Fly-eye lens, light irradiation device having the same, and method for manufacturing fly-eye lens

Abstract

The present invention provides a fly-eye lens that can be adjusted to uniformly maintain illumination over a wide exposure area more easily than conventional methods. The fly-eye lens (10) is formed by arranging a plurality of lens segments (20) in a first direction. Each lens segment (20) is formed by arranging a plurality of lenses (24) in a second direction perpendicular to the first direction. The front and back surfaces of each lens segment (20) have different optical properties. The front surface of the lens segment (20) forms a portion of the surface of the fly-eye lens (10), and the back surface of the lens segment (20) forms the remaining portion.

Description

Technical Field

[0001] The present invention relates to a fly-eye lens that makes the illumination distribution in a light irradiation area uniform, a light irradiation device including the fly-eye lens, and a method for manufacturing the fly-eye lens. Background Art

[0002] As a light source of an exposure device, a light irradiation device is used. For example, Figure 8 As shown, the light irradiation device is composed of a lamp 1 , a reflector 2 , a shutter 3 , a fly-eye lens 4 and a collimator lens 5 .

[0003] Light emitted from the lamp 1 is reflected by the reflector 2 and changed in direction, and then passes through the shutter 3 and enters the fly-eye lens 4 .

[0004] The fly-eye lens 4 has a function of making the illumination distribution of incident light on the exposure surface 6 uniform.

[0005] The light emitted from the fly-eye lens 4 is reflected by the collimator mirror 5 to become parallel light, and is irradiated onto the exposure surface 6 .

[0006] The fly-eye lens disclosed in Patent Document 1 is composed of a plurality of elongated lens segments formed by abutting and welding rectangular lenses in one direction, and is formed by arranging the lens segments in a direction perpendicular to the one direction.

[0007] This makes it difficult for gaps to form on the connection surfaces between adjacent lenses in each lens segment, and even if dirt or damage occurs on one lens, the lens unit including that lens can be easily replaced.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-9611 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, in recent years, as liquid crystal panels have become larger, the exposure area has also increased, and the overall size of the fly-eye lens has also increased. Therefore, it is becoming increasingly difficult to uniformly adjust the fly-eye lens to achieve uniform illumination across a wide exposure area.

[0013] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a fly-eye lens that can more easily adjust the illumination intensity of a wide exposure area to be uniform than before, a light irradiation device including the same, and a method for manufacturing the fly-eye lens.

[0014] Technical solutions to problems

[0015] According to one aspect of the present invention, there is provided a fly-eye lens, which is formed by arranging a plurality of lens segments in a first direction, wherein:

[0016] Each lens segment is formed by arranging a plurality of lenses in a second direction orthogonal to the first direction.

[0017] The front and back surfaces of the lens segments have different optical properties from each other.

[0018] A portion of the surface of the fly-eye lens is constituted by the surface of the lens segment, and the remaining portion is constituted by the back surface of the lens segment.

[0019] According to another aspect of the present invention, there is provided a light irradiation device including the above-mentioned fly-eye lens.

[0020] According to another aspect of the present invention, a method for manufacturing a fly-eye lens is provided, wherein a plurality of lens segments are prepared, each of which is composed of a plurality of lenses arranged in a second direction orthogonal to a first direction, and each of which has different optical properties on its front and back surfaces, and the plurality of lens segments are arranged in the first direction to manufacture the fly-eye lens, wherein:

[0021] When a plurality of lens segments are arranged, the light focusing degree of the fly-eye lens is adjusted by selecting whether the front surface or the back surface of the lens segment is arranged on the surface of the fly-eye lens.

[0022] Effects of the Invention

[0023] The fly-eye lens of the present invention utilizes lens segments with front and back surfaces having different optical properties. This allows adjustment of the illumination of the exposure area by determining whether the front or back surfaces of the lens segments are used. Consequently, the fly-eye lens of the present invention facilitates adjustment to achieve uniform illumination across a wide exposure area. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 and 2 are a perspective view (a) and a cross-sectional view (b) showing a fly-eye lens 10 according to an embodiment of the present invention.

[0025] Figure 2 It is an exploded perspective view showing the lens unit 12 .

[0026] Figure 3 1 is a diagram showing the thickness of the lens 24 and the thickness of the holding portion 26 in the lens segment 20 .

[0027] Figure 4 It is a partial cross-sectional view showing a state where the lens segment 20 is attached to the holder 22 .

[0028] Figure 5 This is a diagram showing an example in which the outer shape of the irradiation range on the irradiation surface is a "pincushion shape."

[0029] Figure 6 This is a diagram showing an example in which the outer shape of the irradiation range on the irradiation surface is a "barrel shape."

[0030] Figure 7 It is an exploded perspective view showing a modified example of the bracket 22 .

[0031] Figure 8 This is a diagram showing an example of a light irradiation device used as a light source for an exposure device or the like. DETAILED DESCRIPTION

[0032] (Structure of Fly-Eye Lens 10)

[0033] The fly-eye lens 10 according to the embodiment of the present invention will be described below. Figure 1 As shown, the fly-eye lens 10 generally includes a pair of lens units 12 and a housing 14 .

[0034] like Figure 2 As shown, each lens unit 12 includes a plurality of lens segments 20 and a holder 22 that holds the lens segments 20 arranged in a first direction (left-right direction in the figure).

[0035] Each lens segment 20 is formed by arranging a plurality of lenses 24 in a second direction (a direction perpendicular to the first direction: the vertical direction in the figure).

[0036] Each lens 24 is formed so as to have different optical properties on its front and back sides. Each lens segment 20 formed by arranging these lenses 24 has different optical properties on its front and back sides. Conceivable materials for the lenses 24 include quartz (synthetic / fused), borosilicate glass, and resin.

[0037] The so-called different optical characteristics include, for example, a lens with one side convex and the other side flat (plano-convex lens), a lens with both sides convex but different diameters (degree of curvature) (biconvex lens), etc. Figure 2 The curvature of the surface on the near-front side (front face) is relatively steep, while the curvature of the surface on the opposite side (back face) is relatively gentle.

[0038] Alternatively, the lenses 24 may be connected and arranged in the second direction by bonding, or a plurality of lenses 24 may be arranged in the second direction by pressing or bonding using low-melting-point glass.

[0039] In addition, if Figure 3 As shown, the thickness of the holding portion 26 can be formed to be thinner (a) or thicker (b) than the thickness of the lens 24. Alternatively, the thickness of the holding portion 26 can be the same as that of the lens 24.

[0040] return Figure 2 The bracket 22 is a component that holds the plurality of lens segments 20 arranged in the first direction as described above, and is formed into a quadrilateral shape by a pair of longitudinal holding frames 30, an upper lateral holding frame 32, and a lower lateral holding frame 34. The bracket 22 can be made of aluminum, stainless steel, brass, or the like.

[0041] The vertical holding frame 30 is a member disposed on the left and right sides in the longitudinal direction of the holder 22 , and is formed to have a thickness slightly thicker than the maximum thickness of the lens 24 constituting the lens segment 20 .

[0042] The upper lateral holding frame 32 is a member disposed on the upper side in the transverse direction of the bracket 22 , and the lower lateral holding frame 34 is a member disposed on the lower side in the transverse direction of the bracket 22 .

[0043] Furthermore, the upper lateral holding frame 32 and the lower lateral holding frame 34 are formed with holding grooves 42 facing inward by forming their cross sections into L-shapes, and the holding portions 26 of the lens segments 20 can be placed in the holding grooves 42 .

[0044] Furthermore, a first pressing member 46 is disposed in the retaining groove 42 of at least one of the upper lateral retaining frame 32 and the lower lateral retaining frame 34 (in this embodiment, the upper lateral retaining frame 32). This first pressing member 46 presses the mounted lens segment 20 toward the other of the upper lateral retaining frame 32 and the lower lateral retaining frame 34 (in this embodiment, the lower lateral retaining frame 34). In this embodiment, a leaf spring is used as the first pressing member 46. However, the first pressing member 46 is not limited to a leaf spring and may be any elastic member having the aforementioned function.

[0045] Furthermore, a second pressing member 48 is provided on one of the pair of vertical retaining frames 30 (in this embodiment, the right vertical retaining frame 30 in the figure). This second pressing member 48 presses the mounted lens segment 20 toward the other vertical retaining frame 30 (in this embodiment, the left vertical retaining frame 30 in the figure). In this embodiment, a leaf spring is also used as the second pressing member 48. However, the second pressing member 48 is not limited to a leaf spring; any elastic member having the aforementioned function may be used.

[0046] When the required number of lens segments 20 are arranged on the bracket 22, the lens segment 20 is pressed toward a corner (in this embodiment, the corner on the lower left side of the figure) by the pressing force of these first pressing parts 46 and the second pressing parts 48, so that the corner becomes a reference position (reference plane), and the lens segment 20 can be arranged in the correct position.

[0047] Furthermore, the bracket 22 includes a pair of clamping plates 44 that are placed overlappingly so as to abut against the holding portions 26 of the lens segment 20 placed in the holding grooves 42 of the upper and lower lateral holding frames 32 and 34. Furthermore, the clamping plates 44 may be simply plates or may be formed of an elastic material (e.g., a leaf spring) that presses the holding portions 26 of the lens segment 20 against the holding grooves 42.

[0048] Thus, the upper holding portion 26 of each lens segment 20 receiving the pressing force from the first pressing member 46 is clamped between the clamping plate 44 and the holding groove 42 (see FIG. Figure 4 ), and the retaining portion 26 on the lower side of the figure is also clamped between the clamping plate 44 and the retaining groove 42, thereby preventing each lens segment 20 from floating from the bracket 22.

[0049] The housing 14 can accommodate two lens units 12 as described above. Figure 1 As shown in (b), the lens units 12 are arranged facing each other with a predetermined distance therebetween. Furthermore, the housing 14 can be made of materials such as aluminum, stainless steel, and brass. Regardless of the material selected, it is preferable that the material of the bracket 22 be the same as that of the housing 14.

[0050] (Assembly and Adjustment Method of Fly-Eye Lens 10)

[0051] Next, a method of assembling the above-mentioned fly-eye lens 10 will be briefly described, and then a method of adjusting the illumination of the exposure area using the fly-eye lens 10 will be described.

[0052] The prepared lens segments 20 are placed at both ends (holding portions 26) in the upper and lower holding grooves 42, and the lens segments 20 are arranged in the first direction. When all lens segments 20 are arranged, the first pressing member 46 and the second pressing member 48 accurately position each lens segment 20 relative to the reference position (the lower left corner in this embodiment).

[0053] Then, by attaching the pair of clamping plates 44 to the upper lateral holding frame 32 and the lower lateral holding frame 34, respectively, the lens unit 12 is completed. The two lens units 12 are then assembled to the housing 14, completing the fly-eye lens 10. When assembling the two lens units 12, it is preferable to set the reference positions of the lens units 12 so that they are substantially coaxial with respect to the optical axis of the fly-eye lens 10.

[0054] Adjusting the illumination distribution in the fly-eye lens 10's exposure area is accomplished by flipping several (at least one) of the multiple lens segments 20 that comprise the lens unit 12. Specifically, when arranging the multiple lens segments 20, the fly-eye lens 10's surface is positioned relative to the lens segments 20, either on its front or rear surfaces. As a result, in the adjusted fly-eye lens 10, a portion is formed by the front surfaces of the lens segments 20, while the remainder is formed by the rear surfaces.

[0055] Adjustment of the illumination distribution in the exposure area will be described in more detail. Generally, when the convex surface (the surface in this embodiment) of the lens 24 is arranged to face the outside, the outer shape of the irradiation range of the irradiation surface becomes a "pillow shape" (see Figure 5 ), when the convex surface is arranged to be inside (that is, when the back surface is arranged to be outside in this embodiment), the outer shape of the irradiation range of the irradiation surface becomes a "barrel shape" (refer to Figure 6 ). Moreover, in the "pincushion shape", the illumination at the four corners of the illumination range is relatively low, whereas in the "barrel shape", the illumination at the four corners of the illumination range is relatively high.

[0056] By utilizing such characteristics, the outer shape and illumination distribution of the irradiation range can be changed by inverting a portion of the lens segment 20 constituting each lens unit 12 .

[0057] Of course, it is also possible to adjust which of the front and back faces outward for each lens segment 20 or to collectively adjust the orientation of multiple lens segments 20. Furthermore, it is also possible to adjust which surface faces outward for each lens unit 12.

[0058] Furthermore, the degree to which the adjustment affects the illumination state varies depending on where the adjusted lens segment 20 is located within the lens unit 12. Generally, the illumination distribution of light emitted from a lamp in a light irradiation device relative to the fly-eye lens 10 is highest near the center of the fly-eye lens 10 and decreases concentrically from that center. Therefore, when adjusting the lens segment 20 located near the center of the lens unit 12, the illumination distribution on the illuminated surface also changes significantly.

[0059] Furthermore, by changing the interval between the pair of lens units 12 , it is also possible to adjust the illumination distribution.

[0060] (Characteristics of the Fly-Eye Lens 10)

[0061] According to the fly-eye lens 10 of this embodiment, by using lens segments 20 having front and back surfaces with different optical characteristics, the illumination of the exposure area can be adjusted by using the front or back surface of each lens segment 20 on the surface of the fly-eye lens 10. Therefore, according to the fly-eye lens 10 of the present invention, it is easy to adjust the illumination uniformly across a wide exposure area.

[0062] In addition, the compound eye lens 10 involved in this embodiment uses the lens unit 12 in a group of two pieces, and it is necessary to align the center axes of the lenses 24 of the relative group and the center axes of the lenses 24 of the other groups in parallel. However, since the configuration position can be adjusted in units of the lens segments 20 in one lens unit 12, these center axes can also be easily adjusted.

[0063] Moreover, as described above, as the glass or liquid crystal panel serving as the substrate becomes larger, the fly-eye lens also becomes larger, so the weight and size of the fly-eye lens itself become larger, making it difficult to operate. However, if it is the fly-eye lens 10 involved in this embodiment, it is assembled in units of lens segments 20, so it is easy to set it on the bracket 22.

[0064] Furthermore, in the case of a single lens unit 12 as in the conventional art, if any one of the lens units 12 has a defect, the entire lens unit 12 becomes useless. However, in the case of the fly-eye lens 10 according to this embodiment, only the lens segment 20 including the defective lens 24 needs to be replaced, thereby improving the yield of the lens unit 12 (fly-eye lens 10).

[0065] (Variant 1)

[0066] In the above-mentioned embodiment, each lens segment 20 is formed by arranging a plurality of lenses 24 in a second direction (the up-down direction in the figure), and aligning the plurality of lens segments 20 in a first direction (the left-right direction in the figure) to form a lens unit 12. However, the first direction and the second direction may be opposite, and the lens segment 20 may be formed by arranging a plurality of lenses 24 in the second direction (the left-right direction), and the lens unit 12 may be formed by aligning the plurality of lens segments 20 in the first direction (the up-down direction).

[0067] (Variant 2)

[0068] The structure of the bracket 22 is not limited to the above structure. For example, Figure 7As shown, the pair of vertical holding frames 30 , the upper lateral holding frame 32 , and the lower lateral holding frame 34 may be formed separately and assembled to form the quadrilateral bracket 22 .

[0069] The vertical retaining frame 30 is a component that is positioned on the left and right sides of the vertical axis when the bracket 22 is assembled. It has retaining frame retaining portions 36 formed at both ends, each having the same thickness as the retaining portion 26 of the lens segment 20. Furthermore, the thickness of the main body portion other than the retaining frame retaining portions 36 is formed to be slightly thicker than the maximum thickness of the lens 24 that constitutes the lens segment 20.

[0070] The upper horizontal retaining frame 32 is positioned laterally above the bracket 22 when the bracket 22 is assembled. A longitudinally extending upper groove 38 is formed on its lower surface. The retaining portion 26 of the lens segment 20 and the retaining frame retaining portion 36 of the vertical retaining frame 30 fit into this upper groove 38 .

[0071] The lower horizontal retaining frame 34 is positioned laterally below the bracket 22 when assembled. A longitudinally extending lower groove 40 is formed on its upper surface. The retaining portion 26 of the lens segment 20 and the retaining frame retaining portion 36 of the vertical retaining frame 30 fit into this lower groove 40 .

[0072] When assembling the fly-eye lens 10 using the holder 22 according to this second modification, after arranging the plurality of prepared lens segments 20 in a first direction, the vertical retaining frames 30 of the holder 22 are arranged at the left and right ends. This aligns the retaining portions 26 of each lens segment 20 and the retaining frame retaining portions 36 of the pair of vertical retaining frames 30 in a state aligned in one direction.

[0073] Then, the upper lateral holding frame 32 is attached so that the holding portion 26 and the holding frame holding portion 36 are fitted into the upper groove 38 of the upper lateral holding frame 32. Similarly, the lower lateral holding frame 34 is attached from the bottom.

[0074] The lens unit 12 is now completed. The completed pair of lens units 12 is housed in the housing 14, thereby completing the fly-eye lens 10.

[0075] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0076] Explanation of symbols

[0077] 10...Fly-eye lens, 12...Lens unit, 14...Casing

[0078] 20... lens segment, 22... bracket

[0079] 24 ... lens, 26 ... holding portion

[0080] 30 ...vertical holding frame, 32 ...upper lateral holding frame, 34 ...lower lateral holding frame, 36 ...holding frame holding portion, 38 ...upper groove, 40 ...lower groove, 42 ...holding groove, 44 ...clamping plate, 46 ...first pressing member, 48 ...second pressing member.

Claims

1. A fly-eye lens, comprising a plurality of lens segments arranged in a first direction. Each of the lens segments is formed by arranging a plurality of lenses in a second direction orthogonal to the first direction. The front and back surfaces of the lens segments have different optical properties from each other. The fly-eye lens adjusts the degree of light focusing of the fly-eye lens by selecting which of the surface and the back surface of the lens segment is configured on one surface of the fly-eye lens when arranging multiple lens segments, so that a part of the one surface of the fly-eye lens is composed of the surface of the lens segment and the remaining part of the one surface of the fly-eye lens is composed of the back surface of the lens segment. 2 . A light irradiation device comprising the fly-eye lens according to claim 1 .

3. A method for manufacturing a fly-eye lens, comprising preparing a plurality of lens segments each composed of a plurality of lenses arranged in a second direction orthogonal to a first direction, wherein the lens segments have mutually different optical properties on their front and back surfaces, and arranging the plurality of lens segments in the first direction to manufacture the fly-eye lens. In the manufacturing method of the fly-eye lens, when arranging a plurality of lens segments, it is selected whether the surface of the lens segment or the back surface is to be configured on one surface of the fly-eye lens, so that a portion of the one surface of the fly-eye lens is composed of the surface of the lens segment, and the remaining portion of the one surface of the fly-eye lens is composed of the back surface of the lens segment, thereby adjusting the focusing degree of the fly-eye lens.

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