Patent Application
20050068771
1. Field of the Invention
The present invention relates to a signal that includes side emitting status indicators, and in particular in which the signal includes an LED light source. Such a signal can find application, for example, as a railway indicating signal.
2. Discussion of the Background
A typical railway indicating signal utilizes an incandescent light bulb as a light source. Such a railway signal may be employed at a railway crossing. In that type of signal the light emitted from the incandescent light bulb passes through at least one red lens to provide a primary red signal to an oncoming motorist crossing the rail tracks. Also, two additional light ports, one on each side, may be provided to provide objective evidence to a train operator that the light bulb is properly outputting light to the oncoming motorist. That is, an operator on the train can view light output from the additional light ports to confirm that the light bulb in the railway crossing light is properly operating. In that operation the light provided to the additional light ports is directly collected from the light source, i.e., the incandescent light bulb, by an optical window that utilizes prism features, and which refracts light in the desired direction.
One object of the present invention is to provide a novel signal, such as a railway indicating signal that utilizes an LED light source and that provides an accurate side emitting status indication.
The present inventors have recognized that as LED light sources become more and more available, LED light sources may be utilized in signal applications. However, most LEDs provide substantially directional light. In the context of a railway signal, the light output by an LED light source may pass through a lens or lenses providing signals to oncoming motorists. In such a case, since the LEDs provide substantially directional light, in a device such as a railway light with side emitting status indicators, there is typically insufficient light reaching the side emitting status indicators for a train operator to view because of the directional nature of the LEDs.
One way to solve that problem is to add additional LEDs to be directed to the side emitting status indicators. However, that approach does not provide a failsafe indication to a train operator since those additional LEDs may not always operate the same as the primary LEDs providing the light signal in a primary direction to an oncoming motorist. That is, the situation may arise that the LEDs providing a light signal in a primary direction to an oncoming motorist are not properly working, but different side facing LEDs providing light in a secondary direction to side emitting status indicators are properly working. In that instance, the train operator would not be given on accurate indication.
Accordingly, a more specific object of the present invention is to provide a novel LED signal with side emitting status indicators that provides a true indication of the light provided in a primary light output direction.
To achieve the above and other objects, the present invention sets forth a novel light device including a light source of at least one LED configured to generate light in a primary direction. A lens device through which the light generated from the light source passes is also provided. That lens device, however, also reflects a portion of the light generated from the light source. Collection optics are configured to capture the reflected portion of the light generated from the light source, and are configured to output the captured reflected light in a direction other than the primary direction, i.e. in a direction for the side emitting status indicators.
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection to the accompanying drawings, wherein:
Referring now to the drawings, wherein like reference numerals identify identical or corresponding parts throughout the several views, and more particularly to
As shown in
The light device 10 also includes two lenses of an inner lens 2 and an outer lens 3. Light output from the LEDs 1 predominantly passes through the inner lens 2 and the outer lens 3 in a primary direction to provide a light indication signal. In the context of a railway indicator an oncoming motorist will view the light output from the LEDs 1 and passing through the inner lens 2 and the outer lens 3.
The light device 10 also includes additional side emitting status indicators formed of elements 4-8. The side emitting status indicators provide an indication signal in a direction other than the primary direction from which light from the LEDs is output. Element 4 is a light pipe that directs light collected at a collecting surface 7 to an exit surface 8. The exit surface 8 can be frosted to provide a diffused uniform illumination. The light pipe 4 may be made from plastics or glass or other optical materials. The light pipe 4 is held in place by a sleeve 5. In the context of a railway indicator, a train operator will be able to view light output from the exit surface 8 to have an indication whether the LEDs 1 are properly operating, and to thereby give an indication whether an oncoming motorist is receiving a proper indication signal.
The operation of the output of light from the LEDs 1 is shown in further detail in
With reference to
It is also the case that some light beams 13 output from the LEDs 1 will directly impinge on the collecting surfaces 7 of the light pipes 4 and also travel through the light pipes 4 and result in the side emitting beams 14. In fact, it may be adequate for only these light beams 13 to be collected if those light beams 13 provide enough illumination in the side emitting beams 14. In that instance the reflected Fresnel loss beams 12 need not be collected, although in an embodiment both the Fresnel loss beams 12 and direct light beams 13 are collected.
Further details of the side emitting status indicator light collecting devices of elements 4-8 is shown in
Further, since the collecting surfaces 7 of the light pipe 4 are placed near the edge of the housing 6, as shown in
Such a structure of the light device 10 provides side emitting signal indicators that provide a true indication of the light output from the same LEDs 1 providing light in a main light output direction. Thereby an enhanced safety operation is achieved.
The light device 10 as described above has been mainly described in the context of a railway indicator signal. However, it is apparent to those of ordinary skill in the art that the light device 10 can be used in other contexts in which a side indication whether a light signal is being output in a primary direction is desirable.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
