Electrostatic capacitance-type position detection device

In an electrostatic capacitance-type position detection device, a corresponding ground region is formed at an intersection point between a corresponding first virtual center line and a corresponding second virtual center line, and a corresponding detection electrode and a corresponding drive electrode are disposed on the outer side of the relevant ground region. The detection electrodes each include a first electrode line and a second electrode line that extend in a second direction and are disposed so as to sandwich therebetween the ground regions from a first direction. The drive electrodes are each configured by arranging electrode patterns in order in the first direction. The electrode patterns each include a third electrode line that extends in the second direction, and a fourth electrode line and a fifth electrode line that are located on both respective ends of the third electrode line and extend in the first direction.

CLAIM OF PRIORITY

This application claims benefit of priority to Japanese Patent Application No. 2014-037935 filed on Feb. 28, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an electrostatic capacitance-type position detection device that includes a contact surface, with which a pointing body such as a fingertip of an operator can come into contact, and detects the contact position of the pointing body on the contact surface.

2. Description of the Related Art

In recent years, along with the popularization of mobile terminals such as notebook-size personal computers (notebook PCs) and cellular phones, there have been used position input devices as operation devices. In many cases, the position detection devices each including a contact surface, with which a fingertip of an operator or the like can come into contact, and detecting the contact position of the fingertip or the like on the contact surface. The position input devices are commonly used for touch pads or the like for input to personal computers, and are also applied to touch panels of portable devices, various terminal devices, and so forth, using transparent substrates and transparent electrodes.

As such position input devices, there have been electrostatic capacitance-type position input devices that each detect the contact position of a fingertip on a contact surface, based on a change in electrostatic capacitance. In a case of utilizing one of the relevant position input devices as a device for moving a cursor, a user is able to move the cursor only by gently tracing the contact surface. Therefore, the position input devices are easy to use and preferred by many users. As the related art, there has been disclosed Japanese Unexamined Patent Application Publication No. 2013-222384.

In recent years, the electrostatic capacitance-type position detection devices mounted in notebook PCs and so forth have been desired to grow in size and be reduced in price. In order to satisfy such demands, it is desirable to increase the pitch of an electrode and to keep down the number of electrodes. However, there has been a problem that position detection accuracy is deteriorated if the pitch of an electrode is increased.

In an electrostatic capacitance-type position detection device including drive electrodes, detection electrodes, and ground electrodes, electrostatic capacitance between the corresponding drive electrode and the corresponding detection electrode is reduced by bringing a finger close thereto, and the reduction amount thereof is detected for each electrode, thereby detecting a position.

However, in such an electrostatic capacitance-type position detection device, there has been a problem that the point of intersection between the corresponding drive electrode and the corresponding detection electrode becomes a portion whose sensitivity is the highest and if the electrode pitch is increased, a sensitivity variation due to a position becomes large and position detection accuracy is deteriorated.

In addition, while largely functioning as a ground conductor for reducing electrostatic capacitance between the corresponding drive electrode and the corresponding detection electrode, the pointing body such as a finger also largely functions as a floating conductor that increases the electrostatic capacitance between the corresponding drive electrode and the corresponding detection electrode. This function as the floating conductor causes a detection error (inversion sensing error), and poses an obstacle to the enhancement of detection accuracy.

The present invention solves the above-mentioned problems, and provides an electrostatic capacitance-type position detection device capable of suppressing the variation of position sensitivity and the inversion sensing error and obtaining high position detection accuracy in a case of increasing the electrode pitch.

SUMMARY

An electrostatic capacitance-type position detection device includes a plurality of first electrodes arranged in parallel with one another in a first direction and disposed in a substrate so as to extend in a second direction perpendicular to the first direction, a plurality of second electrodes arranged in parallel with one another in the second direction on the substrate and disposed in the substrate so as to extend in the first direction, and a ground electrode disposed in the substrate, wherein one electrode out of each of the first electrodes and each of the second electrodes is electrically driven, an electric output of the other electrode is detected, and a position to which an object is close on the substrate is detected based on the detection result, wherein at an intersection point between a first virtual center line of each of the second electrodes, which is parallel to the first direction, and a second virtual center line of each of the first electrodes, which is parallel to the second direction, the ground electrode has a ground region within which the intersection point is located when the substrate is viewed in plan, the corresponding first electrode is disposed on an outer side of the ground region, and the corresponding second electrode is disposed on an outer side of the corresponding first electrode with respect to the corresponding intersection point.

According to this configuration, the ground region is formed in the above-mentioned intersection point and the corresponding first electrode and the corresponding second electrode are formed on the outer sides thereof. Therefore, it is possible to effectively inhibit the sensitivities of intersection points from becoming excessively high in such a manner as in the related art, and it is possible to effectively inhibit a sensitivity variation from occurring. In other words, according to this configuration, portions whose sensitivities are high are distributed around the individual intersection points. Therefore, even in a case where an electrode pitch is increased, it is possible to suppress a sensitivity variation due to a position, and it is possible to enhance position detection accuracy.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1is the configuration diagram of an electrostatic capacitance-type position detection device1according to an embodiment of the present invention.

In the present embodiment, an X direction and a Y direction are examples of a second direction and a first direction, respectively, of the present invention, a first virtual center line31is an example of a first virtual center line of the present invention, and a second virtual center line33is an example of a second virtual center line of the present invention.

In addition, detection electrodes5, drive electrodes7, and ground electrodes9are examples of first electrodes, second electrodes, and ground electrodes, respectively, of the present invention. In addition, ground regions19are examples of ground regions of the present invention. In addition, intersection points35are examples of intersection points of the present invention.

As illustrated inFIG. 1, in the electrostatic capacitance-type position detection device1, the detection electrodes5, the drive electrodes7, and the ground electrodes9are formed on the surface of an insulating substrate3. The electrostatic capacitance-type position detection device1is used for a touch pad or the like for input to a personal computer.

A coating layer17is formed on the detection electrodes5, the drive electrodes7, and the ground electrodes9, and the surface of the coating layer17is a surface17awith which a pointing body such as a finger based on an operator is to be in contact.

In addition, the electrostatic capacitance-type position detection device1includes a detection circuit11, a drive circuit13, and a decision circuit15.

In the electrostatic capacitance-type position detection device1, that the electrostatic capacitance of a position at which the pointing body such as a finger based on the operator is in contact with the surface17ais changed between before and after the contact is used, thereby detecting the contact position.

In other words, in the electrostatic capacitance-type position detection device1, the drive electrodes7are driven in order by the drive circuit13, and the voltages of the detection electrodes5are detected by the detection circuit11.

In addition, in the decision circuit15, one of the detection electrodes5, whose voltage change is detected by the detection circuit11, and one of the drive electrodes7, driven by the drive circuit13when the relevant voltage change is produced, are identified, thereby identifying the above-mentioned contact position of the surface17a.

The insulating substrate3utilizes an insulating synthetic resin material obtained by impregnating a glass woven fabric with an epoxy resin. The detection electrodes5, the drive electrodes7, and the ground electrodes9are formed of copper or a copper alloy and subjected to patterning using photolithography.

FIG. 2is the enlarged view of the vicinity of a portion surrounded by a dotted line II in the electrostatic capacitance-type position detection device1illustrated inFIG. 1.FIG. 3is a cross-sectional view taken along a cross-section line III-III illustrated inFIG. 2.

As illustrated inFIG. 1andFIG. 2, the detection electrodes5may be arranged in parallel with one another in the Y direction and formed on a surface3aof the insulating substrate3so as to extend in the X direction.

In addition, the drive electrodes7may be arranged in parallel with one another in the X direction and formed on the surface3aof the insulating substrate3so as to extend in the Y direction.

In addition, when viewed in plan, on the insulating substrate3, a first virtual center line31parallel to the Y direction with respect to each of the drive electrodes7and a second virtual center line33parallel to the X direction with respect to each of the detection electrodes5are specified.

The first virtual center line31is a line that passes through a plurality of intersection points35located in the Y direction at a same position in the X direction. The second virtual center line33is a line that passes through a plurality of intersection points35located in the X direction at a same position in the Y direction.

When the insulating substrate3is viewed in plan, the ground electrodes9may each include ground regions19within which the respective intersection points35are located, at the respective intersection points35between the respective first virtual center lines31and the corresponding second virtual center line33. In the example illustrated inFIG. 2, each of the ground regions19is a rectangle and the gravity center thereof is the corresponding intersection point35.

Each of the ground electrodes9may include a corresponding ground line21that connects the ground regions19adjacent to each other in the X direction and extends in the X direction.

As illustrated inFIG. 2, the detection electrodes5may be formed on the outer sides of the ground regions19. In addition, the drive electrodes7may be formed on the outer sides of the detection electrodes5with respect to the intersection points35.

The detection electrodes5may each include a first electrode line41and a second electrode line43that extend in the X direction and are formed so as to sandwich therebetween the ground regions19from the Y direction.

When viewed in plan, the first electrode line41and the second electrode line43are formed at a substantially equal distance from the rectangular outlines of the ground regions19in the vicinities of the ground regions19.

The first electrode line41and the second electrode line43, located on both sides of the corresponding ground region19in the Y direction, are formed so as to be line-symmetrical about the corresponding second virtual center line33that passes through the corresponding intersection point35within the relevant ground region19.

Here, the first electrode line41and the second electrode line43are examples of the first electrode line and the second electrode line, respectively, of the present invention.

A plurality of electrode patterns57may be arranged in order in the Y direction, thereby configuring each of the drive electrodes7.

Each of the electrode patterns57may be configured by a third electrode line51that extends in the X direction, and a fourth electrode line53and a fifth electrode line55that are located on both respective ends of the third electrode line51and extend in the Y direction.

Here, the corresponding third electrode line51may be formed between portions of the corresponding first electrode line41and the corresponding second electrode line43, which are parallel to the X direction and located between the two ground regions19adjacent to each other in the Y direction.

In addition, the corresponding fourth electrode line53and the corresponding fifth electrode line55may be formed so as to face portions of the corresponding first electrode line41and the corresponding second electrode line43, which are parallel to the Y direction.

Here, the third electrode line51, the fourth electrode line53, and the fifth electrode line55are examples of a third electrode line, a fourth electrode line, and a fifth electrode line, respectively, of the present invention. In addition, the electrode pattern57is an example of an electrode pattern of the present invention.

The third electrode line51, the fourth electrode line53, and the fifth electrode line55may be formed at a substantially equal distance from portions of the corresponding first electrode line41and the corresponding second electrode line43, located so as to face the third electrode line51, the fourth electrode line53, and the fifth electrode line55.

In addition, the respective electrode patterns57, located on both sides of the corresponding ground region19in the Y direction, are formed so as to be line-symmetrical about the corresponding second virtual center line33that passes through the corresponding intersection point35within the relevant ground region19.

Furthermore, portions of the first electrode line41and the second electrode line43surrounding the corresponding ground region19from the outside and the electrode patterns57located on the outer sides thereof may be formed so as to be line-symmetrical about the corresponding first virtual center line31that passes through the corresponding intersection point35within the relevant ground region19.

In a back surface3bof the insulating substrate3, sixth electrode lines59that each electrically connect the two fifth electrode lines55adjacent to each other in the Y direction may be formed. In other words, through-holes (not illustrated) are formed at the positions of both ends of the corresponding fifth electrode line55in the insulating substrate3, and the corresponding fifth electrode line55and the corresponding sixth electrode line59are electrically connected to each other through the through-holes. From this, an electric connection between the corresponding detection electrode5and the corresponding drive electrode7is avoided.

In the electrostatic capacitance-type position detection device1, the area of each of the ground regions19may be greater than the area of each of portions of the corresponding detection electrode5and the corresponding drive electrode7, the portions surrounding the corresponding ground region19. From this, it is possible to strengthen the function of the pointing body such as a finger as a ground conductor, and it is possible to make a function as a floating conductor relatively small. As a result, it is possible to make the inversion sensing error described in the related art smaller, and it is possible to enhance a detection sensitivity.

In addition, in order to reduce the influence of a noise, it is desirable to reduce the area of each of the detection electrodes5.

In addition, in a direction perpendicular to the surface3aof the insulating substrate3, the corresponding sixth electrode line59and the corresponding ground region19may be formed so as not to overlap with each other.

Hereinafter, the function of the electrostatic capacitance-type position detection device1illustrated inFIG. 1andFIG. 2will be described.

In the electrostatic capacitance-type position detection device1, in a case where the contact of the pointing body such as a finger based on the operator occurs on the surface17a, electrostatic capacitance between the corresponding detection electrode5and the corresponding drive electrode7in the vicinity of the corresponding intersection point35between the corresponding first virtual center line31and the corresponding second virtual center line33in the vicinity of the relevant contact position is reduced by the above-mentioned contact of the pointing body with the surface17a.

In the electrostatic capacitance-type position detection device1, the drive electrodes7are driven in order by the drive circuit13, and the voltages of the detection electrodes5are detected by the detection circuit11.

As described above, the electrostatic capacitance of the detection electrode5corresponding to the intersection point35located in the vicinity of a position on the surface17awith which the pointing body is in contact is reduced. Therefore, when the drive electrode7corresponding to the relevant intersection point35is driven, a voltage change corresponding to the above-mentioned reduction is generated in the corresponding detection electrode5.

At this time, the center of the corresponding ground region19is located at the corresponding intersection point35. Therefore, the detection sensitivity of the corresponding intersection point35does not become high locally.

In addition, in the decision circuit15, one of the detection electrodes5, whose voltage change is detected by the detection circuit11, and one of the drive electrodes7, driven by the drive circuit13when the relevant voltage change is produced, are identified, thereby identifying the above-mentioned contact position of the surface.

As described above, in the electrostatic capacitance-type position detection device1, the corresponding ground region19may be formed at the corresponding intersection point35between the first virtual center line31for specifying the center of the arrangement of the corresponding detection electrode5in the Y direction and the second virtual center line33for specifying the center of the arrangement of the corresponding drive electrode7in the X direction, and the corresponding detection electrode5and the corresponding drive electrode7may be formed on the outer side of the corresponding ground region19. Therefore, it is possible to effectively inhibit the sensitivities of intersection points from becoming excessively high in such a manner as in the related art, and it is possible to effectively inhibit a sensitivity variation from occurring. In other words, according to the electrostatic capacitance-type position detection device1, portions whose sensitivities are high are distributed around the individual intersection points35. Accordingly, it is possible to suppress a sensitivity variation due to a position, and it is possible to enhance position detection accuracy. Therefore, in a case where a coating layer formed on the detection electrodes5, the drive electrodes7, and the ground electrodes9is thin, it is possible to suppress a sensitivity variation, and it is possible to obtain high position detection accuracy.

In addition, in the electrostatic capacitance-type position detection device1, each of the detection electrodes5is formed between the corresponding ground region19and the corresponding drive electrode7. Therefore, it is possible to reduce an amount where an electric field generated from the drive electrodes7is absorbed by the ground regions19. From this, it is possible to improve a detection sensitivity.

In addition, in the electrostatic capacitance-type position detection device1, the area of each of the ground regions19may be made larger than the area of each of portions of the corresponding detection electrode5and the corresponding drive electrode7, the portions surrounding the relevant ground region19. From this, it is possible to strengthen the function of the pointing body such as a finger as a ground conductor, and it is possible to make a function as a floating conductor small. In addition, it is possible to make the inversion sensing error described in the related art smaller, and it is possible to enhance a detection sensitivity.

In addition, according to the electrostatic capacitance-type position detection device1, each of the detection electrodes5is formed on the inner side of the corresponding drive electrode7(on a side closer to the corresponding intersection point35). Accordingly, it is possible to reduce the area of each of the detection electrodes5, and it is possible to obtain a high noise resistance characteristic.

In addition, in the electrostatic capacitance-type position detection device1, the sixth electrode lines59that each electrically connect the two fifth electrode lines55adjacent to each other in the Y direction may be formed in the back surface3bof the insulating substrate3. By doing this way, it is possible to prevent the detection sensitivity of the intersection point35between the corresponding fifth electrode line55and the corresponding sixth electrode line59from becoming high locally. In other words, in a case where the corresponding drive electrode and the corresponding detection electrode are formed in the same surface of the substrate and the insulation layer is formed between the two electrodes, the sensitivity of the corresponding intersection point becomes high. On the other hand, in the present embodiment, it is possible to separate the corresponding fifth electrode line55and the corresponding sixth electrode line59from each other by the thickness of the insulating substrate3, and it is possible to prevent a sensitivity from becoming high locally.

In addition, in the configuration in which the insulation layer is formed in such a manner as described above, a variation in an electrostatic capacitance value is generated by the manufacturing variation of the insulation layer, and a characteristic is unstable. By forming the sixth electrode lines59in the back surface3bof the insulating substrate3in such a manner as in the present embodiment, it is possible to suppress such a manufacturing error.

In addition, in the electrostatic capacitance-type position detection device1, by connecting the end portions of the respective fifth electrode lines55of the two electrode patterns57adjacent to each other in the Y direction by the corresponding sixth electrode line59, it is possible to reduce the length of each of the sixth electrode lines59. From this, it is possible to reduce a decrease in detection accuracy due to a noise.

In addition, in the electrostatic capacitance-type position detection device1, only the sixth electrode lines.59of the drive electrodes7out of the detection electrodes5, the drive electrodes7, and the ground electrodes9may be formed in the back surface3bof the insulating substrate3, and the other configuration may be formed in the surface3a. Therefore, it is possible to bring the corresponding detection electrode5and the corresponding drive electrode7close to each other, and a sensitivity becomes high. In addition, it is possible to reduce wiring lines in the back surface3bof the insulating substrate3, and it is possible to reduce a noise received by the surface3afrom the back surface3b.

In addition, it is possible to increase the degree of freedom of the wiring lines in the back surface3bof the insulating substrate3.

FIG. 4is a diagram illustrating an electrode pattern of a second embodiment of the present invention.

As illustrated inFIG. 4, with the exception that the patterns of the detection electrodes and the drive electrodes are reversed with respect to the first embodiment, an electrostatic capacitance-type position detection device of the present embodiment is the same as that of the first embodiment.

As illustrated inFIG. 4, a plurality of detection electrodes105may be arranged in parallel with one another in the X direction and formed on the surface3aof the insulating substrate3so as to extend in the Y direction.

In addition, a plurality of drive electrodes107may be arranged in parallel with one another in the Y direction and formed on the surface3aof the insulating substrate3so as to extend in the X direction.

The ground electrodes9and the ground regions19are the same as those in the first embodiment.

As illustrated inFIG. 4, the drive electrode107may be located on the outer sides of the ground regions19. In addition, the detection electrodes105may be formed on the outer sides of the drive electrodes107with respect to the intersection points35.

The drive electrodes107each have the same pattern as that of the corresponding detection electrode5in the first embodiment. In addition, the detection electrodes105each have the same pattern as that of the corresponding drive electrode7in the first embodiment.

According to the second embodiment, from among the above-mentioned advantageous effects of the first embodiment, it is possible to obtain advantageous effects other than the advantageous effect based on it that the detection electrodes are formed on the inner sides of the drive electrodes.

FIG. 5is a diagram illustrating an electrode pattern of a third embodiment of the present invention.

The same entire configuration illustrated inFIG. 1applies to the present embodiment.

As illustrated inFIG. 5, a plurality of detection electrodes205may be arranged in parallel with one another in the Y direction and formed on the surface3aof the insulating substrate3so as to extend in the X direction.

In addition, a plurality of drive electrodes207may be arranged in parallel with one another in the X direction and formed on the surface3aof the insulating substrate3so as to extend in the Y direction.

In addition, when viewed in plan, on the insulating substrate3, a first virtual center line231parallel to the Y direction with respect to each of the drive electrodes207and a second virtual center line233parallel to the X direction with respect to each of the detection electrodes205are specified.

The first virtual center line231is a line that passes through a plurality of intersection points235located in the Y direction at a same position in the X direction. The second virtual center line233is a line that passes through a plurality of intersection points235located in the X direction at a same position in the Y direction.

In the present embodiment, each of ground electrodes209is formed by one ground region219. Each of the ground regions219may be formed so that the intersection points235located on the corresponding second virtual center line233are located therewithin. In the example illustrated inFIG. 5, each of the ground regions219is a rectangle.

As illustrated inFIG. 5, the detection electrodes205may be located on the outer sides of the ground regions219. In addition, the drive electrodes207may be formed on the outer sides of the detection electrodes205with respect to the ground regions219.

The detection electrodes205may each include a seventh electrode line241and an eighth electrode line243that are formed so as to surround the corresponding ground region219and extend in the X direction.

When viewed in plan, the seventh electrode line241and the eighth electrode line243may be formed at a substantially equal distance from the rectangular outline of the relevant ground region219in the vicinity of the relevant ground region219.

In addition, a plurality of ninth electrode lines245may be formed so as to be headed from the seventh electrode line241and the eighth electrode line243to the outer side of the ground region219.

The electrode patterns257may be arranged in order in the Y direction, thereby configuring each of the drive electrodes207.

Each of the electrode patterns257may be configured by a tenth electrode line251that extends in the X direction and a plurality of eleventh electrodes253,255, and257that extend from the tenth electrode line251in the Y direction.

Between the eleventh electrodes253,255, and257, at least portions of the respective ninth electrode lines245of the corresponding detection electrode205may be located.

In the back surface3bof the insulating substrate3, electrode lines259that each electrically connect the two eleventh electrode line255adjacent to each other in the Y direction may be formed. In other words, through-holes (not illustrated) are formed at the positions of both ends of the corresponding eleventh electrode line255in the insulating substrate3, and the two eleventh electrode lines255and the corresponding electrode line259are electrically connected to each other through the through-holes. From this, an electric connection between the corresponding detection electrode5and the corresponding drive electrode7is avoided.

According to the present embodiment, the same advantageous effects as those of the first embodiment are obtained.

The present invention is not limited to the above-mentioned embodiments.

In other words, regarding the configuration elements of each of the above-mentioned embodiments, those skilled in the art may perform various modifications, combinations, sub-combinations, and alternations within the technical scope of the invention or the equivalents thereof.

While, in the above-mentioned first embodiment, a case where the sixth electrode lines59that each electrically connect the two fifth electrode lines55adjacent to each other in the Y direction are formed in the back surface3bof the insulating substrate3is exemplified, the sixth electrode lines59may be formed in the surface3aof the insulating substrate3. In other words, formation by two layers may be adopted. In this case, an insulation layer is formed between the corresponding first electrode line41and second electrode line43and the corresponding sixth electrode line59.

In addition, the present invention may be applied to a case where the detection electrodes5,105, or205, the drive electrodes7,107, or207, and the ground electrodes9,109, or209are formed by three or more layers.

In addition, the shapes and the arrangements of the detection electrodes5,105, or205, the drive electrodes7,107, or207, and the ground electrodes9,109, or209, described above, are examples, and these are not limited in particular if falling within a scope identified by the invention of one of the attached Claims.

In addition, while, in the above-mentioned embodiments, a case where the present invention is applied to a touch pad or the like used for input to a personal computer, the present invention may be applied to another device, a touch panel, and so forth.