LIGHTING FIXTURE HAVING A MECHANISM FOR PIVOTING AN ADDITIONAL OPTICAL COMPONENT INTO THE LIGHT BEAM

Field of the Invention

The present invention relates to a lens system comprising at least one lens, which lens system primarily applies for use in a light assembly comprising at least one light source, which generates a beam of light into light forming means and further through a front lens.

Background of the Invention

US 6,808,969 B2 concerns a first multiple lens array designed with positive-power lenses producing multiple bundles of converging light rays and a second multiple lens array designed with negative-power lenses producing multiple bundles of collimated light rays at a certain optimal separation between the two multiple lens arrays. As the axial separation between the two multiple lens arrays increases, the divergence of the entire beam of light increases.

The unpublished Danish patent application PA 2005 01465 relates to a method for forming a light beam and to a light assembly comprising at least one light source placed in conjunction with a fixed reflector, which reflector forms a beam of light into light forming means, which light assembly comprises a front lens, where the light forming means at least comprises a light deflecting means for changing the light angle of the light beam after passing through the front lens. The front lens has a central part that differs from the surrounding parts of the front lens, and where the light deflecting means in a first position concentrates the light beam into the central part of the front lens to generate a wide-angle light beam. Where the light deflecting means in a second position distributes the light beam over the entire front lens to generate a narrow-angle light beam, and where the light deflecting means is connected with a first actuator, and where the light deflecting means is movable between the first and the second position. A very efficient wash light zoom system can hereby be achieved, where the front lens has different characteristics between its centre portions and the rest of the surrounding part of the front lens. Because of the internal light deflecting means, the front lens does not have to be movable with respect to the housing. Furthermore, the reflector and the lamp are held in a fixed position. This may result in constant control of the air flowing around the optical components.

Object of the Invention

It is the object of the invention to achieve a lens system which can change between operation modes automatically by activating or deactivating activation means so as to change the performance of a light fixture.

Description of the Invention

This can be achieved with a lens system as described in the preamble of claim one and modified so that the lens system comprises at least one supplementary optical component, which supplementary optical component is moved in or out of the light beam by first actuating means, which first actuating means is moving the supplementary optical component in a rotating movement around a rotation axis from a first position outside the light beam into a second position in the light beam, which rotation axis has a direction mostly perpendicular to the light beam.

Hence it can be achieved that the supplementary optical component can be moved in and out of a light beam by activating the actuation means. This can lead to a change in the performance of a light assembly during operation. The supplementary optical component can in a very short time period be moved in or out of the light beam. For instance in a light assembly it would be preferred to stop the light performance before making the change. However, when switched on again the system will be ready in a few seconds or less. This is an alternative to the change of optical components, which has to take place when for instance light assemblies are moved from a stage ceiling to the floor, where the light assemblies have to be opened, and new optical elements have to be placed inside the light assemblies. Afterwards a test has to be carried out to make sure that the new optical components are correctly placed. The extra optical compo- nent could for instance be an extra zoom lens, which is added to a zoom lens group to change the total performance of the zoom lens group. By optimising the axis of rotation in relation to the lens group a relatively circular movement of the supplementary optical component can take place as part of a circle, which circle has a relatively small diameter. Thus, only limited open space in conjunction with the zoom lens system is necessary, when operating the supplementary optical component. The axis of rotation is placed relatively high in relation to the optical centre axis of the zoom lens system.

Preferably the supplementary optical component is connected to second actuating means for rotating the optical component in relation to the light beam. Thus, it can be achieved that the supplementary optical component can be rotated at first to achieve the optimal position. To achieve the optimal position a kind of position indicators can be placed on the rotating fixture of the supplementary optical component. Detection means can be placed in relation to the rotating part to indicate the actual position. In other situations particular optical effects can be achieved by letting the supplementary optical component rotate during operation. Hereby special light effects can be achieved, which light effects move in circular movements.

The supplementary optical component can be a beam shaper. Thus, the beam shaper can be moved in or out of the light beam, and during operation can the beam shaper be rotated into the correct position.

Instead the supplementary optical component can be a prism. Thus, a prism with special optical effect can be moved into the light beam on command, and sometimes it is preferred that the prisms rotate to achieve special light effects for instance multiple fixtures of the same fixture element frcm a light assembly.

The first and second actuating means can be step motors, which step motors are connected to belts to rotate the related components. This way it can be achieved that the step motors are computer controlled, and they can easily be controlled to stop when reaching a defined positions. Furthermore, the step motors are advantageous in that they are able to function as parking brakes to secure the position of the optical compo- nents.

The lens system can be a zoom lens system or a part of a zoom lens system, which zoom lens system can be moved between a first position and a second position by third linear actuating means. Thus, it can be achieved that the zoom lens system is movable so as to change the zoom performance of e.g. a light assembly and the supplementary optical component can automatically operate in all the different position of the zoom lens system.

The lens system may comprise a supplementary optical component in the form of full or partly coloured glass. This may be used for a full or a partly change of colour of a light beam generated from a light assembly.

As an alternative, the supplementary optical component may comprise an optical pattern. This may result in a light assembly that may generate a special light pattern which light pattern may be rotated by activating the step motor.

Description of the Drawing

Fig. 1 shows a front view of a zoom lens system 2. The zoom lens system comprises at least one lens 4, where the zoom lens system is movably mounted e.g. in a lighting fixture by means of sliding means 6 and 8 placed at a frame 7. The zoom lens system 2 comprises a supplementary optical component 10, which in fig. 1 is non-operational. The zoom lens system 2 comprises a first step motor 12 having a driving shaft 14 connected to a driving wheel 16, which wheel drives a belt 18. The belt 18 also drives a wheel 20, which rotates around a rotating axis 22. At the other side of the zoom lens system 2 a further rotational axis 24 is shown, connected to the frame 26 of which frame can rotate. A second step motor 28 rotates a driving wheel 30, which wheel is connected to a belt 32, which belt drives a wheel 34 which rotates the supplementary optical component 10. Furthermore, fig. 1 shows an electronic detection means 36, which detects the position of the supplementary optical component 10.

Fig. 2 shows the zoom lens system in a position where the supplementary optical component 10 is moving between a non-operational position and an operational position. The lens system 2 comprises at least one lens 4, and the lens system as such is able to slide by the means 6 and 8 placed in the frame 7. The supplementary optical element 10 is seen in a mean position. The step motor 12 rotates the wheel 16 around the axis 14 and pulls the belt 18 to move the supplementary optical component 10 by means of the driving wheel 20, which is indicated. The second step motor 28 can rotate the wheel 30 to move the belt 32, which rotates the supplementary optical element 10 by rotating the wheel 34. The belt 32 is cooperating with a pulling wheel 40 to achieve optimum belt tension. A mechanical arm 38 cooperates with detection means 36 to detect when the supplementary optical component is operating.

Fig. 3 is a side view of the zoom lens system 2, where the supplementary optical component 10 is in operating position. The zoom lens system 2 is still able to be moved in longitudinal direction by means of the sliding means 6 and 8. The motor 12 stands still as the optical component 10 is in its operating position. The second step motor (not seen) can drive the wheel 30, and the belt 32 to rotate the supplementary optical component 10 by means of the wheel 34. The detection means 36 and the mechanical arm 38 are situated very close to each other, and the electronic indication means 36 are able to communicate this position to an electronic control system. The wheel 34 can cooperate with means for detection of the angular position of the wheel 34. A small magnet can be placed at the wheel 34 or embedded in the outer surface of the wheel 34. Detection means 42 can be placed at the frame 26 for detecting a magnet 44.

Combined with the step motor 28, the angular position of the wheel 34 can be calculated in a computer system operating in or connected to the light assembly.

During operation the first step motor 12 is able to turn the frame 26 around the axis 22 and 24 to move the belt 18 and rotate the wheel 20, which rotates around the axis 22. This way the supplementary optical component 10 can be moved from an operational position into a non-operational position. Furthermore, by means of the wheel 30 and the belt 32 the second step motor 28 can turn the supplementary optical component 10 and if appropriate let it rotate. If e.g. the supplementary optical component 10 is a beam shaper, it is necessary to adjust this beam shaper into optimum position during light performance. Instead, the supplementary optical element can be a prism or a beam splitter, where this prism or beam splitter can rotate during operation by means of a step motor 28.