Communications: electrical – Land vehicle alarms or indicators – Internal alarm or indicator responsive to a condition of the...
Reexamination Certificate
2000-08-29
2001-08-28
Lefkowitz, Edward (Department: 2632)
Communications: electrical
Land vehicle alarms or indicators
Internal alarm or indicator responsive to a condition of the...
C340S459000, C313S510000, C362S489000
Reexamination Certificate
active
06281788
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The invention concerns an indicating instrument which is intended for a motor vehicle and has an illuminable display with a light-emitting substance which can be activated between two electrodes.
In the case of such indicating instruments, for indication purposes it is generally necessary to provide display areas which, in simple configurations, visually present the current situation to the user merely by means of a correspondingly illuminable character. While in the past respectively separate filament lamps together with a corresponding shield were used for this purpose, nowadays increasing use is being made of light sources which, apart from a low overall height and high operational reliability, also particularly permit illumination over a surface area.
A corresponding display has been realized for example by a substance consisting of phosphorus being induced to produce light emission by means of the two electrodes. By appropriate shaping of the electrodes or of the phosphorus layer, this allows characters or symbols to be depicted without an additional shield, then appearing for example as a light area before a dark background. In a similar configuration, background illumination is also provided, so that the characters or symbols become visible due to their contrasting color before an illuminated background.
When such illuminating means have been used in practice, it has proven to be disadvantageous that the customary indicating instruments usually have not only those displays which represent simple switching states, such as for example on/off, but in addition also other forms of representation such as pointer instruments, illuminated strips and increasingly also liquid crystal displays (LCDs), which each require a type of illumination matched specifically to them. For example, liquid crystal displays require transmitted-light illumination, in which the light spectrum undergoing a change as it passes through has to be taken into consideration, while dials for pointer instruments require uniform illumination of the scaling and possibly also active illumination of their pointer vane in a contrasting color. Furthermore, it is increasingly desired from design considerations for the indicating instrument to have a dark surface, so that the display only becomes visible to the viewer by means of corresponding illumination and thereby permits information to be provided on an individual, need-related basis.
There have already been attempts to illuminate the different components simultaneously by means of the actively illuminating display, in order in this way to simplify the construction and obviate the need for additional light sources. In practice, it has proven disadvantageous in this respect that either the luminous intensity of the display was not adequate, or was so only in a certain color spectrum, for illuminating further displays, or else the possibilities for shaping the displays were greatly restricted, so that the area of application was considerably restricted. In addition, undesired light changes occur at the interfaces of neighboring displays, leading to an inferior visual appearance of the indicating instrument.
SUMMARY OF THE INVENTION
The invention is therefore based on the problem of providing an indicating instrument of the type stated at the beginning in such a way that simple illumination of the display is achieved.
This problem is solved according to the invention by the substance being a light-emitting polymer (organic LED, abbreviation: OLED), which is designed such that it can be activated both for the background illumination and for the representation of image dots or characters.
As a result, the polymer can be used in the indicating instrument as a commonly shared light source for displays with any desired forms of representation. The high luminous intensity which can be achieved with the polymer also at the same time permits unproblematical transmitted-light illumination of liquid crystal displays. Furthermore, this also allows a so-called black panel display to be realized, in which the plane of representation of the display is exclusively visible when the illumination is switched on, whereas the front side of the indicating instrument appears as a substantially dark surface when the illumination is not switched on. At the same time, the polymer has a comparatively low overall height, so that in particular very flat embodiments of the indicating instrument can also be achieved, with an extended area of use. The polymer may in this case serve both for illuminating further displays and, by itself being shaped for example in the form of a symbol or a figure, directly as the display itself, in that the area determined by the figure or symbol is highlighted against the background when it is correspondingly activated. The polymer, also known as LEP (Light Emitting Polymer) or OLED (Organic Light Emitting Diode, see above), also has a low energy consumption and is easier to read by virtue of its increased viewing angle. At the same time, the entire light spectrum can be depicted, so that in particular there is no longer any need for light filters. Furthermore, the high response rate permits a quickly changing image sequence, so that in particular information relevant to safety as well can be reliably displayed by means of the polymer.
A particularly advantageous embodiment of the invention is provided by the electrodes being produced from a plastic. This allows the laminated construction of the indicating instrument to be further reduced in its overall height, in that the electrodes are for example made in the form of foil. At the same time, this allows the weight of the indicating instrument to be reduced, so that a much extended area of use is obtained.
The indicating instrument according to the invention advantageously also has a high mechanical stability with lower overall height if the electrodes are each applied to a substrate of plastic or glass.
At the same time, a particularly favorable development of the invention is provided by the electrodes and the polymer enclosed between them being capable of being shaped. This allows an indicating instrument which can be optimally adapted to the surface characteristics of the dashboard of the motor vehicle to be realized. Apart from the attractive visual appearance associated with this, a shaping of the indicating instrument adapted to visual capabilities and external influences in the interior compartment of the motor vehicle and at the same time improved ease of reading and consequently increased safety are achieved. For example, this allows disturbing reflections on the front side of the indicating instrument to be avoided in a simple way.
The indicating instrument may be provided exclusively with displays which visually present the desired information to the user only by their activation as an illuminated or non-illuminated region. On the other hand, another particularly advantageous embodiment of the invention is achieved by the indicating instrument having a pointer instrument. In this way, information can be presented in the conventional way and can be registered by the user even from a quick glance. At the same time, the polymer permits illumination of the background over a surface area, it also being possible for the pointer instrument to be integrated into the indicating instrument in such a way that it is highlighted against the background, and consequently readable, only when the illumination is switched on. In addition, the pointer of the pointer instrument may also be actively illuminable—for example by means of OLEDs applied to its vane.
Particularly well suited for this is a configuration of the indicating instrument according to the invention in which the polymer has an opening for a pointer spindle intended for the deflection of a pointer vane of the pointer instrument. This allows the pointer vane to be arranged such that it can pivot a small distance in front of the polymer, so that a sharp contrast between the pointer vane and the background, and conse
Farber Martin A.
Lefkowitz Edward
Mannesmann VDO AG
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