Abstract
A reading device is for reading a positional relationship between a first component and a second component. The first component has an optical sensor and the second component has a collimator configured for directing a light beam at the optical sensor. A method is for reading a positional relationship between two components, the method including passing light through a collimator in a first component towards an optical sensor in a second component, reading the position of the light beam from the collimator on the optical sensor, and calculating the positional relationship between the first and second components from the position of the light beam on the optical sensor.
Claims
1. A reading device for reading a positional relationship between a first component and a second component, wherein the first component comprises an optical sensor and wherein the second component comprises a collimator configured for directing a light beam at the optical sensor by the collimator comprising a collimator housing with two openings opposite each other, each in a respective end part of the collimator housing.
2. The reading device according to claim 1, wherein the size of the openings and the distance between the openings in the collimator are so adapted that the light beam behind the collimator has a cross section of an extent smaller than 50 μm.
3. The reading device according to claim 2, wherein the size of the openings and the distance between the openings of the collimator are arranged in such a way that the light beam after the collimator has a cross section of an extent smaller than 10 μm.
4. The reading device according to claim 1, wherein the optical sensor is an image sensor.
5. The reading device according to claim 1, wherein the optical sensor has a pixel size with dimensions smaller than 50 μm.
6. The reading device according to claim 1, wherein the optical sensor has a pixel size with dimensions smaller than 10 μm.
7. The reading device according to claim 1, wherein the collimator is further configured for directing a second light beam at the optical sensor.
8. The reading device according to claim 7, wherein the collimator is further configured in such a way that the light beams hit the optical sensor at different angles.
9. The reading device according to claim 1, wherein the collimator, on its inside, has a surface which absorbs light.
10. A method for reading a positional relationship between two components, wherein the method comprises the steps of: passing light through a collimator in a second component to an optical sensor in a first component, the collimator comprising a collimator housing with two openings opposite each other, each in a respective end part of the collimator housing; reading the position of the light beam from the collimator on the optical sensor; and calculating the positional relationship between the first and second components from the position of the light beam on the optical sensor.
11. The method according to claim 10, wherein the positional relationship between the two components is read by using the reading device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] In what follows, examples of preferred embodiments are described, which are visualized in the accompanying drawings, in which:
[0035] FIG. 1 shows a cross section of a joystick in one embodiment of the device;
[0036] FIG. 2 shows, in perspective, a joystick in another embodiment of the device;
[0037] FIG. 3 shows a view from the side of a joystick in which further details of the device are shown;
[0038] FIG. 4 shows a cross section of a joystick in still another embodiment of the device;
[0039] FIG. 5 shows a cross section of an embodiment of the device in the form of a computer mouse;
[0040] FIG. 6 shows a cross section of a collimator built into the movable part of the device;
[0041] FIG. 7 shows a cross section of a collimator built into the movable part of the device in another embodiment;
[0042] FIG. 8 shows a cross section of a collimator built into the movable part of the device in still another embodiment;
[0043] FIG. 9 shows a cross section of a collimator built into the movable part of the device in still another embodiment;
[0044] FIG. 10 shows a section of an optical array in which a position of the movable handle element is read in one embodiment of the device;
[0045] FIG. 11 shows a section of an optical array in which another position of the movable handle element is read in one embodiment of the device;
[0046] FIG. 12 sows a cross section of an embodiment of the device in the form of an inclinometer.
DETAILED DESCRIPTION OF THE DRAWINGS
[0047] In the drawings, the reference numeral 100 indicates a reading device. FIG. 1 shows the reading device 100 which comprises a handle element 1a in which a light source 2 that can receive energy via a control circuit 3 and a battery 4 are installed. The handle element 1a may have an access hatch 1b for access to the components that are in the handle element 1a. As a continuation of the lower part of the handle element 1a, there is a tubular extension which forms a collimator housing 5. The shaft element 6 surrounds the collimator housing 5 and functions as a support for the collimator housing which, together with the handle element 1, is rotatable relative to the shaft element 6. A fastener 1c may be used to hold the handle element 1a and collimator housing 5 together with the shaft element 6. The shaft element 6 is attached to a ball half 7a and a ball half 7b which are made from an electrically conductive material with an insulating material between the ball halves (not shown). The ball half 7a and ball half 7b are held together by an upper joint half 9 and a lower joint half 10 which together with the ball half 7a and the ball half 7b form a ball joint. The lower joint half 10 is attached to a bottom structure 11a by means of spacers 12. In the bottom structure 11a, there is a mounting device 13 for an optical array 14 which is located below the pivotal point 7d of the ball joint. In the lower joint half 10, electrical brushes 15 which are in contact with the ball half 7a and the ball half 7b are arranged. The electrical brushes 15 are supplied with electric power via electrical connection points 16 and carry electric power via the electrical brushes 15, further through the ball half 7a and the ball half 7b, then on through an associated electrical connection in the shaft element 6 and on to an electrical inductive circuit consisting of a primary coil 29 arranged in the shaft element 6. A secondary coil 30a is arranged in the handle element 1a, and a connection between the secondary coil and the control circuit 3 is arranged with electrical connection 30b via a circuit board 1e which also functions as a mounting plate for the control circuit 3 and battery 4. The primary coil 29 and the secondary coil are arranged in line with each other. The light from the light source 2 is gathered by means of a collimator into one or more approximately unidirectional microscopic light beams. The collimator may consist of an upper collimator element 17 and a lower collimator element 18 which are each installed in a respective end of the collimator housing 5. The end of the lower collimator element 18 where the collimated light exits is preferably arranged in the pivotal point 7d of the ball joint shown in FIG. 3. The material of the ball half 7a and the ball half 7b has been removed under the pivotal point 7d of the ball to make room for an optical array 14 and its mounting device 13. The collimated light illuminating the optical array 14 gives position data related to the position of the handle element 1a, and data may be extracted via a data cable 32 and processed in a control unit or computer, for example for controlling a machine. To prevent impurities from getting into the reading unit 100, a rubber sleeve 8 may be installed and attached between the joint half 9 and the outer shaft element 6. To prevent undesired light from falling on the optical array 14, a casing 11b may be used. As a substitute for the bottom structure 11a and the casing 11b, a complete structure forming the sides and bottom may be used.
[0048] FIG. 2 shows a variant of a reading device 100 which is movable by means of a cardan suspension 19. Directional indications on the optical array 14 are in the horizontal plane by the x-axis, representing the directions forward/rearward, and the y-axis, representing the directions right/left. A direction in the vertical plane is indicated as the z-axis. A rotation around the z-axis is indicated as Ro. In such a variant, feeding electrical power to the light source can be done via an electrical connection 16, further via electrical conductors through the axles 20 of the cardan suspension 19 by the use of sliprings and further up to the light source (not shown) via the shaft element 6. In this variant, the handle element 1a is provided with extra control functions with switches 1dI, 1dII and 1dIII.
[0049] FIG. 3 shows a reading device 100 in which the handle element 1a is not shown. The centring of the handle element 1a in a neutral position consists in springs 23a that are attached between the outer shaft element 6 and fastening devices for springs 23b. Fastening devices for springs 23b typically consist of four units evenly spaced and attached to the upper joint half 9. The ball half 7a and the ball half 7b are electrically isolated from each other by an insulator 7c. The ball half 7a and the ball half 7b constitute the ball of the ball joint, and the centre point of the ball may be termed the pivotal point 7d of the ball.
[0050] FIG. 4 shows a variant of a reading device 100 in which the handle element 1a is not shown. Electric power for the light source (not shown) is made by way of electrically induced voltage from the static part of the reading device 100 to the movable part of the reading device 100. An alternating current is supplied to a primary coil 29 via a supply cable 31. The alternating current induced in the secondary coil 30 is passed on through an electrical connection arranged from the secondary coil 30 via the shaft element to the control circuit 3 and the battery 4 (not shown) of the light source 2. After having been installed in the ball forming the ball joint, the secondary coil 30 may be anchored, for example by means of a potting compound 7e. The variant of the reading device 100 as shown in FIG. 4 is of a type which uses a ball joint as the pivotal point 7d of the handle element 1a (not shown) and in which rotation around the z-axis is a function used. To prevent the ball of the ball joint from rotating when the handle element 1a (not shown) and the collimator housing 5 with the lower collimator element 18 are being rotated, guiding grooves 22 may be made on both sides of the ball joint. The longitudinal direction of the guiding grooves 22 is oriented perpendicularly to the horizontal plane when the handle element 1a is in the centre position, and is preferably aligned on both sides of the ball on the x-axis or the y-axis and centred around the pivotal point 7d on the ball joint. The width of the guiding groove 22 may typically be 10% of its length. Between the upper joint half 9 and the lower joint half 10, cylindrical guide pins 23 are arranged, extending into the guiding groove 22. The ball joint will thus allow movement on the x-axis and y-axis without any possibility of the ball of the ball joint rotating around the z-axis. The length of the guiding groove 22 must be so long that it allows the desired movement of the movable part of the reading device 100 which will be restricted by the length of the guiding groove 22. As the technique used is not affected to any great extent by magnetic fields, centring of the handle element 1a may be carried out by means of a magnet 24 arranged in the lower part of the ball forming the ball joint. The magnet 24 may be an annular magnet of a permanent magnet type. In the bottom structure 11, a magnet 25 is arranged, which may be an annular magnet. The magnet 24 of the movable part of the reading device 100 and the magnet 25 of the static part of the reading device 100 are arranged with like magnet poles facing each other so that they repel each other and will thus keep the handle element 1a in a neutral position. The magnet 24 of the movable part of the reading device 100 and the magnet 25 of the static part of the reading device 100 may also be placed in another place that will give a centring of the handle element 1a. The magnet 25 of the static part may also be replaced by 3 or more solenoids on the bottom structure 11, evenly spaced around the centre line A which is formed by the centre of the collimator housing 5 when the handle element 1a is in its centre position. Alternatively, there is a set of solenoids (not shown) in addition to the magnet 25. This will make it possible to provide for a feedback to the handle element 1a on forces to which the thing(s) that the reading device 100 is to control is/are subjected, also called force feedback.
[0051] FIG. 5 shows a reading device 100 in a trackball embodiment for use as a computer mouse. The control circuit 3 and the battery 4 for supplying the light source 2 are built into the trackball 28, together with the collimator which may consist of an upper collimator element 17 and a lower collimator element 18. The collimator housing 5 may also consist of an element that has the microscopic aperture. An alternative to a collimator housing 5 mounted in the trackball 28 is that the material in the trackball 28 forms the collimator with the microscopic aperture. The trackball 28, the upper joint half 9 and the lower joint half 10 may be provided with guiding grooves 22 and cylindrical guide pins 23 (not shown), as shown in FIG. 4, to avoid rotation of the trackball around the z-axis. The reading device 100 may also be used without guiding grooves 22 and cylindrical guide pins 23 as a collimator having just one aperture 21a is being used and a rotation around the z-axis will not affect the position reading of the light beam on the optical array 14. The trackball 28 may have a stop edge 7f which restricts the movement of the trackball 28 by the stop edge 7f stopping against the lower joint half 10 and ensuring that the light spot from the collimator will not go beyond the chosen reading area of the optical array 14. Power supply to the light source 2 may be done via an electrical primary coil 29 which may be placed between the upper joint half 9 and the lower joint half 10, receiving supply voltage via a supply cable 31. The primary coil 29 is inductively connected to a secondary coil 30 which is electrically connected to the control circuit 3 of the light source 2 which may charge a battery 4 in order to give a controlled voltage to the light source and thus a more even light intensity. Power supply may also be done via electrical brushes as described for the reading device 100 of FIG. 1. Power supply may also be carried out by the battery 4 being charged by means of a charging contact or inductive charging of a battery 4 when the reading device 100 is not in use. Data from the optical array 14 are extracted from the reading device 100 via a data cable 32, or data are transmitted to the computer via prior-art wireless communication techniques.
[0052] FIG. 6 shows a selection of elements of a reading device 100 in which light from a light source 2 is collimated and directed at an optical array 14 by means of a version of the collimator that may indicate positions on the x- and y-axis. The collimator may consist of a collimator housing 5, an upper collimator element 17 and a lower collimator element 18 being mounted in the collimator housing 5. Transparent collimator-element protection 17b is fitted to the outside of the upper collimator element 17 and the lower collimator element 18. The upper collimator element 17 and the lower collimator element 18 have only one aperture 21a at the centre of the collimator housing 5. The collimator may also consist of more than two collimator elements with apertures 21a arranged in line in order to form a collimated light beam 21b. The collimator housing 5, the upper collimator element 17 and the lower collimator element 18 will preferably be made of a black matt material which absorbs light entering through the upper collimator element 17 at an angle to the line indicating a collimated light beam 21b. This will prevent light reflections 26 that might arise in the collimator housing 5 and thus minimize the possibility for light to pass the lower collimator element 18 at an angle to the desired collimated light beam 21b. The diameter of the aperture 21a is typically in the region of 1.5 times larger than a pixel of the optical array 14. This will ensure that the light spot that illuminates the optical array 14 will always illuminate a pixel 14a, thus avoiding a drop-out of the position signal.
[0053] FIG. 7 shows a selection of elements of a reading device 100 in which light from a light source 2 is collimated and directed at an optical array 14 by means of a version of a collimator that can indicate positions on the x- and y-axis and also rotation around the z-axis. The upper collimator element 17 and the lower collimator element 18 are arranged with two apertures 21aI and 21aII, giving two collimated light beams 21bI and 21bII. To prevent light entering through the aperture 21aI of the upper collimator element 17 at an angle relative to the direction of the apertures from passing the aperture 21aII of the lower collimator element 18 and making the light beam that hits the optical array 14 into a light beam that does not correspond to the diameter and shape of the apertures 21aI and 21aII, the collimator may be provided with a middle collimator element 27 which will stop light entering the upper collimator element 17 at an angle to the collimated light beams from continuing down towards the lower collimator element 18. A middle collimator element 27 may be installed and held in place by a supporting sleeve 27b. The apertures in the upper collimator element 17, the lower collimator element 18 and the middle collimator element 17 are of identical designs, positioning and have the same orientation in the horizontal plane. One light beam will preferably be aligned with the pivotal point on the reading device 100 and represent the position of the reading device, and the other light beam will be used to determine the degree of rotation around the z-axis.
[0054] FIG. 8 shows a selection of elements of a reading device 100 in which light from a light source 2 is collimated and directed at an optical array 14, and which can indicate the position of the handle element 1a (not shown) on the x- and y-axis, and the position of the handle element 1a (not shown) on the z-axis and also rotation around the z-axis. The collimator has an upper collimator element 17 and a lower collimator element 18 with three apertures, the three apertures being oriented on the same line in the horizontal plane. A middle collimator element 27 having an aperture at its centre may be used to reduce the spreading of the light beams in the same way as described for the collimator of FIG. 7. The light beam 21bI may be used to indicate the position of the handle element 1a on the x- and y-axis. The light beam 21bII and the light beam 21bIII form an angle relative to the light beam 21bI. When the handle element 1a with the collimator is moved in the direction z, with an increasing distance h between the collimator and the optical array 14, the distance l between the light beam 21bII and the light beam 21bIII will increase. When the handle element 1a with the collimator is moved in the direction z, with decreasing distance h between the collimator and the optical array 14, the distance l between the light beam 21bII and the light beam 21111 will decrease. A change in the position of the handle element 1a in the z-direction may thus be determined by using the difference between the highest row figure and the lowest row figure on the optical array in the program processing the signals of the reading device 100 and thus give a reading device 100 an extra dimension for position determination. To calculate the rotational direction and the degree of rotation, 21bII and 21bIII may be used, for example. This principle will be described in further detail with FIG. 10 and FIG. 11.
[0055] FIG. 9 shows a selection of elements of a reading device 100 in which light from a light source 2 is collimated and directed at an optical array 14 by means of a collimator that indicates positions only in the x- and y-direction, the collimator housing 5 consisting of just one element. The length from the aperture 21a, where the light enters, to the aperture where collimated light 21b exits the collimator housing 5 will be of importance to the spreading of light, and an aperture of a large length gives less light-spreading of the light exiting a collimator element than an aperture of a shorter length.
[0056] In FIG. 10 and FIG. 11 it is described how the position of a handle element 1a can be determined by means of the technique covered by the invention. In FIGS. 10 and 11, a section of an optical array 14 which is indexed by each pixel 14a having its address indicated by a first digit as the row number and a second digit as the column number which we call the index number. For information, index numbers of pixels in the optical array 14 are indicated in all four corners of the section. In the example given, a handle element 1a that has forward/aft and right/left movement and a possibility of rotation around the z-axis has been chosen. The optical array 14 has 4096×4096 pixels 14a. The rows R represent the position of the handle element 1a in the y-direction, and the column K represents the position of the handle element 1a in the x-direction. In this example, the index numbering of the individual pixels 14a is given as a first figure=row and a second figure=column. A centre position of the optical array then has an index number 2048,2048. The position indication for the handle element 1a may be chosen to be the signal generated by the collimated light spot that is on the highest column figure. A movement of the handle element 1a forwards will move the light spots towards an increasing column figure, and a movement of the handle element 1a rearwards will move the light spots towards a decreasing column figure. A movement of the handle element 1a towards the left will move the light spots towards a decreasing row figure and a movement of the handle element 1a towards the right will move the light spots towards an increasing row figure. The handle element 1a is preferably mechanically restricted in such a way that the light spots will stay inside the optical array 14.
[0057] FIG. 10 shows a section of an optical array 14 in which the handle element 1a is in the position at the extreme rear and extreme left. Index numbers of pixels in the optical array 14 are indicated in all four corners of the section of the optical array 14. The handle element 1a has no rotation around the z-axis which is indicated on the handle element 1a by an arrow that corresponds to the direction straight forward. The handle element 1a is provided with a collimator which gives two light spots on the optical array 14. The light spot Po indicates the position of the handle element 1a, and the light spot Ro will, together with the position of Po, be determinant for calculating the direction of rotation and magnitude of a rotation signal i. The light spots are positioned along the same row figure when there is no rotation around the z-axis, and the light spot of the handle element 1a for position indication Po=9,10 and the light spot for the rotation indication Ro=9,4. In this case the row figure is 9 for Po and Ro.
[0058] In FIG. 11, the handle element 1a is in the position extreme forward and extreme left, and the mechanical restriction of the handle element 1a gives the light spot for the position indication Po an index number=4087,4092 in the example. A maximum angle of rotation may be mechanically restricted to 45 degrees, and rotation around the z-axis is, in this case, 45 degrees towards the left. The light spot for the rotation indication Ro then has the index number 4092,4087. A row figure for the light spot Ro which is higher than the row figure for Po will indicate rotation towards the left, and a row figure for the light spot Ro that is lower than the row figure for Po will indicate rotation towards the right. A maximum rotation towards the left gives a row figure for Ro that has a value higher by 5 than the row figure of Po. When the handle element 1a is moved back towards zero rotation, a higher row figure for Ro than for Po will decrease until the row figure values are identical. A maximum rotation towards the right will give a row figure for Ro which is lower by 5 than the row figure for Po. In that way, the magnitude of the rotation signal and the direction of rotation may be calculated. By increasing the distance between the apertures 21a in the collimator, one will get an increased resolution of a rotation signal if this is desirable.
[0059] A person skilled in the art may use data from the optical array 14 generated by the collimated light from the collimator of the reading device 100 and provide for the output signal to user equipment to be of the desired standard. This may be done by necessary control electronics being located in the reading device 100 or being located separately from the reading device. Data from the optical array 14 may also be coupled directly to a computer and by means of the necessary software generate control signals to units that are to be controlled by the reading device 100.
[0060] FIG. 12 shows a reading device in the form of an inclinometer in which a pendulum 33 is suspended from an upper structure 34 by means of a universal joint which has an upper joint segment 39a and a lower joint segment 39b with low friction. Another type of device for suspending the pendulum may also be used. The upper structure 34 may consist of a detachable lid for access to the pendulum 33 with its contents. The upper structure 34 with the pendulum 33 is held by an outer structure 35 which may be a tubular cylinder which is installed on a bottom structure 11. In the pendulum 33, a light source 2 and a collimator consisting of an upper collimator element 17 and a lower collimator element 18 are arranged, the pendulum 33 constituting the collimator housing. The collimator may also be an independent collimator housing which is fitted into the pendulum 33. The light source 2 may be supplied with electric power by induced voltage transmission between the static part and the movable part of the reading device 100. This may be done by the control unit 40 being supplied with electric power via a supply cable 41 which may then supply the light source 2 with electric power via a cable 42 extending to the light source 2 via a primary coil 29 in the upper structure 34 and a secondary coil 30 installed in the top of the lower joint segment 39b and via a cable 44 to a light-control circuit 45. The collimated light 21b is directed at an optical array 14 which is mounted on the bottom structure 11. The bottom structure 11 may be fixed to the supporting surface that is to be monitored for angular changes by means of preferably three attachment points 36. The bottom structure 11 may have adjustments 37 so that, after installation on the supporting surface 38, the inclinometer may be adjusted in such a way that the collimated light 21b hits the centre of the optical array 14. If, over time, there is an angular change in the supporting surface 38, this will result in the pendulum and the collimated light 21b moving on the optical array 14 and new position data being transmitted to the control unit 40 via the signal cable 43. The amount of angular change and the direction of the angular change may be calculated in the control unit 40. The control unit 40 may also be located on the inside of the outer structure 35 or as part of a common circuit board on which the optical array 14 is located as well. The bottom structure 11 and the outer structure 35 are made lightproof so that only the collimated light 21b illuminates the optical array 14. The inclinometer may be installed in varying forms of outer structures 35. The inclinometer may have control electronics in the control unit 40 which make measurements continuously or at desired intervals, wherein data may be read directly on the inclinometer or stored on a built-in storing medium. Data may also be transmitted to a computer which may be integrated in the reading unit 100 or which is an external unit in which data are processed, stored or transmitted over an Internet connection to a receiver according to the prior art. A person skilled in the art may use data from the optical array 14 that are generated by the collimated light from the collimator of the reading device 100 and provide for a desired reading for a user of the equipment.
[0061] It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive.
[0062] The use of the verb “to comprise” and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article “a” or “an” before an element does not exclude the presence of several such elements.
