Light source device

Abstract

To provide a light source device that includes a plurality of LEDs, and is capable of irradiating an irradiation surface larger than conventional ones with light.SOLUTION: A light source device severally comprises: a plurality of LEDs; a first collimating optical system including a plurality of first lens regions which is arranged corresponding to each of the plurality of LEDs on a rear stage of the plurality of LEDs; a plurality of light source unit including a first condensing optical system which condenses emitted light from the first collimating optical system; a second collimating optical system including a plurality of second lens regions which is arranged corresponding to each of the plurality of light source units on a rear stage of the plurality of light source units; and a second condensing optical system which condenses emitted light from the second collimating optical system. The plurality of light source units form a discrete secondary light source on a back focus position of the first condensing optical system. The positions of front focuses of the plurality of lens regions substantially match the positions of back focuses of the corresponding first condensing optical system.SELECTED DRAWING: Figure 1

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 LEDs.

Background Art

[0002] Conventionally, the inventor has proposed a light source device that collimates light from a plurality of LEDs arranged in an array and then forms an image on the light incident surface of a fly-eye integrator using a condenser optical system (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems 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 apparatus. Here, when the area of the region to be exposed increases, it becomes necessary to increase the number of installed LEDs and the installation area on the light source side accordingly. However, under the structure described in Patent Document 1, there is a limit to increasing the number of installed LEDs.

[0005] Specifically, due to factors such as an increase in the supplied current amount and a temperature rise, there is a limit to the number of LEDs that can be mounted on a single substrate. For example, assuming that a light source in which 100 LEDs are mounted on a 100 mm square AlN substrate has been used conventionally, to quadruple the number of LEDs, theoretically, 400 LEDs should be mounted on a 200 mm square AlN substrate. However, at present, a 200 mm square AlN substrate does not exist.

[0006] Furthermore, there are also problems with mechanical accuracy associated with the increase in component size. For example, when an accuracy of ±1 mm is required, for a 100 mm square AlN substrate, it can be manufactured with an accuracy of ±1%. However, for a 200 mm square AlN substrate, an accuracy of ±0.5% is required. When collimating the light from a plurality of LEDs with a collimating optical system and then guiding it to a condensing optical system as in the structure of Patent Document 1, precise position adjustment of each optical system is necessary. Therefore, the reduction in the allowable range of design errors associated with the increase in component size makes it difficult to obtain the desired light with the light source device.

[0007] Furthermore, increasing the number of LEDs mounted on the same substrate will lead to an increase in the current amount and temperature rise, which may cause thermal expansion of the substrate, the holding part of the optical system, etc. The substrate and the holding part of the optical system are made of different materials. The substrate is typically made of ceramic, and the holding part is made of metal. As a result, when both the substrate and the holding part are heated, a displacement occurs between them due to the difference in thermal expansion, and distortion occurs in the optical arrangement of the LED and the optical system.

[0008] Due to the above circumstances, at present, in order to increase the number of LEDs compared to the conventional level, it is necessary to arrange a plurality of substrates on which a plurality of LEDs are mounted.

[0009] Here, in the structure described in Patent Document 1, the light emitted from a plurality of LEDs is collimated and then condensed by a condensing optical system. Here, it is practically difficult to arrange a plurality of LEDs mounted on the same substrate without gaps due to the arrangement of wiring etc., and gaps are inevitably generated between the plurality of LEDs. When arranging a plurality of substrates with the structure described in Patent Document 1 side by side to increase the area, it is difficult to make the intervals between a plurality of LEDs mounted within the same substrate and the intervals between the LEDs mounted on each adjacent substrate exactly the same. Therefore, in the structure of Patent Document 1, for the light emitted from the condensing optical system, an interval is also generated between the light fluxes from the LEDs mounted on different substrates, resulting in a decrease in the average luminance.

[0010] In view of the above problems, an object of the present invention is to provide a light source device including a plurality of LEDs and capable of irradiating light onto an irradiation surface larger than the conventional one.

Means for Solving the Problems

[0011] The light source device according to the present invention includes a plurality of light source units, each of which includes a plurality of LEDs and a plurality of first lens regions arranged corresponding to each of the plurality of LEDs at the subsequent stage of the plurality of LEDs, and a first collimating optical system that collimates light from the front focus of the first lens region, and a first condensing optical system that condenses the light emitted from the first collimating optical system. At the subsequent stage of the plurality of light source units, it includes a plurality of second lens regions arranged corresponding to each of the plurality of light source units, and a second collimating optical system that collimates light from the front focus of the second lens region. And a second condensing optical system that condenses the light emitted from the second collimating optical system. The plurality of light source units form discrete secondary light sources at the back focus positions of the first condensing optical systems included in each of the plurality of light source units. The positions of the front foci of each of the plurality of second lens regions included in the second collimating optical system substantially coincide with the positions of the back foci of the first condensing optical systems included in the corresponding plurality of light source units.

[0012] According to the above configuration, a plurality of light source units form secondary light sources at the back focus positions of their respective first condensing optical systems. These secondary light sources are formed at discrete positions from each other. The light emitted from each secondary light source is expanded and then its divergence angle is reduced by the second lens region of the second collimating optical system, and then guided to the second condensing optical system. Also, for all the light emitted from the secondary light sources, by passing through the second collimating optical system, the divergence angle of the total luminous flux is reduced and it is guided to the second condensing optical system. When the secondary light sources substantially coincide with the front focus positions of the second lens region provided in the second collimating optical system, the light beam emitted from the secondary light sources becomes substantially parallel light as a whole and is guided to the second condensing optical system.

[0013] That is, according to the above configuration, the light emitted from a plurality of LEDs mounted on a single light source unit can be utilized as the light from the secondary light sources formed at the back focus positions of the first condensing optical system.

[0014] As a result, the light emitted from different light source units can be utilized as a plurality of secondary light sources formed discretely at different positions. And by collimating and then condensing the light from each of these secondary light sources, it becomes difficult for gaps to occur between the light beams from each secondary light source.

[0015] In addition, when a plurality of LEDs are arranged at the front focus positions of the first lens regions corresponding to the respective LEDs, the size of the secondary light sources becomes smaller and the luminance is increased. However, the LEDs do not necessarily have to be arranged at the front focus positions of the first lens regions, and they may be arranged at positions deviated from the front focus by a distance of 50% or less of the focal length of the first lens region in the optical axis direction.

[0016] In this specification, when a certain position Z1 is displaced from the focus position Z2 of an optical system by a distance within 10% of the focal length of the same optical system, it is considered that the position Z1 substantially coincides with the focus position Z2 of the optical system.

[0017] When viewed from the side where light is emitted from the second collimating optical system, the plurality of second lens regions may be arranged adjacent to each other via a linear boundary.

[0018] According to the above configuration, a plurality of second lens regions for collimating light from each secondary light source are arranged closely. As a result, the respective light beams emitted from the second collimating optical system including the plurality of second lens regions are also closer to each other.

[0019] The light source device may further include an integrator optical system into which the light emitted from the second condensing optical system is incident, and the light incident surface of the integrator optical system may be arranged at a position substantially coinciding with the back focus of the second condensing optical system. The integrator optical system may be a fly-eye integrator or a rod integrator.

[0020] A fly-eye integrator is an optical member in which a plurality of lens elements are arranged in a matrix, and the plurality of lens elements are arranged on each of the incident side and the emission side. The lens elements on the incident side have a focus at the position of the lens elements on the emission side, and the lens elements on the emission side have a focus at the position of the lens elements on the incident side. Each lens element typically has a circular, square, rectangular, or regular hexagonal shape. A rod integrator is an optical member that guides the light incident from the incident surface to the emission surface while repeating reflection on the inner surface, and is composed of, for example, a columnar member made of a light-transmissive material such as glass or resin, a hollow member whose inner surface is composed of a reflecting mirror, and the like.

[0021] When a projection surface is arranged on the light emission surface side of the second collimating optical system, the shape of the image projected on the projection surface may correspond to the shape of the lens elements of the fly-eye integrator.

[0022] According to this configuration, since the incident angle of the fly-eye integrator and the incident angle from the second light condensing optical system can be substantially matched, it is possible to guide the light from the secondary light source to the fly-eye integrator without excess or deficiency. Here, the shape of the image projected on the projection surface can be controlled by adjusting the arrangement mode of the plurality of LEDs mounted on the light source unit and the first collimating optical system arranged corresponding to the plurality of LEDs.

[0023] For example, when the lens element of the fly-eye integrator is circular, the shape of the image projected on the projection surface may be substantially circular. The "substantially circular shape" as used herein means that when comparing the shape formed by connecting the outer edges of the image with the quadrilateral circumscribing the outer edge of the image, the former is smaller than the latter, and no image is formed in the vicinity of the four vertices of the latter quadrilateral. Examples of the shape of the lens element include a regular hexagon, a square, a rectangle, etc. in addition to a circle. The shape of the image projected on the projection surface may be substantially circular, regular hexagonal, square or rectangular corresponding to the shape of the lens element.

Advantages of the Invention

[0024] According to the present invention, even when an LED is used as the primary light source, a light source device capable of suppressing a decrease in average luminance for an irradiation surface larger than before is realized.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10A

Figure 10B

Figure 11A

Figure 11B

Figure 12A

Figure 12B

Figure 13A

Figure 13B

Embodiments for Carrying Out the Invention

[0026] Hereinafter, embodiments of the light source device according to the present invention will be described with reference to the drawings as appropriate. Note that the dimensional ratios in each figure do not necessarily match the actual dimensional ratios, and the dimensional ratios do not necessarily match between the drawings. Also, the number of components shown in each figure does not necessarily match the actual number of components. Furthermore, in each figure, for convenience of explanation, some elements may be exaggeratedly illustrated.

[0027] FIG. 1 is a drawing schematically showing the configuration of an embodiment of the light source device according to the present invention. FIGS. 2 and 3 are both partial enlarged views of FIG. 1. Hereinafter, the description will be made using the X - Y - Z coordinate system appropriately attached to FIG. 1.

[0028] As shown in FIG. 1, the light source device 1 includes a plurality of light source units 10, 10,.... FIG. 2 is an enlarged view of the light source unit 10. The light source unit 10 includes a plurality of LEDs 3, 3,... a first collimating optical system 5, and a first condensing optical system 7.

[0029] As shown in Fig. 2, the first collimating optical system 5 includes a plurality of first lens regions 5a, 5a,... arranged corresponding to the plurality of LEDs 3, 3,.... The first collimating optical system 5 collimates the light 5a that has reached the front focus of the first lens regions 5a, 5a,... and guides it to the subsequent stage. Typically, by arranging the plurality of LEDs 3, 3,... at the front focus positions of the first lens regions 5a, 5a,..., the first collimating optical system 5 collimates the light emitted from each of the plurality of LEDs 3, 3,... as a whole and guides it to the first condensing optical system 7. The first condensing optical system 7 condenses the light emitted from the first collimating optical system 5. More specifically, the first condensing optical system 7 condenses the plurality of lights emitted from the first collimating optical system 5 at the back focus 8 of the first condensing optical system 7. That is, at the position of the back focus 8 of the first condensing optical system 7, a secondary light source 15 is formed in the form of an image formed by the light from each LED 3, 3,....

[0030] Returning to Fig. 1 again to continue the explanation. Each of the plurality of light source units 10, 10,... includes the plurality of LEDs 3, 3,... described above with reference to Fig. 2, the first collimating optical system 5, and the first condensing optical system 7. As a result, as shown in Fig. 1, corresponding to each of the plurality of light source units 10, 10,..., secondary light sources 15, 15,... are formed at discrete positions.

[0031] In this embodiment, as an example, it is assumed that the light source device 1 includes four sets of light source units 10, 10,.... In Fig. 1, only two sets of light source units 10a and 10b are shown, but in the depth direction of the paper surface (+Y direction), two more sets of light source units 10c and 10d are provided (see Fig. 4 described later). More specifically, the light source unit 10c is arranged behind the light source unit 10a (+Y side), and the light source unit 10d is arranged behind the light source unit 10b (+Y side). In this case, discrete secondary light sources 15, 15,... are formed at four different positions by each light source unit 10, 10,....

[0032] As shown in FIG. 1, the light source device 1 includes a second collimating optical system 20 disposed downstream of the light source units 10, 10,.... FIG. 3 is an enlarged view of the vicinity of the second collimating optical system 20. As shown in FIG. 3, the second collimating optical system 20 includes a plurality of second lens regions 20a, 20b,... that collimate the light emitted from the light source units 10, 10,.... In other words, the light emitted from the secondary light sources 15, 15,....

[0033] As shown in FIG. 3, the position of the front focus 19a of the second lens region 20a included in the second collimating optical system 20 substantially coincides with the position of the back focus 8a of the first condensing optical system 7a included in the corresponding light source unit 10a. Similarly, the position of the front focus 19b of the second lens region 20b included in the second collimating optical system 20 substantially coincides with the position of the back focus 8b of the first condensing optical system 7b included in the corresponding light source unit 10b. Although not shown, the same applies to the positions of the front focus of the second lens region 20c and the front focus of the second lens region 20d.

[0034] More specifically, as shown in FIG. 3, the light emitted from the secondary light source 15a formed by the light source unit 10a is collimated by the second lens region 20a included in the second collimating optical system 20 and guided to the downstream stage. Similarly, the light emitted from the secondary light source 15b formed by the light source unit 10b is collimated by the second lens region 20b included in the second collimating optical system 20 and guided to the downstream stage. Although not shown in FIG. 3, the secondary light source 15c formed by the light source unit 10c and the secondary light source 15d formed by the light source unit 10d are similarly collimated by the corresponding second lens region and guided to the downstream stage.

[0035] FIG. 4 is a plan view schematically showing the arrangement of the first collimating optical system 5 and the first condensing optical system 7 provided in each light source unit 10, 10, ..., and corresponds to the drawing when viewed from the light emitting surface side of the first condensing optical system 7. In FIG. 4, the first condensing optical system 7 is marked with a reference numeral corresponding to the mounted light source unit 10. That is, the first condensing optical system 7a shown in FIG. 4 is mounted on the light source unit 10a, and the first condensing optical system 7b is mounted on the light source unit 10b. The same applies to the first condensing optical system 7c and the first condensing optical system 7d.

[0036] Although not shown in FIG. 4, LEDs 3 are arranged in the depth direction (-X direction) of the paper surface with respect to the first collimating optical system 5.

[0037] FIG. 5 is a drawing schematically showing an image projected when a projection surface is installed at the back focus position on the light emitting surface side of the second collimating optical system 20 in FIG. 3.

[0038] As described above with reference to FIG. 2, the light emitted from the light source unit 10 travels while reducing the divergence angle, is condensed at the position of the back focus 8 of the first condensing optical system 7, and forms a secondary light source 15 in a state where the light from each LED 3, 3, ... is imaged. Thereafter, the light travels from the secondary light source 15 while expanding the divergence angle again, and is guided to the second collimating optical system 20 as shown in FIG. 3.

[0039] Continuing the description by focusing on the light source unit 10a among the light source units 10a, 10b, ... shown in FIG. 4. In FIG. 4, for convenience of explanation, the light (light beam) emitted from the first collimating optical system 5A located at the upper left corner (+Z direction and -Y direction corner) of the first collimating optical system 5 is hatched with dense downward-right hatching. The light beam emitted from the first collimating optical system 5A is condensed at the position of the back focus 8 of the first condensing optical system 7a, forms a secondary light source 15a in a state where the light from each LED 3, 3, ... is imaged, and then travels while expanding the divergence angle and is guided to the second lens region 20a of the second collimating optical system 20.

[0040] Therefore, the light beam emitted from the first collimating optical system 5A located at the upper left corner in FIG. 4 forms an image 50A at the position of the lower right corner (the corner in the -Z direction and +Y direction) rotated by 180° on the projection surface installed downstream of the second lens region 20a, as shown in FIG. 5. For the purpose of indicating on the drawing that the image 50A is an image derived from the light beam emitted from the first collimating optical system 5A, similar to the light beam of the first collimating optical system 5A in FIG. 4, it is hatched with dense downward hatching on the right.

[0041] From the same perspective, the light beam (hatched with dense upward hatching on the right on the drawing) emitted from the first collimating optical system 5B located at the lower left corner (the corner in the -Z direction and -Y direction) of the light source unit 10b shown in FIG. 4 forms an image 50B at the position of the upper right corner (the corner in the +Z direction and +Y direction) rotated by 180° on the projection surface installed downstream of the second lens region 20b. In FIG. 5, the image 50B is hatched with dense upward hatching on the right, similar to the light beam of the first collimating optical system 5B in FIG. 4.

[0042] From the same perspective, the light beam (hatched with sparse downward hatching on the right on the drawing) emitted from the first collimating optical system 5C located at the upper right corner (the corner in the +Z direction and +Y direction) of the light source unit 10c shown in FIG. 4 forms an image 50C at the position of the lower left corner (the corner in the -Z direction and -Y direction) rotated by 180° on the projection surface installed downstream of the second lens region 20c. In FIG. 5, the image 50C is hatched with sparse downward hatching on the right, similar to the light beam of the first collimating optical system 5C in FIG. 4.

[0043] From the same perspective, the light beam emitted from the first collimating optical system 5D, which was located at the lower right corner (-Z direction and +Y direction corner) of the light source unit 10d shown in FIG. 4 (hatched with sparse upward-right hatching on the drawing), forms an image 50D at the position of the upper left corner (+Z direction and -Y direction corner) rotated by 180° on the projection plane installed downstream of the second lens region 20d. In FIG. 5, the image 50D is hatched with sparse upward-right hatching, similar to the light beam of the first collimating optical system 5D in FIG. 4.

[0044] That is, as shown in FIG. 4, when viewing the plurality of light source units 10, 10,... from the opposite direction (-X direction in this example) to the light traveling direction, by setting the arrangement mode of the first collimating optical system 5 provided in each light source unit 10, 10,... so that the first collimating optical system 5 is not arranged in the region near the center, as shown in FIG. 5, the light beam emitted from the second collimating optical system 20 will substantially show a circular shape.

[0045] Also, as shown in FIGS. 3 and 5, adjacent second lens regions provided in the second collimating optical system 20 are adjacent to each other via a linear boundary. Referring to FIG. 5, the second lens region 20a and the second lens region 20b are adjacent to each other via a linear boundary. The same applies to the second lens region 20a and the second lens region 20c, the second lens region 20b and the second lens region 20d, and the second lens region 20c and the second lens region 20d. In this way, by closely arranging adjacent second lens regions, the gap between the light beams emitted from each second lens region can be extremely reduced.

[0046] The light source device 1 shown in Fig. 1 includes a fly-eye integrator 40 as an example of an integrator optical system at the subsequent stage of the second condensing optical system 30. The position of the light incident surface of the fly-eye integrator 40 substantially coincides with the position of the back focus 31 of the second condensing optical system 30. As a result, the light from the secondary light sources 15, 15,... derived from the respective light source units 10, 10,... incident on the second condensing optical system 30 is collimated via the second collimating optical system 20 and then condensed onto the light incident surface of the fly-eye integrator 40.

[0047] Fig. 6 is a schematic drawing of the light source device 1 when the number of the light source units 10, 10,... is increased compared to Fig. 1. As shown in Fig. 6, the incident angle (full angle) θ1 of the light beam incident on the surface arranged at the position of the back focus 31 of the second condensing optical system 30, in other words, the incident angle (full angle) θ1 of the light beam incident on the fly-eye integrator 40 depends on the distance D1 from the center of the second collimating optical system 20. That is, the incident angle θ1 of the light beam incident on the fly-eye integrator 40 can be adjusted according to the arrangement mode of the second collimating optical system 20, and thus the arrangement mode of each light source unit 10, 10,.... Note that adjusting the distance D1 from the center of the second collimating optical system 20 leads to adjusting the distance from the center of each secondary light source 15, 15,.... Furthermore, the incident angle (full angle) θ1 of the light beam incident on the fly-eye integrator 40 can also be adjusted by adjusting the focal length of the second condensing optical system 30.

[0048] The fly-eye integrator 40 is configured by arranging a plurality of lens elements in a matrix. Due to its characteristics, the fly-eye integrator 40 has a limitation in the range of the incident angle that can be taken in inward depending on the shape of the lens elements. Here, for convenience, the incident angle of the light incident from the light incident surface of the fly-eye integrator 40 that can be guided to the light exit surface side of the fly-eye integrator 40 is described as the "effective capture angle".

[0049] The light beam emitted from the secondary light sources 15, 15, … and traveling through the second collimating optical system 20 and the second condensing optical system 30 is incident on the light incident surface of the fly-eye integrator 40. Here, among the light beams, for the light beams that have traveled through the portions having the same separation distance from the optical axis center, as schematically shown in FIG. 7, they are incident on the light incident surface of the fly-eye integrator 40 at the same incident angle θa.

[0050] FIG. 8 is a drawing showing a situation where a certain light Lb is incident on the lens element 41 constituting the fly-eye integrator 40 at an incident angle θb larger than the effective capture angle θL. A part of the light Lb cannot be captured into the fly-eye integrator 40, or even if it is captured into the fly-eye integrator 40, it is not converted into heat by being absorbed on the side surface without reaching the light exit surface, or it is transmitted through the side surface and exits or is reflected on the side surface to become stray light (light that cannot be used). In this case, a part of the light incident on the fly-eye integrator 40 cannot be made incident on the optical system at the subsequent stage of the fly-eye integrator 40. In this case, a part of the light emitted from the secondary light sources 15, 15, … cannot be used.

[0051] However, as described above with reference to FIGS. 4 to 5, the shape of the light beam emitted from the second collimating optical system 20 can be adjusted according to the arrangement mode of the first collimating optical systems 5, 5, … mounted on the light source units 10, 10, …. Therefore, by adjusting the arrangement mode of the first collimating optical systems 5, 5, … mounted on the light source units 10, 10, … according to the shape and the effective capture angle of the lens element 41 provided in the fly-eye integrator 40, the utilization efficiency of the light emitted from the light source units 10, 10, … can be improved.

[0052] [Another Embodiment] Hereinafter, another embodiment of the light source device according to the present invention will be described.

[0053] <1> FIG. 9 is a drawing schematically showing the structure of another embodiment of the light source device. As shown in FIG. 9, the LEDs 3, 3,... mounted on the light source unit 10a and the LEDs 3, 3,... mounted on another light source unit 10b may be arranged on different planes.

[0054] In the example shown in FIG. 9, the light emitted from the LEDs 3, 3,... mounted on the light source unit 10a is emitted in the +Z direction through the first collimating optical system 5, and the secondary light source 15a is generated by the first condensing optical system 7. Then, the light from this secondary light source 15a is reflected by the mirror 62 and then collimated by the second collimating optical system 20, and travels in the +X direction as collimated light and is guided to the second condensing optical system 30.

[0055] On the other hand, the light emitted from the LEDs 3, 3,... mounted on the light source unit 10b is emitted in the -X direction through the first collimating optical system 5, and then reflected by the mirror 61 and the traveling direction is converted to the +Z direction. Then, the secondary light source 15b is generated by the first condensing optical system 7. The light from the secondary light source 15b is collimated by the second collimating optical system 20, then reflected by the mirror 62, travels in the +X direction as collimated light, and is guided to the second condensing optical system 30.

[0056] Note that the example shown in FIG. 9 is merely an example.

[0057] <2> In the above embodiment, with reference to FIG. 4, the arrangement modes of the first collimating optical system 5 and the first condensing optical system 7 provided in each light source unit 10, 10,... were described. However, the arrangement mode of the first collimating optical system 5 shown in FIG. 4 is merely an example, and various variations are possible.

[0058] FIG. 10A is a plan view schematically showing an example of another configuration of the arrangement of the first collimating optical system 5 and the first condensing optical system 7 provided in each of the light source units 10, 10, …, and is denoted following FIG. 4. When the image projected when a projection surface is installed on the light emitting surface side of the second collimating optical system 20 is illustrated following FIG. 5, it becomes as shown in FIG. 10B.

[0059] FIG. 11A is a plan view schematically showing an example of another configuration of the arrangement of the first collimating optical system 5 and the first condensing optical system 7 provided in each of the light source units 10, 10, …, and is denoted following FIG. 4. In the examples shown in FIGS. 10A and 11A, when viewed in the X direction (in the Y-Z plane), each optical system is arranged such that the light emitted from the first collimating optical system 5 exceeds the outer edge (or the boundary of the light capture range) of the first condensing optical system 7. More specifically, in the examples shown in FIGS. 10A and 11A, the light emitted from the first collimating optical system 5 is arranged so as to exceed two sides of the outer edge of the first condensing optical system 7. When the image projected when a projection surface is installed on the light emitting surface side of the second collimating optical system 20 is illustrated following FIG. 5, it becomes as shown in FIGS. 10B and 11B. That is, each optical system is arranged such that the light beam passing through the outer edge of the first condensing optical system 7 is incident on the boundary line between the adjacent second lens regions of the second collimating optical system 20.

[0060] According to FIGS. 10B and 11B, compared with FIG. 5, the light density in the vicinity of the boundary line (the boundary line extending in the Z direction) between the lens regions adjacent in the Y direction and in the vicinity of the boundary line (the boundary line extending in the Y direction) between the lens regions adjacent in the Z direction is increased, and the decrease in luminance is suppressed.

[0061] Specifically, in FIG. 5, since the light beam from the first collimating optical system 5 is made to fit inside the outer edge of the first condensing optical system, all the light beams are taken into the fly-eye integrator, so it can be said that the light utilization efficiency is good. However, the form of FIG. 5 is not one in which the LEDs and the first collimating optical system 5 are arranged most densely, and the images 50 of the respective light beams are not arranged most densely either, so the light beam density is low. Also, even if an attempt is made to arrange them most densely, the light beam density near the boundary line is reduced, and as a result, the luminance is likely to decrease. On the other hand, in the configurations shown in FIGS. 10A to 11B, the images 50 of the respective light beams approach the most dense arrangement, and at that time, the decrease in the light beam density near the boundary line can be prevented, so the decrease in luminance can be suppressed.

[0062] FIG. 12A is a plan view schematically showing an example of another configuration of the arrangement mode of the first collimating optical system 5 and the first condensing optical system 7 provided in each light source unit 10, 10, …, and is labeled following FIG. 4. In the example shown in FIG. 12A, when viewed in the X direction (in the Y-Z plane), each optical system is arranged such that the light emitted from the first collimating optical system 5 exceeds the outer edge (or the boundary of the light capture range) of the first condensing optical system 7. More specifically, in the example shown in FIG. 12A, the light emitted from the first collimating optical system 5 is arranged so as to exceed one side of the outer edge of the first condensing optical system 7. In this case, when a projection surface is installed on the light emitting surface side of the second collimating optical system 20, the image projected is illustrated following FIG. 5 and is as shown in FIG. 12B. That is, each optical system is arranged such that the light beam passing through the outer edge of the first condensing optical system 7 is incident on the boundary line between adjacent second lens regions of the second collimating optical system 20.

[0063] In the case of the embodiment shown in FIG. 12A, the first collimating optical systems 5, 5,... included in each light source unit 10, 10,... can have the same shape. More specifically, according to FIG. 12A, by rotating and arranging the first collimating optical system 5 included in the light source unit 10a, it can be used as the first collimating optical system 5 included in other light source units (10b, 10c, 10d). As a result, it is not necessary to prepare a plurality of types of optical systems as the first collimating optical system 5, which leads to a reduction in the manufacturing cost per unit.

[0064] Furthermore, as shown in FIG. 13A, each light source unit 10, 10,... may be arranged in a state where it is rotated by substantially 120° each. FIG. 13A is a plan view schematically showing an example of another configuration of the arrangement mode of the first collimating optical system 5 and the first condensing optical system 7 included in each light source unit 10, 10,... and is denoted in accordance with FIG. 4. In this case, when a projection surface is installed on the light emitting surface side of the second collimating optical system 20, the image projected in this case is illustrated in accordance with FIG. 5 and is as shown in FIG. 13B.

[0065] In this way, the arrangement mode of the first collimating optical systems 5, 5,... included in each light source unit 10, 10,... can be variously changed. And by adjusting the arrangement mode of the first collimating optical systems 5, 5,..., the shape of the light beam traveling through the second collimating optical system 20 can be made to correspond to the shape of the light incident surface of the fly-eye integrator 40 in the subsequent stage from the plurality of secondary light sources 15, 15,... formed by being condensed by the first condensing optical system 7 after being emitted through the first collimating optical systems 5, 5,....

[0066] 〈3〉In each of the above embodiments, the case where the light source device 1 includes the fly-eye integrator 40 as the integrator optical system has been described. However, a rod integrator may be adopted as the integrator optical system instead of the fly-eye integrator 40.

[0067] 〈4〉The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for better understanding of the present invention, and are not necessarily limited to those having all the configurations described. The scope of the present invention is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Signs

[0068] 1: Light source device 3: LED 5: First collimating optical system 5a: First lens region 5A, 5B, 5C, 5D: First collimating optical system 7: First condensing optical system 7a, 7b, 7c, 7d: First condensing optical system 8: Back focus of the first condensing optical system 7 8a: Back focus of the first condensing optical system 7a 8b: Back focus of the first condensing optical system 7b 10: Light source unit 10a, 10b, 10c, 10d: Light source unit 15: Secondary light source 15a, 15b, 15c, 15d: Secondary light source 19a: Front focus of the second lens region 20a 19b: Front focus of the second lens region 20b 20: Second collimating optical system 20a, 20b, 20c, 20d: Second lens region 30: Second condensing optical system 31: Back focus of the second condensing optical system 40: Fly-eye integrator 41: Lens element of the fly-eye integrator 50A, 50B, 50C, 50D: Image 61, 62: Mirror

Claims

1. A plurality of light source units, each including a plurality of LEDs and a first collimating optical system including a plurality of first lens regions arranged corresponding to each of the plurality of LEDs at a subsequent stage of the plurality of LEDs and collimating light from a front focus of the first lens region, and a first condensing optical system for condensing the light emitted from the first collimating optical system; A second collimating optical system including a plurality of second lens regions arranged corresponding to each of the plurality of light source units at a subsequent stage of the plurality of light source units and collimating light from a front focus of the second lens region; A second condensing optical system for condensing the light emitted from the second collimating optical system; The plurality of light source units form discrete secondary light sources at back focus positions of the first condensing optical systems included in each of the plurality of light source units; A light source device, wherein positions of front foci of the plurality of second lens regions included in the second collimating optical system substantially coincide with positions of back foci of the first condensing optical systems included in the corresponding plurality of light source units.

2. The light source device according to claim 1, wherein when viewed from the side where light is emitted from the second collimating optical system, the plurality of second lens regions are arranged adjacent to each other via linear boundaries.

3. An integrator optical system for receiving the light emitted from the second condensing optical system; The light source device according to claim 1 or 2, wherein a light incident surface of the integrator optical system is arranged at a position substantially coinciding with a back focus of the second condensing optical system.

4. The light source device according to claim 3, wherein the integrator optical system is a fly-eye integrator in which a plurality of lens elements are arranged.

5. The light source device according to claim 4, wherein when a projection surface is arranged on a light emitting surface side of the second collimating optical system, a shape of an image projected on the projection surface corresponds to a shape of the lens element of the fly-eye integrator.

Images