EP2140195A1

EP2140195A1 - Micro-optical beam-forming array for projecting images of a divergent isotropic cloud of light points, primarily for the entertainment sector

Info

Publication number: EP2140195A1
Application number: EP08700871A
Authority: EP
Inventors: Ralf Violonchi
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-01-25
Filing date: 2008-01-16
Publication date: 2010-01-06
Also published as: WO2008089729A1; WO2008089729B1; US8300293B2; US20100002280A1

Abstract

The invention relates to a beam-forming array for projecting a divergent isotropic cloud of light points. Said array comprises a source (4) for emitting electromagnetic radiation, a receiving or connecting possibility for a power source (2), an electrical or electronic subassembly (5), and an optical unit (6) that is arranged in a housing (1) along with the radiation source (4). The radiation source (4) is a semiconductor diode laser or a light emitting diode (LED) while the optical unit (6) is composed of at least two superimposed and grid-shaped spectral films that are offset relative to each other or a diffractive optical element. The optical unit (6) limits the intensity of the emitted radiation and the distance of the light point beams relative to one another to a value that does not pose any risk to a human eye. The invention has the advantage of providing a miniature portable array that is inexpensive to produce and easy to handle for a large spectrum of indoor and outdoor uses in order to project any clouds of light points, particularly of real constellations.

Description

Micro-optical beam-shaping arrangement for image projection of a divergent isotropic light point cloud, primarily for the entertainment sector

The invention relates to a micro-optical beam shaping arrangement for image projection of a divergent isotropic light point cloud. The arrangement is particularly suitable for use in the entertainment sector.

For some time, beam-shaping arrangements for image projection of a starry sky have been known. They allow the generation of light point clouds on e.g. spherical or flat display surfaces. In general, the image projectors have the following design features: light source formed in the visible wavelength range, which is arranged upstream of a device arranged in the housing and introduced for beam splitting or beam forming, and a projection opening in a wall of the housing which enables the light point cloud to be emitted onto a display surface. The rays emanating from the image projector are emitted divergently. The spectral working range of the image projectors is generally between 0.38 μm and 0.78 μm. This allows an image representation over the entire visible spectrum.

The document DE 40 34 661 A1 is a small projector for imaging a cosmic object, such as a starry sky or the surface of a planet or satellite, on a screen with a rotating and from inside illuminated object sphere, on whose lateral surface is an object to be imaged by different light transmissivity performing object layer is described. In a true-to-life illustration, the almost uncut celestial hemisphere is projected on a flat screen in the right direction and over a large area. In this case, the stars are represented as light-permeable areas of an otherwise internally mirrored object layer, which is encased by a rotatable and translucent carrier hollow sphere and illuminated from the inside by a light source. The constellation of stars is taken off by an optical fiber package which conforms to the object layer, and the resulting primary image is either projected directly onto the room ceiling via a foil or via a lens.

DE 199 30 821 A1 discloses a device for generating light effects by means of a laser, in particular for show and stage effects, but also as a cost-effective alternative for conventional light sources for living areas with a laser and a deflection unit for the laser beam. The light effect device is a self-contained mobile device surrounded by a housing, of which a part of the inside of the housing is provided with a reflection plane of a mirrored irregular surface and another part of the housing surface is a transparent and rough projection plane for imaging an irregular image pattern.

DE 40 26 133 A1 discloses a device for the production of illuminated decoration, which consists of a housing and arranged in the housing illumination device, arranged in the front of the housing transparent cover and arranged between the illumination device and the cover, preferably with circular holes provided plate exists. The radiation passing through the holes of the plate is imaged on the cover in the manner of a starry sky projected on a plane.

DE 10 2005 037 435 A1 discloses a device for switchable image projection with diffractive optical elements, which uses its property of using laser beams by means of beam splitting and / or beam shaping for pattern and image generation. For moving the light beam over the diffractive optical elements, a lens and a mirror arranged in the focus of the lens are used. According to the prior art, three different embodiments of a beam-forming illumination arrangement for image projection of a light point cloud including a starry sky can accordingly be distinguished.

1. The use of an incandescent lamp as a radiation source. An incandescent lamp emits, in addition to the visible radiation, the much higher proportion of radiation in the near infrared range and can thus be viewed in simplified form as a temperature emitter. By introducing a selective shadow mask, certain areas of the emitted radiation can be masked out and a multi-beam light point cloud can be generated. This embodiment is normally unsuitable for mobile use due to the high power consumption and limited life of the bulbs. Another disadvantage is that due to the wave nature of the light, the image of small light openings is not contour sharp.

2. The use of a light emitting diode (LED) as a radiation source. An LED emits radiation in a limited spectral range, the emitted radiation is almost monochrome. The efficiency and the lifetime of this radiation source are much higher than with conventional incandescent lamps. A disadvantage is the relatively large extent of the radiation-emitting chip, so that an exact remote imaging of the radiation proves to be relatively expensive optically or for each light spot in each case a separate LED is necessary.

3. The use of a semiconductor diode laser as a radiation source. Diode lasers are among the most efficient radiation sources available today, with excellent efficiencies. Their high brightness, collima- bility and coherence allowed the generation of light effects by diffracting a coherent photon beam on an optical grating. Another advantage of laser beam sources is the approximately Gaussian intensity profile of the laser beam, which can be selectively modified in amplitude and / or phase via corresponding microoptical structures. The shaping of the complex intensity distributions of the laser beam takes place expediently via diffractive optical elements (DOE), so that corresponding image patterns are produced by beam splitting and beam shaping, which are produced via optical imaging elements which transmit the microoptical structures. downstream, a projection of an isotropic laser light point cloud can take place.

Of practical relevance are mainly the last two embodiments of the image projectors. Due to the advancing technical development, radiation sources with very high optical power are now available. Due to the increasing use of these radiation sources in conjunction with diffractive optical elements (DOE), the illumination intensity and the range of the beam-forming image projectors have been increased many times over. As a result, the risk of damage to the eye by laser image projectors has risen many times over, and the achieved performance values now exceed for the first time the legally required specifications for an eye-safe arrangement. Known beam-forming image projectors emit a high-intensity laser light point cloud, which generally presents a potential hazard to the human eye.

Corresponding image projectors are primarily used in the entertainment sector, so that by exposing the eye of the observer by means of the laser light point cloud a latent outgoing danger can be assumed when using beam-forming image projectors by means of semiconductor diode lasers to a considerable extent. Due to inadequate lighting conditions, such as are often desired when using beam-forming image projectors in the entertainment sector, the eye is adapted to the poor lighting conditions. This opens the iris to record as much residual light. The greater diameter of the iris is causally related to an increased likelihood of damage from laser radiation, as the laser radiation through the pupil is focused directly onto the retina, where it can lead to irreparable optical and thermal damage.

Due to the radiation intensity occurring, currently known beam-shaping laser image projectors for light point clouds must be predominantly classified as laser class 3B or are correspondingly poor in performance. Laser class 3B is the second highest risk level for laser systems. The emitted radiation is dangerous for the eye and often for the skin. It is required by law to register the operation with the responsible professional association and to order a laser safety officer in writing. By- Persons should always be kept away from the beam path, unless they wear suitable eye protection, protective clothing and protective gloves. The beam should be above or below eye level. Constructive measures, such as barriers and latches, which limit the horizontal and vertical pivoting range of the beam should be used. Furthermore, an identification of the hazardous area with standardized warning signs is required. When the laser device is put into operation, the emission of optical and acoustic signals is required for radiation warning. The laser device must have a key switch to protect the laser device against unauthorized use.

In practice, the operation of beam-forming laser image projection systems of the laser class 3B in compliance with the legal requirements can not be reasonably realized according to the prior art and contradicts the actual purpose of the arrangement.

The problem described above with the use of beam-shaping laser image projection systems clarifies an obvious need for action in order to minimize the risk to humans and animals.

The object of the invention is therefore to provide an eye-hazard-free beam-shaping arrangement for the projection of a divergent isotropic laser light point cloud, which allows the Einklassifizierung in a user-friendly laser class.

According to the invention, the object is achieved by a beam-shaping arrangement for the projection of a divergent isotropic light point cloud, consisting of a source for emitting electromagnetic radiation, a recording or connection possibility for an energy source, an electrical or electronic assembly and an optical unit, wherein the optical unit and the radiation source are disposed in a housing, and in which the radiation source is a semiconductor diode laser or a light emitting diode (LED); the optical unit consists of at least two latticed spectral foils positioned one above the other and offset from one another, or of a diffractive optical element, and the optical unit emitting the divergently emitted radiation in its direction intensity and at the distance of the light spot beams to each other limited to a value that does not pose a threat to a human eye.

The invention combines the advantage that for a wide range of applications in a miniaturized design, a cost-effectively manufacturable and easy to handle portable arrangement for the projection of arbitrarily designed light point clouds is provided without their application, the risk of injury to the human eye.

Preferred embodiments of the invention provide a radiation power of the semiconductor diode laser of at least 5 mW, preferably 10 mW to 500 mW, and that by forming the three-dimensional structure of the diffractive optics, the radiation intensity and the distance of the light spot beams to each other to a harmless to the human eye value limited are.

According to further particular embodiments of the invention, the arrangement comprises a protective glass mounted in front of the optical unit, a lens expanding the beam path is arranged in the beam path after the diffractive optics, which lens can also serve as a protective glass at the same time.

Another embodiment provides to limit the outer shape of the light point cloud by a preferably movable mechanical and acting as a shutter device.

According to one embodiment of the arrangement according to the invention, lattice-shaped spectral films are converted into a first spectral film, offset at an angle of 45 ° and / or 22.5 ° and / or 11, 25 ° and / or 5.625 ° and / or 2.8125 °, in front of the optical Unit positioned.

According to preferred embodiments of the invention, the electronic assembly comprises a microcontroller and a control unit for the radiation source, the recording or connection possibility for the power source is designed as a battery, accumulator or plug contact, the available capacity of the power source and operation of the radiation source is optically displayed, is the optical operating display as a single or multi-color LED display or as LC display executed, the housing has a diameter of about 8 mm to 30 mm and the radiation power of a light spot beam <1 mW.

A particularly preferred embodiment of the invention makes it possible to project by means of the arrangement a real constellation or several real constellations on an arbitrarily shaped surface or an arbitrarily shaped three-dimensional structure.

The invention will be illustrated in more detail with reference to a drawing. Show it:

Fig. 1 shows the basic structure of an arrangement according to the invention;

2 shows a component of the arrangement according to the invention;

Fig. 3 shows the representation of the mask of the diffractive optics used.

As can be seen from FIG. 1, in a housing 1, which preferably has a diameter of approximately 20 mm, a receptacle or connection possibility for an energy source 2, an operating element 3 and an electronic assembly 5 are arranged. The radiation emitted by the radiation source 4 is radiated through the optical unit 6 and leaves the housing 1 through the protective glass 7. In the present example, the radiation source 4 used is a semiconductor diode laser from the company Picotronic GmbH with a radiation power of 10 mW. The emitted radiation has a wavelength of 532 nm. As optical unit 6, a 16-stage diffractive optical system is used in this embodiment, whose three-dimensional structure has been formed by means known per se. The mask of the diffractive optics thus produced is shown in FIG. The diffractive optics modulate the amplitude and the phase of the radiation and thereby ensure that a hazard to the human eye is excluded. The diffractive optical element (DOE) 6 expands the radiation of the semiconductor diode laser in such a way that the sum of the intensities of the individual beams of the complex laser intensity distributions at a given distance of 100 mm is such that a pupil of an eye with a diameter of 7 mm only a maximum optical power of 1 mW can be radiated and thus the requirements of DIN 60825 are met. As a result, the Einklassifizierung the inventive arrangement despite significantly higher output power in the laser class 2 is possible. She is with it harmless to the eye and the user, in that case also not notifiable.

With the help of the limiting device 8 shown in Fig. 2, the exiting radiation of the radiation source 4 can be limited in their spatial extent to a desired shape. Thus, with the limiting device 8, whose legs are movably arranged, given to a starry sky emitted by means of the optical unit, the geometric shape of a Christmas tree and the starry sky are projected onto a natural fir tree. The device 8 can also be rotatably arranged above the diffractive optics and be designed, for example, as a spoke wheel, with the effect that the laser beams are interrupted for a very short time and thus a sparkling constellation is produced.

According to a particular embodiment of the invention, a widening lens, not shown here, can be positioned in front of the optical unit 4. This allows even with semiconductor diode lasers greater power, for example, of 40 mW or 80 mW, to expand the emitted radiation so that a safe application of the arrangement is possible. Such an expansion lens could also serve as a protective glass 7 of the arrangement.

Instead of a diffractive optics can also be used as an optical unit 4 per se known spectral films with a line grid to produce a starry sky. The spectral foils positioned at different angles to one another and above one another enable real constellations to be projected. By means of a further spectral film, which is rotatably arranged at a distance from already superimposed spectral films, a constellation with a sparkling effect can be projected.

REFERENCE SIGNS LIST

1 housing

2 energy source

3 control element

Radiation source electrical / electronic assembly optical unit

7 protective glass

limiting device

Claims

PATENT APPLICATIONS

1. beam-shaping arrangement for the projection of a divergent isotropic light point cloud, consisting of a source (4) for emitting electromagnetic radiation, a recording or connection possibility for an energy source (2), an electrical or electronic assembly (5) and an optical unit (6) in that the optical unit (6) and the radiation source (4) are arranged in a housing (1), characterized in that

the radiation source (4) is a semiconductor diode laser or a light emitting diode (LED);

the optical unit (6) consists of at least two superimposed lattice-shaped spectral films positioned offset from one another, or of a diffractive optical element, and

the optical unit (6), the divergently emitted radiation in their radiation intensity and the distance of the light spot beams each other limited to a value that does not pose a threat to a human eye.

2. Arrangement according to claim 1, characterized in that the radiation power of the semiconductor diode laser is at least 5 mW, preferably 10 mW to 500 mW.

3. Arrangement according to claim 1 or 2, characterized in that the diffractive optics is a 16-stage optics and by forming the three-dimensional structure of the diffractive optics, the radiation intensity and the distance of the light spot beams are limited to a harmless to the human eye value.

4. Arrangement according to claim 1 to 3, characterized in that the arrangement comprises a front of the optical unit (6) mounted protective glass (7).

5. Arrangement according to one of claims 1 to 4, characterized in that in the beam path after the diffractive optics, the beam path widening lens is arranged and this preferably also serves as a protective glass (7).

6. Arrangement according to one of claims 1 to 5, characterized in that the outer shape of the light point cloud by a preferably movable mechanical and acting as a diaphragm arrangement (8) is limited or the arrangement (8) rotatably arranged and preferably formed like a spoke.

7. Arrangement according to claim 1, characterized in that latticed spectral films offset to a first spectral film at an angle of 45 ° and / or 22.5 ° and / or 11, 25 ° and / or 5.625 ° and / or 2.8125 ° ago the optical unit are positioned.

8. Arrangement according to one of claims 1 to 7, characterized in that the electronic module (5) has a microcontroller and a control unit for the radiation source (4).

9. Arrangement according to one of claims 1 to 8, characterized in that the recording or connection possibility for the energy source (2) is designed as a battery, accumulator or plug contact connection and / or the available capacity of the energy source (2) and operation of the radiation source ( 4) are optically displayed.

10. Arrangement according to claim 9, characterized in that the optical operating display is designed as a single- or multi-colored LED display or LC display.

11. Arrangement according to one of claims 1 to 10, characterized in that the housing (1) has a diameter of about 8 mm to 30 mm.

12. Arrangement according to one of claims 1 to 11, characterized in that the radiation power of a light spot beam <1 mW.

13. Arrangement according to one of claims 1 to 12, characterized in that by means of the arrangement one or more real constellations on an arbitrarily shaped surface or an arbitrarily shaped three-dimensional structure can be projected (are).