EP0971259A1 - Backlight device for liquid crystal display - Google Patents

Abstract

The arrangement has an LED field, the mechanical coupling dimensions and the electrical connection parameters of the existing lighting arrangement is coupled to an electronic adapter circuit (3) and used in place of the existing lighting arrangement. The arrangement can have the mechanical an electrical connections of a conventional fluorescent lamp and carries the adapter circuit on its rear for connection via electrical contact pins (4) to a conventional fluorescent lamp holder.

Description

The invention relates to an arrangement for backlighting LCD displays (liquid crystal display) using LED (light-emitting Diode), especially in public information systems Passenger transport.

In public transport information systems such as Bus, tram, railroad, shipping and plane become current information display LCD displays used for Brightening are backlit by means of fluorescent lamps.

The fluorescent lamps have a relatively short lifespan, so that their failure or their unreliable before the failure Ignition or the blackening of the fluorescent lamp ends often leads to display quality problems.

There are already backlights from LCD displays in the form of large-area LED blocks known, but with fluorescent lamps equipped displays only with great effort when converting of electrical systems can be used.

The object of the invention is an arrangement for backlighting of LCD displays using LED to develop with the existing one Displays backlit with illuminants such as fluorescent lamps can be retrofitted without converting existing electrical systems can.

The solution to the problem results from the features of the claim 1. Then an LED field with the mechanical connection dimensions and the electrical connection values of the previously used Illuminant together with an electronic adjustment circuit to replace the previous illuminant in existing ones electrical connection devices used.

It becomes a problem with the arrangement according to the invention Exchange of fluorescent lamps with a relatively short lifespan through an LED field without modification of existing electrics, especially the existing ballasts, and thereby ensures a more reliable backlighting of LCD displays. The LCD display will be evenly illuminated due to the parallel arrangement of an LED field for backlighting reached. Reflectors and a special paint internal surfaces can be saved.

Advantageous designs of the arrangement result from the subclaims.

Fig. 1 :

die schematische Rückansicht der Anpaßelektronik und

Fig. 2 :

die schematische Seitenansicht eines LED-Feldes mit der Anpaßelektronik nach Fig. 1.

The invention is explained in more detail in an exemplary embodiment with reference to a drawing. Show it:

Fig. 1:

the schematic rear view of the adapter electronics and

Fig. 2:

the schematic side view of an LED field with the adapter electronics of FIG. 1st

Fig. 1 shows the rear view of an adapter electronics 3, which is provided with contact pins 4, which in the existing Snap the sockets of the fluorescent lamp (not shown) and there contact electrically so that existing fluorescent lamps can be easily exchanged for an LED field 1 (Fig. 2) can. The LED field 1 is connected to the adapter electronics 3 in such a way that when plugged together into the existing electrical Connections all over and parallel behind the one to be backlit LCD display (not shown) is arranged.

According to the representation in FIG. 2, the LED field 1 from light-emitting diodes arranged across the entire field 2, in particular yellow LED 2, formed, the dimensions of LED field 1 in adaptation to the one to be backlit LCD display are selected.

The electrical pins 4 of the adapter electronics 3 are optionally Arranged rotated by 90 ° when it is in the installation position the original fluorescent lamp required makes.

The one arranged on the back of the flat, block-shaped LED field 1 Matching electronics 3 is used to adapt to the existing Voltages and connection values of the originally available Fluorescent lamp.

The LEDs 2 are yellow in color to match the LCD display selected and operated in one operating point, which represents an optimum between the lifespan and the brightness.

The dimensions width and length of the LED field 1 are the LCD display area so precisely adjusted that the LCD display area evenly illuminated in the corners.

The invention is not limited to that shown here Embodiment. Rather, it is possible through combination and modification of the means and features mentioned further variants to realize without the scope of the invention to leave.

Reference list

1

LED field

2nd

led

3rd

Matching electronics

4th

Contact pin

Claims (5)

Arrangement for backlighting LCD displays using LEDs,
characterized,
that an LED field (1) with the mechanical connection dimensions and the electrical connection values of the previously used illuminant is coupled to an electronic adaptation circuit (3) and used instead of the previous illuminant. Arrangement according to claim 1,
characterized,
that the LED field (1) with the mechanical connection dimensions and the electrical connection values of a previously used fluorescent lamp is flat and block-shaped and has on the back the electronic adaptation circuit (3), which via electrical contact pins (4) in the version of the previously used Fluorescent lamp is introduced. Arrangement according to claims 1 and 2,
characterized,
that the color of the light emitting diodes (2) of the LED field (1) is adapted to the color of the LCD display. Arrangement according to claims 1 to 3,
characterized,
that the dimensions of the LED field (1) are exactly adapted to the dimensions of the LCD display area. Arrangement according to claims 1 to 4,
characterized,
that the light-emitting diodes (2) of the LED field (1) are operated at an operating point which represents an optimum between the brightness and the service life.

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