Source: http://www.google.com/patents/US6137482?dq=6076065
Timestamp: 2017-11-22 04:01:03
Document Index: 178251469

Matched Legal Cases: ['art.\n4', 'art.\n6', 'art 43', 'art 43', 'arts 44', 'art 44', 'art 43', 'art 44', 'art 61', 'art 62', 'art 62', 'art 62', 'art 62', 'art 63', 'art 91', 'art 91', 'art 91']

Patent US6137482 - Position sensible liquid crystal display device - Google Patents
A position sensible liquid crystal display (PSLCD) device capable of automatically compensating for potential distribution distortions in a driving signal has a signal correcting part disposed between a switching part and the position sensing substrate for adjusting the driving signal to correct for...http://www.google.com/patents/US6137482?utm_source=gb-gplus-sharePatent US6137482 - Position sensible liquid crystal display device
Publication number US6137482 A
Application number US 08/992,669
Publication number 08992669, 992669, US 6137482 A, US 6137482A, US-A-6137482, US6137482 A, US6137482A
US 6137482 A
A position sensible liquid crystal display (PSLCD) device capable of automatically compensating for potential distribution distortions in a driving signal has a signal correcting part disposed between a switching part and the position sensing substrate for adjusting the driving signal to correct for the potential distribution distortions. The position sensing function is performed using a black matrix grid in the substrate.
a first substrate having a plurality of gate lines, data lines, thin film transistors, and pixels arranged thereon;
a second substrate having a digitizer formed of first and second grids and a signal applying area;
a switching part under the control of the microcomputer for selecting a driving AC signal and a grounding signal; and
a signal correcting part connected to the switching part for selecting one level among a plurality of predetermined amplitude levels of the AC signal and for applying the selected one level to the signal applying area to compensate a potential distribution of the digitizer.
3. A device as claimed in claim 2, wherein the signal correcting part includes:
an amplifying part for amplifying a signal from the switching part, and
a variable resistor for adjusting an output value fed back from the amplifying part to adjust an amplitude of the signal provided to the driving signal applying part.
4. A device as recited in claim 1, wherein the signal correcting part includes,
an amplifying part for amplifying a driving AC signal; and
an amplification gain determining and selecting switch for dividing the signal from the amplifying part into a plurality of voltage levels, selecting one of the plurality of voltage levels, and providing the selected voltage level to the signal applying part.
6. A device as claimed in claim 1, wherein the amplification gain determining and selecting switch includes,
a plurality of resistors for dividing the signals from the amplifying part into a plurality of voltage levels; and
a multiplexer connected to the resistors for selecting one of the plurality of voltage levels.
9. A position sensible display device comprising:
a digitizer of a rectangular shape and having four signal applying areas at corners; and
a driving circuit selectively for applying an AC signal to two adjacent signal applying areas and a grounding signal to the other two signal applying areas, the driving circuit including,
a driving signal generating part for generating a driving AC signal,
a switching part for selecting the driving AC signal and grounding signal, and
a signal correcting part coupled to the switching part for selecting one level among a plurality of predetermined amplitude levels of the AC signal and for applying the selected one level to the applying area to compensate the potential distribution of the digitizer.
Accordingly, the present invention is directed to a method for driving a PSLCD device that substantially obviates one or more of the limitations and disadvantages of the related art.
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. FIG. 4 illustrates a PSLCD in accordance with a first preferred embodiment of the present invention and includes a PSLCD panel 41; driving signal applying area 42 disposed at four corners of the PSLCD panel 41; a switching part 43 for selective application of a driving AC signal or a grounding signal to the driving signal applying areas 42; and signal correcting circuits 44, each for receiving a signal from the switching part 43 and compensating the signal for potential distribution error that may occur in the PSLCD. Each of the signal correcting parts 44 includes an amplifying part 44a, such as an operational amplifier, for receiving and amplifying the driving AC signal or the grounding signal from the switching part 43, and a variable resistor 44b for adjusting a signal fed back to the amplifying part 44a to thereby adjust an amplitude of the signal provided to the driving signal applying areas 42.
Referring to FIG. 6, the driving AC signal from the driving AC signal generating part is amplified by an appropriate gain through the first amplifying part 61 and provided to the amplification gain determining and switching part 62. Then, the amplified driving AC signal passes through the initial resistor R3 and is provided to terminal X0 of switching part 62b. The plurality of resistors connected in series between the resistor R3 and terminal X7 divide the amplified driving AC signal into the plurality of levels. Switching part 62b selects one of terminals X1 -X7 using control signals D0, D1, and D2 from a microcomputer (not shown) to select the appropriate voltage level.
The aforementioned second embodiment of the PSLCD device of the present invention will be explained in more detail with reference to FIG. 7. Assume coordinates of points "a", "b", "c" and "d" on the conventional PSLCD panel are taken with a stylus and the coordinates values (i.e., voltage values taken by the stylus with reference to a central point 0) are as shown in FIG. 8. As shown, the voltage at point "a" is Va, the voltage at point "b" is Vb, the voltage at point "c" is Vc and the voltage at point "d" is Vd. The voltage pairs (Va, Vb) and (Vc, Vd) are not identical. However, with the second embodiment of the present invention, the voltages of Va and Vb, and of Vc and Vd can be compensated to make them identical. In particular, consistent with the present invention, it is assumed that Vc/Vd equals a constant (called alpha). Accordingly, by amplifying Vc and/or Vd based on the amplification factor of terminals X0 -X7, from switching part 62b, Vc/Vd can be made equal to one. Then, the voltage selected in response to the control signal is provided to the PSLCD panel through second amplifying part 63. Similarly, amplification factors are selected so that Vb/Va becomes unity. Thus, by adjusting an amplitude of the driving AC signal, i.e., a peak-to-peak voltage in case of a sinusoidal wave, amplitudes of voltages taken by the stylus at points in distances equal from an origin can be compensated to be equal.
FIG. 9 illustrates a system of a PSLCD device in accordance with a third preferred embodiment of the present invention. This embodiment is similar to the second embodiment, except that here, selectable amplification gain is provided at a fore end of an amplifier. That is, the third embodiment of the PSLCD device consistent with the present invention includes an amplification gain determining and switching part 91 for providing a driving AC signal only to one of a plurality of resistors R22 -R29 to provide appropriate amplification gain for voltage distortion compensation. In this instance, the amplification gain is - (R30 /Rn), where n=22, 23, - - - , 29. The amplification gain determining and switching part 91 includes a switching part 91a having a plurality of analog switches for selectively switching the driving AC signal and resistors 91b respectively connected to the switches for dividing the driving signal provided through the switches to a plurality of levels.
US6823481 * Mar 6, 2001 Nov 23, 2004 Ricoh Company, Ltd. Optical coordinate input/detection device with optical-unit positioning error correcting function
U.S. Classification 345/179, 345/178, 345/104
International Classification G09G3/36, G06F3/041, G06F3/033, G02F1/13, G02F1/133
Cooperative Classification G06F3/0418, G09G3/3655, G06F3/0412
European Classification G06F3/041T2, G06F3/041D, G09G3/36C8C
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KIM, JUN HEE;REEL/FRAME:010762/0977