Light source device

Abstract

To provide a light source device which achieves radiation illuminance distribution that does not have rapid changes in an incident surface of a fly eye lens.SOLUTION: A light source device includes a plurality of light-emitting elements, a collimation optical system which includes a plurality of lens regions arranged so as to correspond to each of the plurality of light-emitting elements at the rear stage of the plurality of light-emitting elements, and collimates light from a front focus of the lens regions, a condensing optical system for condensing the light emitted from the collimation optical system, and a fly eye lens on which the light emitted from the condensing optical system is incident, wherein when a focal distance of the condensing optical system is represented by f, a width which is perpendicular to the optical axis and becomes a maximum width of the collimation optical system is represented by b, and an axis coinciding with a line segment constituting the width b is represented by B, on a projection image of a light-emission surface on a back focus surface of the condensing optical system, a width of a projection image on an axis optically equivalent to the axis B is represented by a, and a clearance between an incident surface of the fly eye lens and a back focus of the condensing optical system is represented by L, a predetermined expression is satisfied.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a light source device, and more particularly to a light source device including a plurality of light emitting elements. [Background technology]

[0002] Conventionally, a light source device has been proposed that collimates light from a plurality of light-emitting elements arranged in an array, and then forms an image on the light entrance surface of a fly's eye integrator using a focusing optical system (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6651124 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 can be used, for example, as a light source for an exposure device. However, with the structure described in Patent Document 1, the light-emitting surfaces of the LEDs are projected onto the incident surface of the fly's eye integrator with almost no misalignment, resulting in an image that overlaps the light-emitting surfaces of the LEDs. If the LED light-emitting surfaces have a non-uniform in-plane distribution, the irradiance distribution will also be non-uniform on the incident surface of the fly's eye integrator. As a result, there is a high possibility that the irradiance distribution will also be non-uniform on the irradiation surface after passing through the fly's eye integrator.

[0005] In this patent, the amount of light incident on a unit area will be referred to as "irradiance" or "illuminance," and the amount of light emitted from a unit area and unit solid divergence angle will be referred to as "radiance" or "luminance."

[0006] Usually, when multiple light-emitting elements are arranged as light sources, the light-emitting elements have the same dimensions and shape. For example, when multiple light-emitting elements with wiring patterns formed on their light-emitting surfaces are arranged as light sources, the wiring patterns are the same. Furthermore, in such cases, the wiring patterns formed on the light-emitting surfaces of the light-emitting elements are often arranged so that they face the same direction when viewed toward the light-emitting surface.

[0007] In a light source device employing this configuration, the wiring pattern on the light-emitting surface of each light-emitting element becomes a non-light-emitting area, resulting in an uneven in-plane distribution of the LED light-emitting surface. Using multiple light-emitting elements configured with the same wiring pattern, the light emitted from each light-emitting element is projected via the first and second optical systems onto the incident surface of a fly's eye integrator located at the back focus of the second optical system. A sudden change in irradiance appears between the overlapping areas of the light-emitting and non-light-emitting areas on the projection surface.

[0008] A fly-eye integrator is composed of a fly-eye lens with multiple lenses arranged perpendicular to the optical axis, and an illumination lens with a front focus on the exit side of the fly-eye lens. At the back focus position (illumination surface) of the illumination lens, the individual lens surfaces on the entrance side of the fly-eye lens are projected in overlapping alignment without misalignment.

[0009] When light is incident on a fly's eye lens, if the incident light distribution within each lens surface on the incident side is randomly different, they will overlap on the irradiation surface, and a uniform irradiance distribution can be expected. However, if the incident light distribution within each lens surface on the incident side is patterned, even if they are overlapped, there is a high probability that the irradiance distribution on the irradiation surface will be non-uniform.

[0010] Here, the formation of partial non-light-emitting regions on the incident surface of the fly-eye lens has been explained based on the presence of a wiring pattern. However, it is believed that the same problem can arise even when a wiring pattern is not formed on the light-emitting surface and multiple light-emitting elements are mounted in which there is simply patterned variation in radiance on the light-emitting surface of the light-emitting element.

[0011] SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a light source device in which there is no sudden change in irradiance at the entrance surface of the fly-eye lens. [Means for solving the problem]

[0012] The light source device of the present invention comprises: A plurality of light-emitting elements; a collimating optical system including a plurality of lens regions disposed in a downstream stage of the plurality of light-emitting elements corresponding to the plurality of light-emitting elements, the lens regions respectively collimating light from front focuses of the lens regions; a focusing optical system that focuses the light emitted from the collimating optical system; a fly-eye lens onto which the light emitted from the condensing optical system is incident, The optical system is characterized in that the following formula (1) is satisfied: f is the focal length of the focusing optical system; b is the width that is perpendicular to the optical axis and is the maximum width of the collimating optical system; axis B is the axis that coincides with the line segment that constitutes width b; a is the width of the projected image of the light-emitting surface on the back focus plane of the focusing optical system, on an axis that is optically equivalent to axis B; and L is the distance between the incident surface of the fly-eye lens and the back focus of the focusing optical system.

[0013]

number

[0014] The width a of the projected image plane is the width of the projected image on an axis that is optically equivalent to axis B, which coincides with the line segment that constitutes width b, the maximum width of the collimating optical system, when a screen is placed at the back focus of the focusing optical system. Here, the "axis that coincides with the line segment that constitutes width b" is defined as axis B. Specifically, the "axis that is optically equivalent to axis B" refers to an axis that is perpendicular to the optical axis and extends in the same direction as axis B (axis A or axis C in FIG. 1A), as shown in FIG. 1A (described later), or an axis that is perpendicular to the optical axis and extends in the axial direction that is a mirror image of axis B at mirror M (axis A or axis C in FIG. 1B), as shown in FIG. 1B. The "optical axis" in this application refers to axis LA, which passes through the center point Ip of the illumination surface of the light source device. When distinguishing between positive and negative optical axis directions, the direction of radiation from the light source is referred to as the +LA direction, and the opposite direction is referred to as the -LA direction.

[0015] According to the above configuration, the images of the light-emitting surfaces of the plurality of light-emitting elements are projected in a state of being shifted from one another, which prevents areas of high irradiance and areas of low irradiance in the images of the light-emitting elements from overlapping on the incident surface of the fly-eye lens, thereby suppressing abrupt changes in irradiance.

[0016] In other words, with the above configuration, compared to a light source device with a conventional configuration in which the images of the light-emitting surfaces of multiple light-emitting elements are formed on the incident surface of the fly-eye lens in an overlapping manner without any shift, sudden changes in irradiance are suppressed and the irradiance distribution is made uniform on the irradiation surface.

[0017] The light source device is When the minimum width of the entrance surface of the fly-eye lens is D, the width D may be configured to satisfy the following formula (2).

[0018]

number

[0019] With this configuration, substantially all of the effective components of the light beams collimated by the collimating optical system are incident on the incident surface of the fly's eye lens, which means that the light emitted from each light-emitting element can be more efficiently taken into the incident surface of the fly's eye lens.

[0020] A fly's eye lens is an optical member in which a plurality of lens elements are arranged in a matrix, and each lens element typically has a circular, rectangular, or hexagonal shape. The contour may be square, circular or hexagonal, but need not correspond to the shape of the lens element. [Effects of the Invention]

[0021] According to the present invention, a light source device is realized in which abrupt changes in irradiance are suppressed on the incident surface of the fly-eye lens, resulting in a more uniform irradiance distribution on the irradiation surface. [Brief explanation of the drawings]

[0022] [Figure 1A] 1 is a diagram schematically illustrating a configuration of an embodiment of a light source device. [Figure 1B] 10 is a diagram schematically illustrating a modified example of the light source device according to the embodiment. [Figure 2] 1 is a diagram schematically illustrating the structure of a collimating optical system when viewed in the optical axis direction (−LA direction) from the light collecting optical system side. [Figure 3A] 1 is a diagram schematically illustrating a state in which light emitted from an end of a collimating lens, excluding a fly-eye lens, is imaged at the back focus of a focusing optical system. [Figure 3B] 3B is a diagram schematically illustrating an example of a correspondence relationship between an image formed at the back focus of a focusing optical system and the collimating optical system in the optical system of FIG. 3A. [Figure 3C] 3C is an alternative configuration of the optical system of FIG. 3B. [Figure 4A]1 is a diagram schematically illustrating a state in which light emitted from an arbitrary point of each lens element of a collimating optical system is projected onto the entrance surface of a fly's eye lens. [Figure 4B] 4B is a diagram schematically illustrating an example of a correspondence relationship between an image projected onto an entrance surface of a fly's eye integrator optical system by the optical system of FIG. 4A and the collimator optical system. [Figure 5] 1 is a schematic diagram for explaining the arrangement relationship of an optical system. [Figure 6] 1 is a diagram schematically illustrating an example of a correspondence relationship between an image projected onto an entrance surface of a fly's eye lens and the outline of the entrance surface of the fly's eye lens. DETAILED DESCRIPTION OF THE INVENTION

[0023] The light source device of the present invention will be described below with reference to the drawings. Note that the drawings are all schematic illustrations, and the numbers on the drawings do not necessarily correspond to the actual numbers.

[0024] FIG. 1A is a diagram schematically illustrating the configuration of one embodiment of a light source device 1. As shown in FIG. 1A, the light source device 1 includes a plurality of light-emitting elements (10, 10, . . .), a collimating optical system 11, a focusing optical system 12, and a fly-eye lens 13, which is a component of a fly-eye integrator. The fly-eye lens 13 is disposed at a position spaced apart from a back focus 12F of the focusing optical system 12. The front focus of each lens region (11a, 11a, . . .) included in the collimating optical system 11 substantially coincides with the center position of the light-emitting surface 10s of the corresponding light-emitting element (10, 10, . . .). Here, "substantially coincident" means that the distance between the front focus and each center position is close to, within 0.5 to 1.5 times the focal length of the lens region.

[0025] FIG. 1B is a diagram schematically showing the configuration of a modified example of light source device 1, following FIG. 1A.

[0026] 1A and 1B, axis B is the axis that is orthogonal to optical axis LA and coincides with the line segment that forms the maximum width b of collimating optical system 11, and axis A is the axis that is optically equivalent to axis B and passes through back focus 12F. For example, in FIG. 1A, axes B and A are each shown as parallel axes extending in the +X direction on the page. However, in an embodiment in which mirror M is disposed on optical axis LA as in FIG. 1B, axis B is an axis that extends in the +X direction on the page, while axes A and C are shown as axes that are mirror images of mirror M and extend in the −Z direction on the page. Note that the arrows in the X, Y, and Z directions shown on the page indicate that the direction indicated by the arrow is the + direction and the opposite direction is the − direction.

[0027] 2 is a diagram schematically illustrating the structure of the exit surface 11s of the collimating optical system 11 when viewed in the optical axis direction (-LA direction) from the side of the focusing optical system 12. The maximum width b of the collimating optical system is the length between the end 11s1p of the collimating optical system 11 at its widest point and another end 11s2p.

[0028] An axis passing through the end 11s1p of the collimating optical system 11 with the widest width and another end 11s2p shown in Fig. 2 is defined as axis B. Note that axis B does not extend in the same direction (e.g., the X direction) on the paper when viewed in the optical axis direction (-LA direction) at the exit surface 11s of the collimating optical system 11, the entrance surface 13s of the fly-eye lens 13, and the back focus plane 12Fs of the focusing optical system (see Fig. 3A described later), but extends in an optically equivalent direction.

[0029] FIG. 3A is a diagram showing a schematic diagram of the state in which the light emitted from each light-emitting element 10 is imaged on a back focus plane 12Fs of the light-collecting optical system, with the fly-eye lens 13 removed from FIG.

[0030] 3B is a diagram schematically illustrating a projected image Im0 of the light-emitting surface on the back focal plane 12Fs of the focusing optical system 12 by the optical system of FIG. 3A when viewed from the same direction as FIG. 2. The exit surface 11s of the collimating optical system 11 in FIG. 2 is shown by a dashed line, with the axis B coinciding with it. Note that the axis A, which is optically equivalent to the axis B, is also shown coinciding with the axis B.

[0031] The length between end 12Fsp1 and another end 12Fsp2 of the width of the projected image of the light-emitting surface on back focal plane 12Fs of focusing optical system 12, which is on axis B, is defined as width a of the projected image of the light-emitting surface on back focal plane 12Fs of focusing optical system 12. The outer edge of the projected image on back focal plane 12F here is considered to have a boundary at a value (half value) that is 50% of the peak intensity in the in-plane irradiance distribution of the projected image.

[0032] 3C is another example of FIG. 3B. As shown in FIG. 3C, when there are multiple axes (b0, b1, b2) along which the collimating optical system 11 has the maximum width, the axis with the shortest width among the widths (a0, a1, a2) of the projected image of the light-emitting surface on those axes is determined to be axis A. The end 11s1p of the collimating optical system 11 with the maximum width, another end 11s2p of the collimating optical system 11 with the maximum width, the end 12Fsp1 of the width of the projected image of the light-emitting surface, and another end 12Fsp2 of the width of the projected image of the light-emitting surface are all defined on axis B and axis A, which is optically equivalent to axis B.

[0033] 4A is a diagram schematically illustrating a state in which light emitted from each light-emitting element 10 passes through the collimating optical system 11 and the condensing optical system 12 and is incident on the incident surface 13s of the fly-eye lens 13. Each light emitted from an arbitrary point on the exit surface 11s of the collimating optical system 11 passes through the condensing optical system 12 and is projected onto the incident surface 13s of the fly-eye lens 13.

[0034] 4B is a diagram schematically illustrating an example of an image projected onto the incident surface 13s of the fly-eye lens 13. For convenience of illustration, five projected images Im1 to Im5 are shown in FIG. 4B as projected images of the light-emitting surface on the incident surface 13s of the fly-eye lens 13. However, in reality, the image is composed of countless projected images emitted from countless arbitrary points on the exit surface 11s of the collimating optical system 11. When these images are combined, they form a blurred image. As in FIG. 3B, the exit surface 11s of the collimating optical system 11 is indicated by a dashed line, with axis B coinciding with the optically equivalent axis C.

[0035] The length between end 13sp1 and another end 13sp2 of the width of the projected image of the light-emitting surface on incident surface 13s of fly-eye lens 13, which is on axis C that is optically equivalent to axis B, is defined as width c of the projected image of the light-emitting surface on incident surface 13s of fly-eye lens 13s. Here, the outer edges of projected images Im1 to Im5 of the light-emitting surface on incident surface 13s of fly-eye lens 13 are considered to have a boundary at a value that is 10% of the peak intensity in the in-plane distribution of the projected image.

[0036] Figure 5 is a schematic ray diagram for explaining the optical relationship of the light source device 1, and conceptually shows the light rays emitted from the widest end 11s1p and another end 11s2p of the collimating optical system 11.

[0037] The focal length f of the focusing optical system 12 is the distance to the back focus 12F where the light is focused when parallel light passes through the focusing optical system 12. Specifically, when a light ray parallel to the optical axis is incident on the focusing optical system 12 from the widest end 11s1p of the collimating optical system 11, the position where the light ray intersects with the central axis (optical axis) of the focusing optical system 12 is considered to be the back focus position, and is defined as the distance between the focusing optical system 12 and the back focus 12F.

[0038] The distance L is defined by the distance between the back focus 12F of the focusing optical system 12 and the entrance surface 13s of the fly-eye lens 13.

[0039] The separation distance L may be set either on the upstream side (-LA direction) or downstream side (+LA direction) of the optical axis LA with respect to the back focus 12F of the focusing optical system 12. More specifically, the entrance surface 13s of the fly-eye lens 13 may be disposed at a distance on the downstream side (+LA direction) of the optical axis LA when viewed from the back focus 12F.

[0040] The magnification of the width c of the projected image of the light emitting surface on the incident surface 13s of the fly-eye lens 13 relative to the width a of the projected image of the light emitting surface on the back focus surface 12Fs of the light collecting optical system 12 is referred to as a predetermined magnification γ.

[0041] 6 is a diagram schematically showing an example of the correspondence between the outline 13e of the fly-eye lens 13 and the projected images Im1 to Im5 of the light-emitting surface on the incident surface 13s of the fly-eye lens 13. The minimum width of the incident surface 13s of the fly-eye lens 13 is taken as width D of the fly-eye lens 13. As in FIG. 3B, the exit surface 11s of the collimating optical system 11 is shown by a dashed line with the axis B and axis C coinciding.

[0042] The positional relationship of each element included in the light source device 1 will be described below.

[0043] 3A, images of the light-emitting surfaces 10s of the light-emitting elements (10, 10, ...) are overlapped without any shift and projected onto the back focus plane 12Fs of the focusing optical system 12. As a result, the light-emitting regions of the light-emitting surfaces 10s overlap without any shift and the non-light-emitting regions of the light-emitting surfaces 10s overlap without any shift, so that the image projected onto the back focus 12F of the focusing optical system 12 becomes a projected image Im0, which is an almost direct projection of the light-emitting surfaces 10s of the light-emitting elements, in which the light-emitting regions Ima and non-light-emitting regions Imb are relatively easily visible, as shown in FIG.

[0044] However, when an image in which the light-emitting region Ima and the non-light-emitting region Imb are clearly visible is incident on the incident surface 13s of the fly-eye lens 13, as described above, there is a high probability that the irradiance distribution will become non-uniform on the irradiation surface after passing through the fly-eye integrator optical system.

[0045] In contrast, when the back focus 12F of the focusing optical system 12 and the incident surface 13s of the fly-eye lens 13 do not coincide with each other but are arranged at a distance L apart as shown in FIG. 1, overlapping of areas of high irradiance and areas of low irradiance in the projected images of the light-emitting elements (10, 10, ...) is suppressed, and sudden changes in irradiance are suppressed.

[0046] 4A, light emitted from light-emitting surface 10s of each light-emitting element (10, 10, ...) is collimated by collimating optical system 11 and projected onto incident surface 13s of fly-eye lens 13 at a position away from back focus 12F of focusing optical system 12. At this time, the image reflected on incident surface 13s of fly-eye lens 13 in light source device 1 becomes a blurred image made up of countless projected images Im1 to Im5 of the light-emitting surface on incident surface 13s of fly-eye lens 13, as shown in FIG. 4B, because incident surface 13s of fly-eye lens 13 is positioned at a position different from back focus 12F of focusing optical system 12.

[0047] The blurred images suppress the overlap between the light-emitting regions Ima of each image and the overlap between the non-light-emitting regions Imb of each image, and an irradiance distribution without sudden changes is incident on the entrance surface 13s of the fly-eye lens 13.

[0048] However, if the countless projected images Im1 to Im5 are shifted only slightly, the irradiance distribution of the projected images incident on the entrance surface 13s of the fly-eye lens 13 does not sufficiently suppress abrupt changes.

[0049] Here, the inventors have conducted extensive research and established conditions for sufficiently suppressing abrupt changes in the irradiance distribution of the projected image incident on the entrance surface 13 s of the fly-eye lens 13 .

[0050] It was found that this condition satisfies the area where the width c of the projected image of the light-emitting surface on the incident surface 13s of the fly-eye lens 13 is at least 1.1 times larger than the width a of the projected image of the light-emitting surface on the incident surface 13s of the fly-eye lens 13, thereby sufficiently suppressing sudden changes in the irradiance distribution of the projected image incident on the incident surface 13s of the fly-eye lens 13.

[0051] Under these conditions, the light emitting area Ima and the non-light emitting area Imb of the light emitting surface do not form a relatively visible projected image, and a more uniform projected image is likely to be formed.

[0052] Conversely, if the width c of the projected image of the light-emitting surface on the incident surface 13s of the fly-eye lens 13 expands to an area at least twice the width a of the projected image of the light-emitting surface at the back focus 12F of the focusing optical system 12, the overlap of the projected images Im1 to 5 of the light-emitting surface on the incident surface 13s of the fly-eye lens 13 will be reduced, and the overlapping area of ​​the farthest images Im1 and Im2 will disappear.

[0053] From the above, the width c is a predetermined magnification γ times the width a. The preferable magnification range is as follows: 1.1<γ<2.0

[0054] It can be said that the width c of the projected image of the light emitting surface on the incident surface 13s of the fly-eye lens 13 is preferably within the range of the following equation (3) obtained by multiplying the above equation by the width a and substituting aγ=c. 1.1a <c<2.0a (3)

[0055] Since the ratio of the separation distance L, the length (γa-a) obtained by subtracting the width a from the width γa to the maximum width b of the collimating optical system 11, and the ratio of the absolute value of the separation distance L to the focal length f of the focusing optical system 12 are equal, the relationship in equation (4) below can be derived. (γ-1)a : b = |L| : f (4)

[0056] From the above formula (4), the following formula (5) is obtained. γ = (b |L|) / (a f) + 1 (5)

[0057] Furthermore, the following equation (6) is obtained from the above equations (3) and (5). 1.1 < (b ·|L|) / (a · f) + 1 < 2.0 (6)

[0058] Then, by transforming the above formula (6), the above formula (1) is obtained. Just to be sure, the above formula (1) is shown again.

[0059]

number

[0060] By transforming the above formula (1), the following formula (7) is obtained. 0.1af / b < |L| < 1.0af / b (7)

[0061] That is, by setting the separation distance L within the range of the above formula (7), the width c of the projected image of the light emitting surface on the incident surface 13s of the fly-eye lens 13 is designed to satisfy the above formula (1).

[0062] Furthermore, in the above formulas (3) and (6), the range of the magnification γ is set to be greater than 1.1 and less than 2. However, if the range of the width c(γa) becomes too large, the degree of overlap of the images will become small, and the irradiance at the incident surface will likely become small. Therefore, it is more desirable to set the magnification γ in a range less than 1.5. Therefore, it is more desirable to set the separation distance L within the range of the following formula (8). 0.1af / b < |L| < 0.5af / b (8)

[0063] Furthermore, in the above formula (8), from the viewpoint of ensuring a more stable and uniform irradiance distribution of the projected image, it is more preferable to set the range of the magnification γ to be greater than 1.2 and less than 1.5. Therefore, it is more preferable to set the separation distance L within the range of the following formula (9). 0.2af / b < |L| < 0.5af / b (9)

[0064] 6, if the minimum width D of the fly-eye lens 13 is larger than at least the overall width c of the projected image, substantially all of the effective components of the light beam collimated by the collimating optical system 11 will be incident on the entrance surface 13s of the fly-eye lens 13. Therefore, from the viewpoint of light utilization efficiency, it is preferable to satisfy the relationship D>c.

[0065] Then, the above equation (2) is obtained from the relationship D>c and the above equation (5). Just to be sure, the above equation (2) is shown again.

[0066]

number

[0067] Note that, just as an example, in this embodiment, the width b is set to 90 mm, and the width a is designed to be 60 mm using a focusing optical system 12 with a focal length f of 400 mm. By setting the separation distance L within the range of 26.7 mm to 133 mm, the image projected onto the entrance surface 13s of the fly-eye lens 13 is adjusted to have an irradiance distribution that does not change suddenly.

[0068] In other words, with the above configuration, compared to a light source device with a conventional configuration in which the projected images Im1 to Im5 of the light-emitting surface on the incident surface 13s of the fly-eye lens 13 are formed at approximately the same position, the projected images are sufficiently dispersed, and an irradiance distribution without sudden changes is realized.

[0069] The configuration of the light source device 1 described above is merely an example, and the present invention is not limited to the illustrated configurations. [Explanation of symbols]

[0070] 1 : Light source device 10: Light-emitting element 10s: Light-emitting surface 11: Collimated optical system 11a: Lens element of collimating optical system 11s: Exit surface of collimating optical system 11s1p: Widest end of collimating optical system 11s2p: The other end of the maximum width of the collimating optical system b: Maximum width of the collimating optical system b0~2: Maximum width of the collimating optical system 12: Condensing optical system 12F: Back focus of the focusing optical system 12Fs: Back focal plane of the focusing optical system Ima: Light-emitting area of ​​the light-emitting surface Imb: Non-luminous area of ​​the luminous surface Im0: Projected image of the light-emitting surface on the back focus plane of the focusing optical system 12Fsp1: Width edge of the projected image of the light-emitting surface 12Fsp2: Another end of the width of the projected image of the light-emitting surface a: Width of the projected image of the light-emitting surface on the back focus plane of the focusing optical system a0~2: Width of the projected image of the light-emitting surface on the back focus plane of the focusing optical system 13: Fly-eye lens 13a: Fly-eye lens element 13s: Fly-eye lens entrance surface Im1-5: Projected image of the light-emitting surface on the incident surface of the fly-eye lens 13sp1: Width edge of the projected image of the light-emitting surface 13sp2: Another end of the width of the projected image of the light-emitting surface 13e: Outline of the fly-eye lens 20: PCB c: Width of the projected image of the light-emitting surface on the incident surface of the fly-eye lens L: Separation distance f: focal length of the focusing optical system γ: Predetermined magnification D: Minimum width of the fly-eye lens LA: Optical axis A: A axis B: B axis C: C-axis Ip: Center point of the irradiation surface M: Mirror 30: Irradiation lens 31s: Irradiation surface

Claims

1. A plurality of light-emitting elements; a collimating optical system including a plurality of lens regions disposed in a downstream stage of the plurality of light-emitting elements corresponding to the plurality of light-emitting elements, the lens regions respectively collimating light from front focuses of the lens regions; a focusing optical system that focuses the light emitted from the collimating optical system; a fly-eye lens onto which the light emitted from the condensing optical system is incident, a light source device characterized in that the following formula (1) is satisfied, where f is the focal length of the focusing optical system, b is the width that is perpendicular to the optical axis and is the maximum width of the collimating optical system, axis B is the axis that coincides with the line segment that constitutes width b, a is the width of the projected image of the light-emitting surface on an axis that is optically equivalent to axis B in a projected image of the light-emitting surface on a back focus plane of the focusing optical system, and L is the distance between the incident surface of the fly-eye lens and the back focus of the focusing optical system. [Equation 1]

2. 2. The light source device according to claim 1, wherein when the minimum width of the entrance surface of the fly-eye lens is D, the width D satisfies the following formula (2): [Equation 2]

Images