Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2000-06-21
2003-12-09
Shankar, Vijay (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S174000
Reexamination Certificate
active
06661399
ABSTRACT:
CROSS REFERENCE
This application claims the benefit of Korean Patent Application No. 1999-23168, filed on Jun. 21, 1999, under 35 U.S.C. §119, the entirety of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a liquid crystal display device having a digitizer.
2. Description of Related Art
Liquid crystal display (LCD) panels are used in many electronic data handling devices, including lap-top computers, personal digital assistants, personal organizers, and point-of-sale terminals. Some display systems include the ability of inputting information directly onto the display screen by pointing or writing with a finger or a stylus. For example, a finger may be used to push a “soft” button that is displayed on the screen, or a stylus can be used to sign one's name and have it captured and displayed electronically.
An LCD panel, shown in
FIG. 1
, comprises a liquid crystal display (LCD) module “L” and a digitizer “D”. The LCD module “L” has lower and upper substrates
10
and
20
with an interposed liquid crystal layer
13
. The lower substrate
10
has switching elements (not shown), such as thin film transistors (TFTs), and the upper substrate
20
has a common electrode, a color filter and a black matrix. A linear polarizer
22
is located on the upper substrate. The lower and upper substrates
10
and
20
are sealed by a sealant
12
to prevent leakage of the liquid crystal. Further, pads (not shown) patterned on the lower substrate
10
are electrically coupled to a printed circuit board (PCB)
14
through a TCP (tape carrier package)
17
having a film
18
carrying a drive integrated circuit (IC)
19
. Pads (not shown) on the lower substrate
10
and output signal lines of the film
18
are electrically connected with an anisotropic conductive film
16
a
, and signal lines of the PCB
14
and input lines of the filml
8
are electrically connected with an anisotropic conductive film
16
b.
Furthermore, the digitizer “D” is a location-sensing component having first and second plates
24
and
26
, and a drive circuit
25
(see FIG.
4
). The plates
24
and
26
serve to produce or detect signals indicative of the location of a stylus, a finger, or another input device. Each of the plates
24
and
26
has a substrate, a transparent electrode, and a metal pattern layer that are stacked in that order. Further, as shown in
FIG. 2
, which is a plan view of the first plate
24
of the digitizer “D”, the first plate
24
has a plurality of regularly spaced digitizer electrodes
28
formed along the edges of an active region
32
. The digitizer electrodes
28
are connected to an external digitizer drive circuit (not shown). The active region
32
is a location sensing region having a resistive layer in the form of a strip or a grid.
Further, the drive circuit
15
for the LCD module “L” shown in
FIG. 3
comprises a power supply
15
a
for supplying a voltage, a clock generator
15
b
for producing clock signals to drive the LCD device, a gamma circuit
15
c
for collecting a gamma characteristic of the LCD device, a controller
15
d
for controlling all components of the LCD module “L”, and data and gate drivers
15
e
and
15
f
for producing images. Further, the drive circuit
25
for the digitizer “D” shown in
FIG. 4
comprises a power supply
25
a
for supplying a voltage, a clock generator
25
b
for producing clock signals to drive the digitizer, a controller
25
c
for controlling all components of the digitizer “D”, an analog to digital (A/D) converter
25
d
for converting analog signals to digital signals, an input/output (I/O) unit
1
25
e
for conveying analog signals from the digitizer to the A/D converter
25
f
and conveying signals from the controller
25
d
to the digitizer, and an input/output (I/O) unit
2
25
f
for transferring digital signals in the form of x and y coordinate values from the AID converter
25
d
to a main system of the device having the LCD device such as notebook computer by the controller
25
c.
However, the LCD panel described above has disadvantages. First, as shown in
FIG. 2
, since a plurality of wires
30
are directed along one direction for connection with the external drive circuit
25
, the wires
30
differ in length, thereby causing different RC delays. Second, as shown in
FIGS. 3 and 4
, the digitizer “D” and the liquid crystal display module “L” use different drive circuits
15
and
25
even though they have some similar elements, such as a power supply, a controller and a clock generator. Multiple similar elements increase the production cost of an LCD device with a digitizer. Furthermore, multiple similar elements make it difficult to achieve a compact LCD panel.
SUMMARY OF THE INVENTION
To overcome the problems described above, preferred embodiments of the present invention provide a liquid crystal display (LCD) device having a digitizer in which the drive circuit for the digitizer is integrated with the drive circuit for the LCD device.
Another object of the present invention is to provide a compact LCD device.
Another object of the present invention is to provide a low cost LCD device.
To achieve the above objects, the present invention provides a liquid crystal display device having a digitizer, including: a first frame; a liquid crystal panel supported by the first frame, the liquid crystal panel having a display region and a side wall portion; a digitizer located on the liquid crystal panel, the digitizer having a peripheral portion; and a second frame having a front surface with an opening region and a side wall portion, the front surface pressurizing the peripheral portion of the digitizer, and the opening region formed at a location corresponding to the display region of the liquid crystal panel.
The liquid crystal display device of the present invention further includes a printed circuit board having a drive circuit for driving the digitizer; and a first connection electrically connecting the printed circuit board with the digitizer, with the first connection passing between the side wall portion of the liquid crystal panel and the side wall portion of the second frame.
The liquid crystal display device further includes a printed circuit board located on a back surface of the first frame, the printed circuit board having a controlling circuit for controlling both the liquid crystal panel and the digitizer.
The digitizer includes a plurality of digitizer electrodes covered by the front surface.
The present invention also provides a liquid crystal display device used by a main system, including: a digitizer for producing signals indicative of the location of an external input and driven according to a first clock generated by a first clock generator; a liquid crystal display device for displaying predetermined information according to signals from the digitizer, the liquid crystal display device having first and second substrates with an interposed liquid crystal layer, and data and gate lines; and a printed circuit board having a controlling circuit for controlling the digitizer and the liquid crystal display.
The drive circuit includes a power supply for supplying a voltage to the LCD panel and the digitizer; a clock generator for producing clock signals to drive the LCD device and the digitizer; an analog to digital (A/D) converter for converting analog signals to digital signals; a gamma circuit for correcting gamma characteristics of the LCD device; a first input/output (I/O) unit for conveying analog signals to the A/D converter and conveying signals from the controller to the digitizer; a second input/output (I/O) unit for transferring digital signals in the form of x-y coordinate values from the AID converter to the main system; data and gate drivers driven by the clock generator; and a controller for controlling all components of the drive circuit.
The first I/O unit is beneficially a serial port, a parallel port, a universal serial bus (USB), or an IEEE
Ahn Young-Soo
Jeong Yun-Cheol
Oh Young-Jin
LG.Philips LCD Co. , Ltd.
McKenna Long & Aldridge LLP
Shankar Vijay
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