JP6471900B2 - Light source device, exposure device - Google Patents

Description

  The present invention relates to a light source device, and more particularly, to a light source device including a plurality of LED elements. The present invention also relates to an exposure apparatus including such a light source device.

  Conventionally, an exposure apparatus has been used for fine processing using light. In recent years, exposure techniques have been developed in various fields, and are used for producing relatively large patterns and for three-dimensional fine processing among fine processing. More specifically, for example, an exposure technique is used for manufacturing an electrode pattern of an LED, a manufacturing process of MEMS (Micro Electro Mechanical Systems) represented by an acceleration sensor, and the like.

  In these exposure techniques, a discharge lamp with high brightness has been used as a light source for a long time. However, with recent progress in solid-state light source technology, it has been studied to use a light source having a plurality of LED elements arranged therein. As such a technique, for example, Patent Document 1 discloses an exposure apparatus in which a unit composed of a plurality of LED elements is used as a light source, and a fly-eye lens is disposed between the light source and a mask.

JP 2004-335953 A

  The LED element has a small amount of radiated light flux per chip as a light source for exposure. For this reason, in order to use as a light source device for exposure, it is necessary to collect the emitted light from a plurality of LED elements as much as possible. For this purpose, it is necessary to increase the number of LED elements arranged as light sources.

  The configuration of the light source device disclosed in Patent Document 1 will be described with reference to FIG. FIG. 14A is a diagram schematically showing a part of the light source device. As shown in FIG. 14A, the light source device includes a light source 100 including a plurality of LED elements (101, 102,...), A collimating lens 103, and a fly-eye lens 104. FIG. 14B is a partially enlarged view of FIG.

  The LED element 101 is located at the center of the optical axis, and the LED element 102 is located at the peripheral edge of the light source 100. A light ray L <b> 1 shown in FIG. 14 is light incident on the incident surface 121 of one lens 110 included in the fly-eye lens 104 out of the radiated light from the LED element 101. Similarly, the light ray L <b> 2 is light that is incident on the incident surface 121 of one lens 110 included in the fly-eye lens 104 among the light emitted from the LED element 102.

  A light beam L1 emitted from the LED element 101 located at the center of the optical axis is incident on the lens 110 parallel to the optical axis. On the other hand, the light beam L2 emitted from the LED element 102 disposed at a position away from the optical axis is incident on the lens 110 at an angle with respect to the optical axis. These lights are respectively imaged on the exit surface 122 of the lens 110 (IM101, IM102). FIG. 14C is a drawing schematically showing a state where an image is formed on the exit surface 122 of the lens 110.

  Light emitted from the emission surface 122 is incident on a subsequent optical system (not shown), and this light is used. That is, the emission surface 122 serves as a secondary light source. The luminance of the secondary light source is a value obtained by multiplying the luminance of the individual LED elements (101, 102,...) By the total area of the LED images (IM101, IM102,...) And dividing by the area of the exit surface 122. That is, in order to make the luminance of the emission surface 122 functioning as a secondary light source as high as possible, the total area of the LED image and the area of the emission surface 122 should be matched as much as possible. For this purpose, it is necessary to arrange the LED elements (101, 102,...) As closely as possible.

  However, as shown in FIG. 14, when the light source 100 is configured by arranging a plurality of LED elements (101, 102,...), Signal lines for supplying current to the LED elements (101, 102,...). And peripheral circuits such as switching elements are required. Therefore, practically, the LED elements (101, 102,...) Cannot be arranged without a gap. As a result, according to the conventional configuration, the luminance of the secondary light source (the emission surface of the fly-eye lens 104 in the configuration of FIG. 14) is lowered.

  In view of such a problem, an object of the present invention is to realize a light source device that includes a plurality of LED elements and suppresses a decrease in luminance. Another object of the present invention is to realize an exposure apparatus including such a light source device.

The light source device according to the present invention includes:
A plurality of LED elements;
A first optical system including a plurality of collimating lenses for collimating light emitted from the plurality of LED elements,
A second optical system that collects light emitted from the first optical system;
A light guide member having an incident surface disposed at a focal position of the second optical system;
The light guide member is an optical member that guides light incident from the incident surface to the exit surface while repeating reflection on the inner surface.

  As described above, the light emitted from one LED element has a lower luminance than the lamp. For this reason, when it is assumed that the light source is used for a light source that requires a lot of light, such as an exposure apparatus, it is important to collect the light from many LED elements without reducing the luminance as much as possible. .

  By the way, since it is indispensable for the LED element to have a wiring pattern for supplying power, the LED element itself cannot be placed in close contact as described above in the section “Problems to be Solved by the Invention”. . That is, when arranging a plurality of LED elements, it is necessary to leave a certain distance between adjacent LED elements. The region forming this interval constitutes a region that does not emit light (non-light emitting region). For this reason, even if a plurality of LED elements are simply arranged and the emitted light from each LED element is condensed, a non-light emitting region is inevitably generated. Therefore, simply condensing the light emitted from the plurality of LED elements causes a decrease in luminance on the irradiated surface.

  According to the above configuration, the light emitted from the plurality of LED elements is condensed after being collimated in the first optical system. Thereby, the light emitted from the first optical system forms a light beam having a large area on a plane orthogonal to the optical axis while maintaining the luminance as compared with the time immediately after being emitted from the LED element. Thereby, the space | interval of the light beams inject | emitted from each LED element can be narrowed, and the light source with few non-light-emitting areas is comprised. As a result, a light source device having higher brightness than the conventional one is realized.

  Furthermore, according to said structure, the 2nd effect that the illumination intensity distribution in an irradiation surface can be equalized is also implement | achieved. This point will be described. FIG. 1A is a schematic view of the LED element as viewed from above. The LED element 40 shown in FIG. 1A includes a light extraction part 41, an electrode part 42, and an element covering part 43. The light extraction portion 41 is usually composed of a semiconductor layer and corresponds to a light emitting region. The electrode portion 42 is made of a conductive material that does not transmit light, and this portion corresponds to a non-light emitting region.

  FIG. 1B shows a case where a plurality of LED elements having the shape shown in FIG. 1A are provided, and the light emitted from each LED element is condensed on a predetermined incident surface via the first optical system and the second optical system. It is the photograph of the image on the said entrance plane when. In the photograph of FIG. 1B, the presence of a dark part is confirmed in a partial region, but it can be seen that this dark part corresponds to the position of the electrode part 42 when compared with the drawing of FIG. 1A.

  That is, when light having an illuminance distribution as shown in FIG. 1B is irradiated onto the work as light for exposure, for example, exposure unevenness may occur on the work surface.

  Therefore, in the above configuration, the light condensed by the second optical system is made incident on the incident surface of the light guide member. The light guide member is an optical member that guides light incident from the incident surface to the exit surface while repeating reflection on the inner surface. As a result, the light incident in the light guide member is repeatedly reflected to mix light of various angle components and position components, so that the illuminance is more uniform on the exit surface of the light guide member than the incident surface. It becomes.

  That is, according to said structure, even when an LED element is used for a light source part, while achieving high brightness | luminance, the illumination intensity variation can be suppressed further. Therefore, it can be used as a light source for exposure that requires high-luminance light. Further, according to this configuration, the illuminance can be made uniform, so that exposure unevenness can be suppressed. In addition, this light guide member can be comprised with a rod integrator, for example.

The plurality of LED elements are arranged on a predetermined first plane,
The collimating lens is configured such that an area of an incident surface on which light emitted from the corresponding LED element is incident is larger than an area of a light emitting surface of the LED element,
When the first optical system is viewed in a direction orthogonal to the first plane, the interval between the outer edges of the plurality of adjacent collimating lenses may be smaller than the outer diameter of the collimating lens.

  By arranging the LED element and the collimating lens in this way, it is possible to collect as much light as possible from the plurality of LED elements and guide it to the incident surface of the rod integrator. Thereby, a light source with high luminance is realized.

  As a specific method for arranging the LED elements in this way, a method is assumed in which the LED elements are aligned and arranged so that a plurality of LED elements located at the outermost edge form a regular hexagonal shape or a square shape. Is done.

The incident surface of the light guide member is configured in a polygonal shape,
When the first plane is moved so as to be parallel to the incident surface of the light guide member, the number of the LED elements arranged on the second plane which is the first plane after the movement is the smallest. When the direction is the first direction, at least one of the second directions orthogonal to the first direction on the second plane is orthogonal to the sides constituting the incident surface on the incident surface of the light guide member. The plurality of LED elements may be arranged so as not to be parallel to the third direction.

  By adopting such a configuration, the types of angle components of light incident on the incident surface of the light guide member can be increased, and the effect of further reducing illuminance variation on the exit surface of the light guide member can be achieved. can get. The reason for this will be described later in the section “DETAILED DESCRIPTION”.

  In the above configuration, the plurality of LED elements may be arranged so that all the second directions are not parallel to the third direction. When it is set as such a structure, the effect of reducing the illuminance variation on the emission surface of the light guide member can be further enhanced.

Both the outer edge of the LED element and the incident surface of the light guide member have a rectangular shape,
On the second plane, the two sides of the square formed by the outer edge of the LED element may be parallel to the two sides of the square formed by the incident surface of the light guide member.

  According to the said structure, the light inject | emitted from the light emission area | region of each LED element can be guide | induced to the entrance plane of a light guide member without leaking.

  In the above configuration, each LED element may have the same shape.

  ADVANTAGE OF THE INVENTION According to this invention, in the structure provided with a some LED element, the light source device which suppressed the fall of the brightness | luminance is implement | achieved.

It is a schematic diagram when an LED element is seen from the upper surface. It is the photograph of the image on the surface which condensed the light inject | emitted from the LED element shown to FIG. 1A, after collimating. It is drawing which shows typically the optical system of the light source device of 1st embodiment. It is drawing which shows typically a mode when the light source part side is seen to a Z direction from between the 1st optical system and the 2nd optical system in the light source device of 1st embodiment. It is drawing which shows typically a mode when the light source part side is seen to a Z direction from between the 1st optical system and the 2nd optical system, when the arrangement | positioning space | interval of an LED element is wide. It is drawing which shows typically the optical system of the light source device in case the LED element is arrange | positioned in the aspect of FIG. In the light source device of 1st embodiment, it is another drawing which shows typically a mode when the light source part side is seen to a Z direction from between a 1st optical system and a 2nd optical system. In the light source device of 2nd embodiment, it is drawing which shows typically a mode when the light source part side is seen to a Z direction from between 1st optical systems and 2nd optical systems. FIG. 4 is a drawing schematically showing an optical path of light emitted from the center position of each LED element when LED elements are arranged in the manner shown in FIG. 3. FIG. 4 is a drawing schematically showing an optical path of light emitted from the center position of each LED element when LED elements are arranged in the manner shown in FIG. 3. 8 is a drawing schematically showing an optical path of light emitted from the center position of each LED element when the LED elements are arranged in the mode shown in FIG. 7. 8 is a drawing schematically showing an optical path of light emitted from the center position of each LED element when the LED elements are arranged in the mode shown in FIG. 7. It is a graph which shows the illumination intensity distribution of the light irradiated to the optical system of the back | latter stage of a rod integrator at the time of arrange | positioning an LED element in the aspect shown in FIG. It is a graph which shows the illumination intensity distribution of the light irradiated to the optical system of the back | latter stage of a rod integrator at the time of arrange | positioning an LED element in the aspect shown in FIG. In the light source device of 3rd embodiment, it is drawing which shows typically a mode when the light source part side is seen to a Z direction from between 1st optical systems and 2nd optical systems. It is drawing which shows typically the image of the light on the entrance plane of a rod integrator at the time of arrange | positioning an LED element in the aspect shown in FIG. It is drawing which shows typically the image of the light on the entrance plane of a rod integrator at the time of arrange | positioning an LED element in the aspect shown in FIG. It is drawing which shows the structure of an exposure apparatus typically. It is drawing which shows typically a part of structure of the conventional light source device.

  The light source device and exposure apparatus of the present invention will be described below with reference to the drawings. In addition, the dimension ratio in each figure does not necessarily correspond with an actual dimension ratio.

[First embodiment]
FIG. 2 is a drawing schematically showing an optical system of the light source device of the first embodiment. The light source device 1 includes a light source unit 2, a first optical system 5, a second optical system 7, and a rod integrator 9.

  The light source unit 2 includes a plurality of LED elements 3. Each of the plurality of LED elements 3 has a structure as shown in FIG. 1A, for example. Each LED element 3 is arranged on a predetermined plane.

  The first optical system 5 is an optical system that collimates the light emitted from the plurality of LED elements 3, and is configured by arranging a plurality of collimating lenses 6 corresponding to the LED elements 3.

  The second optical system 7 is an optical system that condenses the light emitted from the first optical system 5 at the focal point 7 f of the second optical system 7.

  The rod integrator 9 is arranged such that the incident surface 9a is positioned at the focal point 7f of the second optical system 7. However, in this specification, “arranged at the focal position” means that the lens is moved by a distance of ± 10% in a direction parallel to the optical axis 11 with respect to the focal distance, in addition to the case where it completely coincides with the focal position. It is assumed that the concept includes a position. Note that the optical axis 11 in FIG. 2 is an axis orthogonal to the incident surface 9 a of the rod integrator 9.

  The rod integrator 9 has a function of uniformizing the illuminance distribution of light on the exit surface 9b by guiding the light incident on the entrance surface 9a to the exit surface 9b while repeating total reflection on the side surface. It is an example of (light guide). Such a light guide member includes, for example, a columnar member made of a light-transmitting material such as glass or resin, a hollow member whose inner surface is formed of a reflecting mirror, and the like. The latter configuration is sometimes called a light tunnel. In addition, the light guide member may be configured by dividing a plurality of optical paths in a direction parallel to the optical axis.

  In the following description, a direction parallel to the optical axis 11 is defined as a Z direction, and a plane orthogonal to the Z direction is described as an XY plane.

  FIG. 3 is a drawing schematically showing a state when the light source unit 2 side is viewed in the Z direction (the optical axis 11 direction) from between the first optical system 5 and the second optical system 7. As shown in FIG. 3, the plurality of LED elements 3 are regularly arranged on a predetermined plane (here, the XY plane), and collimating lenses are arranged at positions facing each LED element 3 in the Z direction. 6 is arranged. In the example of FIG. 3, each LED element 3 which comprises an outer edge part comprises a regular hexagon, and each LED element 3 is arranged in the X direction and the Y direction. In addition, in FIG. 3, the code | symbol 51-69 is attached | subjected about each LED element 3, for convenience of explanation, respectively. If it demonstrates with reference to this code | symbol, each LED element (51,52,53,57,62,66,69,68,67,63,58,54) which comprises an outer edge part comprises a regular hexagon. Yes.

  In FIG. 2, the light emitted from the center of each LED element 3 spreads to the periphery of the exit surface of the collimating lens 6 and then converted into parallel light, as schematically illustrated with light rays. That is, the luminance on the exit surface of the collimating lens 6 is equal to the luminance on each LED element 3. For this reason, if a gap is generated between the adjacent collimating lenses 6, the luminance value of the secondary light source constituted by the exit surface side of the collimating lens 6 group (that is, the first optical system 5) is the amount of the gap. Only drops. Therefore, in order to maintain the luminance of each LED element 3 as much as possible, it is preferable to make the adjacent collimating lenses 6 as close as possible. From this point of view, in this embodiment, the collimating lenses 6 are closely arranged in a regular hexagonal shape. The collimating lens 6 is configured such that the area of the incident surface 6 a is larger than the area of the light emitting surface of the corresponding LED element 3.

  By arranging the plurality of LED elements 3 in a manner as shown in FIG. 3, many LED elements 3 can be densely packed in a limited area. Thereby, the emitted light from many LED elements 3 can be condensed by the second optical system 7. As shown in FIG. 2, for example, a light beam 20 a formed by light emitted from a certain LED element 3 through the second optical system 7 and light emitted from another LED element 3 formed through the second optical system 7. The distance d from the light beam 20b can be shortened as much as possible. That is, the light incident on the incident surface 9a of the rod integrator 9 can be made dense.

  As described above with reference to FIG. 1A, the LED element 3 has the electrode portion 42, and although not shown, a wiring for supplying power to the electrode portion 42 is separately required. As described above, when the LED elements 3 are arranged, it is inevitable to secure an area for routing the wiring. Therefore, a space 21 (see FIG. 3) is not provided between the adjacent LED elements 3. There is a circumstance that does not get.

  For example, as shown in FIG. 4, consider a case where the LED elements 3 are arranged with a wide interval 21. FIG. 4 illustrates a case where the LED element 3 ′ and the collimating lens 6 ′ corresponding to the LED element 3 ′ are arranged in such a manner that there is a margin that can be arranged. When the LED element 3 is arranged in this way, as shown in FIG. 5, a light beam 20 a formed by light emitted from a certain LED element 3 through the second optical system 7 and light emitted from another LED element 3 are emitted. The distance d extends to the light beam 20b forming the second optical system 7. In this case, as described above, the luminance value on the emission side of the first optical system 5 is reduced as compared with the configuration of FIG. Moreover, since the rod integrator 9 advances the light while maintaining the angle component of the light incident on the incident-side end surface 9a, an illuminance distribution is generated on the exit-side end surface 9b side.

  As described above, the rod integrator 9 reflects the light along the longitudinal direction (here, the Z direction) while maintaining the angle at which the light incident on the incident surface 9a travels by totally reflecting the light on the inner surface. Is configured to propagate. That is, the rod integrator 9 has a function of uniforming the illuminance distribution on the exit surface 9b while maintaining the angle of the light incident on the entrance surface 9a. Therefore, even in the configurations of FIGS. 4 and 5, the illuminance distribution is made more uniform on the exit surface 9 b of the rod integrator 9 than on the entrance surface 9 a. However, in the configuration shown in FIGS. 4 and 5, the angular component of the light incident on the incident surface 9 a of the rod integrator 9 is missing, which disadvantageously works to make the illuminance distribution uniform on the exit surface 9 b. In order to make these uniform, it is necessary to ensure a large number of reflections in the rod integrator 9. As a result, the length of the rod integrator 9 must be increased.

  However, when the LED elements 3 are arranged as shown in FIG. 3, the interval 21 between the LED elements 3 is narrowed, so that the interval between the light beams emitted from the LED elements 3 as shown in FIG. 2. d can be made as narrow as possible. As a result, light having no missing angle component can be condensed on the incident surface 9a of the rod integrator 9, and the illuminance distribution of the light on the exit surface 9b of the rod integrator can be made more uniform.

  The arrangement method of the LED elements 3 described above with reference to FIG. 3 is merely an example, and the arrangement method is appropriately selected. For example, as shown in FIG. 6, it is assumed that each LED element 3 constituting the outer edge portion has a substantially square shape, and each LED element 3 is arranged in alignment in the X direction and the Y direction. it can. Also in the embodiment of FIG. 6, the LED elements 3 and the collimating lenses 6 can be arranged densely. Even in the case where the LED element 3 is arranged in this way, light with a small missing angle component can be condensed on the incident surface 9a of the rod integrator 9 as in the case of FIG.

[Second Embodiment]
The light source device of the second embodiment will be described. 2nd embodiment differs in the arrangement | positioning method of each LED element 3 compared with 1st embodiment.

  FIG. 7 shows the arrangement method of the LED elements 3 in the second embodiment, following FIG. In the LED element 3 shown in FIG. 7, a plurality of LED elements 3 are arranged in alignment in directions c1 and c2, both non-parallel to the X direction and the Y direction. The fact that the illuminance distribution on the exit surface 9b of the rod integrator 9 is made more uniform than in the case where the LED elements 3 are arranged in the manner shown in FIG.

  8A and 8B show the case where the light emitted in the Z direction from the central position of each LED element 3 is incident on the second optical system 7 when the LED elements 3 are arranged in the manner shown in FIG. An optical path to be incident on the rod integrator 9 is schematically shown. This optical path corresponds to the optical axis indicated by the light emitted from each LED element 3 between the second optical system 7 and the rod integrator 9. 8A is a schematic drawing when the optical system is viewed in the X direction, and FIG. 8B is a schematic drawing when the optical system is viewed in the Y direction.

  When the LED elements 3 are arranged in a manner as shown in FIG. 3, each LED element 3 shows nine different Y coordinates (Y1 to Y9) on the XY plane. More specifically, these Y coordinates are Y1 indicated by the LED element 62, Y2 indicated by the LED elements 57 and 66, Y3 indicated by the LED elements 53, 61 and 69, Y4 indicated by the LED elements 56 and 65, and the LED element 52. Y5 indicated by LED elements 55 and 64, Y7 indicated by LED elements 51, 59 and 67, Y8 indicated by LED elements 54 and 63, and Y9 indicated by LED element 58.

  The light emitted from the LED elements 3 indicating different Y coordinates is incident on the incident surface 7a of the second optical system 7 at different Y coordinates. That is, the light emitted from the LED element 58 whose Y coordinate value is Y9 is incident on the position of the largest Y coordinate on the incident surface 7a of the second optical system 7. This light is incident on the incident surface 9a of the rod integrator 9 as light having the optical axis 31Y9.

  Similarly, the light emitted from the LED elements 54 and 63 whose Y coordinate value is Y8 has the largest Y coordinate next to the light emitted from the LED element 58 on the incident surface 7a of the second optical system 7. Incident on the position. This light is incident on the incident surface 9a of the rod integrator 9 as light having the optical axis 31Y8.

  That is, the light having the optical axis 31Y9 shown in FIG. 8A is emitted from one of the LED elements 58 whose Y coordinate value indicates Y9. The light having the optical axis 31Y8 shown in FIG. 8A is emitted from the two LED elements 54 and 63 whose Y coordinate value indicates Y8. The same applies hereinafter.

  The light having the optical axis 31Y7 shown in FIG. 8A is emitted from the three LED elements 51, 59, and 67 whose Y coordinate values indicate Y7. The light having the optical axis 31Y6 shown in FIG. 8A is emitted from the two LED elements 55 and 64 in which the value of the arranged Y coordinate indicates Y6.

  The light having the optical axis 31Y5 shown in FIG. 8A is emitted from the three LED elements 52, 60, and 68 whose Y coordinate values indicate Y5. The light having the optical axis 31Y4 shown in FIG. 8A is emitted from two LED elements 56 and 65 in which the arranged Y coordinate value indicates Y4.

  The light having the optical axis 31Y3 shown in FIG. 8A is emitted from the three LED elements 53, 61, and 69 whose Y coordinate values indicate Y3. The light having the optical axis 31Y2 shown in FIG. 8A is emitted from the two LED elements 57 and 66 whose Y coordinate value is Y2. The light having the optical axis 31Y1 shown in FIG. 8A is emitted from one of the LED elements 62 whose Y coordinate value indicates Y1.

  As shown in FIG. 8A, the incident surface 9a of the lot inlator 9 increases as the position of the light incident on the incident surface 7a of the second optical system 7 moves away from the optical axis 11 of the second optical system 7 in the ± Y direction. The incident light has a large incident angle in the Y direction. FIG. 8A shows an example of light incident symmetrically in the Y direction with respect to the optical axis 11 of the second optical system 7 if the incident angles in the Y direction on the incident surface 9a of the lot inlator 9 are equal. Then, it can be said that there are five types of incident angles to the rod integrator 9. That is, the light having the optical axis 31Y9 (or 31Y1), the light having the optical axis 31Y8 (or 31Y2), the light having the optical axis 31Y7 (or 31Y3), and the optical axis 31Y6 (or 31Y4) are arranged in descending order of the incident angle. Light and light having an optical axis 31Y5. And the number of the LED elements 3 which are emitting these lights is 2, 4, 6, 4, 3 in order.

  Similarly, the X coordinate of each LED element 3 is also examined. When the LED elements 3 are arranged in a manner as shown in FIG. 3, each LED element 3 shows five different X coordinates (X1 to X5) on the XY plane. More specifically, these X coordinates are indicated by X1 indicated by LED elements 51, 52 and 53, X2 indicated by LED elements 54, 55, 56 and 57, and LED elements 58, 59, 60, 61 and 62. X3, X4 indicated by the LED elements 63, 64, 65, and 66, and X5 indicated by the LED elements 67, 68, and 69.

  Light emitted from the LED elements 3 indicating different X coordinates is incident on the incident surface 7a of the second optical system 7 at different X coordinate positions. That is, the light emitted from the LED elements 67, 68 and 69 whose X coordinate value is X5 is incident on the position of the largest X coordinate on the incident surface 7 a of the second optical system 7. This light is incident on the incident surface 9a of the rod integrator 9 as light having the optical axis 31X5.

  That is, the X coordinate can be discussed similarly to the Y coordinate. The light having the optical axis 31X5 shown in FIG. 8B is emitted from three LED elements 67, 68, and 69 in which the value of the arranged X coordinate indicates X5. The light having the optical axis 31X4 shown in FIG. 8A is emitted from four LED elements 63, 64, 65, and 66 in which the X coordinate values arranged indicate X4.

  The light having the optical axis 31X3 shown in FIG. 8B is emitted from five LED elements 58, 59, 60, 61, and 62 in which the value of the arranged X coordinate indicates X3. Light having the optical axis 31X2 shown in FIG. 8B is emitted from four LED elements 54, 55, 56, and 57 in which the value of the arranged X coordinate indicates X2. The light having the optical axis 31X1 shown in FIG. 8B is emitted from the three LED elements 51, 52, and 53 whose X coordinate values are X1.

  As shown in FIG. 8B, the incident surface 9a of the lot inlator 9 increases as the position of light incident on the incident surface 7a of the second optical system 7 moves away from the optical axis 11 of the second optical system 7 in the ± X direction. The incident light has a large incident angle in the X direction. FIG. 8B shows an example of light incident symmetrically in the X direction with respect to the optical axis 11 of the second optical system 7 if the incident angles in the X direction on the incident surface 9a of the lot inlator 9 are equal. Then, it can be said that there are three types of incident angles to the rod integrator 9. That is, the light having the optical axis 31X5 (or 31X1), the light having the optical axis 31X4 (or 31X2), and the light having the optical axis 31X3 in descending order of the incident angle. And the number of the LED elements 3 which are emitting these lights is 6, 8, and 5 in order.

  The greater the number of LED elements 3 that have emitted the light incident on the incident surface 9a of the rod integrator 9 with the same angle, the higher the amount of light indicating the angle component. That is, if the amount of light varies greatly according to the incident angle with respect to the incident surface 9a, an illuminance distribution according to the intensity variation of the angle component is generated on the exit surface 9b. In the arrangement mode of FIG. 3, it is considered that the illuminance distribution is generated on the exit surface 9 b of the rod integrator 9 because the amount of light according to the incident angle is different in each of the X direction and the Y direction. It is done. In other words, in order to make the illuminance as uniform as possible on the exit surface 9 b of the rod integrator 9, it is preferable to make the intensity of light showing different incident angles with respect to the entrance surface 9 a of the rod integrator 9 as uniform as possible. It is done.

  9A and 9B show the case where the light emitted in the Z direction from the central position of each LED element 3 is incident on the second optical system 7 when the LED elements 3 are arranged in the manner shown in FIG. An optical path to be incident on the rod integrator 9 is schematically shown. FIG. 9A is a schematic drawing when the optical system is viewed in the X direction, and FIG. 9B is a schematic drawing when the optical system is viewed in the Y direction.

  When the LED elements 3 are arranged in a manner as shown in FIG. 7, unlike the case of FIG. 3, each LED element 3 has 19 different types of Y coordinates (Y11 to Y29) and different 19 on the XY plane. The X coordinate (X11-X29) of the kind is shown. In the example of FIG. 7, the Y coordinate and the X coordinate are different for the arrangement positions of all the LED elements 3. Therefore, as shown in FIG. 9A, the light emitted from each LED element 3 is incident on the position of different Y coordinates with respect to the incident surface 7 a of the second optical system 7. For example, light emitted from the LED element 59 whose Y coordinate value is Y25 enters the incident surface 9a of the rod integrator 9 as light having the optical axis 31Y25. Further, as shown in FIG. 9B, the light emitted from each LED element 3 is incident on the X-coordinate position with respect to the incident surface 7 a of the second optical system 7. For example, light emitted from the LED element 59 whose X coordinate value is X19 enters the incident surface 9a of the rod integrator 9 as light having the optical axis 31X19.

  In the case of the arrangement mode shown in FIG. 3, there are a plurality of LED elements 3 emitting light incident on the incident surface 9 a of the lot inlator 9 at the same angle, and the number of these LED elements 3 varies depending on the angle. Had. As a result, the illuminance distribution according to the incident angle was present on the exit surface 9 b of the lot inlator 9.

  However, when the arrangement form as shown in FIG. 7 is adopted, the incident angle of the light emitted from each LED element 3 on the emission surface 9b of the lot inlator 9 can be dispersed more than the arrangement form shown in FIG. it can. This means that the number of LED elements 3 emitting light incident on the incident surface 9a of the lot inlator 9 at the same angle can be made uniform. That is, according to the arrangement mode of FIG. 7, an effect of reducing the illuminance distribution on the exit surface 9 b of the lot inlator 9 can be obtained.

  FIG. 10A is a graph showing the illuminance distribution of light applied to the optical system at the subsequent stage of the rod integrator 9 when the LED element 3 is actually arranged in the manner shown in FIG. FIG. 10B is a graph showing the illuminance distribution of light applied to the optical system downstream of the rod integrator 9 when the LED element 3 is actually arranged in the manner shown in FIG. 10A and 10B match the illuminance distribution on the exit surface 9b of the rod integrator 9.

  According to FIG. 10A, it can be seen that the illuminance distribution is higher in the X direction than in the Y direction on the exit surface 9 b of the rod integrator 9. As described above with reference to FIG. 8A and FIG. 8B, the incident angle to the rod integrator 9 is less in the X direction than in the Y direction, and thus the intensity variation of light at each angle increases. It is thought that it represents.

  On the other hand, according to FIG. 10B, it can be seen that the illuminance can be made uniform in the X direction and the Y direction on the exit surface 9 b of the rod integrator 9. Also from this, the variation in illuminance on the exit surface 9b of the rod integrator 9 is made by making the incident angle of the light to the rod integrator 9 as different as possible and minimizing the difference in intensity between the lights having different incident angles. It turns out that the effect which further reduces is acquired. That is, according to the configuration of the present embodiment, it is possible to realize light with a uniform illuminance distribution while suppressing a decrease in luminance of light emitted from the light source unit 2.

[Third embodiment]
A light source device according to a third embodiment will be described. 3rd embodiment differs in the arrangement | positioning method of each LED element 3 compared with 2nd embodiment. FIG. 11 shows the arrangement method of the LED elements 3 in the third embodiment, following FIG. As in FIG. 7, the LED element 3 shown in FIG. 11 has a plurality of LED elements 3 aligned in directions c1 and c2, which are both non-parallel to the X direction and the Y direction. However, the directions of the sides of the LED elements 3 are arranged so as to be parallel to the X direction and the Y direction.

  FIG. 12A is a drawing schematically showing an image formed on the incident surface 9a of the rod integrator 9 when the LED element 3 is arranged as shown in FIG. 7 as described in the second embodiment. 12B is a drawing schematically showing an image formed on the incident surface 9a of the rod integrator 9 when the LED element 3 is arranged in the manner shown in FIG.

  As shown in FIG. 12A, in the case of the arrangement shown in FIG. 7, since the LED element 3 itself is also inclined in the X direction and the Y direction, the image 9L on the incident surface 9a of the rod integrator 9 is inclined. As a result, the region of the image 9L protrudes on the incident surface 9a. Since the light in the protruding area is not used effectively, the light use efficiency is lowered as a result.

  On the other hand, in the case of the arrangement mode shown in FIG. 9, the LED element 3 itself is arranged without being inclined. Therefore, as shown in FIG. 12B, the image 9 </ b> L formed on the incident surface 9 a It becomes parallel to the side which 9a comprises. As a result, the light can be utilized to the maximum extent by only condensing the plurality of LED elements 3 within a range that can be taken into the rod integrator 9.

  Further, in the case of the arrangement mode shown in FIG. 7, as shown in FIG. 12A, an illuminance distribution is generated between the region of the image 9L and the region where no image is formed on the incident surface 9a. On the other hand, in the arrangement mode shown in FIG. 9, as shown in FIG. 12B, the ratio of the area of the region of the image 9L to the region of the incident surface 9a can be increased. As a result, the illuminance distribution on the exit surface 9b of the rod integrator 9 can be made more uniform as compared with the arrangement shown in FIG.

[Fourth embodiment]
FIG. 13 is a drawing schematically showing the configuration of the exposure apparatus. An exposure apparatus 19 shown in FIG. 13 includes the light source device 1 according to any one of the above-described embodiments. A projection optical system 15 and a mask 16 are provided at the subsequent stage of the rod integrator 9, and a projection lens 17 is provided as necessary. A mask 16 is placed at a position projected by the projection optical system 15, and a photosensitive substrate 18 to be a target for printing a pattern image of the mask 16 is placed after the mask 16. In this state, when light is emitted from the light source unit 2, the light is collected by the second optical system 7, and then irradiated to the projection optical system 15 as light whose illuminance distribution is uniformed by the rod integrator 9. Is done. The projection optical system 12 projects the pattern image of the mask 16 onto the photosensitive substrate 18 directly or via the projection lens 17.

  The exposure device 19 includes the light source device 1 described in each of the above embodiments, whereby exposure can be performed using light with improved variation in illuminance as compared with the related art, and uneven exposure is suppressed.

[Another embodiment]
Hereinafter, another embodiment will be described.

  <1> In the second embodiment, the case where the arrangement directions c1 and c2 of the LED elements 3 are inclined by 15 ° from the X and Y directions, respectively, has been described. However, the angle of inclination is not limited to 15 °.

  As described above, when the LED element 3 is arranged as shown in FIG. 3, the number of coordinates is smaller in the X direction than in the Y direction, and illuminance variation occurs in the X direction on the exit surface 9 b of the rod integrator 9. . In the example of FIG. 3, nine lines parallel to the X direction can be drawn (showing nine Y coordinates) as lines passing through each LED element 3, while only five lines parallel to the Y direction can be drawn (5 Two X coordinates are shown). That is, when the LED elements 3 are arranged as shown in FIG. 3, nine rows of LED elements are arranged in the X direction, and five rows of LED elements are arranged in the Y direction.

  In such a configuration, the direction orthogonal to the direction in which the LED elements 3 are arranged in a small number (the Y direction in FIG. 3), that is, the X direction and the direction of the side constituting the incident surface 9a of the rod integrator 9 are parallel. However, the arrangement of the LED elements 3 is changed. Thereby, the light intensity distribution for each angle on the incident surface 9a of the rod integrator 9 is suppressed, and the illuminance on the exit surface 9b can be made uniform. More specifically, the LED elements 3 are arranged so that the direction orthogonal to the direction in which the number of the LED elements 3 is arranged is not parallel to the direction of the side constituting the incident surface 9a of the rod integrator 9. preferable.

  Furthermore, in the above embodiment, the description has been given on the assumption that the shape of the incident surface 9a of the rod integrator 9 is rectangular. However, the shape of the entrance surface 9a of the rod integrator 9 is not limited to a rectangle, and a shape such as a triangle, a right triangle, and a regular hexagon can be employed. Here, the light incident on the rod integrator 9 is mixed with the light while being repeatedly reflected on the inner surface and guided to the exit surface 9b. In view of this point, on the incident surface 9a of the rod integrator, a direction orthogonal to the side constituting the incident surface 9a and a direction orthogonal to the direction in which the LED elements 3 are arranged in a small number (FIG. 3). The illuminance on the exit surface 9b of the rod integrator 9 can be made uniform by arranging the LED elements 3 so that they are not parallel to the X direction in this example.

  <2> In the second embodiment, the case where the LED element 3 and the incident surface 9a of the rod integrator 9 are both present on the XY plane has been described. However, it may be possible to change the traveling direction of the light by arranging, for example, a reflection optical system between the light source unit 2 and the rod integrator 9. Under this configuration, the LED element 3 and the incident surface 9a of the rod integrator 9 do not necessarily exist on a parallel plane.

  In such a case, the LED element 3 is arranged on a virtual plane obtained by moving the plane on which the LED element 3 is arranged so as to be parallel to the incident surface 9a of the rod integrator 9 in the same manner as in the above-described embodiment. 3 may be arranged. A plane on which the LED element 3 is disposed is referred to as a “first plane”, and a plane configured when the first plane is moved so as to be parallel to the incident surface 9 a of the rod integrator 9 is referred to as a “second plane”. And The direction in which the number of LED elements arranged on the second plane is the smallest is not parallel to the direction orthogonal to the side constituting the incident surface 9a on the incident surface 9a of the rod integrator 9. By arranging the LED element 3, the same effect as the configuration of the second embodiment can be obtained.

  Depending on the arrangement mode of the LED elements 3, there may be a plurality of directions in which the number of the LED elements 3 is the smallest. In this case, in particular, all the directions orthogonal to the direction in which the number of LED elements arranged on the second plane is the smallest are the sides constituting the incident surface 9a on the incident surface 9a of the rod integrator 9. It is more preferable to arrange the LED elements 3 so that they are not parallel to the direction orthogonal to the direction. By configuring in this way, the effect of making the illuminance distribution uniform on the exit surface 9b of the rod integrator 9 can be further enhanced.

1: Light source device 2: Light source unit 3: LED element 5: First optical system 6: Collimating lens 6a: Collimating lens incident surface 7: Second optical system 7a: Second optical system incident surface 7f: Second optical system 9: Rod integrator 9a: Entrance surface of rod integrator 9b: Exit surface of rod integrator 9L: Image of light on entrance surface of rod integrator 11: Optical axis 15: Projection optical system 16: Mask 17: Projection lens 18: Photosensitive substrate 19: Exposure apparatus 20a, 20b: Light flux 21: Interval 31X1-31X5: Optical axis of light emitted from the LED element 31X11-31X29: Optical axis of light emitted from the LED element 31Y1-31Y9: From the LED element Optical axis of emitted light 31Y11-31Y29: Emitted from LED element Optical axis 40: LED element 41: Light extraction part 42: Electrode part 43: Element covering part 51-69: LED element 100: Light source 101, 102: LED element 103: Collimating lens 104: Fly eye lens 110: One lens constituting a fly-eye lens 121: an incident surface of the lens 110 122: an exit surface of the lens 110 IM101: an image of the LED element 101 IM102: an image of the LED element 102

Claims (5)

A plurality of LED elements;
A first optical system including a plurality of collimating lenses for collimating light emitted from the plurality of LED elements,
A second optical system that collects light emitted from the first optical system;
A light guide member having an incident surface disposed at a focal position of the second optical system;
The light guide member has a light incident from the incident surface, Ri optical member der leading to the exit surface while repeating reflection at the inner surface,
The plurality of LED elements are arranged on a predetermined first plane,
The collimating lens is configured such that an area of an incident surface on which light emitted from the corresponding LED element is incident is larger than an area of a light emitting surface of the LED element,
When the first optical system is viewed in the direction perpendicular to the first plane, the interval between the outer edges of the plurality of adjacent collimating lenses is narrower than the outer diameter of the collimating lens,
The incident surface of the light guide member is configured in a polygonal shape,
When the first plane is moved so as to be parallel to the incident surface of the light guide member, the arrangement number of the LED elements arranged on the second plane which is the first plane after the movement is the largest. When the first direction is a small direction, at least one of the second directions orthogonal to the first direction on the second plane is orthogonal to the side constituting the incident surface on the incident surface of the light guide member. The plurality of LED elements are arranged so as not to be parallel to the third direction . All the second direction, so as not to be parallel to the third direction, the light source apparatus according to claim 1, wherein the plurality of LED elements are arranged. Both the outer edge of the LED element and the incident surface of the light guide member have a rectangular shape,
Two sides of the square outer edge of the LED elements on the second plane to constitute the, according to claim 1 or 2, characterized in that it is parallel to two sides of the square incident surface of the light guide member constitutes Light source device. The light source device according to any one of claims 1 to 3, characterized in that the light guide member is constituted by a rod integrator. An exposure apparatus for transferring a mask pattern onto a photosensitive substrate,
The light source device according to any one of claims 1 to 4 ,
An exposure apparatus comprising: a projection optical system that irradiates the mask with light from an emission surface of the light guide member and projects a pattern image of the mask onto the photosensitive substrate.

Images