JPH1062110A - Electrostatic capacity type displacement detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacity type displacement detector wherein higher precision is intended by filling a through hole of a transmission electrode with a copper plating to reduce unbalance in transmission electrode output level. SOLUTION: With a through hole 17 of a transmission electrode 13 filled with a copper plating 18 by a single time of thick application or multiple times of application, the effect of turbulence in transmission electric field caused by the through hole 17 connecting the transmission electrode 13 with a backside wiring is made averaged among transmission electrode groups to which multiple kinds of transmission signals are given, for improved measurement precision in displacement detection. Assignment of through holes connecting the transmission electrodes with backside wirings can be set with less labor, for increased flexibility in wiring. Thereby, an electrostatic capacitive displacement detecting device of higher precision is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a capacitance type displacement detecting device.

[0002]

2. Description of the Related Art In a capacitive displacement sensor, a transmission electrode and a reception electrode are formed on a first scale and a second scale provided so as to be relatively movable, and the transmission electrode and the reception electrode are formed as the scale moves. The position measurement is performed by utilizing the change in the magnitude of the capacitive coupling between the two.
Japanese Patent Application Laid-Open No. 2-156519 is known. The capacitance type displacement sensor is configured as shown in FIG.

A slider 10 as a first scale and a second scale
The main scale 11, which is a scale of the above, is disposed so as to be relatively movable in the direction of the arrow. A plurality of transmitting electrodes 13 are arranged and formed on the slider 10 side, and a plurality of receiving electrodes 14 which are capacitively opposed to the transmitting electrode 13 are formed on the main scale 11 side. Also on the slider 10 side
A detection electrode 16 that is capacitively coupled to the reception electrode 14 is formed. The plurality of transmitting electrodes 13 are commonly connected, for example, every eight lines, so that eight types of AC signals having different phases by 45 ° are supplied.

FIG. 3A shows an arrangement pattern of transmission electrodes on the slider 10 side, and FIG. 3B shows a cross-sectional structure of one of these transmission electrodes. In such a sensor element or semiconductor element, a predetermined pattern is formed on the substrate by forming a thin-film electrode body by vapor-depositing a metal on the substrate surface, etching the electrode body appropriately, and etching the electrode body. Wiring is formed. When it is necessary to increase the mounting density, a three-dimensional pattern wiring is formed by laminating two or more pattern wirings as described above.

[0005] In this case, between the three-dimensionally intersecting layers,
It is indispensable to interpose an insulating protective layer such as glass epoxy or glass Teflon having high electrical insulation and environmental resistance. For example, a three-dimensional pattern wiring using two electrode layers on a substrate is formed. In this case, it is necessary to form a three-layer hierarchical structure of a first electrode body layer, an insulator layer, and a second electrode body layer, and to provide an insulator layer in a portion where wiring between upper and lower pattern wiring is required A through hole is formed and plated with copper to connect between the first and second electrode body layers.

The transmitting electrodes 13 are formed in a stripe shape having a constant width, and are arranged at a constant interval from each other. In the case of a small and high-resolution sensor, these transmitting electrodes 13 are formed with high precision using a lithography technique in a fine pattern, and through holes 17 are formed using a drill or the like. In FIG. 3A, the wiring 19 for commonly connecting every eight transmission electrodes 13 is shown as an equivalent circuit.
Actually, as shown in FIG. 3B, the potential of each transmission electrode 13 is applied through a copper portion plated around a through hole formed in each transmission electrode 13 by applying copper plating once. The module is miniaturized by being guided to the back surface of the slider substrate 12 and connected to the wiring 19 on the back surface of the substrate.

[0007]

In the case of a small capacitive displacement sensor, the area of the transmission electrode 13 is extremely small, and the through hole 17 for leading the transmission electrode 13 to the back surface of the substrate causes a measurement error. Become. That is, each transmission electrode 13
Is supplied with an AC signal to measure the magnitude of the capacitive coupling between the receiving electrode 14 and the opposing receiving electrode 14. When the transmitting electrode 13 is extremely small, the through hole 17 This causes disturbance of the uniformity of the transmission signal electric field formed from the surface, and the influence on the electric field distribution cannot be ignored. Further, if the through-hole 17 is further reduced, the yield is poor due to the difficulty in processing, and the cost is increased.

The arrangement pattern of the through-holes 17 illustrated in FIG. 3 is mainly designed to facilitate the routing of wiring on the back surface of the substrate. It has been clarified that an output level imbalance occurs between groups of transmitting electrodes to which alternating-current signals having different phases are applied, which causes a substantial variation in capacitance and causes a displacement measurement error. Deviation of capacitance variation error can be reduced by devising the arrangement of the through-holes to balance the output level of the electrodes. However, in practice, the layout of the through-holes was devised because there are many restrictions such as wiring routing. Just was not enough. The present invention has been made in view of such circumstances, and has as its object to reduce the imbalance in the transmission electrode output level by filling the through-holes of the transmission electrode with copper plating, and to improve the precision of the electrostatic. It is to provide a capacitive displacement detection device.

[0009]

According to the present invention, in order to achieve the above object, the first scale having a plurality of transmitting electrodes arrayed on a surface thereof is capacitively coupled to the transmitting electrode so as to face the transmitting electrode. The second scale on which a plurality of receiving electrodes are formed is disposed so as to be relatively movable, and the transmitting electrodes of the first scale are respectively led out to the back surface of the scale substrate through through holes, and the transmitting electrode is provided on this back surface. In a capacitive displacement detection device in which wiring for supplying a plurality of types of signals having different phases by common connection of a plurality of electrodes is provided, a transmission electrode output level of each group to which the plurality of types of signals are supplied The through-holes of the plurality of transmitting electrodes arranged and formed on the first scale are filled with copper plating so that the through-holes are equal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In all the drawings, components denoted by the same reference numerals represent the same components. FIG. 1A shows an arrangement pattern of transmission electrodes 13 of a slider 10 of a capacitive displacement sensor according to an embodiment of the present invention, and FIG. 1B shows a cross-sectional structure of one of the transmission electrodes 13. ing. The slider 10 is used as a first scale, and a main scale 11 (not shown) facing the first scale.
Is the same as that described with reference to FIG. 2 described above with reference to FIG. Transmission electrode 13
The detection electrode 16 is arranged adjacent to the array portion.

In the case of FIG. 1, 32 transmission electrodes 13 are formed on the surface of the slider substrate 12 in a fine stripe pattern and arranged at fine intervals. In order to connect these eight transmission electrodes 13 in common every eight electrodes, each transmission electrode 13 is guided to the back surface of the slider substrate 12 via a through hole 17. Although only an equivalent circuit is shown in FIG. 1, a wiring 19 for commonly connecting the transmission electrodes 13 is provided on the back surface of the slider substrate 12. Each transmitting electrode 13
As shown in FIG. 1A, the through holes 17 are mainly designed to facilitate the routing of wiring on the back surface of the substrate, and as shown in FIG. Is applied a plurality of times to fill the through holes 17. Alternatively, the through-hole 17 may be filled by applying the same thick plating once.

According to this embodiment, eight kinds of signals a, which are connected in common every eight lines and differ in phase by 45 °,
The effect of the through-hole 17 on the transmission signal becomes constant among the eight transmission electrode groups to which b,..., h are given. Thereby, the eight transmitting electrode groups and the receiving electrode 1
4, the variation in the capacitance measured between them is suppressed to be low, and highly accurate displacement measurement can be performed.

[0013]

As described above, according to the present invention, copper plating is applied a plurality of times or copper plating is applied once to fill the through hole of the transmission electrode, thereby connecting the transmission electrode to the back wiring. Since the influence of the disturbance of the transmission electric field due to the holes is made uniform among the transmission electrode groups to which a plurality of types of transmission signals are applied, the measurement accuracy of displacement detection is improved. Also, the layout of the through-holes that connect the transmission electrodes to the backside wiring can be set without any inconvenience, so there is a high degree of freedom in wiring. For this reason, it is possible to provide a capacitance-type displacement detection device with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a slider-side transmission electrode pattern and a cross-sectional structure of a capacitive displacement sensor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a conventional capacitance displacement sensor.

FIG. 3 is a diagram showing a conventional transmission electrode pattern and a cross-sectional structure.

[Explanation of symbols]

 Reference Signs List 10 slider 11 main scale 12 slider substrate 13 transmission electrode 14 reception electrode 16 detection electrode 17 through hole 18 copper plating 19 wiring

Claims (1)

[Claims] 1. A first scale having a plurality of transmitting electrodes arrayed on a surface thereof and a second scale having a plurality of receiving electrodes formed to face and capacitively couple with the transmitting electrodes are relatively movable. Disposed, each transmission electrode of the first scale is led out to the back surface of the scale substrate through a portion of copper plated around the through hole drilled respectively,
In the capacitance-type displacement detection device, on the back surface, a wiring for supplying a plurality of types of signals having different phases by connecting the transmission electrodes in common is provided. The through hole is filled with copper plating, and the through hole is filled.