JP6383166B2 - Light irradiation apparatus and drawing apparatus - Google Patents

Description

  The present invention relates to a light irradiation apparatus and a drawing apparatus.

  Conventionally, a technique for uniformly irradiating a predetermined surface with laser light emitted from a light source such as a semiconductor laser has been proposed. For example, in a light irradiation device in which laser light incident from a light source unit is divided by a plurality of lenses in a cylindrical lens array, and an irradiation area of light from the plurality of lenses is overlapped on an irradiation surface by another lens, the light source unit An optical path length difference generation unit is provided between the cylindrical lens array and the cylindrical lens array. The optical path length difference generating unit is provided with a plurality of light transmitting parts that mutually cause an optical path length difference longer than the coherence length (coherence distance) of the laser light, and the light that has passed through the plurality of light transmitting parts is a plurality of light transmitting parts. Each enters the lens. Thereby, generation | occurrence | production of an interference fringe is prevented and uniform intensity distribution of the light irradiated on an irradiation surface is achieved (for example, refer patent documents 1 thru | or 3 as such an apparatus).

JP-A 61-169815 JP 2004-12757 A JP 2006-49656 A

  By the way, in a drawing apparatus in which a spatial light modulator is arranged on the irradiation surface in the light irradiation apparatus and the pattern is drawn by irradiating the object with the spatially modulated light, the pattern intensity is uniformed in order to speed up the pattern drawing. There is a need for a light irradiation apparatus that can irradiate an irradiation surface with high-intensity light having a distribution.

  This invention is made | formed in view of the said subject, and it aims at providing the light irradiation apparatus which can irradiate an irradiation surface with the high intensity | strength light which has uniform intensity distribution.

The invention according to claim 1 is a light irradiation device, comprising a plurality of light source units arranged on one surface, wherein the plurality of light source units are directed from different directions along the surface to a predetermined position. A light source unit that emits laser light, and an irradiation optical system that is disposed at the predetermined position and guides the laser light from the light source unit to an irradiation surface along an optical axis, and the irradiation optical system includes the light A plurality of lenses arranged in an arrangement direction perpendicular to the axis and along the surface, and divided lens parts for dividing light incident from the plurality of light source parts by the plurality of lenses, and arranged in the arrangement direction; And a plurality of light transmitting portions having different optical path lengths, wherein a plurality of light beams that have passed through the plurality of lenses are incident on the plurality of light transmitting portions, respectively, and a path of the laser light Before the optical path length difference generator A condensing lens unit that is disposed on the irradiation surface side and overlaps the irradiation regions of the plurality of light fluxes from the plurality of light transmitting units on the irradiation surface, and the split lens unit and the optical path length difference generation unit, Are arranged close to each other, and images of a plurality of light sources included in the plurality of light source units are formed in the vicinity of an exit surface of each of the plurality of lenses, and the plurality of light beams from the plurality of lenses are The width of the light flux that is incident on the plurality of light transmitting parts while diverges in the arrangement direction and is emitted from the respective emission surfaces of the plurality of light transmission parts with respect to the arrangement direction is the pitch of the plurality of light transmission parts. rather smaller than, the plurality of light transmitting portions, the array direction of the width of the light beam on the exit surface of the largest light transmitting portion is the length in the direction of the optical axis w _s, the plurality of light transmission The effective area on the exit surface of each of the parts The width in the arrangement direction is p ′, the width in the arrangement direction of the light flux on the emission surface of each of the plurality of lenses is w _h , and the focal length of each of the two lens surfaces of the plurality of lenses is f _h , The incident angle of light incident on each of the plurality of lenses from the light source unit having the maximum incident angle of the laser beam to the divided lens unit among the plurality of light source units is θ _i , and the emission of each of the plurality of lenses. The width of the gap between the surface and the incident surface of each of the plurality of light transmitting portions is d _s , and the length of the light transmitting portion having the largest length in the direction of the optical axis among the plurality of light transmitting portions is set. t _s , the half angle of the divergence of the light passing through the condensing point on the exit surface of each of the plurality of lenses is θ _d , and the half angle of the divergence of the light inside the optical path length difference generation unit is θ ′ _d , The pitch of the plurality of light transmitting parts is p, and each of the plurality of light transmitting parts is On the exit surface , w _s ≦ p ′ (where w _h = 2f _h · tan θ _i , w _s = w) , where the width in the arrangement direction of the ineffective regions existing at the edges and in the vicinity thereof is p _{o. h} +2 (d _s · tan θ _d + t _s · tan θ ′ _d ) and p ′ = p−2 p _o ) is satisfied .

The invention according to claim 2 is a light irradiation device, comprising a plurality of light source units arranged on one surface, wherein the plurality of light source units are directed from different directions along the surface to a predetermined position. A light source unit that emits laser light, and an irradiation optical system that is disposed at the predetermined position and guides the laser light from the light source unit to an irradiation surface along an optical axis, and the irradiation optical system includes the light A plurality of lenses arranged in a direction perpendicular to the axis and along the surface, a split lens unit that divides light incident from the plurality of light source units by the plurality of lenses, and a direction perpendicular to the optical axis And a plurality of light transmitting portions that have different optical path lengths, and light that has passed through the plurality of lenses is incident on the light transmitting portions, respectively, and the divided lens portion And the optical path length difference generator Moni, an intermediate scaling unit constituting the enlargement optical system, from the than the optical path length difference generator in a path of the laser beam is arranged on the radiation surface side, the plurality of light transmitting portions in on the irradiation surface obtain the Bei a condensing lens unit superposing light irradiation region.

  A third aspect of the present invention is the light irradiation apparatus according to the second aspect, wherein the intermediate zooming unit forms a double-sided telecentric optical system.

  Invention of Claim 4 is the light irradiation apparatus of Claim 3, Comprising: The said intermediate | middle zooming part image | photographs the image of the output surface of these lenses in or in the vicinity of these light transmissive parts. Form.

The invention according to claim 5 is a light irradiation device, comprising a plurality of light source units arranged on one surface, wherein the plurality of light source units are directed from different directions along the surface to a predetermined position. A light source unit that emits laser light, and an irradiation optical system that is disposed at the predetermined position and guides the laser light from the light source unit to an irradiation surface along an optical axis, and the irradiation optical system includes the light A plurality of lenses arranged in a direction perpendicular to the axis and along the surface, a split lens unit that divides light incident from the plurality of light source units by the plurality of lenses, and a direction perpendicular to the optical axis And a plurality of light transmitting portions having different light path lengths, and light passing through the plurality of lenses is incident on the light transmitting portions, respectively, and the light path length difference. A plurality of emission of the plurality of light transmitting parts through the generation unit Folding the light emitted from the reflecting portion to be incident to the plurality of the exit surface, disposed on the irradiation surface side of the optical path length difference generator in a path of said laser beam, said at on the irradiation surface obtain Bei a condensing lens unit superposing irradiation region of the light from a plurality of light-transmitting portions.

  Invention of Claim 6 is the light irradiation apparatus of Claim 5, Comprising: The said reflection part is the said several in parallel with the emission direction of the said light in the said light emission direction. Each is incident on the exit surface.

Invention of Claim 7 is drawing apparatus, Comprising: The light irradiation apparatus in any one of Claim 1 thru | or 6 , The spatial light modulator arrange | positioned at the said irradiation surface in the said light irradiation apparatus, The said, A projection optical system for guiding light spatially modulated by a spatial light modulator onto an object, a movement mechanism for moving an irradiation position of the spatially modulated light on the object, and an irradiation position of the irradiation mechanism by the movement mechanism A control unit that controls the spatial light modulator in synchronization with the movement.

  According to the present invention, it is possible to irradiate the irradiation surface with high-intensity light having a uniform intensity distribution.

It is a figure which shows the structure of the drawing apparatus which concerns on 1st Embodiment. It is a figure which shows the structure of a light irradiation apparatus. It is a figure which shows the structure of a light irradiation apparatus. It is a figure which shows a part of division lens part and an optical path length difference production | generation part. It is a figure which shows intensity distribution of the light on an irradiation surface. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows intensity distribution of the light on an irradiation surface. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the structure of the light irradiation apparatus which concerns on 2nd Embodiment. It is a figure which shows the structure of the light irradiation apparatus which concerns on 2nd Embodiment. It is a figure which shows the vicinity of a division | segmentation lens part. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of an optical path length difference production | generation part. It is a figure which shows the other example of a light irradiation apparatus. It is a figure which shows the other example of a light irradiation apparatus.

  FIG. 1 is a diagram showing a configuration of a drawing apparatus 1 according to the first embodiment of the present invention. The drawing apparatus 1 is a direct drawing apparatus that draws a pattern by irradiating the surface of a substrate 9 such as a semiconductor substrate or a glass substrate, to which a photosensitive material is applied, with a light beam. The drawing apparatus 1 includes a stage 21, a moving mechanism 22, a light irradiation device 31, a spatial light modulator 32, a projection optical system 33, and a control unit 11. The stage 21 holds the substrate 9, and the moving mechanism 22 moves the stage 21 along the main surface of the substrate 9. The moving mechanism 22 may rotate the substrate 9 about an axis perpendicular to the main surface.

  The light irradiation device 31 irradiates the spatial light modulator 32 with line-shaped light via the mirror 39. Details of the light irradiation device 31 will be described later. The spatial light modulator 32 is, for example, a diffraction grating type and a reflection type, and is a diffraction grating capable of changing the depth of the grating. The spatial light modulator 32 is manufactured using a semiconductor device manufacturing technique. The diffraction grating type optical modulator used in the present embodiment is, for example, GLV (Grating Light Valve) (registered trademark of Silicon Light Machines (Sunnyvale, Calif.)). The spatial light modulator 32 has a plurality of grating elements arranged in a line, and each grating element is between a state where the first-order diffracted light is emitted and a state where zero-order diffracted light (0th-order light) is emitted. Transition. In this way, the spatially modulated light is emitted from the spatial light modulator 32.

  The projection optical system 33 includes a light shielding plate 331, a lens 332, a lens 333, a diaphragm plate 334, and a focusing lens 335. The light shielding plate 331 shields part of the ghost light and the high-order diffracted light and allows the light from the spatial light modulator 32 to pass through. The lenses 332 and 333 constitute a zoom unit. The diaphragm plate 334 shields the (± 1) order diffracted light (and higher order diffracted light) and allows the 0th order diffracted light to pass through. The light that has passed through the diaphragm plate 334 is guided onto the main surface of the substrate 9 by the focusing lens 335. In this way, the light spatially modulated by the spatial light modulator 32 is guided onto the substrate 9 by the projection optical system 33.

  The control unit 11 is connected to the light irradiation device 31, the spatial light modulator 32, and the moving mechanism 22, and controls these configurations. In the drawing apparatus 1, when the moving mechanism 22 moves the stage 21, the irradiation position on the substrate 9 of the light from the spatial light modulator 32 moves. Further, the control unit 11 controls the spatial light modulator 32 in synchronization with the movement of the irradiation position by the moving mechanism 22. Thereby, a desired pattern is drawn on the photosensitive material on the substrate 9.

  2 and 3 are diagrams showing the configuration of the light irradiation device 31. FIG. 2 and 3, the direction parallel to the optical axis J1 of the irradiation optical system 5 to be described later is shown as the Z direction, and the directions perpendicular to the Z direction and orthogonal to each other are shown as the X direction and the Y direction (hereinafter referred to as the “Z direction”) The same). FIG. 2 shows the configuration of the light irradiation device 31 viewed along the Y direction, and FIG. 3 shows the configuration of the light irradiation device 31 viewed along the X direction.

  The light irradiation device 31 shown in FIGS. 2 and 3 includes a light source unit 40 and an irradiation optical system 5. The light source unit 40 includes a plurality of light source units 4, and each light source unit 4 includes one light source 41 and one collimator lens 42. The light sources 41 of the plurality of light source units 4 are arranged approximately in the X direction on a plane parallel to the ZX plane (hereinafter referred to as “light source arrangement plane”). Laser light emitted from each light source 41 is collimated by the collimator lens 42 and enters the irradiation optical system 5. The light source unit 40 is provided with a mechanism (not shown) that adjusts the emission direction of the laser light emitted from the light source unit 4. By adjusting the mechanism, it is possible to match the positions of the split lens unit 62 on the irradiation optical system 5 irradiated with the laser light from the plurality of light source units 4 in the X direction and the irradiation surface 320 in the Y direction. Become. As described above, in the light source unit 40, the plurality of light source units 4 arranged on the light source array surface are moved from the different directions along the light source array surface to the same position (divided lens unit 62 described later) on the irradiation optical system 5. A laser beam is emitted. In the light source unit 40, since the plurality of light source sections 4 are attached to a support member (not shown), the plurality of light sources 41 can be efficiently cooled.

  The irradiation optical system 5 is arranged at the irradiation position of the laser light from the plurality of light source units 4. The irradiation optical system 5 is a surface of the spatial light modulator 32 that is an irradiation surface (indicated by a broken line denoted by reference numeral 320 in FIGS. 2 and 3) along the optical axis J1 of the laser light, that is, a plurality of light beams. To the surface of the lattice element. As described above, since the light from the light irradiation device 31 is irradiated to the spatial light modulator 32 via the mirror 39, the light irradiation device 31 actually includes the mirror 39 as a constituent element. In FIG. 2 and FIG. 3, the mirror 39 is omitted for convenience of illustration (the same applies hereinafter).

  The irradiation optical system 5 includes an optical path length difference generation unit 61, a split lens unit 62, and a condenser lens unit 63. In the irradiation optical system 5, these components are arranged along the optical axis J <b> 1 in this order from the light source unit 40 toward the irradiation surface 320 in the order of the split lens unit 62, the optical path length difference generation unit 61, and the condenser lens unit 63. . The collimated laser beams from the plurality of light source units 4 enter the split lens unit 62.

  FIG. 4 is an enlarged view showing a part of the split lens unit 62 and the optical path length difference generation unit 61. The split lens unit 62 includes a plurality of lenses 620 (hereinafter, referred to as “lens”) arranged closely at a constant pitch in a direction (here, the X direction) perpendicular to the optical axis J1 of the irradiation optical system 5 and along the light source array plane. "Element lens 620"). Each element lens 620 has a long block shape in the Y direction, and includes a first lens surface 621 which is a side surface located on the (−Z) side (light source unit 40 side), and a (+ Z) side (optical path length difference generation unit 61). 2nd lens surface 622 which is a side surface located in the side. When viewed along the Y direction, the first lens surface 621 has a convex shape protruding toward the (−Z) side, and the second lens surface 622 has a convex shape protruding toward the (+ Z) side. When viewed along the X direction, each element lens 620 has a rectangular shape (see FIG. 3). Thus, the element lens 620 is a cylindrical lens having power only in the X direction, and the split lens unit 62 is a so-called cylindrical lens array (or cylindrical fly-eye lens).

The first lens surface 621 and the second lens surface 622 are symmetrical with respect to a surface perpendicular to the optical axis J1. The first lens surface 621 is disposed at the focal point of the second lens surface 622, and the second lens surface 622 is disposed at the focal point of the first lens surface 621. That is, the focal lengths of the first lens surface 621 and the second lens surface 622 are the same. The focal length of the first lens surface 621 and the second lens surface 622 is f _h , the refractive index of the element lens 620 is n _h , and the length L _h of the element lens 620 in the Z direction is (f _h · n _h ). expressed. The parallel light incident on the element lens 620 is collected on the second lens surface 622. When it is necessary to avoid damage or deterioration of the second lens surface 622 due to light collection, the length L _h of the element lens 620 in the Z direction is a value slightly deviated from (f _h · n _h ). There may be. The plurality of element lenses 620 stacked in the X direction may be formed as a continuous member, or the plurality of element lenses 620 formed individually may be joined to each other.

  When viewed along the Y direction, light incident on the split lens unit 62 is split by the plurality of element lenses 620 in the X direction. At this time, parallel light from each light source unit 4 enters the first lens surface 621 of each element lens 620, and images of the plurality of light sources 41 are formed in the vicinity of the second lens surface 622. These images are arranged in the arrangement direction of the element lenses 620. In FIG. 4, only light rays incident on one element lens 620 are illustrated. Light (a plurality of light beams) emitted from each light source unit 4 and divided by the plurality of element lenses 620 is emitted from the second lens surface 622 so that the principal ray is parallel to the optical axis J1 (Z direction). . The light beam emitted from each element lens 620 is incident on the optical path length difference generation unit 61 while spreading.

  The optical path length difference generating unit 61 includes a plurality of light transmitting units 610 arranged closely at a constant pitch in a direction perpendicular to the optical axis J1 and along the light source array plane (here, the X direction). In the example of FIG. 2, the number of light transmitting parts 610 in the optical path length difference generation unit 61 is one less than the number of element lenses 620 in the split lens part 62. Further, the arrangement pitch of the light transmitting portions 610 is equal to the arrangement pitch of the element lenses 620. Each translucent portion 610 is (ideally) in the form of a block having a plane perpendicular to the X direction, the Y direction, and the Z direction. In the plurality of translucent portions 610 arranged in a line in the X direction, the lengths in the X direction and the Y direction are the same, and the lengths in the Z direction, that is, the direction along the optical axis J1, are different from each other. As described above, the plurality of light transmitting portions 610 have different optical path lengths. In the optical path length difference generation unit 61 in FIG. 2, the length in the Z direction is smaller as the light transmission unit 610 located on the (+ X) side among the plurality of light transmission units 610. The length of the plurality of translucent portions 610 in the optical axis J1 direction does not necessarily need to be sequentially increased (or shortened) along the X direction, and may be any uneven shape. In the present embodiment, the plurality of light transmitting parts 610 in the optical path length difference generating part 61 are formed of the same material as a continuous member. In the optical path length difference generation unit 61, a plurality of individually formed light transmission units 610 may be joined to each other.

  The split lens unit 62 and the optical path length difference generating unit 61 are arranged close to each other in the Z direction, and a plurality of element lenses 620 and a plurality of light transmitting units 610 except for the most (+ X) side element lens 620 in the X direction. Are arranged at the same position. Therefore, the plurality of light beams that have passed through these element lenses 620 are incident on the plurality of light transmitting portions 610, respectively. Specifically, as shown in FIG. 4, the light beams emitted from the second lens surfaces 622 of these element lenses 620 are arranged at the same position in the X direction on the (−Z) side. Is incident on an incident surface 611. The luminous flux passes through the light transmitting part 610 and is emitted from the emission surface 612 which is the (+ Z) side surface. Note that the light beam that has passed through the most (+ X) side element lens 620 does not pass through any of the light transmitting portions 610.

Actually, when the split lens unit 62 and the optical path length difference generation unit 61 satisfy the conditions described later, the width of the light beam emitted from the emission surface 612 of each light transmission unit 610 is related to the light transmission unit 610 in the X direction. , That is, smaller than the arrangement pitch of the translucent portions 610. Thus, the edge of the light flux the transparent portion 610 (i.e., an end of the X-direction, primarily the edge of the incident surface 611 and exit surface 612.) In Kaka Rukoto is prevented or suppressed. In the optical path length difference generation unit 61, the same number of light transmission units 610 as the number of element lenses 620 in the split lens unit 62 may be provided. In this case, the light that has passed through the plurality (all) of the element lenses 620 is incident on the plurality of light transmitting portions 610, respectively.

As shown in FIGS. 2 and 3, the light beam that has passed through each light transmitting portion 610 travels toward the condensing lens portion 63. The condensing lens unit 63 includes two cylindrical lenses 632a and 632b. The cylindrical lens 632a is only has power X-direction, it is arranged in the by the focal length f _C of the second lens surface 622 of the plurality of element lenses 620 (+ Z) spaced side position. In other words, the second lens surface 622 of each element lens 620 is disposed at the front focal position of the cylindrical lens 632a. Further, the irradiation surface 320 disposed on the optical axis J1 is disposed at a position away from the cylindrical lens 632a to the (+ Z) side by the focal length f _{C of} the cylindrical lens 632a. That is, the irradiation surface 320 is disposed at the rear focal position of the cylindrical lens 632a. The cylindrical lens 632b is disposed between the cylindrical lens 632a and the irradiation surface 320, and has power only in the Y direction. Cylindrical lens 632b is disposed in the focal distance _{f L} only away from the irradiation surface 320 (-Z) side position.

  As shown in FIG. 2, when viewed along the Y direction, the plurality of light beams emitted from the plurality of element lenses 620 are converted into parallel light by the cylindrical lens 632 a and are superimposed on the irradiation surface 320. That is, the irradiation region 50 of light from the plurality of element lenses 620 (that is, a plurality of light beams that have passed through the plurality of light transmitting portions 610) is entirely overlapped. 2 and 3, the irradiation region 50 is indicated by a thick solid line, and the irradiation region 50 has a certain width with respect to the X direction. As described above, since the plurality of light beams emitted from the plurality of element lenses 620 pass through different light transmitting portions 610, the optical paths to the plurality of light beams between the split lens unit 62 and the irradiation surface 320 are provided. A length difference occurs. Therefore, interference fringes are suppressed (or prevented) from occurring on the irradiation surface 320 due to interference of light divided by the plurality of element lenses 620. That is, as shown in the upper part of FIG. 5, the light intensity distribution in the X direction is uniform on the irradiation surface 320. In each combination of two light transmitting portions 610 among the plurality of light transmitting portions 610, the difference in the optical path length of the light flux passing through the two light transmitting portions 610 is the coherence of the laser light emitted from the light source portion 4. It is preferable that it is more than a distance.

  As shown in FIG. 3, when viewed along the X direction, the light incident on the split lens unit 62 from the light source unit 40 remains as parallel light, and the split lens unit 62, the optical path length difference generation unit 61, and the cylindrical lens. The light passes through 632a and is guided to the cylindrical lens 632b. Then, the light emitted from the cylindrical lens 632 b is collected on the irradiation surface 320. Therefore, on the irradiation surface 320, the irradiation region 50 of the light from each element lens 620 has a line shape extending in the X direction. As a result, it is a set of light that has passed through the plurality of element lenses 620, and a cross section on the irradiation surface 320 (that is, a light beam cross section perpendicular to the optical axis J1; the same applies hereinafter) extends in the X direction. The line illumination light is obtained. The lower part of FIG. 5 shows the intensity distribution of the line illumination light in the Y direction. In the light irradiation device 31, the functions of the two cylindrical lenses 632a and 632b may be realized by one spherical lens, or a spherical lens and a cylindrical lens may be combined.

  As described above, in the light irradiation device 31 of FIG. 2, laser light is emitted from the plurality of light source units 4 toward the split lens unit 62. Thereby, compared with the light irradiation apparatus in which only one light source part 4 is used, high intensity | strength line illumination light can be obtained. In addition, since the phases of the laser beams from the plurality of light source units 4 are different from each other, this is combined with the provision of optical path length differences to the plurality of light beams passing through the plurality of element lenses 620 by the plurality of light transmitting units 610. Thus, the uniformity of the intensity distribution of the line illumination light on the irradiation surface 320 can be further improved. Note that, depending on the design of the light irradiation device 31, by slightly shifting (defocusing) the irradiation surface 320 from the rear focal position of the cylindrical lens 632a, the width of the bright part of the interference fringes on the irradiation surface 320 is increased. You may reduce the contrast in line illumination light.

Here, conditions for more reliably preventing interference fringes from occurring on the irradiation surface 320 will be described with reference to FIG. If the refractive index of the optical path length difference generation unit 61 is n _s , and the difference in length in the Z direction between two light transmission units 610 adjacent to each other in the X direction is t _so , the optical path length difference between the two light transmission units 610. Δz _s is expressed by Equation 1. However, in Equation 1, the refractive index in air is 1.

(Equation 1)
Δz _s = (n _s −1) · t _so

In the light irradiation device 31, when the optical path length difference Δz _s is equal to or greater than the coherence distance L _c of the laser light emitted from the light source unit 4, that is, by satisfying Equation 2, the plurality of element lenses 620 Interference fringes are more reliably prevented on the irradiation surface 320 due to the interference of the divided light.

(Equation 2)
L _c ≦ (n _s −1) · t _so

  Note that the greater the difference in optical path length of light passing through each combination of the two light transmitting parts 610, the lower the coherence, so the difference in optical path length is the coherence of the laser light emitted from the light source part 4. Even if it is less than the distance, if it is a relatively long distance (for example, ½ or more of the coherence distance), the influence of the interference fringes is reduced to some extent. Therefore, the optical path length difference in each combination of the two translucent portions 610 may be appropriately set according to the uniformity (contrast value) required for the intensity distribution of the line illumination light.

  By the way, when the light that has passed through each element lens 620 of the split lens unit 62 is applied to the edge of the light transmitting unit 610 (such as a boundary between the light transmitting units 610) in the optical path length difference generating unit 61, the light is scattered and irradiated. The uniformity of the light intensity distribution on the surface 320 decreases. A condition for preventing the light beam emitted from each element lens 620 from being applied to the edge of the translucent portion 610 will be described with reference to FIG.

As described above, in the light irradiation device 31, the number of the light transmitting parts 610 in the optical path length difference generation unit 61 is one less than the number of the element lenses 620 in the split lens part 62 (see FIG. 2). Therefore, the length in the Z direction among the plurality of light transmitting portions 610 is set such that the number of light transmitting portions 610 in the optical path length difference generating portion 61 is N _s or the number of element lenses 620 in the divided lens portion 62 is N _h. There the length t _s of the largest transparent portion 610 is expressed by equation (3).

(Equation 3)
t _s = N _s · t _so = (N _h −1) · t _so

On the other hand, among the plurality of light source units 4, each element lens 620 from the light source unit 4 has the maximum incident angle (angle formed with respect to the Z direction when viewed along the Y direction) of the laser light to the split lens unit 62. The light incident on the second lens surface 622, which is the exit surface of the element lens 620, deviates in the X direction from the optical axis J0 of the element lens 620 (indicated by a one-dot chain line in FIG. 4). Concentrate at the position. Specifically, the incident angle (maximum incident angle) of the light is θ _i , and the focal lengths of the first lens surface 621 and the second lens surface 622 are f _h , and the light is condensed on the second lens surface 622. The distance in the X direction between the point and the optical axis J0 is (f _h · tan θ _i ). In the light irradiation device 31 of FIG. 2, the plurality of light source units 4 are arranged so as to be perpendicular to the X direction and symmetric with respect to the plane including the optical axis J1 of the irradiation optical system 5. A condensing point separated from the optical axis J0 by the same distance is formed on both the (+ X) side and the (−X) side of J0. Therefore, the width w _h in the X direction in the second lens surface on 622 of the light incident from all the light source unit 4 to the respective element lenses 620 is expressed by Equation 4.

(Equation 4)
w _h = 2f _h · tan θ _i

Further, the divergence angle (half angle) θ _d of the light passing through the condensing point does not depend on the incident angle of the light from the light source unit 4, and the arrangement pitch of the element lenses 620 (and the translucent unit 610) is p. , Represented by equation (5).

(Equation 5)
θ _d = tan ⁻¹ (p / 2f _h )

The divergence angle (half angle) θ ′ _d of the light inside the optical path length difference generation unit 61 is expressed by Equation 6.

(Equation 6)
θ ′ _d = sin ⁻¹ (sin θ _d / n _s )

Therefore, the width in the Z direction of the gap between the second lens surface 622 of the split lens unit 62 and the incident surface 611 of the optical path length difference generating unit 61 is d _s , and the translucent unit 610 having the largest length in the Z direction. The width w _{s in} the X direction of the light beam on the exit surface 612 is expressed by Equation 7.

(Equation 7)
w _s = w _h +2 (d _s · tan θ _d + t _s · tan θ ′ _d )

Actually, so-called chamfering may be performed on the light-transmitting portion 610 so as to cut the corner portion. In such a case, on the emission surface 612 of the light-transmitting portion 610, the edge and the vicinity thereof are not provided. There will be ineffective areas. The width of the ineffective area in the X direction is, for example, greater than 0 and 100 μm or less. The predetermined width in the X direction of the non-effective region as p _o, the width p of the X direction of the effective region on the exit surface 612 of the translucent portion 610 'is expressed by the number 8.

(Equation 8)
p '= p-2p _o

  Therefore, the condition for preventing the light beam that has passed through each element lens 620 of the split lens unit 62 from passing only the effective area of the exit surface 612 of the light transmitting unit 610 and scattering the light beam in the vicinity of the edge is as follows. , Represented by Equation (9).

(Equation 9)
w _s ≦ p ′

In the light irradiation device 31 that satisfies Equation 9, light incident on the light transmission unit 610 can be prevented from being applied to the edge of the light transmission unit 610, and the light irradiated on the irradiation surface 320 by the light irradiation device 31. The uniformity of the intensity distribution can be ensured more reliably. Further, loss of light amount due to light scattering at the edge of the light transmitting portion 610 can also be prevented. As described above, since the width p _o in the X direction of the non-active area is greater than 0, the light irradiation device 31 satisfies Equation 9, in the arrangement direction of the plurality of light transmitting portions 610, a plurality of light-transmitting portions 610 It can be said that the width of the light emitted from the respective emission surfaces 612 is smaller than the pitch of the plurality of light transmitting portions 610.

As is apparent from Equation 7 and Equation 9, as the maximum length t _s of the transparent portion 610 is small, it is easy to satisfy the conditions shown in Formula 9. As described above, in the optical path length difference generation unit 61, the same number of light transmission units 610 as the number of element lenses 620 in the split lens unit 62 can be provided. However, since the maximum length t _s of the transparent portion 610 is dependent on the number of the transparent portion 610, in the viewpoint of easily satisfying the conditions shown in Equation 9, the number of the light-transmitting portion 610, the number of element lenses 620 Preferably less than one.

  6 and 7 are diagrams showing another example of the light irradiation device 31. FIG. 6 shows the configuration of the light irradiation device 31 viewed along the Y direction, and FIG. 7 shows the configuration of the light irradiation device 31 viewed along the X direction.

  In the light irradiation device 31 of FIG. 6, each light source unit 4 of the light source unit 40 includes a prism 43, a cylindrical lens 44, and a cylindrical lens 45 in addition to the light source 41 and the collimator lens 42. The light sources 41 of the plurality of light source units 4 are arranged in the X direction on a light source arrangement surface parallel to the ZX plane. Laser light emitted from each light source 41 is collimated by the collimator lens 42 and deflected by the prism 43 and travels toward the split lens unit 62 of the irradiation optical system 5. In the light source unit 40, a plurality of light sources 41 are emitted by the plurality of light source units 4 so that laser beams are emitted from different directions along the light source array surface toward the same position (divided lens unit 62) of the irradiation optical system 5. The apex angle of the prism 43 is changed according to the position in the X direction. Note that the prism 43 is omitted in the light source unit 4 at the center in the X direction.

  As shown in FIGS. 6 and 7, the cylindrical lenses 44 and 45 have power only in the Y direction. The cylindrical lenses 44 and 45 are provided between the prism 43 and the split lens unit 62. The cylindrical lens 44 is provided for each light source unit 4, and the cylindrical lens 45 is shared by the plurality of light source units 4. A spatial filter 46 is provided between the cylindrical lens 44 and the cylindrical lens 45. The spatial filter 46 is a slit plate, and a long slit 461 is formed in the X direction. As shown in FIG. 7, when viewed along the X direction, the laser light that has passed through the cylindrical lens 44 is condensed in the vicinity of the slit 461 of the spatial filter 46, and the light that has passed through the slit 461 is reflected by the cylindrical lens 45. Is incident on. The light that has passed through the cylindrical lens 45 enters the (−Z) side surface of the split lens unit 62.

  6 and FIG. 7, the split lens unit shown in FIGS. 2 and 3 is that the first lens surface 621 and the second lens surface 622 of each element lens 620a are both part of a spherical surface. 62. Also in the split lens unit 62, the first lens surface 621 of the element lens 620a is disposed at the focal point of the second lens surface 622, and the second lens surface 622 is disposed at the focal point of the first lens surface 621. That is, the focal lengths of the first lens surface 621 and the second lens surface 622 are the same. The structure and arrangement of the optical path length difference generation unit 61 are the same as those of the optical path length difference generation unit 61 in FIG.

As shown in FIG. 6, when viewed along the Y direction, the light incident on the split lens unit 62 is split in the X direction by a plurality of element lenses 620a. The plurality of light beams that have passed through the plurality of element lenses 620a excluding the most (+ X) side element lens 620a are incident on the plurality of light transmitting portions 610 of the optical path length difference generation unit 61, respectively. The light that has passed through the plurality of light transmitting parts 610 and the light that has passed through the most (+ X) side element lens 620 a are incident on the condenser lens part 63. The condenser lens unit 63 has a condenser lens 631. Condenser lens 631 is disposed on the second lens surface 622 (see FIG. 7) position apart along the optical axis J1 from the plurality of element lenses 620a by its focal length _{f C.} In other words, the second lens surface 622 of each element lens 620a is disposed on the front focal plane of the condenser lens 631. The irradiation surface 320 disposed on the optical axis J1 is disposed at a position separated from the condenser lens 631 along the optical axis J1 by the focal length f _{C of} the condenser lens 631. That is, the irradiation surface 320 coincides with the rear focal plane of the condenser lens 631. The plurality of light beams emitted from the plurality of element lenses 620a are converted into parallel light by the condenser lens 631 and superimposed on the rear focal plane of the condenser lens 631. That is, the irradiation areas 50 of the light (plural light beams) from the plurality of element lenses 620a are overlapped as a whole.

  As shown in FIG. 7, when viewed along the X direction, the light emitted from the cylindrical lens 45 of the light source unit 40 is condensed on the first lens surface 621 of the plurality of element lenses 620a, and the second lens. The light is emitted from the surface 622 as parallel light parallel to the optical axis J1. Light from the plurality of element lenses 620a is condensed on the rear focal plane (irradiation surface 320) of the condenser lens 631 by the condenser lens 631. Thereby, the line illumination light in which the cross section on the irradiation surface 320 becomes a line shape extending in the X direction is obtained.

  As described above, also in the light irradiation device 31 of FIG. 6, high intensity line illumination light can be obtained by emitting laser light from the plurality of light source units 4 toward the split lens unit 62. . In addition, by using a plurality of light source units 4, a line on the irradiation surface 320 is coupled with a plurality of light transmitting units 610 combined with providing a plurality of light beams passing through a plurality of element lenses 620 a with optical path length differences. The uniformity of the intensity distribution of the illumination light can be improved. Furthermore, also in the light irradiation device 31 of FIG. 6, by satisfying the condition of Equation 9, the light emitted from the respective emission surfaces 612 of the plurality of light transmitting portions 610 is arranged in the arrangement direction of the plurality of light transmitting portions 610. The width is smaller than the pitch of the plurality of light transmitting parts 610. Thereby, it is possible to prevent the light incident on the light transmitting part 610 from being applied to the edge of the light transmitting part 610, and to improve the uniformity of the intensity distribution of the light irradiated on the irradiation surface 320 by the light irradiation device 31. , Can be ensured more reliably.

  FIG. A is a view showing the intensity distribution of light in the Y direction on the irradiation surface 320. FIG. Assuming a light source unit of a comparative example that omits the spatial filter 46, depending on the type or state of the light source, the light intensity distribution in the Y direction on the irradiated surface is adjacent to the light intensity peak required as line illumination light. Thus, unnecessary light intensity peaks such as side lobes may occur. FIG. In A, an unnecessary light intensity peak is indicated by a broken line. On the other hand, in the light source unit 40 of FIG. 3, by providing the spatial filter 46, it becomes possible to exclude an unnecessary light intensity peak (that is, to shape the light irradiated to the irradiation surface 320). Obtaining preferred line illumination light is realized.

  In the light source unit 40 of FIG. 6, since the plurality of light source units 4 are attached to a support member (not shown), the plurality of light sources 41 can be efficiently cooled. Further, by using the prism 43, the light source 41 and the collimator lens 42 can be arranged in all the light source units 4 so that the optical axes of the light source 41 and the collimator lens 42 are parallel to the Z direction. As a result, in the plurality of light source units 4, the light source unit of FIG. 2 in which the light source 41 and the collimator lens 42 are arranged so that the optical axes of the light source 41 and the collimator lens 42 are inclined at various angles with respect to the Z direction. Compared to 40, the support member can be easily manufactured. The light collimation is not essential in the X direction, and the light from the light source unit 4 may enter the split lens unit 62 while slightly diverging or converging in the X direction. FIG. In B, the light irradiation apparatus 31 which changed the cylindrical lens 44 of FIG. 6 into the spherical lens 44a is shown. FIG. The appearance of the light irradiation device 31 shown in B along the X direction is the same as in FIG.

  By the way, in the split lens unit 62 of FIG. 3 using the element lens 620 which is a cylindrical lens, depending on the accuracy in manufacturing the split lens unit 62, the first lens surface 621 and the second lens surface when viewed along the X direction. Variation in parallelism (wedge component) with 622 may increase in the plurality of element lenses 620. In this case, the plurality of light beams that have passed through the plurality of element lenses 620 are inclined in different directions with respect to the optical axis J1 and enter the condenser lens unit 63, and the irradiation region 50 is formed on the irradiation surface 320. May shift in the Y direction. On the other hand, in the split lens unit 62 of FIG. 7, a spherical lens that is easy to mold with high accuracy is used as the element lens 620a, so that the irradiation region 50 is irradiated onto the irradiation surface 320 by the light flux that has passed through the plurality of element lenses 620a. Can be made approximately coincident with the Y direction. The above-described method using each of the spatial filter 46, the prism 43, and the element lens 620a may be individually employed in another light irradiation device 31 (and a light irradiation device 31a described later).

  9 and 10 are diagrams showing a configuration of a light irradiation apparatus 31a according to the second embodiment of the present invention. FIG. 9 shows a configuration of the light irradiation device 31a viewed along the Y direction, and FIG. 10 shows a configuration of the light irradiation device 31a viewed along the X direction.

  9 and 10 includes a light source unit 40 and an irradiation optical system 5a. The light source unit 40 has the same structure as the light source unit 40 of FIG. Therefore, in the light source unit 40, laser light is emitted by the plurality of light source units 4 from the different directions along the light source array surface toward the same position (divided lens unit 62 described later) on the irradiation optical system 5 a.

  The irradiation optical system 5a includes an optical path length difference generation unit 61, a split lens unit 62, a condensing lens unit 63, and an intermediate zoom unit 64a. In the irradiation optical system 5a, from the light source unit 40 toward the irradiation surface 320, the divided lens unit 62, the intermediate zoom unit 64a, the optical path length difference generation unit 61, and the condensing lens unit 63 are arranged in this order in the order of the optical axis J1. It is arranged along. The collimated laser beams from the plurality of light source units 4 enter the split lens unit 62. As shown in FIG. 11, in the split lens unit 62, a plurality of element lenses 620 are arranged in the X direction perpendicular to the optical axis J1 of the irradiation optical system 5a and along the light source arrangement surface.

  When viewed along the Y direction, light incident on the split lens unit 62 is split by the plurality of element lenses 620 in the X direction. At this time, parallel light from each light source unit 4 enters the first lens surface 621 of each element lens 620, and images of the plurality of light sources 41 are formed in the vicinity of the second lens surface 622. These images are arranged in the arrangement direction of the element lenses 620. In FIG. 11, only light rays incident on one element lens 620 are illustrated.

  The light (plural light beams) divided by the plurality of element lenses 620 is emitted from the second lens surface 622 so that the principal ray is parallel to the optical axis J1. The light beam emitted from each element lens 620 spreads and enters the lens 643 of the intermediate zoom unit 64a shown in FIG. 9 and enters the optical path length difference generation unit 61 via the lenses 643 and 644. In the optical path length difference generation unit 61, a plurality of light transmission units 610 are arranged in the X direction perpendicular to the optical axis J1 of the irradiation optical system 5a and along the light source arrangement surface. The arrangement pitch of the light transmitting portions 610 is larger than the arrangement pitch of the element lenses 620.

  The intermediate zooming unit 64a constitutes an afocal optical system, specifically, a double-sided telecentric optical system, and the principal ray is incident in a state parallel to the optical axis J1, and the principal ray is parallel to the optical axis J1. In this state, the light is incident on the optical path length difference generation unit 61. At this time, the intermediate zooming unit 64a converts the image of the second lens surface 622 that is the exit surface of the plurality of element lenses 620 (specifically, the image of the plurality of light sources 41 on the second lens surface 622) to the optical path length difference. It is enlarged and formed inside or near the generator 61.

  Specifically, the magnification by the intermediate zooming unit 64 a is equal to a value obtained by dividing the arrangement pitch of the light transmitting units 610 in the optical path length difference generation unit 61 by the arrangement pitch of the element lenses 620 in the divided lens unit 62. Accordingly, the light (plural light beams) that has passed through the plurality of element lenses 620 is incident on the plurality of light transmitting portions 610 via the intermediate magnification varying portion 64a that constitutes the magnifying optical system. At this time, images of the second lens surfaces 622 of the plurality of element lenses 620 are formed in or near the plurality of light transmitting portions 610, respectively. In addition, the divergence angle of the light beam emitted from each element lens 620 in the translucent portion 610 is smaller than the divergence angle in the vicinity of the second lens surface 622 of the element lens 620 according to the magnification. As a result, the light flux is less likely to be applied to the edge of the light transmitting part 610 (for example, the boundary with the adjacent light transmitting part 610). The light flux that has passed through each light transmitting portion 610 travels toward the condensing lens portion 63. The plurality of light beams emitted from the plurality of light transmitting portions 610 are converted into parallel light by the condenser lens 631 of the condenser lens portion 63 and are superimposed on the irradiation surface 320. That is, the irradiation areas 50 of light (a plurality of light beams) from the plurality of light transmitting portions 610 are entirely overlapped.

  As shown in FIG. 10, when viewed along the X direction, the light incident on the optical path length difference generation unit 61 from the light source unit 40 through the split lens unit 62 and the intermediate zoom unit 64 a remains as parallel light. Then, the light passes through the plurality of light transmitting portions 610 and is guided to the condenser lens 631. The light emitted from the condenser lens 631 is collected on the irradiation surface 320. Therefore, on the irradiation surface 320, the irradiation region 50 of light from each element lens 620 (translucent portion 610) has a line shape extending in the arrangement direction. That is, the cross section of the light irradiated onto the irradiation surface 320 by the light irradiation device 31a becomes a line extending in the X direction, and line illumination light is obtained.

  In the light irradiation device 31a, the condenser lens 631 is a spherical lens. For example, by adding a cylindrical lens having power only in the Y direction to the condenser lens unit 63, a desired width in the Y direction on the irradiation surface 320 can be obtained. A line illumination light may be obtained. When the light source 41 is a high-power semiconductor laser and the laser light emitted from the light source 41 is multimode in one direction, the direction in which the single mode is set is the arrangement of the element lenses 620 in the split lens unit 62. It is preferable to match the direction perpendicular to the direction (Y direction). This prevents the width of the line illumination light in the Y direction from being widened on the irradiation surface 320.

  By the way, in the light irradiation apparatus 31 shown in FIG. 2 and FIG. 6, it is necessary to make the arrangement pitch of the translucent part 610 in the optical path length difference generation part 61 equal to the arrangement pitch of the element lenses 620 in the divided lens part 62. A small split lens can be easily manufactured with high accuracy by using photolithography. However, the optical path length difference generating unit in which the lengths of the plurality of translucent portions in the optical axis direction are different from each other can be It is difficult to use lithography. Therefore, it is necessary to produce the optical path length difference generation unit by complicated work such as machining.

  On the other hand, in the light irradiation device 31a of FIG. 9, an intermediate zoom unit 64a that constitutes the magnifying optical system is disposed between the split lens unit 62 and the optical path length difference generation unit 61. As a result, the optical path length difference generation unit 61 can be made larger than the split lens unit 62 with respect to the arrangement direction of the light transmission parts 610 (X direction in FIG. 9), and the optical path length difference generation part 61 is easily manufactured. can do. In the light irradiation device 31 shown in FIGS. 2 and 6, the configuration can be simplified by omitting the intermediate zooming portion 64 a, and thus the light irradiation device 31 can be easily downsized.

  In the light irradiation device 31 a, laser light is emitted from the plurality of light source units 4 toward the split lens unit 62. Thereby, compared with the light irradiation apparatus in which only one light source part 4 is used, high intensity | strength line illumination light can be obtained. In addition, since the phases of the laser beams from the plurality of light source units 4 are different from each other, this is combined with the provision of optical path length differences to the plurality of light beams passing through the plurality of element lenses 620 by the plurality of light transmitting units 610. Thus, the uniformity of the intensity distribution of the line illumination light on the irradiation surface 320 can be further improved.

  In the light irradiation device 31a, the intermediate magnification unit 64a forms an image of the exit surface of the plurality of element lenses 620 in or near the plurality of light transmitting units 610, and as the image is enlarged, The divergence angle of the light beam emitted from each element lens 620 in the translucent portion 610 is smaller than the divergence angle in the element lens 620. As a result, it is possible to easily suppress the light flux from being applied to the edge of the light transmitting portion 610, and to ensure the uniformity of the intensity distribution of the light irradiated onto the irradiation surface 320 by the light irradiation device 31a. can do.

  12 and 13 are diagrams showing another example of the light irradiation device 31a. FIG. 12 shows the configuration of the light irradiation device 31a viewed along the Y direction, and FIG. 13 shows the configuration of the light irradiation device 31a viewed along the X direction. In the light irradiation device 31a shown in FIGS. 12 and 13, lenses 53 and 54 are added between the optical path length difference generation unit 61 and the condensing lens unit 63 as compared with the light irradiation device 31a of FIGS. 9 and 10. Is different. Other configurations are the same as those of the light irradiation device 31a of FIGS. 9 and 10, and the same components are denoted by the same reference numerals.

  The lenses 53 and 54 constitute a reduction optical system (for example, both-side telecentric optical system), and an image of the second lens surface 622 of the plurality of element lenses 620 (see FIG. 11) in or near the optical path length difference generation unit 61. In detail, the reduction relay is performed on the images of the plurality of light sources 41 on the second lens surface 622. The light emitted from the lens 54 enters the condenser lens 631 of the condenser lens unit 63, and a line-shaped irradiation region 50 is formed on the irradiation surface 320.

  As described above, the light beam emitted from each element lens 620 has a relatively small divergence angle in the light transmitting portion 610, so that the light irradiation device 31a can easily apply the light flux to the edge of the light transmitting portion 610. It is suppressed. In this case, in order to obtain line illumination light having a certain length in the X direction on the irradiation surface 320, it is necessary to provide the condenser lens 631 having a long focal length in the light irradiation device 31a of FIG. The overall length of the irradiation optical system 5a is increased. On the other hand, in the light irradiation apparatus 31a of FIG. 12, the lenses 53 and 54 constituting the reduction optical system are provided between the optical path length difference generation unit 61 and the condensing lens unit 63, so that the irradiation optical system 5a. Can be made relatively short, and the light irradiation device 31a can be downsized.

  14 and 15 are diagrams showing another example of the light irradiation device 31a. FIG. 14 shows the configuration of the light irradiation device 31a viewed along the Y direction, and FIG. 15 shows the configuration of the light irradiation device 31a viewed along the X direction. The light irradiation device 31a shown in FIGS. 14 and 15 is different from the light irradiation device 31a shown in FIGS. 9 and 10 in that a polarizing beam splitter 55, a quarter wavelength plate 56, and a reflection unit 65 are added. To do. Other configurations are the same as those of the light irradiation device 31a of FIGS. 9 and 10, and the same components are denoted by the same reference numerals.

  In the light irradiation device 31a of FIG. 14, from the (−Z) side toward the (+ Z) direction, the reflecting portion 65, the optical path length difference generating portion 61, the quarter wavelength plate 56, and the lens 644 of the intermediate zooming portion 64a. These components are arranged in the order of 643, the polarization beam splitter 55, and the condenser lens unit 63. The light source unit 40 is disposed on the (+ X) side of the polarization beam splitter 55, and the split lens unit 62 is disposed between the light source unit 40 and the polarization beam splitter 55. In the light source unit 40, laser light is emitted from the plurality of light source units 4 arranged approximately in the Z direction toward the split lens unit 62 along different directions parallel to the light source array surface.

  In the split lens unit 62, a plurality of element lenses 620 (see FIG. 11) are arranged in the Z direction perpendicular to the optical axis between the light source unit 40 and the polarization beam splitter 55 and along the light source array plane. Light incident on 62 is split in the Z direction. The light that has passed through the split lens unit 62 enters the polarization beam splitter 55 in a state in which the principal ray is parallel to the X direction. The polarization beam splitter 55 separates the p-polarized component and the s-polarized component. Most of the light that enters the polarization beam splitter 55 from the light source unit 40 via the split lens unit 62 is an s-polarized component, and the light is reflected by the polarization beam splitter 55 and is directed to the lens 643 of the intermediate magnification unit 64a. Head. At this time, the arrangement direction of the plurality of light beams emitted from the plurality of element lenses 620 is converted into the X direction. In other words, the chief ray of the light traveling from the polarization beam splitter 55 to the intermediate zoom unit 64a is parallel to the Z direction.

  In the intermediate zooming unit 64a, a double-sided telecentric optical system is configured, and the optical path length in which the principal ray is incident in a state parallel to the optical axis J1 (Z direction) and the principal ray is parallel to the optical axis J1. The light is incident on the difference generator 61. Actually, the light (a plurality of light fluxes) that has passed through the plurality of element lenses 620 passes through the polarization beam splitter 55, the intermediate magnification varying portion 64a, and the quarter wavelength plate 56, and thus the plurality of light transmitting portions arranged in the X direction. An image of the second lens surface 622 of each of the plurality of element lenses 620 (an image of the light source 41) is formed to be enlarged inside or in the vicinity of the plurality of light transmitting portions 610 in the optical path length difference generation unit 61. Is done. As described above, the arrangement direction of the element lenses 620 of the split lens unit 62 corresponds to the arrangement direction of the light transmission units 610 of the optical path length difference generation unit 61 via the polarization beam splitter 55.

  The reflection unit 65 includes a reflection film 651 a formed by coating on the (−Z) side surface of the optical path length difference generation unit 61. The light beam incident on the incident surface 611 (see FIG. 4) on the (+ Z) side of each light transmitting portion 610 is reflected by the reflection film 651a on the emission surface 612 on the (−Z) side. The light is emitted from the incident surface 611. That is, the light beam incident on the incident surface 611 of each light transmitting portion 610 reciprocates in the Z direction inside the light transmitting portion 610 and is emitted from the incident surface 611 in the (+ Z) direction. The reflective film 651a on the emission surface 612 substantially turns back the light emitted from the plurality of emission surfaces 612 of the plurality of light transmitting portions 610 (that is, rotates the traveling direction by 180 degrees). Each is incident on the surface 612. The image of the second lens surface 622 of the element lens 620 is preferably formed in the vicinity of the emission surface 612 (in the vicinity of the reflective film 651a) of the light transmitting portion 610.

  The light emitted from the optical path length difference generation unit 61 in the (+ Z) direction is incident on the intermediate magnification unit 64 a via the quarter-wave plate 56. In the intermediate zooming unit 64a, the images of the exit surfaces of the plurality of element lenses 620 in or near the optical path length difference generating unit 61 are reduced and relayed. Light emitted from the lens 643 enters the polarization beam splitter 55. The light incident on the polarization beam splitter 55 from the intermediate magnification varying portion 64a becomes a p-polarized component by passing through the quarter-wave plate 56 twice by the reciprocation between the polarization beam splitter 55 and the reflection portion 65. The light passes through the polarization beam splitter 55 and enters the condenser lens 631. Then, the irradiation area 50 of the light from the plurality of element lenses 620 is superimposed on the irradiation surface 320 by the condenser lens 631.

  As described above, in the light irradiation device 31a in FIG. 14, an image obtained by enlarging the exit surfaces of the plurality of element lenses 620 is intermediate in the forward path of light between the polarization beam splitter 55 and the reflection unit 65. It is formed inside or in the vicinity of the plurality of light transmitting parts 610 by the zooming part 64a. Thereby, the optical path length difference generation unit 61 can be made larger than the split lens unit 62 with respect to the arrangement direction of the light transmitting units 610, and the optical path length difference generation unit 61 can be easily manufactured. In addition, the functions of the lenses 53 and 54 in FIG. 12 are realized by the intermediate magnification changing unit 64a in the return path in the light reciprocation, thereby omitting the lenses 53 and 54 and the total length of the light irradiation device 31a in the Z direction. Can be shortened. Further, the light beam passing through each light transmitting section 610 reciprocates the light transmitting section 610, thereby shortening the length of the optical path length difference generating section 61 in the optical axis J1 direction (for example, the optical paths in FIGS. 9 and 12). Half the length of the length difference generator 61).

  In the light irradiation device 31a of FIG. 14, it is possible to relatively reduce the loss of light quantity by using the polarization beam splitter 55 and the quarter wavelength plate 56, but depending on the design of the light irradiation device 31. Other beam splitters such as a half mirror may be used. In addition, the quarter wavelength plate 56 can be disposed at an arbitrary position between the polarization beam splitter 55 and the reflection unit 65. The same applies to other light irradiation apparatuses using the polarization beam splitter 55 and the quarter-wave plate 56. Furthermore, in the light irradiation apparatus 31a of FIG. 14, a mirror may be provided instead of the reflective film 651a. Furthermore, an optical path length difference generating unit having mirrors (reflecting surfaces) 613 arranged in a step shape as shown in FIG. 16 may be used instead of the above-described translucent element.

  17 and 18 are diagrams showing another example of the light irradiation device 31a. FIG. 17 shows the configuration of the light irradiation device 31a viewed along the Y direction, and FIG. 18 shows the configuration of the light irradiation device 31a viewed along the X direction. In the light irradiation device 31a shown in FIGS. 17 and 18, a lens 657 and a right-angle prism 658 are provided instead of the reflection film 651a in the light irradiation device 31a of FIGS. Other configurations are the same as those of the light irradiation device 31a of FIGS. 14 and 15, and the same components are denoted by the same reference numerals.

  The lens 657 of the reflection unit 65 is located at a position (−Z) away from the position where the image of the exit surface of the element lens 620 (see FIG. 11) is formed in the optical path length difference generation unit 61 by the focal length of the lens 657. Placed in. Therefore, the light beam emitted from the emission surface 612 that is the (−Z) side surface of each light transmitting portion 610 toward the lens 657 is emitted by the lens 657 to the (−Z) side as parallel light. The right-angle prism 658 is disposed at a position away from the lens 657 by the focal length of the lens 657 toward the (−Z) side. When viewed along the Y direction as shown in FIG. 17, each light ray incident on the right-angle prism 658 is reflected by one of the two surfaces 658 a and 658 b forming 90 degrees and travels toward the other surface. The light is further reflected on the other surface and travels toward the lens 657 in parallel with the path upon incidence on the right-angle prism 658. The light that enters the lens 657 from the (−Z) side enters the optical path length difference generation unit 61 while converging. Actually, the light beam emitted from the (−Z) side emission surface 612 of each light transmitting portion 610 is folded back by the reflection portion 65 and returns to the same emission path 612 after entering the same path. Further, a condensing point of the light flux is formed in or near the light transmitting portion 610.

  The light emitted from the optical path length difference generation unit 61 in the (+ Z) direction is incident on the polarization beam splitter 55 via the quarter-wave plate 56 and the intermediate magnification unit 64a. The light passes through the polarization beam splitter 55 and enters the condenser lens 631. Then, the irradiation area 50 of the light from the plurality of element lenses 620 is superimposed on the irradiation surface 320 by the condenser lens 631.

  Here, it is assumed that the parallelism of the incident surface 611 and the exit surface 612 of the light transmitting portion 610 varies for each light transmitting portion 610 when viewed along the X direction as shown in FIG. In this case, the light beam incident on the (+ Z) side incident surface 611 of each light transmitting portion 610 as parallel light parallel to the optical axis J1 is inclined with respect to the optical axis J1 from the emission surface 612 of the light transmitting portion 610. It is emitted as parallel light in the emitted direction. The luminous flux is condensed at a position shifted from the optical axis J1 on the right-angle prism 658 by the action of the lens 657. The light beam reflected by the right-angle prism 658 is converted into parallel light parallel to the emission direction by the lens 657 and is incident on the emission surface 612 of the translucent portion 610. Therefore, the light beam that has passed through the light transmitting portion 610 does not depend on the degree of parallelism of the light transmitting portion 610, and is (+ Z) from the incident surface 611 in parallel to the path when entering the light transmitting portion 610 from the (+ Z) side. ) Direction. Then, the light irradiation regions 50 from the plurality of light transmitting portions 610 are formed on the irradiation surface 320 at (substantially) the same position in the Y direction.

  As described above, in the light irradiation device 31a shown in FIGS. 17 and 18, the reflection unit 65 causes the light emitted from the emission surface 612 of each light transmission unit 610 to be parallel to the emission direction of the light. 612 is incident. Thereby, even when the parallelism (wedge component) in the plurality of light transmitting portions 610 varies, the inclinations (X of the plurality of light beams emitted from the plurality of light transmitting portions 610 in the (+ Z) direction with respect to the optical axis J1 (X The inclination when viewed along the direction) can be made to coincide with the inclination (ideally parallel to the optical axis J1) at the time of incidence on the optical path length difference generation unit 61 from the (+ Z) side. As a result, the deviation in the Y direction of the condensing position (condensing position when viewed along the X direction) on the irradiation surface 320 of the plurality of light beams that have passed through the plurality of light transmitting portions 610 is suppressed or reduced, and irradiation is performed. The width of the line illumination light on the surface 320 can be suppressed from increasing in width in the Y direction. In the reflecting portion 65, instead of the right-angle prism 658, two plane mirrors having an angle of 90 degrees with each other may be used.

  The drawing apparatus 1 and the light irradiation apparatuses 31 and 31a can be variously modified.

  In the divided lens unit 62, the plurality of element lenses 620 and 620a are not necessarily arranged at a constant pitch in the arrangement direction. For example, even if the widths of the plurality of element lenses 620 and 620a in the arrangement direction are different from each other. Good. In this case, with respect to the arrangement direction, the ratios of the widths of the respective light transmitting portions 610 in the optical path length difference generating unit 61 and the widths of the element lenses 620 and 620a of the split lens unit 62 corresponding to the light transmitting portions 610 are all The width in the arrangement direction of the plurality of light transmitting parts 610 is also changed so as to be constant in the light transmitting part 610.

  The intermediate zooming unit 64a is not necessarily a double-sided telecentric optical system, and may be configured as an enlargement optical system in which light that has passed through the plurality of element lenses 620 and 620a enters the plurality of light transmitting units 610, respectively.

  In the path of the laser light in the light irradiation devices 31, 31 a, the condensing lens unit 63 disposed on the irradiation surface 320 side with respect to the optical path length difference generation unit 61 includes a plurality of light transmitting units 610 on the irradiation surface 320. As long as it is possible to superimpose the light irradiation regions 50, it may be realized in various configurations.

  In the drawing apparatus 1, the spatial light modulator 32 disposed on the irradiation surface 320 of the light irradiation device 31, 31 a may be other than a diffraction grating type light modulator, for example, a space using a set of minute mirrors. An optical modulator may be used. In this case, an irradiation region having a relatively wide width in the Y direction may be formed on the irradiation surface 320 by the light irradiation devices 31 and 31a.

  The moving mechanism for moving the light irradiation position on the substrate 9 may be other than the moving mechanism 22 for moving the stage 21. For example, the light irradiation devices 31, 31a, the spatial light modulator 32, and the projection optical system 33 are included. It may be a moving mechanism that moves the head including the substrate 9.

  An object on which drawing is performed by the drawing apparatus 1 may be a substrate other than a semiconductor substrate or a glass substrate, or may be other than a substrate. The light irradiation devices 31 and 31 a may be used in addition to the drawing device 1.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Drawing apparatus 4 Light source part 5, 5a Irradiation optical system 9 Substrate 11 Control part 22 Movement mechanism 31, 31a Light irradiation apparatus 32 Spatial light modulator 33 Projection optical system 40 Light source unit 50 Irradiation area 61 Optical path length difference generation part 62 Split lens Part 63 Condensing lens part 64a Intermediate zooming part 65 Reflecting part 320 Irradiation surface 610 Translucent part 612 Emission surface (of translucent part) 620, 620a Element lens 622 Second lens surface J1 Optical axis

Claims (7)

A light irradiation device,
A plurality of light source units arranged on one surface, wherein the plurality of light source units emit laser light from different directions along the surface toward a predetermined position;
An irradiation optical system that is arranged at the predetermined position and guides the laser light from the light source unit to the irradiation surface along the optical axis;
With
The irradiation optical system is
A plurality of lenses arranged in an arrangement direction perpendicular to the optical axis and along the surface, and a split lens unit that divides light incident from the plurality of light source units by the plurality of lenses;
An optical path length difference generating unit that includes a plurality of light transmitting parts arranged in the arrangement direction and having different optical path lengths, and a plurality of light beams that have passed through the plurality of lenses are incident on the plurality of light transmitting parts, respectively; ,
A condensing lens unit that is disposed on the irradiation surface side of the optical path length difference generation unit in the laser beam path and overlaps the irradiation regions of the plurality of light beams from the plurality of light transmitting units on the irradiation surface; ,
With
The split lens unit and the optical path length difference generation unit are arranged close to each other,
An image of a plurality of light sources included in the plurality of light source units is formed in the vicinity of an exit surface of each of the plurality of lenses,
The plurality of light beams from the plurality of lenses are incident on the plurality of light transmitting portions while diverging in the arrangement direction,
With respect to the arrangement direction, the width of the light beam emitted from each of the exit surface of the plurality of light transmitting portions, rather smaller than the pitch of the plurality of light transmitting portions,
The width in the arrangement direction of the light flux on the emission surface of the light transmissive part having the longest length in the direction of the optical axis among the plurality of light transmissive parts is denoted by w _s ,
P ′ represents the width in the arrangement direction of the effective region on the emission surface of each of the plurality of light transmitting portions.
The width of the arrangement direction of the light flux on the exit surface of each of the plurality of lenses is expressed as w _h ,
The focal length of each of the two lens surfaces of the plurality of lenses is f _h ,
Θ _i , the incident angle of light incident on each of the plurality of lenses from the light source unit having the maximum incident angle of the laser beam to the split lens unit among the plurality of light source units .
D _{s is} the width of the gap between the exit surface of each of the plurality of lenses and the entrance surface of each of the plurality of translucent portions ;
The length of the translucent part having the longest length in the direction of the optical axis among the plurality of translucent parts is defined as _ts ,
A half angle of divergence of light passing through a condensing point on the exit surface of each of the plurality of lenses is defined as θ _d ,
The half angle of the divergence of the light inside the optical path length difference generation unit is θ ′ _d ,
The pitch of the plurality of translucent portions is p,
On the exit surface of each of the plurality of translucent portions, the width in the arrangement direction of each edge and the ineffective region existing in the vicinity thereof is defined as _po .
w _s ≦ p ′ (where w _h = 2f _h · tan θ _i , w _s = w _h +2 (d _s · tan θ _d + t _s · tan θ ′ _d ) and p ′ = p−2 p _o )
Is satisfied , the light irradiation apparatus characterized by the above-mentioned. A light irradiation device,
A plurality of light source units arranged on one surface, wherein the plurality of light source units emit laser light from different directions along the surface toward a predetermined position;
An irradiation optical system that is arranged at the predetermined position and guides the laser light from the light source unit to the irradiation surface along the optical axis;
With
The irradiation optical system is
A plurality of lenses arranged in a direction perpendicular to the optical axis and along the surface, and a split lens unit that divides light incident from the plurality of light source units by the plurality of lenses;
Optical path length difference generation in which light having a plurality of light transmitting portions arranged in a direction perpendicular to the optical axis and having different optical path lengths is incident on each of the plurality of light transmitting portions. And
An intermediate magnification unit that is disposed between the split lens unit and the optical path length difference generation unit and constitutes an enlargement optical system,
A condensing lens unit that is disposed closer to the irradiation surface than the optical path length difference generation unit in the path of the laser light, and overlaps irradiation regions of light from the plurality of light transmitting units on the irradiation surface;
A light irradiation apparatus comprising: It is a light irradiation apparatus of Claim 2, Comprising:
The light irradiating apparatus characterized in that the intermediate zooming portion constitutes a double-sided telecentric optical system. It is a light irradiation apparatus of Claim 3, Comprising:
The light irradiation apparatus, wherein the intermediate zooming unit forms an image of an exit surface of the plurality of lenses in or near the plurality of light transmitting units. A light irradiation device,
A plurality of light source units arranged on one surface, wherein the plurality of light source units emit laser light from different directions along the surface toward a predetermined position;
An irradiation optical system that is arranged at the predetermined position and guides the laser light from the light source unit to the irradiation surface along the optical axis;
With
The irradiation optical system is
A plurality of lenses arranged in a direction perpendicular to the optical axis and along the surface, and a split lens unit that divides light incident from the plurality of light source units by the plurality of lenses;
Optical path length difference generation in which light having a plurality of light transmitting portions arranged in a direction perpendicular to the optical axis and having different optical path lengths is incident on each of the plurality of light transmitting portions. And
A reflection section that transmits the light path length difference generation section and radiates light emitted from a plurality of emission faces of the plurality of light transmission sections, and makes each incident on the plurality of emission faces;
A condensing lens unit that is disposed closer to the irradiation surface than the optical path length difference generation unit in the path of the laser light, and overlaps irradiation regions of light from the plurality of light transmitting units on the irradiation surface;
A light irradiation apparatus comprising: It is a light irradiation apparatus of Claim 5, Comprising:
The light irradiation apparatus, wherein the reflection unit causes light emitted from the plurality of emission surfaces to enter the plurality of emission surfaces in parallel to an emission direction of the light. A drawing device,
The light irradiation device according to any one of claims 1 to 6,
A spatial light modulator disposed on the irradiation surface in the light irradiation device;
A projection optical system for guiding light spatially modulated by the spatial light modulator onto an object;
A moving mechanism for moving an irradiation position on the object of the spatially modulated light;
A controller that controls the spatial light modulator in synchronization with the movement of the irradiation position by the moving mechanism;
A drawing apparatus comprising:

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