Display device

Abstract

A display device comprising a liquid crystal display module having a liquid crystal cell (4) with a display region (15), a rear substrate (6) and a transparent front substrate (7), between which a liquid crystal substance is arranged, a pot-like housing (1) consisting of an electrically conductive sheet and having a surrounding frame (2) and a base (3), and an anti-reflective front panel (14) arranged parallel to the observer side in front of the liquid crystal display module, wherein the front panel (14) extends beyond the display region (15) of the liquid crystal cell (4) and, with the exception of a viewing window (16) in the display region (15) of the liquid crystal cell (4), is covered by an opaque layer (17), and wherein the liquid crystal cell (4) is inserted into the surrounding frame (2) in such a way thatthat the observer-side opening edge (8) of the frame (2) does not protrude beyond the observer-side plane (5) of the liquid crystal cell (4) towards the observer side.

Description

[0001] The invention relates to a display device with a liquid crystal display module having a liquid crystal cell with a display area, which has a rear and a transparent front substrate, between which a liquid crystal substance is arranged, wherein the liquid crystal cell is arranged in a surrounding frame and with an anti-reflective front panel arranged parallel to the liquid crystal display module on the observer side.

[0002] In such display devices, it is known that the observer-side opening edge of the frame encompasses the peripheral edge of the front substrate of the liquid crystal cell.

[0003] This creates a gap between the windscreen and the front substrate with a thickness corresponding to the material thickness of the frame. This gap is over one millimeter thick.

[0004] Due to the anti-reflective coating of the front panel, the blurring of the image of the liquid crystal cell seen by an observer increases with the increasing size of the gap between the front panel and the front substrate.

[0005] US 2010 / 0 202 077 A1 describes a flat panel display comprising a display module, a protective window element, and a layer disposed in a region between the protective window element and a display area of ​​the display module. The protective window element includes a stepped portion in which the layer is disposed.

[0006] EP 2 354 835 A1 describes a liquid crystal display comprising a liquid crystal display panel and a front surface plate on the display side of the liquid crystal display panel, the front surface plate having a first portion, a second portion and a third portion.

[0007] DE 197 58 383 A1 describes a display unit for a motor vehicle in which an LCD display is arranged in a plane with the dial of a pointer instrument. For this purpose, the dial has a recess into which the display is glued.

[0008] The object of the invention is to provide a display device of the type mentioned at the outset, by means of which the display of the liquid crystal cell can be clearly perceived by an observer.

[0009] This object is achieved according to the invention in that the front panel extends beyond the display area of ​​the liquid crystal cell and is covered by an opaque layer with the exception of a viewing window in the display area of ​​the liquid crystal cell, wherein a housing consisting of an electrically conductive sheet is pot-shaped with a base and a surrounding frame into which the liquid crystal cell is inserted in such a way that the observer-side opening edge of the frame does not protrude beyond the observer-side plane of the liquid crystal cell towards the observer side.

[0010] The viewing window and the opaque area provide a high-contrast demarcation of the liquid crystal cell's display area. Areas adjacent to the display area and the liquid crystal cell do not interfere with the capturing of the liquid crystal cell's images.

[0011] Since the frame of the housing does not protrude above the observer-side plane of the liquid crystal cell, the front panel can be positioned close to the front substrate of the liquid crystal cell, so that there is no blurring of the image of the liquid crystal cell for an observer.

[0012] Furthermore, beyond the circumferential contour of the liquid crystal cell, no space is required other than the material thickness of the frame, so that the space requirement of the display device can be kept low.

[0013] The overall thickness of the display device is also reduced.

[0014] This is particularly advantageous when the display device is used in a motor vehicle, and in particular in a combination instrument, since additional displays and display components can be arranged close to the liquid crystal cell.

[0015] Preferably, the front glass is float glass with a thickness of the order of 1 mm.

[0016] The front panel can be arranged at a distance of < 0.8 mm, in particular between 0.2 mm and 0.6 mm and preferably at a distance of 0.4 mm from the observer-side plane of the liquid crystal cell.

[0017] The front panel and liquid crystal cell can be arranged without any direct connection to each other.

[0018] In order to further increase the sharpness of the display of the liquid crystal cell, the gap formed between the front panel and the front substrate of the liquid crystal cell can be filled with a transparent material whose refractive index corresponds to the refractive index of the front panel and / or the front substrate, so that no refraction of light occurs between the display plane of the liquid crystal cell and the observer-side plane of the front panel.

[0019] A component unit which can be easily preassembled is achieved by arranging a printed circuit board with electrical and electronic components and / or an illumination device for transmissive illumination of the liquid crystal cell in the housing between its base and the liquid crystal cell.

[0020] The housing can have a dual function as a shielding housing against electromagnetic radiation.

[0021] For this purpose, it is possible to design the housing as a sheet metal housing made of an electrically conductive material.

[0022] However, it is also possible that the housing is made of an electrically non-conductive material such as a plastic and, in particular, is provided with a coating of an electrically conductive material on its inside.

[0023] The bottom of the housing is preferably at least largely closed.

[0024] The shielding housing is connected to ground via one or more connecting lines.

[0025] Also in a dual function, the opaque layer of the windscreen can be an electrically conductive layer and the connecting lines can be connected to the electrically conductive layer.

[0026] This also makes it possible to keep the connecting lines short.

[0027] For easy assembly, the connecting cables can be conductive foils, in particular conductive adhesive foils.

[0028] If the display device is to be combined with further components, in particular further display elements, the liquid crystal display module with its housing can be inserted into a receptacle of a carrier component.

[0029] For this purpose, the holder is preferably designed in a pot-like manner and the liquid crystal cell is fastened with its edge region extending over the display area on the front edge of the opening of the holder and to the holder.

[0030] Embodiments of the invention are illustrated in the drawings and are described in more detail below. Fig. 1: a schematic diagram of a display device, Fig. 2: a front view of an embodiment of a display device, Fig. 3: a section along the line I - I in Fig. 2, Fig. 4: a rear view of the display device according to Fig. 2, Fig. 5: an enlarged section “X” from Fig. 3, Fig. 6: a section along the line II -II from Fig. 2, Fig. 7: an enlarged section “Y” from Fig. 6.

[0031] The display devices shown in the figures have a pot-shaped housing 1 which consists of an electrically conductive sheet and has a surrounding frame 2 and a base 3.

[0032] On the observer side, a liquid crystal cell 4 is arranged on the housing 1 in such a way that the frame 2 of the housing 1 does not protrude beyond the observer-side plane 5 of the liquid crystal cell 4 towards the observer side.

[0033] Housing 1 and liquid crystal cell 4 together form a liquid crystal display module 13.

[0034] The liquid crystal cell 4 consists of a transparent rear substrate 6 and a transparent front substrate 7, which carry transparent electrodes (not shown) on their mutually facing sides. A liquid crystal substance is arranged between the substrates 6 and 7.

[0035] In the embodiment of the Fig. 1, the housing 1 is arranged with the opening edge 8 of the frame 2 abutting the surface of the rear substrate 6 in such a way that the peripheral edge region 9 of the liquid crystal cell 4 projects radially beyond the frame 2.

[0036] This edge region 9 is glued to a front edge 10 of an opening of a cup-shaped receptacle 11 of a support component 12. The liquid crystal display module 13 is thus attached to the support component 12.

[0037] In the Fig. 2 to 7, the liquid crystal cell 4 is inserted into the frame 2 such that the frame 2 does not protrude beyond the observer-side plane 5 of the liquid crystal cell 4.

[0038] On the observer side in front of the liquid crystal cell 4, a front panel 14 is arranged parallel to its front substrate 7, which extends beyond the display area 15 of the liquid crystal cell 4.

[0039] The gap 18 between the liquid crystal cell 4 and the front glass 14 is filled with a transparent material whose refractive index corresponds to the refractive index of the front glass 14.

[0040] The front panel 14 consists of a float glass with a thickness of approximately 1.0 mm and is covered on its side facing away from the observer with an opaque layer 17 made of a carbon print, with the exception of a viewing window 16 corresponding to the display area 15.

[0041] On the observer side, the front screen 14 is provided with an anti-reflective structure, e.g. by etching, which at least largely prevents light reflections.

[0042] The housing 1 is connected to the mass-forming layer 17 by electrically conductive adhesive films 19.

[0043] Thus, the housing 1 is a shielding housing which shields against electromagnetic radiation emanating from a lighting device (not shown) and circuits and electrical and electronic components arranged on a printed circuit board.

[0044] The lighting device and the circuit board are arranged in the housing between its bottom 3 and the liquid crystal cell 4 but are not shown. List of reference symbols 1 housing 2 frames 3 Floor 4 liquid crystal cell 5 observer-side level 6 back substrate 7 front substrate 8 Opening edge 9 Marginal area 10 Rand 11 Recording 12 Support component 13 Liquid crystal display module 14 Windscreen 15 Display area 16 viewing windows 17 shift 18 gap 19 adhesive film

Claims

[1] Display device with a liquid crystal display module, which has a liquid crystal cell (4) with a display area (15), which has a rear substrate (6) and a transparent front substrate (7), between which a liquid crystal substance is arranged, a pot-like housing (1) consisting of an electrically conductive sheet and having a surrounding frame (2) and a base (3), and an anti-reflective front panel (14) arranged parallel to the observer side in front of the liquid crystal display module, wherein the front panel (14) extends beyond the display area (15) of the liquid crystal cell (4) and, with the exception of a viewing window (16) in the display area (15) of the liquid crystal cell (4), is covered by an opaque layer (17), and wherein the liquid crystal cell (4) is inserted into the surrounding frame (2) in such a way thatthat the observer-side opening edge (8) of the frame (2) does not protrude beyond the observer-side plane (5) of the liquid crystal cell (4) towards the observer side. [2] Display device according to claim 1, wherein the front panel (14) is arranged at a distance of < 0.8 mm from the observer-side plane (5) of the liquid crystal cell (4). [3] Display device according to claim 2, wherein the front panel (14) is arranged at a distance of between 0.2 mm and 0.6 mm from the observer-side plane (5) of the liquid crystal cell (4). [4] Display device according to one of claims 2 and 3, wherein the gap (18) formed between the front panel (14) and the front substrate (7) of the liquid crystal cell (4) is filled with a transparent material whose refractive index corresponds to the refractive index of the front panel (14) and / or the front substrate (7). [5] Display device according to one of the preceding claims, wherein a printed circuit board with electrical and electronic components and / or an illumination device for transmissive illumination of the liquid crystal cell (4) are arranged in the housing (1) between its base (3) and the liquid crystal cell (4). [6] Display device according to one of the preceding claims, wherein the housing (1) is a shielding housing against electromagnetic radiation. [7] Display device according to claim 6, wherein the shielding housing is connected to ground via one or more connecting lines (19). [8] Display device according to claim 7, wherein the opaque layer (17) of the front panel (14) is an electrically conductive layer and the connecting lines (19) are connected to the electrically conductive layer (17). [9] Display device according to one of the preceding claims, wherein the liquid crystal display module (13) is inserted with its housing (1) into a receptacle (11) of a carrier component (12). [10] Display device according to claim 9, wherein the receptacle (11) is pot-shaped and the liquid crystal cell (4) is fastened with its edge region (9) extending over the display region (15) on the front edge (10) of the opening of the receptacle (11) in support and to the receptacle (11).

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