JP2013145302A - Laser light source and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser light source and an image display device capable of designing an optical system in a compact size using an integrated collimate lens with a smaller cost.SOLUTION: The laser light source includes: a green laser light source 2 that outputs a green laser beam having a low NA (spread angle); an angle adjustment element 10 that adjusts the green laser beam to the NA (spread angle) identical to that of red and blue laser beams; and a shared collimator lens 11 that converts the color beams output from the green, red and blue laser light sources 2-4 into parallel beams. The angle adjustment element 10 is disposed at a position where the green beam does not interfere with the red and blue laser beams.

Description

  The present invention relates to a laser light source device and an image display device using a semiconductor laser, for example, a laser light source device used for a light source of an image display device.

  In recent years, a technique using a semiconductor laser as a light source of an image display device has attracted attention. This semiconductor laser has better color reproducibility, instantaneous lighting, longer life, and higher power consumption compared to mercury lamps that have been widely used in image display devices. It has various advantages such as being able to be made and being easy to downsize.

  In such an image display device, red, green, and blue laser beams that are the three primary colors of light are required. However, there is no semiconductor laser that directly outputs green laser light. For this reason, in a laser light source device used in an image display device, an excitation laser beam is output from a semiconductor laser, a solid-state laser element is excited by the excitation laser beam, and an infrared laser beam is output. A technique is known in which the wavelength of light is converted by a “wavelength conversion element” to output green laser light (see, for example, Patent Document 1).

  This green laser light source device is a semiconductor laser that outputs excitation laser light, a solid-state laser element that is excited by the excitation laser light and outputs basic laser light (infrared laser light), and converts the wavelength of the basic laser light. And a wavelength conversion element that outputs a half-wavelength laser beam (green laser beam), and a concave mirror that constitutes a resonator together with the solid-state laser element.

  The relay optical system also includes collimator lenses that convert the laser beams of the respective colors emitted from the laser light source devices into parallel beams, and first and first guides that direct the laser beams of the respective colors that have passed through the collimator lenses in a required direction. 2 dichroic mirrors, a diffusion plate for diffusing the laser light guided by the dichroic mirror, and a field lens for converting the laser light that has passed through the diffusion plate into a convergent laser.

JP 2008-16833 A

  In such a conventional laser light source device, since the collimating lens is provided for each laser light source, the provision of each collimating lens causes an increase in cost.

  An object of the present invention is to provide a laser light source device and an image display device that can reduce the cost by reducing the optical layout, making the collimating lens one.

  The laser light source device of the present invention includes a green, red, and blue laser light source device that outputs green, red, and blue laser light, an angle adjustment element that adjusts the green laser light to a spread angle equivalent to that of the red and blue laser light, A common collimator lens that converts the laser beams of the respective colors emitted from the green, red, and blue laser light source devices into parallel beams, and the angle adjusting element is configured such that the green laser beam does not interfere with the red and blue laser beams. Take the configuration, arranged in position.

  The image display device of the present invention employs a configuration including the laser light source device.

  According to the present invention, a single collimating lens can be obtained with a compact optical layout, and the cost can be reduced.

1 is a schematic diagram of an image display device including a laser light source device according to Embodiment 1 of the present invention. The schematic diagram which shows the condition of the laser beam in the laser light source apparatus which concerns on the said Embodiment 1. The figure explaining the light source arrangement | positioning of the laser light source apparatus which concerns on the said Embodiment 1. FIG. The figure explaining the inclination arrangement | positioning of the laser light source apparatus which concerns on the said Embodiment 1. FIG. The figure explaining the light source arrangement | positioning of the laser light source apparatus which concerns on Embodiment 2 of this invention. The perspective view which shows the example which incorporated this image display apparatus provided with the laser light source device which concerns on Embodiment 3 of this invention in the notebook type information processing apparatus.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram of an image display device including a laser light source device according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the image display apparatus 1 projects and displays a required image on a screen. The image display device 1 includes a green laser light source device 2 that outputs green laser light, a red laser light source device 3 that outputs red laser light, a blue laser light source device 4 that outputs blue laser light, and a video signal. The liquid crystal reflective spatial light modulator 5 that modulates the laser light from each of the laser light source devices 2 to 4 and the laser light from each of the laser light source devices 2 to 4 are reflected and applied to the spatial light modulator 5. A polarization beam splitter 6 that transmits the modulated laser light emitted from the spatial light modulator 5, a relay optical system 7 that guides the laser light emitted from each of the laser light source devices 2 to 4 to the polarization beam splitter 6, and a polarization beam splitter And a projection optical system 8 that projects the modulated laser light transmitted through 6 onto the screen S.

  The relay optical system 7 adjusts the angle of adjusting the green laser light emitted from the green laser light source device 2 with a small low NA (spreading angle) and the green laser light to the same NA (spreading angle) as the red and blue laser light. The element 10, the common collimator lens 11 that converts the laser beams of the respective colors emitted from the green, red, and blue laser light source devices 2 to 4 into parallel beams, and the laser beams of the respective colors that have passed through the common collimator lens 11 in the required directions. The first, second, and third dichroic mirrors 12, 13, and 14, the diffusion plate 15 that diffuses the laser light guided by the dichroic mirrors 12, 13, and 14, and the laser light that has passed through the diffusion plate 15 And a field lens 16 for converting into a converging laser.

  The angle adjusting element 10 adjusts the green laser light to an NA (a spread angle, also referred to as a radiation angle) equivalent to that of the red and blue laser lights. The red and blue laser beams have an NA of about 60 °, whereas the green laser beam has only an NA of 2 to 3 °. The NA of the green laser beam is adjusted to be the same as the NA of the red and blue laser beams. There is a need to. Therefore, the angle adjusting element 10 is specifically a diffusing element that increases the NA of the green laser light to a predetermined NA. The angle adjusting element 10 may be anything as long as it has a function of increasing the NA (expansion angle) of the green laser light. For example, the angle adjusting element 10 includes a concave lens having a refraction function and a diffusion plate having a function such as diffraction. In the following drawings, a concave lens is taken as an example for convenience of explanation.

  With respect to the optical axis of the green laser light from the green laser light source device 2, the optical axis of the blue laser light and the optical axis of the red laser light face each other and are arranged at a desired angle. Further, the three dichroic mirrors 12, 13, and 14 are arranged so as to be inclined at a desired angle with respect to the optical axes of the red, green, and blue laser beams, and the blue laser beam, the red laser beam, and the green laser beam. Light is guided to the same optical path by the three dichroic mirrors 12, 13, and 14.

  The dichroic mirrors 12, 13, and 14 have films formed on their surfaces for transmitting and reflecting laser light having a predetermined wavelength. The dichroic mirror 12 reflects red laser light. The dichroic mirror 13 transmits red laser light and reflects green laser light. The dichroic mirror 14 transmits red laser light and green laser light and reflects blue laser light.

  Each of these optical members is supported by the casing 21. The casing 21 functions as a radiator that dissipates heat generated by the laser light source devices 2 to 4 and is formed of a material having high thermal conductivity such as aluminum or copper.

  The green laser light source device 2 is attached to an attachment portion 22 formed in the housing 21 in a state of protruding toward the side.

  The red laser light source device 3 and the blue laser light source device 4 are configured by a so-called CAN package, and the optical axis is positioned on the central axis of the can-shaped exterior portion with the laser chip that outputs the laser light supported by the stem. Are arranged to be.

  The green laser light source device 2 includes a semiconductor laser 31 that outputs excitation laser light, a FAC (Fast-Axis Collimator) lens 32 that is a condensing lens that condenses the excitation laser light output from the semiconductor laser 31, and a rod. A lens 33, a solid-state laser element 34 that outputs a basic laser beam (infrared laser beam) when excited by an excitation laser beam, and outputs a half-wavelength laser beam (green laser beam) by converting the wavelength of the basic laser beam Wavelength converting element (optical element) 35, a concave mirror 36 constituting a resonator together with the solid-state laser element 34, a glass cover 37 for preventing leakage of excitation laser light and fundamental wavelength laser light, and a base supporting each part The base 38 and the cover body 39 which covers each part are provided.

  FIG. 2 is a schematic diagram showing a state of laser light in the green laser light source device 2.

  As shown in FIG. 2, the laser chip 41 of the semiconductor laser 31 outputs excitation laser light having a wavelength of 808 nm. The FAC lens 32 reduces the spread of the first axis of the laser light (the direction orthogonal to the optical axis direction and along the drawing sheet). The rod lens 33 reduces the spread of the slow axis of laser light (in the direction orthogonal to the drawing sheet).

The solid-state laser element 34 is a so-called solid-state laser crystal, and is excited by excitation laser light having a wavelength of 808 nm that has passed through the rod lens 33 to output a fundamental wavelength laser light (infrared laser light) having a wavelength of 1064 nm. The solid-state laser element 34, Y (yttrium) is obtained by doping Nd (neodymium) to VO ₄ Inorganic optically active substances consisting of (vanadate) (crystal), and more specifically, the YVO ₄ as the base material Doping was performed by substituting Nd ⁺³ which is an element that fluoresces Y.

  On the side of the solid-state laser element 34 facing the rod lens 33, a film having a function of preventing reflection of excitation laser light with a wavelength of 808 nm and high reflection with respect to fundamental wavelength laser light with a wavelength of 1064 nm and half-wavelength laser light with a wavelength of 532 nm. 42 is formed. On the side of the solid-state laser element 34 facing the wavelength conversion element 35, a film 43 having an antireflection function for a fundamental wavelength laser beam having a wavelength of 1064 nm and a half wavelength laser beam having a wavelength of 532 nm is formed.

  The wavelength conversion element 35 is a so-called SHG (Second Harmonics Generation) element, which converts the wavelength of a fundamental wavelength laser beam (infrared laser beam) having a wavelength of 1064 nm output from the solid-state laser element 34 to a half-wavelength laser having a wavelength of 532 nm. Light (green laser light) is generated.

  On the side of the wavelength conversion element 35 facing the solid-state laser element 34, a film 44 having functions of preventing reflection with respect to the fundamental wavelength laser beam with a wavelength of 1064 nm and highly reflecting with respect to the half wavelength laser beam with a wavelength of 532 nm is formed. On the side of the wavelength conversion element 35 facing the output mirror 36, a film 45 having an antireflection function for the fundamental wavelength laser beam having a wavelength of 1064 nm and the half wavelength laser beam having a wavelength of 532 nm is formed.

  The output mirror 36 has a concave surface on the side facing the wavelength conversion element 35, and the concave surface has a function of high reflection with respect to a fundamental wavelength laser beam with a wavelength of 1064 nm and antireflection with respect to a half wavelength laser beam with a wavelength of 532 nm. A film 46 is formed. As a result, the fundamental wavelength laser beam having a wavelength of 1064 nm resonates and is amplified between the film 42 of the solid-state laser element 34 and the film 46 of the output mirror 36.

  In the wavelength conversion element 35, a part of the fundamental wavelength laser light having a wavelength of 1064 nm incident from the solid-state laser element 34 is converted into a half-wavelength laser light having a wavelength of 532 nm, and the fundamental wavelength of 1064 nm that has passed through the wavelength conversion element 35 without being converted is converted. The wavelength laser beam is reflected by the output mirror 36, is incident again on the wavelength conversion element 35, and is converted into a half-wavelength laser beam having a wavelength of 532 nm. The half-wavelength laser light having a wavelength of 532 nm is reflected by the film 44 of the wavelength conversion element 35 and is emitted from the wavelength conversion element 35.

  Here, the laser beam B1 incident on the wavelength conversion element 35 from the solid-state laser element 34, converted in wavelength by the wavelength conversion element 35, and emitted from the wavelength conversion element 35, and once reflected by the output mirror 36 and converted in wavelength. In a state where the laser beam B2 incident on the element 35, reflected by the film 44 and emitted from the wavelength conversion element 35 overlaps with each other, the half-wavelength laser light having a wavelength of 532 nm and the fundamental wavelength laser light having a wavelength of 1064 nm interfere with each other. Cause output to drop.

  Therefore, in this case, the wavelength conversion element 35 is inclined with respect to the optical axis direction so that the laser beams B1 and B2 do not overlap each other due to the refracting action on the entrance surface and the exit surface. Interference between the wavelength laser beam and the fundamental wavelength laser beam having a wavelength of 1064 nm is prevented, so that a decrease in output can be avoided.

  The glass cover 37 shown in FIG. 1 is formed with a film that does not transmit these laser beams in order to prevent the excitation laser beam having a wavelength of 808 nm and the fundamental wavelength laser beam having a wavelength of 1064 nm from leaking to the outside. ing.

  Hereinafter, the light source arrangement of the laser light source device configured as described above will be described.

  FIG. 3 is a diagram illustrating the light source arrangement of the green, red, and blue laser light source devices 2 to 4.

  The relay optical system 7 of the laser light source device of the present embodiment includes a green laser light emitted from the green laser light source device 2 with a small low NA (expansion angle), a green laser light that is equivalent to red and blue laser light. An angle adjusting element 10 that adjusts to (a divergence angle) and a common collimator lens 11 that converts the laser beams of the respective colors emitted from the green, red, and blue laser light source devices 2 to 4 into parallel beams.

(1) Arrangement of green, red, and blue laser light source devices 2 to 4 by using one common collimator lens 11 The laser light of each color emitted from the green, red, and blue laser light source devices 2 to 4 is one common collimator lens. 11 is shared. In the present embodiment, the red laser light source device 3 and the blue laser light source device 4 are disposed so as to be inclined toward the center of the common collimator lens 11. Thereby, as will be described later, the outer diameter of the common collimator lens 11 can be reduced.

From the above, as shown in FIG. 3 a, the light emitting surface of the red laser light source device 3 or the blue laser light source device 4 is disposed at the respective focal lengths f _R and f _B of the common collimator lens 11. For example, when the NA of red and blue laser light is about 60 °, f _R = 10.42 (mm) and f _B = 10.16 (mm). The focal lengths f _R and f _B are determined in consideration of the lens diameter, the lens material, the curvature, the lens thickness of the common collimator lens 11, and the required beam width of the parallel beam.

  As shown in FIG. 3b, the angle α formed by the optical axis of the laser light of the green laser light source device 2 and the optical axis of the laser light of the red laser light source device 3 or the blue laser light source device 4 is the lens diameter and will be described later. It is determined in consideration of optical coherence to

(2) Arrangement of Green, Red, and Blue Laser Light Sources 2 to 4 As shown in FIG. 3, the green laser light source device 2 is located on the projection side (that is, the light emitting surface of the red laser light source device 3 and the blue laser light source device 4). It is arranged in the opposite direction to the common collimator lens 11 side). Green laser light having a small emission angle is incident on the angle adjusting element 10 from the green laser light source device 2 through the red laser light source device 3 and the blue laser light source device 4. Since the green laser light from the green laser light source device 2 has a small radiation angle, the red laser light source device 3 and the blue laser light source device 4 in the shape of a semiconductor laser (for example, a 5.6φ CAN package product) are spaced at a slight distance. Can be made incident on the angle adjusting element 10 without interfering with the red laser light source device 3 and the blue laser light source device 4. The green, red, and blue laser light source devices 2 to 4 are arranged on the same plane. As a result, the thickness in the thickness direction of the green, red, and blue laser light source devices 2 to 4 is reduced, and the entire device (here, the image display device 1) is reduced in size and thickness.

  The green, red, and blue laser light source devices 2 to 4 are preferably arranged on the same plane, but the green, red, and blue laser light source devices 2 to 4 may be used when there is no limit in the thickness direction of the laser light source device. May not be arranged on the same plane.

(3) Arrangement of Angle Adjusting Element 10 that is a Diffusing Element that Expands the NA of Green Laser Light As shown in FIG. 3c, the angle adjusting element 10 projects more than the light emitting surfaces of the red laser light source device 3 and the blue laser light source device 4. It is arranged on the side (that is, the common collimator lens 11 side) and at a position where it does not come into contact with the laser light of the red laser light source device 3 and the blue laser light source device 4 (does not interfere with the laser light). More specifically, as shown in FIG. 3c, the blue laser beam or the red laser beam is a light beam having a spread, and is disposed at a position where the light beam does not interfere with the angle adjusting element 10. In FIG. 3, the angle adjusting element 10 is arranged at a position where the corner portion of the angle adjusting element 10 does not interfere with the laser light of the red laser light source device 3 or the blue laser light source device 4.

  By the way, the position where the angle adjusting element 10 does not interfere with the blue laser light and the red laser light, or the position where the blue laser light source device 4 and the red laser light source device 3 do not interfere with the green laser light is on the optical axis of the green laser light. In FIG. 2, there are two locations, the projection side with respect to the light emitting surfaces of the red laser light source device 3 and the blue laser light source device 4, and the rear side with respect to the light emitting surface (the opposite side to the projection side). An example of the latter arrangement will be described later with reference to the second embodiment.

  FIG. 4 is a diagram for explaining an inclined arrangement of the red laser light source device 3 and the blue laser light source device 4. FIG. 4A shows a case where the laser is inclined and FIG. 4B shows a case where the laser is not inclined.

  As shown in FIG. 4A, the red laser light source device 3 and the blue laser light source device 4 are disposed so as to be inclined toward the center of the common collimator lens 11. Compared to the case where the laser shown in FIG. 4B is not inclined, the outer diameter of the common collimator lens 11A can be significantly reduced. As a result, the size of the common collimator lens 11 is reduced, and the entire apparatus (here, the image display apparatus 1) is reduced in size and thickness.

  The red laser light source device 3 and the blue laser light source device 4 have no problem as functions even when the desired angle is not inclined. However, since the common collimator lens 11 becomes large and the size, thickness, and weight of the entire apparatus increase, it is preferable to tilt the desired angle.

  As described above in detail, the laser light source device according to the present embodiment is a green laser beam having a small low NA (expansion angle) emitted from the green laser light source device 2, and the green laser beam is red and blue laser beam. An angle adjustment element 10 for adjusting to an equivalent NA (divergence angle), and a common collimator lens 11 that converts the laser beams of the respective colors emitted from the green, red, and blue laser light source devices 2 to 4 into parallel beams, The adjustment element 10 is disposed at a position where the green laser beam does not interfere with the red and blue laser beams. In the present embodiment, the angle adjusting element 10 is on the projection side of the red laser light source device 3 and the blue laser light source device 4 on the optical axis of the green laser light and interferes with the red and blue laser light. It is placed in a position that does not.

  With this configuration, a single collimating lens can be obtained with a compact optical layout, and costs can be reduced.

  In the present embodiment, the red laser light source device 3 and the blue laser light source device 4 are arranged so that the optical axis is inclined toward the center of the common collimator lens 11, so that the outer diameter of the common collimator lens 11 is increased. The overall device can be made smaller, thinner and lighter.

  In the present embodiment, the green, red, and blue laser light source devices 2 to 4 are arranged on the same plane, so that the thickness can be reduced and the entire device can be reduced in size and thickness. Can do.

(Embodiment 2)
FIG. 5 is a diagram for explaining the light source arrangement of the laser light source apparatus according to Embodiment 2 of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals, and description of overlapping portions is omitted.

  As shown in FIGS. 1 and 5, the angle adjusting element 10 is disposed behind the light emitting surfaces of the red laser light source device 3 and the blue laser light source device 4.

(1) Arrangement of green, red and blue laser light source devices 2 to 4 by using one common collimator lens 11 As in the first embodiment, lasers of respective colors emitted from the green, red and blue laser light source devices 2 to 4 The light is shared by one common collimator lens 11. In the present embodiment, the red laser light source device 3 and the blue laser light source device 4 are arranged so as to be inclined toward the center of the common collimator lens 11, thereby reducing the outer diameter of the common collimator lens 11. it can.

(2) Arrangement of Green, Red, and Blue Laser Light Source Devices 2 to 4 As shown in FIG. 5, the green laser light source device 2 is arranged behind the red laser light source device 3 and the blue laser light source device 4. Green laser light having a small emission angle from the green laser light source device 2 is incident on the angle adjusting element 10. The incident green laser light is spread to an NA equivalent to that of the red and blue laser light by the angle adjusting element 10 and is incident on the common collimator lens 11 between the red laser light source device 3 and the blue laser light source device 4.

  Further, the green, red, and blue laser light source devices 2 to 4 are arranged on the same plane, thereby reducing the thickness in the thickness direction of the green, red, and blue laser light source devices 2 to 4 and reducing the overall size of the device. Thinning can be achieved.

(3) Arrangement of Angle Adjusting Element 10 that is a Diffusing Element that Expands the NA of Green Laser Light As shown in FIG. 5, the angle adjusting element 10 is behind the light emitting surfaces of the red laser light source device 3 and the blue laser light source device 4. Place at the position. Further, as shown in FIG. 5a, the red laser light source device 3 and the blue laser light source device 4 have the shape of a semiconductor laser (for example, a 5.6φ CAN package product), and the green laser emitted from the angle adjusting element 10 Since the light is a light beam having a spread, it is arranged at a position where this light beam does not interfere with the red laser light source device 3 and the blue laser light source device 4. In FIG. 5, the angle adjusting element 10 is arranged at a position where the emitted light from the angle adjusting element 10 does not interfere with the laser light of the red laser light source device 3 or the blue laser light source device 4.

  As described above, according to the present embodiment, the angle adjusting element 10 is on the rear side of the light emitting surfaces of the red laser light source device 3 and the blue laser light source device 4 on the optical axis of the green laser light, Are disposed at positions that do not interfere with the blue laser light.

  With this configuration, as in the first embodiment, a single collimating lens can be provided with a compact optical layout, and costs can be reduced.

(Embodiment 3)
FIG. 6 is a perspective view showing an example in which the present image display device including the laser light source device according to Embodiment 3 of the present invention is built in a notebook information processing device.

  As shown in FIG. 6, the housing 152 of the information processing apparatus 151 is provided with a housing space in which the image display apparatus 1 is stored so as to be able to appear and retract, on the back side of the keyboard. The image display device 1 is accommodated in the housing 152 when not in use, and is pulled out of the housing 152 when in use. When in use, the image display apparatus 1 projects the laser light from the image display apparatus 1 onto the screen by rotating the image display apparatus 1 at a required angle with respect to a base portion 153 that rotatably supports the image display apparatus 1. Can do.

  The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this.

  In the above embodiments, the names of the laser light source device and the image display device are used. However, this is for convenience of explanation, and may be a laser light output device, an image projection device, or the like. The angle adjusting element may be called a concave lens, a diffusing lens, a diffusing plate, or the like.

  Further, although an example in which the present image display device is applied to a notebook information processing device has been described, the present invention may be applied to any electronic device provided that the present laser light source device is provided.

  INDUSTRIAL APPLICABILITY The laser light source device and the image display device according to the present invention have the effect of reducing the cost by using a single collimating lens with a compact optical layout, and are used for the light source of the image display device. It is useful as such.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Green laser light source apparatus 3 Red laser light source apparatus 4 Blue laser light source apparatus 5 Spatial light modulator 6 Polarization beam splitter 7 Relay optical system 10 Angle adjustment element 11 Common collimator lens 12, 13, 14 Dichroic mirror 15 Diffusion plate 16 Field lens

Claims (7)

Green, red, and blue laser light source devices that output green, red, and blue laser light; and
An angle adjusting element that adjusts the green laser beam to the same spread angle as the red and blue laser beams;
A common collimator lens that converts laser light of each color emitted from the green, red, and blue laser light source devices into a parallel beam;
The said angle adjustment element is a laser light source device arrange | positioned in the position where a green laser beam does not interfere with a red and blue laser beam.   The angle adjusting element is disposed on the projection side of the light emission surfaces of the red laser light source device and the blue laser light source device on the optical axis of the green laser light, and at a position that does not interfere with the red and blue laser light. The laser light source device according to claim 1.   The angle adjusting element is disposed on the optical axis of the green laser light and behind the light emitting surfaces of the red laser light source device and the blue laser light source device, and at a position that does not interfere with the red and blue laser light. The laser light source device according to claim 1.   2. The laser light source device according to claim 1, wherein at least one of the green, red, and blue laser light source devices is disposed so that an optical axis is directed toward a center of the common collimator lens.   The laser light source device according to claim 1, wherein the green laser light source device is disposed between the red laser light source device and the blue laser light source device.   The laser light source device according to claim 1, wherein the green, red, and blue laser light source devices are arranged on the same plane. An image display apparatus provided with the laser light source apparatus as described in any one of Claims 1 thru | or 6.

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