Each pixel of a display device has a current supply circuit, a switch portion, and a light emitting element. The light emitting element, the current supply circuit, and the switch portion are connected in series between a power supply reference line and a power supply line. The switch portion is switched between ON and OFF using a digital video signal. The amount of constant current flowing in the current supply circuit is determined by a control signal inputted from the outside of the pixel. When the switch portion is ON, a constant current determined by the current supply circuit flows in the light emitting element and light is emitted. As a result, a low-cost display device can be provided in which the light emitting element can emit light at a constant luminance even when the current characteristic is changed by degradation or the like, which is fast in writing signals in pixels, which can display in gray scales accurately, and which can be reduced in size with a low cost, as well as a driving method of the display device.

An active matrix display device has been proposed in which each pixel has a light emitting element and a transistor for controlling light emission of the light emitting element. A light emitting element refers to an element which has a first electrode and a second electrode and whose luminance is controlled by the amount of current flowing between the first electrode and the second electrode. Display devices using OLED (Organic Light Emitting Diode) elements as light emitting elements (hereinafter referred to as OLED display devices) are attracting attention. OLED display devices have advantages such as excellent responsiveness, low voltage operation, and wide viewing angle, thereby receiving attention as the next-generation flat panel displays.
In active matrix OLED display devices, luminance information is written in each pixel by a voltage signal or by a current signal. The former is called a voltage writing type and the latter is called a current writing type analog method. These driving methods will be described below using examples.
FIG. 30 shows a structural example of a pixel in a conventional voltage writing type OLED display device. In FIG. 30, each pixel has two TFTs (a first TFT and a second TFT), a capacitor element, and an OLED. The first TFT (hereinafter referred to as selecting TFT), which is denoted by 3001, has a gate electrode connected to a gate signal line 3002 and has a source terminal and a drain terminal one of which is connected to a source signal line 3003. The other of the source terminal and drain terminal of the selecting TFT 3001 is connected to a gate electrode of the second TFT (hereinafter referred to as driving TFT), which is denoted by 3004, and to one of electrodes of the capacitor element (hereinafter referred to as storage capacitor), which is denoted by 3007. The other electrode of the storage capacitor 3007 is connected to a power supply line 3005. The driving TFT 3004 has a source terminal and a drain terminal one of which is connected to the power supply line 3005 and the other of which is connected to a first electrode 3006a of the OLED, which is denoted by 3006. A second electrode 3006b of the OLED 3006 receives a constant electric potential. Here, the electrode of the OLED 3006 that is connected to the driving TFT 3004, namely, the first electrode 3006a, is called a pixel electrode whereas the second electrode 3006b is called an opposite electrode.
The description given below is about a driving method for when the selecting TFT 3001 in FIG. 30 is an n-channel TFT, the driving TFT 3004 is a p-channel TFT, the first electrode 3006a and second electrode 3006b of the OLED are an anode and a cathode, respectively, and the electric potential of the second electrode 3006b is set to 0 V.
A signal is inputted to the gate signal line 3002 to turn the selecting TFT 3001 conductive, and then a signal voltage is inputted to the selecting TFT 3001 from the source signal line 3003. Upon input of the signal voltage from the source signal line 3003, electric charges are accumulated in the storage capacitor 3007. In an amount according to the voltage held in the storage capacitor 3007, a current flows into the OLED 3006 through the source-drain of the driving TFT 3004 from the power supply line 3005 and the OLED 3006 emits light.
Voltage writing type display devices having pixels structured as shown in FIG. 30 can employ two types of driving methods, analog method and digital method. Hereinafter, the two are called as a voltage writing type analog method and a voltage writing type digital method.
In the voltage writing type analog driving method, the gate voltage (gate-source voltage) of the driving TFT 3004 in each pixel is changed to change the drain current of the driving TFT 3004. The method thus changes the amount of current flowing in the OLED 3006 to change the luminance. In order to obtain intermediate gray scale, the driving TFT 3004 operates in a range where a change in drain current is large to a change in gate voltage.
The voltage writing type analog method described above has a problem in that the current flowing in the OLED 3006 fluctuates greatly due to changes in drain current caused by fluctuation in current characteristic of the driving TFT 3004 when signals inputted to pixels from their respective source signal lines 3003 have the same electric potential. Fluctuation in current characteristic of the driving TFT 3004 is influenced by parameters such as threshold voltage and carrier mobility. As an example thereof, fluctuation in current characteristic due to fluctuation in threshold voltage of the driving TFT 3004 is described with reference to FIG. 31.
FIG. 31(A) is a diagram showing only the driving TFT 3004 and OLED 3006 of FIG. 30. The source terminal of the driving TFT 3004 is connected to the power supply line 3005. The gate voltage of the driving TFT 3004 is indicated by Vgs in the drawing. The drain current of the driving TFT 3004 is indicated by an arrow Id in the drawing. FIG. 31(B) shows the relation between the absolute value |Vgs| of the gate voltage of the driving TFT 3004 and its drain current Id (the current characteristic). Denoted by 3101a is a curve showing the relation between the gate voltage and the drain current when the absolute value of the threshold voltage of the driving TFT 3004 is Vth1. On the other hand, 3101b is a curve showing the relation between the gate voltage and the drain current when the absolute value of the threshold voltage of the driving TFT is Vth2. Here, Vth1 is larger than Vth2 (Vth1>Vth2). An operation range (1) shown in the drawing corresponds to the operation range of the driving TFT 3004 in the voltage writing type analog method. If the threshold of the driving TFT 3004 fluctuates in the operation range (1), the drain current of one is Id1 whereas the drain current of another is Id2 and the difference is large even though they have the same gate voltage Vgs1. Fluctuation in threshold voltage causes fluctuation in luminance of the OLED 3006 since the luminance of the OLED 3006 is in proportion to the amount of current flowing in the OLED 3006.
The voltage writing type digital driving method has been proposed in order to reduce the above-described influence of fluctuation in current characteristic of the driving TFT 3004. In the voltage writing type digital driving method, the OLED 3006 of each pixel is in a state chosen from light emission at a constant luminance and no-light emission. The driving TFT 3004 in FIG. 30 serves as a switch to select connection between the power supply line 3005 of each pixel and the pixel electrode 3006a of the OLED 3006. While the OLED 3006 is emitting light in the voltage writing type digital method, the driving TFT 3004 operates in a linear range that is an operation range where the absolute value of a source-drain voltage Vds is smaller than the absolute value of Vgs−Vth obtained by subtracting the threshold Vth from the gate voltage Vgs, particularly, in a range where the absolute value of the gate voltage is large.
The operation range of the driving TFT 3004 in the voltage writing type digital method is an operation range (2) in FIG. 31(B). The operation range (2) is a linear range and, in the driving TFT 3004 operating in this range, fluctuation in drain current due to fluctuation in threshold voltage and the like is small and an almost constant current Id3 flows if the same gate voltage Vgs2 is applied. Therefore fluctuation in current flowing in the OLED 3006 is lowered and changes in light emission luminance are reduced.
The relation between the driving TFT 3004 operating in the linear range, the OLED 3006, and voltages applied to 3004 and 3006 is explained with reference to FIG. 32. FIG. 32(A) shows only the driving TFT 3004 and OLED 3006 of FIG. 30 for the explanation. Here, the source terminal of the driving TFT 3004 is connected to the power supply line 3005. The source-drain voltage of the driving TFT 3004 is indicated by Vds. The voltage between the cathode and anode of the OLED 3006 is indicated by VOLED. The current flowing in the OLED 3006 is denoted by IOLED. The current IOLED equals the drain current Id of the driving TFT 3004. The electric potential of the power supply line 3005 is indicated by Vdd. The electric potential of the opposite electrode of the OLED 3006 is set to 0 V. In FIG. 32(B), 3202a is a curve showing the relation between VOLED and IOLED of the OLED 3006 (I–V characteristic). Denoted by 3201 is a curve showing the relation between the source-drain voltage Vds of the driving TFT 3004 and its drain current Id (IOLED) when the gate voltage is Vgs2 in FIG. 31(B). The operation condition (operation point) of the driving TFT 3004 and OLED 3006 is determined by the intersection point of the two curves. The operation point is an intersection point 3203a of the curve 3201 and the curve 3202a in the linear range shown in the drawing since the driving TFT 3004 operates in the linear range. This means that the voltage between the anode and cathode of the OLED 3006 is VA1 and the current thereof is IOLED1.
On the other hand, in display devices having current writing type analog method pixels, a signal current is inputted to each pixel from a signal line (source signal line). Here, a signal current is current signals linearly corresponding to luminance information of video signals. The gate voltage of a TFT whose drain current is the inputted signal current is held in a capacitor portion. In this way, the OLED keeps receiving the current held by the capacitor portion after the source signal line stops inputting a signal current to the pixel. By changing a signal current inputted to a source signal line as this, the amount of current flowing in an OLED is changed to control the light emission luminance of the OLED and display in gray scales.
As an example of the current writing type analog method pixel, FIG. 33 shows a pixel structure disclosed in "IDW '00 p235: Active Matrix PolyLED Displays", and a driving method thereof will be described. In FIG. 33, a pixel is composed of an OLED 3306, a selecting TFT 3301, a driving TFT 3303, a capacitor element (storage capacitor) 3305, a holding TFT 3302, a light emission TFT 3304, a source signal line 3307, a first gate signal line 3308, a second gate signal line 3309, a third gate signal line 3310, and a power supply line 3311.
A gate electrode of the selecting TFT 3301 is connected to the first gate signal line 3308. The selecting TFT 3301 has a source terminal and a drain terminal one of which is connected to the source signal line 3307 and the other of which is connected to a source terminal or drain terminal of the driving TFT 3303, to a source terminal or drain terminal of the holding TFT 3302, and to a source terminal or drain terminal of the light emission TFT 3304. Of the source terminal and drain terminal of the holding TFT 3302, one that is not connected to the selecting TFT 3301 is connected to one of electrodes of the storage capacitor 3305 and to a gate electrode of the driving TFT 3303. The side of the storage capacitor 3005 that is not connected to the holding TFT 3002 is connected to the power supply line 3311. A gate electrode of the holding TFT 3302 is connected to the second gate signal line 3309. Of the source terminal and drain terminal of the driving TFT 3303, one that is not connected to the selecting TFT 3301 is connected to the power supply line 3311. Of the source terminal and drain terminal of the light emission TFT 3304, one that is not connected to the selecting TFT 3301 is connected to one electrode 3306a of the OLED 3306. A gate electrode of the light emission TFT 3304 is connected to the third gate signal line 3310. The other electrode 3306b of the OLED 3306 is kept at a constant electric potential. Of the two electrodes 3306a and 3306b of the OLED 3306, one that is connected to the light emission TFT 3304, i.e., the electrode 3306a is called a pixel electrode and the other electrode, i.e., the electrode 3306b is called an opposite electrode.
In the pixel structured as shown in FIG. 33, the current value of a signal current inputted to the source signal line is controlled by a video signal input current supply 3312. In practice, plural video signal input current supplies 3312 respectively associated with plural pixel columns correspond to a part of a source signal line driving circuit. In the example shown here, the pixel has n-channel TFTs for the selecting TFT 3301, the holding TFT 3302, and the light emission TFT 3304, and has a p-channel TFT for the driving TFT 3303, and the pixel electrode 3306a serves as an anode.
A driving method of the pixel having the structure of FIG. 33 is described with reference to FIGS. 34 and 35. In FIG. 34, the selecting TFT 3301, the holding TFT 3302, and the light emission TFT 3304 are shown as switches to make it easy to see whether they are in a conductive state or nonconductive state. Pixel states (A1) to (A4) correspond to states in periods TA1 to TA4 in a timing chart of FIG. 35, respectively.
In FIG. 35, G_1, G_2, and G_3 represent electric potentials of the first gate signal line 3308, second gate signal line 3309, and third gate signal line 3310, respectively. |Vgs| is the absolute value of the gate voltage (gate-source voltage) of the driving TFT 3303. IOLED is the current flowing in the OLED 3306. IVideo is the current value determined by the video signal input current supply 3312.
In the period TA1, a signal inputted to the first gate signal line 3308 turns the selecting TFT 3301 conductive and a signal inputted to the second gate signal line 3309 turns the holding TFT 3302 conductive. Then the power supply line 3311 is connected to the source signal line 3307 through the driving TFT 3303 and the selecting TFT 3301. The current amount IVideo determined by the video signal input current supply 3312 flows in the source signal line 3307 and, therefore, when enough time has elapsed to reach the steady state, the drain current of the driving TFT 3303 becomes IVideo and a gate voltage according to the drain current IVideo is held in the storage capacitor 3005. At this point, the light emission TFT 3304 is in a nonconductive state. After the voltage is held in the storage capacitor 3005 and the drain current of the driving TFT 3303 is fixed to IVideo, the signal of the second gate signal line 3309 is changed in the period TA2 to turn the holding TFT 3302 nonconductive.
Next, in the period TA3, the signal of the first gate signal line 3308 is changed to turn the selecting TFT 3301 nonconductive. In the period TA4, a signal inputted to the third gate signal line 3310 turns the light emission TFT 3304 conductive and then the signal current IVideo is inputted to the OLED 3306 through the source-drain of the driving TFT 3303 from the power supply line 3311. In this way, the OLED 3306 emits light at a luminance according to the signal current IVideo.
A series of operations in the periods TA1 through TA4 is called a signal current IVideo writing operation. In the operation, the signal current IVideo is changed in an analog fashion to change the luminance of the OLED 3306 and display in gray scales.
In the timing chart of FIG. 35, the absolute value |Vgs| of the gate voltage of the driving TFT 3303 is increased with time in the period TA1 and an operation of holding a gate voltage according to the drain current IVideo is shown. This corresponds to the case where electric charges are not held in the storage capacitor 3305 when the writing operation is started, or the case where the absolute value |Vgs| of the gate voltage of the driving TFT 3303 that is held in the preceding writing operation is smaller than the absolute value |Vgs| of the gate voltage of the driving TFT 3303 of when a given drain current that is determined by the video signal input current supply 3312 flows in the subsequent writing operation.
If the absolute value |Vgs| of the gate voltage of the driving TFT 3303 that is held in the preceding writing operation is larger than the absolute value |Vgs| of the gate voltage of the driving TFT 3303 of when a given drain current that is determined by the video signal input current supply 3312 flows in the subsequent writing operation, the absolute value |Vgs| of the gate voltage of the driving TFT 3303 is reduced with time in the period TA1 and an operation of holding a gate voltage according to the drain current IVideo is observed.
In the current writing type analog method display device described above, the driving TFT 3303 operates in a saturation region. The drain current of the driving TFT 3303 is determined by a signal current inputted from the source signal line 3307. This means that the gate voltage of the driving TFT 3303 is automatically changed so that a constant drain current flows irrespective of fluctuation in threshold voltage, mobility, or the like.
A pixel structure disclosed in JP 2001-147659 A is shown in FIG. 29 as another example of the current writing type analog method pixel, and a driving method thereof will be described in detail. In FIG. 29, a pixel is composed of an OLED 2906, a selecting TFT 2901, a driving TFT 2903, a current TFT 2904, a capacitor element (storage capacitor) 2905, a holding TFT 2902, a source signal line 2907, a first gate signal line 2908, a second gate signal line 2909, and a power supply line 2911.
A gate electrode of the selecting TFT 2901 is connected to the first gate signal line 2908. The selecting TFT 2901 has a source terminal and a drain terminal one of which is connected to the source signal line 2907 and the other of which is connected to a source terminal or drain terminal of the current TFT 2904 and to a source terminal or drain terminal of the holding TFT 2902. Of the source terminal and drain terminal of the current TFT 2904, one that is not connected to the selecting TFT 2901 is connected to the power supply line 2911. Of the source terminal and drain terminal of the holding TFT 2902, one that is not connected to the selecting TFT 2901 is connected to one of electrodes of the storage capacitor 2905 and to a gate electrode of the driving TFT 2903. The other side of the storage capacitor 2905 is connected to the power supply line 2911. A gate electrode of the holding TFT 2902 is connected to the second gate signal line 2909. The driving TFT 2903 has a source terminal and a drain terminal one of which is connected to the power supply line 2911 and the other of which is connected to one electrode 2906a of the OLED 2906. The other electrode 2906b of the OLED 2906 is kept at a constant electric potential. The electrode 2906a of the OLED 2906 that is connected to the driving TFT 2903 is called a pixel electrode and the other electrode, 2906b, is called an opposite electrode.
In the pixel structured as shown in FIG. 29, the current value of a signal current inputted to the source signal line 2907 is controlled by a video signal input current supply 2912. In practice, plural video signal input current supplies 2912 respectively associated with plural pixel columns correspond to a part of a source signal line driving circuit.
In the example shown in FIG. 29, the pixel has n-channel TFTs for the selecting TFT 2901 and the holding TFT 2902 and p-channel TFTs for the driving TFT 2903 and the current TFT 2904, and the pixel electrode 2906a serves as an anode. Here, consider the current characteristic of the driving TFT 2903 as identical with the current characteristic of the current TFT 2904 for simplification. A driving method of the pixel having the structure of FIG. 29 is described with reference to FIGS. 28 and 27. In FIG. 28, the selecting TFT 2901 and the holding TFT 2902 are shown as switches to make it easy to see whether they are in a conductive state or nonconductive state. Pixel states (TA1) to (TA3) correspond to states in periods TA1 to TA3 in a timing chart of FIG. 27, respectively.
In FIG. 27, G_1 and G_2 represent electric potentials of the first gate signal line 2908 and second gate signal line 2909, respectively. |Vgs| is the absolute value of the gate voltage (gate-source voltage) of the driving TFT 2903. IOLED is the current flowing in the OLED 2906. IVideo is the current value determined by the video signal input current supply 2912.
In the period TA1, a signal inputted to the first gate signal line 2908 turns the selecting TFT 2901 conductive and a signal inputted to the second gate signal line 2909 turns the holding TFT 2902 conductive. Then the power supply line 2911 is connected to the source signal line 2907 through the current TFT 2904, the holding TFT 2902, and the selecting TFT 2901. The current amount IVideo determined by the video signal input current supply 2912 flows in the source signal line 2907 and, therefore, when enough time has elapsed to reach the steady state, the drain current of the current TFT 2904 becomes IVideo and a gate voltage corresponding to the drain current IVideo is held in the storage capacitor 2905.
After the voltage is held in the storage capacitor 2905 and the drain current of the current TFT 2904 is fixed to IVideo, the signal of the second gate signal line 2909 is changed in the period TA2 to turn the holding TFT 2902 nonconductive. At this point, the drain current IVideo flows in the driving TFT 2903. In this way, the signal current IVideo is inputted to the OLED 2906 through the driving TFT 2903 from the power supply line 2911. The OLED 2906 emits light at a luminance according to the signal current IVideo.
Next, in the period TA3, the signal of the first gate signal line 2908 is changed to turn the selecting TFT 2901 nonconductive. The signal current IVideo is kept supplied to the OLED 2906 through the driving TFT 2903 from the power supply line 2911 after the selecting TFT 2901 is made nonconductive and the OLED 2906 continues emitting light.
A series of operations in the periods TA1 through TA3 is called a signal current IVideo writing operation. In the operation, the signal current IVideo is changed in an analog fashion to change the luminance of the OLED 2906 and display in gray scales.
In the current writing type analog method display device described above, the driving TFT 2903 operates in a saturation region. The drain current of the driving TFT 2903 is determined by a signal current inputted from the source signal line 2907. This means that the gate voltage of the driving TFT 2903 is automatically changed so that a constant drain current flows irrespective of fluctuation in threshold voltage, mobility, or the like if the driving TFT 2903 and the current TFT 2904 in the same pixel have the same current characteristic.
The relation between the voltage applied to an OLED and the amount of current flowing therein (the I–V characteristic) is changed by environment temperature of the surroundings, degradation of the OLED, and the like. Therefore a problem of conventional display devices in which driving TFTs operate in a linear range, typically, voltage writing type digital method display devices, is that the amount of current actually flows is varied even when a constant voltage is applied between two electrodes of an OLED.
FIG. 36 show a change in operation point when the I–V characteristic of an OLED is changed by degradation or the like in a display device using a conventional voltage writing type digital driving method.
FIG. 36(A) is a diagram showing only the driving TFT 3004 and OLED 3006 of FIG. 30. Here, the source terminal of the driving TFT 3004 is connected to the power supply line 3005. The source-drain voltage of the driving TFT 3004 is indicated by Vds. The voltage between the cathode and anode of the OLED 3006 is indicated by VOLED and the current thereof is denoted by IOLED. The current IOLED equals the drain current Id of the driving TFT 3004. The electric potential of the power supply line 3005 is indicated by Vdd. The electric potential of the opposite electrode of the OLED 3006 is set to 0 V.
In FIG. 36(B), a curve 3202a shows the I–V characteristic of the OLED 3006 before degradation and a curve 3202b shows its I–V characteristic after degradation. The operation condition of the driving TFT 3004 and OLED 3006 before degradation is determined by an intersection point 3203a between the curve 3202a and a curve 3201. The operation condition of the driving TFT 3004 and OLED 3006 after degradation is determined by an intersection point 3203b between the curve 3202b and the curve 3201.
In a pixel for which a light emission state is chosen, a gate electric potential that turns the driving TFT 3004 conductive is inputted to 3004. At this point, the voltage between the two electrodes of the OLED 3006 is VA1. When the OLED 3006 is degraded to change its I–V characteristic, the operation point is changed even though the same gate voltage is inputted, and the current flowing therein is changed from IOLED1 to IOLED2 even though almost the same voltage VA1 is applied between the two electrodes of the OLED 3006. The light emission luminance of the OLED 3006 is thus changed according to the degree of degradation of the OLED 3006 in each pixel.
On the other hand, in display devices which have the pixel structure shown in FIG. 33 or FIG. 29 and which use the conventional current writing type analog driving method, the luminance is expressed by a constant current flowing into an OLED. Degradation or the like causes a change in I–V characteristic of the OLED in this case and influence of the change is described with reference to FIG. 37. Components common to FIG. 37 and FIG. 33 are denoted by the same symbols and explanations thereof are omitted. In FIG. 33, the light emission TFT 3304 is simply deemed as a switch and the source-drain voltage thereof is ignored.
FIG. 37(A) shows only the driving TFT 3303 and OLED 3306 of FIG. 33. Here, the source terminal of the driving TFT 3303 is connected to the power supply line 3305. The source-drain voltage of the driving TFT 3303 is indicated by Vds. The voltage between the cathode and anode of the OLED 3306 is indicated by VOLED. The current flowing in the OLED 3306 is denoted by IOLED. The current IOLED equals the drain current Id of the driving TFT 3303. The electric potential of the power supply line 3305 is indicated by Vdd. The electric potential of the opposite electrode of the OLED 3306 is set to 0 V.
In FIG. 37(B), 3701 is a curve showing the relation between the source-drain voltage of the driving TFT 3303 and its drain current. Denoted by 3702a is a curve showing the I–V characteristic of the OLED 3306 before degradation and 3702b is a curve showing the I–V characteristic of the OLED 3306 after degradation. The operation condition of the driving TFT 3303 and OLED 3306 before degradation is determined by an intersection point 3203a between the curve 3702a and a curve 3701. The operation condition of the driving TFT 3303 and OLED 3306 after degradation is determined by an intersection point 3703b between the curve 3702b and the curve 3701.
In the current writing type analog method pixel, the driving TFT 3303 operates in a saturation region. Through degradation of the OLED 3306, the voltage between the two electrodes of the OLED 3306 changes from VB1 to VB2, but the current flowing in the OLED 3306 is kept almost constant at IOLED1. This change in operation condition of the driving TFT and OLED due to a change in I–V characteristic of the OLED applies to the driving TFT 2903 and the OLED 2906 in the pixel structure shown in FIG. 29.
However, the current writing type analog driving method needs to hold electric charges according to a signal current anew in a capacitor portion (storage capacitor) of each pixel each time pixels are used for display. Holding a given level of electric charges in a storage capacitor, when signals are written in a pixel, takes longer as the signal current becomes smaller because of cross capacitance of wirings or the like. Therefore it is difficult to write a signal current quickly.
A small signal current also increases influence of noises such as leak current caused by plural pixels that are connected to the same source signal line other than the pixel in which a signal current is being written. Accordingly there is a strong possibility that the pixel cannot emit light at an accurate luminance.
In a pixel structure having a current mirror circuit, which is represented by a pixel as the one shown in FIG. 29, a pair of TFTs whose gate electrodes are connected have to have the same current characteristic in the current mirror circuit. However, in practice, matching the current characteristics of the TFTs that forms a pair exactly is difficult and it results in fluctuation.
Here, the driving TFT 2903 and current TFT 2904 of FIG. 29 are given a threshold Vtha and a threshold Vthb, respectively. Now let us examine displaying black when their threshold fluctuates and the absolute value |Vtha| of Vtha is smaller than the absolute value |Vthb| of Vthb. The drain current flowing in the current TFT 2903 corresponds to the current value IVideo determined by the video signal input current supply 2912 and is zero. However, there is a possibility that a voltage slightly smaller than |Vthb| is held in the storage capacitor 2905 although no drain current flows in the current TFT 2903. Then the drain current of the driving TFT 2903 might not be zero since |Vthb|>|Vtha|. In this way, a drain current flows in the driving TFT 2903 to cause the OLED 2906 to emit light even though black display is intended. This brings a problem of reduction in contrast.
Furthermore, conventional current writing type analog method display devices have a video signal input current supply for inputting a signal current in each pixel for each column of pixels, and the devices have to make current characteristics of all the video signal input current supplies match and control the current value so as to change the current value accurately in an analog fashion. For that reason, it is difficult to manufacture video signal input current supplies having the same current characteristic in transistors that use a polycrystalline semiconductor thin film. The video signal input current supplies are therefore manufactured from an IC chip. On the other hand, pixels are generally formed on a glass or other insulating substrate (a substrate having an insulating surface) from cost and other reasons. Then the IC chip has to be bonded to the glass or other insulating substrate. Bonding the chip requires a large area, which is a problem because it makes reduction of the frame area in the periphery of the pixel region impossible.
The present invention is proposed in view of the above, and has an object of providing a low-cost display device with a reduced size in which a light emitting element can emit light at a constant luminance irrespective of a change in current characteristic due to degradation or the like, which is fast in writing signals in pixels, and which is capable of displaying in precise gray scales, as well as a method of driving the display device.

Display device and driving method thereof

Semiconductor Energy Laboratory Co., Ltd.


This invention relates to a method for producing a ruthenium catalyst in which ruthenium supported on at least one metal oxide is pretreated with an aldehyde compound, a phosphorus compound, and a lower alcohol compound, and a method for producing alkyl- or alkenyl-substituted compound using the ruthenium catalyst.

A method for producing an alkyl- or alkenyl-substituted compound, an industrially important key compound, by an addition reaction to an unsaturated compound that involves carbon-carbon bond formation due to regioselective activation of a carbon-hydrogen bond is an excellent method with an atom efficiently of 100% that eliminates the need for prior activation of substrates, and that theoretically produces no by-products.
A method for producing such key compounds through the above route using a homogeneous complex catalyst containing metal such as ruthenium, palladium, or cobalt, is known (for example, Non-patent Literature 2 to 13). However, there are practical problems with the use of homogeneous complex catalysts, such as: 1) the catalyst production process is complicated, resulting in high environmental burden and high costs; 2) it is difficult to separate/recover and recycle the catalysts, which poses a problem of contamination of products by metals; and 3) in general, homogeneous complex catalysts are chemically and thermally unstable, and thus difficult to handle.
A production method that uses a solid catalyst is proposed, for example, in Patent Literature 1 and Non-patent Literature 1 to address the above problems. Although problems 1) to 3) described above, which are caused when homogeneous complex catalysts are used, can be solved by the methods of Patent Literature 1 and Non-patent Literature 1, there are problems such that the unsaturated compound that undergoes addition is limited to vinylsilane having at least one alkoxy group, and that the catalyst easily loses activity when recycled. For practical use in addition to such problems, catalytic activity must be further improved.

Method for producing ruthenium catalyst and method for producing alkyl group—or alkenyl group-substituted compound using ruthenium catalyst


The present invention relates to a wireless communication system (C) comprising at least one base station (1) in a communication cell (2), from which base station (1) at least two essentially uncorrelated antenna radiation lobes (7, 8, 9, 10) are formed. Each antenna radiation lobe (7, 8, 9, 10) communicates a MIMO (Multiple Input Multiple Output) communication stream. The system (C) further comprises at least one repeating transmitter/receiver (repeater) (18, 19, 20, 21), which is arranged for communicating one of the MIMO communication streams to and/or from at least one UE (user equipment) (12). The present invention also relates to a repeater that is a part of the system (C), and a method for communicating at least two MIMO communication streams to and/or from at least one UE (user equipment) (12), using at least one repeater (18, 19, 20, 21).

The demand for wireless communication systems has grown steadily, and is still growing, and a number of technological advancement steps have been taken during this growth. In order to acquire increased system capacity and user bit rate for wireless systems by employing uncorrelated propagation paths, MIMO (Multiple Input Multiple Output) systems have been considered to constitute a preferred technology for improving the capacity. MIMO employs a number of separate independent signal paths, for example by means of several transmitting and receiving antennas. Each path communicates a communication stream.
In order for a MIMO system to function efficiently, uncorrelated, or at least essentially uncorrelated, transmitted signals are required. The meaning of the term "uncorrelated signals" in this context is that the radiation patterns are essentially orthogonal. This is made possible for one antenna if that antenna is made for receiving and transmitting in at least two orthogonal polarizations, i.e. polarization diversity. Antennas for MIMO systems may also utilize spatial separation, i.e. physical separation, in order to achieve low correlation between the received signals at the antenna ports. It is also possible to combine spatial separation with polarization diversity, i.e. having at least two antennas separated by 5-10 wavelengths (calculated from the centre frequency of the frequency band for which the antennas are designed), which antennas also are arranged for transmission and reception of signals having orthogonal polarizations.
A base station in a MIMO system may thus be arranged with a number of antennas, separated by 5-10 wavelengths, each one of the base station antennas either being designed for one polarization or two orthogonal polarizations.
However, in an urban environment, where a user equipment (for example a mobile phone or a portable computer) is arranged for communicating with such a base station, a number of objects such as large buildings may block the signal path between the base station and the user equipment, causing a number of reflections. Therefore, the signal to noise ratio (SNR) becomes deteriorated, and thus the signals transmitted between the base station and the user equipment become more and more noisy the more buildings that are in the way.
In WO 2005/064872 a repeater system is described, where a base station having multiple antennas communicates via relay stations. The relay stations relay signals to the user equipment via a number of separate channels, where the channelization for example is in the frequency or time domain. This solution presents a problem, since, if the frequency domain is used, there is a shortage of frequencies to be used due to spectral shortage. If the time domain is used, the system becomes slow.

Wireless communication MIMO system with repeaters


A liquid crystal display device includes a TFT substrate having a first alignment film formed on part of an inorganic insulating film, an overcoat film formed on a black matrix, a counter substrate having a second alignment film formed on the overcoat film, and a seal portion including a sealant. The TFT substrate is bonded to the counter substrate by the sealant. The sealant is bonded to the inorganic insulating film at the seal portion on the side where the TFT substrate is formed, with the first alignment film not being provided on the side, and, in the seal portion on the side where the counter substrate is formed, the sealant is bonded to the second alignment film but, is not bonded to the overcoat film.

1. Field of the Invention
The present invention relates to a display device. The invention particularly relates to an IPS liquid crystal display device in which the reliability of a seal portion is improved.
2. Description of the Related Art
A liquid crystal display device includes a TFT substrate having pixel electrodes, thin film transistors (TFT), or the like formed thereon in a matrix form, and a counter electrode opposing the TFT substrate and having color filters, or the like formed at positions corresponding to the pixel electrodes of the TFT substrate. Liquid crystal is put between the TFT substrate and the counter substrate. The liquid crystal display device controls light transmittance for each pixel by using liquid crystal molecules to form images.
Since the liquid crystal display devices are flat and light in weight, their application has been generalized in various fields including large-sized display devices such as television sets, mobile phones, DSCs (Digital Still Cameras), or the like. In contrast, the liquid crystal display devices involve a problem in terms of viewing angle characteristics. The viewing angle characteristics are a phenomenon that the brightness or chromaticity changes between when a screen is observed from the front and when the screen is observed in the oblique direction. The IPS (In Plane Switching) mode of operating liquid crystal molecules by a horizontal electric field has satisfactory viewing angle characteristics.
In the IPS mode, preferred characteristics are obtained when a pre-tilt angle is not formed with respect to liquid crystal molecules near an alignment film. Accordingly, it is advantageous to form the axis of orientation for the alignment film not by a rubbing method but by an optical alignment method. The optical alignment method also has an advantage over the rubbing method in that static electricity is not generated.
In optical alignment method, a polarized UV light is radiated to an alignment film, and thereby, such anisotropy that liquid crystal molecules are aligned in a predetermined direction, is provided to the alignment film. JP-A-2005-351924 describes a technique relating to such optical alignment.

Panasonic Liquid Crystal Display Co., Ltd.


An electrical or electro-optical device (100) includes a first layer (110) having a first composition. The first composition includes a plurality of electrically connected particles. A second layer (130) has a second composition, the second composition including a plurality of electrically connected particles. A composite layer (120) is disposed between the first and second layer. The composite layer is an interpenetrated network of a third and a fourth composition, wherein the third composition is different from the fourth composition. A first electrically interconnected network extends from the first composition in the first layer (110) to the third composition throughout a thickness of the composite layer (120), and a second electrically interconnected network extends from the second composition in the second layer (130) to the fourth composition throughout the thickness of the composite layer.

The contact area between a first and a second material is known to significantly impact the performance of a variety of electrical and electrical and electro-optical devices. Although easy to fabricate, conventional, substantially planar contacts generally minimize the contact area. For example, in solar cells, the charge separation responsible for generating useful power occurs only for that fraction of the incident light that is absorbed in the region of the built in potential, near the interface between two distinct materials (e.g. an n and p type semiconductor for a homo-junction or distinct semiconductors for hetero-junctions). Increasing that surface area of contact will extend the volume over which the absorbed light generates useful power, hence more efficiently utilizing the incident radiation. In a light emitting diode the light emission typically occurs at the junction between two distinct materials where electrons injected from one side and holes from the other radiatively combine. Here, increasing the surface area of contact can result in more light output from the device.
When electrical contact must be made to a semiconductor for the purpose of charge injection or extraction, contact barriers frequently arise between the semiconductor and the electrical conductor used to make the electrical contact. Simply increasing the surface area of contact can increase the net amount of current injected/extracted. Accordingly, a method for forming high contact area interfaces, including semiconducting junction comprising devices, would be highly desirable.

Method for forming interpenetrating networks of distinct materials and devices therefrom

University of Florida Research Foundation, Inc.


A data processing apparatus and method are providing for arbitrating access to a shared resource. The data processing apparatus has a plurality of logic elements sharing access to the shared resource, and arbitration circuitry which is responsive to requests by one or more of the logic elements for access to the shared resource to perform a priority determination operation to select one of the requests as a winning request. The arbitration circuitry applies an arbitration policy to associate priorities with each logic element, the arbitration policy comprising multiple priority groups, each priority group having a different priority and containing at least one of the logic elements. Within each priority group, the arbitration circuitry applies a priority ordering operation to attribute relative priorities to the logic elements within that priority group. Responsive to a predetermined event, the arbitration circuitry re-applies the priority ordering operation within at least one priority group prior to a subsequent performance of the priority determination operation. Such an approach has been found to provide a particularly flexible mechanism for performing arbitration, allowing a wide variety of different arbitration schemes to be implemented using the same arbitration hardware.

Within a data processing apparatus, it is known to provide one or more resources which are shared amongst a plurality of logic elements of the data processing apparatus. For example, the plurality of logic elements may take the form of a plurality of master logic units, and the shared resource may take the form of a slave logic unit with respect to which the various master logic units can initiate transactions. Each transaction typically consists of an address transfer from a master logic unit to a slave logic unit, and one or more data transfers between the master logic unit and the slave logic unit. For a write transaction, these data transfers will pass from the master logic unit to the slave logic unit (in some implementations there will additionally be a write response transfer from the slave logic unit to the master logic unit), whilst for a read transaction these data transfers will pass from the slave logic unit to the master logic unit.
To enable each transaction to take place, a communication path needs to be established between the master logic unit initiating the transaction, and the slave logic unit to which the transaction is directed. If the slave logic unit is shared amongst a plurality of master logic units, then this can cause contention amongst the various master logic units for access to the shared slave logic unit, and this contention can occur at a variety of points within the data processing apparatus.
For example, dependent on the mechanism provided for establishing the communication paths, it may be possible to provide separate dedicated communication paths for each master logic unit. However, since the slave logic unit will typically only be able to handle one transaction at a time, this leads to contention at the input to the slave logic unit itself, and typically it is then necessary to provide arbitration circuitry to arbitrate between multiple simultaneous access requests issued by different master logic units and seeking to access the same shared slave logic unit.
More typically, the mechanism used to establish the communication paths between master logic units and slave logic units is also shared amongst the various master and slave logic units. Accordingly there will typically be points along the communication paths between a master logic unit and a slave logic unit which involve use of a shared physical connection medium, and accordingly arbitration is typically required at such points along the communication paths.
For example, a data processing apparatus may provide interconnect circuitry for coupling the various master logic units and slave logic units, with the interconnect circuitry providing a plurality of connection paths over which such communication paths can be established. Often, certain of the connection paths are shared between multiple logic units, and accordingly arbitration circuitry is provided to arbitrate access to such connection paths. In such instances, it can be seen that the connection paths themselves form a shared resource.
Hence, it will be appreciated that within a typical data processing apparatus, there will be a variety of shared resources and wherever multiple logic elements are contending for access to that shared resource, arbitration circuitry is typically provided to arbitrate amongst those logic elements so as to decide at any point in time which logic element should have access to that shared resource.
Typically, the arbitration circuitry will be configured to apply a particular arbitration policy to decide which logic element to grant access to the shared resource at any particular point in time. For example, a known arbitration scheme may use an algorithm that employs a fixed priority technique, whereby particular priority levels are associated with particular logic elements, and then when multiple logic elements are seeking to access a shared resource at the same time, the arbitration circuitry grants access to the logic element having the highest priority. An alternative known arbitration policy applies a round robin (fair share) technique, which may for example be appropriate when all of the various logic elements that may access the shared resource are considered to have equal priority, and the aim is to seek to provide each logic element with the same level of access to the shared resource.
Whilst certain known arbitration policies are more suited to certain situations than others, typically the arbitration circuitry within the data processing apparatus will be configured to employ one particular arbitration policy which leads to a lack of flexibility in the design. Accordingly, it would be desirable to provide a more flexible technique for performing arbitration within a data processing apparatus.

Data processing apparatus and method for arbitrating access to a shared resource


A mechanism is provided for handling interrupt actions for inter-thread communication. In association with a first processor thread, a thread action data structure is provided that comprises a non-blocking synchronization data structure and an internal list data structure of pending interrupts having no form of synchronization. A post of an interrupt action is received from a second processor thread to the thread action data structure associated with the first processor thread, where the interrupt action is added to the non-blocking synchronization data structure of the thread action data structure. The interrupt action is moved from the non-blocking synchronization data structure to the internal list data structure of pending interrupts for handling by the first processor thread. The internal list data structure of pending interrupts is processed to thereby handle interrupt actions moved to the internal list data structure.

The present application relates generally to an improved data processing apparatus and method and more specifically to mechanisms for efficiently handling interrupt actions in inter-thread communications.
In systems programming, an interrupt is a signal to a processor or, more specifically, a thread within the processor indicating an event that needs immediate attention. Such interrupts alert a thread to a high-priority condition requiring the interruption of the current code the thread is executing. The thread responds by suspending its current activities, saving its state, and executing a small program called an interrupt handler or interrupt service routine (ISR) to deal with the event. This interruption is temporary, and after the interrupt handler finishes, the thread resumes execution of the previous workload.
However, there are other interrupts utilized within a processor. That is, in multi-threaded processors, the multiple threads within the processor communicate with each other through the use of thread interrupts. While these thread interrupts do not need to be handled immediately, it is important to maintain the integrity of the data structures that are used to implement the thread interrupts so that additional performance issues are not introduced.

This patent is subject to a terminal disclaimer.

Handling interrupt actions for inter-thread communication

International Business Machines Corporation


An implement for keeping dairy animals, provided with a first and a second production unit and with a care unit having a plurality of subunits, wherein each production unit is provided with at least one accommodation area for a production group, which comprises a group of lactating dairy animals, and with a milking implement for milking the production group, wherein the subunits of the care unit at least include a calving unit for separately accommodating dairy animals in a calving period, and a milking implement for milking newly calved dairy animals, and an infirmary unit for separately accommodating sick animals, and wherein the care unit forms a connection between the production units. There is thus provided a compact disposition, comprising efficient and short distances, for dairy animals requiring care.

1. Field of the Invention
The present invention relates to an implement for keeping dairy animals. In particular, the invention relates to such an implement intended for large numbers of dairy animals, in the order of a plurality of hundreds of dairy animals. However, it is not excluded to apply the invention to smaller numbers of dairy animals.
2. Description of the Related Art
Implements for keeping dairy animals, having a plurality of production units, in which lactating dairy animals are kept, are known.
A problem of such implements is that they soon become complex because of their size, it being very time-consuming for the manager to provide the care required.
Thus, there is a particular need for an implement of the mentioned type which does not, or at least to a reduced extent, have the mentioned drawback, and in particular enabling an operation which is little time-consuming.


A method of attaching a cabinet assembly to a spa. The method includes providing a frame that has a channel that forms a perimeter. A spa is placed on the frame such that a flange or lip of the spa extends past the perimeter created by the channel. A plurality of slats are then secured between the flange of the spa and the channel of the frame in order to form a cabinet around the spa. The spa having a pan and a toe kick secured adjacent its bottom end.

This invention relates to an assembly of a spa or hot tub. More specifically, this invention relates to attaching the cabinet assembly around and to a hot tub.
Spas have been used for leisure activities for many years. Specifically, a large tub is presented that holds heated water and typically contains a plurality of jets to whirl water around the tub as desired. Typically, a spa is held up by a frame that is not aesthetically pleasing to a casual observer. As a result, a cabinet assembly is placed around the frame to provide a more aesthetically pleasing look.
This cabinet assembly is made by building a wooden or metal frame and then securing to that frame a plurality of rigid individually manufactured panels utilizing fastening members such as screws. Then, if this cabinet assembly is built separate from the spa, the spa still needs to be either placed within the cabinet assembly or the cabinet assembly placed around the spa.
While this wood frame used in combination with the manufactured rigid panels covers up the spa frame thus providing an aesthetically pleasing look, problems still remain. Specifically, building the wood frame is not only time consuming but additionally the individually manufactured pieces can be very costly. In addition, the wood frame provides minimal insulation for the hot tub or spa itself wherein often the water within the spa is desired to be at an elevated temperature. Thus, inefficiencies of the spa occur.
In addition, problems occur with cabinets used as a part of spas because the environment in which spas are generally used is harsh and causes deterioration over time. This is because conventionally many spas are merely placed on the open ground. This often leads to the lower end of the spa cabinet being continually exposed to a certain amount of moisture which causes accelerated deterioration to the lower portion of a wood cabinet. In addition, what complicates the matter is that water, moisture, chemicals and heat are an intrinsic and unavoidable part of spas. These conditions can accelerate and further contribute to the deterioration of a spa's cabinet.
Therefore, a principal object of the invention is to provide a method of attaching a cabinet assembly to a spa that is both efficient and cost effective.
Another object of the invention is to provide a cabinet assembly that resists deterioration over time.
Yet another object of the invention is to provide a system wherein a single frame can be used with several configurations while being simplistic in design.
Yet another object of the invention is to provide a spa system wherein the panels are quickly and easily reversible.
These and other objects, features or advantages will become apparent from the specification and claims.

Method of attaching a cabinet assembly to a hot tub


Compounds of formula (I)

Nuclear hormone receptors make up a family of ligand-inducible transcription factors whose members are involved in multiple physiological and developmental functions. During the last 20 years, more than sixty structurally and functionally related proteins belonging to this family have been identified. Nuclear hormone receptor family includes, in addition to classical steroid receptors (estrogen receptor, progesterone receptor, androgen receptor, glucocorticoid receptor and mineralo-corticoid receptor) also receptors e.g. for thyroid hormone, vitamin D and retinoids. Furthermore, a subclass of so-called orphan receptors for which no ligands have been identified up to date belong to this protein family. See Mangelsdorf et al, Cell (1995) 83(6): 835-839 and references therein. There exists an intense research directed to identify novel modulators for these proteins, ultimate goal thus being to find new therapies and treatment options for conditions and diseases modulated by nuclear/steroid receptors.
Steroidal androgens have been used for decades in the treatment of diseases resulting from deficiency in androgen action. They have also received attention for their use as hormone replacement therapy of aging men and in regulation of male fertility. However, current steroidal androgens, such as synthesized testosterone and its derivatives, have severe limitations. Testosterone is rapidly degraded by the liver and thus has a low systemic bioavailability after oral administration. Further, orally available testosterone formulations, e.g. methyltestosterone, have been associated with alterations in liver function. Various other attempts have been made to overcome these drawbacks of steroidal androgens as therapeutic agents, but with limited success. Current testosterone formulations used in clinical practice include e.g. injections, patches and gels.
In recent years, there has been growing interest in the development of nonsteroidal modulators for steroid receptors for therapeutical use. It has been shown that nonsteroidal ligands can achieve better receptor selectivity and better physicochemical, pharmacokinetic and pharmacological properties. For androgen receptor (AR), nonsteroidal antagonists (antiandrogens) are now used clinically to counteract the undesirable actions of excessive androgens. In contrast, nonsteroidal AR agonists, which would have potential in the treatment of diseases resulting from androgen deficiency, have just recently been reported. Still, the structural elements of nonsteroidal ligands that would lead to optimal agonist activity and tissue selectivity are poorly defined.
Non-steroidal propionanilides having androgen receptor modulating activity have been described e.g. in patent publications EP 100172, EP 253503, WO 98/53826 and WO 02/16310. The design of propionanilide structured AR modulators has concentrated on compounds where the anilide ring is substituted by two electron-withdrawing substituents such as halogen, cyano, trifluoromethyl or nitro, since such substitution has been reported to enhance the androgen receptor binding affinity of the ligand. See e.g. Tucker, H. et al., J. Med. Chem., 1988, 31, 954-959.

Propionamide derivatives useful as androgen receptor modulators

Abstract: Compounds of formula (I)

Abstract: wherein R1 to R4, X and A are as defined in the claims and pharmaceutically acceptable salts and esters thereof, are disclosed. The compounds of formula (I) possess utility as tissue-selective androgen receptor modulators (SARM) and are useful in hormonal therapy, e.g., in the treatment or prevention of male hypogonadism and age-related conditions such as andropause.


In some embodiments, during synchronizing of files in a source data set to a destination data set, a method receives a set of events that occurred at the source data set after replicating an image of the source data set to the destination data set. The method analyzes the set of events to determine if an exception to a first set of rules for performing a set of operators on the destination data set for the set of events occurs. A second set of rules for the exception is selected based on analyzing the set of events. The method processes the set of operators for the set of events according to the second set of rules to synchronize data from the first data set to the second data set based on the set of events. The processing of the set of operators uses the second set of rules.

In a data migration within a data center or to a new data center, a system migrates clusters of data, such as a distributed file system (e.g., a Distributed File System (HDFS) clusters (100-200 nodes)). When migrating clusters, one challenge is some clusters have different versions, such as vendor versions. For example, some files are stored on a first vendor's platform and other files are stored on a second vendor's platform. It requires a lot of work to maintain different versions of clusters, but the migration can be used to unify the cluster versions. That is, the system performs the migration that not only migrates the clusters, but switches their versions as well. However, this requires a file level migration that may take a lot of time to migrate.

Data cluster migration using an incremental synchronization


A system and process for muting the audio transmission from a location of a participant engaged in a multi-party, computer network-based teleconference when that participant is working on a keyboard, is presented. The audio is muted as it is assumed the participant is doing something other than actively participation in the meeting when typing on the keyboard. If left un-muted the sound of typing would distract the other participant in the teleconference.

1. Technical Field
The invention is related to multi-party, computer network-based teleconferencing, and more particularly to a system and process for muting the audio transmission of a participant using a keyboard during such a conference to prevent the other participants from hearing keyboard typing noise.
2. Background Art
Meetings are an important part of everyday life for businesses large and small. However, it is often inconvenient for meeting participants to be at the same location at the same time. When these distributed team members are not co-located, meetings are typically conducted using computer network-based teleconferences. A variety of live teleconferencing systems are available commercially to facilitate these meetings.
During these teleconferences, the participants tend to multi-task. For example, a participant may check or edit email, surf the web, and so on, while "attending" the meeting. In some situations, this multi-tasking is actually more efficient than attending the meeting all the time. The participant will only need to be attentive to the meeting when the discussion is relevant to the participant.
However, it has been observed that this multi-tasking typically involves the use of a computer keyboard, and conversely when the participant is actively participating in the meeting he or she is typically talking and not typing on their keyboard.
This keyboard activity by a multi-tasking meeting participant presents a problem. When a participant is typing on a keyboard, the typing sound will be captured by either a microphone associated with the participant's computer (if the teleconference audio is being handled via VoIP), or the participant's telephone (if the teleconference audio is being captured via a conventional telephone, and if a) the telephone PBX exposes APIs to control the phone or there is a dangle between the PC and phone so that the two can communicate). This is socially unacceptable, because other meeting participants will know that the participant is multi-tasking and not paying attention to the meeting, and the typing noise may be distracting to the other participants.
One solution can be for the multi-tasking participant to manually turn the audio transmission on and off. However, this is an impractical imposition on the participant and would restrict the participant's ability to spontaneously move between typing on the keyboard and talking with the other participants. The present invention resolves this dilemma, while still allowing a meeting participant to type on a keyboard and spontaneously participate in the meeting without having to manually turn the audio transmission on and off.

System and process for muting audio transmission during a computer network-based, multi-party teleconferencing session


A method of fabricating a semiconductor device. The method comprises creating a via in a dielectric layer that is formed on a substrate, filling the via, and optionally, the surface of the dielectric layer with a sacrificial material, patterning a first photoresist layer on the sacrificial material to define a trench for the semiconductor device, removing the first photoresist layer without affecting the sacrificial material, repatterning a second photoresist layer on the sacrificial material to define the trench for the semiconductor device, forming the trench, and removing the second photoresist layer and the sacrificial material completely after the trench is formed.

Integrated circuits are made by forming on a semiconductor substrate layers of conductive material that are separated by dielectric (insulation) layers. Vias and/or trenches are etched in the dielectric layers and are filled with a conducting material to electrically connect the separated conductive layers. The vias and/or trenches filled with the conductive materials may be referred to as interconnects.
Sacrificial materials (e.g., sacrificial light materials and organic BARC material) have been used in the fabrication of semiconductor devices, for example, in making dual damascene metal interconnects. Dual damascene metal interconnects may enable reliable low cost production of integrated circuits using sub 0.25 micron process technology. Before such interconnects can realize their full potential, however, problems related to the process for making them must be addressed. One problem involves the lithography for defining dual damascene vias and trenches. Sacrificial materials, BARC materials, and photoresist materials are used throughout the lithography processes. The ability to remove these materials is crucial for the semiconductor processing. Another problem relates to the selectivity of removing certain materials, which are used to make dual damascene devices, after or throughout the processes where the vias and trenches are etched. At times, it is crucial to remove a particular layer while not affecting another layer. Another problem yet, relates to removing the sacrificial materials used during processing.

Organic solvents having ozone dissolved therein for semiconductor processing utilizing sacrificial materials


Disclosed is a method for transmitting a common schedule message to a plurality of mobile terminals using a short message service (SMS) in a mobile terminal having an SMS function and a schedule function, and enabling a mobile terminal receiving the schedule message to record the received schedule message therein as a schedule. If a user selects a schedule transmission for transmitting a schedule registered in the mobile terminal to another mobile terminal, the mobile terminal converts a data format for the schedule into a data format of a schedule-recordable SMS message, and then transmits the schedule-recordable SMS message. To record a schedule, the mobile terminal receiving a schedule message converts a data format of the received SMS message into a format of schedule-recordable data and records the converted data therein as a schedule, if schedule recording is selected by the user.

1. Field of the Invention
The present invention relates generally to a user interface for a mobile terminal having a schedule function, and in particular, to a method for managing schedules.
2. Description of the Related Art
Commonly, a user always carries a mobile terminal with him or her, and frequently uses an electronic diary function, i.e., a schedule management function, among additional functions of the mobile terminal. In such a schedule management function, if a user selects a menu and then sets a date and a time of a schedule and an alert method, a mobile terminal raises an alert at the set time of the schedule in the alert method set by the user, and displays the recorded schedule contents for the user. In this way, the user can conveniently be notified of set schedule events.
Such a schedule function is chiefly useful for recording, as a schedule, the contents that the user desires to memorize, such as friends or parents' birthdays or various anniversaries, and reminding the user of such information that the user may otherwise forget. Among the contents that the user desires to record as a schedule, such schedules as festive days, election days, team dining, team meetings, friendship meetings, etc. are applied in common to the persons belonging to a particular group. Conventionally, in the case where one group has a common schedule, constituent members of the group must individually record the schedule in their own mobile terminals, even though the schedule is common to them.
Generally, the schedule being common to the persons belonging to a particular group can be notified over a telephone call or through a short message service (SMS). For example, when a certain group has a meeting, the SMS service is used to provide notice the meeting. Currently, the SMS service sends only text messages input by the user to the constituent members. In that case, some constituent members will manage their schedules by memorizing the message contents and inputting the contents to a scheduler or a personal information manager (PIM), while other constituent members may forget the contents after simply reading them. In some cases, the user may delete an SMS message by mistake and thus forget important schedule information. Therefore, when schedule information included in a received SMS message is important information, the user must set and manage a schedule or alert function after inconveniently inputting the schedule information to the scheduler or the PIM in person.
As described above, conventionally, users must annoyingly individually input even the common schedule in their own mobile terminals. Particularly, in the case where a common schedule is received with an SMS message, if the received SMS message has information on the schedule or special information that must be provided to users, the users must, inconveniently, each input the information in their individual scheduler or the PIM. In addition, the users may lose important information if they inadvertently delete the received SMS message. In order to solve such annoyance, a method for recording the contents of a common schedule in a convenient way is required.

Method for transmitting and recording schedule using short message service


A process for removing iron impurities from sand by treatment of an aqueous slurry of the sand with a chelating agent for iron cations.

Over 15 million tons of sand per year is mined from areas that contain various iron species. Sand mined for glass and semiconductor production must be freed from various impurities, especially iron. Glass and semiconductor manufacturers have strict iron specifications that most sand mines cannot meet without using iron removal procedures. Iron species such as limonite and hematite are a few examples of the impurities typically found in sand bogs. Both are species of Fe2O3. The iron compounds that normally stain sand particles or form conglomerates are one of the most difficult impurities to remove using conventional processes. At present, the mineral process industry typically utilizes attrition scrubbers to separate iron and sand under caustic conditions. The process consists of three pH adjustments where the influent pH is typically low (3–5) and must by adjusted to pH of 10 or greater. Then the scrubber effluent must be acidified to pH 2–3 to separate the tails and iron. After the separation, the water is neutralized to pH 7. However, this process often does not remove enough iron to increase the utility of the sand in glass and semiconductor production.
U.S. Pat. No. 4,405,588 discloses a method of removing iron impurities adhering to silica sand particles, comprising grinding the ore, washing and desliming the ground ore to remove the major part of the clay-type binder, attrition scrubbing the deslimed particles to release further amounts of binder, washing and desliming to remove the binder, drying and heating the ore particles, treating the hot particles with a chemical agent suitable for converting the iron impurities into water soluble iron compounds, attrition scrubbing the hot suspension of chemically treated particles to release the iron stains, and washing with cold water and desliming to recover the purified particles. The chemical agents disclosed are sulfuric acid, hydrochloric acid and caustic soda.
U.S. Pat. No. 5,334,364 discloses a process for purifying silica sand consisting of subjecting the sand to centrifugal rotation under dry conditions while simultaneously agitating the particles, and then eliminating the impurities from the sand particle mixture.


There is provided a secondary battery comprising a positive and a negative electrode and a nonaqueous electrolyte. The positive electrode is made by dipping an electrode comprising a positive active material such as LiMn.sub.2 O.sub.4, LiMnO.sub.2, LiCoO.sub.2, LiNiO.sub.2, LiFeO.sub.2 or .gamma.LiV.sub.2 O.sub.5, in a solution containing butyllithium, phenyllithium, or naphthyllithium. The negative electrode of the battery absorbs and desorbs lithium by charging and discharging, and the nonaqueous electrolyte contains a lithium salt. Also provided is a method of manufacturing a secondary battery comprising a nonaqueous electrolyte. The method comprises the steps of preparing an electrode group containing a positive electrode of LiMn.sub.2 O.sub.4, LiMnO.sub.2, LiCoO.sub.2, LiNiO.sub.2, LiFeO.sub.2 or .gamma.-LiV.sub.2 O.sub.5, as the active material, and a negative electrode which absorbs and desorbs lithium by charging and discharging, with a separator therebetween. The group is placed in a battery case, and to the case is added a solution containing butyllithium etc. The solution is removed and an organic electrolyte as a nonaqueous electrolyte is added to the battery case.

This invention relates to a secondary battery comprising a nonaqueous electrolyte, containing an improved positive active material, and a method of manufacturing the same.
Secondary batteries containing nonaqueous electrolytes with negative electrodes comprising lithium, lithium alloy or lithium compounds are expected to be of high voltage and high energy density, and have been the subject of intensive research.
Compounds such as V.sub.2 O.sub.5, Cr.sub.2 O.sub.5, MnO.sub.2, TiS.sub.2, etc. have been used as a positive active material in a secondary battery comprising a nonaqueous electrolyte.
Recently, Thackeray et al. reported that Li.sub.x Mn.sub.2 O.sub.4 could serve as a positive active material in a secondary battery comprising a nonaqueous electrolyte (Material Research Bulletin, 18 (1983), 461-472).
The relationship of the x value of Li.sub.x Mn.sub.2 O.sub.4 and the electromotive force is shown in FIG. 2. These data demonstrate that the potential curve has two flat parts, in the vicinity of 4 V and of 2.8 V. Accordingly, Li.sub.x Mn.sub.2 O.sub.4 can be used in a lithium secondary battery of the 4 V class, if it is charged and discharged along the flat part of 4 V, within the range of 3 V to 4.5 V. The opencircuit potential against x-value of another positive active material, Li.sub.x CoO.sub.2, is given in FIG. 3. Since the potential curve exhibits flat parts in the vicinity of 4.0 V and of 1.2 V, Li.sub.x CoO.sub.2 can also be used in a lithium secondary battery of the 4 V class, by charging and discharging at the flat part of 4 V. Regarding the negative electrode, lithium metal has been the target of research investigations. However, a negative electrode of lithium has disadvantages in that when charged, a dendrite lithium is generated on the surface thereof and, following repeated cycles of charging and discharging, a low charging-discharging efficiency or shortcircuiting within the battery was observed which was due to the contraction of the positive electrode. This led to research on negative active material holders such as carbon, aluminum or its metal or alloy, or other kinds of oxides which absorb and desorb lithium in the absence of accumulation of dendrite.
In a secondary battery comprising carbon or aluminum as the negative active material holder, LiMn.sub.2 O.sub.4, LiMnO.sub.2, LiCoO.sub.2, LiNiO.sub.2 LiFeO.sub.2 or .gamma.-LiV.sub.2 O.sub.5 as the positive active material, and a non-aqueous organic electrolyte such as lithium perchlorate organic solvent solution, the first charging causes lithium ions to be released from the positive active material and to be absorbed by the negative active material, and the subsequent discharge causes the transfer of lithium from the negative active material to the positive active material. The lithium ions taking part in the battery reaction are confined solely to the ions which existed in the positive electrode at the beginning of the cycle. These ions therefore determine the capacity of the battery. In a battery comprising the above described negative active material, the lithium which is absorbed by the negative active material during the first charging cycle is not necessarily released during the subsequent discharging event. (The amount of lithium absorbed by the negative active material is greater than that released by the negative active material: this is the charging-discharging capacity difference). When lithium is taken up by the negative active material but does not participate in the remaining events in the battery, the number of lithium ions capable of cycling during charging and discharging is decreased, resulting in a decline in battery capacity.
In order to enhance the lithium capacity of the negative active material holder, use of Li.sub.x Mn.sub.2 O.sub.4 , Li.sub.x MnO.sub.2 Li.sub.x CoO.sub.2, Li.sub.x NiO.sub.2, Li.sub.x FeO.sub.2, or .gamma.-Li.sub.2 V.sub.2 O.sub.5 (x>1) as the positive active material containing an excess of lithium ions has been proposed.
In order to synthesize these materials, methods have been developed to add excess lithium salt to the raw material of each compound, or alternatively the lithium content of the positive active material can be increased by the addition of butyllithium (Japanese Patent Application Laid-Open, No. Toku-Kai-Hei 2-265167). Regarding the former method, however, Li.sub.x Mn.sub.2 O.sub.4 , Li.sub.x MnO.sub.2, Li.sub.x CoO.sub.2, Li.sub.x NiO.sub.2, Li.sub.x FeO.sub.2 or .gamma.-Li.sub.x V.sub.2 O.sub.5 (x>1) obtained by the addition of excess lithium by heating, react with moisture in the air and decompose to form LiMn.sub.2 O.sub.4, LiMnO.sub.2, LiCoO.sub.2, LiNiO.sub.2, LiFeO.sub.2 or .gamma.-LiV.sub.2 O.sub.5 and LiOH or the like. Thus, these compounds (Li.sub.x Mn.sub.2 O.sub.4 etc.) cannot tolerate the application of water as a solvent during pulverization or classification after synthesis. Instead, the processes must be carried out in air, or inert gas without moisture. Regarding the second method wherein the positive active material is doped with lithium by dipping the material powder, after synthesis, into butyllithium as a lithium-adding liquid, the positive active material containing excessive lithium is unstable in a moist atmosphere. Thus, these steps must also be carried out in a dry atmosphere using a nonaqueous solvent.

Secondary battery with nonaqueous electrolyte and method of manufacturing same

Matsushita Electric Industrial Co., Ltd.


Software code of a software program is executed in a multi-processor computer environment. The software code includes a first portion and a second portion. The first portion is executed in a computer. The second portion is executed in one or more tamper-resistant external devices which are in communication with the computer. The second portion includes a plurality of different blocks of code. At least some of the blocks have sequence data associated therewith. If sequence data exists in the current block of code to be executed in the one or more external devices, then the sequence data is used to determine if execution of the block of code is permissible or should be inhibited. The sequence data includes predecessor data and successor data.

The present invention describes a mechanism for the protection of the correct execution-order of interdependent (interrelated) software applications. In particular, the present invention relates to software license protection for the shielded and timely execution of software applications through the use of tamper-resistant external devices, such as smart cards, USB tokens or other forms for tamper-resistant environments. The present invention also finds its applications in any traditional smart card security application area, such as e-payment, digital rights management (DRM), multi-media protection, authentication, biometry, public-key infrastructure (PKI), encryption-schemes, as an integrated part of special-purpose secure operating systems for tamper-resistant external devices, and the like. The present invention relates to International Application No. PCT/NO96/00171 designating the United States, now U.S. Pat. No. 6,266,416 (Sigbjormsen et al.), which is incorporated by reference herein. This patent describes a system for software license protection through the partial execution of a software application in a tamper-resistant external device.
In multi-processing computer environments, such as for example that provided by a dual-processor environment consisting of an (untrusted) host computer and a (trusted) external, tamper-resistant device such as a smart card or other token, software applications residing on the host computer are sometimes required to make more than one finction call to applications residing on the external device. Software applications which execute on external devices as described herein are also referred to as xe2x80x9capplets.xe2x80x9d Generally speaking, the path of execution of a software application, whether that be a host application or an external device/smart card applet, is critical for the correct functioning of the application. It is important that the execution path is not tampered with.
As a trivial example, an application which converts Celsius temperature degrees into Fahrenheit would need to perform the equation F=9/5*C+32. The multiplication of the Celsius degree by 9/5 must be carried out before the addition by 32. According to the prior art, correct execution order is ensured by letting the function in its entirety be executed in a tamper-proof environment, as an applet, allowing just one function-call entry from the host application to the applet. Since the applet resides on the tamper-resistant smart card, it may not be tampered with, and since the applet has just one entry-point, there is no way the addition operation can possibly be performed before the multiplication operation. Functional atomicity, integrity and correct execution order has been ensured.
If the function F=9*C/5+32 nonetheless was to be split into three applets, as illustrated in FIG. 1; applet 1 as i=9*C, applet 2 as i=i/5 and applet 3 as F=i+32, each with a separate function entry point, then, according to the prior art, no mechanism allows the external device to discover and hinder an adversary from modifying the host application by reversing applet function calls towards the external device, e.g., calling applet 3 before applet 1, or by removing one or several calls, to thereby break the integrity of the compound smart card application.
FIG. 2 shows a scenario where the adversary has removed the call to applet 2, causing the external device to return a corrupt result. Thus, a tamper-proof device does not in general suffice to maintain the correct execution order and overall applet integrity.
A first objective of the present invention is to provide an integrity protection mechanism that allows a smart card application to be split into more than one sub-applications in a safe manner, enforcing correct execution order and application integrity, and to allow the execution environment of the external device to discover any attempts to process applets in an illegal order or manner. This facility opens up new technological possibilities. A second objective of the present invention is to facilitate, for the purposes of software license protection and other application areas indicated above, the selection of software application components suitable and not suitable for execution on the tamper-resistant device, in an unconstrained manner, thereby providing an efficient and highly user-friendly tool for optimization of application security and performance.

Sequence numbering mechanism to ensure execution order integrity of inter-dependent smart card applications


An internal combustion engine exhaust modification system for transforming exhaust emissions from an internal combustion engine into modified exhaust emissions. The exhaust modification system includes a housing extending between inlet and outlet ends thereof. The system also includes an impeller rotatably mounted in the housing, and a filter subassembly downstream from the impeller. The filter subassembly removes part of particulate matter and liquid droplets in the exhaust emissions to transform the exhaust emissions into modified exhaust emissions. The system includes a conduit extending between an inner end thereof positioned to direct cooler air exiting therefrom into the housing toward the filter subassembly, and an outer end thereof. The system also includes a funnel subassembly having a funnel body for directing the cooler air into the outer end of the conduit.

As is well-known in the art, the exhaust produced by an internal combustion engine typically includes a variety of gases, particulate, and some fluids (e.g., droplets of motor oil and unburned fuel) that are directed into an exhaust system. In general, known exhaust systems do not prevent the gases and unconsumed fluids from exiting the exhaust systems.

Internal combustion engine exhaust modification system


Methods and apparatus described herein may utilize activation of an SMP material to install medical devices with respect to a surgical site. Activation of the SMP material may be performed with the use of a triggering force and/or a constraint applied to the SMP material. Activation using a triggering force and/or a constraint may be used to create varied activation rates in an SMP material and may be combined with temperature or other activation stimuli to create the varied activation rates.

Medical personnel use a variety of implantable medical devices in a patient to position, fix, hold, and otherwise manipulate a patient's body. The installation procedures for such implantable medical devices may be advantageously designed to allow medical personnel to install the medical device quickly, effectively, and consistently. The design of the medical device may actually facilitate and/or simplify the installation procedure. Furthermore, the design of a medical device may facilitate a particular installation procedure. Active elements of a medical device, including shape memory polymer portions, may be incorporated in medical devices. A shape memory polymer (SMP) may be activated to induce shape change and/or to generate forces against constraints surrounding the SMP. Medical devices comprising SMP portions may utilize activation of the SMP portion to change the configuration of the medical device to an installed configuration with respect to a surgical site and/or to generate forces against the surgical site.

Method and apparatus for deploying a shape memory polymer


A buckle having an adjustable loop end forming a primary plane with opposing side walls. The adjustable loop end has a central bar positioned between a first strap opening and a second strap opening. A pair of slots operable to receive the terminal ends of the central bar are recessed into the interior surface of the opposing side walls with the bottom edges of the slots being longer than the top edges. A pair of tabs on opposite ends of the central bar extend outward from the central bar along a longitudinal axis of the primary plane and towards the second strap or belt opening. Optionally, a protrusion extends from a lower surface of the fixed loop end wherein the protrusion is positioned at a right angle with respect to a vertical axis of the primary plane.

Various adjustable strap fasteners or buckles are known in the prior art which may be manipulated to adjust the effective length of a strap as used on, for example, a safety harness line. Such fasteners are usually made of a plastic or metal material and formed into an integral molded structure which generally comprises a fixed loop end and adjustable loop end. In use, one strap end portion is looped through a strap or belt opening on the fixed loop end and secured in place as by stitching or rivetting. The other strap end portion which is adapted for length adjustment is looped through one belt or strap opening on the adjustable loop end, around a central cross bar and looped back through a second strap or belt opening on the adjustable loop end and frictionally gripped therebetween against displacement.
The belt buckles known in the prior art are not able to withstand higher loads and pressure against the adjustable loop central cross bar. Further, these buckles are not easily worn close against the body of a user as they tend to flip upwards when a force is applied against them


An image display device includes: a light transmitting unit having transmission wavelength characteristics corresponding to each of a plurality of colors; an illuminating unit configured to emit light corresponding to each of the plurality of colors, the illuminating unit being configured to emit, with respect to at least one predetermined color, light including first light and second light whose emission peak wavelengths are both within a range of the transmission wavelength characteristics corresponding to the predetermined color and whose emission peak wavelengths differ from one another; and a control unit configured to control an intensity of each of the light of the plurality of emission spectra corresponding to the predetermined color in accordance with a color distribution of the image.

Field of the Invention
The present invention relates to an image display device which forms an image using a light source and an optical modulator that modulates transmittance or reflectance of light incident from the light source per pixel according to a drive signal, and a control method of the image display device.
Description of the Related Art
Color matching functions that represent human visual characteristics related to color are known to have individual variability attributable to fluctuations caused by age and the like. CIE170-1 is proposed as a model of such a fluctuation by the International Commission on Illumination (CIE).
The existence of such individual variability sometimes causes color to appear subtly different on an image display device from person to person. As a result, there may be cases where, depending on an observer, a color does not appear to be matched even after performing color calibration for colorimetric matching with printed matter. This phenomenon is particularly prominent among display devices using light sources with a narrow spectrum as a backlight in order to expand a display color gamut.
In order to solve this problem, there is a method of reducing individual variability of the appearance of color by reproducing a color spectrum of the real world as faithfully as possible on the basis that image signals and display devices have six primary colors (Japanese Patent Application Laid-open No. 2003-141518).
Alternatively, a display device is proposed that combines a broad light source which has a broad emission spectrum and which is used when an image to be displayed has low chroma and a narrow light source which has a narrow emission spectrum and which is used when an image to be displayed has high chroma (Japanese Translation of PCT Application No. 2012-515948). The display device is designed to achieve both a reduction of individual variability in appearance of color and an expansion of a display color gamut.
In addition, a method of expanding a color gamut of a display device by simultaneously lighting, in addition to an RGB basic light source, an extended light source of a different color is proposed (Japanese Patent Application Laid-open No. 2012-47827).
Furthermore, a method of expanding a color gamut of a display device by changing an applied current value of an RGB basic light source per factice field to increase the number of colors of the light source is proposed (Japanese Patent Application Laid-open No. 2005-275204).
Moreover, an image display device is proposed which is configured such that two light sources are provided for one color of a color filter, the two light sources belong to a same color category, and two peak wavelengths that differ from each other of the two light sources both fall within a wavelength range of transmission characteristics of the color filter (Japanese Patent Application Laid-open No. 2004-138827).

Image display device and control method thereof


An electrical connector and a terminal thereof are provided. The electrical connector comprises a housing, a circuit board and a plurality of terminals. The housing comprises a body and an assembly frame. The body is formed with a first surface and a second surface which are opposite to each other, and includes a terminal mounting hole penetrating through the first surface and the second surface. The assembly frame extends outwardly from the second surface and forms a mounting surface. The circuit board is mounted to the mounting surface. The terminal comprises a main body, a plurality of pins and a pressing portion. The main body is mounted to the corresponding terminal mounting hole. The pins protrude out of the first surface from a side edge of the main body adjacent to the first surface.

Electrotherapy is a common therapeutic method in modern medicine. Using various currents having different frequencies to stimulate body tissues of patients can produce various medical effects including changing transfer function of peripheral nerve fibres, stimulating hormone secretion, and promoting tissue healing and the like. However, in various electrotherapy devices, a needle-like electrode medical device is often used to pierce into skin of a patient so as to perform a deeper and effective discharge treatment on the tissue of the patient. Moreover, the needle-like electrode can also be used for a medical detection.
An existing conventional technology, for example a U.S. Pat. No. 4,685,466 and a U.S. Pat. No. 8,086,322 (corresponding to a Chinese patent application No. CN200580042302.4), typically comprises a mounting and a plurality of needle-like electrodes fixed to the mounting. When the needle-like electrode device is manufactured, firstly the each needle-like electrode is inserted into the mounting one by one, then a plurality of conductors are respectively soldered to individual needle-like electrodes and a printed circuit board or a cable, finally, the each needle-like electrode and a medical device controlling current are electrically connected via the printed circuit board or the cable. Therefore, when the existing needle-like electrode device is manufactured, the each needle-like electrode not only is required to manufacture separately, but also needs a one-by-one inserting process on the mounting, then the each needle-like electrode and the corresponding conductor are soldered to each other. In the above manufacturing process, not only a highly precise positioning technology is need but also a manufacturing process is not easy, and the one-by-one inserting process results in a low manufacturing efficiency, meanwhile manufacturing cost is also increased; moreover, the elongated needle-like configuration needs a plurality of connections and adapters to be connected to the circuit board or the device, which also increases the manufacturing difficulty and the manufacturing cost. Therefore, the existing needle-like electrode device still has a room for improvement. Moreover, such the piercing invasive device is typically desired to be replaced and discarded after a disposable use, so the configuration needs to be more easily used, and needs to be cheaper.