WO2002071323A1

WO2002071323A1 - A 3d track ball system

Info

Publication number: WO2002071323A1
Application number: PCT/DK2002/000144
Authority: WO
Inventors: Mikkel Hartmann GRØN; Oskar Myhre Broberg; Jesper Bruun Jensen
Original assignee: Dimentor Aps
Priority date: 2001-03-07
Filing date: 2002-03-07
Publication date: 2002-09-12

Abstract

A 3D track ball system comprises a housing defining a bottom wall, and a top wall, the top wall being kept in spaced apart relationship above the bottom wall and defining therebetween an inner space of the housing, a circular aperture of a diameter of 10 - 70 mm being provided in the top wall. The system further includes a track ball of a solid structure or a shell structure and made from a material such as aluminium, steel, plastic, preferably plastic optionally having a high friction surface coating providing a coefficient of surface friction of 0.1 - 1 and defining a diameter constituting no less than 100 % of the diameter of the aperture of the top wall, and a set of three supporting balls rotatably supporting the track balls thereon, which are made of a material such as steel, plastic having a coefficient of surface friction less than the coefficient of surface friction of the track balls, and preferably of more than 0.1 and are mounted and journalled freely rotatably within the housing in positions, in which the tree centres of the three supporting balls are positioned in a plane parallel with the top wall and constituting an equilateral triangle The equilateral triangle being coaxially aligned in relation to the aperture of the top wall the supporting balls are positioned having their centres positioned in relation to the centre of the tracking ball in an orthogonal coordinate system, including three orthogonal coordinate axes. The system further includes a motion detection system including three motion detectors for detecting the motion of a respective ball of the set if three supporting balls along a respective axis of the orthogonal coordinate system, and for generating signals representing the motion of said balls along said respective axes.

Description

A 3D track ball system

The present invention relates in general to the technical fields of track balls, in particular 3D track balls for use in connection with a computer such as a PC or any other computer system or similar apparatus or device.

In a computer system such as a PC, a CPU or main frame is connected to a keyboard, a display unit or screen and also, in most applications, a mouse including a track ball. The mouse is used for positioning a cursor or any other element represented on the display as the mouse is moved on a supporting surface causing a track ball included within the housing of the mouse to rotate, which rotation is detected by means of detectors converting the motion or rotation of the track ball into a detection of a motion in a two-dimensional area represented by the screen or display. A great number of structures have throughout the last decades been suggested for the two-dimensional track balls or two-dimensional cursor moving mouse structures.

In elaborated CAD/CAM systems, in particular 3D CAD/CAM systems, a need for a cursor motion in three dimensions has been realised. In the art, a number of patent publications describe 3D track balls or 3D mouse structures. Examples of prior art 3D mouse structures are described in the following patent applications and patents: US 4, 493,992, US 5,561 ,445, US 5,751 ,275, US 5,854,623, US 5,774,113, US 5,019,809, US 5,784,052, US 5,914,703, US 5,963,197, US 5,999,165, US 6,164,808 and EP 0 729 112. Reference is made to the above US patents and the above US patents are further hereby incorporated in the present specifications by reference.

Another example of the use of track balls is the still growing field of PC entertainment, in particular PC games and in this context, it is contemplated that the more advanced and more elaborated PC games presently being developed, will call for the use of 3D track balls or 3D mouse structures in the future. Although the general principle of detecting the motion of a rotating ball by means of at least three detectors for representing the motion of the track ball in a 3D simulating display system has proven to be useful, the technique calls for certain improvements and refinements for allowing a more accurate precise and reliable positioning in the 3D representing display system. It has been realised that the prior art 3D track balls, in spite of their advantages as compared to conventional 2D track balls are suffering from certain limitations as to accuracy and in particular separation of the detection of the motion of the track ball in the three dimensions X, Y and Z representing the 3D space. Further, the provision of a third detector element as compared to the conventional prior art 2D mouse structures calls for certain improvements as compared to the conventional 2D mouse structures due to the necessity of a further detector element.

Still further, it has been realised that the conventional track ball structure being a 2D or 3D track ball structure or mouse structure, are not entirely satisfactory, as from an operator's point of view, since the track ball included in the prior art structures are normally of a fairly small size on the one hand reducing the accuracy of conversion of the motion of the track ball into the 3D representation for the motion of a cursor in the 3D display system and on the other hand, due the fairly small size of the conventional track ball increases the overall friction of the track ball or mouse structure.

It is an object of the present invention to provide a 3D track ball system in which the drawbacks and limitations of the prior art systems are eliminated and in particular provide an improved 3D track ball system in which the accuracy of detection of the motion of the track ball representing the 3D motion is optimised as compared to the prior art 3D track ball systems.

It is a further object of the present invention to provide a 3D track ball system in which the cross talk between the detection of the motion of the track ball in the 3D representing system is substantially eliminated ensuring that the detection of motion of the track ball representing the motion in one of the dimensions of the 3D display system is not influencing the detection of motion along the other two dimensions of the track ball in 3D display systems.

It is an advantage of the present invention that the track ball system according to the present invention allows, due to its mechanical structure, an easily an highly accurate positioning in the 3D display system in an easily operable and low friction track ball system.

It is a feature of the present invention that the 3D track ball is of a structure in which the journalling of the track ball is sensed as an almost frictionless journalling or a joumalling exhibiting an extremely low friction allowing the user to easily operate and manipulate the track ball without the necessity of utilising an excessive force for moving and positioning the track ball in its intentional position and in doing so, providing the accurate positioning in the 3D display system.

The above objects, the above advantage and the above feature, together with numerous other objects, features and advantages which will be evident from the below detailed description of presently preferred embodiments of the track ball system according to the present invention are, in accordance with the teachings of the present invention obtained by a 3D track ball system comprising: i) a housing defining a bottom wall, and a top wall, the top wall being kept in spaced apart relationship above the bottom wall and defining therebetween an inner space of the housing, a circular aperture of a diameter of 10 - 70 mm being provided in the top wall, ii) a track ball of a solid structure or a shell structure and made from a material such as aluminium, steel, plastic, preferably plastic optionally having a high friction surface coating providing a coefficient of surface friction of 0.1 - 1 and defining a diameter constituting no less than 100% of the diameter of the aperture of the top wall, iii) a set of three supporting balls rotatably supporting the track balls thereon, the supporting balls being made of a material such as steel, plastic having a coefficient of surface friction less than the coefficient of surface friction of the track balls, and preferably of more than 0.1 and being mounted and journalled freely rotatably within the housing in positions, in which the three centres of the three supporting balls are positioned in a plane parallel with the top wall and constituting an equilateral triangle, the equilateral triangle being coaxially aligned in relation to the aperture of the top wall the supporting balls further being positioned having their centres positioned in relation to the centre of the tracking ball in an orthogonal coordinate system, and including three orthogonal coordinate axes, and iv) a motion detection system including three motion detectors for detecting the motion of a respective ball of the set of three supporting balls along a respective axis of the orthogonal coordinate system, and for generating signals representing the motion of the balls along the respective axes.

It is contemplated that the substantial frictionless sense of the 3D track ball system according to the present invention is, provided through two main features, namely on the one hand the particular adaptation of the surface coefficient of the track ball and the supporting balls, as the track ball has a higher coefficient of surface friction than the supporting balls of the set of supporting balls and secondly and most importantly, provided through the geometrical structure established as the three supporting balls are positioned in an orthogonal coordinate system in which the centre of the orthogonal coordinate system is located at the centre of the tracking ball. According to the positioning of the centres of the supporting balls in the above described orthogonal coordinate system, the points of contact between the tracking ball and the three supporting balls are also located in the same orthogonal coordinate system as the points of contact between the supporting balls and the tracking ball are located on the axis of the orthogonal coordinate system.

Further, according to the teachings of the invention, the detectors included in the 3D track ball systems are for providing a maximum elimination of cross talk between the 3D motion detection system arranged in an orthogonal coordinate system providing a maximum spacing between the three detectors as compared to conventional 3D track ball systems in which the motion detectors for generating signals representing the motion of the track ball in the 3D space are positioned close to one another giving origin to a detection of the motion of the track ball which is not entirely satisfactory as to high resolution and elimination of cross talk between the three channels corresponding to the three detectors and representing the 3D motion in the 3D display system.

Preferably, according to the teachings of the present invention, the track ball of the 3D track ball system is a track ball having a large outer diameter allowing the track ball to be freely accessible by the person operating the track ball system by the palm of the operator's hand as the major part of the track ball of the track ball system according to the present invention is freely exposed and accessible, since the major part of the track ball is positioned freely above the housing of the 3D track ball system.

According to the presently preferred embodiment of the 3D track ball system according to the present invention, the diameter of the circular aperture is 10 - 50 mm, e.g. 20 - 45 mm or 30 - 40 mm, or alternatively a diameter of 10 - 20 mm, 20 - 30 mm, 30 - 40 mm, 40 - 50 mm, 50 - 60 mm or 60 -70 mm, preferably approximately 40 mm, the coefficient of surface friction of the track ball is preferably 0.1 - 0.5, preferably 0.4 - 0.5 or alternatively 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.5; 0.5 - 0.6; 0.6 - 0.7; 0.7 - 0.8 or 0.8 - 0.9, the diameter of the track ball is preferably 100%-200%, preferably 120%-150%, or 100%-110%; 110%-120%; 120%-130%; 130%-140%; 140%-150%; 150%-160%; 160%-170%; 170%-180%; 180%-190%, or

190%-200%, the coefficient of surface friction of the supporting balls is preferably 0.1 - 0.4, preferably 0.2 or alternatively 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.5; 0.5 - 0.6; 0.6 - 0.7; 0.7 - 0.8 or 0.8 - 0.9, and the supporting balls each preferably has a diameter of 8 -20 mm, such as 8 - 14 mm, e.g. 10 - 12 mm, or alternatively 8 - 10 mm, 10 - 12 mm, 12 - 14 mm, 14 - 16 mm, 16 - 18 mm, or 18 - 20 mm. It is believed that the provision of the supporting balls having diameters of the above range contributes to the provision of the above described substantially frictionless journalling of the track ball in the 3D track ball system. In this context, it is preferred that the track ball is preferably made from ABS, POM, PE, PP and optionally having a solid core and preferably having an outer rubber surface coating, such as a natural rubber surface coating or silicone rubber surface coating. According to the presently preferred embodiment of the 3D track ball system according to the present invention, the motion detection system includes separate motion transmission rollers for the transmission of the motion of a respective ball of the three supporting balls to a motion detector for the detection of a signal representing the motion of the respective ball along its respective axis of the orthogonal coordinate system. Although the above described presently preferred embodiment of the 3D track ball includes a set of motion transmission rollers including three motion transmission rollers, the present invention is by no means limited to the above embodiment as the detection system may be implemented without the provision of the motion transmission rollers or be implemented including different kinds of motion transmission elements such as motion transmission balls, motions transmission belts etc..

The rollers of the above described transmission roller system included in the above described presently preferred embodiment of the 3D track ball system according to the present invention, it is preferred that the rollers having a coefficient of surface friction higher than the coefficient of surface friction of each of the supporting balls of the set of three supporting balls and further preferably having a coefficient of surface friction substantially equal to the coefficient of surface friction of the track ball.. Through the provision of the rollers, each having a coefficient of surface friction higher than the coefficient of surface friction of each of the supporting balls and preferably equal to the coefficient of surface friction of the track ball, the above described frictionless journalling of the track ball of the 3D track ball system according to the present invention is further improved and refined.

For providing a maximum sensitivity of the motion detection system, it is preferred that the rollers of the three motion transmission rollers having an outer diameter smaller than the outer diameter of each of the balls of the set of three supporting balls and having an outer diameter of the order of 1 - 10 mm, such as 1 - 2 mm, 2 - 3 mm, 3 - 4 mm, 4 - 5 mm, 4 - 5 mm, 5 - 6 mm, 6 - 7 mm, 7 - 8 mm, 8 - 9 mm, or 9 - 10 mm. As will be readily understood, the smaller diameter of each of the rollers as compared to the outer diameter of each of the supporting balls provides a gear ratio between the supporting balls and the rollers larger than 1 and in doing so, transforms any rotational motion of a respective ball of the three supporting balls to a corresponding rotational motion in the opposite direction of the corresponding roller, however of a rotational velocity higher than the rotational velocity of the supporting ball in question.

In the above described presently preferred embodiment of the 3D track ball system according to the present invention including the above described motion transmission rollers, the motion transmission rollers also preferably constitute an orthogonal system as the axes of rotation of the three motion transmission rollers defining themselves an orthogonal coordinate system having its centre at the centre of the track ball.

The 3D track ball system according to the present invention may include a motion detector system based on any conventional detector technique including optical detection, magnetic, capacitive or inductive detection or even resistive detection principles. Consequently, the motion detectors of the 3D track ball system according to the present invention may, according to alternative embodiments include an optical detector, a capacitive detector or an inductive detector. For the detection of the motion of the 3D track ball system, each of the motion detectors including an optical detector, a capacitive or inductive detector for the detection of the motion of its respective ball along its respective axis of the orthogonal coordinate system and generating a signal representing the position of the ball in question or alternatively the velocity of the ball in question.

In the 3D track ball system according to the present invention, the optical detector principal is preferably utilised for providing a highly accurate detection of the motion of the track ball. The motion detectors preferably include, in accordance with the presently preferred embodiment of the 3D track ball system, slotted wheels as each of the motion detectors preferably includes a slotted wheel journalled on the axis of the rotational roller and chopping the light from a light source such as a LED as the light path from the light source is directed to a light detector such as a photo diode. Alternatively, the motion detectors based on the optical detector principals may be provided included differently configurated light transmission elements such as light transmission elements based on lens systems, fibre optic elements etc., which elements or structures are well known in the art per se.

The motion detection may further, according to the teachings of the present invention be improved or refined through the usage of two LED's or a single LED having a pair of fibre optic elements defining an optical structure similar to the structure including two separate LED's for each of the motion detectors as the provision of two LED's allows for the detection of and a discrimination between the transmission and a non-transmission of light through a slot of the slotted wheel while the transmission of light from the other LED is interrupted by the slotted wheel, the LEDs preferably being IR LEDs, and the photo diode preferably being an IR sensitive photo diode. In greater details, the motion detectors each preferably include two LED's, one for the transmission of light through a slot of the slotted wheel, while the transmission of light from the other LED is interrupted.

The processing of the signals generated by the photo diode of the motion detectors may be based on any relevant signal processing technique including filtering technique, amplification, AD or DA conversion etc. Irrespective of the actual technique of processing the signals generated by the three photo diodes of the motion detectors of the 3D track ball system according to the present invention, Schmitt triggers are preferably included for the shaping of the pulses detected by the photo detector diodes allowing the signal processing to be carried out based on high slope pulses generated by the Schmitt triggers.

The invention is now to be further described with reference to the drawings in which: Fig. 1 is an overall schematic view the structure of the 3D track ball system according to the present invention including a supporting ball and a mounting cup, Fig. 2 is a schematic view illustrating the journalling of the track ball on three roller balls constituting an orthogonal supporting system and also an orthogonal detector system,

Fig. 3 is a perspective view further representing the orthogonal journalling of the track ball in the orthogonal detector system, Fig. 4 is a schematic view illustrating the transmission of motion of the track ball to a single motion transmission track ball of the motion detection system, Fig. 5 is a schematic view illustrating the transmission of motion of the track ball by means of the motion transmission balls, Fig. 6 is an overall diagrammatic view of the electronic circuitry of the motion detection system of the 3D track ball system according to the present invention, Fig. 7 is an overall schematic and perspective view of a prototype implementation of the 3D track ball system according to the present invention, Figs. 8a, 8b and 8c are overall schematic and perspective views of a further embodiment of the 3D trackball system according to the present invention, and

Fig. 9 is an overall diagramatic view of the electronic circuitry of the motion detection system of the further embodiment of the 3D trackball system according to the present invention shown in Figs. 8a, 8b and 8c.

A first embodiment of a 3D track ball system according to the present invention is in general composed of three main elements: An operating ball 1 , three supporting balls 2 and three sensors 3.

The mechanical concept is best described as follows: The operating ball 1 is placed upon three supporting balls 2, shown in Figs. 2 and 3, which make the operating ball 1 fully supported. Each of the supporting balls 2 are positioned in direct contact with a stationary sensor 3 shown in Fig. 5 and are further positioned in an orthogonal detection system in which each of the three sensors 3 detect the motion of its respective supporting ball 2 along one of the three axes of the orthogonal detection system. Every movement of the operating ball 1 effects the supporting balls 2 and results in a rotation of the supporting balls 2. This means that the sensors 3 connected to the supporting balls 2 will rotate and register the movement of the operating ball 1. In short, a rotation of the operating ball 1 results in a rotation of the supporting balls 2, which again results in a rotation of each of the sensors 3. This means that every movement of the operating ball will be detected by each of the three sensors. The operating ball 1 and its design is ergonomic, comfortable and attractive. These factors are the foundation for the specific ball's dimensions, material, etc. The dimension of the operating ball 1 is preferably between 40 - 150 mm in diameter and the operating ball 1 is preferably made of a soft plastic type with a relatively high surface friction. The reasons for these choices have partly to do with the way the operating ball 1 is supported and will be explained later.

Each of the supporting balls 2 are mounted in a cup support 4 shown in Fig. 1. The cup support 4 provides three degrees of freedom for its respective supporting ball. Consequently, each of the supporting balls 2 are allowed to rotate without allowing the supporting balls to be moved in any motion deviating from rotational motion.

The three supporting balls 2 are placed in such a way that they all together are able to interpret the movement of the operating ball 1 in 3 dimensions. This is done by placing each of the supporting balls 2 with their individual centre axis extending through the operating ball's centre point. At the same time the supporting balls 2 are placed in an orthogonal detection system in which each of the ball's centre axis define an angle of 90 degrees with the other supporting ball's outer axes. The concept is best described by considering the operation ball as a 3D coordinate system in which the centre of the coordinate system is positioned in the centre of the operating ball. At the points where the 3 coordinate axes intersect the sphere of the operating ball 1 , the supporting balls 2 are placed in such a way that their individual centre axis are co-linear with the respective coordinate axis.

The operating ball 1 is placed freely on top of the three supporting balls 2. The supporting balls 2 are levelled in the set-up and, due to gravity the operating ball is supported equally of the three supporting balls 2. The levelling of the supporting balls 2 is provided by rotating the 3D coordinate system with the intersection of the graphic axes placed in the middle of the operating ball 1 , 45 degrees around two of the existing axes. Fig. 3 illustrates how the supporting balls 2 are placed compared to the operating ball 1. At the same time the coordinate system is rotated around the Z- and the X-axes. As shown in Fig. 3 the levelling of the supporting balls 2 will have the effect that the operating ball 1 will be covered less than 50% by the set-up. The users of the 3D track ball system will thereby get a larger working surface which will make the 3D track ball system more usable.

Each of the supporting balls 2 are mounted in the above described cup support or fixture which keep them correctly placed relating to the operating ball 1. Viewed from above, the supporting balls 2 are placed in a circle with 120 degrees between them and each of the supporting balls 2 defining an angle of 45 degrees to the base.

The supporting balls 2 and the bearing which they are mounted in is made from a material which has a desirable surface friction in such a way that the friction between the operating ball and the supporting balls, the supporting balls and sensors, and the supporting balls and the bearings are optimal.

To get the correct readings on the ball quality it is mandatory that the sensors 3 are positioned correctly for providing the correct transformation of the motion of the operating ball into the three motional components defined by the axes of the motion detection. Furthermore, it is mandatory that the sensors 3 are placed correctly relative to the supporting balls 2. The supporting balls 2 are to be placed in such a way that they give as little resistance to the movement of the operating ball 1 as possible, and thereby to the movement of the balls themselves. This is done by making sure that each of the supporting balls 2 is not allowed to rotate in the longitudinal direction of the respective sensor in which direction it is not able to rotate.

Each of the supporting balls 2 are basically only affected by rotation of the operating ball 1 around two axes, as is shown in Fig. 4, while the third axis of movement is aligned with one of the spinning axes of one of the sensors 3 and there will be no movement transferred because there is only one contact point between the two objects, namely the supporting balls 2 and the sensors 3. Provided that the sensors 3 are positioned correctly it will be the same case with the relations between the sensors 3 and the supporting balls 2, except that the supporting balls 2 will only rotate around two and only affect the sensor around one, as is shown in Figs. 4 and 5. Fig. 5 shows one way of placing the sensors 3.

A clockwise rotation of the operating ball 1 around the Z-axis will result in a counter clockwise rotation around the Z-axis of the supporting ball 2 placed beneath the operating ball 1. This rotation will not cause the sensor contacted with this supporting ball 2 to rotate. The reason for this is that the supporting ball 2 is rotating around an axis extending through its own centre and the contact point between the supporting ball 2 and the sensor 3. The sensors that are used for the construction of the prototype were chosen having a smooth contact surface and were made of steel, which makes it difficult to transmit movement from the supporting ball to the sensor on the basis of the low coefficient of friction between the surfaces. This problem is avoided by giving the sensor a rubber surface.

Electrical design

In the following, the functionality of the prototype electronics of the 3D track ball system will be described.

Data collection/Sensors The sensors 3 consist of a slotted wheel 5 with a shaft 6 in contact with the ball 3. When the supporting ball 2 rolls it makes the shaft rotate which then makes the wheel 5 rotate. On one side of the wheel two LEDs, not shown in the drawings, are mounted which LEDs emit light through the slots of the wheel. On the opposite side two photosensitive diodes 7 are placed. These diodes 7 receive the light from the LED's. When the wheel turns the light transmitted to the diodes will pulse. The reason two diodes are needed is that otherwise the direction of the rotation can not be found. In order to do this, the diodes are placed so that when one of them receives light, the other will not receive light.

Schmitt trigger

Type 74hc14

Since the pulses generated by the photosensitive diodes are soft wave shaped, the pulses need to be transformed into sharp edged pulses to perform the counting. The pulses from the sensors are passed through a set of Schmitt triggers to generate square pulses. The Schmitt triggers chosen invert the signal, but this has no effect on the measurement because only the flanks are needed for counting.

Positive edge Flip-flop

Type MM74hc74AN

To detect which way the wheel is turning a positive edge flip-flop is used. The two pulse signals from the sensors are entered into the flip-flop. One pulse is used to trigger the flip-flop while the other is used for comparison. When the flip-flop receives a flank from the trigger pulse it checks the state of the other signal. If the signal is low it returns a low signal and if it is high, a high signal is returned.

Counter

Type MM74hc4040 The pulses from one of the sensors are routed to a counter chip. The counter counts the number of pulses received. The counter has 12-bit accuracy but only 7 of these are used. This allows a total of 128 pulses to be counted. The counter is reset after each sample so the 128 counts are sufficient.

Latch

Type MM74hc374N

The latch collect 7 bit from the counter and the direction bit from the flip-flop. This is done once per sample. The function of the latch is to lock the data while they are being read by a UART, vide below, i.e. a universal asynchronous receiver- transmitter conventionally used in a computer for the handling of asynchronous serial communication. The latch is also used to direct the sequence in which the data from the sensors is being sent to the UART.

UART

Type HD6402

The UART translates the input signal from the latches into a serial signal that can be transferred to the computer. Internally the UART has a latch to ensure that the input data is not changed while it is being sent. The UART must be reset upon startup to clear the registers. This is done by a power on signal which is generated when the circuit is turned on.

Line driver

Type MAX232ACPE

The line driver takes the signal from the UART and ensures that it is sent in the right format.

Crystal oscillator

Type MMx363a

A crystal oscillator generates a frequency used for timing of the circuit.

Frequency splitters Type MM74hc4040

The frequency generated by the crystal oscillator is to high to be used directly to time the sampling rate of the UART. Therefore a counter is introduced as a frequency splitter. The use of the counter has the benefit that several different sampling rates can be obtained. The frequency used to control the UART is, however, too high to control the sequence in which the data is sent to the UART. To correct this, another counter is introduced. The output from this counter is 12 bits, out of which three is selected using a patch. These three bit can then be used to control the sequence.

Sequencer

Type MM74hc138

The sequencer is used to control sequence in which the data is sent to the UART. The frequency is determined by the three bits, mentioned above. Depending on the bit pattern fed to it, the sequencer will choose which data to send.

The signal from the sequencer is used to:

Signal the UART to send. The signal is collected through a NAND gate.

Signal a specific latch to collect its data or become transparent. Reset a specific counter.

The sequencer points to 8 registers of which only three are used. This provides a short time delay, which enables the detection of the start of the sequence.

Driver software

Input to the driver software is delivered from the orientation device through a serial port. The input consists of one byte per sensor, sequently divided with one byte per sample.

The serial port is read with the function READFILE. This function has an internal buffer to ensure that there is no loss of data even if the system is busy when the data arrives. The output from the function is the counted pulses from a specific sensor. The pulses from the three sensors are then translated into angles around the three local axes (x', y', z') of the sensors. This is done simply by multiplying with a correction factor. These angles are then further translated into angles around the global axis (x, y, z). This is done by rotation of the local coordinate system to align with the global coordinate system, with a 4 by 4 matrix multiplication.

Viewer software

This viewer software is based on a Direct3D example program from Microsoft. The program allows the user to rotate a 3D object using our orientation device.

List of electrical and electronic components of the diagram illustrated in Fig. 6 and used in the prototype embodiment of the 3D track ball system, also shown in Fig. 7:

Element description of the prototype of the 3D track ball system:

The first prototype of the 3D track ball system consisted of 21 elements.

In Figs. 8a, 8b and 8c, a further embodiment of the 3D track ball system according to the present invention is shown based on the orthogonal motion detection system. In Figs. 8a - 8c, components or elements identical to components or elements described above are designated the same reference numeral as used above, whereas components or elements corresponding to previously described components or elements, respectively, and serving the same purpose as the previously described components or elements, however, differing in shape or otherwise from the previously described components, respectively, are designated the same integer as previously used, however added a marking for identifying the difference. In Figs. 8a, 8b and 8c, the support cup 4' for supporting the supporting balls 2 are shown constituted by a block providing the intentional geometrical orientation of the axis 6' of the tooth wheel 5' co-operating with an integrated optical sensor or detector 3' including an LED and a photo diode positioned on opposite sides of slot into which the slotted wheel 5' protrudes. The tooth wheel 5' differs from the above- described tooth wheel 5' in that the teeth of the tooth wheel 5' are turned into an angle for allowing the integrated optical sensor to be readily mounted parallel with the supporting cup or block 4' on a supporting surface without necessitating the use of specially configurated supports for the supporting of the optical sensor 3'.

In Fig. 9, the electronic circuitry of the further embodiment of the 3D track ball system shown in Figs. 8a - 8c is presented. The components illustrated in the diagram in Fig. 9 are included in the below list of electrical and electronic components of the diagram illustrated in Fig. 9 and used in the further embodiment of the 3D track ball system also shown in Figs. 8a - 8c.

Although the present invention has above been described with reference to two specific embodiments of the 3D track ball system, which embodiments have been implemented by the inventors, the present invention is by no means to be construed limited to the above described embodiments, as the invention is to be construed in the true understanding of the wording of the appending claims also including modifications and alternatives obvious to a person having ordinary skill in the art. Such modifications or alternatives are therefore also to be considered part of the present invention.

Claims

1. A 3D track ball system comprising: i) a housing defining a bottom wall, and a top wall, said top wall being kept in spaced apart relationship above said bottom wall and defining therebetween an inner space of said housing, a circular aperture of a diameter of 10 - 70 mm being provided in said top wall, ii) a track ball of a solid structure or a shell structure and made from a material such as aluminium, steel, plastic, preferably plastic optionally having a high friction surface coating providing a coefficient of surface friction of 0.1 - 1 and defining a diameter constituting no less than 100%) of said diameter of said aperture of said top wall, iii) a set of three supporting balls rotatably supporting said track balls thereon, said supporting balls being made of a material such as steel, plastic having a coefficient of surface friction less than the coefficient of surface friction of said track balls, and preferably of more than 0.1 and being mounted and journalled freely rotatably within said housing in positions, in which the three centres of the three supporting balls are positioned in a plane parallel with said top wall and constituting an equilateral triangle, said equilateral triangle being coaxially aligned in relation to said aperture of said top wall said supporting balls further being positioned having their centres positioned in relation to the centre of said tracking ball in an orthogonal coordinate system, and including three orthogonal coordinate axes, and iv) a motion detection system including three motion detectors for detecting the motion of a respective ball of said set of three supporting balls along a respective axis of said orthogonal coordinate system, and for generating signals representing the motion of said balls along said respective axes.

2. The 3D track ball system according to claim 1 , said diameter of said circular aperture being 10 - 50 mm, e.g. 20 - 45 mm or 30 - 40 mm, or alternatively a diameter of 10 - 20 mm, 20 - 30 mm, 30 - 40 mm, 40 - 50 mm, 50 - 60 mm or 60 -70 mm, preferably approximately 40 mm, said coefficient of surface friction of said track ball being 0.1 - 0.5, preferably 0.4 - 0.5 or alternatively 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.5; 0.5 - 0.6; 0.6 - 0.7; 0.7 - 0.8 or 0.8 - 0.9, said diameter of said track ball being 100%-200%, preferably 120%-150%, or 100%-110%; 110%-120%; 120%- 130%; 130%-140%; 140%-150%; 150%-160%; 160%-170%; 170%-180%; 180%- 190%, or 190%-200%, said coefficient of surface friction of said supporting balls being 0.1 - 0.4, preferably 0.2 or alternatively 0.1 - 0.2; 0.2 - 0.3; 0.3 - 0.4; 0.4 - 0.5; 0.5 - 0.6; 0.6 - 0.7; 0.7 - 0.8 or 0.8 - 0.9, said balls each having a diameter of 8 -20 mm, such as 8 - 14 mm, e.g. 10 - 12 mm, or alternatively 8 - 10 mm, 10 - 12 mm, 12 - 14 mm, 14 - 16 mm, 16 - 18 mm, or 18 - 20 mm.

3. The 3D track ball system according to any of the claims 1 or 2, said track ball being made from ABS, POM, PE, PP and optionally having a solid core and preferably having an outer rubber surface coating, such as a natural rubber surface coating or silicone rubber surface coating.

4. The 3D track ball system according to any of the claims 1 - 3, said motion detection system including three motion transmission rollers for the transmission of the motion of a respective ball of said set of three supporting balls to a motion detector for the detection of a signal representing the motion of the respective ball along its respective axis of said orthogonal coordinate system.

5. The 3D track ball system according to claim 4, each of said rollers having a coefficient of surface friction higher than the coefficient of surface friction of each of said supporting balls of said set of three supporting balls and further preferably having a coefficient of surface friction substantially equal to the coefficient of surface friction of said track ball.

6. The 3D track ball system according to any of the claims 4 or 5, each of said rollers of said three motion transmission rollers having an outer diameter smaller than the outer diameter of each of said balls of said set of three supporting balls and having an outer diameter of the order of 1 - 10 mm, such as 1 - 2 mm, 2 - 3 mm, 3 - 4 mm, 4 - 5 mm, 4 - 5 mm, 5 - 6 mm, 6 - 7 mm, 7 - 8 mm, 8 - 9 mm, or 9 - 10 mm.

7. The 3D track ball system according to any of the claims 4 - 6, the axis of rotation of said three motion transmission rollers defining themselves an orthogonal coordinate system having its centre at the centre of said track ball.

8. The 3D track ball system according to any of the claims 1-7, each of said motion detectors including an optical detector, a magnetic, capacitive or inductive detector for the detection of the motion of its respective ball along its respective axis of said orthogonal coordinate system defined by said set of supporting balls and generating a signal representing the position of the ball in question or alternatively the velocity of the ball in question.

9. The 3D track ball system according to any of claims 4 - 8, each of said motion detectors including a slotted wheel journalled on the axis of said rotational roller and chopping the light from a light source such as a LED as the light path from the light source is directed to a light detector such as a photo diode.

10. The 3D track ball system according to claim 9, the motion detectors each including two LEDs, one for the transmission of light through a slot of the slotted wheel while the transmission of light from the other LED is interrupted by the slotted wheel, said LEDs preferably being IR LEDs, and said photo diode preferably being an IR sensitive photo diode.

11. The 3D track ball system according to claim 10, further including Schmitt triggers for the shaping of the pulses detected by the photo detector diodes.