A plurality of word lines (WL1) are provided in parallel to one another and a plurality of bit lines (BL1) are provided in parallel to one another, intersecting the word lines (WL1) thereabove. MRAM cells (MC2) are formed at intersections of the word lines and the bit lines therebetween. MRAM cells (MC3) are provided so that an easy axis indicated by the arrow has an angle of 45 degrees with respect to the bit lines and the word lines. Thus, an MRAM capable of cutting the power consumption in writing is achieved and further an MRAM capable of reducing the time required for erasing and writing operations is achieved.

1. Field of the Invention
The present invention relates to a magnetic memory device, and more particularly to a magnetic memory device having a nonvolatile memory cell array which uses a magnetic tunnel junction as each memory cell.
2. Description of the Background Art
 less than Tunnel Magnetic Resistance Effect greater than
A structure in which an insulative material is sandwiched between two ferromagnetic materials is termed xe2x80x9cmagnetic tunnel junction (MTJ)xe2x80x9d.
FIG. 67 shows a concept of an MTJ. In FIG. 67, an insulating layer TB is provided, being sandwiched between ferromagnetic layers FM21 and FM22 and a voltage is applied to the ferromagnetic layers FM21 and FM22.
In this structure, when a current tunneling the insulating layer TB is measured, it is observed that the measured current value varies depending on the directions of magnetization of the two ferromagnetic layers.
This phenomenon is termed xe2x80x9ctunnel magnetic resistance (TMR) effectxe2x80x9d. The TMR effect will be discussed, referring to FIGS. 68 to 70.
FIG. 68 is a schematic view showing the density of states N(E) of a transition metal. In FIG. 68, the horizontal axis indicates the density of states and the vertical axis indicates an energy E, and electrons included in atoms are grouped according to the directions of spin. Specifically, in FIG. 68, the density of states of atoms having electrons whose direction of spin is downward is shown on the left hand and that of atoms having electrons whose direction of spin is upward is shown on the right hand.
Further, in FIG. 68, since the atoms filled with electrons up to the Fermi level are schematically shown among the 3d orbit and the 4s orbit, the atoms filled with electrons up to the Fermi level are hatched with the Fermi level as the boundary.
The reason why the transition metal becomes a ferromagnetic substance is that the number of electrons whose direction of spin is downward and that of electrons whose direction of spin is upward are different on the 3d orbit among the atoms filled with electrons up to the Fermi level.
In other words, since number of electrons whose direction of spin is downward and that of electrons whose direction of spin is upward are equal on the 4s orbit, the electrons on the 4s orbit do not contribute to generation of magnetism.
FIGS. 69 and 70 are schematic views illustrating the TMR effect. In FIG. 69, among the 3d orbit of atoms constituting the ferromagnetic layer FM21 on the left side of the insulating layer TB, the density of states of atoms having the electrons of downward spin is higher than that of atoms having the electrons of upward spin and therefore the direction of magnetization is downward on the whole.
Similarly, the direction of magnetization of the ferromagnetic layer FM22 on the right side of the insulating layer TB is downward on the whole.
Tunneling of electrons mainly occurs so that the directions of spin in an initial state and a final state can be conserved. In the case of FIG. 69, since both the density of states of downward spin in the initial state (inside the ferromagnetic layer FM21) and that in the final state (inside the ferromagnetic layer FM22) are large, the tunneling probability is large and a tunneling current is also large. In other words, the tunnel magnetic resistance is small.
On the other hand, in FIG. 70, since the density of states of upward spin in the initial state (inside the ferromagnetic layer FM21) is large and that in the final state (inside the ferromagnetic layer FM22) is small, the tunneling probability is small and the tunneling current is also small. In other words, the tunnel magnetic resistance is large.
The tunnel magnetic resistance rate (TMRR) is expressed by the following equation;                     TMRR        =                                                            R                                  A                                                        xe2x80x83                                                      F                                            -                              R                F                                                    R              A                                =                                                    P                1                                                          P                2                                                    1              -                                                P                  1                                                                  P                  2                                                                                (        1        )
where the resistance in a case where the directions of magnetization of the two ferromagnetic layers are the same is RF and that in a case where those are opposite is RAF.
Further, in the above Eq. (1), P1 and P2 denotes the spin polarizabilities of the ferromagnetic layers FM21 and FM22, respectively.
Assuming that the density of states of xcfx81 spin band in the Fermi surface is D xcfx81 (EF), the spin polarizability is expressed as;                     P        =                                            D              ↑                              (                                  E                  F                                )                                      -                          D              ↓                              (                                  E                  F                                )                                                                        D              ↑                              (                                  E                  F                                )                                      +                          D              ↓                              (                                  E                  F                                )                                                                        (        2        )
Specifically, the spin polarizability becomes larger as the difference between the density of states of upward spin and that of downward spin is larger. Further, as the spin polarizability approximates 1, the TMRR becomes larger. Furthermore, it is known that the spin polarizability and the magnetization are in proportion to each other. Herein, the spin polarizabilities of various magnetic materials are shown in Table 1:
A device utilizing the above TMR effect to store data, making correspondence between the directions of magnetization of two ferromagnetic layers and two values, 0 and 1, is an MRAM (Magnetic Random Access Memory).
Accordingly, though it is required to change the direction of magnetization of one of the two ferromagnetic layers in the MTJ, in some cases, the directions of magnetization of both ferromagnetic layers are changed in the structure of FIG. 67 when the magnetic field is given thereto. Then proposed is a structure as shown in FIG. 71, in which an antiferromagnetic layer is formed on the one of the ferromagnetic layers to fix the direction of magnetization of the one of the ferromagnetic layers.
In FIG. 71, the insulating layer TB is sandwiched between the ferromagnetic layers FM21 and FM22 and an antiferromagnetic layer AF is formed above the ferromagnetic layer FM21. Further, a positive electrode of a DC power supply is connected to the antiferromagnetic layer AF and a negative electrode thereof is connected to the ferromagnetic layer FM22.
When a ferromagnetic material and an antiferromagnetic material are formed adjacently to each other, a magnetic flux penetrating these materials is closed to fix the direction of magnetization. This structure is termed xe2x80x9cspin valve type ferromagnetic tunnel junction elementxe2x80x9d.
FIG. 72 shows a structure of variation of the spin valve type ferromagnetic tunnel junction element. In FIG. 72, the insulating layer TB is sandwiched between the ferromagnetic layers FM21 and FM22, the antiferromagnetic layer AF is formed above the ferromagnetic layer FM21 and a ferromagnetic layer FM23 is formed below the ferromagnetic layer FM22.
Herein, the antiferromagnetic layer AF is made of, e.g., IrMn containing Ir (iridium) of 20 to 30 atom. %, to fix the direction of magnetization of the ferromagnetic layer FM21, and the ferromagnetic layer FM21 is made of CoFe having large coercivity because it is better that the direction of magnetization should be hard to reverse with respect to the external magnetic field.
Further, as discussed earlier referring to Eq. (1), since the tunnel magnetic resistance rate (TMRR) becomes larger as the spin polarizability is larger, CoFe is used as a material having large spin polarizability.
On the other hand, though the ferromagnetic layer FM22 is also made of CoFe, it is desirable that the ferromagnetic layer FM22 should be made of a material having small coercivity so that its direction of magnetization may be controlled by a smaller external magnetic field.
In the structure of FIG. 72, Ni80Fe20 (permalloy) having small coercivity and small spin polarizability is used as the ferromagnetic layer FM23 to allow easy reverse in the direction of magnetization of the ferromagnetic layer FM22. The direction of magnetization of the ferromagnetic layer FM22 can be thereby reversed by a small external magnetic field.
FIG. 73 shows a practical structure of the spin valve type ferromagnetic tunnel junction element of FIG. 72, and FIG. 74 shows measured characteristics of TMR in this structure.
In FIG. 73, the insulating layer TB is formed above a layered structure consisting of the antiferromagnetic layer AF and the ferromagnetic layer FM21 which are formed two-dimensionally on a substrate BD, and the ferromagnetic layer FM23 is formed above the insulating layer TB. A measured result of change in magnetic resistance MR at the time when the external magnetic field is given to such a structure is shown in FIG. 74.
In FIG. 74, the horizontal axis indicates the magnetic field (converted by 1 oersted=about 79 A/m) and the vertical axis indicates the tunnel magnetic resistance rate (TMRR). It can be seen from FIG. 74 that the TMRR is 36%, the magnetic field required to reverse the direction of magnetization is low, i.e., about 30 (xc3x9779 A/m), and a hysteresis symmetric with respect to the direction of magnetization is achieved.
 less than Structure and Operation Principles of MRAM greater than
In the MRAM, the directions of magnetization of the two ferromagnetic materials in the magnetic tunnel junction element making up a memory cell are controlled to be the same or opposite by the external magnetic field and the state where the directions of magnetization are the same or the state where the directions of magnetization are opposite is brought into correspondence with 0 or 1, to store data.
The stored data can be read out by passing a predetermined current through the memory cell and sensing the voltages at both ends of the tunnel magnetic resistance. Since sensing becomes easier as the tunnel magnetic resistance rate (TMMR) is larger, a ferromagnetic material having large spin polarizability is advantageous to the MRAM.
Further, in order to write data, it is only necessary to change the direction of magnetization of one of the ferromagnetic materials by using the magnetic field generated by passing a predetermined current through the lines (word line and bit line).
 less than Structure of MRAM Cell greater than
Now, discussion will be made below on a structure and an operation of an MRAM disclosed in U.S. Pat. No. 5,793,697 as a background-art example.
FIG. 75 is a perspective view showing an MRAM cell array and cells. In FIG. 75, word lines 1, 2 and 3 are provided in parallel to one another and bit lines 4, 5 and 6 are provided in parallel to one another, intersecting the word lines thereabove.
MRAM cells (hereinafter, sometimes referred to simply as xe2x80x9ccellxe2x80x9d) 9 are formed at intersections of the word lines and the bit lines therebetween. In FIG. 75, as shown in an enlarged view, the MRAM cell 9 has a structure in which a silicon pn-junction diode 7 and a magnetic tunnel junction element (MTJ) 8 are layered on the word lines.
FIG. 76 is a schematic view showing a cross-sectional structure of the MRAM cell 9. Further, FIG. 76 shows the MRAM cell 9 on the word line 3, where the word line 3 is provided on a silicon substrate 80 and thereon an n+ silicon layer 10 and a p+ silicon layer 11 are layered to make up the pn-junction diode 7. The pn-junction diode 7 is covered with an insulating film such as a silicon oxide film 13.
A tungsten stud 12 is formed above the pn-junction diode 7 and the pn-junction diode 7 is electrically connected to the MTJ 8 through the tungsten stud 12. Further, the silicon oxide film 13 is so provided as to also cover the tungsten stud 12 and surfaces of the tungsten stud 12 and the silicon oxide film 13 are planarized by CMP (Chemical Mechanical Polishing).
MTJ 8 has a layered structure consisting of a template layer 15 (having a film thickness of 10 nm) made of platinum (Pt), an initial ferromagnetic layer 16 (having a film thickness of 4 nm) made of permalloy of Ni81Fe19, a diamagnetic layer 18 (having a film thickness of 10 nm) made of Mn54Fe46, a ferromagnetic layer 20 (having a film thickness of 8 nm) made of permalloy of CoFe or Ni81Fe19 and having a fixed direction of magnetization, a tunnel barrier layer 22 made of Al2O3, a soft ferromagnetic layer 24 made of a multilayer film consisting of CoFe having a film thickness of 2 nm and Ni81Fe19 having a film thickness of 20 nm, and a contact layer 25 made of Pt from the bottom.
Further, the tunnel barrier layer 22 is formed by depositing Al having a film thickness of 1 to 2 nm and performing the plasma oxidation method for 60 to 240 seconds with the power density of 25 W/cm2 under the oxygen pressure of 100 mTorr (100xc3x9710xe2x88x923xc3x971.33xc3x97102Pa).
Furthermore, not shown in FIG. 76, a large MTJ is actually formed entirely over a surface of the silicon oxide film 13 on the substrate 80 and the MTJ is patterned by argon ion milling with a photoresist mask, to form a plurality of small MTJs 8 as shown in FIG. 76. Each MTJ 8 is covered with a silicon oxide film 26. Further, not shown in FIG. 76, the contact layer 25 is connected to the bit lines.
The magnetic tunnel resistance of the MTJ 8 varies depending on whether the direction of magnetization of the soft ferromagnetic layer 24 discussed above is the same as that of the ferromagnetic layer 20 or opposite to. The direction of magnetization of the soft ferromagnetic layer 24 can be changed by a magnetic field generated by a current flowing the bit lines and the word lines.
Further, the magnetic tunnel resistance of the MTJ 8 greatly depends on the film thickness and the barrier height of the tunnel barrier layer 22 and the material characteristics of a film, such as roughness, at an interface below the junction.
The soft ferromagnetic layer 24 is so formed as to have an easy axis which is a direction of easy magnetization. There are two directions of magnetization along the easy axis, corresponding to two data of the memory cell, 0 and 1, respectively.
On the other hand, the ferromagnetic layer 20 is formed so that its direction of magnetization should be the same as the easy axis of the soft ferromagnetic layer 24 and the direction should not be changed depending on the operating state of the MRAM.
Such a direction of magnetization is termed xe2x80x9cunidirectional anisotropy directionxe2x80x9d. The easy axis of the soft ferromagnetic layer 24 is defined by a combination of the intrinsic anisotropy, the stress induced anisotropy and an anisotropy which depends on shape of the MTJ 8.
The intrinsic anisotropy refers to an anisotropy of magnetization intrinsic to a ferromagnetic substance, and the stress induced anisotropy refers to an anisotropy of magnetization generated at the time when a stress is applied to a ferromagnetic substance.
Further, as shown in FIG. 75, the MTJ 8 has a rectangular shape with a long side L and a short side W in a plan view. This is because the easy axis of the soft ferromagnetic layer 24 is defined by using the anisotropy which depends on the shape of the MTJ 8.
Next discussion will be made on a method of setting the unidirectional anisotropy direction of the ferromagnetic layer 20. The initial ferromagnetic layer 16 deposited on the template layer 15 grows with a surface ({111} surface) whose crystal orientation is a {111} orientation upward. Further, the diamagnetic layer 18 made of MnFe is deposited on the initial ferromagnetic layer 16.
These magnetic layers are deposited under the magnetic field whose direction is the same as that of the easy axis of the soft ferromagnetic layer 24 which is deposited later, and the unidirectional anisotropy direction of the soft ferromagnetic layer 24 is thereby defined.
Further, since the magnetic flux is closed between the ferromagnetic layer 20 and the diamagnetic layer 18, the direction of magnetization of the ferromagnetic layer 20 becomes harder to change by the external magnetic field than that of the soft ferromagnetic layer 24, and the direction of magnetization of the ferromagnetic layer 20 is fixed within a range of magnitude of the magnetic field generated by the current flowing the word lines and the bit lines. Moreover, since the MTJ 8 has a rectangular shape in a plan view, a magnetizing anisotropy which depends on the shape of the ferromagnetic layer 20 is generated, which contributes to the stabilization in the direction of magnetization of the ferromagnetic layer 20.
 less than Outline of Writing/Reading Operation of MRAM greater than
Discussion will be made below on writing/reading operation of the MRAM.
When a predetermined current is passed through a word line and a bit line for address selection (referred to as xe2x80x9cselected word linexe2x80x9d and xe2x80x9cselected bit linexe2x80x9d), magnetic fields are generated around the lines and a coupled magnetic field obtained by coupling these magnetic fields is generated at an intersection (selected address) of these lines. When this magnetic field is given, the direction of magnetization of the soft ferromagnetic layer 24 in the MTJ 8 provided at the intersection of these lines is rotated in a surface of the layer, to write data.
The magnitude of the magnetic field is so designed as to be larger than that of a switching magnetic field (the magnetic field at which the direction of magnetization starts rotating) of the soft ferromagnetic layer 24, which mainly depends on the coercivity and the magnetizing anisotropy of the soft ferromagnetic layer 24.
Further, the magnetic fields generated around the selected word line and the selected bit line must be designed enough small to avoid rotation of the unidirectional anisotropy direction of the ferromagnetic layer 20. This is intended not to change the direction of magnetization of a half-selected cell. The half-selected cell refers to a cell in which the current flows in only one of the word line and the bit line which are provided thereabove and therebelow.
Thus, the architecture of the memory cell array is so designed as to avoid direct flow of the writing current into the MTJ 8, for the purpose of cutting the power consumption in data writing.
Further, the data written into the MRAM cell 9 are read out by sensing the current flowing vertically through the pn-junction diode 7 and the MTJ 8. Furthermore, since a tunneling current flows vertically through the MRAM cell 9 during operation, the occupied area of the MRAM cell 9 can be reduced.
The resistance of the tunnel barrier layer 22 made of Al2O3 in the MTJ 8 varies almost exponentially with respect to the film thickness thereof. Specifically, the current flowing in the tunnel barrier is reduced as the film thickness becomes thicker and only a current tunneling the junction flows vertically with respect to the junction.
The data in the MRAM cell 9 are read out by monitoring a voltage of the MRAM cell 9 generated when a sense current too much smaller than the writing current flows vertically in the MTJ 8.
As discussed earlier, the tunneling probability of the MTJ 8 increases as the density of states of the spin having the same polarity as the spin in the soft ferromagnetic layer 24 in the initial state is higher in the ferromagnetic layer 20 in the final state.
Accordingly, the magnetic tunnel resistance of the MTJ 8 is low when the states of spin of the soft ferromagnetic layer 24 and the ferromagnetic layer 20 are the same, in other words, the directions of magnetization of these layers are the same and is high when the directions of magnetization of these layers are opposite. Therefore, the data in the MRAM cell 9 can be read out only by monitoring the resistance of the MTJ with a microcurrent.
Further, the magnetic field generated by the sense current is negligible, which has no effect on the state of magnetization of the MRAM cell 9. Furthermore, since lines required for the reading/writing operation of the MRAM cell 9 are only the bit lines and the word lines shown in FIG. 75, an efficient memory cell array can be achieved.
 less than Writing Operation greater than
Further discussion will be made below on the writing operation of the MRAM, referring to FIGS. 77 and 78.
FIG. 77 is an equivalent circuit diagram of the MRAM cell array of FIG. 75, where both ends of the word lines 1 to 3 are connected to a word-line control circuit 53 and both ends of the bit lines 4 to 6 are connected to a bit-line control circuit 51. Further, for convenience of illustration in FIG. 78, the word lines 1 to 3 are represented as word lines WL1 to WL3 and the bit lines 4 to 6 are represented as bit lines BL4 to BL6 in some cases.
At the intersections of the word lines 1 to 3 and the bit lines 4 to 6 provided are the MTJs 8 represented by resistance symbols and the pn-junction diodes 7 represented by diode symbols.
Herein, assuming that the word line 1 and the bit line 4 are selected, an MRAM cell 9a located at the intersection of these lines is selected.
Writing to the selected MRAM cell 9a is performed by the coupled magnetic field generated by a current IB flowing in the bit line 4 and a current IW flowing in the word line 1.
A magnetic field generated by either one of the current IB and the current IW in the cell region is smaller than that required to change the direction of magnetization of the soft ferromagnetic layer 24 in the MTJ 8.
Therefore, in the MRAM cell arrays 9b to 9e which are half-selected cells (cells in which only one of the current IB and the current IW flows in the bit lines or the word lines), no writing operation is performed.
When the magnetic fields generated by the current IB and the current IW are coupled, however, the magnitude of the coupled magnetic field becomes enough large to change the direction of magnetization of the soft ferromagnetic layer 24 in the selected memory cell 9a.
Further, at least one of the current IB and the current IW is so designed as to flow bidirectionally in order to allow the direction of magnetization of the soft ferromagnetic layer 24 in the cell 9a to be two opposite ones. Furthermore, in FIG. 77, since two bit-line control circuits 51 and two word-line control circuits 53 are provided in pairs, both the currents IB and IW can change the directions of current flow.
FIG. 78 is a timing chart showing voltages and currents of the bit lines 4 to 6 (bit lines BL4 to BL6) and the word lines 1 to 3 (word lines WL1 to WL3).
As shown in FIG. 78, the voltages of the bit lines BL4 to BL6 in writing are set to a voltage Vb which is suitable for bidirectional currents. The voltages of the word lines WL1 to WL3 are set to a voltage Vw which is larger than the voltage Vb and positive.
On standby, these voltages are so set as to apply a reverse bias to the pn-junction diodes 7 in all the cells 9. Accordingly, neither the current IB nor the current IW flows in the memory cells on standby.
 less than Reading Operation greater than
Next discussion will be made on a reading operation of the MRAM in more detail, referring to FIGS. 77 and 78. As shown in FIG. 78, the voltage of the word line WL1 is lowered from Vw to Vb and the voltage of the bit line BL4 is raised from Vb to Vw, to apply a forward bias to the pn-junction diode 7 in the selected cell 9a.
In reading, the voltages of non-selected bit lines 5 and 6 are still the standby voltage Vb and those of the non-selected word lines 2 and 3 are still the standby voltage Vw.
Further, since there is no voltage drop from the word lines to the bit lines (in other words, 0 V is applied to the pn-junction diodes 7) in the half-selected cells 9b to 9e, no current flows in the cells.
The magnitude of a sense current 30 (see FIG. 77) flowing through the bit line BL4 and the cell 9a into the word line WL1 depends on the magnetic tunnel resistance of the selected cell 9a. In a sense circuit which is a constituent element of the bit-line control circuit 51, assuming that an average value of two current values estimated correspondingly to two states of the cell is defined as a reference current, the sense current is compared with the reference current. Then, the difference between the sense current and the reference current is amplified, to read data stored in the selected cell 9a.
Further, as shown by the waveform of the sense current 30 in FIG. 77, the sense current 30 has two kinds of current waveforms corresponding to two magnetic states of the MTJ 8.
After reading data, the voltages of the bit line BL4 and the word line WL1 are returned to the respective standby voltages, but the magnetic state of the memory cell 9a remains after the reading operation.
As discussed above, in writing data into the MRAM cell, the magnetic fields are generated by passing a current through the bit line and the word line. Since a magnetic field larger than the switching magnetic field of the soft ferromagnetic layer which is a constituent element of the cell has to be applied to the memory cell at the selected address, a relative large current is needed to flow. For this reason, the power consumption in writing disadvantageously becomes large.
Further, the background-art MRAM cell array has a problem that it takes long period of time to perform a batch erasing or a batch writing of data in a unit of memory block constituted of at least one memory cell array.
The present invention is directed to a magnetic memory device. According to a first aspect of the present invention, the magnetic memory device comprises a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix; a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; a plurality of first switching means connected to first ends of the plurality of bit lines, being capable of switching the electrical connection between the first ends and a first power supply or a second power supply; and a plurality of second switching means connected to second ends of the plurality of bit lines, being capable of switching the electrical connection between the second ends and the first power supply or the second power supply.
According to a second aspect of the present invention, in the magnetic memory device of the first aspect, the first switching means have first MOS transistors and second MOS transistors of the same conductivity type whose first main electrodes connected to the first ends of the plurality of bit lines, respectively, and second main electrodes connected to the first power supply and the second power supply, respectively, and the second switching means have third MOS transistors and fourth MOS transistors of the same conductivity type whose first main electrodes connected to the second ends of the plurality of bit lines, respectively, and second main electrodes connected to the first power supply and the second power supply, respectively.
According to a third aspect of the present invention, in the magnetic memory device of the first aspect, the first switching means have first MOS transistors and second MOS transistors of different conductivity types whose first main electrodes connected to the first ends of the plurality of bit lines, respectively, and second main electrodes connected to the first power supply and the second power supply, respectively, and the second switching means have third MOS transistors and fourth MOS transistors of different conductivity types whose first main electrodes connected to the second ends of the plurality of bit lines, respectively, and second main electrodes connected to the first power supply and the second power supply, respectively.
According to a fourth aspect of the present invention, in the magnetic memory device of the third aspect further comprises: fifth MOS transistors connected between the first main electrodes of the first and second MOS transistors, having the same conductivity type as that of the second MOS transistors; and sixth MOS transistors connected between the first main electrodes of the third and fourth MOS transistors, having the same conductivity type as that of the fourth MOS transistors, and in the magnetic memory device of the fourth aspect, control electrodes of the fifth and sixth MOS transistors are connected to a third power supply supplying a predetermined voltage which always brings an ON state.
According to a fifth aspect of the present invention, the magnetic memory device comprises: a plurality of memory cell arrays consisting of a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix, and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; and at least one memory cell array group having a plurality of main word lines provided across the plurality of memory cell arrays, and a plurality of memory cell array selecting lines provided correspondingly to the plurality of memory cell arrays, and in the magnetic memory device of the fifth aspect, the plurality of word lines are connected to outputs of first combined logic gates which are provided at intersections of the plurality of main word lines and the plurality of memory cell array selecting lines, respectively, and inputs of the first combined logic gates are connected to one of the plurality of main word lines and one of the plurality of memory cell array selecting lines which intersect each other.
According to a sixth aspect of the present invention, in the magnetic memory device of the fifth aspect, the at least one memory cell array group includes a plurality of memory cell array groups, the magnetic memory device further comprises: a plurality of global word lines provided across the plurality of memory cell array groups; and a plurality of memory cell array group selecting lines provided correspondingly to the plurality of memory cell array groups, in the magnetic memory device of the sixth aspect, the plurality of main word lines are connected to outputs of second combined logic gates which are provided at intersections of the plurality of global word lines and the plurality of memory cell array group selecting lines, respectively, and inputs of the second combined logic gates are connected to one of the plurality of global word lines and one of the plurality of memory cell array group selecting lines which intersect each other.
According to a seventh aspect of the present invention, the magnetic memory device comprises: a plurality of memory cell arrays consisting of a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix, and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; and at least one memory cell array group having a plurality of main bit lines provided across the plurality of memory cell arrays, and a plurality of memory cell array selecting lines provided correspondingly to the plurality of memory cell arrays, and in the magnetic memory device of the seventh aspect, the plurality of bit lines are connected to outputs of first combined logic gates which are provided at intersections of the plurality of main bit lines and the plurality of memory cell array selecting lines, respectively, and inputs of the first combined logic gates are connected to one of the plurality of main bit lines and one of the plurality of memory cell array selecting lines which intersect each other.
According to an eighth aspect of the present invention, in the magnetic memory device of the seventh aspect, the at least one memory cell array group includes a plurality of memory cell array groups, the magnetic memory device further comprises: a plurality of global bit lines provided across the plurality of memory cell array groups; and a plurality of memory cell array group selecting lines provided correspondingly to the plurality of memory cell array groups, and in the magnetic memory device of the eighth aspect, the plurality of main bit lines are connected to outputs of second combined logic gates which are provided at intersections of the plurality of global bit lines and the plurality of memory cell array group selecting lines, respectively, and inputs of the second combined logic gates are connected to one of the plurality of global bit lines and one of the plurality of memory cell array group selecting lines which intersect each other.
According to a ninth aspect of the present invention, the magnetic memory device comprises: a memory cell array consisting of a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix, and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; and an inductor, and in the magnetic memory device of the ninth aspect, the at least one magnetic tunnel junction has a soft ferromagnetic layer whose direction of magnetization is changeable, and the inductor generates a magnetic field along an easy axis which is a direction for easy magnetization of the soft ferromagnetic layer.
According to a tenth aspect of the present invention, in the magnetic memory device of the ninth aspect, the at least one magnetic tunnel junction is provided so that the easy axis coincides with a direction of extension of the plurality of bit lines or the plurality of word lines, and the inductor has a coil-like shape, being so provided along the direction of extension of the plurality of bit lines or the plurality of word lines which coincides with the easy axis, as to surround the memory cell array.
According to an eleventh aspect of the present invention, the magnetic memory device comprises: at least one memory cell array consisting of a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix, and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; and at least one flash bit line and at least one flash word line both having a flat-plate shape, being so provided outside the plurality of bit lines and the plurality of word lines in the at least one memory cell array, as to cover a formation region of the plurality of bit lines and the plurality of word lines.
According to a twelfth aspect of the present invention, in the magnetic memory device of the eleventh aspect, the at least one memory cell array includes a plurality of memory cell arrays, the plurality of memory cell arrays are provided in matrix, the at least one flash bit line and at least one flash word line include a plurality of flash bit lines and a plurality of flash word lines, respectively, which are provided in matrix along the arrangement of the plurality of memory cell arrays.
According to a thirteenth aspect of the present invention, the magnetic memory device comprises: at least one semiconductor chip; a shield body made of conductive material, for containing the at least one semiconductor chip; a package made of resin, for containing the shield body; a bottom-surface substrate for closing an opening of the package to seal the package; a signal transmitting bump provided in an outer main surface of the bottom-surface substrate, for transmitting a signal between the at least one semiconductor chip and the outside; and a shielding bump so provided as to surround the signal transmitting bump, being electrically connected to the shield body, and in the magnetic memory device of the thirteenth aspect, the at least one semiconductor chip includes a magnetic memory chip comprising a memory cell array which has a plurality of memory cells including at least one magnetic tunnel junction.
According to a fourteenth aspect of the present invention, the magnetic memory device of the thirteenth aspect further comprises: a first stress relieving film provided inside and outside an opening edge of the shield body; and a second stress relieving film provided on an inner wall of the shield body.
According to a fifteenth aspect of the present invention, in the magnetic memory device of the fourteenth aspect, the at least one semiconductor chip further includes a circuit chip including peripheral circuits of the memory cell array, and the magnetic memory chip and the circuit chip are contained in the shield body, being vertically layered.
According to a sixteenth aspect of the present invention, in the magnetic memory device of the thirteenth aspect, the at least one magnetic tunnel junction has a soft ferromagnetic layer whose direction of magnetization is changeable, and the shield body is made of ferromagnetic material having magnetic permeability equal to or higher than that of the soft ferromagnetic layer.
According to a seventeenth aspect of the present invention, in the magnetic memory device of the thirteenth aspect, the shield body is made of antiferromagnetic material.
According to an eighteenth aspect of the present invention, in the magnetic memory device of the thirteenth aspect, the shield body is made of multilayer film consisting of ferromagnetic material and antiferromagnetic material.
According to a nineteenth aspect of the present invention, the magnetic memory device comprises: a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix; and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction, and in the magnetic memory device of the nineteenth aspect, the plurality of memory cells are each provided between one of the plurality of bit lines and one of the plurality of word lines, the at least one magnetic tunnel junction has a soft ferromagnetic layer whose direction of magnetization is changeable, and the at least one magnetic tunnel junction is provided so that an easy axis which is a direction for easy magnetization of the soft ferromagnetic layer has an angle of 40 to 50 degrees with respect to the direction of extension of the plurality of bit lines and the plurality of word lines.
According to a twentieth aspect of the present invention, in the magnetic memory device of the nineteenth aspect, the magnetic tunnel junction has a rectangular shape in a plan view, whose side parallel to the easy axis is longer than a side perpendicular to the easy axis.
According to a twenty-first aspect of the present invention, the magnetic memory device comprises: a memory cell array consisting of a plurality of bit lines and a plurality of word lines, intersecting one another without being in contact to make up a matrix, and a plurality of memory cells provided at intersections of the plurality of bit lines and the plurality of word lines, including at least one magnetic tunnel junction; and at least one inductor and at least one capacitor provided at two ends, respectively, of at least one of the plurality of bit lines and the plurality of word lines, for conserving a current flowing in at least one of selected bit line and selected word line by LC resonant.
According to a twenty-second aspect of the present invention, in the magnetic memory device of the twenty-first aspect, the at least one inductor includes a plurality of inductors and the at least one capacitor includes a plurality of capacitors, the plurality of bit lines includes a plurality of bit line pairs of two bit lines, the plurality of inductors includes a plurality of first inductors so provided correspondingly to the plurality of bit line pairs, as to be electrically connected between the two bit lines, and the plurality of capacitors includes a plurality of first capacitors so provided at an end opposite to the end at which the plurality of inductors are provided, as to be electrically connected to the plurality of bit lines, respectively.
According to a twenty-third aspect of the present invention, in the magnetic memory device of the twenty-second aspect, the plurality of word lines includes a plurality of word line pairs of two word lines, the plurality of inductors includes a plurality of second inductors so provided correspondingly to the plurality of word line pairs, as to be electrically connected between the two word lines, and the plurality of capacitors includes a plurality of second capacitors so provided at an end opposite to the end at which the plurality of inductors are provided, as to be electrically connected to the plurality of word lines, respectively.
The present invention is also directed to a magnetic substrate. According to a twenty-fourth aspect of the present invention, the magnetic substrate at least has a multilayer film provided entirely on a main surface thereof, for making up at least one magnetic tunnel junction.
According to a twenty-fifth aspect of the present invention, in the magnetic substrate of the twenty-fourth, the multilayer film includes an antiferromagnetic layer, a ferromagnetic layer, a tunnel barrier layer made of insulative material and a soft ferromagnetic layer provided in this order as at least one magnetic tunnel junction.
According to a twenty-sixth aspect of the present invention, in the magnetic substrate of the twenty-fifth aspect, the multilayer film further includes a two-layered film consisting of a first conductivity type impurity layer and a second conductivity type impurity layer provided below the at least one magnetic tunnel junction, constituting a pn junction.
According to a twenty-seventh aspect of the present invention, in the magnetic substrate of the twenty-fourth aspect, the multilayer film is provided on a SOI substrate, the SOI substrate comprising: a substrate portion as a base; a buried oxide film provided on the substrate portion; and a SOI layer provided on the buried oxide film.
In the magnetic memory device of the first aspect of the present invention, since the first and second switching means allow the first and second ends of the bit line to be selectively connected to the first and second power supplies, it is possible to pass bidirectional currents through the bit line, changing the direction of magnetization of the magnetic tunnel junction, to allow writing and erasing of the data
In the magnetic memory device of the second aspect of the present invention, since the first and second switching means are constituted of the first to fourth MOS transistors of the same conductivity type, the manufacturing process becomes simple.
In the magnetic memory device of the third aspect of the present invention, since the first switching means is constituted of the first and second MOS transistors of different conductivity types and the second switching means is constituted of the third and fourth MOS transistors of different conductivity types, it is possible to eliminate the necessity of applying a voltage not lower than the power supply voltage to the control electrodes of one of the first and second MOS transistors and one of the third and fourth MOS transistors in an ON state and therefore the load on the gate insulating film becomes smaller.
In the magnetic memory device of the fourth aspect of the present invention, since the fifth and sixth MOS transistors which are always in the ON state are provided between the first main electrodes of the first and second MOS transistors and between the first main electrodes of the third and fourth first MOS transistors, the stress voltage on the first main electrode of one of the first and second MOS transistors and the stress voltage on the first main electrode of one of the third and fourth MOS transistors are reduced, and the leak current caused by the stress voltages can be reduced, to thereby cut the power consumption.
In the magnetic memory device of the fifth aspect of the present invention, in a case of the magnetic memory device having a plurality of memory cell arrays, since a plurality of main word lines across a plurality of memory cell arrays and a word line across a single memory cell array are used to reduce the number of memory cells connected directly to one line, the capacitance of load can be reduced. As a result, the delay time caused by the capacitance of load becomes shorter and a high-speed access can be thereby achieved.
In the magnetic memory device of the sixth aspect of the present invention, in a case of the magnetic memory device comprising a plurality of memory cell array groups each having a plurality of memory cell arrays, since a word line across a single memory cell array, a plurality of main word lines across a plurality of memory cell arrays and a plurality of global word lines across a plurality of memory cell array groups are used to reduce the number of memory cells connected directly to one line, the capacitance of load can be reduced. As a result, the delay time caused by the capacitance of load becomes shorter and a high-speed access can be thereby achieved.
In the magnetic memory device of the seventh aspect of the present invention, in a case of the magnetic memory device having a plurality of memory cell arrays, since a plurality of main bit lines across a plurality of memory cell arrays and a bit line across a single memory cell array are used to reduce the number of memory cells connected directly to one line, the capacitance of load can be reduced. As a result, the delay time caused by the capacitance of load becomes shorter and a high-speed access can be thereby achieved.
In the magnetic memory device of the eighth aspect of the present invention, in a case of the magnetic memory device comprising a plurality of memory cell array groups each having a plurality of memory cell arrays, since a bit line across a single memory cell array, a plurality of main bit lines across a plurality of memory cell arrays and a plurality of global bit lines across a plurality of memory cell array groups are used to reduce the number of memory cells connected directly to one line, the capacitance of load can be reduced. As a result, the delay time caused by the capacitance of load becomes shorter and a high-speed access can be thereby achieved.
Since the magnetic memory device of the ninth aspect of the present invention comprises the inductor which generates a magnetic field in a direction along the easy axis which is a direction for easy magnetization of the soft ferromagnetic layer, the batch erasing or batch writing of data in a plurality of memory cells each having at least one magnetic tunnel junction can be achieved, thereby allowing a short-time processing.
In the magnetic memory device of the tenth aspect of the present invention, since the magnetic field can be efficiently generated by the coil-shaped inductor, the power supply can be cut in batch erasing or batch writing of data in a plurality of memory cells.
In the magnetic memory device of the eleventh aspect of the present invention, since the flash bit line and the flash word line are provided outside a plurality of bit lines and a plurality of word lines in at least one memory cell array and the batch erasing or batch writing of data in a plurality of memory cells each having at least one magnetic tunnel junction can be performed by passing a current through the flash bit line and the flash word line in a predetermined direction, a short-time processing can be achieved.
In the magnetic memory device of the twelfth aspect of the present invention, in a case of the magnetic memory device comprising a plurality of memory cell arrays provided in matrix, since the flash bit line and the flash word line are so provided along the arrangement of a plurality of memory cell arrays as to make up a matrix and the batch erasing or batch writing of data in a plurality of memory cells can be thereby performed, a short-time processing can be achieved.
In the magnetic memory device of the thirteenth aspect of the present invention, since at least one semiconductor chip is contained in the shield body made of conductive material, it becomes possible, in a plurality of memory cells including at least one magnetic tunnel junction, to prevent reverse of the direction of magnetization of the magnetic tunnel junction by the external magnetic field, which causes rewriting of data.
In the magnetic memory device of the fourteenth aspect of the present invention, since the first and second stress relieving films hold at least one semiconductor chip, it is possible to reduce application of an external stress on a plurality of semiconductor chips.
In the magnetic memory device of the fifteenth aspect of the present invention, since two kinds of chips, the magnetic memory chip and the circuit chip including peripheral circuits of the memory cell array, are provided, these chips are separately manufactured, thereby eliminating the necessity for considering the difference in formation temperature and allowing optimization of the respective formation temperatures. Further, the manufacturing processes proceed in parallel, thereby cutting the manufacturing time.
In the magnetic memory device of the sixteenth aspect of the present invention, since the shield body is made of ferromagnetic material having magnetic permeability equal to or higher than that of the soft ferromagnetic layer, it is possible to effectively block off the external magnetic field.
In the magnetic memory device of the seventeenth aspect of the present invention, since the shield body is made of antiferromagnetic material, it is possible to effectively block off the external magnetic field.
In the magnetic memory device of the eighteenth aspect of the present invention, since the shield body is made of multilayer film consisting of the ferromagnetic material and the antiferromagnetic material, it is possible to effectively block off the external magnetic field.
In the magnetic memory device of the nineteenth aspect of the present invention, since at least one magnetic tunnel junction is provided so that the easy axis which is a direction for easy magnetization of the soft ferromagnetic layer may have an angle of 40 to 45 degrees with respect to the direction of extension of a plurality of bit lines and a plurality of word lines, the direction of magnetization of the soft ferromagnetic layer can be surely reversed with a small amount of writing current and the power consumption in a writing operation can be thereby reduced.
In the magnetic memory device of the twentieth aspect of the present invention, since the magnetic tunnel junction has a rectangular shape whose side parallel to the easy axis is longer than the side perpendicular to the easy axis in the plan view, it becomes easy to define the easy axis by the anisotropy which depends on the shape and it becomes possible to prevent a change of easy axis.
Since the magnetic memory device of the twenty-first aspect of the present invention comprises at least one inductor and at least one capacitor for conserving a current flowing in at least one of the selected bit line and the selected word line by LC resonant, the writing current can be recycled and the power consumption in a writing operation can be thereby cut.
In the magnetic memory device of the twenty-second aspect of the present invention, a specific structure to recycle the writing current in the bit line can be obtained.
In the magnetic memory device of the twenty-third aspect of the present invention, a specific structure to recycle the writing current in the word line can be obtained.
Since the magnetic substrate of the twenty-fourth aspect of the present invention at least has the multilayer film provided entirely on a main surface thereof to make up at least one magnetic tunnel junction, in manufacturing the magnetic memory device comprising the memory cells having at least one magnetic tunnel junction, the manufacturing process can be omitted and the manufacturing cost can be cut as compared with a case where a simple semiconductor substrate is prepared and the multilayer film is formed on a main surface thereof.
In the twenty-fifth aspect of the present invention, it is possible to obtain a magnetic substrate suitable to manufacture the magnetic memory device comprising a memory cell having a single magnetic tunnel junction.
In the twenty-sixth aspect of the present invention, it is possible to obtain a semiconductor substrate suitable to manufacture the magnetic memory device comprising a memory cell having a pn-junction diode below the single magnetic tunnel junction.
In the magnetic substrate of the twenty-seventh aspect of the present invention, since at least one magnetic tunnel junction is formed on the SOI substrate which reduces parasitic capacitance of a MOSFET, the operation speed of the MOSFET becomes high and consequently that of the magnetic memory device can becomes high.
A first object of the present invention is to provide an MRAM capable of cutting power consumption in writing.
A second object of the present invention is to provide an MRAM capable of cutting time required for erasing and writing operations.
These and other objects, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Magnetic memory device and magnetic substrate


An electronic device includes a display module, a supporting frame and a pivoting mechanism connected to the display module and the supporting frame. The display module can pivot relative to the supporting frame. The pivoting mechanism includes two fixing components connected to the display module, two shaft components passing through the supporting frame, two locating components respectively disposed on an inner side of the supporting frame, two resilient components, two pulling components and two cam components. An end of each resilient component is connected to the corresponding locating component. An end of each pulling component is connected to the other end of the corresponding resilient component. A side of each cam component is connected to the corresponding fixing component, and the other side of each cam component is connected to the corresponding shaft component. The other end of the pulling component winds around the corresponding cam component.

1. Field of the Invention
The present invention relates to an electronic device, and more specifically, to an electronic device with a pivoting mechanism capable of providing different torques.
2. Description of the Prior Art
In the modern society, an All-In-One PC becomes one of the most popular consumer electronic devices. The All-In-One PC often includes a touch display module, a pivoting mechanism and a supporting frame. The pivoting mechanism is connected to the supporting frame and the touch display module, so that the touch display module can pivot relative to the supporting frame. A user can push the touch display module to pivot relative to the supporting frame to adjust a view angle of the touch display module to meet the user's requirement. However, in a procedure of pivoting the touch display module relative to the supporting frame, because the torque provided by a torsion spring of the pivoting mechanism cannot be adjusted continuously according to a torque generated by the gravity of the touch display module, an unsmooth feeling of the user occurs in the procedure of pushing the display module. Therefore, it is an important issue to design a pivoting mechanism capable of facilitating the user to push the touch display module to pivot relative to the supporting frame smoothly.

Electronic device with a pivoting mechanism capable of providing different torques


A roller bearing unit having a rotating speed detector includes an outer race, an inner race, a cover made of synthetic resin, a sleeve made cylindrically of metal and a seal ring fitted in an engaging groove of an engaging portion of the cover. The seal ring is disposed between the inner surface of the outer race and the cover so as to prevent the entrance of muddy water into the unit.

The present invention relates to a rolling bearing unit having a rotating speed detector for rotatably supporting a wheel of an automobile by a suspension, and the rolling bearing unit having a rotating speed detector is used for detecting a rotating speed of the wheel.
A rolling bearing unit having a rotating speed detector is used for rotatably supporting a wheel of an automobile by a suspension and also used for controlling an anti-lock brake system (ABB) or a traction control system (TCS) by detecting a rotating speed of the wheel with the detector. Conventionally, various types of rolling bearing units having rotating speed detectors are well known. Each rotating speed detector incorporated into the rolling bearing unit includes a tone wheel, which is an element to be detected, rotated in conjunction with a wheel, and a sensor to output an output signal, the frequency of which changes in proportion to a rotating speed of the tone wheel. For example, a rolling bearing unit having a rotating speed detector shown in FIGS. 19 and 20 is described in the Technical Report No. 94-16051 by HATSUMEI KYOKAI, which is referred to as the first conventional example, hereinafter.
A hub 1 includes an inner race assembly. A flange 2 for fixing a wheel is formed on an outer circumferential surface of the outside end portion of the hub 1. The outside is defined as a side located outside of a vehicle with respect to the width direction of the vehicle when the rolling bearing is assembled into the vehicle. An inner raceway 3a and a step portion 4 are formed on an outer circumferential surface of the middle portion of the hub 1. Further, an inner raceway 3b is formed on an outer circumferential surface of the hub 1. In this way, an inner race 5 composing the inner race assembly in conjunction with the hub 1 is supported while an outer end surface of the inner race 5 is pushed against the step portion 4. In this connection, instead of directly forming the inner raceway 3a on the outer circumferential surface of the hub 1, another inner race (not shown) different from the hub 1 may be provided, and the inner race and the above inner race 5 may be outwardly engaged with the hub 1 so as to be fixed.
A male screw portion 6 is formed in a portion close to the inside end of the hub 1. The inside is defined as a side located inside of a vehicle with respect to the width direction of the vehicle when the rolling bearing is assembled into the vehicle. When a nut 7 is fastened to the male screw 6, the inner race 5 is fixed in a predetermined portion on the outer circumferential surface of the hub 1, so that the inner race assembly can be composed. An attaching portion 9 for fixing the outer race 8 to the suspension is formed on an outer circumferential surface of an outer race 8 arranged around the hub 1. Outer raceways 10a, 10b are formed on an inner circumferential surface of the outer race 8. The outer raceways 10a, 10b are respectively opposed to the inner raceways 3a, 3b. A plurality of rolling elements 11, 11 are installed between the inner raceways 3a, 3b and the outer raceways 10a, 10b. Due to the above arrangement, the hub 1 is capable of rotating inside the outer race 8. In this connection, in the example shown in FIGS. 19 and 20, balls are used for the rolling elements. However, in the case of a rolling bearing unit used for an automobile to which a heavy load is given, tapered rollers are used as the rolling elements in some cases. A seal ring 12 is fitted between the inner circumferential surface of the outside end portion of the outer race 8 and the outer circumferential surface of the hub 1. Since the seal ring 12 is arranged between the inner circumferential surface of the outer ring 8 and the outer circumferential surface of the hub 1, an outside and opening of the space in which the plurality of rolling elements are arranged is closed by the seal ring 12.
A base end portion of the tone wheel 13, that is, a left end portion of the tone wheel 13 shown in FIGS. 19, 20 is engaged with and fixed to and inside end portion of the inner race 5 which is a little distant from the inner raceway 3b. The entire tone wheel 13 is formed from a magnetic metal sheet such as a steel sheet into an annular shape (a short cylindrical shape). The tone wheel 13 is composed of a small diameter portion 14 and a large diameter portion 15 which are continuously connected to each other by a step portion 16, in which the small diameter portion 14 and the large diameter portion 15 are formed concentrically. The large diameter portion 15 of the tone wheel 13 is outwardly engaged with the outer circumferential surface of the end portion of the inner race 5, and the step portion 15 comes into contact with an end edge of the inner race 5. Under the above condition, the tone wheel 13 is supported by and fixed to the inner race 5. Therefore, the small diameter portion 14 is supported concentrically with the inner race 5. A plurality of through-holes 17 are formed in the small diameter portion 14 of the tone wheel 13 to serve as cutout portions on the rotational side. These through-holes 17 are formed in the circumferential direction at regular intervals. Accordingly, the magnetic characteristic of the tone wheel 13 is alternately changed in the circumferential direction at regular intervals. Shapes of the through-holes 17 are the same. Each through-hole 17 is formed into a rectangle, the long side of which is disposed in the axial direction, that is, the transverse direction in FIGS. 19 and 20.
An inside end opening of the outer race 8 is closed by a cover 18 formed into a cylindrical shape having a bottom from a metal sheet such as a stainless steel sheet or an aluminum alloy sheet by means of drawing. An annular synthetic resin member 21 which embeds an annular sensor 20 is fitted on an inner circumferential side of the cylindrical portion 19 composing the cover 18. The annular sensor 20 includes: a permanent magnet 22; a stator 23 composed of a magnetic member such as a steel sheet; and a coil 24. When these members 22, 23, 24 are embedded in the above synthetic resin 21, they are entirely formed into an annular shape.
In the above components of the sensor 20, the permanent magnet 22 is formed into an annular shape (ring shape) and magnetized in the diametrical direction. An inner circumferential surface of the permanent magnet 22 is opposed to a base end portion of the small diameter portion 14 of the tone wheel 13 while a minute clearance 25 is maintained between them. An outer circumferential surface of the portion of the tone wheel 13 in which the through-hole 17 is not formed is opposed to a base and portion of the small diameter portion 14 of the tone wheel 13 while a minute clearance is maintained between them. The stator 23 is entirely formed into an annular shape, the section of which is a substantial J-shape. An inner circumferential surface of the end portion of the outer diameter side cylindrical portion 26 composing the stator 23 is arranged close to or contacted with an outer circumferential surface of the permanent magnet 22. An inner circumferential surface of the inner diameter side cylindrical portion 27 composing the stator 23 is opposed to a portion of the tone wheel 13 in which the plurality of through-holes are formed. In the inner diameter side cylindrical portion 27, a plurality of cutout portions 28, which are stationary side cutout portions, are formed at regular intervals (central angle pitch), which are the same as those of the through-holes 17, in the circumferential direction of the inner diameter side cylindrical portion 27. Accordingly, the inner diameter side cylindrical portion 27 is formed into a comb-shape.
The coil 24 is formed into an annular shape in such a manner that a wire is wound around a bobbin made of nonmagnetic material. The coil 24 is arranged in a portion of the inner circumferential side 26 of the outer diameter side cylindrical portion 26 composing the stator 23. An electro-motive force generated in the coil 24 is taken out from a connector 30, which is a signal taking means, protruding from an outer surface of the cover 18.
In the rolling bearing unit having a rotating speed detector composed in the above manner, when the tone wheel 13 is rotated together with the hub 1, the magnetic flux density in the stator 23 opposed to the tone wheel 13 is changed, and the voltage generated in the coil 24 is changed at the frequency proportional to the rotating speed of the hub 1. The principle in which the voltage generated in the coil 24 is changed in accordance with a change in the magnetic flux flowing in the stator 23 is the same as the principle of the conventionally well known sensor used for detecting a rotating speed. The reason why the density of magnetic flux flowing in the stator 23 is changed in accordance with the rotation of the tone wheel 13 is described as follows.
Intervals of the plurality of through-holes 17 provided in the tone wheel 13 are the same as those of the cutout portions 28 provided in the stator 23. Accordingly, when the tone wheel 13 is rotated, each through hole 17 is opposed to each cutout portion 28 all over the circumference at one moment. At this moment when each through-hole 17 is opposed to each cutout portion 28, a pillar portion, which is a magnetic body, provided between the through-holes 17 adjacent to each other is opposed to a tongue member, which is a magnetic body, provided between the cutout portions 28 adjacent to each other. Under the condition that each pillar portion, which is a magnetic body, is opposed to each tongue member, which is also a magnetic body, a magnetic flux of high density flows between the tone wheel 13 and the stator 23.
On the other hand, when the phase of the through-hole 17 deviates from the phase of the cutout portion 28 by half the interval, the density of magnetic flux flowing between the tone wheel 13 and the stator 23 is lowered. In the above condition, the through-hole 17 provided in the tone wheel 13 is opposed to the tongue member, and at the same time the cutout portion 28 provided in the stator 23 is opposed to the pillar portion. A relatively large space between the tone wheel 13 and the stator 23 is formed all over the circumference under the above condition in which the pillar portion is opposed to the cutout portion 28 and the tongue member is opposed to the through-hole 17. Under this condition, the density of magnetic flux flowing between both members 13 and 23 is lowered. As a result, a voltage generated in the coil 24 is changed in proportion to the rotating speed of the hub 1. Due to the above action, the sensor 20 changes an output voltage generated in the coil 24 at the frequency proportional to the rotating speed of the hub 1.
However, in the rolling bearing unit having a rotating speed detector according to the first conventional example, the following problems may be encountered. In the first conventional example shown in FIGS. 19 and 20, the synthetic resin 21 in which the sensor 20 is embedded and the synthetic resin composing the connector 30 are disposed on both sides of the cover 18 made of a metallic sheet. Accordingly, the manufacturing work is complicated, and the cost is raised. That is, the rolling bearing unit having a rotating speed detector shown in FIGS. 19, 20 is manufactured as follows. First, the sensor 20 is embedded in the synthetic resin 21, and then the synthetic resin 21 is provided inside the cover 18. After that, under the condition that the cover 18 is set in the mold, injection molding is conducted to form the connector 30. Therefore, it is necessary to conduct the injection molding process twice. Alternatively, it is necessary to provide an adhesion process in which the synthetic resin 21 and the connector 30, which have been made by means of injection molding, are made to adhere to each other. As a result, the manufacturing cost is raised.
FIG. 21 is a view showing a rolling bearing unit having a rotating speed detector according to the second conventional example disclosed in Unexamined Japanese Patent Publication No. 63-166601.
The rotating wheel is composed of a hub 1 and an inner race 2. A flange 3 for fixing a wheel is formed in the outside end portion of the hub 1. An inner raceway 4a is formed in an outer circumferential surface of the middle portion of the hub 1. An inner raceway 4b is formed on an outer circumferential surface of the inner race 2. The inner race 2 is outwardly engaged with an outer circumferential surface of the middle portion of the hub 1. A male screw portion 5 is formed on an outer circumferential surface of the inside end portion of the hub 1. The male screw portion 5 is screwed to a nut 6. When the nut 6 is screwed to the male screw portion 5, an inside end surface of the inner race 2 is pushed, so that the inner race 2 can be fixed at a predetermined position on the outer circumferential surface of the hub 1.
A flange-shaped attaching portion 8 for supporting a suspension (not shown) is formed on an outer circumferential surface of the outer race 7 which is a stationary wheel. Two rows of outer raceways 9a, 9b are formed on an inner circumferential surface of the outer race 7. A plurality of rolling elements 10, 10 are formed between the outer raceways 9a, 9b and the inner raceways 4a, 4b. In this arrangement, the hub 1 is rotatably supported inside the outer race 7 supported by the suspension via the attaching portion 8.
The nut 6 includes a disk-shaped rotor 11. An irregular portion 12 is formed on the inside surface of the rotor 11. By the action of the irregular portion 12, the nut 6 generates a pulse-like output in a sensor 14 described later in accordance with the rotation of the hub 1. That is, the nut 6 functions as a tone wheel. A cover 13 is engaged with the inside opening of the outer race 7. The sensor is fixed to the cover 13, and an outside end surface of the sensor 14 is opposed to the irregular portion 12.
In the rolling bearing unit having a rotating speed detector described above, a wheel fixed to the flange portion 3 arranged in the outside end portion of the hub 1 can be rotatably supported by the suspension which holds the outer race 7. When the rotor 11 integrated with the nut 6 screwed to the inside end portion of the hub 1 is rotated in accordance with the rotation of the wheel, an output of the sensor 14 opposed to the irregular portion on the inside surface of the rotor 11 is changed. The frequency of a change in the output of the sensor 14 is proportional to the rotating speed of the wheel. Accordingly, when the output signal of the sensor 14 is inputted into a controller not shown in the drawing, it is possible to fince the rotating speed of the wheel. Therefore, ABS and TCS can be appropriately controlled.
In the conventional rolling bearing unit having a rotating speed detector composed as described above, an outside opening of the cover 13 which holds the sensor 14 with respect to the outer race 7 is tightly fitted into the inside opening of the outer race 7 in order to prevent the cover 13 from being carelessly disconnected from the outer race 7 by the vibration caused when the automobile is running.
However, when the cover 13 is tightly fitted into the outer race 7 as described above, it becomes difficult to separate both members 7, 13 from each other. When both members 7, 13 are forcibly separated from each other with a tool such as a driver, a strong force is given to the cover 13, and the cover 13 is deformed. As a result, it is impossible to use the cover 13 again. For this reason, when either the rolling bearing portion or the sensor 14 is out of order after the rolling bearing unit has been incorporated into an automobile and used over a long period of time, the entire rolling bearing unit having a rotating speed detector must be also replaced, that is, a portion which is in good order must be replaced. This causes a raise in the maintenance cost. From the viewpoint of economizing resources, such a case is not preferable.
In view of the above circumstances, in order to detach the cover 13 from the outer race 7 easily, Unexamined Japanese Utility Model Publication No. 5-14634 discloses a rolling bearing unit having a rotating speed detector as shown in FIG. 22, which is referred to the third conventional example. In the rolling bearing unit having a rotating speed detector, a flange portion 3 for fixing a wheel is formed on an outer circumferential surface of the outside end portion of the hub 1 composing a rotating wheel in conjunction with the inner race 2. An inner raceway 4a and a step portion 15 are formed on an outer circumferential surface of the middle portion of the hub 1. In the inner race 2 having the inner raceway 4b which is formed on the outer circumferential surface of the hub 1, an outside end surface of the inner race 2 is confronted with the step portion 15 so that the inner race 2 is outwardly supported to the outer circumferential surface of the hub 1.
A male screw portion 5 is formed on an outer circumferential surface of the inside end portion of the hub 1. When a nut 6 is fastened to the male screw portion 6, the inner race 2 is fixed in a predetermined portion on the outer circumferential surface of the hub 1. An irregular portion 16 is formed on an outer circumferential surface of the nut 6. Therefore, the nut 6 functions as a tone wheel for detecting a rotating speed of the nut 6. An attaching portion 8 for fixing the outer race 7 to the suspension is formed on an outer circumferential surface of the outer race 7. A pair of outer raceways 9a, 9b are formed on an inner circumferential surface of the outer race 7 and are respectively opposed to the inner raceways 4a, 4b. A plurality of rolling elements 10, 10 are installed between a pair of inner raceways 4a, 4b and a pair of outer raceways 9a, 9b so that the hub 1 can be freely rotated inside the outer race 7. A seal ring 17 is fitted between the inner circumferential surface on the outside end portion of the outer race 7 and an outer race circumferential surface of the hub 1. Further, a seal ring 17 is fitted between the inner circumferential surface on the inside end portion of the outer race 7 and an outer circumferential surface of the inner race 2. That is, the seal ring 17 exists between the inner circumferential surface of the outer race 7 and the outer circumferential surface of the hub 1, and also the eal ring 17 exists between the inner circumferential surface of the outer race 7 and an outer circumferential surface of the inner race 2. The seal rings 17 close openings on both side end portions of the space in which the plurality of rolling elements are accommodated.
A portion of the opening of the inside end portion (the right end portion in FIG. 22) of the outer race 7 is closed by a cover 18. The entire cover 18 is formed into an annular shape by press-forming a metallic sheet. The shape of the cover 18 is described as follows. In order to insert a portion of a constant velocity joint inside the cover 18 in the diametric direction, an outer periphery of the base plate portion 19 formed into an annular shape is bent at a right angle to the outside (to the left in FIG. 22), so that a cylindrical vertical wall 20 can be formed. Further, an annular step portion 21 is formed on an outer circumferential periphery of the opening of the outside end (the left end in FIG. 22) of the vertical wall 20 so that the annular step portion 21 is capable of being freely confronted with the inside end surface 7a of the outer race 7.
When an outer circumferential edge of the step portion 21 is bent outwardly at a right angle, an engaging cylindrical portion 22 capable of engaging with the inside end portion of the outer race 7 is formed. When an outside end opening of the engaging cylindrical portion 22 is bent outwardly in the diametric direction by an angle of 180, an engaging portion 23, the size in the diametric direction of which is large, is formed. The cover 18 is fixed to the outer race 7 in such a manner that the engaging cylindrical portion 22 is outwardly engaged with the inside end portion of the outer race 7, and at the same time the step portion 21 is confronted with the inside end surface 7a of the outer race 7. The engaging strength of the engaging cylindrical portion 22 and the inside end portion of the outer race 7 is determined to be a sufficiently high value so that the outer race 7 and the cover 18 can not be disconnected from each other by the vibration caused when the automobile is running. For example, an electromagnetic sensor 14 is fitted inside the cover 18 and an output of the sensor 14 is sent to a controller (not shown) via a lead wire 24.
Substantially in the same manner as that of the rolling bearing unit having a rotating speed detector shown in FIG. 21, by the above rolling bearing unit having a rotating speed detector, the wheel is rotatably held with respect to the suspension, and the rotating speed of the wheel fixed to the flange portion 3 of the hub 1 can be detected. Especially, when it becomes necessary to disconnect the cover 18 from the outer race 7 for the purpose of maintenance in the arrangement shown in FIG. 22, as shown by a chain line in FIG. 22, an inner circumferential edge of a tool 25 such as a hand press or a pulley extractor having an engaging portion of split structure is engaged with an edge of the engaging portion 23 formed in the outer circumferential edge of the outside end opening of the cover 18. When the tool 25 is displaced in a direction in which the tool 25 is separated from the attaching portion 8, that is, when the tool 25 is displaced to the right in FIG. 22, the cover 18 is separated from the outer race 7, so that the cover 18 is disconnected from the outer race 7.
In the conventional structure shown in FIG. 22, the cover 18 is formed from a metallic sheet by means of plastic working. On the other hand, when the cover is made of synthetic resin and the sensor is embedded in a portion of the cover in the process of injection molding, it is possible to reduce the manufacturing cost of the rolling bearing unit having a rotating speed detector. This structure is conventionally known, in which the sensor is embedded in a portion of the cover made of synthetic resin. For example, European Patent Publication No. EP0557931-A1 discloses the above arrangement. This arrangement shown in FIG. 23, which is defined as the fourth conventional example, is described as follows. A sensor 20a is embedded in the cover 18a made of synthetic resin which closes an inside end opening of the outer race 8. Onto an outer circumferential surface of the opening end portion of the cover 18a, a sleeve 31 is fixed, which is formed from a metallic sheet such as a steel sheet having a sufficiently high rigidity, and the section of the sleeve 31 is an L-shape and the entire shape of the sleeve 31 is formed into an annular shape.
When the sleeve 31 is set in a cavity of the mold in the process of injection molding of the cover 18a, it can be embedded in the above synthetic resin. The above cover 18a is fixed to the outer race 8 when the above sleeve 31 is inwardly engaged with an inside end opening of the outer race 8. Compared with the arrangement shown in FIGS. 19 and 20 into which the cover formed from a metallic sheet is incorporated, this arrangement into which the above cover 18a made of synthetic resin is incorporated is advantageous in that the number of components can be reduced so that the combining work can be simplified and the manufacturing cost of the bearing unit can be lowered, and further the cover made of synthetic resin can be made lighter than the cover made of metal.
However, even in the rolling bearing unit having a rotating speed detector shown in FIG. 23, the following problems to be solved may be encountered. When an automobile is running in a rainy day, muddy water is splashed on the cover 18a and the outer race 8, and further in the case of washing an automobile, water is sprayed on the cover 18a and the outer race 8 with high pressure by a washing machine. In this case, both muddy water and washing water are referred to as muddy water hereinafter. When the muddy water enters the cover 18a and the outer race 8, not only the durability of the bearing unit is deteriorated but also the reliability of the rotating speed detector is affected.
For example, in the conventional arrangement shown in FIG. 23, muddy water enters the cover 18a and the outer race 8 through the following two passages denoted by (1) and (2).
(1) A first minute clearance formed between an outer circumferential surface of the sleeve 31 and an inner circumferential surface of the inside end portion of the outer race 8.
(2) A second minute clearance formed between an inner circumferential surface of the sleeve 31 and an outer circumferential surface of the cover 18a made of synthetic resin.
The first minute clearance is made by minute irregularities which inevitably exist on the outer circumferential surface of the sleeve 31. That is, it is inevitable that minute irregularities of several tens .mu.m exist on the surface of the sleeve 31 formed from a metallic sheet such as a stainless steel sheet. For this reason, even when the sleeve 31 is press-fitted into the inside end opening of the outer race 8, the above first minute clearance is made, and there is a possibility that muddy water enters the bearing unit through the first minute clearance.
The above second minute clearance is made by a difference between the thermal expansion coefficient of a metal composing the sleeve 31 and the thermal expansion coefficient of synthetic resin composing the cover 18a . There is a possibility that muddy water enters the bearing unit through the second minute clearance described above.
In the case of the arrangement of the fourth conventional example shown in FIG. 23, it is difficult to assemble a bearing unit without using an exclusive press. Therefore, in a garage having no exclusive press, it is impossible to replace the sensor 20a attached to the cover 18a. As a result, when the rolling bearing unit having a rotating speed detector is inspected and repaired, the cost is raised. When the cover 18a is pulled out from the outer race 8, due to a high frictional force acting between the outer circumferential surface of the end portion of the outer race 8, an end edge (a left end edge in FIG. 23) of the sleeve 31 strongly pushes an outer circumferential portion 52 close to the fore end portion of the synthetic resin composing the cover 18a. As a result, a base of the portion 52 made of synthetic resin is given a shearing force, and there is a high possibility that the portion 52 is damaged. When the portion 52 is damaged, the cover 18a and the sensor 20a embedded in the cover 18a can not be used again, which raises the cost of inspection and maintenance.
In order to prevent the shearing force from being given to the outer circumferential portion 52 close to the fore and portion when the cover 18a is pulled out from the outer race 8, it can be considered to increase an outer diameter of the flange portion 53 formed in the base portion (the right end portion of FIG. 23) of the sleeve 31. When the outer diameter of the flange portion 53 is increased and an outer circumferential portion of the flange portion 53 is protruded from the outer circumferential surface of the cover 18a so that a tool can be hooked at this protruding portion, it is possible to prevent the occurrence of a shearing force which may cause a damage of the portion 52. However, when the outer diameter of the flange portion 53 is simply increased, muddy water sprayed onto the outer side of the flange portion 53 in a rainy day or in the process of washing an automobile tends to enter the inside of the outer race 8 through a contact surface of the sleeve 31 with the outer race 8. Therefore, it is not appropriate to adopt the above countermeasure.
In the rolling bearing unit having a rotating speed detector shown in FIG. 23 into which the cover 18a made of synthetic resin is incorporated, it is possible to reduce the initial cost. On the other hand, it is difficult to remove the cover 18a from the outer race 8 in the arrangement of maintenance and replacement of parts. When the cover 18a is forcibly removed from the outer race 8 in the arrangement shown in FIG. 23, there is a possibility that the end portion 51 of the cover 18a is damaged due to a frictional force that acts between the outer circumferential surface of the sleeve 31 and the inner circumferential surface of the outer ring 8. When a portion of the sleeve 31 and a portion of the cover 18a are outwardly protruded from the outer circumferential surface of the end portion of the outer race 8 in the diametric direction, it is possible to remove the cover 18a from the outer race 8 without damaging the cover 18a. However, when the above means is adopted for removing the cover 18a, the outer diameter of the cover 18a is increased, so that the cover 18a tends to interfere with other parts. Accordingly, the degree of freedom is deteriorated in the design of an automobile.

Rolling bearing unit having an improved structure for preventing foreign material from entering the unit


An oxide semiconductor material having p-type conductivity and a semiconductor device using the oxide semiconductor material are provided. The oxide semiconductor material having p-type conductivity can be provided using a molybdenum oxide material containing molybdenum oxide (MoOy (2<y<3)) having an intermediate composition between molybdenum dioxide and molybdenum trioxide. For example, a semiconductor device is formed using a molybdenum oxide material containing molybdenum trioxide (MoO3) as its main component and MoOy (2<y<3) at 4% or more.

1. Field of the Invention
The present invention relates to an object, a method, a method for producing an object, a process, a machine, manufacture, or a composition of matter. In particular, the present invention relates to, for example, a semiconductor device, a display device, a light-emitting device, a driving method thereof, or a manufacturing method thereof. More particularly, the present invention relates to, for example, a semiconductor material and a semiconductor device using the semiconductor material.
In this specification, a "semiconductor device" generally refers to a device which can function by utilizing semiconductor characteristics; a transistor, a diode, a photoelectric conversion device, an electro-optical device, a light-emitting display device, a memory device, an imaging device, a semiconductor circuit, and an electronic device are all included in the category of the semiconductor device.
2. Description of the Related Art
Attention has been focused on a technique for forming a photoelectric conversion device and a transistor using semiconductor thin films. The transistor is applied to a wide range of semiconductor electronic devices such as an integrated circuit (IC) and an image display device (also simply referred to as a display device). A silicon-based semiconductor material is widely known as a material for a semiconductor thin film applicable to a photoelectric conversion device and a transistor. As another material, an oxide semiconductor has attracted attention.
For example, a technique in which a transistor is manufactured using a Zn—O-based oxide or an In—Ga—Zn—O-based oxide as an oxide semiconductor is disclosed (see Patent Documents 1 and 2).
It is known that many oxide semiconductors have n-type conductivity. Examples of oxide semiconductors having n-type conductivity include materials such as ZnO, In2O3, SnO2, GaO, TeO, GeO2, WO3, and MoO3.
On the other hand, as oxide semiconductors having p-type conductivity, materials such as ZnO, CuAlO2, NiO, and IrO are known.
Further, a photoelectric conversion device that generates power without carbon dioxide emissions and that does not generate any harmful emissions has attracted attention as a countermeasure against global warming. As a typical example of the photoelectric conversion device, a silicon (Si) solar cell which uses single crystal silicon, polycrystalline silicon, or the like has been known, and has been actively researched and developed.
In a solar cell using a silicon substrate, a structure having a p-n homojunction is widely used. Such a structure is formed by diffusion of impurities having a conductivity type opposite to that of the silicon substrate into one surface of the silicon substrate.
On the other hand, in order to improve output voltage in power generation, a structure of a solar cell having a p-n heterojunction in which a wide-gap semiconductor material provided as a window layer and a silicon substrate of a photoelectric conversion layer are combined is known (see Non-Patent Document 1). The p-n heterojunction is formed by formation of a wide-gap semiconductor having a different band gap and conductivity type from those of the silicon substrate on one surface of the silicon substrate.
Further, a structure of a silicon solar cell having a semiconductor-insulator-semiconductor (SIS) structure in which a p-n heterojunction is formed with a thin insulating film provided therebetween is known (see Non-Patent Document 2).

P-type semiconductor material and semiconductor device

Semiconductor Energy Laboratory Co., Ltd.


A purse including a series of flexible plastic inserts that gives the purse shape when the plastic inserts are bent and placed into the soft "skin" of the purse. These plastic inserts can be removed, if desired, so that the "soft" purse can return to a foldable, storable, cleanable state. Purse straps may be detached and interchanged. Purse flaps may be detached and interchanged. A fitted, removable, liner/organizer lets the user change purses without removing the contents piecemeal.

This invention relates to handbags or purses. The term "handbag" is used herein in the broad sense of a container of a size to be carried easily in the hand, on the shoulder, or on the back of a user.
Handbags are frequently made from heavy-weight fabrics, such as heavy cloth, leathers, vinyls, and the like. To retain their shape, they are provided with frames or are layered with stiffeners. Non-shaped purses are made with heavy non-stabilized fabrics that tend to misshape when personal items are placed inside. Because both shaped and non-shaped purses require fabrics which are heavier and stronger than normal garment fabrics in order to avoid stretching or tearing under the strain of frames and items in the purse, purses and clothing that match or coordinate are not normally marketed.
Attempts have been made to permit parts of shaped purses to be interchanged in order to allow some measure of fashion coordination. In some, such as Speakes, U.S. Pat. No. 3,556,187, decorative panels are inserted under a clear plastic cover. In others, such as Gilbert, U.S. Pat. No. 3,234,985, Houis, U.S. Pat. No. 2,694,427, Campos, U.S. Pat. No. 2,435,870, or Reitzel, U.S. Pat. No. 3,692,078, a fabric cover is releasably held to a rigid frame or body. These approaches lack flexibility, have not been aesthetically satisfactory, and have been difficult to use and change.
Currently available handbags also do not give the wearer the ability of "fine tuning" his or her ensemble. The feminine pronoun is used hereafter for simplicity, but it will be understood that the invention may also be used by men.
Conventional shaped handbags cannot be stored flat or packed flat for travel and cannot be easily cleaned.


Golf game management integrates pre-game, in-game, and post-game activities for a golf game into a unified experience. A golf cart-mounted entertainment console includes video cameras, sensory devices worn by the players during the game, and locally-mounted data processing components for modeling collected data. A cart-mounted interface, website, and mobile device application present game-related content that allows players to view and manipulate data before, during and after the game. Multiple data processing modules provide several functions built on data collected from playing a game of golf for players to enjoy an enhanced golf experience.

There are several existing systems and methods of augmenting and enhancing a game of golf. Many of these systems and methods relate to improving shot-making during a game, and utilize global positioning devices to determine player and shot location while a game of golf is in progress on a golf course.
Many of these systems and methods rely on either hand-held measurement devices or products attached to golf clubs to provide information required for meaningful assistance to a golfer in playing a game. Each of these, however, carries with it significant drawbacks.
For example, the use of hand-held devices requires a golfer to spend extra time handling the device, which takes away from the user's experience in actually playing the game. Hand-held devices must also be carried by the golfer, usually either in a golf bag or in one's pocket, resulting in having to think about where the device is instead of enjoying the game in-progress. The golfer may forget to use it, resulting in inconsistent data collection and a degradation of the quality of functionality provided. Finally, such devices may get lost during a game. Meanwhile, devices attached to golf clubs introduce a bulky component to the clubs, which are increasingly engineered to be light-weight, high-performance playing equipment. They may also be easily damaged or broken during club use.
U.S. Patent Application No. 2009/0305822 teaches a prior art system and method for enhancing a golf game in which a global positioning system is used to establish a score database for players. Scoring information is obtained from global positioning devices and stored locally before being updated to a remote computer at a later time. However, there is no method of real-time score updating to provide golfers with in-progress information about their game, or a real-time summary of how others in a golfer's party are faring on the course. There is also no enhanced functionality for making the game more interesting by being able to view video taken or getting shot assistance information while the game is in progress.

Golf game management and entertainment system integrating pre-game, in-game, and post-game content for enhanced golfing experience


A starter motor energized through a relay is protected from low voltages by a circuit which senses low voltages and turns off the motor relay via a transistor switch. A generator voltage sensing circuit also turns off the relay via the same switch when a generator voltage threshold is reached. For operation over a wide system voltage range, the coil of the relay is protected against high voltages by a chopper circuit which operates the transistor switch at a duty cycle of 100% at low voltages across the coil and lower duty cycles at high voltages. For a 12 volt relay the average current at higher voltages is maintained at a value approximating that obtained at a steady state 12 volts.

In heavy vehicles such as military tanks which are subject to extreme environmental conditions the engines can be difficult to start, thus causing the battery voltage to drop at least momentarily to very low levels during starting. Since sustained low voltage operation of the starter motor can be injurious to the motor, it is the practice to provide a protection circuit for the starter motor which monitors the system voltage when the starter is first energized and disables the motor if the voltage remains below a threshold for a prescribed time period.
The protection circuit includes a relay having switching contacts in series with the starter motor. The relay coil is subject to the highly variable system voltage and must be operable throughout the voltage range. However, a coil which is selected for low voltage operation is vulnerable to being burned out if a sustained high voltage is applied. Thus it is desirable to provide some form of protection to avoid the effects of high voltage on the relay coil.
As discussed in the U.S. Pat. No. 4,585,986 to Dyer, entitled "DC Switching Regulated Power Supply For Driving an Inductive Load", it is known to use a switching control method in the art of automatic regulation of DC power to a load. The average power supplied to a load is regulated by a series switch which is operated to chop the current flowing to the load. Control is effected by varying the relative on time or duty cycle which is determined by comparing the load voltage to a reference voltage. In the present invention, it is recognized that regulation akin to that mentioned by Dyer could be applied to the high voltage protection of a relay coil in a starter protection circuit.

Starter motor protection circuit with relay protection