WO1999012124A1

WO1999012124A1 - Cursor control device with position grids

Info

Publication number: WO1999012124A1
Application number: PCT/NO1998/000267
Authority: WO
Inventors: Steinar Pedersen
Original assignee: Steinar Pedersen
Priority date: 1997-09-02
Filing date: 1998-09-01
Publication date: 1999-03-11
Also published as: NO305150B1; NO974016L; NO974016D0

Abstract

Device for positioning and control of PC cursors and other objects, comprising a control module that can be moved within a defined area (mobility range), where the location of the module within its mobility range is determined by an opto-electronic sensor system. The sensor system incorporates light sources and a reflecting plane (10) that contains two or more grids consisting of non-reflecting stripes (11, 12), where sequences of non-reflecting and reflecting stripes in each grid form groups carrying information about their position relative to a co-ordinate axis, and where position information generated when light beams traverse the grids and reflected light pulses hit photosensors are used to define the position of the control module, which again is used as basis for control of cursors and other objects.

Description

Cursor Control Device with Position Grids

The described invention represents a control device intended for positioning and control of PC cursors and other objects, utilising a control module that can be moved within a limited area, where the location of the module within this area is determined by an optoelectronic sensor system. The sensor system incorporates light sources and a reflecting plane that contains two or more grids consisting of non-reflecting stripes, where sequences of non-reflecting and reflecting stripes in each grid form groups carrying information about their position relative to a co-ordinate axis, and where information generated when light beams are reflected from each grid and hit photosensors are used to define the position of the control module, which again is used to control cursors and other objects.

The most popular devices used for positioning and control of cursors and other graphical symbols and objects on the PC screen are mice, trackballs, trackpoints, joysticks and touch pads. Mice and trackballs are operated by hand and thumb, respectively, of which none are especially trained for very accurate movements. Other systems that utilise finger or hand control are described in 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 and EP A3 0,556,936.

This inventor has developed control devices previously described in PCT/NO94/00113, PCT/NO96/00077 and in PCT/NO98/00233, where the control module comprises a member that may be gripped by fingers or hand (control stick) , this member being attached to a plate (guide plate) . Devices based upon the stick-and-plate configuration satisfy many of the requirements of an ideal cursor control device. One important reason is that they may be handled according to writing or drawing motion and thereby utilise the very precise steering powers of hand, thumb and index finger in combination.

The device described in PCT/NO96/00077 utilises an optoelectronic sensor system. Here, lasers attached to the control module direct light beams towards reference planes containing sensor matrixes or address pixels. The spots where light beams hit the reference plane (s) determine the position and spatial conformation of the control module. This concept is used to control objects both in two and three dimensions.

Devices described in PCT/NO98/00233 employ a different sensor system. Instead of using concentrated light beams to determine the posi tion of the control module, diode lasers are here used to detect movement . Each time the control module is moved relative to a reflector plane containing grid patterns (consisting of parallel stripes), laser beams will traverse the stripe sets and create reflected light pulses. The pulse frequency and duration of the pulse trains will give information about speed, direction and extension of movement. The reflected pulses are detected by photosensors, and signals being generated are used to control screen cursors or other objects.

While control devices described in PCT/NO94/00113 and in PCT/NO98/00233 utilise the movement of a control module to generate signals indicative of direction and speed of movement, the device described in PCT/NO96/00077 utilises change of posi tion or spa tial conforma tion of the control module as control principle, making the device ideal e.g. for object control in three dimensions .

One of the sensor members utilised for determination of position according to PCT/NO96/00077 is a reference plane that is subdivided into pixels furnished with position addresses. Light sources attached to the control module direct light beams towards the reference planes, and light reflections generated when beams strike the address pixels will be detected by photosensors and the position determined by an analyser unit. Each pixel that is used for determination of position in the X-Y plane will carry both an X- and an Y-co-ordinate . However, the system used for reading the pixel addresses is rather complicated, which poses limitations on the utility of the system.

This inventor has surprisingly discovered that the stick-and-plate concept provides opportunities for eliminating the use of square pixels containing "two- dimensional" address information for determination of position in the X-Y plane. Instead, the two-dimensional pixels may be substituted by two sets of "one- dimensional pixels". In practical terms, two sets of parallel, non-reflecting stripes are imprinted on the surface of an otherwise reflecting plane (as X- and Y- grids) . The stripes of the grids are organised into groups, where each group constitutes a "one-dimensional pixel". Each pixel carries information about its position relative to one axis. The stripes of the two grids are oriented at right angles to each other. (Additional, one-dimensional grids may be used to determine position along the Z-axis and inclination and rotation around axes in connection with 3-D applications) . This particular arrangement of one-dimensional position grids permits usage of very narrow stripes, enabling very high resolution and sensitivity. This provides opportunities for miniaturising and employment of a very simple photosensor arrangement.

The grids are produced by laser engraving, magneto- polarisation or deposition of a light absorbing material in the form of parallel stripes on the surface of a reflecting plate (reflector plane) .

In order to determine the position, laser beams emitted by diode lasers are generally employed. However, other forms of directed, concentrated light beams or other electromagnetic radiation may be used. For simplicity reasons, the terms laser beams and laser sources will be throughout the document.

Each time a control module is moved relative to the reference plane, laser beams will traverse grids and cause formation of reflected light pulses. The pulses' duration and the time intervals between individual light pulses will provide position information.

Unlike the control device described in PCT/NO98/00233, which utilises the movement of a control module to generate pulses controlling the movement of a cursor or object, this invention utilises the posi tion of the control module for control purposes. This is advantageous under certain circumstances. One advantage is that every point within the control module's mobility range may represent a defined location on the computer screen. A certain module position will therefore always give the same cursor position, abolishing the need for utilities that extend cursor movement when the control module reaches the outer limit of its mobility range. Another advantage is that it provides an opportunity to define addresses or zones within the module's mobility range that are given certain functions. One example is described in PCT/NO98/00242, where address pixels are used to define a fringe zone where the control mode change from congruent to vector-based cursor control.

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 constitute essential parts of the control module. 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 suitable 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 mobility to a defined area of the plane, equivalent to a circle with a diameter of 5-200 mm (the mobility range) . The area may have an arbitrary form, but it is advantageously rectangular or square with rounded corners, or circular. The control module is defined to be in its "normal" position when the stick and plate is localised in the centre of the mobility range.

The stick may be flexibly mounted on the guide plate, which permits a simultaneous movement of the two module members relative to stationary parts of the device, and at the same time allows the stick to be displaced relative to the guide plate. Under such circumstances the device may be equipped with flexible parts (flexible collars, springs, pneumatic devices, etc.) which may automatically bring the stick back to a normal, preferred position relative to the plate unless it is exposed to a sustained, 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 module to initiate cursor or object movements unless the position changes have passed a certain threshold value.

The signal generating system (the sensor system) incorporates two or more light sources, e.g. diode lasers that are directed towards the reflector plane. Light beams hit the grid areas and are reflected as discrete light pulses when the control module is moved. Photosensors detect these reflections and signals generated by the sensors are used to define the control module's position, which is again used to control screen cursors or other objects.

The stick-and-plate configuration and the optoelectronic sensor system described herein may very well be combined with stress or pressure sensors for isometric motion 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, the guide plate or other parts of the device, and provide an extra set of vector-based control signals.

It is advantageous to localise said stress sensors in a way that allow them to be activated when an attempt is made to move the control module beyond its normal mobility range. In this way, the stress-generated signals may be used to extend a movement that would otherwise be limited by the control module' 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 members of the control module.

Fig. 2 shows a perspective drawing of the control module when incorporated in a chassis.

Fig. 3 shows the control module 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 plane containing two sets of grids with "one-dimensional pixels".

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

Fig. 7 shows a section of the X-grid with two "one- dimensional pixels".

Fig. 8 shows signals being generated when a laser beam traverses the X-grid.

Fig. 9 shows the use of stripes with varying width.

Fig. 10 shows signals generated when a laser beam traverses a set of stripes with varying width. Fig. 11 shows the use of stripes with varying reflectivity.

Fig. 12 shows signals being generated when a laser beam traverses a set of stripes with varying reflectivity.

A more detailed description of different parts of the device and their use are presented in the following:

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 guide plate 3 which are incorporated in a chassis 4. The diameter of the mobility range according to Fig. 2 is between 5 and 100 mm, and is typically between 10 and 40 mm. Other embodiments utilise a rectangular or square mobility range, preferably with rounded corners.

When used with portable computers, the control device is preferably localised in a recess in front of the keyboard (Fig. 3) . The recess has slanting walls to provide room for seizing 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 then 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. It is important that the support system incorporates components and materials that does not wear during extensive use, and that stray light is prevented from reaching the detector chamber.

When in use, the control stick is held between the thumb and index finger, or a fingertip is placed on 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 pressing 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 equivalent to pressing the right mouse button.

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

As basis for a position-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 beams and reflected light will thus be pulse-formed.

The reflected light pulses will be registered by a photosensor, which generates signals according to the strength and frequency of the light pulses. These signals provide information about the control module' position and may be used to control cursors and other objects .

In a preferred embodiment of the invention as 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 determination of position along the Y-axis (Y-grid) and grid 12 which is used for determination of X-position (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, reduces or in other ways changes the plane's reflectivity.

The grids may be circular, square, rectangular or have an arbitrary shape. However, the size and shape must as a minimum cover the area that can be potentially hit by the laser beams when the control module is moved within its mobility range.

Fig. 6 illustrates in more detail one of the employed detector units 6. It is identical or similar to the reading units used in CD players, CD-ROM, etc., incorporating 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 simplicity reasons, the beam geometry is omitted.

Fig. 7 shows a section of the X-grid, where a small part of the "one-dimensional pixels" is represented. Each pixel has addresses encoded as sequences of parallel non-reflecting and reflecting stripes, 18 and 19. In this embodiment, the widths of the stripes are equal. The two pixels are separated by a set of stripes (s; 20) with a width that is different from the position stripes. The stripe set s has a double function; to separate each address group and to act as a pulse frequency reference (in addition to, or instead of a constant pulse generator) . The Y-grid has an identical set of "one-dimensional pixels", but the stripes are oriented at right angles to the Y-axis.

When the control module is moved in the X-Y plane, laser beams will traverse the X- and Y-grid. The reflected light pulses will be registered by photosensors 16 (Fig. 6) , which transmit signals according to frequency, strength and duration of the pulses. A typical signal is represented in Fig. 8, showing signal strength as a function of time.

The signals from the photosensors are processed in an analogue/digital converter, and together with signals from a constant pulse generator (or separation pulses; s) used to determine position addresses. The result of this signal processing is indicated in Fig. 8, showing a signal sequence 21 together with a derived, binary address. Fig. 8 also illustrates the signal 22 that is generated when the laser beam crosses the border (s) between two pixels.

Pixel addresses are preferentially expressed on binary form, but they may also be encoded in other number systems. This is indicated in the following figures, where e.g. the grids in Fig. 9 employ reflecting stripes of three different widths (25, 26, 27). The light pulses have different duration, as have the accompanying signals (L, M, S; Fig. 10) . A similar result may be obtained by varying the stripes' reflectivity (28, 29, 30; Fig. 11), creating signals of varying strength (H, I, W; Fig. 12) . By using suitable discriminators in the analyser circuit, a certain signal strength and/or duration may be allotted a certain value and thus used as part of address information. Devices that are encompassed by this invention may be equipped with more photodetectors and reference planes than are described above, and such embodiments will be obvious to a person skilled in the art. The device may e.g. incorporate detector systems for determination of vertical position, rotation and inclination of the control stick, in addition to sensors detecting lateral displacement of the guide plate beyond its normal mobility range. For this reason, the device here described may be used for control of cursors and other objects both in two and three dimensions.

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 is used to control position, orientation, direction of movement, speed or other properties by said cursor or object; chara cterised in that the non-reflecting pattern on the reflector plane comprises at least two separate grids, where each grid consist of parallel, non-reflecting stripes with reflecting areas in-between; where one of the grids is used for determination of position relative to the X-axis (X-grid) and another for determination of position relative to the Y-axis (Y-grid) and where a movement of the control module in the X-Y plane makes the light beams cross the X- and Y- grids, generating pulses of reflected light that will define the position of the light beams and the module relative to the X- and Y-axis .

2. A device according to claim 1, characterised in that the X- and the Y-grid are located in a reflector plane that is oriented parallel to the X-Y plane and where 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.

3. A device according to claims 1-2, characterised in that the non-reflecting and reflecting stripes are organised into groups, where the combination of stripes in each group carries information about the groups' position relative to a certain co-ordinate axis.

4. A device according to claim 3, characterised in that the non-reflecting or reflecting stripes of each group have unequal widths.

5. A device according to claims 3 and 4, chara cterised in that the reflecting stripes have a varying degree of reflectivity.

6. A device according to claims 1-5, characterised in that the non-reflecting and the reflecting or partially reflecting stripes have a width between 0.1 micrometer and 500 micrometer.

7. A device according to claims 1-6, characterised in that the reflector plane with the two grids is localised on the underside of the guide plate.

8. A device according to claims 1-7, characterised in that the non-reflecting and the partially reflecting stripes are formed by modification of a reflecting surface that produces light dispersion, light diffraction, light absorption or another form of reduced or changed reflectivity.

9. A device according to claim 8, characterised in that the non-reflecting or partially reflecting stripes are formed by laser engraving, magneto-polarisation or deposition of a non-reflecting or partially reflecting material .

10. A device according to claims 1-9, characterised in that the light source is a laser source.