GB2516439A

GB2516439A - Tactile keypad overlay for capacitive touch screen devices

Info

Publication number: GB2516439A
Application number: GB1313019.0A
Authority: GB
Inventors: Sanjay Karelia
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-07-22
Filing date: 2013-07-22
Publication date: 2015-01-28
Anticipated expiration: 2033-07-22
Also published as: GB2516439B; GB201313019D0

Abstract

A keypad overlay (4) for a capacitive touch screen (5) includes of a keypad overlay body with keys which are transparent to let the user see the characters displayed on virtual keypad. The overlay is arranged for aligning keypad keys with virtual keys, each key on keypad having top surface area and bottom surface area that are electrically interconnected, so that when top surface area is touched and applied pressure, bottom area comes in contact with the device screen. The electrical connection may be achieved by means of a small hole (11) whose surface area is coated with a transparent electrically conductive material (12) or by mean of making a key portion or the whole keypad with electrically conductive material. The keys maybe made of a shape and material that magnifies the view of characters displayed below.

Description

TACTILE KEYPAD OVERLAY FOR CAPACITIVE TOUCH SCREEN DEVICES

BACKGROUND OF THE INVENTION

Mobile telecommunication devices are becoming increasingly common and accessible. The variety and number of options are ever increasing. Gadgets like mobile phones and tablets are becoming house hold names and nowadays most of them are having touch screens as input medium.

A significant advancement in terms of touch technology has been the capacitive touch screen.

Devices with capacitive touch screens have a unique advantage of sensing slight touch of the user; usually Fingers and thumbs for inputting information in to devices through touch screen. With capacitive screens a virtual key is activated by the user's body capacitance and not by finger pressure.

One can perform various functions like Swipe the screen to change the page, Draw lines, or touch a specific area of screen representing a button or Key (Virtual Key) for the device to perform certain intended function.

One of such important function is to type texts, for example composing a message, email, notes or numbers. When the user initiates a function requiring text input, a virtual keypad appears on display screen. This virtual keypad is in form of several discrete areas on screen, each representing a virtual key corresponding to a specific character for example upper/lower case alphabet, Symbol, special character or a function like Shift or Ctr. When this virtual key is touched, corresponding character or function gets inputted into device and hence that character gets displayed on message field of screen or the device performs certain action.

When it comes to inputting several characters like typing a text message or an email, touch screen tends to become uncomfortable. Overall typing becomes a bit slow and number errors are relatively large when compared traditional physical key pressing action. This is mainly because there are more occasions when a nearby character other than intended gets activated. This problem gets even more prominent with smaller devices like mobile phones and Mini tabs.

One always feels the need of having a physical keypad while using a touch screen device, especially with capacitive screen where almost no or negligible pressure is required and hence no or least tactile feedback. The screen is flat and there is no physical distinction between the two keys.

The touch screen gadgets have notable feature of multiple virtual keypads. i.e. the same virtual key could represent various different characters like upper case alphabet, lower case alphabets, special characters, symbols etc at touch of a shift function button.

For users with shaky hands or with some kind of instability with fingers and hands like elderly people, this type of device may particularly become very difficult to use.

There could be a few keypad overlays already available, but almost all of them work with pressure sensing touch screen or require some form of wired/wireless electronic connection with the device, or are opaque requiring keycaps to be printed with characters on limited available space.

SUMMARY OFTHE INVENTION

The Proposed invention is a keypad overlay for use with capacitive display devices, comprising of a keypad overlay body with plurality of keys which are transparent to let the user see the characters displayed on virtual keypad, arrangement for aligning keypad keys with virtual keys, each key on keypad having top surface area and bottom surface area that are electrically interconnected, so that when top surface area is touched and applied pressure, bottom area comes in contact with the device screen, hence device registers an input and the user gets the feel of pressing a physical key.

BRIEF DESCRIPTION OF THE DRAWINGS

Refer to the drawings attached separately.

Fig 1 shows Tactile Keypad partially swung away from the device screen. This sketch shows a capacitive touch screen mobile device [1] which has no physical keypad. The device is housed in a protective case [2]. Tactile keypad [4] is attached to the protective case with a hinge arrangement [3] such that Tactile Keypad [4] could be swung on or away from device screen when required. The touch screen [5] is displayed with virtual keypad [5] on activation.

Device [1] could be any capacitive screen device like mobile phone, tablet or an instrument console basically having a keypad displayed on screen for inputting values by method of capacitance, usually via user fingers and thumbs or special stylus or any other source of capacitance.

Figure 2 shows Tactile Keypad [4] in place over the device screen and ready to be used.

When Tactile Keypad [4] is swung over the device screen, each projecting button on Tactile Keypad aligns with corresponding key on Virtual keypad.

Figure 3 shows partial Cross section of Tactile Keypad and the device screen.

Each Key has a top sensing area [9] and bottom sensing area [10] and a hole feature [11] coated with a transparent electrically conductive material [12], such that there is electrical continuity between top area [9] where key is touched and pressure is applied, and the bottom area [10] that comes in contact with touch screen [5].

The keys on keypad are made such that bottom sensing area [10] of the key is slightly away and not in contact with the device screen. This allows the user to position his fingers and thumbs on the desired key before pressing and inputting a value in to the device.

Figure 4 shows how a touch and application of pressure on tactile key result in to a continuous contact between Finger, lop sensing area, Hole, Bottom sensing area and the screen. This allows transmission of body capacitance to the screen sensing element and hence registering an input.

Figure 5 shows a preferable variant of key shape. The keys are made as continuous bumps and corresponding depressions on underside of each bump.

Figure 6 shows a preferable variant of tactile keypad as part of screen protection cover.

Figure 7 shows a preferable variant of tactile keypad for Tablets and Pads with capacitive screen. The Keypad is preferably Clipped or strapped or placed as a sleeve on the device.

DETAILED DESCRIPTION OF THE INVENTION

In Figure 1, the Tactile Keypad [4] is swung over virtual keypad area [6] of the device [1]. Tactile Keypad [4] is preferably attached with a suitable hinge mechanism [3] to part forming device back-cover or a protective case [2].

The tactile keypad has number of physical keys. Each physical key aligns over each virtual key of virtual keypad [6]. Tactile keypad [4] has as many or more number of keys as that on virtual keypad [6]. Each physical key is made in a way to get pressed on application of pressure on its top sensing area providing tactile feedback and activating the intended virtual key.

In Figure 3, each physical key has top sensing area [9], bottom sensing area [10] and a hole feature [11] to provide electrical continuity between top and bottom sensing areas. The top sensing area, bottom sensing area and surface of hole are selectively sprayed or coated with a continuous transparent conductive film [12]. 4 contact made by source of capacitance such as user's body; usually fingers and thumbs on top sensing area results in to transfer of capacitance to bottom sensing area. However this does not activate virtual key as there is no direct contact between human finger and capacitive screen surface [5]. When sufficient pressure is applied for the key to be depressed as shown in figure 4, the lower sensing area [10] comes in contact with capacitive touch screen [5] and thereby creating a continuous conductive path from finger [13 of Figure 4] to touch screen and hence inputting a value into device corresponding to value displayed on virtual key directly below the tactile key being pressed.

The keypad is made transparent enough to let the user see the character or characters displayed on virtual key, the conductive coat is transparent as well. This eliminates requirement of printing any information on keys and the same key can be used for inputting any number of different characters or values depending upon what is displayed on corresponding part of virtual key area. For example Upper case alphabets, Lower case alphabets, symbols, special characters, or multilingual characters etc., the possibilities are endless. It is not necessary to print on the keys. However if required some limited amount of information could be printed on keys.

The Tactile Keypad is made of suitable material like a variant of Rubber or plastic polymer of which the keypad overlays are generally made of.

The keypad is made such that it is transparent or semi-transparent enough to let the user see the characters displayed on corresponding virtual key area of screen through keypad.

For smaller devices like mobile phones preferably the keypad is part of protective case for it to securey remain in place and position accuratey on virtua keypad. For larger devices like Pads and tablets, the Tactile Keypad preferably is a loose piece of equipment to be aligned and placed over the screen when needed. Tactile Keypads made from materials like silicon will adhere to the screen.

In other arrangements for positioning preferably the keypad is clipped on the device or strapped to the device or put-on as a sleeve on the device.

As shown in Figure 6, the keypad preferably is built in part of screen protective cover. The cover portion is preferably transparent and not permitting any touch signas. This performs a dual function of protecting the screen as well as positioning the keypad correctly when required.

The keypad preferably is made of composite material where the whole of Key portion is made of electricaUy conductive rubber or plastic polymer that are transparent enough and the keypad frame is made of any other suitable non-conductive material. The frame may or may not be transparent.

The keypad is preferably made such that electrical continuity between top and bottom sensing areas of the key is provided by impregnation of some conductive material or in-moulded conductive wires/strands/mesh such that it is offering enough view of the characters displayed on virtual key.

Figure 5 shows a preferable variant of key shape. Instead of having clear valleys, this has continuous bumps.

The Keypad keys preferably have more than one interconnecting holes for better transmission of capacitance.

The Keys are preferably made of a material and a shape that provides magnified view of the characters on virtual key.

Claims

CLAIMS1. A keypad overlay for use with capacitive display devices, comprising of a keypad overlay body with plurality of keys which are transparent to let the user see the characters displayed on virtual keypad, arrangement for aligning keypad keys with virtual keys, each key on keypad having top surface area and bottom surface area that are electrically interconnected.
2. Keypad overlay of claim 1 where in there is a small hole across the key interconnecting the top and bottom sensing areas of the keys, The top and bottom areas including the surface area of the hole are coated with a thin continuous and transparent electrically conductive film or coat providing electrical continuity between the sensing areas of the key.
3. Keypad overlay of claim 2 where in there are more than one interconnecting holes.
4. The tactile keypad of claim 1 where in electrical continuity between top and bottom sensing areas of the key is provided by a making the key portion with an electrically conductive rubber, plastic polymer or other suitable material which is conductive by virtue of its properties.
5. The tactile keypad of claim 1 where in electrical continuity between top and bottom sensing areas of the key is provided by impregnation of some conductive material or in-moulded conductive wires/strands/mesh such that it is offering enough view of the characters displayed on virtual key.
6. The tactile keypad of claim 1 where in the whole of keypad is made of electrically conductive material including the frame and keys.
7. Keypad of claim 1 where in at least the key areas are transparent enough to let see the characters displayed on corresponding virtual key.
8. Keypad of claim 1 with limited information printed on it that do not block the view of the characters on virtual key.
9. Tactile keypad of claim 1 where in tactile keys are separated with a small gap or valley to distinguish each keys.
10. Tactile keypad of claim I where in tactile keys are made as continuous bumps and corresponding depressions on underside of keypad.
11. Tactile keypad of claim 1 where in tactile keys are made of a shape and material that magnifies the view of the characters displayed below the key.
12. Tactile keypad of Claim 1 where in instead of human body any other sources of capacitance is used to activate the key.
13. The tactile keypad of claim 1 where in an arrangement is provided for alignment of tactile keys of keypad with virtual keys on device screen, and an arrangement to bring the keypad over the screen for use and to take it away from screen when not in use.
14. The tactile keypad of claim 9 which is attached to or part of the back-cover or protective case of the device through a hinge mechanism.
15. The tactile keypad of claim 9 which is part of screen protection cover which in turn is hinged to back-cover or protection case.
16. The tactile keypad of claim 9 which is made of material like Silicon that adheres to the screen, to be manually overlaid and aligned by the user.
17. The tactile keypad of claim 9 that has a sliding mechanism for positioning and alignment of keypad.
18. The tactile keypad of claim 9 where in tactile keypad is clipped to the device 19. The tactile keypad of claim 9 where tactile keypad is like a sleeve to be put on the device.20. The tactile keypad of claim 9 where tactile keypad is strapped to the device.AMENDEMENTS TO CLAIMS HAVE BEEN FILED AS FOLLOWSCLAIMS1. A keypad overlay for use with a capacitive-screen display device, comprising a keypad overlay body with a plurality of keys which are transparent to let the user see through the overlay the characters displayed on the keys of a virtual keypad on the screen of the device, an arrangement for aligning keypad keys of the overlay with the virtual keys) each key of the overlay having a top surface area and a bottom surface area) a hole in each overlay key interconnecting the said top and bottom surface areas of the key, and a transparent electrically conductive coating on these areas and on the surface area of the hole thereby electrically interconnecting said areas.2. Keypad overlay of claim 1 wherein the said top and bottom areas and the surface area of the hole have been coated with a thin continuous and transparent electrically conductive film or coat) being said coating) providing electrical continuity between the sensing areas of the key.3. Keypad overlay of claim 1 or 2 wherein there are more than one of said interconnecting holes in a key.4. Keypad overlay of any preceding claim wherein the key areas are transparent enough to let the user see the characters displayed on corresponding virtual keys but other parts of the overlay are not so transparent.5. Keypad overlay of any preceding claim with limited information printed on it that does not block the view of the characters on the virtual keypad.6. Keypad overlay of any preceding claim wherein neighbouring overlay keys are separated with a small gap or valley to enable the user to distinguish between neighbouring keys in a tactile manner.0 7. Keypad overlay of any one of claims ito 6 wherein neighbouring keys are continuous and can be distinguished n a tactile manner by being formed as bumps in the overlay with corresponding depressions on the underside of the bumps.8. Keypad of any preceding claim wherein the keys are made of a shape and material that magnifies the view of the characters displayed below the keys.9. Keypad of any preceding claim adapted for any other source of capacitance instead of the human body to be used to activate the keys of the virtual keypad.10. Keypad of any preceding claim wherein an arrangement is provided for alignment of the keys of the overlay keypad with the virtual keypad keys, and to bring the keypad over the screen for use and to take it away from the screen when not in use.11. Keypad of any preceding claim which is attached to or part of the hack-cover or protective case of said device through a hinge mechanism.12. Keypad of any one of claims ito 10 which is part of a screen protection cover which in turn is hinged to a back-cover or protection case of said device.13. Keypad of any one of claims ito 10 which is made of material like Silicon that adheres to the screen) to be manually overlaid and aligned by the user.14. Keypad of any one of claims ito 10 that has a sliding mechanism for positioning and alignment of the overlay keypad.15. Keypad of any one of claims ito 10 wherein the overlay keypad is clipped to said device.S16. Keypad of any one of claims ito 10 wherein the overlay keypad is like a sleeve to be put on said device.17. Keypad of any one of claims ito 10 wherein the overlay keypad is strapped to said device.18. Keypad overlay as claimed in claim i and substantially according to any example hereinbefore described.
19. Keypad overlay as claimed in claim i and substantially according to any example hereinbefore described with reference to the accompanying drawings.
20. A combination of a keypad overlay as claimed in any preceding claim in combination with a capacitive display screen device with which the overlay is adapted to be used. r (4