DEVICE FOR DISPLAYING INFORMATION, IN PARTICULAR FOR A VEHICLE

Abstract

The device for displaying information, in particular for a vehicle, is provided with a display unit having a plurality of pixels and having a front side forming the display surface for displaying information and a rear side facing away from the front side. Furthermore, the device comprises a backlighting unit for emitting backlight towards the rear side of the display unit for backlighting the same, and an adjustable transreflective layer between the backlighting unit and the display unit. The adjustable transreflective layer has an array of segments, each of which is controllable by means of an electric control signal to adjust the degree of transmission and/or reflection and is thus dimmable. The contrast of information shown on the display surface can be adjusted by dimming, as a result of controlling the segments, those pixels of the display unit which are arranged in alignment with the segment or segments concerned and are assigned to the same.

Claims

1. A device for displaying information, comprising a display unit having a plurality of pixels, the display unit having a front side forming the display surface for displaying information and a rear side facing away from the front side, a backlighting unit for emitting backlight towards the rear side of the display unit for backlighting the same, and an adjustable transreflective layer between the backlighting unit and the display unit for transmitting backlight to backlight the display unit and/or for reflecting backlight to the backlighting unit, the adjustable transreflective layer having an array of segments, each of which is controllable by means of an electric control signal to adjust the degree of transmission and/or reflection and is thus dimmable, and wherein the contrast of information shown on the display surface (44) can be adjusted by dimming, as a result of controlling the segments of, those pixels of the display unit which are arranged in alignment with the segment or segments concerned and are assigned to the same.

2. The device according to claim 1, wherein the controllable transreflective layer has a liquid crystal mirror layer or an electrochromic or electrochemical mirror layer.

3. The device according to claim 1, wherein the backlighting unit comprises an array of reflectors and a plurality of light sources, wherein at least one light source is assigned to each reflector, and wherein at least one segment of the adjustable transreflective layer and preferably more than one segment, for example two to ten segments of the adjustable transreflective layer are arranged in alignment with each reflector.

4. The device according to claim 1, wherein the backlighting unit comprises a plurality of light sources and a light guide plate having two main surfaces and a side surface therebetween, one of the two main surfaces facing the back of the display unit and being provided for emitting light entering the light sources from the side surface or light entering the light sources from the other main surface.

5. The device according to claim 1, wherein the light sources are designed as LEDs or laser diodes.

6. The device according to claim 1, further comprising a touch panel for touch sensitivity assigned to the display surface, or a touch panel that is part of the display unit and is provided for assigning touch sensitivity to the display surface.

7. The device according to claim 1, wherein the display unit is designed as an LCD display unit.

Description

[0021] FIG. 1 is a schematic view of the main components of an exemplary embodiment of an electronic device for displaying information according to the invention,

[0022] FIG. 2 is a perspective and partially broken-down view of the backlighting unit with individual reflectors and a diffuser arranged above them, as well as a controllable LC mirror layer above the diffuser with groups of four segments assigned to the individual reflectors in this embodiment,

[0023] FIG. 3 is a plan view of the LC mirror layer (partially), and

[0024] FIG. 4 is a schematic illustration of the different operating states in which the controllable LC mirror layer can be operated.

[0025] FIG. 1 is a schematic illustration of the main components of a device 10 for displaying graphic and/or alphanumeric information according to the invention. A component of said device 10 is a display unit 12, which in this exemplary embodiment is an LCD 14 (liquid crystal display). The front side 16 of the display device 12 forms the display surface 18, wherein in this illustration, the cover glass typically found on LCDs and the optical connection have been omitted. The display unit 12 can additionally be provided with a touch sensor system, which is also not shown in the schematic illustration of FIG. 1.

[0026] Below the display unit 12 is a backlighting unit 20, which will be discussed further below.

[0027] Between the backlighting unit 20 and the rear side 22 of the display unit 12 is a controllable transreflective layer 24, which in this exemplary embodiment is designed as an electronically controllable and thus adjustable LC mirror layer 26 (liquid crystal mirror layer) or as a reversible electrochromic or electrochemical mirror layer (REM mirror layer).

[0028] Referring to FIG. 4, it is clear how the transreflective LC layer 26 can be operated. By electronically driving the transreflective LC mirror layer 26, it can be operated in a substantially purely transmissive state (see the left illustration of FIG. 4), a substantially purely reflective state (see the right illustration of FIG. 4), and an intermediate state, i.e., transreflective (see the middle illustration of FIG. 4). The degree of reflection and transmission can be adjusted electronically. This technology is generally known. The degree of absorption in both transmission and reflection is so small that it can be ignored in this respect.

[0029] New in the context of the invention is the use of such an LC mirror layer 26 for local dimming of the pixels of an LCD. According to the invention, the local dimming of the transilluminance with which the pixels of an LCD are transilluminated is performed using the transreflective LC mirror layer 26. For this purpose, the LC mirror layer 26 is divided into individual surface area, the so-called segments 28. The transreflective LC mirror layer 26 can now be controlled on a segment-by-segment basis so that the degree of reflection or transmission can be adjusted differently on a segment-by-segment basis.

[0030] FIG. 2 shows a possible structure of the backlighting unit 20, which comprises a reflector array 30 of individual reflectors 32, each reflector being assigned one or more light sources 34. In this exemplary embodiment, the light sources 34 are designed as LEDs or laser diodes and are located on a circuit board 36, for example. On this circuit board 36 is the reflector array 30, above which is typically a diffuser 38 for light equalization (light homogenization). The transreflective LC mirror layer 26 is then arranged above said diffuser 38.

[0031] An advantage of the device according to the invention will be explained below with reference to FIG. 2. It is assumed that of the four segments 28 assigned to a reflector 32 in this exemplary embodiment, one segment is to provide dimming of the transillumination of the pixels of the LCD 14 assigned to said segment. This segment is shown hatched in FIG. 2. The light from the light source 34 hitting this segment is now reflected more than the light hitting the other segments associated to the reflector 32. The reflected light is reflected back through the reflector 32 to the less dimmed segments or to the segments that are not dimmed at all, contributing to an increase in the strength of the light that transilluminates the pixels assigned to said segments. This increase in luminous intensity in turn leads to an increased contrast by increasing the “luminous efficiency” of the pixels that require less or no dimming. Overall, the invention can enhance the contrast effect, i.e., the visual light-dark appearance, which in turn means that an increased level of contrast can be achieved by local dimming with less energy input.

LIST OF REFERENCE NUMERALS

[0032] 10 device [0033] 12 display unit [0034] 14 LCD [0035] 16 front side [0036] 18 display surface [0037] 20 backlighting unit [0038] 22 rear side of display unit [0039] 24 controllable transreflective layer [0040] 26 LC reflective layer [0041] 28 segments [0042] 30 reflector array [0043] 32 reflectors [0044] 34 light source [0045] 36 circuit board [0046] 38 diffuser