GB2309325A

GB2309325A - Trackpad for a computer

Info

Publication number: GB2309325A
Application number: GB9626462A
Authority: GB
Inventors: Steven D Gluskoter; Bryan F Howell; Christopher J Stringer
Original assignee: Dell USA LP
Current assignee: Dell USA LP
Priority date: 1996-01-05
Filing date: 1996-12-20
Publication date: 1997-07-23
Also published as: JPH09297643A; GB9626462D0; FR2743433A1; KR19980041663A; JPH113162A; DE19653775A1; FR2745401A1; KR19980041664A; DE19653854A1; CA2193444A1; TW364972B; GB9626469D0; GB2309009A

Description

2309325 TRACKPAD FOR A COMPUTER This invention relates to trackpads for

computers. The invention particularly relates to trackpads for a portable computer.

In recent years personal computers ("PCs"), in general, and portable computers, in particular, have made considerable gains in both popularity and technical sophistication. Portable, battery-powered computers have become increasingly popular over the last several years due to their light weight and small size that permit them to be easily hand-carried in an ordinary briefcase and used by business travelers in cramped spaces, such as on airline seat back trays, lacking electrical plug-in facilities. One factor contributing to the increasing popularity of the notebook computer is its ever-decreasing size and weight, a factor arising from the ability to fabricate various components of the computer in smaller and smaller sizes while, in many cases, increasing the operating speed and decreasing the power utilization requirements of such components. In fact, a particularly small type of portable computer, the notebook computer, is very popular, generally having dimensions of 85' x 1 V' and a weight of less than 8 pounds. For purposes of this discussion, 91 portable" and "notebook" are synonymous terms. The modern portable computer typically incorporates both hard and floppy disk drives, a monitor screen built into its lid portion, and a keyboard built into its main body portion. It is thus a fully self-contained computer able to be used in situations and locations in wbich the use ofa much larger desktop computer is siniply not feasible. While portable computers were at one time often ernployed as all adjunct to a primary desktop coniputer, the increased power of'suell computers has allowed theni to beconie many users' priniary computers.

One continuing challenge in the design ot'notebook computers, however, is the keyboard structure. Tlils design cliallenge has, to tlils point, arISCII k - 1 BAD ORIGIM.AL:1#. j from two conflicting design goals - the desire even further to reduce the size of the keyboard structure, and the desirability of having the notebook computer emulate as closely as possible the size and typing "feel" of a desktop computer keyboard. The size of the typical human hand is the driving force behind the latter of the two requirements, substantially limiting the amount of miniaturization that can be wrought.

Designers have begun to realize, however, that there is yet a third design goal, brought about as a result of medical studies regarding the degree of stress inflicted on a user's arms, wrists and hands during the act of typing and economically reinforced by costly litigation instigated by computer users who have found themselves the victim of carpal tunnel syndrome or related muscular or joint maladies. Muman factors engineering" or "ergonomics" have become terms of art for design engineering directed to optimum usability by the human body. In the case of keyboards, it has been recognized that, by splitting a keyboard into portions and changing the relative horizontal orientation of the portions, a keyboard may be rendered less strenuous to use, potentially decreasing the likelihood of injury and increasing user productivity by significantly increasing typing comfort.

However, the ergonomic keyboards developed to date have been exclusively for desktop computers, because there are no practical spatial limitations on a desktop to hinder the keyboard's size. It is similarly desirable to provide an ergonomic keyboard for portable computers. However, portable computers continue to decrease in size, certainly complicating tile design of an ergonomic keyboard. Therefore, keyboard designers have onl.,. now begun to turn their attention to creating ergonomic keyboards for such computers that accommodate the spatial restrictions.

There are, of course, two dimensional factors that may be varied to reduce the size ofa notebook computer keyboard structure its vertical or thickness dimension and its horizontal dimensions its length and Several restraints are presented when attempts are made to reduce the overall thickness of a notebook computer keyboard. One possibility thal has been investigated and atteinpted is to slinply reduce the keystroke distance in the notebook computer keyboard compared to its desktop counterpart. An BAD INAl- 3 example of this type of keyboard is a "membrane" keyboard often found on microwave ovens or cash registers. Using this design technique, the overall thickness of the notebook computer in its closed storage and transport position may be correspondingly reduced. However, this thickness reduction in the overall notebook computer, achieved by reducing the keyboard keystroke distance, creates what many users consider to be a degradation in typing "feel" compared to the longer keystroke distance typically found in a larger desktop computer keyboard.

It is more desirable, however, to effect a size reduction in the horizontal direction, as so-called "subnotebook" computers are larger by far in their horizontal dimensions and therefore would benefit most from a reduction therein. Unfortunately, similar restrictions have also been experienced when attempting to reduce the horizontal dimensions of a keyboard. The number, size, and relative spacing of the manuallydepressible key cap portions of a keyboard govern the keyboard's horizontal dimensions. Various reductions in these three dimensional factors may be used to reduce the overall length or width of the keyboard. However, prior art attempts to reduce these three factors to gain a keyboard size reduction have correspondingly lessened the similarity of the notebook computer keyboard in appearance, key arrangement and typing feel to its desktop counterpart. Keyboards having a smaller key size or spacing are therefore often derisively referred to as "chicleC keyboards.

Trackpads for moving a cursor or other symbol on a computer display screen are known. The pad has a shape that corresponds to the shape of the display on which the cursor is being controlled through the pad. A user applies a finger to the trackpad and moves it across the pad surface to vary the position of the cursor on the display. Although the pad is substantially smaller than the screen, it has been found that a user may tend to associate the absolute position of the finger on the pad with the position of the cursor on the screen. The movement of the cursor across the screen in any direction has to take more than one sweep of the finger across the BAD ORIGINAL A 1 4 pad if the pad is not to be too sensitive to finger movement and, thus, be difficult to use. Because users may tend to associate too closely the position of the cursor with the position of the f inger on the pad, the efficiency of the user of the trackpad can be impaired. This is because the area in which it is possible to move the f inger to drag the cursor quickly becomes restricted. This is particularly the case when the area of activity on the display is concentrated at one edge or in a corner.

To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide a trackpad that a user is less likely to associate with the display as a whole and, therefore, use to better effect to move a symbol on the screen.

The invention independent claims. the dependent claims.

In one form the invention provides a portable computer comprising a first chassis portion hingedly coupled to a second chassis portion to allow relative rotation between a closed position wherein said first and second chassis portions substantially overlay one another to enclose interior surfaces thereof and an open position wherein said first chassis portion is rotated away from said second chassis portion to expose said interior surfaces thereof; a display screen, associated with said first chassis portion, for displaying a symbol thereon; data processing and storage circuitry contained within said second chassis portion and coupled to said display screen via a cable located proximate a hinge structure coupling said firsi and second chassis porti,ns; and a trackpad, coupled to said data processing and storage is defined in the accompanying Preferred features are recited in 1 BAD ORIGINAL 30- circuitry, for receiving a stimulus applied by a user on a touch- sensitive surface thereon and generating, in response thereto, a command signal to move said symbol a relative distance on said display screen as a function of a relative magnitude by which said user displaces said applied stimulus across said surface, a shape of said touch-sensitive surface being different from a shape of said screen to dissuade said user from perceiving that an absolute location on said touch-sensitive surface corresponds to an absolute location on said display screen.

is A particular form of the method provides a method of manufacturing a portable computer, comprising the steps of hingedly coupling a first chassis portion to a second chassis portion to allow relative rotation between a closed position wherein said first and second chassis portions substantially overlay one another to enclose interior surfaces thereof and an open position wherein said first chassis portion is rotated away from said second chassis portion to expose said interior surfaces thereof; associating a display screen with said first chassis portion, said display screen adapted to display a symbol thereon; containing data processing and storage circuitry within said second chassis portion, said data processing and storage circuitry coupled to said display screen via a cable located proximate a hinge structure coupling said first and second chassis portions; and coupling a trackpad to said data processing and storage circuitry, said trackpad adapted to receive a stimulus applied by a user on a touch-sensitive surface thereon and generate, in response thereto, a command signal to move said symbol a relative distance on said display screen as a function of a relative magnitude by which said user displaces said applied stimulus across said BAD ORIGINAL JO 6 surface, a shape of said touch-sensitive surface being different from a shape of said screen to dissuade said user from perceiving that an absolute location on said display screen.

The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from scope of the invention in its broadest form.

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

BAD C)RIGINAL J0) FIGURE 1 illustrates an isometric view of a portable computer in an open position having a first embodiment of an ergonomic keyboard constructed according to the present invention, the keyboard having a fixed pointing device portion and shown in a deployed position; FIGURE 2 illustrates an isometric view of the portable computer of FIGURE 1 in a closed position and wherein the first embodiment of the keyboard is shown in a stowed position; FIGURE 3 illustrates an isometric view of the portable computer of FIGURE 1 in the open position and wherein the first embodiment of the keyboard is shown in a stowed position; FIGURE 4 illustrates a plan view of the first embodiment of the keyboard shown in the stowed position; FIGURE 5 illustrates a plan view of the keyboard of FIGURE 4 shown in the deployed position; FIGURE 6 illustrates a plan view of a second embodiment of the keyboard having a slidable pointing device portion and shown in the stowed position; FIGURE 7 illustrates a plan view of the keyboard of FIGURE 6 shown in the deployed position; FIGURE 8 illustrates a plan view of a third embodiment of the keyboard having a fixed pointing device portion and a modified return spring structure and shown in the stowed position; FIGURE 9 illustrates a plan view of the keyboard of FIGURE 8 shown in the deployed position; FIGURE 10 illustrates a plan view of a fourth embodiment of the keyboard having a fixed pointing device portion and a modified linkage and shown in the deployed position; and FIGURE 11 illustrates a graphical representation of task completion time as a function of target size.

Refeming initially to FIGURE 1, illustrated is an isometric view ofa portable coinputer 100 in an open position. The computer 100 may be an IBM PC-compatible computer, an Apple Macintosh@ computer or a portable computer of other logical architecture. The present invention is in no manner limited by the particular structure, function, logical architecture or compatibility of the computer 100.

The computer 100 comprises a first chassis portion 110 and a second chassis portion 120 coupled to the first chassis portion 110 by a hinge structure 142. The hinge structure 142 allows the first and second chassis portions 110, 120 to rotate relative to one another between a closed position (as illustrated in FIGURE 2) wherein the first and second chassis portions substantially overlay one another to enclose interior surfaces 111, 121 thereof. A conventional latch 112 and corresponding latch receiver 122 cooperate to maintain the computer 100 in the closed position until released.

The hinge structure 142 further allows the first chassis portion 110 to rotate away from the second chassis portion 120 to the open position shown. In the open position, the interior surfaces 111, 121 are exposed for access by a user. The first chassis portion 110 has a display screen 130 associated therewith. The display screen 130 is conventionally adapted to receive and display output data produced by conventional general purpose data processing and storage circuitry (schematically represented and designated 140) usually contained within the second chassis portion 120.

The computer 100 is shown as having a first embodiment of an ergonomic keyboard 150 constructed according to the present invention and shown in a deployed position. The keyboard 150 comprises a lefthand keyboard portion 160 and a righthand keyboard portion 170. For purposes of' the present invention, the Mrst keyboard portion" alternatively refers to either the lefthand keyboard portion 160 or the righthand keyboard portion 170. Likewise, the "second keyboard portion" alternatively refers to the other of either the lefthand keyboard portion 160 or the righthand keyboard portioll 170. Each of the lefthand and nightliand keyboard portions 160, 170 [)ears a plurality of indiVidually-depressible keys (to be referenced in subsequent FIGUREs) that are electrically coupled to the general purpose (JaLi processing and storage circuitry 140 to provide a ineans by which a user inay---enerate input data for the computer 100.

BAD 081GINAL.4) The lefthand and righthand keyboard portions 160, 170 are coupled to an underlying baseplate 181 by separate pivots (to be illustrated in subsequent FIGUREs), allowing the lefthand and righthand keyboard portions to pivot or rotate relative to the second chassis portion 120. The baseplate 181 is coupled to and made a part of the second chassis portion 120. A linkage 140 couples the lefthand and righthand keyboard portions 160, 170 together, such that an n clockwise rotation by the lefthand keyboard portion 160 results in a corresponding n' counterclockwise rotation by the righthand keyboard portion 170, within travel limits to be described. A position locking structure 188 (to be described more fully) presents a vertical ratchet, allowing the user to fix a particular desired orientation of the lefthand and righthand keyboard portions 160, 170. It should be understood that, in the alternative, separate structures within the second chassis portion 120 may support the lefthand and righthand keyboard portions 160, 170, thereby eliminating a need for the baseplate 181 to be in one piece.

As previously mentioned, one of the findings of ergonom ic research is that a proper lateral orientation of keyboard keys appears to be beneficial in reducing injury due to repeated typing movement while the user's wrists are under strain. In a manner to be described, the present invention allows a user to deploy the keyboard 150 by splaying the lefthand and righthand keyboard portions 160, 170 to reorient the keys thereon into an ergonomic presentation for the benefit of the user. "Ergonomic presentation" therefore is defined, for purposes of the present invention, as being a presentation that takes into account the user's human anatomy.

The first embodiment of the keyboard 150 of the present invention illustrated in FIGURE 1 has a fixed pointing device portion 182. The pointing device portion 182 bears a trackpad 183 (or a trackball or other pointing device, as appropriate) and lefthand and righthand momentary switches (or "buttons") 185, 187. It should be appreciated that, from the point of view of an input device, the pointing device portion 182 functions as a mouse, providing a means by which a user may point (the trackpad 183) and a means by which the user may click or drag (the lefthand and righthand buttons 185, 187).

Further, each of the lefthand and righthand keyboard portions 160, 170, includes paImrests 184, 186. The palnirests 184, 186 provide further ergonomic advantage by freeing the user's hands of the weight of the user's forearms. As the computer 100 may be a multimedia computer having the ability to generate stereo sound for the benefit of the user, the palinrests 184, 186 further provide an area for speakers located under speaker grilles (not separately referenced). Alternatively, the speaker grilles may be located on side surfaces of the computer 100.

Turning now to FIGURE 2, illustrated is an isometric view of the portable computer 100 of FIGURE 1 in a closed position and wherein the first embodiment of the keyboard 150 is shown in a stowed position. FIGURE 2 is presented primarily for the purpose of illustrating that the lefthand and righthand keyboard portions 160, 170 collapse to within a footprint of the computer 100 when the keyboard 150 is in its stowed position. The pointing device portion 182 likewise falls within the footprint of the computer 100. Again, the latch 112 allows the user to release the first chassis portion 110 from the second chassis portion 120 for relative rotation therewith by means of the hinge structure 142.

Turning now to FIGURE 3, illustrated is an isometric view of the portable computer 100 of FIGURE 1 in the open position and wherein the first embodiment of the keyboard 150 is shown in a stowed position. FIGURE 3 is presented primarily for the purpose of illustrating that the keyboard 150 remains fully accessible to the user and operative when the computer 100 is ill the open position and the keyboard 150 is in the stowed position. Although the plurality of keys of the lefthand and righthand keyboard portions 160, 170 are not off-axis to ease typing stress, they remain functional. Further, the palmi-ests 184, 186 remain available for supporting the user's wrists. Tile pointing device portion 182 further renialns accessible.

Turning now to FIGURE 4, illustrated is a plaii view ofthe first einbodiment of the keYboard 150 showii M Clie stowed positlow Structures that underlie and allow the lwyboard 150 to issuiiie different positions are ine.

shown in broken 1' BAD ORIGINAL JO Again, illustrated are the lefthand and righthand keyboard portions 160, 170, the linkage 180, the pointing device portion 182 (including the trackpad 183 and the lefthand and righthand buttons 185, 187), the palinrests 184, 186 (and associated speakers) and the position locking structure 188.

As previously described, the lefthand keyboard portion 160 supports a plurality of keys 410. Similarly, the righthand keyboard portion 170 supports a plurality of keys 420. The plurality of keys 410 are arranged in rows that align with a lefthand axis 430 defining the orientation of the plurality of keys 410 of the lefthand keyboard portion 160. Likewise, the plurality of keys 420 are arranged in rows that align with a righthand axis 440 defining the orientation of the plurality of keys 420 of the righthand keyboard portion 170. As can be seen, since the keyboard 150 is in its stowed position, the lefthand and righthand axes 430, 440 are substantially parallel and thus aligned with respect to one another.

FIGURE 4 shows a pivot 411 coupling the lefthand keyboard portion 160 to the underlying baseplate 181 and a pivot 421 coupling the righthand keyboard portion 170 to the underlying baseplate 181. The pivots 411, 421 provide a center of rotation for the lefthand and righthand keyboard portions 160 170; in a manner to be illustrated, the various guides that confine the rotation of the lefthand and righthand keyboard portions 160, 170 and otherwise couple the lefthand and righthand keyboard portions 160, 170 to the underlying baseplate 181 are constructed with reference to the pivots 411, 421 and therefore have radii of curvature extending to their respective pivots 411, 421.

A return spring 450 is shown coupled between the baseplate 181 and an underlying surface of the lefthand keyboard portion 160. In the first embodiment of the keyboard 150, the return spring preferably comprises a length of resilient metallic material forming a cantilever arm. Since the keyboard 150 is shown in the stowed position, the return spring 450 is shown as being relatively straight and therefore relatively stress-ftee, with little or no force exerted thereby on the lefthand keyboard portion 160.

A boss 460 is shown extending upward &om the baseplate and engaging through a corresponding arcuate slot 461 in the underlying surface of the lefthand keyboard portion 160. The boss 460 and slot 461 cooperate to confine the rotation of the lefthand keyboard portion to a desired number of degrees (in the illustrated embodiment, about 10'). The boss 460 and slot 461 also prevent the lefthand keyboard portion from separating vertically from the C.

baseplate 181, thereby counteracting a tendency for the lefthand keyboard portion 160 to warp when a user places pressure on the palinrest 184.

Correspondingly, a boss 470 is shown extending upward from the baseplate and engaging through a corresponding arcuate slot 471 in the underlying surface of the righthand keyboard portion 170. The boss 470 and slot 471 cooperate to confine the rotation of the righthand keyboard portion to a desired number of degrees (about 10", preferably to correspond with the confinement of the lefthand keyboard portion 160). The boss 470 and slot 471 also prevent the righthand keyboard portion 170 from separating vertically from the baseplate 181, thereby counteracting a tendency for the righthand keyboard portion 170 to warp when a user places pressure on the palnirest 186.

In practice, it has been found that the slots 461, 471 and other slots employed in the various embodiments of the keyboard 150 of the present invention may present frictional resistance to the movement of any bosses therethrough. Accordingly, it may be advantageous to line the sloes) with plastic or other low-friction material to reduce the resistance and thereby smooth the operation of the keyboard 150.

The linkage 180, as described previously, couples the lefthand and righthand keyboard portions 160, 170 to ensure that they rotate in tandem. In the first embodiment illustrated in FIGURE 4, the linkage 180 comprises a boss 480 fixed to the nighthand keyboard portion 170 and confined within an arcuate slot 482 formed within a member (not separately referenced) fixed to the lefthand keyboard portion 160. As the lettliand and rightliand keyboard portions 160, 170 rotate between the stowed and deployed positions, the boss 480 traverses the slot 482. The slot 482 defines the inovenient ofthe boss 480 and therefore the rotation ofthe righthand keyboard portion 170 1-1xed tliereto.

The position locking structure 180 comprises a plurality of'delents (shown but not separately referenced) fbrined on tlic uii(](i-l.vln,,, surfiace of the BAD ORIGNAL jo 3 lefthand keyboard portion 160 and a corresponding follower (also not referenced) formed on the underlying baseplate 181. As the lefthand keyboard portion 160 rotates between the stowed and deployed positions, the follower traverses the detent-s. The force required to remove the follower from a particular detent preferably exceeds the spring force exerted by the return spring 450. Therefore, the position locking structure 180 allows the user to lock the keyboard 150 at a given position (either the stowed or fully deployed positions or any one of a number of given intermediate positions).

Turning now to FIGURE 5, illustrated is a plan view of the keyboard 150 of FIGURE 4 shown in the deployed position. FIGURE 5 shows how the bosses 460, 470, 480 traverse their corresponding arcuate slots 461, 471, 481. Further, FIGURE 5 shows how the lefthand and righthand axes 430, 440 are misaligned to effect an ergonomic presentation of the pluralities of keys 410, 420 to the user. Assuming that the travel of the lefthand and righthand keyboard portions 160, 170 is limited to 100 clockwise and counterclockwise, respectively, the total misalignment of the lefthand and righthand axes 430, 440 is therefore 20'. Of course, other degrees of misalignment are within the broad scope of the present invention.

Finally, FIGURE 5 more clearly delineates the division of the keyboard keys between the lefthand and righthand keyboard portions 160, 170. On a conventional QWERTY keyboard and, more specifically, on a 101-key IBM PC AT standard keyboard, the dividing line is illustrated as being as follows: between the '77' and '78" on the top row, between the 'W' and '7' keys on the second -from-the- top row, between "T" and "Y" on the third-from-the-top row, between "G" and "H" on the fourth-from-the-top row and between "B" and "N" on the fifth-from-the-top row. As can readily be seen, the spacebar is divided into left and right portions. This represents a conventional division of keys and is evident on more conventional ergonomic keyboards for desktop computers. Of course, other divisions of the keyboard keys are within the broad scope of the present invention.

Turning now to FIGURE 6, illustrated is a plan view of a second embodiment of the keyboard 150 having a slidable pointing device portion 182 and shown in the stowed position. The second embodiment primarily differs k from the first by its introduction of a sliding pointing device portion 182. In other respects, the second embodiment of the keyboard 150 is similar to the first. Accordingly, similar components will not be described again.

An elongated boss 630 protruding from an underlying surface of the pointing device portion 182 slidably couples the pointing device portion 182 to a straight slot 640 in the underlying baseplate 181. The boss 630 is elongated to prevent substantial rotation of the pointing device portion 182 with respect to the baseplate 181. An elongated plate structure 600 extends upward, as shown, from the pointing device portion 182 to the linkage 180, where the elongated plate structure 600 is coupled to an extension plate 611 extending from the lefthand keyboard portion 160 by a hingepin 610 for rotation relative thereto. The elongated plate structure 600 is further coupled to the righthand keyboard portion 170 by a boss 620 residing within an arcuate slot 621 formed in an extension plate (not referenced) fixed to the righthand keyboard portion 170. It is apparent that, as the lefthand keyboard portion 160 is rotated clockwise, the extension plate 611 moves, forcing the elongated plate structure 600downward, as shown (the elongated plate structure 600 includes a hinge 612 to accommodate any lateral movement caused by rotation of the extension plate 611). This causes the pointing device portion 182 to extend toward the user and away from the remainder of the keyboard 150. As the elongated plate 600 moves downward, the boss 620 traverses the slot 621, forcing the righthand keyboard portion 170 into a counterclockwise rotation. This combined action moves the keyboard 150 toward the deployed position.

Turning now to FIGURE 7, illustrated is a plan view of the keyboard 150 of FIGURE 6 shown in the deployed position. As can be seen, the elongated boss 630 has fully traversed the straight slot 640, fully extending the pointing device portion 182 for use.

Turning now to FIGURE 8, Illustrated is a plan view ofa tiilr(l embodiment of the keyboard 150 having a fixed pointing device portion 182 and a. modified return spriing, structure and sliown in tlie stowed position. In the previously-described enibodiments, tlio spring fOree oftlie return spi-11101 450 and the locking floree ofthe position loelcing structure 188 are preferably balanced to allow the keYboard 150 to be nioved between the sto-,..e(l and - 14 apr) OIR1G,1Al- -0 0 v deployed positions without requiring substantial effort on the user's behalf to deploy the keyboard 150 or slamming the keyboard 150 shut.

FIGURE 8 shows an alternative third embodiment that, in some applications, provides a smoother movement for the keyboard 150. As with the second embodiment, only those components that differ from those already described will be described in detail. First, FIGURE 8 shows a plurality of bosses 810, 820 extending from the underlying surface of the lefthand keyboard portion 160 and residing within corresponding arcuate slots 811, 821 in the underlying baseplate 181. The bosses 810, 820 and slots 811, 821 cooperate as before to limit the rotation of the lefthand keyboard portion 160 and to prevent the lefthand keyboard portion 160 from separating from the underlying baseplate 181 (or warping under pressure applied to the paImrest 184). Similarly, FIGURE 8 shows a plurality of bosses 830, 840 extending from the underlying surface of the righthand keyboard portion 170 and residing within corresponding arcuate slots 831, 841 in the underlying baseplate 181. Again, the bosses 830, 840 and slots 831, 841 cooperate to limit the rotation of the righthand keyboard portion 170 and to prevent the righthand keyboard portion 170 from separating from the underlying baseplate 181 (or warping under pressure applied to the palinrest 186).

Lefthand and righthand torsion return springs 870, 880 replace the cantilever arm torsion return spring 450 of the previous embodiments. First ends 871, 881 of the lefthand and righthand torsion return springs 870, 880 are coupled to the underlying baseplate 181. Second ends 872, 882 of the lefthand and righthand torsion return springs 870, 880 are coupled to the underlying surfaces of the lefthand and righthand keyboard portions 160, 170, respectively. As the lefthand and righthand keyboard portions 160, 170 are rotated toward the deployed position, the first ends 871, 881 and second ends 872, 882 of the lefthand and righthand torsion return springs 870, 880 move toward one another, compressing the lefthand and righthand torsion return springs 870, 880 and providing a resistance against further deployment. It is apparent in FIGURE 8 that the lefthand and righthand torsion return springs 870, 880 are not fixed at their respective centers. Therefore, the lefthand and. -hthand torsion return springs 870, 880 exert a variable spring force as the n., lefthand and righthand keyboard portions are rotated. This variable spring force may be balanced to allow deploying and stowing forces to be roughly equal. A boss 850 and arcuate slot 851 form the linkage, coupling the lefthand and righthand keyboard portions 160, 170 together for coordinated rotation.

The position locking structure 188 differs from that previously illustrated in that it comprises a locking plate 860 attached to the underlying baseplate 181 by a pivot 862. The locking plate 860 has a serrated edge 864 containing a plurality of detents. over which a pin 866 travels. The pin 866 is attached to the lefthand keyboard portion 160. A spring 869 biases the locking plate toward counterclockwise rotation, maintaining the serrated edge 864 against the pin 866. A button portion 868 of the locking plate 860 allows a user to overcome the spring force presented by the spring 869. By moving the button portion 868 to the right, as shown, the user may disengage the serrated edge 864 from the pin 866. The keyboard 150 is thereby freed for stowage or deployment, as desired. The button portion 868 may be accessible to a user for direct actuation thereby and, additionally, may be positioned for automatic actuation (such as by the first chassis portion 110 of FIGURE 1, allowing the keyboard 150 to be stowed automatically as the computer 100 of FIGURE 1 is rotated toward its closed position).

The position locking structure 188 provides a horizontal ratchet. A horizontal ratchet is, in many applications, superior to a vertical ratchet, in that the lefthand and righthand keyboard portions 160, 170 are not forced out of their plane of rotation as they are rotated. By keeping the lefthand and righthand keyboard portions 160, 170 in their plane of rotation, the overall stability of the keyboard 150 is improved.

Furthermore, the position locking structure 188 is designed to present a ratchet force that increases as the keyboar(l 1.50 is deployed. The lefthand and righthand torsion return spnncys 870, 880 present a return Ibree that tn decreases as the kevboard 150 is (leployed. When combine(], the ratchet and return forces inost preferably yiel(f a relatively constant foree.

Turning now to FIGURE 9, illustrate(l is a plan view ofthe keyboard 150 of FIGURE 8 shown in the (1(1)1o,v(,(] position. FIG1W 9 is presented BAD ORIGINAL J10 17 primarily for the purpose of showing the change in relative position of the bosses 810, 820 830, 840, 850 with respect to their corresponding arcuate slots 811, 821, 831, 841, 851 as the keyboard 150 assumes its deployed position.

Turning now to FIGURE 10, illustrated is a plan view of a fourth embodiment of the keyboard 150 having a modified linkage 180 and shown in the deployed position. The pointing device portion, although it is fixed, is not illustrated in FIGURE 10 to simplify depiction of the keyboard 150.

The modified linkage 180 eliminates a separate extension plate from the lefthand keyboard portion 160 and is achieved by providing an additional boss 910 protruding from the underlying surface of the righthand keyboard portion 170 for engagement with a corresponding arcuate slot 911 in the baseplate 181. Note again that all arcuate slots 811, 821, 831, 841, 911 have radii of curvature extending to their respective pivots 411, 421.

At this point, it is beneficial to describe in greater detail why the trackpad 183 illustrated in FIGUREs 1 and 3 through 9 is curvilinear or, more specifically, elliptical in shape.

The trackpad 183 was itself the subject of an ergonomic study. The ergonomics being studied were different from that of the ergonomic keyboard 150 described above, in that carpal tunnel syndrome or related muscular or joint maladies were not the consideration. Rather, the learnability or usability of the trackpad was at issue.

Traditionally, trackpads have had a shape corresponding to that of the display screen with which they cooperate. Since such screens are conventionally rectangular, with an aspect ratio at or near 1.311, conventional trackpads were likewise rectangular, with a similar aspect ratio. The user's natural tendency, upon first encountering a conventional trackpad, is to "map" the surface of the trackpad onto the surface of the display screen. In other words, absolute locations on the trackpad correspond to one another in the same manner as absolute locations on the display screen. Intuitively, the user perceived that pressure applied to an upper righthand portion of the touch-sensitive surface of the trackpad would cause some action to take place in the corresponding upper righthand portion of the display screen. For instance, if a pointer symbol were to reside in the upper righthand portion of the display screen, pressure applied by the user to the corresponding upper righthand portion of the touch-sensitive surface of the trackpad would "seizJ (or "acquire") the pointer symbol, allowing the symbol to be dragged about the display screen as the user desired.

Unfortunately, the user's perception is incorrect. Conventional trackpads do not "map" onto conventional display screens. Instead, trackpads provide only for relative motion.

For example, if a pointer symbol were to reside in the upper righthand portion of the display screen and the user were to apply pressure to any location on the touch-sensitive surface ofthe trackpad, the computer forces that location to correspond with the current location ofthe pointer symbol on the display screen. Once the user displaces the applied pressure (as when the user inoves his digit about the surlic() the pointer symbol moves in accordance with the displacement: a move toward the lower lefthand corner of' the trackpad moves the pointer s-,riiil)ol to-,,s,ar(l the lower lefthand corner of' the display screen.

BAD ORIGINAL JO A distinct problem occurs if, for example, the pointer symbol is proximate the periphery of the display screen, perhaps the upper righthand corner. For purposes of this example, it is assumed that the user wishes to move the pointer symbol still closer to the periphery (the upper righthand corner). Given the user's misperception of the relationship that the trackpad bears to the display screen, the user's natural tendency would be apply pressure near the upper righthand corner of the trackpad, dragging toward the upper righthand corner. Unfortunately, the user has placed himself in the very location of the trackpad that most limits his movement in the desired direction. This usually results in the user being forced repeatedly to apply pressure, move a short distance in the desired direction, release pressure, move back a short distance to the lower right and repeat until the pointer symbol has reached its rightful position, resulting in a number of short drags to accomplish the move.

Again, the computer does not correlate locations on the trackpad to locations on the display screen until the user begins to apply pressure to the touch-sensitive surface. Therefore, the user could have applied pressure to the lower lefthand corner, giving himself substantially more room to move toward the upper right and allowing the pointer symbol to be moved toward the periphery (the upper righthand corner in this example) in one long drag.

Of course, users adapt over time, learning that the trackpad does not function as they had originally intuited. However, the fact that the trackpad shape was similar to the shape of the display screen caused the user to make and then break a perception.

The above-mentioned ergonomic study was undertaken to test whether a trackpad having a shape different from that of the display screen would dissuade the user from reaching that initial, erroneous assumption as to how the trackpad is to be used. The study was performed using two notebook computers. The first computer featured a trackpad having a conventional rectangular shape centered in front ofthe keyboard and having an aspect ratio of approximately 1.33:1 and a display screen having a conventional rectangular shape with a conventional approximate 1. 33:1 aspect ratio. The second computer featured an elliptical trackpad centered in front ofthe keyboard and having an aspect ratio of approximately 1.33:1 and a display screen having a conventional rectangular shape with a conventional approximate 1.33:1 aspect ratio.

The study was performed with 12 users, 4 of which had experience with notebook computers subjectively-characterized as beginner-level, 7 of which had intermediate-level experience and 1 of had advanced-level experience. Of the 12 users, only 1 had any experience with trackpads, and that user had only intermediate experience. Of the 12 users, 1 had experience with a mouse characterized as intermediate-level, 3 had advanced-level experience and 8 had expert-level experience. The users employed notebook computers in their daily activities: never (1), rarely (3), occasionally (7) and frequently (1). Ten of the users had experience with integrated trackballs.

All of the users were right-handed, although the central location of the trackpad was not deemed to favor one hand over the other.

The users were asked to acquire 20 targets (taking the form of symbols ranging in size from.13 to 2.08 centimeters) on the display screen in 5 repetitions (yielding a total of 100 blocks) on each of the first and second computers. The time required to acquire the targets (task completion time) was measured. After acquisition, the users were interviewed to determine their subjective preferences relative to the rectangular and elliptical trackpads, FIGURE 11 illustrates a graphical representation of task completion time as a function of target size. It is apparent in FIGURE 11 that elliptical trackpad task completion times (represented by a solid line 1110) were almost always less than rectangular trackpad task completion times (represented by a broken line 1120).

The user's subjective responses mirrored the objective completion times. Nine ofthe 12 users preferred the elliptical trackpad to the conventional rectangular trackpad.

Tlie trackpad aspect of the present invention is by no means limited to an elliptical trackpad. Rather, the trackpad aspect ofthe present invention introduces the broad concept that the shape of the touch- seiisitive suriice of' the trackpad should differ firom the shape ofthe display screen, tliereby BAD OR1GINAL dissociating the two in the user's mind and relieving the user of the task of unlearning the erroneous assumption that he might have otherwise made.

Therefore, the present invention contemplates touch-sensitive surface shapes that are at least partially curvilinear, nonrectangularly polygonal, circular, triangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal, decagonal, and so on. Further, if the display screen assumes a shape other than rectangular, the trackpad can be allowed to assume its conventional rectangular shape. Again, the important concept to understand is that the peripheral shapes of the trackpad and display screen should be different for perceptual dissociation to take place.

The touch-sensitive surface of the trackpad is not required to be planar. Turning back to FIGURE 8, it should be noted that a touch-sensitive surface 890 of the trackpad 183 is shaded, indicating that the touchsensitive surface 890 of the third alternative embodiment is not planar, but is nonplanar instead. The touch-sensitive surface 890 may be convex or concave and may be curved about only a single point (yielding a partially spherical surface), curved about two points separated by a distance that is shorter than a dimension of the touch-sensitive surface 890 (yielding a partially ellipsoidal surface) or curved about two points separated by a infinite distance (yielding a partially cylindrical surface).

From the above description, it is apparent that the present invention provides, for use with a computer having a display screen for displaying a symbol thereon, a trackpad, including a touch-sensitive surface for receiving a stimulus and generating, in response thereto, a command signal to cause the symbol to move a relative distance on the display screen as a function of a relative magnitude of the stimulus, a shape of the trackpad being different from a shape of the screen to dissociate an absolute location on the trackpad from an absolute location on the display screen.

Although the present invention and its advantages have been desenibed in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the scope of the invention in its broadest form.

22

Claims

CLAIMS:

1. A portable computer, comprising:

a first chassis portion hingedly coupled to a second chassis portion to allow relative rotation between a closed position wherein the first and second chassis portions substantially overlay one another to enclose interior surfaces thereof and an open position wherein the first chassis portion is rotated away from the second chassis portion to expose the interior surfaces thereof; a display, associated with the first chassis portion, for displaying a symbol thereon; data processing and storage means contained within the second chassis portion and coupled to the display screen via a cable located proximate a hinge structure coupling the first and second chassis portions; and a trackpad, coupled to the data processing and storage circuitry, for receiving a stimulus applied by a user on a touch-sensitive surface thereon and generating, in response thereto, a command signal to move the symbol a relative distance on the display screen as a function of a relative magnitude by which the user d-'splaces the applied stimulus across the surface, the touch-sensitive surface having a shape which is different from the shape of the screen, such that a tendency of a user to associate an absolute position on the said surface as corresponding to an equivalent position on the display is reduced.

2. A portable computer as claimed in cla---. wherein the shape of the touch-sensitive surface -s at least partially curvilinear.

BAD ORIGINAL 03 23

3. A portable computer as claimed in claim 1, wherein the shape of the touch-sensitive surface is polygonal.

4. A portable computer as claimed in claim 1 or 2, wherein the touchsensitive surface is concave.

5. A portable computer as claimed in claim 1 or 4, wherein the touchsensitive surface is partially ellipsoidal.

6. A method of manufacturing a portable computer, comprising the steps of:

hingedly coupling a first chassis portion to a second chassis portion to allow relative rotation between a closed position wherein the first and second chassis portions substantially overlay one another to enclose interior surfaces thereof and an open position wherein the first chassis portion is rotated away from the second chassis portion to expose the interior surfaces thereof; associating a display screen with the first chassis portion, the display screen adapted to display a symbol thereon; containing data processing and storage circuitry within the second chassis portion, the data processing and storage circuitry coupled to the display screen via a cable located proximate a hinge structure coupling the first and second chassis portions; and coupling a trackpad to the data processing and storage circuitry, the trackpad adapted to receive a stimulus applied by a user on a touch- sensitive surface thereon and generate, in response thereto, a command signal to move the symbol a relative distance on the display screen as a function of a relative magnitude by which the user displaces the applied stimulus across the 24 surface, the touch-sensitive surface having a shape which is different from the shape of the screen, such that a tendency of a user to associate an absolute position on the said surface as corresponding to an equivalent position on the display is reduced.

7. A method as claimed in claim 6, wherein the shape of the touchsensitive surface is at least partially curvilinear.

8. A method as claimed in claim 6, wherein the shape of the touchsensitive surface is polygonal.

9. A method as claimed in claim 6 or 7, touch-sensitive surface is concave.

wherein the

10. A method as claimed in claim 6 or 9, wherein the touch-sensitive surface is partially ellipsoidal.

A computer, comprising: a display screen for displaying a symbol thereon; computing means; and a trackpad, having a iouch- sensitive surface for receiving a stimulus applied by a user and generating, in response thereto, a command signal to move the symbol a distance on the display screen which is a function of the distance by which the user displays the applied stimulus across the said surface, -,-',-ie touch-sensitive surfachaving a shape which is different from the shape c)fscreen, such that a tendeiic:-.- of a user to associa'-absolute position on the saii-i surface as corresponding an equivalent position on the display is reduced.

12.

The computer as recited in claim 11 wherein BAD ORIGNAL shape of the touch-sensitive surface is at least partially curvilinear.

13. The computer as recited in claim 11 wherein the shape of the touchsensitive surface is polygonal.

14. The computer as recited in claim 11 wherein the relative distance and the relative magnitude are scalable with respect to one another.