Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08G—TRAFFIC CONTROL SYSTEMS
  • G08G1/00—Traffic control systems for road vehicles
  • G08G1/09—Arrangements for giving variable traffic instructions
  • G08G1/095—Traffic lights
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L29/00—Safety means for rail/road crossing traffic
  • B61L29/24—Means for warning road traffic that a gate is closed or closing, or that rail traffic is approaching, e.g. for visible or audible warning
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L5/00—Local operating mechanisms for points or track-mounted scotch-blocks; Visible or audible signals; Local operating mechanisms for visible or audible signals
  • B61L5/12—Visible signals
  • B61L5/18—Light signals; Mechanisms associated therewith, e.g. blinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L9/00—Illumination specially adapted for points, form signals, or gates
  • B61L9/04—Illumination specially adapted for points, form signals, or gates electric
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
  • F21V5/04—Refractors for light sources of lens shape
  • F21V5/045—Refractors for light sources of lens shape the lens having discontinuous faces, e.g. Fresnel lenses
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V5/00—Refractors for light sources
  • F21V5/08—Refractors for light sources producing an asymmetric light distribution
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
  • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
  • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B3/00—Simple or compound lenses
  • G02B3/02—Simple or compound lenses with non-spherical faces
  • G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
  • B61L2207/00—Features of light signals
  • B61L2207/02—Features of light signals using light-emitting diodes [LEDs]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
  • F21W2111/00—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00
  • F21W2111/02—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00 for roads, paths or the like
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
  • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
  • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
  • G02B19/0066—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED in the form of an LED array
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0018—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for preventing ghost images
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/003—Light absorbing elements

Definitions

• a signal lamp intended, in particular, for optical signal indicators for road traffic control
• the proposed solution relates to outdoor optical signal indicators intended road traffic control in particular, on level crossings, and addresses a new embodiment of a signal lamp provided with a central light source based on utilising the LED (Light-Emitting Diode) technology.
• LED Light-Emitting Diode
• LED technology as a light source for optical signal lamps, e.g. for traffic lights and warning boards, has become quite commonplace as they are mainly used thanks to their energy efficiency, higher reliability and durability, and reduced space requirements for integration in the signal lamps compared to incandescent signal lamps.
• matrices of commercially available high-performance LEDs were used, wherein a high number, usually of several tens of units, were spatially laid out to fill a major part of the active, light-emitting surface of the signal lamp.
• the LEDs were usually placed on the same plane on a printed-circuit board, which was often of a circular shape following the shape of the active, light-emitting surface of the signal lamp.
• Placed in front of the LEDs was an optical cover to protect the LEDs from potential mechanical damage from the outside, provide weather protection, and often use its optical properties to adjust the direction of the beams emitted by these LEDs, i.e. angular distributions of luminous intensity, and/or complete the overall desired colour of the light emitted by the signal lamp.
• the number of LEDs connected in series or in series-parallel makes it difficult to identify a failed LED, and increased number electrical components in the case of separate power supplies used to power each group of LEDs degrades the reliability of the signal lamp because the failure rate of the signal lamp increases. If all the LEDs used are powered by a single power supply, a single failure leads to turning the signal lamp off completely. If one of the power supplies fails, a part of the LEDs or their group turn off completely, resulting both in a reduced overall luminose intensity of the signal lamp and in an adverse effect on the luminance uniformity of the active surface of the lamp and a deteriorated perception of the desired homogeneous light. A failure of one or multiple LEDs results in reducing the overall luminose intensity of the signal lamp and a potential adverse effect on the luminance uniformity of the active surface of the signal lamp and a deteriorated perception of the desired homogeneity of light.
• EP0860805 discloses an embodiment of an optical system using a plurality of high- perforrnanoe LEDs arranged on a printed-circuit board (PCB) so that the optical beams emitted by these LEDs and passing through a suitably positioned condenser are scattered in the desired directions by a divergent lens.
• PCB printed-circuit board
• the disadvantage of this solution is that a number of LEDs are used, wherein a potential failure of one or some of them reduces the overall luminous intensity of the signal lamp, changing the spatial distribution of luminous intensity. As the distance of the LEDs from the optical axis of the condenser increases, the efficiency of the forward transmission of the light decreases.
• the number of LEDs used precludes their potential arrangement in close proximity of the optical axis of the condenser, which may lead to an increased energy demand of this solution.
• a potential use of individual separate condenser lens in front of each LED may adversely impact the luminance uniformity of the active surface of the signal lamp and impair the perception of the desired homogeneous light, especially if a LED fails.
• the plurality of LEDs used leads to a reduced reliability of this design and makes it difficult to identify a potentially failed LED because an increased overall failure rate may be expected given the higher number of components used.
• EP0905439 discloses an embodiment of a signal lamp utilising a plurality of high- performance LEDs arranged suitably on a printed-circuit board so that the optical beams emitted by these LEDs and passing through separate condenser lenses placed preferably in front of each LED are scattered in the desired directions on the outer cover ring.
• the disadvantage lies in the high number of LEDs used, wherein a potential failure of one or some of them reduces the overall luminous intensity of the lamp, changing the spatial distribution of luminous intensity.
• each LED may adversely impact the luminance uniformity of the active surface of the signal lamp and impair the perception of the desired homogeneous light, especially if a LED fails, but this undesirable phenomenon is mitigated as the number of LEDs used increases.
• the higher number of LEDs used leads to reduced reliability and a potential increase in undesirable phantom signal and a complicated identification of any potentially failed LED.
• the solution disclosed in EP1091167 uses single units of high-performance LEDs, preferably arranged in groups with at least two LEDs per group in a horizontal arrangement, on a printed-circuit board so that the optical beams which are emitted by these LEDS and pass through both separate condensers placed preferably in front of each group of LEDs and a lamellar grille that lowers the undesirable phantom signal are scattered in the desired directions by a scattering screen.
• a relatively large number of LEDs are still used, and they are placed in groups wired in such a way that a failure or malfunction of one LED does not affect the operation of the other LEDs in the same group, but it may cause LEDs in other groups to fail to light, thus reducing the overall luminous intensity of the signal lamp.
• each LED may adversely affect the luminance uniformity of the active surface of the signal lamp and impair the perception of the desired homogeneous light, especially if a LED fails.
• the presence of the lamellar grill significantly eliminates the undesired phantom signal, it reduces the efficiency of the emission of the signal lamp's light in the directions concerned to a certain degree and it may also affect the homogeneity of the active surface of the lamp signal.
• Another disadvantage is that the cover of the signal lamp, which fixes the position of the PCB fitted with LEDs, the condenser, the lamellar grilled, and the scattering screen, does not perform the heat dissipation function, and an additional heat sink must be installed on the PCB to dissipate heat from the individual LEDs.
• the solution according to US11155285 intended particularly for optical signalling in railway traffic, discloses a plurality of high-performance LEDs arranged preferably on a printed-circuit board so that the optical beams emitted by these LEDs pass through four optical lenses arranged sequentially in the axial direction relative to the LEDs for diverging and collimating the emitted light beams.
• This optical system is configurable, and the properties, in particular, the distribution of luminous intensity the light emitted by the optical system, i.e. the signal lamp, can be changed by changing the axial position of the third tens, designed as a Fresnel tens, and the design of the fourth, outer tens.
• the solution with preferably suitable for railway signal lights installed along straight as well as curved tracks.
• the disadvantage is the use of a high number of LEDs, one in the centre and others arranged at regular intervals to form a circle around it, where the failure of any of them results in an overall reduction of the luminous intensity of the signal lamp.
• the number of LEDs used reduces the reliability of the lamp and complicates the identification of a potentially failed LED.
• the proposed optical system falls to eliminate the undesirable phantom signal light, and the use of individual convex lenses in front of each LED adversely affects the luminance uniformity of the active surface of the signal lamp and impairs the perception of the desired homogeneous light in case an LED fails.
• EP0415026 discloses a system of a separate lamp housing which contains the light source with the necessary cooling, and the light is conducted from this place to a remote signal lamp via optical light guides. Placed suitably in the signal lamp all over the circular area of the lamp in front of the optical light guides entry are lenses to scatter the beams in the desired directions, and they are protected by a front cover from, the outside.
• the disadvantage of this design is that the failure of the single light source installed in the lamp housing results in the undesirable extinguishment of the whole signal lamp.
• the principle of a separate lamp housing and the transmission of light via optical light guides to a remote signal lamp is also structurally unsuitable for controlling traffic via light signals on roads.
• the use of individual and separate circular lenses in front of each light guides entry may adversely impact the luminance uniformity of the active surface of the signal lamp and impair the perception of the desired homogeneous light.
• the design is adapted for use of an omnidirectional light source, i.e. an incandescent bulb, typically a halogen one, rather than an LED, which causes a low energy efficiency of the system, as the design is proposed to facilitate the replacement of the light source in case of its failure.
• EP1107210 discloses the use of a lower number of high-power LEDs arranged specifically over the PCB in three rows with identical spacing and eight columns with different spacing, offset to form a defined angle with the axis of the signal lamp so that the light beams emitted by these LEDs passing through a suitably placed condenser in the form of a Fresnel Lens are scattered on in the desired directions on the outer diffusion screen.
• This embodiment of the lamp significantly eliminates the undesirable phantom signal.
• There is still a relatively high number of LEDs used, and a potential failure of one or more of the LEDs reduces the overall luminous intensity of the signal lamp.
• the number of LEDs used decreases operational reliability and makes it difficult to identify the failed LED, and the failure of an LED may undesirably affect the distribution of luminous intensity of the light from the signal lamp and impair the perception of the desirable homogenous light. Placing the LEDs outside the focal point of the condenser, the so-called defocusing of the image, reduces the efficiency of the transmission of light forward, which effect is more apparent as the distance of the LED increases.
• the description provided in US20190011114 discloses a structural arrangement of a signal lamp consisting of a light source, preferably comprising a plurality of LEDs placed on a PCB, an inner lens that is mechanically connected to and forms a single unit with this PCB, and an outer lens, which is mechanically connected to the lamp housing.
• the light beam generated by the LEDs is directed out of the signal lamp via the two lenses in the desired direction. If the LED or other components placed installed on the PCB fail, the unit, including the inner lens, may be replaced without the need to remove the outer lens by opening the front of the lamp housing. The replacement of a faulty part of the lamp is done from the front of the signal lamp, which may not be spatially convenient in many instances.
• the PCB with the LEDs also contains electronic components, therefore the probability of a failure and, consequently, of the need to replace the PCB is higher and rises with the number and type of these components. The optical properties of the signal lamp are not affected by this embodiment at all.
• the design embodiment of the lamp according to WO2022183230 intended, in particular, for optical signalling in railway traffic, eliminates as far as possible the undesirable phantom signal by inclining the outer optical cover by a downward angle of 45° or more. This embodiment also eliminates fouling of the outer optical cover and allows for extending the maintenance intervals.
• a suitable design arrangement for the position of the heating element eliminates snow build-up on the outer lens.
• the disadvantage is in complex optical design of the lenses applied. Thanks to the specific design of the optical system, which significantly eliminates undesirable phantom signal, the light beams of the signal lamp are defined and directed only to the sides and downwards from the horizontal axis of the lamp.
• the use of a single central light source comprising two galvanically separated point light sources provides for high availability of the lamp and its operation with a reduced failure rate. Thanks to the proposed suitable optical system, the required optical parameters such as light homogeneity with a luminance uniformity, sufficiently low undesirable phantom signal, chromaticity, and spatial distribution of luminous intensity, are achieved while meeting the requirement for minimum thermal stress on all the components of the lamp.
• the invention is a signal lamp intended, in particular, for optical signalling in road traffic control, with the optical system of the lamp comprising a central light source placed on a printed-circuit board attached removably to the body, a condenser, preferably a Fresnel lens, and an optical cover.
• the central power source consists of at least two point light sources, preferably LEDs, and that placed between the condenser and the optical cover is a diverging element that is formed by a flat disc the contour of which is identical with the contour of the condenser and the front exit face of which is shaped concentrically towards the optical axis of the system, wherein the point light sources are placed on the printed-circuit board at a focal distance in close proximity to, and symmetrically with regard to, the optical axis of the condenser, and wherein the printed- circuit board is attached to the body via a thermal pad that is mounted to the face of the cutout created above the opening of the entrance face of the hollow body.
• the front exit face of the diverging element is shaped concentrically to ensure that the light is directed from the axis of the optical system towards the edges of the diverging element, wherein the entrance inner face of the dispersion element is planar and perpendicular to the optical axis.
• the front exit face of the diverging element is shaped concentrically to ensure that the light is directed from the axis of the optical system towards the edges of the diverging element, wherein the entrance inner face of the dispersion element is stepped and perpendicular to the optical axis.
• the point light source consists of one or a plurality of LEDs, and the optical cover is shaded to sufficiently prevent undesirable phantom signal.
• the point light sources be galvanically separated to enable separate independent and redundant use of either of the two point light sources placed symmetrically in the horizontal plane with regard to the optical axis and that the printed- circuit board, thermal pad, and body be made of a highly thermally conductive material, in particular, of copper or aluminium, to ensure heat dissipation from the point light sources while keeping the performance parameters of the point light sources stable.
• the invention achieves a new and higher luminous effect in that the use of a single central light sources comprising two separate light sources (LEDs) placed in close proximity to the focal point of the condenser achieves higher operating efficiency and high full operational availability of the lamp in that a potential failure of one point light sources results in the other point light source (LED) of identical parameters coming on, with the resulting performance of the lamp as a whole remaining at the same desired level.
• LEDs light sources
• Another advantage of the solution consists in the simplified detection of the failure of a functional point light source and its power supply in that if either of them fails, resulting in the failure of the entire one point light sources and in the other point light sources coming on via the latter’s dedicated power supply, so that the signal lamp continues to operate with the required, visually unaltered optical performance parameters.
• the present design of the signal lamp includes a body that holds the two point light sources in the defined position in close proximity to the focal point of the condenser (a Fresnel lens) and is used at the same time as the heat sink to dissipate the heat generated by the supply current passing through the point power source to emit it into the surroundings of the signal lamp over the PCB manufactured using the IMS (Insulated Metal Substrate) technology and the thermal pad.
• the final design guarantees simplified maintenance of the signal lamp, as it is possible to easily replace the PCB assembly fitted with the central light source and body, or the condenser or diverging element by a simple disassembly and assembly operation from the back of the signal lamp in case of a failure.
• the present solution also allows for both limiting the occurrence of unwanted phantom signal by applying a light-absorbing layer on the inner part of the body and the PCB from the side of the installed central light source and by using a suitably shaded material of the outer optical cover, and for ensuring high luminance uniformity of the optically active area of the signal lamp even if either point light source fails, without any visually perceptible change
• Fig. 1 is a side sectional view of the signal lamp divided into two assemblies, showing the passage of light;
• Fig. 2 is an axonometric view of an exploded embodiment of the signal lamp
• Fig. 3a is a partial frontal axonometric view of an exploded embodiment of the signal lamp from Fig. 1 ;
• Fig, 3b) and Fig. 3c) are different alternative embodiments of the PCB fitted with two point light sources in the vicinity of the optical axis;
• Fig. 4 is a partial rear axonometric view of an exploded embodiment of the signal lamp from Fig. 1;
• Fig. 5a) and 5b) are side views of two alternative embodiments of the diverging element showing the passage of light.
• Fig. 6a) to Fig. 6d) are the front, rear, and sectional views of the optical cover and a detail of the central part of the exit face of the cover, respectively.
• the drawings illustrating the present invention and the following examples of particular embodiments do not in any way limit the scope of protection stated in the definition, but merely illustrate the principle of the invention.
• the signal lamp in its basic embodiment shown in Fig. 1 consists of a central light source comprising two separate, galvanically separated point light sources 1 of identical parameters, installed on the printed-circuit board 2 (DPS) attached to the body 3, a condenser ⁇ , a diverging element 5, and an optical cover 6.
• DPS printed-circuit board
• the central light source consists of two galvanically separated point light sources 1, each of which consists of a single LED (Light-Emitting Diode) of identical parameters in the basic embodiment.
• the two LEDs are placed symmetrically at a focal distance in the area of (close proximity to) the optical focal point of the condenser 4 (a Fresnel lens) situated on the optical axis o, wherein the wavelength of the optical beams emitted by the LEDs used defines the overall required colour of the light emitted by the signal lamp.
• a central light source emitting white light of a suitable colour temperature and obtain the desired final colour profile of the lamp by suitably tinting one of the other elements of the optical system.
• the point light source 1 may be physically formed by a single light-emitting chip placed in a defined housing (component) or a very small number of chips placed in one or multiple housings, always so that full operational redundancy can always be ensured for this point light source 1 while being placed at the focal distance in close proximity to the optical focal point of the condenser 4 (Fresnel lens).
• the resulting light from the signal lamp is always emitted by only one light source 1., in the optimal exemplary embodiment shown, by a single LED of the point light source 1, where the both of point light sources 1 (the LEDs used) are selected so that they are interchangeable in terms of the resulting optical parameters of the signal lamp. Any failure of one of the point light sources 1 (i.e.
• LEDs is thus optically imperceptible provided that the system immediately switches to the other point light source 1 , and the signal lamp continues to meet all the required optical parameters and the optical perception of the light generated by the signal lamp remains unchanged.
• the PCB 2 is optimally made using the IMS (Insulated Metal Substrate) technology to ensure that most efficient dissipation from the LED chips of the heat generated by the passage of the supply currents. It is a printed circuit that enables galvanically separated power to be supplied to the two point light sources 1 (i.e. LEDs) via the terminals, connectors or directly soldered circuits placed on the board; it attaches the central light sources in the defined position and carries off heat from it with sufficient efficiency so that the temperature of the two point light sources 1 does not exceed the value that guarantees sufficient stability of parameters and high operational reliabiiity.
• IMS Insulated Metal Substrate
• the PCB 2 with the IMS technology with a copper or aluminium core may be used, but the use of other materials with suitable thermal and electrical properties is not excluded.
• the shape of the PCB 2 does not need to be oval; it may be of any shape provided that the above requirements are met.
• the PCB 2 is removably mounted to the body 3 via a thermal pad 21 and it is secured to the face of the cutout 314 created above the opening 311 of the entrance face 31 of the hollow body 3, the cutout 314 being of the same circumferential shape as the thermal pad 21 and the PCB 2. Acting as a fixing element for ataching the PCB 2 and as a heat sink of sufficient thermal conductivity that guarantees a suitable stability of the parameters of the LEDs used, the body 3 of the lamp together with the PCB 2 with the two point light sources 1.
• the exit face 32 of the body 3 is provided with a circumferential collar 321 , the outer circumference of which includes three evenly spaced tabs 322 to enable the detachable connection of the assembly to the lamp housing (not shown), preferably by means of pins, bayonet-locking connector, or other standard connecting elements (not shown).
• the body 3 is optimally made of a low-weight heat-conductive material, such as a cone-shaped aluminium alloy, and Its outer surface is provided with a plurality of projections 33 suitable for dissipating heat by enlarging the surface area, for example, by longitudinal ribbing, as shown In detail in Fig. 3a) and Fig. 4.
• the surfaces of the inner part of the body 3 and DPS 2 fitted with the light sources 1 are provided with a surface layer (not shown), for example, matt black, to reduce the reflectance of the light to eliminate undesirable phantom signal.
• the central sight source i.e. the two physically separate light sources .1 placed symmetrically horizontally side by side and installed on the PCB 2
• the point light sources 1. may be executed as two LEDs or a series of LEDs placed in close proximity to the optical axis o.
• the condenser 4 and the diverging element 5 are housed within the interior of the optical cover 6, as shown in Fig. 1, which is detachably connected to the structure of the lamp housing structure (not shown).
• the condenser 4 is executed as a Fresnel lens, which reduces the spatial demand of the entire optical system.
• the Fresnel lens captures the light generated by the point light source 1 over a wide range, and collimates the beams directed to the diverging element 5.
• the diverging element 5 being the divergent element in the optical system, consists of a fiat disk the contour of which is identical to that of the condenser 4 and the front exit face 51 of which is shaped concentrically, i.e. with regard to the optical axis o, so that, on the edge of the disk from the axis g of the optical system, the light is directed towards the edges of the diverging element 5, which is beneficial for the overall spatial distribution of luminous intensity.
• the entrance inner face 52 does not need to be planar and perpendicular to the optical axis g: instead, it may be stepped or of another shape.
• the material of the diverging element 5 may be completely clear or tinted in a defined manner, which may affect the optical parameters of the lamp such as the luminance uniformity, phantom signal, and other properties.
• the optical cover 6 forms the outer part of the proposed optical system, and, in terms of the transmission of the optical beams, it is a diffuser of a circular shape that homogeneously scatters the passing beams in a defined direction. It consists of individual shaped diffusion elements 62 (lenses) arranged over its the entire active area, as shown in Figs. 6 a), 6c), and 6d), The individual diffusion elements 62 of the optical cover 6 are shaped so as to direct at each point the passing light in a defined manner so that the resulting spatial distribution of luminous intensity meets the requirements applicable to road traffic control lamps, including the standard requirements for warning boards in the direction above the axis of the light.
• the defined tinting of the optical cover 6 material significantly eliminates the undesirable phantom signal without affecting the chromaticity of the resulting light from the signal lamp to comply with the standard requirements applicable to road traffic control lamps. At the same time, the tinting of the optical cover 6 material eliminates the amount of light (sunlight) that may potentially enter the lamp from the front, posing a potential excessive heat danger to the point light source 1 used.
• the optical cover 6 is made of durable material such as polycarbonate, which is selected to ensure that its mechanical resistance protects the entire optical assembly from external influences.
• the optical cover 6 is positioned perpendicularly to the optical axis g of the signal lamp, but an incline of the vertical plane of the optical cover 6 is not excluded, for example, to reduce undesirable phantom signal.
• the active area 61 of the optical cover 6 is convex towards the outside of the signal lamp, but a flat shape of the optical cover 6 is not excluded.
• the entire optical system of the present embodiment is preferably intended to be incorporated in a road traffic control light housing, in particular for the warning boards of level crossing systems, etc.
• the resulting chromaticity of the light emitted by the signal lamp embodiment described herein is determined exclusively by the type of the point light sources 1. (LEDs) used.
• the signal lamp according to this invention is intended, in particular, for optical signal indicators intended for road traffic control, especially for incorporation in warning board housings provided on level crossings.

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• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Optics & Photonics (AREA)
• General Engineering & Computer Science (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Road Signs Or Road Markings (AREA)

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• 2023
  • 2023-02-17 CZ CZ2023-61A patent/CZ309937B6/cs unknown
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  • 2024-01-22 WO PCT/CZ2024/000001 patent/WO2024170013A1/en active Pending

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