Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2000-09-25
2002-05-07
Chang, Kent (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S087000, C345S098000
Reexamination Certificate
active
06384807
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to a driving method and a driving circuit of a liquid crystal display employed in an information processing apparatus such as a personal computer. More specifically, the present invention is directed to an LCD (liquid crystal display) driving method/circuit capable of applying equal drive voltages to pixel elements on a horizontal line.
Conventionally, various LCD structures and LCD driving methods/circuits have been proposed. For instance, as to the structure/driving method of the TFT (thin-film transistor) liquid crystal panel, “Multi-Color Technique for TFT Color Liquid Crystal Display, from 4096 colors to 260,000 or more Colors”,
Flat Panel Display
'91, pp. 173-180, published by Nikkei BP on Nov. 26, 1990, describes the LCD driving method with employment of the high withstanding voltage drain driver. Also, JP-A-57-49995 (1982) describes the method for converting common electrode voltages into AC voltages with employment of the low withstanding voltage drain driver. A high withstanding voltage drain driver implies a drain driver with such a withstanding voltage capable of producing voltages to obtain maximum luminance and minimum luminance having a positive polarity and a negative polarity with regard to one electrode voltage of a liquid crystal display. A low withstanding voltage drain driver implies a drain driver with one withstanding voltage capable of obtaining maximum luminance and minimum luminance having either a positive polarity or a negative polarity (namely, “a single polarity”), and also with the other withstanding voltage not capable of obtaining maximum luminance and minimum luminance having both positive
egative polarities.
The above-explained two typical conventional driving methods will now be described more in detail.
First, the LCD driving method with employment of the high withstanding voltage drain driver will now be explained with reference to FIG.
5
and
FIGS. 24
to
27
.
FIG. 24
schematically represents a system structural diagram of the conventional liquid crystal display apparatus with employment of the high withstanding voltage drain driver.
In
FIG. 24
, reference numeral
101
is a system bus for transferring digital display data and a synchronization (sync) signal. In this example, it should be noted that both the display data and the sync signal transferred in the system bus
101
are line sequential scanning signals similar to the display data and the sync signal transferred to be displayed on the CRT (cathode-ray tube) display apparatus. Reference numeral
102
denotes a liquid crystal display controller for converting the digital display data and the sync signal transferred by the system bus
101
into digital LCD data and a timing signal for driving the liquid crystal display apparatus. Reference numerals
103
,
104
,
105
represent reference voltages in which
103
is a digital-low drive voltage V
EE
,
104
is a digital-high drive voltage V
CC
, and
105
is DC voltages having various LCD drive voltages. Reference numerals
106
and
107
denote signal drive circuit control buses for transferring both of the digital LCD data and the timing signal which have been converted for the signal drive circuit under control of the LCD controller
102
. Reference numeral
108
is a scanning drive circuit control bus used to transfer a timing signal for a scanning drive circuit. Reference numeral
109
shows an LCD alternating signal which becomes a timing signal for alternating a polarity of a voltage applied to a liquid crystal display. Reference numerals
2401
and
2402
represent signal drive circuits for acquiring the digital LCD display data transferred via the respective signal drive circuit control buses in response to the timing signal and for converting the display data into LCD voltages corresponding to the LCD display data. Reference numerals
116
and
117
show signal lines for transferring the LCD apply voltages VDC, VDL produced in the respective signal drive circuits
2401
and
2402
. Reference numeral
118
is a scanning drive circuit and reference numeral
119
is scanning lines. The scanning drive circuit
118
sequentially causes the scanning lines
119
to be active in response to the timing signal transferred via the scanning drive circuit control bus
108
. Reference numeral
120
is a liquid crystal display panel. Reference numeral
2403
is a reference DC voltage producing circuit for producing various DC reference voltages used to operate this LCD apparatus. Reference numeral
122
shows a DC voltage line used to the scanning drive circuit, for applying a DC voltage to the scanning drive circuit
118
. Reference numeral
123
denotes a common (opposing) electrode line for transferring a DC common voltage VCOM. Reference numeral
2402
denotes a reference voltage line for transferring a high-level reference voltage VCC for driving signal drive circuits
2401
and
2402
, reference numeral
2405
is similarly a reference voltage line for transferring a low-level reference voltage VEE, and reference numeral
2406
denotes a reference voltage line of a LCD drive unit, for transferring a LCD drive voltage VCCD used to drive the LCD drive circuit unit among the signal drive circuits
2401
and
2402
. Any of the reference voltages transferred via the reference voltage lines
2404
,
2405
,
2406
are DC voltages. Reference numeral
125
shows a DC LCD apply voltage for the signal drive circuit. Reference numeral
131
denotes an AC circuit. Reference numeral is an LCD drive voltage line used to transfer the AC LCD drive voltage employed in the upper-sided signal drive circuit
2401
, whereas reference numeral
133
is an LCD drive voltage line used to transfer the AC LCD drive voltage employed in the lower-sided signal drive circuit
2402
.
FIG. 25
is a schematic block diagram for showing an example of the signal drive circuit
2401
of FIG.
24
. It should be noted that the signal drive circuit
2402
for the lower side of the LCD panel
120
has a similar arrangement to that of this signal drive circuit
2401
.
In
FIG. 25
, reference numerals
2501
-
1
,
2501
-
2
, - - - denote drain drivers, and the signal drive circuit
2401
is arranged by a plurality of drain drivers
2501
. The drain driver
2501
is so arranged that the digital LCD display data is inputted and converted into a LCD apply voltage which will then be outputted. Among the signal drive circuit control bus
106
, reference numeral
2502
is a shift clock, reference numeral
2503
is a latch clock, and reference numeral
2504
is an LCD display data bus. The shift clock
2502
is synchronized with the digital LCD display data transferred via the LCD display data bus
2504
, whereas the latch clock
2503
becomes active after the digital LCD display data for 1 line has been transferred to the signal drive circuits
2401
and
2402
. Reference numeral
2505
is a shift register and reference numeral
2506
is a latch signal. The shift register
2505
accepts the shift clock
2502
to perform the shift operation. The latch signal
2506
sequentially becomes active in response to this latch operation. Reference numeral
2507
shows a latch circuit for successively latches the digital LCD display data transferred via the LCD display data bus
2504
. Reference numeral
2508
denotes a data bus for transferring data latched by a latch circuit
2507
. Reference numeral
2509
represents a latch circuit for latching data transferred via the data bus
2508
. Reference numeral
2510
is a data bus for transferring the data latched by the latch circuit
2509
. Reference numeral
2511
is a level shifter for converting a voltage amplitude level of digital data transferred via the data bus
2510
. Reference numeral
2513
is a digital-to-analog converting circuit for converting the digital data via the data bus
2512
into a liquid crystal apply voltage based on the AC voltage transferred via the AC LCD drive voltage line
132
. Reference numeral
116
is a signal line for transferring the
Furuhashi Tsutomu
Futami Toshio
Ikeda Makiko
Kasai Naruhiko
Suzuki Tetsuya
Antonelli Terry Stout & Kraus LLP
Chang Kent
LandOfFree
Liquid crystal display driving method/driving circuit... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal display driving method/driving circuit..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal display driving method/driving circuit... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2881815