Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2001-07-23
2004-11-09
Williams, Joseph (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
Reexamination Certificate
active
06814642
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a flat panel display and, more particularly, to a flat panel display with a touch screen.
BACKGROUND OF THE INVENTION
Modem electronic devices provide an increasing amount of functionality with a decreasing size. By continually integrating more and more capabilities within electronic devices, costs are reduced and reliability increased. Touch screens are frequently used in combination with conventional soft displays such as cathode ray tubes (CRTs), liquid crystal displays (LCDs), plasma displays and electroluminescent displays. The touch screens are manufactured as separate devices and mechanically mated to the viewing surfaces of the displays.
FIG. 1
shows a prior art touch screen
10
. The touch screen
10
includes a transparent substrate
12
. This substrate
12
is typically rigid, and is usually glass, although sometimes a flexible material, such as plastic, is used. Various additional layers of materials forming touch sensitive elements
14
of the touch screen
10
are formed on top of the substrate
12
. The touch sensitive elements
14
include transducers and circuitry that are necessary to detect a touch by an object, in a manner that can be used to compute the location of such a touch. A cable
16
is attached to the circuitry so that various signals may be brought onto or off of the touch screen
10
. The cable
16
is connected to an external controller
18
. The external controller
18
coordinates the application of various signals to the touch screen
10
, and performs calculations based on responses of the touch sensitive elements to touches, in order to extract the (X, Y) coordinates of the touch.
There are three commonly used touch screen technologies that utilize this basic structure: resistive, capacitive, and surface acoustic wave (SAW). For more information on these technologies, see “Weighing in on touch technology,” by Scott Smith, published in Control Solutions Magazine, May 2000.
There are three types of resistive touch screens, 4-wire, 5-wire, and 8-wire. The three types share similar structures.
FIG. 2
a
shows a top view of a resistive touch screen
10
.
FIG. 2
b
shows a side view of the resistive touch screen
10
. The touch sensitive elements
14
of the resistive touch screen
10
includes a lower circuit layer
20
; a flexible spacer layer
22
containing a matrix of spacer dots
24
; a flexible upper circuit layer
26
; and a flexible top protective layer
28
. All of these layers are transparent. The lower circuit layer
20
often comprises conductive materials deposited on the substrate
12
, forming a circuit pattern.
The main difference between 4-wire, 5-wire, and 8-wire touch screens is the circuit pattern in the lower circuit layer
20
and the upper circuit layer
26
, and the means for making resistance measurements. An external controller
18
is connected to the touch screen circuitry via cable
16
. Conductors in cable
16
are connected to the circuitry within the lower circuit layer
20
and the upper circuit layer
26
. The external controller
18
coordinates the application of voltages to the touch screen circuit elements. When a resistive touch screen is pressed, the pressing object, whether a finger, a stylus, or some other object, deforms the top protective layer
28
, the upper circuit layer
26
, and the spacer layer
22
, forming a conductive path at the point of the touch between the lower circuit layer
20
and the upper circuit layer
26
. A voltage is formed in proportion to the relative resistances in the circuit at the point of touch, and is measured by the external controller
18
connected to the other end of the cable
16
. The controller
18
then computes the (X, Y) coordinates of the point of touch. For more information on the operation of resistive touch screens, see “Touch Screen Controller Tips,” Application Bulletin AB-158, Burr-Brown, Inc. (Tucson, Ariz.), April 2000, pages 1-9.
FIG. 3
a
shows a top view of a capacitive sensing touch screen
10
.
FIG. 3
b
shows a side view of the capacitive sensing touch screen
10
. The touch sensitive elements
14
include a transparent metal oxide layer
30
formed on substrate
12
. Metal contacts
32
,
34
,
36
, and
38
are located on the metal oxide layer
30
at the comers of the touch screen
10
. These metal contacts are connected by circuitry
31
to conductors in cable
16
. An external controller
18
causes voltages to be applied to the metal contacts
32
,
34
,
36
, and
38
, creating a uniform electric field across the surface of the substrate
12
, propagated through the transparent metal oxide layer
30
. When a finger or other conductive object touches the touch screen, it capacitively couples with the screen causing a minute amount of current to flow to the point of contact, where the current flow from each comer contact is proportional to the distance from the comer to the point of contact. The controller
18
measures the current flow proportions and computes the (X, Y) coordinates of the point of touch. U.S. Pat. No. 5,650,597, issued Jul. 22, 1997 to Redmayne describes a variation on capacitive touch screen technology utilizing a technique called differential sensing.
FIG. 4
a
shows a top view of a prior art surface acoustic wave (SAW) touch screen
10
.
FIG. 4
b
shows a side view of a SAW touch screen
10
. The touch sensitive elements
14
include an arrangement of acoustic transducers
46
and sound wave reflectors
48
formed on the face of substrate
12
. The sound wave reflectors
48
are capable of reflecting high frequency sound waves that are transmitted along the substrate surface, and are placed in patterns conducive to proper wave reflection. Four acoustic transducers
46
are formed on the substrate
12
and are used to launch and sense sound waves on the substrate surface. A cable
16
is bonded to the substrate
12
, and contains conductors that connect the acoustic transducers
46
to an external controller
18
. This external controller
18
applies signals to the acoustic transducers
46
, causing high frequency sound waves to be emitted across the substrate
12
. When an object touches the touch screen, the sound wave field is disturbed. The transducers
46
detect this disturbance, and external controller
18
uses this information to calculate the (X, Y) coordinate of the touch.
FIG. 5
shows a typical prior art electroluminescent display such as an organic light emitting diode OLED flat panel display
49
of the type shown in U.S. Pat. No. 5,688,551, issued Nov. 18, 1997 to Littman et al. The OLED display includes substrate
50
that provides a mechanical support for the display device. The substrate
50
is typically glass, but other materials, such as plastic, may be used. Light-emitting elements
52
include conductors
54
, a hole injection layer
56
, an organic light emitter
58
, an electron transport layer
60
and a metal cathode layer
62
. When a voltage is applied by a voltage source
64
across the light emitting elements
52
, via cable
67
, light
66
is emitted through the substrate
50
, or through a transparent cathode layer
62
.
The OLED structure described in relation to
FIG. 5
is commonly known as a bottom-emitting structure, where light is emitted through the substrate
50
, conductors
54
, and hole injection layer
56
. An alternative OLED structure, known as a top-emitting structure, similar to that described by International Patent WO 00/17911, issued on Mar. 30, 2000 to Pichler, is shown in FIG.
6
. Here, light emitting elements
52
, including conductors
54
, a hole injection layer
56
, an organic light emitter
58
, an electron transport layer
60
and a metal cathode layer
62
, are formed on substrate
50
. A transparent cover sheet
51
is then placed above metal cathode layer
62
, and is sealed to the substrate
50
. In the top-emitting OLED structure, light is emitted by the organic light emitter
58
through the electron transport layer
60
, the metal cathode layer
62
, and the transparent cover sheet
51
Cropper Andre D.
Feldman Rodney
Kilmer Kathleen
Siwinski Michael J.
Anderson Andrew J.
Close Thomas H.
Eastman Kodak Company
Williams Joseph
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