WO1997038341A1 - Dispositif optique confocal - Google Patents

Dispositif optique confocal Download PDF

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Publication number
WO1997038341A1
WO1997038341A1 PCT/JP1997/001192 JP9701192W WO9738341A1 WO 1997038341 A1 WO1997038341 A1 WO 1997038341A1 JP 9701192 W JP9701192 W JP 9701192W WO 9738341 A1 WO9738341 A1 WO 9738341A1
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WO
WIPO (PCT)
Prior art keywords
light
array
pinhole
objective lens
receiving
Prior art date
Application number
PCT/JP1997/001192
Other languages
English (en)
Japanese (ja)
Inventor
Kiyonori Matsuno
Hideyuki Wakai
Toru Suzuki
Manabu Ando
Eri Suda
Original Assignee
Komatsu Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Komatsu Ltd. filed Critical Komatsu Ltd.
Publication of WO1997038341A1 publication Critical patent/WO1997038341A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/0004—Microscopes specially adapted for specific applications
    • G02B21/002—Scanning microscopes
    • G02B21/0024—Confocal scanning microscopes (CSOMs) or confocal "macroscopes"; Accessories which are not restricted to use with CSOMs, e.g. sample holders
    • G02B21/0036—Scanning details, e.g. scanning stages
    • G02B21/004—Scanning details, e.g. scanning stages fixed arrays, e.g. switchable aperture arrays
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
    • G01B11/306—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces for measuring evenness

Definitions

  • the present invention relates to a confocal optical device applied to a three-dimensional shape measuring device for measuring a three-dimensional shape of an object, and more particularly to an improvement in consideration of aberration and distortion of a lens used in the confocal optical device.
  • Fig. 17 shows its configuration.
  • light 1118 emitted from the light source 110 is shaped into parallel light by the lens 111, and a part thereof is emitted from the pinhole 112 as point light.
  • the light transmitted through the beam splitter 1 13 is condensed by an objective lens 114 constituting a telecentric system consisting of a lens 114a and a lens 114b, and a point source light is projected onto the object to be measured 115. Projected as
  • this projected light 1 18 is focused (focused) on the surface of the measured object 1 15, the reflected light 1 19 will be reflected on the surface of the measured object 1 15 After passing through the objective lens 114 along the same path as above, it reaches the beam splitter 113. Then, a part of the light is reflected and focused on the light receiving pinhole 1 16 located at a position conjugate with the light emitting pinhole 112.
  • a photodetector 117 is provided behind the light receiving pinhole 116, and detects the intensity of light passing through the pinhole 116 by the photodetector 117.
  • the path of the reflected light is indicated by the dotted line 130. That is, the reflected light 130 is focused in front of the pinhole 116, and when it reaches the pinhole 116, the light is greatly blurred. As a result, in this case, the amount of light entering the photodetector 117 is greatly reduced as compared with the time of focusing. This is the same when the object to be measured 1 15 is shifted from the focal point to the near side.
  • Fig. 18 shows the change in the amount of light received by the photodetector 117 when the object to be measured 1 15 is moved in the Z direction. That is, in a confocal optical system, An extremely strong signal can be observed only when the focus of the objective lens 114 matches the surface of the object 115 to be measured. Therefore, when the output of the photodetector 1 17 is sampled while displacing the object 1 1 5 or the objective lens 1 1 4 in the Z direction, and the output of the photo detector 1 17 becomes maximum, Can be detected as the surface position of the measured object 15. Therefore, the surface shape of the object 115 can be measured by repeating the scanning in the Z direction while scanning the object in the X and Y directions.
  • Figure 19 shows the confocal optical system expanded in two dimensions.
  • the light emitting pinhole array 120 is an array of pinholes 121 arranged in a square lattice, as shown in FIG. 0 As shown, the pinholes 123 are arranged in a square lattice, and the photodetector array 124 is a square grid, as shown in Fig. 20 ⁇ ). It is arranged in a shape.
  • light 126 represents an optical path of one of the point light source arrays emitted from the light projecting pinhole array 120. That is, even in the confocal point optical system shown in FIG. 19, the light emitted from the point light source 120 is reflected by the object to be measured 115, reaches the light receiving pinhole array 122, and has a photodetector. Detected in array 124. In the confocal optical system shown in FIG. 19, the light emitted from the point light source 120 is reflected by the object to be measured 115, reaches the light receiving pinhole array 122, and has a photodetector. Detected in array 124. In the confocal optical system shown in FIG.
  • the object to be measured 1 15 is mounted on a moving stage 127, and while moving the moving stage 127 in the Z direction, the photodetector array 1
  • the outputs of the individual photodetectors in step 4 are sampled separately, and the position in the Z direction when the output of each photodetector is maximized is detected as the surface position of the object 115.
  • the point light source is projected from the two-dimensional light projection array onto the object to be measured, and the reflected light is detected by using the confocal effect of the light receiving array.
  • the off-axis aberration of the objective lens 114 is not taken into account, and the two-dimensional arrangement shown in FIG. In a confocal optical device having an array of light emitting and receiving systems, the following various problems occur.
  • the first is a phenomenon in which an image is blurred when light is projected onto a plane, and is called an aberration in the following description.
  • the aberration includes, for example, chromatic aberration, coma aberration, spherical aberration, astigmatism, and the like.
  • the image is not blurred but its shape is distorted. This is called distortion.
  • the same lens is arranged face-to-face and light is transmitted, aberration is amplified, but distortion is almost canceled.
  • the point light source emitted from the light projecting pinhole array 120 is projected onto the object 115 by the objective lens 114.
  • the lens 114 since the lens 114 always has an aberration, the point light source light is not projected while maintaining the same size, and is usually blurred and the spot diameter becomes large.
  • the spot light does not always maintain a circular shape, but may take an asymmetrical shape such as a fan shape.
  • the light emitting pinhole array 120, the measured object surface 1 15 and the light receiving pinhole surface 122 In this case, for the sake of simplicity, the magnification of the objective lens 114 is 1: 1 (1 ⁇ ).
  • the spot light on the surface of the object to be measured 115 and the light receiving pinhole surface 122 has the diameter at a plurality of specific positions as shown in FIG. It has become big.
  • the spot light on the surface of the object to be measured 115 and the light receiving pinhole surface 122 has a fan-shaped peripheral portion as shown in FIG. It has become.
  • the size and shape of the spot light on the surface of the object to be measured 1 15 and the light receiving pinhole 1 2 2 are generated due to the aberration of the objective lens 114.
  • the pinhole diameters and the shapes of the light receiving arrays 122 are all formed in the same manner. For this reason, in the prior art, depending on the pinhole positions of the light receiving pinholes 122, a considerable percentage of light is kicked by the light blocking portion of the pinhole array and does not enter the photodetector array 124. there were. In other words, where the aberration is large, the detection signal at the time of focusing is weakened, making it indistinguishable from that at the time of out-of-focus. .
  • the amount of light detected is weak. There is a problem that can not be. Conversely, if the light amount of the light source is determined so that sufficient light can be obtained in the peripheral area, there is a risk that the output of the light detector in the central area may overflow.
  • the peripheral part tends to be more blurred due to aberrations than the central part.
  • the light intensity of the projected part approximates a Gaussian distribution.
  • the stronger the light is projected toward the center the more the above tendency becomes more remarkable.
  • This distortion phenomenon is caused by the fact that when an array of square lattices as shown in Fig. 24 is projected by a lens, for example, the contour does not become a square lattice, and the barrel shape shown in Fig. 24 or the shape shown in Fig. 24 fc A phenomenon that turns into a wound type.
  • each small circle SP in Fig. 25 (“represents the spot light of the light emitting pinhole array 120, and Fig. 25 (3 ⁇ 4) shows the spot light arrangement on the surface 1 15 of the measured object.
  • Fig. 25c shows the spot light arrangement on the light-receiving pinhole surface 122.
  • the lines connecting the spot lights show the distortion in an easy-to-understand manner. For This is a virtual line, which is the same in the following figures.
  • the point light source array of the light emitting array 120 has a square lattice shape
  • distortion occurs when passing through the lens 114, and for example, on the surface of the object 115, FIG. 25 (b) As shown in Fig. 5, it is observed as a wound type arrangement.
  • these lights are reflected and projected on the light receiving pinhole array surface 122, the distortion is canceled by the lens 114, and the spot light arrangement is as shown in FIG. Return to the square lattice arrangement.
  • the pitch of the spot light arrangement is coarser at the periphery than at the center. . Therefore, when the surface shape, that is, the height of the object to be measured 115 is measured using such a spot light array, the peripheral part is measured with a coarser pitch than the central part. As a result, the measurement pitch is not constant, and the measurement accuracy is reduced. Therefore, in order to accurately measure a three-dimensional shape using such measurement data, it is necessary to perform data interpolation using a computer or the like, which requires extra time and equipment.
  • the present invention has been made in view of such circumstances, and can accurately and accurately measure aberrations and distortion without increasing the performance of a lens used in a confocal optical system. It is an object to provide a confocal optical device.
  • a point light source array for generating light by a plurality of arranged point light sources, an objective lens for condensing light generated from the point light source array on an inspection surface
  • the inspection A confocal optical device comprising: a light receiving array in which a plurality of light receiving units are arranged to receive light reflected by an object to be measured on a surface via the objective lens; The size of each light receiving section of the light receiving array is changed according to the aberration of the objective lens.
  • the size of each light receiving section of the light receiving array is changed according to the aberration of the objective lens. For example, in a light-receiving array, if the spot diameter of light in the peripheral part is larger than the spot diameter of light in the central part due to lens aberration, the size of the light-receiving part in the central part should be larger than that in the peripheral part. Enlarge.
  • a point light source array that generates light by a plurality of arranged point light sources, an objective lens that condenses light generated from the point light source array on an inspection surface
  • a confocal optical device comprising: a light receiving array in which a plurality of light receiving units are arranged to receive light reflected by an object to be measured on a surface via the objective lens; The shape of each light receiving section of the light receiving array is changed.
  • the shape of each light receiving section of the light receiving array is changed according to the aberration of the objective lens.
  • a point light source array for generating light from a plurality of arranged point light sources, an objective lens for condensing light generated from the point light source array on an inspection surface, and the inspection
  • a confocal optical device comprising: a light receiving array in which a plurality of light receiving units are arranged to receive light reflected by an object to be measured on the surface via the objective lens; The arrangement of each point light source of the point light source array is distorted corresponding to the distortion of the objective lens so that the arrangement has an equal pitch without distortion.
  • the arrangement of the point light sources of the point light source array is distorted corresponding to the distortion of the objective lens so that the arrangement of the light spots on the inspection surface has an equal pitch without distortion.
  • the distortion of the objective lens is a pincushion type
  • the arrangement of each point light source in the point light source array is a ⁇ shape opposite thereto.
  • a point light source array for generating light by a plurality of arranged point light sources, an objective lens for condensing light generated from the point light source array on an inspection surface, and the inspection
  • a confocal optical device comprising a light receiving array in which a plurality of light receiving sections for receiving light reflected by an object to be measured on a surface via the objective lens is provided. The arrangement of each light receiving portion of the light receiving array is distorted so as to correspond to the arrangement of light spots incident on the light receiving array.
  • the arrangement of each light receiving section of the light receiving array is distorted so as to correspond to the arrangement of light spots incident on the light receiving array.
  • the arrangement of each light receiving section of the light receiving end ray is of the pin winding type corresponding to this.
  • a point light source array for generating light by a plurality of arranged point light sources, an objective lens for condensing light generated from the point light source array on an inspection surface, and the inspection
  • a light-receiving pinhole array in which light reflected by an object to be measured on a surface is condensed by the objective lens, a plurality of pinholes are arranged, and the light passes through each pinhole of the light-receiving pinhole array.
  • a photodetector array in which a plurality of photodetectors for receiving the received light are arranged; and a relay lens for guiding light passing through each of the light receiving pinholes to each of the photodetectors in the photodetector array.
  • a confocal optical device comprising: an arrangement of each point light source of the point light source array corresponding to the distortion of the objective lens so that an arrangement of light spots on the inspection surface has an equal pitch without distortion.
  • the distortion In addition, the arrangement of each pinhole of the light-receiving pinhole array is distorted so as to correspond to the arrangement of light spots incident on the light-receiving pinhole array, and the distortion between the relay lens and the objective lens is further reduced. They are set the same.
  • the objectives are arranged such that the arrangement of the light spots on the inspection surface is equal pitch without distortion.
  • the arrangement of each point light source of the point light source array is distorted corresponding to the distortion of the lens.
  • the corresponding light-receiving pinhole on the inspection surface corresponding to Make sure that all light spots are incident.
  • the distortion between the relay lens and the objective lens is set to be the same so that light at an equal pitch without array distortion is incident on the photodetector array.
  • a pinhole device in which a plurality of pinholes are arranged A ray and an object to be measured arranged on a predetermined inspection surface
  • An objective lens for guiding light so as to set the inspection surface position to a second light collection position, a light source means for inputting light to the pinhole array, and the pinhole array.
  • a light detector array provided on a side opposite to the objective lens and having a plurality of light detectors for detecting light passing through each pinhole of the pinhole array; Is projected on the object to be measured via the pinhole array and the objective lens, and the light reflected by the object to be measured is reflected on the photodetector array via the objective lens and the pinhole array.
  • a confocal optical device configured to enter each photodetector
  • the arrangement of the pinholes in the pinhole array is distorted corresponding to the distortion of the objective lens so that the arrangement of the light spots on the inspection surface has an equal pitch without distortion.
  • the present invention provides a confocal optical device having a configuration in which a pinhole array for projecting light and a pinhole array for receiving light are shared by a single pinhole array.
  • the arrangement of the pinholes of the pinhole array is distorted in accordance with the distortion of the objective lens so that there is no uniform pitch. That is, in the present invention, the pinhole array for light emission and the pinhole array for light reception are shared by one pinhole array, and the diameter of the pinhole cannot be changed. I try to remove only the negative effects of distortion.
  • a point light source array that generates light by a plurality of arranged point light sources, an objective lens that condenses light generated from the point light source array on an inspection surface, and the inspection
  • a confocal optical device including a light receiving array in which a plurality of light receiving units that receive light reflected by an object to be measured on a surface via the objective lens are arranged in accordance with an aberration of the objective lens. The size of each point light source in the point light source array is changed.
  • the size of each point light source of the point light source array is changed according to the aberration of the objective lens, so that light spots having the same size are arranged on the inspection surface.
  • FIG. 1 is a plan view showing the arrangement and light spot patterns at various points in the first embodiment of the present invention.
  • FIG. 2 is a diagram showing a confocal optical system to which the first embodiment of the present invention is applied.
  • FIG. 3 is a diagram showing a confocal optical system to which a second embodiment of the present invention is applied.
  • FIG. 4 is a diagram showing a confocal optical system to which a third embodiment of the present invention is applied.
  • FIG. 5 is a diagram showing a confocal optical system to which a fourth embodiment of the present invention is applied.
  • FIG. 6 is a plan view showing the arrangement and light spot patterns at various points in the fourth embodiment of the present invention.
  • FIG. 7 A plan view showing other arrangements and light spot patterns at various points in the fourth embodiment of the present invention.
  • FIG. 8 is a diagram showing a confocal optical system to which a fifth embodiment of the present invention is applied.
  • FIG. 9 Arrangement diagram of the optical system during hologram exposure according to the fifth embodiment.
  • FIG. 10 A diagram showing a confocal optical system to which a sixth embodiment of the present invention is applied.
  • FIG. 11 A plan view showing the arrangement and light spot patterns at various points in the sixth embodiment of the present invention.
  • FIG. 12 A diagram for explaining a seventh embodiment of the present invention.
  • FIG. 13 A diagram for explaining a seventh embodiment of the present invention.
  • FIG. 14 A diagram for explaining an eighth embodiment of the present invention.
  • FIG. 15 A diagram for explaining the ninth embodiment of the present invention.
  • FIG. 16 A diagram for explaining the tenth embodiment of the present invention.
  • Figure 17 Diagram showing conventional technology.
  • Fig. 18 Diagram showing the relationship between the position of the measured object in the height direction and the amount of received light.
  • Figure 19 Diagram showing conventional technology.
  • FIG. 20 is a plan view showing the arrangement of various parts of the prior art in FIG.
  • Fig. 21 Diagram explaining conventional problems.
  • Figure 22 Diagram explaining conventional problems.
  • Figure 23 Diagram explaining conventional problems.
  • Figure 24 Diagram explaining conventional problems.
  • Figure 25 Diagram explaining conventional problems. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 2 shows a configuration example of a confocal optical device to which the first embodiment of the present invention is applied.
  • FIG. 2 light from a light source 1 is converted into parallel light via a lens 2 and is incident on a light-emitting pinhole array 3.
  • the light projecting pinhole array 3 has the pinholes ph arranged in a barrel shape.
  • the light passing through the light emitting pinhole array 3 passes through the beam splitter 4, is condensed by an objective lens 5 constituting a telecentric system, and is projected on an object 6 to be measured on a moving stage 7.
  • the moving stage 7 is configured to be movable in X—Y—Z—0 (rotation) directions. The movement in the X-Y direction is used when the visual field on the measured object 6 projected by the light projecting pinhole array 3 is moved.
  • the magnification of the objective lens 5 is set to 1: 1 (1: 1) for simplification.
  • the objective lens 5 has a pincushion type. It shall have distortion.
  • the blur of the light spot due to the aberration of the lens 5 is larger in the peripheral part than in the central part.
  • the light reflected by the measured object 6 is condensed by the lens 5, further reflected by the beam splitter 4, and forms an image on the light receiving pinhole array 8.
  • the light-receiving pinhole array 8 has an array of pin holes ph having the same ⁇ shape as the light-emitting pinhole array 3, and its pinhole diameter is smaller at the periphery than at the center. The larger one has a larger diameter.
  • each photodetector 10 is provided, and as shown in the figure, a photodetector array 9 arranged in a square matrix is provided. The light intensity that has passed through each pinhole ph of the light-receiving pinhole array 8 is detected.
  • the light projecting pinhole array 3 is, as shown in FIG.
  • the diameter of each pinhole ph is the same, but the arrangement is distorted in a barrel shape.
  • the light receiving pinhole array 8 is configured such that the diameter of each pinhole is larger at the periphery than at the center, and the arrangement is distorted into a beat shape.
  • each point light source emitted from the light-emitting pinhole array 3 having the barrel-shaped pinhole array passes through the objective lens 5 having a pincushion type distortion.
  • the barrel-shaped arrangement distortion is cancelled, and as shown in FIG. 1), the object 6 is irradiated in a square lattice shape. Therefore, in this embodiment, the spot light pattern on the measured object 6 has the same pitch in all regions, and it is not necessary to perform the interpolation calculation processing of the measurement data as in the related art.
  • the spot light pattern on the measured object 6 has a larger spot light diameter toward the periphery due to the aberration of the objective lens 5.
  • the light reflected on the surface of the object 6 to be measured is reflected by the beam splitter 4 and projected on the light receiving pinhole array 8, and the pattern of the projected light is as shown in FIG. Become. That is, the arrangement of the spot light pattern on the light receiving pinhole array 8 is reciprocated through the objective lens 5 so that the distortion is canceled and the arrangement becomes almost the same barrel shape as the light emitting pinhole array 3. The aberration is further doubled by reciprocating through the objective lens 5, and the spot diameter is further increased in the peripheral portion. Note that the spot light pattern shown in FIG. 1 is obtained when the Z position on the surface of the object 6 to be measured coincides with the focal point of the objective lens 5 and is in focus.
  • the light receiving pinhole array 8 has an arrangement of barrel-shaped pinholes ph, and the pinhole diameter is set to be larger at the peripheral portion than at the central portion.
  • the pinhole arrangement and the pinhole diameter at this time are set so as to match those of the spot light pattern on the light receiving pinhole array 8 shown in FIG.
  • the light-receiving pinhole array 8 even if spot light projected on the light-receiving pinhole array 8 has a variation in diameter and distortion due to off-axis aberration of the objective lens 5, When in focus, all light reflected on the surface of the It is possible to obtain a perfect confocal effect that passes through and blocks a part of the light reflected on the surface of the object 6 when out of focus.
  • the photodetector array 9 may adopt a barrel-shaped arrangement corresponding to the arrangement of the light-receiving pinhole array 8, but it is expensive, so in this embodiment, as shown in FIG. A commercially available CCD array in which the devices 10 are arranged in a square lattice is used.
  • Figure 1 shows a state in which the photodetector array 9 and the spot light pattern on the light receiving pinhole array 8 are superimposed.
  • each photodetector 10 has: All the light passing through the corresponding light receiving pinhole can be received, and the light passing through the adjacent light receiving pinhole is not received. Crosstalk between them can be suppressed, and performance such as resolution of the confocal optical system can be improved.
  • the effects of aberration and distortion are both so large that they cannot be ignored.
  • the light emitting pinhole array 3 has a square lattice array having the same pinhole diameter as shown in FIG.
  • the light receiving pinhole array 8 may be a square lattice array having a larger pinhole diameter at the periphery than at the center, as shown in FIG.
  • the pinhole diameter of the light receiving pinhole array 8 correspondingly goes to the peripheral portion. It is good to set it as large as possible.
  • FIG. 3 shows a second embodiment of the present invention.
  • the point light source array is realized by the light source 1, the lens 2, and the light projecting pinhole array 3, but in the second embodiment, the light emitting elements 1 and 2 are arranged two-dimensionally.
  • the array 13 realizes a point light source array.
  • Other components are the same as those in the first embodiment, and a duplicate description will be omitted. That is, in this embodiment, as shown in FIG. 3), the light emitting elements 12 are arranged by arranging the light emitting elements 12 of the same size in a rectangular shape.
  • the light-receiving pinhole array 8 has an arrangement of barrel-shaped binholes ph, as shown in the figure, and the pinhole diameter is larger at the periphery than at the center. It has a large diameter.
  • FIG. 4 shows a third embodiment of the present invention.
  • each light detector 15 is a pin.
  • the photodetector array 14 is well known, for example, from Japanese Patent Application Laid-Open No. Hei 4-26959. However, this publication does not mention anything about the arrangement of the photodetectors and the size of the light receiving area.
  • the light-projecting pinhole array 3 is formed in a barrel-shaped array
  • the photodetector array 14 is formed as a CCD array having a crepe shape as shown in FIG. (Light receiving area) is set to be larger in the peripheral part than in the central part.
  • FIG. 5 shows a fourth embodiment of the present invention.
  • a relay lens 16 is arranged between the light receiving pinhole array 8 and the photodetector array 9.
  • Such a configuration may be used, for example, when the structure of the photodetector array 9 does not allow the detector array 9 and the light receiving pinhole array 8 to be in close contact with each other. This is used when the pinhole pitch of the pinhole array 8 cannot be matched.
  • the newly provided relay lens 16 also has aberration and distortion.
  • the distortion of the relay lens 16 is ⁇ -shaped distortion
  • the distortion of the objective lens 5 is of the pincushion type, as in the previous embodiments.
  • the distortion and aberration of the objective lens 5 are assumed to be the same as those of the first embodiment
  • the light emitting pinhole array 3 and the light receiving pinhole array 8 are the same as those of the first embodiment.
  • the thing is adopted. That is, in the light emitting pinhole array 3, as shown in FIG. 6f, the diameter of each pinhole ph is the same, but the arrangement is distorted into a barrel shape. Further, as shown in FIG. If, the light receiving pinhole array 8 is configured such that the diameter of each pinhole is larger at the periphery than at the center, and the arrangement is distorted into a ⁇ shape. .
  • the birch-shaped point light source array light emitted from the light-emitting pinhole array 3 passes through the objective lens 5 so that the distortion is cancelled, resulting in a square lattice array as shown in Fig. 6. Is projected on the surface of the object 6. However, as shown in FIG. 6, the spot light pattern on the measured object 6 has a larger spot light diameter in the peripheral portion due to the influence of the difference of the objective lens 5.
  • the light reflected on the surface of the measured object 6 is reflected by the beam splitter 4 and projected on the light receiving pinhole array 8.
  • the pattern of the projected light is shown in FIG.
  • the reciprocation of the objective lens 5 cancels the distortion, and the shape becomes almost the same as that of the light emitting pinhole array 3.
  • the aberration is further doubled by reciprocating through the objective lens 5, and the spot diameter is further increased toward the periphery. The above is the same as in the first embodiment.
  • FIG. 6fe shows a state where the photodetector array 9 and the spot light pattern on the photodetector array 9 are superimposed.
  • the photodetector array 9 can detect all the light that each photodetector 10 has passed through the light-receiving pinhole array 8 and not receive light that has passed through other pinholes. Thus, it is necessary to optimally set the pitch, arrangement, shape, light receiving area, aperture ratio, and the like.
  • Figure 7 shows the pinhole array of the light-emitting pinhole array 3, the light-emitting pattern on the measured object 6, the light pattern on the light-receiving pinhole array 8, and the pinhole array of the light-receiving pinhole array 8. These are the same as in FIG.
  • the distortion of the relay lens 16 is the same as that of the objective lens 5
  • the light passes through the relay lens 16 having the distortion of the thread type, so that the birch is formed on the light receiving pinhole array 8.
  • the arrangement distortion of the light pattern having the shape is canceled, and the light is irradiated on the photodetector array 9 in a square lattice shape as shown in FIG.
  • FIG. 7 shows the photodetector array 9 used in this case.
  • FIG. 7 ( ⁇ ) shows a state where the photodetector array 9 and the spot light pattern on the photodetector array 9 are superimposed.
  • a square lattice-shaped spot light is irradiated on the photodetector array 9, so that there is no need to use a large light detection area as in the case of FIG.
  • a photodetector 10 having a small surface ridge can be employed.
  • the relay lens 16 when the relay lens 16 is used, if the distortion of the relay lens 16 is the same as the distortion of the objective lens 5, a square lattice-like shape is formed on the photodetector array 9.
  • a spot light can be irradiated, and an inexpensive CCD that is usually commercially available as a photodetector array can be used.
  • FIG. 8 shows a fifth embodiment of the present invention.
  • a hologram 24 is used in place of the light projecting pinhole array 3 used in the previous embodiment, and this hologram 24 is equivalent to the point light source array light emitted from the light projecting pinhole array 3. I try to reproduce the light.
  • reference numeral 20 denotes a photodetector array
  • 21 denotes a relay lens
  • 22 denotes a light receiving pinhole array
  • 23 denotes an objective lens
  • 24 denotes a hologram
  • 25 denotes a reference beam
  • 26 denotes an object to be measured
  • Reference numeral 27 denotes a moving stage.
  • the hologram 24 is used as a means for generating point light source light. To play.
  • the reference light when the reference light is incident on the hologram 24, light equivalent to the presence of a point light source at each pinhole of the light receiving pinhole array 22 is reproduced by the hologram 24. Then, the reproduced light is imaged on the measured object 26 on the moving stage 27 by the objective lens 23. The light reflected by the object to be measured 26 forms an image at each pinhole position of the light receiving pinhole array 22 via the lens 23 and the hologram 24, and then the light is detected via the relay lens 21. Incident on each of the 9 photodetectors in the detector array.
  • the objective lens 23 and the relay lens 21 have the same pincushion type distortion characteristics.
  • FIG. 9 shows a configuration for exposing the hologram 20.
  • the same objective lens 23 as that of FIG. 8 is used, and the objective lens 23 is arranged in the same positional relationship as that of FIG.
  • the exposure pinhole 37 is also arranged in the same positional relationship as the light receiving pinhole 22 in FIG.
  • light emitted from a laser 30 becomes parallel light having a large diameter by a collimator lens 31, and is split by a beam splitter 32.
  • the light 33 traveling straight is turned by the mirror 34, passes through the pinhole array 37 for exposure, becomes a point light source light, and then becomes object light to the hologram 24 via the objective lens 23.
  • the light 35 reflected by the beam splitter 32 is further reflected by the mirror 36 and is incident on the hologram 24 as reference light.
  • the hologram 24 has a point light source at each pinhole position of the exposure pinhole array 37, and a light equivalent to the presence of the lens 23 (exactly, only the upper lens). Will be exposed.
  • the exposure pinhole array 37 uses the barrel-shaped pinhole array as shown in FIG. Therefore, in FIG. 9, the zen-shaped point light source array light emitted from the exposure pinhole array 37 passes through the objective lens 23 having a pincushion type distortion characteristic, and its distortion is reduced. Canceled, as shown in the previous Figure 7 (3 ⁇ 4) The light is projected on the inspection surface 26 in a square lattice shape. Since the hologram 24 exposes and records this property as it is, the same light is projected onto the inspection surface during reproduction.
  • the light pattern on the light receiving pinhole array 22 is as shown in FIG. That is, when the light reciprocates through the objective lens 23, the distortion is canceled, and a barrel shape similar to that of the exposure pinhole array 3 shown in FIG. 7 is obtained. However, the effect of aberration is doubled by reciprocating through the objective lens 5, and the spot diameter is further increased in the peripheral portion.
  • the light-receiving pinhole array 22 of FIG. 8 should have a pinhole arrangement and a pinhole diameter that matches the light pattern on the pinhole array 22 shown in FIG. That is, the pinhole pattern of the pinhole array 22 has a barrel-shaped arrangement as shown in FIG. 7 (shown above), and the pinhole diameter is incident on the pinhole array 22. As with the light pattern, the diameter of the peripheral portion is set to be larger than that of the central portion, that is, when the pinhole array for exposure 37 and the light receiving pinhole array 22 are compared. Although the arrangement positions of these pinholes are the same, the diameter of the pinhole is larger in the light receiving pinhole array 22.
  • the light passing through the light-receiving pinhole array 22 having the ⁇ -shaped pinhole array receives the pincushion-type distortion by passing through the relay lens 21, whereby the light distortion is reduced.
  • the light is canceled out and becomes a square lattice spot light as shown in Fig. 7fe) and is incident on the photodetector array 20. Therefore, the photodetector array 20 in this case can adopt a square lattice-like photodetector array as shown in FIG. 7f), and the light receiving area of each photodetector is also large. There is no need to use such a large one.
  • a confocal optical device that minimizes the effects of lens aberration and distortion is realized. can do.
  • a transmission type hologram is used as a hologram type, but it is needless to say that another type such as a reflection type can be applied.
  • FIG. 10 shows a sixth embodiment of the present invention.
  • the functions of the light emitting pinhole array and the light receiving pinhole array are shared by one pinhole array 41.
  • the pinhole array shape of No. 1 is changed in consideration of distortion by the lens. That is, in this embodiment, since the light emitting and receiving pinhole array 41 is shared, the pinhole diameter cannot be enlarged in consideration of the aberration of the lens, and only the pinhole array shape is zen-shaped. Is set to.
  • the light from the light source 1 becomes parallel light through the lens 2 and is reflected by the beam splitter 4, and then enters the light emitting and receiving pin hole 41 through the relay lens 40 having a pincushion type distortion action.
  • the light emitting and receiving pinhole array 41 has pinholes having the same diameter arranged in a barrel shape.
  • the light that has passed through the barrel-shaped light receiving / receiving pinhole array 3 is condensed by an objective lens 5 having a pincushion type distortion action, and is projected onto an object 6 to be measured on a moving stage 7.
  • the spot light array projected on the object 6 to be measured undergoes a pincushion distortion by the objective lens 5, and becomes a square lattice as shown in FIG. 11).
  • Each light reflected by the measured object 6 passes through the lens 5 again to cancel the pincushion-type distortion and form a barrel-type distortion arrangement as shown in FIG. Then, the light is incident on each pinhole of the light emitting and receiving pinhole array 41 having a barrel-shaped distortion arrangement.
  • the light that has passed through the light emitting / receiving pinhole array 41 is subjected to pincushion distortion by the relay lens 40, and becomes light having a square lattice arrangement as shown in FIG. 1If, via the beam splitter 4. Incident on the photodetector array 9.
  • the photodetector array As shown in FIG. 1 lfe, 9, the photodetectors 10 having a relatively small light receiving area are arranged in a square grid, so that the incident light can be reliably received.
  • FIG. 11 is a superposition of FIG. 11 (1> and fe).
  • the arrangement of light on the surface of the object is a square lattice, the accuracy of measurement is improved.
  • the arrangement of the light incident on the photodetector array 9 also has the same square lattice shape as the matrix arrangement of the photodetectors, which facilitates the alignment of the detector array.
  • a light-emitting array is composed of an LD array, and the output of the LD changes when reflected light from an object enters the LD.
  • the arrangement of the LD array may be distorted in accordance with the distortion of the objective lens.
  • the arrangement of the light-emitting pinhole array, the light-receiving pinhole array, and the photodetector array is shown as a square lattice having the same vertical and horizontal pitches. Arrays are most often arranged in the form of a square lattice. In addition, arranging the spot light array on the detection surface in the form of a square lattice is convenient for understanding the surface shape of an object.
  • FIG. 12 a rectangular arrangement having different vertical and horizontal pitches as shown in FIG. 12 may be employed, and a triangle arrangement which is a repetition of triangles as shown in FIG. 13 may be employed. It may be.
  • Figs. 12 and 13 (indicates the array of the light emitting array, (3 ⁇ 4) indicates the light array projected on the object to be measured, and fe) indicates the light array on the light receiving pinhole surface.
  • the pinhole arrangement of the light receiving pinholes is shown, and fe) shows the arrangement of the photodetector array.
  • the present invention can be applied not only to a two-dimensional array but also to a one-dimensional array. Even in the one-dimensional case, the diameter of the pinhole, the shape of the line connecting the pinholes, and the like may be changed according to the aberration and distortion of the lens used.
  • the aberration of the objective lens or the relay lens has a tendency that the blur tends to be small in the central portion and large in the peripheral portion.
  • Some lenses have a dazzle.
  • FIG. 14 there is a lens in which blurring due to aberration increases at a predetermined position q between a central portion and a peripheral portion.
  • (3 ⁇ 4) indicates the arrangement of the light emitting array, indicates the light array projected on the object to be measured
  • (3 ⁇ 4> indicates the light array on the light receiving pinhole surface
  • ⁇ ) Indicates the pinhole arrangement of the light receiving pinhole, and indicates the arrangement of the photodetector array.
  • the pinhole diameter of the light receiving pinhole array may be increased corresponding to the blurred position.
  • blur due to aberration not only changes in size but also in shape.
  • the spot light projected on the object has an egg shape.
  • the shape of each pinhole of the light receiving pinhole array is made oval in accordance with the aberration of the lens.
  • FIG. 16 shows a tenth embodiment of the present invention.
  • the light emitting pinhole array in order to cancel the adverse effect of the lens aberration on the confocal effect, is changed only in its pinhole arrangement without changing the diameter of each pinhole. For this reason, in the above embodiment, for example, the spot diameter of the light projected on the object differs between the central part and the peripheral part due to the aberration of the lens as shown in FIG.
  • the spot diameter of the light projected onto the object be as small as possible and uniform.
  • the diameter of the pinhole of the light emitting pinhole array is set to be larger at the center than at the periphery.
  • the confocal optical system shown in FIG. 2 it is assumed that the confocal optical system shown in FIG. 2 is used, and the objective lens 5 has an aberration in which the periphery of the lens surface is more blurred than the center. And Here, the distortion is ignored.
  • the central part is larger than the peripheral part, as shown in Fig. 16a).
  • the light emitted from the projection pinhole array 3 having the pinhole diameter is affected by the aberration of the lens 5 by passing through the lens 5, and when it reaches the object 6 to be measured, (As shown in 3 ⁇ 4J, the diameter of the spot light is almost the same in all regions.
  • the light reflected by the object to be measured passes through the lens 5 again, and is further affected by aberrations.
  • the diameter of the spot light is larger at the periphery than at the center.
  • the pinhole diameter of the light-receiving pinhole array 8 is correspondingly set to be larger at the periphery than at the center, as shown in FIG. 16f.
  • FIG. 16 fe shows the arrangement of the photodetectors of the photodetector array 9, and FIG. 16 is a superposition of FIG. 16.
  • each photodetector of the photodetector array 9 all light passing through the corresponding pinhole is incident on the photodetector, and light passing through other pinholes is prevented from entering the photodetector.
  • the array, light receiving area, etc. are set.
  • the pinhole diameter of the light emitting pinhole array is made larger in the central part than in the peripheral part, the diameter of each spot light projected on the object is uniform. Thus, the accuracy of measuring the three-dimensional shape of the object can be improved.
  • the effect of lens distortion is actually added, and accordingly, the pinhole arrangement of the light emitting pinhole array 3 and the light receiving pinhole array 8 is changed to a barrel type or a pincushion type. Should be set to.
  • a laser or the like can be considered in addition to a normal lamp.
  • the method of irradiating the light emitting array to the light is not limited to the collective irradiation, and there is, for example, a method of scanning a laser beam.
  • the effects of both aberration and distortion due to the lens can be canceled at once.
  • only one of the distortion and the aberration may cause a problem. In that case, only one of the two needs to be applied. For example, if the distortion of the lens is very small and the aberration is large, the pinhole array remains a square lattice, and the pinhole diameter is adjusted according to the aberration. Can be changed.
  • the point light source array is realized by arranging the light emitting elements or making the light source light incident on the light emitting pinhole array.
  • a point light source array can be created by using a micro-lens array in which the light from a light source is incident on the microphone array. That is, as the point light source array, any method may be used as long as a point light source can be substantially produced.
  • the array on the light receiving side may be composed of a pinhole array and a photodetector array, and each light receiving area has a small light receiving area approximately equal to that of the pinhole. It may be constituted only by a photodetector array in which detectors are arranged.
  • each light receiving portion of the light receiving array when referring to the size of each light receiving portion of the light receiving array, if the light receiving array is composed of a pinhole array and a detector array, it refers to the size of the pinhole. If is a detector array with a small light receiving area, it represents the size of the light receiving area of the detector itself.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Microscoopes, Condenser (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

Cette invention concerne un dispositif optique confocal doté d'une matrice de sources lumineuses ponctuelles, ladite matrice étant conçue pour générer de la lumière à partir d'une pluralité de sources lumineuses ponctuelles agencées dans ce but, une lentille d'objectif conçue pour focaliser la lumière générée par ladite matrice de sources lumineuses ponctuelles sur une surface de contrôle, et une matrice d'éléments récepteurs de lumière dans laquelle est disposée une pluralité d'éléments récepteurs de lumière conçus pour recevoir la lumière réfléchie par un objet à mesurer sur la surface de contrôle. On fait varier les tailles des éléments récepteurs de lumière en fonction des aberrations de l'objectif de telle sorte que ces aberrations et la distorsion peuvent être absorbées de manière sûre sans accroître l'efficacité des lentilles utilisées dans le système optique confocal et il est possible d'effectuer une mesure correcte et très précise.
PCT/JP1997/001192 1996-04-08 1997-04-08 Dispositif optique confocal WO1997038341A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP8/85570 1996-04-08
JP8557096A JPH09274139A (ja) 1996-04-08 1996-04-08 共焦点光学装置

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WO1997038341A1 true WO1997038341A1 (fr) 1997-10-16

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
CN110596720A (zh) * 2019-08-19 2019-12-20 深圳奥锐达科技有限公司 距离测量系统
US11054365B2 (en) 2016-02-23 2021-07-06 Shimadzu Corporation Microscopic analysis device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6863578B2 (ja) * 2017-04-19 2021-04-21 日本分光株式会社 赤外顕微鏡

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JPS63286752A (ja) * 1987-05-20 1988-11-24 Toshiba Mach Co Ltd パタ−ンの欠陥検査または寸法測定方法
US4806004A (en) * 1987-07-10 1989-02-21 California Institute Of Technology Scanning microscopy
US4845552A (en) * 1987-08-20 1989-07-04 Bruno Jaggi Quantitative light microscope using a solid state detector in the primary image plane
JPH01503493A (ja) * 1987-03-27 1989-11-22 ザ ボード オブ トラスティーズ オブ ザ リーランド スタンフォード ジュニア ユニバーシティ 走査式共焦点型光学顕微鏡
JPH04505061A (ja) * 1990-01-11 1992-09-03 アイ　リサーチ　インスティテュート　オブ　レティナ　ファウンデイション 走査可能なマイクロレーザ光源を使った像を作成する装置と方法
JPH04265918A (ja) * 1990-11-10 1992-09-22 Carl Zeiss:Fa 被検査体を３次元検査するための同焦点光路を有する光学式装置
JPH07181023A (ja) * 1993-09-30 1995-07-18 Komatsu Ltd 共焦点光学装置
JPH08152308A (ja) * 1994-09-30 1996-06-11 Komatsu Ltd 共焦点光学装置
JPH08233544A (ja) * 1995-02-28 1996-09-13 Komatsu Ltd 共焦点光学装置

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Publication number Priority date Publication date Assignee Title
JPS5791445A (en) * 1980-10-08 1982-06-07 Zeiss Stiftung Luster microscopic spectrochemical analysis method of and apparatus for spatial distribution of sample parameter
JPH01503493A (ja) * 1987-03-27 1989-11-22 ザ ボード オブ トラスティーズ オブ ザ リーランド スタンフォード ジュニア ユニバーシティ 走査式共焦点型光学顕微鏡
JPS63274142A (ja) * 1987-05-06 1988-11-11 Canon Inc 位置合せ装置
JPS63286752A (ja) * 1987-05-20 1988-11-24 Toshiba Mach Co Ltd パタ−ンの欠陥検査または寸法測定方法
US4806004A (en) * 1987-07-10 1989-02-21 California Institute Of Technology Scanning microscopy
US4845552A (en) * 1987-08-20 1989-07-04 Bruno Jaggi Quantitative light microscope using a solid state detector in the primary image plane
JPH04505061A (ja) * 1990-01-11 1992-09-03 アイ　リサーチ　インスティテュート　オブ　レティナ　ファウンデイション 走査可能なマイクロレーザ光源を使った像を作成する装置と方法
JPH04265918A (ja) * 1990-11-10 1992-09-22 Carl Zeiss:Fa 被検査体を３次元検査するための同焦点光路を有する光学式装置
JPH07181023A (ja) * 1993-09-30 1995-07-18 Komatsu Ltd 共焦点光学装置
JPH08152308A (ja) * 1994-09-30 1996-06-11 Komatsu Ltd 共焦点光学装置
JPH08233544A (ja) * 1995-02-28 1996-09-13 Komatsu Ltd 共焦点光学装置

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11054365B2 (en) 2016-02-23 2021-07-06 Shimadzu Corporation Microscopic analysis device
CN110596720A (zh) * 2019-08-19 2019-12-20 深圳奥锐达科技有限公司 距离测量系统

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