GB2382291A - Overlay for touch sensitive screen - Google Patents

Abstract

An overlay (<B>16</B>), constructed from flexible material to include buttons (<B>18</B> and <B>fig. 2</B>), is positioned to cover a touch sensitive screen (<B>14</B>). Upon pressing the keys of the overlay, a user applies pressure precisely on a specific part of the display. The display forms part of an electronic device (<B>10</B>), such as a PDA (Personal Digital Assistant) or palm top computer, and allows visually impaired operators to use the touch screen by providing indicators (e.g. braille symbols) on the overlay buttons. Users without visual impairment may prefer to use the device without the overlay.

Description

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OVERLAY FOR TOUCH-SENSITIVE SCREEN Background to the Invention This invention relates to electronic devices suitable for use by visually impaired people.

Electronic devices such as PDAs (personal digital assistants) generally have keypads to allow the user to interact with the device, e. g. to input data or to select functions. Such devices may also have touch-sensitive screens that allow the user to interact by tapping on displayed buttons or icons, or by drawing on the screen with a stylus.

It has been proposed that electronic devices such as PDAs could be very useful to visually impaired people, for example as talking books, with the audio stored on memory cards. However, a problem with this is that such users may have difficulty in using conventional keypads for interacting with the device.

Also, touch-sensitive screens are not much assistance if the user cannot see the display.

The object of the invention is to provide a novel arrangement for an electronic device, suitable for use by visually impaired people.

Summary of the Invention According to the invention an electronic device includes a touch-sensitive screen, and an overlay positioned over the screen, the overlay comprising a plurality of buttons which, when pressed, touch respective predetermined locations of the screen.

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Brief Description of the Drawings Figure 1 shows a PDA having a touch-sensitive screen, with an overlay including a number of buttons.

Figure 2 is a cross-section through one of the buttons.

Description of an Embodiment of the Invention One embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

Figure 1 shows a PDA (personal digital assistant) 10, including a keypad 12 and a touch-sensitive screen 14. An overlay or template 16 is arranged to fit over the screen. The overlay 16 may be held in place by any convenient means; for example it may be arranged to snap-fit over the screen.

The overlay 16 comprises a generally flat membrane of resilient material, the same shape and size as the screen 14, with a number of buttons 18 on its upper surface. The buttons 18 carry tactile symbols, such a Braille characters, on their upper faces. The size of the screen may typically be about 8cm X 5cm, which allows room for around 25 to 30 buttons on the overlay.

The overlay 16 may conveniently be formed by a rubber moulding process, similar to that used to construct mobile telephone keypads. This is a very cheap process, and the resulting product is very durable.

Figure 2 shows one of the buttons 18 in more detail. The button comprises a raised dome portion 20, and a downwardly-extending plunger portion 22. The plunger portion stops just above the lower surface of the membrane. Thus, when the overlay is in place, the plunger portion 22 does not normally touch the screen 14. However, when the button 18 is pressed, the dome portion 20

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deforms, allowing the plunger portion to move downwards and to touch the screen.

In summary, it can be seen that the overlay allows the user to tap in precise locations of the touch-sensitive screen, without actually having to see the screen.

Software applications the PDA are designed to enable user interaction by touching specific regions of the touch-sensitive screen. A standard design of overlay 16, for example a Braille keyboard, may be provided for use by a number of different applications. Alternatively, different application-specific overlays may be designed for different applications.

To save battery power, the PDA is modified to permanently switch off its display and backlight functions (while still enabling its touch-sensitive input function). Switching off the display and backlight functions may be achieved by software on some PDAs, while on others a hardware modification may be required.

The PDA may also provide speech input and synthesised speech output, to further improve its usability.

Some possible modifications It will be appreciated that many modifications may be made to the system described above without departing from the scope of the present invention. In particular, the invention is not restricted to use with a PDA, but may be applied to any form of electronic device having a touch-sensitive screen, such as for example an ATM (automated teller machine) or computer kiosk.

Claims (7)

1. CLAIMS 1. An electronic device including a touch-sensitive screen, and an overlay positioned over the screen, the overlay comprising a plurality of buttons which, when pressed, touch respective predetermined locations of the screen.
2. 2. An electronic device according to claim 1 wherein the overlay comprises a membrane of flexible material with buttons integrally formed on it.
3. 3. An electronic device according to claim 1 or 2 wherein the buttons carry tactile symbols.
4. 4. An electronic device according to any preceding claim wherein the display function of the touch-sensitive screen is disabled, while enabling its data input function.
5. 5. An electronic device according to any preceding claim, wherein the overlay is removably attached in position over the screen.
6. 6. An electronic device according to any preceding claim, wherein the device is a personal digital assistant.
7. 7. An electronic device substantially as hereinbefore described with reference to the accompanying drawings.