JP2007234757A - Illumination optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system capable of accurately illuminating a long-sized wide region without lowering an illuminance. <P>SOLUTION: A sectional-area changing integrator changes the size of the cross section of a luminous flux projected onto a plane of an incidence while introducing the luminous flux onto an outgoing surface. A body to be irradiated arranged at a place approximately conjugate to the outgoing surface of the sectional-area changing integrator optically is illuminated by using the sectional-area changing integrator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illuminating device that illuminates a long region, and more particularly to an illuminating device that is preferable for exposure for manufacturing microdevices such as liquid crystal substrates for liquid crystal panels, printed wiring boards, semiconductor elements, image sensors, and thin film magnetic heads. .

A conventional illumination device for illuminating a long region uses a cylindrical lens (see, for example, Patent Document 1).
JP 2002-353090 A

  The conventional illumination device illuminates a long area using a cylindrical lens. When a cylindrical lens was used, at least two cylindrical lenses were required. For this reason, it is difficult to increase the area to be illuminated, and even if the area can be increased, the apparatus has to be expensive.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide an illumination optical system capable of accurately illuminating a long and wide area without reducing illuminance.

  In order to achieve the above object, in the present invention, the cross-sectional area is changed using a cross-sectional area changing integrator that changes the size of the cross section of the light beam incident on the incident surface and guides it to the exit surface. Illuminates an object to be irradiated that is arranged at a position that is optically conjugate with respect to the exit surface of the integrator.

Specifically, the illumination optical system according to the present invention is:
An illumination optical system for irradiating an irradiated body with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
A cross-sectional area change integrator having an incident surface on which a light beam guided from the condensing optical system is incident, and an exit surface that emits the light beam incident on the incident surface,
The cross-sectional area change integrator changes the size of the cross section of the light beam incident on the incident surface, and guides it to the exit surface.
The irradiated body is disposed at a position optically substantially conjugate with the exit surface of the cross-sectional area change integrator,
An illumination field is formed in the irradiated object by guiding a light beam emitted from the exit surface of the cross-sectional area changing integrator.

  An illumination optical system according to the present invention irradiates an irradiated body with a light beam emitted from a light source. This illumination optical system includes a condensing optical system and a cross-sectional area changing integrator. The condensing optical system condenses the light beam emitted from the light source. The cross-sectional area changing integrator has an entrance surface and an exit surface. The light beam guided from the condensing optical system is incident on the incident surface. From the exit surface, the light beam incident on the entrance surface is emitted. The cross-sectional area changing integrator changes the size of the cross section of the light beam incident on the incident surface. That is, as the light beam incident on the incident surface travels toward the exit surface, the size of the cross section of the light beam is changed. Here, the cross section is a cross section of the light beam in a plane substantially perpendicular to the traveling direction of the light beam. The traveling direction of the light beam may be a direction in which the entire light beam travels approximately in the cross-sectional area changing integrator. The light flux whose cross-sectional size has been changed is guided to the exit surface of the cross-sectional area change integrator and emitted.

  The irradiated body is disposed at a position optically conjugate with respect to the exit surface of the cross-sectional area changing integrator. By arranging in this way, it is possible to increase the illuminance and irradiate the irradiated body with the light flux.

  As described above, the cross-sectional area changing integrator changes the size of the cross section of the light beam incident on the incident surface. For this reason, the light beam can be irradiated by changing the cross section of the light beam so as to match the shape of the region to be illuminated of the irradiated object. In addition, since the light beam incident on the cross-sectional area changing integrator can be emitted, the light beam can be irradiated onto the irradiated object without reducing the illuminance.

The illumination optical system according to the present invention is
It is preferable that an area of the exit surface of the cross-sectional area change integrator is larger than an area of the incident surface of the cross-section area change integrator.

  Since the area of the exit surface of the cross-sectional area change integrator is larger than the area of the entrance surface, a wide area of the irradiated object can be irradiated.

The illumination optical system according to the present invention is
The cross-sectional area changing integrator extends a cross section of the light beam along a direction perpendicular to the optical axis of the cross-sectional area changing integrator as the light beam incident on the incident surface travels toward the exit surface. Those that are deformed or contracted are preferred.

  By doing in this way, according to the shape of the elongate area | region which should irradiate a to-be-irradiated body with a light beam, the shape of the cross section of the light beam to irradiate can be adapted.

The illumination optical system according to the present invention is
The entrance surface of the cross-sectional area change integrator and the exit surface of the cross-sectional area change integrator have a substantially rectangular shape,
The length of one opposing side of the entrance surface of the cross-sectional area change integrator and the length of one opposing side of the exit surface of the cross-sectional area change integrator are substantially the same,
The length of the other opposite side different from one opposite side of the exit surface of the cross-sectional area change integrator is longer than the length of another opposite side different from the one opposite side of the incident surface of the cross-sectional area change integrator Those are preferred.

  By doing in this way, according to the shape of the elongate area | region which should irradiate a to-be-irradiated body with a light beam, the shape of the cross section of the light beam to irradiate can be adapted. In addition, the length of one opposite side of the entrance surface of the cross-sectional area change integrator is substantially the same as the length of one opposite side of the exit surface, so that the structure of the cross-sectional area change integrator can be simplified, and the illumination optical system Can be made cheaper.

The illumination optical system according to the present invention is
A homogenizing integrator disposed between the condensing optical system and the cross-sectional area changing integrator,
The uniformizing integrator has an incident surface on which a light beam condensed by the condensing optical system is incident, and an exit surface on which the light beam incident on the incident surface of the uniformizing integrator is emitted, and the uniform integrator The illuminance of the light beam incident on the incident surface of the integrating integrator is made close to uniform and led to the exit surface of the uniformizing integrator,
The exit surface of the uniformizing integrator is preferably positioned so as to face the entrance surface of the cross-sectional area changing integrator.

  In this way, the light beam emitted from the homogenizing integrator can be incident on the cross-sectional area changing integrator, so that the illuminance can be made closer to uniform in advance by the homogenizing integrator, and the light beam whose illuminance has become more uniform. Can be irradiated to the irradiated object.

The illumination optical system according to the present invention is
Reflecting means disposed on the exit surface of the homogenizing integrator;
The reflecting means includes a passing portion that passes a part of the light beam emitted from the exit surface of the uniformizing integrator, and a reflecting portion that reflects the remaining light beam,
The passing portion of the reflecting means is positioned so as to face the incident surface of the cross-sectional area changing integrator,
The light beam that has passed through the passage part of the reflecting means is guided to the incident surface of the cross-sectional area change integrator,
It is preferable that the light beam reflected by the reflecting portion of the reflecting means reaches the vicinity of the light source via the incident surface of the homogenizing integrator and the condensing optical system.

  This makes it possible to irradiate the illuminated field of the irradiated object with a large luminous flux without changing the light source, such as increasing the output of the light source or increasing the light source. it can. In particular, when the illumination field of the irradiated object is not circular, for example, even when it is rectangular, the illuminance of the irradiated light beam can be increased without changing the light source.

The illumination optical system according to the present invention is
The light beam emitted from the cross-sectional area changing integrator is separated into a first polarized light beam having a first linearly polarized light component and a second polarized light beam having a second linearly polarized light component orthogonal to the first polarized light beam. A polarizing means for
It is preferable that the first polarized light beam is guided to the irradiated body and forms the illumination field of the irradiated body.

  This makes it possible to irradiate the illuminated field of the irradiated object with a large luminous flux without changing the light source, such as increasing the output of the light source or increasing the light source. it can.

  It is preferable that the “first polarized light beam” is a P-polarized light beam and the “second polarized light beam” is an S-polarized light beam.

  A long and wide area can be accurately illuminated without lowering the illuminance.

  Embodiments of the present invention will be described below with reference to the drawings.

<<<< first embodiment >>>>
FIG. 1 is a diagram showing an outline of a lighting device 10 according to a first embodiment of the present invention.
The lighting device 10 includes a lamp house 20, a rod 240, a rod 250, and a lens system 290. The lamp house 20 is mounted on the mounting table 50 and is arranged so that the light beam emitted from the light emitter 210 is irradiated onto the irradiated body 40.

  In FIG. 1, the optical path of one light beam among the light beams emitted from the light emitter 210 described later is shown. In FIG. 1, the lamp house 20 and the mounting table 50 are indicated by broken lines in order to clearly show the optical system. Furthermore, the to-be-irradiated body 40 shall be mounted in the support stand which is not shown in figure, and shall be located in the desired position.

<< light source >>
The light source is composed of a light emitter 210. As this illuminator 210, one that emits a light beam having a desired wavelength is used. For example, a lamp that emits ultraviolet rays having a short wavelength, such as a mercury lamp, can be used. In the bulb of the illuminant 210, mercury, which is a luminescent material, and two electrodes, an anode (not shown) and a cathode (not shown), are enclosed. The cathode and the anode are arranged to face each other. Each electrode is electrically connected to a metal conductor (not shown), and an arc discharge is formed between the cathode and the anode.

  One base 212a of the light emitter 210 is fixed to a support member (not shown) provided outside an elliptical mirror 220 described later. The other base 212b is connected to a power cable (not shown). The light emitter 210 is discharged by applying a predetermined voltage to both electrodes through these caps. Note that the power cable has a small diameter and does not hinder the luminous flux emitted from the light emitter 210.

  When arc discharge is generated between the anode and the cathode, strong light emission is generated from a discharge portion called an arc column. The luminous flux emitted from this arc column is divergent light spreading in all directions.

<< Condensing optical system >>
The condensing optical system condenses the light beam emitted from the light source. Specifically, the condensing optical system condenses the light beam emitted from the light emitter 210.

<Oval mirror 220>
The condensing optical system includes an elliptical mirror 220. As shown in FIG. 3, the elliptical mirror 220 has a reflective surface 222, and the elliptical mirror 220 is a reflective mirror whose shape of the reflective surface 222 is a spheroid. The elliptical mirror 220 has an open end 224 for emitting light. The contour along the edge of the open end 224 has a substantially circular shape. A through hole 226 is formed at the bottom of the elliptical mirror 220. A part of the light emitter 210 is disposed in the through hole 226. By arranging a part of the light emitter 210 in the through hole 226, the light emitter 210 can be positioned so that the arc portion of the light emitter 210 is located at the first focal point of the elliptical mirror 220, as will be described later. . The elliptical mirror 220 is arranged so that the open end 224 is at the top and the through hole 226 at the bottom is at the bottom. By arranging the elliptical mirror 220 in this way, the light beam emitted from the light emitter 210 can be reflected by the elliptical mirror 220 and guided to the upper part of the lamp house 20.

  As described above, the luminous flux emitted from the light emitter 210 is divergent light that spreads in all directions. Therefore, when the subject 40 is directly irradiated with the divergent light from the light emitter 210, the illumination on the object 40 is illuminated. Insufficient illuminance of luminous flux to irradiate the field. For this reason, the illuminance of the light beam applied to the illumination field on the irradiated body 40 can be increased by once collecting the light beam emitted from the light emitter 210. By doing in this way, the utilization efficiency of the light beam emitted from the light emitter 210 can be increased.

  As described above, in the illumination device according to the present invention, the elliptical mirror 220 is used for the condensing optical system. The elliptical mirror 220 has two focal points, a first focal point and a second focal point, and the illuminator 210 is supported so that the arc portion of the illuminant 210 is located at the first focal point of the elliptical mirror 220. It is supported by a member (not shown). In this way, the light beam emitted from the light emitter 210 is reflected by the reflecting surface 222 of the elliptical mirror 220 and collected at the second focal point.

<Reflection mirror 230>
The reflection mirror 230 is disposed above the elliptical mirror 220. The reflection mirror 230 is for changing the traveling direction of the light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220. The light beam emitted from the light emitter 210 is incident on the incident surface of an optical integrator described later. It is for guiding. Specifically, the reflecting mirror 230 changes the traveling direction so that the light beam reflected upward by the elliptical mirror 220 and directed upward is directed to the side of the lamp house 20 (right direction in FIG. 1 or FIG. 3). To do. Depending on the arrangement of the light emitter 210 and the optical integrator described later, the reflection mirror 230 may be omitted or the arrangement position and angle may be changed as appropriate.

<< Homogenization integrator >>
The homogenizing integrator has an entrance surface and an exit surface. The light beam collected by the condensing optical system is incident on the incident surface. The homogenizing integrator is for uniformly illuminating the illumination field formed on the irradiated object 40 by the light beam incident on the incident surface. A light flux for uniformly illuminating the illumination field formed on the irradiated body 40 is emitted from the exit surface of the uniformizing integrator. Any uniformizing integrator may be used as long as it can uniformly illuminate the illumination field with the light beam incident on the incident surface. Furthermore, even when the light emitter 210 as the light source has color unevenness or when the arc of the light emitter 210 has flicker, the color unevenness or flicker in the illumination field of the irradiated object 40 can be reduced.

  The homogenizing integrator includes, for example, a rod 240 as described later.

<Rod 240>
In this embodiment, the rod 240 is a glass rod having a substantially hexagonal columnar shape. As shown in FIG. 2, the rod 240 has an incident surface 242, an exit surface 244, and six side surfaces 248 a to 248 f.

  The entire light beam emitted from the light emitter 210 is incident on the incident surface 242 of the rod 240. For this reason, the shape of the light beam incident on the incident surface 242 of the rod 240 is substantially circular. For this reason, it is desirable to use a rod having a hexagonal cross-sectional shape in order to make the cross-sectional shape of the rod 240 nearly circular and to facilitate the manufacture of the rod 240. Energy loss can be reduced by using a hexagonal cross-section rod.

  The rod 240 exits from the exit surface 244 with the illuminance of the light beam incident from the entrance surface 242 made close to uniform. The light beam incident from the incident surface 242 is repeatedly reflected on the six side surfaces 248 a to 248 f inside the rod 240, and the angle components are mixed until the light beam reaches the emission surface 244 so that the illuminance is made closer to uniform. Further, the rod 240 can reduce uneven color and flicker.

  Furthermore, the rod 240 changes the cross-sectional shape of the light beam as the light beam travels in the rod 240. For example, in the case of a light beam emitted from the light emitter 210, the shape in a cross section perpendicular to the traveling direction of the light beam is substantially circular, and the light beam having this cross-sectional shape is incident on the incident surface 242 of the rod 240. Is done. When the cross section of the rod 240 is hexagonal, the light beam emitted from the exit surface 244 of the rod 240 has a substantially hexagonal cross section.

  In the present embodiment, a rod 240 having a substantially hexagonal columnar shape is used. However, any rod can be used as long as the illuminance can be made uniform and energy loss can be reduced. For example, a columnar body having a polygonal cross section such as a cylinder or a quadrangular column may be used.

  As shown in FIG. 1 or FIG. 3, the rod 240 is arranged so that the longitudinal direction is horizontal. Specifically, the rod 240 is arranged so that the incident surface 242 is located on the left side and the exit surface 244 is located on the right side. In this way, light incident on the incident surface 242 can be emitted in the horizontal direction from the emission surface 244.

  The rod 240 is disposed such that the light source image conjugate plane of the rod 240 is located at the optically second focal point of the elliptical mirror 220 or at a point conjugate with the second focal point. In the present embodiment, as described above, since the reflection mirror 230 is provided, the rod 240 has a light source image conjugate surface of the rod 240 optically through the reflection mirror 230 and optically connected to the first mirror of the elliptical mirror 220. It is arranged so as to be located at the second focal point or at a point conjugate with the second focal point.

  Note that a relay optical system (not shown) may be provided between the elliptical mirror 220 and the rod 240. In such a configuration, the position of the second focal point of the elliptical mirror 220 may be relayed to the illumination field conjugate plane of the rod 240 by the relay optical system. Furthermore, when focusing on the light source conjugate relationship, the relay optical system may be configured and arranged so that the light source conjugate surface becomes the incident surface of the rod 240.

  By arranging the rod 240 in this way, the light beam emitted from the light emitter 210 can be condensed on the light source image conjugate surface of the uniformizing integrator by the reflecting surface 222 of the elliptical mirror 220.

<< Reflecting means 246 >>
FIG. 2 is a diagram showing an example (a) of the rod 240 and an example (b) of the reflecting means 246 formed on the rod 240. 2A is a front view of the rod 240, and FIG. 2B is a right side view of the rod 240.

  As described above, the rod 240 has a substantially hexagonal columnar shape that is long along the traveling direction of the light beam, and the cross section perpendicular to the longitudinal direction is substantially composed of six side surfaces 248a to 248f. It has a hexagonal shape.

  The rod 240 has an incident surface 242 on which a light beam emitted from the light emitter 210 is incident, and an exit surface 244 from which a light beam whose illuminance is made close to uniform inside the rod 240 is emitted.

  As shown in FIG. 2B, the reflecting surface 246 is formed on the exit surface 244. The reflecting means 246 includes reflecting portions 246a and 246b and a passing portion 246c. In the example shown in FIG. 2B, the reflective portions 246a and 246b are indicated by hatching in order to clearly distinguish the reflective portions 246a and 246b from the passing portion 246c.

  As will be described later, the reflection portions 246a and 246b reflect the light beam emitted from the emission surface 244 and return it to the rod 240 again. The passage part 246c allows the light beam emitted from the emission surface 244 to pass through.

  The shape of the passage portion 246c is a flat hexagon, and is a shape determined so as to match the shape of the incident surface 252 of the rod 250 which is a cross-sectional area change integrator described later. When the shape of the incident surface 252 of the rod 250 is rectangular, it is most preferable that the shape of the passage portion 246c is also rectangular. However, in the first embodiment, the reflection means 246 is easily formed. Therefore, the shape of the passage portion 246c is a flat hexagon.

  The shapes of the reflection portions 246a and 246b are determined by the shape of the passage portion 246c. The material for forming the reflecting portions 246a and 246b may be any material that reflects the light beam, and in particular, a material that has a high reflectivity and is difficult to change the reflectivity due to heat. For example, the reflective portions 246a and 246b can be formed by evaporating a metal such as chrome or aluminum, particularly preferably a dielectric, on the exit surface 244. When a dielectric is used, heat generation can be suppressed by reducing absorption of light flux.

  The light beam that has passed through the passage portion 246c travels toward the rod 250 described later. On the other hand, the light beam reflected by the reflecting portion 246a or 246b passes through the rod 240 again and is emitted from the incident surface 242 toward the condensing optical system.

<The path of the light beam by the reflecting means 246>
Below, the path | route which the light beam emitted from the light-emitting body 210 follows is demonstrated using FIG. Note that the optical path shown in FIG. 3 shows one representative light beam out of the luminous flux emitted from the light emitter 210. As described above, the reflecting means 246 is formed on the exit surface 244 of the rod 240. In FIG. 3, the optical paths from the light emitter 210 to the reflecting portions 246a and 246b of the reflecting means 246 are indicated by solid lines P1 to P5, and the optical paths reflected by the reflecting portions 246a or 246b of the reflecting means 246 are returned. Indicated by broken lines R1 to R6.

  When this reflecting means 246 is used, the rod 240 is arranged so that the light source image conjugate surface of the rod 240 is optically positioned at the second focal point of the elliptical mirror 220. The rod 240 may be arranged so that the light source image conjugate surface of the rod 240 is optically located at a point conjugate with the second focal point of the elliptical mirror 220. In the present embodiment, as described above, since the reflection mirror 230 is provided, the rod 240 has a light source image conjugate surface of the rod 240 optically through the reflection mirror 230 and optically connected to the first mirror of the elliptical mirror 220. The two focal points are arranged.

  Note that a relay optical system (not shown) may be provided between the elliptical mirror 220 and the rod 240. In this case, the position of the second focal point of the elliptical mirror 220 may be relayed to the illumination field conjugate plane of the rod 240 by the relay optical system. Furthermore, when focusing on the light source conjugate relationship, the relay optical system may be configured and arranged so that the light source conjugate surface becomes the incident surface of the rod 240. Such a relay optical system converts the light beam collected by the reflection mirror 230 into a light beam suitable for entering the rod 240.

  First, the light beam emitted from the arc portion of the light emitter 210 reaches the reflecting surface 222 of the elliptical mirror 220 as indicated by the optical path P1. The light beam is reflected by the reflecting surface 222 and reaches the reflecting mirror 230 as indicated by the optical path P2. The light beam is reflected by the reflection mirror 230, reaches the incident surface 242 of the rod 240, and enters the rod 240 as indicated by the optical path P3. Inside the rod 240, as shown by optical paths P4 and P5, the light is uniformed while being reflected by the six side surfaces 248a to 248f and proceeds toward the exit surface 244 of the rod 240. The rod 240 is for uniformly illuminating the illumination field formed on the irradiated object 40 by the light flux that has entered the inside of the rod 240. Such a light beam is emitted from the passage portion 246 c of the reflecting means 246 formed on the emission surface 244 of the rod 240.

  On the exit surface 244 of the rod 240, the light beams S1 and S2 reaching the passage portion 246c pass and travel toward the rod 250 described later. On the other hand, the light flux that has reached the reflecting portion 246a or 246b is reflected by the reflecting portion 246a or 246b, and is reflected by the six side surfaces 248a to 248f toward the incident surface 242 of the rod 240 as shown by the optical paths R1 and R2. To advance inside the rod 240. The light beam reaching the incident surface 242 is emitted from the incident surface 242 and reaches the reflection mirror 230. The light beam is reflected by the reflecting mirror 230 and travels toward the reflecting surface 222 of the elliptical mirror 220 as indicated by the optical path R3. The light beam that has reached the reflecting surface 222 is reflected by the reflecting surface 222 and travels toward the arc portion (not shown) of the light emitter 210 as indicated by the optical path R4.

  The light beam that has reached the arc portion passes through the arc portion as shown by the optical path R4, travels toward the reflecting surface 222 to the elliptical mirror 220, and is reflected by the reflecting surface 222. As described above, since the arc portion of the light emitter 210 is the first focal point of the elliptical mirror 220, the light beam reflected by the reflecting surface 222 passes through the reflecting mirror 230 as shown in the optical paths R5 and R6. Then, it proceeds toward the light source image conjugate plane (not shown) of the rod 240, which is the second focal point of the elliptical mirror 220. That is, the light beam that has reached the arc portion travels toward the reflecting surface 222 of the elliptical mirror 220 as shown in the optical path R4, is reflected by the reflecting surface 222, and again enters the reflecting mirror 230 as shown in the optical path R5. Proceed toward. The light beam that has reached the reflection mirror 230 is reflected by the reflection mirror 230, travels toward the incident surface 242 of the rod 240, and enters the rod 240.

  In this way, the light beam reflected by the reflecting portions 246a and 246b of the reflecting means 246 passes through the incident surface 242 of the rod 240 and the elliptical mirror 220 that is a condensing optical system, and the arc of the light emitter 210 that is a light source. To the part. Further, thereafter, the light beam is again guided to the incident surface 242 of the rod 240 through the elliptical mirror 220 and travels inside the rod 240.

  As described above, the shape of the passage portion 246 c is a shape determined so as to match the shape of the incident surface of the rod 250. The light beams reflected by the reflecting portions 246a and 246b were originally light beams that did not reach the incident surface of the rod 250 in the absence of the reflecting portions 246a and 246b, and could not contribute to the incidence on the rod 250. Luminous flux. The light beam is reflected by the reflecting portions 246a and 246b, and returned to the rod 240 again to reach the rod 250. The light beam incident on the rod 250 without changing the output or number of the light emitters 210. The amount of illumination can be increased, and the illumination intensity of the illumination field formed on the irradiated object 40 can be increased.

<< Cross section change integrator >>
The cross-sectional area changing integrator has an entrance surface and an exit surface. A light beam emitted from a condensing optical system and passing through a rod 240 that is a uniformizing integrator is incident on the incident surface. The cross-sectional area change integrator changes the size of the cross section of the light beam incident on the incident surface and guides it to the exit surface. From the exit surface, the light beam guided from the entrance surface is emitted.

  The cross-sectional area changing integrator includes, for example, a rod 250 as described later.

<Rod 250>
FIG. 4 is a front view (a), a plan view (b), a left side view (c) and a right side view (d) showing the rod 250. The rod 250 has an incident surface 252, an exit surface 254, two side surfaces 256a and 256b, and two side surfaces 258a and 258b.

  As shown in FIG. 4C, the incident surface 252 has a substantially rectangular shape. The rod 250 is disposed so that the incident surface 252 is adjacent to the passage portion 246c of the reflecting means 246 formed on the exit surface 244 of the rod 240 described above (see FIG. 5). The rod 250 is preferably arranged so that the incident surface 252 of the rod 250 is in close contact with the passage portion 246c of the reflecting means 246 formed on the exit surface 244 of the rod 240.

  As shown in FIG. 4D, the emission surface 254 has a substantially rectangular shape. Further, as shown in FIGS. 4A and 4B, the exit surface 254 is formed to be substantially parallel to the entrance surface 252. The rod 250 is arranged so that the emission surface 254 is conjugate with the illumination field formed on the irradiated object 40.

  As shown in FIGS. 4C and 4D, the length of one opposite side 262a and 262b of the incident surface 252 and the length of one opposite side 264a and 264b of the emission surface 254 are substantially the same. In addition, the entrance surface 252 and the exit surface 254 are formed. Further, the length of the other opposite sides 264c and 264d different from the one opposite side 264a and 264b of the exit surface 254 is longer than the length of the other opposite sides 262c and 262d different from the one opposite side 262a and 262b of the incident surface 252. Also, the incident surface 252 and the exit surface 254 are formed so as to be longer.

  As shown in FIG. 4A, the two side surfaces 256a and 256b have a substantially rectangular shape. Further, as shown in FIG. 4B, the two side surfaces 256a and 256b are formed so as to face each other but not to be parallel to each other.

  As shown in FIG. 4B, the two side surfaces 258a and 258b have a substantially trapezoidal shape. As shown in FIG. 4C or 4D, the two side surfaces 258a and 258b are formed to be parallel to each other. Specifically, as shown in FIG. 4 (b), the two side surfaces 256a and 256b, and 2 so that the distance between the two side surfaces 256a and 256b gradually increases from the entrance surface 252 toward the exit surface 254. Two side surfaces 258a and 258b are formed.

  As shown in FIG. 4B, it is preferable that the two side surfaces 256a and 256b spread in a symmetric manner with respect to the optical axis T1. By forming the two side surfaces 256a and 256b so as to be symmetric with respect to the optical axis T1, the illuminance of the light beam passing through the rod 250 can be reduced so that the illuminance is not biased with respect to the optical axis T1. It can be kept uniform. Further, by increasing the distance between the two side surfaces 256a and 256b from the entrance surface 252 to the exit surface 254, the cross-sectional shape of the light beam passing through the rod 250 is perpendicular to the optical axis T1. Can be stretched along one direction X. In the present embodiment, this “one direction” is the direction of the line X shown in FIG. 3C or 3D, and is the longitudinal direction of the entrance surface 252 and the exit surface 254.

  As described above, the light beam can be extended by passing the light beam through the rod 250. The degree of this extension is determined by the ratio between the length of the opposite side 262c or 262d of the entrance surface 252 and the length of the opposite side 264c or 264d of the exit surface 254. Specifically, the expansion ratio is determined by the ratio between the length of the side 262c and the length of the side 264c, or the ratio between the length of the side 262d and the length of the side 264d. For example, when the length of the side 262c and the length of the side 264c is 2: 3, the expansion ratio is 3/2 times. That is, the light beam incident on the incident surface 252 is emitted from the exit surface 254 with its cross section expanded by 3/2 times in the X direction (see FIG. 4C or FIG. 4D). The expansion ratio may be determined according to the shape of the incident surface 252 of the rod 250 and the shape of the illumination field formed on the irradiated object 40. For example, the shape of the illumination field formed on the irradiated object 40 is a rectangle with a ratio of vertical to horizontal of 1: 4, and the shape of the incident surface 252 of the rod 250 has a ratio of vertical to horizontal of 1: 2. .7, 4 / 2.7≈3 / 2 can be obtained. That is, the ratio between the length of the side 262c and the length of the side 264c or the ratio between the length of the side 262d and the length of the side 264d can be set to 2: 3. In the above-described example, the case where the expansion rate is determined from the shape of the incident surface 252 of the rod 250 and the shape of the illumination field formed on the irradiated body 40 has been described. The shape of the incident surface 252 of the rod 250 may be determined from the shape of the illumination field formed on the rod.

  In the present embodiment, the lengths of the sides 262a and 262b of the incident surface 252 and the lengths of the sides 264a and 264b of the exit surface 254 are substantially the same, but the ratio of the sides is also different. You may do it. By doing in this way, the light beam suitable for the shape of the illumination field formed in the to-be-irradiated body 40 can be inject | emitted from the output surface 254. FIG.

  As described above, the rod 250 is disposed so that the incident surface 252 of the rod 250 is adjacent to the passage portion 246c of the reflecting means 246 formed on the exit surface 244 of the rod 240 described above. By arranging the rod 250 in the shape as described above and arranging in this manner, a light beam having a cross section extending in one direction (X direction) from the cross section of the light beam when entering the incident surface 252 is emitted. The surface 254 can be ejected. Since the light beam having a cross section extending in one direction (X direction) can be emitted from the emission surface 254 in this way, the NA (numerical aperture) can be increased, and the emission surface 254 can be obtained without reducing the illuminance. Can emit a luminous flux. Further, in the direction perpendicular to the one direction (X direction), the light beam exits from the exit surface 254 without expanding the cross section of the light beam, so that the illumination target 40 can be illuminated with a clear outline of the illumination field. it can. By doing in this way, the area | region of the elongate shape of the to-be-irradiated body 40 can be illuminated by making the outline of an illumination field clear, without reducing illumination intensity.

<< light guide means >>
<Lens system 290>
As shown in FIG. 1, a lens system 290 is arranged in the traveling direction of the light beam emitted from the exit surface 254 of the rod 250 described above. The lens system 290 includes at least one lens. In FIG. 1, only two lenses are shown as representative of the lens system 290. In FIG. 1, a reflection mirror 280 for changing the traveling direction of the light beam is also disposed. This lens system 290 is for enlarging and projecting the image of the exit surface 254 of the rod 250 onto the irradiated object 40. The lens system 290 is a relay lens, and converts the light beam in the vicinity of the irradiated body 40 so that the light beam becomes telecentric. The lens system 290 may be appropriately changed or omitted depending on the size of the illumination field formed on the irradiated object 40, the distance to the illumination field, and the like.

<< Outline of Lighting Device 10 >>
As described above, the rod 250 is formed so that the exit surface 254 is larger than the entrance surface 252 such that the distance between the two side surfaces 256a and 256b gradually increases from the entrance surface 252 toward the exit surface 254. Has been. By making the rod 250 in this way, the cross section of the light beam emitted from the exit surface 254 can be made to be a cross section extending in one direction from the cross section of the light beam when entering the entrance surface 252. Specifically, a light beam having an elliptical cross section can be emitted from the exit surface 254, and the entire shape of the light beam emitted from the exit surface 254 of the rod 250 is an elliptical cone or an elliptical truncated cone. Thus, the irradiated object 40 can be illuminated. For this reason, a rectangular-shaped illumination field or a long-shaped illumination field can be appropriately formed in the irradiated object 40. Furthermore, the outline of the illumination field can be clarified in a direction perpendicular to the one direction described above.

  Further, when the illumination field is formed in this way, all the light beams incident on the incident surface 252 can be emitted from the emission surface 254, and therefore, in one direction (X in FIG. 4C or FIG. 4D). NA (numerical aperture) can be increased with respect to (direction), the light beam can be emitted from the emission surface 254 without reducing the illuminance, and an illumination field can be formed on the irradiated object 40.

  Further, the reflection means 246 is formed on the exit surface 244 of the rod 240 described above. The reflection means 246 includes a passage portion 246c and reflection portions 246a and 246b. The passage part 246c passes a part of the light beam condensed by the condensing optical system. The light beam that has passed through the passage portion 246 c is incident on the incident surface 252 of the rod 250. On the other hand, the reflection portions 246a and 246b reflect the remaining light flux that could not pass through the passage portion 246c. The light beam reflected by the reflecting means reaches the vicinity of the illuminator 210 via a condensing optical system such as the elliptical mirror 220, and then goes again to the rod 240. By doing so, it is possible to increase the light flux that passes through the passage portion 246c of the reflecting means 246, so that the illuminance of the light flux incident on the rod 250 can be increased without changing the output or number of the light emitters 210. The illumination intensity of the illumination field formed on the irradiated object 40 can be increased.

<<< Second Embodiment >>>
FIG. 6 is a diagram showing an outline of the illumination device 100 according to the second embodiment of the present invention. In the diagram shown in FIG. 6, the same reference numerals are given to the same components as those in the first embodiment.

  In the second embodiment, a light source composed of a light emitter 210, a condensing optical system composed of an elliptical mirror 220, a rod 240 that is a homogenizing integrator, a rod 250 that is a cross-sectional area change integrator, and a lens system 290, , A prism 310, a λ / 4 wavelength plate 320, and a polarizing filter 330. The light source composed of the light emitter 210, the condensing optical system composed of the elliptical mirror 220, the rod 240 serving as the homogenizing integrator, the rod 250 serving as the cross-sectional area change integrator, and the lens system 290 are the first implementation. Since the configuration is the same as that of the embodiment, the description thereof is omitted.

<Prism 310>
The light beam emitted from the lens system 290 is incident on the prism 310. The prism 310 is for reflecting the light beam and guiding it obliquely downward.

<Λ / 4 wave plate 320>
The light beam guided by the prism 310 enters the λ / 4 wavelength plate 320. The λ / 4 wavelength plate 320 emits a light wave obtained by delaying the phase of the passing light beam by π / 2. In this embodiment, the λ / 4 wavelength plate 320 is used. However, the optical retarder is not limited to the λ / 4 wavelength plate 320, and an optical retarder that delays the phase of linearly polarized light in a predetermined direction by a desired angle ω can be used. .

<Polarizing filter 330>
The polarizing filter 330 transmits only the P-polarized light beam among the incident light beams, and reflects the S-polarized light beam. Here, P-polarized light refers to linearly polarized light whose light vibration plane is parallel to the incident surface, and S-polarized light refers to linearly polarized light whose light vibration surface is perpendicular to the incident surface. The P-polarized light beam corresponds to the “first polarized light beam”, and the S-polarized light beam corresponds to the “second polarized light beam”.

  The light beam that has passed through the polarizing filter 330 is emitted toward the irradiated object 40 and is irradiated on the irradiated object 40.

<Path of luminous flux>
The paths (P11 to P15) from the light beam emitted from the arc portion of the light emitter 210 to the prism 310 are the same as those of the illumination device 10 of the first embodiment.

  As shown in the optical path P15 in FIG. 6, the light beam emitted from the lens system 290 reaches the prism 310, and the light beam reflected by the prism 310 is converted into the λ / 4 wavelength plate 320 and the polarizing filter as shown in the optical path P16. The irradiated object 40 is irradiated through the line 330.

  The polarizing filter 330 transmits only the P-polarized light beam among the light beams incident on the polarizing filter 330 and reflects the S-polarized light beam. Therefore, only the P-polarized light beam is irradiated on the irradiated object 40. The S-polarized light beam reflected by the polarizing filter 330 enters the light absorber 340 and is absorbed inside the light absorber 340.

<< Outline of Lighting Device 100 >>
Also in the illumination device 100 of the second embodiment, the rod 250 is used. Therefore, the cross section of the light beam emitted from the exit surface 254 is a cross section extending in one direction (X direction in FIG. 4C or FIG. 4D) from the cross section of the light beam when incident on the incident surface 252. can do. Therefore, a rectangular-shaped illumination field or a long-shaped illumination field can be appropriately formed on the irradiated object 40. Furthermore, the outline of the illumination field can be clarified in the direction perpendicular to the one direction described above.

  Further, when the illumination field is formed in this way, all the light beams incident on the incident surface 252 can be emitted from the emission surface 254, and therefore, in one direction (X in FIG. 4C or FIG. 4D). NA (numerical aperture) can be increased with respect to (direction), the light beam can be emitted from the emission surface 254 without reducing the illuminance, and an illumination field can be formed on the irradiated object 40.

  Further, the reflection means 246 is formed on the exit surface 244 of the rod 240 described above. By this reflecting means 246, the remaining light flux that could not pass through the passage portion 246c is reflected. The light beam reflected by the reflecting means 246 reaches the vicinity of the light emitter 210 via a condensing optical system such as the elliptical mirror 220, and then travels toward the rod 240 again. By doing so, it is possible to increase the light flux that passes through the passage portion 246c of the reflecting means 246, so that the illuminance of the light flux incident on the rod 250 can be increased without changing the output or number of the light emitters 210. The illumination intensity of the illumination field formed on the irradiated object 40 can be increased.

  Further, in the second embodiment, the light beam collected by the condensing optical system is separated into a P-polarized light beam and an S-polarized light beam. The S-polarized light beam is a light beam of a component reflected by the polarization filter 330.

It is a figure which shows the outline | summary of the illuminating device 10 by 1st Embodiment. The front view (a) which shows the example of the rod 240, and the right view (b) which shows the example of the reflection means 246 formed in this rod 240. It is a figure which shows the optical path in the illuminating device 10 by 1st Embodiment. They are the front view (a) which shows the rod 250, a top view (b), a left view (c), and a right view (d). It is a perspective view which shows arrangement | positioning of the rod 240 and the rod 250. FIG. It is a figure which shows the outline | summary of the illuminating device 100 by 2nd Embodiment.

Explanation of symbols

10, 100 Illumination device 40 Subject to be irradiated 210 Light emitter (light source)
220 Elliptical mirror (condensing optical system)
240 Rod (Uniform integrator)
242 Entrance surface 244 Exit surface 246 Reflection means (reflection means)
246a and 246b Passing part 246c Reflecting part 250 Rod (cross-sectional area changing integrator)
252 entrance surface 254 exit surface 320 λ / 4 wave plate

Claims (7)

An illumination optical system for irradiating an irradiated body with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
A cross-sectional area change integrator having an incident surface on which a light beam guided from the condensing optical system is incident, and an exit surface that emits the light beam incident on the incident surface,
The cross-sectional area change integrator changes the size of the cross section of the light beam incident on the incident surface, and guides it to the exit surface.
The irradiated body is disposed at a position optically substantially conjugate with the exit surface of the cross-sectional area change integrator,
An illumination optical system, wherein an illumination field is formed on the irradiated body by guiding a light beam emitted from the exit surface of the cross-sectional area change integrator.   The illumination optical system according to claim 1, wherein an area of the exit surface of the cross-sectional area change integrator is larger than an area of the incident surface of the cross-section area change integrator.   The cross-sectional area changing integrator extends a cross section of the light beam along a direction perpendicular to the optical axis of the cross-sectional area changing integrator as the light beam incident on the incident surface travels toward the exit surface. The illumination optical system according to claim 1, wherein the illumination optical system is deformed or contracted. The entrance surface of the cross-sectional area change integrator and the exit surface of the cross-sectional area change integrator have a substantially rectangular shape,
The length of one opposing side of the entrance surface of the cross-sectional area change integrator and the length of one opposing side of the exit surface of the cross-sectional area change integrator are substantially the same,
The length of the other opposite side different from one opposite side of the exit surface of the cross-sectional area change integrator is longer than the length of another opposite side different from the one opposite side of the incident surface of the cross-sectional area change integrator The illumination optical system according to claim 1. A homogenizing integrator disposed between the condensing optical system and the cross-sectional area changing integrator,
The uniformizing integrator has an incident surface on which a light beam condensed by the condensing optical system is incident, and an exit surface on which the light beam incident on the incident surface of the uniformizing integrator is emitted, and the uniform integrator The illuminance of the light beam incident on the incident surface of the integrating integrator is made close to uniform and led to the exit surface of the uniformizing integrator,
The illumination optical system according to claim 1, wherein the exit surface of the uniformizing integrator is positioned so as to face the entrance surface of the cross-sectional area changing integrator. Reflecting means disposed on the exit surface of the homogenizing integrator;
The reflecting means includes a passing portion that passes a part of the light beam emitted from the exit surface of the uniformizing integrator, and a reflecting portion that reflects the remaining light beam,
The passing portion of the reflecting means is positioned so as to face the incident surface of the cross-sectional area changing integrator,
The light beam that has passed through the passage part of the reflecting means is guided to the incident surface of the cross-sectional area change integrator,
The illumination optical system according to claim 5, wherein the light beam reflected by the reflecting portion of the reflecting means reaches the vicinity of the light source via the incident surface of the uniformizing integrator and the condensing optical system. The light beam emitted from the cross-sectional area changing integrator is separated into a first polarized light beam having a first linearly polarized light component and a second polarized light beam having a second linearly polarized light component orthogonal to the first polarized light beam. A polarizing means for
The illumination optical system according to claim 1, wherein the first polarized light beam is guided to the irradiated body and forms the illumination field of the irradiated body.

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