JP2007005221A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system bringing illuminance of a central area of luminous flux close to that of areas other than the central area of the luminous flux, and preventing a void in an object to be irradiated. <P>SOLUTION: The object to be irradiated is illuminated by using an optical integrator where an incident surface of the optical integrator is formed slantly with respect to a plane vertical to the optical axis of the optical integrator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device that irradiates an irradiated object with uniform illuminance of a light beam emitted from a light source.

  Conventionally, discharge lamps such as xenon lamps and metal halide lamps have been often used as light sources used in lighting devices. In many cases, such a discharge lamp is arranged such that an electrode to which power is supplied is located on the optical path. For this reason, the luminous flux emitted from the light source is blocked by the electrodes, and the illuminance is distributed, making it difficult to illuminate the irradiated object with uniform illuminance.

  In order to prevent such illumination with uneven illuminance, there has been an attempt to make illuminance uniform by using a fly eye integrator (for example, see Patent Document 1).

  Some attempt to reduce the distribution of illuminance by setting the center position between the electrodes of the light source to a position shifted from the focal position of the reflecting mirror (see, for example, Patent Document 2).

  Furthermore, there has been an attempt to reduce the distribution of illuminance by shifting the position of the light source in the radial direction from the center of the reflecting mirror (see, for example, Patent Document 3).

Furthermore, there are some that attempt to reduce the illuminance distribution by disposing a concave cone lens between the reflecting mirror and the condensing point and dispersing the light beam reflected by the reflecting mirror toward the irradiated object. (For example, see Patent Document 4).
JP 2003-331622 A JP 2002-109909 A JP-A-11-232916 JP-A-8-248348

  All of the conventional illumination devices described above have been intended to reduce the distribution of illuminance, but in recent years, as an illumination device for an object to be irradiated, a device that further reduces the distribution of illuminance is desired. For example, a device that inspects scratches and dirt on a substrate such as a printed wiring board by image processing, and an illumination device that is used in a device that inspects the color tone of a color filter irradiates a light flux with a more uniform illuminance than before. There is a need to do that.

The present invention has been made in view of the above points, and an object of the present invention is to provide an illuminating device capable of illuminating an irradiated object with a luminous flux having a uniform illuminance while reducing the illuminance distribution. is there.
In order to achieve the above object, in the present invention, an object to be irradiated is used by using an optical integrator in which the incident surface of the optical integrator is inclined with respect to a plane perpendicular to the optical axis of the optical integrator. Illuminate.

Specifically, the lighting device according to the present invention is:
An illumination device that irradiates an irradiated object with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
An exit that emits a light beam for uniformly illuminating an incident surface on which the light beam condensed by the condensing optical system is incident and an illumination field formed on the irradiated object by the light beam incident on the incident surface. A light guiding optical system having at least one or more optical integrators,
The incident surface of the optical integrator is formed to be inclined with respect to a plane perpendicular to the optical axis of the optical integrator.

  An illumination device according to the present invention irradiates an irradiated object with a light beam emitted from a light source, and includes a condensing optical system and a light guiding optical system. In this specification, “light flux” refers to a collection of light beams emitted from a light source and reaching an irradiated object, or a bundle of light beams.

  The condensing optical system condenses the light beam emitted from the light source. The condensing optical system preferably guides the light beam emitted from the light source to the incident surface of an optical integrator described later. In particular, the condensing optical system is more preferably an elliptical mirror whose reflecting surface has a spheroid.

The light guide optical system has at least one or more optical integrators.
The optical integrator has an entrance surface and an exit surface. The light beam condensed by the condensing optical system is incident on the incident surface. The optical integrator is for illuminating an illumination field formed on an irradiated object by a light beam incident on an incident surface with an illuminance that is close to uniform. From the emission surface of the optical integrator, a light beam for illuminating an illumination field formed on the irradiated object with an illuminance that is made to be uniformly close is emitted.

  The optical integrator may be any optical integrator that attempts to make the illuminance of the light beam incident on the incident surface close to uniform. For example, it is preferable to use a rod as the optical integrator. The rod attempts to make the illuminance close to uniform by mixing the light beams incident on the incident surface of the rod by internally reflecting the light beams a plurality of times. By using this optical integrator, it is possible to emit a light beam with less uneven illuminance from the exit surface and irradiate the irradiated object with a light beam with nearly uniform illuminance.

  Further, the incident surface of the optical integrator is formed to be inclined with respect to a plane perpendicular to the optical axis of the optical integrator. Here, the optical axis of the optical integrator refers to a line connecting the center of the entrance surface of the optical integrator and the center of the exit surface of the optical integrator.

  By making the shape of the optical integrator like this, a part of the light beam incident on the incident surface of the optical integrator is refracted so that it travels toward the optical axis of the optical integrator at the incident surface of the optical integrator. Can be made. Here, the light beam refracted on the incident surface of the optical integrator does not need to be advanced only toward the optical axis, but may be advanced toward a region around the optical axis centering on the optical axis. The region around the optical axis is a region along the optical axis centering on the optical axis, and the distance from the optical axis along the plane perpendicular to the optical axis is the maximum distance of the optical integrator from the optical axis. A region included within 40% of the distance along the plane perpendicular to the optical axis to the outer periphery.

  In this way, a part of the light beam incident on the incident surface of the optical integrator is refracted so as to travel toward the area around the optical axis of the optical integrator at the incident surface of the optical integrator. The luminous flux passing through the area around the optical axis of the optical integrator can be increased, and the illuminance of the irradiated object area corresponding to the area around the optical axis of the optical integrator can be adjusted to the area other than the area around the optical axis. The illuminance in the area of the irradiated object can be brought close to, so that hollows in the irradiated object can be prevented.

  In particular, it is preferable that the normal line of the incident surface of the optical integrator is inclined with respect to a line connecting the position of the light source and the position where the light beam emitted from the light source is collected.

Furthermore, it is more preferable that the line connecting the position of the light source and the position where the light beam emitted from the light source is collected is aligned with the optical axis of the optical integrator. This facilitates adjustment of the optical axis of the light source, the condensing optical system, and the optical integrator, and the illuminance in the area around the optical axis of the optical integrator can be adjusted in the area other than the area around the optical axis. Illuminance can be approximated, and voids in the irradiated object can be prevented.
Furthermore, it is preferable that the optical integrator is a columnar rod except for the incident surface. A columnar shape is a cross-section along a plane perpendicular to the optical axis of the optical integrator, and has a constant cross-sectional shape up to the exit surface excluding the incident surface portion. Say. Specifically, the shape of the portion excluding the portion of the incident surface is preferably a cylindrical rod or a quadrangular rod, and most preferably a hexagonal rod. By using a hexagonal rod, the manufacturing of the rod can be facilitated, and since the shape is close to a circle, the cross-sectional shape of the light beam can be approximated, and other optical elements such as optical fibers can be used. A light beam can be emitted efficiently.

Further, the condensing optical system includes an elliptical mirror having a spheroidal reflecting surface, and
The light source is located near the first focal position of the elliptical mirror, and
It is preferable that the incident surface of the optical integrator is positioned in the vicinity of the second focal position of the elliptical mirror or in the vicinity of a position conjugate with the second focal position.

  The condensing optical system includes an elliptical mirror having a spheroidal reflecting surface, and has two focal points, a first focal point and a second focal point. A light source is positioned in the vicinity of the position of the first focus of the elliptical mirror. The vicinity of the position of the first focal point of the elliptical mirror means a range in which the light beam emitted from the light source can be condensed on the second focal point of the elliptical mirror. Specifically, it refers to a range where the distance from the position of the first focus is within ± 0.3 × f1. Here, f1 is the first focal length of the spheroid of the elliptical mirror. That is, f1 is the distance between the point where the major axis of the ellipsoid of the ellipsoidal mirror intersects the ellipsoid and close to the first focal point, and the first focal point. There are two points where the major axis of the spheroid of the elliptical mirror intersects the spheroid, one is a point close to the first focus (ie, a point far from the second focus), and the other is the first It is a point far from one focus (that is, a point close to the second focus).

  On the other hand, the incident surface of the optical integrator is positioned in the vicinity of the second focal position of the elliptical mirror. Alternatively, the incident surface of the optical integrator may be positioned in the vicinity of a position conjugate with the second focal position of the elliptical mirror. The vicinity of the second focal position of the elliptical mirror refers to a range in which the luminous flux collected by the elliptical mirror and the condensed luminous flux can be incident on the incident surface of the optical integrator. In addition, the vicinity of the position conjugate with the second focal position of the elliptical mirror means that the luminous flux collected by the elliptical mirror at a position conjugate with the second focal position of the elliptical mirror or the condensed luminous flux is incident on the incident surface of the optical integrator. The range that can be incident. Here, the “condensed light beam” refers to a light beam that has not reached the second focal position or a position conjugate with the second focal position and has not been condensed. In addition, the “condensed light beam” refers to a light beam that has reached the second focal position or a position conjugate with the second focal position, and that has converged once or has spread once.

  Thus, by positioning the light source, the condensing optical system, and the incident surface of the optical integrator, the light beam emitted from the light source can be efficiently and accurately supplied to the optical integrator, and the intensity of the light beam can be increased. The illumination object can be illuminated by reducing the illuminance of the light flux uniformly without reducing it.

The light guide optical system includes a concave cone lens having a concave surface formed in a conical shape,
The concave cone lens is arranged so that the optical axis of the concave cone lens and the optical axis of the optical integrator are aligned.
It is preferable that the concave cone lens is positioned in the vicinity of the second focal position or in the vicinity of a position conjugate with the second focal position.

  The light guide optical system described above includes a concave cone lens. This concave cone lens has a concave surface portion formed in a conical shape. The concave cone lens is arranged so that the optical axis of the concave cone lens and the optical axis of the optical integrator are aligned. The light beam emitted from the light source and condensed by the condensing optical system is incident on the incident surface of the concave cone lens. The light beam incident on the concave cone lens is emitted from the exit surface of the concave cone lens toward the entrance surface of the optical integrator. The concave cone lens is positioned in the vicinity of the second focal position. Alternatively, the concave cone lens may be positioned in the vicinity of a position conjugate with the second focal position.

  Here, the vicinity of the second focal position of the elliptical mirror refers to a range in which the light beam collected by the elliptical mirror can be emitted from the exit surface of the concave cone lens and incident on the incident surface of the optical integrator. . In addition, the vicinity of the conjugate position with the second focal position of the elliptical mirror means that the light beam collected by the elliptical mirror can be emitted from the exit surface of the concave cone lens and incident on the entrance surface of the optical integrator. A range.

  By arranging the concave cone lens in the vicinity of the second focal position of the elliptical mirror or in the vicinity of a position conjugate with the second focal position of the elliptical mirror, the illuminance of the light beam collected by the elliptical mirror is reduced to the concave surface. The concave surface portion of the cone lens can be brought closer to the uniform surface. By doing so, it is possible to make the luminous flux whose illuminance has been made to be uniform in advance on the incident surface of the optical integrator, so that the illuminance of the luminous flux emitted from the optical integrator can be made to be even more uniform, and the irradiated object Can be accurately prevented.

Moreover, the illumination device according to the present invention includes:
An illumination device that irradiates an irradiated object with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
An incident surface on which a light beam from the condensing optical system is incident; an exit surface that emits a light beam for uniformly illuminating an illumination field formed on the irradiated object by the light beam incident on the incident surface; A light guide optical system having at least one or more optical integrators,
The light guide optical system includes an incident surface on which a light beam collected by the condensing optical system is incident, an exit surface that emits the light beam incident on the incident surface toward the incident surface of the optical integrator, An optical element having
The incident surface of the optical element is formed to be inclined with respect to a plane perpendicular to the optical axis of the optical element.

  An illumination device according to the present invention irradiates an irradiated object with a light beam emitted from a light source, and includes a condensing optical system and a light guiding optical system. In this specification, the “light beam” refers to a collection of light beams emitted from a light source and reaching an irradiated object, or a bundle of light beams.

  The condensing optical system condenses the light beam emitted from the light source. The condensing optical system preferably guides the light beam emitted from the light source to the incident surface of the optical element of the light guide optical system described later. In particular, the condensing optical system is more preferably an elliptical mirror whose reflecting surface has a spheroid.

  The light guide optical system includes at least one optical integrator and an optical element.

  The optical integrator has an entrance surface and an exit surface. The light beam from the condensing optical system includes not only the case where the light beam is directly guided from the condensing optical system to the optical integrator, but also the case where the light beam is guided from the condensing optical system to the optical integrator via an optical element described later. . The optical integrator is for illuminating an illumination field formed on an irradiated object by a light beam incident on an incident surface with an illuminance that is close to uniform. From the emission surface of the optical integrator, a light beam for illuminating an illumination field formed on the irradiated object with an illuminance that is made to be uniformly close is emitted.

  The optical integrator may be any optical integrator that attempts to make the illuminance of the light beam incident on the incident surface close to uniform. For example, it is preferable to use a rod as the optical integrator. The rod attempts to make the illuminance close to uniform by mixing the light beam incident on the incident surface by reflecting the light beam a plurality of times inside. By using this optical integrator, it is possible to emit a light beam with less uneven illuminance from the exit surface and irradiate the irradiated object with a light beam with nearly uniform illuminance.

  The light guide optical system includes an optical element having an entrance surface and an exit surface. The light beam condensed by the condensing optical system is incident on the incident surface of the optical element. The incident surface of the optical element is inclined with respect to a plane perpendicular to the optical axis of the optical element. Here, the optical axis of the optical element refers to a line connecting the center of the entrance surface of the optical element and the center of the exit surface of the optical element. The light beam condensed by the condensing optical system is refracted at the incident surface of the optical element. The light beam refracted on the incident surface travels toward the exit surface of the optical element, and exits from the exit surface of the optical element toward the entrance surface of the optical integrator. The light beam emitted from the exit surface of the optical element enters the entrance surface of the optical integrator.

  By making the shape of the optical element like this and arranging the optical element and the optical integrator as described above, a part of the light flux incident on the incident surface of the optical element is changed to the optical element. Can be refracted at the incident surface of the optical element so as to approach the optical axis of the optical integrator or the optical axis of the optical integrator. It is preferable that the optical element is arranged so that the optical axis of the optical element coincides with the optical axis of the optical integrator.

  It is not necessary to advance toward the optical axis of the optical element or the optical axis of the optical integrator, but it is sufficient to advance toward the area around the optical axis centered on the optical axis of the optical element or the optical integrator. . The area around the optical axis of the optical element is an area around the optical axis, and the distance from the optical axis along the plane perpendicular to the optical axis is from the optical axis to the outermost periphery of the optical element. The region included within 40% of the distance along the plane perpendicular to the optical axis. The area around the optical axis of the optical integrator is an area centered on the optical axis, and the distance from the optical axis along the plane perpendicular to the optical axis is the maximum distance of the optical integrator from the optical axis. A region included within 40% of the distance along the plane perpendicular to the optical axis to the outer periphery.

  By making such a light beam enter the optical integrator, the light beam passing through the area around the optical axis of the optical integrator can be increased, and the illuminance in the area around the optical axis of the optical integrator It is possible to approach the illuminance of an area other than the area, and it is possible to prevent voids in the irradiated object.

  Furthermore, it is preferable that the exit surface of the optical integrator be formed in parallel to a surface perpendicular to the optical axis of the optical integrator. By doing so, it is possible to accurately irradiate the irradiated object from the exit surface of the optical integrator.

  By increasing the amount of light beam that passes through the optical integrator optical axis, the illumination intensity of the irradiated object area corresponding to the optical integrator optical area can be adjusted to areas other than the optical axis peripheral area. The illuminance of the irradiated object region can be brought close to, the illuminance of the light beam irradiated to the irradiated object can be made uniform, and hollows in the irradiated object can be prevented. Moreover, since the illuminance can be made uniform without using an extremely long optical integrator, the entire apparatus can be reduced in size. Furthermore, since the rod can be utilized, the illuminance can be made uniform without using additional optical elements, the configuration of the apparatus can be simplified, and the adjustment of the optical path can be facilitated.

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.

<< Configuration >>
The illumination device 10 includes a light source 20, a condensing optical system 22, and an optical integrator 24.

<Light source 20>
The light source 20 includes 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.

  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 22>
The condensing optical system 22 condenses the light beam emitted from the light source 20.

<Oval mirror 220>
The condensing optical system 22 includes an elliptical mirror 220. The elliptical mirror 220 has a reflecting surface 222, and the elliptical mirror 220 is a reflecting mirror having a shape of the reflecting surface 222 as a spheroid. As described above, the luminous flux emitted from the light emitter 210 is divergent light that spreads in all directions. Therefore, when the divergent light from the light emitter 210 is directly irradiated onto the irradiated object (not shown), the irradiated object The illuminance of the light beam illuminating the upper illumination field is insufficient. For this reason, the illuminance of the light beam applied to the illumination field of the irradiated object 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 F1 and a second focal point F2. The light emitter 210 is a support member (not shown) such that the arc portion of the light emitter 210 is located at the first focal point F1 of the elliptical mirror 220 or in the vicinity of the first focal point F1 of the elliptical mirror 220. ). By doing 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 F2. The vicinity of the first focal point F1 of the elliptical mirror 220 refers to a range in which the light beam emitted from the light emitter 210 and reflected by the reflecting surface 222 of the elliptical mirror 220 can be condensed on the second focal point F2. Specifically, the vicinity of the first focal point F1 of the elliptical mirror 220 means that the arc portion is located within a range within ± 0.3 × f1 from the position of the first focal point F1. Here, f1 is the first focal length of the spheroid of the elliptical mirror 220. That is, f1 is the distance between the first focal point F1 and the point near the first focal point F1 where the major axis of the ellipsoidal surface of the elliptical mirror 220 intersects the rotational ellipsoidal surface.

<Optical integrator 24>
The optical integrator 24 has an entrance surface and an exit surface. The light beam condensed by the condensing optical system 22 enters the incident surface. The optical integrator 24 is for illuminating the illumination field formed on the irradiated object by the light beam incident on the incident surface with the illuminance close to uniform. From the emission surface of the optical integrator 24, a light beam for illuminating an illumination field formed on the irradiated object with an illuminance that is made to be uniformly close is emitted. The optical integrator 24 may be anything that attempts to make the illuminance of the light beam incident on the incident surface uniform.

  The optical integrator 24 is disposed so that the incident surface of the optical integrator 24 is positioned at the second focal point of the elliptical mirror 220 or at a point conjugate with the second focal point.

  Further, when focusing on the light source conjugate relationship, when a rod described later is used, the relay optical system may be configured and arranged so that the light source conjugate surface becomes the incident surface of the rod. In the case of fly-eye, the relay optical system may be configured and arranged so that the light source conjugate surface becomes the fly-eye exit surface. By providing such a relay optical system, the light beam collected by the elliptical mirror 220 can be converted into an appropriate light beam and incident on the optical integrator 24.

  By arranging the optical integrator 24 in this way, the light beam emitted from the light emitter 210 can be condensed on the light source image conjugate surface of the optical integrator 24 by the reflecting surface 222 of the elliptical mirror 220.

  The optical integrator 24 is used to irradiate the illumination field of the irradiated object with light having a uniform illuminance. Furthermore, even when the light emitter 210 has color unevenness or when the arc of the light emitter 210 has flicker, color unevenness or flicker in the illumination field of the irradiated object can be reduced.

<Rod 240>
In the first embodiment, a rod 240 is used as the optical integrator 24. 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. In the present embodiment, rod 240 is made of an optically transparent material such as glass.

  The incident surface 242 of the rod 240 is formed to be inclined with respect to a surface perpendicular to the optical axis O2 of the rod 240. As shown in FIG. 1, the angle formed by the optical axis O2 of the rod 240 and the incident surface 242 of the rod 240 is α. The magnitude of α is preferably in the range of 45 degrees to 135 degrees. Furthermore, it is most desirable that the magnitude of α is 70 to 85 degrees or 95 to 110 degrees. Here, the optical axis O2 of the rod 240 refers to a line connecting the center of the incident surface 242 of the rod 240 and the center of the exit surface 244 of the rod 240.

  The rod 240 has a long shape along the optical axis O2 of the rod 240, and the cross section perpendicular to the optical axis O2 of the rod 240 is composed of six side surfaces except for a portion including the incident surface 242. Is a hexagon. As described above, the incident surface 242 of the rod 240 is formed to be inclined with respect to a surface perpendicular to the optical axis O2 of the rod 240. Therefore, the shape of the rod 240 excluding the part including the incident surface 242 has a hexagonal column shape. In this embodiment, a hexagonal rod is used for the cross section, but a circular or rectangular rod may be used.

  A light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 is incident on the incident surface 242 of the rod 240. On the incident surface 242 of the rod 240, the shape of the incident light beam is substantially circular. For this reason, in order to make the cross-sectional shape of the rod 240 close to a circle and to facilitate the manufacture of the rod 240, it is desirable to use a rod having a hexagonal cross-sectional shape as described above.

  The rod 240 mixes the angle components of the incident light beam inside, and the illuminance of the incident light beam is made close to uniform until reaching the exit surface 244 of the rod 240. From the exit surface of the rod 240, a light beam having an illuminance made uniform is emitted. The rod 240 can reduce uneven color and flicker.

  Further, the rod 240 converts the cross section of the light beam. 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 exit surface 244 of the rod 240 is rectangular, the cross-sectional shape of the light beam emitted from the exit surface 244 of the rod 240 is rectangular.

  That is, a rod 240 having an exit surface 244 that matches the shape of the illumination field of the irradiated object is used. For example, when the illumination field of the irradiated object is rectangular, a rod 240 having an emission surface 244 having a shape corresponding to the rectangle is used. For example, a rod 240 having an exit surface 244 that is similar to the shape of the illumination field of the irradiated object is used.

  As shown in FIG. 1, the rod 240 is arranged such that the optical axis O2 of the rod 240 is aligned with a line O1 connecting the arc portion of the light emitter 210 and the second focal point F2 of the elliptical mirror 220. Most preferably, 240 is arranged.

  Hereinafter, the light beam incident on the incident surface 242 of the rod 240 will be described with reference to FIG. Note that the optical path shown in FIG. 2 shows a representative one of the light beams incident on the incident surface 242 of the rod 240. The incident surface 242 of the rod 240 is disposed in the vicinity of the second focal point F <b> 2 of the elliptical mirror 220. This “near the second focus F2 of the elliptical mirror 220” will be described in detail later.

  As described above, the light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 is collected at the second focal point F2. The light beam once condensed at the second focal point F <b> 2 spreads again toward the incident surface 242 of the rod 240 and enters the incident surface 242 of the rod 240. In this embodiment, the rod 240 is made of glass, and the angle at which the light is refracted by the incident surface 242 is determined by the refractive index of the glass and the incident angle at which the light beam is incident on the incident surface 242.

  One light beam L <b> 1 of the light beam incident on the incident surface 242 of the rod 240 is refracted by the incident surface 242 and travels inside the rod 240. As shown in FIG. 2, the light beam L1 is refracted by the incident surface 242 and then travels away from the optical axis O2 of the rod 240 as shown by the light beam L1 '. Thereafter, after reaching the side surface of the rod 240, the light is reflected by the side surface of the rod 240 and proceeds toward the exit surface 244 while repeating reflection by the rod 240.

  The light beam L2 incident on the upper side of the incident surface 242 of the rod 240 and lower than the light beam L1 is also refracted by the incident surface 242 and travels inside the rod 240. As shown in FIG. 2, the light ray L2 is refracted by the incident surface 242 and then advances so as to approach the optical axis O2 of the rod 240 as shown by the light ray L2 '. Thus, by forming the incident surface 242 of the rod 240 to be inclined with respect to the surface perpendicular to the optical axis O2 of the rod 240, a part of the light beams incident on the incident surface 242 of the rod 240 is changed. , It can be refracted to approach the optical axis O2 of the rod 240 positively.

  In the above description, the case where the light beam refracted by the incident surface 242 of the rod 240 approaches the optical axis O2 is shown, but the refracted light beam not only approaches the optical axis O2 but also the light centered on the optical axis O2. It only needs to be close to the area around the axis O2. The area around the optical axis O2 is the area A2 shown in FIG. The area A2 around the optical axis O2 is an area along the optical axis O2 with the optical axis O2 as the center, and a distance from the optical axis O2 along a plane perpendicular to the optical axis O2 is a predetermined distance. It is an area included in the range below the distance. Further, the area A1 shown in FIG. 2 is the entire area of the rod 240, is an area along the optical axis O2 with the optical axis O2 as the center, and is along a plane perpendicular to the optical axis O2. The distance from the optical axis O <b> 2 is a region included in the range of the distance to the side surface of the rod 240. The predetermined distance of the region A2 described above refers to a distance of 40% of the distance from the optical axis O2 of the region A1 to the side surface of the rod 240. In this embodiment, since the rod 240 has a hexagonal cross section, the distance from the optical axis O2 along the plane perpendicular to the optical axis O2 is the radius of the circle inscribed in the hexagon. A region included within 40% is a region A2 around the optical axis O2.

  In this way, after the light beam is refracted by the incident surface 242 of the rod 240 and refracted, the light beam passing through the region A2 around the optical axis O2 of the rod 240 is made closer to the region A2 around the optical axis O2. Can be increased. By increasing the light flux passing through the region A2 around the optical axis O2 of the rod 240, the light flux reaching the region A2 on the exit surface 244 can also be increased as shown in FIG. The emitted light beam can be increased. By doing in this way, the illumination intensity of the area of the irradiated object corresponding to the area A2 around the optical axis O2 of the rod 240 is set to the area of the irradiated object corresponding to the area other than the area A2 around the optical axis O2. Since the illuminance can be made close and the illuminance of the light beam emitted from the exit surface 244 of the rod 240 can be made close to uniform, it is possible to prevent hollows in the irradiated object.

  As shown in FIG. 2, one light beam L <b> 3 or L <b> 4 of the light beam incident on the lower side of the incident surface 242 of the rod 240 is also refracted by the incident surface 242 and travels inside the rod 240. As shown in FIG. 2, the light beams L3 and L4 are refracted by the incident surface 242 and then travel away from the optical axis O2 of the rod 240 as shown by the light beams L3 'and L4'. Thereafter, after reaching the side surface of the rod 240, the light is reflected by the side surface of the rod 240 and proceeds toward the exit surface 244 while repeating reflection by the side surface of the rod 240.

  FIG. 3 is a diagram showing an outline when the incident surface 242 of the rod 240 is positioned in the vicinity of the position of the second focal point F <b> 2 of the elliptical mirror 220.

  As shown in FIG. 3, the light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 is condensed at the position of the second focal point F2. The light beams that travel most outward among the condensed light fluxes are denoted by LA1 and LA2, as shown in FIG.

  At the position of the second focal point F2, the shape of the collected light beam is substantially circular on a surface perpendicular to the optical axis O2 of the rod 240. Let W1 be the diameter of the light beam at the position of the second focal point F2. The effective diameter of the rod 240 is W2. In the present embodiment, as described above, since the rod 240 has a hexagonal cross section, the diameter of a circle inscribed in the hexagon is the effective diameter W2. Further, let x be the distance from the position of the second focus F2 to the center of the incident surface 242 of the rod 240 with the position of the second focus F2 as the origin. The positive direction of x is the + direction (right direction in the drawing) shown in FIG. 3, and the negative direction of x is the − direction (right direction in the drawing) shown in FIG. The case where x becomes negative is when the position of the center of the incident surface 242 of the rod 240 is located closer to the elliptical mirror 220 (left side of the drawing) than the position of the second focal point F2.

  The light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 is condensed at the position of the second focal point F <b> 2 and then spreads again toward the incident surface 242 of the rod 240. Among the light beams at this time, light beams traveling outward are denoted as LB1 and LB2. An angle between the light beam LB1 or LB2 and a line parallel to the optical axis O2 is β.

  As shown in FIG. 3, even when the incident surface 242 of the rod 240 is not disposed at the position of the second focal point F <b> 2 of the elliptical mirror 220, the light beam that spreads again from the second focal point F <b> 2 is incident on the rod 240. If the light can be incident on the surface 242, the light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 can be irradiated onto the irradiated object. In the present embodiment, the range in which the light beam emitted from the light emitter 210 and reflected by the elliptical mirror 220 can enter the incident surface 242 of the rod 240 is referred to as the vicinity of the position of the second focal point F2 of the elliptical mirror 220.

  That is, the vicinity of the position of the second focal point F2 of the elliptical mirror 220 means that the luminous flux condensed by the elliptical mirror 220 at the position of the second focal point F2 of the elliptical mirror 220 or the condensed luminous flux is incident on the incident surface 242 of the rod 240. The range that can be incident. Further, the vicinity of the position conjugate with the position of the second focal point F2 of the elliptical mirror 220 means that the luminous flux condensed by the elliptical mirror 220 to the position conjugate with the position of the second focal point F2 of the elliptical mirror 220 or the condensed luminous flux. The range in which the light can enter the incident surface 242 of the rod 240. Here, the “condensed light beam” refers to a light beam that has not reached the position of the second focal point F2 or a position conjugate with the position of the second focal point F2 and has not been condensed. The “condensed light beam” refers to a light beam that has reached the position of the second focal point F2 or a position conjugate with the position of the second focal point F2, and that has been once condensed and is spreading. .

  For example, in the case of the example shown in FIG. 3, a range in which the relationship | x | ≦ (W2−W1) / (2 × tan β) is established is referred to as a neighborhood. Here, | x | is the absolute value of x. As described above, x is the distance from the position of the second focal point F2 to the center of the incident surface 242 of the rod 240 with the position of the second focal point F2 as the origin, and may be a negative value. Further, tan is a tangent of a trigonometric function.

  Further, a range in which | x | ≦ (f1 + f2) / 2 is satisfied may be in the vicinity of the position of the second focal point F2 of the elliptical mirror 220. Here, f1 is the first focal length of the spheroid of the elliptical mirror 220. That is, f1 is the distance between the first focal point F1 and the point near the first focal point F1 where the major axis of the ellipsoidal surface of the elliptical mirror 220 intersects the rotational ellipsoidal surface. F2 is the second focal length of the spheroid of the elliptical mirror 220. That is, f2 is the distance between the first focal point F1 and the point where the major axis of the spheroid of the elliptical mirror 220 intersects the spheroid and is far from the first focal point F1.

  3 shows the case where the incident surface 242 of the rod 240 is positioned in the vicinity of the position of the second focal point F2 of the elliptical mirror 220, but the second focal point F2 of the elliptical mirror 220 is elliptical. If the position is conjugate with the second focus F2 of the mirror 220, the incident surface 242 of the rod 240 is the same as that positioned in the vicinity of the position conjugate with the second focus F2 of the elliptical mirror 220, and the relationship described above is obtained. The same holds true.

<< Action >>
By forming the incident surface 242 of the rod 240 to be inclined with respect to the surface perpendicular to the optical axis O2 of the rod 240, a part of the light beams incident on the incident surface 242 of the rod 240 is allowed to pass through the rod 240. The light can be refracted so as to approach the area A2 around the optical axis O2. By advancing such a light beam through the inside of the rod 240, the light beam passing through the area A2 around the optical axis O2 of the rod 240 can be increased. Thereby, the light flux reaching the region A2 on the exit surface 244 can also be increased, and the illuminance of the irradiated object region corresponding to the region A2 around the optical axis O2 of the rod 240 can be changed to the region A2 around the optical axis O2. Since the illuminance of the irradiated object region corresponding to the other region can be made close to that of the irradiated surface of the rod 240 and the illuminance of the light beam emitted from the exit surface 244 of the rod 240 can be made close to uniform, the void in the irradiated object is prevented. be able to.

  Further, since the illuminance of the light beam applied to the irradiated object can be made uniform without using an extremely long rod, the entire illumination device can be reduced. In addition, since the illuminance of the light flux can be made nearly uniform with only the rod, the illuminance can be made uniform without using additional optical elements, the configuration of the apparatus can be simplified, and the optical path can be easily adjusted. Can do.

<<< Second Embodiment >>>
FIG. 4 is a diagram showing an outline of the illumination device 12 according to the second embodiment of the present invention. Unlike the illumination device 10 according to the first embodiment, the illumination device 12 according to the second embodiment includes a concave cone lens 230. In FIG. 4, the same code | symbol was attached | subjected to the component which is common in the illuminating device 10 by 1st Embodiment.

<< Configuration >>
The illumination device 12 includes a light source 20, a condensing optical system 22, a concave cone lens 230, and an optical integrator 24.

<Light source 20>
The light source 20 includes a light emitter 210. The light source 20 has the same configuration as the illumination device 10 according to the first embodiment and has the same function.

<Condensing optical system 22>
The condensing optical system 22 condenses the light beam emitted from the light source 20.

<Oval mirror 220>
The condensing optical system 22 includes an elliptical mirror 220. In addition, this condensing optical system 22 is also the same structure as the illuminating device 10 by 1st Embodiment, and has the same function.

<Concave cone lens 230>
The concave cone lens 230 includes a flat surface portion 232 and a concave surface portion 234. The concave surface portion 234 is formed in a concave conical shape, so-called funnel shape or mortar shape. At the center of the concave surface portion 234, the bottom of the cone is formed.

  The flat surface portion 232 faces the elliptical mirror 220 and the concave surface portion 234 faces the incident surface of the rod 240. Further, the bottom of the concave surface portion 234 is positioned on the optical axis O <b> 2 of the rod 240. In particular, as shown in FIG. 4, it is desirable that the optical axis O5 of the concave cone lens 230 and the optical axis O2 of the rod 240 be arranged in a straight line. Here, the optical axis O5 of the concave cone lens 230 refers to a line connecting the center of the flat surface portion 232 and the center of the concave surface portion 234. The optical axis O2 of the rod 240 refers to a line connecting the center of the incident surface 242 of the rod 240 and the center of the exit surface 244 of the rod 240.

  By doing so, the light beam emitted from the light source 20 and reflected by the elliptical mirror 220 can be incident on the flat surface portion 232, and the light beam incident on the flat surface portion 232 can be emitted from the concave surface portion 234. it can.

  The concave cone lens 230 is disposed in the vicinity of the second focal point F2 of the elliptical mirror 220. Here, the vicinity of the position of the second focal point F2 of the elliptical mirror 220 means that a light beam emitted from the light source 20 and reflected by the elliptical mirror 220 is emitted from the concave surface portion 234 of the concave cone lens 230, and will be described later. The range in which the light can enter the incident surface 242 of the rod 240.

  Further, the concave cone lens 230 may be disposed in the vicinity of a position conjugate with the second focal point F2 of the elliptical mirror 220. Also in this case, the vicinity of the position conjugate with the second focal point F2 of the elliptical mirror 220 causes the light beam emitted from the light source 20 and reflected by the elliptical mirror 220 to be emitted from the concave surface portion 234 of the concave cone lens 230. Furthermore, it refers to a range in which the light can enter an incident surface 242 of the rod 240 described later.

  By disposing the concave cone lens 230 in this way, the light beam condensed by the elliptical mirror 220 can be further condensed by the concave cone lens 230. That is, the light beam condensed so as to be included in a certain range of area by the elliptical mirror 220 can be condensed by the concave cone lens 230 so as to be included in a narrower area. By doing so, the illuminance of the luminous flux can be made to approach uniformly uniformly in advance by the concave cone lens 230 before being incident on the incident surface 242 of the rod 240. By causing the light beam emitted from the concave cone lens 230 to enter the incident surface 242 of the rod 240, the illuminance of the light beam emitted from the rod 240 can be made more uniform, and the hollow in the irradiated object can be accurately detected. Can be prevented.

  In the example shown in FIG. 4, the case where the concave cone lens 230 is arranged so that the flat surface portion 232 faces the elliptical mirror 220 and the concave surface portion 234 faces the incident surface of the rod 240 is shown. The concave cone lens 230 may be arranged so that the concave surface portion 234 faces the elliptic mirror 220 and the concave surface portion 234 faces the incident surface of the rod 240. In this case, the light beam passing through the vicinity of the central portion of the concave cone lens 230 is emitted from the flat surface portion 232 so as to spread from the center. Since the light beam passing through the vicinity of the center part is emitted so as to spread from the center, the light beam with the illuminance near the center part uniformly approached can be emitted from the flat surface part 232, and is incident on the incident surface 242 of the rod 240 in advance. The light flux that has approached uniformly can be made incident, and the illuminance of the light flux emitted from the rod 240 can be made more uniform.

<Optical integrator 24>
Also in the second embodiment, the rod 240 is used as the optical integrator 24. The rod 240 has the same configuration as the lighting device 10 and has the same function. In the second embodiment, the rod 240 is condensed by the concave cone lens 230, and the light beam emitted from the concave surface portion 234 of the concave cone lens 230 is incident on the incident surface 242 of the rod 240. It suffices if they are arranged in such a manner.

  As described above, by making the light beam collected by the concave cone lens 230 incident on the incident surface 242 of the rod 240, the illuminance of the light beam emitted from the exit surface 244 of the rod 240 can be made more uniform. Therefore, it is possible to accurately prevent hollows in the irradiated object.

  Also in the second embodiment, as shown in FIG. 4, a line O1 connecting the arc portion of the light emitter 210 and the second focal point F2 of the elliptical mirror 220, the optical axis O5 of the concave cone lens 230, and the rod 240. It is most preferable to arrange the rod 240 so that the optical axis O2 is aligned with a straight line. As described above, the optical axis O5 of the concave cone lens 230 refers to a line connecting the center of the flat surface portion 232 and the center of the concave surface portion 234. The optical axis O2 of the rod 240 refers to a line connecting the center of the incident surface 242 of the rod 240 and the center of the exit surface 244 of the rod 240.

<<< Third Embodiment >>>
FIG. 5 is a diagram showing an outline of the illumination device 14 according to the third embodiment of the present invention. Unlike the illumination device 10 according to the first embodiment, the illumination device 14 according to the third embodiment includes an optical element 250 and a rod 260. In FIG. 5, the same reference numerals are given to components common to the illumination device 10 according to the first embodiment.

<< Configuration >>
The illumination device 14 includes a light source 20, a condensing optical system 22, an optical element 250, and an optical integrator 26.

<Light source 20>
The light source 20 includes a light emitter 210. The light source 20 has the same configuration as the illumination device 10 according to the first embodiment and has the same function.

<Condensing optical system 22>
The condensing optical system 22 condenses the light beam emitted from the light source 20.

<Oval mirror 220>
The condensing optical system 22 includes an elliptical mirror 220. In addition, this condensing optical system 22 is also the same structure as the illuminating device 10 by 1st Embodiment, and has the same function.

<Optical element 250>
The optical element 250 has a shape in which the rod 240 used in the first embodiment or the second embodiment described above is shortened in the direction of the optical axis O2. The optical element 250 has an entrance surface 252 and an exit surface 254. The incident surface 252 of the optical element 250 is formed to be inclined with respect to a plane perpendicular to the optical axis O3 of the optical element 250 and an optical axis O4 of a rod 260 described later. The optical axis O3 of the optical element 250 is a line connecting the center of the entrance surface 252 and the center of the exit surface 254. The optical element 250 is made of an optically transparent material such as glass.

  As shown in FIG. 5, the line O1 connecting the arc portion of the light emitter 210 and the second focal point F2 of the elliptical mirror 220, the optical axis O3 of the optical element 250, and the optical axis O4 of the rod 260 are straight. It is desirable that the optical element 250 and the rod 260 are arranged so as to be on a line.

  In the optical element 250, the incident surface 252 of the optical element 250 is arranged so that the light beam from the elliptical mirror 220 is incident thereon. In other words, the optical element 250 may be arranged so that the light beam emitted from the light source 20 and reflected by the elliptical mirror 220 is incident on the incident surface 252 of the optical element 250.

  Similar to the rod 240 shown in FIG. 2, the incident surface 252 of the optical element 250 is formed so as to be inclined with respect to the plane perpendicular to the optical axis O <b> 3 of the optical element 250, thereby entering the incident surface 252 of the optical element 250. A part of the emitted light beams can be positively refracted so as to approach the optical axis O3 of the optical element 250. By advancing such a light beam through the optical element 250, the light beam passing through the area A2 around the optical axis O3 of the optical element 250 can be increased. Here, similarly to the first embodiment, the area A2 around the optical axis O3 is a cross section perpendicular to the optical axis O3, and the distance from the optical axis O3 is the entire cross section of the optical element 250. An area included within 40% of the distance from the optical axis O3. In the present embodiment, since the optical element 250 has a hexagonal cross section, the region included within 40% of the radius of the circle inscribed in the hexagon is the region A2 around the optical axis O3. .

<Optical integrator 26>
The optical integrator 26 includes a rod 260. Unlike the first embodiment or the second embodiment, the rod 260 used in the third embodiment has a hexagonal prism shape. In other words, the incident surface 262 is formed in parallel with the surface perpendicular to the optical axis O4 of the rod 260, and is formed in parallel with the exit surface 264.

  The entrance surface 262 of the rod 260 is disposed so as to face the exit surface 254 of the optical element 250. The light beam emitted from the exit surface 254 of the optical element 250 enters the entrance surface 262 of the rod 260. The light beam refracted so as to approach the optical axis O3 of the optical element 250 at the incident surface 252 of the optical element 250 is not moved toward the optical axis O4 of the rod 240 even after entering the incident surface 262 of the rod 260. Go inside. Thus, by increasing the light flux that passes through the area A2 around the optical axis O4 of the rod 260, the light flux that reaches the area A2 on the exit surface 264 is also increased, as in FIG. 2 of the first embodiment. The illuminance of the irradiated object area corresponding to the area A2 around the optical axis O4 of the rod 260 is made closer to the illuminance of the irradiated object area corresponding to the area other than the area A2 around the optical axis O4. And can prevent voids in the irradiated object.

It is a figure which shows the outline | summary of the illuminating device 10 by 1st Embodiment. 4 is a schematic diagram showing a light beam incident on an incident surface 242 of a rod 240 and a light beam reaching an exit surface 244 of the rod 240. FIG. It is a figure which shows the outline when the incident surface 242 of the rod 240 is located in the vicinity of the position of the 2nd focus F2 of the elliptical mirror 220. FIG. It is a figure which shows the outline | summary of the illuminating device 12 by 2nd Embodiment. It is a figure which shows the outline | summary of the illuminating device 14 by 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 12, 14 Illuminating device 20 Light source 22 Condensing optical system 24 Optical integrator 26 Optical integrator 220 Elliptic mirror 230 Concave cone lens 240 Rod 250 Optical element 260 Rod

Claims (6)

An illumination device that irradiates an irradiated object with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
An exit that emits a light beam for uniformly illuminating an incident surface on which the light beam condensed by the condensing optical system is incident and an illumination field formed on the irradiated object by the light beam incident on the incident surface. A light guiding optical system having at least one or more optical integrators,
The illumination device according to claim 1, wherein the incident surface of the optical integrator is inclined with respect to a surface perpendicular to the optical axis of the optical integrator.   The illumination device according to claim 1, wherein a normal line of the incident surface of the optical integrator is inclined with respect to a line connecting a position of the light source and a position where a light beam emitted from the light source is collected. The condensing optical system includes an elliptical mirror having a spheroidal reflecting surface,
The light source is located near the first focal position of the elliptical mirror, and
The illuminating device according to claim 1, wherein the incident surface of the optical integrator is positioned in the vicinity of the second focal position of the elliptical mirror or in the vicinity of a position conjugate with the second focal position. The light guide optical system includes a concave cone lens having a concave surface formed in a conical shape,
The concave cone lens is arranged so that the optical axis of the concave cone lens and the optical axis of the optical integrator are aligned.
The illumination device according to claim 3, wherein the concave cone lens is positioned in the vicinity of the second focal position or in the vicinity of a position conjugate with the second focal position.   2. The illumination device according to claim 1, wherein a part of the light beam incident from the incident surface of the optical integrator is refracted so as to approach the optical axis of the optical integrator on the incident surface of the optical integrator. An illumination device that irradiates an irradiated object with a light beam emitted from a light source,
A condensing optical system for condensing a light beam emitted from the light source;
An incident surface on which a light beam from the condensing optical system is incident; an exit surface that emits a light beam for uniformly illuminating an illumination field formed on the irradiated object by the light beam incident on the incident surface; A light guide optical system having at least one or more optical integrators,
The light guide optical system includes an incident surface on which a light beam collected by the condensing optical system is incident, an exit surface that emits the light beam incident on the incident surface toward the incident surface of the optical integrator, An optical element having
The illumination device according to claim 1, wherein the incident surface of the optical element is inclined with respect to a plane perpendicular to the optical axis of the optical element.

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