JPH0921627A - Shape-measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily register an object to be measured and an automatic collimator main body, by arranging, between the object to be measured and a display plate, an object lens having a focal length of the same as the distance from the display plate. SOLUTION: A light of a light bulb 1 passing through a reticle 4 penetrates an object lens 5 to an object 15 to be measured. The lens 5 is fixed to a main body 8 so that the distance between the reticle 4 and the lens 5 becomes equal to focal length of the lens 5. Unless a first surface 15a and a second surface 15b of the object 15 to be measured are completely parallel to each other, respective reflecting lights form images at different positions of the reticle 4. While the reflecting light from the first surface 15a forms images at the same position of the reticle 4 at all times, the reflecting light from the second surface 15b forms images at different positions on the reticle 4 depending on angle to the first surface 15a if the second surface 15b is not parallel to the first surface 15a. A parallelism of the object 14 to be measured is obtained by reading difference of two images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an autocollimator used for measuring the parallelism of transparent substrates.

[0002]

2. Description of the Related Art The autocollimator described in this specification is a Japanese Industrial Standard "autocollimator" (JIS
B 7538). This standard specifies the autocollimator and the reflecting mirrors attached to it. As a note about the autocollimator, "A line of sight is placed on the focal plane of the objective lens of the telescope, and the light that passes through the objective lens is illuminated by the reflector and placed again in front of the telescope. In addition, when the position of the image of the marked line formed on the focal plane by the objective lens is a telescope of a structure that can be measured by a scale placed there, and the positional relationship between the reflecting mirror and the telescope changes as an inclination, It is used for small angle measurement, surface measurement, or surface setting by utilizing the movement of the image position. "

FIG. 4 is a sectional view showing the structure of a general autocollimator. The structure includes a light source 21, a power source 33 for the light source, a condenser lens 22, a marking plate 24, a semitransparent mirror prism 23, an objective lens 26, a scale plate 25, an eyepiece lens 27, and casings 28, 29 and 30. The configuration of these is as follows. The light emitted from the light source 1 is condensed on the marking plate 24 by the condenser lens 22.
The condensed light passes through the semi-transparent mirror prism 23 and is collimated by the objective lens 26 to be irradiated. And
The light reflected by the object to be measured is condensed by the objective lens 26 and applied to the semi-transparent mirror prism 23. Further, since the position of the scale plate 25 of the objective lens 26 is the focus position, the light transmitted through the semi-transparent mirror prism 23 is focused on the scale plate 25. At this time, an image of the marked line drawn on the marked plate 24 is formed on the scale plate 25.

FIG. 6 is an external view of the structure of this automatic collimator. In the conventional aurocollimeter, the object to be measured 15 is held by a holder 36 as shown in FIG. The autocollimator body 28 is held by a stand 34. The holder 36 and the stand 34 are fixed to the surface plate 35. The stand 34 has an up-down mechanism, a left-right slide mechanism, a tilt, and a rotation mechanism, which are used to adjust the optical axis. The position of the autocollimator main body 28 is adjusted so that the image of the marked line enters the visual field.

Next, a case will be described in which the parallelism between two opposing surfaces of a transparent optical component is measured using this autocollimator. First, before the measurement, it is necessary to position the optical axis 31 of the autocollimator with respect to the measured object 15. First, the positions of the holder 36 and the stand 34 are aligned by visual inspection. Next, the power source 33 for the light source is driven to turn on the light source. Then, the operator looks into the eyepiece of the autocollimator body 28 and adjusts the position of the autocollimator body 28 so that the image of the marked line enters the visual field. As you make adjustments, the images of the marked lines will be visible in two places within the field of view. The image of one of the marked lines is a reflection image from the surface of the DUT 15,
The image of the other marked line is a reflection image from the back surface of the DUT 15. The position of the auto-collimator main body 28 is adjusted so that the images of these marked lines are both on the scale line in the visual field. Finally, position adjustment is performed until the image of one of the marked lines comes to a predetermined position in the field of view (for example, the position of the scale 0). This means that you have finished positioning.

Next, the work for measuring the parallelism of the substrate is started.
The measurement measures how far away the image of the dark marked line is from a predetermined position in the visual field. In practice, the measurer only has to read the scale that is referenced to the predetermined position. FIG. 5 is an optical path diagram showing the state at that time. Light source 21
Is incident on the DUT 15 via the condenser lens 22, the marking plate 24, the semitransparent mirror prism 23, and the objective lens 26. Since the back surface 15b of the DUT 15 is a surface perpendicular to the optical axis, the light reflected by this surface returns through the same optical path and passes through the objective lens 26 and the semitransparent mirror prism 23 to reach the focal position of the objective lens 26. An image of the marked line is formed at the position of Ma on the scale plate 25 placed. On the other hand, the light reflected by the front surface 15a of the measured object having the inclination θ with respect to the rear surface 15b of the measured object is incident on the objective lens 26 with an inclination of 2θ with respect to the optical axis 31 of the incident light, and the semi-transparent mirror. Scale plate 25 through prism 23
In order to reach, the image of the marked line is formed at the position of Mb on the scale plate 25.

Here, if the distance between the positions Ma and Mb of the two reference line images is d, the relationship between the inclination θ and the following equation is obtained. However, f is the focal length of the objective lens.

[0008]

[Equation 1] Therefore, the inclination θ can be known by measuring d. The inclination θ is the parallelism of the front surface 15a of the measured object when the back surface 15b of the measured object is used as the reference surface. In this description, 15b is used as the reference surface, but the same is true when measurement is performed using 15a as the reference surface. At that time, the image of the dark gauge line is adjusted so as to be at the position of the scale 0, and the scale where the image of the thin mark line is located is read.

By the way, in the object to be measured 15 in the optical path diagram of FIG. 5, the optical path incident on 15b and the optical path reflected by 15b are depicted as the same, but in reality, they are different optical paths. However, since the difference in the optical path is very small, the same line is used for convenience in FIG. The present invention does not differ in the interpretation of the invention due to this difference.

[0010]

The above-mentioned conventional technique has a problem that it takes time to position the object to be measured and the autocollimator. Moreover, since a mechanism for performing positioning is required, many parts are required as an autocollimator, which is inconvenient to carry.

Furthermore, the conventional autocollimator requires a power cable for the light source, which hinders positioning work and measurement work. Further, even if the positioning is completed, there is a problem that the autocollimator main body moves due to the tension of the power cable unless the adjustment mechanism of the stand is locked. Therefore, it is an object of the present invention to provide an autocollimator in which the object to be measured and the autocollimator main body can be easily positioned.

[0012]

To achieve the above object, in a shape measuring apparatus according to the present invention, in claim 1, light from a light source is applied to an object to be measured, and the light from the first surface of the object is measured. In a shape measuring device that measures the shape of an object to be measured from the deviation between the optical axis of the reflected light and the optical axis of the light reflected from the second surface, the reflection from the light source to reach the object to be measured. A member and a display plate in which a marked line pattern is drawn on a portion through which the reflected light of the reflecting member passes, and a measuring scale is drawn on a portion through which the reflected light from the first surface of the DUT passes. And an objective lens arranged between the object to be measured and the display plate and having a focal length the same as the distance from the display plate (the invention according to claim 1).

Further, the display plate and the reflecting member of the invention of claim 1 are more preferable when the reflecting member is attached to the position where the marked line pattern of the display plate is drawn than the case where the reflecting member is individually provided on the cover. 2 invention). Further, it is preferable that the display plate is provided with a light-shielding film in the portion where the marked line pattern is drawn, because the shadow of the reflecting member can be hidden (the invention according to claim 3).

By the way, it is further preferable to further include a workpiece contact member having a shape parallel to the first surface of the workpiece on the periphery of the objective lens (the invention according to claim 4). Further, it is preferable that the member for contacting with the object to be measured is integrally formed with a lens barrel for fixing the display plate (the invention according to claim 5). Further, the shape measuring device according to claim 1, further comprising a light source,
It is preferable to include a battery housing portion for housing a battery used as electric power to be supplied to the light source, and an electric wire for electrically connecting the battery housing portion and the light source (the invention according to claim 6).
In addition, it is preferable to include a condenser lens that is disposed between the light source and the reflecting member, has a focal length that is the same distance as the distance from the display plate, and condenses the light from the light source onto the display plate. Invention).

The embodiments of the present invention will be described below, but the present invention is not limited thereto.

[0016]

1 is a sectional view of an autocollimator which is a shape measuring apparatus according to an embodiment of the present invention. The autocollimator of FIG. 1 has a light bulb 1 as a light source, and the light bulb 1 is held and fixed by a light bulb fixing member 10. The light bulb fixing member 10 is fixed to the main body 8.

A condenser lens 2, a focusing screen 4, and an objective lens 5 are fixed to the main body 8. Also, the main body 8
Has an opening on the objective lens 5 side, and the peripheral edge of the opening can be brought into contact with the DUT 15. The peripheral portion is thicker than other portions of the main body 8 and is easy to hit the object to be measured 15. Further, the surface formed by this peripheral portion is the objective lens 5
Is formed so as to be perpendicular to the optical axis of. By doing so, the optical axis of the objective lens 5 can be made perpendicular to the first surface 15a of the object to be measured.

By the way, the condenser lens 2 is arranged between the focusing screen 4 and the electric bulb 1. Further, the condenser lens 2 and the focusing screen 4 are fixed at such positions that the path length of the light condensed by the condenser lens 2 is the same as the focal length of the condenser lens 2. . The prism 3 is fixed to the focusing screen 4. This prism 3 is for reflecting the light from the light bulb 1 so as to be parallel to the optical axis of the objective lens 5. By directly fixing the prism 3 to the focusing screen 4 in this manner, the prism 3 can be attached more easily than fixing the prism to the main body 2.

The light transmitted through the condenser lens 2 passes through a green filter (not shown), is reflected by the prism 3, and enters the focusing screen 4. By the way, the focusing screen 4 used is that shown in FIG. The focusing screen 4 is a circular glass plate. Chromium vapor deposition was applied to a part of the surface Fb of the focusing screen 4 except for a part thereof. The portion not subjected to chromium vapor deposition had the same shape as the marked line. Therefore, the dark field is such that only the shape of the marked line is outlined. Then, since the portion having the same shape as the marked line coincides with the focal position of the condenser lens 2, the light of the light bulb 1 is brightly illuminated on the portion having the same shape as the marked line. By doing so, it is possible to irradiate the objective lens 5 with light in a state where the shadow of the chromium vapor deposition trace is clear.

On the other hand, on the other part Fa of the surface of the focusing screen 4,
The scale is drawn by chromium vapor deposition. The positions of the marked lines and the positions of the scales are substantially equal to the center of the focusing screen 4. The focusing plate 4 is fixed to the main body 8 so that the optical axis 12 of the objective lens 5 and the center of the focusing plate 4 are aligned. Further, the prism 3 is joined to the position Fb of the focusing plate 4 by a balsam. ing.

The light of the electric bulb 1 that has passed through the focusing screen 4 passes through the objective lens 5 and is applied to the object to be measured 15. The objective lens 5 is fixed to the main body 8 at a position where the distance from the focusing plate 4 to the objective lens 5 and the focal length of the objective lens 5 are the same. Part of the light of the electric bulb 1 that has passed through the objective lens 5 is reflected by the first surface 15a of the object to be measured and is incident on the objective lens 5 again. The light of the electric bulb 1 that has passed through the remaining objective lens 5 is reflected by the second surface 15b of the object to be measured and is incident on the objective lens 5 again. Then, the reflected light of the DUT 15 that has entered the objective lens 5 again forms an image at Fa of the focusing screen 4.

At this time, if the first surface 15a of the object to be measured and the second surface 15b of the object to be measured are not completely parallel, the optical path of the reflected light from the first surface 15a and the second surface 15b. The optical path is different from the optical path of the reflected light. As a result, the positions on the focusing screen 4 formed by the respective reflected lights are different. Further, the reflected light from the first surface 15a is always a surface perpendicular to the optical axis 12 of the objective lens 5, so that the image is always formed at the same position on the focusing screen 4, but the second surface 15b is reflected. If the reflected light is not parallel to the first surface 15a, the first surface 15a
The image forming position on the focusing screen 4 differs depending on the size of the angle with respect to a.

The difference between these two images is read on the scale of Fa on the focusing screen 4 and is calculated by the equation (1),
The parallelism of the DUT 15 can be obtained. In this embodiment, an eyepiece lens 7 is provided on the optical axis of the objective lens 5 as shown in FIG. This eyepiece 7
Are fixed by an eyepiece fixing member 9. The eyepiece fixing member 9 is fixed to the main body 8.
The eyepiece 7 allows the measurer to magnify and see the image. An example of the image is shown in FIG. In FIG. 3, the thickly drawn marked line is the first surface 15a of the object to be measured.
Is the image of the reference line due to the light reflected by, and the thinly drawn reference line is the image of the reference line due to the light reflected by the second surface 15b of the measured object.

By the way, in this embodiment, since the green filter is provided between the condenser lens 2 and the prism 3, the image of the marked line looks green, and the image of the marked line is recognized by the measurer. It's easier to do. Further, in this embodiment, the main body 8 is provided with the battery case 13. A battery 14 serving as a power source of the light bulb 1 can be housed here. Further, the battery case 13 is provided with a switch 12, and when the switch 12 is turned on, electricity is supplied to the electric bulb 1 through the power cable 11 to turn on the light.

[0025]

Embodiments of the present invention will be described more specifically. In one embodiment of the present invention, a halogen lamp rated at 6 volts and 8 watts was used as the light bulb 1, and four AA batteries were used as the battery 14 used as the power source. The wiring inside the battery case 13 is arranged so that the four batteries are arranged in series. The battery case 13 is fixed to the main body 8 of the autocollimator by a fastening member (not shown). It is securely fixed.

The main body 8, the eyepiece lens fixing member 9 and the electric bulb fixing member 10 are made of aluminum alloy, and are lightweight. In addition, the inside of these has a black alumite-treated surface with a black matte coating. The objective lens 5 having a focal length of 275 mm was adopted. And
By drawing the marking lines and scales on one focusing screen 4 and adopting an optical system corresponding thereto, the total length of the autocollimator of this embodiment was 325 mm, and it was possible to make it compact.

Further, the peripheral edge of the opening of the main body 8 that comes into contact with the object to be measured is machined so as to be perpendicular to the optical axis 16 of the objective lens. As described above, the autocollimator shown in the embodiments and examples of the present invention can be made compact by reducing the number of optical components. Since the number of optical components is small, there is little loss until the light of the bulb 1 passes through the eyepiece lens 7 and enters the eye of the measurer. Therefore, even if the output of the light source is small, the marked line can be displayed with sufficient brightness for the measurer.

Since the output of the light source may be small,
The power supplied to the light source may be small. for that reason,
By incorporating a small battery into the autocollimator,
It became sufficient as the power to supply it to the light source, and the code from the external power supply, which was necessary until now, is no longer necessary. As a result, a portable autocollimator was obtained.

The autocollimator according to the present invention is
The present invention is not limited to the embodiments and examples of the invention.
A green filter (not shown) is inserted between the condenser lens 2 and the prism 3 to make the marked line image easy to see.
Any other color may be used as long as it is colored. However, the optical system needs to be designed according to the wavelength.

Although the prism 3 is joined to the focusing screen 4 by a balsam to be integrated, a synthetic resin adhesive may be used. Alternatively, they may be separately arranged without being joined. And
The marked line drawn on Fb of the focusing screen 3 is formed by chromium vapor deposition to make the prism shape inconspicuous,
Chromium vapor deposition may not be applied. At that time, the shape of the prism is conspicuous, but the effect of the present invention is not adversely affected. The film formed on Fb of the focusing screen 3 need not be a chromium film. In short, any structure may be used as long as it does not allow light to pass through other than the shape of the marked line.

The periphery of the opening on the objective lens side of the main body 8 of the autocollimator is machined so as to be perpendicular to the optical axis 12 of the objective lens. A mechanism may be provided in which the peripheral portion of the section is divided and the peripheral portion is adjusted to be perpendicular to the optical axis 12. In order to further reduce the weight of the autocollimator, the main body 8, the eyepiece lens supporting member 9, and the light bulb fixing member 10 may be made of plastic.

Optical parts to be measured by this autocollimator include an optical flat, a half mirror, a prism and a filter.

[0033]

As described above, the shape measuring apparatus according to the present invention can reduce the number of optical components and can be made extremely compact. In addition, the measurer can complete the positioning simply by touching the periphery of the opening on the objective lens side of the autocollimator and the surface of the DUT.

Further, the power supply provided in the shape measuring apparatus does not obstruct the work because the power cable is unnecessary. In addition, because it is made small and lightweight, it can be measured by hand. Therefore, the work posture is not limited, and the measurement can be easily performed. Therefore, there is an advantage that even a large measurement object or a measurement object incorporated therein which cannot be fixed to the stage can be measured. .

[Brief description of drawings]

FIG. 1 is a sectional view of an autocollimator that is an example of an embodiment of the present invention.

FIG. 2 is a diagram showing a focusing screen 4.

FIG. 3 is an enlarged view of a focusing screen seen from an eyepiece lens of an autocollimator which is an example of an embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of a conventional autocollimator.

FIG. 5 is a side view showing an arrangement of an optical system of a conventional autocollimator.

FIG. 6 is a side view showing an arrangement of an object to be measured and an autocollimator at the time of measurement by a conventional autocollimator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light bulb 2 ... Condenser lens 3 ... Prism 4 ... Focus plate Fa ... the part where the scale of the focus plate 4 is drawn Fb ... ... Objective lens 7 ... Eyepiece 8 ... Main body 8a ... Cable 12-Power switch 13-Battery holder 14-Battery 15-DUT 16-Optical axis of objective lens 21 ... Light bulb 22 ... Condenser lens 23 ... Semi-transparent prism 24 ... -Marking plate 25 ... Scale plate 26 ... Objective lens 27 ... Eyepiece lens 28, 29, 30 ... Housing 31 ... Optical axis of objective lens 32 ... Power cable 33 ...・ Power source for light source 34 ・ ・ ・ Stand 35 ... platen 36 ... holder

Claims (7)

[Claims] 1. An object to be measured is irradiated with light from a light source, and the object to be measured is shifted from the optical axis of reflected light from the first surface of the object to be measured and the optical axis of reflected light from the second surface of the object to be measured. In a shape measuring device for measuring the shape of a measurement object, a reflecting member that reflects light from the light source so as to reach the object to be measured, and a marked line pattern is drawn on a portion where reflected light of the reflecting member passes, And a display plate on which a measuring scale is drawn in a portion through which the reflected light from the first surface of the measured object passes, and is arranged between the measured object and the display plate,
A shape measuring apparatus comprising an objective lens having a focal length that is the same as the distance from the display plate. 2. The shape measuring device according to claim 1, wherein the reflection member is attached to a position where a marked line pattern of the display plate is drawn. 3. The shape measuring apparatus according to claim 1, wherein the display plate is provided with a light shielding film in a portion where the marked line pattern is drawn. 4. The object contacting member having a shape parallel to the first surface of the object to be measured is provided on the peripheral edge of the objective lens, according to any one of claims 1 to 3. The shape measuring device according to one item. 5. The shape measuring apparatus according to claim 4, wherein the workpiece engaging member is integrally formed with a lens barrel for fixing the display plate. 6. A light source, a battery housing portion for housing a battery used as electric power to be supplied to the light source, and an electric wire for electrically connecting between the battery housing portion and the light source. 5. The shape measuring device according to any one of 1 to 5. 7. A condenser lens disposed between the light source and the reflection member, having a focal length that is the same distance as the distance from the display plate, and condensing light from the light source onto the display plate. The shape measuring device according to claim 1 or 6, further comprising: