Device for optical navigation

Abstract

Device for optical navigation, containing an image sensor array (2) with a plurality of array-like arranged image sensor units (20, 20') each having at least one light-sensitive area and at least one microlens array (3; 3', 3") assigned to the image sensor array and arranged between an object to be imaged (6) and the image sensor array, wherein at least one microlens (30) is assigned to each image sensor unit (20), wherein the microlenses (30) are aligned to each other such that the optical axes of the microlenses are parallel, characterized in that the image sensor array (2) is connected to the at least one microlens array (3, 3, 1, 3") via an optically transparent substrate or transparent intermediate layers (21, 21') and the image sensor array (2) is associated with at least one pinhole array (22, 23) which is arranged between the image sensor array (2) and the microlens array (3, 3', 3"); wherein the microlenses (30) are arranged in at least two (3, 3"), preferably three (3, 3', 3") microlens arrays, wherein at least one microlens of a first microlens array is in line with at least one microlens of a second microlens array, preferably a second and third microlens array.

Description

[0001] The invention relates to a device for optical navigation according to the features of the preamble of the main claim.

[0002] Optical navigation devices are used in data processing systems to translate the movement of an input device, such as a computer mouse, relative to a reference surface or reference object into the movement of a pointer on a display, such as a computer, mobile phone or PDA.

[0003] In optical navigation devices, the so-called tracking surface, or object plane, is projected onto a digital image sensor using a lens. Simultaneously, the object plane is illuminated laterally by a laser or LED with appropriate beam shaping. Images are captured in very rapid succession (1500 to 6000 per second). The successively captured images are correlated, and the relative displacement of the images is used as a measure of the distance and speed of the input device's movement relative to the tracking surface (or vice versa). This is then translated into the movement of a point on the display. A computer mouse with an optical navigation device as described above is shown, for example, in US Patent 6,967,321 B2 or US Patent 7,045,775 B2.

[0004] US Patent 6,256,016 B1 discloses an optical detection system and method for detecting the movement of an optical pointing device in a data processing environment. The system works with any surface that can diffusely scatter a collimated beam from a coherent light source.

[0005] In GB 2 400 714 A1, an imaging system is described that can recognize fingerprints and be used to control a cursor, wherein the detection area is divided into at least two parts, each of which has an independent associated light source. Preferably, the detection area is smaller than a human fingertip in at least one dimension.

[0006] In DE 10 2006 004 802 A1, an image acquisition system with adjacent optical channels, each with an associated microlens with aperture and at least one detector lying in the image plane, is described.

[0007] US patent 2007 / 109272 A1 describes an optical input card. This card is shaped and sized to be removable and slidably inserted into a slot of a portable computer. The optical input card includes an optical navigation sensor, a control panel, and a wireless communication module.

[0008] In JP H10-283114 A, an imaging device with a pen as an input device is described.

[0009] GB 2 329 786 A describes a device for displaying images. This device has a display area with several display elements such as LCDs or CRTs, each of which shows a specific part of the display area side by side in the same direction, with gaps between them.

[0010] WO 2005 / 069 607 A1 describes a digital image recording system with a minimum length of less than one millimeter. This image recording system comprises a microlens array, a detector array, and optionally a pinhole array.

[0011] However, with prior art optical navigation devices, problems arise when the optical structure is further miniaturized: given a specific diagonal of the image sensor and a reduction in the distance between the image sensor plane and the object plane, the outer image areas are at very large angles relative to the optical axis. This degrades the resolution and brightness at the edges of the image sensor.

[0012] The object of the present invention is to provide a device for optical navigation which, even with increasing miniaturization and an increasing reduction in the distance between the image plane and the object plane, also provides good resolution and brightness at the edge of the image sensor.

[0013] The problem is solved by a device according to the features of the main claim. By providing a plurality of lenses, which are configured as a microlens array, and assigning at least one microlens to each image sensor unit of the image sensor, it is possible for the microlens assigned to an image sensor unit to transmit a portion of the object to be imaged essentially "on-axis," i.e., each microlens images only a portion of the object onto the image sensor unit and the light-sensitive surfaces therein. This, in combination with the plurality of array-like image sensor units, results in the object and image portions being essentially directly opposite each other, i.e., it is not an inverted but an upright image of the object.

[0014] Because an object part opposite an image sensor unit lies along the optical axis of the associated microlens, the image sensor can be positioned almost arbitrarily close to the object plane, since the imaging angular range of the microlens of an image sensor unit is very narrow, similar to the compound eye of an insect. With such an arrangement, the resolution is improved, especially at the edge of the image sensor, and the light intensity does not decrease in the area of ​​the image sensor, as there is no strong natural vignetting at the image edge.

[0015] Due to the improved imaging properties of the image sensor, the optical navigation device can be equipped with fewer light-sensitive areas or pixels, since, although each pixel only covers a very small angular range, it can image this range exceptionally well. Therefore, fewer light-sensitive areas are needed to compensate for vignetting. Likewise, it is not necessary to make the spacing between the light-sensitive areas very small (unless a very small image sensor is desired), as the image sensor area can image a substantially uniform object field with virtually no loss of resolution.

[0016] Since conventional image sensors are manufactured using lithographic structuring techniques, at least one microlens array can be applied during the production of the individual image sensor units or the image sensor unit array in such a way that it is associated with and / or rests on and connected to the image sensor arm. In this way, a large number of sensors can be manufactured in a short time. Advantageously, the manufacturing process is carried out on a wafer scale.

[0017] Further beneficial training opportunities are described in the secondary and subordinate requirements.

[0018] It is advantageous if the microlenses are aligned such that their optical axes are parallel to each other. This minimizes the overlap of the object areas imaged onto the individual image sensor units (depending on the image-capable angular range of the microlens), and also makes it easy to generate a 1:1 image of the object field on the image sensor. Advantageously, the microlenses image an object field area onto the image sensor unit that is exactly the same size as the distance between the microlenses or detector pixels themselves. Furthermore, it is advantageous if the optical axes of the individual microlenses are essentially perpendicular to the object plane. This ensures that the object field points captured by the image sensor units are almost equally spaced for each unit.This provides good conditions for ensuring that the lighting conditions of the object field are essentially the same for each image sensor unit, or are not distorted by distance effects of the individual image sensor units.

[0019] As an alternative to the previous designs, the optical axes of the microlenses can become increasingly oblique from the center of the image sensor to the edges, i.e., that, taking the optical axis of a microlens in the center of the image sensor as a reference point, the surrounding optical axes of the microlenses are slightly inclined outwards or inwards. This oblique design of the optical axes allows for a deviation from a 1:1 image and enables the projection of a smaller object field onto a larger image sensor (with an inward inclination of the optical axis) or a larger object field onto a smaller image sensor (with an outward inclination of the optical axis). However, with increasing inclination of the optical axes, effects such as astigmatism or field curvature must also be taken into account in the design of the microlenses, which is already known in the prior art.In particular, it must be ensured that, at the desired working distance, the object field areas assigned to the individual image sensor units are contiguous and that no gaps exist between them, meaning that the edge length of an object field area assigned to an image sensor unit is greater than the distance between the microlenses. According to the invention, the working distance between the object plane and the image sensor is on the order of 0.1 mm to 1 mm or 0.1 mm to several meters.

[0020] It is particularly advantageous if the microlenses are aligned and designed in such a way that the object field sections of adjacent microlenses do not overlap, i.e., are disjoint from one another. Even more advantageously, there is no gap between the object field regions of two adjacent microlenses, so that the object field in its entirety can be transmitted to the image sensor without redundant information. The microlenses image the object field regions onto the light-sensitive surfaces, which can be significantly smaller than the imaged object region without compromising the global 1:1 imaging.

[0021] It is further advantageous if an image sensor unit is connected to at least one microlens via an optically transparent substrate, whereby the substrate can be made of the same material as the microlens, but this is not mandatory. This results in fewer optical transition surfaces, which simplifies the calculation of the beam path and also makes the arrangement of the microlenses on the image sensor units easier. In this way, reflections are avoided, leading to improved light transmission.

[0022] A further advantageous embodiment of the device is achieved by arranging at least one (transparent) pinhole aperture in an opaque material (or layer) between a microlens and the light-sensitive surface of the image sensor unit. The pinhole aperture provides an additional mechanism to focus only the light from the object field portion to be imaged onto the light-sensitive surface associated with that portion. Light incident on the microlens from other directions, which could otherwise fall onto another light-sensitive surface associated with a neighboring image sensor unit, is suppressed (or absorbed) by the pinhole layer, thus preventing crosstalk between adjacent image sensor units. In the case of 1:1 imaging (perpendicular optical axes), the pinhole apertures are centered with the respective lenses and detector pixels.

[0023] One possible embodiment of the microlens arrangement with respect to the image sensor units is in which the microlenses are arranged in a plurality of stacked microlens arrays, preferably two, more preferably three. In each case, a microlens of the first microlens array is aligned with a microlens of the second or third microlens array such that the microlenses are in alignment. The arrangement of the microlenses as a Gabor superlens is particularly advantageous. In this variant of the optical navigation device, an object field section opposite an image sensor unit is imaged onto it. However, not only the microlenses located in the line connecting the object field section and the image sensor unit contribute to the imaging of the object field section, but also microlenses adjacent to these microlenses.By appropriately arranging multiple microlens arrays, several optical channels formed by the microlenses simultaneously contribute to imaging a portion of the object field onto a light-sensitive surface. The advantage is that such a microlens arrangement is significantly more light-sensitive than one using essentially only a single microlens array, since here not just one optical channel, but a multitude of optical channels contribute to the formation of a portion of the object field onto the light-sensitive surface.

[0024] Particularly advantageous is the arrangement of the microlens arrays such that a spacer array with apertures transparent in the direction of the optical axis is placed between a first (or second) microlens array and a second (or third) microlens array, whereby adjacent microlenses are largely optically isolated from each other perpendicular to the optical axis of the microlenses. In this way, unwanted crosstalk within the channels is essentially prevented. In this variant, the correct overlap of multiple partial images is intended to achieve the increased light intensity. Light from the second lens of one channel should not enter the third lens of the adjacent channel of the microlens array below, which can be achieved by optically dense walls between these microlens arrays. At the same time, the first and second microlens arrays are fixed at the desired distance from each other.

[0025] Another alternative microlens arrangement for the image sensor is to assign only one microlens to each image sensor unit, where each image sensor unit preferably has a single light-sensitive area. This arrangement essentially corresponds to the apposition principle, except that, unlike an insect's eye, the individual lenses are arranged in a plane and not along a curved surface. The arrangement is particularly advantageous if the optical axis of a microlens is essentially perpendicular to its associated light-sensitive area of ​​the image sensor unit. The advantage of such a microlens arrangement lies in its very simple design, allowing this navigation sensor to be manufactured quickly and cost-effectively, for example, using lithographic and replication technologies on a wafer scale.

[0026] It is particularly advantageous if the optical navigation device has an incoherent or coherent optical light source associated with the image sensor, such that the light source illuminates the object field to be imaged on the image sensor. This is advantageously done in reflected light mode, i.e., from the same hemisphere relative to the tracking surface (i.e., the object field) in which the imaging system is located. In this context, a spectrum of the light source is particularly advantageous that lies in the visible range between 350 and 759 nm, or in the near-UV range (up to 200 nm), or in the near-infrared range (up to 1300 nm). This is especially necessary when uniform illumination of the object field to be imaged by natural light sources is not possible.In the case of incoherent illumination, a light-emitting diode (LED) is advantageously used, mounted laterally at a very small angle to the object field to be imaged. This ensures that the object field's structure results in shadows, which can then be imaged onto the image sensor by the microlenses. In this way, image information or modulation can be applied to an otherwise virtually textureless object plane. In the case of coherent illumination, a laser diode is advantageously used, where an oblique incidence of the illumination is tolerable, since coherent scattering generates a speckle pattern above the object plane, which can be detected by the image sensor. It is important to note that the object plane of the arrangement is no longer the tracking surface, but rather the speckle field backscattered or generated by it.The speckle field is formed by interference of neighboring scattered bundles, typically at a distance of about 1 mm from the tracking surface.

[0027] To achieve the most efficient illumination using the light sources, the light source can be directed onto the object field using deflecting optics or collector optics. It is also advantageous to integrate optical fibers into the image sensor, for example, between the individual light-sensitive surfaces, which couple the light towards the object field being imaged.

[0028] The light source and the image sensor microlens assembly are preferably arranged on a common substrate, so that the substrate can be installed and removed as a single module. The substrate can be an electronic component, such as a printed circuit board. In this way, the illumination of an object field can be determined by the arrangement of the illumination relative to the image sensor.

[0029] Advantageously, the image sensor has a surface area of ​​0.25 µm. 2 up to 10 mm 2 or between 100 and 10,000 image sensor units, preferably between 100 and 1,000 image sensor units. In this way, despite the significant miniaturization of the image sensor, good results can already be achieved when adapting to different object field sizes.

[0030] Further features are listed in the dependent claims.

[0031] The inventive device for optical navigation will now be explained with reference to some exemplary embodiments and figures. These show Fig. 1 Device according to the invention for optical navigation with image sensor microlens array and radiation source; Fig. 2 Image sensor with microlens array designed as an apposition image sensor; Fig. 3 image sensor with Gabor super lens.

[0032] The Fig. Figure 1 shows an input device 1 according to the invention, such as that which may be implemented in a computer mouse or a remote control, which has an image sensor 2 on which a microlens array 3 is mounted. Furthermore, a light source 4 in the form of an LED is provided, wherein both the light source 4 and the image sensor 2 are arranged on a support 5. Directly below the microlens array 3 is the object field 6, which is scanned by the input device 1.

[0033] A pattern located in the object field 6 is illuminated by the light source 4, so that a point-by-point image is formed on the image sensor 2 by means of the microlens array 3. Alternatively, a coherent light source such as a laser diode can be used instead of an LED. In this case, no shadow is generated on the object field 6, but rather a speckle pattern produced by interference of the coherent light, which is visible above the tracking surface and can be detected by the image sensor 2.

[0034] Typically, the object field 6 has the same size as the image sensor 2 or the microlens array 3, resulting in a 1:1 image. This has the advantage that the microlens array 3 can be arranged on the image sensor such that the optical axes of the microlenses are essentially perpendicular to each individual image sensor unit of the image sensor 2. In particular, this means that the portion of the object field 6 that is imaged onto an image sensor unit of the image sensor 2 lies directly below that unit. Furthermore, this arrangement ensures that the image sensor units are positioned at the same distance from the portions of the object field 6. In the illustration shown here, the distance h between the object field and the image sensor is between 0.5 mm and 2 mm.

[0035] An electronic component can serve as a carrier, which - after the image sensor and lighting have been applied to it - is simply plugged onto a device, e.g. a mouse.

[0036] The following section briefly describes the functionality of the input device 1 according to the invention. The carrier 5 is moved across the plane in which the object field 6 lies, so that the image sensor perceives and displays different sections of the plane within the object field. The image sensor rapidly captures images of the depicted object field, compares these with previously captured images, and can thus determine whether the input device has moved left, right, forward, or backward. Of course, the reverse is also possible: it is not the input device 1 that moves, but rather the underlying plane. As an example, a navigation sensor according to the invention, which is used as an eye tracker, is mentioned here. This sensor is located in a fixed position and records the movements of the eye, which is constantly moving.Eye movement can be translated into moving a pointer or operating a robot arm. Similarly, the navigation sensor in a remote control can be used, with movements of the remote control being translated into movements of a cursor on a monitor or television.

[0037] The optical navigation sensor shown here in input device 1 is ideally suited for wafer-scale manufacturing. This enables cost-effective production and assembly. Both the image sensor 2 and the microlens array 3, as well as their interconnection, can be manufactured at wafer scale. This includes the assembly of the individual components into the optical navigation sensor. Furthermore, the individual sensors can be separated using wafer saws (since a single wafer can accommodate significantly more sensors). Singulation is therefore almost the final production step; however, due to self-alignment effects, it may also be advantageous to perform the assembly element by element using simple alignment and assembly machines.

[0038] The following refers to two variants of the image sensor microlens arrangement which are particularly relevant to the invention.

[0039] In Fig. Figure 2 shows an image sensor microlens arrangement with an apposition lens 100. Together, they form an optical navigation sensor. The actual image sensor 2 has a plurality of image sensor units 20', which contain photodiodes or detection pixels. A radiolucent substrate 21 made of glass, porcelain, or plastic is applied to the image sensor arrangement, and the substrate contains a first pinhole array 22 and a second pinhole array 23. Above the first pinhole array 22 is the microlens array 3 made of glass or plastic, which is connected to the substrate 21. The microlens array 3 contains a plurality of microlenses 30, with each microlens 30 corresponding to exactly one detection pixel, i.e., a light-sensitive area of ​​the image sensor unit 20. The plurality of microlenses 30 has a total width 200, which is the same width as the object field 6 to be imaged.The optical axis 31 of a microlens 30 is perpendicular to the light-sensitive surface 20. This means, in particular, that the part 60 of the object field 6 is imaged onto the directly opposite detector pixel.

[0040] Two adjacent microlenses, e.g., 30 and 30', are designed such that the portions 60 and 60' of the object field 6, which the microlenses image onto the light-sensitive surfaces behind them, do not substantially overlap, and no gap is formed between them. This ensures that the entire object field 6 is resolved into portions (e.g., 60, 60') and imaged onto the image sensor units, with each image sensor unit having exactly one pixel. Thus, an upright image is generated on the image sensor 2, in contrast to a single large lens, where an inverted image is produced according to the laws of geometric optics.

[0041] In the Fig. The optical axes 31 of the microlenses 30 are parallel to their neighboring lenses. Because opposite parts of the object field 6 are imaged onto the individual light-sensitive surfaces of the image sensor 2, only light rays from a small angular range fall on the light-sensitive surface 20. This will be explained using the microlens 30, the part 60 of the object field 6 it images, and the underlying light-sensitive surface 20.

[0042] Due to the imaging by the microlens array 3 and the attenuation of the edge and intermediate regions of the microlens array by the first pinhole array 22, only certain light rays can reach the light-sensitive area. This applies particularly to the light rays of part 60 of the object field 6, when the additional pinhole layer 23 prevents crosstalk from one lens to the detector pixel of the adjacent channel. This is illustrated by the principal rays of the marginal bundles 32, which represent the path through the microlens center (or, in the principal plane, the cardinal point). These indicate that the object area detected by a channel corresponds exactly to the photodiode size projected onto the object plane via the image and object distance of the microlens. It should be noted that the marginal bundles are also focused on the pixels.However, only the marginal rays for the central bundle and the principal rays for the marginal bundles are shown. The path of the marginal rays (the focusing) can be derived from the path of the central bundle. The marginal rays 33 for perpendicular incidence show the imaging effect of the microlens and how the pinhole arrays 22 and 23 only allow certain areas to pass through, thus ensuring that the sub-areas of the object field 6 adjacent to part 60 are covered by adjacent image sensor units.

[0043] Alternatively to the one in the Fig. In the microlens arrangement shown in Figure 2, the optical axes 31 can be slightly inclined towards the edge of the sensor, i.e., from the center to the left and right edges, so that a global 1:1 image is no longer present and the imaged object field 6 is larger than the image-relevant part 200 of the image sensor 2. In this case, however, it must be ensured that at the desired working distance, the object field area assigned to a single microlens is directly adjacent to the object field area of ​​a neighboring lens, which means that the edge length of an object field area assigned to a microlens is greater than the distance between the microlenses. As shown in Figure 2, the optical axes 31 can be slightly inclined towards the edge of the sensor, i.e., from the center to the left and right edges, so that a global 1:1 image is no longer present and the imaged object field 6 is larger than the image-relevant part 200 of the image sensor 2. In this case, however, it must be ensured that at the desired working distance, the object field area assigned to a single microlens is directly adjacent to the object field area of ​​a neighboring lens, which means that the edge length of an object field area assigned to a microlens is greater than the distance between the microlenses. Fig. As shown in Figure 1, the working distance or object distance according to the invention is on the order of 0.1 - 1 mm or, more generally, as an optical navigation sensor, 0.1 mm to several meters.

[0044] Alternatively, one of the pinhole arrays 22 or 23 can be omitted. This slightly reduces the image quality, but the main advantage of the arrangement—that the microlenses project an opposite portion of the object field onto the light-sensitive area—remains. Specifically, this means that the edge of the object field 6 is imaged by different microlenses than the central portion of the object field 6. The central portion, however, is imaged almost perpendicularly onto at least one microlens and the associated image sensor unit.

[0045] By using a suitably selected number of aperture arrays in an axial arrangement and appropriately chosen layer thicknesses of transparent intermediate layers, such as layer 21 in this case, crosstalk between adjacent channels, which would otherwise lead to stray light and thus a reduction in the signal-to-noise ratio, is largely suppressed. At the same time, the size and position of the apertures should be such that vignetting of the desired useful light, especially for the edge beams of a single optical channel, is minimal.

[0046] In the variant of Fig. In 2 and its related variants, the light-sensitive areas 20 should be significantly smaller than the channel spacing to achieve a meaningful resolution. However, this leads to a reduced fill factor of the detector pixels in the image sensor and a comparatively reduced light intensity. It is advisable not to use densely packed large photodiodes covered with small apertures, but rather the photodiodes should be appropriately small from the outset, and the space between the photodiodes should be used for electronic circuits for efficient image readout, signal amplification, increased sensitivity, improved signal-to-noise ratio (e.g., through correlated double sampling), or, in particular, for image preprocessing such as contrast calculation, contrast direction measurement, and image shift determination. Alternatively, if the Fig. Since several pixels are assigned to a single microlens in the image sensor shown in the 2, the respective partial images taken must be rotated by 180°, as this results in an inverted, non-upright image within a single image sensor unit.

[0047] Advantageously, the navigation sensor of the Fig. 2. The components are manufactured at wafer-scale. This includes the integration of the image sensor with the microlens array. Furthermore, the microlenses undergo UV replication in polymer on a glass substrate, which is then bonded to the image sensor. Alternatively, the entire or partial lens assembly is hot-embossed and subsequently bonded to the image sensor, or the lens assembly is directly built up / assembled layer by layer onto the image sensor using lithographic techniques and replication. Since multiple image sensors can be accommodated on a single wafer, they are later separated using a wafer saw, but advantageously only after completion of the entire layer build-up. After separation of the modules (this can be just the optics or together with an image sensor), the sides must be blackened, for example with absorbing epoxy, to prevent lateral coupling of stray light through the substrate end faces of substrate 21.For a wafer-scale connection to the image sensor, backside contacting via through-silicon vias is advantageous, as otherwise the optical areas would have to be designed smaller than the areas of the image sensor 2 in order to keep the bonding pads clear for contact. A pedestal-like structuring of the spacer layer formed by the substrate 21 onto the active area of ​​the image sensor then prevents the image sensor wafer from being damaged on the front side when sawing the optics.

[0048] In the Fig. Section 3 presents an alternative arrangement that can be used in optical navigation. The image sensor microlens arrangement shown here, with the Gabor Superlens 101, is significantly brighter than the variant of the Fig. 2, since several adjacent optical channels (which are formed here from the aligned microlenses of the microlens arrays 3, 3' and 3") contribute simultaneously to the formation of an image point. In the representation shown here, the distance of the image sensor 2 from the object field 6 is approximately 600 µm. The setup is analogous to previously known Gabor superlenses, but preferably without the difference in the center distances of the microlenses that is otherwise common there, which is sufficient for the imaging task at hand.

[0049] In the Gabor superlens with three microlens arrays 3, 3', 3'', the microlens array 3 generates an intermediate image, which is transferred by the microlens array 3'' to the image plane lying in the plane of the light-sensitive surfaces. The microlens array 3' functions as a field lens array. Preferably, a 1:1 image is generated within the microlens array arrangement 3, 3', 3''. The image plane usually contains several light-sensitive surfaces, although typically only one light-sensitive surface is located in the image plane of a channel.

[0050] A substrate 21, for example made of a translucent polymer, is mounted on the image sensor 2. A microlens array 3" is arranged on this substrate. A spacer 34 is located on the microlens array 3". This spacer is translucent in the direction of the optical axes of the channels but opaquely separates adjacent optical channels. Another microlens array 3' is arranged on the spacer 34 and is connected to a substrate 21' and a third microlens array 3. The thicknesses of the microlens arrays 3, 3', 3'' and the substrates 21, 21' and the spacer 34 are chosen such that, as in the variant of Fig. 2. A portion 60 of the object field 6 is imaged onto an opposite image sensor unit 20. However, not only the microlenses located in the direct line of connection between portion 60 of the object field 6 and the image sensor unit 20 contribute to this, but also microlenses of adjacent channels. The images are upright and superimposed due to the optical design.

[0051] Alternatively, a setup with only two microlens arrays is also conceivable, whereby the image plane of the microlens array closest to the object field, the so-called intermediate image plane, is the object plane of the second microlens array. This is as described in the Fig. The additionally attached third microlens array shown (here given by the microlens array 3') is suitable to image all light from the apertures of the lenses of the first microlens array 3 in the apertures of the lenses of the second microlens array 3".

[0052] The navigation sensor shown here displays an upright image to ensure that the various sub-areas of the object field 6 are transferred, for example, 1:1 in the correct position and orientation (i.e., in overlap) to the individual photodiodes 20. An optical channel is formed by the aligned microlenses of the microlens array 3, 3', 3'' (i.e., several optical channels are located next to each other), and a sub-area of ​​the object field 6 is transmitted simultaneously through several channels. However, the sub-areas of the object field 6 that are transferred to different light-sensitive surfaces can be disjoint from each other. (Comment: If I understood your comment correctly, then the above should now be correct.)

[0053] The optically isolating spacer 34 prevents unwanted crosstalk between the second and third lenses of adjacent channels. The image sensor and / or downstream electronics (not shown here) process subsequently acquired images into a pointer movement, for example, on a display. The intermediate image distance, and thus substrate thickness 21', and the image distance, and thus substrate thickness, of the second substrate 21, as well as the distance between the second and third lenses, result from the focal lengths and focal length ratios of the microlenses, their axial spacing, and the distance of the object field or a speckle field in the case of coherent illumination to the microlens array 3, as well as the size of the channel spacing for suppressing crosstalk from the first lens of one channel to the second lens of the adjacent channel through the first substrate 21'.

[0054] In the version shown here, the lens pitches are identical, resulting in a 1:1 image. However, these pitches can also differ, which can then result in a magnified or reduced image, depending on whether the lens array with the larger pitch is positioned on the image-side or object-side of the optics and on the ratio of object to image distance. This results in inclined optical axes, which connect the object and its components via the lens channels.

[0055] The optically insulating spacer 34 has the form of a sieve. It consists of a perforated matrix in a plate which is between 10 µm and 500 µm thick, wherein the diameter of the holes is smaller than their spacing and the resulting vertical struts are opaque either by the material of the plate or by a subsequent coating, so that no optical connection occurs between adjacent channels.

[0056] Furthermore, the spacer aids in the self-centering of the two substrates and the microlens arrays mounted on them, enabling very simple yet precise alignment of the optical elements. The pitch and arrangement of the holes are identical to those of the mounted microlens arrays. Consequently, the diameters of the holes are smaller than or equal to those of the lenses, allowing the lenses to snap into the holes on both sides of the substrates, providing a preferred method for lateral and axial adjustment. The thickness of the plate is determined by the required distance between the 3' microlens array, which acts as a field lens, and the second 3" microlens array, taking into account the necessary adhesive thickness. The assembly can be mounted using simple pick-and-place robots.

[0057] In this arrangement, there is no universally valid, fixed assignment of an optical channel to an underlying detector pixel, since a regular, closed image is generated. This means that even with a square arrangement of the detector pixels, the arrangement of the optical lens channels can, for example, also be hexagonal to achieve the highest possible packing density of the channels and thus the highest possible light intensity. Accordingly, the pixel size and number of pixels of the image sensor do not need to be matched to the number and size of the channels. Therefore, in this variant of the Fig. 3 a conventional image sensor 2 with densely packed detector pixels can also be used.

[0058] The size of the intermediate image is essentially defined by the thickness of the substrate 21'. Advantageously, the size of the intermediate image should be as small as possible compared to the channel spacing, so that an object point can be transmitted simultaneously by as many optical channels as possible. This means, in particular, that the focal length of the first microlens array 3 should be as short as possible. The radii of curvature of the lenses in the three lens arrays can generally differ. Even then, with a suitable choice of spacing and focal length ratios, a 1:1 image within a channel is still achieved. However, the pitch of the three lens arrays must be the same for a global 1:1 image. This is achieved using the variant of Fig. 3 also a large “super pupil” which ideally can extend almost over the entire microlens array, thus effectively providing a lens diameter contributing to object point transmission that corresponds to that of a conventional miniature lens, without having to accept an oblique beam path for the outer object areas.

[0059] At the object's edge, different channels contribute as central and marginal channels than in the object's center; however, due to the array-like continuation, there is always a channel that transmits the object point at almost perpendicular incidence, and the neighboring channels, still located in the superpupil, are then transmitted at slightly increased angles.

[0060] Preferably, the overall system is achieved by stacking at wafer-scale or by element-by-element mechanical self-adjustment of only the optics, followed by a rough lateral alignment to the image sensor and bonding. Separating the modules necessitates blackening the sides, for example with absorbent epoxy, as already described in Fig. 2. The spacer is manufactured using a die-cutting or etching process, or by drilling. A lithographic structuring process, such as applying SU8 photoresist to a substrate, is also possible. The resulting perforated foil is then blackened. If the holes cannot be structured through the substrate, the perforated plate or foil can be fully opened and the end faces can be polished on the reverse side to achieve the necessary surface quality. Reference symbol: 1 Input device 2 image sensor array 3, 3', 3'' microlens array 4 Radiation source 5 carriers 6 object field 20 image sensor unit 21, 21' Radiation-permeable substrate 22 First pinhole array 23 Second aperture array 30 microlens 31 Optical axis 32 main rays 33 marginal rays 34 spacers 60, 60' object field section 100 image sensor with apposition lens 101 image sensor with Gabor super lens 110 First beam path 120 Second beam path 130 Third beam path 200 field of view 340, 340' partition

Claims

[1] Device for optical navigation, comprising an image sensor array (2) with a plurality of array-like arranged image sensor units (20, 20') each having at least one light-sensitive area and at least one microlens array (3; 3', 3") assigned to the image sensor array and arranged between an object to be imaged (6) and the image sensor array, wherein at least one microlens (30) is assigned to each image sensor unit (20), wherein the microlenses (30) are aligned to each other such that the optical axes of the microlenses run parallel, characterized by , that the image sensor array (2) is connected to the at least one microlens array (3, 3, 1, 3") via an optically transparent substrate or transparent intermediate layers (21, 21') and the image sensor array (2) is associated with at least one pinhole array (22, 23) which is arranged between the image sensor array (2) and the microlens array (3, 3', 3"); wherein the microlenses (30) are arranged in at least two (3, 3"), preferably three (3, 3', 3") microlens arrays, wherein at least one microlens of a first microlens array is in line with at least one microlens of a second microlens array, preferably a second and third microlens array. [2] Device for optical navigation according to one of the preceding claims, characterized by , that the microlenses (30) are designed such that an object section (60) imaged on a first image sensor unit is disjoint from an adjacent object section (60') imaged on a second image sensor unit. [3] Device for optical navigation according to claim 1 or 2, characterized by, that the first microlens array produces an intermediate image which is mapped onto a common image plane by the second microlens array, with another microlens array being used between the first and second microlens arrays as a field lens array. [4] Device for optical navigation according to claim 3, characterized by , that the arrangement of the microlenses forms a Gabor superlens (101). [5] Device for optical navigation according to any one of the preceding claims, characterized by that the individual optical channels between the image sensor unit and the microlens are optically isolated. [6] Device for optical navigation according to one of the preceding claims, characterized by , that the at least one microlens array (3, 3', 3") and the image sensor array (2) are connected to each other at least partially via spacers (34). [7] Device for optical navigation according to one of the preceding claims, characterized by , that the image sensor array is associated with at least one incoherent or coherent optical radiation source (4) and the radiation source (4) illuminates the object (6) to be imaged. [8] Device for optical navigation according to claim 7, characterized by , that the optical radiation source (4) is a light-emitting diode or a laser diode. [9] Device for optical navigation according to one of claims 7 or 8, characterized by , that the radiation source (4) irradiates the object directly or by means of a deflecting optic and / or a collector optic or by means of optical fibers coupling out towards the object. [10] Device for optical navigation according to any one of claims 7 to 9, characterized by , that the image sensor array (2) and / or the radiation source (4) are arranged on a support (5). [11] Device for optical navigation according to claim 10, characterized by , that additional substrate layers, preferably made of silicone and / or PCB and / or plastic, are arranged between the carrier (5) and the image sensor array (2) and / or the radiation source (4). [12] Device for optical navigation according to any one of the preceding claims, characterized by , that the image sensor (2) has an area of ​​0.25 µm 2 up to 10 mm 2 owns. [13] Device for optical navigation according to one of the preceding claims, characterized by , that the image sensor (2) has from 100 to 10,000, in particular from 100 to 1,000 image sensor units. [14] Device for optical navigation according to one of the preceding claims, characterized by, that the overlaps of the object areas mapped onto the individual image sensor units are small and the optical navigation device produces a 1:1 image of the object field on the image sensor. [15] Device for optical navigation according to claim 14, characterized by that the pinhole apertures of the pinhole array are centered with the respective lenses and image sensor units. [16] Device for optical navigation according to any one of the preceding claims, characterized by , that the microlenses project an object field area onto the image sensor unit which is exactly the same size as the distance between the microlenses or detector pixels. [17] Device for optical navigation according to one of the preceding claims, characterized by that the object field has the same size as the image sensor array and / or the microlens array. [18] Device for optical navigation according to any one of the preceding claims, characterized by, that two adjacent microlenses of the microlens array are formed, that parts of the object field which the microlenses image onto light-sensitive surfaces behind them do not essentially overlap and that no gap is formed between them. [19] Device for optical navigation according to one of the preceding claims, which is configured for a working distance between an object plane and the image sensor array on the order of 0.1 mm to 1 mm. [20] Input device for a data processing system, preferably a computer mouse or a remote control or a console control device, characterized by that a device for optical navigation according to one of the preceding claims is provided. [21] Use of an optical navigation device according to one of the preceding claims for controlling a cursor on an image output device by means of a relative movement between the image sensor and the object to be imaged.

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