JP2014092366A - Photometric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photometric device that can be improved in measurement precision by reducing an influence of rear-face reflection even when a rear surface of a sample to be measured tilts to a measured surface of the sample to be measured.SOLUTION: A photometric device 50 includes: a light source 1; a luminance flux shaping part 20 which shapes luminous flux from the light source 1 into measurement luminous flux Lhaving a cross-sectional shape and so sectioned orthogonally to the optical axis Othat a ring-shaped vacant part is formed in a part of a ring-shaped pattern in a peripheral direction; a light shield position change part which changes the formation position of the ring-shaped vacant part; an objective 6 which converges the measurement luminous flux Lon a measured surface of a sample to be measured; an image forming optical system 9 which converges reflected luminous flux, reflected by the sample 7 to be measured, of the measurement luminous flux L; an incidence opening diaphragm 10a arranged in optically conjugate position relation with the measured surface 7a across the image forming optical system 9; a spectroscope 10 which measures luminous flux passed through the incidence opening diaphragm 10a; and an observation optical system 14 which can observe a projection image by the image forming optical system 9 through the image forming optical system 9.

Description

  The present invention relates to a photometric device.

Conventionally, the measurement sample is irradiated with the measurement light beam, the reflected light beam of the measurement light beam on the measurement surface is collected, and the collected light beam is incident on a photometric means such as a spectroscope or a light receiving device to measure the light. A photometric device that performs the above is known.
For example, Patent Document 1 describes a reflectance measuring device that is an example of such a photometric device.
The reflectance measuring device includes an objective lens, an optical path splitting element disposed behind the objective lens, a light source that emits an annular light beam disposed in one optical path divided by the optical path splitting element, and A micro-aperture stop disposed in the other optical path divided by the optical path splitting element; and a light-sensitive element disposed behind the micro-aperture stop. A light beam emitted from the light source is passed through the optical path splitting element. The light beam is focused on the test surface by the objective lens, and the reflected light from the test surface is received by the light sensitive element through the objective lens, the optical path dividing element, and the minute aperture stop.
According to such a reflectance measurement apparatus, the measurement surface of the sample to be measured and the minute aperture stop are arranged in an optically conjugate positional relationship. Thereby, the surface reflected light of the surface to be measured enters the minute aperture stop and enters the photosensitive element. On the other hand, the back-surface reflected light on the back surface of the sample to be measured facing the surface to be measured is projected as a ring-shaped blurred image on the minute aperture stop, and is shielded by reaching the outside of the aperture of the minute aperture stop.
For this reason, it becomes possible to reduce the measurement noise resulting from back surface reflected light.

Japanese Examined Patent Publication No. 6-27706

However, the conventional photometric device as described above has the following problems.
In the reflectance measuring apparatus of Patent Document 1, when the measured surface and the back surface are parallel, the reflected light beam on the measured surface and the back surface reflected light on the back surface travel on the same axis, so that the back surface reflected light is shielded. The
However, when the back surface is inclined with respect to the surface to be measured, the center of the back surface reflected light on the minute aperture stop deviates from the optical axis of the measurement light beam. Some may enter the aperture of the minute aperture stop.
For this reason, there is a problem that the back-surface reflected light incident on the aperture of the minute aperture stop becomes measurement noise and the optical characteristics of the surface to be measured cannot be measured accurately.

  The present invention has been made in view of the above problems, and even when the back surface of the sample to be measured is tilted with respect to the surface to be measured of the sample to be measured, measurement is performed while reducing the influence of back surface reflection. An object of the present invention is to provide a photometric device capable of improving accuracy.

  In order to solve the above-described problem, a photometric device according to the first aspect of the present invention includes a light source and a light beam emitted from the light source in a circumferential direction of a ring-shaped pattern in a cross section orthogonal to the optical axis. A light beam shaping unit that can be shaped into a measurement light beam having a cross-sectional shape in which an annular zone defect portion is formed, a light-shielding position changing unit that changes a formation position of the annular zone defect portion, A first condensing optical system for condensing on a measurement surface; a second condensing optical system for condensing a reflected light beam reflected by the sample to be measured out of the measurement light beam; and the second light collecting system. An aperture stop disposed in an optically conjugate positional relationship with the surface to be measured across an optical optical system, a photometric unit that measures a light beam that has passed through the aperture stop, and the second condensing optical system The second condensing optical system in the image plane optically conjugate with the surface to be measured. Projected image and the observation unit observable, the configuration with that.

  In the photometric device, the light beam shaping unit is provided with an annular aperture stop in which an annular aperture is formed, and is movable with respect to the aperture, and shields a part of the aperture of the annular aperture stop. A light shielding member that forms the annular zone defect portion of the measurement light beam, and the light shielding position changing portion holds the light shielding member movably with respect to the opening of the annular aperture stop. Can be provided.

  In the photometric device provided with the light shielding member moving unit, the light shielding member moving unit is capable of rotating the light shielding member along the circumferential direction of the opening.

  In the photometric device, the light beam shaping unit includes a diaphragm member having an opening shape in which a light shielding region is formed in a part of a ring-shaped pattern in the circumferential direction, and the light shielding position changing unit moves the diaphragm member to the ring-shaped pattern. It is possible to rotate and move in the circumferential direction of the pattern.

  The photometric device of the present invention can shield a part of the measurement light beam that is reflected from the back surface and reaches the aperture stop aperture by changing the formation position of the annular zone defect portion of the measurement light beam by the light shielding position changing unit. Therefore, even when the back surface of the sample to be measured is inclined with respect to the measurement surface of the sample to be measured, the effect of reducing the influence of the back surface reflection and improving the measurement accuracy is achieved.

It is a typical block diagram which shows schematic structure of the photometry apparatus of the 1st Embodiment of this invention. FIG. 2 is a schematic perspective view showing an A view in FIG. 1, a BB cross-sectional view in the A view, and a measurement light beam emitted from a light beam shaping unit. FIG. 4 is a schematic diagram showing an example of the state of an image plane and a schematic optical path diagram in the case where the sample to be measured is parallel to the surface to be measured and does not have a light beam shaping unit. FIG. 6 is a schematic diagram showing an example of a schematic optical path diagram and an image plane when the surface to be measured and the back surface are non-parallel and do not have a light beam shaping unit. The front view which shows operation | movement of the light beam shaping part and the light-shielding position change part in the photometry apparatus of the 1st Embodiment of this invention, The schematic diagram which shows an example of the mode of an image surface in case a to-be-measured surface and a back surface are parallel, It is a schematic diagram which shows an example of the mode of an image surface in case a to-be-measured surface and a back surface are non-parallel. It is a schematic diagram which shows the example of the observation image by the observation part before the movement of the light-shielding member of the photometry apparatus of the 1st Embodiment of this invention after a movement. FIG. 4 is a view as viewed in FIG. 1 showing a configuration of a main part of a photometric device according to a second embodiment of the present invention, and a cross-sectional view taken along a line CC in FIG. FIG. 4 is a view as viewed in FIG. 1 showing a configuration of a main part of a photometric device according to a third embodiment of the present invention, a DD cross-sectional view in the view as viewed in A, and an operation explanatory diagram. It is a schematic diagram which shows an example of the observation image by the observation part before and after light-shielding by the light beam shaping part of the photometry apparatus of the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A photometric device according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic configuration diagram showing a schematic configuration of a photometric device according to a first embodiment of the present invention. FIG. 2 (a) is a view on A in FIG. FIG. 2B is a BB cross-sectional view in FIG. FIG. 2C is a schematic perspective view showing the measurement light beam emitted from the light beam shaping unit.

  As shown in FIG. 1, the photometric device 50 according to the present embodiment is arranged in the same manner as the measured surface 7 a that is the surface of the measured sample 7 (measured sample) facing the photometric device 50, or the like. The reference measurement surface 70a (measurement surface) of the reference measurement sample 70 (measurement sample) whose spectral reflectance is known is incident on the surface to measure the spectral intensity of the measurement surface 7a and the reference measurement surface 70a. The ratio of the measured values of the spectral intensity obtained by the above measurement is obtained, and the relative spectral reflectance of the measured surface 7a is calculated based on the known spectral reflectance of the reference measurement surface 70a.

The sample 7 to be measured is not particularly limited, and examples thereof include optical elements such as lenses, optical filters, and reflection mirrors. 1 is a schematic diagram, the sample 7 to be measured is drawn in a flat plate shape. However, in the case of a lens or a curved mirror, the surface 7a to be measured may be a curved surface. Further, the back surface 7b located on the opposite side to the photometric device 50 in the sample 7 to be measured can be curved.
Further, even when the measured surface 7a and the back surface 7b are flat, they are not necessarily parallel to each other and can be inclined with respect to each other.
The thickness of the sample 7 to be measured is not limited. For example, a thin shape of 1 mm or less is also possible.
In the case of a lens, the distance between the measured surface 7a and the back surface 7b is generally changed depending on the measurement location. At the outer peripheral part of the convex lens and the central part of the concave lens, for example, a thin shape of 1 mm or less Sometimes it becomes.

  In the present embodiment, the reference sample 70 is a parallel plate, but the reference measurement surface 70a and the back surface 70b located on the opposite side of the photometry device 50 across the reference measurement surface 70a are separated by 10 mm. Yes. For this reason, even if there is a manufacturing error in the parallelism between the reference measurement surface 70a and the back surface 70b, the reflected light beam (back surface reflected light) from the back surface 70b is not likely to be measurement noise.

The schematic configuration of the photometric device 50 includes a light source 1, an illumination lens 2, a pinhole diaphragm 3, a collimator lens 4, a half mirror 5, an objective lens 6 (first condensing optical system and second condensing optical system), and holding A table 19, an imaging lens 8 (second condensing optical system), an observation optical system 14 (observation unit), a spectroscope 10 (photometry unit), a display monitor 15, a measurement control unit 16, and an operation unit 17 are provided.
Among these, the holding table 19, the objective lens 6, the half mirror 5, the imaging lens 8, the observation optical system 14, and the spectroscope 10 are the measurement reference axis O of the photometric device 50 defined by the incident optical axis of the spectroscope 10. Above, they are arranged in this order.

Light source 1 is for generating a measuring beam L ₀ for illuminating a surface to be measured 7a (reference measuring surface 70a), it is possible for example to adopt a halogen lamp or a deuterium lamp. Further, depending on the purpose of measurement, it is possible to employ a light source composed of a light emitting element such as a light emitting diode.
The illumination lens 2 is an optical element that illuminates the pinhole diaphragm 3 with the measurement light beam L ₀ generated by the light source 1.
Aperture pinhole 3 is a diaphragm member to limit the passing range of the measurement light beam L _0, which is illuminated by the illumination lens 2 in a range inside of the pinhole 3a.

Collimator lens 4, to a parallel beam of measurement beam L ₀ emitted from the pinhole diaphragm 3, which is arranged lens or lens group to match the focal position pinhole diaphragm 3.

Beam shaping unit 20 is for shaping the measuring beam L _0, which is collimated, the measuring beam L _1. Measuring beam L _1, as shown in FIG. 2 (c), in a cross section perpendicular to the optical axis O _0, zonal defects D on a part of circumferential direction of the annular pattern (see FIG. 2 (c)) Is a parallel light flux having
The light beam shaping unit 20 is supported by a support member (not shown), and is disposed on the optical path of the measurement light beam L ₀ that has passed through the collimator lens 4 as shown in FIG.
As shown in FIGS. 2A and 2B, the light beam shaping unit 20 includes an annular aperture stop 21, a light shielding member 22, a rotation support shaft 23, a movement operation unit 24 (light shielding position changing unit, light shielding member moving unit). And a position holding member 25.

The annular aperture stop 21 is a plate-like aperture member having an annular aperture 21a (annular aperture) centered at a point P ₂₁ (see FIG. 2A), as shown in FIG. , perpendicular to the optical axis _{O 0,} the optical axis _{O 0} is disposed at a position passing through the point _{P 21.} Hereinafter, the point _{P 21,} referred to as annular central point _{P 21.}
The opening 21a can be formed in a complete annular shape or a pseudo annular shape.
The quasi-annular shape means a shape having a substantially annular shape as a whole, although the annular shape is discontinuous in the circumferential direction. For example, a linear portion for connecting the inner peripheral portion and the outer peripheral portion of the opening 21a is formed in a part, and one or more openings excluding the linear portion are arranged in a substantially annular shape as a whole. Examples of the shape can be given.
The annular aperture stop 21 can be constituted by, for example, a metal plate in which the shape of the opening 21a is punched or a glass plate in which a light shielding layer is formed in a region excluding the opening 21a.

Light blocking member 22, across the opening 21a of the annular aperture stop 21 in the radial direction, by shielding a part of the opening 21a, be a member forming the annular defect D of the measuring beam L ₁ , Consisting of a strip-like plate member elongated in one direction.
At one end portion in the longitudinal direction of the light shielding member 22, a bearing portion 22 a that is rotatably connected to a rotation support shaft 23 described later is formed.
Longitudinal length of the light shielding member 22, when placing the end portion in the longitudinal direction in the zonal center point P _21, the other end portion in the longitudinal direction is a length which can cross the opening 21a.
The width of the light blocking member 22 in the short direction is appropriately set according to the size in the circumferential direction required for the annular zone missing portion D. For example, it is possible to make the size about 1/6 to 1/3 of the circumferential direction of the opening 21a.
As the material of the light shielding member 22, for example, a metal plate or a synthetic resin having no light transmittance can be employed.

The rotation support shaft 23 is a shaft member that is rotatably connected to the bearing portion 22 a of the light shielding member 22, and is erected on the annular zone center point P ₂₁ of the annular zone aperture stop 21.
The movement operation unit 24 is a rod-like member fixed along the longitudinal direction at an end opposite to the bearing unit 23 in the longitudinal direction of the light shielding member 22 in order to manipulate the rotational movement of the light shielding member 22.
The moving operation unit 24 has a leading end in the extending direction exposed at a position where the operator can operate from the outside of the photometric device 50.

The position holding member 25 is engaged so that the intermediate portion in the longitudinal direction of the moving operation unit 24 is sandwiched from the axial direction of rotation so that the moving operation unit 24 can be rotated and the position can be held when the rotation is stopped. It is a member to stop.
As the configuration of the position holding member 25, for example, an elastic member that generates a frictional force that resists rotational movement, an elastic member that has fine corrugations that can be overcome by a constant operating force, and the like can be employed.
Even if the position holding member 25 is not used, for example, when the light shielding member 22 is not moved during photometry due to the weight of the moving operation unit 24 and the light shielding member 22, the position holding member 25 is used. An omitted configuration is also possible.

As shown in FIG. 1, the half mirror 5 is an optical path dividing unit that reflects a part of the measurement light beam L ₁ transmitted through the light beam shaping unit 20 toward the objective lens 6 and guides it to the objective lens 6.

The objective lens 6, the measuring beam L ₁ reflected by the half mirror 5, the measuring light beam L on the surface to be measured 7a (reference measuring surface 70a) of the measured sample 7 is disposed below (reference sample to be measured 70) as well as condensed as _2, a lens or a lens group for focusing the measuring beam L ₃ reflected by the measurement surface 7a (the reference measuring surface 70a).
The lens optical axis of the objective lens 6 is aligned with the measurement reference axis O.
Therefore, the objective lens 6 constitute the first condensing optical system for condensing the measuring beam L ₁ on the measured surface 7a (the reference measuring surface 70a).

The holding table 19 is configured so that the measured sample 7 (reference measured sample 70) has a measured surface 7a (reference measured surface 70a) perpendicular to the measurement reference axis O and coincides with the focal position of the objective lens 6. It is something to hold.
In the present embodiment, the structure of the holding table 19 includes a holding unit 19a that holds the sample 7 to be measured (reference measured sample 70), an inclination stage 19b that adjusts an inclination angle of the holding unit 19a with respect to the measurement reference axis O, An XYZ moving stage 19c that moves the tilt stage 19b in a direction orthogonal to the measurement reference axis O and a direction along the measurement reference axis O is provided.
For this reason, the measurement surface 7a (reference measurement surface 70a) held by the holding portion 19a of the holding table 19 is adjusted with respect to the measurement reference axis O by adjusting the posture and position by the tilt stage 19b and the XYZ moving stage 19c. And is held so as to coincide with the focal position of the objective lens 6. According to this arrangement, the image of the pinhole 3a is adapted to be projected into a spot shape by the measurement light beam L ₀ generated by the light source 1.
Note that the holding table 19 is simply arranged with the sample to be measured 7 (reference measurement sample 70), the measurement surface 7a (reference measurement surface 70a) is perpendicular to the measurement reference axis O, and the focus of the objective lens 6 is reached. As long as it can hold | maintain so that it may correspond to a position, you may delete at least any one of the inclination stage 19b and the XYZ movement stage 19c.

Imaging lens 8 is converged by the objective lens 6, the measuring beam L ₄ passing through the half mirror 5 as a measuring beam L ₅ is condensed, the opening 10b of the incident aperture stop 10a of the spectrometer 10 to be described later The image is formed.
For this reason, the image forming optical system 9 including the objective lens 6 and the image forming lens 8 optically converts the measured surface 7a (reference measurement surface 70a) and the image surface I ₀ on which the entrance aperture stop 10a is disposed. The positional relationship is conjugate.
Further, the image-forming optical system 9, of the measuring beam L _1, constitute a second condensing optical system for condensing the reflected light beam reflected by the sample to be measured 7 (reference sample to be measured 70).

The observation optical system 14 is for observing an image of the image plane I ₁ optically conjugate with the measurement surface 7 a (reference measurement surface 70 a) by the imaging optical system 9. In the present embodiment, the observation optical system 14, an optical path branching member 14a for branching the measurement light beam L ₆ the light condensed on the side of the measurement reference axis O by the imaging lens 8, is branched by the optical path branching member 14a It was provided with an eyepiece lens 14b to observe the image formed by the measurement light beam L _6.
For this reason, an image plane I ₁ equivalent to the image plane I ₀ on which the entrance aperture stop 10a is arranged is formed on the optical path between the optical path branching member 14a and the eyepiece lens 14b.
Although not shown, in the present embodiment, the optical path of the observation optical system 14, the image plane I _1, reference line for referring to the opening range of the opening portion 10b on the image plane I ₀ (the reticle) An aiming member for display is provided. In the present embodiment, a circular reference line or the like that matches the opening shape of the opening 10b is employed. However, the reference line may have a pattern in which the distance and direction from the center of the opening 10b can be referred to. For example, it is possible to adopt a reference line provided radially at a certain angle, a reference line combining a radial pattern and a concentric pattern, a grid-like reference line, or the like.
In the observation optical system 14, an imaging camera may be arranged in place of the eyepiece 14b, and an image captured by the imaging camera may be displayed on a monitor so that it can be observed. In this case, since the reference line can be generated as image data and displayed superimposed on the captured image, the aiming member in the observation optical system 14 can be omitted.

Spectrometer 10 includes a diffraction grating 11, the one-dimensional image sensor 12, and a control circuit 13, is decomposed into each wavelength the measurement light beam L ₅ incident from the incident aperture stop 10a by the diffraction grating 11, a one-dimensional This is a photometry unit that forms an image on different light receiving elements of the image sensor 12 and outputs an output signal corresponding to the amount of light received by each light receiving element of the one-dimensional image sensor 12 to the measurement control unit 16.
Incident aperture stop 10a is, for guiding the measuring light beam is imaged by the imaging optical system 9 to the spectrometer 10, at the outer periphery of the spectroscope 10, arranged on the image plane I ₀ of the image-forming optical system 9 plate It is a shaped member. The incident aperture stop 10a is provided with an aperture 10b formed of a small pinhole passing through the incident aperture stop 10a. The inner diameter of the opening 10b is set to an appropriate diameter that is slightly larger than the imaging spot formed by the imaging optical system 9.
The entrance aperture stop 10a constitutes an aperture stop disposed in an optically conjugate positional relationship with the measured surface 7a with the imaging optical system 9 interposed therebetween.

The one-dimensional imaging device 12 includes, for example, a plurality of light receiving elements formed of photodiodes arranged in a line, and a reading unit such as a shift register that sequentially reads out the accumulated charges of each light receiving element and extracts them as video signals. .
The control circuit 13 is a control circuit that supplies a drive clock and a start pulse signal to the one-dimensional image sensor 12 and reads out the accumulated charge of each light receiving element as a video signal. The control circuit 13 is electrically connected to the one-dimensional image sensor 12 and the measurement control unit 16. Connected.
The control circuit 13 may be configured to A / D convert the video signal and send the digitized output signal to the measurement control unit 16, or send the video signal to the measurement control unit 16. Alternatively, the measurement control unit 16 may perform the configuration. In the following description, as an example, the output signal from the control circuit 13 is assumed to be digitized.

The measurement control unit 16 performs overall control of the photometric device 50 and is electrically connected to the spectroscope 10. For example, the measurement control unit 16 performs arithmetic processing on the output signal sent from the spectroscope 10 to obtain the relative spectral reflectance. It is possible to calculate, set an accumulation time in the control circuit 13, and control the light receiving operation of the spectrometer 10.
The measurement control unit 16 includes a display monitor 15 that displays information on output signals and relative spectral reflectances sent to the measurement control unit 16 as graphs and numerical information, and an operation input to the measurement control unit 16. Are connected to an operation unit 17 including a mouse, operation buttons, and the like.

  The apparatus configuration of the measurement control unit 16 includes a computer including a CPU, a memory, an input / output interface, an external storage device, and the like. The program is to be executed.

Next, the operation of the photometric device 50 of this embodiment will be described.
FIGS. 3A and 3B are schematic optical path diagrams in the case where the sample to be measured is parallel to the measured surface and the back surface and no light beam shaping unit, and an example of the state of the image surface. It is a schematic diagram which shows. 4A and 4B are schematic optical path diagrams in the case where the surface to be measured and the back surface are non-parallel and do not have the light beam shaping unit, and a schematic diagram illustrating an example of the state of the image plane. FIG. FIG. 5A is a front view showing operations of the light beam shaping unit and the light shielding position changing unit in the photometric device according to the first embodiment of the present invention. FIGS. 5B and 5C are schematic views showing an example of the state of the image surface when the measured surface and the back surface are parallel, and the state of the image surface when the measured surface and the back surface are non-parallel. It is a schematic diagram which shows an example. FIGS. 6A and 6B are schematic diagrams illustrating examples of images observed by the observation unit before and after the movement of the light shielding member of the photometric device according to the first embodiment of the present invention.

In order to measure the relative spectral reflectance of the sample 7 to be measured by the photometric device 50, spectral reflectance data R _a (λ), R _b (λ) of the reference sample 70 and the sample 7 to be measured are measured. Then, using the relative spectral reflectance data R _theory (λ) on the reference measurement surface 70a of the reference measurement sample 70 stored in advance in the measurement control unit 16, the relative spectrum of the measurement surface 7a can be calculated from the following equation (1). The reflectance data R _result (λ) is calculated. Here, λ represents a wavelength, and has a range according to the measurement purpose, such as 380 nm to 800 nm.

  The spectral reflectance measurement of the reference sample 70 and the sample 7 can be performed in substantially the same manner. In the present embodiment, either measurement may be performed first. In the following, the measurement operation will be described first by taking the spectral reflectance measurement of the sample 7 to be measured as an example, and then the measurement of the reference sample 70 will be described focusing on the points different from the measurement of the sample 7 to be measured.

  First, as shown in FIG. 1, the measurer holds the measured sample 7 on the holding table 19 so that the measured surface 7 a faces the objective lens 6. When the position and orientation of the surface to be measured 7a are not adjusted, the light source 1 is turned on, the spot image on the surface to be measured 7a is observed through the observation optical system 14, and the XYZ moving stage 19c of the holding table 19 is tilted. Position adjustment is performed using the stage 19b, and the measured surface 7a is aligned with the focal position of the objective lens 6 and arranged in a posture orthogonal to the measurement reference axis O.

  Next, the measurer performs an operation input for starting the measurement of the spectral intensity from the operation unit 17. As a result, the measurement control unit 16 outputs a control signal or the like to the control circuit 13 to start the light receiving operation of the spectrometer 10.

Here, the optical path in the photometric device 50 will be described.
As shown in FIG. 1, the measurement light beam L ₀ emitted from the light source 1 is collected by the illumination lens 2, thereby illuminating the pinhole diaphragm 3. Pinhole 3a of the pinhole diaphragm 3, since it is arranged at the focal position of the collimator lens 4, the measurement light beam transmitted through the pinhole 3a L ₀ is emitted as parallel light beam incident on the collimator lens 4, a beam shaping unit 20 is incident.

Measuring beam incident on the beam shaping unit 20 L _0, as shown in FIG. 2 (c), is shaped into a measuring beam L ₁ is a parallel beam C-shaped cross section having annular defect D, a half mirror Reach 5 Here, the position of the annular zone missing portion D around the optical axis O ₀ corresponds to the position of the light shielding member 22 on the opening 21a, and when the light shielding member 22 is rotationally moved, as will be described later, the rotational position thereof. It changes according to.

In the half mirror 5, as shown in FIG. 1, a part of the measurement light beam L ₁ is reflected to the objective lens 6 side and enters the objective lens 6 as an axial light beam that travels along the measurement reference axis O. It is condensed toward the focal point, and reaches the measurement surface 7a as measuring beam L _2.
An image of the pinhole 3 a corresponding to the optical magnification of the illumination optical system including the collimator lens 4 and the objective lens 6 is projected onto the focal plane of the objective lens 6.

In the measurement surface 7a, a portion of the reflected measuring beam L _2, is condensed and enters the objective lens 6 as a measuring beam L _3, incident on the half mirror 5 as a measuring beam L ₄ is a parallel light beam.
In the half mirror 5, a part of the measurement light beam L ₄ is transmitted, enters the imaging lens 8, is collected by the imaging lens 8, and reaches the optical path branching member 14 a of the observation optical system 14.

In the optical path branching member 14a, the optical path of the measurement beam L ₄ is the measuring light beam L ₅ for straight on measurement reference axis O passes through the optical path splitting member 14a, guide on the side of the measurement reference axis O by the optical path branching member 14a It is branched into measurement light beams L ₆ withering.
Measuring beam L ₅ represents, enters the opening 10b of the spectrometer 10, it is diffracted according to the wavelength by the diffraction grating 11 is focused at different positions on the one-dimensional image sensor 12, light receiving of a one-dimensional image sensor 12 Light is received by the element. As a result, a video signal corresponding to the charge amount of each light receiving element of the one-dimensional imaging element 12 is sent to the control circuit 13 and converted into an output signal corresponding to the amount of light received by each light receiving element. This output signal is sent to the measurement control unit 16 in accordance with a control signal from the measurement control unit 16.
On the other hand, the measurement light beam L ₆ enters the ocular lens 14b, an image on the surface to be measured 7a is observable. Thereby, for example, the position and posture of the measurement target surface 7a can be adjusted by observing this image.

Having described the optical path of the measuring beam L ₃ reflected from the measured surface 7a, the light beam is condensed by the imaging optical system 9 also includes reflected light beam at the rear surface 7b. The optical path of this reflected light beam will be described with reference to FIGS. 3A and 4A illustrating the optical path in the configuration in which the light shielding member 22 is omitted. For this reason, in FIGS. 3A and 4A, the cross-sectional shape of each measurement light beam is an annular shape except for the imaging position.
3A shows a case where the measured surface 7a and the back surface 7b are parallel, and FIG. 4A shows a case where the measured surface 7a and the back surface 7b ′ are non-parallel. The back surfaces 7b and 7b ′ are not necessarily flat surfaces, but are described as being flat surfaces for simplicity.

In the example shown in FIG. 3 (a), the measuring light beam L ₁₂ passing through the measurement surface 7a of the measuring beam L ₂ is spread annular proceeds to the medium of the sample 7, it is reflected by the rear surface 7b as the measurement light beam L ₁₃ emitted from the measured surface 7a, it enters the objective lens 6.
At this time, the measuring light beam L ₁₃ is a measuring beam L ₂ of P _a point is the imaging position becomes diffused light beam from the folding point P _b at the rear surface 7b. Incidentally, the point P _b is positioned on the object side of the point P _a to be on the measurement reference axis O.
For this reason, the measurement light beam L ₁₃ is collected by the objective lens 6 and the imaging lens 8 as shown as measurement light beams L ₁₄ and L ₁₅ , and the measurement light beam L ₅ depends on the magnification of the imaging optical system 9. from signed image in terms of the object side than the point that an imaging position Q _a Q _b, reaches the incident aperture stop 10a as diffused light beams.
Thus, looking at the incident aperture stop 10a from the image side, as shown in FIG. 3 (b), the measuring light beam L ₅ represents, but passes through the pinhole-like opening 10b, the measuring light beam L ₁₅ is the measuring light beam It is applied to the outer peripheral side of the opening 10b as annular beams spreading in concentric L _5. Thus, the measuring light beam _{L 15} is blocked by the incident aperture stop 10a.

In contrast, in the example shown in FIG. 4 (a), the measuring light beam L ₁₂ is the back surface 7b 'which is inclined with respect to the measurement surface 7a, is reflected in a direction crossing the measurement reference axis O. This reflected light beam is emitted from the measurement surface 7a as a measurement light beam L ₁₃ ′ and enters the objective lens 6.
Measurement beam L _{13 'is,} P _b point outside axis positioned on the object side than the point P _a' from, and is diffused light flux obliquely enters the objective lens 6.
Therefore, the measurement light beam L ₁₃ ′ is condensed by the objective lens 6 and the imaging lens 8 as shown as measurement light beams L ₁₄ ′ and L ₁₅ ′, and is measured according to the magnification of the imaging optical system 9. from signed image with than Q _a point is the imaging position of the L _{5 'Q b} a point located on the opposite side of _the' point P _b with respect to the object side and the measurement reference axis O, entrance aperture to diffuse into zonal The diaphragm 10a is reached.
For this reason, when the entrance aperture stop 10a is viewed from the image side, as shown in FIG. 4B, the measurement light beam L ₁₅ ′ is formed on the entrance aperture stop 10a as an annular beam decentered with respect to the measurement reference axis O. Irradiated. As a result, depending on the degree of eccentricity, the incident light beam F that is a part of the measurement light beam L ₁₅ ′ is transmitted through the opening 10b. The incident light beam F may be diffracted by the diffraction grating 11 in the spectroscope 10 and reach the one-dimensional image sensor 12. When the incident light beam F is received by the one-dimensional image sensor 12, a measurement error is caused.

  In the above description, when the back surfaces 7b and 7b 'are curved surfaces, only the imaging position is shifted according to the refractive power as the reflecting surface.

In the present embodiment, the annular zone deficient portion D is formed in a part of the measurement light beam L ₁ by being shielded by the light shielding member 22. The annular zone defect portion D can be moved in the circumferential direction of the measurement light beam L ₁ by rotating the light shielding member 22. For example, as shown in FIG. 5A, it is assumed that the light shielding member 22 is rotated and moved to a position indicated by a two-dot chain line in FIGS. 3A and 4A.
At this time, since the aperture shape formed by the aperture 21a and the light shielding member 22 is projected onto the entrance aperture stop 10a according to the magnification of the imaging optical system 9, the entrance aperture stop 10a is viewed from the image side. Then, a C-shaped optical image lacking a part of the annular zone indicated by a broken line in FIGS. 5B and 5C is projected. For reference, the corresponding position of the light shielding member 22 is drawn with a two-dot chain line in each figure.
In particular, in FIG. 5C, since the light shielding member 22 projects a light shielding portion by the light shielding member 22 in a region where the incident light flux F is formed, the incident light flux F disappears.
For this reason, in the photometric device 50, by rotating the light shielding member 22, a part or all of the incident light flux F, which is the back surface reflected light by the back surfaces 7b and 7b ′, can be prevented from entering the opening 10b. .

As a specific measuring operation, prior to the spectral reflectance measurement, measuring person observes the image surface I ₁ through the eyepiece 14b, changing the position of the light blocking member 22 as needed.
For example, as shown in FIG. 6A, in the field of view of the eyepiece 14b, the measurement light beam L ₆ in which the measurement light beams L ₅ and L ₁₅ ′ are branched together with the circular reference line 14c in the sighting member (not shown). , L ₁₆ ′, light images S ₆ and S ₁₆ ′ are observed. The optical image S ₁₆ ′ is a C-shaped image in which an annular zone deficient portion d is formed corresponding to the annular zone missing portion D in a part of the annular zone centered on the point O ₁₆ ′. In the present embodiment, the reference line 14c is equivalent to the opening shape of the opening 10b.
In the example shown in FIG. 6A, since the optical image S ₁₆ ′ is inside the reference line 14c, the measurer knows that the incident light flux F is generated.
Therefore, the measurer moves the light shielding member 22 by rotating the moving operation unit 24 around the rotation support shaft 23 while observing the optical image S ₁₅ ′ through the eyepiece 14b. As a result, the optical image S ₁₆ ′ rotates about the point O ₁₆ ′, and the position of the annular zone d is also rotated accordingly. Measurer becomes a positional relationship in the annular defect d covers the reference line 14c, to stop the rotation After verifying that the optical image S _{16 'is} located outside the reference line 14c.
Thereby, since the incident light flux F disappears, the measurement of the spectral reflectance can be started.

The measurement of the spectral reflectance is executed when the measurer performs an operation input for starting measurement through the operation unit 17.
That is, the measurement control unit 16 sends a control signal to the control circuit 13 to acquire an output signal from the control circuit 13 and stores this output signal together with information on the pixel position of the one-dimensional image sensor 12. Thereby, the spectral reflectance data R _b (λ) of the measured surface 7 a is stored in the measurement control unit 16.

Next, the measurer, remove the sample to be measured 7 from holder 19, in the same manner as described above, the reference measuring surface 70a and is held by the holding table 19, the reference measuring surface 70a, the measurement light beam L ₂ To do.
At this time, in this embodiment, since the back surface 70b of the reference sample 70 is sufficiently separated from the reference measurement surface 70a, there is no possibility that the reflected light beam reflected by the back surface 70b enters the opening 10b. For this reason, the measurer inputs the operation from the operation unit 17 without moving the position of the light shielding member 22 and performs the spectral reflectance measurement of the reference sample 70 to be measured.
That is, the measurement control unit 16 sends a control signal to the control circuit 13 to acquire an output signal from the control circuit 13 and stores this output signal together with information on the pixel position of the one-dimensional image sensor 12. Thereby, the spectral reflectance data R _a (λ) of the reference measurement surface 70a is stored in the measurement control unit 16.

  However, when the back surface reflected light of the reference sample 70 is incident on the opening 10b, the light shielding member 22 is moved and the incident light flux F is not generated in the same manner as the measurement of the sample 7 to be measured. Spectral reflectivity measurement may be started after forming.

Next, the measurement control unit 16 calculates the above equation (1) from the previously stored relative spectral reflectance data R _theory (λ) and the measured spectral reflectance data R _b (λ), R _a (λ). ) Is used to calculate the relative spectral reflectance data R _result (λ) of the measured surface 7a, and the calculation result is displayed on the display monitor 15 as, for example, a graph or numerical data.
The photometry of the sample 7 to be measured by the photometry device 50 is thus completed.

According to the photometric apparatus 50 of the present embodiment, by changing the formation position of the annular defect D of the measuring beam L ₁ by moving the light shielding member 22 by the moving operation part 24, the back reflecting to incident A part of the measurement light beam reaching the opening 10b of the aperture stop 10a can be shielded.
For this reason, even when the back surface 7b is inclined with respect to the measurement surface 7a of the sample 7 to be measured, the measurement accuracy can be improved by reducing the influence of the back surface reflection.

[Second Embodiment]
Next, a photometric device according to a second embodiment of the present invention will be described.
FIG. 7A is a view as viewed from A in FIG. 1 showing the configuration of the main part of the photometric device of the second embodiment of the present invention. FIG.7 (b) is CC sectional drawing in Fig.7 (a).

As shown in FIG. 1, the photometric device 51 of the present embodiment includes a light beam shaping unit 30 instead of the light beam shaping unit 20 of the photometric device 50 of the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

  As shown in FIGS. 7A and 7B, the light beam shaping unit 30 includes a rotation support shaft 32 provided on a support member (not shown), and a diaphragm member 31 rotatably supported on the rotation support shaft 32. The moving operation unit 33 (light-shielding position changing unit) fixed to the outer peripheral portion of the aperture member 31 and the position holding member 25 similar to the first embodiment are provided.

The central axis of the rotary shaft 32 is disposed so that the optical axis O ₀ coaxially.
The aperture member 31 is a plate-like member having a circular outer shape, and its center point P ₃₁ is coaxial with the rotation support shaft 32.
The throttle member 31 extends in concentric arc of around a center point P _31, the thickness direction pierced opening 31a (opening shape in which a part to the light shielding region in the circumferential direction is formed in the annular pattern) formed Has been.

The shape of the opening 31a is a C-shape that is a shape in which a part of the annular zone of the opening 21a of the first embodiment is interrupted, and the diameter of the inner peripheral portion and the outer peripheral portion is the opening portion 21a. Is consistent with the inner and outer diameters. Circumferential direction of the both end portions of the opening 31a, the center angle with respect to the center point _{P 31,} for example, are spaced apart so that the order of 240 ° to 300 °.
Therefore, between the circumferential opposite end portions of the opening 31a, for example, over a range of about 120 ° to 60 °, the light-shielding portion 31b shields the measuring light beam L ₀ (light shielding region) is formed.
Both ends of the opening 31a is not limited to the shape along the center point radially through P ₃₁ as in FIG. 7 (a), for example, be formed in parallel with the symmetry axis of the opening 31a Also good. In this case, the shape of the opening 31a is the same as that of the opening 21a of the first embodiment as long as the facing distance between both ends matches the width dimension in the short direction of the light shielding member 22 of the first embodiment. This is the same as the C-shape formed by overlapping the light shielding member 22.

The movement operation unit 33 is a member for performing an operation of rotating the entire diaphragm member 31 around the rotation support shaft 32, and a rod-like member similar to the movement operation unit 24 of the first embodiment is a diaphragm member. 31 is fixed in a posture extending along the radial direction.
The fixed position in the circumferential direction of the movement operation unit 33 is not particularly limited, but in the present embodiment, the position is overlapped with the axis of symmetry of the opening 31a. For this reason, the circumferential position of the movement operation unit 33 corresponds to the center position of the light shielding unit 31b.
Similar to the movement operation unit 24 of the first embodiment, the movement operation unit 33 can be rotated and moved by a pair of position holding members 25 arranged on the outer peripheral side of the diaphragm member 31 and at a position when rotation is stopped. It is locked so that it can be held.

According to such a photometric device 51, since the light beam shaping unit 30 includes the diaphragm member 31 including the light shielding unit 31b, the annular defect part D is rotationally moved by rotating the entire diaphragm member 31 by the movement operation unit 33. can do.
Therefore, the relative spectral reflectance measurement of the measurement surface 7a of the sample 7 to be measured is performed in the same manner as in the first embodiment except that the movement operation unit 33 is operated instead of the movement operation unit 24. It can be performed.
In this measurement, a part of the measurement light beam that reaches the opening 10b of the entrance aperture stop 10a by being reflected from the back surface can be shielded by the rotation operation by the movement operation unit 33.
For this reason, even when the back surface 7b is inclined with respect to the measurement surface 7a of the sample 7 to be measured, the measurement accuracy can be improved by reducing the influence of the back surface reflection.

[Third Embodiment]
Next, a photometric device according to a third embodiment of the present invention will be described.
FIG. 8A is a view as seen from A in FIG. 1 showing the configuration of the main part of the photometric device of the third embodiment of the present invention. FIG.8 (b) is DD sectional drawing in Fig.8 (a). FIG. 8C is an explanatory diagram of the operation of the main part of the photometric device of the third embodiment of the present invention.

As shown in FIG. 1, the photometric device 52 of the present embodiment includes a light beam shaping unit 40 instead of the light beam shaping unit 20 of the photometric device 50 of the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIGS. 8A and 8B, the light beam shaping unit 40 is arranged so as to be able to advance and retreat in the radial direction of the annular aperture stop 21 instead of the light shielding member 22 of the first embodiment. The light shielding plates 41A, 41B, 41C, and 41D (light shielding members) are provided.
The outer shape of the light shielding plates 41A, 41B, 41C, and 41D is a rectangular shape that can cover, for example, about 1/3 of the opening 21a of the annular aperture stop 21 from the outside in the radial direction. The members 43 are arranged in pairs in two axial directions orthogonal to each other. In the present embodiment, the light shielding plates 41A and 41C are arranged to face each other in the illustrated horizontal direction of FIG. 8A, and the light shielding plates 41B and 41D are arranged to face each other in the illustrated vertical direction of FIG. ing.
In the light shielding plates 41A, 41B, 41C, and 41D, rod-like movement operation portions 42 are fixed to the end portions on the retreat direction side for manipulating the advance / retreat amount.
Hereinafter, when the position of each light shielding plate is not a problem, the subscripts are omitted for simplicity, and the light shielding plates 41A, 41B, 41C, and 41D may be referred to as the light shielding plate 41 in some cases. The light shielding plates 41A, 41B, 41C, and 41D may be collectively referred to as the light shielding plates 41.

The light shielding plate holding member 43 is formed by penetrating a rectangular opening 43d having a size capable of surrounding the opening 21a from the outer peripheral side, and the opening 43d is formed radially outside the opening 43d. It has plane portions 43a extending in four directions at 90 ° in the radial direction with respect to the center.
Each flat surface portion 43a constitutes a sliding surface that holds each light shielding plate 41 so as to be movable, and guides the side surfaces of the light shielding plate 41 along the advancing / retreating direction of the light shielding plate 41 to both sides in the extending direction. A surface 43b is erected.
Further, at the end in the extending direction of each flat surface portion 43a, there is a forward / backward guide portion 43c that holds the movement operation portion 42 movably along the forward / backward direction of each light shielding plate 41 disposed on each flat surface portion 43a. Is provided.

With such a configuration of the light beam shaping unit 40, each light-shielding plate 41 on each plane unit 43a has a diameter that passes through the center of the opening 43d in accordance with the amount of operation of the moving operation unit 42 that is moved forward and backward by the measurer. Advance and retreat in the direction.
When the light shielding plate 41 advances, it can project from the opening 43d toward the center and cover a part of the opening 21a of the annular opening stop 21. In the present embodiment, for example, as shown in FIG. 8A, when the light shielding plate 41A is advanced to the maximum extent, for example, about 1/3 is covered in the radial direction of the opening 21a.
When the light shielding plate 41 is retracted, it can be retracted to a position on the outer peripheral side of the opening 21a of the annular aperture stop 21 so that it does not overlap the opening 21a.

Similarly, as indicated by a two-dot chain line in FIG. 8C, the other light-shielding plates 41B, 41C, and 41D also move between an advanced position that overlaps the opening 21a and a retracted position that does not overlap the opening 21a. Is possible.
Since the operation amount of the movement operation unit 42 can be changed steplessly, the range in which the light shielding plate 41A covers the opening 21a can be changed according to the advancement amount of the movement operation unit 42.

  In the present embodiment, as shown in FIG. 8C, the light shielding ranges of the respective light shielding plates 41 are partially overlapped. For this reason, each portion of the opening 21 a is shielded by any one of the light shielding plates 41. It has come to be.

Next, the operation of the photometric device 52 will be described focusing on the differences from the first embodiment.
FIGS. 9A and 9B are schematic diagrams illustrating an example of an observation image obtained by the observation unit before and after light shielding of the light beam shaping unit of the photometric device according to the third embodiment of the present invention.

In order to measure the relative spectral reflectance of the sample 7 to be measured by the photometric device 52 of the present embodiment, the spectral reflectances of the sample 7 to be measured and the reference sample 70 to be measured are substantially the same as in the first embodiment. Are measured in this order, and the relative spectral reflectance is calculated by the above equation (1).
Since the difference from the first embodiment is the difference in configuration between the light beam shaping unit 20 and the light beam shaping unit 40, the operation before the spectral reflectance measurement related to this point will be mainly described.

In the photometric device 52, each light shielding plate 41 of the light beam shaping unit 40 is retracted before measuring the spectral reflectance of the sample 7 to be measured. Therefore, the measuring beam L ₁ opening 10b not formed annular defect D in, also becomes zonal measuring light flux by back reflection of the back surface 7b.
Therefore, the observation image observed by the observation optical system 14 is, for example, as shown in FIG. 9A, a spot-like light image S ₆ corresponding to the measurement light beam L ₆ and a measurement light beam L ₁₆ due to back surface reflection. An annular optical image S ₁₆ 'corresponding to'.
The measurer looks at the position of the optical image S ₁₆ ′ entering the reference line 14c, and appropriately advances the light shielding plate 41 capable of forming the annular zone defect portion D at this position.
Thus, as the light shielding plate 41 is gradually overlapped with the opening 21a, as in the first embodiment, the measurement light beam L ₁ to the zonal defect D (not shown in in FIG. 9 (a)) is formed To go. However, the shape of the annular zone defect portion D is formed according to the way in which the light shielding plates 41 overlap, and is different from the shape shown in FIG.

For this reason, the measurement light beam L ₁₆ ′ also changes to a measurement light beam L ₁₆ ″ having a C-shaped cross section having an annular zone defect portion D, and as shown in FIG. 9B, the annular zone defect is transmitted through the eyepiece lens 14b. An optical image S ₁₆ ″ having a part d ″ is observed.
As shown in FIG. 9B, the measurer can confirm that the optical zone S ₁₆ ″ is located outside the reference line 14c by covering the reference line 14c with the annular zone d ′. The advancement of the light shielding plate 41 is stopped.
Thereby, since the incident light flux to the opening 10b by the reflected light flux on the back surface 7b disappears, the measurement of the spectral reflectance can be started.

Depending on the amount of inclination of the back surface 7b, the optical image S ₁₆ ′ may be located outside the reference line 14c without forming the annular zone defect d ″. In this case, since it is not necessary to form the annular zone deficient portion d ″, the spectral reflectance can be measured without the light shielding plates 41 being advanced. Therefore, since the light beam shaping unit 40 does not form an annular zone defect part in some cases, it is an example of a case where it can be shaped into a measurement light beam having an annular zone defect part.

Next, in the same manner as in the first embodiment, after measuring the spectral reflectance of the measurement target surface 7a, the measurement sample 7 is replaced with the reference measurement sample 70, and the spectral measurement of the reference measurement surface 70a is performed. Measure reflectivity.
At this time, the position of each light shielding plate 41 is not changed from the measurement position of the sample 7 to be measured. Thus, it is possible to match the time of measurement of the measurement surface 7a, the light amount of the measuring beam L ₁ at the time of measurement of the reference measuring surface 70a.

According to such a photometric device 52, the formation position and size of the annular zone defect portion D can be changed by moving the light shielding plate 41 of the light beam shaping unit 40 forward and backward using the movement operation unit 42.
For this reason, the relative spectral reflectance measurement of the measurement surface 7a of the sample 7 to be measured can be performed in substantially the same manner as in the first embodiment.
In this measurement, the plurality of light shielding plates 41 arranged on the outer periphery of the opening 21a are selectively advanced and retracted by operation of the moving operation unit 42 to be reflected from the back surface and reach the opening 10b of the incident aperture stop 10a. A part of the measurement light beam can be shielded.
For this reason, even when the back surface 7b is inclined with respect to the measurement surface 7a of the sample 7 to be measured, the measurement accuracy can be improved by reducing the influence of the back surface reflection.
In the present embodiment, the amount of light shielded by the light shielding plate 41 can be set according to the state of incidence of incident light flux into the opening 10b. Since it does not need to be reduced, it is possible to improve the S / N ratio of measurement compared to the case where light is uniformly shielded.

  In the description of each of the above embodiments, the example in which the photometric device measures the relative spectral reflectance of the measurement target surface has been described. However, as can be easily understood from the above description, the influence of back surface reflection is Removed when measuring reflectance. Therefore, the photometric device may be a device that measures spectral reflection intensity (or light quantity or luminous intensity).

In the description of the third embodiment, the maximum advancing position of the light shielding plate 41 has been described as an example of a configuration that covers about 1/3 of the opening 21a, but the maximum advancing position of the light shielding plate 41 is an opening. It can be set as appropriate depending on how the back surface reflected light that can enter 10b is generated. For example, it may cover more than 1/3 of the opening 21a or less.
Further, for example, it is possible to hold the light shielding plates 41 so that they can advance and retract independently of each other. In this case, since a wider range can be covered by the two or more light shielding plates 41, even when the back-surface reflected light appears at various positions on the opening 10b, the incident to the opening 10b is more reliably performed. Can be prevented.

In the description of the third embodiment, an example in which four rectangular light shielding plates 41 are used has been described. However, this is an example, and the number and shape of the light shielding plates to be moved forward and backward are the same. It is not limited to. For example, the configuration may be one to three, or five or more. In addition to the rectangular shape, the shape of the light shielding plate can be, for example, an arc shape, a sector shape, a trapezoidal shape, or any other shape.
For example, as an example of using one light shielding plate, there is an example of a configuration in which an annular light shielding plate having an inner diameter larger than the outer diameter of the opening 21a is advanced and retracted in an arbitrary direction toward the center of the opening 21a. Can do.

  In the description of each of the above embodiments, the example in which the back surface reflected light is not incident on the photometry unit at all by the annular zone defect formed by the light beam shaping unit has been described. If so, it is permissible for some back-surface reflected light to enter the photometry unit.

  In the description of each of the above embodiments, an example in which the operator manually operates the light shielding position changing unit of the light beam shaping unit has been described. However, the light shielding position changing unit may be, for example, the light shielding member 22 or the diaphragm member 31. It is good also as a structure provided with the moving mechanism which can be motively driven by a motor etc. in order to rotate this and to move the light-shielding plate 41 forward and backward.

  In addition, all the components described in the above embodiments can be implemented by being appropriately combined or deleted within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Light source 2 Illumination lens 4 Collimator lens 5 Half mirror 6 Objective lens (1st condensing optical system)
7 Measurement Sample 7a Measurement Surfaces 7b, 7b ', 70b Back Surface 8 Imaging Lens 9 Imaging Optical System (Second Condensing Optical System)
10 Spectrometer (photometry part)
10a Entrance aperture stop (aperture stop)
10b Opening (opening)
14 Observation optical system (observation part)
14c Reference line 16 Measurement control part 20, 30, 40 Light beam shaping part 21 Ring zone aperture stop 21a Opening part (ring zone-shaped opening)
22 light shielding members 24 and 42 moving operation unit (light shielding position changing unit, light shielding member moving unit)
31 Diaphragm member 31a Opening portion (opening shape in which a light shielding region is formed in a part of the ring-shaped pattern in the circumferential direction)
31b Shading part (shading area)
33 Moving operation part (light-shielding position changing part)
41, 41A, 41B, 41C, 41D Light shielding plate (light shielding member)
50, 51, 52 Photometric device 70 Reference measurement sample (measurement sample)
70a Reference measurement surface (surface to be measured)
D, d, d ″ annular zone defect F incident light flux I ₀ , I ₁ image planes L ₀ , L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , L ₆ , L ₁₅ , L ₁₅ ′, L ₁₆ , L ₁₆ 'Measuring beam O Measurement reference axis

Claims (4)

A light source;
A light beam shaping unit capable of shaping a light beam emitted from the light source into a measurement light beam having a cross-sectional shape in which a ring-shaped defect portion is formed in a part of the circumferential direction of the ring-shaped pattern in a cross section orthogonal to the optical axis;
A light shielding position changing portion for changing the formation position of the annular zone defect portion;
A first condensing optical system for condensing the measurement light beam on a measurement surface of a sample to be measured;
A second condensing optical system for condensing a reflected light beam reflected by the sample to be measured among the measurement light beam;
An aperture stop disposed in an optically conjugate positional relationship with the surface to be measured across the second focusing optical system;
A metering unit for metering the luminous flux that has passed through the aperture stop;
An observation unit capable of observing an image projected by the second condensing optical system on an image plane optically conjugate with the surface to be measured by the second condensing optical system;
A photometric device. The light beam shaping unit
An annular aperture stop in which an annular aperture is formed;
A light-shielding member provided so as to be movable with respect to the aperture, and shielding a part of the aperture of the annular aperture stop to form the annular defect portion of the measurement light beam,
The light shielding position changing unit
The photometric device according to claim 1, further comprising a light shielding member moving unit that holds the light shielding member so as to be movable with respect to the opening of the annular aperture stop. The shading member moving part is
The photometric device according to claim 2, wherein the light shielding member is rotationally moved along a circumferential direction of the opening. The light beam shaping unit
A diaphragm member having an opening shape in which a light shielding region is formed in a part of the ring-shaped pattern in the circumferential direction,
The light shielding position changing unit
The photometric device according to claim 1, wherein the aperture member is rotationally moved in a circumferential direction of the annular pattern.

Images