US-12625570-B2 - Electronic pen and core body for electronic pen including conductive core rod and protection member that covers core rod

US12625570B2US 12625570 B2US12625570 B2US 12625570B2US-12625570-B2

Abstract

An electronic pen includes a cylindrical housing including an opening on one end of the housing in an axial direction of the housing, a core body attached inside of the housing such that an end of the core body protrudes from the opening on the one end of the housing, and a signal generation circuit which, in operation, generates a signal that is transmitted from the core body. The core body includes a core rod that is conductive and a protection member. The core rod includes a front portion that protrudes from the opening on the one end of the housing, a back portion, and an intermediate portion between the front portion and the back portion. The intermediate portion has a tapered shape narrowing from the front portion toward the back portion. The core rod receives the signal from the signal generation circuit. The protection member covers a side surface of the intermediate portion of the core rod.

Inventors

Yoshiyuki Hashimoto
Shinya Aoki
Noboru Yamaguchi

Assignees

WACOM CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20240404
Priority Date: 20180913

Claims (14)

1 . An electronic pen comprising: a housing including an opening on one end of the housing in an axial direction of the housing; a core body attached inside of the housing such that one end of the core body protrudes from the opening on the one end of the housing; and a signal generation circuit which, in operation, generates a signal that is transmitted from the core body, wherein: the core body includes a core rod that is conductive and has a tapered shape that continuously narrows from the one end of the core body, which is located outside of the opening of the housing, toward another end of the core body, which is located inside of the housing, such that a cross-sectional dimension of the core rod at the one end is greater than a cross-sectional dimension of the core rod at the another end, the core rod receives the signal from the signal generation circuit, and the core body includes a protection member that covers the core rod.
2 . The electronic pen according to claim 1 , further comprising: a core body holding portion provided with the core body inside of the housing, wherein the protection member of the core body includes: a first protection portion that covers a front portion of the core rod, a second protection portion that covers an intermediate portion of the core rod excluding a part of the intermediate portion of the core rod that is adjacent to a back portion of the core rod, and a third protection portion that covers the part of the intermediate portion of the core rod that is adjacent to the back portion of the core rod and that forms a portion fitted to the core body holding portion.
3 . The electronic pen according to claim 2 , wherein: a maximum width of an end surface on a back end of the first protection portion in a direction crossing the axial direction is wider than a maximum width of an end surface on a front end of the second protection portion in the direction crossing the axial direction, and a maximum width of an end surface on a back end of the second protection portion in the direction crossing the axial direction is wider than a maximum width of an end surface on a front end of the third protection portion in the direction crossing the axial direction.
4 . The electronic pen according to claim 1 , wherein: the core rod and the protection member are formed by different materials, and the core rod is formed by a material that is softer than a material of the protection member.
5 . The electronic pen according to claim 4 , wherein: the material used to form the core rod is polyoxymethylene, felt, or an elastomer.
6 . The electronic pen according to claim 1 , wherein the one end of the core body is formed in a hemispherical shape or in a spherical shape or in a curved shape.
7 . The electronic pen according to claim 1 , wherein the core rod is cylindrical and the cross-sectional dimension of the core rod is a diameter of the core rod.
8 . A core body for an electronic pen, the electronic pen comprising a housing including an opening on one end of the housing in an axial direction of the housing, the core body being configured to be attached inside of the housing such that one end of the core body protrudes from the opening on the one end of the housing, wherein: the core body includes a core rod that is conductive and has a tapered shape that continuously narrows from the one end of the core body, which is located outside of the opening of the housing, toward another end of the core body, which is located inside of the housing, such that a cross-sectional dimension of the core rod at the one end is greater than a cross-sectional dimension of the core rod at the another end, the core rod is configured to receive a signal from a signal generation circuit provided inside of the housing; and the core body includes a protection member that covers the core rod.
9 . The core body for the electronic pen according to claim 8 , wherein: a core body holding portion is provided inside of the housing, and the protection member of the core body includes: a first protection portion that covers a front portion of the core rod, a second protection portion that covers an intermediate portion of the core rod excluding a part of the intermediate portion of the core rode that is adjacent to a back portion of the core rode, and a third protection portion that covers the part of the intermediate portion of the core rod that is adjacent to the back portion of the core rod and that forms a portion configured to be fitted to the core body holding portion.
10 . The core body for the electronic pen according to claim 9 , wherein: a maximum width of an end surface on a back end of the first protection portion in a direction crossing the axial direction is wider than a maximum width of an end surface on a front end of the second protection portion in the direction crossing the axial direction; and a maximum width of an end surface on a back end of the second protection portion in the direction crossing the axial direction is wider than a maximum width of an end surface on a front end of the third protection portion in the direction crossing the axial direction.
11 . The core body for the electronic pen according to claim 8 , wherein: the core rod and the protection member are formed by different materials, and the core rod is formed by a material that is softer than a material of the protection member.
12 . The core body for the electronic pen according to claim 11 , wherein: the material used to form the core rod is polyoxymethylene, felt, or an elastomer.
13 . The core body according to claim 8 , wherein the one end of the core body is formed in a hemispherical shape or in a spherical shape or in a curved shape.
14 . The core body according to claim 8 , wherein the core rod is cylindrical and the cross-sectional dimension of the core rod is a diameter of the core rod.

Description

BACKGROUND Technical Field The disclosure relates to an electronic pen used as a position indicator for a position detection apparatus mounted on an information processing apparatus, such as a tablet PC (Personal Computer), and to a core body for the electronic pen used for the electronic pen. Background Art A position detection apparatus and a position indicator are used as input devices of various electronic devices, such as a high-performance phone terminal called a smartphone and a tablet PC (Personal Computer). The position indicator is generally formed in a pen shape and is called an electronic pen, a stylus, or the like. There are various systems for the position detection apparatus and the position indicator. In a case of an active electrostatic system (AES) among these, a signal from an oscillation circuit mounted on the electronic pen is transmitted (emitted) from a nib toward a position detection sensor of the position detection apparatus to indicate the position on the position detection sensor. The position detection sensor used in the position detection apparatus of the active electrostatic system includes linear transparent electrodes arranged on a display screen of a display apparatus, such as an liquid crystal display (LCD), in an X-axis direction (horizontal direction) and a Y-axis direction (vertical direction) of the display screen. The position detection apparatus detects the position indicated by the electronic pen according to the position of the linear transparent electrode of the position detection sensor receiving the signal (electric field) emitted from the electronic pen. In the case of the electronic pen of the active electrostatic system, the signal from the signal generation circuit mounted on the electronic pen is transmitted from the nib as described above. Therefore, the core body of the electronic pen of the active electrostatic system of the related art is a columnar rod-shaped body, and the entire core body is formed by a conductive material. In the case of the electronic pen of the related art, when the nib is moved after the electronic pen is tilted, there is a problem that a waving phenomenon occurs in a reception signal detected by the position detection apparatus so that the linear characteristics of the detected indicated position become poor. This is caused by the fact that the signal (electric field) from the signal generation circuit is emitted not only from the nib (front end portion) of the core body of the electronic pen, but also from the axis part of the core body. That is, along with the movement of the electronic pen, the signal (electric field) emitted from the axis part of the core body is received by the linear transparent electrode of the position detection sensor. In this case, a strong signal is received when the axis part of the core body is on the transparent electrode, and a weak signal is received when the axis part is out of the transparent electrode. As a result, the waving phenomenon occurs in the reception signal received by the transparent electrode. This degrades the linear characteristics as detected characteristics of the indicated position when the electronic pen is tilted. Therefore, to improve the linear characteristics as detected characteristics of the indicated position, the front end portion of the core body may be formed into a sphere, and the axis part can be formed as thin as possible in the core body of the electronic pen of the active electrostatic system as disclosed in Japanese Patent No. 5761773 (hereinafter, referred to as Patent Document 1). The front end position of the core body is a sphere, and the axis part is thin. Therefore, even if the electronic pen is tilted, there is almost no influence of the signal (electric field) emitted from the axis part, and only the nib of the sphere is independently involved in the emission of the signal (electric field). The range of reception signal does not extend, and excellent linear characteristics can be obtained. A position detection system including the electronic pen and the position detection apparatus of the active electrostatic system may detect the tilt of the electronic pen and correct the parallax between the nib of the electronic pen and the indicated position of the display screen. That is, the indicated position on the display screen indicated by the nib of the electronic pen and the indicated position on the display screen detected by the position detection apparatus are misaligned in some cases. Therefore, if the tilt of the electronic pen can also be taken into account to bring the actual indicated position and the detected position into line with each other, the electronic pen becomes more useful. The tilt of the electronic pen is calculated based on the direction of the range of the reception signal at the time that the position detection sensor detects the signal (electric signal) emitted from the axis part of the core body when the electronic pen is tilted as