JP2005195348A - Illumination optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical apparatus, capable of correctly monitoring luminous quantities at a surface to be irradiated without having to strictly adjust the positions of an illumination optical system and a photo-detector. <P>SOLUTION: The illumination optical apparatus is provided with generation means 11, 12, 15, and 16 for generating optical images of which the luminous quantity distributions are made uniform; projection means 17 and 18 for projecting the optical images to the surface 10a to be irradiated conjugate with an optical image surface; and a monitoring means 20 for monitoring the luminous quantities of the optical images projected to the surface to be irradiated. The generation means includes an integrator rod 16, and a light emergent surface 16b of the integrator rod is arranged in a surface conjugate with the surface to be irradiated. The monitoring means has a light branching surface 21 for branching part of light, propagating toward the light emergent surface in the integrator rod, in the vicinity of the light emergent surface in directions different from the light emergent surface and monitors luminous quantities at the surface to be irradiated on the basis of light L1 branched at the light branching surface and guided to the outside of the integrator rod. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illumination optical apparatus that uniformly illuminates an irradiated surface, and more particularly to an illumination optical apparatus suitable for imaging element inspection in an imaging element manufacturing process.

Devices that use an optical integrator such as an integrator rod or fly-eye lens to uniformly illuminate a relatively wide area on an irradiated surface are known.
Conventionally, the light amount monitor of this type of illumination device has been provided with a half mirror on the illumination field side of the condenser lens to extract a predetermined proportion of light and monitor the light amount. However, if the half mirror is arranged on the illumination field side of the condenser lens, the space between the illumination device and the illumination field cannot be increased, and the pupil is placed in this space according to the type of the object to be inspected (for example, the image sensor). It was necessary to insert a conversion adapter for changing the position, and there was a problem that the degree of freedom for arranging the half mirrors was lost.

If a half mirror is arranged on the light source side of the condenser lens, the illumination light beam spreads from the aperture when the illumination range is wide, so the angle of light incident on the half mirror changes depending on the illumination position, and the angle of the half mirror There is a problem that a change in the illumination light quantity and the spectral characteristic of the illumination light depending on the illumination position is caused by the influence of the characteristics.
On the other hand, as in the patent document described below, there is one that takes in a part of light emitted from an optical integrator in order to monitor the amount of light on the irradiated surface. An optical fiber is used for capturing light, and light guided by the optical fiber is monitored by a photodetector placed at the exit end of the optical fiber. Based on the output from the photodetector, the amount of light on the irradiated surface is monitored.
JP 2001-307523 A

  However, when an optical fiber is used as a light guide, the light transmitted through the exit surface of the light quantity uniformizing means (optical integrator) is uniformed, but if the light distribution characteristics change due to lamp replacement, etc., The emission angle characteristic of the light quantity uniformizing means changes according to the change in the orientation characteristic of the light incident on the light quantity uniformizing means. The light incident on the end face of the optical fiber has different coupling efficiency with the fiber depending on the incident angle, and the amount of guided light changes. Accordingly, the amount of light detected by the photodetector changes due to the change in the emission angle characteristic from the light amount equalizing means, and the amount of light on the irradiated surface cannot be monitored correctly.

In addition, when light is guided to a photodetector at a predetermined position while deforming the optical fiber, the attenuation factor of the guided light changes due to the difference in the deformed shape. If the deformation shape or curvature of the optical fiber changes, the amount of light on the irradiated surface cannot be monitored correctly.
SUMMARY OF THE INVENTION An object of the present invention is to provide an illumination optical device that can correctly monitor the amount of light on an irradiated surface without strict position adjustment between an illumination optical system and a photodetector.

  The illumination optical apparatus according to claim 1, a generation unit that generates a light image with a uniform light amount distribution, a projection unit that projects the light image onto an irradiated surface conjugate with the light image surface, and the target Monitoring means for monitoring the amount of light of the light image projected on the irradiated surface, the generating means includes an integrator rod, and the light emitting surface of the integrator rod is disposed on a surface conjugate with the irradiated surface. The monitoring means has a light branching surface that branches a part of the light propagating in the integrator rod toward the light emitting surface in a direction different from the light emitting surface in the vicinity of the light emitting surface, The light quantity is monitored based on the light branched off at the light branching surface and guided to the outside of the integrator rod.

According to a second aspect of the present invention, in the illumination optical device according to the first aspect, the light branching surface is provided so as to cross the integrator rod obliquely.
The illumination optical apparatus according to claim 3 includes a generation unit that generates a light image with a uniform light amount distribution, a projection unit that projects the light image onto an irradiated surface conjugate with the light image surface, and the target Monitoring means for monitoring the amount of light of the optical image projected on the irradiation surface, the projection means including a fly-eye lens comprising a plurality of lens elements arranged two-dimensionally, and the pupil plane of the projection means Arranged on a plane conjugate with the light exit surface of the eye lens, the monitoring means transmits light propagating toward the light exit surface through at least one of the lens elements disposed at the four corners of the fly-eye lens. A light reflecting surface that reflects in a direction different from the light emitting surface is provided, and the light amount is monitored based on light reflected by the light reflecting surface and guided to the outside of the fly-eye lens.

According to a fourth aspect of the present invention, in the illumination optical device according to the third aspect, the light reflecting surface is provided so as to obliquely cross the lens element.
The illumination optical apparatus according to claim 5 includes a generation unit that generates a light image with a uniform light amount distribution, a projection unit that projects the light image onto an irradiated surface conjugate with the light image surface, and the target A monitoring unit that monitors the amount of light of the light image projected on the irradiation surface; and an aperture stop disposed on the light exit surface of the generation unit or the pupil plane of the projection unit. The light quantity is monitored based on the blocked light.

  The illumination optical apparatus according to claim 6 includes a generation unit that generates a light image with a uniform light amount distribution, a projection unit that projects the light image onto an irradiated surface conjugate with the light image surface, and the target Monitoring means for monitoring the amount of light of the light image projected on the irradiation surface, the monitoring means has a light branching surface disposed in the vicinity of the light image surface, and the light branched at the light branching surface. Based on this, the light quantity is monitored.

  The illumination optical device according to claim 7 includes a projecting unit that projects a light image with a uniform light amount distribution onto the irradiated surface, and a monitoring unit that monitors the light amount of the light image projected onto the irradiated surface. The projection unit includes a fly-eye lens including a plurality of two-dimensionally arranged lens elements, and a pupil plane of the projection unit is disposed on a plane conjugate with a light emitting surface of the fly-eye lens, and the monitoring unit Has a light reflecting surface for reflecting light propagating toward the light emitting surface in at least one of the lens elements arranged at the four corners of the fly-eye lens in a direction different from the light emitting surface, The light quantity is monitored based on light reflected by the light reflecting surface and guided to the outside of the fly-eye lens.

  According to the illumination optical apparatus of the present invention, it is possible to correctly monitor the amount of light on the irradiated surface without performing precise position adjustment between the illumination optical system and the photodetector.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
In this example, the illumination optical device 10 (FIG. 1) of the first embodiment is incorporated in an apparatus for inspecting an image sensor in a wafer state before being cut out from the wafer in a manufacturing process of an image sensor such as a CCD or a CMOS. Give an explanation. The inspection of the image sensor is an inspection of the presence / absence of a pixel defect, sensitivity to light, color reproducibility, spectral characteristics, and the like. As shown in FIG. 1, the apparatus for performing such inspection includes a probe 31 and a signal processing device 32 in addition to the illumination optical device 10. The probe 31 is an electrical terminal that can contact an electrode of a circuit of the image sensor. The signal processing device 32 supplies power to the image sensor and transmits / receives signals to / from the image sensor via the probe 31, and determines whether the output signal of the image sensor is appropriate (that is, whether the image sensor is good or bad). It is.

  The illumination optical device 10 according to the first embodiment will be described. The illumination optical device 10 sets illumination conditions for inspecting the image sensor, and uses a light with the set illumination conditions, so that a relatively wide range of the irradiated surface 10a (a range wider than the imaging area of the image sensor). Is a device that uniformly illuminates the light. The illumination optical device 10 includes a light source 11, a collector lens 12, a density filter 13, a filter group 14, an input lens 15, an integrator rod 16, a fly-eye lens 17, a condenser lens 18, and a pupil position conversion adapter. 19 and a light amount monitor 20.

  Among these, the components related to the setting of illumination conditions when inspecting the image sensor are the density filter 13, the filter group 14, and the pupil position conversion adapter 19. The density filter 13 is rotatably mounted by a motor 13a and intersects the optical axis 10b of the illumination optical device 10 at a position different from the rotation center 13b. The density filter 13 is provided with a density gradient such that the optical density changes, for example, in the circumferential direction within the C-shaped region 13c shown in FIG. The light amount (illuminance) on the irradiated surface 10a can be adjusted by the rotation of the density filter 13.

  The filter group 14 includes a color filter, a color temperature conversion filter, and the like, and can be switched according to inspection contents by a mechanism (not shown). By switching the filter group 14, the spectral spectrum on the irradiated surface 10a can be adjusted. The pupil position conversion adapter 19 is obtained by attaching a diaphragm plate 26 to a diffusion plate 25. The diaphragm plate 26 has a predetermined opening diameter. By disposing the pupil position conversion adapter 19 on the optical axis 10b, diffused light having a predetermined incident angle range can be incident on the irradiated surface 10a (diffuse illumination).

  In the illumination optical device 10 of the first embodiment, the light emitted from the light source 11 is collected by the collector lens 12, becomes substantially parallel light, passes through the density filter 13 and the filter group 14, and is integrated by the input lens 15. The light is collected on the light incident surface 16 a of the rod 16. An image of the light source 11 is formed on the light incident surface 16 a of the integrator rod 16. The integrator rod 16 is made of a rod-shaped glass material (whose cross section is rectangular), and is also called a rod lens or a rod-type optical integrator. The light emitting surface 16 b of the integrator rod 16 is disposed on a surface conjugate with the irradiated surface 10 a of the illumination optical device 10.

  Inside the integrator rod 16, the light incident from the light incident surface 16a repeats internal reflection (that is, total reflection at the side surface 16c) by the number of times corresponding to the incident angle, and propagates toward the light emitting surface 16b. Then, on the light exit surface 16b, light having different reflection times overlaps, and the light amount distribution is made uniform. That is, the light source 11, the collector lens 12, the input lens 15, and the integrator rod 16 generate an optical image with a uniform light amount distribution in the light exit surface 16b (that is, a surface conjugate to the irradiated surface 10a). Can do.

  By the way, in the illumination optical apparatus 10 of 1st Embodiment, the light branch surface 21 which crosses the integrator rod 16 at 45 degree | times diagonally in the vicinity of the light-projection surface 16b of the integrator rod 16 is provided. The light branching surface 21 is a plane on which a half mirror coat is applied, and has a reflectance of 2% to 5%, for example. For example, as shown in FIG. 3, the integrator rod 16 having the light branching surface 21 includes a glass member 23 having a shape in which one end side of a rectangular parallelepiped is cut out at an angle of 45 degrees and a glass member 24 having a right-angle prism shape. A half mirror coat is applied to the slope 23a of the glass member 23 or the slope 24a of the glass member 24, and then bonded using an adhesive having the same refractive index as that of the glass material.

  Accordingly, a part of the light propagating in the integrator rod 16 toward the light exit surface 16b (for example, 2% to 5%) is a direction different from the light exit surface 16b on the light branch surface 21 (rightward in FIG. 1). ) And is guided to the outside from the side surface 16 c of the integrator rod 16. This light L1 is used for monitoring (described later) the amount of light on the irradiated surface 10a. Note that most of the light transmitted through the light branching surface 21 becomes a light image in which the light amount distribution is made uniform in the light emitting surface 16b (that is, a surface conjugate to the irradiated surface 10a) as described above.

  In the illumination optical device 10 according to the first embodiment, the fly-eye lens 17 and the condenser lens 18 are arranged at the subsequent stage of the integrator rod 16, and these optical elements (17, 18) are used for the light emitting surface 16 b of the integrator rod 16. An optical image is projected on the irradiated surface 10a. The irradiated surface 10a is conjugate with the optical image surface, and the light emitting surface 16b of the integrator rod 16 is disposed on the optical image surface. As described above, since the cross section of the integrator rod 16 is rectangular and the light image of the light emitting surface 16b is rectangular, the light image projected on the irradiated surface 10a (that is, the illumination area) is also rectangular. Further, since the light amount distribution of the light image on the light emitting surface 16b is made uniform, the light image (that is, the illumination area) on the irradiated surface 10a also has a uniform light amount distribution.

  Further, the fly-eye lens 17 includes a plurality of two-dimensionally arrayed lens elements (whose cross section is rectangular), and the entire cross-sectional shape of these lens elements substantially matches the cross-sectional shape of the integrator rod 16. It is a stack. The light entrance surface 17a of the fly-eye lens 17 is disposed in the vicinity of the light exit surface 16b of the integrator rod 16 (that is, a surface conjugate with the irradiated surface 10a). The light exit surface 17 b is disposed on a plane conjugate with the pupil plane of the condenser lens 18. The pupil plane of the condenser lens 18 corresponds to the pupil plane of the optical element (17, 18) that projects the light image of the light exit surface 16b onto the irradiated surface 10a. The pupil planes of the optical elements (17, 18) are arranged on a plane conjugate with the light exit surface 17b of the fly-eye lens 17.

  By providing the fly-eye lens 17, uniform light emitted from the light exit surface 16 b of the integrator rod 16 enters the fly-eye lens 17, receives a condensing action for each lens element, and enters the light exit surface 17 b. A plurality of light source images (that is, the same number as the lens elements) are formed. Further, a plurality of light source images on the light exit surface 17 b of the fly-eye lens 17 are projected onto the irradiated surface 10 a in a superimposed manner via the condenser lens 18.

  Therefore, the light amount distribution of the light image (that is, the illumination area) on the irradiated surface 10a is further uniformed (for example, ± 1) as compared with the light amount distribution of the light image on the light emitting surface 16b of the integrator rod 16. .5% or less). That is, the fly-eye lens 17 is a projection unit that projects a plurality of light source images onto the irradiated surface 10a together with the condenser lens 18, and the light quantity distribution is uniform by dividing the incident light and projecting it in a superimposed manner. It is also a production | generation means which produces | generates the opticalized image. A circular aperture stop (not shown) is disposed on the light exit surface 17b of the fly-eye lens 17, and the direction characteristic of the incident angle on the irradiated surface 10a is eliminated.

  Furthermore, the illumination optical device 10 of the first embodiment includes a light amount monitor 20 for monitoring the light amount of the optical image (that is, the illumination area) on the irradiated surface 10a. The light amount monitor 20 branches from the light branching surface 21 (for example, reflectivity 2% to 5%) disposed in the vicinity of the light emitting surface 16b of the integrator rod 16 and the side surface 16c of the integrator rod 16 after branching at the light branching surface 21. It is comprised with the photodetector 22 which receives the light L1 guide | induced to the exterior. Based on the output of the light detector 22, the amount of light on the irradiated surface 10a is monitored.

  The light L1 guided to the outside through the light branching surface 21 has a uniform light quantity distribution while propagating through the inside of the integrator rod 16 in the same manner as the light transmitted through the light branching surface 21 and reaching the light emitting surface 16b. Light. The light quantity distribution of the light L1 is schematically shown in FIG. FIG. 4 shows the relationship between the position in the direction parallel to the optical axis 10b of the illumination optical device 10 and the light quantity of the light L1.

  As can be seen from FIG. 4, the light amount of the light L <b> 1 shows a constant value B regardless of the position in the range A corresponding to the entire surface of the light branching surface 21. Further, such a light quantity distribution is the same in the direction perpendicular to the optical axis 10b. That is, it can be said that the light amount distribution of the light L1 is uniform within a rectangular range (A) corresponding to the entire surface of the light branching surface 21. In the first embodiment, since the light splitting surface 21 is inclined at 45 degrees, the uniformized range (A) of the light L1 is substantially the same shape as the light emitting surface 16b of the integrator rod 16.

  Therefore, even when the light detector 22 that is smaller than the light exit surface 16b of the integrator rod 16 is used and a part of the light L1 is selectively captured, the mounting position of the light detector 22 is “the light L1 is made uniform. If it is included in the “range (A)”, the same output can always be obtained. For this reason, it is possible to correctly monitor the amount of light on the irradiated surface 10a without strictly adjusting the mounting position of the photodetector 22 in advance.

  In addition, the amount of light can be correctly monitored even if the mounting position of the light detector 22 is slightly shifted during the use of the apparatus. Furthermore, since the photodetector 22 can be easily attached, there is an advantage that the assembly of the illumination optical device 10 is simplified. Further, since it is not necessary to arrange the light quantity monitor 20 between the condenser lens 18 and the irradiated surface 10a, a sufficient working distance can be secured.

  Furthermore, the amount of light on the irradiated surface 10a is monitored to check whether the irradiated surface 10a is irradiated with the desired amount of light (the amount of light according to the illumination condition of the inspection content). By rotating the density filter 13 or changing the power supplied to the light source 11, the light amount on the irradiated surface 10a can be maintained at a desired light amount. Therefore, the image sensor can be accurately inspected.

  In the first embodiment described above, the integrator rod 16 is manufactured by joining the glass members 23 and 24 shown in FIG. 3, but the present invention is not limited to this. As shown in FIG. 5, the integrator rod 16 may be manufactured by joining a rectangular parallelepiped glass member 27 and a cubic half prism 28 using the same adhesive. A half mirror coat is applied in advance to the inclined surface 28a of the half prism 28 at an oblique angle of 45 degrees, so that the inclined surface 28a becomes the light branching surface 21 in FIG.

Furthermore, in the first embodiment described above, the photodetector 22 smaller than the light exit surface 16b of the integrator rod 16 is used. However, even when a photodetector larger than the light exit surface 16b is used, The invention can be applied.
(Second Embodiment)
As shown in FIG. 6, the illumination optical device 40 of the second embodiment replaces the integrator rod 16, the fly eye lens 17, and the light amount monitor 20 of the illumination optical device 10 of FIG. A light amount monitor (41, 42) is provided, and the other configurations (11-15, 18) are the same as those of the illumination optical device 10 of FIG. Here, the integrator rod 46, the fly-eye lens 47, and the light amount monitor (41, 42) will be described.

  The integrator rod 46 is a rectangular parallelepiped glass member and does not have the light branching surface 21 as shown in FIG. Also in this integrator rod 46, an image of the light source 11 is formed on the light incident surface 46a, and the light emitting surface 46b is conjugate with the irradiated surface 40a of the illumination optical device 40. Then, the light incident on the integrator rod 46 becomes an optical image in which the light amount distribution is made uniform in the light emitting surface 46b (that is, a surface conjugate to the irradiated surface 40a).

  The fly-eye lens 47 is composed of a plurality of two-dimensionally arrayed lens elements (whose cross section is rectangular), and these lens elements are stacked such that the overall cross-sectional shape substantially matches the cross-sectional shape of the integrator rod 46. Is. The light incident surface 47 a of the fly eye lens 47 is in the vicinity of the light emitting surface 46 b of the integrator rod 46. The light exit surface 47 b is conjugate with the pupil surface of the condenser lens 18.

In the fly-eye lens 47, a circular aperture stop 43 (FIG. 7) is disposed on the light emitting surface 47b for the purpose of eliminating the direction characteristic of the incident angle on the irradiated surface 40a. For this reason, the light propagating through the lens elements arranged at the four corners toward the light emitting surface 47b becomes leaked light (that is, light that cannot reach the irradiated surface 40a).
Therefore, in the illumination optical device 40 of the second embodiment, the light amount monitor (41, 42) is configured by using the leakage light of the lens elements at the four corners. The light quantity monitor (41, 42) includes a light reflecting surface 41 provided so as to cross the four corner lens elements of the fly-eye lens 47 at an angle of 45 degrees, and a direction different from the light emitting surface 47b by the light reflecting surface 41. And a photodetector 42 that receives the leakage light L2 that is reflected to the outside of the fly-eye lens 47 and guided to the outside. The light reflecting surface 41 is a prism mirror. Based on the output of the photodetector 42, the amount of light on the irradiated surface 40a is monitored.

  As described above, the light entrance surface 47a of the fly-eye lens 47 is disposed in the vicinity of the light exit surface 46b of the integrator rod 46, and is uniform from the light exit surface 46b of the integrator rod 46 to the light entrance surface 47a of the fly-eye lens 47. Since light having a light quantity distribution is guided, a constant proportion of light is always distributed to the lens elements at the four corners. Then, a certain proportion of light is guided to the outside through the light reflecting surface 41 and becomes leaked light L2.

  Therefore, in the case where each leaked light L2 is captured using the photodetector 42 that is larger than the cross section of each lens element of the fly-eye lens 47, it is possible to irradiate without adjusting the mounting position of the photodetector 42 in advance. The amount of light on the surface 40a can be correctly monitored. In addition, the amount of light can be correctly monitored even if the mounting position of the photodetector 42 is slightly shifted during the use of the apparatus. Furthermore, since the mounting of the photodetector 42 is simple, there is an advantage that the assembly of the illumination optical device 40 is simplified. Further, since the leakage light L2 is taken in, there is no light amount loss on the irradiated surface 40a.

  Furthermore, the amount of light on the irradiated surface 40a is monitored to check whether the irradiated surface 40a is irradiated with the desired amount of light (the amount of light according to the illumination conditions of the inspection content). By rotating the density filter 13 or changing the power supplied to the light source 11, the light amount on the irradiated surface 40a can be maintained at a desired light amount. Therefore, the image sensor can be accurately inspected.

In the second embodiment described above, each of the lens elements at the four corners of the fly-eye lens 47 is provided with the light reflecting surface 41, and the leakage light L2 from each light reflecting surface 41 is guided to the photodetector 42. The present invention is not limited to this. A light reflecting surface may be provided in at least one of the lens elements at the four corners, and light leaked from the light reflecting surface may be taken in for monitoring.
(Third embodiment)
The illumination optical device of the third embodiment is provided with a fly eye lens 57 and a light amount monitor (51) shown in FIG. 8 in place of the fly eye lens 47 and the light amount monitor (41, 42) of the illumination optical device 40 of FIG. The other configurations (11 to 15, 46, 18) are the same as those of the illumination optical device 40 of FIG. Here, the fly-eye lens 57 and the light amount monitor (51) will be described.

  The fly-eye lens 57 includes a plurality of two-dimensionally arrayed lens elements (whose cross section is rectangular), and these lens elements are stacked so that the overall cross-sectional shape substantially matches the cross-sectional shape of the integrator rod 46. Is. The lens elements at the four corners do not have the light reflecting surface 41 as shown in FIG. All lens elements have the same shape. The light emitting surface 57 b of the fly eye lens 57 is conjugate with the pupil surface of the condenser lens 18.

Further, the fly-eye lens 57 has a circular aperture stop 53 disposed on the light exit surface 57b thereof, and the light that has passed through the aperture stop 53 is guided to the irradiated surface through the condenser lens 18. Yes.
Furthermore, in the illumination optical apparatus according to the third embodiment, light propagating through the lens elements disposed at the four corners toward the light emitting surface 57b (that is, leaked light that cannot reach the irradiated surface) is captured for monitoring. Therefore, a small opening (not shown) is provided in the light shielding portion of the aperture stop 53, and the photodetector 51 is arranged. In the third embodiment, a light amount monitor (51) is configured by the small aperture of the aperture stop 53 and the photodetector 51. Each photodetector 51 receives light that has propagated through the lens elements at the four corners and reached the light exit surface 57b. Based on the output of the light detector 51, the amount of light on the irradiated surface is monitored.

  In the illumination optical apparatus according to the third embodiment, light having a uniform light amount distribution is guided from the light exit surface 46b of the integrator rod 46 to the light incident surface of the fly-eye lens 57, and a constant proportion of light is always supplied to the lens elements at the four corners. Is distributed and this light is captured by the photodetector 51. For this reason, when using the photodetector 51 that is smaller than the cross-section of each lens element of the fly-eye lens 57 and larger than the small aperture of the aperture stop 53, the mounting position of the photodetector 51 need not be strictly adjusted in advance. The amount of light on the irradiated surface can be monitored correctly.

In the third embodiment described above, the photodetector 51 is provided in each of the four corner lens elements of the fly-eye lens 57, but the present invention is not limited to this. A light detector may be provided in at least one of the lens elements at the four corners to capture leakage light for monitoring.
In the third embodiment described above, the light amount monitor (51) is disposed on the light exit surface 57b of the fly-eye lens 57. However, when light emitted from the fly-eye lens 57 is further guided by a relay optical system, An aperture stop 60 (see FIG. 9) is disposed on a surface conjugate with the light exit surface 57b of the fly-eye lens 57 in the relay optical system without placing a light amount monitor on the exit surface 57b. The light amount monitor 61 may be arranged at 60a. In this case, the light amount is monitored by the light amount monitor 61 based on the light blocked by the aperture stop 60. Needless to say, the same effect can be obtained in this case. FIGS. 9A and 9B are a side view and a top view of the aperture stop 60 of the relay optical system.
(Modification)
In the above-described embodiment, an example of an illumination optical device in which an integrator rod and a fly-eye lens are combined has been described. However, the present invention is not limited to this. The present invention can also be applied to an illumination optical apparatus that uses each of the integrator rod and the fly-eye lens independently. When only the fly-eye lens is used, it is preferable to use a two-stage configuration and arrange the light amount monitor shown in FIG. 7 or FIG. The front-stage fly-eye lens functions as part of means for generating an optical image in which the light quantity distribution is uniform in a plane conjugate to the irradiated surface. The present invention can also be applied when the fly-eye lens has a single-stage configuration. The fly-eye lens having a single-stage structure functions as a projection unit that projects a light image with a uniform light amount distribution onto an irradiated surface together with the condenser lens.

  In the above-described embodiment, an example of an illumination optical device incorporated in a device for inspecting an image sensor such as a CCD or a CMOS has been described. However, the present invention is not limited to this. In addition, the present invention can also be applied to an illumination optical apparatus for a reticle of an exposure apparatus and an illumination optical apparatus for a biological microscope.

It is a figure which shows the whole structure of the illumination optical apparatus 10 of 1st Embodiment. 4 is a top view illustrating the density filter 13. FIG. It is a figure explaining the structure of the integrator rod. It is a figure explaining the light quantity distribution of the monitoring light L1 guide | induced to the exterior from the light branch surface 21 of the integrator rod 16. FIG. It is a figure explaining another structure of the integrator rod. It is a figure which shows the whole structure of the illumination optical apparatus 40 of 2nd Embodiment. It is a perspective view which shows the structure of the fly eye lens 47 and the light quantity monitor (41, 42). It is a perspective view which shows the structure of the light quantity monitor (51) of 3rd Embodiment. It is a figure which shows the structure of the aperture stop 60 of the relay optical system used for the modification of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,40 Illumination optical apparatus 10a Irradiated surface 11 Light source 12 Collector lens 13 Density filter 14 Filter group 15 Input lens 16, 46 Integrator rod 17, 47, 57 Fly eye lens 18 Condenser lens 19 Pupil position conversion adapter 20 Light quantity monitor 21 Light Branch surface 22, 42, 51 Photo detector 31 Probe 32 Signal processing device 41 Light reflection surface 43, 53 Aperture stop

Claims (7)

Generating means for generating a light image with a uniform light amount distribution;
Projecting means for projecting the optical image onto an irradiated surface conjugate with the optical image plane;
Monitoring means for monitoring the light quantity of the optical image projected on the irradiated surface,
The generating means includes an integrator rod, and the light emitting surface of the integrator rod is disposed on a surface conjugate with the irradiated surface,
The monitoring means has a light branching surface that branches a part of light propagating in the integrator rod toward the light emitting surface in a direction different from the light emitting surface in the vicinity of the light emitting surface, The illumination optical device characterized in that the light quantity is monitored based on the light branched at the light branching surface and guided to the outside of the integrator rod. The illumination optical apparatus according to claim 1,
The illumination optical device, wherein the light branching surface is provided so as to obliquely cross the integrator rod. Generating means for generating a light image with a uniform light amount distribution;
Projecting means for projecting the optical image onto an irradiated surface conjugate with the optical image plane;
Monitoring means for monitoring the light quantity of the optical image projected on the irradiated surface,
The projection means includes a fly-eye lens composed of a plurality of two-dimensionally arranged lens elements, and the pupil plane of the projection means is disposed on a plane conjugate with the light exit surface of the fly-eye lens,
The monitoring means includes a light reflecting surface that reflects light propagating through at least one of lens elements disposed at four corners of the fly-eye lens toward the light emitting surface in a direction different from the light emitting surface. And an illumination optical device characterized in that the light quantity is monitored based on light reflected by the light reflecting surface and guided to the outside of the fly-eye lens. The illumination optical apparatus according to claim 3.
The illumination optical device, wherein the light reflecting surface is provided so as to obliquely cross the lens element. Generating means for generating a light image with a uniform light amount distribution;
Projecting means for projecting the optical image onto an irradiated surface conjugate with the optical image plane;
Monitoring means for monitoring the light quantity of the optical image projected on the irradiated surface;
An aperture stop disposed on the light exit surface of the generation means or the pupil plane of the projection means,
The illuminating optical device characterized in that the monitoring means monitors the light quantity based on light blocked by the aperture stop. Generating means for generating a light image with a uniform light amount distribution;
Projecting means for projecting the optical image onto an irradiated surface conjugate with the optical image plane;
Monitoring means for monitoring the light quantity of the optical image projected on the irradiated surface,
The monitoring optical unit has a light branching surface disposed in the vicinity of the light image surface, and monitors the light quantity based on light branched by the light branching surface. A projecting means for projecting a light image having a uniform light amount distribution onto the irradiated surface;
Monitoring means for monitoring the light quantity of the optical image projected on the irradiated surface,
The projection means includes a fly-eye lens composed of a plurality of two-dimensionally arranged lens elements, and the pupil plane of the projection means is disposed on a plane conjugate with the light exit surface of the fly-eye lens,
The monitoring means includes a light reflecting surface that reflects light propagating through at least one of lens elements disposed at four corners of the fly-eye lens toward the light emitting surface in a direction different from the light emitting surface. And an illumination optical device characterized in that the light quantity is monitored based on light reflected by the light reflecting surface and guided to the outside of the fly-eye lens.

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