This invention is directed to the manufacture of a connector for liquid crystal displays (“LCDs”) that is adapted for electrical connection of an LCD panel and a conductive portion of a printed wiring board (PWB) or printed circuit board (PCB). This invention is further directed to a method of affixing an LCD panel to a PWB or PCB through an insulative connector having a plurality of contacts mounted thereon. As used herein, the terms PWB and PCB will be used interchangeably to denote a substrate having conductive elements to which an LCD is electrically connected.
Liquid crystal displays (“LCDs”) are being aggressively integrated into a multitude of contemporary electronic devices that previously employed cathode ray tubes (CRTs). “Liquid crystal” is a term that indicates the status of a substance that is neither solid nor liquid. When coming into contact with a grooved surface in a fixed direction, liquid crystal molecules line up in parallel along the grooves. Light travels through the spacing of the molecular arrangement. As the molecule arrangement is twisted, the light also “twists” as it passes through the liquid crystals. When a voltage is applied to the liquid crystal structure, the molecules rearrange themselves and the twisted light passes straight through. When voltage is applied to a combination of two polarizing filters and twisted liquid crystal, it becomes an LCD display. This is the principle behind conventional twisted nematic (TN) LCDs.
It is desirable to exploit the unique advantages of LCD displays, such as their compact size, thin profile, lightweight, low power consumption and ability to withstand elevated temperatures and vibrations, to produce items that are more compact and lightweight than CRTs. This means that LCDs can be used in many applications where a large CRT monitor does not fit or is impractical. Such products include LCD TVs, view cams, portable information tools (i.e. PDAs), computer monitors, A/V equipment, car navigation systems, game devices, large projection TVs and similar products. LCDs also deliver comparable performance in the display of color, resolution and brightness and further obviate the emission of harmful radiation attributable to emission by CRT monitors.
The typical LCD module includes a liquid crystal matrix mounted in or to a substrate that includes a plurality of discrete conductive regions disposed thereon. A liquid crystal cell is acquired by forming the requisite electrodes and then forming an alignment layer within which liquid crystal particles align themselves. Upper and lower glass substrates are thereafter coupled to one another and plastic beads are sandwiched therebetween. The substrates are then fixed, after which liquid crystals are injected into spaces between the plastic beads. Sealing of the LCD module is completed when external electronic elements, along with a driver, are connected to the electrodes of the finished cell.
Elastomeric connectors effect the most common method of connection of LCD modules to the conductive portion of a printed wiring board (PWB) or printed circuit board (PCB). Such connectors are generally silicone rubber strips made up of sequentially spaced conductive and non-conductive materials. Typical elastomeric connectors have at least one row of alternating layers of conductive and insulative compressible material that may be surrounded on its sides by a rubber supporting layer. The elastomeric connector is used in assemblies by mechanically confining the connector sides and compressing the connector through its height, thereby pressing the conductive elements in the connector onto conductive pads on the PWB and corresponding conductive pads on the LCD.
Increasing use of LCDs in delicate and complex electronic devices, however, increases the number of applications in which numerous interconnections must be made between the LCD and the PWB. Since there is limited space for these connections, it is imperative that the LCD pads and the PWB pads be tightly aligned over one another and that there be minimal angular skew in the conductive elements in the elastomer. This angle therefore becomes particularly important as the height of the connector increases. Absent such precise configuration, the conductors in the connector might not connect to the appropriate corresponding pads on the LCD and the PWB. In addition, since the connector is made from a rubbery material that is susceptible to movement under elevated temperature and vibrations, the retention of the elastomeric connectors to the PCB is minimal.
It is therefore desirable to provide an LCD surface mount connector that overcomes the problems inherent in elastomeric connectors. Particularly, it is desirable to provide such a connector that predictably and reliably retains conductive elements in precise alignment with one another.
It is therefore an advantage of the present invention to provide an improved LCD surface mount connector that obviates the above-described shortcomings of conventional elastomeric contacts.
It is another advantage of the present invention to provide an LCD surface mount connector that retains a plurality of contacts in an inexpensively molded insulative housing.
It is an additional advantage of the present invention to ensure that conductive elements of an LCD connector are correctly aligned with terminal pads of adjacent circuits during assembly of the connector between the circuits.
In accordance therefor with a particular arrangement of the invention, an electrical connector is provided for establishing electrical connection between a conductive portion of an LCD display and conductive elements of a printed circuit board. The connector includes a substantially planar integrally formed connector housing supportable on the printed circuit board, the housing having an upper surface, a lower surface and a peripheral wall. A plurality of electrical contacts are supported by the housing, each contact including an interior contact extent having a deflectable spring-like portion defined thereat. The interior contact extent provides for electrical engagement with the LCD conductor portion. Each electrical contact includes an exterior contact extent for termination to the printed circuit board. Each contact further includes a mid-section extent between the interior contact extent and the exterior contact extent, the midsection contact extents being secured to the housing allowing free connection of the interior contact extent to the printed circuit board and deflectable connection of the interior contact extent to the LCD conductor portions.
The present invention provides for an LCD surface mount connector that eliminates the angular skew and consequential connection problems that are inherent in conventional elastomeric connectors. In one arrangement of the present invention shown with respect to
Now referring to the drawing figures,
Pier 12 supports a plurality of laterally spaced contacts 16 thereby. Each contact 16 is provided in a clothespin-type configuration wherein a spring-like undulation 16a lies in parallel spaced relation to a substantially planar base 16b. Each contact 16 further includes a tail portion 16c that protrudes from a portion of side wall 12c opposite that from which base 16 extends.
As further shown in
Now referring to
Connector 30 further includes a plurality of contacts 36 that are stamped from a common ribbon 40 of a conductive metallic material as shown in FIG. 5. Contacts 36 are similar to contacts 16, having a spring-like undulation 36a extending in spaced linear relation to a co-terminal base 36b and a tail portion 36c that protrudes normally from side wall 32c in an opposing direction relative to base 36b. Each contact 36 further includes a mid-section 36d elevated by a distance d above a plane in which base 36b and tail portion 36c lie.
Contacts 36 are coupled with housing 32 so that the contacts are alternatingly disposed in housing 32 relative to posts 35 (as shown in FIG. 4). Contacts 36 are fitted into correspondingly configured recesses 38 in housing 32 so as to establish a friction fit therewithin. Contacts 36 may also be retained in housing 32 by any other appropriate coupling means, such as adhesive or the like. Posts 35 may alternatively be swaged over contacts 36 so as to ensure alignment and securement thereof.
An alternate form of the LCD surface mount connector of the present invention is further illustrated in
As further illustrated in
Referring to
Another alternate form of the LCD surface mount connector of the present invention is shown in
A contact 76 that is used in connector 70 is further shown in
In another arrangement of the present invention shown with respect to
Now referring to the drawing figures,
Housing 112 supports a plurality of laterally spaced contact 116 thereby. As further shown in
Contacts 116 are desirably assembled with housing 112 by performing an insert mold operation wherein housing 112 is directly molded around the contacts. In the alternative, contacts 116 may be press fit into correspondingly configured cavities in housing 112 so as to effect frictional engagement therewith. Such engagement may be achieved with or without the use of an adhesive or the like. Contacts 116 are thereby retained in alignment relative to one another and relative to pier 112 so as to effect sufficient aligned connection with requisite conductive elements on the LCD display and the PCB.
Housing 112 desirably retains a flexible condition wherein the housing itself acts as a leaf spring when connection therewith is established by a mating component. The top and bottom planar surfaces 112a and 112b respectively are substantially flexible. As the component exerts a downward force toward PCB 113, the housing planar portions 112a and 112b predictably exerts an upward force in response thereto, which is normal to contact point 117. Such normal force further ensures reliable contact between connector 110 and a mating component in engagement therewith.
Now referring to
As further shown in
In a further arrangement of the present invention shown in
Now referring to the drawing figures,
Housing 212 supports a plurality of laterally spaced contacts 216 thereby. As further shown in
Contacts 216 are desirably assembled with housing 212 by performing an insert mold operation wherein housing 212 is directly molded around the contacts. In the alternative, contacts 216 may be press fit into correspondingly configured cavities in housing 212 so as to effect frictional engagement therewith. Such engagement may be achieved with or without the use of an adhesive or the like. Contacts 216 are thereby retained in alignment relative to one another and relative to pier 212 so as to effect sufficient aligned connection with requisite conductive elements on the LCD display and the PWB.
In yet a further arrangement of the present invention shown in
Now referring to the drawing figures,
Contacts 314 are desirably assembled within housing 312 by performing an insert mold operation wherein housing 312 is directly molded around the contacts 314. In the alternative, contacts 314 may be pressed fit into correspondingly configured cavities in the housing 312 so as to effect frictional engagement therewith. Contacts 314 are thereby retained in alignment relative to one another so as to effect sufficient aligned connection with requisite conductive elements on the LCD display and the PWB.
While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the fundamental teachings of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
The present application claims priority to U.S. Provisional Application No. 60/203,239, filed May 8, 2000 entitled “LCD Connector Having Integrated Preload Feature”; U.S. Provisional Application No. 60/203,242, filed May 8, 2000 entitled “LCD Surface Mount Connector; U.S. Provisional Application No. 60/202,400, filed May 8, 2000 entitled “LCD Connector with Flexible Leaf-Spring Housing”; and U.S. Provisional Application No. 60/202,399 filed May 8, 2000 entitled “LCD Connector with Metallic Spring Contacts”.
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