JP2675278B2 - Device for illuminating the control key of a charge meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for illuminating a control key of a charge meter, comprising a two-part casing, a printed wiring board supporting an electronic computer of the charge meter and a data memory. A liquid crystal display, an optical waveguide for illuminating the liquid crystal display on the back side, and a glass plate corresponding to the liquid crystal display on the front side,
A control key that is exposed on the front side and that can be directly operated by hand is provided, and the contact key formed on the printed wiring board can be short-circuited by the control key.

[0002]

2. Description of the Related Art As is well known, a fare meter is used in a rented vehicle to calculate a running fare and display it on a display. Around the toll meter, other various vehicle equipment and devices that must always be located within the driver's operating range are also densely arranged, and the lighting characteristics inside the vehicle depend on the time of day and weather conditions. Because of the large fluctuations, it is advantageous to be able to better recognize the normally frequently used control keys of the charge meter, in order to avoid erroneous operation even when the charge meter is momentarily observed. The control key of the charge meter is the circuit connection of the instrument,
It works for selecting a fare level, switching between "rental" and "empty" states, calling and displaying the control counter state, displaying and adding a premium.

The current trend towards miniaturization, namely the need to aesthetically integrate a toll meter into a dashboard, and thus the use of a dedicated built-in space or a built-in space left by another vehicle instrument and instrumentation. Considering this, the size of the key surface is inevitably reduced, so that by illuminating the control key, the risk of mistakes can be avoided and a reliable operation can be guaranteed. Of the control key with each one lighting element,
Direct lighting or transmissivity, which itself can be easily realized, is an additional considerable effort.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is therefore to improve a device of the type mentioned at the beginning such that the control keys of a charge meter can be transilluminated with the least possible effort. It is to provide a device.

[0005]

In order to solve this problem, in the structure of the present invention, the key shaft portion of the control key is made of a photoconductive material, and corresponds to the optical waveguide and the key shaft portion. The guideway to be used is integrally molded.

[0006]

According to the present invention, the control key of the charge meter can be projected through with the least possible effort. In an advantageous configuration of the invention, the combination of the components forming the charge meter component unit, namely the printed wiring board, the switching mat integrally formed with the photoconductive key shaft, and the guide corresponding to the key shaft. The combination with optical waveguides with channels offers great advantages. This reduces the required number of components to a minimum compared to the known prior art and makes the assembly considerably easier. That is, the control key is indirectly assembled by coupling the printed wiring board and the optical waveguide. At the same time, a translucent material is used for the key shank, so that a sufficient transmission of the control key for said purpose is obtained. In addition, this sufficient transmission is based on the specified arrangement of the optical waveguide and the light-emitting diode acting as a light source, and in particular, a light-injection coupling with a small loss to the optical waveguide can be obtained, and the guide path is sufficiently well formed by a light beam. It can also be obtained by being satisfied.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows the front of a general-purpose charge meter 1. The toll meter 1 is provided with a glass plate 2, which acts as a face plate. On the glass plate 2, display means of the charge meter 1,
A transparent area 3 for viewing the liquid crystal display 4 is preferably partitioned. The casing of the charge meter 1 is
It consists of a frame-shaped front casing component 5 and a dish-shaped rear casing component 6 (see FIG. 2). The charge meter 1 further includes control keys indicated by reference numerals 7, 8, 9, and 10, and a recognition display plate 11. The control keys 7, 8, 9 and 10 are formed in a web shape. This allows a reduction in structural height, but still allows a sufficiently reliable operation. The reference numeral 12 designates a cover for a so-called service compartment. In the service compartment, the connector base for the parameterized connector and the diagnostic connector and the buffer battery are accessible. Sign 1
Reference numerals 3 and 14 denote recesses, and a sealing cap corresponding to a fixing screw can be inserted into the recesses 13 and 14 at the time of assembling the charge meter 1 at an assembly site. Sign 1
Reference numerals 5 and 16 denote holes that serve to guide the fixing screw through. The screws (not visible in FIG. 1) that connect the two casing components 5, 6 to one another are locked by the sealing body 17.

FIG. 2, which shows a sectional view, shows the main constituent elements or functional elements of the charge meter 1 in a functional state. That is, the glass plate 2 is the casing component 5
The liquid crystal display 4 is received between the optical waveguide 19 and the glass plate 2 by the position adjusting means integrally formed in the casing component member 5 on the front side. The glass plate 2, the liquid crystal display 4, and the optical waveguide 19 are put together by connecting the printed wiring board 20 to the casing component 5. The screw used for this purpose is designated by the reference numeral 21. A threaded stay with protrusions integrally molded into the casing component for this purpose is not visible in FIG. 2 but is not critical to the invention. Code 22
In, a reflector corresponding to the optical waveguide 19 is shown. Reference numeral 23 indicates an electrical connector provided between the printed wiring board 20 and the liquid crystal display 4.
Reference numeral 24 indicates a connector base which is contact-connected to the printed wiring board 20.
Are shown as an example of a number of electronic components arranged on opposite sides of the printed wiring board 20. Further in FIG.
One of the plurality of light emitting diodes 25 arranged in a row on the printed wiring board 20 is shown. Each light emitting diode 25 is integrally molded with the optical waveguide body 19,
It preferably projects into and engages a blind hole 26 with a spherically shaped hole bottom. With this arrangement, the optical waveguide 1
Light-insensitive coupling to 9 is guaranteed.
Further, as can be seen from FIG. 2, the control keys 7, 8, 9, 10
Is formed on a so-called switching mat 27, or a switching mat strip, which is manufactured from an elastic and electrically insulating material. That is, each control key 7, 8, 9, 10
It comprises a key shaft 28 and a collar 29 forming a transition to the switching mat 27. The brim 29 exerts a spring function having a snap effect. Each control key 7, 8,
9 and 10 are provided with contact plates 30, and when the control keys 7, 8, 9, and 10 are pushed down to the printed wiring board 20, the conductor path ends formed as contacts via the contact plates 30. 31 and 32 are short-circuited. The switching mat 27 is fixed directly through the optical waveguide 19 when fixing the printed wiring board 20. In this case, the optical waveguide 19
Formed webs or fingers 33, 34, 3
5, 36 act on the switching mat 27 and press it against the printed wiring board 20, advantageously in a point-like manner.
In this way, when the control keys 7, 8, 9 and 10 are operated, a certain degree of motility of the switching mat 27 can be obtained.

As is particularly clear from FIG. 3, which mainly shows the side of the optical waveguide 19 facing the printed wiring board 20,
It is extremely important that the guide paths 37, 38, 39, 40 corresponding to the key shaft portions 28 of the control keys 7, 8, 9, 10 are directly formed integrally with the optical waveguide 19. As a result, since the guide paths 37, 38, 39, 40 are filled with light rays, if the key shaft portion 28 is configured to be photoconductive,
The end surface of the key shaft portion 28 emits a light beam.

Eyes 41 and 42 are integrally formed on the optical waveguide body 19, and the optical waveguide body 19 is provided with the projections provided on the threaded stay corresponding to the screw 21 through the eyes 41 and 42. The printed wiring board 20 can be fastened and fixed by screwing. Slits 43 and 44 are shown, and these slits 43 and 44 serve to hold the two belt-shaped and electrically conductive connectors 23. The optical waveguide 19 is a multifunctional component. The wedge-shaped cross-section of this multifunctional component serves to illuminate the liquid crystal display 4 as uniformly as possible. In this case, a plurality of light emitting diodes 25 distributed over the entire length of the optical waveguide body 19 can be made to enter the optical waveguide body 19, so that good light incident coupling is provided. The optical waveguide 19 has means for accommodating the reflector 22, and the electrical connector 2
The slits 43 and 44 for holding 3 are processed and formed, and the optical waveguide 19 is further formed by the guide paths 37, 38, 39 and 40 which are directly formed integrally with the control keys 7, 8 and 9. , The control keys 7,
It also works to illuminate 8, 9, and 10. Due to the multi-functionality of the light guide 19, the number of components required is significantly reduced, and moreover, the given configuration space can be optimally utilized. That is, the size of the device can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a charge meter showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line A of FIG.

FIG. 3 is a perspective view of an optical waveguide.

[Explanation of symbols]

1 charge meter, 2 glass plate, 3 transparent range,
4 Liquid crystal display, 5,6 Casing constituent member, 7, 8, 9, 10 Control key, 11 Recognition display plate, 12 Cover, 13, 14 Recessed part, 15, 1
6 holes, 17 sealing body, 18 notch, 19 optical waveguide, 20 printed wiring board, 21 screw, 22
Reflector, 23 connector, 24 connector base, 25 light emitting diode, 26 blind hole, 27
Switching mat, 28 key shaft, 29 brim, 30
Contact plate, 31, 32 conductor path end, 33, 34,
35, 36 fingers, 37, 38, 39, 40 guideways, 41, 42 eyes, 43, 44 slits

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Holger Jeckle Germany Federal Republic of Monchweiler Sportplatz-Wake 5

Claims (6)

(57) [Claims] 1. A device for illuminating a control key of a charge meter, comprising a two-part casing, a printed wiring board supporting an electronic computer of the charge meter and a data memory, a liquid crystal display, An optical waveguide for illuminating the liquid crystal display from the rear side, a glass plate corresponding to the liquid crystal display on the front side, and a control key exposed on the front side and directly operable by hand are provided. In the type in which the contacts formed on the printed wiring board can be short-circuited, the key shaft portion (28) of the control key (7, 8, 9, 10) is made of a photoconductive material. In the optical waveguide (19),
Guideways (37, 38, 3) corresponding to the key shaft (28)
9.40) A device for illuminating the control key of a toll meter, characterized in that it is integrally molded. 2. The key shaft portion (28) is integrally formed with a strip-shaped switching mat (27), and the switching mat (27) is attached to a printed wiring board (20) by the optical waveguide (19). The optical waveguide (19) to be tightened
The device according to claim 1, characterized in that it corresponds to a printed wiring board (20). 3. The optical waveguide (19) is integrally molded with webs and fingers (33, 34, 35, 36) for tightening the switching mat (27) in a point manner. Equipment. 4. A device according to claim 1, wherein the optical waveguide (19) is connectable to the printed wiring board (20) by means of locking means. 5. An optical waveguide (19) when fixing a printed wiring board (20) to a front casing component (5).
The device of claim 1, wherein the device is operably connectable to the printed wiring board (20). 6. A blind hole (26) is formed in the optical waveguide (19), and a printed wiring board (2) is formed in the blind hole (26).
Device according to claim 1, characterized in that a light-emitting diode (25) arranged at 0) is plunged in.