GB2354572A

GB2354572A - Touch- or proximity-sensitive switch for a computer pointing device

Info

Publication number: GB2354572A
Application number: GB9920713A
Authority: GB
Inventors: Robert Edward Pearson
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-01
Filing date: 1999-09-01
Publication date: 2001-03-28
Also published as: GB9920713D0

Abstract

A pointing device for a computer, such as a trackball (Figures 3, 4), a device integrated into a keyboard (Figure 5), or, as shown, a mouse 10, has one or more sensitive regions 22 to replace the conventional mouse or equivalent button. Each sensitive region is sensitive to the touch of or the proximity of a user's finger, which may, in the embodiments, bridge electrodes, block the transmission of light, trigger an infra-red sensor, or change the capacitance of an electrical conductor. By avoiding the need for finger pressure to be applied, the device may reduce the likelihood of adverse physiological conditions in the user, such as repetitive strain injury.

Description

2354572 Pointing Device The present invention relates to a pointing

device. In particular, it relates to a pointing device which can be used by a user of a computer to interact with objects displayed on a graphical user interface of the computer. A typical pointing device enables a user to carry out at least two functions: to move a cursor on a display screen and to send a signal to a computer to activate or select an object on the display. This invention is most particularly concerned with the latter of these functions.

The most widely used type of pointing device is normally referred to as a mouse. A mouse has a body which is supported for use on a surface. Within the body, there are operational components that detect movement of the body on the surface and send electronic signals to a computer indicative of that movement. This performs the first of the functions described above. The body also carries at least one switch (known as a "mouse button"), typically on an upper surface, two or three switches being most common. Upon a switch being pressed, normally by a user's finger, a signal is sent to a computer. This performs the second of the above-described functions.

There is a current concern that use of computers for an extended time can cause physiological harm to a user. In particular, there is concern over a condition known as repetitive strain injury (abbreviated to RSI). While this is a condition often associated with use of a keyboard, there is also concern that extensive use of a pointing device can give rise to RSI, particularly in a finger commonly used to operate a switch on a mouse or another pointing device.

An aim of this invention is to provide a pointing device which is less likely to give rise to RSI in a user.

From a first aspect, the invention provides a mouse for a computer including a body, the body having one or more sensitive regions, each sensitive to the touch of or the proximity of a user's finger, and to generate a signal in response thereto, which signal is indicative to a computer that a mouse button has been pressed. The or each sensitive region performs a function equivalent to a mouse button. However, a user I 2 need not apply force to a sensitive region in order to operate it, so reducing the strain on the user's fingers, hand and wrist.

From a second and more general aspect the invention provides a pointing device having one or more touch sensitive or proximity sensitive regions. In the most general case, this avoids the need for a user to actually press a button. Touching or merely approaching the sensitive region is sufficient to trigger a mouse event.

In such a pointing device the or at least one of the sensitive regions may be an optical sensitive region which is sensitive to optical conditions. Typically, a signal is generated indicative of a mouse button press when the optical sensitive region is obscured from ambient light, and a signal is generated indicative of a mouse button release when the optical sensitive region is exposed to ambient light. Advantageously, a signal is generated only in the event that the level of light to which the optical sensitive region is exposed changes at greater than a predetermined rate and/or the level of light to which the optical sensitive region is exposed changes by an amount greater than a predetermined threshold.

A pointing device embodying the invention may include a body, a light sensitive device mounted within the body, and an aperture in the body through which light can pass from outside of the body to strike the light-sensitive device. In such a pointing device, the aperture preferably has a maximum dimension not greater than 1 cm so that it can be completely covered by a user's finger tip. More preferably, the aperture has a maximum dimension of not greater than 0.5 cm.

In some embodiments of the invention, at least one sensitive region is an electrical sensitive region sensitive to a change in electrical conditions. Most typically, the electrical sensitive region comprises at least two electrodes, and circuitry is provided which can detect completion or interruption of an electrical interconnection between the electrodes. The electrodes are preferably spaced apart by an insulating region of width not greater than I cm, and more preferably by less than 0. 5 cm. This is to enable a user to interconnect the electrodes by touching them with his or her fingertip. However, they should not be so close as to be prone to conductive bridging 3 with dirt or other material.

The electrodes may have a periphery which lies on a locus which is circular, elliptical, rectangular or otherwise polygonal in shape. One electrode may be partially or entirely surrounded by another of the. electrodes. Their shape may be selected to present a favourable aesthetic appearance, they may be in the shape of a manufacturer's trade mark or any other symbol.

A pointing device embodying the invention may typically have two or three sensitive regions. As such, it can act as a direct replacement for a convention two button or three-button mouse. However, in other embodiments, there may be four or more sensitive regions. Particularly, but not exclusively, in embodiments according to the last-preceding sentence, the function of at least one of the sensitive regions is programmable by a user. The functions programmed may, for example, include generation of a double-click, toggling a button press on and off, or emulation of keyboard key presses such as cursor movement key presses.

In yet a further alternative arrangement, at least one of the sensitive regions is an infra-red sensitive region sensitive to detect a source of infra-red radiation placed adjacent to the sensor. Such a sensor may detect heat generated by a user's fingertip.

A pointing device according to the invention may be embodied as a mouse, a trackball, or may be constructed integrally with a keyboard for example, a keyboard of a portable computer.

A pointing device embodying the invention may further include a switch (such as a conventional mouse button) operable by a user to send a signal to a computer. This switch could be used for a secondary function which is carried out sufficiently infrequently to render unlikely the occurrence of RSL Embodiments of the invention will now be described in detail, by way of example'only and with reference to the accompanying drawings in which:

Figures 1 and 2 are plan and side views of a mouse being a first embodiment of the invention; 4 Figures 3 and 4 are plan and side views of a track ball being a second embodiment of the invention; and Figure 5 shows an embodiment of the invention incorporated into the keyboard, for example of a portable computer.

With reference first to Figures I and 2, a first embodiment of the invention is in the form of a mouse. The mouse comprises a body 10 within which is contained electronic and other components. Several pads 12 are mounted on a lower surface of the body 10, the pads serving to support the body on a surface 14, such that it can slide smoothly over the surface 14. In this example, the components within the body 10 include a conventional system for tracking movement of the mouse over a flat surface.

These components include a ball 16 which projects from the lower surface of the body to contact the surface 14. Rotational movement of the ball 16 is detected by components within the body 10, and this in turn causes signals to be sent along a connecting lead 18 to a computer to which the mouse is connected. This much of the construction of the mouse is conventional, and will not be described further.

An upper surface of the body 10 has an opening 20 within which is located a light-transmissive window. Within the body 10, located below the opening 20, is a light sensitive device. In this embodiment, the light sensitive device is a phototransistor 22. However, it could be one of a number of alternative devices sensitive to light at levels in which a computer is typically used.

Intemally of the body, the phototransistor is connected to interface circuitry suitable for generating output signals to be fed to a computer through the connecting lead 18. The circuitry is configured such that a signal indicative to the computer that a mouse button has been pressed is generated in the event that there is a reduction in the amount of light reaching the phototransistor 22. Such a reduction of light can typically be caused by a user moving his or her finger over the opening 20. Upon the light reaching the phototransistor returning to its original level, the circuitry is configured such that a signal indicative to the computer that a mouse button has been released is generated. Therefore, the user can generate a mouse button events without having to press a button or even touch the mouse.

In the mouse shown in Figures 1 and 2, a right-handed user can rest his or her hand on the body 10, with the palm on the hand towards the right as shown in Figure 1, and the fingers extending leftwards. Normally, the user's index finger will rest on the body adjacent to the opening 20. To initiate a mouse click, the user need simply slide his or her index finger to briefly cover the opening 20.

The opening 20 is preferably dimensioned such that it can be substantially completely obscured by a user's finger tip. In this example, it is approximately square and has a dimension of somewhat less than I cm.

A second opening 26 is formed in side wall of the body 10. A push-button 28 projects a small distance from the opening 26. The push-button is disposed to operate a microswitch connected to circuitry within the body 10. The circuitry is configured such that a signal indicative to the computer that a secondary mouse button has been pressed is generated in the event that the push-button 28 is pressed to operate the microswitch, and like 'wise such that a signal indicative to the computer that a secondary mouse button has been released is generated when the push-button 28 is released to open the microswitch.

Although just one sensitive region is shown in this example, more could be provided to increase functionality of the mouse, for example, as shown in dotted lines.

There are many refinements possible to this basic system most particularly enable a user to generate mouse click signals reliably and without generating such signals accidentally.

First, it is most preferable that the device should not interpret a gradual diminution of ambient light levels as an event that should generate a mouse click signal.

Similarly, where ambient light levels are very high, the level of light reaching the phototransistor may remain high even when the opening 20 is covered by a user's finger. Therefore, the circuitry is, in preferred embodiments, configured to generate a mouse click signal in the event of a rapid change in light levels, and to ignore gradual 6 changes. Preferably, a threshold level can be programmed by a user. This can be achieved readily by a skilled person for example using differentiation circuit or a high pass filter to process the output of the phototransistor.

It is also to be preferred that the user should be able to adjust the degree and duration of the opening being obscured that is required to cause a mouse click signal to be generated. Some users may wish only a very fleeting and partial coverage of the opening 20 to cause a mouse click signal to be generated, while other users may prefer that all but complete obscuration of the opening should be ignored.

Some operating systems give special treatment to two mouse button click signals being received within a predetermined short period (a so-called "double click"). This may be achieved by a user obscuring the opening twice in quick succession.

With reference now to Figures 3 and 4, there is shown a second embodiment of the invention. The second embodiment takes the form of a trackball. The trackball comprises a body 40 within which a ball 42, typically of hard plastic or rubber-like material, is contained in a recess 50. A portion of the ball 42 projects from an upwardly directed surface of the body 40. Within the body, sensors are provided which detect rotary movement of the ball 40, signals from the sensors being processed by circuitry within the body 40. The sensors and the circuitry are configured such that rotation of the ball causes signals to be sent to a computer, the signals corresponding to those generated by a mouse as it is moved. By this arrangement, a user can control the position of a mouse pointer on a display by rotating the ball 42, typically using his or her thumb.

Adjacent to the recess 50, also on the upper surface of the body 40, are several sensitive regions 44. Each sensitive region 44 comprises two electrodes 46,48 spaced from one another by a distance somewhat less than the width of a typical human fingertip' The electrodes 46,48 are separated by an insulating region 52, and have an exposed electrically-conductive surface. Each of the electrodes is connected to circuitry within the body 40.

7 In this embodiment, the circuitry is configured to detect the presence or absence of an electrically conductive path between the electrodes 46,48 of each sensitive region.

In particular, the circuitry is sufficiently sensitive to be able to detect the conductive path created by a user's finger making simultaneous contact with both of the electrodes 46, 48. Upon detection of a connection being made between the electrodes 46,48, the circuitry causes a signal to be sent to a connected computer indicative that a mouse button has been pressed. Subsequently, upon interruption of such a connection, the circuitry causes a signal to be sent to a connected computer indicative that a mouse button has been released. As will be understood, the user need only touch the electrodes to carry out an action directly equivalent to pressing a button of a conventional mouse, thereby reducing strain on the user's fingers.

This embodiment has four sensitive regions (naturally, alternative embodiments may have more or less). The circuitry may be configured such that the sensitive regions perform a variety of functions. Most straightforwardly, the circuitry may be configured is such that two of the sensitive regions emulate respectively the buttons of a conventional two-button mouse. The circuitry may be configured such that the other two sensitive regions perform other functions. For example, activation of one of the sensitive regions may cause signals to be generated which emulate a double-click of a conventional mouse. Another button may act like a toggle switch. That is to say, one activation of the sensitive region sends to a computer signals that emulate the pressing of a mouse button, and a subsequent activation of the sensitive region sends to a computer signals that emulate the release of a mouse button. In this way, the total number of operations that a user must carry out is reduced, so reducing the strain on the user's hand.

Turning now to figure 5, there is shown in plan a keyboard 60 of a type found in some portable computers. In this type of computer, movement of a pointer on the display screen is controlled by a small joystick 62 mounted to project upwardly at the centre of the keys 64 of the keyboard 60. Conventionally, such keyboards are further provided with two push-buttons, each of which operates a respective microswitch to serve the same function as the buttons of a conventional mouse.

In this embodiment, the keyboard includes two sensitive areas 66 on an 8 upwardly-directed surface adjacent to the keys. These sensitive areas may, for example, be similar to those described above in relation to either embodiment, or they may take other forms. However, an alternative arrangement will now be described.

Each sensitive area 66 includes an aperture 70 extending through a horizontal surface of the keyboard. The aperture is approximately square and somewhat less than 1 cm in dimension. Each aperture has closure being a sheet of material which may be transparent, or, for aesthetic reasons, by at least partially opaque to visible light. The material of the closure is selected to be transparent to infra-red radiation. Within the keyboard 60, with its sensitive element directed towards the closure, is a phototransistor 72 sensitive to infra-red radiation.

I Internally of the body, the phototransistor is connected to interface circuitry suitable for generating output signals to be fed to the processor of the computer of which the keyboard is part. The circuitry is configured such that a signal indicative to the computer that a mouse button has been pressed is generated in the event that there is an infra-red source is detected by the phototransistor 72 near to the closure. Such an infra-red source can typically be a user's finger placed over the opening 70. the circuitry is configured such that upon detection by the phototransistor 72 of removal of the infra-red source, a signal indicative to the computer that a mouse button has been released is generated. As with preceding embodiments, the user can generate a mouse button event without having to press a button or even touch a push buttons.

Alternative types of sensitive region could be employed. One example of such a region detects the approach or contact of a user's finger by monitoring changes in electrical capacitance of an electrical conductor. This type of sensitive region can operate without the need for a user to come into electrical contact with a conductive element.

Features from the above described embodiments can readily be interchanged between the embodiments. Most particularly, the various sensors disclosed could be used on different types of pointing device. Moreover, it will be very apparent to those skilled in the art that embodiments of the invention can be constructed using a wide 9 variety of sensors in many various types of pointing device. Furthermore, such sensors may be,provided in addition to conventional switches, wheels, and other features commonly deployed on pointing devices..

I

Claims

1. A mouse for a computer including a body, the body having one or more sensitive regions, each sensitive to the touch of or the proximity of a user's finger, and to generate a signal in response thereto, which signal is indicative to a,computer that a mouse button has been pressed.

2. A pointing device for use with a computer having one or more touch sensitive or proximity sensitive regions.

3. A pointing device according to claim 2 in which the or at least one of the sensitive regions is an optical sensitive region which is sensitive to optical conditions.

4. A pointing device according to claim 3 in which a signal is generated indicative of a mouse button press when the optical sensitive region is obscured from ambient light.

5. A pointing device according to claim 3 in which a signal is generated indicative of a mouse button release when the optical sensitive region is exposed to ambient light.

6. A pointing device according to claim 4 or claim 5 in which a signal is generated only in the event that the level of light to which the optical sensitive region is exposed changes at greater than a predetermined rate.

7. A pointing device according to any one of claims 4 to 6 in which a signal is generated only in the event that the level of light to which the optical sensitive region is exposed changes by an amount greater than a predetermined threshold.

8. A pointing device according to any one of claims 3 to 7 which includes a body, a light-sensitive device mounted within the body, and an aperture in the body through which light can pass from outside of the body to strike the light sensitive device.

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9. A pointing device according to claim 8 in which the aperture has a maximum dimension not greater than 1 cm.

10. A pointing device according to claim 8 in which the aperture has a maximum dimension of not greater than 0,5 cm.

11.A pointing device according to any preceding claim in which at least one sensitive region is an electrical sensitive region sensitive to a change in electrical conditions.

12. A pointing device according to claim 11 in which the electrical sensitive region comprises at least two electrodes, and circuitry is provided which can detect completion or interruption of an electrical interconnection between the electrodes.

13. A pointing device according to claim 12 in which the electrodes are spaced apart by an insulating region of width not greater than 1 cm.

14. A pointing device according to claim 12 in which the electrodes are spaced apart by an insulating region of width less than 0.5 cm.

15. A pointing device according to any one of claims 12 to 14 in which the electrodes have a periphery which lies on a locus which is circular, elliptical, rectangular or otherwise polygonal in shape.

16. A pointing device according to any one of claims 12 to 15 in which one electrode is partially or entirely surrounded by another of the electrodes.

17. A pointing device according to any preceding claim having two or three sensitive regions.

18. A pointing device according to any one of claims 1 to 10 having four or more sensitive regions.

19. A pointing device according to any preceding claim in which the function of at least one of the sensitive regions is programmable by a user.

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20. A pointing device according to any preceding claim in which at least one of the sensitive regions is an infra-red sensitive region sensitive to detect a source of infra-red radiation placed adjacent to the sensor.

21. A pointing device according to any preceding claim in which the sensitive regions are disposed to approximate the positions of a user's fingers on the pointing device.

22. A pointing device according to any preceding claim embodied as a mouse.

23. A pointing device according to any preceding claim embodied as a trackball.

24. A pointing device according to any preceding claim constructed integrally with a portable computer.

25. A pointing device according to any preceding claim further including a switch operable by a user to send a signal to a computer.

26. A pointing device substantially as herein described with reference to the accompanying drawings.