WO1992002007A1

WO1992002007A1 - Input apparatus providing three degrees of freedom in movement

Info

Publication number: WO1992002007A1
Application number: PCT/US1991/004584
Authority: WO
Inventors: Richard Pekelney
Original assignee: Richard Pekelney
Priority date: 1990-07-26
Filing date: 1991-06-26
Publication date: 1992-02-06

Abstract

An input apparatus indicating three degrees of freedom of movement. The apparatus includes a housing (30), with a support cup accommodating a rotatable trackball (3), an encoder ring (28) radially surrounding the cup and being rotatable independent of the trackball. Sensors detect the direction of rotation of the trackball with respect to X and Y directions, and the direction of rotation of the encoder ring with respect to a Z direction.

Description

INPUT APPARATUS PROVIDING THREE DEGREES OF FREEDOM IN MOVEMENT

BACKGROUND OF THE INVENTION The present invention relates to a data processing input apparatus using two independently rotatable elements for indicating three degrees of freedom of movement.

Trackball input devices are known to include a track¬ ball rotatably supported in a pocket in a base. Two wheels or rollerβ are arranged to contact the outer surface of the trackball and to rotate perpendicular to each other in vertical planes respectively aligned with X and Y axes of the pocket. Rotation of the trackball in either the X or Y directions thuβ causes the respective wheel or roller to rotate as well. Detection of the direction of rotation of the trackball has been effected in various ways, typically through quadrature or biased electrical contacts.

With biased electrical contact detection, pairs of electrical contacts are arranged about the periphery of the wheels or rollers and one of each pair is resiliently biased in a direction to keep the contacts of a pair separated. As the trackball rotates, the contacts are successively pressed against the periphery of the respective wheel or roller in a direction opposite the biasing direction so as to cause the pairs of contacts to touch each other and to complete an electrical circuit. The contacts break this electrical circuit when they are no longer pressed by the trackball. The order in which electrical contact is made indicates the direction in which the trackball has rotated. When detection is effected by quadrature method, a phase shift in light aimed at the rotating wheel or roller is detected.

In one quadrature detection scheme, an interference pattern of circumferentially arranged slots is provided throug faces of a wheel. The slots are made the same size and are separated from each other in succession by vpokes of the same size. Two phototransistorβ are offset from each other and positioned to receive two beams of infrared light as they pass through the slots. When the wheel turns, each transistor produces a square-wave signal which is 90* out of phase from the other. Thus, one square-wave signal precedes the other during rotation of the wheel in the clockwise direction, but trails the other during rotation of the wheel in the counter- clockwise direction. This enables a determination of the direction of rotation of the trackball.

In another quadrature detection scheme, electrically conductive wipers are arranged on a roller or wheel to brush against electrically conductive (e.g., copper) strips on the wheel as the wheel rotates. The strips are spaced apart from each other is a circumferential direction on the wheel so that contact with a wiper is made only when the wiper brushes against the strips; there is sufficient spacing between strips such that the wiper alternates in either making contact with a strip or not making contact. When contact is made, an electri¬ cal circuit is completed.

Multiple wipers are employed (e.g., four wipers arranged so that at most two of the four wipers may complete an electrical circuit at any one time) so that a determination may be made at any given time as to which wipers have successfully completed an electrical circuit and which have not. By comparing this determination with a previously made determina¬ tion regarding which wipers made electrical circuit completion, the direction of rotation may be ascertained. For instance, if the first and second wipers initially made electrical connection but the third has not and then the second and third wipers make electrical connection next but the first no longer does, this may signify clockwise rotation of the wheel. If electrical contact took place in reverse order, this would signify counterclockwise rotation.

In still another quadrature detection scheme, a pattern of alternating reflective and non-reflective stripes are arranged circumferentially about a face of a roller. The reflective stripes may be mirrored and the non-reflective -stripes may be dark to effect light absorption, light is aimed at the stripes and is reflected off the reflective stripes to phototransistors. There are four phototransistors spaced from each other in a line across the path of the reflected light. It is preferable for the phototransistors to be twice as wide as the distance which the reflective stripes extend in the circumferential direction. As the roller rotates, light is reflected off at most a successive two of the reflected stripes and sweeps across the four phototransistors. The direction of rotation of the roller is determined based upon a comparison between which phototran¬ sistors are receiving light and which were receiving light previously. This comparison is made every few milliseconds or so, which is a period of time that is much shorter than is required for the roller to complete a full cycle of stripe rotation in which successive stripes reach the same position relative to the location of the phototransistors as are the stripes which are currently in position for reflecting light. Once the direction of rotation of the trackball is determined from the detected movement of the wheels or rollers aligned with the X or Y axes, the information may be used to control a cursor on a computer screen so as to cause it to move in X and Y directions on the screen in accordance with this determined direction of rotation. This is a fairly accurate way to move a cursor quickly in a desired direction on a computer screen, because the movement is only in the X-Y plane, i.e., only two degrees of freedom in movement is needed. If one desires to effect cursor movement in the Z plane, the prior art has offered some solutions.

SUBSTITUTE SHEET One prior art technique involves adding a Z axis rolle or wheel in contact with the trackball. This Z axis roller rotates with the trackball when it is moved in a direction perpendicular to the X and Y axis rollers or wheels, i.e., in horizontal plane. The direction of rotation of this Z axis roller or wheel is detected in a manner similar to the aforementioned detection schemes or the X and Y axes rollers or wheels, i.e., by the quadrature scheme or the biased electrical contact scheme. The advantage of this configuration is that movement i the X, Y and Z directions may be detected simultaneously. However, it is very difficult for a human to rotate the trackball in a purely horizontal direction without also rotating the trackball even slightly in the X and Y directions. Thus, control of movement in the Z direction is not as accurat as for the X and Y directions.

Another prior art technique provides better accuracy i the control for the Z direction. With this technique the X an Y axes of the trackball are redesignated into X and Z axes or and Y axes at any desired time, e.g. in response to depressing a push button. The same accuracy of control for the X and Y directions will also be provided for the Z and Y or Z and X directions. Unfortunately, such a technique does not enable the simultaneous accurate control in X, Y and Z directions; rather, there is an interruption of the trackball movement to enable realignment for a different set of coordinate axes.

It would be desireable to have an input device which employs a traclcball that can be manipulated to provide accurat control for three degrees of freedom of movement, and thereby simultaneously move a cursor in the X, Y, Z directions. It would also be desirable to effect the manipulation of the input device with only one hand and still have accurate control for all three degrees of freedom of movement. SUMMARY OF THE INVENTION The present invention is directed to an input apparatus which allows for simultaneous accurate control of cursor movement in the X, Y and Z directions, by providing a trackball with a Z axis adjustment ring.

In an illustrative embodiment of the invention, this input apparatus is basically a trackball device having a base, a ball element rotatably supported by -the base and sensors for detecting the direction of rotation of the ball element. According to the invention, a rotary element accessible from the top of the base and rotatable about the ball element is included on the trackball. Further, a sensor for detecting the direction of rotation of the rotary element is added. The rotary and ball elements are positioned in close proximity to each other so as to be rotatable manually with the same hand, either together or independent of each other.

Preferably, the palm of the hand used for rotating the trackball rests against the top surface of the base so that the fingers may accurately rotate the ball and rotary elements. BRIEF DESCRIPTION OF THE DRAWINGS

While the scope of the invention is set forth in the appended claims, a better understanding of the present inven- tion is provided by reference to the following description and accompanying drawings in which:

Fig. 1 shows a top plan view of the input apparatus in accordance with a first embodiment of the present invention; Fig. 2 shows a side elevational view of the device of Fig. 1;

Fig. 3 shows an enlarged cross-sectional view along lines 3-3 of Fig. 1;

Fig. 4 shows an enlargement of a fragmentary bottom view of the encoder ring in the direction of the arrows 4-4 of Fig. 3;

Fig. 5 shows a top plan view as in Fig. 1, except without the trackball in the pocket; ,

Fig 6 shows a top plan view of the input apparatus in accordance with a second embodiment of the present invention. Fig. 7 shows a side elevational view of the device of

Fig. 6; Fig. 8 shows an enlarged cross-sectional view along lines 8-8 of Fig. 6;

Fig. 9 shows en enlarged fragmentary bottom view of the encoder ring in the direction of the arrows 9-9 of Fig. 8; Fig. 10 shows a schematic diagram for the control circuits of the first and second embodiments;

Fig. 11 shows a cross-sectional view of another embodiment similar to Fig. 3;

Fig. 12 shows a view in the direction of arrows 12-12 of Fig. 11, but with the light emitter removed for the sake of clarity;

Fig. 13 shows a cross-section of a joy stick embodiment of the present invention; and

Fig. 14 shows a cross-section of a mouse embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning to the drawings, Figs. 1-5 show that an input device 1 that simultaneously provides accurate X, Y and Z movement indicator signals, e.g., for driving a cursor of a display. The device includes a two-piece housing 2, in trackball 3, push buttons 4, digital interface connection port 5 and encoder ring 9. The trackball 3 is utilized like similar prior devices to provide two degrees of freedom of movement for a cursor along the X and Y coordinate axes. However, the encoder ring 9 is rotatable independent of the ball 3 and enables a third degree of reedom of movement in the Z direc¬ tion, i.e., perpendicular to the X and Y directions. The signals representative of the X, Y and Z movements appear at connection post 5 and may be coupled by suitable cables to a computer system.

As shown in Figs. 3 and 5, the trackball 3 is rotatably supported on bearings or rollers 8A, -8B, 8C which protrude from a support 6.'which forms a pocket. The rollers 8A, 8B, 8C are rotatably supported axially to the printed circuit board 7. When the ball 3 is rotated, the rollers will also rotate to the extent the ball is moved in the direction perpendicular to the axes of the rollers. The rotation of rollers 8A and 8B may be converted in to electrical signals by conventional means. Roller 8C is an idle bearing in that detection of its rotation is not necessary. Pushbuttons 4 may be used to create addi¬ tional electrical signals. For example, they may be used to create marker signals or "ENTER".

The Z direction signal is gained by encoder ring 9, which is rotatable in a plane about the ball 3. In a preferred embodiment shown in cross-section in Fig. 3, the encoder ring 9 is shaped so as to have a portion 13 underneath the housing 2 and a portion 12 resting on the upper edge of support 6.

Further, the encoder ring 9 has a groove 15 accommodating a projection 16 from the support 6. Thus, the encoder ring 9 is rotatably held in position between the housing 2 and support 6, and support 6 forms a support bearing for the encoder ring 9. An extension 14 of the encoder ring 9 protrudes outward away from the housing and is spaced from the ball 3 by the portion 12. The distance between the ball 3 and extension 14 is made small enough that an extension 14 is within reach of the fingers or thumb of an ordinary adult hand with its palm on ball 3. Therefore, the extension 14 may be rotated by the thumb simultaneously with rotation of the ball 3 by the other fingers or palm on the same hand.

The direction of rotation of the encoder ring 9 is detected by an emitter/detector assembly 10 which emits a light beam on the underside of the encoder ring and receives reflected light, if any. One example of the emitter/detector assembly would include a light emitting diode (.LED) 10A as the emitter and a phototransistor detector array 10B as the light receptor. The array may consist of four phototransistors arranged along the line of travel of the light reflected from the bottom of ring 9.

The underside of the encoder ring 9 in the preferred embodiment has a plurality of stripes 18 (Fig. 4), i.e., alternating nonreflective stripes 18B and reflective stripes 18A arranged on the underside in a circumferential direction. The light is preferably absorbed by the nonreflective stripes,

SUBSTITUTE SHEET but is reflected off the reflective stripes to the light receptor array 10B of the emitter/detector assembly 10.

The reflective stripes may be mirrored surfaces and th nonreflective stripes may be dark or angled so as to reflect the light away ro the receptor array 10B of the emit¬ ter/detector assembly 10. If one assumes that even a dark surface will reflect some amount of light, then the light receptors of the emitter/detector assembly 10 need to be responsive only to a threshold of light impinging on its surface which is greater than the amount of light possibly received due to reflection off the dark stripe.

Each time a light receptor (or a phototransistor detector) of the array 10B receives light, a pulse signal is generated. Comparators may be employed to compare pulse signals from the first and third light phototransistors and from the second and fourth phototransistors of the array so as to generate two square-wave signals 90 degrees out of phase with each other. Depending upon which signal precedes or trails the other, the direction of rotation of the rotary element may be determined.

During operation of the input device 1, the base of the palm of the hand is rested on surface 2A of the housing between pushbuttons 4. The thumb is used to rotate the encoder ring 9 and the rest of the ingers or the center of the palm is used to rotate the ball 3. In this manner, accurate control in the X, Y and Z directions is assured, whether the encoder ring is rotated independent of or simultaneously with the ball 3.

The emitter/detector assembly 10 may be secured to the printed circuit board 7, which contains the comparator cir- cuitry shown in Fig. 10. Fig. 10 is typical of the electronics circuitry for any of the embodiments. The principle of operation which is well known for the X and Y axial directions for detecting the direction of rotation of a trackball has been similarly applied in the Z direction for rotation of said encoder ring.

For each of the X, Y and Z axes, there is a correspond¬ ing infrared light emitting diode (LED) 90-92 and quad or phototransistor detector 93-96. The LEDs are exemplified by a Lite On Model LTE-2871 device and the quad detectors are exemplified by Silicon Detector Corp. Model SD-4087.

Quad comparator 96 is in communication with quad detectors 93 and 94 via two respective sets of four data com¬ munication lines. Quad comparator 97 is in communication with quad detector 95 via one set of four data communication lines. Since each quad detector has our light receptors arranged linearly with each receptor being associated with a respective one of the data communication lines, when a light receptor receives light from an associated LED, a pulse signal is transmitted through a respective data communication line to the respective quad comparator.

The quad comparators compare the pulse signals from respective pairs of data communication lines corresponding to the light receptors. These receptors cannot receive light at the same time. That is, as the encoder ring rotates between the LEDs and quad detectors, only two of the light receptors may receive light at any one time as the light seems to-sweep across the quad detectors during rotation in one direction.

The quad detector generated signals which are indicative of the receptors which receive light, are sent to microprocessor 98. The quad comparators are exemplified by Texas Instruments circuit Model TLC3704 and the microprocessor is exemplified by Signetics Model 87C51.

The microprocessor 98 is responsible for counting transitions in the signals and comparing their phase to determine speed and direction. The frequency of the received pulses is indicative of the speed of rotation. The signals generated by the quad comparators may be in binary form (e.g. digital such as O or 1 or analog such as + or - voltages) so that the corresponding one of each pair of light receptors that received the light may be identified. The microprocessor 98 is then responsible for conveying data signals indicative of the speed and direction of rotation to a host computer (not shown) which is interconnected with plug 100 (e.g. at input/output data communication port 5). A serial driver chip 99, exemplified by Texas Instru¬ ment Model TI 74188, provides the necessary handshake signals or enabling RS232 compatibility such as data communication signals DTR (data terminal ready), RTS (ready to send), and RD (read data), and accommodates +5 volt potential and ground GND. The serial driver chip 99 is connected between the plug 100 and microprocessor 98 via data communication lines and power lines. One purpose of the serial driver chip is to avoid burning out the microprocessor. It is also possible to eliminate the quad comparators of Fig. 10 entirely by extending the sets of four data com¬ munication lines directly to the xαicroprocessor 98, which woul contain the necessary programming to accomplish the same functions as the quad comparators. Fig. 10 does not show all the grounds, power supplies, pull up resistors, noise suppression capacitors and clock circuitry for the sake of clarity; such additions are well known rom prior trackball quadrature detection arrangements and are applied in the same manner to the Z-axis electronics components.

The microprocessor 98 is also responsible for polling switches 102, 103, which are the push buttons 4, and conveying their status to the host computer. The push buttons 4 are optional and may be provided to add further features to the input device. For instance, depressing one of the push buttons may result in the instant reorientation of the relative X, Y and Z axes with respect to a new initial reference position or a cursor. The pushbuttons may also provide input independent of positioning a cursor in the X, Y or 2 directions, e.g. ENTER, .as indicated above.

Further, the rotation of the encoder ring 9 need not necessarily result in movement of the cursor in the Z direc¬ tion. Such'rotation may be used as input for other types of computer applications which may or may not be position related, since movement of the encoder ring 9 is independent of the rotation of the track ball.

SUBSTITUTESHEET In addition, the encoder need not form a complete circle around the entire ball 3. Another embodiment would have the encoder 9 as a fragmentary portion of a ring.

Still another variation would be to provide a support surface between the ball 3 and the encoder ring 9. This requires that the portion 12 of the encoder ring 9 be beneath a projecting surface added to the top of the support 6 that extends away from the ball 3. A groove or the like would then be formed in the support 6 and housing 3 to engage with the encoder ring 9. Preferably, the encoder ring 9 is concentric to the center of the ball 3 in the support 6.

Figures 6-9 show another embodiment in which a wall 22 of a housing 30 extends to a support cup 32. It is between an encoder ring 28 and the light emitter 36 so that the ring 28 sits on wall 22 and a top surface 36 of the support cup 32 is visible from the top. The encoder ring 28 is thus freely rotatable within the confines of a groove 38 in the housing 30, which groove is formed by housing 30 where wall 22 begins and where the edge of support cup 32 and a top surface 26 of the support cup 32 is visible from the top of the support cup 32. A window or slot 40 is provided in the wall 22 to enable light from a light emitter 36 to reach and reflect off the reflective stripes 18A on the encoder ring 26 to a detectr assembly 34. The light emitter may be enclosed within an opaque shield 20 so as to allow a narrow light beam to leave only through a small opening 24 in the shield 20 so as to impinge the stripes and reduce stray light from otherwise reflecting off other surfaces and onto the reflective stripes. For the sake of clarity, rollers are not depicted in Fig. 8 but would otherwise be located in the same general location as shown in Fig. 3 for roller 8B. Also, a view analogous to Fig. 5 would also pertain to the embodiment of Figs. 6-9, but has been omitted because it would be largely redundant to Fig. 5 as far as the internal view of the support cup 6 is concerned. Also, the emitter/detector assembly 10 of Fig. 3 is interchangeable with the emitter 36 and detector 34 of Fig. 9.

SUBSTITUTESHEET Figs. 11-12 show a variation of the Fig. 3 embodiment utilizing a different movement detection scheme. Here, an encoder ring 60 has a projecting wall 62 on which interference slits 66 are located spaced apart from each other in successio by the width of one slit. They extend along the entire circum ference of the encoder wall 62. A light emitter 36 is posi¬ tioned perpendicular to wall 62 and is aimed at a detector array 64 so that the light must pass through the slits 66 from the emitter 36 in order to reach the detector array 64. Preferably, a pair of light emitters are aimed at a pair of detectors through the slits. The pair of detectors are arranged offset from each other to create signals with a 90- degree phase shift from each other when receiving light from respective light emitters through the slits. Alternatively, three or four detectors may be used and a comparison made as between which detectors receive light at a point in time and which detectors previously received light. Such a comparison takes place every few milliseconds or so to ensure that successive slits have not yet completed rotation to a full cycle relative to the position of the detectors.

Fig. 13 shows an embodiment of Fig. 1 being employed for a joystick 70 instead of a trackball. The base of the joystick is spherical as is the ball of the trackball; additional detectors are provided in a.known manner (not shown) for detecting changes in torque or displacement. The joystick may be held within a support cup 76. An encoder ring 72, essentially identical to any of the previously mentioned encoder rings, is within a housing 78. The encoder ring 72, in cooperation with an emitter/detector assembly 74 (identical to that of the first embodiment) detects changes in the direction of rotation of the ring with respect to the reflective/non- reflective alternating stripes on the underside of the encoder ring and provides an additional degree of freedom in movement. Fig. 14 shows a mouse embodiment, which has a ball 80, encoder ring 82 identical to any of the other encoder rings, an emitter/detector assembly 84 in a housing 88 and a support cup 86 rotatably holding the ball. The encoder ring 82, in

SUBSTITUTESHEET cooperation with the emitter/detector assembly 84 detects changes in the direction of rotation of the ring with respect to reflective and nonreflective stripes on the underside of encoder ring and provides an additional degree of freedom in movement. As is characteristic of a mouse, a lower portion of the ball 80 is free to roll along a surface.

It is within the scope of the present invention to interchange any component mentioned in one embodiment by a corresponding component in another. Further, any of the systems employed in the prior art for detecting the direction of rotation may be substituted for the detection schemes described in any of the embodiments and in any combination thereof.

While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be understood that various changes and modifications may be made without departing from the spirit and scope of the present invention.

Claims

WHAT IS CLAIMED IS:

1. .An input arrangement for indicating three degrees of freedom of movement, comprising: a housing; a ball element; holding means attached to said housing or rotatably holding said ball element to be accessible from outside said housing; a rotary element rotatably supported between said housing and said holding means and being rotatable about an axis which passes through said holding means, said rotary element being rotatable independent of rotation of the ball element and being rotatable within a single plane, said rotary element being accessible from outside said housing; means for sensing a direction of rotation of said rotary element; and means for generating signals indicative of said direction of rotation of said rotary element.

2. An input arrangement as in claim 1, further comprising means for sensing a direction of rotation of said ball element when rotatably supported by said holding means and for generating signals indicative of said direction of rotation of said ball element.

3. An input arrangement as in claim 1, wherein said sensing means includes light emitting means for emitting light and light receiving means for receiving reflected light, said rotary element having a surface with a plurality of alternating reflective and non-reflective stripes in succession, said light-receiving light means being responsive to light reflected off said reflective stripes after emission from said light emitting means, said light receiving means being nonresponsive to the light which reaches said non-reflective stripes.

4. An input arrangement as in claim 1, wherein said sensing means includes light emitting means for emitting light and light receiving means for receiving light, said rotary element having a plurality of alternating light transmissible and opaque strips in succession, said light receiving means being responsive to light received rom said light emitting means that passes through a respective one of said light tran- smissible strips when said respective one light transmissible strip is at a predetermined position relative to said emitting light means, said light receiving means being blocked from receiving light from said light emitting means when one of said opaque strips that is between said light receiving means and said light emitting means.

5. An input arrangement as in claim 1, wherein said ball element is a sphere and said rotary element is concentric to said sphere.

6. An input arrangement as in claim 5, wherein said rotary element forms a ring that completely encircles said sphere.

7. An input arrangement as in claim 1, wherein said rotary element has an accessible projection extending in a direction away from said housing.

8. An input arrangement as in claim 1, wherein said ball element and said rotary element are within reach of each other so that both may be simultaneously rotated manually with the same hand.

9. An input arrangement as in claim 1, wherein said rotary element rotatably engages with said support and said housing.

10. An input arrangement as in claim 1 , wherein said housing has a plurality of surfaces including a top surface

SUBSTITUTE SHEET from which said rotary element is accessible, said ball element is a sphere accessible from said top surface so that the input arrangement constitutes a trackball data entry device.

11. An input arrangement as in claim 1, wherein said housing has a plurality of surfaces including a top surface from which said rotary element is accessible, said housing having a bottom surface which is opposite said top surface, and said ball element is a sphere accessible from said bottom surface so that the input arrangement constitutes a mouse data entry device.

12. An input arrangement as in claim 1, wherein said housing has a plurality of surfaces including a top surface from which said rotary element is accessible, said ball element being a sphere with a joystick extending therefrom, said joystick being accessible from said top surface so that the input arrangement constitutes a joystick data entry device.

13. An input arrangement as in claim 1, wherein said sensing means employs quadrature light emitter/detectors for detecting a phase shift of light aimed at said rotary element.

14. A method for indicating three degrees of freedom of movement, comprising the steps of: rotatably holding a ball element; rotatably supporting a rotary element in proximity to the ball element so the rotary element is rotatable about an axis which passes through the ball element, said rotary element being rotatable independent of rotation of the ball element and being rotatable within a single plane; sensing a direction of rotation of said rotary element; and generating signals indicative of said direction of rotation of said rotary element.

SUBSTITUTESHEET

15. A method as in claim 14, further comprising the step of sensing a direction of rotation of said ball element and generating signals indicative of said direction of rotation of said ball element.

16. A method as in claim 14, wherein the step of sensing includes emitting light toward a plurality of alternat- ing reflective stripes and non-reflective stripes positioned in succession to each other on the rotary element, receiving light reflected off the reflective stripes, and being nonresponsive with respect to light reaching said non-reflective stripes.

17. A method as in claim 14, wherein the step of sensing includes emitting light at a plurality of alternating light transmissible slits and opaque strips which are in succession to each other on the rotary element and receiving light that passes through the light transmissible strips.

18. A method as in claim 14, wherein the step of sensing includes detecting a phase shift of light arising from an interference pattern on the rotary element.