| United States Patent |
8,493,357 |
|
McCracken
|
July 23, 2013
|
Mechanical means for providing haptic feedback in connection with
capacitive sensing mechanisms
Abstract
Method and apparatus for providing haptic feedback in connection with a
capacitive sensing mechanism are described. In one embodiment, the
apparatus comprises a convex, non-metallic structure arranged so as to
maintain physical separation between an activator and the capacitive
sensing mechanism until sufficient force is applied by the activator. The
structure does not form a part of an electrical circuit comprising the
capacitive sensing mechanism.
| Inventors: |
McCracken; David (Aptos, CA) |
| Applicant: | | Name | City | State | Country | Type |
McCracken; David |
Aptos |
CA |
US | |
|
|---|
| Assignee: |
Integrated Device Technology, Inc
(San Jose,
CA)
|
| Family ID:
|
46753002
|
|---|
| Appl. No.:
|
13/041,173 |
|---|
| Filed:
|
March 4, 2011 |
|---|
| Current U.S. Class: |
345/174 ; 345/179 |
| Current International Class: |
G06F 3/045 (20060101) |
| Current CPC Class: |
G06F 3/045 (20130101) |
| Field of Search: |
345/173,174,179 178/18.01,19.03
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Cheng; Joe H
Attorney, Agent or Firm: Hayes and Boone LLP
Claims
What is claimed is:
1. Apparatus for providing haptic feedback in connection with a
capacitive sensing mechanism, the apparatus comprising a convex,
non-metallic structure arranged between
components of the capacitive sensing mechanism so as to maintain a
distance between an activation means and a component of the capacitive
sensing mechanism until sufficient force is applied by the activation
means, wherein the structure does not form a
part of an electrical circuit comprising the capacitive sensing
mechanism.
2. The apparatus of claim 1 wherein the structure is dome-shaped.
3. The apparatus of claim 1 wherein the structure comprises non-metalized plastic.
4. The apparatus of claim 1 wherein the structure comprises a tube.
5. The apparatus of claim 1 wherein the structure comprises a plastic tube having deformable material disposed therein.
6. The apparatus of claim 1 wherein the structure comprises a
plastic sheet including a plurality of bubbles and wherein the plastic
sheet is arranged such that each of the plastic bubbles overlies one of a
plurality of touch areas of the
capacitive sensing mechanism.
7. The apparatus of claim 1 wherein a switching threshold of the capacitive sensing mechanism is adjustable by a user.
8. Method for providing haptic feedback in connection with a
capacitive sensing mechanism disposed in an electronic device, the
method comprising arranging a non-metallic structure between components
of the capacitive sensing mechanism in such
manner as to maintain a distance between an activation means and a
component of the capacitive sensing mechanism until sufficient force is
applied with the activation means, wherein the structure does not form a
part of an electrical circuit comprising
the capacitive sensing mechanism.
9. The method of claim 8 wherein the structure is dome-shaped.
10. The method of claim 8 wherein the structure comprises non-metalized plastic.
11. The method of claim 8 wherein the structure comprises a tube.
12. The method of claim 8 wherein the structure comprises a tube having deformable material disposed therein.
13. The method of claim 8 wherein the structure comprises a
plastic sheet including a plurality of bubbles and wherein the plastic
sheet is arranged such that each of the plastic bubbles overlies one of a
plurality of touch areas of the
capacitive sensing mechanism.
14. An electronic device comprising a printed circuit board
("PCB") and an input device associated with the PCB, the input device
including a capacitive sensing mechanism and a haptic feedback structure
associated with the capacitive sensing
mechanism, the haptic feedback structure providing a physical barrier
between components of the capacitive sensing mechanism for preventing a
touch to be detected by the capacitive sensing mechanism until
sufficient force is applied with the activation
means, wherein the structure does not form a part of an electrical
circuit comprising the capacitive sensing mechanism.
15. The electronic device of claim 14 wherein the structure is dome-shaped.
16. The electronic device of claim 14 wherein the structure comprises non-metalized plastic.
17. The electronic device of claim 14 wherein the structure comprises a tube.
18. The electronic device of claim 14 wherein the structure
comprises a plastic tube having deformable material disposed therein.
19. The electronic device of claim 14 wherein the structure
comprises a plastic sheet including a plurality of bubbles and wherein
the plastic sheet is arranged such that each of the plastic bubbles
overlies one of a plurality of touch areas of
the capacitive sensing mechanism.
20. The electronic device of claim 14 wherein the activation means comprises a finger or a stylus.
Description
TECHNICAL FIELD
The present disclosure is related to capacitive sensing
mechanisms and, in particular, to mechanical means for providing haptic
feedback in connection with such mechanisms.
DISCUSSION OF RELATED ART
Capacitive sensing mechanisms, such as a capacitive
touchscreen, for example, enable implementation of electronic visual
displays that can detect the presence and location of contact within a
defined display area. Such mechanisms can sense
pressure applied by passive objects, such as a finger, for example. A
capacitive touch screen has two primary attributes that appeal to users.
First, it enables users to interact directly, rather than indirectly
using a mouse or touchpad, with what is
displayed. Additionally, it allows users to do so without the use of
any intermediate device, such as a stylus. Capacitive touch screen
displays play an important role in the implementation of digital devices
such as personal digital assistants
("PDAs") and mobile phones.
Touch buttons implemented using capacitive sensing mechanisms
include no moving parts and are inexpensive and reliable, but provide no
activation feedback and can be easily inadvertently activated. Some
handheld devices, such as the
Blackberry.RTM. device from Research in Motion, Inc., include
mechanical buttons on their front face, even though such buttons consume
more depth, are less reliable, and are more expensive than capacitive
touch buttons. The primary rationale for using
mechanical buttons, therefore, is that each button provides definitive
tactile, or haptic, feedback when pressed. Capacitive touch buttons
provide no such feedback.
Therefore, what is needed is an inexpensive and reliable means
for providing mechanical feedback in connection with activation of
capacitive touch buttons.
SUMMARY
One embodiment is an apparatus for providing haptic feedback in
connection with a capacitive sensing mechanism. The apparatus
comprises a convex, non-metallic structure arranged so as to maintain
physical separation between an activation means
and the capacitive sensing mechanism until sufficient force is applied
by with the activation means. The structure does not form a part of an
electrical circuit comprising the capacitive sensing mechanism.
Another embodiment is a method for providing haptic feedback in
connection with a capacitive sensing mechanism disposed in an
electronic device. The method comprises arranging an apparatus
comprising a convex, non-metallic structure in such
manner as to maintain physical separation between an activation means
and the capacitive sensing mechanism until sufficient force is applied
with the activation means. The structure does not form a part of an
electrical circuit comprising the capacitive
sensing mechanism.
Yet another embodiment is an electronic device comprising a
printed circuit board ("PCB") and an input device associated with the
PCB. The input device includes a capacitive sensing mechanism and a
haptic feedback structure associated with the
capacitive sensing mechanism. The haptic feedback structure provides a
physical barrier between an activation means and the capacitive sensing
mechanism for preventing a touch to be detected by the capacitive
sensing mechanism until sufficient force is
applied with the activation means. The structure does not form a part
of an electrical circuit comprising the capacitive sensing mechanism.
These and other embodiments will be described in further detail below with respect to the following figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a mechanical means for
providing haptic feedback in connection with a capacitive sensing
mechanism implemented as a combination navigation and activation device
in accordance with one embodiment.
FIG. 2 is a perspective view of a handheld device in which a
mechanical means for providing haptic feedback in connection with a
capacitive sensing mechanism is implemented as a squeeze switch in
accordance with one embodiment.
FIG. 3 is a cross-sectional view of the handheld device illustrated in FIG. 2 along a line 3-3.
FIG. 4 is a perspective view of a generic electronic device in
which a mechanical means for providing haptic feedback in connection
with a capacitive sensing mechanism is implemented as a completely
sealed switch matrix in accordance with one
embodiment.
FIG. 5 is cross-sectional view of the generic electronic device illustrated in FIG. 4 along a line 5-5.
FIG. 6 is a plan view of a front face of the generic electronic device illustrated in FIG. 4.
DETAILED DESCRIPTION
In the following description specific details are set forth
describing certain embodiments of the disclosure. It will be apparent,
however, to one skilled in the art that the present disclosure may be
practiced without some or all of these
specific details. The specific embodiments presented are meant to be
illustrative of the present disclosure, but not limiting. One skilled
in the art may realize other material that, although not specifically
described herein, is within the scope and
spirit of this disclosure. In the drawings, elements having the same
designation have the same or similar functions.
Some embodiments comprise a mechanical haptic feedback means
deployed in connection with a capacitive sensing mechanism, such as a
capacitive touch screen, for physically separating a finger or other
activating means, such as a stylus, from a
capacitive-sensing plate such that a "touch" is not registered until
sufficient force is applied to temporarily deform the haptic feedback
means, at which point the finger is close enough to register as a touch.
Importantly, in accordance with the
embodiments described herein, the haptic feedback means provides only
mechanical resistance and can therefore be fabricated simply and
inexpensively.
For example, in one embodiment, a mechanical haptic feedback
means comprises a flexible plastic sheet with one or more convex
bubbles, mechanically similar to dome-switch buttons. Unlike dome
switches, however, there is no circuitry plated on
the plastic, making it simpler and easier to produce and impervious to
the metal fatigue issues to which dome switches are so susceptible. The
plastic sheet is placed over a printed circuit board ("PCB") with touch
areas located under each bubble. Also
unlike dome-switch buttons, because nothing is plated on or attached to
the plastic, the plastic may be selected entirely for its mechanical
properties and cost. Bubbles can be designed with greater or lesser
height to increase feedback or reduce
profile, respectively. The switching threshold for the capacitive sense
circuitry is adjusted to prevent inadvertent activation by a resting
finger. In certain embodiments, especially those in which a user is in
continual physical contact with the
device in which the capacitive sensing mechanism is deployed, the
switching thresholds associated with the feedback means may be
user-adjustable.
FIG. 1 is a perspective view of a mechanical means for
providing haptic feedback in connection with a capacitive sensing
mechanism implemented as a combination navigation and activation device
100 in accordance with one embodiment. As shown in
FIG. 1, the device 100 may be implemented in connection with a mobile
phone device, such as the Blackberry.RTM. device, available from
Research in Motion Ltd. As shown in FIG. 1, in accordance with one
embodiment, a touchpad 102 comprises a navigation
zone and is disposed on a top surface of a proximal end of a flexible
PCB 104. A switch 106 is located directly below the touchpad on the
underside of the PCB 104. The PCB 104 is cantilevered from an
electrical/physical connector at a distal end
thereof. Applying pressure to the touchpad 102 in a direction indicated
by an arrow 108 forces the switch 106 toward a relatively immovable
object, such as a plate 110, activating the switch 106 when the switch
is moved to within a certain proximity to
the plate. Prior art embodiments have been implemented using metal or
plastic dome switches. As described above, plastic dome switches have
short lifetimes due to metallization fatigue. Metal dome switches are
difficult to mount, as they must be
physically captured without constraining their deformability. One
solution has been to fully constrain their perimeter (i.e. solder in
place) and to fabricate a dimpler bump on the immovable object, although
this may not be entirely satisfactory due to
wearing of the bump and compromises required in the metal spring design.
In the embodiment illustrated in FIG. 1 and described herein,
however, a spring mechanism 114 comprising a plastic dome is provided on
the underside of the touchpad 100 between the switch 106 and plate 110.
This arrangement functions as a
mechanical haptic feedback means. Because the spring mechanism 114 does
not form a direct part of the electrical switching circuit, the plastic
dome comprising the mechanism can be designed and mounted in manner
optimized for physical, rather than
electrical, properties. For example, to require greater force to be
applied before a touch is registered via the touch pad 102, the plastic
dome comprising the spring mechanism 114 may be constructed having a
greater height and of material having
greater resilience than if less force is to be required.
FIGS. 2 and 3 illustrate implementation of certain embodiments
of a mechanical haptic feedback means in connection with a squeeze
switch for a handheld device 200. As best shown in FIG. 3, a plastic
tube 202 is disposed along an outer perimeter
of the device 200. The tube 202 may be hollow or filled with foam or
other suitable sturdy but deformable material. The tube 202 may be
disposed in a depression in the side walls 204 of the device 200 and may
be retained therein by its own elasticity.
Inside the device 200, the walls 204 are sufficiently conductive to
serve as capacitive touch sensors. For example, the housing of the
device 200 itself may be metalized or may have sensors 206 comprising
metal strips or printed circuits attached to it. When the user picks up
the device 200 without squeezing it, their hand is not close enough to
the sensor(s) to register full (not proximity) touch. Squeezing brings
some parts of the hand close enough to the sensors 206 to register as
full touch. In
areas where the tube 202 is hollow, snap action is provided.
In one embodiment, the squeeze switch shown in FIGS. 2 and 3
may be designed to detect different amounts of pressure, or squeeze
force. For example, a user's merely picking up the device 200 without
squeezing it could trigger lighting of its
keyboard 210 only using proximity detection, while the user's squeezing
the device would result in the device itself being fully activated.
Additionally, push-button-like switching, squeeze switching, and/or
proximity detection functionality may be
combined in a single device 200 by simple changes in the fabrication,
composition, and/or filling of tube 202 itself. For example, the tube
202 could be left hollow in areas along the perimeter of the device 200
where push-button-type functionality is
desired, the hollow tube providing a snap action type of response to
being pressed. In areas where squeeze-type switching is desired, the
tube 202 may be filled with foam to damp snapping or may comprise a
different, less reactive, material in those
areas. Touch sensors, such as the sensors 206, disposed in the housing
of the device may be specifically coordinated with action areas along
the tube 202 or they may be generalized as a non-specific array of pads
along the perimeter, enabling action to
be redefined simply by changing the composition and/or filling of the
tube 202.
FIGS. 4, 5, and 6 illustrate implementation of certain
embodiments as a completely sealed capacitive switch matrix with tactile
feedback in a generic electronic device 400. As best shown in FIGS. 5
and 6, a PCB 401 having capacitive sensor pads
402 disposed on one side and components 404 disposed on the other is
disposed against an inside face of a first wall 406 of a non-conductive
enclosure 408. The wall 406 may be fabricated such that plastic domes
410 overlie each of the pads 402,
respectively, or a plastic overlay comprising the domes 410 may be
attached to the wall 406. In either case, depressing one of the domes
410 provides haptic feedback to the user. Additionally, the structure
of the dome 410 ensures that a requisite
amount of pressure is applied to a dome and its corresponding sensor pad
402 such that a touch of the pad is not registered inadvertently.
It will be recognized that the examples provided above are
exemplary only and are not intended to be limiting. One skilled in the
art may readily devise other forms of mechanical means for providing
haptic feedback in connection with capacitive
sensing mechanisms consistent with embodiments of the present disclosure
that are intended to be within the scope of this disclosure. As such,
the application is limited only by the following claims. Moreover, it
is understood that modifications,
changes and substitutions are intended in the foregoing disclosure and
in some instances some features of the embodiments will be employed
without a corresponding use of other features. Accordingly, it is
appropriate that the appended claims be
construed broadly and in a manner consistent with the scope of the
embodiments described herein.
Although the present disclosure has described embodiments
relating to specific environments, it is understood that the apparatus,
systems and methods described herein could applied to other
environments. While the preceding description shows
and describes one or more embodiments, it will be understood by those
skilled in the art that various changes in form and detail may be made
therein without departing from the spirit and scope of the present
disclosure. For example, various functions
illustrated in the methods or described elsewhere in the disclosure may
be combined to provide additional and/or alternate functions.
Therefore, the claims should be interpreted in a broad manner,
consistent with the present disclosure.
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