# Patent

## Title
System and methods for raised touch screens

## Abstract

A touch sensitive display assembly includes a touch screen and a button array. The touch screen is configured to display one or more input keys. The button array includes one or more buttons corresponding to the one or more input keys. The button array is formed by a substrate attached to a button membrane thereby creating a set of button cavities corresponding to the input keys. The button cavities are configured to be inflated and deflated by a pump coupled to a fluid reservoir. The cavities can be inflated/deflated together, in subsets, and/or individually. In some embodiments, the button array is sandwiched between a touch sensing layer and a display of the touch screen. In other embodiments, the button array can be located either above or below the touch screen.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 14/014,014, filed on 29 Aug. 2013, which is a continuation of U.S. patent application Ser. No. 11/969,848, filed on 4 Jan. 2008 and issued as U.S. Pat. No. 8,547,339 on 1 Oct. 2013, all of which are incorporated in their entireties by this reference.


BACKGROUND OF THE INVENTION
This invention relates generally to touch sensitive displays. More particularly, this invention relates to cost effective systems and methods for selectively raising portions of touch sensitive displays.
Touch sensitive displays, e.g., touch screens, are very useful in applications where a user can input commands and data directly on a display. Common applications for touch screens include consumer products such as cellular telephones and user interfaces for industrial process control. Depending on their specific applications, these touch sensitive displays are commonly used in devices ranging from small handheld PDAs to large pieces of industrial equipment.
While it is convenient to be able to input and output data to and from the user on the same display, unlike a dedicated input device such as a keypad with discrete well-defined keys, most touch sensitive displays are generally flat. As a result, touch sensitive screens do not provide any tactile guidance for control “button(s)”. Instead, touch sensitive displays rely on visual guidance for user input.
Hence a serious drawback of touch sensitive displays is its inherent difficulty to input data accurately because adjacent buttons are not distinguishable by feel. Wrongly entered key strokes are common and the user is forced to keep his or her eyes on the display. The lack of tactile guidance is especially critical in industrial settings where potentially dangerous machines and parts are in constant motion such as an automobile assembly line, and also when operating the controls of a moving vehicle such as making a cellular telephone call while driving.
It is therefore apparent that an urgent need exists for an improved touch sensitive display which provides tactile guidance to the user that is easy to manufacture, easy to retrofit, shock resistant, impact resistant, remains compact and portable, cost effective, and durable.
SUMMARY OF THE INVENTION
To achieve the foregoing and in accordance with the present invention, systems and methods for tactile guidance in touch sensitive screens are provided. Such touch screens can be operated very effectively and more safely without substantially increasing cost.
In one embodiment of the invention, a touch sensitive display assembly includes a touch screen and a button array. The touch screen is configured to display one or more input keys. The button array includes one or more buttons corresponding to the one or more input keys. The button array is formed by a substrate attached to a button membrane thereby creating a set of button cavities corresponding to the input keys.
The button cavities are configured to be inflated and deflated by a pump coupled to a fluid reservoir. The cavities can be inflated/deflated together, in subsets, and/or individually. In some embodiments, the button array is sandwiched between a touch sensing layer and a display of the touch screen. In other embodiments, the button array can be located either above or below the touch screen.
These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.



BRIEF DESCRIPTION OF THE DRAWINGS
In order that the present invention may be more clearly ascertained, one embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:
FIGS. 1A and 1B are cross-sectional views illustrating the operation of a button array in accordance with the present invention;
FIG. 2 is a cross-sectional view of one embodiment of the present invention;
FIGS. 3A, 3B and 4 are cross-sectional views of alternate embodiments of the present invention;
FIGS. 5 and 6 are top views showing a button array and an exemplary touch screen which can be combined to form an exemplary input and output (I/O) user interface suitable for telephone-based communication applications;
FIG. 7 is a block diagram illustrating one exemplary implementation of a device incorporating the touch sensitive user interface of the button array in accordance with the present invention; and
FIG. 8 is a flowchart illustrating the operation of touch screen assemblies of the present invention, including the embodiments shown in FIGS. 2, 3A, 3B and 4.



DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of the present invention may be better understood with reference to the drawings and discussions that follow.
FIGS. 1A and 1B are cross-sectional views illustrating the operation of a button array 100, useful in association with a touch sensitive display, in accordance with the present invention. Although only one button is shown, button array can include one or more buttons. In the following discussion and in the claims, touch sensitive display is used interchangeably with touch screen. Referring first to FIG. 1A, button array 100 includes a substrate 130 and a membrane 110 which are coupled to each other to form one or more enclosed cavities, e.g., enclosed cavity 120.
Substrate 130 can be made from a suitable optically transparent material including polymers or glass, for example, elastomers, silicon-based organic polymers such as poly-dimethylsiloxane (PDMS), thermoset plastics such as polymethyl methacrylate (PMMA), and photocurable solvent resistant elastomers such as perfluropolyethers. In some embodiments, substrate 130 is a single homogenous layer approximately 1 mm to 0.1 mm thick and can be manufactured using well-known techniques for micro-fluid arrays to create one or more cavities and/or micro channels. It is also possible to construct substrate 130 using multiple layers from the same material or from different suitable materials.
Membrane 110 can be made from a suitable optically transparent and elastic material including polymers or silicon-based elastomers such as poly-dimethylsiloxane (PDMS) or polyethylene terephthalate (PET). In some embodiments, membrane is a single homogeneous layer less than 1 mm thick (preferably 50 to 200 microns) and can be manufactured using techniques known to one skilled in the art. It is also possible to construct membrane 110 using multiple layers from the same material or from different suitable materials. Membrane 110 can be attached to substrate 130 using a suitable adhesive, ultra-sonic bonding, oxygen plasma surface treatment or any other suitable techniques known to one skilled in the art.
Enclosed cavity 120, formed between substrate 130 and membrane 110, is fluid tight and coupled via a fluid channel 140 to one or more fluid pumps (not shown in FIG. 1A). Note that the pump(s) can either be internal or external with respect to a touch screen assembly incorporating button array 100.
A suitable button fluid can be used to inflate exemplary cavity 120. To minimize optical distortion, the refractive index of the button fluid should be substantially similar to that of substrate 130 and also membrane 110. Depending on the application, suitable fluids include water and alcohols such isopropanol or methanol. It may also be possible to use an oil-based fluid such as Norland's index matching liquid (IML) 150 available from Norland Products of Cranbury, N.J.
Referring now to FIG. 1B, when button array 100 needs to be activated, i.e., raised or in other words inflated, fluid pressure inside cavity 120 is increased thereby causing membrane portion 110a to be raised. In this example which is suitable for a handheld device, cavity 120 has a cavity diameter of approximately 5 mm and membrane 110 is approximately 100 micron thick. Conversely, when button array 100 needs to be deactivated, fluid pressure inside cavity 120 is decreased thereby causing cavity 120 to deflate and membrane portion 110a to return to its original flat profile. It is contemplated that a button fluid pressure of approximately 0.2 psi and a button fluid displacement of about 0.03 ml should be sufficient to raise membrane (button) portion 110a by about 1 mm.
FIG. 2 shows a cross-sectional view of one embodiment of a touch sensitive display assembly comprising button array 100 of the present invention located on top of a touch display which includes a touch sensing layer 260 and a display screen 280. In this embodiment, button array 100 includes multiple cavities 220a, 220b, 220c and corresponding membrane portions 210a, 210b, 210c. Button array 100 is located just above touch sensing layer 260. Although FIG. 2 shows button array 100 in contact with touch sensing layer 260, it may be possible for a gap to exist between array 100 and sensing layer 260. The gap may optionally be filled with a suitable flexible solid or fluid material.
It is also possible for display screen 280 to include sensors that provide input capability thereby eliminating the need for sensing layer 260. For example, an LCD with embedded optical sensors both touch screen and scanner functions was announced in a 2007 press release by Sharp Electronics of Japan.
FIG. 3A is a cross-sectional view of another embodiment of a touch sensitive display assembly of the present invention wherein a touch sensing layer 360 and a display screen 380 of the touch sensitive display are separated. Button array 100 includes multiple cavities 320a, 320b, 320c and corresponding membrane portions 310a, 310b, 310c. In this embodiment, button array 100 is sandwiched between a flexible touch sensing layer 360 and display screen 380. As a result, raising membrane portions 310a, 310b, 310c results in the raising of sensing layer portions 360a, 360b, 360c, respectively.
FIG. 3B is a cross-sectional view of a variation of the touch sensitive display assembly of FIG. 3A wherein two or more cavities are inflated, a contiguous portion of touch sensing layer 360 is raised. In this embodiment, button array 100 is also sandwiched between touch sensing layer 360 and display screen 380. When cavities 320d, 320e are inflated, corresponding membrane portions 310d, 310e are raised, thereby causing the raising of sensing layer portions 360d, 360e. In addition, raising membrane portions 310d, 310e also results in the raising of touch sensing layer portion 360f located between sensing layer portions 360d, 360e. 
FIG. 4 is a cross-sectional view illustrating yet another embodiment of a touch sensitive display assembly wherein the entire touch screen is made from flexible material(s). Hence, the touch screen includes a flexible touch sensing layer 460 and a flexible display screen 480. Button array 100 includes one or more cavities 420a, 420b, 420c and corresponding membrane portions 410a, 410b, 410c. In this embodiment, button array 100 is located below display screen 480.
As discussed above, button array 100 and sensing layer 460 may be attached directly to each other or array 100 and layer 460 may be operatively coupled to each other via a suitable intermediate solid or fluid material.
FIGS. 5 and 6 are top views showing a button array 500 and an exemplary touch screen 600 which can be combined to form an exemplary input and output (I/O) user interface suitable for telecommunication applications. While the following description uses the 14-key telephone-based keypad of FIG. 5, the present invention is also applicable to many other non-telecommunication applications.
Button array 500 includes cavities 520a, 520b, 520c, 520d, 520e, 520f, 520g, 520h, 520k, 520m, 520n, 520p, 520q, 520r, while touch screen 600 is configured to able to display a set of corresponding input keys 620a, 620b, 620c, 620d, 620e, 620f, 620g, 620h, 620k, 620m, 620n, 620p, 620q, 620r. In this example, cavities 520a, 520b, 520c . . . 520r are overlaid on corresponding input keys 620a, 620b, 620c . . . 620r, using the exemplary techniques described above for the embodiments of FIGS. 2, 3A, 3B, 4.
As shown in FIG. 5, button array 500 is coupled to fluid pumps 572, 576. A fluid reservoir 574 is located between fluid pumps 572, 576. Suitable commercially available fluid pumps include pump #MDP2205 from ThinXXs Microtechnology AG of Zweibrucken, Germany and also pump #mp5 from Bartels Mikrotechnik GmbH of Dortmund, Germany.
Button array 500 is coupled to inflating fluid pump 572 and deflating fluid pump 576 via inlet fluid channel system 592 and outlet fluid channel system 596, respectively. In this example, fluid channel systems 592, 596 vary in width, i.e., wider in width nearer pumps 572, 576, in order to ensure fluid pressure and flow uniformity, in a manner similar to a human circulatory system.
Although the techniques discussed are applicable to many embodiments of the present invention, including the embodiments of FIGS. 2, 3A, 3B, 4, for this discussion, reference is made to the embodiment of FIG. 2. For ease of explanation, in the following discussion, all cavities 520a, 520b, 520c . . . 520r are inflated and deflated at the same time. Note that in some implementations, depending in the specific applications, cavities, e.g., cavities 520a, 520b, 520c . . . 520r, can be inflated and/or deflated individually, in subsets and/or as a complete set.
In this embodiment, inflating pump 572 is activated for a pre-determined period of time whenever cavities 520a, 520b, 520c . . . 520r need to be inflated. Note that deflating pump 576 remains “off” during inflation of cavities 520a, 520b, 520c . . . 520r. As a result, pump 572 is able to transfer fluid from fluid reservoir 574 to cavities 520a, 520b, 520c . . . 520r, until the required fluid pressure is accomplished. Inflating pump 572 is now deactivated, and both pumps 572, 576 are “off”. Fluid pressure is maintained in cavities 520a, 520b, 520c . . . 520r to keep them inflated.
Conversely, deflating pump 576 is activated for a pre-determined period of time whenever cavities 520a, 520b, 520c . . . 520r need to be deflated. Inflating pump 572 remains “off” during deflation of cavities 520a, 520b, 520c . . . 520r. As a result, deflating pump 576 is able to transfer fluid from cavities 520a, 520b, 520c . . . 520r back to fluid reservoir 574 to, until the required fluid pressure returns to the original value when deflating pump 576 is turned “off”.
Other pump configurations are also possible. For example, it is possible to replace pumps 572, 576 with a single bi-directional pump. It may also be possible to deflate cavities by opening value(s) to the fluid reservoir and let the fluid pressure decrease without the need for a separate deflating pump.
FIG. 7 is a block diagram illustrating one exemplary implementation of a device 700 incorporating a touch sensitive user interface in accordance with the present invention. Device 700 includes a microprocessor (CPU) 710, a button array controller 720, pump(s) 721, and button array 100. Depending on the implementation, device 700 may also include pressure sensor(s) 722 and valve(s) 723 coupled to pump(s) 720. Device 700 also includes a display controller 730 coupled to a display screen 280, and a touch screen controller 740 coupled to touch sensing layer 260.
FIG. 8 is a flowchart illustrating the operation of touch screen assemblies of the present invention, including the embodiments shown in FIGS. 2, 3A, 3B and 4. Referring to FIGS. 5 through 8, and using the embodiment of FIG. 2 as an example, in step 820, when display controller 730 causes display screen 280 to display a keypad, e.g., a telephone interface, button array controller 720 activates pump(s) 721 which causes button array 100, corresponding to the keys of keypad, to be inflated by increasing the pressure of the button fluid in cavities 220a, 220b, 220c (step 830).
In step 840, touch sensing layer 260 senses the location(s) of the user's depressions on one or more of corresponding membrane portions 210a, 210b, 210c of button array 100. Touch sensing layer 260 then outputs the coordinate(s) of the sensed location(s) to processor 710 via touch screen controller 740 (step 840).
If processor 710 recognizes that the sensed location(s) correspond to an “EXIT” type key, for example, a “CALL” key or an “END” key in this exemplary telecom implementation, then button array 200 is deflated (step 860). Otherwise, touch sensing layer 260 continues to sense location(s) of subsequent user depression(s) and outputting the sensed location(s) coordinates to touch screen controller 740 (repeat step 840, 850).
Many modifications and additions are contemplated within the spirit of the present invention. For example, it is possible to add distortion correction capability to display screens 280, 380, 480 for correcting any optical distortion that may be introduced by button array 100. It may also be possible to include a set of pressure sensors coupled to each of the corresponding cavities of button array 100 thereby eliminating the need for touch sensing layers 260, 360, 460.
While the present invention has been described with reference to particular embodiments, it will be understood that the embodiments are illustrative and that the inventive scope is not so limited. In addition, the various features of the present invention can be practiced alone or in combination. Alternative embodiments of the present invention will also become apparent to those having ordinary skill in the art to which the present invention pertains. Such alternate embodiments are considered to be encompassed within the spirit and scope of the present invention. Accordingly, the scope of the present invention is described by the appended claims and is supported by the foregoing description.

## Claims

1. A user interface system comprising:
a flexible touch sensing layer defining a deformable region, defining a peripheral region adjacent the deformable region, and outputting signals corresponding to touch inputs on the deformable region and the peripheral region;
a substrate coupled to the flexible touch sensing layer along a perimeter of the deformable region, cooperating with the deformable region to define a cavity, and defining a fluid channel fluidly coupled to the cavity;
a displacement device displacing fluid into the cavity via the fluid channel to transition the deformable region from a deflated setting into an inflated setting, the deformable region substantially flush with the peripheral region in the deflated setting and elevated above the peripheral region in the inflated setting; and
a processor detecting inputs on the flexible touch sensing layer proximal the deformable region in the deflated setting and in the inflated setting according to outputs of the flexible touch sensing layer.

2. The user interface system of claim 1, further comprising a flexible display interposed between the substrate and the flexible touch sensing layer, defining a first region attached to the substrate and to the peripheral region of the flexible touch sensing layer, and defining a second region adjacent the deformable region of the flexible touch sensing layer and disconnected from the substrate.

3. The user interface system of claim 1, further comprising an elastic membrane interposed between the substrate and the flexible touch sensing layer, defining a first region attached to the substrate and to the peripheral region of the flexible touch sensing layer, and defining a second region adjacent the deformable region of the flexible touch sensing layer and disconnected from the substrate.

4. The user interface system of claim 3, wherein the first region of the elastic member defines a perimeter about the cavity, and wherein a portion of the deformable region of the flexible touch sensing layer extends over the perimeter.

5. The user interface system of claim 3, wherein the substrate comprises a substantially transparent material, wherein the elastic membrane comprises a substantially transparent material, and further comprising a display coupled to the substrate opposite the elastic membrane.

6. The user interface system of claim 5, wherein the display renders an image of a digital keypad, a particular key of the digital keypad substantially aligned with the deformable region.

7. The user interface system of claim 6, wherein, in response to an input on the deformable region, the processor controls a function of a device coupled to the processor based on the particular key.

8. The user interface of claim 1, further comprising a reservoir containing fluid, wherein the substrate defines an inlet manifold and an exhaust manifold fluidly coupled to the fluid channel, and wherein the displacement device comprises an inflating pump and a deflating pump, the inflating pump displacing fluid from the reservoir into the cavity via the inlet manifold to transition the deformable region from the deflated setting into the inflated setting, the deflating pump displacing fluid from the cavity into the reservoir via the exhaust manifold to transition the deformable region from the inflated setting into the deflated setting.

9. The user interface of claim 8, further comprising a second processor activating the inflating pump for a pre-determined period of time to transition the deformable region from the deflated setting into the inflated setting, the second processor activating the deflating pump for a pre-determined period of time to transition the deformable region from the inflated setting into the deflated setting.

10. The user interface of claim 8, wherein the deflating pump comprises a valve arranged between the exhaust manifold and the reservoir.

11. The user interface of claim 1, wherein the displacement device increases fluid pressure within the cavity by approximately two-tenths of a pound-per-square-inch to transition the deformable region from the deflated setting into the inflated setting.

12. The user interface of claim 1, further comprising a pressure sensor coupled to the cavity, wherein the displacement controls fluid pressure within the cavity according to an output of the pressure sensor.

13. The user interface of claim 1, wherein the displacement device displaces approximately three-hundredths of one milliliter of fluid into the cavity to transition the deformable region from the deflated setting into the inflated setting.

14. The user interface of claim 1, wherein a surface of the flexible touch sensing layer at the deformable region and a surface of the flexible touch sensing layer at the peripheral region define a planar surface in the deflated setting, and wherein the surface of the flexible touch sensing layer at the deformable region is tactilely distinguishable from the surface of the flexible touch sensing layer at the peripheral region in the inflated setting.

15. The user interface of claim 14, wherein a surface of the flexible touch sensing layer at the deformable region is raised above a surface of the flexible touch sensing layer at the peripheral region by approximately one millimeter in the inflated setting.

16. A user interface system comprising:
a flexible display screen defining a deformable region, defining a peripheral region adjacent the deformable region, and outputting signals corresponding to touch inputs on the deformable region and the peripheral region;
a substrate coupled to the flexible display screen along a perimeter of the deformable region, cooperating with the deformable region to define a cavity, and defining a fluid channel fluidly coupled to the cavity;
a displacement device displacing fluid into the cavity via the fluid channel to transition the deformable region from a deflated setting into an inflated setting, the deformable region substantially flush with the peripheral region in the deflated setting and elevated above the peripheral region in the inflated setting; and
a display controller controlling the flexible display screen to render an image of a digital keypad, a key of the digital keypad substantially aligned with the deformable region in the inflated setting.

17. The user interface system of claim 16, further comprising a flexible touch sensor layer arranged over the flexible display screen opposite the substrate, the flexible touch sensor layer extending across the deformable region and the peripheral region.

18. The user interface system of claim 17, further comprising a processor detecting inputs proximal the deformable region in the deflated setting and in the inflated setting according to outputs of the flexible touch sensing layer.

19. The user interface system of claim 16,
wherein the flexible display screen defines a second deformable region,
wherein the substrate is coupled to the flexible display screen along a perimeter of the second deformable region, cooperates with the deformable region to define a second cavity, and defining a second fluid channel fluidly coupled to the cavity, and
wherein the displacement device displaces fluid into the second cavity via the second fluid channel to transition the second deformable region from the deflated setting into the inflated setting,
a second key of the digital keypad substantially aligned with the second deformable region in the inflated setting.

20. The user interface of claim 16, wherein a surface of the flexible display screen at the deformable region and a surface of the flexible display screen at the peripheral region define a planar surface in the deflated setting, and wherein the surface of the flexible display screen at the deformable region is tactilely distinguishable from the surface of the flexible display screen at the peripheral region in the inflated setting.