WO2020079774A1 - Dispositif de source de lumière laser - Google Patents

Dispositif de source de lumière laser Download PDF

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Publication number
WO2020079774A1
WO2020079774A1 PCT/JP2018/038654 JP2018038654W WO2020079774A1 WO 2020079774 A1 WO2020079774 A1 WO 2020079774A1 JP 2018038654 W JP2018038654 W JP 2018038654W WO 2020079774 A1 WO2020079774 A1 WO 2020079774A1
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Prior art keywords
polarization
laser
laser light
semiconductor laser
polarization rotation
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PCT/JP2018/038654
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English (en)
Japanese (ja)
Inventor
博 木田
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三菱電機株式会社
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2018/038654 priority Critical patent/WO2020079774A1/fr
Priority to PCT/JP2019/039824 priority patent/WO2020080220A1/fr
Priority to JP2020553114A priority patent/JPWO2020080220A1/ja
Publication of WO2020079774A1 publication Critical patent/WO2020079774A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/022—Mountings; Housings

Definitions

  • the present invention relates to a laser light source device.
  • the semiconductor laser element emits laser light with low power consumption and excellent monochromaticity and high directivity.
  • a semiconductor laser device having such features is expected as a replacement light source for currently popular lamps.
  • a semiconductor laser device has been attracting attention as a light source of a projection type display device such as a projector.
  • the semiconductor laser element When the semiconductor laser element is mounted as a light source in a projection type display device, the semiconductor laser element has a small light emitting area, and therefore, in the optical design thereof, it is possible to miniaturize the optical element necessary for spatial composition of laser beams.
  • miniaturization of optical elements enables miniaturization of display devices such as digital mirror devices (DMD (Digital Mirror Device)) and liquid crystal displays (LCD (Liquid Crystal Display)), resulting in lower system cost. To do.
  • DMD Digital Mirror Device
  • LCD Liquid Crystal Display
  • the light source of the projection display device is composed of a plurality of semiconductor laser elements.
  • the laser light emitted from the semiconductor laser device is composed of waves with the same phase. This feature produces the monochromaticity and high directivity of the semiconductor laser.
  • a striped pattern or speckles are generated due to the coherence of the waves. Speckle is a particle-like pattern due to the coherence of random waves appearing by the laser light irradiated on the screen.
  • Such an interference pattern has been one of the causes of deterioration of image quality when a laser is used as a light source of a projection display device.
  • a means for mixing semiconductor laser light of multiple wavelengths or a means for disturbing the polarization uniformity of the semiconductor laser light is effective.
  • a laser light source device that rotates the polarization of laser light emitted from one or a plurality of light emitting points of a laser light source by 90 ° by a polarization rotation unit arranged on the optical axis thereof.
  • the laser light source device is an array type laser light source in which a plurality of laser beams oscillates from one semiconductor laser chip.
  • Patent Document 1 can reduce interference fringes and speckles, since it is an array type laser light source, the gain is reduced due to the temperature rise due to heat generated from an adjacent laser, and a sufficient output is obtained. Can't get
  • the present invention has been made to solve the above problems, and an object of the present invention is to provide a laser light source device capable of reducing the occurrence of interference fringes and speckles and reducing the temperature rise due to laser oscillation. To do.
  • the laser light source device includes a base, a plurality of semiconductor laser elements each of which is individually held on the upper surface of the base and emits a plurality of laser lights whose polarization directions are aligned in one direction.
  • a polarization conversion unit that rotates the polarization direction of at least a part of the laser light to disturb the polarization directions of the plurality of laser lights so that they are not aligned in one direction.
  • the polarization conversion unit includes a plurality of polarization rotation elements that convert the polarization of the plurality of laser lights into circularly polarized light.
  • the plurality of polarization rotation elements are selectively arranged in correspondence with the semiconductor laser element that emits a part of the laser light among the plurality of semiconductor laser elements, and convert the polarization of a part of the laser light into left-handed circularly polarized light.
  • the first polarization rotation element and the other semiconductor laser element which emits another part of the laser light among the plurality of semiconductor laser elements are selectively arranged to correspond to the polarization of another part of the laser light.
  • a second polarization rotation element that converts the light into right-handed circularly polarized light.
  • the present invention it is possible to provide a laser light source device that reduces the occurrence of interference fringes and speckles, and reduces the temperature rise due to laser oscillation.
  • FIG. 3 is a perspective view showing a configuration of a laser light source device and laser light emitted from the laser light source device according to the embodiment. It is an exploded perspective view showing the composition of the laser light source device in an embodiment. It is a figure which shows the structure of the polarization rotation element in embodiment. It is a figure which shows the structure of the polarization rotation element in embodiment.
  • FIG. 3 is a perspective view showing a detailed configuration of the semiconductor laser device according to the embodiment.
  • FIG. 3 is a perspective view showing configurations of a base and a semiconductor laser device according to the embodiment.
  • FIG. 7 is a cross-sectional view taken along the line A-A ′ shown in FIG. 6. It is a figure explaining operation
  • FIG. 3 is a perspective view showing a configuration of a spacer and a lens in the embodiment.
  • FIG. 13 is a sectional view taken along line B-B ′ shown in FIG. 12.
  • FIG. 8 is a diagram showing a configuration of a spacer and a polarization rotation element of a laser light source device according to Modification 1 of the embodiment.
  • FIG. 9 is a diagram showing a polarization element substrate including a polarization rotation element according to Modification 1 of the embodiment. It is a figure which shows the structure of the spacer and polarization rotation element of the laser light source device in the modification 2 of embodiment. It is a figure which shows the polarization element substrate containing the polarization rotation element in the modification 2 of embodiment.
  • FIG. 1 is a perspective view showing a configuration of a laser light source device 1 according to the embodiment and laser light emitted from the laser light source device 1.
  • FIG. 2 is an exploded perspective view showing the configuration of the laser light source device 1.
  • the laser light source device 1 is composed of a base 30, semiconductor laser elements 101 to 104, lenses 41 to 44, a spacer 20, and polarization rotation elements 51 to 54.
  • the base 30 supports the semiconductor laser elements 101 to 104 on the upper surface 30A.
  • the base 30 has a flat surface on the upper surface 30A, and the semiconductor laser elements 101 to 104 are fixed to the flat surface.
  • the base 30 is, for example, a flat plate.
  • the base 30 is provided with slots 31 to 34.
  • the slots 31 to 34 are here through holes.
  • the long holes 31 to 34 are holes into which the two lead pins 14 of each of the semiconductor laser devices 101 to 104 are inserted.
  • a current is supplied to each semiconductor laser element via the lead pin 14.
  • the x-, y-, and z-axes shown in each figure form a rectangular coordinate system.
  • the x-axis and the y-axis are parallel to the upper surface 30A of the base 30, and the z-axis points above the base 30.
  • Each of the semiconductor laser elements 101 to 104 is an element on which a semiconductor laser chip that oscillates one laser beam is mounted.
  • Each of the semiconductor laser devices 101 to 104 is individually held on the upper surface 30A of the base 30.
  • each semiconductor laser element is fixed to a plane formed on the upper surface 30A of the base 30.
  • Each semiconductor laser element emits laser light upward with respect to the base 30.
  • the semiconductor laser chip may be configured by dividing the oscillator into two or three parts in order to improve efficiency.
  • the semiconductor laser devices 101 to 104 emit laser beams 71 to 74 whose polarization directions are aligned in one direction.
  • the polarization of the laser beams 71 to 74 emitted from the semiconductor laser devices 101 to 104 is parallel to the y-axis direction (not shown).
  • the semiconductor laser elements 101 to 104 emit laser beams 71 to 74 having a cross-sectional shape with a wide width in the x-axis direction in parallel with the z-axis direction.
  • the spacer 20 is provided to cover the semiconductor laser elements 101 to 104 from above.
  • the spacer 20 holds the lenses 41 to 44, which will be described later, and has a function of keeping the distance between each lens and each semiconductor laser element constant.
  • the spacer 20 has spacer windows 21 to 24 on the upper surface.
  • the outer shapes of the spacer windows 21 to 24 have a square shape.
  • the spacer 20 has spacer step portions 25 to 28 provided on the outer peripheries of the spacer window portions 21 to 24, respectively.
  • a polarization rotation element can be installed at each spacer step. Laser beams 71 to 74 emitted from the semiconductor laser devices 101 to 104 respectively pass through the spacer windows 21 to 24. That is, the spacer includes a frame structure including the spacer window portions 21 to 24 and the spacer step portions 25 to 28 at positions where the plurality of laser beams 71 to 74 pass. Each frame structure holds each of the plurality of polarization rotation elements.
  • the spacer 20 may be fastened and fixed to the upper surface 30A of the base 30 with a screw, or may be fixed with an adhesive. Alternatively, the spacer 20 may be fixed by both.
  • the spacer 20 is manufactured by die casting of zinc, aluminum, or the like in consideration of formability. However, since the spacer 20 is not required to have a thermal effect, the spacer 20 may be made of a resin material.
  • the polarization rotation elements 51 to 54 form a polarization conversion unit.
  • the polarization converter rotates the polarization direction of at least a part of the laser lights 71 to 74, and disturbs the polarization directions of the laser lights 71 to 74 so that they are not aligned in one direction.
  • the polarization rotation elements 51 and 53 convert the polarization direction of a part of the laser light 71 to 73 out of the laser light 71 to 74 into left-handed circularly polarized light 91 and 93.
  • the polarization rotation elements 51 and 53 are selectively arranged corresponding to the semiconductor laser elements 101 and 103 that emit a part of the laser beams 71 and 73 among the semiconductor laser elements 101 to 104.
  • the polarization rotation elements 52 and 54 convert the polarization direction of another part of the laser light 72 to 74 out of the laser light 71 to 74 into circularly polarized light 92 and 94 of right rotation.
  • the polarization rotation elements 52 and 54 are selectively arranged corresponding to the other semiconductor laser elements 102 and 104 that emit the other part of the laser beams 72 and 74 of the semiconductor laser elements 101 to 104.
  • FIG. 3 is a diagram showing the configuration of the polarization rotation elements 51 and 53.
  • FIG. 4 is a diagram showing the configuration of the polarization rotation elements 52 and 54.
  • the polarization rotation elements 51 to 54 have a fast axis (F axis) 50A in a direction having a low refractive index and a slow axis (S axis) 50B in a direction having a high refractive index.
  • the polarization rotation elements 51 to 54 are plate-shaped elements having a plane parallel to the FS plane in which the fast axis (F axis) 50A and the slow axis (S axis) 50B are orthogonal to each other.
  • the polarization rotation elements 51 to 54 are quarter-wave plates. The quarter-wave plate delays those components in the slow axis direction by a quarter wavelength with respect to the components of the laser beams 71 to 74 in the fast axis direction.
  • the polarization rotation elements 51 and 53 are arranged such that the fast axis 50A forms an angle of ⁇ 45 ° and the slow axis 50B forms an angle of 45 ° with respect to the polarization directions of the laser beams 71 and 73 emitted from the semiconductor laser elements 101 and 103.
  • the polarization of the laser beams 71 and 73 emitted from the semiconductor laser elements 101 and 103 is linearly polarized light parallel to the y-axis. Therefore, the fast axis 50A forms an angle of ⁇ 45 ° with the y axis, and the slow axis 50B forms an angle of 45 ° with the y axis (see FIGS. 2 and 3).
  • the polarization rotation elements 52 and 54 make an angle of 45 ° with respect to the fast axis 50A and ⁇ 45 ° with respect to the slow axis 50B with respect to the polarization directions of the laser beams 72 and 74 emitted from the semiconductor laser elements 102 and 104.
  • the fast axis 50A forms an angle of 45 ° with the y-axis
  • the slow axis 50B forms an angle of ⁇ 45 ° with respect to the y-axis (see FIGS. 2 and 4).
  • the outer shapes of the polarization rotation elements 51 to 54 have square shapes similar to the outer shapes of the spacer step portions 25 to 28, as shown in FIG.
  • the square consists of sides parallel to the x-axis or the y-axis.
  • the fast axis 50A and the slow axis 50B of the polarization rotation elements 51 to 54 coincide with the diagonal direction of the square.
  • the polarization rotation elements 51 to 54 are held by the spacer step portions 25 to 28, respectively.
  • the polarization rotators 51 and 53 are selectively arranged corresponding to the semiconductor laser devices 101 and 103 by being housed in the spacer step portions 25 and 27.
  • the polarization rotation elements 52 and 54 are selectively arranged corresponding to the other semiconductor laser elements 102 and 104 by being housed in the spacer step portions 26 and 28.
  • the polarization rotation elements 51 to 54 are arranged on the upper surface side of the spacer 20, but the polarization rotation elements 51 to 54 may be arranged on the bottom surface side of the spacer 20. In that case, the polarization rotation element is fixed to, for example, a spacer step portion provided on the back surface of the spacer 20 with an adhesive or a holding member.
  • the shape of the polarization rotation element may be rectangular, circular, elliptical, or the like as long as it covers the laser beams 71 to 74 of the semiconductor laser elements 101 to 104.
  • the lenses 41 to 44 focus the laser beams 71 to 74.
  • the laser beams 71 to 74 transmitted through the lenses 41 to 44 respectively travel in a direction parallel to the z axis.
  • the lenses 41 to 44 are held by the spacer 20.
  • the lenses 41 to 44 are arranged so as to cover the spacer window portions 21 to 24, respectively.
  • FIG. 5 is a perspective view showing a detailed configuration of the semiconductor laser device 101.
  • the semiconductor laser device 101 has a structure in which a semiconductor laser chip is included in a TO-Can type package.
  • the TO-Can type semiconductor laser device 101 mainly includes a cap 11, a glass window 12, a stem 13, a lead pin 14, and a semiconductor laser chip (not shown).
  • the cap 11 is provided above the stem 13.
  • the glass window 12 is provided on the upper surface of the cap 11.
  • the lead pin 14 is provided below the stem 13.
  • the semiconductor laser chip is arranged inside the cap 11.
  • the semiconductor laser chip has a main optical axis in a direction perpendicular to the stem 13. That is, the semiconductor laser chip emits laser light 71 in the z-axis direction. Generally, when moisture or dust in the air adheres to the end surface of the semiconductor laser chip, the semiconductor laser chip is easily destroyed. However, in the TO-Can type package, the semiconductor laser chip is sealed by the cap 11. Therefore, the airtightness inside the cap 11 is maintained, and the conditions required for the driving environment of the semiconductor laser chip are relaxed. Further, the TO-Can type package element is small. Therefore, it is easy to adjust the number of pieces used, that is, to scale the optical output according to the required specifications.
  • a high-power edge-emitting laser chip is used as the light source of the projection display device.
  • the main material of the semiconductor laser chip is a compound semiconductor such as GaAs or GaN.
  • the active layer of the semiconductor laser chip is formed by epitaxial growth.
  • the epitaxial growth direction corresponds to the x-axis direction
  • the horizontal direction of the active layer corresponds to the y-axis direction.
  • the laser light 71 is emitted from the chip end face located in the direction (z-axis direction) orthogonal to the epitaxial growth direction (x-axis direction).
  • the laser light 71 is emitted from an emission bright point of about 1 ⁇ m in the vertical direction (x-axis direction) of the active layer and several tens to several hundreds of ⁇ m in the horizontal direction (y-axis direction) of the active layer on the end face of the chip. Since the emission port in the vertical direction (x-axis direction) of the active layer is very small, the laser light 71 spreads in the x-axis direction due to the diffraction effect. The spread of the laser beam in the x-axis direction is about 60 ° in all angles. The spread of laser light in the vertical direction (x-axis direction) of the active layer is about 10 times larger than the spread of laser light in the horizontal direction (y-axis direction) of the active layer. Therefore, the cross section of the laser light 71, that is, the far-field pattern has an elliptical shape, as shown in FIG.
  • the arrangement direction of the two lead pins 14 is the same as the horizontal direction (y-axis direction) of the active layer of the semiconductor laser chip. Therefore, the laser light 71 has a small spread in the arrangement direction of the lead pins 14 and a large spread in the x-axis direction orthogonal thereto.
  • the polarization of the laser light 71 emitted from the semiconductor laser device 101 having the above configuration is parallel to the direction horizontal to the active layer (y-axis direction). That is, the semiconductor laser device 101 emits linearly polarized light whose electric field oscillates in the horizontal direction (y-axis direction) of the active layer. However, the laser light may be polarized in the vertical direction (x-axis direction) of the active layer depending on the atomic arrangement of the active layer.
  • FIG. 6 is a perspective view showing the configurations of the base 30 and the semiconductor laser devices 101 to 104.
  • FIG. 7 is a cross-sectional view taken along the line A-A ′ shown in FIG.
  • the base 30 is composed of a member having high thermal conductivity.
  • the base 30 includes a metal material such as Cu and Al.
  • the base 30 includes a ceramic having a high thermal conductivity such as SiC or AlN.
  • a fin for improving the heat capacity and the heat radiation area of the stem 13 or a cooling member connected to a heat pipe in which a coolant such as water is sealed may be added to the stem 13.
  • each semiconductor laser element 101 to 104 are fixed in close contact with the flat surface formed on the upper surface 30A of the base 30 via a highly heat-conductive grease or sheet-shaped heat dissipation material.
  • each semiconductor laser element is preferably soldered to the base 30 with a solder material.
  • the solder material contains, for example, SuAgCu, AuSn or the like as a main component.
  • the base 30 is a flat plate, but the base 30 is not limited thereto, and the surface that contacts the stem 13 may be a flat surface.
  • the base 30 may be provided with a spot facing matching the shape of the stem 13.
  • the elongated holes 31 to 34 have a hole shape so that the lead pin 14 and the base 30 do not come into contact with each other, and are arranged so that the lead pin 14 and the base 30 do not come into contact with each other.
  • the base 30 may have a round hole that can avoid contact between the lead pin 14 and the base 30, instead of the elongated holes 31 to 34.
  • the base 30 has, instead of the elongated holes 31 to 34, a groove structure capable of avoiding the contact between the lead pin 14 and the base 30 and ensuring a wiring path for supplying a current to the semiconductor laser elements 101 to 104. May be.
  • the polarization rotation elements 51 to 54 are made of, for example, an inorganic material or a resin material having birefringence.
  • the inorganic material having birefringence is, for example, crystal.
  • the birefringent resin material is, for example, a resin containing polycarbonate as a base material and is stretched in one direction.
  • the polarization rotation elements 51 and 53 are quarter wave plates. As shown in FIG. 8, when the counterclockwise angle is in the positive direction, the fast axis (F axis) forms an angle of 45 ° with the y axis, and the slow axis (S axis) ⁇ with respect to the y axis. Make an angle of 45 °.
  • the propagation of the light beam in the slow axis (S-axis) direction is different from the propagation of the light beam in the fast axis (F-axis) direction. Be late.
  • the propagation delay in the slow axis direction relative to the fast axis direction is designed to be 1/4 wavelength. Only the electric field in the slow axis direction propagates with a delay of 1 ⁇ 4 wavelength, so that the polarization of the laser light transmitted through the polarization rotation elements 51 and 53 changes with the passage of time, as shown in FIG.
  • the polarization directions (electric field vibration directions) at times t0, t1, t2, and t3 are + F, ⁇ S, ⁇ F, and + S directions, respectively.
  • the laser light that has passed through the polarization rotation elements 51 and 53 travels in such a manner that the polarization direction thereof spirals counterclockwise. That is, the polarization rotation elements 51 and 53 convert the polarization direction of the laser light from the linearly polarized light 81 in the y-axis direction to the left-handed circularly polarized light 91 and 93.
  • the polarization rotation elements 52 and 54 are also quarter wave plates. As shown in FIG. 10, the fast axis (F axis) forms an angle of ⁇ 45 ° with the y axis, and the slow axis (S axis) forms an angle of 45 ° with the y axis.
  • F axis fast axis
  • S axis slow axis
  • the polarization directions (vibration directions of the electric field) at times t0, t1, t2, and t3 are + S, ⁇ F, ⁇ S, and + F directions, respectively.
  • the laser light transmitted through the polarization rotation elements 52 and 54 proceeds so that the polarization direction draws a spiral in a clockwise rotation. That is, the polarization rotation elements 52 and 54 convert the polarization direction of the laser light from the linearly polarized light 81 in the y-axis direction into the circularly polarized light 92 and 94 that is rotated clockwise.
  • FIG. 12 is a perspective view showing the configuration of the spacer 20 and the lenses 41 to 44.
  • FIG. 13 is a cross-sectional view taken along line B-B ′ shown in FIG.
  • the laser beams 71 to 74 emitted from the laser light source device 1 are focused on the opening of the optical system of the projection type display device (not shown). Since the distance from the laser light source device 1 to the optical system opening of the projection type display device is not limited, it is preferable that the laser lights 71 to 74 emitted from the laser light source device 1 are parallel lights.
  • each semiconductor laser element emits a spread laser beam.
  • each of the lenses 41 to 44 has a flat surface on the incident surface (a surface in the ⁇ z direction) and an axially symmetric spherical or aspherical convex surface on the output surface (a surface in the + z direction). That is, the lenses 41 to 44 are convex lenses.
  • the incident surfaces of the lenses 41 to 44 do not necessarily have to be flat.
  • Each lens may have a concave surface or a convex surface on the entrance surface or the exit surface as long as it has a function as a convex lens.
  • the surface that may come into contact with the upper surface of the spacer 20 is preferably a flat surface.
  • each lens does not need to be axisymmetric curved surfaces.
  • each lens may be a cylindrical lens having a cylindrical surface on the exit surface or the entrance surface.
  • the cylindrical lens converts the laser light emitted from the semiconductor laser element into parallel light only in the direction having a large divergence angle, that is, in the vertical direction (x-axis direction) with respect to the active layer.
  • the central axes 141 and 144 of the lenses 41 and 44 are arranged so as to coincide with the central axes of the light rays of the semiconductor laser elements 101 and 104, respectively.
  • the lenses 41 and 44 are preferably fixed to the upper surface of the spacer 20 with an adhesive. Note that the lenses 41 and 44 may be fixed to the upper surface of the spacer 20, and the lenses 41 and 44 may be fixed from above by a member that holds each lens down. Although not shown in FIG. 13, the lenses 42 and 43 are also fixed to the upper surface of the spacer 20 like the lenses 41 and 44.
  • the outer shapes of the spacer step portions 25 and 28 are similar to the outer shapes of the polarization rotation elements 51 and 54.
  • the outer shapes of the spacer step portions 25 and 28 are larger than the outer shapes of the polarization rotation elements 51 and 54.
  • the height of the spacer step portions 25 and 28 is larger than the thickness of the polarization rotation elements 51 and 54. Therefore, the polarization rotation elements 51 and 54 are arranged so as to be housed in the space formed by the spacer step portions 25 and 28 and the bottom surfaces of the lenses 41 and 44 without protruding upward from the upper surface of the spacer 20.
  • the outer shapes of the spacer step portions 26 and 27 are similar to the outer shapes of the spacer step portions 25 and 28.
  • the heat generated by driving the semiconductor laser elements 101 to 104 is radiated to the base 30. Since each semiconductor laser element is separated, heat generated in each semiconductor laser element is difficult to be transferred to the semiconductor laser element adjacent thereto. In this way, the laser light source device 1 suppresses the temperature rise of the semiconductor laser element.
  • the polarization directions of the laser beams 71 and 73 emitted from the semiconductor laser elements 101 and 103 are converted into left-handed circularly polarized light 91 and 93 by the polarization rotation elements 51 and 53.
  • the polarization directions of the laser beams 72 and 74 emitted from the semiconductor laser elements 102 and 104 are converted into right-handed circularly polarized light 92 and 94 by the polarization rotation elements 52 and 54.
  • the laser light source device 1 emits left-handed circularly polarized light 91, 93 of laser light 71, 73 and right-handed circularly polarized light of laser light 72, 74.
  • the polarization directions of the laser beams 71 to 74 change temporally.
  • the circularly polarized light 91, 93 has a different rotation direction of polarized light from the circularly polarized light 92, 94.
  • the laser beams 71 to 74 have the same cross-sectional shape (beam profile), but their polarization directions are not aligned in one direction.
  • the laser light source device 1 emits two types of laser light having different polarization directions by rotating the polarization directions of the plurality of laser lights by the polarization rotation elements 51 to 54. Such laser light reduces the generation of interference fringes and speckles.
  • the laser light source device 1 includes a base 30 and a plurality of laser lights each of which is individually held on the upper surface 30A of the base 30 and emits a plurality of laser lights whose polarization directions are aligned in one direction.
  • the polarization conversion unit includes a plurality of polarization rotation elements 51 to 54 that convert the polarization of a plurality of laser lights into circularly polarized light.
  • the plurality of polarization rotation elements 51 to 54 are selectively arranged in correspondence with the semiconductor laser elements 101 and 103 that emit a part of the laser light among the plurality of semiconductor laser elements 101 to 104, respectively, and A first polarization rotator (polarization rotator 51, 54) that converts polarized light into left-handed circularly polarized light, and another one that emits a part of the laser light 72, 74 of the plurality of semiconductor laser elements 101 to 104.
  • a second polarization rotation element (polarization rotation element 52, 54) which is selectively arranged corresponding to the semiconductor laser elements 102, 104 and converts the polarization of another part of the laser light 72, 74 into right-handed circularly polarized light. And, including.
  • the above laser light source device 1 is composed of a plurality of semiconductor laser elements 101 to 104 provided individually on the base 30 having good thermal conductivity. Therefore, the temperature rise due to laser oscillation is reduced, and the gain reduction is suppressed.
  • the laser light source device 1 is unlikely to receive heat generated by the lasers in the central portion from the lasers on both sides, and the gain is unlikely to be greatly reduced. Therefore, a sufficient output can be obtained.
  • the laser light source device 1 also emits two types of circularly polarized laser light whose polarization directions change with time. Since these two types of circularly polarized light are composed of left-handed circularly polarized light 91 and 93 and right-handed circularly polarized light 92 and 94 which proceed while rotating leftward, the two types of polarization directions are continuously matched. There is no such thing.
  • the laser light source device 1 reduces the generation of interference fringes and speckles due to the synthesis of laser light.
  • the projection type display device equipped with the laser light source device 1 does not require a light diffusing element having a high degree of scattering.
  • the laser light source device 1 is mounted on a projection type display device, the generation of interference fringes and speckles is suppressed, so that the image quality is improved and the light output efficiency of the projection type display device itself is also improved.
  • the laser light source device 1 includes a plurality of lenses 41 to 44 provided corresponding to the plurality of semiconductor laser elements 101 to 104, respectively, for converting each of the plurality of laser lights into parallel light. Including further.
  • the spacer 20 is fixed to the base 30 and holds the plurality of lenses 41 to 44.
  • the laser light source device 1 can emit laser beams 71 to 74 with high output and high parallelism.
  • the laser light source device according to the first modification of the embodiment is different from the laser light source device 1 according to the above-described embodiments in the configuration of the spacer and the polarization rotation element.
  • FIG. 14 is a diagram showing a configuration of the spacer 120 and the polarization rotation elements 151 to 154 of the laser light source device according to the first modification of the embodiment.
  • the outer shape of the polarization rotation elements 151 to 154 has a parallelogram shape.
  • the outer shape of the spacer step portions 125 to 128 of the spacer 120 has a parallelogram, which is a similar shape slightly larger than the outer shapes of the polarization rotation elements 151 to 154.
  • the outer shapes of the spacer step portions 126 and 128 have a parallelogram shape in which the outer shapes of the spacer step portions 125 and 127 are rotated by 90 ° in the xy plane.
  • FIG. 15 is a diagram showing a polarization element substrate including polarization rotation elements 151 to 154.
  • the fast axis 50A forms an angle of 45 ° with the y axis
  • the slow axis 50B forms an angle of ⁇ 45 ° with the y axis.
  • the polarization rotation elements 151 to 154 are cut out at a slight angle ⁇ with respect to the x-axis direction.
  • the outer shape of the polarization rotation elements 151 to 154 has a parallelogram shape having one side parallel to the y-axis and the other side having an angle ⁇ with the x-axis. That is, the fast axis 50A of the polarization rotation elements 151 to 154 forms an angle of 45 ° with one side and an angle of 45 ° - ⁇ with respect to the other side intersecting the one side when cut out from the polarization element substrate. .
  • the polarization rotation elements 151 and 153 are arranged on the spacer step portions 125 and 127 while maintaining the directions of the fast axis 50A and the slow axis 50B.
  • the polarization rotation elements 152 and 154 cut out from the polarization element substrate are rotated by 90 ° in the xy plane and arranged on the spacer step portions 126 and 128. Therefore, the fast axis 50A of the polarization rotators 152 and 154 makes an angle of 90 ° with the fast axis 50A of the polarization rotators 151 and 153.
  • the polarization rotation elements 151 and 153 function as left rotation polarization rotation elements
  • the polarization rotation elements 152 and 154 function as right rotation polarization rotation elements.
  • the outer shapes of the spacer step portions 125 to 128 have parallelograms that are similar shapes and are slightly larger than the outer shapes of the polarization rotation elements 151 to 154. Therefore, the polarization rotation elements 151 to 154 are arranged in the spacer step portions 125 to 128 corresponding to the respective shapes, that is, at predetermined positions. The polarization rotation element whose front and back are reversed does not fit into the spacer step portions 125 to 128. Such a spacer 120 limits the arrangement direction of the polarization rotation elements 151 to 154 in the assembly process of the laser light source device and the like.
  • the laser light source device having such a configuration has the same effect as that of the above embodiment. Further, since the shapes of the polarization rotation elements 151 to 154 and the shapes of the spacer step portions 125 to 128 correspond to each other, the arrangement direction of the polarization rotation elements is limited. As a result, in the assembling process of the laser light source device, the assembling direction of the polarization rotation element is designated, and the assembling workability is improved.
  • the laser light source device according to the second modification of the embodiment is different from those of the laser light source device 1 according to the above-described embodiment in the configurations of the spacer and the polarization rotation element.
  • FIG. 16 is a diagram showing a configuration of the spacer 220 and the polarization rotation elements 251 to 254 of the laser light source device according to the second modification of the embodiment.
  • the outer shape of the polarization rotation elements 251 to 254 has a parallelogram shape.
  • the outer shape of the spacer step portions 225 to 228 of the spacer 220 has a parallelogram which is a slightly larger shape than the outer shapes of the polarization rotation elements 251 to 254.
  • the outer shapes of the spacer step portions 226 and 228 have a parallelogram shape in which the outer shapes of the spacer step portions 225 and 227 are inverted with respect to the y axis.
  • FIG. 17 is a diagram showing a polarization element substrate including polarization rotation elements 251 to 254.
  • the fast axis 50A forms an angle of 45 ° with the y axis
  • the slow axis 50B forms an angle of ⁇ 45 ° with the y axis.
  • the polarization rotation elements 251 to 254 are cut out at a slight angle ⁇ with respect to the x-axis direction.
  • the polarization rotating elements 251 to 254 have a parallelogram shape having one side parallel to the y-axis and the other side having an angle ⁇ with the x-axis.
  • the fast axis 50A of the polarization rotation elements 251 to 254 forms an angle of 45 ° with one side and an angle of 45 ° - ⁇ with respect to the other side intersecting the one side when cut out from the polarization element substrate. .
  • the polarization rotation elements 251, 253 are arranged in the spacer step portions 225, 227 while maintaining the directions of the fast axis 50A and the slow axis 50B.
  • the polarization rotation elements 252 and 254 cut out from the polarization element substrate are arranged on the spacer step portions 226 and 228 with their front and back inverted with respect to the x axis or the y axis. Therefore, the fast axes 50A of the polarization rotators 252 and 254 make an angle of 90 ° with the fast axes 50A of the polarization rotators 251 and 253.
  • the polarization rotators 251, 253 function as polarization rotators that convert to left-handed circularly polarized light
  • the polarization rotators 252 and 254 function as right-handed circularly polarized lights.
  • the outer shapes of the spacer step portions 225 to 228 have parallelograms, which are similar shapes and are slightly larger than the outer shapes of the polarization rotation elements 251 to 254. Therefore, the polarization rotation elements 251 to 254 are arranged at the spacer step portions 225 to 228 corresponding to the respective shapes, that is, at predetermined positions.
  • Such a spacer 220 is provided in the assembly process of the laser light source device, etc., where the polarization rotators 251 and 253 for converting it to left-handed circularly polarized light and the polarization rotators 252 and 254 for right-handed circularly polarized light are arranged. Places are limited.
  • the laser light source device having such a configuration has the same effect as that of the above embodiment. Further, since the shapes of the polarization rotation elements 251 to 254 and the shapes of the spacer step portions 225 to 228 correspond to each other, the location where the polarization rotation elements are arranged is limited. As a result, in the assembly process of the laser light source device, the polarization rotation elements 251, 253 for converting the left-handed circularly polarized light and the polarization rotation elements 252, 254 for converting the right-handed circularly polarized light are mistaken at designated positions. It can be installed without the need for assembly workability.
  • the outer shapes of the polarization rotation elements 251 to 254 are determined according to the cross-sectional shapes (beam profiles) of the laser beams 71 to 74.
  • the outer shapes of the polarization rotation elements 251 to 254 have a parallelogram shape that is long in one direction.
  • Each polarization rotation element is arranged so that the length of the parallelogram matches the x-axis direction in which the divergence angle of each laser beam is large. That is, each polarization rotation element is selectively arranged according to the cross-sectional shape of each laser beam.
  • the number of polarization rotation elements that can be cut out from the polarization element substrate increases. As a result, cost reduction of the polarization rotation element and the laser light source device is realized.
  • the laser light source device further includes the spacer 20 provided above the plurality of semiconductor laser elements 101 to 104.
  • the spacer 20 includes a frame structure at a position where each of the plurality of laser beams passes.
  • Each of the plurality of polarization rotation elements 151 to 154 (or 251 to 254) is held in a frame structure.
  • the outer shape of each of the plurality of polarization rotation elements 151 to 154 (or 251 to 254) has a parallelogram shape.
  • the outer shape of the frame structure of the spacer 20 has a similar shape larger than the outer shape of each of the plurality of polarization rotation elements 151 to 154 (or 251 to 254).
  • the polarization rotation elements 151 and 153 (or 251 and 253) that convert to left-handed circularly polarized light and the polarization rotation elements 152 and 154 (or 252 and 254) that convert to right-handed circularly polarized light.
  • the placement direction or location is limited. As a result, the workability of assembling the laser light source device is improved.
  • the first polarization rotating element (polarization rotating elements 251, 253) or the second polarization rotating element (polarization rotating elements 252, 254) is each of a plurality of laser beams. Are selectively arranged according to the cross-sectional shape of.
  • the yield of the polarization rotation element that can be taken from the polarization element substrate is increased, and the cost reduction of the polarization rotation element and the laser light source device can be realized.
  • a laser light source device in which two semiconductor laser elements are arranged in the x-axis direction and two (2 ⁇ 2) semiconductor laser elements in the y-axis direction is shown as an example.
  • the laser light source device may include a plurality of semiconductor laser elements whose mounting numbers are increased in the x-axis direction and the y-axis direction. With such a configuration, a high-power laser light source device can be realized.
  • the array of semiconductor laser elements may be a two-dimensional array such as 2 ⁇ 4 or 4 ⁇ 4 or a one-dimensional array such as 1 ⁇ 4.
  • the laser light source device can further reduce the occurrence of interference and speckle.
  • the semiconductor laser elements 101 and 102 oscillate a red laser with a wavelength of 638 nm
  • the semiconductor laser elements 103 and 104 oscillate a red laser with a wavelength of 642 nm
  • the laser light source device is only required for the above polarization direction. Instead, it is possible to emit four types of laser light having different characteristics with respect to wavelength.
  • the present invention can appropriately modify or omit the embodiments within the scope of the invention.
  • 1 laser light source device 101-104 semiconductor laser device, 20 spacer, 25-28 spacer stepped portion, 30 base, 30A upper surface, 41-44 lens, 50A fast axis, 50B slow axis, 51-54 polarization rotation element, 151- 154 polarization rotator, 251-254 polarization rotator, 71-74 laser light, 81 linear polarization, 91-94 circular polarization.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)
  • Projection Apparatus (AREA)

Abstract

L'objectif de la présente invention est de fournir une source de lumière laser qui réduit l'apparition de franges d'interférence et de chatoiement, et réduit les augmentations de température dues aux oscillations laser. Le dispositif de source de lumière laser comprend: une base; une pluralité d'éléments laser à semi-conducteur qui émettent une pluralité de faisceaux laser ayant des directions de polarisation qui sont alignées dans une direction, chaque élément laser à semi-conducteur étant maintenu par la base; et un convertisseur de polarisation qui produit une perturbation de telle sorte que les directions de polarisation de la pluralité de faisceaux laser ne sont pas alignées dans une direction. Le convertisseur de polarisation comprend: des premiers rotateurs de polarisation qui sont agencés de façon sélective pour correspondre à des éléments laser à semi-conducteur qui émettent une partie de lumière laser, et convertissent la lumière polarisée de la partie de lumière laser en une lumière à polarisation circulaire ayant une rotation gauche; et des seconds rotateurs de polarisation qui sont agencés de façon sélective pour correspondre aux autres éléments laser à semi-conducteur qui émettent une autre partie de la lumière laser, et convertissent l'autre partie de la lumière laser en une lumière à polarisation circulaire ayant une rotation droite.
PCT/JP2018/038654 2018-10-17 2018-10-17 Dispositif de source de lumière laser WO2020079774A1 (fr)

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PCT/JP2018/038654 WO2020079774A1 (fr) 2018-10-17 2018-10-17 Dispositif de source de lumière laser
PCT/JP2019/039824 WO2020080220A1 (fr) 2018-10-17 2019-10-09 Dispositif de source de lumière laser
JP2020553114A JPWO2020080220A1 (ja) 2018-10-17 2019-10-09 レーザ光源装置

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JP2003037326A (ja) * 2001-05-17 2003-02-07 Nippon Electric Glass Co Ltd 半導体レーザー用キャップ
WO2012014798A1 (fr) * 2010-07-30 2012-02-02 ソニー株式会社 Unité source de lumière, dispositifs d'éclairage et d'affichage
JP2013069371A (ja) * 2011-09-22 2013-04-18 Sanyo Electric Co Ltd 半導体レーザー装置
US20150270682A1 (en) * 2014-03-24 2015-09-24 Osram Gmbh Light source arrangement
WO2015162767A1 (fr) * 2014-04-24 2015-10-29 Ｎｅｃディスプレイソリューションズ株式会社 Source de lumiere laser, projecteur equipe de source de lumiere laser, et procede de fabrication de source de lumiere laser
JP2016051902A (ja) * 2014-08-29 2016-04-11 日亜化学工業株式会社 半導体発光装置用の保持部材、光源装置及びその製造方法
WO2018100758A1 (fr) * 2016-11-30 2018-06-07 パナソニックＩｐマネジメント株式会社 Système optique et dispositif de source lumineuse

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JP2008060433A (ja) * 2006-09-01 2008-03-13 Rohm Co Ltd レーザアレイ
JP5751098B2 (ja) * 2010-09-08 2015-07-22 旭硝子株式会社 投射型表示装置
JP6019758B2 (ja) * 2012-05-30 2016-11-02 日亜化学工業株式会社 光源装置
JP6155579B2 (ja) * 2012-09-07 2017-07-05 カシオ計算機株式会社 発光素子組立体、投影装置及び発光素子組立体の製造方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003037326A (ja) * 2001-05-17 2003-02-07 Nippon Electric Glass Co Ltd 半導体レーザー用キャップ
WO2012014798A1 (fr) * 2010-07-30 2012-02-02 ソニー株式会社 Unité source de lumière, dispositifs d'éclairage et d'affichage
JP2013069371A (ja) * 2011-09-22 2013-04-18 Sanyo Electric Co Ltd 半導体レーザー装置
US20150270682A1 (en) * 2014-03-24 2015-09-24 Osram Gmbh Light source arrangement
WO2015162767A1 (fr) * 2014-04-24 2015-10-29 Ｎｅｃディスプレイソリューションズ株式会社 Source de lumiere laser, projecteur equipe de source de lumiere laser, et procede de fabrication de source de lumiere laser
JP2016051902A (ja) * 2014-08-29 2016-04-11 日亜化学工業株式会社 半導体発光装置用の保持部材、光源装置及びその製造方法
WO2018100758A1 (fr) * 2016-11-30 2018-06-07 パナソニックＩｐマネジメント株式会社 Système optique et dispositif de source lumineuse

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