JP2002340786A - Device for adjusting quantity of light and illuminance and sample-inspecting apparatus with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a quantity of light of an illumination light to be adjusted without using a special optical member and continuously without steps. SOLUTION: A sample-inspecting apparatus inspects a defect or the like of a sample 11 by a lighting device (an integrating sphere 6 and a light trapping face 9) for illuminating the sample 11 with the illumination light having a predetermined illuminance, a pair of light guide means 3 and 4 for guiding the illumination light having the predetermined illuminance and emitted from an illumination light source 1 to the lighting device, and the illumination light having the predetermined illuminance and guided by the pair of guide means 3 and 4. The apparatus has means 14 and 15 set for adjusting an illumination quantity of light or an illumination illuminance to the sample 11 by adjusting a distance between an end face of the light guide means 3, 4 of the side of the light source 1 and an end face of the light guide means 3, 4 of the side of the sample 11 and by adjusting an incident amount of light from the light guide means 3, 4 of the side of the light source 1 to the light guide means 3, 4 of the side of the sample 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element such as an optical element to be inspected, and to detect defects (for example, scratches, coating flaws, chipped edges, etc.) within the effective aperture range of the optical surface to be inspected. And the like, and a light intensity illuminance adjustment device for inspecting the same and a sample inspection device provided with the same.

[0002]

2. Description of the Related Art Conventionally, surface defects of optical elements and the like are described in, for example, International Standard ISO 10110-1 "Optics and Optical Equipment-Drafting Techniques for Optical Elements and Systems-Part 1: General Rules" (First Edition, As described in March 16, 1996, surface defects (for example, optical defects such as optical lenses and prisms) within the effective aperture range of optical surfaces such as optical elements.
Standards of allowable levels for abrasions, foreign substances, adhesion marks), coating flaws, etc. are specified, but the standards of this level are applicable to both the transmission surface and the reflection surface of an optical element and the like, and are permitted. The surface defect level is applied in Method I, which is expressed in terms of the surface area impaired or affected by the defect, or Method II, which is inspected by the visibility of the defect. The present invention is directed to a sample inspection apparatus applied to the method II.

[0003] This type of sample inspection apparatus is schematically configured as shown in FIG. In FIG. 1, reference numeral 1 denotes a light source for emitting illumination light (for example, a xenon arc lamp); 2 to 4, fiber optics; 5 a spectral beam splitter; The illumination light from the light source passes through the fiber optics 2 and enters the beam splitter 5. The beam splitter 5 bisects the illumination light from the fiber optics 2 and distributes the light to the fiber optics 3 and 4. The fiber optics 3 guides illumination light to an illumination light inlet 7 of an integrating sphere 6 as an illumination device described later. The fiber optics 4 directs the illumination light to a reflecting mirror 8 providing a gray background. The inner surface of the integrating sphere 6 is coated with a diffusible paint and has a white color.

[0004] 9 is a black optical trapping surface, 10 is an integrating sphere 6
The light emission port 11 is a sample, and the illumination light incident from the illumination light introduction port 7 is uniformly dispersed by the integrating sphere 6 and the light trapping surface 9. The sample 11 is disposed at the light emission port 10 of the integrating sphere 6, and the sample 11 is transmitted and illuminated by the illumination light.

Reference numeral 12 denotes a photosynthesis beam splitter.
The beam splitter 12 combines the transmitted illumination light from the sample 11 and the background light from the reflection mirror 8. When the inspector looks into the sample 11 through the beam splitter 12,
The sample 11 can be seen in the gray background. At this time,
When a reference sample is used as the sample 11, the pattern becomes invisible. By adjusting the background light to the minimum amount of light, individual differences can be eliminated. Thereby, the observation of the sample 11 can be performed.

The fiber optics 3 is provided with a light intensity illuminance adjusting member (for example, an ND filter) 13, which is used for adjusting the light intensity of the illumination light incident on the integrating sphere 6.

The fiber optics 4 is provided with a light intensity illuminance adjusting member (for example, an ND filter, a diaphragm) 14. The light intensity illuminance adjusting member 14 is used for adjusting the incident light amount of the background light incident on the reflection mirror 8.

[0008]

However, in this conventional apparatus, it is necessary to arrange a stop or an ND filter in the optical path of the illumination system, so that adjustment or switching requires time and effort.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sample inspection apparatus capable of adjusting the amount of illumination light without using a dedicated optical member.

It is another object of the present invention to provide a sample inspection apparatus capable of adjusting the amount of illumination light in a stepless manner.

[0011]

According to a first aspect of the present invention, there is provided a sample inspection apparatus for illuminating a sample with illumination light having a predetermined illuminance, and guiding illumination light emitted by an illumination light source to the illumination apparatus. A pair of light guide means for inspecting a sample with illumination light of a predetermined illuminance guided by the pair of light guide means, wherein an end face of the light guide means on the side of the illumination light source. By adjusting the distance between the light guide means on the sample side and the end face of the light guide means on the sample side, by increasing or decreasing the amount of light incident on the light guide means on the sample side from the light guide means on the light source side, the irradiation light amount or irradiation illuminance on the sample is increased. A light quantity illuminance adjusting means for adjusting is provided.

According to a second aspect of the present invention, there is provided a sample inspection apparatus comprising:
The illumination device is characterized in that the sample is illuminated from behind or from the front of the sample.

[0013]

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

FIG. 2 is an optical diagram showing an outline of the sample inspection apparatus according to the first embodiment of the present invention. Here, the fiber optics 3 and 4 are composed of light guide means 3A and 4A on the illumination light source 1 side and light guide means 3B and 4B on the sample 11 side, and a rod lens 19 is provided on an end face of the light guide means 3A and 4A. A rod lens 20 is provided on the end faces of the light guide means 3B, 4B as shown in FIG. Rod lens 19, 2
0 is provided on the metal tube 17, and the rod lens 19 is fixed by screws 21. The rod lens 20 is fixed by a positioning adjustment screw 22. The end surfaces of the rod lenses 19 and 20 are opposed to each other, and the rod lens 20 can slide in the metal tube 17 by loosening the positioning adjustment screw 22. Is adjusted, the amount of illumination light incident on the rod lens 20 from the rod lens 19 is increased or decreased. That is,
The rod lenses 19 and 20 function as light amount illuminance adjustment means, and light amount and illuminance can be adjusted by loosening the positioning adjustment screw 22 and changing the position of the rod lens 20.

Therefore, the amount of light incident on the integrating sphere 6 and the reflecting mirror can be appropriately adjusted with a simple structure, and the sample 11 can be observed well.

If the distance between the opposing rod lenses 19 and 20 is changed, the light quantity incident on the rod lens 20 changes continuously, so that the light quantity illuminance can be easily and continuously adjusted. In addition, the stop position can be gradually changed by adding a preset operation. For example, after accurately adjusting the stop position of the illumination illuminance 2500 lx ± 5, 1250 lx ± 5%, 625 lx ± 5%, 310
lx ± 5% FIG. 4t shows a sample inspection apparatus according to the second embodiment, and shows a reflection inspection test apparatus. Here, the illuminating device includes the integrating sphere 28 and the black light shielding plate 32, and a light emission port 33 is formed in the center of the light shielding plate 32. The sample 11 is mounted on the bottom of the integrating sphere 28, and its reflected light is emitted outside through the light emission port 33 of the light shielding plate 32. In this case, when the inspector looks into the light emission port 33 through the beam splitter 34, the sample 11 can be seen in a gray background.

According to the present invention, it is possible to adjust the light intensity and illuminance without any special additional material for attenuation. Further, according to the present invention, a very small amount of light and illuminance can be adjusted steplessly.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of a sample inspection apparatus according to a conventional technique.

FIG. 2 is a schematic diagram illustrating an outline of a sample inspection apparatus according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram showing a main part of the device shown in FIG. 2;

FIG. 4 is a schematic diagram illustrating an outline of a sample inspection apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source 2-4 ... Fiber optics 5, 12 ... Beam splitter 6, 28 ... Integrating sphere 7, 29 ... Illumination light introduction port 8 ... Gray background color reflection mirror 9 ... Light trap 10, 33 ... Light emission port 15, 16 , 35,36 ... Light intensity illuminance adjustment device

Claims (4)

[Claims] An illumination device for irradiating a sample with illumination light having a predetermined illuminance, and a light amount adjusting device including a pair of light guide means for guiding illumination light emitted by an illumination light source to the illumination device. In the above, the distance between the end face of the light guide means on the illumination light source side and the end face of the light guide means on the sample side is adjusted to increase or decrease the amount of incident light from the light guide means on the illumination light source side to the light guide means on the sample side. The light amount illuminance adjusting device adjusts the irradiation light amount or the irradiation illuminance on the sample. 2. An illumination device for irradiating a sample with illumination light of a predetermined illuminance, and a pair of light guide means for accompanying illumination light emitted by an illumination light source to the illumination device. In a sample inspection apparatus for inspecting a sample by a predetermined scorched earth illumination light guided by a light guide unit, a distance between an end surface of the light guide unit on the illumination light source side and an end surface of the sample side light guide unit is adjusted, A sample inspection apparatus, comprising: a light amount illuminance adjusting unit that adjusts an irradiation light amount or an irradiation illuminance on the sample by increasing or decreasing the amount of incident light from the light guide unit on the illumination light source side to the sample side. 3. The illumination illuminance adjustment device according to claim 1, wherein the illumination device is configured to irradiate the sample from behind or from the front of the sample. 4. The sample inspection apparatus according to claim 2, wherein the illumination device is configured to illuminate the sample from behind or from the front of the sample.