Position pointer of the electromagnetic induction type and electronic ink cartridge
A position pointer is disclosed, in which an electronic ink cartridge of an electromagnetic induction type is accommodated. The electronic ink cartridge includes a resonance circuit having a coil and a capacitor circuit, and is configured to detect pressure applied to a core member accommodated in the position pointer based on a variation of a resonance frequency of the resonance circuit. The cartridge includes a tubular member, in which the core member and the coil are accommodated such that the coil is positioned between the core member, which extends outwardly from one end of the tubular member, and the capacitor circuit along a direction of a center axis of the tubular member. The cartridge also includes a connection member in the tubular member, which electrically connects a first end and a second end of the coil to a first terminal and a second terminal of the capacitor circuit, respectively.
1. A pen-shaped position pointer, comprising:
a core having a distal end, which serves as a pointer tip, and a proximal end;
a resonance circuit comprised of a coil and a capacitor circuit that are connected in parallel with each other, wherein a characteristics of the resonance circuit changes in response to a pressure applied to the pointer tip of the core;
a first housing having an axis and a second housing having an axis that are detachably coupleable with each other along their axes, wherein the core is received in the first housing such that the pointer tip extends from a distal end of the first housing along its axis; and
a connection member received in the first housing adjacent to a proximal end of the first housing, wherein the connection member includes at least one terminal member having a distal end and a proximal end; wherein
the coil is disposed in the first housing between the core and the connection member along the axis of the first housing, one end of the coil is electrically connected to the distal end of the at least one terminal member, the proximal end of the at least one terminal member is exposed on the proximal end of the first housing;
the capacitor circuit is received in the second housing and the capacitor circuit includes at least one end, which is electrically connected with the exposed proximal end of the at least one terminal member of the first housing to form the resonance circuit when the first housing is coupled with the second housing along their axes; and
the exposed proximal end of the at least one terminal member is electrically disconnected from the at least one end of the capacitor circuit when the first housing is decoupled from the second housing.
2. The pen-shaped position pointer of claim 1 , wherein the first housing and the second housing are concentrically coupleable.
3. The pen-shaped position pointer of claim 1 , wherein the first housing and the second housing are coupleable via threads.
4. The pen-shaped position pointer of claim 1 , wherein the proximal end of the at least one terminal member and the at least one end of the capacitor circuit include a projection and a recess, or a recess and a projection, respectively, which are mateable when the first housing and the second housing are coupled with each other.
5. The pen-shaped position pointer of claim 1 , wherein the first housing is formed of nonmagnetic metal.
6. The pen-shaped position pointer of claim 1 , wherein the coil and the connection member are formed as a single module, which is receivable in the first housing.
7. The pen-shaped position pointer of claim 1 , wherein
the coil is wound around a first ferrite core;
a second ferrite core is disposed between the core and the coil, which is wound around the first ferrite core, in the first housing; and
an inductance of the coil changes according to a changing distance between the first ferrite core, around which the coil is wound, and the second ferrite core in response to a pressure applied to the pointer tip of the core.
8. The pen-shaped position pointer of claim 1 , wherein the core has a rod shape, and is replaceable via the distal end of the first housing from which the pointer tip extends.
9. The pen-shaped position pointer of claim 1 , wherein
the coil is wound around a ferrite core; and
the core integrally extends from the ferrite core toward and beyond the distal end of the first housing.
10. The pen-shaped position pointer of claim 1 , which forms an electronic ink cartridge when the first housing and the second housing are coupled with each other.
11. The pen-shaped position pointer of claim 10 , wherein an inner diameter of the electronic ink cartridge is about 1.5 mm to 2 mm.