1. A rotor for an electric motor with permanent magnets, said rotor having a principal axis (D), the rotor comprising:
a laminated core delimited by a first and a second end wall and by a lateral surface and having a hole for coupling to a motor shaft and a plurality of longitudinal slots for housing the magnets;
guide ribs in each of the slots for guiding the magnets in the slots; and
a flexural spring positioned between each magnet and the respective slot for stabilizing the magnets in the slots, wherein:
the core has a groove for each flexural spring,
the groove extends in a direction parallel to the principal axis (D) between the first and second end walls,
each spring is inserted lengthways in the groove, and
each groove is located at the midpoint of the respective slot, perpendicular to the respective slot;
wherein each slot has two end portions, one each on opposite ends of the slot, each end portion extending outward from the slot beyond one of the guide ribs;
wherein the lateral surface includes a plurality of straight portions, with each straight portion positioned radially outwardly of adjacent end portions of adjacent slots;
wherein radially inner edges and radially outer edges of adjacent end portions of adjacent slots, respectively, extend directly toward each other, and both the radially inner edges and the radially outer edges of the adjacent end portions are parallel to each other and also parallel to an adjacent straight portion of the lateral surface;
the laminated core further comprising a plurality of rectangular bonding elements for joining together laminations of the laminated core, each rectangular bonding element positioned radially inwardly of a pair of adjacent end portions and having radially inner and outer edges being parallel to the radially inner and outer edges of the adjacent end portions;
wherein the lateral surface is defined by a plurality of connected arcs each positioned at one of the longitudinal slots, the arcs having respective mid-points located at an equal distance (R1) from the principal axis (D) and centers positioned substantially at an internal edge of the hole.
2. The rotor according to claim 1, wherein the flexural spring operates in a direction (D1) that is substantially radial to the principal axis (D).
3. The rotor according to claim 1, wherein the ribs have a circular profile of radius (R) measuring between approximately 0.1 mm and approximately 0.5 mm.
4. The rotor according to claim 3, wherein the radius (R) measures approximately 0.2 mm.
5. The rotor according to claim 1, further comprising balancing holes that extend between the first and second end surfaces and are substantially parallel to the principal axis (D).
6. The rotor according to claim 5, further comprising balancing weights placed inside the holes.
7. The rotor according claim 1, wherein the rotor is a 4-pole rotor.
8. The rotor according to claim 7, wherein the arcs subtend an angle (H) of between approximately 55\xb0 and approximately 65\xb0 from the principal axis.
9. The rotor according to claim 8, wherein the arcs subtend an angle (H) of approximately 60\xb0 from the principal axis.
10. The rotor according to claim 8, wherein the arcs have a radius (R3) measuring between approximately 12 mm and approximately 15 mm, the magnets being between approximately 30 mm and approximately 50 mm in length (L1), between approximately 14 mm and approximately 16 mm in width (L2) and between approximately 2.5 mm and approximately 3.5 mm in height (L3).
11. The rotor according to claim 10, wherein the arcs have a radius (R3) measuring approximately 13.1 mm, the magnets being approximately 40 mm in length (L1), approximately 15.4 mm in width (L2) and approximately 3 mm in height (L3).
12. The rotor according to claim 1, wherein the the rotor is an 8-pole rotor.
13. The rotor according to claim 12, wherein the arcs subtend an angle (H) of between approximately 25\xb0 and approximately 35\xb0 from the principal axis.
14. The rotor according to claim 13, wherein the arcs subtend an angle (H) of approximately 30\xb0 from the principal axis.
15. The rotor according to claim 1, wherein the magnets consist of a plurality of portions housed side by side in the respective slot.
16. The rotor according to claim 1, wherein each of the magnets has a predetermined weight.
17. The rotor according to claim 1, wherein the first and second end walls are substantially parallel with each other, the laminated core comprising a plurality of laminations that are at least partially rotated relative to each other about the principal axis (D).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A display device that displays image information comprising:
a display panel which comprises:
a plurality of optical elements, each having a pair of electrodes including a first electrode, which is connected to a constant voltage source, and a second electrode, wherein each of the plurality of optical elements performs an optical operation according to a current passing between the first and second electrodes thereof;
a plurality of current lines;
a plurality of power lines, each of which is adapted to be charged with a first voltage during a selection time such that the power line does not allow a current to flow therethrough to an optical element, and to be charged with a second voltage during a non-selection time such that the power line allows a current to flow therethrough to an optical element;
a data driver that supplies a current having a current value obtained by adding a current value of an offset current to a current value of a drive current, wherein the current value of the drive current is set so as to accord to display data, and
wherein the display panel further comprises, for each of the optical elements:
a switch circuit that passes a write current with a predetermined current value through one of the current lines during the selection time and stops passing the write current during the non-selection time;
a current storage circuit which: (i) is connected to one of the power lines and to the second electrode of the optical element, (ii) stores current data according to the current value of the write current passing through the current line during the selection time, and (iii) supplies the drive current having a current value, which is obtained by subtracting a predetermined offset current from the current value of the stored write current, to the optical element during the non-selection time;
a drive control transistor including a control terminal, and a current path having a first end connected to said one of the power lines and a second end connected to the second electrode of the optical element;
a first capacitor device formed between the control terminal of the drive control transistor;
a write control transistor including a control terminal, and a current path having a first end connected to the control terminal of the drive control transistor and a second end connected to said one of the power lines; and
a second capacitor device formed between the control terminal of the write control transistor and one of the first and second ends of the current path of the write control transistor.
2. The display device according to claim 1, wherein the first capacitor device and the second capacitor device are connected to each other in series.
3. The display device according to claim 1, wherein the first capacitor device and the second capacitor device have a same capacitance value.
4. The display device according to claim 1, wherein the second capacitor device has a larger capacitance value than the first capacitor device.
5. The display device according to claim 1, wherein the switch circuit for each of the optical elements includes a current path control transistor in which a first end of a current path is connected to said one of the current lines and a second end of the current path is connected to the current storage circuit for the optical element, wherein the current path is made electrically conductive during the selection time, and the current path is made electrically non-conductive during the non-selection time.
6. The display device according to claim 1, wherein the first capacitor device includes a parasitic capacitance formed between the control terminal and the current path of the drive control transistor, and the second capacitor device includes a parasitic capacitance formed between the control terminal and the current path of the write control transistor.
7. The display device according to claim 1, wherein the drive control transistor and the write control transistor comprise amorphous silicon thin-film transistors.
8. The display device according to claim 1, wherein the optical elements comprise light-emitting devices.
9. The display device according to claim 1, wherein the optical elements comprise organic electroluminescence devices.
10. The display device according to claim 1, wherein a plurality of display pixels, each comprising one of the optical elements, the switch circuit for said one of the optical elements, and the current storage circuit for said one of the optical elements, are arrayed in a matrix form on the display panel.
11. The display device according to claim 1, wherein the display panel further comprises a plurality of scan lines to which selection signals are applied to select each said switch circuit and current storage circuit connected thereto.
12. The display device according to claim 11, further comprising a scan driver that applies the selection signals to the scan lines.
13. The display device according to claim 11, wherein the switch circuit for each of the optical elements includes a current path control transistor in which a first end of the current path is connected to said one of the current lines and a second end of the current path is connected to the current storage circuit for the optical element, and in which a control terminal of the current path control transistor is connected to one of the scan lines.
14. The display device according to claim 11, wherein in each said current storage circuit, the control terminal of the write control transistor is connected to one of the scan lines.
15. The display device according to claim 1, further comprising a power driver that applies the first voltage for supplying the write current to the current line, to the power lines during the selection time, and that applies the second voltage for supplying the drive current to the optical elements, to each of the power lines during the non-selection time.
16. The display device according to claim 15, wherein the first voltage is lower than a potential of the constant voltage source, and the second voltage is higher than the potential of the constant voltage source.
17. The display device according to claim 15, wherein during the non-selection time, the power driver applies voltage, which is between the control terminal of the drive control transistor and the first end of the current path, to each of the power lines such that the drive current passing through the drive control transistor becomes saturation current.
18. The display device according to claim 1, wherein the offset current is set according to variation in electrical potential of the control terminal of the drive control transistor based on a capacitance ratio between the first capacitor device and the second capacitor device.
19. The display device according to claim 1, wherein the offset current is set according to variation in electrical potential of the control terminal of the drive control transistor based on variation in electrical potential of the scan lines during the selection time and non-selection time.
20. A method for driving a display device that displays image information, wherein the display device comprises a display panel comprising:
a plurality of optical elements, each having a pair of electrodes including a first electrode, which is connected to a constant voltage source, and a second electrode, wherein each of the plurality of optical elements performs an optical operation according to current passing between the first and second electrodes thereof;
a plurality of current lines;
a plurality of power lines, each of which is adapted to be charged with a first voltage during a selection time such that the power line does not allow a current to flow therethrough to an optical element, and to be charged with a second voltage during a non-selection time such that the power line allows a current to flow therethrough to an optical element;
a switch circuit that passes a write current with a predetermined current value through one of the current lines during the selection time and stops passing the write current during the non-selection time;
a current storage circuit which: (i) is connected to one of the power lines and to the second electrode of the optical element, (ii) stores current data according to the current value of the write current passing through the current line during the selection time, and (iii) supplies the drive current having the current value, which is obtained by subtracting a predetermined offset current from the current value of the stored write current, to the optical element during the non-selection time; and
a data driver that supplies a current having a current value obtained by adding a current value of the offset current to a current value of the drive current, wherein the current value of the drive current is set so as to accord to display data, and
wherein each said current storage circuit comprises:
a drive control transistor including a control terminal, and a current path having a first end connected to said one of the power lines and a second end connected to the second electrode of the optical element;
a first capacitor device formed between the control terminal of the drive control transistor and one of the first and second ends of the current path of the drive control transistor;
a write control transistor including a control terminal, and a current path having a first end connected to the control terminal of the drive control transistor and a second end connected to said one of the power lines; and
a second capacitor device formed between the control terminal of the write control transistor and one of the first and second ends of the current path of the write control transistor;
wherein the switch circuit for each of the optical elements comprises a current path control transistor including a current path having a first end connected to said one of the power lines and a second end connected to the current storage circuit for the display element, wherein the current path is made electrically conductive during the selection time, and the current path is made electrically non-conductive during the non-selection time;
said method comprising:
a current storing step for a display element executed in the selection time for the display element, the current storing step including: (i) setting the first voltage across the power line connected to the switch circuit and the current storage circuit for the display element, (ii) activating the write control transistor to supply the write current to the current line from the data driver and to supply the write current through the current line to the current storage circuit, and (iii) storing a charge of the write current to the first and second capacitance elements so that the stored charge serves as the current data, and
a display step for the display element executed during the non-selection time for the display element, the display step including: (i) setting the second voltage across the power line connected to the switch circuit and the current storage circuit for the display element, (ii) deactivating the write control transistor to stop the supply of the write current to the current storage circuit, (iii) setting the offset current to a value determined by the change of electric potential of the control terminal of the drive control transistor caused in accordance with a difference between respective capacities of the first and second capacitance elements, and (iv) supplying the drive current with the current value, which is obtained by subtracting the value of the offset current from the stored current value of write current.
21. The method according to claim 20, wherein the drive current is supplied to the optical elements without passing through the current line in the display step.
22. The method according to claim 20, wherein the write current is supplied without passing through the optical element in the current storing step.
23. The method according to claim 20, wherein the first capacitor device includes a parasitic capacitance formed between the current path and the control terminal of the drive control transistor, and the second capacitor device includes a parasitic capacitance formed between the current path and the control terminal of the write control transistor.
24. The method according to claim 20, wherein the display panel further comprises a plurality of scan lines to which selection signals are applied to select each current storage circuit connected thereto, and wherein in each said switch circuit the control terminal of the current path control transistor is connected to one of the scan lines.
25. The method according to claim 20, wherein voltage to be applied to the power line during the non-selection time is charged with voltage, which is between the control terminal of the drive control transistor set by the voltage and one end of the current path, such that the drive current passing through the drive control transistor during the non-selection time becomes a saturation current by the voltage between the control terminal of the drive control transistor set by the voltage and said one end of the current path.