EP0453932A2 - Lens arrangement for signal lamp, free of image phantoms - Google Patents

Abstract

The invention describes a signal arrangement (1) having a lens arrangement (2) free of ghost images. The lens arrangement consists of a plurality of plano-convex lenses (19 to 21) arranged distributed over an exit surface thereof. The convex curved surfaces (22 to 24) of these lenses face the reflector (8), which emits a parallel light beam (16) and is assigned to a light source (3). The planar surfaces (25 to 27) of these lenses, which are aligned approximately perpendicular to the parallel light beam (16) face a viewer (29). Arranged distributed over the exit surface or exit plane of the lens arrangement (2) is a multiplicity of planar surfaces (25 to 27) of which each is respectively assigned a plano-convex lens (19 to 21, 37). The total area of the planar surfaces (25 to 27) is between 3% and 20%, preferably 7%, of a cross-sectional area of the parallel light beam (16) projected by the reflector (8) onto the curved surfaces (22 to 24). Each planar surface (25 to 27) has an areal dimension of between 7 mm<2> and 0.02 mm<2>, preferably 0.3 mm<2>. <IMAGE>

Description

The invention relates to a signal arrangement with a phantom image-free lens arrangement, as described in the preamble of claim 1.

A known signal arrangement - according to US Pat. No. 2,907,249 - has a lens arrangement consisting of a plurality of plano-convex lenses, the convex curvature surfaces of which are arranged area-wide on the side assigned to the light source. In the area of the optical axes of the plano-convex lenses, light passage openings are arranged on an end face facing the viewer, while the surface parts adjacent to these light passage openings are covered by an opaque reflecting layer. Although this known lens arrangement already achieves a certain degree of reduction in phantom imaging in the presence of extraneous light, the extent of the reduction is in many cases not sufficient for traffic signal systems.

In a further known lens arrangement - according to GB-PS 1 591 013, several plano-convex lenses are also arranged, with a flat front of the plano-convex lenses on the observer side being preceded by an opaque pane which is provided with light passage openings in the region of the optical axes of the plano-convex lenses. It is thereby achieved that an axially parallel light entering from a parallel light bundle emerges from the individual plano-convex lenses in a convergent manner to the respective light passage openings and emerges from the plano-convex lenses. With this configuration of the lens arrangement, too, phantom image freedom suitable for signal security devices is not achieved.

The present invention has for its object to provide a lens arrangement in which the amount of extraneous light that can enter the lens arrangement is considerably reduced and the proportion of extraneous light that has entered the lens arrangement and is reflected back in the direction of the viewer can be further reduced .

This object of the invention is achieved by the features specified in the characterizing part of claim 1. It is advantageous in this embodiment that the surprisingly simple-appearing knowledge of creating a large number of light exit points with an extremely small cross-section distributed over the lens arrangement enables such a large reduction in the entry area for the extraneous light in relation to the area of the lens arrangement without this the light energy coming from the light source is disadvantageously reduced. The corresponding design also ensures that the observer of such a lens arrangement can perceive a uniform full-surface signal image even from a small distance from the radiation surface of the lens arrangement.

Another advantageous embodiment is described in claim 2, whereby a concentric light exit cone is achieved with respect to the incoming parallel light beam.

Another development according to claim 3 ensures that a concentric spread of the incident parallel light beam is ensured.

It is advantageous in the embodiment variant according to claim 4 that the optical axes of the light bundles upon entry into the lens arrangement and upon exit from the lens arrangement are the same and thus the alignment of the light beam bundle is also possible by adjusting the entire signal device or a corresponding angular alignment.

By designing the plano-convex lens according to claim 5 Above all, a reduction in the radiation area for the light rays of extraneous light is achieved without additional measures.

Through the development according to claim 6, the cross-sectional area of the plano-convex lens through which light rays from the external light source can enter can additionally be reduced without adversely affecting the emitted light rays. If the opening angle of the truncated cone is still determined as a function of the marginal rays, it is possible to make the truncated cones as small as possible without the radiation of the light rays coming from the light source being impeded.

In the embodiment according to claim 7, it is advantageous that undesired refraction of the light rays emerging from the light source and also loss through absorption are reliably prevented.

An embodiment according to claim 8 enables in a simple manner that the light rays incident from the external light source, which lie outside the plane surfaces of the lens arrangement, are immediately absorbed and thus rendered harmless. In addition, however, those light rays of the external light source are also absorbed by this design, which have a reflection angle after passing through the plane surface, which is larger to the optical axis of the plane convex lens than half the opening angle of the truncated cones. It is also advantageous in this embodiment that a smooth surface of the lens arrangement can be created which does not require an additional protective pane and additionally prevents the depositing of dust or snow and ice.

However, an embodiment according to claim 9 is also possible, in which the length can often be found even without post-treatment of the flat surfaces.

In the embodiment according to claim 10, a simple manufacture of the lens arrangement from plastic materials with relatively low loss values when passing light is possible.

The embodiment according to claim 11 is also advantageous, since it achieves a uniform refraction of light of the light rays entering the lens arrangement and thus a uniform fanning out of the same when it exits the lens arrangement.

Due to the design according to claim 12, the emerging light bundle can be composed of a large number of identical individual light bundles.

A preferred further development according to claim 13 is particularly advantageous in traffic signal systems in which the same luminance is to be achieved in the planes parallel to the roadway on both sides of the signal device, while in the planes running vertically to the roadway the luminance is primarily between the signal arrangement and the roadway should be particularly intense. This is achieved by a one-sided expansion of the spherical cap or the spherical cap section from the optical axis in the direction facing away from the carriageway, since as a result the light bundles emerging from the lens arrangement 2 are generally inclined in the direction of the carriageway without an additional lens arrangement and thus one further refraction is necessary, as a result of which the light losses in an inventive lens arrangement can be kept extremely low.

Due to the configuration according to claim 14, any light intensity variation in the emitted light beam can be easily achieved and the lens arrangement according to the invention can therefore be easily adapted to and used for a wide variety of applications.

A further development according to claim 15 is also advantageous for changing the luminous image.

Due to the configuration according to claim 16, the luminance in the overall light beam emitted by the lens arrangement can be varied in a simple manner. However, further training according to claim 17 is also advantageous.

Above all, a very simple manufacture of the tools for the production of a lens arrangement according to the invention is achieved by the features according to claim 18. It is therefore only necessary to create a tool for a lens group and to produce a sufficient number of such lens groups for the lens arrangement to be produced, which can then be combined by gluing them together to form the desired lens arrangements. By removing a negative form, e.g. The two surfaces of a lens arrangement to be designed according to the invention can be produced by electrochemical processes and can then form the surfaces in the injection molds and the like.

The embodiment according to claim 18 allows a diverse application of the lens arrangement according to the invention.

Through the development according to claim 20, the subsequent cross section of the truncated cones or the flat surfaces of the lens arrangement can be reduced to the computational minimum without different light losses occurring under changing operating conditions.

The further design variants according to patent claims 21 and 22 enable any spatial orientation of the emitted light beam in the desired spatial direction.

An embodiment variant according to claim 23 enables the creation of additional light beams that can be emitted in different directions from the main light beams, for example to be able to read the signal image perfectly even at a location directly in front of the signal arrangement, without the reading being adversely affected from long distances or the arrangement of a further signal device is necessary to determine the signal state up close.

Finally, a further development according to claim 24 is also possible, whereby the planar surfaces for the exit of the light rays from the light source after the lens arrangement has been completed, for example, by the light rays passing through can be made translucent themselves.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawings.

Fig. 1

eine Verkehrsampel mit erfindungsgemäß ausgebildeter Linsenanordnungen in Seitenansicht und vereinfachter schematischer Darstellung;

Fig. 2

eine Signalanordnung der Verkehrsampel in Seitenansicht und im Schnitt gemäß den Linien II-II in Fig. 1 und in vergrößertem Maßstab;

Fig. 3

einen Teil der Linsenanordnung nach Fig.2 in Stirnansicht gemäß Pfeil III in Fig.2;

Fig. 4

die Linsenanordnung nach Fig.3 in Draufsicht, geschnitten gemäß den Linien IV-IV in Fig.3;

Fig. 5

die Linsenanordnung in Seitenansicht, geschnitten gemäß den Linien V-V in Fig.3 und mit in schematischen Linien eingezeichneten, von der Lichtquelle kommenden Lichtstrahlen;

Fig. 6

die Seitenansicht der Linsenanordnung nach Fig.5, jedoch mit den schematisch das einfallende Licht darstellenden Lichtstrahlen einer Fremdlichtquelle;

Fig. 7

den Strahlenverlauf in einer Plankonvexlinse der erfindungsgemäßen Linsenanordnung;

Fig. 8

einen Teil einer anderen erfindungsgemäß ausgebildeten Linsenanordnung in Stirnansicht;

Fig. 9

die erfindungsgemäße Linsenanordnung in Draufsicht, geschnitten gemäß den Linien IX-IX in Fig.8;

Fig. 10

eine Lichtsignalanordnung mit einer weiteren erfindungsgemäß ausgebildeten Linsenanordnung in Stirnansicht;

Fig. 11

die Signalanordnung nach Fig.10 in Seitenansicht;

Fig. 12

ein Schemabild der Leuchtdichteverteilung des aus der erfindungsgemäßen Linsenanordnung austretenden Strahlenbündels.

Show it:

Fig. 1

a traffic light with inventive lens arrangements in side view and simplified schematic representation;

Fig. 2

a signal arrangement of the traffic lights in side view and in section along the lines II-II in Figure 1 and on an enlarged scale.

Fig. 3

part of the lens arrangement of Figure 2 in front view according to arrow III in Figure 2;

Fig. 4

the lens arrangement of Figure 3 in plan view, cut along the lines IV-IV in Figure 3;

Fig. 5

the lens arrangement in side view, sectioned along the lines VV in Figure 3 and with drawn in schematic lines, coming from the light source light rays;

Fig. 6

the side view of the lens arrangement according to Figure 5, but with the schematically representing the incident light rays of an external light source;

Fig. 7

the beam path in a plano-convex lens of the lens arrangement according to the invention;

Fig. 8

a part of another inventive lens arrangement in front view;

Fig. 9

the lens arrangement according to the invention in plan view, cut along the lines IX-IX in Figure 8;

Fig. 10

a light signal arrangement with a further lens arrangement designed according to the invention in front view;

Fig. 11

the signal arrangement of Figure 10 in side view;

Fig. 12

a schematic image of the luminance distribution of the beam emerging from the lens arrangement according to the invention.

1 shows a signal arrangement 1, in the present case a traffic light. In this traffic light, the various directions of travel are assigned, according to the invention, phantom image-free lens arrangements 2 are arranged. In the present exemplary embodiment, the bottom lens arrangement 2, which usually shows green light, is illuminated by a light source 3 and emits a beam 5, indicated schematically by rays 4, in the direction of an observer.

Problems now arise from the fact that extraneous light influences occur. This is, for example, in the area of a known lens arrangement which shows red light in a conventional manner. In the present case in particular, light rays 6 from an external light source, for example the sun 7, indicated by dash-dotted lines, are incident through them in known lens arrangements. If corresponding precautions are now not taken, the light rays 6 of the external light source, for example sun 7, can pass through the lens arrangement 2 and strike a reflector 8 arranged in the region of the light source 3. If these light beams 6 are reflected by the reflector 8, they emerge as dash-dotted light beams 9 from the lens arrangement in the direction of the viewer. If, for example, a vehicle approaches the signal arrangement 1 from a greater distance, it is usually not possible for the driver to see whether red or green light is now switched on. This leads to an indifferent traffic situation, since it is not evident whether passage or passing the signal arrangement 1 is permitted or not.

2 shows a lens arrangement 2 according to the invention and the light source 3 assigned to it and the reflector 8. As can be seen from this illustration, light filaments 12 to 14 emanate from a filament 10 which is arranged in a focal point 11 of the reflector 8 and are differently numbered for better understanding of the refraction conditions and the light beam path in the lens arrangement 2. These light beams 12 to 14 are reflected by the reflector 8 and aligned parallel to a longitudinal central axis 15 of the lens arrangement 2, so that they form a parallel light bundle 16 with a cross section corresponding to the luminous area of the lens arrangement 2. The parallel light beam 16 is, as indicated by thin arrows, directed against a light source-side surface of the lens arrangement 2, which consists of a plurality of plano-convex lenses 19 to 21 indicated by optical axes 17, 18, the convex curved surfaces 22 to 24 of which face the reflector 8 are. Flat surfaces 25 to 27 form an exit surface 28 of the lens arrangement 2, which face a viewer 29 - represented schematically by an eye. When the light rays of the parallel light bundle 16, in particular the light ray 14, pass through, these light rays 12 to 14 are deflected in the direction of the longitudinal central axis 15. The other light beams of the light bundle are emitted in all further spatial directions, depending on the configuration of the convex curvature surfaces 22 to 24. The lens arrangement 2 can also be preceded by a translucent, transparent protective cap 30, which can also be designed as a deflecting lens. This protective cap 30 is preferably provided with steps 31 so that it forms a step or Fresnel lens. It can thereby be achieved that the light rays 12 to 14 emerging from the lens arrangement 2 in the direction of the viewer 29 and all other light rays regardless of their exit direction by a certain angle 32, e.g. be deflected in the direction of a roadway 33.

3 to 6, part of the lens arrangement 2 according to the invention is shown on a larger scale. The convex curvature surfaces 22 and 24 are assigned to the flat surfaces 25, 27. These flat surfaces 25 are arranged together in an alternating sequence in a row 34 and at a distance 35 with flat surfaces 36, which a plano-convex lens 37 with a optical axis 38 are assigned. The light emerging from the light source 3 via a convex curved surface 39 emerges via the plane surface 36.

As can be seen from this illustration, the spherical cap sections are curved mirror-symmetrically to the optical axis 17 of the plano-convex lens 20 in the plan view. The same applies to the convex curved surfaces 24, but also to the convex curved surfaces 39, which, however, are arranged mirror-symmetrically to the optical axis 38 of the plano-convex lens 37. Likewise, the convex curvature surfaces 23 of the plano-convex lenses 19 are arranged mirror-symmetrically to their optical axis 18. The radiation course resulting from this mirror-symmetrical arrangement of the convex curvature surfaces 22, 23, 24, 39 will be explained in detail below.

The plano-convex lenses 19 of the lens arrangement 2 are arranged in a row 40 at a distance 41, the plane 42 receiving the optical axes 18 of these plano-convex lenses 19 being aligned parallel to the longitudinal central axis 15 of the lens arrangement 2.

In a plane 43 perpendicular to the plane 42, the plane surfaces 36 of the same type with their optical axes 38 in the direction of the row 44 are each arranged at the same distance 45 as the plane surfaces 26. However, the two rows formed by the plane surfaces 26 and 36 are offset in the longitudinal direction of the row 44 by less than half the distance 45 from one another.

Due to the different distances 35 and 41 and the arrangement of the plane surfaces 26 and 36, which is offset by less than half a distance 45, the two in each case half rows 40 and one row 34, as well as a vertical row 44 and half a row 46 arranged on both sides of the row 44, and in each case in a row 47, 48 arranged on both sides of the row 44, a lens group 49 is formed, which is schematically delimited in FIG. 3 by a dash-dotted line.

Several arranged one above the other in the direction of the vertical plane 43 Lens groups form a lens block 50, the lens arrangement 2 according to the invention being composed of a plurality of lens blocks 50 arranged next to one another.

It can be seen from the illustration in FIG. 5 that in the present exemplary embodiment the convex curvature surfaces 22 to 24 and 39 are not arranged mirror-symmetrically to the optical axes 17, 18 and 38 of the plano-convex lenses 19 to 21 and 37. Rather, the spherical cap sections extend in the vertical plane 43 by a variable angle 51 to 54 in the same direction with respect to the optical axis 17 or 18 or 38.

This eccentric arrangement of the convex curvature surfaces 22 to 24 and 39 has the effect that the light rays 14 emerging from the plane surface 25 to 27 and 36 of the parallel light bundle 16 move with increasing distance from the plane surfaces 25 to 27 and 36 in the direction opposite the convex curvature surfaces remove from the optical axis 17 or 18 or 38. This arrangement of the convex curved surfaces 22 to 24 and 39 therefore makes it possible to align the light beams 55 emerging from the plano-convex lenses 19 to 21 and 37.

In FIG. 4 it is also shown with thin lines that a truncated cone 57 projecting over part of a thickness 56 and between them flat end faces 58 are provided with an opaque coating 59. Furthermore, it is shown in this illustration that a light beam 6 incident from an external light source, for example the sun 7, can only fall into the plano-convex lens 19 to 21 and 37 up to a maximum angle 60 to the optical axis 17 or 18. With the maximum angle 60 becoming smaller with respect to the optical axis 17, 18, the proportion of the rays that can enter the plano-convex lenses 19 to 21 and 37 becomes higher. Overall, however, the proportion of those light rays 6 of the extraneous light that can enter the plano-convex lenses 19 to 21 and 37 is very small, since the opaque coating 59 blocks a large part of the surfaces for the rays of light 6 from entering. Moreover, the coating 59 also removes those rays that eg in the area of the truncated cones 57 could still enter the plano-convex lenses 19 to 21 and 37, likewise absorbed.

As the illustration shows the course of the light beam 6 coming from the external light source, it strikes the convex curved surface 24 of the adjacent plano-convex lens 20 after passing through the plano-convex lens and emerges at an angle 61 in the direction of the reflector 8. Due to the refraction that the light beam 6 experiences in the transition from the convex curvature surface 24 into the air, it is thrown in any direction onto the reflector 8, which reflects it at an arbitrary angle until its energy is reduced. Only for that special case in which, due to the different refractive laws and the maximum angle 60 corresponding to the angle of incidence, the light beam 6 of the extraneous light would pass exactly through the focal point of the reflector 8 would the light beam be reflected such that it passes through one of the plane surfaces 19 to 21 and 37 could leave the lens arrangement 2 in the direction of the viewer 29. Thus, the maximum possible amount of external light that can enter the lens arrangement 2 due to the ratio of the total area of the plane surfaces 25 to 27 and 36 in relation to the total cross-sectional area of the parallel light bundle 16, which in the embodiment variant described is, for example, 7%, throttled to a percentage of 10% to 15%, i.e. 0.7% to 1% of the parallel light beam. As a result, no phantom light exit from the lens arrangement 2 can be determined for an observer 29 even in the event of extremely unfavorable incidence of extraneous light.

6 shows the same section through the vertical plane 43 through the lens arrangement 2, as is shown in FIG. With the aid of this representation, however, the course of the reflection of the light beam 6 coming from an external light source, for example the sun 7, whose course has already been roughly described with reference to the refraction in the horizontal plane, will now be explained in more detail.

If, for example, such a light beam 6 strikes the plane surface 27 at an angle 62 with respect to the optical axis 17, then it becomes in the direction of the optical axis 17 in accordance with the laws of refraction redirected. He now passes through the lens arrangement 2 in such a way that it strikes in the region of the convex curvature surface 22 of the adjacent plano-convex lens 21. According to the laws of refraction, when the light beam emerges from the plano-convex lens 21, the light beam 6 is corresponding to the refractive index by a perpendicular 64 perpendicular to the tangent at the intersection with the tangent at the point of intersection with the convex curvature surface 22 by a larger angle in by the refractive index the direction opposite to the entry angle 63 is broken. After the focal point 11 is not passed through by this light beam 6, it is reflected by the reflector 8 in any direction. If such a light beam 6 reflected by the reflector 8 again strikes a convex curvature surface 22 to 24 or 39, then this occurs at a larger divergence angle than, for example, 2 ^o relative to the parallel light, it is reflected in a region of the lens arrangement 2 , which is provided with an opaque coating 59 and is absorbed by this.

7 shows a plano-convex lens 19 on a larger scale. The light rays 14 incident from the parallel light bundle 16 are deflected in the plane 42 in accordance with the laws described below.

The deflection is described using an edge ray 65 of the parallel light beam 16. The edge ray 65 is deflected by an angle 66 in the direction of the optical axis 18 when it hits the convex curvature surface 23. This angle 66 is calculated from an angle 67 between the optical axis 18 and a surface normal 68 intersecting the point of incidence of the marginal ray 65 on the convex curvature surface 23.

An angle 69 between the surface normal 68 and the deflected edge ray 65 is the arc sine of the sine from the angle 67 divided by the refractive indices of the plano-convex lens 19. The angle 66 is the difference between the angles 67 and 69.

An exit angle 70 is then calculated from the arc sine of the product from the sine of the angle 66 and the refractive index of the plano-convex lens 19. Starting from the marginal rays 65 assigned to the plano-convex lens 19, the result is in the plane 42 at the outlet at the plane surface 26 with a diameter 71 an approximately conical light beam with an opening angle that corresponds to the double exit angle 70.

Through the intersection of the edge rays 65 with the plane surface 26, the diameter 71 of the plane surface 26 is determined at the same time. Due to the opening errors that occur with such plano-convex lenses, which are also called spherical aberration, since the edge beam 65, which has a greatest penetration height 72 with respect to the optical axis 18, has the smallest focal length 73 with respect to a center 74 of a radius 75 that defines the convex curvature surface 22 to 24 forming spherical cap section.

The marginal rays 65 thus have the largest diameter 71 of the scattering circle with respect to the plane surface 26. The exit plane 76 receiving the plane surface 26 is located in the region of the spherical longitudinal aberration 77. This spherical longitudinal aberration depends on the shape of the plano-convex lens or its deflection, on the refractive index and on the position of the thing point on the optical axis 18 of a plano-convex lens delimited by a spherical surface .

The spherical longitudinal aberration 77 increases with increasing puncture height 72. If the penetration height 72 of the marginal rays 65 is designed such that their angle 66 to the optical axis 18 does not yet differ significantly from the angles of the light rays 14 lying therebetween, the double angle 66 can at the same time form an opening angle 78 of the truncated cone forming the end region of the plano-convex lens 19 57 form. In this case, the flat surface 26 is positioned so that the diameter 71 of the scattering circle of the marginal rays 65 corresponds to the diameter of the flat surface 26.

With a symmetrical arrangement of the convex curvature surfaces 22 to 24 to the optical axis 17, the parallel light beam 16 striking the convex curvature surfaces 22, 24 is thus converted into a radiated conical light beam 79 defined by the double angle 70.

If light beam 6 of the external light coming from an extraneous light source, for example the sun 7, enters a plane convex lens 19, as indicated by thin dash-dotted arrows, on the exit plane 76, it can be seen from this illustration that a large part of the light rays 6 of the extraneous light the opaque coating 59 hits the outer surface of the truncated cone 57 or the end faces 58 between these individual truncated cones and is absorbed there.

Only a small part of the light rays can pass through the plane surface 26 at all, such as the light beam 80. According to the law of refraction, the light beam 80 passing from the denser medium into the less dense medium becomes the one passing through the intersection between the light beam 80 and the convex curvature surface 23 Surface normals 68 are broken away from the so-called plumb so that the light beam 80 emerges from the convex curvature surface almost at an angle of 90 ^° to the light beams 14 or edge beams 65 of the parallel light bundle 16.

This then strikes a tube 81 - FIG. 2 - which closes the free space between the reflector 8 and the lens arrangement 2 and is provided on its inside with a light-absorbing coating 59. As a result, the beam is absorbed and can no longer form irritations for the viewer 29. Only that small proportion of the light rays 6 or 80 coming from extraneous light, which exactly passes through the focal point 11, ie the filament 10 of the light source 3 formed by a lamp, could be deflected by the reflector 8 in such a way that it is parallel or with such a small divergence to the longitudinal central axis 15 of the lens arrangement 2 that it can exit through the flat surface 26 of the plano-convex lens 19 again in the direction of the viewer 29.

However, since the sum of the areas of the plane surfaces 25 to 27 and 36 of the entire lens arrangement 2 available for the passage of light is only approximately 7% of the cross-sectional area of the parallel light bundle 16 and, moreover, those light rays 6 and / or those through the convex curvature surfaces 22 to 24 and 39 80 of the extraneous light, which can still enter the lens arrangement 2 through these plane surfaces 24 to 26 and 38, are deflected in a wide variety of spatial directions so that they do not pass through the focal point 11 of the reflector 8, even with an ideal angle of incidence of the light rays 6 and 80 of the extraneous light have no phantom image on the lens arrangement 2. This results from the fact that, for example, the diameter 71 of the flat surfaces 26 is only between 0.2 mm and 3 mm, preferably 0.6 mm.

The elimination of the phantom image effect is also supported above all by the fact that part of the plano-convex lenses 19 to 21 and 37 is formed by the truncated cone 57 or an exit cone, since light rays 6 and 80 of the extraneous light, which are at a larger angle, based on the optical axes 17, 18 and 38 are incident as half of the opening angle 78, already in the area of this truncated cone 57 impinge on its outer surface and thus on the opaque coating 59 and are absorbed by the latter.

8 and 9 show an embodiment variant of a lens arrangement 2 in which the plano-convex lenses 19 have a convex curved surface 23 which forms a spherical cap section which is mirror-symmetrical to the optical axis 18 both with respect to the plane 42 and the vertical plane 43 runs. Accordingly, a section through the plane 42 corresponds to a section through the vertical plane 43, as shown in FIG.

A light bundle 79 emitted by such a lens arrangement 2 thus corresponds to a cylindrical cone, so that the same light emission is produced over the entire exit plane 76 of the lens arrangement 2, the optical axes of the emitted light bundles 79 parallel to the light beams 14 or edge beams 65 of the parallel light bundle 16 run.

From this comparison of the embodiment variant in FIGS. 8 and 9 with the embodiment variant described in FIGS. 2 to 7, it can be seen that by appropriately designing the convex curvature surfaces 22 to 24 and 39, both the radiation conditions and the luminance of the emitted light beams are within wide limits can be varied without losing the advantages of phantom image suppression essential to the invention, as long as the size of the plane surfaces corresponds to the values described above.

10 and 11 show on the basis of a signal arrangement 1 for rail traffic that it can be achieved by using individual plano-convex lenses, which can be distributed over the surface of the lens arrangement 2, or by inserting a lens group 49 or a lens block 50 in the lens arrangement 2 is possible to emit at least one partial light bundle 82 in a direction spatially offset from the main light bundle 83. This effect is required above all if the signal arrangement 1 is already set up to display the signal image over long distances and the signal image is also to be read from a short distance from the signal arrangement, for example from the driver's cab of a locomotive. If a lens group or a lens block is arranged within the lens arrangement, the light rays of which entirely form the partial light bundle 82, this can possibly result in the signal image not appearing over the entire surface. If, on the other hand, only one or two plano-convex lenses are arranged in each lens group, which deflect some light rays in the direction of the partial light beam 82, a reduction or influence on the main light beam 83 can usually not be determined at all.

Instead of the opaque coating 59, it is also possible, in order to reduce the amount of light rays from the external light source which can enter the lens arrangement 2, to cover the region between the truncated cones 57 to the region of the end faces 58 with an opaque material 84, such as this is indicated schematically in Figure 9 - to fill. Through this opaque or light-absorbing material 84 a light can actually only enter through the plane surfaces 26, or rays that have a larger entrance angle than half the opening angle of the truncated cone 57 are also absorbed by this material 84. At the same time, however, light rays of extraneous light, for example, which impinge on the reflector in any spatial direction and are directed back in the direction of the lens arrangement 2, are prevented from emerging from the lens arrangement 2 if they do not actually pass through the truncated cones 57.

Of course, instead of truncated cones 57, truncated pyramids or other geometrical bodies can also be used. You only have to ensure that all of the light rays incident on the curved surfaces 22 to 24 and 39 can exit through the plane surface 26. In order to prevent unwanted reflections in the area of the opaque material or the flat surfaces 26, it is advantageous if after the application of the material 84 the exit surface 28 of the lens arrangement 2 is ground flat, so that there is also a between the outer surface and the flat surface 26 of the truncated cone 57 sharp edge arises, which eliminates unwanted scattering of the light rays coming from the light source.

The individual beam paths or refraction angles and the resulting thickness ratios of the lens arrangement 2 or the radii of the curvature surfaces and the diameter of the plane surfaces can be calculated as desired in accordance with the optical laws.

An embodiment in which the radius of the convex curvature surfaces is 3.5 mm and the thickness of the lens arrangement from the curvature surface to the plane surface is 8.645 mm has proven particularly useful for use in traffic signal systems. A length of the truncated cones is preferably 2 mm and an opening angle 25 ^o ,

Of course, however, any other values are possible with the composition of the convex curvature surfaces corresponding to the light exit angle from the lens arrangement 2.

FIG. 12 shows schematically for the embodiment of the lens arrangement 2 according to the invention shown in FIGS. 2 to 7 that the luminous distribution in the emitted beam 5 or in the main light beam 83 is shown.

If the beam 5 emerging from the lens arrangement 2 is projected directly onto a surface arranged in front of the latter perpendicular to the longitudinal central axis 15, an area 85 with a high luminance results in connection with a plane 42 passing through the longitudinal central axis 15 in the direction of a roadway 33 an area 86 with medium luminance and an area 87 with low luminance adjoins at a greater distance from plane 42 in the direction of roadway 33. The areas with medium and low luminance have a greater width 88 and 89 with respect to the area 85 with high luminance.

This luminance distribution results from the fact that all those light rays striking the curved surfaces 22, 24 and 39 are concentrated in the region 85, the regions 86 and 87 also being irradiated by the curved surfaces 22 due to the larger angular opening of the curved surfaces 22 relative to the curved surfaces 24 and 39 will. While in region 87 only the light rays arriving from the curved surfaces 22 or from their side region strike, in the central region 86 the luminance is additionally increased by the irradiation of those light rays that impinge on the parallel light bundle 16 via the curved surfaces 23 or emerge from the lens arrangement 2 through the flat surfaces 25 to 27 or 36.

As already emphasized above, this luminance distribution is only a preferred exemplary embodiment and can be modified as desired according to the respective requirements by appropriately designing the curved surfaces and arranging them over the lens arrangement 2.

Just for the sake of order, it should be noted at this point that, for a better description of the solution according to the invention, the individual angles or size relationships have been greatly distorted and not shown to scale. Furthermore, all of the features disclosed in the description can form independent groups of features that are essential to the invention, and the combinations of features set out in the subclaims are particularly suitable for achieving independent, objective protection.

Reference numbering

1

Signal arrangement

2nd

Lens arrangement

3rd

Light source

4th

beam

5

Bundle of rays

6

Beam of light

7

Sun

8th

reflector

9

Beam of light

10th

Filament

11

Focus

12

Beam of light

13

Beam of light

14

Beam of light

15

Longitudinal central axis

16

Parallel light beam

17th

optical axis

18th

optical axis

19th

Plano-convex lens

20th

Plano-convex lens

21

Plano-convex lens

22

convex curvature surface

23

convex curvature surface

24th

convex curvature surface

25th

Flat area

26

Flat area

27th

Flat area

28

Exit surface

29

Viewer

30th

protective cap

31

step

32

angle

33

roadway

34

line

35

distance

36

Flat area

37

Plano-convex lens

38

optical axis

39

convex curvature surface

40

line

41

distance

42

level

43

vertical plane

44

line

45

distance

46

line

47

line

48

line

49

Lens group

50

Lens block

51

angle

52

angle

53

angle

54

angle

55

Beam of light

56

thickness

57

Truncated cone

58

Face

59

Coating

60

Maximum angle

61

angle

62

angle

63

Entry angle

64

Plumb

65

Edge jet

66

angle

67

angle

68

Surface normal

69

angle

70

Exit angle

71

diameter

72

Puncture height

73

Focal length

74

Focus

75

radius

76

Exit level

77

Longitudinal aberration

78

Opening angle

79

Beam of light

80

Beam of light

81

Tube

82

Partial light beam

83

Main light beam

84

material

85

Area

86

Area

87

Area

88

width

89

width

Claims (24)

Signal arrangement with a phantom-image-free lens arrangement consisting of a plurality of plano-convex lenses distributed over an exit surface thereof, the convex curvature surfaces of which face the reflector which emits a parallel light beam and are assigned to a light source and whose plane surfaces are oriented approximately perpendicular to the parallel light beam and face an observer characterized in that a plurality of plane surfaces (25 to 27, 36) is arranged distributed over the exit surface or plane of the lens arrangement, each of which is assigned to a plane convex lens (19 to 21, 37) and the total area of the plane surfaces (25 to 27.36) is between 3% and 20%, preferably 7%, of a cross-sectional area of the parallel light beam (16) projected by the reflector onto the curved surfaces (22 to 24.39) and that each plane surface (25 to 27.36) is one Surface area between 7 mm² and 0.02 mm², preferably 0.3 mm². Signal arrangement according to Claim 1, characterized in that a center point of the convex curvature surfaces (22 to 24.39) is arranged on an optical axis (17, 18, 38) of the plano-convex lens (19 to 21, 37). Signal arrangement according to claim 1 or 2, characterized in that the plane surface (25 to 27.36) is arranged concentrically to the optical axis (17, 18, 38) of the plane convex lens (19 to 21, 37). Signal arrangement according to one or more of Claims 1 to 3, characterized in that the optical axis (17, 18, 38) of the plano-convex lens (19 to 21, 37) is approximately parallel to the light beams (12 to 14) of the parallel light beam ( 16) is aligned. Signal arrangement according to one or more of claims 1 to 4, characterized in that the plano-convex lens (19 to 21.37) extends from the curved surface (22 to 24.39) into the region of the Signal arrangement according to one or more of claims 1 to 5, characterized in that the plane-convex lens (19 to 21.37) at least over part of its thickness from the plane surface (25 to 27.36) in the direction of the curved surface (22 to 24.39 ) which widens conically, in particular as a truncated cone (57), and preferably defines an opening angle of the truncated cone (57), starting from the edge rays (65) having the greatest penetration height (72) from the optical axis (17, 18, 38) is. Signal arrangement according to one or more of claims 1 to 6, characterized in that the diameter (71) of the flat surface (25 to 27.36) corresponds to the maximum scattering circle diameter in the exit plane which receives the flat surface and preferably between 0.2 mm and 3 mm, preferably 0.6 mm. Signal arrangement according to one or more of Claims 1 to 7, characterized in that the cavities between the truncated cones (57) in the exit plane (76) are filled with an opaque material (84). Signal arrangement according to one or more of Claims 1 to 8, characterized in that an outer surface of the truncated cones (57) and the end faces (58) of the lens arrangement (2) arranged between them are provided with an opaque coating (59). Signal arrangement according to one or more of Claims 1 to 9, characterized in that the plano-convex lenses (19 to 21, 37) of the lens arrangement (2) form an integral component. Signal arrangement according to one or more of claims 1 to 10, characterized in that the curved surface (22 to 24, 39) is formed by a spherical cap section. Signal arrangement according to one or more of Claims 1 to 11, characterized in that the radius (75) of the spherical cap sections of all plano-convex lenses (19 to 21, 37) is of the same size. Signal arrangement according to one or more of claims 1 to 12, characterized in that the spherical cap section is formed at least in one plane (42) symmetrically to the optical axis (17, 18, 38) of the plano-convex lens (19 to 21, 37) and preferably is in a plane (43) essentially perpendicular thereto, starting from the optical axis (17, 18, 38) of the plano-convex lens (19 to 21, 37), extends only in one direction over an angle between 20 ^° and 45 ^° . Signal arrangement according to one or more of Claims 1 to 13, characterized in that the convex curvature surfaces (22 to 24, 39) of the plano-convex lenses (19 to 21, 37) arranged in rows (34, 40) parallel to the plane (42) each differ Have opening angles in this plane (42). Signal arrangement according to one or more of Claims 1 to 14, characterized in that the curvature surfaces (22 to 24, 39) of the plano-convex lenses (19 to 21, 37) arranged in different rows (34, 40) differ in the vertical plane (43) Have opening angles. Signal arrangement according to one or more of claims 1 to 15, characterized in that the distances (35, 41) between the planar surfaces (25 to 27, 36) arranged in the rows (34, 40) running parallel to the plane (42) or of the optical axes (17, 18, 38) assigned to these flat surfaces are of different sizes. Signal arrangement according to one or more of Claims 1 to 16, characterized in that the plane surfaces (25 to 27.36) or the optical surfaces assigned to them are arranged in rows (44, 46 to 48) running parallel to one another and to the vertical plane (43) Axes (17, 18, 38) of the plano-convex lenses (19 to 21, 37) are arranged at different distances (45) from one another. Signal arrangement according to one or more of Claims 1 to 17, characterized in that a plurality of plane-convex lenses (19 to 21, 37) arranged in at least two rows (34, 40) parallel to the plane (42) form a lens group (49) and the lens arrangement (2) is formed from a plurality of lens blocks (50) which are arranged next to one another and each consist of lens groups (49) arranged congruently one above the other. Signal arrangement according to one or more of claims 1 to 18, characterized in that the emission characteristic of a lens group (49) corresponds to the emission characteristic of the lens arrangement (2). Signal arrangement according to one or more of claims 1 to 19, characterized in that the divergence of the light beams (12 to 14) in the parallel light beam (16) is between +/- 0 ^o and +/- 3 ^o , preferably +/- 2 ^o , is. Signal arrangement according to one or more of claims 1 to 20, characterized in that the divergence angle of the emitted light beam (79) is aligned symmetrically to the optical axis (17, 18, 38) of the plano-convex lens (19 to 21, 37). Signal arrangement according to one or more of claims 1 to 21, characterized in that the divergence angle of the emitted light beam (79) in a plane parallel to the vertical plane (43) asymmetrical to the optical axis (17, 18, 38) of each plano-convex lens (19 to 21 , 37) runs. Signal arrangement according to one or more of claims 1 to 22, characterized in that the divergence angles of the individual plano-convex lenses (19 to 21, 37) and / or the lens blocks (50) and / or lens groups (49) are different. Signal arrangement according to one or more of claims 1 to 23, characterized in that the flat surfaces (25 to 27.36) are formed by translucent parts of a flat end face or by recesses in an opaque layer.

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