JP2788168B2 - Length measuring instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact-type measuring instrument widely used in the measuring field of the general manufacturing industry, and particularly to an object to be measured which is easily deformed or damaged. For measuring length.

[0002]

2. Description of the Related Art Conventionally, a length measuring device for measuring the shape, thickness, parallelism and the like of an object is roughly classified into a contact type and a non-contact type length measuring device, and a high resolution is required. For this measurement, a contact type length measuring instrument is used.

The structure of the main part of this contact type length measuring device is shown in FIG.
As shown in (a) and (b), the probe 51 is attached so as to perform a seesaw motion about the rotary bearing 52.
The tip of the probe 51 is formed in a spherical shape. And
The tip of the probe 51 is pressed against the object to be measured, and the swing width of the probe 51 when the object or the length measuring device 50 is moved is detected.

The length measuring device 50 has a pressure spring 53 and a shock absorbing damper at the rear end of the probe 51 in order to prevent breakage and keep the tip of the probe 51 from separating from the object to be measured. 54 are arranged to face each other.

There are two types of length measuring devices 50 depending on the detection method. The length measuring device 50 shown in FIG. , Probe 5
A bar-shaped iron piece 55 attached to the rear end of the coil 1 is detected as a change in the impedance of the coil 56 that occurs when the bar-shaped iron piece 55 moves in and out of a coil 56 provided separately.

[0006] The length measuring device 50 shown in FIG. 7 (b) is of a photoelectric type, and the number of times the rod 59 attached to the rear end of the probe 51 blocks the photoelectric slit 60 is determined by the laser diode 57. By performing detection using the phototransistor 58 and the like, each is converted into a change in height and detected.

[0007]

However, the contact type length measuring device 50 has a problem that a contact pressure with an object to be measured is large, and a soft thickness before firing is formed on a multilayer chip capacitor, an IC package or the like. An object to be measured, such as a film pattern, which is easily deformed and easily damaged, cannot be measured.

That is, the probe 51 of the contact type length measuring device 50
When the tip of is brought into contact with the object to be measured,
The resultant force of the weight of the probe 51, the sliding resistance in the bearing 52, and the elastic force of the pressure spring 53 acts as a contact pressure, and the object to be measured is formed on the laminated chip capacitor, the IC package, or the like. In the case of the previous soft thick film pattern or the like, the contact pressure is too large, and when either the contact type length measuring device 50 or the object to be measured is moved, the probe 51 shaves the surface of the thick film without swinging and cannot be measured. There was such a problem.

In the measurement of an object to be measured which is slightly harder than the thick film, even if the deflection of the probe 51 can be detected, the sliding resistance in the bearing 52 and the pressure spring 53 are determined by the deflection width of the probe 51. It is difficult to measure with a constant contact pressure at all times because the elastic force of the spring changes, and the pressure spring 53 easily vibrates due to external mechanical vibration. Was low.

To reduce the contact pressure with the object to be measured, various measures such as material change and design change have been made. However, a probe 51, a bearing 52, a pressure spring 53,
With the current contact type length measuring device 50 constituted by components such as the shock absorbing damper 54 and the weight and resistance of the device, it is difficult to reduce the contact pressure, and the measuring device measures the object to be deformed or damaged easily. I couldn't.

Further, such a pressure spring 53 and a shock absorbing damper 54 are vulnerable to an impact load, are subject to aging over a short period of time, and in particular, the reproducibility of measurement is deteriorated due to the backlash of compression and elongation. There was also.

An object of the present invention is to realize high-precision measurement of a soft and easily deformed object or an easily damaged object as described above without causing deformation or damage. To provide a contact-type length measuring device.

[0013]

In view of the above-mentioned problems, the present invention has been made in consideration of the above-mentioned problems, and is a non-contact type length measuring device which detects a surface shape of an object to be measured by converting the surface shape into a change in back pressure obtained by gas injection. The injection member has a detection member attached to the injection nozzle to constitute a length measuring device. The detection member is configured such that a piston is loosely fitted into an inner hole of a cylinder, and an input chamber is provided at a front end and an output chamber is provided at a rear end. Gas supply holes for supplying gas to the piston and supporting the piston under static pressure, and a gas injection hole at the tip of the cylinder, each communicating with the inner hole of the cylinder. At the same time, a pressure receiving plate provided with a probe is provided with a gap in front of the gas injection hole.

[0014]

According to the length measuring device of the present invention, when the probe is brought into contact with the surface of the object to be measured and either the length measuring device or the object to be measured is moved, the probe follows the shape of the object to be measured. After the pressure plate moves up and down, the amount of movement of the probe and the pressure plate is detected as a change in gas pressure, and the change in gas pressure is transmitted to a non-contact length measuring device via a piston for measurement. I do.

That is, the length measuring device of the present invention can measure the amount of movement of the probe and the pressure receiving plate by converting the amount of movement into the amount of change in gas pressure.

The movable portion of the detecting member includes a probe, a pressure receiving plate,
Since it is composed of a film, the weight of the movable part can be minimized, and the gas pressure supplied from the gas injection holes is ejected from the gas injection holes to the pressure receiving plate. By adjusting the gas pressure to be applied, the ejection pressure from the gas ejection holes can be adjusted. Therefore, the measurement can be performed with an optimum contact pressure according to the object to be measured, and the measurement can be performed with a very small contact pressure of 1 g or less.

Further, since the piston of the detecting member is supported by the static pressure by the gas pressure from the gas injection hole, the sliding resistance of the piston is extremely small. As a result, the amount of change in the back pressure from the pressure receiving plate can be transmitted to the non-contact type length measuring device with almost no variation, so that excellent measurement accuracy can be realized.

[0018]

Embodiments of the present invention will be described below.

FIG. 1 is a partially cutaway perspective view of a length measuring device 30 according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a detecting member 1 which is a main part of FIG.

As shown in FIG. 1, the length measuring device 30 according to the embodiment of the present invention employs a method (not shown) such as bolting or screwing to the tip of an injection nozzle 35 of a gas injection type non-contact length measuring device 31. Thus, the detection member 1 is attached.

The non-contact type length measuring device 31 includes a piston 33
One of the two pressurizing chambers formed in the cylinder 34 is set as a reference pressurizing chamber 38, and a reference gas pressure is supplied to the pressurizing chamber 38 from a gas supply hole 39. The other pressurizing chamber 37 is provided with an injection nozzle 35 (hereinafter, referred to as an injection nozzle 35) mounted on the tip end side of the rod 32 projecting from the piston 33.
The nozzle 35 is connected to the inner hole 35 a through a tube 40. The nozzle 35 is provided with an outer hole 35b on the outer periphery of the inner hole 35a, and a gas supply hole 35c is provided in communication with the outer hole 35b.
The gas pressure supplied from 5c is ejected from the outer hole 35b, and the back pressure is taken into the pressurizing chamber 37 from the inner hole 35a. Further, at the rear end of the rod 32, a piston 3
A micrometer 36 for measuring the amount of displacement of 3 is attached to the cylinder 34.

The principle of operation of the non-contact type length measuring device 31 is that a reference pressure is supplied to the pressurizing chamber 38 from the gas supply hole 39,
If the gas pressure is also supplied to the gas supply hole 35c of the nozzle 35 and is ejected from the tip of the nozzle 35 to the object to be measured, the back pressure from the object to be measured passes through the inner hole 35a of the nozzle 35 and the pressure chamber 37
The piston stops at a position where the pressures of the upper and lower pressurizing chambers 37 and 38 are balanced, and the nozzle 35 stops at a certain distance from the object to be measured. Here, if the object to be measured is moved, the back pressure taken in from the nozzle 35 changes according to the surface shape, and the piston 33 automatically follows the pressure change. It moves up and down while keeping a constant distance along the shape, and the amount of movement of the nozzle 35 is detected by the micrometer 36 so that the surface shape of the object to be measured can be measured.

On the other hand, the nozzle 3 of the non-contact type length measuring device 31
As shown in FIG. 2, the detection member 1 disposed at 5 includes a spring 10 on the bottom surface of the inner hole of the cylinder 2, and a piston 3 supported by the spring 10, and is isolated by the piston 3. The lower room is referred to as an input room 14 and the upper room is referred to as an output room 15. A gas supply hole 4 and a release hole 13 for supporting the piston 3 under static pressure are formed in the side wall surface of the cylinder 2 so as to communicate with the inner hole of the cylinder 2. At the center of the surface, there is provided a gas injection hole 5 as shown in FIG. Further, at the tip of the cylinder 2, four plate-like members 9 are provided at intervals of 90 ° along the circumferential direction.
A cross-shaped film 8 as shown in FIG. 1 is attached with a gap 12 provided between the gas injection hole 5 and a ceramic pressure receiving plate 7 having a probe 6 made of diamond, sapphire, or the like at the center of the film 8. The film 8, the pressure receiving plate 7, and the probe 6 form a movable portion.

The principle of operation of the detection member 1 is that, when the probe 6 is moved while being in contact with the surface of the object 40, the probe 6 moves up and down in accordance with the surface shape of the object 40. After the amount of movement is converted into the amount of change in the back pressure generated by the pressure receiving plate, it is transmitted to the nozzle 35 of the non-contact type length measuring device 31 via the piston 3.

On the outer wall surface of the piston 3 provided in the detecting member 1, as shown in FIG. 5, a number of vertical grooves 3d are formed along the axial direction and blast grooves 3 communicating with the vertical grooves 3d.
e, and one horizontal groove 3f is formed so as to be orthogonal to the vertical groove 3d, and the width W is 3 to 10 μm, preferably 3 to 10 μm, between the piston 3 and the cylinder 2 having the throttle groove 3b. A gap 11 of about 4 μm is provided.

The reason why the width W of the gap 11 is set to 3 to 10 μm is that the width W of the gap 11 is smaller than 3 μm.
Is too narrow to form a gas pressure layer in the gap 11 between the piston 3 and the cylinder 2 and the piston 3
Not only can not be supported by the static pressure, but also because the gas pressure cannot be ejected from the gas injection holes 5. Conversely, when the width W of the gap 11 is larger than 10 μm, the gas pressure injected from the gas supply holes 4 increases the piston pressure. This is because the pressure is weakened to reach the throttle groove 3b of No. 3 and the piston 3 cannot be supported by the static pressure.

The throttle groove 3b of the piston 3 may have any shape as long as a uniform gas pressure layer can be formed in the gap 11 between the cylinder 2 and the piston 3.

The detecting member 1 has a gap 12 between the gas injection hole 5 and the pressure receiving plate 7.
2 must be formed with a width V of 10 to 100 μm. In other words, when the width V of the gap 12 is smaller than 10 μm, if there is a convex portion on the surface of the DUT 40, the pressure receiving plate 7 which has been momentarily pushed upward comes into contact with the gas injection holes 5 and the measurement is performed. On the contrary, if the width V of the gap 12 is larger than 100 μm, the back pressure from the pressure receiving plate 7 cannot be detected, and the measurement becomes impossible.

Further, the gas injection holes 5 of the detection member 1
Is formed from three holes so as to keep the pressure receiving plate 7 horizontal, but the number of holes is not limited, and may be provided according to the size of the pressure receiving plate 7.

Further, the movable portion composed of the probe 6, the pressure receiving plate 7 and the film 8 may be arranged in any manner on the plate-like body 9, and the arrangement method and the number of the plate-like body 9 are not limited. It is necessary to arrange so that at least the gap 12 in the above range is provided between the gas injection hole 5 and the gas injection hole 5.

On the other hand, the material of the cylinder 2, the piston 3 and the pressure receiving plate 7 constituting the detecting member 1 may be resin or plastic, but is preferably formed of ceramics. For example, the cylinder 2, the piston 3, and the pressure receiving plate 7 formed of alumina ceramic, silicon carbide ceramic, silicon nitride ceramic, or the like are:
Due to its excellent chemical resistance and heat resistance, the detection member 1 is not deformed or rusted even in a high-temperature or humid environment, or even in a measurement using a corrosive gas. In addition, since the specific gravity is small, the piston 3 has good sensitivity to minute pressure, and the pressure receiving plate 7 is suitable for reducing the contact pressure with the object 40 to be measured. Thus, the excellent detection member 1 can be obtained.

The material forming the detecting member 1 is not limited to the above ceramics only.
Needless to say, it may be made of other ceramics.

It is desirable that the film 8 for arranging the pressure receiving plate 7 at the tip of the gas injection hole 5 be made of a material that is as strong as possible to bending and has a small specific gravity, such as stainless steel or polyethylene.

Next, the operation principle of the length measuring device 30 according to the present invention will be described with reference to FIGS. First, when the non-contact type length measuring device 31 is actuated and gas pressure is ejected from the nozzle 35 to the piston 3 of the detection member 1 and gas pressure is also supplied from the gas supply hole 4 of the detection member 1, While the piston 3 that is loosely fitted into the piston 3 is supported by the static pressure without being supported by the spring 10, the gas pressure flowing into the output chamber 15 is released to the outside air through the release hole 13, and the gas pressure flowing into the input chamber 14 is The pressure is applied to the pressure receiving plate 7 from the injection hole 5. Here, when the probe 6 provided on the pressure receiving plate 7 is brought into contact with the measured object 45, the pressure receiving plate 7 is pushed up,
The back pressure from the pressure receiving plate 7 is taken into the input chamber 14. Then, the piston 3 moves to a position where the force that the back pressure pushes the piston 3 and the force that the gas pressure ejected from the nozzle 35 of the non-contact type length measuring device 31 pushes the piston 3 become equal, and the piston 3 stops. At this time, the back pressure from the piston 3 is also taken into the non-contact length measuring device 31.

Next, the object 45 is moved, and the detecting member 1 is moved.
When the probe 6 comes to the convex portion of the object 45 to be measured, the pressure receiving plate 7 is pushed up by the height of the convex portion, so that the back pressure taken into the input chamber 14 increases, and the force acting on the piston 3 is reduced. The piston 3 goes up until it is balanced. At this time, as the piston 3 rises, the back pressure taken into the non-contact type length measuring device 31 also increases, so that the piston 33 automatically follows and moves.
The contact pressure with the object 45 is controlled to be always constant, and the movement amount of the piston 33 is measured by the micrometer 36. When it comes to the concave portion of 45, the reverse operation is performed and measurement is performed.

The length measuring device 30 of the present invention also has the function of an amplifier in the detecting member 1. The amplification factor is determined by the area ratio between the area of the lower surface of the piston 3 and the effective area of the outer hole 35b of the nozzle 35. Is determined. For example, if the area of the lower surface of the piston 3 is A and the effective area of the outer hole 35b of the nozzle 35 is B, the amplification factor is A / B, and the back pressure from the pressure receiving plate 7 is amplified to A / B. Since it can be taken into the non-contact type length measuring device 31, it is possible to measure even a minute back pressure, and it is possible to provide a highly reliable length measuring device 30.

As described above, the length measuring device 30 of the present invention is capable of measuring the movement amount of the pressure receiving plate moving up and down along the shape of the object 45 to be measured.
The pressure can be converted to a gas pressure, and the gas pressure can be transmitted to the non-contact length measuring device 31 for detection. In addition, if the gas pressure supplied to the gas supply hole 4 of the detection member 1 is adjusted,
Since the contact pressure with zero can be adjusted, measurement is possible even with a very small pressure.

For this reason, if the length measuring device 30 of the embodiment of the present invention is used, it is susceptible to deformation such as a thick film pattern formed on a laminated chip capacitor or an IC package, etc. It is possible to measure even the measurement object 45 that is easily attached.

The length measuring device 30 of the present invention is not limited to the non-contact type length measuring device 31 shown in the embodiment, but can measure the length in a non-contact state by injecting gas pressure. Any device provided with the detection member 1 may be used.

EXPERIMENTAL EXAMPLE Using a length measuring device 30 of the present invention shown in FIG. 1, the measurement accuracy when a 1 mm thick block gauge was repeatedly measured 20 times was confirmed.

The detecting member 1 of the length measuring device 30 of the present invention comprises a probe 6 made of diamond having a diameter of 1 mm and a length of 1 mm, a pressure receiving plate 7 made of an alumina ceramic having a diameter of 3.5 mm and a thickness of 0.06 mm, and a film. 8 made of stainless steel having a thickness of 0.02 mm, and the weight of the movable part was reduced to 0.03 mm.
g. The detection member 1 has a diameter of 1.0 mm.
The piston 3 has a diameter of 10 mm, and the piston 3 and the cylinder 2 are formed of alumina ceramics.

The diameter of the outer hole 35b of the nozzle 35 of the non-contact length measuring device 31 is 2.2 mm, and the amplification factor is set to about 20 times.

The nozzle 35 of the non-contact length measuring device 31
By supplying a gas pressure of 0.2 g to the gas supply hole 4 of the detection member 1 while supplying a gas pressure of 2 g from
When the measurement was performed with the ejection pressure from the gas ejection hole 5 set to 0.08 g, the contact pressure applied to the block gauge was the sum of the weight of the movable part and the ejection pressure, and the contact pressure with the object to be measured was 0.1%. 11 g. As a result of measuring the thickness of the block gauge under such measurement conditions, the average value of the measured data was 1.00024 mm, and the variation (reproducibility) of the going and returning data when reciprocated was It was found that extremely high accuracy of 0.09 μm can be measured.

Next, using the length measuring device 30 of the present invention,
A thick film pattern having a height of 5 μm and a width of 80 μm made of a molybdenum alloy formed on a ceramic substrate was measured.

The conditions were the same as in the above experiment.

FIG. 6 shows the result. However, the thick film is located between 5 and 85 μm at the measurement position.

As can be seen from FIG. 6, the plotted points substantially trace the thick film pattern, and the reproducibility of the measurement is very excellent.

[0048]

As described above, according to the present invention, a gas supply hole and a gas injection hole are formed in the side wall and the tip of the cylinder in which the piston is loosely fitted so as to communicate with the inner hole of the cylinder, respectively. At the tip of the gas injection hole, a pressure receiving plate with a probe is provided with a gap to form a detection member attached to a cylinder, and the detection member is attached to an injection nozzle of a gas injection type non-contact length measuring device. With this structure, a non-contact type or contact type length measuring device can be obtained by attaching and detaching the detecting member, which is very practical.

Further, the above-mentioned detecting member can perform measurement with an optimum contact pressure according to an object to be measured only by adjusting the ejection pressure from the gas ejection hole. In addition, the piston that transmits the back pressure to the non-contact length measuring device is supported by static pressure and the weight of the movable part is minimized, so measurement with a very small contact pressure of 1 g or less is possible. It is. For this reason, it is possible to measure even an object to be measured that is easily deformed and easily damaged, such as a thick film pattern formed on a multilayer chip capacitor, an IC package, or the like, which cannot be measured conventionally.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a length measuring device according to the present invention.

FIG. 2 is a longitudinal sectional view showing a detecting member of the length measuring device according to the present invention.

FIG. 3 is a sectional view taken along line XX of a detecting member of the length measuring device according to the present invention.

FIG. 4 is a bottom view of a detecting member of the length measuring device according to the present invention.

FIG. 5 is a perspective view in which a part of a piston provided in a detection member of the length measuring device according to the present invention is partially broken.

FIG. 6 is a graph showing a result of measuring a thick film pattern with the length measuring device of the present invention.

FIG. 7 is a perspective view showing a main part of a conventional contact type length measuring device, wherein FIG. 7 (a) shows an electromagnetic induction type detection method,
(B) is a photoelectric type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection member 2 Cylinder 3 Piston 4 Gas supply hole 5 Gas injection hole 6 Probe 7 Pressure receiving plate 8 Film 9 Plate 10 Spring 13 Release hole 14 Input chamber 15 Output chamber 31 Non-contact length measuring device

Claims (1)

(57) [Claims] A piston is loosely fitted into an inner hole of a cylinder to form an input chamber at a front end side and an output chamber at a rear end side, and a gas supply hole communicating with the inner hole is provided at a side wall and a front end of the cylinder. Each gas injection hole is drilled, and at the tip of the gas injection hole,
Forming a detecting member in which a pressure receiving plate provided with a probe is provided with a gap, and detecting the surface shape, etc., by an amount of change in back pressure obtained by injecting a gas to an object to be measured into an output chamber of the detecting member. A length measuring device with an injection nozzle of a non-contact length measuring device that performs the measurement.