EP3167227B1 - Signal generator for a traffic light, and traffic light - Google Patents

Description

The invention relates to a signal generator for a traffic signal system. The invention further relates to a traffic signal system.

Known signal generator of a traffic signal system usually comprise a light-emitting diode (in English: light emitting diode, LED). In the known LED signal generators, an amount of the light that the LEDs emit is not accurately and reliably measured. In particular, extraneous light entering from outside is not suppressed. Therefore, it can not be determined exactly whether the amount of light that emits the signal is sufficient to meet the minimum requirements set by the standard.

The publication WO 2011/086027 A1 shows a light signal, in particular railway light signal, with at least one LED.

The publication WO 2006/099732 A1 shows a light-emitting device.

The publication EP 1 156 271 A1 shows a lighting system.

The publication EP 1 988 752 A1 shows a lighting device comprising an LED.

The publication WO 2013/178597 A1 shows a lighting device with semiconductor light sources and a common diffuser.

The publication DE 10 2011 076 123 A1 shows a light signal device and a method for determining the Pollution degree of a lens of a signal generator.

The publication DE 10 2012 209 131 A1 shows a lighting device with semiconductor light sources and a common diffuser.

The patent US 3,947,131 A shows a device for indicating a degree of contamination of a windshield.

The publication DE 10 2004 035 438 A1 shows a traffic signal.

The object underlying the invention can therefore be seen to provide an improved signal generator for a traffic signal system, which overcomes the known disadvantages and allows a more accurate and reliable measurement of the signal light.

The object underlying the invention can furthermore be seen in providing a corresponding traffic signal system.

These objects are achieved by means of the subject matter of the independent claims. Advantageous embodiments of the invention are the subject of each dependent subclaims.

• eine lichtemittierende Diode zum Emittieren eines Signallichts,
• einen Photodetektor und
• einen Lichtleiter zum Leiten eines Teils des emittierten Signallichts von der Diode zum Photodetektor, sodass
• der Photodetektor den weggeleiteten Teil des emittierten Signallichts messen kann.

In one aspect, there is provided a signal transmitter for a traffic signal system, comprising:

• a light emitting diode for emitting a signal light,
• a photodetector and
• a light guide for guiding a part of the emitted signal light from the diode to the photodetector, so that
• the photodetector can measure the diverted portion of the emitted signal light.

According to yet another aspect, a traffic signal system is provided which comprises the signal generator according to the invention.

In particular, the invention therefore includes the idea of directing a portion of the emitted signal light away from the diode toward a photodetector by means of a light guide. As a result, it is advantageously made possible that a location of the measurement by means of the photodetector can be selected flexibly, so that, for example, an installation location for the photodetector can be selected, to which only little or no extraneous light penetrates. In particular, it is thus advantageously made possible that the predominant part of light which arrives at the photodetector originates from the signal light of the light-emitting diode. This is because the optical fiber can be positioned so that as far as possible signal light from the diode is coupled, which is then coupled out at the photodetector. Thus, therefore, it can be advantageously reduced or even avoided a negative influence by means of extraneous light with respect to the measurement by the photodetector.

By means of the light guide, it is thus possible in an advantageous manner that a targeted part of the signal light of the diode can be passed to the photodetector. In particular, it is advantageously made possible by means of the optical waveguide that a part of the signal light can be guided bundled over the optical waveguide to the photodetector.

As a result, it is advantageously effected that a quantity of light which emits the diode can be determined very precisely and that light penetrating from the outside (extraneous light) does not cause any significant influence.

The light-emitting diode can also be abbreviated as LED below. "LED" stands for the English terms light emitting diode, ie light emitting diode.

In one embodiment, a plurality of light emitting diodes are provided. The statements made in connection with a light-emitting diode apply analogously to a plurality of light-emitting diodes and vice versa.

According to one embodiment, the traffic signal system comprises a plurality of signal transmitters. For example, the traffic signal system comprises a red, yellow and green signal generator. Red, yellow, green here refers to the color of the signal light, which is emitted by means of the corresponding diode.

According to one embodiment, the signal generator is designed to emit a plurality of signal colors, for example red, yellow and green. The signal generator thus has in particular a plurality of fields.

• Photodiode: ca. 0,16%/K
• Phototransistor: ca. 0,9%/K

In one embodiment, the photodetector is a photodiode or phototransistor. In particular, a photodiode may also be referred to as a monitor diode. A phototransistor usually has a much higher sensitivity than a photodiode, but this can be partially compensated by the larger area of the photodiode. In contrast, a photodiode generally has better linearity and a lower temperature response. Typical temperature coefficients are for example:

• Photodiode: approx. 0.16% / K
• Phototransistor: approx. 0.9% / K

It is provided that an optical element for an optical imaging of the signal light is provided in a beam path of the signal light, wherein the optical fiber is optically coupled to the optical element, so that the optical element transmitting signal light partially coupled into the optical fiber as the conductive part can be.

As a result, in particular, the technical advantage is achieved that efficiently both an optical image of the Signal light and at the same time a coupling of the conductive part can be effected in the light guide. The optical element is a lens. The lens is formed as a slip-on lens. This means that the lens is plugged or arranged on the carrier.

The optical element is a lens which is a clip-on lens.

In a further embodiment, the optical element is attached to the carrier and / or to the diode, for example by means of screws. The optical element is glued and / or attached, for example, to the carrier and / or to the diode. Additionally or alternatively, according to one embodiment, it is provided that the cover (see below) fixes or locks or secures the optical element. That is, the optical element is fixed or locked or fixed by means of the cover, preferably on the carrier and / or on the diode.

The optical element according to an embodiment has one or more through holes for fastening means, for example screws, so that thereby advantageously a corresponding attachment of the optical element to the carrier and / or to the diode is effected.

The light guide and the optical element are formed according to an embodiment as a common component. This means that the light guide and the optical element are integrally formed. For example, the common component is formed as an injection molded part. As a result of the integral design, the technical advantage in particular that a position of the optical waveguide relative to the optical element can already be determined precisely during production, so that subsequent assembly inaccuracies can be avoided.

According to one embodiment, two optical elements are provided, each of which leaves its own light guide respectively each optically coupled to the two optical elements. Here, too, an integral construction is preferably provided, so that the two optical elements and the two light guides are formed as a common component, for example as an injection-molded part. For example, the two optical fibers direct signal light to a common photodetector or to two separate photodetectors. Even with more than two light guides, the above-described integral construction, for example as an injection-molded part, is preferably provided.

In another embodiment it is provided that a second photodetector and a second optical waveguide are provided for guiding a further part of the emitted signal light from the diode to the second photodetector so that the second photodetector can measure the diverted further part of the emitted signal light.

In another embodiment, it is provided that a second optical waveguide is provided for conducting a further part of the emitted signal light from the diode to the photodetector, so that the photodetector can measure the deflected further part of the emitted signal light.

By the aforementioned embodiments comprising a second optical fiber, which leads either to the photodetector (which may be referred to as a first photodetector) or to a second photodetector, in particular the technical advantage is effected that an extraneous light component can be determined even more accurately. This is due, in particular, to the fact that an angle of incidence of extraneous light into the two light guides is different and, as a result, the amount of extraneous light which is fed or coupled into the respective light guide is different. As a further explanation, it is noted that if the maximum extraneous light is fed into an optical waveguide (optimum angle of incidence), this will be lower in the second optical waveguide, since the extraneous light will not be in the optimum Incident angle is incident. By comparing these two values (amount of extraneous light), a part of the ambient light can be eliminated (eliminated). Designs that are made in the context of a light guide, apply analogously to two or more light guides.

The idea according to the invention thus consists, in particular, in that different amounts of extraneous light are coupled into the two light guides, so that the two photodetectors or the one photodetector measure different signals. Thus, therefore, an extraneous light component can be calculated out in an advantageous manner. Overall, thereby an even more accurate determination of an extraneous light portion is effected in an advantageous manner. The two light guides are preferably the same or in particular formed differently. Even in the case of different light guides, it is possible to calculate out an extraneous light component, as described above, and according to one embodiment, to provide this.

A light guide according to the present invention refers in particular to a transparent component, for example fibers, tubes or rods, which can transport light over a distance. The light pipe is in this case caused in particular by reflection at the boundary surfaces of the light guide either by total reflection due to a lower refractive index of the medium surrounding the light guide or by mirroring of the interface. The optical waveguide has a light entry side or light input side through which light, in this case preferably the signal light, can be coupled into the optical waveguide. The light guide has a light exit side or light outcoupling side through which light, in this case preferably the signal light, can be coupled out of the light guide. The light exit side opposite the photodetector is preferably arranged.

The idea according to the invention that two light guides are provided can also be transferred to more than two light guides. Thus, more than two optical fibers can thus be provided, which can either direct the light to a single photodetector or to a corresponding photodetector assigned correspondingly to these further optical fibers. That means in particular that in further embodiments, a plurality of optical fibers are provided, that is, more than two optical fibers. In particular, it is then provided according to further embodiments that these multiple light guides conduct light to a single photodetector. In particular, according to further embodiments, it is provided that these multiple light guides each guide the signal light to a separate photodetector. In particular, according to further embodiments, it is provided that some of these multiple optical fibers conduct light to a single common photodetector, whereas others of these multiple optical fibers conduct signal light to a respective separate photodetector.

According to a further embodiment, it is provided that the second optical waveguide is optically coupled to the optical element, so that the signal light which transmits the optical element can be partly coupled into the second optical waveguide as the further part to be guided. In particular, it is provided that, in the case of more than two light guides, these are also optically coupled in an analogous manner to the optical element, so that the optical element transmitting the signal light can be partially coupled into the further light guide as the further part to be guided in each case. The resulting advantages are analogous to the embodiment in which the optical fiber is optically coupled to the optical element.

Generally, for better discrimination, the light guide may be referred to as the first light guide so as to better distinguish it from the second light guide.

In another embodiment, it is provided that the photodetector and / or the light guide are at least partially covered by extraneous light by means of a cover.

As a result, the technical advantage in particular that a negative influence of extraneous light can be reduced even further. This in particular by the fact that the cover shields the extraneous light. Thus, less or no extraneous light reaches the photodetector. In particular, this results in less or no extraneous light to the light guide, so that less or no extraneous light can be coupled into the light guide.

According to other embodiments, a cover for at least partial covering against external light is also provided in embodiments comprising a plurality of light guides and / or a plurality of photodetectors, as explained above.

The cover may in particular also be referred to as a shield. The at least partial covering comprises in particular a complete covering. Light guide and photodetector are covered differently well in another embodiment, that is, that the photodetector is more covered by extraneous light than the light guide. The cover, for example, as a fastening or locking or fixing for the optical element, so the lens, so the Aufstecklinse be used. That is, according to one embodiment, the cover secures or locks or fixes the optical element. The cover thus advantageously has a dual function: cover function and attachment function.

According to one embodiment, it is provided that the optical element, that is to say the lens, that is to say the attachment lens, is fastened or fixed or locked on the cover. Thus, the optical element is particularly well protected against mechanical stress.

A light guide according to the present invention comprises in particular a Lichteinkoppelseite and a Lichtauskoppelseite. In the Lichteinkoppelseite is the signal light coupled or fed. From the Lichtauskoppelseite this injected signal light is decoupled again. The Lichteinkoppelseite is arranged in the beam path of the signal light, so that the signal light can be partially coupled into the light guide. The light outcoupling side is preferably arranged in the region of the photodetector, so that the coupled-out light can reach the photodetector via a short path. In particular, a deflection optics, for example a mirror, is provided in the region of the photodetector which can guide the coupled-out light toward the photodetector. According to one embodiment, the optical waveguide can have a mirrored boundary surface which is shaped or formed in the beam path of the coupled-in light such that it reflects the injected signal light in the direction of the light outcoupling side.

In another embodiment, it is provided that a carrier is provided, wherein the diode and the photodetector are arranged on a front side of the carrier. This means in particular that the photodetector is positioned together with the diode on the front side of the carrier. This causes in an advantageous manner that no backside assembly is necessary, which is usually more complex. In particular, this gives a larger selection of photodetectors. This is because, due to the front side mounting, a more flexible geometry is possible with respect to the directing of the signal light to the photodetector. The signal light can thus be directed, for example, from the side or from the top to the photodetector. The photodetector can therefore have its photosensitive measuring surface or its photosensitive measuring sensor arranged laterally or above. Thus, a variety of different photodetectors for use in a signal generator according to the invention is possible.

According to a further embodiment it is provided that a carrier is provided, wherein on a front side of the carrier, the diode and on one of the front side opposite Rear side of the carrier of the photodetector are arranged. That is, that is, that the photodetector is equipped on the back of the carrier. The photodetector is thus positioned on the back of the carrier. A backside assembly has the particular advantage that the photodetector can be better protected or hidden from extraneous light.

In another embodiment, it is provided that the carrier has a breakthrough extending from the front to the rear, wherein the photodetector on the back of the breakthrough is arranged at least partially covering, wherein the light guide is partially inserted in the breakthrough. The fact that the light guide is partially inserted into the opening, in particular the technical advantage causes the light guide can be securely held. Furthermore, this allows good alignment and easy alignment relative to the photodetector.

In embodiments comprising a plurality of optical fibers and / or a plurality of photodetectors, combinations of the aforementioned carriers with rear or front positioning are possible. In particular, carriers are provided in these embodiments, which comprise one or more openings.

In one embodiment, the carrier is a circuit board, which may also be referred to as a printed circuit board. In English, a printed circuit board is usually referred to as a "printed circuit board (PCB)".

In another embodiment, the support is a DCB substrate. Here, "DCB" stands for "direct copper bonding". Such a DCB carrier comprises, in particular, a ceramic with integrated copper lines and / or copper plated-through holes, so-called vias.

The cover forms according to an embodiment in the decoupling region of the injected signal light a space with a Room wall having an opening through which the light guide is inserted. As a result, the photodetector, which is indeed in the decoupling, even better protected from extraneous light.

FIG 1

eine Baugruppe für einen Signalgeber,

FIG 2

eine weitere Baugruppe für einen Signalgeber,

FIG 3

eine Draufsicht auf eine andere Baugruppe für einen Signalgeber,

FIG 4

einen Signalgeber,

FIG 5, 6

jeweils verschiedene perspektivische Ansichten eines Linsenaufsatzes mit integrierten Lichtleitern für einen Signalgeber und

FIG 7

einen Signalgebereinsatz für einen Signalgeber zeigen.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments which will be described in connection with the drawing

FIG. 1

an assembly for a signal generator,

FIG. 2

another module for a signal generator,

FIG. 3

a plan view of another assembly for a signal generator,

FIG. 4

a signal generator,

FIG. 5, 6

each different perspective views of a lens attachment with integrated light guides for a signal generator and

FIG. 7

show a signal generator insert for a signal generator.

Hereinafter, like reference numerals may be used for like features.

FIG. 1 shows a side sectional view of an assembly 101 for a signal generator. This means that the signal generator according to the invention comprises, for example, this assembly 101.

The assembly 101 comprises a carrier 103, which is formed for example as a circuit board or as a printed circuit board. The carrier 103 has a front side 105. Furthermore, the carrier 103 has a rear side 107, which lies opposite the front side 105. On the front side 105, a light-emitting diode 109 is arranged. The light-emitting diode 109 is formed, for example, as an LED chip. The Light emitting diode 109 radiates light, which corresponds to a signal light. The radiated signal light is symbolically indicated by arrows 110.

The reference numeral 111 points to an LED lens which is arranged on the diode 109 and enables an optical imaging of the signal light 110 emitted by means of the diode 109.

Further, a photodetector 113 is disposed on the front side 105. The photodetector 113 is, for example, a photodiode or a phototransistor.

Furthermore, a slip-on lens 117 is provided, which is arranged in the beam path of the signal light 110. For this purpose, the Aufstecklinse 117 Aufsteckelemente 117 a, for example feet or webs, by means of which the Aufstecklinse 117 is attached or attached to the front side 105. Between the Aufstecklinse 117 and the diode 109 with its LED lens 111, a distance is provided so that between the Aufstecklinse 117 and the diode 109 with its LED lens 111, a gap 115 is formed. By means of the plug-on lens 117 is also an optical image of the signal light 110 allows, for example, a widening or scattering of the signal light 110th

Furthermore, a light guide 118 is provided, which is optically coupled to the plug-on lens 117 and integrally formed therewith. This advantageously has the effect that the signal light 110 can be coupled at least partially into the light guide 118 through a light coupling-in side 118a (shown in dashed lines). The part of the signal light 110, which is coupled into the optical waveguide 118 and is passed on to the photodetector 113, is identified symbolically by arrows with the reference numeral 119. By means of the light guide 118, it is thus advantageously possible to direct part of the signal light 110 from the diode 109 to the photodetector 113. The coupled signal light 119 is coupled out by a light extraction side 118b.

A deflection optics 121 is provided which deflects the guided part of the signal light 110 in the direction of the photodetector 113. The deflection optics 121 is in FIG. 1 is formed as a mirrored interface of the light guide 118, which reflects the coupled signal light 110 in the direction of the photodetector 113. The deflection optics 121 comprises, for example, in a not shown embodiment, a mirror which is formed separately from the light guide 118.

Furthermore, the assembly 101 comprises a cover 123 which covers the photodetector 113. Furthermore, the cover 123 at least partially covers the light guide 118. As a result, it is advantageously prevented or at least restricted that extraneous light can be coupled into the optical waveguide 118 and thus reach the photodetector 113. In particular, this prevents or reduces the possibility that extraneous light can reach the photodetector 113 directly. By virtue of the fact that less extraneous light can reach the photodetector 113, it is advantageously achieved that the signal light 110 can be measured even more accurately. In particular, this improves a signal-to-noise ratio.

The cover 123 therefore covers, in particular, a non-active region of the attachment optics, here the attachment lens 117. The non-active area of the attachment optics is the area of the attachment optics through which no signal light 110 is radiated. This means that this non-active area does not light up when the diode emits signal light 110. In particular, the non-active area may be referred to as a passive area.

Furthermore covers the cover 123 from the part of the light guide 118, which leads from the attachment optics, so here the Aufstecklinse 117 to the photodetector 113. In particular, the cover 123 covers the photodetector 113 itself. The cover 113 may also be referred to as a shading or shielding. The cover 123 forms in Auskoppelbereich of the coupled-in signal light 119 has a space 124 with a chamber wall 125 which has an opening 129 through which the light guide 118 is inserted. As a result, the photodetector 113, which is located in the decoupling area, is even better protected from extraneous light.

The reference numeral 127 points to another on the front side 105 arranged cover for shading or shielding of light. The further cover 127 and the cover 123 partially surround the slip-on lens 117 with the light guide 118. That is to say that the slip-on lens 117 with the light guide 118 is located between the two covers 123, 127. Thus, it can be avoided, in particular in an advantageous manner, that extraneous light can reach the light guide 118 from below, based on the plane of the paper of the drawing.

In the FIG. 1 shown assembly 101 of a signal generator thus has a carrier 103, wherein both the photodetector 113 and the diode 109 are positioned or arranged on the front side 105. So that means that according to the embodiment of the FIG. 1 the carrier 103 has no rear-side mounting, that is to say an assembly on its rear side 107. All elements are thus arranged on the front side 105. This facilitates production of the signal generator 101. In particular, this makes possible a larger selection of photodetectors.

FIG. 2 shows a side sectional view of another assembly 201 for a signal generator. This means that the signal generator according to the invention comprises, for example, this module 201.

The assembly 201 is substantially analogous to the assembly 101 of FIG. 1 built up. As a difference, the carrier 103 has an opening 203. The opening 203 extends from the front side 105 to the rear side 107. As another difference, the photodetector 113 is equipped on the rear side. That is, the photodetector 113 on the back 107 of the Carrier 103 is arranged. Here, the photodetector 113 covers the opening 203. The diode 109 is disposed on the front side 105. Although it is in the drawing of the FIG. 2 so it looks like the photodetector 113 would float freely over the back 107, this is not so. The photodetector 113 is attached to the back 107 by suitable means (adhesive layer and / or solder layer). The drawing of the FIG. 2 shows only a schematic representation.

As a further difference, the optical waveguide 118 extends in such a way that a part of the optical waveguide 118 is inserted into the aperture 203. Thus, therefore, the light which is coupled out of the light guide 118 can pass directly to the photodetector 113. The light extraction side 118a preferably runs flush with the rear side 107.

FIG. 3 shows a plan view of another assembly 301 for a signal generator according to the invention (that is, the inventive signal generator, for example, this assembly 301 includes), wherein the sake of clarity, the carrier 103 is not shown. To see is only the intent optics, so the Aufstecklinse 117, in which case two such Aufstecklinsen 117 can be seen. Because this assembly 301 of FIG. 3 has two light emitting diodes 109. Although not directly visible, reference numeral 109 schematically indicates these two diodes.

Furthermore, the assembly 301 comprises a second optical waveguide 303 which, analogous to the optical waveguide 118, conducts a portion of the signal light 110 from the second diode to the photodetector 113. This means that the assembly 301 according to FIG. 3 two diodes 109 includes, wherein in each case a light guide 118, 303 conducts an equal portion of the corresponding emitted signal light 110 to the photodetector 113 or leads. Again, the Aufstecklinsen 117 and the two light guides 118, 303 as a common component, for example, as an injection molded part is formed.

FIG. 4 shows a three-field signal generator 401.

The signal transmitter comprises three signal fields 403, 405, 407. These signal fields 403, 405, 407 each comprise one of the aforementioned assemblies. The signal generator 401 is part of a traffic signal system according to one embodiment.

FIGS. 5 and 6 each show different perspective views of a lens attachment 501 with integrated light guides 503, 505 for a signal generator. FIG. 6 shows the side of the lens cap 501 facing the LEDs. FIG. 5 shows the side of the lens attachment 501, which faces away from the LEDs. The respective pages are thus arranged opposite each other.

The lens attachment 501 comprises two lenses 507, 509, which have the function of the lenses 117 described above. The lens attachment has two attachment elements 511 that can be used to secure the lens attachment 501 to a carrier 103.

The lens attachment 501 is thus placed or mounted on a carrier 103, as described above, comprising LEDs and a photodetector.

FIG. 7 shows a signal generator insert 701 for a signal generator in a side sectional view. This means that the signal generator according to the invention comprises, for example, such a signal generator insert 701. Such a signaling device insert 701 is used in particular for a field of a signal generator. This means, for example, that the signal generator 401 of the FIG. 4 each has three such signal generator inserts 701 for its three fields.

The reference numeral 703 points to an assembly 703, which is formed analogously to one of the assemblies described above, for example, and which in this case comprises a carrier 103, LEDs, 109 and a photodetector 113, wherein these elements not shown in detail for the sake of clarity. The lens attachment 501 is mounted on the carrier 103.

The signaling device insert 701 has a housing 705 in which the assembly 703 is arranged. Further, an optical lens 707 and a front lens 709 are provided in the optical path of the signal light 110 to further depict the signal light 110. The front lens 709 has, for example, a mask.

• Ein geringer Lichtstromanteil des LED-Signallichtes wird ausgekoppelt.
• Daraus ergibt sich folgende Beleuchtungsstärke in der Photodetektorebene:
  • Auskopplung von 0,05%, welches in der Photodetektorebene auftrifft 100 lm · 0,0005 = 0,05 lm
  • Fläche ca. 4 mm · 4 mm = 1,6 E-5 m² (Photodetektor wird überstrahlt)
  • Beleuchtungsstärke 3,125 lm/m² (lx)
• Zu erwartender Photostrom (grobe Abschätzung):
  • Phototransistor: 220 µA/1.000 lx · 3,125 lx = 680 µA
  • Photodiode: 6,3 µA/1.000 lx · 3,125 lx = 20 µA

In the following, an expected photocurrent is approximately calculated as it passes to the photodetector 113. The values assumed here are exemplary and not restrictive.

• A small proportion of luminous flux of the LED signal light is output.
• This results in the following illuminance in the photodetector plane:
  • Coupling of 0.05%, which impinges in the photodetector plane 100 lm · 0.0005 = 0.05 lm
  • Area approx. 4 mm · 4 mm = 1.6 E-5 m ² (photodetector is outshined)
  • Illuminance 3.125 lm / m ² (lx)
• Expected photocurrent (rough estimate):
  • Phototransistor: 220 μA / 1,000 lx x 3.125 lx = 680 μA
  • Photodiode: 6.3 μA / 1,000 lx x 3.125 lx = 20 μA

The invention thus comprises in summary the following approach in particular:
The new approach is to make an accurate measurement of the light. In the new concept, the light of the LED is bundled via a clip-on lens which is plugged onto the LED in order to direct it to the exit area of the signal generator. A small defined part of the light, which emits the LED is derived by the Aufstecklinse specifically by means of a light guide to a monitor diode.

The light guide and the monitor diode are covered by a screen, so that almost no extraneous light from the outside either directly or by feeding (refraction or reflection) of the light in the Aufstecklinse in the light guide to the monitor diode can be passed. Thus, the amount of light that falls on the monitor diode (generally photodetector), almost exclusively from the LED and can thus be determined exactly.

Furthermore, in another embodiment, the external light component can be determined more accurately by means of a second, independent light guide which leaves the attachment lens and leads either to the same monitor diode or to a second monitor diode (generally the second photodetector). This is due to the fact that the angle of incidence of the extraneous light in the two light guides is different and thereby the amount of extraneous light that is fed into the respective light guide, is different levels. Explanation: if the maximum extraneous light is fed into an optical waveguide (optimum angle of incidence), this will be lower in the second optical waveguide, since the extraneous light will not be incident here at the optimum angle of incidence. By comparing these two values (amount of extraneous light), a part of the ambient light can be eliminated (eliminated).

The inventive step is, in particular, that a part of the light of the LED is directed and bundled over at least one light guide to the monitor diode.

The advantage of this solution lies in the fact that the amount of light that emits the LED can be determined very accurately and that from the outside penetrating light causes no significant interference.

While the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (9)

1. Signal transmitter (401) for a light signal system comprising:

   - a light-emitting diode (109) for emitting a signal light (110),

   - a photodetector (113) and

   - an optical fibre (118, 303) for routing part of the emitted signal light (110) from the diode (109) to the photodetector (113) so that

   - the photodetector (113) can measure the part (119) of the emitted signal light (110) which has been routed away

   - wherein an optical element for an optical mapping of the signal light (110) is provided in a beam path of the signal light (110), wherein the optical fibre (118, 303) is optically coupled to the optical element so that the signal light (110) transmitting the optical element can to some extent be injected into the optical fibre (118, 303) as the part to be routed,

   - wherein a carrier (103) is provided,

   - wherein the optical element is a lens,

   - wherein the diode (109) and the photodetector (113) are arranged on a front side (105) of the carrier (103) or wherein the diode (109) is arranged on a front side (105) of the carrier (103) and the photodetector (113) is arranged on a rear side (107) of the carrier (103) which faces the front side (105),
   characterised in that the lens is formed as a clip-on lens, wherein the lens is clipped or arranged on the carrier (103) .
2. Signal transmitter (401) according to claim 1, wherein a second photodetector (113) and a second optical fibre (118, 303) are provided to route a further part of the emitted signal light (110) from the diode to the second photodetector (113), so that the second photodetector (113) can measure the further part of the emitted signal light (110) which has been routed away.
3. Signal transmitter (401) according to claim 1, wherein a second optical fibre (118, 303) is provided for routing a further part of the emitted signal light (110) from the diode (109) to the photodetector (113), so that the photodetector (113) can measure the further part of the emitted signal light (110) which has been routed away.
4. Signal transmitter (401) according to claim 2 or 3, wherein the second optical fibre (118, 303) is optically coupled to the optical element so that the signal light (110) transmitting the optical element can be partially injected into the second optical fibre (118, 303) as the further part to be routed.
5. Signal transmitter (401) according to one of the preceding claims, wherein the photodetector (113) and/or the optical fibre (118, 303) are covered at least partially from ambient light by means of a cover (123).
6. Signal transmitter (401) according to claim 5, wherein the optical element is fastened to the cover (123).
7. Signal transmitter (401) according to one of the preceding claims, wherein when the diode (109) is arranged on the front side (105) of the carrier (103) and the photodetector (113) is arranged on the rear side (107) of the carrier (103) which faces the front side (105), the carrier (103) has a passage (203) which runs from the front side (105) to the rear side (107), wherein the photodetector (113) is arranged to at least partially cover the passage (203) on the rear side (107), wherein the optical fibre (117, 303) is inserted partially in the passage (203).
8. Signal transmitter (401) according to one of the preceding claims, wherein the optical fibre (118, 303) and the optical element are formed as a shared component, in particular as an injection moulded part.
9. Light signal system, comprising a signal transmitter (401) according to one of claims 1 to 8.

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