JP2013069860A - Led light source device and exposure equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide exposure equipment using an LED light source device, achieving high illuminance.SOLUTION: An LED light source device 20 used in exposure equipment and others, includes: an LED unit 30 in which LEDs 40A to 40F are arranged on side faces of a support member 32, respectively; and a reflection part 12 constituted by reflectors 12A to 12F. The reflectors 12A to 12F are not formed integrally, and are attached individually to and along the side faces having the LEDs 40A to 40F arranged thereon.

Description

  The present invention relates to an exposure apparatus that forms a pattern on a substrate or the like, and more particularly to a light source apparatus that uses LEDs.

  In the exposure apparatus, pattern light is projected onto a substrate coated with a photosensitive material such as a photoresist to form a pattern on the photosensitive material. For example, when a DMD (Digital Micro-mirror Device) in which micromirrors are two-dimensionally arranged is used, pattern light is generated by controlling each micromirror based on pattern data.

  As a light source device of an exposure apparatus, a light source device using a plurality of LEDs instead of a discharge lamp is known. In this case, each light emitting diode is ON / OFF controlled in accordance with an exposure operation performed at regular time intervals, and repeatedly turned on and off (see Patent Document 1).

  On the other hand, in a projection device such as a projector, an LED light source device using a reflector having a plurality of partial ellipsoids obtained by dividing a spheroid in a radial shape as a reflection surface is known (see Patent Document 2). In this structure, an LED unit in which a plurality of LEDs are installed on the front and back sides of a plate-like support member and a reflector in which a plurality of reflecting surfaces are integrally formed are attached to a holder. An LED is disposed at the focal position of each reflecting surface that is a surface.

JP 2003-057832 A JP 2011-023375 A

  A light source device used in an exposure apparatus must emit light with as high a light intensity as possible in order to improve throughput. Since the light emission intensity of one LED is much smaller than that of a light source such as a discharge lamp or a laser, it is necessary to accurately arrange a large number of LEDs at the focal position of the reflecting surface.

  However, when attaching a reflector in which a plurality of reflecting surfaces are integrated, it is difficult to accurately arrange all LEDs at the focal position due to dimensional errors, mounting errors, and the like.

  Therefore, there is a need for a reflector that can make maximum use of LED light.

  The light source device of the present invention is a light source device applicable to an apparatus that requires high light intensity, such as an exposure apparatus, and includes a plurality of LEDs and a rod-like support member in which the plurality of LEDs are arranged on the side surface in the axial direction. And a plurality of reflectors each having a reflection surface for guiding light from the corresponding LED in the axial direction and separately attached to the LED unit.

  For example, the reflecting surface of each reflector is configured to provide a partial ellipsoid formed by radially dividing the spheroid from the center. The mounting positions of the plurality of reflectors are adjusted so that the other focal positions of the reflecting surfaces coincide with each other.

  Or it is also possible to comprise the reflective surface of a reflector by the partial paraboloid formed by dividing | segmenting a rotating paraboloid radially from a center.

  In the present invention, the mounting positions of the reflectors are adjusted so that the focal positions of the reflecting surfaces coincide with the light emitting positions of the corresponding LEDs. As a result, light can be utilized to the maximum extent for all LEDs, and an LED light source device with high luminous efficiency can be provided.

  For example, the plurality of reflectors can be configured to be separated from each other by a predetermined distance along the circumferential direction of the support member.

  For example, it is possible to provide a cooling conduit for flowing a cooling liquid to the LED unit.

  Moreover, you may comprise so that several LED may be spaced apart along an axial direction. For example, the support member can be composed of a plurality of plate-like support portions having different side surface orientations, and the plurality of LEDs can be arranged on the side surfaces of the plurality of plate-like support portions.

  Alternatively, each reflector may be provided with a plurality of reflecting surfaces whose focal positions are light emitting positions of LEDs whose positions are different along the axial direction. Further, the reflective surface of each reflector may be determined by the material or the reflection wavelength characteristic according to the wavelength of light emitted from the corresponding LED.

  The plurality of LEDs include a first LED having a peak in a wavelength range of 365 nm to 436 nm, a second LED having a peak on a shorter wavelength side than the first LED in a wavelength range of 365 nm to 436 nm, and a wavelength range of 365 nm to 436 nm. Among these, at least two of the third LEDs having a peak on the shorter wavelength side than the second LED can be used.

  For example, the first LED has a peak near the g-line (436 nm), the second LED has a peak near the h-line (405 nm), and the third LED has a peak near the i-line (365 nm). .

  An exposure apparatus according to another aspect of the present invention includes a light source device having a plurality of LEDs, an optical system that guides light emitted from the plurality of LEDs to a photoreceptor formed on a surface of the drawing object, and the light source device. Light source control means for controlling the lighting of the light source, and exposure control means for performing an exposure operation on the exposure target area of the photoconductor.

  Examples of the exposure apparatus include a plurality of light modulation elements arranged two-dimensionally, a light modulation element array that guides illumination light from the light source to an exposure target area of a drawing object, and the exposure target area. Scanning means for moving relative to the object to be drawn, and the exposure control means controls the plurality of light modulation elements based on the pattern data corresponding to the position of the exposure target area.

  The plurality of LEDs of the present invention includes a first LED having a peak in a wavelength range of 365 nm to 436 nm, a second LED having a peak on a shorter wavelength side than the first LED in a wavelength range of 365 nm to 436 nm, and 365 nm to At least two of the third LEDs having a peak on the shorter wavelength side than the second LED in the wavelength region of 436 nm are included. For example, the first LED has a peak near the g-line (436 nm), the second LED has a peak near the h-line (405 nm), and the third LED has a peak near the i-line (365 nm). .

  Then, the light source control means determines the light emission order, the light emission intensity, the number of times of light emission, and the light emission time for at least two of the first, second, and third LEDs during the exposure operation period according to the sensitivity characteristic of the photoconductor. Adjust at least one of them.

  The photoconductor formed on the substrate surface has a different response to light depending on the difference in sensitivity characteristics. For example, in the case of a photoreceptor that reacts with light in the ultraviolet region to visible region such as g-rays, h-rays, and i-rays, which are specific to mercury lamps, the degree of light absorption and reaction speed differ depending on the spectrum.

  In order to obtain light in a wavelength range such as a mercury lamp using LEDs, it is necessary to turn on a plurality of LEDs that emit light in different wavelength ranges. However, if it is lit regardless of the sensitivity characteristics of the photoreceptor, it cannot be effectively exposed.

  Therefore, it is necessary to perform LED lighting control suitable for the sensitivity characteristic of the photoreceptor.

  In the exposure apparatus of the present invention, the light emission order and the like are adjusted according to the sensitivity characteristics, so that the exposure can be performed effectively.

  The light source control means can turn on the first LED before the second LED or the third LED during the exposure operation period.

  The light source control means can increase the light emission intensity of the first LED over the light emission intensity of the second LED or the third LED during the exposure operation period.

  Further, the light source control means causes the first LED, the second LED, and the third LED to emit light intermittently so that the number of times of light emission of the first LED is smaller than the number of times of light emission of the second LED or the third LED during the exposure operation period. You may do it.

  Alternatively, the light source control means may determine the number of the first LEDs that emit light during the exposure operation period to be equal to or less than the number of the second LEDs or the third LEDs that emit light.

  On the other hand, the light source control means can pulse the plurality of LEDs during the exposure operation period.

  Further, the light source control means may switch the light emission levels of the plurality of LEDs between an illumination period and a non-illumination period during the exposure operation period.

  According to the present invention, high illuminance can be achieved in an exposure apparatus using an LED light source device.

It is a schematic block diagram of the exposure apparatus which is this embodiment. It is a top view of a light source device. It is a side view of a light source device. It is the timing chart which showed LED lighting control at the time of exposure operation. It is a top view of the light source device used for the exposure apparatus which is 2nd Embodiment. It is a top view of the light source device used for the exposure apparatus which is 3rd Embodiment. It is a side view of the light source device which is 3rd Embodiment. It is a side view of the light source device used for the exposure apparatus which is 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic block diagram of an exposure apparatus according to this embodiment.

  The exposure apparatus 10 is a maskless exposure apparatus that directly forms a pattern on a substrate SW on which a photoconductor such as a photoresist is formed, and includes a light source device 20 and a DMD (Digital Micro-mirror Device) 22. Illumination light from the light source device 20 is applied to the substrate SW, and a pattern is formed on the photoreceptor applied or pasted on the surface of the substrate SW.

  The light source device 20 is a lighting device including a plurality of LEDs, and is driven by the LED driving unit 21. The light emitted from the light source device 20 is corrected to parallel light by the illumination optical system 25 and then guided to the DMD 22. The DMD 22 is a light modulation element array (here, 1024 × 1280) in which micro rectangular micromirrors of several μm to several tens μm are two-dimensionally arranged in a matrix, and is driven by the DMD driving circuit 24.

  Vector data such as CAD / CAM data transmitted from a workstation (not shown) is converted into raster data of a two-dimensional dot pattern by the raster conversion circuit 26. Then, the DMD drive circuit 24 transmits exposure data to the DMD 22 according to the raster data.

  In the DMD 22, each micromirror is selectively ON / OFF controlled based on the exposure data sent from the DMD drive circuit 24. The light reflected by the micromirror in the ON state passes through the projection optical system 27 and is applied to the substrate SW as light of a pattern image.

  The substrate SW is moved in the scanning direction by the stage driving mechanism 14. While the exposure target area relatively moves with the movement of the substrate SW, the exposure operation is executed at a predetermined exposure pitch. That is, pattern light is projected based on pattern data corresponding to the position of the exposure target area. A pattern is formed on the entire substrate by moving the exposure target area over the entire substrate SW. The position of the substrate SW is detected by the position detection sensor 15.

  The controller 28 outputs a control signal to the LED drive unit 21 and the like, and controls the entire exposure operation. A control program for the exposure operation is stored in a ROM (not shown) in the controller 28. As will be described later, the memory 29 stores a set of data relating to illumination according to the sensitivity characteristics of the photoreceptor.

  When information related to the photoconductor of the substrate SW is input by a user operating a keyboard (not shown), light emission control information corresponding to the photoconductor is read from the memory 29. The controller 28 outputs a control signal to the LED drive unit 21 based on the light emission control information.

  FIG. 2 is a plan view of the light source device. FIG. 3 is a side view of the light source device. The configuration of the light source device will be described with reference to FIGS.

  The light source device 20 is a water-cooled six-lamp type LED light source device, and includes a bowl-shaped reflecting portion 12 and a rod-shaped LED unit 30. The LED unit 30 includes a hexagonal columnar support member 32, and six LEDs 40 </ b> A to 40 </ b> F are disposed on each side surface of the support member 32. The light emitted radially from the LEDs 40 </ b> A to 40 </ b> F is guided in the emission direction along the axis C by the reflection unit 12. However, the axis C represents the central axis of the support member 32, that is, the central axis of the light source device. Moreover, in FIG. 3, the reflection part 12 is shown in the form divided | segmented along III-III of FIG.

  The support member 32 mounts a circuit board (not shown) such as a printed circuit board connected to the LEDs 40A to 40F, and is provided with a power supply circuit (not shown). One end of the support member 32 is attached to and held by one end of the cylindrical holder 34. Further, the reflecting portion 12 is also attached to the holder 34.

  A power supply terminal 37 is attached to the other end of the holder 34 and is electrically connected to the power supply circuit of the support member 32 through a lead wire (not shown). Power is supplied to the LED unit 30 by connecting the power supply terminal 37 of the support member 32 to a socket (not shown).

  Inside the support member 32, cooling pipes 35A and 35B for circulating a cooling liquid such as water are formed along the axial side surface, and the cooling liquid supplied from an external pipe (not shown) is supported. Circulate within member 32. While the LEDs 40A to 40F are lit, the generated heat is taken out by the coolant.

  The LEDs 40 </ b> A to 40 </ b> F have substantially the same radiation angle and are arranged in a line along the circumferential direction of the support member 32. Therefore, the positions of the LEDs 40A to 40F along the central axis C coincide with each other. Each LED is positioned at the center of the circumferential length on each side surface of the support member 32, and the LEDs 40A to 40F are symmetrically disposed when viewed from the direction of the axis C (see FIG. 3).

  The LEDs 40A to 40F emit light in the ultraviolet region to the visible region, each having a narrow wavelength region and strong directivity. The LEDs 40A and 40D emit light having a peak at g-line (436 nm) as bright lines, the LEDs 40B and 40E emit light at the peak at h-line (405 nm), and the LEDs 40C and 40F have i-line ( It emits light having a peak at 365 nm.

  The reflection unit 12 includes six reflectors 12 </ b> A to 12 </ b> F and is attached to the hexagonal column portion of the holder 34. The reflectors 12A to 12F are respectively provided with reflecting surfaces 12AR to 12FR on the inner surface facing the LED unit 30, and the reflecting surfaces 12AR to 12FR have a partial ellipsoidal shape. The reflecting surfaces 12AR to 12FR have at least reflection characteristics corresponding to the peak wavelengths of the LEDs 40A to 40F facing each other.

  Here, the partial ellipsoid represents a part of the ellipsoid formed by dividing the spheroidal ellipsoid divided in half between the two focal points into about six radially from the central axis. Therefore, each of the reflecting surfaces 12AR to 12FR has two focal points corresponding to the two focal points of the spheroid. One focal position of the reflecting surfaces 12AR to 12FR coincides with the light emitting position of the opposing LEDs 40A to 40F.

  The reflectors 12 </ b> A to 12 </ b> F are fixed to the side surface of the hexagonal columnar portion of the holder 34, and are attached slightly inward toward the central axis C. Thus, the other focal positions of the reflecting surfaces 12AR to 12FR all coincide with the point F on the central axis C. As a result, all the light emitted from the LEDs 40A to 40F at one focal position is collected at the point C which is the other focal position.

  The reflectors 12A to 12F are individually attached to the holder 34 by an adhesive or the like in order. At the time of attachment, the reflectors 12 </ b> A to 12 </ b> F are close to each other so that they are in contact with each other, and the reflectors 12 </ b> A to 12 </ b> F are also substantially symmetrically viewed from the central axis C.

  The mounting locations and mounting angles of the reflectors 12A to 12F are adjusted with high accuracy, for example, on the micro order level. Specifically, the illuminance, light intensity, and the like are measured while causing the corresponding LED to emit light, and the attachment position, angle, and the like are determined while confirming whether or not the light is condensed at the point F on the central axis C. The reflectors 12A to 12F are fixed to the holder 34 using an adhesive or the like.

  As described above, according to the present embodiment, the light source device 20 includes the LED unit 30 in which the LEDs 40A to 40F are arranged on the respective side surfaces of the support member 32, and the reflecting unit 12 including the reflectors 12A to 12F. The reflectors 12A to 12F are not integrally formed, and are individually mounted and adjusted along the side surfaces on which the LEDs 40A to 40F are arranged.

  There is a dimensional error between the LEDs 40A to 40F, and there is also a dimensional error in the support member 32 and the holder 34. However, since the reflectors 12A to 12F are individually mounted and adjusted, all the light from each LED is brought to one point. It can be condensed.

  FIG. 4 is a timing chart showing LED lighting control during the exposure operation.

  When the sensitivity characteristic of the photosensitive member is input by the user before the drawing process is started, data relating to LED lighting control corresponding to the sensitivity characteristic is read from the memory 29. Then, an exposure operation is executed at a predetermined exposure pitch. Here, the overlap exposure operation is performed at predetermined time intervals while the substrate SW is continuously relatively moved.

  FIG. 4 shows a lighting state of the LED when one exposure operation, that is, a pattern for one frame corresponding to the position of the exposure target area is projected. During the exposure operation period (one frame period), LED 40A that emits g-line light, LED 40B and LED 40E that emit h-line light, and LEDs 40C and 40F that emit i-line light are used. The LED 40D that emits g-line light is not used.

  As shown in FIG. 4, the LEDs 40A, 40B, 40C, 40E, and 40F are sequentially pulse-lit for each wavelength during the exposure period. Specifically, the g-line LED 40A that is on the relatively long wavelength side is first lit for a predetermined period T1, and then the h-line LEDs 40B and 40E are lit for a predetermined period T2. Finally, the i-line LED 40C on the short wavelength side is turned on for a predetermined period T3.

  This sequential lighting is repeated twice during one frame period. However, the g-line LED 40A is pulse-lit only once during one frame period. In addition, since the frame frequency is very high (for example, 10 kHz), the LEDs 40A, 40B, 40C, 40E, and 40F irradiate light to substantially the same exposure target area in one exposure operation.

  The pulse lighting of each LED does not switch the illumination ON / OFF, but switches between full lighting / half lighting. Light of intensity required for exposure is emitted by applying a pulse current in accordance with the full lighting period. On the other hand, during the non-illumination period, each LED emits light based on the steady current.

  The average current during a series of pulse lighting periods is equal to the rated current, and a steady current is flowing. This prevents a sudden inrush current from flowing to the LED in accordance with the amount of current during full lighting. Each LED has an excessive forward current characteristic. However, by supplying such a current, it is possible to cope with a case where the exposure operation time interval is very short, that is, the frame frequency is high. Pulse current generation for performing pulse lighting is performed by PWM control based on a predetermined duty ratio.

  The full lighting of the LEDs 40A to 40F differs for each wavelength with respect to the intensity and lighting time. The pulse current amount CG for the g-line LED 40A is larger than the current amount CH for the h-line LEDs 40B and 40E and the current amount CI for the i-line LEDs 40C and 40F. Therefore, the light intensity of the g-line LED 40A is higher than that of other LEDs. On the other hand, the full lighting time T1 of the g-line LED 40A is shorter than the full lighting time T2 of the h-line LEDs 40B and 40E and the full lighting time T3 of the i-line LEDs 40C and 40F.

  In this way, the LED 40A that emits light having a long wavelength is turned on first, and light having a long wavelength to a short wavelength is emitted in order, so that the light reaches the surface portion in order from the deep portion of the photoreceptor. The light is absorbed over the entire thickness direction of the photoreceptor. In addition, while increasing the emission intensity of the g-line LED 40A, the number of lighting, the full lighting time, and the number of lighting are less than those of the h-line and i-line LEDs, so that the g-line, h-line, and i-line light can be emitted. The exposure target area is uniformly irradiated.

  Note that the sequential lighting of the LEDs may not only be individually lit so as not to overlap each other, but also the lighting times may overlap each other. Further, the light intensity at the time of lighting, the lighting time, the number of lights, etc. can be set in accordance with the sensitivity characteristics of the photoconductor. Further, the pulse lighting may be switched on / off.

  In addition, the number of LEDs and reflectors and the shape of the support member can be appropriately selected according to the sensitivity characteristics of the photoconductor, and the LED can also be configured to emit light of two bright lines of the three bright lines. Further, it may be configured to emit light having a peak at another wavelength.

  If attention is paid to LED light emission control, an LED light source device based on a structure other than the above-described light source device can be applied, and an exposure device other than a maskless exposure device can also be applied. On the other hand, when focusing on the above-described LED lighting control, various structures can be applied to the structure of the LED unit and the reflector.

  Next, an exposure apparatus according to the second embodiment will be described with reference to FIG. In the second embodiment, the light source device used in the exposure apparatus is constituted by a four-lamp type LED unit having a reflector having a part of a rotating paraboloid as a reflecting surface. About another structure, it is the same as 1st Embodiment.

  FIG. 5 is a plan view of a light source device used in the exposure apparatus according to the second embodiment.

  The light source device 100 includes an LED unit 130 and a reflection unit 120 including four reflectors 120A to 120D. The LED unit 130 includes a square columnar support member 132, and four LEDs 140A to 140D are mounted on the side surfaces in the axial direction.

  The four reflectors 120A to 120D are individually attached to the side surfaces facing the LEDs 140A to 140D, respectively, and include reflection surfaces 120AR to 120DR. The reflecting surfaces 120AR to 120DR are partial paraboloids formed by dividing the rotating paraboloid radially from the central axis, and all the light emitted from the focal position of the rotating paraboloid is parallel light. Become.

  The reflectors 120A to 120D are mounted and adjusted so that the light emitting positions of the LEDs 140A to 140D coincide with the focal positions of the reflecting surfaces 120AR to 120DR. Further, the reflectors 120A to 120D are separated from each other by a predetermined distance M along the radial direction.

  As described above, the reflectors 120A to 120D are attached to the support member 132 with a predetermined interval M therebetween in advance, so that there is no possibility of coming into contact with an adjacent reflector during attachment adjustment. Therefore, the light from the LEDs 120A to 120D can be extracted to the maximum as parallel light.

  Next, an exposure apparatus according to the third embodiment will be described with reference to FIGS. In the third embodiment, the LEDs are spaced apart along the axial direction. About another structure, it is substantially the same as 1st Embodiment.

  FIG. 6 is a plan view of a light source device used in the exposure apparatus according to the third embodiment. FIG. 7 is a side view of the light source device according to the third embodiment.

  The light source device 200 includes an LED unit 230 in which four LEDs 240 </ b> A to 240 </ b> D are arranged, and a reflection unit 220 including reflectors 220 </ b> A to 220 </ b> D. The LED unit 230 includes a plate-like support portion 230A arranged on the emission side and a plate-like (strip-like) support portion 230B arranged behind the plate-like support portion 230A. The support portion 230B is joined in a crossed shape when viewed from the axial direction. Note that the holder is configured integrally with the support portion 230B.

  The LEDs 240A and 240C are disposed at positions facing each other with the plate-shaped support portion 230B interposed therebetween, and the LEDs 240B and 240D are disposed at positions facing each other with the plate-shaped support portion 230A interposed therebetween. As shown in FIG. 6, the lights of the LEDs 240 </ b> A, 240 </ b> C, 240 </ b> B, 240 </ b> D are radiated from different side surfaces of the support portions 230 </ b> A, 230 </ b> B as viewed from the axial direction.

  Each of the reflectors 220A to 220D includes reflection surfaces 220AR to 220DR which are partial ellipsoids formed by dividing the spheroid ellipse radially into four from the center. The reflectors 220A and 220C are attached and adjusted to the support portion 230B so that the focal positions of the reflecting surfaces 220AR and 220CR coincide with the light emission positions of the LEDs 240A and 240C. In FIG. 7, only the reflectors 220A and 220B are shown.

  On the other hand, the reflectors 220B and 220D are attached to the support portion 230B so that the focal positions of the reflecting surfaces 220AR and 220CR coincide with the light emission positions of the LEDs 240B and 240D. Therefore, the reflectors 220B and 220D extend to the emission side along the axial direction C with respect to the reflectors 220A and 220C.

  Furthermore, the reflectors 220A to 220D are mounted and adjusted so that the other focal positions of the reflecting surfaces 220AR to 220DR all coincide with the point FN on the axis. Thereby, all the light radiated | emitted from LED240A-240D is condensed by FN.

  With the structure of the support member in which two plate-like support parts are cross-joined, a large number of LEDs can be arranged while reducing the thickness, and all the light emitted from the LEDs can be condensed at one point. .

  Next, an exposure apparatus according to the fourth embodiment will be described with reference to FIG. In the fourth embodiment, a light source device is used in which each reflector includes a plurality of reflecting surfaces with different focal positions. Other configurations are substantially the same as those in the first embodiment.

  FIG. 8 is a side view of a light source device used in the exposure apparatus according to the fourth embodiment.

  The light source device 300 is a four-lamp type light source device including four LEDs 340A to 340D, and includes a reflective unit 320 including a quadrangular columnar LED unit 330 on which the LEDs 340A to 340D are installed, and semi-cylindrical reflectors 320A and 320B. With.

  The reflector 320A includes a rear reflector 320AS1 having a first reflecting surface 320AR1 formed on the inner surface and a front reflector 320AS2 having a second reflecting surface 320AR2 formed on the inner surface. The reflector 320B includes a rear reflector 320BS1 having a third reflecting surface 320BR1 formed on the inner surface and a front reflector 320BS2 having a fourth reflecting surface 320BR2 formed on the inner surface.

  The first reflecting surface 320AR1 and the third reflecting surface 320BR1 are partial ellipsoid surfaces formed by dividing one spheroid surface radially into two from the central axis. The second reflecting surface 320AR2 and the fourth reflecting surface 320BR2 are also partial ellipsoids formed by radially dividing one spheroid from the central axis.

  The rear reflector 320AS1 of the reflector 320A is attached to the square columnar LED unit 330, and the attachment position thereof is adjusted so that the focal position of the first reflecting surface 320AR1 coincides with the position of the LED 340D.

  On the other hand, the front reflector 320AS2 is attached to the opening side end of the rear reflector 320AS1, and the attachment position thereof is adjusted so that the focal position of the second reflecting surface 320AR2 matches the position of the LED 340A.

  Further, the rear reflector 320AS1 and the front reflector 320AS2 are mounted and adjusted so that the other focal positions of the first reflecting surface 320AR1 and the second reflecting surface 320AR2 coincide with the point FN on the central axis C.

  The attachment position of the reflector 320B is also adjusted in the same manner as the reflector 320A, and the light emitted from the LEDs 340B and 340C is collected at a point FN on the central axis C. Therefore, all the light emitted from the LEDs 340A to 340D is collected at the point FN.

  With such a configuration, it is possible to collect all the light from the LEDs while arranging the plurality of LEDs at different positions along the axial direction. If the LED unit 330 is a water-cooled unit, the diameter will inevitably increase when the number of LEDs is formed in accordance with the number of LEDs. It becomes possible to do.

  In the first to fourth embodiments, the reflecting surface of the reflector may be a spheroid or a paraboloid of revolution. Moreover, in addition to setting the reflection wavelength characteristics according to the peak wavelength of light emitted from the LED, the material of each reflecting surface can also be determined based on the wavelength range of the light emitted from the LED, It is possible to configure the reflecting portion by combining reflectors having different materials and reflection wavelength characteristics.

DESCRIPTION OF SYMBOLS 10 Exposure apparatus 12 Reflection part 12A-12F Reflector 20 Light source device 22 DMD
30 LED unit 40A-40F LED
32 Support member 34 Holder

Claims (21)

An LED unit having a plurality of LEDs and a rod-shaped support member in which the plurality of LEDs are arranged on the side surface in the axial direction;
A plurality of reflectors each having a reflective surface for guiding light from the corresponding LED in the axial direction and separately attached to the LED unit;
A light source device, wherein each reflector is mounted and adjusted so that a focal position of a reflecting surface coincides with a light emitting position of a corresponding LED.   The light source device according to claim 1, wherein the plurality of reflectors are separated from each other by a predetermined distance along a circumferential direction of the support member.   The light source device according to claim 1, wherein the LED unit has a cooling pipe through which a coolant flows.   The light source device according to claim 1, wherein the plurality of LEDs are spaced apart from each other along the axial direction. The support member has a plurality of plate-like support portions having different side surface directions,
The light source device according to claim 4, wherein the plurality of LEDs are arranged on a side surface of each of the plurality of plate-like support portions.   5. The light source device according to claim 4, wherein each reflector has a plurality of reflecting surfaces whose focal positions are light emitting positions of LEDs having different positions along the axial direction. The reflecting surface of each reflector has a partial ellipsoid formed by dividing the spheroid from the center radially,
The light source device according to any one of claims 1 to 6, wherein the plurality of reflectors are mounted and adjusted so that the other focal positions of the reflecting surfaces coincide with each other.   7. The light source device according to claim 1, wherein the reflecting surface of each reflector has a partial paraboloid formed by dividing a rotating paraboloid radially from the center.   The plurality of LEDs has a first LED having a peak in a wavelength range of 365 nm to 436 nm, a second LED having a peak on a shorter wavelength side than the first LED in a wavelength range of 365 nm to 436 nm, and a wavelength of 365 nm to 436 nm. 9. The light source device according to claim 1, comprising at least two of the third LEDs having a peak on a shorter wavelength side than the second LED in the region.   The first LED has a peak near the g-line (436 nm), the second LED has a peak near the h-line (405 nm), and the third LED has a peak near the i-line (365 nm). The light source device according to claim 9.   11. The light source device according to claim 1, wherein the reflective surface of each reflector has a material or a reflection wavelength characteristic determined according to a wavelength of light emitted from a corresponding LED. A light source device having a plurality of LEDs;
An optical system that guides light emitted from the plurality of LEDs to a photoreceptor formed on the surface of the drawing object;
Light source control means for controlling lighting of the light source device;
Exposure control means for performing an exposure operation on an exposure target area of the photoconductor,
The plurality of LEDs have a first LED having a peak in a wavelength range of 365 nm to 436 nm, a second LED having a peak on a shorter wavelength side than the first LED in a wavelength range of 365 nm to 436 nm, and a wavelength of 365 nm to 436 nm. Having at least two of the third LEDs having a peak on the shorter wavelength side than the second LED in the region,
The light source control means has at least one of a light emission sequence, light emission intensity, number of times of light emission, and light emission time for at least two of the first, second, and third LEDs during an exposure operation period according to sensitivity characteristics of the photoconductor. An exposure apparatus characterized by adjusting one of them.   13. The exposure apparatus according to claim 12, wherein the light source control means turns on the first LED before the second LED or the third LED during the exposure operation period.   13. The exposure apparatus according to claim 12, wherein the light source control means increases the light emission intensity of the first LED higher than the light emission intensity of the second LED or the third LED during an exposure operation period.   The light source control means causes the first LED, the second LED, and the third LED to emit light intermittently so that the number of times of light emission of the first LED is less than the number of times of light emission of the second LED or the third LED during the exposure operation period. The exposure apparatus according to claim 12.   13. The exposure apparatus according to claim 12, wherein the light source control means makes the light emission time of the first LED shorter than the light emission time of the second LED or the third LED during the exposure operation period.   13. The exposure apparatus according to claim 12, wherein the light source control means determines the number of the first LEDs that emit light during the exposure operation period to be equal to or less than the number of the second LEDs or the third LEDs that emit light.   18. The exposure apparatus according to claim 12, wherein the light source control means turns on the plurality of LEDs in pulses during an exposure operation period.   19. The exposure apparatus according to claim 18, wherein the light source control means switches the light emission levels of the plurality of LEDs between an illumination period and a non-illumination period during an exposure operation period.   The first LED has a peak near the g-line (436 nm), the second LED has a peak near the h-line (405 nm), and the third LED has a peak near the i-line (365 nm). The light source device according to claim 12, wherein: A plurality of light modulation elements arranged two-dimensionally, and a light modulation element array for guiding illumination light from the light source to an exposure target area of a drawing object;
Scanning means for moving the exposure target area relative to the object to be drawn;
21. The exposure apparatus according to claim 12, wherein the exposure control unit controls the plurality of light modulation elements based on pattern data corresponding to a position of an exposure target area.

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