Electricity: circuit makers and breakers – Multiple circuit control – Pivoted contact
Reexamination Certificate
2002-02-07
2003-05-27
Scott, J. R. (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Pivoted contact
C200S0110TC, C345S163000
Reexamination Certificate
active
06570108
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a switch mechanism, and more specifically to a switch mechanism that is used in a pointing device to decide a rotational direction of a wheel installed on the pointing device.
2. Description of the Prior Art
In computer systems, the use of a windowing operating system to browse, edit or otherwise manipulate data is commonplace. Distinct graphical areas termed windows are displayed on the monitor that is connected to the computer system. Documents are displayed within the confines of the window for perusal by a user. If a document is too large, then only a portion of the document is displayed inside the window. If the user desires to see off-window portions of the document, then a mouse is used to manipulate a scroll bar located on a side of the window to scroll the window, and hence bring the hidden portions of the document into view. For example, if the user desires to browse in a downward direction within the window, the user clicks on a downward arrow sign of the scroll bar (by way of the mouse), and the document will move upward by a predetermined unit, usually by a line of text. Similarly, if the user wants to browse in an upward direction, the user uses the mouse to click on an upward arrow sign of the scroll bar, and the document is scrolled downward. The above is a familiar ground to general computer users, and so nothing more need be said about it.
FIG. 1
is a perspective view of a mechanical mouse
10
with a wheel
14
according to a prior art. The mechanical mouse
10
comprises a housing
12
. The wheel
14
is installed in the housing
14
, and is capable of rotating clockwise and counterclockwise so as to control a scroll bar on a side of a window to move the scroll bar upward and downward, enabling the user to scroll the window and thus conveniently browse a document. When the user is perusing a portion of a document, the user may rotate the wheel
14
of the mouse
10
clockwise to activate the scroll bar to scroll the document upward. Alternatively, the user may rotate the wheel
14
counterclockwise to activate the scroll bar to scroll the document downward. This is a familiar convenience that is well-know in the art.
FIG. 2
is a perspective view of an inner portion of the mechanical mouse
10
.
FIG. 3
is a top view of the inner portion of the mechanical mouse
10
. As shown in FIG.
2
and
FIG. 3
, the mechanical mouse
10
further comprises a substrate
16
installed inside the housing
12
, an support
20
installed on the substrate
16
having a notch
21
, a shaft
18
connected with the wheel
14
rotatably installed inside the notch
21
of the support
20
, a first light source
42
and a second light source
44
installed adjacent to the wheel
14
on two ends of the support
20
, and a first sensor
32
and a second sensor
34
installed on an opposite side of the wheel
14
at two ends of the upholder
20
. The wheel
14
has a rough surface
22
, and a plurality of narrow gaps
24
extend along a radial direction as measured from the center of the wheel
14
. The first light source
42
and the second light source
44
generate light
46
and light
48
, respectively. The first sensor
32
and the second sensor
34
are used to detect the light
46
and light
48
passing through the narrow gaps
24
respectively, and generate corresponding detecting signals.
FIG. 4
a
is a diagram of output signals of the two sensors
32
and
34
on a time axis when the wheel
14
of the prior art mechanical mouse
10
rotates clockwise.
FIG. 4
b
is a diagram of output signals of the two sensors
32
and
34
on a time axis when the wheel
14
of the prior art mechanical mouse
10
rotates counterclockwise.
FIG. 5
is a table contrasting output signals of the two sensors
32
and
34
with time when the wheel
14
of the mechanical mouse
10
rotates clockwise and counterclockwise as shown in
FIG. 4
1
and
FIG. 4
b.
When a user rotates the wheel
14
, the shaft
18
rotates inside the notch
21
of the support
20
. The narrow gaps
24
also rotate, following the wheel
14
. The number of narrow gaps
24
is carefully considered in the design of the wheel
14
, as are both the spacing between adjacent gaps
24
and the width of the gaps
24
. In a corresponding way, the positions of the first sensor
32
, the second sensor
34
, the first light source
42
and the second light source
44
are carefully selected. These carefully selected parameters enable differentiation of clockwise and counter-clockwise rotation of the wheel by waveform phase analysis of two optically detected signals. When the wheel
14
rotates clockwise and permits the light
46
generated by the first light source
42
to just pass through a narrow gap
24
to the first sensor
32
, the first sensor
32
will detect the light
46
and generate an output signal “1” (i.e., a high-potential signal). At the same time, the light
48
generated by the second light source
44
is blocked by the spacing between two narrow gaps
24
, and so the second sensor
34
is unable to detect the light
48
and generates an output signal “0” (i.e., a low-potential signal). Then, as the wheel
14
continues to rotate clockwise, the light
46
generated by the first light source
42
passes through the middle portion of the narrow gap
24
, continuing to arrive at the first sensor
32
. At the same time, the light
48
generated by the second light source
44
just passes through a narrow gap
24
and arrives at the second sensor
34
. Hence, the output signals generated by the first sensor
32
and the second sensor
34
are “1” and “1”, respectively. Continuing in this manner, it should be clear that the design of the narrow gaps
24
generates a phase discrepancy of 90 degrees between the output signal of the first sensor
32
and the second sensor
34
. As the wheel
14
continues to rotate clockwise, the output signals generated by the first sensor
32
and the second sensor
34
become “0” and “1”, respectively. As the wheel
14
rotates clockwise even more, the output signals generated by the first sensor
32
and the second sensor
34
change to “0” and “0”, respectively.
Although the wheel
14
is capable of vertical movement along the shaft
18
(i.e., that the wheel
14
is movable up-and-down while rotating inside the notch
21
of the support
20
), such movement does not affect the result of the output signals of the corresponding first sensor
32
and the second sensor
34
. That is, the phase difference between the output signals of the first sensor
32
and the second sensor
34
remains 90 degrees.
As shown in
FIG. 4
a
,
FIG. 4
b
and
FIG. 5
, when the wheel
14
rotates clockwise, if the output signal of the first sensor
32
is “0”, then the output signal of the second sensor
34
will be “1” inside a period t
1
. The output signal of the sensors
32
and
34
inside period t
1
may thus be though of as “01”. If the wheel
14
continues to rotate clockwise, the output signal of the sensors
32
and
34
inside period t
2
will be “00”. The output signal of the sensors
32
and
34
inside period t
3
is “10”. The output signal of the sensors
32
and
34
inside period t
4
is “11”. The output signals of the sensors
32
and
34
inside periods t
5
and t
6
are same as the output signals of the sensors
32
and
34
inside periods t
1
and t
2
, respectively. The output signals of the first sensor
32
and the second sensor
34
are thus periodic over four cycles. To determine whether the wheel
14
is rotating clockwise or counter-clockwise, one need only determine if the arrangement of the output signals of the sensors
32
and
34
changes from “01”, “00”, “10” to “11” in the proper sequence. For example, when the output signal of the sensors
32
and
34
changes from “00” to “10”, it is inferred that the wheel
14
is rotating clockwise. Similarly, when the wheel
14
rotates counterclockwise, the output signals of the first sensor
32
and the second sensor
34
also have four periods in
Hsu Winston
Primax Electronics Ltd.
Scott J. R.
LandOfFree
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