JP2005055181A - Displacement measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a displacement measuring instrument for simultaneously solving first and second problems, that is, a displacement measuring instrument for performing accurate measurement at all times without being affected by temperature change, cutting a waste of material, and easily forming an encoder pattern. <P>SOLUTION: This displacement measuring instrument 10 is equipped with a main scale 11 and a detection head 13 making relative movement to each other. The main scale 11 is formed out of a glass substrate 12. The encoder pattern 15 is formed on the glass substrate 12 by printing using a conductive paste compound for detecting the amount of relative displacement between the main scale 11 and the detection head 13 as an electric signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a displacement measuring instrument that measures a relative movement amount between a main scale and a detection head.
[0002]
[Background]
2. Description of the Related Art Conventionally, a capacitance type displacement measuring device including a main scale and a detection head that move relative to each other is known (for example, Patent Document 1).
In this conventional capacitance type displacement measuring instrument, an insulating glass epoxy substrate is used for the main scale, and the relative movement amount of both is based on the capacitance on the glass epoxy substrate in cooperation with the detection head. An encoder pattern to be detected as an electric signal is formed.
In creating this encoder pattern, a lithography method is used. In this method, first, for example, Cu (copper) is vapor-deposited or bonded to a copper thin film to form a thin-film electrode body on the main scale surface, and a resist is applied thereon. Then, after the mask having the encoder pattern is overlaid, the resist is exposed, developed, and then etched around so that a predetermined encoder pattern remains. Note that light (ultraviolet light, far ultraviolet light), electron beam, X-ray, or the like is used as an exposure means for exposing the resist.
An example of the encoder pattern is a wiring pattern as shown in FIG. The encoder pattern 60 is formed by coupling two loop portions 61 and 62 with a coupling loop 63.
[0003]
By the way, this type of capacitance type displacement measuring instrument is often used in the presence of cutting fluid (coolant) of a machine tool in a high temperature and high humidity environment such as a factory. Therefore, when an encoder pattern is formed of copper foil, there is a problem that the encoder pattern is corroded because it is exposed on the surface. Therefore, conventionally, for example, a liquid UV curable resin is applied on the encoder pattern to protect the encoder pattern, and a cover for protecting the surface is further provided thereon.
[0004]
[Patent Document 1]
JP-A-6-307802.
[0005]
[Problems to be solved by the invention]
However, the conventional capacitance displacement measuring instrument has the following problems.
First, since an insulating glass epoxy substrate is used for the main scale, it is easily affected by temperature changes, and high-precision measurement cannot be expected in an environment such as a factory.
Second, since the encoder pattern is formed by a lithography method, it is difficult to manufacture economically advantageous. In other words, the creation of the encoder pattern by lithography requires a lot of work processes, such as a resist coating process, a resist exposure process using light, a subsequent development process, and an etching process. There is a problem that it takes a lot of time and effort. In addition, when the encoder pattern is formed of copper foil, a portion other than the pattern is etched, resulting in a waste of material. In particular, when the pattern is, for example, in the form of a wiring, there is a problem that since the area to be etched is large, it takes a lot of time to finish the etching and many parts are wasted.
For the first problem, it is conceivable that the main scale is made of a material that is less affected by temperature change, for example, glass, but Cu (copper) is deposited to form a thin film electrode body on the glass. Since it is difficult to do this, there is a situation in which the conventional method has to rely on a lithography method.
[0006]
Third, to prevent the encoder pattern from being corroded, liquid UV resin is applied onto the encoder pattern and then covered with a cover to protect the surface. . In addition, when the main scale is long, a liquid UV curable resin must be applied over the entire length of the main scale, but it is difficult to apply uniformly over the entire length, and bubbles may be partially generated. The part which is not apply | coated may arise. As a result, corrosion starts from those portions, and accurate measurement may be hindered, and the life of the measuring scale is shortened.
[0007]
One object of the present invention is to provide a displacement measuring device that can simultaneously solve the first and second problems described above, that is, it is possible to always perform precise measurement without being affected by temperature changes, and to avoid waste of materials. It is another object of the present invention to provide a displacement measuring device that can easily form an encoder pattern.
[0008]
Another object of the present invention is to provide a displacement measuring instrument capable of reliably protecting an encoder pattern and extending its life.
[0009]
[Means for Solving the Problems]
The displacement measuring device according to claim 1, wherein the displacement measuring device is configured to include a main scale and a detection head that move relative to each other. The main scale is formed of a glass substrate, and cooperates with the detection head. An encoder pattern for detecting a relative displacement amount between the main scale and the detection head as an electric signal is formed on the glass substrate by printing using a conductive paste agent.
[0010]
According to such a configuration, since the main scale is formed of the glass substrate, accurate measurement is always possible without being affected by temperature changes during measurement. In addition, since the encoder pattern is formed on the main scale by printing using a conductive paste agent, it is only necessary to use the paste agent only on the necessary portion, that is, on the portion of the encoder pattern, thereby eliminating waste of materials. be able to. Furthermore, since the encoder pattern can be formed on the main scale by printing, it is possible to easily form the encoder pattern by omitting troublesome work such as vapor deposition of copper foil and etching work when creating by lithography. .
[0011]
In the present invention described above, the displacement measuring device is a capacitance type displacement measuring device that detects the relative displacement amount between the main scale and the detection head as an electric signal based on the capacitance from the encoder pattern, or based on an induced current. An electromagnetic induction displacement measuring device that detects as an electric signal is applied.
[0012]
The length measurement scale according to claim 2 is the length measurement scale according to claim 1, wherein the encoder pattern is formed by screen printing.
[0013]
According to such a configuration, an emulsion is applied to a screen used for screen printing, an encoder pattern mask is applied to the emulsion, exposed, developed, and then the emulsion is washed. Since the hole portion only needs to be filled with the paste agent, the encoder pattern can be easily printed with a simple apparatus and with little effort.
Further, if the paste agent is filled only in the hole portion, the encoder pattern can be formed, so that waste of material can be prevented.
[0014]
The displacement measuring device according to claim 3 is the displacement measuring device according to claim 1, wherein the encoder pattern is formed by a drawing device that injects the paste agent from a nozzle tip. is there.
[0015]
According to such a configuration, it is only necessary to inject the paste along the encoder pattern while controlling the nozzle. Therefore, the encoder pattern can be printed reliably and easily with little effort, and wasteful use of materials can be achieved. Can be prevented.
[0016]
The length measuring scale according to claim 4 is the displacement measuring instrument according to any one of claims 1 to 3, wherein the paste agent is a silver paste.
[0017]
According to such a configuration, since silver has a low electrical resistivity, the signal intensity of the encoder pattern can be increased by using such silver as a paste agent, and the measurement performance of the length measurement scale can be improved. Can be planned.
[0018]
The displacement measuring device according to claim 5 is the displacement measuring device according to any one of claims 1 to 4, wherein the entire surface of the main scale on which the encoder pattern is printed is covered with a UV curable sheet member. The UV curable sheet member is characterized in that it is integrally formed by applying a UV curable resin to one surface of a film-like resin.
[0019]
According to such a configuration, in order to protect the encoder pattern, the entire surface of the encoder pattern may be covered with the UV cured sheet member, so that even if the length measuring scale is long, it is easily covered without causing variations. Thus, the encoder pattern can be reliably protected, and the life of the main scale and thus the displacement measuring instrument can be extended.
Further, in order to protect the encoder pattern, the entire surface of the encoder pattern may be covered with a UV curable sheet member. Therefore, after applying a liquid UV curable resin, which has been performed by conventional surface protection, onto the encoder pattern, the cover is further covered. The encoder pattern can be easily protected because it does not require much time and effort such as covering the encoder pattern.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a schematic configuration of the displacement measuring instrument 10. The displacement measuring device 10 includes a main scale 11 and a detection head 13 and is an electromagnetic induction displacement measuring device.
The main scale 11 is formed of a glass substrate 12 having a predetermined plate thickness. An encoder pattern 15 is printed on the surface of the glass substrate 12 facing the detection head 13. This encoder pattern 15 is for detecting the relative displacement amount of the main scale 11 and the detection head 13 as an electrical signal based on the induced current in cooperation with the detection head 13.
The encoder pattern 15 is, for example, a wiring pattern similar to the wiring encoder pattern 60 shown in FIG. 6 described above, and is formed by screen printing in the first embodiment. Yes.
Further, the detection head 13 can be moved relative to the main scale 11.
[0021]
The wiring encoder pattern 15 is printed by screen printing as described above as shown in FIGS. 2A to 2D and FIGS. 3A to 3C.
That is, screen printing is performed using the screen frame 20. As shown in FIG. 2A, the screen frame 20 is formed by attaching a screen 22 to a frame 21 having a size covering the glass substrate 12, and an emulsion 23 is applied to the screen 22. Yes.
[0022]
As shown in FIG. 2B, a mask 25 on which the encoder pattern 15 is written is manufactured in advance for such a screen plate frame 20. As shown in FIG. 2C, after the mask 25 is overlaid on the emulsion 23 of the screen plate frame 20 and then baked by applying light from the mask 25 side, the emulsion 23A at portions other than the encoder pattern 15 is printed. Is cured. Next, when the development is performed, as shown in FIG. 2D, the cured portion of the emulsion 23A remains and the portion of the encoder pattern 15 where the emulsion 23 is washed away. 23B is formed.
[0023]
In order to print on the glass substrate 12 using the screen plate frame 20 formed as described above, the screen plate frame 20 is pressed against the surface of the glass substrate 12 as shown in FIG. Then, by sliding the squeegee 27, the silver paste 30 having a low resistivity is filled. At this time, the silver paste 30 fills the portion surrounded by the emulsion 23A remaining after curing, that is, the hole 23B along the shape of the encoder pattern 15, and when the operation is completed, the silver paste 30 is completely removed (see FIG. 3). As shown in B), when the screen frame 20 is removed, only the encoder pattern 15 remains on the surface of the glass substrate 12.
Thereafter, the encoder pattern 15 is dried to complete the creation of the main scale 11.
[0024]
Next, as shown in FIG. 3 (C), a UV curable sheet member 31 formed by applying a UV curable (ultraviolet curable) resin 33 to one side of a film-like resin 32 such as PET (polyethylene terephthalate) is used to make glass. The entire surface of the substrate 12 is covered to protect the encoder pattern 15.
As shown in FIG. 4, the UV curable sheet member 31 is attached to the back surface of the UV curable sheet member 31 formed corresponding to the length of the main scale 11 so that the encoder pattern 15 is completely covered. That's fine.
[0025]
According to the scale having the above configuration, the following effects are obtained.
(1) Since the main scale 11 is formed of the glass substrate 12, accurate measurement is always possible without being affected by temperature changes during measurement.
(2) Since the encoder pattern 15 is formed on the main scale 11 by printing using the conductive paste agent 30, the paste agent 30 may be used only in a necessary portion, that is, only in a portion of the encoder pattern 15. , Material waste can be eliminated.
[0026]
(3) Since the encoder pattern 15 can be formed on the main scale 11 by printing, troublesome work such as copper foil vapor deposition and etching when the encoder pattern is created by lithography can be saved. As a result, the encoder The pattern 15 can be easily formed.
[0027]
(4) Encoder pattern 15 is printed by screen printing. Emulsion 23 is applied to screen 22, mask 25 of encoder pattern 15 is applied to screen 22, exposed, developed, and then emulsion. Since the silver paste 30 may be filled in the hole 23B corresponding to the encoder pattern 15 formed by washing 23, the encoder pattern 15 can be easily printed with a simple device. In addition, it is only necessary to fill the silver paste 30 only in necessary portions, that is, only in the holes 23B along the encoder pattern 15, so that waste of material can be eliminated.
[0028]
(5) In order to protect the encoder pattern 15, the entire surface of the encoder pattern 15 may be covered with the UV curable sheet member 31, so that the displacement measuring instrument 10 can be easily covered even if it is long. As a result, the protection of the encoder pattern 15 can be reliably protected, and the life of the main scale 11 and thus the displacement measuring instrument 10 can be extended.
[0029]
(6) In order to protect the encoder pattern 15, the entire surface of the encoder pattern 15 may be covered with the UV cured sheet member 31, and thus liquid UV resin, which has been used in conventional surface protection, is applied onto the encoder pattern. Thereafter, it is possible to easily protect the encoder pattern 15 without much trouble such as further covering.
[0030]
(7) The silver paste 30 is used as the paste agent, and since silver has a low electrical resistivity, the signal intensity of the encoder pattern 15 can be increased by using such silver as the paste agent. The measurement performance of the measuring instrument 10 can be improved.
[0031]
Next, a second embodiment of printing according to the present invention will be described with reference to FIG.
Printing of the encoder pattern 15 in the first embodiment is performed by screen printing, but in the second embodiment, printing is performed by the printing machine 40.
That is, the printing machine 40 sandwiches the glass substrate 12 between the rotatable plate cylinder 41, the rubber cylinder 42 that contacts the plate cylinder 41 and rotates in opposite directions, and the rubber cylinder 42. The pressure plate 43 is configured to press the glass substrate 12 toward the rubber drum 42 side.
[0032]
The plate cylinder 41 is configured by, for example, winding a plate plate on which the encoder pattern 15 is formed. The plate cylinder 41 is pressed against the rubber cylinder 42 so that the encoder pattern 15 of the plate is transferred. Then, the encoder pattern 15 is transferred to the glass substrate 12.
The impression cylinder 43 sandwiches the glass substrate 12 rotatably with the rubber cylinder 42 and presses the glass substrate 12 toward the rubber cylinder 42.
[0033]
In order to print the encoder pattern 15 on the glass substrate 12 by the printing machine 40 as described above, the silver paste 30 is attached to the encoder pattern 15 of the plate of the plate cylinder 41, and the encoder pattern 15 is rotated by the rotation of the plate cylinder 41. The image is transferred from the plate cylinder 41 to the rubber cylinder 42, and transferred from the rubber cylinder 42 to the glass substrate 12 disposed between the rubber cylinder 42 and the impression cylinder 43.
Thereafter, the glass substrate 12 is removed, the encoder pattern 15 is dried, and the UV curable sheet member 31 is attached to the glass substrate 12. Such a glass substrate 12 is used as the main scale 11.
[0034]
According to 2nd Embodiment comprised as mentioned above, there exist the following effects other than the effect similar to said (1)-(3), (5)-(7).
(8) Since the glass substrate 12 is sandwiched between the rubber cylinder 42 and the impression cylinder 43, and the encoder pattern 15 can be printed on the glass substrate 12 by the rotation of each cylinder 41 to 43, the glass substrate 12 is continuously connected to many glass substrates. In addition, the encoder pattern 15 can be printed easily in a short time.
[0035]
It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
For example, in the first embodiment, the encoder pattern is printed by screen printing. In the second embodiment, the encoder pattern is printed by the printer 40, but the present invention is not limited to this. As long as the encoder pattern can be printed using the silver paste 30, it may be formed by a drawing apparatus that injects a paste agent from the nozzle tip, such as an ink jet method.
[0036]
In each of the above embodiments, the detection head 13 can be moved relative to the main scale 11. However, the present invention is not limited to this, and the main scale 11 can be moved relative to the detection head 13. May be.
[0037]
Further, in each of the above embodiments, the encoder pattern 15 is formed in a wiring shape, but is not limited thereto, and may have any shape.
Moreover, in each said embodiment, although the silver paste 30 excellent in electroconductivity and low resistivity is used as a paste agent, if it has the performance similar to the silver paste 30, another paste agent will be used. May be used.
[0038]
Further, the displacement measuring instrument 10 in each of the above embodiments is an electromagnetic induction displacement measuring instrument that detects the relative displacement amount between the main scale 11 and the detection head 13 as an electric signal based on the induced current from the encoder pattern 15. However, the present invention is not limited to this, and an encoder pattern of a type different from the encoder pattern 15 is used. From this encoder pattern, the relative displacement between the main scale 11 and the detection head 13 is detected as an electric signal based on the capacitance. You may apply to a capacitance type displacement measuring device.
[0039]
【The invention's effect】
As described above, according to the displacement measuring instrument of the present invention, since the main scale is formed of a glass substrate, accurate measurement can always be performed without being affected by temperature changes during measurement.
In addition, since the encoder pattern is formed on the main scale by printing using a conductive paste agent, it is only necessary to use the paste agent only on the necessary portion, that is, on the portion of the encoder pattern, thereby eliminating waste of materials. be able to.
Furthermore, since the encoder pattern can be formed on the main scale by printing, it is possible to easily form the encoder pattern by omitting troublesome work such as vapor deposition of copper foil and etching work when creating by lithography. .
[0040]
Further, according to the displacement measuring instrument of the present invention, in order to protect the encoder pattern, it is only necessary to cover the entire surface of the encoder pattern with the UV cured sheet member. Therefore, the encoder pattern can be surely protected, and the life of the main scale and thus the displacement measuring instrument can be extended.
Further, in order to protect the encoder pattern, the entire surface of the encoder pattern may be covered with a UV curable sheet member. Therefore, after applying a liquid UV curable resin, which has been performed by conventional surface protection, onto the encoder pattern, the cover is further covered. The encoder pattern can be easily protected because it does not require much time and effort such as covering the encoder pattern.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a displacement measuring instrument according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a screen printing procedure used in the embodiment, and showing a stage before shifting to printing.
FIG. 3 is a diagram showing a screen printing procedure used in the embodiment, and showing a stage before shifting to printing;
FIG. 4 is a perspective view showing a state in which the glass substrate of the embodiment is covered with a UV cured sheet.
FIG. 5 is a schematic view showing a printing machine according to a second embodiment for printing an encoder pattern on the displacement measuring instrument of the present invention.
FIG. 6 is a diagram illustrating an example of an encoder pattern.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Displacement measuring device 11 Main scale 12 Glass substrate 13 Detection head 15 Encoder pattern 20 Screen plate frame 23 Emulsion 25 Mask 30 Silver paste 31 which is a paste agent UV cured sheet member

Claims (5)

In a displacement measuring device configured to include a main scale and a detection head that move relative to each other,
The main scale is formed of a glass substrate,
An encoder pattern for detecting a relative displacement amount between the main scale and the detection head as an electric signal in cooperation with the detection head is formed on the glass substrate by printing using a conductive paste agent. A displacement measuring instrument. The displacement measuring instrument according to claim 1,
The displacement measuring instrument, wherein the encoder pattern is formed by screen printing. The displacement measuring instrument according to claim 1,
The encoder pattern is formed by a drawing device for injecting the paste agent from a nozzle tip. The displacement measuring instrument according to any one of claims 1 to 3,
The displacement measuring instrument, wherein the paste is a silver paste. The displacement measuring instrument according to any one of claims 1 to 4,
The entire surface of the main scale on which the encoder pattern is printed is covered with a UV curable sheet member, and this UV curable sheet member is integrally formed by applying a UV curable resin to one surface of a film-like resin. Displacement measuring instrument.

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