WO2012023429A1 - Procédé de fabrication de plaque à différence de phase et plaque à différence de phase - Google Patents

Procédé de fabrication de plaque à différence de phase et plaque à différence de phase Download PDF

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Publication number
WO2012023429A1
WO2012023429A1 PCT/JP2011/067695 JP2011067695W WO2012023429A1 WO 2012023429 A1 WO2012023429 A1 WO 2012023429A1 JP 2011067695 W JP2011067695 W JP 2011067695W WO 2012023429 A1 WO2012023429 A1 WO 2012023429A1
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Prior art keywords
glass substrate
series
region
beams
laser beams
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PCT/JP2011/067695
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English (en)
Japanese (ja)
Inventor
元司 小野
剛介 吉田
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旭硝子株式会社
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Publication of WO2012023429A1 publication Critical patent/WO2012023429A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/0604—Shaping the laser beam, e.g. by masks or multi-focusing by a combination of beams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
    • B23K26/0676—Dividing the beam into multiple beams, e.g. multifocusing into dependently operating sub-beams, e.g. an array of spots with fixed spatial relationship or for performing simultaneously identical operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/50—Working by transmitting the laser beam through or within the workpiece
    • B23K26/53—Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
    • C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
    • C03C23/0025—Other surface treatment of glass not in the form of fibres or filaments by irradiation by a laser beam

Definitions

  • the present invention relates to a phase difference plate.
  • a phase difference plate (for example, a half-wave plate or a quarter-wave plate) capable of controlling the phase and polarization of light is used in various optical devices.
  • Patent Document 1 proposes a method of manufacturing a retardation plate having a band-like birefringence region in a glass substrate using a laser beam.
  • a glass substrate is irradiated with a plurality of branched beams branched from one laser beam, and this is scanned, so that a large area belt-shaped birefringence region is formed in the glass substrate at one time. Can be formed.
  • a plurality of branched beams are simultaneously irradiated into the glass substrate.
  • the birefringence regions are discretely distributed, and there is a possibility that significant non-uniformity of birefringence occurs in the necessary regions.
  • the thermal effect in each place varies depending on the distance from the branched beam. It has a locally high and low retardation level.
  • a retardation level exists in the glass substrate, there is a problem that the retardation distribution of the obtained retardation plate increases. Such an increase in the retardation distribution affects the polarization state of the light emitted from the retardation plate, and there is a possibility that a desired state cannot be obtained in the emitted light.
  • the retardation plate having such retardation non-uniformity there may be a problem that wavefront aberration increases and the transmittance of incident light decreases.
  • the present invention has been made in view of such a background, and in the present invention, a retardation plate in which retardation distribution is significantly improved and transmittance and / or wavefront aberration with respect to visible light is improved is manufactured. It aims to provide a method. Moreover, it aims at providing such a phase difference plate.
  • a method for producing a retardation plate having a birefringent region in and / or on a glass substrate (A) preparing a glass substrate having first and second surfaces; (B) adjusting a series of laser beams having three or more branch beams so that the focal points of the branch beams can be arranged linearly in or on the glass substrate; (C) a step of controlling the intensity of the series of laser beams so that the intensity of the branched beams on the non-both ends is weaker than the intensity of the branch beams on both ends in the series of laser beams; (D) simultaneously irradiating the series of laser beams in and / or on the glass substrate, and scanning in a direction parallel to the first or second surface;
  • the birefringent region has a length along a direction in which the series of laser beams are scanned, and a width in a direction parallel to a straight line connecting the focal points in the step (b). Is done.
  • step (b) a series of laser beams having four or more branched beams are adjusted,
  • the intensity of the branched beams on the non-end sides may be substantially equal.
  • the glass substrate may have a thickness in the range of 0.1 mm to 3 mm.
  • (E) having a step of disposing the focal position of the series of laser beams along the width direction of the birefringent region; After the step (e), the steps (b) to (d) may be repeated to form the birefringent region having a width in the range of 200 ⁇ m to 50 mm.
  • (F) having a step of disposing the focal position of the series of laser beams along the thickness direction of the glass substrate; After the step (f), the steps (b) to (d) may be repeated to form a plurality of the birefringent regions along the thickness direction of the glass substrate.
  • the step (d) includes While irradiating and scanning a part of the series of laser beams on the glass substrate or on the glass substrate from the first surface side of the glass substrate, From the second surface side of the glass substrate, another part of the series of laser beams may be irradiated and scanned in the glass substrate or on the glass substrate.
  • the step (d) is performed in a state where irradiation of the series of laser beams onto the glass substrate is turned on / off at a predetermined timing, After the step (d), a repeating region of a non-birefringent region and a birefringent region may be formed along the scanning direction of the series of laser beams.
  • the laser output may be modulated during the irradiation of the series of laser beams onto the glass substrate.
  • the method according to the present invention includes a step of placing a mask on the first and / or second surface of the glass substrate before the step (d), After the step (d), a repetitive region of a non-birefringent region and a birefringent region may be formed by the mask along the scanning direction of the series of laser beams.
  • the transmittance of the light transmission region may vary depending on the location.
  • the method according to the invention further comprises: (G) A retardation plate having a step of cutting the glass substrate along the non-birefringent region and having the periphery covered with the non-birefringent region may be obtained.
  • the glass substrate has a birefringent region in and / or on the glass substrate,
  • the birefringent region has a substantially band-like or rectangular parallelepiped shape having a length in a first direction extending parallel to the surface of the glass substrate and a width in a second direction perpendicular to the first direction.
  • the birefringent region is surrounded by a non-birefringent region,
  • the birefringent region has a retardation distribution within ⁇ 10% in a range of 300 ⁇ m along the first and second directions,
  • the retardation plate has an internal transmittance of 98% or more with respect to visible light passing through the birefringent region.
  • the glass substrate may have a thickness of 0.1 mm or more.
  • the birefringence region may have a retardation distribution within ⁇ 5% in a range of 300 ⁇ m along the first and second directions.
  • the birefringence region may have a thickness of 50 ⁇ m to 300 ⁇ m.
  • the birefringence region may have a width in the range of 200 ⁇ m to 50 mm.
  • the present invention it is possible to provide a method for producing a retardation plate in which the retardation distribution is significantly improved and the transmittance with respect to visible light and / or the wavefront aberration is improved. Moreover, it becomes possible to provide such a phase difference plate.
  • FIG. 8 is a cross-sectional view taken along line AA of the retardation plate shown in FIG. 7. It is the top view which showed roughly an example of the glass substrate before cutting out the phase difference plate shown in FIG.
  • FIG. 10 is a cross-sectional view of the glass substrate shown in FIG. 9 taken along line BB.
  • 4 is a graph showing a measurement result of retardation of a quarter wave plate according to Example 1.
  • FIG. 6 is a graph showing a measurement result of retardation of a half-wave plate according to Example 2.
  • 6 is a graph showing a measurement result of retardation of a 1 ⁇ 4 wavelength plate according to Comparative Example 1.
  • 6 is a graph showing a measurement result of retardation of a quarter wave plate according to Comparative Example 2.
  • FIG. 1 schematically shows a state of manufacturing a conventional retardation plate.
  • a birefringence region is formed on the glass substrate 1 by using a laser beam 2, a beam branching element 5, and a lens 3. That is, first, the laser beam 2 is branched into a plurality of (three in the example of FIG. 1) branch beams 6 by the beam branch element 5. Next, the branched beam 6 is condensed by the lens 3 and irradiated onto the glass substrate 1. Further, each branched beam 6 is scanned linearly along the Y direction of FIG. In the region scanned with the laser beam, tensile stress parallel to the scanning direction is generated, and a plurality of rod-shaped birefringent regions parallel to each other as shown in FIG. 4 are formed.
  • a uniaxial birefringent region having a relatively wide area can be formed in the glass substrate 1 by configuring such rod-shaped birefringent regions 4 to be connected to each other.
  • one laser beam 2 is divided into a plurality of branch beams 6, and these branch beams 6 are simultaneously irradiated into the glass substrate 1.
  • the distance between the branched beams 6 is too wide, the non-birefringence region is generated in the birefringence region that should originally be single, and the uniformity of the birefringence region decreases. There is a risk.
  • the retardation distribution increases.
  • the increase in the retardation distribution affects the wavefront state of light transmitted through the retardation plate.
  • a desired state cannot be obtained in the light emitted from the phase difference plate. That is, in the retardation plate obtained by such a method, the wavefront aberration increases, and the light changes its direction of travel and spreads, so that it becomes impossible to transmit the light as it is. There is a possibility that the problem of a decrease in light transmittance in the direction of.
  • the light transmitted through the retardation plate has wavefront aberration, it is difficult to collect such light in a minute region with a lens or the like. May be difficult to use.
  • a method for producing a retardation plate having a birefringent region in and / or on a glass substrate (A) preparing a glass substrate having first and second surfaces; (B) adjusting a series of laser beams having three or more branch beams so that the focal points of the branch beams can be arranged linearly in or on the glass substrate; (C) In the series of laser beams, the intensity of the series of laser beams is controlled so that the intensity of the branch beams on the non-end sides is weaker than the intensity of the branch beams on both ends. (D) simultaneously irradiating the series of laser beams in or on the glass substrate, and scanning in a direction parallel to the first or second surface; This provides a method for forming a birefringent region in the glass substrate.
  • the birefringence region indicates a region having a retardation value of 40 nm or more at a wavelength of 546 nm.
  • the birefringence region is as defined in this definition.
  • the present invention has been obtained by paying attention to the spread of heat generated from the focal point of each branched beam simultaneously irradiated onto the glass substrate. That is, as described above, when it is assumed that the power of each branch beam is equal, the heat from the left-right direction is closer to the focus on the non-end side than the focus on the both ends of each focus of the branch beam. The temperature rises relatively easily due to the diffusion of. For this reason, when the power of each branched beam is made equal and a series of laser beams are irradiated onto the glass substrate, a birefringent region having locally high retardation is generated as a result.
  • the power of the branch beam on the non-end side is smaller than the power of the branch beam on the both end side, more precisely, the power of the branch beam on the non-end side is
  • the glass substrate is irradiated with a series of laser beams selected in consideration of the effect of heat diffused from the focal point, the birefringence region is more uniform by reducing the level of retardation of the formed birefringence region. Can be obtained.
  • the intensity of the central branched beam is made smaller than the intensity of the branched beams on both ends
  • a glass substrate is irradiated with a series of laser beams.
  • the series of lasers are set so that the intensity of the two branched beams at the center side is smaller than the intensity of the branched beams at both ends.
  • the glass substrate is irradiated with light. The same applies when a series of laser beams has five or more branched beams.
  • the intensity of the branched beams on the non-end sides is substantially equal.
  • the retardation plate in which the retardation distribution is significantly suppressed.
  • the retardation distribution can be suppressed within ⁇ 10%, and further within ⁇ 5%.
  • the method according to the present invention can provide a phase difference plate characterized by having an internal transmittance of 98% or more with respect to visible light passing through the birefringent region.
  • the retardation plate according to the present invention can be used in a condensing optical system such as an optical pickup.
  • the wavefront aberration is preferably 20 m ⁇ or less, and more preferably 15 m ⁇ or less.
  • FIG. 2 shows a schematic flow diagram of one method for producing a retardation plate according to the present invention.
  • the method of manufacturing the retardation plate according to the present invention includes: (A) preparing a glass substrate having first and second surfaces (step S110); (B) A step of adjusting a series of laser beams having three or more branch beams, wherein the focal points of the branch beams are linearly arranged in or on the glass substrate (Ste S120) (C) In the series of laser beams, the step of controlling the intensity of the series of laser beams so that the intensity of the branch beams on the non-end sides is weaker than the intensity of the branch beams on both ends (step S130).
  • step S140 simultaneously irradiating the series of laser beams in or on the glass substrate and scanning in a direction parallel to the first or second surface
  • the glass substrate which comprises a phase difference plate is prepared.
  • the composition of the glass substrate is not particularly limited.
  • the glass substrate may be, for example, soda lime glass, borosilicate glass, and silica glass.
  • glass doped with a transition metal or the like may be used as the glass substrate in order to increase the absorption coefficient at the wavelength of the laser beam to be used.
  • the thickness of the glass substrate is not particularly limited.
  • the thickness of the birefringent region can be, for example, about 100 ⁇ m.
  • a thin glass substrate having a thickness in the range of 0.1 mm to 3 mm can be used.
  • Step S120 a series of laser beams for irradiating the glass substrate is adjusted.
  • the series of laser beams may be adjusted by branching one laser beam from the laser light source into a plurality of branch beams using a diffractive optical element or the like. Each branch beam is adjusted to focus on the interior of the glass substrate or the surface of the glass substrate. Note that the focal points are substantially arranged on a straight line.
  • FIG. 3 schematically shows an example of the configuration of an apparatus used when carrying out the method according to the present invention.
  • the apparatus 300 includes a laser beam 320 emitted from a laser light source (not shown), and a diffractive optical element 350 that branches the laser beam 320 into a plurality of branched beams 360A, 360B, and 360C. , And a lens 330 for converging each branch beam 360A, 360B, 360C to a desired position on the glass substrate 310.
  • the laser light source is not particularly limited, but an excimer laser light source (XeCl: wavelength 308 nm, KrF: wavelength 248 nm, ArF: wavelength 193 nm), YAG laser light source (wavelength 1064 nm), YVO4 laser light source (wavelength 1064 nm), titanium sapphire laser light source (Wavelength 800 nm) or a carbon dioxide laser light source (wavelength 10.6 ⁇ m) may be used.
  • These laser light sources may be fundamental wave, second harmonic, or third harmonic laser sources.
  • the YAG laser light source and the YVO4 laser light source may be, for example, a second harmonic wave source or a third harmonic wave laser source in addition to the fundamental wave described above.
  • a second harmonic YAG laser has a wavelength of 532 nm
  • a third harmonic YAG laser has a wavelength of 355 nm.
  • the power of the laser light source is larger because more branched beams can be obtained at one time.
  • the diffractive optical element 350 may be any element as long as it can divide one laser beam into a plurality of branched beams.
  • a beam splitter may be used instead of the diffractive optical element. good.
  • a laser beam 320 is emitted from a laser light source.
  • the laser beam 320 is branched into three or more branched beams 360 (360A, 360B, 360C) in the diffractive optical element 350.
  • the branched beams 360A, 360B, and 360C are converged by the lens 330 to form focal points 370A, 370B, and 370C on the inside or the surface of the glass substrate 310, respectively.
  • Each focal point 370A, 370B, 370C is arranged in a straight line.
  • the diffractive optical element 350 divides one laser beam 320 into three branched beams 360A, 360B, and 360C.
  • the diffractive optical element 350 may split one laser beam 320 into four or more branched beams.
  • the divided branched beams 360 ⁇ / b> A, 360 ⁇ / b> B, 360 ⁇ / b> C are collected by a single lens 330.
  • a plurality of lenses may be used to converge each branch beam.
  • the spot diameters of the focal points 370A, 370B, and 370C vary depending on the performance of the lens 330 and the like, but may be, for example, about 0.1 ⁇ m to 100 ⁇ m.
  • the distance between the focal points 370A, 370B, and 370C is not particularly limited. However, due to restrictions on the configuration of the apparatus, the realistic distance may be in the range of about 20 ⁇ m to 400 ⁇ m, and may be in the range of about 50 ⁇ m to 250 ⁇ m. preferable.
  • Step S130 the intensity of each split beam 360A, 360B, 360C is controlled.
  • the intensity of each split beam 360A, 360B, 360C is not controlled equally, but each branch beam 360A, 360B, 360C is the branch beam 360A, 360C on the end side.
  • the intensity of the branched beam 360B on the non-end side is adjusted to be small.
  • the temperature distribution due to the heat input of the branched beam becomes substantially uniform. That is, when the intensities of the branched beams 360A, 360B, and 360C are substantially equal, the focal point 370B of the glass substrate 310 is compared with the focal points 370A and 370C at both ends due to heat diffusion from the focal points 370A and 370C at both ends. Temperature rises. As a result, the retardation distribution finally obtained has a distribution in which the central portion becomes large.
  • the intensity of the non-end-side branch beam 360B is controlled to be smaller than that of the end-side branch beams 360A and 360C.
  • the non-end-side branch beam 360B is controlled to have an intensity of 20% to 60% of the intensity of the end-side branch beams 360A and 360C.
  • the intensity adjustment of each branch beam is preferably performed in the above-described diffractive optical element 350.
  • the optical system is not complicated and the strength can be adjusted with high accuracy.
  • the intensity of each branch beam may be adjusted using an ND filter or the like.
  • the intensity of the branch beams 360A and 370C forming the focal points 370A and 370C at both ends is, for example, in the range of 1 W to 10 W.
  • Step S140 Next, the branched beams 360A, 360B, and 360C controlled as described above are simultaneously irradiated onto the glass substrate 310. Further, as shown in FIG. 3, the branched beams 360A, 360B, and 360C are scanned in a predetermined direction (Y direction in the example of FIG. 3) with respect to the glass substrate 310.
  • the scanning speed of each of the branched beams 360A, 360B, and 360C varies depending on the distance between the focal points 370A, 370B, and 370C, but is, for example, in the range of 0.1 mm / second to 50 mm / second.
  • the heat input between the focal points 370A to 370C is almost the same.
  • the region between the focal points 370A to 370C is subjected to substantially the same thermal history during the scanning of the branched beams 360A, 360B, and 360C. Therefore, a birefringent region having a relatively uniform retardation distribution is formed on the glass substrate 310 by scanning each of the branched beams 360A, 360B, and 360C.
  • the thickness of the birefringent region depends on the scanning speed, but may be, for example, about 50 ⁇ m to 200 ⁇ m.
  • a retardation distribution within ⁇ 10% is obtained in a region of at least 300 ⁇ m along the X direction.
  • the retardation plate obtained by such a method has an internal transmittance of 98% or more with respect to visible light.
  • step S120 to step S140 described above may be repeated as necessary.
  • a birefringence region having a width of about 300 ⁇ m is formed by irradiation with each of the branched beams 360A, 360B, and 360C having a focal distance of 100 ⁇ m (the heat spread on both ends is set to 50 ⁇ m)
  • the method according to the invention provides a birefringent region having a width in the range of 300 ⁇ m to 50 mm, for example.
  • step S140 after the birefringence region is formed by irradiation with the branched beams 360A, 360B, and 360C, the focus position of the series of laser beams is shifted by about 150 ⁇ m in the Z direction in FIG.
  • two layers of birefringent regions can be formed in the thickness direction of the substrate.
  • a retardation twice as large as that of a single layer for example, 100 nm
  • five layers of retardation can be obtained compared to one layer by using five layers.
  • steps S120 to S140 may be repeated by moving the focus position of the series of laser beams in the X direction and the Z direction in FIG. In this case, expansion of the birefringence region width and high retardation can be obtained.
  • FIG. 4 schematically shows another configuration example of an apparatus used when performing the method according to the present invention.
  • the apparatus 400 has a configuration substantially similar to that of the apparatus 300 shown in FIG. However, the apparatus 400 is irradiated with a branched beam from both sides of the glass substrate 410. That is, the apparatus 400 includes the diffractive optical element 450-1 and the lens 430-1 so that one or more branched beams can be irradiated from the upper surface side of the glass substrate 410. In addition, the apparatus 400 includes a diffractive optical element 450-2 and a lens 430-2 so that one or more branched beams can be irradiated from the lower surface side of the glass substrate 410.
  • a laser beam 420-1 is emitted from a laser light source (not shown).
  • the laser beam 420-1 is branched into two branched beams 460A and 460C in the diffractive optical element 450-1.
  • a laser beam 420-2 is emitted from a laser light source (not shown).
  • the laser beam 420-2 is branched into two branched beams 460B and 460D in the diffractive optical element 450-2.
  • the branched beams 460A and 460C are converged by the lens 430-1 and irradiated on the inside or the surface of the glass substrate 410 from the upper side of the glass substrate 410. Thereby, the focal points 470A and 470C are formed.
  • the branched beams 460B and 460D are converged by the lens 430-2 and irradiated on the inside or the surface of the glass substrate 410 from the lower side of the glass substrate 410.
  • the focal points 470B and 470D are formed.
  • the focal points 470A to 470D are arranged linearly.
  • each of the branched beams 460A to 460D prepared in this way is controlled.
  • each of the branched beams 460A to 460D is adjusted so that the intensity of the non-end-side branch beams 460B and 460C is smaller than that of the end-side branch beams 460A and 460D. Therefore, when the glass substrate 410 is irradiated and scanned with a series of laser beams 460A to 460D, the regions between the focal points 470A to 470D receive substantially the same thermal history.
  • the branched beams 460A to 460D are scanned on the glass substrate 410, whereby a relatively uniform birefringence region is formed on the glass substrate 410.
  • the diffractive optical element 450-1 splits one laser beam 420-1 (420-1) into two branched beams 460A and 460C (460B and 460D). Yes.
  • the diffractive optical element 450-1 (450-2) may divide one laser beam 420-1 (420-2) into one, or three or more branched beams.
  • an odd-numbered branch beam (460A, 460C) is irradiated from the upper side of the glass substrate 410 from the left end
  • an even-numbered branch beam ( 460B, 460D) is irradiated from the lower side of the glass substrate 410.
  • the branched beam irradiated from each side of the glass substrate 410 may be any of a series of laser beams.
  • an even-numbered branch beam (460B, 460D) is irradiated from the upper side of the glass substrate 410 and an odd-numbered branch beam (460A, 460C) is irradiated from the lower side of the glass substrate 410 from the left end.
  • an even-numbered branch beam (460B, 460D) is irradiated from the upper side of the glass substrate 410 and an odd-numbered branch beam (460A, 460C) is irradiated from the lower side of the glass substrate 410 from the left end.
  • several branched beams (for example, branched beams 460A, 460B, and 460C) continuous from the left end are irradiated from the upper side of the glass substrate 410, and the remaining branched beams (460D) are irradiated under the glass substrate 410. You may irradiate from the side.
  • the method for producing the retardation plate by forming the birefringent region in the glass substrate has been described.
  • the birefringent region has a continuous length along the scanning direction of a series of laser beams.
  • the form of the birefringent region obtained by the present invention is not limited to this.
  • the birefringent region obtained by the method according to the present invention may be configured to have non-birefringent regions periodically along the scanning direction of a series of laser beams.
  • step S140 when a series of laser beams are irradiated onto the glass substrates 310 and 410 and scanned, the series of laser beams may be turned on / off at a predetermined timing. good. Thereby, the periodic structure of an irradiation part (birefringence area
  • step S140 when a series of laser beams are irradiated onto the glass substrates 310 and 410 and scanned, output modulation as shown in FIG. 6A may be performed on the series of laser beams.
  • the periodic structure of the irradiation part (birefringence area) / non-irradiation part (non-birefringence area) can be obtained along the scanning direction of a series of laser beams, and further, the irradiation part as shown in FIG. 6B
  • a retardation plate having a more uniform retardation distribution along the scanning direction of the (birefringent region) can be obtained.
  • a step of installing a mask on the surfaces of the glass substrates 310 and 410 may be added before the above-described step S140.
  • the periodic structure of the irradiation part (birefringence region) / non-irradiation part (non-birefringence region) can be obtained along the scanning direction of a series of laser beams.
  • the transmittance of the light transmission region of the mask may vary depending on the location. Thereby, the same effect as when the output of a series of laser beams is modulated can be obtained. Therefore, also in this case, a retardation plate having a more uniform retardation distribution along the scanning direction of the irradiation part (birefringent region) can be obtained.
  • the obtained periodic structure of the irradiated part (birefringent region) / non-irradiated part (non-birefringent region) may be cut in a direction perpendicular to the scanning direction and / or in a parallel direction. That is, a small phase difference plate can be obtained by cutting the glass substrate between non-irradiated portions (non-birefringent regions) and separating the birefringent regions.
  • Such a small retardation plate is significant because the periphery is covered with a non-birefringence region even after cutting. That is, in a normal case, when a retardation plate having a birefringent region continuously formed along the scanning direction is cut into small pieces, the birefringent region is exposed on the cut surface. In this case, the tensile residual stress introduced is released on the exposed surface of the birefringent region, and there is a problem that an appropriate birefringent region does not exist in the glass substrate.
  • the method according to the present invention can also be applied to a broadband wave plate.
  • the broadband wave plate is configured by laminating a plurality of wave plates so that the directions of birefringence axes intersect.
  • the above-described steps S120 to S140 are performed at the first depth of the glass substrate, and the first compound along the first scanning direction of the series of laser beams is performed.
  • a birefringent region having a refractive axis is formed.
  • the above-described steps S120 to S140 are performed in the second scanning direction that intersects the first birefringence axis by changing the scanning direction of the series of laser beams. carry out.
  • two birefringent regions having birefringent axes intersecting each other can be formed in the glass substrate.
  • FIG. 7 schematically shows a top view of the retardation film according to the present invention.
  • FIG. 8 schematically shows a cross-sectional view taken along the line AA of the retardation plate of FIG.
  • the retardation film 100 includes a birefringent region extending along a XY plane on a part of a glass substrate 110 having first surfaces 112A and 112B parallel to each other. 150.
  • the birefringent region 150 has a substantially rectangular parallelepiped shape, is parallel to the first surface 112A (and the second surface 112B) of the glass substrate 110, has a length L extending along the Y direction, and a X direction. It has a width W extending along it and a thickness D.
  • the birefringent region 150 is formed inside the glass substrate 110.
  • the birefringent region 150 is the first surface 112A or the first surface of the glass substrate 110. It may be formed on the surface of the second surface 112B.
  • the retardation distribution of the birefringent region 150 is relatively uniform. Therefore, in the birefringent region 150 of the retardation plate 100 according to the present invention, a region of at least 300 ⁇ m along the scanning direction of the birefringent region 150 (Y direction in FIG. 7) and the width direction of the birefringent region 150 (FIG. 7). In the region of at least 300 ⁇ m along the X direction, a retardation distribution within ⁇ 10% (for example, within ⁇ 5%) is obtained.
  • the retardation plate 100 according to the present invention is characterized by having an internal transmittance of 98% or more with respect to visible light.
  • the periphery of the retardation film 100 shown in FIGS. 7 and 8 is covered with a non-birefringent region 170. Therefore, in the retardation film 100, as described above, it is possible to maintain an appropriate birefringence state without releasing the residual tensile stress.
  • FIG. 9 shows a top view of the glass substrate 200 including the retardation plate shown in FIGS.
  • FIG. 10 is a cross-sectional view of the glass substrate 200 taken along the line BB in FIG. 9 and 10, the scale is not shown, and it should be noted that these figures are different in scale from those in FIGS. 7 and 8.
  • the glass substrate 200 has an upper surface 212A and a lower surface 212B. Moreover, the glass substrate 200 has the periodic structure 255 of the birefringent area
  • the glass substrate 200 having such a periodic structure 255 can be manufactured by repeatedly turning on / off the series of laser beams when irradiating and scanning the series of laser beams onto the glass substrate. .
  • it can be manufactured by placing a mask on the glass substrate before irradiating and scanning the glass substrate with a series of laser beams.
  • the glass substrate 200 is cut along the lines C1 to C7 in FIG. 9, that is, at the portion of the non-birefringence region 270.
  • the periodic structure 255 is separated.
  • the phase difference plate 100 as shown in FIGS. 7 and 8 having the birefringent region 250 whose periphery is covered with the non-birefringent region 270 can be obtained.
  • Example 1 A quarter-wave plate was prototyped using the apparatus shown in FIG. 3 according to the following procedure.
  • a glass substrate (crown glass) having a thickness of 0.6 mm was prepared.
  • a laser light source AVIA-X manufactured by Coherent having a wavelength of 355 nm was used.
  • the output of the laser is 9W.
  • the laser beam was branched into three branched beams by a diffractive optical element. Each branch beam was condensed in a glass substrate by a lens (theoretical spot diameter 0.5 [mu] m).
  • the focal points of the branched beams were linearly arranged in the glass substrate, and the distance between the focal points in the glass substrate was 150 ⁇ m.
  • the intensity of the central branch beam was 40% of the intensity of the branch beams at both ends.
  • the three branched beams were scanned in the same direction to form a birefringent region in the glass substrate.
  • the scanning speed was 2 mm / second.
  • the full length (length in the direction parallel to the scanning direction) of the birefringent region was 20 mm, and the width (length in the direction perpendicular to the scanning direction) was 400 ⁇ m.
  • the thickness of the birefringent region was about 100 ⁇ m.
  • the retardation value of the obtained birefringent region was 112 nm.
  • Example 2 A birefringent region was formed in the glass substrate by the same method as in Example 1. However, in Example 2, after the processing shown in Example 1, scanning was performed again by changing the depth of focus of a series of laser beams. That is, in Example 2, the focus position was shifted by 150 ⁇ m in the thickness direction of the glass substrate with respect to the focus position of the first series of laser light, and the second scan with the series of laser light was performed. That is, in Example 2, the focus position was shifted by 150 ⁇ m in the thickness direction of the glass substrate with respect to the focus position of the first series of laser light, and the second scan with the series of laser light was performed.
  • the full length (length in the direction parallel to the scanning direction) of the birefringent region was 20 mm, and the width (length in the direction perpendicular to the scanning direction) was 400 ⁇ m.
  • the retardation value of the obtained birefringent region was 195 nm.
  • a glass substrate (soda lime glass) having a thickness of 1 mm was prepared.
  • a laser beam was irradiated from above the glass substrate.
  • AVIA-X manufactured by Coherent having a wavelength of 355 nm was used.
  • the output of the laser beam is 3W.
  • the spot diameter of the focal spot is 0.5 ⁇ m (theoretical value).
  • the laser beam was scanned in a first direction parallel to the glass substrate.
  • the scanning speed was 40 mm / second.
  • the focal point of the laser beam was shifted by 10 ⁇ m in the direction perpendicular to the first direction, and the same scanning was performed. This was repeated 25 times.
  • the focal point of the laser beam was shifted from the focal point of the first laser beam by 200 ⁇ m in the depth direction of the glass substrate, and the laser beam was similarly scanned. Thereafter, the focal point of the laser beam was shifted by 10 ⁇ m in a direction perpendicular to the first direction, and the same scanning was performed. This was repeated 25 times.
  • the focal point of the laser beam was shifted from the initial focal point of the laser beam by 400 ⁇ m in the depth direction of the glass substrate, and the laser beam was similarly scanned.
  • the focal point of the laser beam was shifted by 10 ⁇ m in the direction perpendicular to the first direction, and the same scanning was performed. This was repeated 25 times.
  • a birefringent region having a total length (length in a direction parallel to the scanning direction) of 20 mm and a width (length in a direction perpendicular to the scanning direction) of about 350 ⁇ m was formed in the glass substrate.
  • the retardation value of the obtained birefringent region was 112 nm.
  • Example 2 A birefringent region was formed in the glass substrate by the same method as in Example 1. However, in this comparative example 2, the three branched beams have the same intensity. Other conditions are the same as in the first embodiment. The retardation value of the obtained birefringent region was 89.0 nm.
  • a birefringence imaging system Abrio manufactured by Cri was used for the measurement of retardation.
  • a configuration is used in which a light source and a circular polarization filter are arranged in front of a sample, and an ellipsometer and a CCD camera are arranged behind the sample.
  • the state of the liquid crystal optical element in the ellipsometer is changed, a plurality of images that have passed through the ellipsometer are acquired by a CCD camera, and these images are compared and calculated. Can be quantified.
  • FIG. 11 shows the results obtained with the quarter-wave plate according to Example 1.
  • 12 to 14 show the results obtained for the half-wave plate according to Example 2 and the quarter-wave plate according to Comparative Examples 1 and 2, respectively.
  • Table 1 shows retardation distributions obtained for each quarter-wave plate and half-wave plate.
  • the retardation distribution is a ratio (%) obtained by dividing the difference between the maximum and minimum retardation values in the range of 300 ⁇ m along the width direction of the birefringent region by the average value (retardation average value) of the maximum and minimum values. ) As half of
  • the retardation distribution was ⁇ 4% or less.
  • a periodic change was observed in the retardation distribution. Such periodic changes are undesirable because they induce light diffraction.
  • the retardation distribution was ⁇ 21%, and the retardation distribution was extremely large.
  • the retardation distribution in the range of 300 ⁇ m along the scanning direction of the birefringent region was ⁇ 2% or less in all of Examples 1 and 2 and Comparative Examples 1 and 2, and was extremely uniform.
  • the transmittance was measured with a Photo Spectrometer manufactured by Otsuka Electronics.
  • the internal transmittance is shown normalized to a glass substrate having the same composition and the same thickness and not forming a birefringent region.
  • the internal transmittance exceeds 98%.
  • the plate was found to show good transmission.
  • the internal transmittance is 70% and 90%, respectively, and the internal transmittance may be significantly lowered by the formation of the birefringent region. all right.
  • Wavefront aberration was measured using each 1/4 and 1/2 wavelength plate. Wavefront aberration was measured using a Fizeau phase shift interferometer (Zygo).
  • the wavefront aberration is 10 m ⁇ , and these quarter wavelength plate and half wavelength are The plate was found to have suppressed wavefront aberration.
  • the wavefront aberrations were 25.4 m ⁇ and 50 m ⁇ , respectively, and it was found that the wavefront aberration was significantly increased by forming the birefringent region. .
  • the retardation distribution was significantly suppressed in the quarter-wave plate and the half-wave plate manufactured by the method according to the present invention.
  • the quarter wavelength plate and the half wavelength plate manufactured by the method according to the present invention have little decrease in transmittance with respect to visible light, and the wavefront aberration is significantly suppressed.
  • the present invention can be applied to optical components such as a half-wave plate, a quarter-wave plate, an optical pickup element, and an isolator.

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Abstract

L'invention concerne un procédé de fabrication d'une plaque à différence de phase selon lequel la distribution du ralentissement est considérablement améliorée et où la transmissibilité et l'aberration du front d'onde pour la lumière visible sont améliorées. Le procédé comprend les étapes suivantes : (a) préparation d'un substrat en verre ayant une première et une deuxième surfaces ; (b) réglage d'une série de lasers séparés en trois faisceaux ou plus de telle sorte que le foyer de chaque faisceau séparé peut être positionné de manière linéaire soit à l'intérieur du substrat en verre, soit sur le substrat en verre ; (c) commande des intensités des séries de lasers de telle sorte que l'intensité d'un faisceau séparé qui n'atteint pas les deux côtés finaux est inférieure à l'intensité d'un faisceau qui atteint les deux côtés finaux ; et (d) projection simultanée des séries de lasers soit à l'intérieur du substrat en verre, soit sur le substrat en verre et balayage de la première ou de la deuxième surface dans une direction parallèle, formant ainsi une zone de biréfringence dans le substrat en verre.
PCT/JP2011/067695 2010-08-20 2011-08-02 Procédé de fabrication de plaque à différence de phase et plaque à différence de phase WO2012023429A1 (fr)

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JP2010185443A JP2013224974A (ja) 2010-08-20 2010-08-20 位相差板の製造方法および位相差板
JP2010-185443 2010-08-20

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JP7007656B2 (ja) * 2020-10-16 2022-01-24 国立大学法人埼玉大学 剥離基板製造方法
US11880061B2 (en) * 2021-10-16 2024-01-23 ZSquare Ltd. Optical fiber from a single polymer

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004196585A (ja) * 2002-12-18 2004-07-15 Nippon Sheet Glass Co Ltd レーザビームにより材料内部に異質相を形成する方法、構造物および光部品
WO2008126828A1 (fr) * 2007-04-09 2008-10-23 Asahi Glass Company, Limited Plaque de différence de phase et son procédé de fabrication

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004196585A (ja) * 2002-12-18 2004-07-15 Nippon Sheet Glass Co Ltd レーザビームにより材料内部に異質相を形成する方法、構造物および光部品
WO2008126828A1 (fr) * 2007-04-09 2008-10-23 Asahi Glass Company, Limited Plaque de différence de phase et son procédé de fabrication

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