Dustproof and waterproof display and method for mounting a dustproof and waterproof display

Abstract

Display (100; 100'), comprising a cover glass (1), a liquid crystal panel (12) of a flexible printed circuit board (5), with a first free end (5a), a second free end (5b) and a section (5c) equipped with electrical and / or electronic components (14) between the first and second free ends (5a, 5b), a backlight unit (11) and a display housing (9), wherein the section (5c) of the flexible printed circuit board (5) equipped with the components (14) is arranged outside the display housing (9) and the first free end (5a) of the flexible printed circuit board (5) is connected to the liquid crystal panel (12) and the flexible printed circuit board (5) is connected to the cover glass (1) and the display housing (9) in a region between the first free end (5a) and the section (5c) equipped with the components (14).

Description

[0001] The invention relates to a display with a cover glass, a liquid crystal panel, a flexible circuit board, with a first free end, a second free end and a section equipped with electrical and / or electronic components between the first and the second free end, a backlight unit and a display housing, wherein the section of the flexible circuit board equipped with the components is arranged outside the display housing and the first free end of the flexible circuit board is connected to the liquid crystal panel and the flexible circuit board is connected to the cover glass and the display housing in a region between the first free end and the section equipped with the components. State of the art

[0002] In currently known displays, a flexible circuit board with a first free end is first connected to a liquid crystal panel and then inserted into a display housing. The flexible circuit board with a second free end is then led out of the display housing through an opening in the display housing and onto the outside of the display housing, where it is connected to a main circuit board. The opening must be large enough to allow the flexible circuit board populated with components to pass through. During this assembly step, one or more of the components may be damaged. In addition, the opening must be subsequently sealed dust- and / or watertight in an additional assembly step with an additional component, e.g. adhesive tape, to prevent dust and moisture from penetrating the interior of the display housing.If the display housing is connected to the cover glass, for example, by adhesive bonding, there is also a risk that the flexible circuit board will come into contact with the adhesive during assembly. A prior art display is shown in Figure A and marked as prior art. The reference numerals in Figure A correspond to the reference numerals of the . Fig. 1 to 3. Disclosure of the invention

[0003] There is a need for a display that is easy to assemble and connects the display housing to the cover glass in a dust- and watertight manner. Furthermore, there is a need for a method for assembling such a display.

[0004] The object is to provide an easy-to-assemble display in which the display housing is sealed against the environment in a dust- and / or water-tight manner, as well as to provide a method for assembling such a display.

[0005] This object is achieved by the subject matter having the features of claim 1 and the method having the method steps of claim 8.

[0006] One aspect relates to a display with a cover glass, a liquid crystal panel, also referred to here and below as “liquid crystal panel”, a flexible printed circuit board with a first free end, a second free end and a section equipped with electrical and / or electronic components between the first and the second free end, a backlight unit, also referred to here and below as “backlight unit”, and a display housing, wherein the section of the flexible printed circuit board equipped with the components is arranged outside the display housing and the first free end of the flexible printed circuit board is connected to the liquid crystal panel and the flexible printed circuit board is connected to the cover glass and the display housing in a region between the first free end and the section equipped with the components.

[0007] The cover glass is bonded to the liquid crystal panel. The adhesive used can be a conventional optical adhesive, i.e., one suitable for optical applications. The first free end of the flexible circuit board can be bonded to the display housing using an adhesive layer, for example, a work-on adhesive. This adhesive layer can be the same adhesive used to bond the display housing to the cover glass during assembly. The work-on adhesive can be applied to the display housing shortly before an assembly step in which the display housing is bonded to the cover glass, or the already applied adhesive can be activated for assembly, for example, by heat or light.

[0008] The first free end of the flexible circuit board can extend parallel to the cover glass up to the liquid crystal panel. The flexible circuit board can rest on an upper side of the display housing facing the cover glass, or the display housing includes an opening for the flexible circuit board. The opening in the display housing can be a groove-shaped depression in an end face of the display housing facing the cover glass, with a width that essentially corresponds to a width of the flexible circuit board in the region of the first free end or a first free end section parallel to the cover glass, and a depth perpendicular to the cover glass that essentially corresponds to a thickness of the flexible circuit board in this region. The opening in the display housing can be formed opposite the liquid crystal panel where the liquid crystal panel is connected to the first free end of the flexible circuit board, for example by a plug connection.

[0009] To ensure a dust- and / or watertight seal around the opening in the display housing, an adhesive layer, such as double-sided adhesive tape, can be placed between the cover glass and the flexible circuit board. This adhesive layer can seal the interior of the display housing from the environment around the opening, preventing the ingress of dust and moisture. The adhesive layer can reliably seal the opening above and on both sides adjacent to the first free end of the flexible circuit board.

[0010] The sealed display can be used for any display product that requires dust and / or water protection. Such display products can be used in vehicles, for example.

[0011] The flexible printed circuit board can have a reinforcement or stiffener in the section populated with the components. This reinforcement or stiffener can extend in the longitudinal direction of the flexible printed circuit board on one or both sides beyond the section populated with the components. The reinforcement or stiffener can be firmly connected to the flexible printed circuit board only in the section containing the components. The stiffener and / or the extension(s) can form support surfaces that, for example, abut against the display housing to fix the flexible printed circuit board and are joined, for example, detachably joined, to the display housing.

[0012] The display housing can have a profile edge extending away from the cover glass with an upper side running parallel to a plane spanned by the cover glass and an outer side extending perpendicular thereto away from the cover glass, wherein the upper side has an opening which is covered by the section of the flexible printed circuit board with the components, so that the components lie outside the display housing within the profile edge.

[0013] In one embodiment, the display can be connected to a main circuit board and a rear cover, with the rear cover having a resealable access opening and the flexible circuit board located beneath the access opening. The access opening can be closed with a plastic part that is connected to the rear cover via a pivot joint, or can be plugged onto the rear cover, for example, or slid onto it using the tongue-and-groove principle and secured against accidental release. The plastic part can extend below the cover glass.

[0014] The flexible circuit board that connects the liquid crystal panel to a main circuit board is located outside the display housing except for the first free end. This means that the flexible circuit board with the component section lies in a cavity formed between the display housing and the back cover.

[0015] A further aspect relates to a method for assembling or mounting a display, in which in a first method step a cover glass is connected to a liquid crystal panel and provided, in a second method step a display housing with a backlight unit is provided, in a third method step a first free end of a flexible circuit board is connected to the liquid crystal panel and fastened to the cover glass by adhesion, in a fourth method step an adhesion layer is applied and / or activated in a region of the display housing in which the first free end of the flexible circuit board emerges from the display housing, in a fifth method step the combination of cover glass and liquid crystal panel is connected to the display housing and thereby the first free end of the flexible circuit board is fixed between the cover glass and the display housing.

[0016] The first free end of the flexible circuit board can be guided parallel to a surface of the cover glass during assembly of the display housing and cover glass. This means that the flexible circuit board, or its first free end, runs essentially parallel to the cover glass from the connection to the liquid crystal panel to at least the outside of the display housing.

[0017] In one embodiment of the display with a display housing with a profile edge, the flexible circuit board, including a section that is equipped with electrical and / or electronic components, can run essentially parallel to the cover glass. The flexible circuit board can have a reinforcement or stiffener that is firmly connected to the flexible circuit board in the section with the components. The reinforcement or stiffener can extend in the longitudinal direction of the flexible circuit board beyond the section with the components, wherein the regions of the stiffener extending beyond the section with the components cannot be connected to the flexible circuit board, but can form a support surface with which the stiffener can rest on the display housing, for example, and be connected to the display housing.The components can protrude downwards from the flexible circuit board and are located inside the edge and outside the display housing.

[0018] All features described in connection with the display can, where appropriate, also be read into the procedure, and vice versa.

[0019] The display's design enables, among other things, a simplified assembly process, simple and repeatable positioning of the flexible circuit board without complex positioning, protection of the electrical components from electrostatic discharge, a reduction in the length of the flexible circuit board and its cable length, and no complex bending of the flexible circuit board. Assembly time can be shortened, thus further reducing costs.

[0020] Further advantages are that the flexible circuit board can be joined directly to the cover glass and display housing using existing adhesive bonds, thus sealing the through-hole in the display housing for the first free end of the flexible circuit board to make it dust and watertight. The section of the flexible circuit board containing the electrical and / or electronic components lies outside the display housing and therefore does not need to be sealed accordingly. The adhesive tape that is already present for connecting the cover glass to the display housing is used to fix the flexible circuit board to the cover glass before assembly. The early frictional connection between the cover glass and the flexible circuit board reduces the risk of voltages being transferred into the liquid crystal panel through the flexible circuit board. The section of the flexible circuit board containing the components outside the display housing can be assembled and fixed from the front.The stiffening of the flexible circuit board is used to fix the section with the components to the display housing using existing adhesive connections.

[0021] Exemplary embodiments of a display and a method for assembling a display are explained in more detail using the figures. The figures show in detail: Figure A: State of the art; Fig. 1: a display with a sealed display housing and back cover with a resealable opening; Fig. 2: a display with a sealed display housing with a profile edge; Fig. 3: a display of the Fig. 2 shortly before assembly; Fig. 4: a block sketch procedure.

[0022] The Fig. 1 shows a first embodiment of a display 100. The display 100 comprises a cover glass 1 and a liquid crystal panel 12 connected to the cover glass 1. The connection can be an adhesive bond using an optical, i.e., transparent, adhesive 13. The display 100 further comprises a backlight unit 11 and a display housing 9, which accommodates the backlight unit 11 and is connected, for example, glued, to a surface 1a of the cover glass 1 facing the liquid crystal panel 12.

[0023] The display 100 further comprises a main circuit board 8, which is connected to the backlight unit 11 via a connector 6, such as a B2B connector, and a rear cover 7, which encloses the main circuit board 8 and the display housing 9. The rear cover 7 comprises a plastic part 3, which forms a resealable cover for an opening 7a through which the interior of the rear cover 7 is accessible.

[0024] The display 100 further comprises a flexible circuit board 5 having a first free end 5a, a second free end 5b, and at least one section 5c equipped with electrical and / or electronic components 14. The first free end 5a of the flexible circuit board 5 is connected to the liquid crystal panel 12, and the second free end 5b is connected to the main circuit board 8. This means that the flexible circuit board 5 connects the main circuit board 8 to the liquid crystal panel 12. The section 5c of the flexible circuit board 5 with the components 14 lies outside the display housing 9 and inside the rear cover 7. In the sectional view of the display 100 shown, the section 5c with the components 14 lies next to or in front of the cover glass 1.

[0025] To connect the first free end 5a of the flexible circuit board 5 to the liquid crystal panel 12, the first free end 5a runs essentially parallel to the surface 1a of the cover glass 1 through a passage or opening 9a of the display housing 9. Opening 9a also includes the display housing 5, in the region of the passage of the flexible circuit board, merely forming a support for the flexible circuit board 5. The display housing 9 has a further opening 9b for the connector 6, which connects the main circuit board 8 to the backlight unit 11.

[0026] To prevent moisture and dirt from entering the interior of the display housing 9 through the opening 9a, the first free end 5a of the flexible circuit board 5 is sealed both to the surface 1a of the cover glass 1 and to the support surface in the opening 9a. This sealing can be achieved using an adhesive, an adhesive tape 2, preferably a double-sided adhesive tape, or similar means. The side edges of the flexible circuit board 5 (not shown), which run parallel to the image plane, are also sealed accordingly. This means that the cover glass 1 is firmly bonded to the display housing 9, and the interior of the display housing 9 is protected from dust and moisture / water.

[0027] A heat-conducting band or heat-conducting tape 10 is arranged between the backlight unit 11 and the display housing 9. The heat-conducting tape 10 ensures, among other things, that no dust or water can penetrate into the display housing 9 through the opening 9b for the connector 6.

[0028] In the exemplary embodiment, the display housing 9 forms a support 9c for the flexible printed circuit board 5, or rather, the section 5c of the flexible printed circuit board 5 with the electrical and / or electronic components 14. The section 5c can simply rest on the support 9c or be connected to the support 9c mechanically or by an adhesive layer 4. The flexible printed circuit board 5 can have an additional reinforcement or stiffening 17 in the section 5c with the components 14.

[0029] During assembly of the display 100, the flexible circuit board 5 can first be connected to the cover glass 1 at the surface 1a with its first free end 5a. The cover glass 1 is then connected to the liquid crystal panel 12 and the connected flexible circuit board with the display housing 9, so that the flexible circuit board 5, except for the first free end 5a, lies outside the display housing 9 and inside the rear cover 7. The second free end 5b of the flexible circuit board 5 can now be conveniently connected to the main circuit board 8 through the opening 7a. The opening 7a can then be closed with the plastic part 3. The opening 7a also makes it possible for the flexible circuit board 5 to be mounted at the very end of the assembly of the display 100. The opening 7a also enables easy replacement of a defective flexible circuit board 5.

[0030] Since the interior of the rear cover 7 is not sealed against dust and moisture, the support 9c for the section 5c of the flexible printed circuit board 5 in the exemplary embodiment forms a collecting and guiding structure 9d, which collects penetrating water and / or condensation and guides it, for example, out of the rear cover 7. As shown in the Fig. As can be seen in Figure 1, the plastic part 3 engages under the cover glass 1 when closed, for example to prevent water from running from the cover glass 1 into the rear cover 7. The plastic part 3 must therefore be pushed over the opening 7a in the direction of the arrow or pushed or pivoted under the cover glass 1 in a pivot joint (not shown) in which the plastic part 3 is connected to the rear cover 7. Once the opening 7a is closed with the plastic part 3, it is secured against accidental opening by known means, for example, by means of a clip.

[0031] The Fig. 2 shows a further embodiment of a display 100', which has essentially the same structure as the display 100 of the Fig. 1. Accordingly, identical parts are provided with identical reference symbols.

[0032] The display 100' of the Fig. 2 differs from the display 100 of the Fig. 1, particularly in the design of the display housing 9'. The display 100' comprises a cover glass 1, which is connected to a liquid crystal panel 12 by an optical adhesive 13, the display housing 9' with a backlight unit 11, and a heat-conducting tape 10. The display 100' further comprises a main circuit board 8, which is connected to the backlight unit 11 via a connector 6. The display housing 9' essentially corresponds to the display housing 9 of Fig. 1, with a passage or opening 9a for the first free end 5a of the flexible circuit board 5 and an opening 9b for the connector 6. Finally, the display 100' comprises a rear cover 7.

[0033] The display housing 9' of the Fig. 2, however, does not include a support 9c for the section 5c of the flexible printed circuit board 5 with the electrical or electronic components 14, which is formed by the display housing 9' and arranged in the space between the display housing 9' and the rear cover 7. Instead, the display housing 9' includes, at least in or adjacent to the area of ​​the opening 9a', an edge 16 or profile edge with a first arm 16a, which initially runs outwards parallel to the cover glass 1, and a second arm 16b, which bends downwards at a right angle from the first arm 16a, away from the cover glass 1 in the direction of the rear cover 7, and is connected by its free end to an end face 7b of the rear cover 7 facing the cover glass 1.

[0034] The flexible printed circuit board 5 comprises a first free end 5a, which is connected to the liquid crystal panel 12, a second free end 5b, which is connected to the main printed circuit board 8, and a section 5c, which is arranged between the first free end 5a and the second free end 5b. The section 5c is equipped with electrical or electronic components 14. The flexible printed circuit board 5 further comprises a reinforcement or stiffener 17 in the region of the section 5c, which is firmly connected to the flexible printed circuit board 5 at least in the region of the section 5c that is equipped with the components 14. In the exemplary embodiment, the stiffener 17 extends in the longitudinal direction L of the flexible printed circuit board 5 on both sides beyond the section 5c, wherein the projecting ends 17a, 17b of the stiffener 17 are not connected to the flexible printed circuit board 5. The protruding ends 17a, 17b are connected to the display housing 9' and 17' respectively.firmly connected to the edge 16, in the exemplary embodiment in an adhesive connection 4. As for . Fig. 1, the opening 9a is sealed dust- and watertight with a double-sided adhesive tape 2.

[0035] The projecting end 17b of the stiffener 17 rests on the second arm 16b of the edge 16 and is firmly connected thereto, in the exemplary embodiment, adhered with a double-sided adhesive tape 2. By supporting the stiffener 17 at both projecting ends 17a, 17b, the section 5c' of the flexible printed circuit board 5' with the electrical and / or electronic components 14 is firmly anchored and well protected against damage. The flexible printed circuit board 5' is easily accessible and can thus be easily replaced or conveniently installed after assembly of the display 100'.

[0036] The Fig. 3 in conjunction with the Fig. 4 describes a method for assembling a display, for example a display 100 of the Fig. 1 or a display 100' of Fig. 2. The Fig. 3 shows the assembly process shortly before the end of the assembly of the display 100'.

[0037] In a first method step I, the cover glass 1 is connected to the liquid crystal panel 12, for example in a clean room, and prepared. In a second method step II, the display housing 9' with the backlight unit 11 is prepared. In a third method step III, a first free end 5a of the flexible circuit board 5 is connected to the liquid crystal panel 12 and fastened to the cover glass 1 by adhesion, for example by a double-sided adhesive tape 2. In a fourth method step IV, an adhesion layer 4 is applied to an end side of the display housing 9' facing the cover glass 1 and / or activated by, for example, light or heat.In a fifth method step V, the combination of cover glass 1 and liquid crystal panel 12 is inserted into the display housing 9' and connected to the display housing 9', thereby fixing the first free end 5a of the flexible printed circuit board 5 between the cover glass 1 and the display housing 9', and thereby sealing the display housing 9' from the environment, preferably in a dust- and water-tight manner.

[0038] The first free end 5a of the flexible printed circuit board 5 is led out of the display housing 9', in particular parallel to a surface 1a of the cover glass 1 of the liquid crystal panel 12. The flexible printed circuit board 5 can have a stiffener 17 which is firmly connected to at least part of the stiffener 17 in a section 5c which is equipped with electrical and / or electronic components 14 and / or connects the flexible printed circuit board 5 to the display housing 9' in regions of the stiffener 17 which extend beyond the section 5c in the longitudinal direction L of the flexible printed circuit board 5 and are not connected to the flexible printed circuit board 5.

[0039] In a subsequent sixth method step VI, the flexible printed circuit board 5 can be connected to the main circuit board 8 by the second free end 5b, and the main circuit board 8 can be connected to the backlight unit 11 by a connector 6. In a seventh method step VII, the display housing 9' and the main circuit board 8 can be enclosed by a rear cover 7, so that the flexible printed circuit board 5 or its section 5c equipped with electrical or electronic components 14 is arranged in front of the cover glass 1 between an outer side of the display housing 5 and an inner side of the rear cover 7'.

Claims

[1] Display (100; 100'), with a cover glass (1), a Liquid Crystal Panel (12) a flexible printed circuit board (5) having a first free end (5a), a second free end (5b) and a section (5c) equipped with electrical and / or electronic components (14) between the first and the second free end (5a, 5b), a backlight unit (11) and a display housing (9; 9'), wherein the section (5c) of the flexible printed circuit board (5) equipped with the components (14) is arranged outside the display housing (9; 9') and the first free end (5a) of the flexible printed circuit board (5) is connected to the liquid crystal panel (12) and the flexible printed circuit board (5) is connected to the cover glass (1) and the display housing (9; 9') in a region between the first free end (5a) and the section (5c) equipped with the components (14). [2] Display according to claim 1, wherein an adhesive layer (2) between the cover glass (1) and the flexible circuit board (5) seals the interior of the display housing (9; 9') from the environment in order to prevent the penetration of dust and moisture into the display housing (9; 9'). [3] Display according to one of the preceding claims, wherein the flexible printed circuit board (5) has a reinforcement or stiffening (17) in or in front of and / or behind the section (5c) equipped with the components (14) and / or rests on a support (9c) formed by the display housing (9). [4] Display according to one of the preceding claims, wherein the first free end (5a) of the flexible circuit board (5) extends parallel to the cover glass (1) from outside the display housing (9; 9') to the liquid crystal panel (12). [5] Display according to one of the preceding claims, wherein the display housing (9; 9') comprises a profile edge (16) extending away from the cover glass (1) with an upper side (16a) running parallel to a plane spanned by the cover glass (1) and an outer side (16b) extending perpendicular thereto away from the cover glass (1), wherein the upper side (16a) has an opening (16c) which is covered by the section (5c) of the flexible printed circuit board (5) with the components (14), so that the components (14) lie within the profile edge (16). [6] Display according to one of the preceding claims, wherein the display (100) is connected to a main circuit board (8) and a rear cover (7), wherein the rear cover (7) has a resealable inspection opening (7a) in the region of the flexible circuit board (5). [7] Display according to one of the preceding claims, wherein the flexible circuit board (5) connects the liquid crystal panel (12) to a main circuit board (8), wherein the flexible circuit board (5) is arranged outside the display housing (9; 9') except for the first free end (5a). [8] Method for assembling a display (100), in which in a first method step (I) a cover glass (1) is connected to a liquid crystal panel (12) and provided, in a second method step (II) a display housing (9; 9') with a backlight unit (11) is provided, in a third process step (III) a first free end (5a) of a flexible printed circuit board (5) is connected to the liquid crystal panel (12) and attached to the cover glass (1) by adhesion, in a fourth method step (IV) an adhesion layer (4) is applied and / or activated on a front side of the display housing (9; 9') facing the cover glass (1), in a fifth process step (V) the combination of cover glass (1) and liquid crystal panel (12) is connected to the display housing (9; 9') and thereby the first free end (5a) of the flexible printed circuit board (5) is fixed between the cover glass (1) and the display housing (9; 9'). [9] Method according to claim 8, wherein the first free end (5a) of the flexible printed circuit board (5) is led out of the display housing (9; 9') parallel to a surface (1a) of the cover glass (1) of the liquid crystal panel (12). [10] Method according to claim 8 or 9, wherein the flexible printed circuit board (5) has a stiffener (17), and the flexible printed circuit board (5) is firmly connected to at least part of the stiffener (17) in a section (5c) which is equipped with electrical and / or electronic components (14) and / or is connected to the display housing (9; 9') in regions of the stiffener (17) which extend in the longitudinal direction (L) of the flexible printed circuit board (5) beyond the section (5c) and are not connected to the flexible printed circuit board (5).

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