g. suitable for microfluidic systems
• CPC Class Codes: C03B 23/20 : Uniting glass pieces by fusing without substantial reshaping
• CPC Class Codes: C03B 23/203 : Uniting glass sheets C03B23/24 takes precedence
• CPC Class Codes: C03B 33/0222 : Scoring using a focussed radiation beam, e.g. laser
• CPC Class Codes: C03C 23/0025 : by a laser beam
• CPC Class Codes: Y10T 428/13 : Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/15 : Sheet, web, or layer weakened to permit separation through thickness
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24802 : Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

Methods for ultrashort pulse laser processing of optically transparent materials. A method for scribing transparent materials uses ultrashort laser pulses to create multiple scribe features with a single pass of the laser beam across the material, with at least one of the scribe features being formed below the surface of the material. Slightly modifying the ultrashort pulse laser processing conditions produces sub-surface marks. When properly arranged, these marks are clearly visible with side-illumination and not clearly visible without side-illumination. In addition, a method for welding transparent materials uses ultrashort laser pulses to create a bond through localized heating. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials.

Claims

1. A method for bonding transparent materials, comprising:

focusing a beam of ultrashort laser pulses near an interface between said materials; and

producing said ultrashort laser pulses at a repetition rate in the range from 100 KHz to 100 MHz and with one or more zones of fluence sufficient to induce localized melting of said materials at said interface.

2. The method of claim 1, wherein said bonding is carried out without a requirement for a supplemental bonding agent or an intermediate light absorbing layer.

3. The method of claim 1, wherein a focused beam of ultrashort pulses induces non-linear absorption of energy in said transparent material(s).

4. A microfluidic system comprising transparent material(s) bonded using the method of claim 1.

5. A microfluidic system according to claim 4, wherein said bonded transparent material(s) are arranged without an intermediate light absorbing layer therebetween.

6. A method for welding transparent materials, comprising:

directing a beam of ultrashort laser pulses to near an interface between said materials, to induce non-linear absorption of energy proximate at least one high intensity region of said beam, to deposit and accumulate heat at said region with repeated pulses at a repetition rate sufficiently high to cause localized melting of said materials.

7. A method for creating a raised ridge at the interface between two opposed surfaces to be welded to fill a gap that cannot be bridged by welding alone, comprising:

focusing ultrashort laser pulses below one or both of the opposed surfaces on which the ridge is to be formed, to raise the ridge; and

subsequently laser welding the raised ridge and the opposite surface or ridge.

8. An optical system for welding transparent materials, comprising:

a laser system that produces a beam of femtosecond to picosecond ultrashort laser pulses having pulse widths in the range from about 50 fs to 500 ps; and

a focusing element for focusing said beam near an interface between said materials, wherein said laser system has a pulse repetition rate in the range from 100 kHz to 100 MHz, and said pulses have a zone of higher fluence, which are cumulatively sufficient to induce localized melting of said materials at said interface.

9. A method for welding transparent materials, comprising:

directing a beam of ultrashort laser pulses to near an interface between said materials; and

optically controlling formation and spatial position of one or more areas of high intensity within a body of said materials, to induce melting of said materials only within said zone or zones.