Micro-optical orientation sensor and related methods

Abstract

The sensor (1) for determining an orientation of the sensor in a gravity field comprises a ball (2) and a rolling surface (R) describing a generally concave shape on which the ball can roll inside the sensor. A further surface (F) is arranged opposite said rolling surface, and a light emitter (E), a light detector (D) and another light emitter or detector is provided. A region (R) within which the ball (2) can move is limited by at least the rolling surface (R) and the further surface (F). And the light emitters (E) and detectors (D) are arranged outside the region (R) for emitting light through the rolling surface (R) into said region and detecting light exiting the region (3) through the rolling surface (R) or for emitting light through the further surface (F) into said region (R) and detecting light exiting said region (R) through the further surface (F). Corresponding measuring methods and manufacturing methods are described, too.

Claims

1. A sensor for determining an orientation of the sensor in a gravity field, the sensor comprising: a ball; a rolling surface describing a generally concave shape on which said ball can roll inside the sensor; a further surface arranged opposite said rolling surface; a first active optical component which is a light emitter; a second active optical component which is a light detector for detecting light emitted by said light emitter; a third active optical component which is a light emitter or is a light detector; wherein a region within which said ball can move inside the sensor is limited by at least said rolling surface and said further surface, and wherein said active optical components are on a first substrate and are arranged outside said region for emitting light through said rolling surface into said region and detecting light exiting said region through said rolling surface, respectively, a sensor axis, the first substrate being arranged to extend in a direction perpendicular to the sensor axis, and a shortest distance between the rolling surface and the first substrate differs for different points along the rolling surface, wherein the shortest distance between the rolling surface and the first substrate for the different points coincides with or is parallel to the sensor axis.

2. The sensor according to claim 1, the sensor having a default orientation in which said sensor axis is oriented antiparallel to a direction of gravity.

3. The sensor according to claim 2, wherein said rolling surface is shaped such that said ball can be in a default position on the rolling surface when the sensor is in its default orientation, wherein, with the sensor being in its default orientation and said ball being in said default position, potential energy of said ball increases with a movement of said ball on said rolling surface into any direction.

4. The sensor according to claim 2, wherein for the shape of the rolling surface applies that the further away from the sensor axis, the steeper is the rolling surface or at least an averaged surface of the rolling surface.

5. The sensor according to claim 1, wherein said rolling surface generally describes a portion of an ellipsoid.

6. The sensor according to claim 1, wherein the sensor comprises a reflective or metallic surface or interface which is present at said further surface or at a surface or interface present behind said further interface as viewed from the rolling surface.

7. The sensor according to claim 1, comprising a concave body comprised in or attached to a generally flat substrate, wherein the shape of said rolling surface is determined by said concave body.

8. The sensor according to claim 1, comprising second and third substrates, wherein said active optical elements, said ball and said region are located between said first and third substrates, and said second substrate is arranged between said first and third substrates and being, at least in part, transparent.

9. The sensor according to claim 8, said second substrate comprising at least one non-transparent area and at least one transparent area.

10. The sensor according to claim 8, wherein at least one lens or lens element is comprised in or attached to said second substrate.

11. The sensor according to claim 8, comprising a first spacer, said first spacer being arranged between said first and third substrates, wherein said first spacer is continuous with at least one substrate of the sensor, and wherein a distance parallel to the sensor axis between said rolling surface and said further surface is determined by said first spacer.

12. The sensor according to claim 11, further comprising a second spacer being arranged between said first and second substrates; wherein said second spacer is continuous with said second spacer, and wherein a distance between said first and second substrates is determined by said first spacer.

13. The sensor according to claim 11, wherein said first spacer provides a stop surface, said stop surface contributing to limiting said region.

14. The sensor according to claim 1, comprising a fourth active optical component which is a light emitter or is a light detector.

15. The sensor according to claim 1, wherein said rolling surface has furrows or corrugations.

16. A device comprising at least one sensor according to claim 1, wherein the device is at least one of a portable or portable mobile device; a smart phone; a tablet computer; a digital reader; a photographic device; a digital camera; a game controller; a device comprising a display, wherein the device is operationally connected to said sensor for controlling said display in dependence of said orientation of said sensor; a tilt determining device for determining a tilt of an object relatively to which said sensor is fixedly positioned; an orientation determining device for determining an orientation of an object relatively to which said sensor is fixedly positioned; a controller for controlling an actuator or at least a part of a machine or at least a part of an engine or at least a part of a drive; a machine comprising a controller for controlling at least a part of the machine in dependence of signals outputted by said sensor; an engine comprising a controller for controlling at least a part of the engine in dependence of signals outputted by said sensor; a drive comprising a controller for controlling at least a part of the drive in dependence of signals outputted by said sensor.

17. The device according to claim 16, wherein the device comprises a printed circuit board, wherein said sensor is mounted on said printed circuit board.

18. A sensor for determining an orientation of the sensor in a gravity field, the sensor comprising: a ball; a rolling surface describing a generally concave shape on which said ball can roll inside the sensor; a further surface arranged opposite said rolling surface; a first active optical component which is a light emitter; a second active optical component which is a light detector for detecting light emitted by said light emitter; a third active optical component which is a light emitter or is a light detector; a sensor axis; wherein a region within which said ball can move inside the sensor is limited by at least said rolling surface and said further surface, wherein said active optical components are on a first substrate and are arranged outside said region for emitting light through said further surface into said region and detecting light exiting said region through said further surface, respectively, the first substrate being arranged to extend in a direction perpendicular to the sensor axis, wherein a shortest distance between the rolling surface and the first substrate differs for different points along the rolling surface, and wherein the shortest distance between the rolling surface and the first substrate for the different points coincides with or is parallel to the sensor axis.

19. The sensor of claim 18, wherein the rolling surface has a concave shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 a schematized cross-sectional view of a sensor in a first configuration;

(2) FIG. 2 a schematized cross-sectional view of a sensor in a second configuration;

(3) FIG. 3 a schematized cross-sectional view of a plane of a sensor similar to the sensors of FIGS. 1 and 2 indicated by I-I in FIGS. 1 and 2;

(4) FIG. 4 a schematized cross-sectional view of a plane of a sensor similar to the sensors of FIGS. 1 and 2 indicated by II-II in FIGS. 1 and 2;

(5) FIG. 5 a schematized cross-sectional view of a plane of a sensor similar to the sensors of FIGS. 1 and 2 indicated by in FIGS. 1 and 2;

(6) FIG. 6 a schematized cross-sectional view of a substrate of the sensor of FIGS. 3 to 5;

(7) FIG. 7 a schematized cross-sectional view of a substrate of a sensor;

(8) FIG. 8 a schematized cross-sectional view of a portion of a sensor;

(9) FIG. 9 a schematized cross-sectional view of a detail of a sensor;

(10) FIG. 10 a schematized illustration of a rolling surface in a cross-sectional view;

(11) FIG. 11 a schematized illustration of a structured rolling surface in a cross-sectional view;

(12) FIG. 12 a schematized illustration of an averaged surface of the structured rolling surface of FIG. 11, in a cross-sectional view;

(13) FIGS. 13 to 17 schematized illustrations of arrangements of active optical components on a substrate;

(14) FIG. 18 a schematized cross-sectional view of wafers for forming a wafer stack for manufacturing a multitude of sensors;

(15) FIG. 19 a schematized cross-sectional view of a wafer stack for manufacturing a multitude of sensors;

(16) FIG. 20 a schematized illustration of a device comprising a display and a sensor;

(17) FIG. 21 a schematized illustration of the device of FIG. 20 in tilted orientation;

(18) FIG. 22 a schematized illustration of a device comprising a display and a sensor;

(19) FIG. 23 a schematized illustration of the device of FIG. 22 in a different orientation;

(20) FIG. 24 a schematized illustration of a device comprising a sensor;

(21) FIG. 25 a schematized illustration of a structured rolling surface in a cross-sectional view;

(22) FIG. 26 a schematized illustration of a structured rolling surface in a cross-sectional view;

(23) FIGS. 27 to 35 schematized illustrations of arrangements of active optical components on a substrate;

(24) FIG. 36 schematized illustration of apertures in a substrate;

(25) FIG. 37 schematized illustration of apertures in a substrate;

(26) FIG. 38 a schematized cross-sectional view of a portion of a sensor.

DETAILED DESCRIPTION

(27) The described embodiments are meant as examples and shall not limit the invention.

(28) FIG. 1 shows schematized cross-sectional view of a sensor 1 in a first configuration. Sensor 1 comprises a ball 2 present in a region 3 in which ball 2 is movably kept. The ball's mobility is limited by a rolling surface R on which ball 2 can roll and by a further surface F. In the illustrated embodiment, an optional stop surface 9 also contributes to limiting the ball's mobility. Region 3 and ball 2 are present in a first cavity c1 of the sensor 1.

(29) In a second cavity c2, sensor 1 furthermore comprises three or more active optical components two of which are drawn in FIG. 1, namely a light emitter E and a light detector D. As symbolized by the thick arrows in FIG. 1, light emitter E is (or—if more than one is present—light emitters E are) arranged so as to emit light into region 3, and light detector D is (or—if more than one is present—light detectors D are) arranged so as to detect light having left region 3, the light originating at least one light emitter of sensor 1.

(30) Sensor 1 furthermore comprises three substrates p1, p2, p3 and two spacers s1, s2. First cavity c1 is established by and/or enclosed by substrates p2, p3 and spacer s1. Second cavity c2 is established by and/or enclosed by substrates p2, p1 and spacer s2.

(31) In the embodiment of FIG. 1, the shape of rolling surface R is determined by a concave body 6 present on substrate p2. The shape of rolling surface R may be, e.g., spherical or parabolic. In order to let light pass into region R and out of region R (cf. the thick arrows), body 6 is made of a transparent material such as a glass or rather a transparent epoxy or another transparent hardenable polymer material. The latter allow to manufacture body 6 using a replication technique.

(32) In the embodiment of FIG. 1, the shape of further surface F is determined by substrate p3. On further surface F, a reflective or metallic surface 5 may be present in order to provide an improved reflectivity for light, thus strongly diminishing the amount of light exiting sensor 1 through substrate p3. Reflective or metallic surface 5 may be provided in the form of a coating, in particular a metallic coating. Further surface F may be identical with reflective or metallic surface 5, like illustrated in FIG. 1, or may be provided with another coating such as a transparent coating. Reflective or metallic surface 5 might, alternatively to what is illustrated in FIG. 1, be present at the outward face of substrate p3.

(33) The shape of stop surface 9 is determined by spacer s1. The provision of stop surface 9 can make possible to avoid ball 2 getting stuck between rolling surface R and further surface F.

(34) Sensor 1 has a sensor axis A which points in a direction away from rolling surface R and may be an axis of rotational symmetry of rolling surface R.

(35) Substrates p1, p2, p3 are substantially plate-shaped, all having identical lateral outer dimensions describing one and the same rectangular, the term lateral relating to directions perpendicular to the direction of stacking of substrates p1, p2, p3, which again coincides with directions along sensor axis A.

(36) Spacers s1, s2 provide that a distance (along the stacking direction) between neighboring substrates is fixed and well defined, namely amounting to the corresponding extension of the respective spacer, i.e. to the thickness of the respective spacer. Spacers s1, s2 may furthermore be non-transparent, so as to avoid light escaping through the respective spacer and light entering sensor 1 through the respective spacer, wherein it is also possible that only one of the spacers s1, s2 has this property. The non-transparency may be realized by manufacturing the respective spacer of a non-transparent material such as a non-transparent polymer, e.g., epoxy, or by applying a non-transparent coating to the respective spacer.

(37) As described above, spacer s1 may in addition provide the function of a stop surface 9.

(38) Spacer s2 may optionally, as illustrated in FIG. 1, be shaped so as to establish separate compartments (in cavity c2), e.g., one compartment for each active optical component of sensor 1. This can make possible to optically separate the active optical components, in particular when the portions of spacer s2 between neighboring compartments are non-transparent.

(39) Furthermore, it is possible to provide that a spacer is continuous with an adjacent substrate. E.g., spacer s2 may be comprised in substrate p2.

(40) Substrate p1 may substantially be a printed circuit board or an interposer on which the active optical components (such as D and E) of sensor 1 are mounted. On the outwardly facing face of substrate p1, substrate p1 provides electrical contacts 17 allowing to electrically contact the active optical components from outside sensor 1. Electrical contacts 17 may be, e.g., contact pads and/or, as illustrated in FIG. 1, solder balls.

(41) The active optical components may be provided in the form of housed components, in particular surface mount devices (SMD) such as chip scale packages, or as flip chips or wire bound bare dies. Light emitters may be, e.g., LED or OLED or laser diodes; light detectors may be, e.g., photo diodes.

(42) Substrate p2 may be made of a transparent material such as glass or a transparent epoxy or plexiglass or another polymer. In order to better define light paths between cavities c1, c2, substrate p2 may comprise a non-transparent area b (possibly more than one such area b) and at least one transparent area t, typically one transparent area t per active optical component. A non-transparent area may also be referred to as a blocking area since it blocks the propagation of light. The provision of areas b and t makes possible the formation of apertures 8. In the illustration of FIG. 1, the areas b, t are established by providing a structured non-transparent coating on substrate p2. Other ways of doing so will be described below.

(43) The way of functioning of sensor 1 can be described as follows:

(44) One or more light emitters E emit light into region 3, e.g., in a pulsed fashion, and one or more light detectors D detect a portion of that light after it has left region 3. Detection results depend on the location of ball 2 in region 3, wherein gravity force acts on ball 2. In normal measuring mode, ball 2 is present on rolling surface R. The position of ball 2 on rolling surface R is indicative of an amount of tilt of sensor axis A with respect to the direction of gravity and of a direction of that tilt. These magnitudes are usually expressed as polar angle theta and azimuthal angle phi.

(45) Accordingly, the orientation of sensor 1 in a gravity field, e.g., described by theta and/or phi, can be determined from the detection results. At least three active optical components are required for this purpose, wherein the provision of four facilitates the determination of the desired sensor orientation. Certainly, also five active optical components or even more may be provided, but this however usually results in a larger overall size and possibly also in an increased power consumption of the sensor.

(46) FIG. 2 is a schematized cross-sectional view of a sensor 1 in a second configuration. The sensor 1 of FIG. 2 is in many aspects identical with or very similar to the sensor 1 of FIG. 1. Therefore, we shall describe mainly the differences between these sensors and configurations, respectively, and it may be referred to the description of the embodiment of FIG. 1 for the other details and functions. Optional features described in conjunction with FIG. 1 are optional in the second configuration (cf. FIG. 2), too, and vice versa, optional features described in conjunction with FIG. 2 may optionally be provided also in the first configuration (cf. FIG. 1)—each time, of course, only as far as still in agreement with the construction and functioning of the sensor.

(47) Basically, in the second configuration (cf. FIG. 2), the arrangement of rolling surface R and further surface F is turned upside down. The orientation of sensor 1 in which sensor 1 is illustrated in FIG. 2 has been chosen such that sensor axis A points into the same direction as in FIG. 1, because this way, the illustrated orientation of sensor 1 in FIG. 2 is closer to a usual measurement orientation (ball 2 present on rolling surface R due to gravity).

(48) Illumination of region 3 still takes place from cavity c2 to cavity c1 through substrate p2. But further surface F is established by or at substrate p2, and rolling surface R is established by or at substrate p3, in particular, as illustrated in FIG. 2, the shape of rolling surface R is determined by concave body 6 present on substrate p3.

(49) Thus, transparent body 6 does not need to be (but still may be) transparent. A reflective or metallic surface or interface (similar to reflective or metallic surface 5 illustrated in FIG. 1) may be present either on the concave face of body 6 or at the interface between body 6 and substrate p3 (e.g., on the inwardly pointing face of substrate p3) or on the outwardly pointing face of substrate p3. In the latter two cases, concave body 6 should be transparent and in the latter case also substrate p3 should be transparent in order profit from the reflectivity of the reflective or metallic surface or interface.

(50) In the second configuration, light is emitted through further surface F into region 3, and light having propagated from region 3 through further surface F is detected.

(51) Substrate p2 may provide, besides one or more transparent regions, also one or more non-transparent regions and thus also apertures (not illustrated in FIG. 2).

(52) In order to further improve the use of light in sensor 1, one or more lenses or lens elements L may be present on substrate p2. In both configurations, lenses or lens elements may readily be present in cavity c2. Lenses or lens elements in cavity c1, however, are difficult to provide in the first configuration because of the presence of rolling surface R which usually involves the presence of a concave body, and in the second configuration, attention must be paid that such lenses or lens elements are not damaged by ball 2.

(53) Lenses or lens elements L may be provided for one or more of the active optical components of sensor 1. They may be, e.g., diffractive ones or refractive ones and may be collecting ones or dispersing ones, cf., e.g., FIG. 2.

(54) FIGS. 3 to 5 show schematized cross-sectional views of planes of a sensor similar to the sensors of FIGS. 1 and 2. The planes and views are indicated in FIGS. 1 and 2 by I-I, II-II and respectively. Generally, it may be referred to the description of FIGS. 1 and 2 for details. Differences thereto will be explained.

(55) FIG. 3 illustrates a detail of sensor 1 in cavity c1. In the illustrated case, the radial extension (radial extensions with respect to the sensor axis A which in FIGS. 3 to 5 is perpendicular to the drawing plane) of stop surface 9 is less than the outer boundary of concave body 6, the latter being symbolized by a dashed circle in FIG. 3. Spacer s1 is made of a non-transparent material.

(56) FIG. 4 illustrates another detail of sensor 1 in cavity c1. In the illustrated case, four active optical components are provided, namely one light emitter E and three light detectors D. By means of spacer s2, four compartments are created in cavity c1, so as to optically isolate the active optical components from each other. Spacer s2 is made of a non-transparent material. And as may be provided also in the other embodiments, spacer s2 is continuous, more particularly is a unitary part.

(57) FIG. 5 illustrates a detail of sensor 1 in cavity c2. Basically, substrate p2 is shown in FIG. 5. In the embodiment of FIG. 5, no lenses or lens elements are present on substrate p2, at least in cavity c2. But substrate p2 provides apertures 8, more particularly one aperture 8 for each active optical component. These are established by a non-transparent area b and four transparent areas t. The shapes and sizes of apertures 8 do not have to be equal, but may be.

(58) FIG. 6 is a schematized cross-sectional view of a substrate p2 of a sensor illustrated in FIGS. 3 to 5. The cross-sectional plane is indicated by the dashed line in FIG. 5. Portions of substrate p2 are made of a transparent material, and these portions are laterally surrounded by a portion of substrate p2 which is made of a non-transparent material. This is an alternative to the provision of non-transparent coatings as discussed in the description of FIG. 1. Accordingly, apertures 8 are provided by substrate p2.

(59) Such a substrate p2 may be manufactured on wafer level. It may be obtained starting from plate(wafer) of non-transparent material, creating through-holes therein and filling the through-holes with a transparent material, e.g., a hardenable polymer. Alternatively, the through-holes are not filled. However, filling them makes possible to replicate lens elements or other passive optical components on substrate p2.

(60) FIG. 7 is a schematized cross-sectional view of such a substrate p2. One or more lens elements L may be provided on substrate p2, on one or both sides of substrate p2, e.g., in the way illustrated in FIG. 2.

(61) FIG. 8 is a schematized cross-sectional view of a portion of a sensor 1, namely of a portion comprising cavity c1. This portion of a sensor may be used as a part of a sensor in said first configuration such as one as described in conjunction with FIG. 1 or as a part of a sensor in said second configuration such as one as described in conjunction with FIG. 2. In the embodiment of FIG. 8, however, the shape of further surface F is not determined by the respective adjacent substrate (substrate p3 in case of said first configuration, p2 in case of said second configuration), but by a body 7 (also referred to as further body). Further body 7 may in particular describe a generally convex shape, e.g., like illustrated in FIG. 8. Further body 7 may, e.g., be a spherical segment. It may be replicated onto the adjacent substrate.

(62) Furthermore, FIG. 8 illustrates that (concave) body 6 may have, in particular in a region surrounding the rolling surface R, a shape different from the shape illustrated in FIGS. 1, 2, e.g., like illustrated in FIG. 8. The same applies to stop surface 9.

(63) FIG. 8 in addition serves to illustrate a default orientation of the sensor 1 and a default position of the ball 2. In the default orientation, sensor axis A is oriented antiparallel to direction of gravity g. The default position of ball 2 is the position ball 2 has when the sensor 1 has said default orientation—provided the ball is still. Gravity then forces ball 2 into that position in which it has its minimum potential energy on rolling surface R.

(64) FIG. 38 is a schematized cross-sectional view of a portion of a sensor 1, just like FIG. 8, but with a generally concave further surface F. Such a further surface may in fact be considered an additional rolling surface. Incorporating such a sensor portion in a sensor as illustrated in FIG. 1 or in FIG. 2 can result in a sensor which can also be used when oriented upside down. The reflective or metallic surface or interface may be present, e.g., as described for FIG. 2.

(65) Although there is no stop surface present in the embodiment of FIG. 38, it is of course possible to provide one, in particular by designing spacer s1 accordingly.

(66) Furthermore, the further surface F and the rolling surface R may be identically shaped (and oppositely arranged) as shown in FIG. 38, but it is also possible to provide a concave further surface F describing a shape differing from the shape of the rolling surface R.

(67) FIG. 9 is a schematized cross-sectional view of a detail of a sensor 1, namely of a detail comprising cavity c1. FIG. 9 serves to illustrate yet another way of shaping spacer s1 so as to provide a useful stop surface 9. In addition, FIG. 9 illustrates the sensor having an orientation different from the default orientation. In this case, the sensor it tilted by an angle theta of about 30°. For angles greater than approximately this angle theta, polar angle theta cannot be determined anymore by means of the sensor. Distinguishing and determining polar angles by means of a sensor 1 is possible only between 0° and a threshold polar angle. The tilt direction (as indicated by azimuthal angle phi) can, however be distinguished and determined by means of the sensor also for higher polar angles.

(68) The shapes rolling surface R may have can be various ones. Generally, it is a concave shape. It can be a bowl-shape. Elliptic, spherical and polymeric such as parabolic shapes are possible. The rolling surface may, in a general view, describe a portion of a cone or a frustrum of cone. And in a very general view, the rolling surface may generally describe even a concave surface, wherein portions of that concave surface are convex, e.g., similar to the horn of a trumpet or a tuba.

(69) However, it can facilitate determining tilt angles theta when the rolling surface generally describes a shape providing the property that—within a theta measurement range—a resting position of the ball on the rolling surface is stabilized (with respect to movements of the ball towards smaller or larger theta) by the shape of the rolling surface. FIG. 10 is an attempt to describe a corresponding type of rolling surface shapes.

(70) FIG. 10 is a schematized illustration of an embodiment of a rolling surface R for illustrating properties thereof. In addition, FIG. 10 illustrates the case that a body, more specifically a concave body 6, is continuous with the adjacent substrate (p2 in case of the first configuration and p3 in case of the second configuration).

(71) In the embodiment of FIG. 10, the shape of rolling surface R has the property that with increasing distance from the sensor axis A, the steepness of the rolling surface increases, too. More specifically, taking any cross-section through the rolling surface comprising the sensor axis A and taking any two tangent points having different distances to axis A (r1, r2 in FIG. 10), the angle between the sensor axis (in this case neglecting its directivity, taking the angle which is smaller than 90°) and the tangent to the rolling surface in the respective tangent point (α1, α2 in FIG. 10) will be smaller for the tangent point having the larger distance to axis A. In a more mathematical expression: r1<r2 .Math.α1>α2, cf. FIG. 10.

(72) FIG. 11 is a schematized illustration of a structured rolling surface R. In this case, rolling surface R has azimuthal furrows. However, this rolling surface nevertheless describes a generally concave surface. The depth of the furrows is deliberately exaggerated in FIG. 11. Other kinds of structuring are possible, too, e.g., radial furrows (each extending into a different azimuthal direction), or a distribution of bumps over the rolling surface.

(73) FIG. 25 is a schematized illustration of another structured rolling surface R. In this case, rolling surface R has a local convexity 60 which, more particularly, is located in a central position, where axis A intersects rolling surface R. However, this rolling surface nevertheless describes a generally concave surface. Convexity 60 can avoid that the ball assumes a position with polar angle theta=0° (and polar angles near 0°). This can facilitate determining azimuthal angle phi at small angles theta.

(74) FIG. 26 is a schematized illustration of yet another structured rolling surface R. The structuring in this case is more complex than in the other illustrated kinds of structuring. However, this rolling surface nevertheless describes a generally concave surface.

(75) It is furthermore noted that a rotational symmetry of a structuring of a rolling surface is not a necessity, but a possibility.

(76) FIG. 12 is a schematized illustration of an averaged surface R′ of the structured rolling surface R of FIG. 11 as well as of the structured rolling surface R of FIG. 25 and of the structured rolling surface R of FIG. 26, in the same cross-sectional view as FIGS. 11, 25 and 26.

(77) FIGS. 13 to 17 and 27 to 35 are schematized illustrations of arrangements of active optical components on a substrate. The sensor axis is perpendicular to the drawing plane. A small circle symbolizes a light detector, a small square symbolizes a light emitter. The outer (lateral) shape of the substrate not necessarily has to describe the illustrated square.

(78) In FIG. 13, an arrangement with three active optical components is illustrated. FIG. 14 illustrates the arrangement already described in FIG. 4. In FIG. 15, two light emitters and two light detectors are provided. Time multiplexing or wavelength multiplexing may be applied for operating the sensor. E.g., the two light emitters emit light pulses at different times, or they emit light of different wavelengths, each of the two light detector being designed for detecting light emitted from another one of the light emitters. In FIGS. 16, and 17 the light emitter is arranged approximately in the middle between the light detectors, wherein in FIG. 17, five active optical components are provided.

(79) The arrangements of FIGS. 14 to 17 have a high degree of symmetry. It can be advantageous to arrange the active optical components in a less symmetric way. In FIGS. 27 to 29, four active optical components are provided which are not arranged on corners of a rectangle and which describe a pattern having no mirror symmetry. While in FIGS. 27 and 28 two active optical components lie on a straight line passing through the sensor axis (which is located in the middle of the outer rectangle), this is not the case for FIG. 29 in which the position of the sensor axis is indicated by a small dot.

(80) In FIGS. 30 to 35, five active optical components are provided which are not arranged such that four would be located at corners of an rectangle and one in the middle of the rectangle and which describe a pattern having no mirror symmetry. While in FIGS. 30 and 31 three of the active optical components lie on one and the same straight line, this is not the case for FIGS. 32 to 35. And while in FIG. 32, two active optical components lie on a straight line passing through the sensor axis (which is located in the middle of the outer rectangle), this is not the case for FIGS. 33 to 35.

(81) In the illustrated embodiments with less light emitters than light detectors, further embodiments emerge when interpreting a small circle as a light emitter and a small square as a light detector. In these cases, time multiplexing may be applied (the different light emitters) emitting light at different times), or wavelength multiplexing may be applied, e.g., the light emitters emitting light of different wavelengths and the light detector being capable of distinguishing these different wavelengths.

(82) While the above (in particular cf. FIGS. 13 to 17 and 27 to 35) refers to the position of the active optical components, the same may apply for transparent portions or apertures, i.e. these may be positioned in the described ways and locations.

(83) In addition, it can be provided that an aperture for one of the active optical components covers a greater or smaller (lateral) area than at least one other aperture. FIG. 36 illustrates an example. FIG. 36 is a schematized illustration of apertures in a substrate p2. Aperture 8′ established by transparent portion t′ covers a larger area than aperture 8 established by transparent portion t does.

(84) And furthermore, it can be provided that an aperture for one of the active optical components has a different (lateral) shape than at least one other aperture. FIG. 37 illustrates an example. FIG. 37 is a schematized illustration of apertures in a substrate p2. Various exemplary possible (lateral) shapes of apertures are illustrated such as circles, non-circular ellipses, squares, non-square rectangles, slits, triangles.

(85) FIG. 37 is, in addition, an illustration of an example for a non-square outer (lateral) shape of the substrate. Further possible outer (lateral) substrate shapes are, e.g., circles, non-circular ellipses, triangles.

(86) Non-rectangular shapes of substrates can be readily achieved, e.g., when applying laser cutting for separating sensors of a wafer stack.

(87) Also for the boundary of the rolling surface, various shapes may be selected; e.g., circles, non-circular ellipses, squares, non-square rectangles, triangles.

(88) FIG. 18 is a schematized cross-sectional view of wafers for forming a wafer stack for manufacturing a multitude of sensors 1 in the first configuration. Three substrate wafers P1, P2, P3 and two spacer wafers S1, S2 are provided. Hatched areas in FIGS. 18 and 19 indicate non-transparent material or active optical components.

(89) Substrate wafer P1 is a printed circuit board with light emitters and light detectors mounted on it, as well as contact pads or solder balls 17 on the opposite side. Substrate wafer P2 is a generally non-transparent plate having transparent areas t establishing apertures 8. On one side, lens elements are attached to wafer P2, on the other side, concave bodies 6 establishing rolling surfaces R are attached to wafer P2. Substrate wafer P3 may be, as illustrated, generally transparent but provided with a metallization or reflective coating 5, wherein alternatively, it could be generally non-transparent.

(90) Some details concerning properties and possible manufacturing methods of wafer P2 can be inferred from the description given above in conjunction with FIG. 6. Further details concerning properties and possible manufacturing methods of wafer P can be found in WO 2013/010285 A1. Therefore, WO 2013/010285 A1 is herewith incorporated by reference in the present patent application.

(91) FIG. 19 is a schematized cross-sectional view of a wafer stack W for manufacturing a multitude of sensors 1, based on the wafers illustrated in FIG. 18. Stack W may be formed in one or more fixation steps. At a time when spacer wafer S1 is adjacent to substrate wafer P2 (either already fixed thereto or not yet fixed), balls 2 are inserted into cavity 1, on rolling surface R, before substrate wafer P1 is attached to spacer wafer S1.

(92) With the wafers aligned and fixed to each other, e.g., using epoxy glue or another bonding material, the wafer is diced, i.e. separated into singularized sensors 1, in the places indicated in FIG. 19 by the dashed thin rectangles.

(93) It is clear from the present description how the wafers and the manufacturing method have to be adapted in analogy to the above in order to manufacture sensors in the second configuration. Furthermore, it is readily understood how the embodiment illustrated in FIGS. 18 and 19 has to be modified for manufacturing various variants of sensors, e.g., providing no or different lens elements, providing no apertures in wafer P2 and substrate p2, respectively, or realizing these by means of applying coatings, or providing a further surface F having a shape determined by a further (e.g., concave) body 7, and so on.

(94) FIG. 20 is a schematized illustration of a device 100 comprising a display 15 and a sensor 1. The device 100 has its default orientation in FIG. 20. The sensor may be any sensor described in the present patent application.

(95) FIG. 21 is a schematized illustration of the device 100 of FIG. 20, but in tilted orientation. Polar angle theta is different from 0°.

(96) Device 100 may be any device described in the present patent application, e.g., a smart phone or a mobile computing device, or an electronic replacement for a mechanic's level.

(97) Display 15 is controlled by a control unit 16 which again is operationally connected to an evaluation unit 11. The latter two and sensor 1 are mounted on a printed circuit board 18, but might be mounted on different and mutually operationally interconnected printed circuit boards. Light intensity signals 19 from the one or more light detectors of sensor 1 are fed from sensor 1 to evaluation unit 11 for deriving orientation signals 20 therefrom. E.g., a lookup table may be used for deriving the orientation signals 20 from the detected light intensities. The orientation signals 20 are related to or rather indicative of the orientation of the sensor 1 and—provided sensor 1 is fixedly connected to further parts of device 100—of the device 100. In FIGS. 20 and 21, we shall confine to describing the tilt, i.e. the polar angle.

(98) Evaluation unit 11 may be comprised in sensor 1 or not.

(99) In FIG. 20, device 100 and sensor 1 have their default orientation as indicated by the position of ball 2 on rolling surface R. Sensor axis A is antiparallel to direction of gravity g.

(100) In FIG. 21, device 100 and sensor 1 have a tilted orientation with a polar angle theta different from 0° as indicated by the position of ball 2 on rolling surface R. Sensor axis A is antiparallel to direction of gravity g.

(101) The data displayed in display 15 depend on the orientation of sensor 1 and thus on the orientation of device 100 as determined using sensor 1 and evaluation unit 11, as illustrated in FIGS. 20, 21.

(102) FIG. 22 is a schematized illustration of a device 100 comprising a display 15 and a sensor 1. Device 100 of FIG. 22 can be identical to the one of FIGS. 20 and 21, but the relative orientation of sensor 1 and display 15 is different in FIG. 22, as is also symbolized in FIG. 22 by the symbol illustrating sensor 1. The sensor may be any sensor described in the present patent application. The sensor 1 can be identical to the one of FIGS. 20 and 21.

(103) In FIG. 22, sensor 1 and device 100 are tilted along a tilt direction characterized by an azimuthal angle phi1—which is measured relative to a reference tilting direction indicated as “ref” in FIG. 22.

(104) FIG. 23 is a schematized illustration of the device 100 of FIG. 22, but in FIG. 23, device 100 is tilted along a different direction, namely along a tilt direction characterized by an azimuthal angle phi2 (also measured relative to the reference tilting direction indicated as “ref” in the Figs.).

(105) In FIGS. 22 and 23, we shall confine to describing the tilt direction, i.e. the azimuthal angle. Polar angle theta is in both FIGS. 22 and 23 different from 0°.

(106) The orientation of data displayed in display 15 depends on the orientation of sensor 1 and thus on the orientation of device 100 as determined using sensor 1 and evaluation unit 11.

(107) FIG. 24 is a schematized illustration of a device comprising a sensor 1. A controller 35 is provided which may establish, together with sensor 1, at least a part of a control unit 30. Controller 35 and control unit 30, respectively, can control an object 50 in dependence of signals provided by sensor 1. Sensor 1 is fixed with respect to an object 40, such that a tilt or an orientation sensed by sensor 1 is related to or corresponds to an orientation of object 40. Object 40 may be, e.g., a workpiece or a tool. Object 50 may be, e.g., an actuator. Object 50 may be, e.g., a machine, a drive or an engine, or a part of one of these. Object 50 may furthermore act on another object, referenced 45, under control of controller 35 and control unit 30, respectively. Object 45 may be, a workpiece or a tool or a machinery component.

(108) In one interpretation of FIG. 24, the device is control unit 30.

(109) In another interpretation of FIG. 24, the device comprises sensor 1, controller 35 and object 50, wherein the device may be, e.g., a machine, an engine or a drive, or a part of one of these. And the device may optionally comprise one or both of objects 40 and 45.

(110) Sensors described in the present patent application allow to determine an inclination with respect to a vertical direction (direction of gravity force) and/or an azimuthal direction of the inclination axis with respect to an azimuthal reference axis of the sensor. The sensor can provide orientation signals or light intensity signals from which orientation signals can be obtained, wherein said orientation signals are related to or indicative of at least one angle (theta; phi) related to an inclination of the sensor (or of a reference axis of the sensor) with respect to a direction of gravity force.

(111) The polar angle range within which polar angles can be distinguished is usually limited to polar angle range including 0°, and in particular to a polar angle range symmetric about 0°.

(112) The sensors may generally be capable of unambiguously determining tilt orientations (azimuthal angles) within full 360°.

(113) With (at least) three active optical elements, signals outputted by the at least one light detector can allow a determination of an orientation of the sensor, either directly or via determining the position of the ball on the rolling surface. The provision of four active optical components facilitates this.

(114) Even though in Figures of the present patent application, region 3 and even the items present in cavity c1 show a rotational symmetry, this is, in a more general view, merely one possibility and may be designed differently.