WO1999008229A2

WO1999008229A2 - Cursor control device with separate one-dimensional optical grids

Info

Publication number: WO1999008229A2
Application number: PCT/NO1998/000233
Authority: WO
Inventors: Steinar Pedersen
Original assignee: Steinar Pedersen
Priority date: 1997-08-12
Filing date: 1998-08-07
Publication date: 1999-02-18
Also published as: WO1999008229A3; NO973691L; NO973691D0; NO305147B1

Abstract

A device for positioning and control of computer cursors and other objects is described, where the device's control module comprise a stick (2) that is attached to a guide plate (3) which is freely movable in the X-Y plane; where the movement of the control module is detected by means of a sensor system that utilises laser beams or other forms of narrowly focused light and a reflector plane that on its surface contains non-overlapping grids consisting of non-reflecting stripes, in addition to photosensors that can detect reflected light pulses when the laser beams traverse the grids.

Description

Cursor Control Device with Separate One-dimensional Optical Grids

The described invention constitutes a device that can be used to move and control PC cursors and other virtual and physical objects in two or three dimensions, and is based upon the use of an opto-electronic sensor system utilising laser beams or other narrowly focused light and a reflector plane that on its surface contains two or more grids consisting of parallel, non-reflecting stripes .

The most popular devices used for control of cursors and other graphical symbols on the PC screen are the mouse, the trackball, the trackpoint and the joystick.

The first electro-mechanical mouse described in U.S. Pat. 3,541,541 was developed at Stanford Research Institute. This mouse utilised a pair of wheels that rotated potentiometers and transformed X- and Y-movement into analogue signals. Further development of the mouse concept lead to the utilisation of a ball instead of two wheels, providing a more uniform tracking movement.

In modern varieties of the mouse, the ball rotates shafts that are engaged to two circular, rotating disks with radial oriented apertures, which upon movement of the mouse provide pulse-formed position signals to the monitor (U.S. Pat. 3,892,963; 3,541,521 and 4,464,652).

The mouse being described in U.S. Pat. 4,409,479 utilises an alternative optical detection principle. The mouse incorporates light sources and photosensors, and when the mouse is moved across the surface of a reflecting plate with a non-reflecting grid pattern, the reflected light pulses will provide information about direction and speed of movement .

An alternative system used for optical tracking is described in U.S. Pat. 5,288,993 where the control device incorporates a ball containing an irregular pattern on the surface, which is reflected onto a photosensor grid by means of diffuse light.

Mice and trackballs are operated by use of hand and thumb, respectively, of which none are especially trained for precise motion control. Other systems utilise index finger control or incorporate a stick that is gripped by fingers or hand and therefore exhibit better precision (U.S. Pat. 4,736,191; U.S. Pat. 4,680,577;

PCT/US89/05662; EP A3 0,295,368; EP Al 0,640,937; U.S. Pat. 4,719,455; PCT/JP89/01148; PCT/CA90/00022 ; U.S. Pat. 4,935,728; EP A3 0,556,936).

A particular limitation associated with many of the devices previously described is that the degree of precision is limited compared to the precision and calculating powers of modern computers. An important reason for this lack of precision is that the devices are not easily handled, and do not fully utilise the fine motor capabilities of the human musculature, and in addition that many of the detector systems used are not particularly sensitive or precise. Several devices are furthermore based upon very complicated mechanical constructions being costly to produce.

This inventor has developed control devices as earlier described in PCT/NO94/00113 , in Norwegian patent 300943 and in PCT/NO96/00077 where the central control module comprises a finger-grip (control stick) that is attached to a plate (guide plate) , and which utilise several different sensor systems. Devices based upon the stick- and-plate configuration satisfies many of the ideal requirements of a cursor control device, as they may be handled according to a writing or drawing motion and thereby utilise the precise motor abilities of the hand, thumb and index finger in combination.

However, control devices described in PCT/NO94/00113 do not fully realise all the control options inherent in the stick-and-plate configuration. This potential is used more fully with devices described in Norwegian patent 300943 and in PCT/NO96/00077 , which instead of utilising the movement of the control modules to generate a tracking signal employ a system for assessment of posi tion or spatial configuration of the control modules, making the device better suited e.g. for three- dimensional object control.

The optical mouse (U.S. Pat. 4,409,479) employs a tracking system that incorporates a reflecting plate with two superimposed, orthogonal X- and Y-grids made up of non-reflecting stripes, thereby creating a chequered reflecting pattern. This arrangement puts a heavy demand on the geometry and dimensions of the photosensors, and requires the use of minimum two sensors per axis for assessment of direction of movement.

An alternative to using reflecting grids is to employ masks that allow penetration of light . Such arrangements may also create interference patterns (Moire patterns) that can be utilised for increasing the sensitivity of the detector. Such systems are e.g. described in EP A3 0,556,936. The use of chequered grid patterns and masks put heavy demands on geometry and tolerances, and therefore also strict limitations on downscaling and on the systems' sensitivity.

This inventor has surprisingly discovered that the stick- and-plate configuration provides opportunities for avoiding the limitations of the optical mouse's sensor system. Instead of using a chequered grid pattern on the reflector plane, the stick-and-plate permits the application of two non-overlapping groups of parallel, non-reflecting stripes, constituting two separate grids. The stripes of the two grids are arranged at right angles relative to each other when they are used for motion control in the X-Y plane (2D control) . One may optionally incorporate more reflector planes and grids in order to detect Z-movement and rotation around axes for 3D applications .

This plain grid layout provides opportunities for using sets of very narrow stripes, enabling high resolution, extreme sensitivity and opportunities for miniaturisation, in addition to simple photosensor construction.

Furthermore, the replacement of a chequered grid pattern with two or more stripe grids gives the surprising result that by arranging non-reflecting stripes and their reflecting intervals in a particular way, this allows determination of the control modules' direction of movement by means of only one photosensor per axis . This can not be achieved with chequered grid patterns .

The stripe grids may be created by laser engraving, magneto-polarisation or by deposition of a light absorbing material (e.g. by photo masking) in the form of parallel stripes on the surface of a reflecting surface. Displacement of the control modules is detected by means of laser beams emitted by diode lasers. Other forms of directed, concentrated light beams or other electromagnetic radiation may also be used. For simplicity, the expression laser beam is used in the following when referring to such radiation.

Each time a control module is moved, laser beams will traverse the stripe sets on the reflection plane and cause the formation of reflected light pulses. The number of pulses and the speed of their formation are representative of the speed, direction and extension of module movement .

According to the present invention, a control device is described that encompasses a finger-grip (control stick) which is mounted on a plate member (guide plate) . Both members are representing the control module of the device. The control stick has generally a cylindrical form with a diameter of 3-50 mm and a height of 5-150 mm. It is advantageously sculptured and covered with a rubber-like material for optimum handling comfort. The stick may be vertically erected on the plate, or slightly inclined in order to provide ergonomic advantages (i.e. similar to the position of a pen during a writing movement) . The guide plate is limited in its movement to a defined area of the plane, equivalent to a circle with a diameter of 5-200 mm (the motion range) . The area may have an arbitrary form, but it is advantageously rectangular or square with rounded corners, or circular. The plate is defined to be in its "normal" position when the stick is localised in the centre of the motion range.

The stick may be flexibly mounted on the guide plate, which permits a simultaneous movement of the two control modules relative to stationary parts of the device, and at the same time allows the stick to be displaced relative to the guide plate. In such circumstances the device may be equipped with flexible parts (flexible collars, springs, pneumatic devices, etc.) which can automatically bring the stick back to a normal, preferred position relative to the plate unless it is exposed to a directionally applied force.

Other utilities may also be incorporated that allow the user to sense when the stick attains its normal position. The device may also incorporate an analytical utility (discriminator) , which prevents the control modules to initiate cursor or object movements unless the position changes have passed a certain threshold value relative to the normal position.

The signal generating system (the sensor system) incorporates one or more light sources, e.g. diode lasers that are directed towards one or more reflector planes . The light beams hit the grid areas and are there being reflected in the form of discrete light pulses when the control modules are moved. Photosensors detect these reflections and the signals generated by these are used for control of screen cursors or other objects.

The stick-and-plate configuration and the opto-electronic sensor system described herein may very well be combined with stress- or pressure-sensors for isometric movement control. The use of stress sensors is e.g. described in this inventor's PCT/NO94/00113 and in U.S. Pat. 4,680,577. Such stress sensors may be associated with the control stick, and will generate signals signifying direction and speed of movement when the stick is exposed to a directional force. Such stress sensors may also be associated with the guide plate or other parts of the device, and provide for extra signal generation in addition to the optical system. It is advantageous to localise the stress- or pressure- sensors in a way that allow them to be activated when an attempt is made to move the control modules beyond their normal motion range. In this way, the stress-generated signals may be used to extend a movement that would otherwise be limited by the control modules' motion boundaries. Stress-generated signals may also be used to rotate objects or to transpose the frame of reference (scrolling) .

Preferred embodiments will now be described by means of examples with reference to accompanying figures, where:

Fig. 1 shows a perspective drawing of the two control modules utilised by the invention.

Fig. 2 shows a perspective drawing of the control modules when incorporated in a computer chassis or in a separate control unit .

Fig. 3 shows the control device when incorporated in a portable computer.

Fig. 4 shows a vertical section of the control device according to a preferred embodiment of the invention.

Fig. 5 shows a reflector plate with two sets of circular grids (stripe grids) .

Fig. 6 shows an employed arrangement of light source (diode laser) , optics and photosensor.

Fig. 7 shows an alternative arrangement of diode laser and optics, employing two photosensors.

Fig. 8 shows a section of a stripe grid where the reflecting and non-reflecting stripes are of unequal width, and signals generated by two photosensors when light beams are traversing the grid in opposite directions .

Fig. 9 shows a section of a stripe grid where reflecting and non-reflecting stripes are of unequal width, and signals generated by one photosensor when light beams are traversing the grid in opposite directions.

Fig. 10 shows a section of a stripe grid where reflecting stripes have unequal, and non-reflecting stripes have equal width, and signals generated by a photosensor when light beams are traversing the grid in opposite directions .

Fig. 11 shows a section of a stripe grid where reflecting and non-reflecting stripes have equal width but where the reflecting stripes show unequal degree of reflectivity, and signals generated by a photosensor when light beams are traversing the grid in opposite directions.

Fig. 12 shows an alternative arrangement of light source, photosensor and reflector plane with grids .

Fig. 13 shows the use of stress-sensors connected to the control stick together with the opto-electronic sensor system.

A more detailed description of the different parts of the device and its utility are presented in the following sections :

Fig. 1, 2 and 3 illustrate the main components of the control device 1 which according to the invention comprise a control stick (finger-grip) 2 and a circular guide plate 3 which are incorporated in a computer chassis 4. The diameter of the motion range accessible to the control stick according to Fig. 2 is between 5 and 100 mm, and it is typically between 10 and 40 mm. Other embodiments of the invention may utilise other technical arrangements, where the motion range is e.g. rectangular, preferably with rounded corners . The guide plate may be totally or partially hidden.

Due to space considerations when used with portable computers, the control device is preferentially localised in a recess in front of the keyboard (Fig. 3) . The recess has slanting walls providing room to seize the stick 2 by two or more fingers . When incorporated in separate keyboards or control units, this recess is of less importance .

Due to ergonomic considerations, the position of the control device is of particular significance when used as part of a keyboard. The recess may be partially cut into the spacebar, as this will allow the user to reach the stick while the fingers are resting on the keyboard.

The guide plate is positioned and supported in a way that allows it to be moved freely and easily in all directions in the horizontal plane, but not vertically. A variety of plate supports may be used. For illustrative purposes, a support system is suggested in Fig. 4 as comprising the detector chamber walls 8 and the computer chassis 4, between which the guide plate is squeezed. It is important that the support system incorporates components and materials that does not wear during extensive use, and that access of stray light into the detector chamber is prevented.

When in use, the control stick is held between thumb and index finger, or a fingertip is placed on the top of the stick to obtain the intended cursor movement . The control stick may incorporate switch functions as indicated in Fig. 4. A micro-switch 5 is connected to the control stick's outer coat, which can be moved vertically relative to the guide plate. When the switch is in its normal position, any movement of the control stick in the horizontal plane will evoke a similar movement of the cursor or object on the screen. When the switch is depressed and attains an "activator" position (accompanied by felt "click"), a signal is sent to the object control unit in addition to the position information, equivalent to depressing the left mouse button. When the stick is lifted from its normal position (into the "null" area), the signal generation or signal transmission is disrupted and the control stick may be re-positioned in the X-Y plane without influencing the cursor position (equivalent to lifting and re-positioning the mouse) . In embodiments where a four-position switch is used, lifting the stick beyond the "null" area will activate a second switch function (a felt "click") and functions equivalent to those activated by the right mouse button are invoked.

With the switch function incorporated in the stick, it is unnecessary to change grip during activation of switch- associated commands. The switch function may alternatively be localised elsewhere on the control unit.

As a basis for motion-associated signal generation, the invention utilises light beams produced by diode lasers (6 and 7, Fig. 4) . The laser beams are directed towards a reflector plane 10 containing grids 11, 12 consisting of non-reflecting stripes. When the guide plate is moved in the horizontal plane, the grids will move relative to the striking beams and the reflected light will thus be pulse-formed. The reflected light pulses will be registered by a photosensor, which generates signals dependent upon the strength and frequency of the light pulses. These signals provide information about the control modules' movement and may be used for control of cursors or other virtual and physical objects.

In the embodiment of the invention illustrated in Fig. 4 the reflector plane 10 is localised on the underside of the guide plate 3. Two diode lasers are assembled into compact detector units 6, 7 together with photosensors and necessary optics. These units are attached to the bottom of the detector chamber.

Fig. 5 shows the reflector plane 10 with two separate grids, grid 11 which is used for detection of movement along the Y-axis (Y-grid) and grid 12 which is used for detection of X-movement (X-grid) . The non-reflecting (and reflecting) stripes of grid 11 are oriented at right angles to the Y-axis, while the stripes of grid 12 are oriented at right angles to the X-axis.

The non-reflecting stripes of the grids are produced by laser-engraving, magneto-polarisation (which implies that the detector system must incorporate polarisation filters) , or another form of engraving, surface modification or deposition of a light absorbing material on the surface of the reflector plane which eliminates or reduces the plane's reflectivity.

The grids may be circular, quadratic, rectangular or have another form and be of a size that as minimum covers the area that can be potentially hit by the laser beams when the control module is moved within its boundary.

Fig. 6 illustrates in more detail one of the detector units 6 that is identical or similar to the reading units used in CD players, CD-ROM, etc. It incorporates a diode laser 17, a prism 15, a focusing lens 15, a focusing coil 13 and a photodetector 16. The path of the laser beam from the diode laser 17 via the reflector plane 10 to the photodetector 16 is indicated. For the sake of simplicity the beam geometry is omitted.

This particular detector unit is not applicable when used in connection with a grid pattern as illustrated in Fig. 8. Here, both the non-reflecting 21 and the reflecting 22 stripes are of the same width. When the laser beams 23 traverse this grid, a pulse train will be generated by the photodetector with an appearance that is independent of the direction of movement; i.e. the pulse train gives no information about which direction along a certain axis the control module is moved.

When the non-reflecting and the reflecting stripes are of the same width as illustrated in Fig. 8, a detector arrangement as described in Fig. 7 must be employed. This detector incorporates two photosensors 19, 20 and a diverging lens 18.

When the laser beam 23 is traversing a grid (e.g. the X- grid) , a pulse train 24 will be generated from the two sensors A and B according to Fig. 8. The two pulse trains will be a quarter of a wavelength out of phase, and the phase shift will depend upon the direction of movement. (The pulse trains illustrated in this and subsequent figures are idealised. The device may incorporate a pulse generator or "timer" as reference. This and similar utilities are not particularly mentioned in this description, but is assumed to be well known to people skilled in the art) .

The embodiment illustrated in Fig. 9 employs a grid pattern that is "polarised" due to the non-reflecting (27, 28) and reflecting (25, 26) stripes being of unequal width. Fig. 9B shows a cross section of the reflector plane and illustrates how laser engraving may provide non-reflecting (27, 28) and reflecting stripes of dissimilar width.

When the laser beam traverses this grid pattern the photosensor will generate a pulse train that is characteristically different in +X and -X direction. It can be seen that in +X direction a pulse of medium length (M) will immediately precede a short pulse (S) , while the opposite is true in -X direction. This kind of grid pattern permits the use of just one photodetector per axis, and in addition allows for simpler optical arrangements than is needed with non-polarised grids.

A similar principle is utilised in Fig. 10 where the non- reflecting stripes are of the same width, but where the distance between them are unequal (forming reflecting stripes of different width, 29, 30, 31). Pulses that are generated will be long (L) , intermediate (M) and short (S) in duration, as indicated in Fig. 10B. This arrangement will also enable determination of direction with one photosensor.

A third set of polarised grids is shown in Fig. 11A where the reflectivity of the reflecting stripes are varied, e.g. in grades of 100% (32), 50% (33) and 30% (34). Pulse trains generated are illustrated in Fig. 11B, where a movement in +X direction generates an initial high (H) , followed by an intermediary (I) and finally a weak (W) signal .

Fig. 4 describes a preferred arrangement of control modules, photodetectors and reflector planes. Other arrangements are also permitted, e.g. as illustrated in Fig. 12. Here, the photodetectors 6, 7 are attached to the guide plate, while the reflector plane 10 is localised on the floor of the detector chamber. This embodiment requires more space.

Other embodiments may utilise more than one reflector plane and several photodetectors. The device may e.g. incorporate photo-electronics for detection of vertical and rotational movement of the control stick, in addition to translation movement of the guide plate beyond its normal mobility range. The device may thus be constructed and utilised for control of cursors and other objects both in two and three dimensions.

The device may also incorporate other signal generating systems; e.g. stress sensors that can be employed to provide continuous motion control (vectorial control) beyond the congruent X-Y motion control that can be achieved within the control modules' normal mobility boundaries. In Fig. 13, the incorporation of such stress sensors 35 connected to the control stick is suggested.

Claims

Patent claims

1. Device for positioning and control of computer cursors and other objects in two or three dimensions, where the device incorporates a control module comprising a finger- or hand-grip (control stick) that is attached to a guide plate; the guide plate can be moved in all directions in the X-Y plane by means of the stick; where movements of the control module is detected opto-electronically by means of reflector planes, light sources and photosensors that are connected to the control module or other parts of the device in such a way that they move relatively to each other when the control module is moved, whereby light beams hitting the surface of the reflector planes in areas containing non-reflecting grids will cause pulse-formed light reflections that are detected by photosensors; the device may further incorporate switches and pressure-sensitive sensors for detection of directional force applied to the control module in addition to a system for interpretation of the electronic signals that light pulses, switches and pressure sensors generate and transform these signals into information that can be used to control position, orientation, direction of movement, speed and other properties by said computer cursor or object; characterised in that at least one of the reflector planes is aligned parallel to the X-Y plane and that the non-reflecting grids on the surface of the reflector planes consist of non-overlapping groups of parallel, non-reflecting stripes with reflecting stripes in- between; where movements of the control module will cause light beams to traverse the different grids and thereby generate pulses of reflected light that provide information about the module' displacement along and around different axes.

2. Device for positioning and control of computer cursors and other objects in two dimensions, where the device incorporates a control module comprising a finger- or hand-grip (control stick; 2) that is attached to a guide plate (3); the guide plate can be moved in all directions in the X-Y plane by means of the stick; where movements of the control module is detected opto-electronically by means of a reflector plane, light sources and photosensors that are connected to the control modules or other parts of the device in such a way that they move relatively to each other when the control module is moved, whereby light beams hitting the reflector plane in areas containing non-reflecting grids will cause pulse- formed light reflections that are detected by photosensors; the device may further incorporate switches and pressure-sensitive sensors for detection of directional force applied to the control module in addition to a system for interpretation of the electronic signals that light pulses, switches and pressure sensors generate and transform these signals into information that can be used to control position, orientation, direction of movement, speed and other properties by said computer cursor or object; characterised in that the reflector plane is aligned parallel to the X-Y plane; that the reflector plane on its surface has two non-overlapping grids consisting of non-reflecting stripes with reflecting stripes in- between; where the stripes of the two grids are oriented at an angle of 90┬░ relative to each other; where one grid is used for detection of movement along the X-axis (the X-grid) and the other for detection of movement along the Y-axis (Y-grid) , and where a movement of the control module in the X-Y plane will cause light beams to traverse the X- and Y-grid, respectively, and thereby generate pulses of reflected light that provide information about the module' displacement along the X- and Y-axis.

3. A device according to claim 2, characterised in that the stripes of the X-grid are oriented at right angles to the X-axis and the stripes of the Y-grid are oriented at right angles to the Y-axis .

4. A device according to claims 2 and 3, characterised in that the reflector plane with the two grids are localised on the underside of the guide plate (3) .

5. A device according to claims 1-4, characterised in that the non-reflecting stripes of each grid are localised at an unequal distance from each other.

6. A device according to claims 1-5, characterised in that the non-reflecting stripes of each grid have different width.

7. A device according to claims 1-6, characterised in that the reflecting stripes between the non-reflecting stripes of each grid have a different degree of reflectivity.

8. A device according to claims 1-7, characterised in that the non-reflecting and partially reflecting stripes are created by a modification of the reflecting surface resulting in increased light dispersion, light absorption, light polarisation or other forms of changed reflectivity.

9. A device according to claim 8, characterised in that the non-reflecting or partially reflecting stripes are produced by laser-engraving, magneto-polarisation or deposition of a non-reflecting material, and that the stripes are between 1 micrometer and 200 micrometer in width and between 1 millimetre and 100 millimetre in length.

10. A device according to claims 1-9, characterised in that the light sources are laser sources.