Input Device

In accordance with an example embodiment of the present invention, an apparatus is disclosed with: a touch surface having one or more key tops configured to identify one or more keys to a user; a key sensing circuitry configured to detect a key press of any one or more of the key tops; a network of electromagnetic touch detectors configured to continually detect touching of the touch surface; and an elastic layer between the key sensing circuitry and the key tops configured to relay pressing forces from the key tops to the key sensing circuitry.

TECHNICAL FIELD

The present application generally relates to an input device.

BACKGROUND

Touchscreens have become very common as they enable very simple and intuitive pointing operations, for example. However, touchscreens have some disadvantages such as that for touching a given part of the touchscreen, the user has to partly obscure the touchscreen with her finger. The touching also tends to smear the surface of the touchscreen so that increased brightness may be needed with the associated cost at battery life. Moreover, actual keys are generally more convenient for typing as they usually provide a clear tactile response with a key depressed issuing a sudden decrease in the key force, click action, coinciding with reading of a key press.

Sometimes, touchscreens and keypads are combined by arranging a keypad near a touchscreen. Thus, best of both worlds can be combined, although the issues with touchscreens still remain.

SUMMARY

According to a first example aspect of the present invention, there is provided an apparatus comprising:

a touch surface comprising one or more key tops configured to identify one or more keys to a user;

a key sensing circuitry configured to detect a key press of any one or more of the key tops;

a network of electromagnetic touch detectors configured to continually detect touching of the touch surface; and

an elastic layer between the key sensing circuitry and the key tops configured to relay pressing forces from the key tops to the key sensing circuitry.

According to a second example aspect of the present invention, there is provided a device comprising a display; and the apparatus of the first example aspect.

According to a third example aspect of the present invention, there is provided a method comprising:

forming a touch surface comprising one or more key tops configured to identify one or more keys to a user;

forming a key sensing circuitry configured to detect a key press of any one or more of the key tops;

forming a network of electromagnetic touch detectors configured to continually detect touching of the touch surface; and

forming an elastic layer between the key sensing circuitry and the key tops configured to relay pressing forces from the key tops to the key sensing circuitry.

The network of electromagnetic detectors may be formed by selective activation plating.

The network of electromagnetic detectors may be formed by super energy beam induced deposition.

The network of electromagnetic detectors may be formed onto a separate layer. Alternatively, the network of electromagnetic detectors may be formed onto a rear surface of an exterior layer that forms the key tops and; or onto the elastic layer.

DETAILED DESCRIPTON OF THE DRAWINGS

An example embodiment of the present invention and its potential advantages are understood by referring toFIGS. 1 through 7of the drawings.

FIG. 1shows an apparatus100according to an example embodiment of the invention. The apparatus100of this example is a portable device such as a mobile telephone; navigation device; game console; electronic book; a laptop computer; and/or personal digital assistant. The apparatus100comprises a display110such as a liquid crystal display; an organic light emitting diode display; or an electric ink display. The display can be configured to display any graphics and text, with two soft key legends112and114shown near one edge of the display110for an example. Next to the display or adjacent to the display110a touch control surface120is provided for use e.g. as known from touch pads. Additionally, the touch control surface120can be used to implement one or more soft keys so that on touching a region of the touch control surface120next to a soft key legend112,114, a corresponding action is taken. The apparatus100further comprises one or more keys130e.g. in the form of a keypad or keyboard.

The keys130together form a touch surface on which a user can hover or slide her finger e.g. for controlling the apparatus100. In embodiments with the touch control surface120, the touch control surface120and the touch surface of the keys130can be used together as one large touch area through which user input may be read by touch detection while the keys130can still be used as normal keys.FIG. 2illustrates an example of some components with which a combined touch detection and key detection can be provided.FIG. 3shows the components ofFIG. 2when assembled. The keys130together form an exterior layer310behind which there is a sensing layer210carrying key sensing layer that has a network of electromagnetic detectors212e.g. as printed antennas. The exterior layer310is in an example embodiment 0.5 mm to 1.5 mm or more thick. The sensing layer210is e.g. 0.1 to 1 mm thick. In one example embodiment, the sensing layer210is 0.15 mm to 0.3 mm thick. Further behind the sensing layer210there is shown a rubber layer (e.g. of natural or synthetic rubber or thermoplastic polyurethane)220that is configured to act as an elastic layer that relies on key presses to underlying key sensing circuitry (seeFIG. 4for domes420andFIG. 7for an example of a key sensing circuitry).

FIG. 4illustrates a section view of some parts of an apparatus that comprises a combined touch detection and key press detection. The sensing layer210is located immediately behind the keys130(or touch surface or touch layer) so that a finger tip or stylus touching the touch surface or top of the keys130can be detected e.g. with capacitive sensing. On the other hand, if a key130is pressed, the key press is relayed through the sensing layer210and the rubber layer220to the key sensing circuitry (e.g. key dome420). With the rubber layer220in between, the tactile response can be made more convenient and clicking sound be somewhat reduced. Moreover, the rubber layer220provides a degree of softness and voids at borders between keys so that the touch sensing layer210can flex with larger radius than if being placed directly between the keys130and the key domes420. Moreover, the rubber layer220can be configured to reduce mechanical shocks and thus extend lifetime of the key sensing circuitry.

The key tops130on the touch surface are configured in one example embodiment to identify one or more keys to a user. The key tops can be formed of a single sheet of plastic for example or discrete parts. If formed of a single sheet, then the different keys can be identified by a suitable pattern, for example. With discrete parts, the boundaries or borders of the key tops form the identification.

The key sensing circuitry is in one example embodiment a matrix of signal lines that cross at each dome and the key press is determined by detecting which signal lines become connected together on pressing a key. In another example embodiment, each key has an independent connection that enables simultaneous detection of pressing of two or more keys. An example of a key detection circuitry will be described in the following with reference toFIG. 7. In an alternative embodiment the key sensing circuitry can comprise two or more conductive tracks that may be shorted together to indicate the presence of a physical touch. In yet another example embodiment, the key sensing circuitry comprises a surface acoustic wave sensor. Various known techniques can be used for the key sensing and thus this part is not explained any further.

The operation of touch sensors as such is known and thus needs no detailed description. However,FIG. 2illustrates the electromagnetic detectors212around each key. This arrangement is provided to illustrate one example embodiment in which connectors are deliberately formed between contacting portions of the key tops and the electromagnetic detectors212. With the rubber layer220having protrusions aligned with the keys, there are gaps between the protrusions where the electromagnetic detectors212are not likely to be abraded when the keys are being pressed. The electromagnetic detectors212are yet so aligned and monitored that a touch at any key or region between any keys is detected by an assigned touch detector (not shown). In one example embodiment, the electromagnetic detectors212are arranged in a grid that is not necessarily aligned with the key tops.

In one example embodiment, selective activation plating is used for forming the electromagnetic detectors212. In broad terms, energy beams can be used to sublimate selectively plastics areas so as to expose particular nano-size particles encapsulated in a polymer matrix of the plastics. This can efficiently promote electroless plating so that only the selected area can be plated. For instance, super energy beam induced deposition (SBID) is used in forming the electromagnetic detectors212to the touch sensing layer210as shown inFIG. 5. In step510, sheet material (e.g. a plastic film) is first printed with a suitable SBID ink. Following the printing, laser sublimation520is selectively applied in desired areas. Then, electroless plating530by Cu,Ni—Cu is performed, an electroless plating540by Ni is performed and an electroless plating550by Cu or Au is performed. The formed circuitry is then bonded560to the touch sensing layer210. The bonding is made in one example embodiment with a bond flexible printed circuit (FPC) for connecting to a printed wire board (PWB) e.g. using thermo-sensitive adhesive In the SBID, a pattern can be formed on substrate that comprises e.g. polycarbonate (PC) and/or polycarbonate-acrylonitrile butadiene styrene (PC-ABS) with active particles. Sublimation part of the SBID can be made by laser etching.

FIG. 6shows a section of some components of an apparatus according to an example embodiment, such as the apparatus100ofFIG. 1.FIG. 6also exemplifies an embodiment in which the touch sensing layer210extends beyond the touch surface formed by the keys130to sense touching at the touch control surface120. In other words, the touch surface has a first region and a second region non-overlapping the first region; and the key tops are solely comprised by the first region.

FIG. 6also shows another layer such as a plastic film305covering the touch sensing layer210at the touch control surface120. In another example embodiment (not shown), there is no separate layer covering the touch sensing layer210at the touch control surface. Instead, the touch sensing layer210can be uncovered at this region. For protection against scratching, a lacquer treatment or painting is applied at this region in one example embodiment.

FIG. 6also shows a sectional view of an exterior layer310comprising a first side configured to form the touch surface. The exterior layer310is e.g. formed of a single layer e.g. of plastic material. The plastic material can be flexible such as polyethylene (high density), polypropylene, polyurethane, synthetic rubber, nylon, ethylene vinyl acetate, polyvinyl chloride, and/or thermoplastic elastomer. Alternatively, the exterior layer310can be formed of rigid material such as non-flexible plastic material or metal with flexible connections allowing a degree of deforming in the exterior layer. In an example embodiment, the touch sensing layer210is resiliently biased with the elastic layer against the exterior layer310such that on pressing one of the one or more key tops, the movement of the touch sensing layer210is greater with respect to the pressed key top. When the touch sensing layer210can move over a greater area than the key top above, the touch sensing layer210can be made of less flexible materials and/or tensions incurred in the touch sensing layer210be reduced.

WhileFIG. 6shows separate layers for the key press detection, touch detection and for the key tops as well as the rubber layer220, some example embodiments combine layers together. For instance, in one example embodiment, the electromagnetic detectors are formed on rear side of the exterior layer310that forms the key tops. In another example embodiment, the electromagnetic detectors are instead formed onto the rubber layer220, on a side that is nearer to the exterior layer310.

FIG. 7shows a key detection circuitry700according to an example embodiment. The key detection circuitry is configured to form varying resistance between a voltage supply node720and ground using suitably connected and dimensioned resistors710,720. When a key is pressed, a corresponding dome420connects lines crossing at the dome thus forming paths of individual resistance to the ground so that the voltage at the voltage supply indicates the key that is being pressed. With suitable connection, two or more simultaneously pressed keys can also be detected. As a detector, the key detection circuitry700comprises an analogue to digital converter740.

Without in any way limiting the scope, interpretation, or application of the claims appearing below, a technical effect of one or more of the example embodiments disclosed herein is that touch detection can be combined with key press detection with simple and reliable equipment. Another technical effect of one or more of the example embodiments disclosed herein is that the equipment for combined touch and key press detection can be made very thin. Another technical effect of one or more of the example embodiments disclosed herein is that electromagnetic touch detectors can be located immediately behind the key tops. This can further enhance reliability of the touch detection. Yet another technical effect of one or more of the example embodiments disclosed herein is that the locating of the electromagnetic touch detectors immediately behind the key tops can enable lowering power of the electromagnetic touch detectors and thus reduce internal interference on other components and power consumption. The reducing internal interference can further reduce need for internal shielding. In battery operated devices, reduction of power consumption can enable extending battery life or reducing battery size.

If desired, the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore, if desired, one or more of the before-described functions may be optional or may be combined.

It is also noted herein that while the foregoing describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.