TRANSPARENT MATERIAL PROCESSING WITH AN ULTRASHORT PULSE LASER

• US 20130183474A1
• Filed: 02/13/2013
• Published: 07/18/2013
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Bovatsek, James, Arai, Alan Y., Yoshino, Fumiyo
• Granted Patent: US 9,636,773 B2
• Time in Patent Office: Days
• US Class Current: 428/43
• 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

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. This enables clean breaking of transparent materials at a higher speed than conventional techniques.

Claims

1. A method of scribing a transparent material, comprising:

using a single pass of a focused beam of ultrashort laser pulses to create a surface groove in said material and at least one modified region within the bulk of said material during motion of said transparent material relative to said focused laser beam,

wherein an intensity of said focused beam produces non-linear absorption within a material region, and said ultrashort pulses are generated at a repetition rate sufficiently high such that spatial overlap between said pulses, and interaction between said laser pulses and a modified region, creates at least one additional region of material modification within the material,

wherein said surface groove and said at least one modified region are each formed by interaction of said focused beam with said material, said surface groove in said material and said at least one modified region within the bulk being formed along a beam propagation direction, and

wherein said surface groove and said at least one modified region are discontinuous and separated in depth.

2. The method according to claim 1, wherein a location of said surface groove and said at least one modified region are separated by a determined distance.

3. The method according to claim 1, wherein said transparent material comprises sapphire.

4. A method for scribing a transparent material, comprising:

using a single pass of a focused beam of ultrashort laser pulses to create a plurality of modified regions within the bulk of said material during motion of said transparent material relative to the focused laser beam, wherein said method comprises focusing said beam within the bulk of said material such that an intensity of said focused beam produces non-linear absorption within said material and causes first material modification at a first location within said material in the beam propagation direction and second material modification at a second location at a greater distance along said beam propagation direction within said material,

wherein each of said first and second material modifications are formed along said beam propagation direction as discontinuous regions separated in depth,

wherein said beam of ultrashort pulses is generated at a repetition rate sufficiently high such that said first and second material modifications are formed with spatially overlapping pulses during said single pass.

5. The method according to claim 4, wherein said first location is at or near the surface of the material.

6. A transparent material scribed at two or more locations in a depth direction thereof with a single pass of a focused beam of ultrashort laser pulses,

wherein said scribed locations comprise a surface groove scribed in said material and at least one scribe feature formed in the bulk of said material,

wherein said surface groove and said at least one scribe feature are formed along said beam propagation direction, said surface groove and said at least one scribe feature being discontinuous and separated in depth, and

wherein a location of said surface groove and said at least one scribe feature are separated by a determined distance.

7. A method of scribing a transparent material, comprising:

irradiating said material with a beam of focused and spatially overlapping ultrashort laser pulses, in a single pass and during motion of said transparent material relative to said focused laser beam, to modify said material at two or more locations in a depthwise direction thereof, wherein an intensity of said focused beam produces non-linear absorption within a material region,

wherein at least a portion of said irradiating is carried out with a diffractive optical element that generates multiple regions of high optical intensity at different depthwise locations along a propagation axis of said focused laser beam, said diffractive optical element receiving an input beam and generating multiple laser modified discontinuous regions separated in depth.

8. The method of claim 7, wherein a surface groove is formed in said material, and at least one modified region is formed within the bulk of said material.

9. A method of scribing a transparent material, comprising:

generating a zero-th order Bessel beam of laser light, and

irradiating said material in a single pass with said beam during motion of said transparent material relative to the beam to modify said material at two or more locations in a depthwise direction thereof using multiple regions of high optical intensity generated by said beam at different depthwise locations within said material,

wherein an intensity of said beam produces non-linear absorption within said material.

10. The method according to claim 9, wherein a surface groove is formed in said material, and at least one modified region is formed within the bulk of said material.

11. A system for scribing a transparent material, comprising:

an ultrashort laser source to generate a beam of ultrashort laser pulses;

an optical system to focus and deliver said beam of ultrashort laser pulses to said material with optical intensity sufficiently high so as to produce non-linear absorption within said material; and

a motion system to produce motion of said transparent material relative to said focused laser beam, said motion system operatively connected to said ultrashort laser source and said optical system,

wherein said system is configured in such a way that said ultrashort pulses are generated at a repetition rate sufficiently high such that first and second material modifications are simultaneously formed with spatially overlapping pulses during said motion and in a single pass of said laser beam with respect to said material.