DE102016004673B4 - Drive system for a freely rotatable camera - Google Patents

Abstract

Drive system for a freely rotatable camera, which has an image sensor (1) and optics accompanying elements (2) and is provided within a camera carrier device, the drive system being coupled to the preferably spherical camera, and the drive system having at least one drive element which has a band in the form is a spiral (5), and the band is coupled at one end to the camera and at the other end to the camera carrier device, and the band consists of at least two layers, one layer forming the outer surface and the other the inner surface of the band, at least one of which is an electroactive polymer coating (40) which expands under tension and thereby generates a torque, and the electroactive polymer coating (40) is coupled to power lines in order to supply them with power, and the at least one drive element is an evaluation unit or Control has the electroactive polymer coating (40) puts tension and thereby actively expands it, characterized in that the band consists of metal or an alloy, the electroactive polymer coating (40) being applied on one side, and the metal or alloy in the spiral (5) is electrically isolated from the electroactive polymer coating (40).

Description

The invention relates to a drive system for an image sensor and its optical accompanying elements (practically image recording devices and cameras of all kinds) within a device that is equipped with a camera. The drive system is able to rotate the image sensor and its optical elements (its complete lens system) in almost any direction and thus also to detect moving targets without the need to cover the entire housing of the device in which the camera is installed , to move.

The drive system is used in all devices that have an image sensor, e.g. Digital cameras of all kinds (video cameras, 35mm cameras, digital single-lens reflex cameras), notebook, smartwatch (a kind of wristwatch with PC-like or smartphone functions), tablet PC, as well as webcams, drone cameras, vehicle cameras or surveillance cameras, data glasses, mobile phones, etc. a. Smartphones, endoscopy cameras, medical devices of all kinds that have a camera, etc. The drive system is able to move or rotate the camera sensor and its optics in any direction in a controlled manner in all of these devices. The entire carrier device of the camera is not moved or rotated, only the image sensor with its optics inside the carrier device, almost like a human eye.

In particular, the system is perfect for small devices that have a camera, such as Mobile phones (smartphones), tablet PCs, notebooks, netbooks, data glasses, smart watches, unmanned remote-controlled drones, robots, endoscopes, etc.

Almost every tablet PC, notebook or mobile phone, especially a smartphone, has a built-in camera these days, usually even two. Two cameras are sometimes necessary to take pictures of the surroundings or make videos with one and to enable a video conversation via the other camera via providers (e.g. Facebook, Skype, Tanga, Viber, X8, Cobra, Aquila, etc.). Because the installation of a camera is complex and also because the parts are not cheap, a weaker, inferior front camera and a better rear camera are usually installed. The installation of two cameras has other disadvantages. The space in a smartphone becomes quite narrow for further extensions or technical innovations. The battery usually takes up the most space in a smartphone. But the cameras and their controls are not to be neglected either. The installation of a weaker, inferior front camera has other disadvantages. The transmitted video quality via video chat programs is pretty bad via the front camera. While the rear camera can usually take good photos or videos, the front camera is usually inferior. Because the Internet is getting faster and faster these days, it is in the interest of users to transmit pictures or videos with high quality. Since many people also take photos of themselves (so-called selfies), a good image quality of the front camera is desirable. An image sensor is used for film, video or image recordings on a mobile phone, which also determines the advertised image resolution. Due to the small dimensions of the optical lens and very small sensors, the image acquisition is particularly susceptible to image noise. Even in good lighting conditions - compared to conventional digital cameras - only moderately good pictures can be generated. It is also clear that with such extremely small image sensors and also small lenses, only little light from the surroundings or from the image motif arrives and the missing light information is compensated for by electrical means. In addition, the sensor microcomponents are arranged in a very narrow space, which leads to field interactions and no “clean transport” can be guaranteed with the data signals, which in turn leads to image noise. The images only get better with improved organic, photo and sensor technology.

The installation of two cameras in a smartphone requires not only the installation of two camera sensors or image sensors, but also the optics accompanying elements that an image recording optics system requires, such as optical lenses, image correction elements, image stabilizers and a controller. The software must also be able to control the two cameras independently, which also makes the operation of a smartphone more or less complicated.

If the invention is installed in a smartphone (mobile phone with PC properties), it virtually completely replaces the second camera. Because it can be rotated electrically, it can take pictures or record video from both the back and the front. Especially for small devices, such as Flight drones, data glasses, tablet PCs, the invention is perfectly suitable.

There are numerous drive systems that are suitable for moving a camera. Mostly, electric motors (usually stepper motors) are often used with small gears that can pivot the camera back and forth. However, the electric motors and gears have some disadvantages. These are not infinitely small, are correspondingly heavy, can be susceptible to interference (e.g. dust or moisture), are not absolutely silent and also not sufficiently fast if the camera is to be swiveled quickly.

The registration GB 2 439 346 A describes a suspension (gimbal) for a ball, which is purely electromagnetic without mechanical contact. There, a ball is held in an electromagnetic cage, which can then be rotated. A camera can be built into the ball. Both the rotatable body and the stator sheath are equipped with a large number of electromagnetic coils that have to be supplied with current. The interactivity between the fields of the coils creates a rotary movement. The camera sensor and the electromagnets are coupled to electrical lines, which in turn are coupled to the stator, which leads to susceptibility to the movement of the camera and the electromagnets. This arrangement is too complicated and uneconomical for small devices such as cell phones, webcams, vehicle cameras, or drone cameras. Numerous methods are described for rotating a ball.

The registration JP H08-272 446 A. describes a device used for moving figures on a sphere. The movement can take place in any direction within physical restrictions or defined parameters.

The US 5 413 010 A. describes an electric motor that has a spherical rotor.

The US 5 280 225 A describes a device that is designed as a drive system for a spherical body. Here, a sphere is rotated around several axes in the principle of a stepper motor. This method is used in the robotics area.

The US 3,178,600 A shows a structure with spherically arranged coils, wherein a rotation of a body about an axis is possible.

The US 3,260,475 A shows a special electric motor, the rotor of which is spherical and designed for space vehicles. The resulting torque can act in different directions, so driving in different directions is possible without special steering devices or gears.

From the US 2009/0 161 240 A1 a spherical camera is known, which is rotatably arranged in a hollow sphere. The spherical camera has permanent magnets which interact with electromagnets in the hollow sphere in order to pivot the spherical camera.

From the GB 2 458 905 A is known a camera that is gimbaled. The camera is pivoted by piezo drives.

From the US 5,946,127 A. a camera is known that can automatically track an object. For this purpose, the camera is spherical and arranged in a hollow sphere. The camera is driven by motors via spindle gears.

From the US 6 734 914 B1 Another bullet camera is known. This camera is adjustable by means of piezo drives.

From the US 7 612 953 B2 a generic camera is known which is adjusted by means of ion-conducting polymer films. By applying an electric field to these polymer films, they create a bend, which is then used to adjust the camera.

From the US 2012/0 038 815 A1 an adjustment device for a lens of a camera is known. This is adjusted by means of polymeric actuator elements, which create a bend in the material by applying an electrical field.

From the US 2003/0 117 044 A1 an actuator for a diaphragm pump is known. This actuator uses a spiral, which is coated with an electroactive polymer, to generate a movement of the membrane perpendicular to the membrane surface by applying an electric field.

There are rotating web cameras for laptops on the market. However, the rotation is purely mechanical by directly touching the webcam housing by hand.

A kind of webcam, which is also on the market, can move electrically, but is powered by electric motors and a small gear. The movement reaction speed is not particularly high.

Camera systems for smartphones are described, including those that can be rotated, but almost all of them are mechanical. Several smartphone manufacturers have designed smartphones that have a rotatable camera that is rotated mechanically by hand and can therefore take pictures from behind or from the front. Such cameras were also used in some laptops, such as older series from ASUS (model ASUS W5000). The camera here is installed on a rotatable frame and is rotated backwards or forwards by hand. However, this camera can only be rotated around an axis. In theory, you could also use a camera that can be rotated in several directions construct that would be mounted in a gimbal. However, an electrically rotatable camera in the conventional sense for notebooks is associated with several problems. The conventional drive (usually via stepper motors and gears) would be too large, too fragile, would destroy the aesthetics of the carrier device and the cabling would also have to be designed so that it does not tear off when the camera is rotated back and forth.

In the applications listed, the systems described there are quite complicated, not easy to implement on a very small scale and also relatively fragile.

There are similar principles that are theoretically transferable to a mobile phone, laptop, tablet PC, etc.

There are also methods to slightly pan an image sensor in the camera. The optical elements remain static. Such methods are used to stabilize the image, but the change in the field of view is only very small, so that no large effects are to be expected. This method also has physical limits. The further the image sensor moves, the more distorted the image becomes because the sensor moves in the field of view or focus point of the incident light rays. The optical elements do not follow the sensor movement. A method works similarly, whereby only one of the lenses (or a group of lenses) can pivot back and forth. Here, too, there are disadvantages in the form of image distortion with large pan amplitudes. Here, the incident light beam is more or less distorted, depending on how large the swivel amplitude of the lens is.

The well-known manufacturers (e.g. SONY, Panasonic, etc.) build electromagnetically movable lenses in smartphone cameras or in other high-quality devices. The lens can be moved back and forth along the optical axis. This is how the automatic autofocus setting works with high-quality cameras.

As described, there are enough electric drives for cameras (surveillance cameras, IP webcams, etc.), but mainly electric motors and also gears are used for the drive. The drive systems there are too coarse, too slow and it is almost impossible or very expensive to reduce them to the size of rice grains.

For a better understanding, each device that has a camera is called a carrier device. This can e.g. a video camera, clover camera, single-lens reflex camera, notebook, smartwatch (wristwatch with PC function and / or built-in mobile phone properties), tablet PC, webcam, drone, vehicle, plane, rocket, robot, surveillance camera, data glasses, mobile phone u. a. Smartphone, extreme sports camera, TV studio, movie camera, SteadyCam, etc.

The invention specified in the claims is based on the problem of creating a drive system for cameras of the type mentioned at the outset, which is able to rotate the camera smoothly and silently within a carrier device, with a movement effect almost like that of the human eye.

This problem is solved with the features listed in the claims.

Advantages of the invention are:
The camera rotates within the carrier device (for example, a smartphone does not have to be swiveled to capture a target object that is slightly to the left or right).
The camera makes very fluid, silent movements.
The invention hardly contributes to the weight.
It is well suited for small devices, preferably cell phones (smartphones).
It contains no wearing parts and is therefore very durable.
The direction of rotation of the camera can be changed quickly.
It can also be used optimally on moving, flying carrier devices such as vehicles, helicopters, rockets, drones, tablet PCs.
The invention is optimal for video surveillance devices, film, TV and studio purposes.
Tracking a moving object is possible.
The system is inexpensive to manufacture and the device is simple.

The invention relates to a drive system for the camera or rather for the image sensor and its optical accompanying elements, which is able to pursue a target to be photographed, to make a video recording of a moving object or a person, or an automatic rotation of the image sensor and to achieve its optical elements in order to take pictures or video recordings from behind and / or from the front with only one image sensor. The moveable camera system is extremely small, so that it can also be integrated in a small camera carrier device, in particular in a mobile phone (smartphone), tablet PC, webcam, wristwatch etc. It is able to move like a human eye or even faster and dynamically capture the field of view within existing parameters. The drive system is quite fast, silent and can be dynamic and dynamic within the camera carrier device move, rotate or rotate quickly so that pictures can be taken from different angles and also from the back and the front of the carrier.

In addition, the invention can be designed in such a way that it is also able to automatically recognize whether the image sensor and its optical elements should be directed forwards or backwards within the carrier device.

Embodiments of the invention are based on the 1 to 19 explained.

• 1 eine Variante, wobei die Kugelkamera einfach an elektroaktiven Kunststoffspiralfedern befestigt ist,
• 2 eine Variante mit Bi-Polymerantriebselementen,
• 3 eine Variante mit mehreren elektroaktiven Kunststoffspiralfedern,
• 4 eine Variante mit elektroaktiven Kunststoffspiralfedern, die in einer Kardanaufhängung eingebaut sind,
• 5 eine vereinfachte Teilkardanaufhängung mit nur zwei Achsen,
• 6 eine Variante mit elektroaktiven Kunststoffelementen in Form von Bändern oder Streifen,
• 7 ein spezielles Plastikfenster, das aus einem elektroaktiven Kunststoff gebaut ist,
• 8 eine 3D-Kamera,
• 9 eine leicht herausfahrbare Kamera,
• 10 eine Variante, die mit einem Schallquellenerfassungssystem ausgestattet ist.
• 11 einen konkaven Bildsensor,
• 12 eine Variante, wobei das Stoppen der Kugelkamera in einer bestimmten Position über einen elektromagnetisch herausfahrbaren Stift erfolgt,
• 13 eine Variante, die in einem Smartphone eingebaut ist, wobei die Kugelkamera zusätzlich in der optischen Achse rotierbar ist,
• 14 ein Smartphone mit der am Rand eingebauten Kamera,
• 15 ein Smartphone, bei dem die Kugelkamera an der Ecke eingebaut ist,
• 16 eine Variante, wobei eine Metallspirale mit einem elektroaktiven Polymer beschichtet ist.
• 17 eine Variante, wobei nicht nur der Bildsensor, sondern auch eine Art Beleuchtung, die das Blickfeld des Sensors beleuchtet, bewegbar eingebaut ist,
• 18 die Anordnung der Halbleiterdioden im Stromkreis,
• 19 eine Variante, bei der die Spirale aus zwei elektroaktiven Polymerschichten besteht.

Show it:

• 1 a variant in which the ball camera is simply attached to electroactive plastic spiral springs,
• 2 a variant with bi-polymer drive elements,
• 3 a variant with several electroactive plastic spiral springs,
• 4 a variant with electroactive plastic spiral springs, which are installed in a gimbal,
• 5 a simplified partial gimbal suspension with only two axes,
• 6 a variant with electroactive plastic elements in the form of strips or strips,
• 7 a special plastic window built from an electroactive plastic,
• 8th a 3D camera,
• 9 an easily removable camera,
• 10 a variant that is equipped with a sound source detection system.
• 11 a concave image sensor,
• 12 a variant, the ball camera being stopped in a certain position by means of an electromagnetically extendable pin,
• 13 a variant that is built into a smartphone, the ball camera can also be rotated in the optical axis,
• 14 a smartphone with the camera built in at the edge,
• 15 a smartphone with the bullet camera installed on the corner,
• 16 a variant, wherein a metal spiral is coated with an electroactive polymer.
• 17 a variant, in which not only the image sensor, but also a type of lighting that illuminates the field of view of the sensor is movably installed,
• 18 the arrangement of the semiconductor diodes in the circuit,
• 19 a variant in which the spiral consists of two electroactive polymer layers.

Electroactive polymers (abbreviated to “EAP”) are polymers that can change their shape when an electrical voltage is applied. A general distinction is made between ionic EAPS and electronic EAPS. In ionic EAPS, the mechanism of action is based on mass transport (diffusion) of ions, whereas the mode of action of electronic EAPS is based on electronic charge transport. Advantages of EAPS compared to other actuator materials, such as B. piezoelectric ceramics, are the extremely high strains that can be achieved as well as the low density of the polymers and their free formability.

The first scientific work on EAPS was published in 1880 by Wilhelm Conrad Röntgen. He did an experiment with a rubber band that he hung on one end and stretched the free end with weights. After an electrical charge, he noticed an increase in length of several percent. As soon as the rubber was electrically discharged, the expansion decreased.

The same principle is used here for the movement of the camera. Here, too, electroactive polymers (plastics) in the form of strips or spiral springs are installed and coupled to the camera, which are rotated in a controlled manner within the carrier device.

The camera sensor 1 and its accompanying optical elements 2 are preferably in a small spherical housing 3 , hereinafter referred to as a spherical camera, mounted in a hollow sphere housing 4 , hereinafter called the hollow sphere, which is only slightly larger than the spherical camera. The spherical camera can easily be placed loosely and freely rotated in the hollow sphere, using one or more electroactive plastic elements 5 connected to the spherical camera at one end and to the hollow sphere at the other end ( 1 ). The camera can also be attached to a simple gimbal 8th be attached, in which case the bullet camera 3 no longer (or only rarely) touches the wall of the hollow sphere. The hollow sphere 4 is statically attached to some variants, i.e. immovable, only the camera ball moves in it.

Especially a camera on a tablet PC, I-PADs, I-Phones, smartphones or other Mobile phones can be installed in such a way that they can be rotated electrically backwards or forwards in the housing and are suitable for both rear and front shots. Also in a mobile phone, the camera is preferably built in the form of a sphere and placed in a hollow sphere, similar to how the human eye is in its cavity, the hollow sphere being transparent or having at least in part a window through which the spherical camera transmits light from the environment. The bullet camera is complete with the image sensor 1 , Electronic components and accompanying optical elements 2 (e.g. lenses, mini prisms, etc.). The bullet camera 3 is not rotated by gears or electric motors as usual, not manually by touch, but by one or more electroactive plastic spiral springs 5 or electroactive plastic strips 33 electrically controlled in a targeted direction rotated or swiveled.

The swivel or the rotation can be in one or more axes 7 respectively. Multi-axis rotations can be done by a gimbal 8th can be realized if the bullet camera 3 should not touch the wall of the hollow sphere ( 2 ).

The simplest variant provides that the spherical camera, especially in the case of small devices, is in the hollow sphere 4 is simply arranged to move freely, this being due to the electroactive plastic spiral spring 5 held and also rotated. The bullet camera 3 does not necessarily have to be stored. It can touch the walls of the hollow sphere, but its weight is very low, so that there is hardly any friction when it is rotated back and forth by the electroactive plastic spiral springs. The material from which the spherical camera housing and the hollow sphere are made should be scratch-resistant (at least the surface coatings that will rub against each other) and possibly also be self-lubricating (at least in some areas). The current signal is transferred to the image sensor through a flexible cable 9 , The camera can also have other shapes (such as an egg, oval) or can have small edges, but the shape of a sphere is best suited for this. The spherical camera is coupled with electroactive plastic spiral springs (polymers), which are also connected to the hollow sphere at the other end. It is swiveled or rotated in any direction, simply by expanding the tensioned spiral spring, whereby a torque is generated in the center. As soon as an electroactive plastic spiral spring is under tension, it will expand and generate a torque at the center of the spiral. The electroactive plastic coil spring is very thin because it has to be activated quickly and with very little current and should also shorten just as quickly when the voltage is switched off. After all, only small torques are required to move a very small camera in a mobile phone. The ball camera is rotated quickly and silently in any direction by the electroactive plastic spirals, depending on which of the spirals is active. Depending on which of the electroactive plastic coil springs is active or is under tension, the ball camera is pivoted in the direction that corresponds to the torque of the active electroactive plastic coil spring. Because the electroactive plastic spiral spring or strip can only turn the spherical camera in one direction under tension and turns back when the voltage is switched off, there is a need for each axis 7 at least two of them working against each other, electroactive plastic coil springs 5 or strips 33 necessary to actively pivot the ball camera 3 in the desired direction. If one of them is activated, the spherical camera is turned in this direction, despite the slight resistance of the mechanical tension of the counter-spiral. If there is no voltage on an electroactive plastic coil spring, the ball camera turns back to the starting position. If the other spiral spring-shaped electroactive plastic element is activated, the spherical camera then rotates in the other direction. One control 6 ensures that the tension of the electroactive plastic spiral spring or strip occurs exactly and holds the specific position of the spherical camera. The drive with electroactive plastic spiral springs or strips is not suitable for extremely fast swiveling, but it can also be controlled quite precisely, works maintenance-free and reliably. The thinner and smaller the electroactive plastic elements, the faster the reaction and the lower the power consumption. The position of the spherical camera is maintained by constant, precisely controlled voltage maintenance on the corresponding electroactive plastic elements (polymer) or by maintaining the electrical voltage. If the voltage on an element increases, the torque in the electroactive plastic element also increases. Due to the fact that the electroactive plastic elements are thin and have a low mass, an inertia is hardly noticeable. This method is relatively simple and also works very reliably and completely maintenance-free. Above all, no further installation measures are necessary. Only the electroactive plastic elements (e.g. electroactive plastic spiral springs) have to be installed on the rotary axes and with power lines 10 at the control 6 and electronic voltage generator 39 be coupled. As soon as precisely controlled voltage values are applied to the electroactive plastic elements, they become more or less active and generate an expansion. Because this is spiral are formed, a torque is generated which causes the ball camera to rotate. The ball camera is very small in small devices such as cell phones (smartphones), notebooks or tablet PCs, weighs only a few grams and can therefore be rotated with very little force.

The electroactive plastic elements hardly put a load on the battery of the camera carrier device because its power consumption is very low. The electroactive polymer spiral springs can be operated via the electronic voltage generator 39 (a kind of voltage converter). The task of the evaluation unit or control 6 , which supplies the coil spring with power, it is, depending on the necessary rotation of the camera, to apply a certain voltage to the corresponding electroactive plastic coil springs so that they become active with the desired intensity. The expansion takes place at lightning speed, also because the spiral spring is quite small and has only a small mass. Pulling off takes place just as quickly when the voltage is switched off. This enables the ball camera to move relatively quickly.

The spherical camera is coupled to the hollow sphere via several electroactive plastic spiral springs ( 3 ), at the center of which are the axes of rotation for the spherical camera. Several such electroactive plastic coil springs 5 , which are arranged in two-dimensional axes or even three-dimensionally, thereby enable two-dimensional or three-dimensional rotary movements of the spherical camera housing. A movement of the spherical camera in two axes would be completely sufficient for common purposes. The less mass the coil spring has, the faster its reaction or movement. In order to achieve a pivoting in any direction about two axes, at least four such electroactive plastic elements are necessary (two for each axis of rotation, which are arranged mutually working).

In the 6 a simple variant is shown, the ball camera hanging on the electroactive plastic coil spring and being activated in certain directions of rotation by its activation. Through interaction of the software, which also controls the control unit for the drive system, the spherical camera will perform smooth movements while pursuing a goal.

Supported by the software (mainly via that of the carrier device), the target to be photographed can be detected and tracked if it does not move too quickly, while always remaining almost in the center of the image. So-called face tracking can be implemented because the camera can track the face of a moving person by rotating it and always places the face in the center of the recorded images. The attempt of the object to be photographed to move away from the central area of the image sensor detection angle is compensated for by pivoting the spherical camera until the end of the entire field of view is reached. It is similar to how a person follows a moving object with his eyes without turning his head. The spherical camera can also be rotated completely backwards, an additional rear camera would be omitted, which is particularly interesting for mobile phones.

The camera of the invention has clear advantages over the prior art. This camera is rotated within the carrier device via electroactive plastic spiral springs (polymer) or electroactive plastic strips, the rotation taking place relatively quickly and silently. It can take pictures from behind and from the front and it is not only rotated back and forth, target tracking can also be implemented, which can also be automatic. Because not the whole camera mount housing 11 turns, but only the part or the compact extra housing 3 in which the image sensor 1 and its look 2 a relatively quick swivel is possible. The bullet camera 3 would look back and forth here like a human eye. Use in a surveillance camera, drone camera, robot camera, vehicle camera, etc. is also ideal.

In the 2 spiral spring elements are provided as drive elements, which consist of two layers. One of them is an electroactive polymer layer 40 which is stretchable under electrical tension. The spiral spring elements 41 here are not built entirely from electroactive polymer, but are designed in the form of bi-polymer coatings, with one coating being a normal plastic 42 which is electrically neutral and cannot be activated and the other is an electroactive polymer. The spiral is built similar to the spiral spring of wind-up mechanical watches. It has two wider areas, one inside 46 and an outside surface 47 , One of the surfaces (regardless of whether the outer surface or the inner surface) is made of electroactive plastic. This way, for the rotation of the bullet camera 3 the differential expansions generated by the electroactive plastic coating in the spiral by tension, which are converted into a torque. As already known, the rotation occurs due to the different expansion coefficients of the two interconnected polymer or plastic layers that make up the spiral spring, one of which is electroactive. The principle of operation is similar to that of bimetallic spiral springs, which rotate when there are temperature differences because the metal layers have different expansion coefficients. Such Bimetal coil springs have been used in simple bimetal thermometers. Of course, there is no need for a 360 ° rotation here, which stops continuously like with an electric motor. Rather, these swivel movements only have to turn the camera back and forth.

The drive element or the spiral can instead of two plastic layers made of a metal or an alloy 43 be built on an area with an electroactive plastic coating 40 having. This coating causes the expansion to deform the spiral or to generate a torque in the middle of the spiral that can be used as a driving force ( 16 ).

The same principle is used here for rotating the camera of a smartphone or other camera carrier device. Here you can use several bi-polymer spirals 41 with electroactive plastic coatings or electroactive plastic spirals 5 that can rotate the spherical camera in any direction. In addition, two electroactive plastic spiral springs can be used for each axis of rotation, which generate opposing torques. The electroactive plastic spiral springs are specifically energized and thereby actively expanded. A rotation of the spherical camera in two axes would be sufficient and would only require two or four electroactive plastic spiral springs. A simplified partial gimbal suspension 13 with only two axes can be very suitable for this. This suspension 13 consists, as in 5 shown, from only a quarter circle long arm 14 , with a swivel at both ends 15 Is provided. The spherical camera is attached to one swivel and the hollow sphere is coupled to the other. An electroactive plastic coil spring is installed on each of the swivel joints, which can cause the body attached to the joint to rotate when current flows. The tension is guaranteed separately for each spiral spring by separate flexible cables.

For swiveling in the vertical axis 7A becomes the electroactive plastic coil spring 5A activated. About a swivel in the horizontal axis 7B the electroactive plastic spiral spring 5B put under tension and thereby expanded. The installation of four electroactive plastic spiral springs (installed in pairs and in the opposite direction of rotation) enables a more precise rotation of the spherical camera.

Because the bullet camera 3 within the hollow sphere 4 is rotatable, it can be used both as a rear camera and a front camera. Of course, the ball camera does not turn in an uncontrolled manner, but is positioned very precisely on the desired field of view via the control of the electroactive plastic spirals. Stopping in the desired position can be done by maintaining the voltage of the active electroactive plastic coil spring and possibly by briefly activating the opposite electroactive plastic coil spring. The hollow sphere 4 can be built completely transparent or it can be placed in certain places with large light windows 17 be equipped, through which the light from the image motifs or the environment comes into the camera ball and also reaches its sensor. Small additional optical elements (lenses) can successfully correct a slight image distortion caused by the spherical windows. The camera can also be moved more or less out of the carrier device in order to enlarge the viewing angle. In this case, a further electroactive plastic spiral or an electroactive plastic strip would be necessary which more or less moves the hollow sphere or a hollow cylinder in which the spherical camera is attached out of the carrier device.

The conductor connections between the electroactive plastic spiral spring or strip and the movable ball camera 3 and a signal processing unit 34 , which is outside the encapsulated sphere, are somewhat longer, flexible lines 9 that no longer hinder the movements of the bullet camera. These conductors or micro cables have to withstand a lot of swiveling and always allow perfect signal transmission. Intertwined micro cables, which are known from the loudspeaker membranes, can withstand a lot of vibrations. Although the spherical camera not only vibrates here, but is also rotated back and forth, such cables can last a few years under daily stress. Theoretically, the electroactive plastic coil spring can also be used for the current signal transport.

As described, the spherical camera can easily be installed loosely in the hollow sphere without any bearings. A gimbal would be optimal and a little more expensive. All it takes is a greatly simplified gimbal suspension 13 with just a small arm 14 , like in the 5 is shown to install. One control 6 can quickly generate a counterforce when the ball camera reaches a certain rotational position via the electroactive plastic coil spring until the expansion of the active coil spring decreases a bit, which counteracts further rotation of the ball camera. Small bristles can also be used to quickly stop the rotation 49 or place small sponge bodies between the hollow sphere and the spherical camera, these being free at one end and coupled to either the wall of the hollow sphere or the sphere at the other end.

When using a full-card hitch 8th and variants in which the ball camera is simply inserted loosely into the hollow sphere, no vibrations are to be expected as soon as the desired position is reached and the active electroactive plastic spiral springs are supplied with voltage evenly. Because the camera is also around the optical axis 36 can rotate, photography or the creation of perfect images is possible even when the carrier device is held at an angle. The picture is always perfectly straight, no matter how inclined you hold the camera. Via the control unit and, of course, software support of the carrier device, the camera image sensor for video recordings can be rotated automatically so that widescreen recordings are made. In the case of single image recording, the photo recordings can be aligned vertically if desired.

In the 6 is a variant with electroactive plastic elements in the form of strips or strips 33 shown, wherein a pivoting of the ball camera can be achieved. Electroactive plastic elements are installed here, which can expand and deform as a result of tension, causing the ball camera to pivot. The electroactive plastic elements connect the spherical camera to the hollow sphere, whereby the connection to the spherical camera is tangential, similar to the human eye and its muscles.

In a variant that in the 7 is shown, the material of the optical window 17 the camera carrier device, which protects the field of view of the image sensor, made of an electroactive, transparent plastic 18 manufactured, which is able to expand electrically controlled, the edge of a non-stretchable ring 44 consists. Because the expansion is limited by the ring, a dome becomes temporary 19 formed outwards, into which the spherical camera can penetrate in order to significantly expand the viewing angle. This is advantageous if the carrier device (eg the mobile phone) is on the table and the entire room should be monitored remotely from this position. By rotating the camera and creating the dome 19 , an almost semi-spherical field of view can be monitored.

With a sound control, which is coupled to the drive system, the camera can then be automatically aligned where the sound or voice comes from. In this case, the camera carrier device has a stereo microphone 28 or directional microphone, which is also the case with mobile phones. The drive system can control an electronic coupling of the two systems, that is to say audio and optical detection systems. As a result, the movement of the camera can be automated, whereby it is directed exactly in the direction of the voice or sound source for image recording or video recording.

The rotatable ball camera can with a return spring 20 or a permanent magnet 21 that has a ferromagnetic region or ferromagnetic body 22 (preferably iron or nickel) in a rest position. The return spring or the permanent position permanent magnet ensure that when the active rotation of the ball camera is switched off, a certain restoring force rotates the ball camera to a certain position. Another permanent magnet built into the wall of the hollow sphere attracts the ferromagnetic body or other permanent magnet built into the spherical camera ( 10 ).

The electrical and signal transmission from the sensor to the evaluation unit takes place through a thin and extremely flexible cable 9 ideally shaped like a feather. The fine signal lines are intertwined, similar to the lines of a magnetic coil in a loudspeaker membrane. This method has proven itself in order to protect the lines from damage. It is known that the loudspeaker diaphragm undergoes a very high number of vibrations (several hundred billion) throughout its "life", with the power lines between the housing and the loudspeaker coil undergoing countless movements and vibrations, even after years of operation. The same technique can also be used here. This ensures long-lasting, flawless signal and power transmission between the image sensor and the carrier device (e.g. a smartphone) despite the movement of the image sensor. If a longer line is used which is finely interwoven and which is also more or less helically shaped like a spring, an almost complete rotation of the image sensor and its optical elements can be achieved. The inside diameter of the hollow sphere is only slightly larger than the sphere in which the image sensor and its accompanying elements are installed. By generating torques via the electroactive plastic spiral spring, you can achieve any rotation of the ball camera.

The lighting elements 23 No matter whether they emit radiation in the spectrum of visible light or in the infrared range, the camera can be moved. This enables optimal lighting that tracks the movement of the field of view of the spherical camera. A flash light, preferably a strong light-emitting diode, which is built into the camera ball, can also be used for this ( 17 ).

The 4 shows a variant with electroactive plastic spiral springs, which are installed in a gimbal. The coil springs are microelectroactive plastic elements that expand quickly due to tension and thus cause the camera housing to move. The bullet camera can be mounted in a full gimbal 8th with three-axis rotation or partial gimbal mounting 13 attach with only two axes of rotation, the axes of rotation being coupled with electroactive plastic springs ( 5 ).

Depending on which of them is active, a swivel of the spherical camera is generated. Because the electroactive plastic elements can only rotate the ball camera in one direction when it is live and turn it back when it is switched off, at least two electroactive plastic elements working against each other are necessary for each axis in order to achieve an active pivoting of the ball camera in the desired direction. If one of them is activated, the ball camera is also turned in the direction against the slight resistance of the counter-working spiral. If you switch off the electroactive plastic coil spring, the ball camera turns back to the starting position. If the other electroactive plastic element is activated, the spherical camera then rotates in the other direction. A control ensures that the activation of the electroactive plastic elements takes place exactly and also holds a certain position of the spherical camera.

The variant with electroactive plastic elements is not suitable for extremely fast swiveling, but can be controlled quite precisely and works maintenance-free and reliably. The thinner and smaller the electroactive plastic coil springs or strips, the faster the reaction and the lower the power consumption. Maintaining a position of the spherical camera is achieved by constant voltage maintenance or controlled current flow through the specific electroactive plastic element. If the electrical voltage increases, the expansion effect of the electroactive plastic spiral spring is increased at the same time, thereby generating a higher torque. This method is relatively simple and also works reliably. No further installation measures are necessary here. It is only necessary to install the electroactive plastic elements (e.g. electroactive plastic spiral springs) in the rotary axes and to couple them with power lines from the control. As soon as voltage is applied to the electroactive plastic elements, they are more or less expanded and a torque is generated in the process. Because these are spiral-shaped, a torque is generated in the middle that causes the spherical camera to rotate, similar to the simple bimetallic coil spring thermometers.

For 3D image acquisition two such cameras and systems are necessary, which are best set up at a distance from each other ( 8th ).

In all variants, the camera is installed like a human eye in a hollow sphere and is also equipped with a tracking mechanism, which is controlled by software and then automatically tracks the person or the person's face.

The camera can be designed so that it can be easily lifted out of the mobile phone or tablet PC, either electromagnetically or electrically, so that it protrudes a bit if the device is left somewhere ( 9 ). The cover lens or dome or a transparent hollow cylinder 24 in which the camera 3 can be easily removed in this case. The ideal would be a transparent hollow cylinder with dome-shaped ends that also have viewing windows 17 are for the image sensor. The hollow cylinder can be made with a ferromagnetic ring 25 be equipped in the middle, by an externally statically attached electromagnetic coil 26 is tightened, the hollow cylinder being raised, depending on how the mobile phone is located, or the camera is moving forwards or backwards. Instead of the ferromagnetic ring, a permanent magnet or permanent magnet ring can also be used 27 be installed, which then moves according to the polarity of the electromagnetic coil. The variant with the permanent magnet is easier to manufacture because it only requires a small magnet at the bottom of the cylinder and an electromagnetic coil 26 below are necessary. The cylinder becomes due to magnetic field interaction 24 pushed up or tightened depending on how the coil is poled. The dome-shaped ends are of course transparent and each form a window through which the camera sensor receives light. Due to the dome there is hardly any or a slight distortion of the image, which is calculable and can be easily corrected by software. The use of a correction lens in the optical system of the image sensor can also eliminate the distortion.

The 10 shows a variant that is equipped with a sound source detection system. Here is a stereo microphone 28 used to be a sound source 29 to localize. As soon as this has been done, the drive system is controlled by a controller so that the camera is directed directly to where the sound source is located. This means that when a video is recorded, the person being recorded can be automatically followed by the camera when it speaks.

The tracking of moving objects can be supported by the software of the carrier device. On the control screen of the carrier device, an object can be marked with a finger touch, which then automatically follows the camera no matter how it moves or how the camera carrier device is held. The main task does it Drive system that enables the rotation of the image sensor.

When taking pictures or videos with conventional mobile phones (smartphones), you notice that the objects on the edge are often slightly distorted. This is because the image sensor is flat and the optics correction elements that could solve the problem hardly find space in a smartphone. The image sensor should not necessarily be flat, but can be slightly concave to better mimic the retina of the human eye. In this case, distortions of the image motif would hardly be perceptible ( 11 ).

For the manufacturing process of such concave image sensors 30 a dome-shaped micromatte made of plastic with a memory effect can be used very well. As soon as the doping is complete and the physical strength of the sensor is reached, the dome-shaped plastic part will bend flat again and thus detach from the sensor. In one variant, the image sensor is always shaped flexibly in the camera. Through a special, electrically formable polymer layer 48 and a controller, the image sensor, which is coupled to this layer on the back, can always be deformed and thus be adapted to the lighting conditions. An auto focus function would also be possible. Thus, the optical elements would not have to be moved too much, but rather the image sensor should change its degree of bending or be designed flexibly ( 11 ).

In the 12 a variant is shown, the stopping of the bullet camera in a certain position using an electromagnetically extendable pin 31 he follows. As soon as the desired position of the spherical camera is reached, it should then be stopped immediately and held in this position. The stopping can be done by a small pin that by an electromagnetic coil 31 is moved out of the hollow sphere wall in the direction of the spherical camera and then touches it stopping.

The spherical camera does not necessarily have to rotate completely, for many applications it is sufficient to swivel it slightly in two axes (two-dimensional movement - up, down, right, left and thus any combination between these four directions), which can be achieved in many ways can. They track the object like an eye and you get sharp photos, even if the objects move. If you build two such spherical cameras on a carrier device (e.g. smartphone, laptop, tablet PC, webcam, etc.) at a small distance from each other, you can achieve stereo images or 3D recordings.

The 13 shows a variant that is installed in a smartphone, the ball camera can also be rotated in the optical axis. This variant is interesting because - no matter how straight or inclined you hold the smartphone when taking pictures - good straight pictures are always created when this function is activated. In video mode, the spherical camera is rotated so that the pictures are taken perfectly horizontally, so that you no longer make mistakes with holding the smartphone differently during video or picture recordings. A simple shift of the center of gravity downwards or a small electrically movable or tiltable weight can be used for the rotation 35 serve, which is built into the spherical camera, which always aligns the spherical camera so that the images are captured perfectly in a vertical position. As soon as the video mode is switched on, the weight piece 35 electrically around the optical axis 36 rotated by 90 ° and video recordings can be made, the video recordings always taking place horizontally, even if the smartphone is rotated in any direction. The weight piece can be a permanent magnet, which is by one or more electromagnets 50 , is offset by 90 ° around the optical axis. The electromagnet 50 is arranged so that it builds up one pole in the area of the permanent magnet and the other outside, which no longer has any influence on the permanent magnet ( 13 a) ,

The variant in the 13b is a bit better designed. Here the electromagnet is placed closer to the permanent magnet and both ends are slightly bent to limit the movement of the permanent magnet exactly to 90 °. Both ends 53 of the electromagnet 50 are polarized and depending on how the current flows into the coil 54 a corresponding magnetic field orientation is generated. The core 52 this electromagnet is made of iron. As soon as the permanent magnet is attracted in one direction, it sticks to one end 53 of the iron core and remains there even when the electromagnet is switched off. This means that only a small current pulse is necessary to achieve the pivoting or shifting of weight by 90 ° into the camera ball. If the weight is to be shifted to the other side, the electromagnet will 50 reversed by a changed current flow, so that it generates repulsive forces at the point of arrest, the permanent magnet releasing and moving in the other direction until it then sticks again with its opposite pole. A counterweight 51 is additionally and statically attached in the ball camera opposite, so that there is no weight shift due to the electromagnet, which is also attached statically. The electromagnet is controlled by a controller 55 controlled, which is either integrated into the rotatable housing or installed somewhere outside in the mobile phone. The shift in weight thus only causes the permanent magnet with its swiveling movements. Where it stops, the center of gravity is shifted and thus the spherical camera, which is freely rotatable, is rotated in the corresponding direction by the force of gravity.

The 14 and 15 show a smartphone 37 where the bullet camera 3 on the edge or better still at one of its corners 38 is installed, whereby a rotation from front to back enables an image of over 180 °. The detection angle can be over 300 ° if you consider that the camera can also be directed obliquely downwards, both in front and behind (if you hold the smartphone vertically, for example).

16 shows a variant, wherein a metal spiral is coated with an electroactive polymer. The metal spiral 43 is applied by applying a voltage to the electroactive polymer coating 40 stretched on one side and thus deformed, creating a torque in the middle. Of course, the metal of the spiral from the electroactive plastic layer is electrical through an insulator 45 isolated, because otherwise only a short circuit would occur. A simple lacquer layer can be used as the insulator layer.

The 17 shows the installation of lighting elements, preferably LEDs, which are directly coupled to the camera and rotate with the camera. This optimizes the illumination of the image motif, because every rotation of the camera also aligns the illumination in the same direction, so that the light from the image motif is always optimally reflected in the image sensor.

Like in the 18 shown, the electroactive polymer elements 40 with one semiconductor diode each 16 be equipped in such a way that one element is under voltage when there is a current flow and the other when the current flow is reversed. This has the advantage that two electroactive polymer elements are coupled with only two instead of four lines. The current flow reversal alone determines which of the polymer elements is activated.

In the 19 a variant is shown in which the spiral consists of two electroactive polymer layers 40 which is electrical through an insulator layer 45 are separated. The two broad surfaces of the spiral, both the outer surface 47 as well as the inner surface 46 here consist of electroactive polymers and are energized separately from the control. If the outer surface is put under tension, the spiral contracts and thus rotates towards its center. Depending on how long the spiral is built, the rotary movement takes place accordingly. As soon as the inner surface is put under tension, this surface expands, causing the spiral to spread. In this case too, there is a rotary movement in the center of the spiral, but in the opposite direction than before. Here, too, two electrical lines are sufficient to be able to control both surfaces of the spiral separately. However, it is again necessary to install at least two semiconductor diodes, which are coupled in opposite directions to each of the polymer layers and thereby separate the voltage build-up for each layer, as in FIG 18b is shown.

Claims (18)

Drive system for a freely rotatable camera, which has an image sensor (1) and optics accompanying elements (2) and is provided within a camera carrier device, the drive system being coupled to the preferably spherical camera, and the drive system having at least one drive element which has a band in the form is a spiral (5), and the band is coupled at one end to the camera and at the other end to the camera carrier device, and the band consists of at least two layers, one layer forming the outer surface and the other the inner surface of the band, at least one of which is an electroactive polymer coating (40) that expands under tension and thereby generates a torque, and the electroactive polymer coating (40) is coupled to power lines in order to supply them with power, and the at least one drive element is an evaluation unit or Control has the electroactive polymer coating (40) puts tension and thereby actively expands it, characterized in that the band consists of metal or an alloy, the electroactive polymer coating (40) being applied on one side, and the metal or alloy in the spiral (5) is electrically isolated from the electroactive polymer coating (40). Drive system according to Claim 1 , characterized in that the spiral (5) consists of two separately electrically controllable electroactive polymer coatings (40) and an intermediate insulation layer which electrically separates the polymer coatings (40) from one another. Drive system according to Claim 2 , characterized in that the insulation consists of a layer of lacquer. Drive system according to one of the preceding claims, characterized in that the image sensor (1) and its optics accompanying elements (2) are installed in a separate housing (3), which is preferably constructed spherically and is rotatable within the camera carrier device, which in a hollow sphere with light windows (17) is placed, which is part of the housing (3) of the camera carrier device. Drive system according to one of the preceding claims, characterized in that a plurality of electroactive polymer spiral springs (5) are installed which are arranged such that they can rotate the camera in different axes (7). Drive system according to one of the preceding claims, characterized in that at least two electroactive plastic elements, preferably electroactive polymer spiral springs (5), which work separately and are supplied with voltage, are installed per axis of rotation (7). Drive system according to one of the preceding claims, characterized in that one or more lighting elements (23) in the visible light spectrum or in the infrared range are integrated with the rotatable camera and are movable with it. Drive system according to one of the preceding claims, characterized in that the rotating image sensor (1) and its optics accompanying elements (2) are stopped in a certain position via an electromagnetically extendable pin (31) built into the hollow sphere, which touches the camera and continues to rotate prevents. Drive system according to one of the preceding claims, characterized in that the system is duplicated and is designed for a 3D image acquisition. Drive system according to one of the preceding claims, characterized in that the camera can be easily moved out of the camera carrier device electromagnetically or by further electroactive plastic elements. Drive system according to one of the preceding claims, characterized in that the evaluation unit or the control is coupled to a sound source detection system and the corresponding control of the electroactive polymers rotates the camera in the direction of the sound source. Drive system according to one of the preceding claims, characterized in that the camera is mounted in a gimbal, on the axes (7) of which at least one electroactive polymer spiral spring (5) is installed. Drive system according to Claim 4 , characterized in that a spring which is coupled to the rotatable housing (3) of the image sensor (1) with the optical elements (2) and the hollow sphere is installed as a return spring (20). Drive system according to one of the preceding claims, characterized in that the camera is installed on the edge or on a corner of the camera carrier device, an all-round viewing angle range being available from the perspective of the image sensor (1). Drive system according to one of the preceding claims, characterized in that the camera can only be rotated on one axis with two main image detection positions of 0 ° and 180 °, with 0 ° image or video recordings from the front and 180 ° image or video recordings from the Back of the camera carrier device mean. Drive system according to Claim 15 , characterized in that the camera can take further intermediate image acquisition positions from 0 ° to 180 °. Drive system according to one of the preceding claims, characterized in that the image sensor (1) of the camera is concave. Drive system according to one of the preceding claims, characterized in that the electroactive polymer coating (40) is coupled to semiconductor diodes (16) which divert a current depending on the direction of current flow to a specific polymer coating (40).

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