GB2129535A - Searchlight - Google Patents

Abstract

In order to uniformly illuminate a floodlit target to the required light distribution, the inner area of a searchlight casing contains a plurality of lamps, with different illumination characteristics, arranged on a lamp bracket held in rotary manner in the optical axis of the main concave mirror and individually pivotable into the focus of said main concave mirror.

Description

SPECIFICATION Searchlight The invention relates to a searchlight comprising a casing, a main concave mirror, several auxiliary concave mirrors and several lamps as radiation sources.

On the basis of known or realisable optical laws, it is necessary for producing a required searchlight light distribution in the light beam or in the floodlit target, on the basis of the optimum overall efficiency, that the main elements participating in beam focusing, namely the searchlight main concave mirror, preferably a parabolic mirror, the lamp constituting the radiation source necessary for energy conversion and the auxiliary concave mirrors necessary for efficiency optimization are matched to one another in an optimum manner from the optical and illumination standpoints.On the basis of a main concave mirror with a given focal length and diameter, a lamp with given dimensions of the elements participating in the emission and for the optimization of the efficiency of the auxiliary concave mirror adapted thereto, there is a given light distribution in the light beam emitted by the searchlight. This light distribution is determined by the focal length of the main concave mirror and the dimensions of the lamp elements participating in the emission. These are not variable in the once fixed mirror lamp combination and consequently determine the light distribution.

Known methods, such as e.g. light distribution by defocusing the lamp, i.e. moving the light-emitting lamp part out of the mirror focus, are only successful to a limited extent, because as a result, the system elements are no longer matched to one another. This is particularly the case if a very strongly focused light beam is to be changed to a widely scattered light beam. Apart from the efficiency loss, this leads to a light intensity burst in the centre of the beam, so that the target is no longer illuminated in an optimum manner, i.e. uniformly.

The problem of the invention is therefore to provide a searchlight in which the searchlight main concave mirror, the lamp necessary for energy conversion and the auxiliary concave mirrors necessary for efficiency optimization are matched to one another optically and from the illumination standpoint in such a way that in the case of a light distribution adaptable to the particular use and variable in optimum manner, by varying the dimensions of the elements participating in light emission, the floodlit target is illuminated in an optimum manner, i.e. uniformly.

According to the invention, this problem is solved by a searchlight of the aforementioned type which, according to the invention, is constructed so that in the inner area of the searchlight casing and in front of the main concave mirror is arranged a support with a circular disk-like lamp bracket rotatable by hand or by motor about a rotation axis at right angles to the optical axis of the searchlight and which has a plurality of lamps with different illumination characteristics, which can be individually pivoted into the focus of the main concave mirror and fixed therein and which are adapted to these lighting conditions as a function of the light distribution of the searchlight.

In the case of a searchlight constructed in this way, in which the main concave mirror and several lamps has radiation sources, which can be brought into the focus of the main concave mirror as required, are combined with one another, the disadvantages occurring with conventional searchlights are avoided. On requiring a light distribution adapted to the particular use and when assuming that the main concave mirror present in an apparatus is not variable, the light distribution can only be varied in an optimum manner if the dimensions of the elements participating in the light emission are varied and this is achieved in that lamps with different emission behaviours are pivoted into the focus of the main concave mirror, as a function of the desired light distribution.

Further advantageous developments of the invention can be gathered from the subclaims.

The invention is described in greater detail hereinafter relative to the drawings, wherein show: Figure 1 a searchlight, partly in elevation and partly in vertical section.

Figure 2 a front view of the searchlight.

Figures 3 and 4 lamps with different filaments.

Figure 5 a lamp with a gas discharge arc of small size, but high luminance.

The searchlight 100 shown in Figures 1 and 2 comprises a casing 10, which is closed at the front by means of a sight glass 15 and a main concave mirror 20, constructed as a parabolic mirror and arranged in its inner area 11 adjacent to the rear wall 12 of the casing. The optical axis of the main concave mirror 20 is indicated at 21 and its focus at 22 in Figure 1.

A support 30 is arranged in front of the main concave mirror 20 in the inner area 11 of searchlight casing 10. Support 30 carries a lamp bracket 21 rotatable about a rotation axis 32 at right angles to the optical axis 21 of the main concave mirror 20. In Figures 1 and 2, lamp bracket 21 is constructed as a circular disk-like body and on its circumference carries a plurality of lamps 33, 33a, 33b 33c as radiation sources. The arrangement of lamp bracket 31 with its lamps 33, 33a, 33b, 33c in front of the main concave mirror 20 of the searchlight is such that the lamps can be individually pivoted into the focus 22 of the main concave mirror 20. Preferably, the lamp bracket 31 is rotatably arranged on support 30 in the optical axis 31 of the main concave mirror 20.

Lamps 33, 33a, 33b, 33c can be constructed in the same or different ways. Thus, the possibility exists that the pivotable lamps can be so constructed as filament lamps or lamps working according to the gas discharge principle. The lamps pivotable into the focus 22 of main concave mirror 20 can also be constructed partly as filament lamps and partly as lamps functioning according to the gas discharge principle. However, it is important that lamp bracket 31 carries different lamps with varying radiation behaviours. By rotating lamp bracket 31 in optical axis 21 and engaging in the particular position ensuring a clearly defined location of the radiation elements of the lamp with respect to focus 22 of main concave mirror 20, it is possible to select the particular light distribution of the searchlight.For example, lamps with different filaments are used (Figures 3 and 4).

In the case of the lamp shown in Figures, it is a construction with a gas discharge arc having very small dimensions, but a very high luminance. By pivoting in a lamp in accordance with an embodiment of Figure 3, the target would be illuminated with a very wide, but not very high light beam, with a lamp according to Figure 4 with a very narrow, but very high light beam and with a lamp according to Figure 5 with a very narrow concentric light beam.

The production of the light distributions is brought about by optimum adaptation of the optical components with the best possible efficiency.

Lamps 33, 33a, 33b, 33c to be pivoted into focus 22 of main concave mirror 20 are provided with auxiliary concave mirrors 40 adapted to the light distribution conditions of the lamp. The lamp and auxiliary concave mirrors preferably constitute a plug-in unit, so that it is possible to replace the individual lamps with their auxiliary concave mirrors in lamp bracket 31.

The pivoting of the individual lamps 33, 33a, 33b, 33c into the focus 22 of the main concave mirror 20 takes place by rotating lamp bracket 31 by hand or by an electromotive drive 36. Drive 36 is connected by means of a drive shaft 37 with drive gearing 35.

Besides the manual pivoting in of the lamps outside the casing, remote control is possible by means of an electric remote control device 60 (Figure 1).

All the lamps 33, 33a, 33b, 33c, with their auxiliary concave mirrors 40 represent a solid angle supplement, permitting an optimum utilization by the light flux. The pivoting in of the particular lamp simultaneously leads to the switching in or over of the power supply required for the lamp. Thus, each lamp 33, 33a, 33b, 33c is connected to the power supply device 50 required for it.

Since with respect to the use of a searchlight, optionally different light distribution combinations and consequently different lamp combinations are desired, the complete lamp bracket 31 is constructed as a unit and can be interchanged with a unit having a different lamp combination. By means of corresponding electrical switching elements combined with their control functions in lamp bracket 31 or support 30 for bracket 31, on introducing into the focus of main concave mirror 20 the particular lamps are switched on or, when switched over, are switch doff.

Another embodiment permits a constant motordriven rotation of lamp bracket 31, accompanied by the simultaneous switching on of all lamps 33, 33a, 33b, 33c. If lamp bracket 31 is rotated at a speed which is above the time resolving power of the eye, an optimum light distribution with integrated, constantly changing width maxima and minima is obtained in the target, due to the energy integration of the lamp emissions caused by the integration capacity of the eye.

The invention is not limited to the embodiments described hereinbefore and represented in the drawings. Divergences in the arrangements, construction and association of lamp bracket 31 to the main concave mirror 20 also fall within the scope of the invention, as does a different number of lamps arranged on bracket 31. However, the overall arrangement must always be such that the individual lamps can be pivoted into the focus 21 of main concave mirror 20.

The particular advantage of using a lamp bracket which can be rotated into the optical axis of the main concave mirror is that said bracket can on the one hand carry a plurality of lamps with different illumination characteristics and on the other hand no components influencing the path of the beam of the main concave mirror are located therein.

Claims (11)

1. A searchlight comprising a casing, a main concave mirror, a plurality of auxiliary concave mirrors and a plurality of lamps as radiation sources, wherein in the inner area of the searchlight casing and in front of the main concave mirror is arranged a support with a circular disk-like lamp bracket rotatable by hand or by motor about a rotation axis at right angles to the optical axis of the searchlight and which has a plurality of lamps with different illumination characteristics, which can be individually pivoted into the focus of the main concave mirror and fixed therein and which are adapted to these lighting conditions as a function of the light distribution of the searchlight.

2. A searchlight according to Claim 1, wherein each of the pivotable lamps is provided with an auxiliary concave mirror adapted in each case to the light distribution conditions of the lamp.

3. A searchlight according to Claims 1 and 2, wherein the pivotable lamps are constructed as filament lamps.

4. A searchlight according to Claims 1 and 2, wherein the pivotable lamps are constructed as lamps working according to the gas discharge principle.

5. A searchlight according to Claims 1 and 2, wherein the pivotable lamps are constructed partially as filament lamps and partially as lamps functioning according to the gas discharge principle.

6. A searchlight according to Claims 1 to 5, wherein each lamp pivoted into the focus of the main concave mirror is connected to the voltage supply device necessary for it.

7. A searchlight according to Claims 1 to 6, wherein the lamp support is pivotable by means of a remote control device.

8. A searchlight according to Claims 1 to 7, wherein the individual lamps of the lamp bracket are constructed with their auxiliary concave mirrors as plug-in units detachably connected to the bracket.

9. A searchlight according to Claims 1 to 8, wherein the lamp bracket with its lamps is arranged in the support as an interchangeable unit.

10. A searchlight according to Claims 1 to 9, wherein the lamp bracket with the switched-on lamps is constructed so as to constantly rotate at a rotation speed above the time resolving power of the eye.

11. A searchlight substantially as hereinbefore described with reference to the accompanying drawings.