Compact cursor controller structure for use with laptop, notebook and hand-held computers and keyboards

A compact cursor controller includes a housing having an opening through the top thereof. A controller structure is substantially disposed within the housing and has a puck extending through the opening and a first brush within the housing and a second brush within the housing. A printed circuit board is disposed within the housing and coupled to the first brush and the second brush and configured to generate a first sensor signal in response to movement of the first brush on a first conductive strip and to generate a second sensor signal in response movement of the second brush on a second conductive strip oriented perpendicular to the first conductive strip. A processor is coupled to the first conductive strip and the second conductive strip and configured to receive the first sensor signal and the second sensor signal to determine a position of the puck. The processor then sends a puck position signal to a computer. Advantages of the invention include compact size and a high degree of accurate cursor control. Moreover, the invention provides good ergonomics that reduces fatigue.

FIELD 
The present invention relates to a compact cursor controller structure for 
use with laptop, notebook and hand-held computers and keyboards. In 
particular, the invention can be used with small computers to provide a 
cursor controller having improved comfort of use and accuracy of cursor 
control over existing joystick, j-key, track-ball, touch pad, and other 
conventional technologies. 
BACKGROUND 
Known types of cursor controllers for laptop computers include a j-key, 
which is a small joystick adjacent to the j key on the computer keyboard, 
a track-ball and a touch pad that responds to a user's finger impressions. 
These devices have an advantage for laptop computers over a conventional 
mouse because these devices are easily constructed into the laptop 
computer keyboard area and do not require the relatively large area used 
by a mouse and mouse pad. However, these devices do not provide the same 
high degree of cursor control on the display that can be obtained with a 
mouse. For example, a mouse is preferred for drafting figures where 
position of the cursor must be accurately controlled. Thus, a limitation 
of known small cursor controllers is that they do not provide sufficient 
control over the accuracy of the cursor on the computer display. 
A goal of the invention is to overcome the identified limitations and to 
provide a compact cursor controller that combines both small size and a 
high degree of accurate cursor control. 
SUMMARY 
The invention overcomes the identified problems and provides a compact 
cursor controller with fast, comfortable and accurate cursor control. An 
exemplary embodiment of a compact cursor controller includes a housing 
having an opening through the top thereof. A controller structure is 
substantially disposed within the housing and has a puck extending through 
the opening and a first brush within the housing and a second brush within 
the housing. A printed circuit board is disposed within the housing and 
coupled to the first brush and the second brush and configured to generate 
a first sensor signal in response to movement of the first brush on a 
first conductive strip and to generate a second sensor signal in response 
movement of the second brush on a second conductive strip oriented 
perpendicular to the first conductive strip. A processor is coupled to the 
first conductive strip and the second conductive strip and configured to 
receive the first sensor signal and the second sensor signal to determine 
a position of the puck. The processor then sends a puck position signal to 
a computer. 
In one embodiment, the housing is less than approximately 6.5 cm wide, 4.88 
cm deep and 0.85 cm high, and the opening is approximately 2.27 cm by 1.87 
cm. This small design allows the puck to be manipulated by the user by 
moving his fingers and without moving the wrist. Since the puck is small 
and has low mass, the fingers can easily manipulate the puck. This 
configuration is very ergonomic and reduces fatigue and repetitive motion 
problems with the user. 
Advantages of the invention include compact size and a high degree of 
accurate cursor control. Moreover, the invention provides good ergonomics 
that reduces fatigue.

DETAILED DESCRIPTION 
Exemplary embodiments are described with reference to specific 
configurations and dimensions. Those skilled in the art will appreciate 
that various changes and modifications can be made while remaining within 
the scope of the claims. 
FIG. 1 depicts a compact cursor controller 10 according to an embodiment of 
the invention. Controller 10 includes a housing 12 having an opening 14 
through the top. A puck 16 extends up through the opening 14 and is 
intended for manipulation by a user. The controller 12 is coupled via 
cable 18 to a computer 20. The computer is also coupled to a keyboard 22 
and display 24. Display 24 has a display cursor 26 that serves to 
highlight a position on the display. The invention provides that 
manipulation of the puck 16 by the user causes the cursor 26 to be 
correspondingly manipulated by the computer 20 on the display 24. Such 
function is known in the art and is described, for example, in U.S. Pat. 
No. 4,935,728, incorporated herein by reference. 
The invention focuses on the physical structure of the compact cursor 
controller 10. As shown in FIG. 1, the invention can be configured as a 
stand alone unit as a replacement for a mouse and communicate with the 
computer over cable 18. Alternatively, the invention can be incorporated 
into a keyboard for use with a desktop computer. FIG. 2 depicts the 
compact cursor controller 10 installed in a notebook computer. The housing 
12 is designed to be compact enough for production in laptop computers, 
notebook computers, hand-held computers and other types of computers. The 
compact cursor controller can be positioned adjacent to the keyboard, as 
shown, or can alternately be placed in any region on the keyboard surface 
such as above the keyboard or the right or left of the keyboard, or can 
alternately be placed on a region that extends from or pops-out from the 
keyboard area. If the invention is incorporated into a laptop, notebook or 
hand-held computer, the invention can use a connector that couples 
directly to an internal printed circuit board, such as the motherboard, 
eliminating the need for cable 18. 
FIGS. 3 and 4 depict an exploded view of a controller structure according 
to an embodiment of the invention. The controller structure is intended to 
fit substantially within housing 12. Puck 16 includes a protrusion 16a 
that connects to a plate 32 via opening 33 coupled to a select switch 34. 
Plate 32 is a moveable plate that includes a first recess 32a and a second 
recess 32b. Recesses 32a and 32b have peripheral protrusions that support 
plate 32 above guide 35. Guide 35 serves to maintain an orientation for 
plate 32 so that the recesses 32a and 32b smoothly move in their 
respective directions as plate 32 is moved by the puck 16. Guide 35 also 
serves as a holder for the wires to select switch 34. Guide 35 is in 
contact with to plate 36 having slots 36a and 36b. A first brush 42 is 
disposed within holder 46 that has a protrusion 46a designed to reside in 
recess 32a. A second brush 44 is disposed within holder 48 that has a 
protrusion 48a designed to reside in recess 32b. In this manner, when the 
puck 16 is moved by the user, the movement translates to plate 32 
(recesses 32a and 32b) that in turn moves holders 46 and 48 containing 
brushes 42 and 44. Note that the recesses 32a and 32b are positioned 
perpendicular to one another and that the slots 36a and 36b are 
perpendicular to one another but normal to the recesses 32a and 32b. This 
is because the holders 46 and 48 are designed to move freely in recesses 
32a and 32b within the bounds allowed by slots 36a and 36b. The result is 
that the brushes become uniquely positioned for each unique puck position. 
A printed circuit board 50 is positioned below the brushes 42 and 44 and 
attached to the plate 36. The printed circuit board includes features that 
can identify the positions of the brushes 42 and 44, as explained below. 
The invention is designed to be small and compact. As such, in one 
embodiment, the dimensions for the housing are in the range of 
approximately 6.5 cm wide, 4.88 cm deep and 0.85 cm high, and the opening 
is approximately 2.27 cm by 1.87 cm. In another embodiment, the dimensions 
for the housing are in the range of approximately 7 cm wide, 5 cm deep and 
0.5 cm high, and the opening is approximately 2.25 cm by 2 cm. 
FIGS. 5 and 6 depict an internal view of brushes, a printed circuit board 
and a processor according to an embodiment of the invention. A printed 
circuit board 50 (FIG. 3) attaches to the bottom of plate 36. The first 
brush 42 has three parts 42a-42c and the second brush 44 has three parts 
44a-44c. The printed circuit board 50 includes a first conductive strip 52 
and a second conductive strip 54 oriented perpendicular to the first 
conductive strip. These strips 52 and 54 are etched printed circuit 
patterns or silk-screened conductive patterns. The first strip 52 includes 
a first sub-strip 52a for ground, a second sub-strip 52b having a 
plurality of fingers laid on the printed circuit board and a third 
sub-strip 52c having a having a plurality of fingers laid on the printed 
circuit board staggered in position with the second sub-strip 52b. The 
sub-strips 52a-52c contact respective parts of the first brush 42a-42c. 
The second conductive strip 54 includes a first sub-strip 54a for ground, 
a second sub-strip 54b having a plurality of fingers laid on the printed 
circuit board and a third sub-strip 54c having a having a plurality of 
fingers laid on the printed circuit board staggered in position with the 
second sub-strip 54b. The sub-strips 54a-54c contact respective parts of 
the second brush 44a-44c. 
The first strip 52 generates a first sensor signal in response to movement 
of the first brush 42 on the first strip. The first sensor signal on 
strips 52b and 52c is pulled-up through a pull-up resistor. The first 
sensor signal is generated when the brush parts 42a-42c complete a circuit 
from the ground sub-strip 52a to the sub-strips 52b and 52c, pulling down 
the signals on strips 52b and 52c to ground. In particular, the sub-strip 
52b generates a sub-signal in response to movement of the part 42b and the 
sub-strip 52c generates a sub-signal in response to movement of the part 
42c. The second strip 54 generates a second sensor signal in response to 
movement of the second brush 44 on the second strip. The second sensor 
signal on strips 52b and 52c is pulled-up through a pull-up resistor. The 
second sensor signal is generated when the brush parts 44a-44c complete a 
circuit from the ground sub-strip 54a to the sub-strips 54b and 54c, 
pulling down the signals on strips 54b and 54c. In particular, the 
sub-strip 54b generates a sub-signal in response to movement of the part 
44b and the sub-strip 54c generates a sub-signal in response to movement 
of the part 44c. 
A processor 60 is coupled to the first conductive strip 52 the second 
conductive strip 54 and is configured to receive the first sensor signal 
and the second sensor signal to determine a position of the puck 16. In 
one embodiment, the processor is configured to receive the first 
sub-signal from the sub-strip 52b and the second sub-signal from the 
sub-strip 52c and to determine a direction of movement of the first brush 
42 on the first conductive strip 52. This is performed by comparing a 
phase of the first sub-signal and the second sub-signal. If the phase 
comparison is positive, the brush 42 is being moved on the strip 52 from 
left to right, and if the phase comparison is negative, the brush 42 is 
being moved on the strip from right to left. The processor processes the 
signals from strip 54 in the same way to determine position and motion. 
Referring to FIG. 6, the printed circuit board conductive strips and the 
staggered positions of the fingers are described. The fingers are made of 
1/4 or 1/8 oz. copper and the resolution of the traces can be brought down 
to 4 mil (0.004 inch) fingers and gaps. Since the two sub-strips are 
staggered in position as shown in FIG. 6, this provides approximately 500 
distinct graduations per inch. Unique data is generated by the strips and 
will be received by the processor 60 based on the brush position. For 
example, if the brush is in position A the sub-signals are 01, if the 
brush is in position B the sub-signals are 00, if the brush is in position 
C the sub-signals are 10, and if the brush is in position D the 
sub-signals are 11. This technique provides a high degree of mechanical 
precision (e.g resolution to 0.002 inch) at very low cost. Moreover, the 
pressure with which the brushes impress on the conductive strips is 
controlled by the construction and dimensions of the brushes and the 
cantilever spring constant. 
Once the processor 60 determines the position of the puck, by determining 
the position of the brushes 42 and 44 on strips 52 and 54, the processor 
informs the computer of the position and the cursor 26 on the display is 
adjusted by the computer accordingly. Also, the processor can determine 
movement direction of the brushes on the conductive strips by comparing 
the data sequence to a known directional data sequence. For example, a 
sequence of 01, 00, 10 and 11 means that the brushes are traveling from 
left to right in FIG. 6. Likewise, a sequence of 11, 10, 00 and 01 means 
that the brushes are traveling from right to left in FIG. 6. 
The processor 60 can further communicate with other components 62a-62i on 
the printed circuit board. These components can include switches for 
buttons that are positioned in the housing or on adjacent locations in 
order to inform the computer that the cursor movement should be tracked. 
Also, the processor can inform the computer that the identified position 
is to be selected for a function such as a hyper-link. These functions are 
well known in the art. 
Advantages of the invention include compact size and a high degree of 
accurate cursor control. 
Having disclosed exemplary embodiments and the best mode, modifications and 
variations may be made to the disclosed embodiments while remaining within 
the scope of the invention as defined by the following claims.