JPH07225645A - Stylus for position input - Google Patents

Abstract

PURPOSE:To form sufficient electrostatic capacity between the conductive film of a face plate and a stylus and enable accurate position detection by providing a contact chip made of a conductive elastic material which is made thinner at the part corresponding to the flank part of the other end of a rod type conductor than at the tip part. CONSTITUTION:The contact chip 22 is made of the conductive elastic material which is made conductive by mixing carbon with an elastic material such as polyurethane. The contact chip 22 has a cavity part 24 which is larger or nearly as large as the head part of a screw 20 and also has one end made open and a flat tip part 28 formed at the other end. The cavity part 24 has an annular projection edge part 26 formed on its internal surface nearby the open end of the cavity part 24 in the circumferential direction. The tip part 28 of the contact chip 28 is made properly thick so as to provide sufficient elasticity since the entire area of the tip part 28 comes into nearly complete contact in conformity with the shape of the face plate when the contact chip 22 is pressed against the face plate. The flank part 30 of the contact part 22 is made as thin as possible to make an excellent electric connection between the flank part 30 and the head of the screw 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stylus for position input used for contacting a face plate in a capacitive touch panel device having a conductive face plate.

[0002]

2. Description of the Related Art A touch panel device is a data input device that allows an operator to interact with information displayed on the screen, and by touching a specific place on the screen, the touch screen device Displayed in different places,
You can select one of multiple computer command choices. The touch panel system includes a position measuring device that generates an address signal indicating a touched position. The address signal is sent to the computer, and the computer determines which of the command selection items has been selected based on the address signal. The object used by the operator to touch the display screen is called a stylus, and corresponds to, for example, the operator's finger, pen, or pencil.

A capacitance detection type touch panel device is provided with an optically transparent conductive film having a preselected resistivity and a face plate on which an insulating film is formed on the outer main surface. This face plate is arranged in front of the screen of the display device so that the operator can touch the insulating film at a position aligned with the information displayed on the screen. The operator typically touches the faceplate with his finger. At the position where the finger touches, capacitance is formed between the conductive film and the finger via the insulating film,
Current flows to the ground potential. The position of the finger on the face plate can be detected by measuring the current flowing through the conductive films on both sides divided at the position of the finger.

The capacitive touch panel device is widely used because of its simple structure, and is also used in various electronic measuring instruments. However, for example, a semiconductor device characteristic measuring instrument may be used in a clean room depending on the conditions such as the object to be measured.In that case, it is required to wear gloves, so it is possible to touch the face plate directly with your fingers. Can not. Therefore, in a clean room or the like, a stylus having a conductor at its tip and connected to the ground potential by a conductor is used. However, since contact between the stylus and the face plate having a curved surface is point contact, sufficient capacitance cannot be formed between the conductive film on the face plate and the stylus. Therefore, sufficient current does not flow, and accurate position detection cannot be performed.

Therefore, an object of the present invention is to provide a stylus for position input in a capacitive touch panel device, which forms a sufficient capacitance between the conductive film of the face plate and the stylus to enable accurate position detection. .

[0006]

In the position input stylus of the present invention, the rod-shaped conductor, one end of which is grounded through a conductive wire and the other end of which is internally threaded, is covered with an insulating outer cover. A screw is screwed into the other end of the rod-shaped conductor to form a conductive protrusion. The conductive protrusion is surrounded by a contact tip made of a conductive elastic material. The portion of the contact tip corresponding to the side surface of the screw is thinner than the portion corresponding to the tip of the screw. Thereby, the tip end of the contact tip and the rod-shaped conductor can be electrically excellently connected via the vicinity of the surface of the conductive elastic material having a high carbon content.

[0007]

1 is a cross-sectional view of a position input stylus of the present invention. The stylus body 10 includes, for example, a cylindrical rod-shaped conductor 12 made of a metal such as stainless steel, and an insulating outer cover 1 made of a plastic resin covering the rod-shaped conductor.
Including 4. At one end of the rod-shaped conductor 12, the female screw portion 1 is axially formed.
6 is formed, and a receptacle 18 which is a groove extending in the axial direction is formed at the other end. The diameter of the rod-shaped conductor 12 and the diameter of the outer cover 14 are, for example, 4 mm and 7.2 mm, respectively.

As with the rod-shaped conductor 12, the female screw portion 16 of the rod-shaped conductor 12 has a screw 2 made of a metal such as stainless steel.
0 is screwed in. The screw 20 is a threaded portion,
It consists of an intermediate portion having a diameter larger than that of the threaded portion and a head portion having a diameter larger than that of the intermediate portion, and when screwed in, the intermediate portion forms an annular recess. The diameter of the screw portion, the intermediate portion and the head portion of the screw 20 is, for example, 2 mm, 3.6 mm and 4.8 mm.

The contact tip 22 is made of a conductive elastic material in which carbon is mixed with an elastic material such as polyurethane or silicon to give conductivity. The contact tip 22 is a screw 20.
Has a hollow portion 24 of approximately the same size, one end is open, and a planar tip portion 28 is formed at the other end. In the vicinity of the open end of the hollow portion 24, an annular projecting edge portion 26 is formed on the inner surface along the circumferential direction. Screw 20 to contact tip 22
When inserted into the cavity 24 of the
Engages in the annular recess formed in the middle of the zero to prevent the contact tip 22 from coming off the screw 20 when the stylus is in use. The screw 20 is covered by the tip portion 28 and the side surface portion 30 of the contact tip 22. The diameter of the tip portion 28 is selected so that a sufficient capacitance is obtained between the tip portion 28 and the conductive film when the entire area of the tip portion 28 contacts the face plate, and the diameter is, for example, 4 mm.

The wall thickness of the tip portion 28 of the contact tip 22 is suitable so that when the contact tip 22 is pressed against the face plate, the entire region of the tip portion 28 follows the shape of the face plate and makes substantially complete contact. It should be thick and have sufficient elasticity. However, the conductive elastic member mixed with carbon has a manufacturing property that carbon is not uniformly distributed in the elastic member and its density becomes high near the surface. Therefore, if the wall thickness of the tip portion 28 is increased, the tip portion 28
The electrical connection between the screw 20 and the screw 20 is not sufficiently made. Therefore, by making the thickness of the side surface portion 30 of the contact tip 22 as thin as possible, a good electrical connection is made between the side surface portion 30 and the head of the screw 20. The material thicknesses of the tip portion 28 and the side surface portion 30 are, for example, 1.9 mm and 0.9 mm, respectively. In this case, it has been experimentally known that the resistance value between the central portion of the tip 28 of the contact tip 22 and the central portion of the tip of the screw portion of the screw 20 can be 100 ohms or less.

A receptacle 18 formed on the rod-shaped conductor 12.
The jack 32 connected to the other end of the electric cord 36 whose one end is grounded is inserted into this. Instead of grounding one end of the electric cord, it may be electrically connected to a part of the human body such as the wrist of the operator.

FIG. 2 is a sectional view showing a contact tip 22 'which is a modification of the contact tip 22 of the position input stylus of the present invention. In this variation, a gap 34 is provided between the tip 28 ′ of the contact tip 22 ′ and the head of the screw 20. Further, the thickness of the side surface portion 30 'of the contact tip 22' is the same as that of the side surface portion 30, but the thickness of the tip portion 28 'is equal to that of the tip portion 2'.
It is thinner than 8 and has the same thickness as the side surface portion 30 '. When this contact tip 22 'is pressed against the face plate,
The tip portion 28 'is dented while contacting the face plate, and a click feeling can be obtained. Further, when the contact tip 22 'is pressed against the face plate, the tip 28' is crushed and a wider contact area can be obtained.

Although the preferred embodiments of the present invention have been described above, it will be apparent to those skilled in the art that various modifications and changes can be made as necessary without departing from the spirit of the present invention. For example, the rod-shaped conductor 12 and the screw 20 may be integrally formed.

[0014]

According to the present invention, when a contact tip made of a conductive elastic member is pressed against a face plate,
The tip of the contact tip comes into close contact with the face plate, and a desired capacitance can be formed. In addition, since the thickness of the side surface of the contact tip surrounding the portion of the rod-shaped conductor protruding from the insulating outer layer is made thinner than the thickness of the tip, the tip of the contact tip passes through the vicinity of the surface with a high carbon content. Also, the rod-shaped conductor can be electrically connected well.

[Brief description of drawings]

FIG. 1 is a sectional view showing a position input stylus of the present invention.

FIG. 2 is a sectional view showing a modification of the contact tip shown in FIG.

[Explanation of symbols]

 12 Rod-shaped conductor 22 Contact tip

Claims (2)

[Claims] 1. A conductive member, one end of which is connected to a reference potential, the other end of which is surrounded, and a portion of the other end corresponding to a side surface portion is made thinner than a portion corresponding to a front end portion. A stylus for position input, comprising a contact tip made of an elastic material. 2. The position input stylus according to claim 1, wherein a gap is provided between the other end of the rod-shaped conductor and a portion of the contact tip corresponding to the other end.