WO2009068524A1

WO2009068524A1 - Device and method for protecting a graphic representation on a projection surface

Info

Publication number: WO2009068524A1
Application number: PCT/EP2008/066145
Authority: WO
Inventors: Julius Von Bismarck
Original assignee: Julius Von Bismarck
Priority date: 2007-11-27
Filing date: 2008-11-25
Publication date: 2009-06-04
Also published as: DE102007057272A1; DE102007057272B4

Abstract

The invention relates to a device for projecting a graphic representation on a projection surface, having a light source (1, 1005, 1050), which is coupled to a projection unit (3, 4, 9), for emitting a first light. According to the invention, the device has a control unit (13, 1003) having a light-sensitive sensor, which is provided and set up for the purpose of generating a control signal for activating the light source (1, 1005, 1050) as a function of a second light acting on the sensor, wherein said light source (1, 1005, 1050) passes back into a deactivated state after the emission of the first light performed by the activation. Furthermore, the invention relates to the use of such a projection device and a method for projecting a graphic representation on a projection surface (102, 103).

Description

Apparatus and method for projecting a graphical representation on a

projection

description

The present invention relates to a device for the projection of a graphical representation on a projection surface according to the preamble of claim 1, a method for the projection of a graphical representation on a projection surface according to the preamble of claim 16 and the use of a device for the projection of a graphic representation onto a projection surface according to the preamble of claim 27.

Devices for projecting a graphical representation on a projection surface have long been known. A common feature of these projection devices is that they project one or several graphical representations, in particular images, onto a projection surface over such a long period of time that a human eye can perceive the projected image. In a rapid sequence of projected images, the projected images are presented to the human observer as a movie. Slide projectors, motion picture projectors, or projectors are examples of projection devices known in the art.

The present invention has for its object to provide a projection apparatus and a corresponding method in which a graphical representation which is only very short or substantially invisible to the human eye, but can be visualized by an aid.

This object is achieved by a device for the projection of a graphic representation having the features of claim 1.

Such a device for projecting a graphic representation onto a projection surface initially has a light source and a projection unit coupled thereto. By means of such a device, a single graphical representation as well as various graphical representations can be sequentially or simultaneously projected. As a projection surface is any arbitrary planar-like shape, which does not necessarily have to be a surface in the mathematical sense. For example, a house wall, a crown of a tree (with and without leaves), a canvas, a sign, a window, a dormant or moving vehicle, a person, an animal, and the like are suitable projection surfaces.

According to the invention, the device also has a control unit with a light-sensitive sensor, wherein the control unit is provided and configured to generate a control signal for activating the light source as a function of a second light acting on the sensor. The light source emits the activation of the first light and then goes back to a deactivated state after the first light has been emitted. In this deactivated state, the light source is susceptible to reactivation by a control signal of the control device.

The photosensitive sensor can have a lens which reduces the angle of the incident light. This makes it possible to selectively "pick" or select particular sources of second light and disregard other sources of second light for sensor activation, thereby increasing the sensitivity of the sensor, which is particularly useful in bright ambient light.

In the context of the present invention, the first light is always understood as meaning light which is emitted by the light source. This light is not suitable for activating the light-sensitive sensor of the control unit. For this purpose, the second light is necessary, that is, such light, which is just not from the Light source of the device is emitted. For example, a single light signal or a plurality of light signals can serve as first and / or second light.

Basically, in the context of the present invention, light is understood to mean electromagnetic radiation of very different wavelengths, which is both visible and non-visible to the human eye

Radiation includes. For example, UV radiation and infrared radiation also belong to the present concept of light as well as light of the wavelength of about 400 nm to about 800 nm, which is commonly understood to be visible to the human eye. Although no limitation of the present invention to a particular type of light is technically necessary, it is particularly suitable for the use of visible light in the case of first light and / or second light.

In one embodiment, the photosensitive sensor detects the absolute amount of light or light intensity acting on it. In this case, a specific threshold can be preset. If this threshold is exceeded, it will generate a

Control signal for activating the light source. The threshold is adjustable so that ordinary ambient light does not yet result in generation of the control signal, whereas a sudden or continuous increase in the amount of light will result in the generation of the control signal when the threshold is exceeded.

Such a light quantity increase can be done, for example, by a flashlight or a newly activated headlights.

It is also possible that the photosensitive sensor, in addition to the absolute amount of light or, alternatively, relative changes in the acting on it

Detects amount of light and, if these changes exceeds a previously adjustable level, also causes the generation of the control signal in the control unit. In principle, it can be assumed that the second light, which is detected by the photosensitive sensor, is brighter than the ambient light acting on the photosensitive sensor. The determination of a relative amount of light can also be such that not the light intensity, but the duration of a specific light pulse, that is, the duration of the action of a certain

Amount of light on the photosensitive sensor, is determined. In this case, for example, the slope of a curve, which represents the entire light quantity or intensity acting on the photosensitive sensor over time, can serve as a suitable measure. As soon as a flash is triggered, the amount of light acting on the photosensitive sensor abruptly increases, that is, the corresponding curve has a large slope. For example, if the slope of this curve exceeds a certain level, a control signal may be generated in the control unit.

The projection unit is in particular designed such that it has at least one optical beam path through which a first light, that is to say such light emitted by the light source, can radiate.

In order to allow a particularly simple connection between the control unit and the projection unit, the control unit in a variant has a connecting element formed on the control unit, which serves for connection to the projection unit. In addition, in the connecting element

Be arranged contacts that allow transmission of control signals or other electrical pulses between the control unit and the projection unit. Also, a further (additional) contacting of the light source by the arranged in the connecting element contacts is possible.

The connecting element may, for example, be designed as an accessory shoe plug which is inserted into an associated accessory shoe of the projection unit and thus fulfills its functions. Moreover, it is possible to produce further contacts between the control unit and the projection unit or the light source in addition to contacts present in the connection element. Such contacts can for example be realized via ordinary electrical conductors (cables), which need not be formed directly on the control unit, but can also be connected to it.

It is also conceivable that a signal transmission takes place between the photosensitive sensor or the control unit on the one side and the projection unit on the other side by means of a wireless transmission. In this way, it is possible that the photosensitive sensor or the control unit on the one hand and the projection device on the other hand be positioned at different locations. The photosensitive sensor or the control unit could, for example, be positioned in the vicinity of the projection surface in the direction of the expected irradiation of the second light. In this way, the ratio between the second light to be detected and the unwanted ambient light resulting from the photosensitive sensor could be improved. In order to prevent the generation of the control signal even if the second light has actually exceeded the predetermined threshold value, the control unit in one embodiment, a microchip or other Rechenbzw. Storage unit, which serves to determine from the nature of the incident second light, in particular from the sequence and duration of pulses of the second light, whether it is the second light to desired or unwanted second light.

The desired second light is to be understood as meaning light which is intended to generate the control signal. By contrast, unwanted second light should not be used to generate the control signal, but would in principle be sufficient on account of its light intensity or intensity or quantity. If, for example, the desired second light is a flash, then any pre-flashes that may occur are to be understood as unwanted second light.

The arithmetic unit can be programmed so that they are stored on the durations and sequences of pre-flashes, which generate in a certain period of time usually on the market flash devices or cameras, so that the control unit can distinguish between pre-flashes and actual flashes. Only in the presence of an actual flash, that is a desired second light, would the control unit in this embodiment then generate the signal for activating the light source.

In order to accommodate a template with a motif of the graphic representation to be projected as simply as possible in the projection unit, the projection unit in a variant has such an accommodation or recording for a template of the graphic representation to be projected. This accommodation can be designed in such a way that an ordinary 35 mm film can be stored in the accommodation. It is also conceivable that the accommodation is designed to accommodate glass plates or other carriers with corresponding motifs for graphic representations to be projected.

In an alternative embodiment, the accommodation is designed in such a way that documents can be interchanged between graphic representations to be projected, without opening the projection unit. In particular, the accommodation and / or the template in this variant is designed so that the presentation of a first to be projected graphic representation against the presentation of a can be replaced with another graphic representation to be projected without removing the template of the first graphic representation to be projected from the projection unit before the presentation of the other graphic representation to be projected is introduced into the projection unit (this template is already included in the projection unit in this variant before being used).

That is, the originals of the graphic representation (s) to be projected are contained in the projection unit from the beginning and can be displaced by a relative movement of the original with respect to an opening region of the optical path in the projection unit. If the original is a standard 35 mm film, a simple document can be used to replace a first original with another original. Likewise, it is possible to bring back the first template instead of the other template in the opening area of the beam path. Through numerous different templates for images to be projected, an entire image series can be projected onto the projection surface, if a corresponding document transport is provided. This template transport can for example also be done by a controller on the part of the control unit. Likewise, a manual document transport is conceivable and possible.

In a development of the projection unit, this has a second housing for a second template. In this case, the projection unit is preferably designed such that the projection surface can be viewed superimposed with the second template via the projection unit. For example, the projection unit can provide a viewing window in which the projection surface is shown and overlaid with the motif of the second template.

In a design example based thereon, the second template is introduced via the second housing into a viewfinder beam path for a viewfinder or an eyepiece of the projection unit. This allows the projection surface on which the first original is to be projected to be superimposed on the second template in the viewfinder.

Preferably, the first and second templates are identical or the second template shows the outlines of the motif of the first template. Such is the viewfinder of

Projection unit to target the projection surface in the desired manner, so that the graphic representation of the first original to be projected can be aligned on the projection surface before it is projected onto the projection surface.

In such an embodiment, a semitransparent inclined mirror is inserted into an optical beam path for the projection of the graphic representation of the first original. This semi-transparent mirror allows light emitted by the light source to pass through unhindered, but reflects light coming from the projection screen in the direction of the viewfinder. The optical viewfinder beam path thus formed extends at an angle relative to the optical beam path for projection of the graphical representation as a function of the inclination of the mirror and is usually perpendicular to the optical beam path. In the viewfinder beam path, the second template is then accommodated between the mirror and the viewfinder, so that the projection surface can be viewed superimposed with the second template in the viewfinder.

Instead of a semipermeable mirror may alternatively be provided a conventional pivotable mirror or the semi-transparent mirror is additionally arranged pivotably. Such a mirror is pivoted for viewing the projection surface with superimposed second template in the optical beam path for the projection, so that an optical viewfinder beam path is available. In the projection, however, it can be removed from the beam path for the projection, so it is zurückverschwenkt or folded.

In one embodiment, the device has an adapter unit, in particular on a rear side of the projection unit, by means of which the light source can be connected in a simple manner to the projection unit. In this case, the rear side of the projection unit is understood to be the side that faces away from an exit opening of the projection unit, through which light beams exit from the projection unit.

A particularly simple connection between the light source and the projection unit by means of the adapter unit is possible, for example, when the adapter unit is designed to form a plug connection between the light source and the projection unit. In this case, the light source can simply be plugged into the adapter unit, thereby firmly connecting it to the projection unit. In a variant, additional fixing elements may be provided, the one prevent accidental removal of the light source from the adapter unit. This is possible by means of conventional crimping, clamping or screw connections.

In order to produce light with as high a degree of diffusion as possible, that is to achieve a balanced illumination of the original with the motif of the graphic representation to be projected, the adapter unit in an alternative embodiment has a corresponding element for increasing the degree of diffusion of light. As such an element, for example, serve an ordinary screen. Light that shines with a certain degree of homogeneity on an element to increase the degree of diffusion is converted by this element into light with a higher degree of homogeneity. Technically conditioned

Illumination differences of an object irradiated by the light source can be reduced in this way.

In order to achieve a good magnification of the motif on the original of a graphic representation to be projected, the optical beam path of the projection device preferably has an objective. This lens provides a corresponding magnification of the subject, so that the projected graphical representation is larger than the subject of the template. The magnification is set via the focal length of the lens, focal lengths of, for example, about 30 mm, about 35 mm, about 50 mm, about 70 mm, about 80 mm, about 100 mm, about 200 mm, about 300 mm, approx. 400 mm, approx. 500 mm are examples of possible focal lengths. The smaller the focal length, the higher the degree of magnification. The smaller the magnification of the projected graphic representation, the greater the intensity of the projection per area, while the light intensity of the light source remains the same. This means that a lower magnification results in a more focused and therefore brighter projection. This is particularly advantageous in bright ambient light.

In order to achieve the simplest possible configuration of the projection device, the projection unit in a variant has a camera, in particular a single-lens reflex camera. With such a configuration, it is possible to manufacture the apparatus for projecting a graphic image using a standard component (namely, the camera).

For ease of operation and better attachment of the device for projection of a graphical representation, the device in an alternative Embodiment, a holding element, which serves to hold the device by a user and / or for fastening the device on a tripod. This holding device can for example be attached directly to the projection unit. The mounting location of the retaining element is designed, for example, according to the center of gravity of the entire device for the projection of a graphical representation. In this way it can be prevented that the device tilts undesirably in one direction or the other or can be handled only with difficulty.

So that the graphic representation to be projected on the projection surface is only visible for a limited period of time, which is so short in particular that a human eye scarcely or not at all perceives the projected graphical representation, the light source is preferably designed in such a way after activation by the human eye Control signal light within a period of less than a second, in particular about 1/30 second, 1/60 second, 1/125 second, 1/250 second, 1/500 second or 1/1000 second to provide and send out. After expiration of this emission time frame, the light source is again in the deactivated state and can - if necessary after a predeterminable relaxation time, within which a control of the light source by the control signal has no effect on the

Light source exerts - be activated by a new signal emitted by the control unit control signal.

For example, to enable the aforementioned relatively short activation times of the light source, the light source in one embodiment is a flash unit or a plug-on flash. Hereby, it is possible to use a flash device commonly used in photography. Depending on the desired light color for the projection different flash tubes can be used. So would also be e.g. an infrared flash possible.

Alternatively, in one embodiment, instead of a conventional flash device, a laser is used as the light source. The laser light emitted by a laser is already very strongly directed. Additional mirrors and / or lenses can therefore be dispensed with, which might be necessary when using conventional flash devices, eg with a xenon light tube, in order to enable high-contrast projections onto a far-off projection surface. This is accompanied by the realization of smaller designs for the device according to the invention, since thus fewer electronic and optical components are required.

Also, when using a laser as a light source, a longer operation time is possible in a battery or battery operation, or more projections can be made than with a flash unit. There is no need to recharge a capacitor of the flash unit and the device is immediately ready for operation after a projection.

The object underlying the invention is also achieved by a method for the projection of a graphical representation on a projection surface using a projection device having the features of claim 16. In such a method, a graphic representation of the projection device is projected onto a projection surface only if an incidence of second light is detected by the projection device. The threshold from which an incidence of second light can be spoken is predeterminable. That is, not every incidence of second light leads to a projection of the graphical representation, but rather a certain threshold must be exceeded. Instead of an absolute intensity of second light, a change in the intensity of second light, which acts on the projection device, can lead to a projection of the graphical representation onto the projection surface.

The embodiments of the device for the projection of a graphical representation onto a projection surface, which are explained above, are - as far as technically possible - also applicable to the method explained below. The same applies in the reverse case.

In one configuration of the method, the second light at the location of the projection device or at the location of a light-sensitive sensor arranged on the projection device is brighter than an ambient light existing substantially simultaneously there. That is to say, by means of an additional light source compared to a previous state, a second light is emitted which triggers or triggers a projection of the graphical representation onto the projection surface. In an alternative embodiment, the method is carried out using a projection device according to the above explanations, optionally in a variant or alternative embodiment.

In order to enable a particularly simple projection of the graphical representation, in a variant of the method, light is used whose wavelength lies in the range visible to humans, that is to say at approximately 400 nm to approximately 800 nm. Alternatively, it is basically also possible to use light of a different wavelength. Thus, for example, photosensitive sensors of digital cameras are also sensitive in the infrared range of the electromagnetic spectrum, so that a corresponding graphical representation can indeed be perceived by a digital camera, but not by a human observer.

In a variant of the invention, the second light, whose incidence is detected by the projection device in order to project the graphical representation onto the projection surface, also has a wavelength in the visible range. By selecting suitable photosensitive detectors, however, detection of light having a wavelength of less than about 400 nm or greater than about 800 nm is also possible in principle.

In a variant of the method, the second light is a flashlight of a camera. That is, whenever a flashlight of a camera is fired, the graphic image is also projected onto the screen.

Incidentally, when the term "graphical representation" is used, it is always assumed that this graphical representation is a variable graphical representation, that is to say different motifs can define the graphical representation simultaneously or in chronological order Representation "does not have a fixed, invariable meaning in relation to a motive, but can manifest itself in various embodiments when the method is used. As a graphical representation in the context of the present invention, each graphic element, in particular an image, a photograph, a drawing, a character, a letter, a word, a plurality of words, a sentence formed from characters, letters and / or words and combinations of these examples understood with each other and / or with similar graphical elements. In an alternative embodiment of the method, a surface which at least partially constitutes a motif of a photographic image is selected as the projection surface. In other words, the subject of the projected graphic representation is additionally applied to this motif of a photographic photograph. In this way, a - in particular short-term - modification of the projection surface is achieved without leaving traces on the projection itself. In this way, a temporary modification of the projection surface which can not be detected directly on the projection surface is thus made possible.

In a further variant of the method, the projection of the graphical representation onto the projection surface and the production of the photographic image of the motif take place substantially simultaneously. At the same time, such a temporal coincidence of the projection and the production of the photographic image is understood to mean that the projected graphic representation becomes part of the photographic image. It is irrelevant whether during the entire period of the photographic exposure (for example 1/125 second) the corresponding graphical representation is projected onto the projection surface or only during a part (for example during the first 1/250 or the last 1/250 second) the exposure time required to produce the photographic image of the subject is followed by a projection of the graphic image onto the projection surface.

In a further variant of the method, the second light is a flashlight of a camera, this camera also serves to create the photographic image of the subject. That is, when the camera is fired to take a photographic shot of the subject and at the same time

Flash activated, this automatically leads to the projection of the graphical representation on the screen. In this way, it is particularly easy to synchronize between the creation of the photographic recording and the

Projection of the graphic representation on the projection surface to achieve. So can be advantageously ensured that the graphic to be projected

Representation actually exists on the projection screen when the photographic

Recording is created.

As a result, the photographic image of the subject in this variant, in addition to the actual subject at least a part of the projected graphical representation on. Due to the short projection time, this superimposition of the photographed motif and the projected graphical representation is hardly perceptible to a human eye during the time the photographic image was taken, but becomes visible at a later time when the photographic image or the photograph is viewed.

On the basis of the embodiment variant explained above with a laser as the light source, it is also possible to project graphic representations with light of selected wavelengths onto a projection surface in a targeted manner. Thus, a projection with invisible infrared laser light would be feasible in a simple manner. Such a projection with infrared light is detected by many cameras when taking a photographic shot, although it is invisible to the human eye.

The device according to the invention is particularly suitable for modifying a projection surface in such a way that the projection surface is at least partially given a historical appearance and / or is provided with an advertisement, an indication and / or a request, ie data, if a photographic image

Recording at least a portion of the screen is created. This is especially possible when the photographic image is taken using a flashlight which serves as a second light for activating the control unit of the

Device for projection is done. As a result, the photographic image of the projection surface thus created at least partially reflects the historical

Appearance, advertising, hint and / or solicitation, so additional

Data, on. It is immediately apparent that, in addition to the previously mentioned projectable elements or visual modifications of the projection surface, further comparable modifications are possible which have not been explicitly explained here.

Further variants and details of the present invention will be explained in more detail with reference to the following figures and examples. Show it:

1 shows an embodiment of a device for projecting a graphic representation onto a projection surface,

FIG. 2 shows a schematic representation of an exemplary use of the device of FIG. 1, FIG. FIG. 3 is a block diagram for explaining events occurring when using the apparatus of FIG

FIG. 4 shows two diagrams of the photosensitive sensor of FIG

Device of Figure 1 in an exemplary use acting amount of light as a function of time.

Figure 5 is a schematic exploded view of an embodiment of the device with a in a

Viewfinder beam path of the projection unit arranged second template;

FIGS. 6A-6B show two further schematic exploded views with a laser as light source;

Figure 7 is a schematic exploded view of another

Embodiment variant with a laser as a light source and via Galvometerantriebe moving deflection mirror for aligning the light emitted by the laser light;

Figure 8 shows a further embodiment variant with a laser as

Light source in accordance with Figures 5-7 matching view and with a deflection of the laser emitted light via piezo crystals.

1 shows an exploded view of a device for projecting a graphical representation on a projection surface with a Aufsteckblitz 1 as a light source, which is inserted into a slip-2 as an adapter unit. This slip-on device 2 is screwed to the rear wall 3 of a single-lens reflex camera 4 as part of a projection unit. Other connections between the slip-on device 2 and the rear wall 3 would also be possible.

In the rear wall 3, a ground glass 5 is inserted in a central and fully enclosed by the slip-on device 2 area, through which of the

Aufsteckblitz 1 emitted light in the interior of the SLR camera 4 can pass. The rear wall 3 is in the usual way on the SLR camera. 4 attached, that is, it can be opened by an opening mechanism not shown and pivoted to the SLR camera hinge means, so that the interior of the SLR camera 4 is accessible.

In the SLR camera 4, an exposed and developed slide film 6 is arranged in a conventional manner, that is to say in a film recording, which serves as accommodation. If necessary, this slide film 6 can be replaced by another slide film, so that in principle an unlimited number of motifs located on slide films can be introduced into the SLR camera 4. On the slide films 6 numerous motifs 7, which serve as a template for projecting graphics or images, arranged. The relative position of the subject 7 relative to the SLR camera 4 determines whether this subject 7 or another subject is projected. As is immediately apparent to the person skilled in the art, the motif 7 can always be projected, which is located in a central alignment between a first side 40 and a second side 41 of the SLR camera 4. In this central orientation, the motif 7 lies in an optical beam path 8 which is sketch-like in the figure 1 on the basis of an optical axis.

Instead of a slide film 6, any other suitable projection template or any other suitable template memory for the provision of a motif 7 can be used. Thus, in particular, digital projection templates, such as, for example, a thin-film transistor (TFT) display, which is known to the person skilled in the art from projector projection technology, are also suitable as a projection template.

The optical beam path 8 begins at Aufsteckblitz 1, passes through the ground glass 5 and the subject 7 of the slide film 6 and other optical elements of the SLR camera 8, in particular a arranged on the front of the SLR camera 4 lens 9, which also represents a part of the projection unit. A mirror of the SLR camera not shown in FIG. 1 can be pivoted into the optical beam path 8 in such a way that it is possible to look through a viewfinder 10 and the objective 9 at a projection surface. That is, there is a deflection of an incident light beam on a prism in order to facilitate the focusing of the graphic representation to be projected on the projection surface. In this way it is possible to align the entire device for the projection of a graphic representation with respect to the projection surface. Alternatively, it is also possible to remove the Aufsteckblitz 1 of the rear wall 3 and arranged thereon Aufsteckvorrichtung 2 for focusing or aligning. One then sees a projection of the subject 7 on a screen which is masked by the motif 7 on the slide film 6. By a arranged in the beam path 8 lens, however, the image on the ground glass is shown horizontally and vertically mirrored. Aligning and focusing using the viewfinder is therefore usually easier to perform.

In operation, the mirror of the SLR camera 4 is rotated from projection to projection or in particular over a period of several projections period in a second state, so that light from the Aufsteckblitz 1 along the optical beam path 8 from the lens 9 can emerge at the front.

On a mounted on an upper side of the SLR camera 4 accessory shoe 1 1, a control unit 13 is arranged by means of an accessory shoe connector 12, which includes a flash sensor and a flash control. The control unit 13 has on its upper side a light-emitting diode 14, which indicates the functionality of the control unit 13. Furthermore, a first regulator 15, a second regulator 16 and a third regulator 17 are formed on the upper side of the control unit 13.

By means of the first regulator 15, the so-called flash break, a parameter for determining the time which elapses between the detection of a flash and the triggering of the Aufsteckblitzes 1, can be set.

The second controller 16 is used to set the parameter of the number of flashes, that is, the number of control signals sent by the control unit 13 to the Aufsteckblitz 1 to generate one or more (for example, five or ten) flashes. By varying the parameter of the number of flashes, image series can be projected.

The third controller 17 is used to set the parameter of the time interval between two consecutive flashes. This parameter is of interest when the flash count parameter is set to two or more flashes.

The parameters which can be set by the first regulator 15, the second regulator 16 and the third regulator 17 are only to be understood as examples. Basically, other parameters can also be selected and set to trigger the Aufsteckblitzes 1 at an appropriate time to achieve. For example, it is also conceivable to determine the suitable triggering time by means of a computer program which can determine and store suitable parameters itself.

On the back of the control unit 13 facing the Aufsteckblitz 1 a test button 18 is arranged, by means of which even without the action of light on the control unit 13, a control signal can be generated to trigger the Aufsteckblitz 1.

The control unit 13 is usually connected by means of a connecting cable, not shown, with the Aufsteckblitz 1, so that a forwarding of the part of the control unit 13 generated control signals to the Aufsteckblitz 1 takes place.

On the front side of the control unit 13, that is, on the side which is arranged to the lens 9 of the SLR camera 4, the control unit 13 has a light inlet opening 19, via which a light-sensitive sensor arranged in the control unit 13 is supplied with light.

To hold the entire device for the projection of a graphical representation, a pistol grip 20 is attached as a handle on the underside of the SLR camera 4, which can be held by a user directly by means of a hand or can be connected to a stand, not shown.

For operation of the projection device, the entire device is first aligned with the aid of the viewfinder 10 in such a way with respect to a projection surface that the graphic representation to be projected at the desired location on the

Projection surface can appear. In this case, preferably also a focusing of the graphic representation to be projected takes place. Subsequently, the mirror of the

Mirror reflex camera 4 folded manually, so that the beam path 8 can be irradiated by emitted from the Aufsteckblitzes 1 light. As a result, no additional time is needed later for a flip-up of the mirror in the moment in which the graphic representation is to be projected onto the projection screen. Now, by means of the light-sensitive sensor arranged in the control unit 13

If a second light, in particular the incidence of a flash light, is detected, a control signal is generated by the control unit 13. This control signal is from the control unit 13 by means of a not shown electrical line to the

Aufsteckblitz 1 sent, causing this Aufsteckblitz 1 is triggered. This will the motif 7 is projected along the optical beam path 8 through the objective 9 onto the projection surface. If the light pulse detected by the control unit 13 was caused by a flash generated by a camera directed onto the projection surface, this camera now records not only the pure projection surface, but additionally the graphic representation projected by means of the projection device.

In an alternative embodiment, it is also conceivable that the control signal is transmitted to the SLR camera 4 via a contact made by means of the accessory shoe connector 12 and the accessory shoe 11 and effects subsequent actions there.

In order to ensure projection of the graphical representation on the projection surface only in the presence of an actual flash, but not in pre-flashes, the control unit 13 has a microchip which can distinguish pre-flashes from actual flashes. If now a sequence of pre-flashes with a subsequent correct flash is generated by means of a camera, the control unit 13 sends a control signal to the SLR camera 4 and the plug-on flash 1 only when the correct flash is present. It can thus be ensured that during the actual photographing process, that is to say when the photographic image of the projection surface is created, the motif 7 is already projected thereon as an image.

In an unillustrated modification of the projection device of FIG. 1, the SLR camera 4 has some deviating details. Thus, the SLR camera 4 is electronically controllable in this modification, so that an automatic film transport is possible. As a result, different motives 7 can be projected in quick succession on a projection surface in rapid succession. This is of particular interest when working in situations where a "flashing lightning storm" occurs, ie a rapid succession of flashes from different sources an endless loop is running, so that no rewinding of the slide film is required and the slide film contained in the SLR 4 also does not have to be replaced with another slide film or another template memory.

Also, in this modification, an autofocus system of the SLR camera 4 is present. This makes it easier and faster to focus. FIG. 2 shows an example situation which illustrates a possible use of the device for the projection of a graphic representation of FIG. 1, which is referred to below as a projection device. In this respect, reference is made to the explanations of Figure 1 reference. In principle, another projection device according to the invention can also be used in this example situation.

The projection apparatus 100 from FIG. 1 is mounted on a stand 101 in front of a wall

102, where a painting 103 hangs. In this case, the projection device 100 is aligned with the wall 102 such that a graphical representation 104, whose

Template is stored in the projection device 100, can be projected onto the wall 102 and at least partially on the painting 103. It is also conceivable that the projection takes place completely on the painting 103.

If a photographer 105 with a flashlight camera 106 photographs the painting 103, the light-sensitive sensor of the projection device 100 registers the flashlight of the camera 106 as a second light, whereupon the control unit of the projection device 100 sends a signal for triggering the flashing light of the projection device. This activates the plug-on flash and projects the graphical representation 104 onto the wall 102 and the painting 103.

The small representations shown in the lower right-hand corner of FIG. 2, which are labeled with the Roman numerals I, II and III, reproduce various elements or stages when the projection apparatus 100 is used.

Thus, the representation I of Figure 2 shows a consisting of the painting 103 and the wall 102 motif, as it sees the photographer 105 when looking through the viewfinder of his camera 106.

The illustration II of FIG. 2 shows the motif 107 present in the projection device 100, which is to be projected as a graphic representation 104 onto the wall 102 and the painting 103.

Finally, the representation III of FIG. 2 shows the image 108 which the photographer 105 actually takes with his camera 106. It consists of the wall 102, the painting

103 and the motif 107. FIG. 3 shows, with reference to the description of FIGS. 1 and 2, a block diagram for explaining characteristic events which take place when using the device of FIG. The use can be made, for example, according to the explanations to FIG. Reference numerals used in the description of Figures 1 and 2 are also used herein.

Upon actuation of a trigger 109 of a camera 106, the camera body 110 incorporating an analog or digital photosensitive element (for example in the form of a negative or transparency film or a complementary metal oxide semiconductor (CMOS) element or a charge coupled device (CCD) )), an electrical signal for triggering a flash 11 1 generated. The flash 11 then emits second light which strikes both a painting 103 and a photosensitive sensor 1 13 belonging to a projection device 100.

This photosensitive sensor 113 sends an electrical signal to a processor 1 14, which like the photosensitive sensor 1 13 is part of a control unit 13. The processor generates an electrical signal to activate a Aufsteckblitzes 1, which emits a first light in the form of a lightning due to the activation. This first light hits successively on a ground glass 5, a subject 7 to be projected (which is stored on an analog or digital storage medium) and a lens of a lens 9 of the projection device 100. The first light emerges from the objective 9 and hits the projection device on the painting 103, which represents at least part of the projection surface.

Light reflected from the painting 103 comprises both the first light from the projection device 100 and the second light from the camera 106. The reflected light is directed by a lens in an objective 112 into the housing 1 10 of the camera 106 and strikes it there photosensitive element, whereby an image consisting of the painting 103 and the motif 7 projected thereon is produced.

In the block diagram of FIG. 3, the first light emitted by the pin-up flash 1 of the projection device 100 is marked with arrows which have a narrow hatching from bottom left to top right. The second light, which is emitted by the flash 11 of the camera 105, is marked with arrows, which have a narrow hatching from bottom right to top left. Electrical signals are marked by arrows that have a wide hatching from bottom left to top right. FIG. 4 shows two schematic diagrams of the quantity of light acting on the photosensitive sensor of the projection device of FIG. 1 in an exemplary situation of use. The upper diagram shows the amount of light f (x) as a function of time. The lower diagram shows the first derivative f (x) of the amount of light from the upper diagram and thus represents the slope of the function f (x).

As can be seen from the upper diagram, individual flashes 120 (pulses of second light) represent a time-limited increase in the total amount of light 121 detected by the photosensitive sensor. Depending on the total (absolute) detected amount of light 121, it is possible that at a flash 120 at a first time 122, a total amount of light 121 is detected that is lower than the amount of light 121 detected at a second time 123 to which no flash 120 is emitted from a flash unit. Therefore, difficulties may arise when only the absolute amount of light is detected and at the same time it is to be determined whether there is a flash or not.

However, if one deduces the function f (x), individual flashes 120 are easier to identify, since they are accompanied by a sudden change in the slope of the function f (x). By defining a threshold value 124 represented by a dotted line in the lower diagram of FIG. 4, whenever the slope of the function f (x) exceeds a certain value, a control signal for activating a light source for emitting a first light can be generated. The threshold value 124 is set so that it is substantially exceeded only in the presence of a lightning, but not in another increase in the amount of light.

Computer-aided analysis of the functions f (x) and / or f (x) makes it easier to detect and filter lightning from unwanted light. A program used for computer-aided analysis can be designed to be adaptive and store various typical "sensor deflections" (peaks of the derivative f (x)) recognizable so that the light source of the projection unit is reliably activated at the desired time.

FIG. 5 shows a device for the projection of a graphic representation in a schematic exploded view, in which, above all, the functional relationship of the components shown is to be illustrated. It can the device shown, as well as those of the following Figures 6A, 6B, 7 and 8, be designed according to Figure 1 or be implemented as a stationary or permanently installed device.

In accordance with FIG. 5, incident ambient light 1001 is detected by a light-sensitive sensor 1002, which is pivotably arranged here, and which, e.g. may be formed as a phototransistor and the light-sensitive sensor 1 13 may correspond. Such a sensor 113 or 1002 may moreover be coupled to an electrical high-pass filter. As already explained, inter alia, with regard to the preceding FIG. 4, in this way the total ambient light 1001 does not measure the total light values, but only very rapid light changes starting at a predeterminable rate of change.

If a preset threshold value is detected by the light-sensitive sensor 1002 and the control unit 1003 coupled thereto in the incident ambient light 1001 as the second light in the manner described above, the control signal is transmitted to the flashlight apparatus via an electrical connection line 1041. This flash unit is formed of a flash tube 1005 and a parabolic mirror 1006 which directs the light of the generated flash.

The control unit 1003 again has the necessary control electronics, for example for the sensor data evaluation, the generation of a lightning voltage and the triggering of the flash.

Along the optical beam path of the first light thus emitted by the flash tube 1005, a motif 1007 is again arranged as a template for a graphic representation to be projected. In this case, the motif 1007 is accommodated in or in the projection unit in a first housing, not shown here, in accordance with the preceding embodiments. The subject 1007 may be a slide, a stencil, an exposed film, or a digital projection template, as discussed above. For the formation of the motif 1007 as a digital projection original, it is connected to the control unit 1003 via a further connecting line 1042, so that the control unit 1003 can control the motif 1007.

Along the optical beam path, a lens formed from a plurality of lenses 1091, 1092, 1093, 1094 for focusing and zooming the subject 1007 on the not shown here projection surface. The end of the optical beam path emanating from the flash tube 1005 forms the projection 1010 of the subject 1007 enlarged via the objective 1091-1094. The projection 1010 is consequently the projected graphical representation of the projection device shown, which was also designated 104 previously.

In the optical path is between the (first) lens 1091 and the subject

1007 a semitransparent mirror 1008 arranged. This semi-transparent mirror

1008 passes first light emitted by the flash tube 1005 unhindered, but reflects off the projection surface via the lens 1091-1094

Light. Due to the inclination of the semitransparent mirror 1008 by 45 degrees, this light coming from the projection surface is deflected perpendicular to the optical beam path upward as an optical viewfinder beam path.

This viewfinder beam path initially passes through a second motif 1011, which is accommodated in a likewise not shown second housing of the projection unit. This is followed by a ground glass screen 1012 and a lens 1013 along the viewfinder beam path, before the viewfinder beam path continues via a pentaprism 1014 to a viewfinder 1015. In this viewfinder 1015 associated with the projection unit, the projection surface with the superimposed motif 1011 is thus visible.

In this way, it is possible to see and aim the projection surface in the viewfinder 1015 while the projection unit is in a projection mode in which the projection of the subject 1007 onto the projection surface can take place.

In the embodiment variant explained above in connection with FIG. 1, the mirror 1008 had to be manually folded up during operation of the projection apparatus as part of the SLR camera 4, so that no light could be mirrored to the viewfinder 10 or 1015 via it.

Although the semitransparent mirror 1008 is still pivotable or foldable by 45 degrees, as shown by the arrows for the pivoting direction of the mirror 1008, the semitransparent mirror 1008 is shown in FIG. However, flipping the mirror 1008 to project a graphical representation or generate the projection 1010 is no longer mandatory. FIGS. 6A, 6B, 7 and 8 show alternative variants of a projection apparatus in which a laser 1050 is used as the light source for the first light instead of a flash unit. The advantages of a laser as a light source are seen in the fact that laser light is already very strongly directed from the outset and therefore does not have to be directed via mirrors and / or lenses in order to enable high-contrast projections on faraway projection surfaces.

Furthermore, much smaller designs can be realized with a laser as a light source, since fewer electronic and optical components are required.

Also can be made possible by the better energy yield more projections in a battery or battery operation of the projection device. Since no recharging of a capacitor as in a flash unit is necessary, the projection device is ready for use immediately after a projection.

In addition, working with laser light also allows projecting with light of very specific wavelengths. Thus, e.g. be projected with invisible infrared laser light. Infrared light is recorded by many cameras, although it is not visible to the human eye.

FIG. 6A shows a first embodiment variant with a laser 1050 as the light source for the first light.

In accordance with FIG. 5, ambient light 1001 initially also falls on the photosensitive sensor 1002, which is coupled to the control unit 1003. Via the electrical connection line 1041, the control unit 1003 controls the laser 1050, which emits a laser light as the first light.

The laser light is widened via a pair of laser lenses 1089, 1090 before it hits the subject 1007, which is again controllable via the connecting line 1042 with the control unit 1003.

The optical beam path of the laser light here runs in a straight line and following the subject 1007 in the known manner through the lens of the projection unit formed via the lenses 1091, 1092, 1093 and 1094 in order to produce the projection 1010 on the targeted projection surface. FIG. 6B shows a modification of the embodiment of FIG. 6A. Otherwise, the 1007 creative is replaced by a 1007 ^* creative.

The motif 1007 ^* here is, for example, a specular holographic representation or a micromirror array or a DMD or DLP chip (micro-mirror actuator), which can also show a calculated holographic interference pattern. In contrast to the embodiment of FIG. 6A, the subject 1007 ^* deflects the laser light emanating therefrom before it hits the objective 1091-1094.

With the figure 7, a projection 1010 is generated with a laser 1050 according to the X-Y scanner principle. For this purpose, in addition to the connection to the laser 1050, the control unit 1003 is connected via the connecting line 1041 via the connecting line 1042 to a Y-galvometer drive 1700 and via a third connecting line 1043 to an X-galvometer drive 1900.

The Y-Galvometerantrieb 1700 controls a directly illuminated by the laser 1050 with laser light pivotable mirror 1600, which deflects the laser light about a first axis. In contrast, the X-galvometer drive 1900 controls a second pivotable mirror 1800, which redirects the laser light reflected from the first mirror 1600 about a second axis that is perpendicular to the first axis.

By means of the rapid adjustment of the two mirrors 1600 and 1800 via the two galvometer drives 1700 and 1900, a projection 1010 can be produced without a motif 7, 107, 1007 or 1007 ^* having to be positioned in the beam path of the laser light. In this case, the laser light is reflected in such a rapid sequence via the mirrors 1600 and 1800 to different points of the projection surface, so that a seemingly stationary image is produced as a projection 1010.

A further alternative is shown in FIG. 8, in which apart from the photosensitive sensor 1002, the control unit 1003 and the laser 1050 connected to the control unit 1003 via the connecting line 1041, only one piezo-mirror 1060 is provided.

This piezo-mirror 1060 is connected via the connecting line 1042 to the control unit 1003, which thus takes over the control of the designed as a piezo-two-axis tilt mirror piezoelectric mirror 1060. The piezo-mirror 1060 has piezo crystals, which are tiltable about the application of an electrical voltage about two mutually perpendicular axes.

By means of these tiltable or adjustable piezoelectric crystals, the laser light incident on the piezoelectric mirror 1060 by the laser 1050 is used to reflect the laser light in rapid succession analogously to the mode of operation of the exemplary embodiment of FIG. 7 in such a way that the projection 1010 is produced ,

As will be apparent to one of ordinary skill in the art, the embodiments of FIGS. 5-8 may of course be combined at least partially with one another and with the design of the projection apparatus of FIG.

The following are examples that further illustrate the possible use of a device to project a graphical representation onto a screen. These examples are merely illustrative and are not intended to limit the scope of the claims.

Example 1 A projection apparatus according to the embodiment of Figure 1 is directed to an exterior facade of the Reichstag building in Berlin. In the SLR of the projection device is a slide film containing different motives. Among other things, the motif of rising flames and Philipp Scheidemann at the promulgation of the Republic on November 9, 1918 on the slide film is included.

If somebody photographs the Reichstag facade with a flash, the control unit of the projection device registers this incidence of light and in turn projects the selected motif onto the Reichstag exterior facade. A photograph of the Reichstag exterior façade then shows not only the actual façade, but also flames rising from a window or Philipp Scheidemann, who calls out the republic from a window of the Reichstag.

In this way, different historical moments of the Reichstag building can be illustrated in a particularly vivid way. It is possible to make the projection of the selected motifs only against payment of a fee; This could be particularly popular with tourists. Example 2

A projection device according to the embodiment of Figure 1 is directed to the outer facade of the Red Town Hall in Berlin. In the process, the entrance portal of the Red Town Hall is targeted. If somebody is photographing the Red City Hall, the photographer's lightning flashes the projection of a motif onto the portal of the Town Hall analogously to Example 1. For example, this theme could be the phrase "poor but sexy".

In this way, it is possible to reflect current affairs or satirical comments.

The same can be achieved, for example, with the sentence "I am a Berliner" when projecting onto a part of the outer façade of the Schöneberg town hall in Berlin to commemorate the visit of the former American President John F. Kennedy in Berlin.

Example 3

At frequently visited by foreign tourists places just as frequently photographed subjects can be modified by a projection device according to the embodiment of Figure 1 in the desired manner. That is, when tourists photograph a popular subject, a reference to past or current, possibly political, topics of contemporary history by a corresponding projection is pointed out, for example, in their national language.

That is, the actual photo subject is modified for the period of a photographic shot such that photographic images taken from the photo subject additionally contain the projected subject (the projected graphic image). If a lot of flash photography is done by a particular subject at the same time, it is conceivable that not every one of these photographs will contain the projected graphical representation. However, part of the photographic images taken contain the projected graphical representation.

Example 4

At a press conference, a projection apparatus according to the embodiment of Figure 1 is directed to an explanatory person.

Numerous photographic shots with flashlight during the press conference lead to a frequent increase of the control unit Light intensity, so that numerous control signals are sent to the Aufsteckblitz. As a result, the graphic representation to be projected is repeatedly projected onto the person giving the explanation.

As a result of the prevailing "flash of lightning", the additional projection of a graphical representation by means of a flash is inconspicuous.On many of the photographs taken by the person making statements in the press release, then an additional graphical representation is included, which is arbitrary selectable.

Example 5

A projection device according to the embodiment of Figure 1 is placed in a place near which the appearance of a moving object, such as a vehicle, is expected. The projection device will be aligned so that it will project a graphical representation on the moving object as it passes the projection device.

It is assumed that other photographic equipment are placed in the vicinity of the projection apparatus to also photograph the moving object. If a photographic image of the moving object is then made by using such a photographic device using a flashlight, the projection device is simultaneously activated by the flashlight and a corresponding graphical representation is projected onto the mobile object.

The photographic image of the movable object then contains, in addition to the movable object, the additionally projected graphical representation. Also in the context of this example, numerous applications, for example, for promotional purposes or historical commentary can be found.

_{* * * * *} LIST OF REFERENCE NUMBERS

1 plug-in flash

10 viewfinders

100 projection device

1001 ambient light

1002 Photosensitive sensor

1003 control unit

1005 flash tube

1006 parabolic mirror

1007, 1007 ^* (first) motif

1008 mirror

101 tripod

1010 projection

101 1 (second) motif

1012 ground glass

1013 lens

1014 pentaprism

1015 viewfinder

102 wall

103 paintings

104 Graphical representation

1041 connection line

1042 connection line

1043 connection line

105 photographer

1050 laser

106 camera

1060 piezo mirror

107 motif

108 photographed image

1089, 1090 laser lens

109 trigger

1091, 1092, lens

1093, 1094

1 1 accessory shoe

110 camera body 11 1 Flash of the camera

112 Lens of the camera

113 Photosensitive sensor

114 processor

12 accessory shoe connectors

120 flash

121 Absolute detected amount of light

122 First time

123 Second time

124 threshold

13 control unit

14 test light-emitting diode

15 First controller

16 second controller

1600 Y-mirror

17 Third controller

1700 Y-galvometer drive

18 test buttons

1800 X mirror

19 light inlet opening

1900 X-galvometer drive

2 clip-on device

20 pistol grip

3 Rear wall of the SLR camera

4 SLR camera

40 First page of the SLR camera

41 Second side of the SLR camera

5 screen

6 slide film

7 motif

8 Optical beam path

9 lens

Claims

claims

1. A device for projection of a graphical representation on a projection screen, with

a light source (1, 1005, 1050) for emitting a first light coupled with

a projection unit (3, 4, 9),

characterized,

in that the device has a control unit (13, 1003) with a light-sensitive sensor (1 13), which is provided and set up in response to a second light acting on the sensor (1 13)

Activation of the light source (1, 1005, 1050) to produce, wherein the light source (1, 1005, 1050) after the activation of the transmission of the first light back to a deactivated state.

2. Device according to claim 1, characterized in that the control unit (13, 1003) has a connecting element (12, 1002), which for connection to the projection unit (3, 4, 9) and for contact transmission between the control unit (13, 1003 ) and the projection unit (3, 4, 9) and / or the light source (1, 1005, 1050) is used.

3. Device according to claim 1 or 2, characterized in that the control unit (13, 1003) has a computing unit (114) which is provided and adapted to detect the action of unwanted second light on the control unit (13, 1003) and in the case of such interference of unwanted second light generating the control signal to

Activation of the light source (1, 1005, 1050) to suppress.

4. Device according to one of the preceding claims, characterized in that the projection unit (3, 4, 9) has a housing for a template (7, 1007, 1007 ^* ) to be projected graphical representation (104, 1010).

5. The device according to claim 4, characterized in that the accommodation is designed such that a template (7, 1007, 1007 ^* ) of a first to be projected graphical representation (104, 1010) by a template (7, 1007, 1007 ^* ) another graphic representation (104, 1010) to be projected can be changed without opening the projection unit (3, 4, 9), in particular without the template (7, 1007, 1007 ^* ) of the first graphic representation to be projected (104, 1010 ) from the projection unit (3, 4, 9).

6. Device according to one of claims 4 or 5, characterized in that the projection unit (3, 4, 9) has a second housing for a second template (101 1).

7. The device according to claim 6, characterized in that the projection unit (3, 4, 9) is designed such that the projection surface superimposed with the second template (1011) on the projection unit (3, 4, 9) can be considered.

8. Device according to one of the preceding claims, characterized in that the device on the projection unit (3, 4, 9) an adapter unit (2) for connecting the light source (1, 1005, 1050) with the projection unit (3, 4, 9 ) having.

9. Apparatus according to claim 8, characterized in that the adapter unit (2) is adapted to a plug connection between the projection unit

(3, 4, 9) and the light source (1, 1005, 1050).

10. Apparatus according to claim 8 or 9, characterized in that the adapter unit (2) has an element (5) for increasing the degree of diffusion of the first light.

1 1. Device according to one of the preceding claims, characterized in that the projection unit (3, 4, 9) has a lens (9, 1091-1094).

12. Device according to one of the preceding claims, characterized in that the projection unit (3, 4, 9) has a camera, in particular a single-lens reflex camera (4).

13. Device according to one of the preceding claims, characterized in that the device comprises a holding element (20) which is suitable for holding the device by a user and / or for attachment to a tripod.

14. Device according to one of the preceding claims, characterized in that the light source (1, 1005, 1050) is provided and arranged for the first light after activation by the control signal during a period of less than one second, in particular 1/30 Second, 1/60 second, 1/125

Second, 1/250 second, 1/500 second or 1/1000 second.

15. Device according to one of the preceding claims, characterized in that the light source (1, 1005, 1050) is a flash unit (1, 1005) or a laser (1050).

16. A method for projecting a graphical representation onto a projection surface using a projection device, characterized in that a graphic representation (104, 1010) of the projection device (100) is projected onto a projection surface (102, 103) only when the part

Projection device (100) an incidence of second light of predeterminable intensity or a predeterminable change in an intensity of second light is detected.

17. Method according to claim 16, characterized in that the second light at the location of the projection device (100) is brighter than an ambient light (1001) present there substantially simultaneously.

18. The method according to claim 16, characterized in that a device according to one of claims 1 to 15 is used as the projection device (100).

19. The method according to claim 16 or 18, characterized in that infrared light is used for the projection.

20. The method according to claim 16 or 18, characterized in that light is used for the projection, which has a wavelength in the visible range.

21. The method according to any one of claims 16 to 20, characterized in that the second light whose incidence is detected, has a wavelength in the visible range.

22. The method according to any one of claims 16 to 21, characterized in that the second light is a flash of a camera (106).

23. The method according to any one of claims 16 to 22, characterized in that a surface is selected as the projection surface (102, 103), which at least partially

Photograph of a photograph (108).

24. The method according to claim 23, characterized in that the projection of the graphical representation (104, 1010) on the projection surface (102, 103) and the creation of the photographic image (108) of the motif take place substantially simultaneously.

The method of claim 23 or 24, characterized in that the second light is a flashlight of a camera (106), the camera being used to create the photographic image (108) of the subject.

26. The method according to any one of claims 23 to 25, characterized in that the photographic image (108) of the motif additionally comprises at least a portion of the projected graphical representation (104, 1010).

27. Use of a device according to one of claims 1 to 15 for modifying a projection surface such that the projection surface (102, 103) at least partially then receives a historical appearance and / or - is provided with an advertisement, an indication and / or a request when a photographic image (108) of at least part of the projection surface (102, 103) is made, such that the photographic image (108) of the projection surface (102, 103) also includes the historical appearance, the advertisement, the hint and / or the Requesting.