JP5031724B2 - Optical shape / position measuring method and gap forming jig - Google Patents

Description

  The present invention provides an optical device capable of measuring a contour shape and a position of a target object in a non-contact manner based on an amount of measurement light transmitted through the gap or a transmitted light image by forming a gap with a measurement target portion of the target object. The present invention relates to a method for measuring the shape and position of an equation, and a gap forming jig used in this method.

A method for measuring a contour shape and a gap of a target object from an image obtained by a contour projector is known. In Patent Document 1, it is detected that the detection signal of the light receiving unit switches between ON and OFF when the light emitted from the light emitting unit hits the end of the gear teeth while the gear is rotating. A method for measuring the contour shape of a gear tooth in a non-contact manner based on the rotational position of the gear is disclosed. In Patent Document 2, parallel light beams are irradiated to a gap opening between a rolling stand and a roll (cylindrical body), and light passing through the gap opening is monitored with a CCD camera. A method for adjusting a gap by comparing a target value of a light and dark limit corresponding to the above and an actual measurement value by a CCD camera to grasp the size, shape, and position of the gap opening is disclosed.
JP-A-7-71950 JP-A-11-277120

  In the method of detecting the light passing through the gap formed with the target object and grasping the size, shape, or position of the target object, if the gap to be formed is too wide, it will pass with respect to the shape change of the measurement site. The amount of change in light is relatively small, and measurement with high resolution is not possible. When the target object has a contour portion whose shape changes minutely, in order to accurately measure the contour shape of this portion, it is necessary to narrow the gap to be formed and increase the measurement resolution. However, if the gap is narrowed below the wavelength of the measurement light in order to increase the resolution, the measurement light cannot pass through the gap, and the amount of transmitted light becomes insufficient, making measurement impossible. Therefore, in order to measure fine protrusions with a radius of curvature equal to or less than the wavelength of the measurement light with high resolution based on the light that has passed through the gap, an appropriate gap according to the shape change state of the measurement target is formed. There is a need to.

  An object of the present invention is to provide an optical shape / position measurement method for measuring the contour shape and position of a target object based on light passing through a gap formed between the target object and a target object having a minute shape change. An object of the present invention is to make it possible to detect a contour shape, minute unevenness of a target object with high accuracy, and to propose a gap forming jig used for that purpose.

In order to solve the above problems, the optical shape / position measuring method of the present invention is:
A first end face that can be confronted with a first gap with respect to an ideal outline shape of a contour shape portion of a measurement target in a target object, and the first gap with respect to the ideal outline shape. Prepare a gap forming jig having a second end face that can be confronted with a wider second gap,
The first end face of the gap forming jig is opposed to the contour-shaped portion of the measurement target in the target object, and the measurement light is irradiated to the gap formed therebetween,
While confirming the transmitted light amount of the measurement light passing through the gap and / or the transmitted light image, the first end surface is gradually approached to the contoured portion, and the gap forming jig is Positioning so that the first gap is formed with respect to the target object, the first wide locally between the second end face and a specific part of the contoured part that the second end face is opposed to Forming two gaps,
The specific portion of the contour-shaped portion based on the transmitted light amount of the measurement light passing through the gap formed between the second end surface and the specific portion of the contour-shaped portion and / or the transmitted light image And / or the relative position of the target object with respect to the gap forming jig is measured.

  In the method of the present invention, the width of the first gap is set to be narrower than the wavelength of the measurement light, and the width of the second gap is set to be wider than the wavelength of the measurement light. Can do. In this way, when the amount of light transmitted through the first gap is drastically reduced or when the transmitted light image cannot be confirmed, the second end face of the gap forming jig is located on the specific part of the contoured portion to be measured. Thus, it can be known that the positioning state is confronted by the second gap.

  In addition, examples of the contour shape portion of the measurement target in the target object according to the method of the present invention include a contour shape portion in which a protruding portion that locally protrudes at the specific portion is formed. In this case, the second end surface of the gap forming jig may be an end surface having a concave contour that can be opposed to the ideal contour shape of the protruding portion by the second gap.

  In this case, according to the method of the present invention, even if the maximum width or the maximum protrusion amount of the protrusion-like portion to be measured has a size of 1/2 or less of the wavelength of the measurement light, the shape Alternatively, the position can be measured.

  Next, in the method of the present invention, a plurality of the second end faces can be formed at predetermined intervals along the first end face on the first end face of the gap forming jig.

  In this case, it is possible to accurately perform shape measurement when the contour shape portion to be measured has a slight shape change, shape error measurement when the contour shape portion slightly deviates from the ideal contour shape, etc. it can.

  On the other hand, the present invention is a gap forming jig used in the above-described optical shape / position measuring method, and can be opposed to the ideal outline shape of the outline shape portion of the measurement target in the target object with the first gap. A first end face and a second end face formed on a part of the first end face and capable of confronting each other with a second gap wider than the first gap with respect to the ideal contour shape are provided.

  In the method of the present invention, since the second end face such as a fine concave portion is locally formed on the first end face for forming the gap in the gap forming jig, the first end face of the gap forming jig is targeted. When confronting the contour shape portion of the object to be measured with the first gap, the second end surface formed on the first end surface is locally located between the specific portion of the contour shape portion facing the second end surface. Large gaps are formed. If the second gap formed between the second end face and the specific part of the contoured part is set to have a gap size that provides a resolution necessary for the measurement of the specific part, The shape or position can be measured with a desired accuracy. In addition, while observing the gap between the first end face and the contour-shaped portion, the gap-forming jig is positioned close to the contour-shaped portion of the target object, so that the gap-forming jig is accurate with respect to the target object. Therefore, the second gap can be formed with high accuracy.

(Embodiment 1)
FIG. 1 is an explanatory diagram of a gap forming jig and a target object according to Embodiment 1 of the present invention. In the first embodiment, the target object whose contour shape is to be measured is a plate-like tool 2 including the protrusion 1, and the contour shape portion to be measured is the contour shape of the portion of the protrusion 1. Prior to the measurement, a plate-shaped gap forming jig 4 having an end face 3 (first end face) having a contour shape slightly larger than the contour shape of the protrusion 1 is prepared. The end face 3 is set to have a concave shape that is slightly larger outward from the ideal contour shape by a fixed dimension Δ1, based on the ideal contour shape of the protrusion 1, for example, the contour shape as designed.

  FIG. 1 shows a state in which the contour portion of the protrusion 1 and the end surface 3 of the gap forming jig 4 are opposed to each other to form a gap 6 (first gap) having a substantially constant dimension Δ1. Here, the tip end portion 1a (projection-like portion) of the protrusion 1 that faces the innermost portion of the end face 3 is a minute convex portion that protrudes locally locally, and its tip side is an arc surface having a predetermined radius of curvature. It has become. At the innermost part of the end surface 3, a concave contour end surface 5 (second end surface) is formed which is a concentric arc surface separated from the arc surface by a dimension Δ2. In the first embodiment, the dimension Δ2 is set to be larger than the dimension Δ1, and a gap 7 (second gap) wider than the gap 6 can be locally formed between the end face 5, the tip portion 1a, and the vicinity thereof. The shape of the end face 5 is set so that

  In the case of positioning in the state as shown in FIG. 1, the protrusion 1 is made to enter the end surface 3, and the end surface 3 is gradually brought closer to the contoured portion of the protrusion 1. At this time, the width of the gap 6 between the end face 3 and the contoured portion of the protrusion 1 is gradually approached while observing, and the approach is stopped when the width of the gap 6 reaches the dimension Δ1. Thus, the operation of positioning while observing the width of the gap 6 set narrower than the gap 7 can be performed more easily and accurately than the operation of positioning while observing only the gap 7. Therefore, by this method, the gap forming jig 4 can be accurately positioned with respect to the portion of the protrusion 1 of the tool 2, and the gap 7 having a width of the dimension Δ2 can be formed with high accuracy.

  FIG. 2 is an explanatory diagram of a method for detecting a transmitted light image by light passing through the gap forming tool and the tool in FIG. As shown in this figure, a light source 8 for measurement is arranged on one side in the thickness direction of the tool 2 and the gap forming jig 4, and a light receiving device 9 is arranged on the other side. The tool 2 and the gap forming jig 4 are configured to be movable relative to the light source 8 and the light receiving device 9 along the contour shape of the protrusion 1. As a result, the measurement light can be irradiated to any position of the gap 6 or the gap 7, and the light that has passed can be detected by the light receiving device 9.

  As the light source 8, for example, a non-coherent parallel light beam that is made uniform through ground glass, such as a light source of a tool microscope often used for contour measurement, is used. As the light receiving device 9, a CCD camera or the like having a resolution that can detect a transmitted light image of light passing through the gap 6 or the gap 7 is used. When receiving light passing through each position of the gap 6 or the gap 7, a shielding plate (not shown) having an opening of a predetermined shape between the gap 6 or the gap 7 and the light receiving device 9 in order to define a measurement region. You may make it arrange | position. When the contour shape of the transmitted light image is finer than the resolution of the CCD camera, an optical system such as a lens for enlarging the transmitted light image is appropriately installed between the gap 6 or the gap 7 and the light receiving device 9. Thus, it is also conceivable to enlarge the transmitted light image and enter the light receiving device 9.

  FIG. 3 is an explanatory diagram of the detected transmitted light image, and shows the transmitted light image when the vicinity of the tip portion 1a of the protrusion 1 is a measurement region. Here, the tip end portion 1 a of the protrusion 1 in Embodiment 1 has a fine shape such that the maximum width or the maximum protrusion amount is a dimension of ½ or less of the wavelength of the measurement light emitted from the light source 8. In the first embodiment, the shape of the end face 5 is set so that the dimension Δ2 of the gap 7 secured around the fine-shaped tip portion 1a is slightly wider than the wavelength of the measurement light emitted from the light source 8. ing. Further, the end face 3 has a dimension Δ1 of the gap 6 in a state in which the gap forming jig 4 is positioned so that the width of the gap 7 becomes the dimension Δ2 is narrower than the wavelength of the measurement light emitted from the light source 8. The shape is set.

  In the first embodiment, the measurement light can surely pass through the gap 7 by setting the dimension Δ2 of the gap 7 slightly wider than the wavelength of the measurement light. Therefore, the transmitted light image of the light passing through the gap 7 can be reliably detected by the light receiving device 9. In addition, the dimension Δ2 of the gap 7 is set to be a gap dimension that provides a resolution necessary for measuring the contour shape of the tip portion 1a. Therefore, a clear actual contour shape of the tip portion 1a can be determined from the transmitted light image detected by the light receiving device 9. Further, it is possible to determine the relative position of each part of the tool 2 with respect to each part of the gap forming jig 4 by determining the relative position of the tip part 1 a with respect to the end surface 5 from this transmitted light image.

  In this way, by appropriately setting the width dimension Δ2 of the gap 7 in accordance with the contour shape of the measurement target, the relative position with respect to the actual contour shape of the measurement target or the gap forming jig 4 can be set according to the measurement target. Can be measured with the accuracy of. Further, by forming the gap 7 locally only around the distal end portion 1a, positioning for accurately forming the gap 7 is easy. For example, when the dimension Δ1 of the gap 6 is set narrower than the wavelength of the measurement light emitted from the light source 8, the positioning is easily performed by observing whether or not the light passing through the gap 6 can be detected. be able to.

  In addition to the method of directly observing the transmitted light image and directly grasping the actual contour shape of the tip portion 1a, the amount of transmitted light passing through each measurement point along the gap 7 is used as the detection output of each light receiving element of the light receiving device 9. Based on the detected transmitted light quantity, the actual dimension of the width of the gap 7 at each measurement point is calculated, and based on this actual dimension and the position and shape of the end face 5 that are grasped in advance, the tip portion 1a. The actual contour shape may be measured. When detecting the amount of transmitted light, it is preferable to collect the passing light to the light receiving device 9 through a condensing lens focused on the position of the passing gap.

  Further, in order to measure the contour shape of each part of the protrusion 1 excluding the tip part 1a, when the protrusion 1 enters the inside of the end surface 3, the light can pass through the gap 6, for example, the gap 6 The end surface 3 may be positioned with respect to the protrusion 1 in a state where the width is the dimension Δ2. In this state, since the measurement light can pass through the gap 6, the transmitted light image and the transmitted light amount of the light passing through each position of the gap 6 while relatively moving the light source 8 and the light receiving device 9 along the gap 6 are obtained by the CCD. If detected by the light receiving element of the camera, the actual contour shape and position of each part excluding the tip 1a of the protrusion 1 can be measured or observed. Thereafter, if the gaps 6 and 7 are positioned so as to be Δ1 and Δ2, respectively, the actual contour shape of the tip portion 1a can be measured or observed.

(Embodiment 2)
FIG. 4 is an explanatory diagram of a gap forming jig and a target object according to the second embodiment of the present invention. In Embodiment 2, the linear part 10 in said tool 2 is assumed as a measuring object which should measure a contour shape. The gap forming jig 11 includes a linear end surface 12 (first end surface) having a length corresponding to the linear portion 10. The end surface 12 is formed with a minute semicircular concave contour end surface 13 (second end surface) at a constant pitch. Note that the shape of the end face 13 is not limited to a semicircular shape, and may be a polygonal shape such as a rectangular shape or a trapezoidal shape, or another concave shape. In FIG. 4, the straight portion 10 and the end surface 12 are brought close to each other to face each other, and a gap 14 (first gap) having a substantially constant dimension Δ3 is formed between the portion of the end surface 12 excluding the end surface 13 and the straight portion 10. Shows the state. At this time, a gap 15 (second gap) wider than the gap 14 is formed between the innermost portion of the end surface 13 having the concave contour and the straight line portion 10.

  In the second embodiment, as in the first embodiment, the end surface 12 arranged in parallel with the straight portion 10 is gradually approached toward the straight portion 10. At this time, the width of the gap 14 between the end face 12 and the linear portion 10 is gradually approached while observing, and the approach is stopped when the width of the gap 14 reaches a preset dimension Δ3. As a result, the gap forming jig 11 is moved relative to the linear portion 10 of the tool 2 so as to form a gap 15 having a predetermined width Δ4 wider than the gap 14 between the end face 13 and the linear portion 10. Position.

  Then, each position along the gap between the linear portion 10 and the end face 12 facing each other as shown in FIG. 4 is irradiated with measurement light using the light source 8 similar to that of the first embodiment, and the passing light is received using the light receiving device 9. The transmitted light image is detected. FIG. 5 is an explanatory diagram of the detected transmitted light image. Here, the straight line portion 10 in the second embodiment has a minute shape change that has a dimension that is ½ or less of the wavelength of the measurement light emitted from the light source 8. In other words, the straight line portion 10 has a fine shape error of about ½ or less of the wavelength of the measurement light with respect to the straight line shape that is the ideal contour shape. In the second embodiment, when the gap forming jig 11 is positioned with respect to such a straight portion 10, the dimension Δ 4 of the gap 15 is slightly wider than the wavelength of the measurement light emitted from the light source 8, and the gap 14 is set to be narrower than the wavelength of the measurement light emitted from the light source 8.

  With such a setting, the measurement light cannot pass through the gap 14 in the positioning state, and the transmitted light image of the linear portion 10 in the gap 14 cannot be detected by the light receiving device 9. Therefore, positioning can be performed easily and accurately by observing whether or not the light passing through the gap 14 can be detected. Then, since the measurement light can pass through the gap 15, the transmitted light image of the straight portion 10 in the gap 15 is detected by the light receiving device 9.

  Since the end surface 13 having the concave contour is formed at a constant pitch along the linear end surface 12, the entire area of the linear portion 10 is measured while relatively moving the light source 8 and the light receiving device 9 along the linear portion 10. By doing so, it is possible to detect the transmitted light image of the linear portions 10 that are discretely arranged at a constant pitch. Therefore, by drawing a straight line 16 that complements between these discrete transmitted light images, an overall image of the actual contour shape of the straight line portion 10 is obtained. Further, from this transmitted light image, the relative position of each part of the linear part 10 with respect to the end faces 12 and 13 can be determined, so that the relative position of each part of the tool 2 with respect to each part of the gap forming jig 11 is grasped. You can also

  Thus, the measurement light can surely pass through the gap 15 by setting the dimension Δ4 of the gap 15 between the end face 13 and the straight portion 10 to be slightly wider than the wavelength of the measurement light. Therefore, the transmitted light image of the light passing through the gap 15 can be reliably detected by the light receiving device 9. Further, by setting the dimension Δ4 of the gap 15 to be a gap dimension that provides a resolution necessary for measuring the contour shape of the straight line portion 10, the straight line portion can be obtained from the transmitted light image detected by the light receiving device 9. Ten clear actual contour shapes can be discriminated. Alternatively, from this transmitted light image, the relative position of the linear portion 10 with respect to the end surface 13 can be determined, and the relative position of each portion of the tool 2 with respect to each portion of the gap forming jig 11 can be measured.

  In the second embodiment, the amount of transmitted light passing through each gap 15 is detected according to the detection output of each light receiving element of the light receiving device 9, and the relative position between each end face 13 and the linear portion 10 is calculated from the detected amount of transmitted light. Thus, a method of grasping the actual contour shape and position of the straight line portion 10 may be used.

  In the second embodiment, the straight line portion 10 is the contour shape portion to be measured, but the contour shape of a curved portion such as a smooth arc shape can also be grasped by the same method.

It is explanatory drawing of the jig | tool for gap formation which concerns on Embodiment 1, and a target object. It is explanatory drawing which shows the detection method of the transmitted light image by the light which passes through the clearance gap formation jig | tool of FIG. 1, and a tool. It is explanatory drawing of the detected transmitted light image. It is explanatory drawing of the jig | tool for gap formation which concerns on Embodiment 2, and a target object. It is explanatory drawing of the detected transmitted light image.

Explanation of symbols

1 Protrusion 1a Tip part (protruding part)
2 Tool 3 End face (first end face)
4 Gap forming jig 5 End face (second end face)
6 gap (first gap)
7 Gap (second gap)
8 Light source 9 Light receiving device 10 Linear portion 11 Gap forming jig 12 End surface (first end surface)
13 End face (second end face)
14 Gap (first gap)
15 Clearance (second gap)
16 Straight line Δ1-Δ4 Dimensions

Claims (6)

A first end face (3, 12) that can be confronted with a first gap (6, 14) with respect to an ideal contour shape of a contour shape portion (1, 10) to be measured in the target object (2), and the first end face A second end face (5, 13) which is formed in a part of (3, 12) and can be confronted by a second gap (7, 15) wider than the first gap (6, 14) with respect to the ideal contour shape. Prepare a gap forming jig (4, 11) with
The said 1st, 2nd end surface (3, 12, 5, 13) of the said jig | tool for gap formation (4, 11) is set to the said contour shape part (1, 10) of the measuring object in the said target object (2). Let the measurement light illuminate the gap formed between them,
The first end face (3, 12) is gradually approached to the contour-shaped portion while confirming the transmitted light amount of the measurement light passing through the gap and / or the transmitted light image thereof, thereby forming the gap. The jig (4, 11) is positioned with respect to the target object (2) so that the first gap (6, 14) is formed, and the second end face (5, 13) and the second Forming the second wide gap (7, 15) locally wide with the specific part (1a, 10) of the contoured part (1, 10) facing the end faces (5, 13);
Transmitted light quantity of the measurement light that passes through the gap (6, 7) formed between the second end face (5, 13) and the specific part (1a, 10) of the contoured part (1, 10). Based on the transmitted light image, and / or the shape of the specific part (1a, 10) of the contour portion (1, 10) and / or the gap forming jig of the target object (2) An optical shape / position measuring method characterized by measuring a relative position with respect to (4). The optical shape / position measuring method according to claim 1,
Setting the width of the first gap (6) to be narrower than the wavelength of the measurement light;
An optical shape / position measuring method, wherein the width of the second gap (7) is set to be wider than the wavelength of the measuring light. The optical shape / position measuring method according to claim 2,
The contoured part (1) of the measurement target in the target object (2) is formed with a protruding part (1a) that locally protrudes at the specific part,
The second end face (5) of the gap forming jig (4) is an end face having a concave contour that can be opposed to the ideal contour shape of the protruding portion (1a) by the second gap (7). An optical shape / position measuring method. The optical shape / position measuring method according to claim 3,
The optical shape / position measuring method characterized in that the protrusion-like part (1a) to be measured has a maximum width or a maximum protrusion amount that is not more than 1/2 of the wavelength of the measuring light. . The optical shape / position measuring method according to claim 1 or 2,
A plurality of the second end faces (13) are formed at predetermined intervals along the first end face (12) on the first end face (12) of the gap forming jig (11). An optical shape / position measuring method. A gap forming jig (4, 11) used in the optical shape / position measuring method according to any one of claims 1 to 5,
A first end face (3, 12) that can be confronted with a first gap (6, 14) with respect to an ideal contour shape of a contour shape portion (1, 10) to be measured in the target object (2);
A second end face (5, 13) that is formed on a part of the first end face and can be confronted by a second gap (7, 15) wider than the first gap with respect to the ideal contour shape; A gap forming jig (4) characterized by the above.