The present invention relates to liquid crystal displays (LCDs), and particularly to chip on glass (COG) type LCDs.
Compared with CRTs (cathode ray tubes), LCDs have a number of advantages including a lower driving voltage, lower power consumption, lower radiation, thinness, and lightness (in weight). Thus, LCDs are applied in numerous kinds of video devices and communication devices. A typical LCD includes a driving integrated circuit (IC). Bonding technologies for securing the driving IC in an LCD have developed from earlier chip on board (COB) and tape carrier bonding (TAB) techniques to the more recent COG, chip on film (COF), etc techniques.
Referring to
The lower glass substrate 12 has an input wiring pattern 161 and an output wiring pattern 162 formed thereon. The driving IC 13 includes a plurality of aligned first solder bumps 151 overlying an end portion of the input wiring pattern 161, and a plurality of aligned second solder bumps 152 overlying an end portion of the output wiring pattern 162. The driving IC 13 electrically communicates with a plurality of display switching elements (not shown) formed on the lower glass substrate 12 of the LCD 1 by way of the ACF 17 electrically connecting the first solder bumps 151 with the input wiring pattern 161. In addition, the driving IC 13 electrically communicates with the FPC 14 by way of the ACF 17 electrically connecting the second solder bumps 152 with the output wiring pattern 162.
Referring also to
The lower glass substrate 12 of the LCD 1 is normally provided with a larger area than the upper glass substrate 11. Thus the lower glass substrate 12 provides an exposed edge area necessary for mounting of the driving IC 13 and the FPC 14. The need for the edge area means that the overall size of the LCD 1 may be excessively large. Thus the LCD 1 may not be suitable for certain compact applications. In addition, the driving IC 13 is essentially mounted directly on the lower glass substrate 12, whereby the driving IC 13 faces the end of the upper glass substrate 11. However, the driving IC 13 is generally thicker and higher than the upper glass substrate 11, which further increases the overall thickness size of the LCD 1.
What is needed, therefore, is a more compact LCD.
In a preferred embodiment, a liquid crystal display includes a first panel, a second panel opposite to the first panel, a liquid crystal layer sandwiched between the two panels, a light guide plate and an integrated circuit (IC) provided at a same side of the second panel, the light guide plate and the IC facing each other, and a light source adjacent to the IC, the light source and the light guide plate cooperatively providing light beams that pass through the second panel, the liquid crystal layer and the first panel.
In another preferred embodiment, a liquid crystal display includes a first panel, a second panel opposite to the first panel, a liquid crystal layer sandwiched between the two panels, a light guide plate and an integrated circuit (IC) under the second panel, and a light source disposed on the IC, wherein the light source faces an edge of the light guide plate, and the integrated circuit electrically connects directly with the light source.
Because the LCDs has set the light source disposed on the IC faces the light guide plate, and the light source and the light guide plate cooperatively provide light beams that pass through the second panel, the liquid crystal layer and the first panel, whereby a space adjacent to the light guide plate and the lower panel is efficiently utilized to receive the IC. Therefore, the LCDs have a high space utilization ratio and a compact size. In addition, the IC electrically connects directly with the light source, whereby there is no needed to provide other elements for electrically connecting the light source with an external power source. Therefore, the structure of the LCD has been simplified.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Referring to
The lower panel 42 includes: a first surface 421, most of which abuts the upper panel 41; a second surface 422, most of which abuts the light guide plate 400; an input wiring pattern 49 formed on an end portion of the first surface 421, for inputting signals to drive the panels 41, 42; a plurality of aligned first through holes 461 adjacent to one end of the input wiring pattern 49; and a plurality of aligned second through holes 462 adjacent to one end of the FPC 44. The line of second through holes 462 is spaced a short distance from and is parallel to the line of first through hole 461. The lower panel 42 further includes a first guide pattern 481 and a second guide pattern 482. The first guide pattern 481 extends from the second surface 422 through the first through holes 461 to connect with the input wiring pattern 49. The second guide pattern 482 extends from the second surface 422 through the second through holes 462 to the first surface 421.
The light guide plate 400 has a light entrance surface 402 at an edge thereof nearest the IC 43, and the IC 43 has a side surface 430 facing toward the light entrance surface 402. A light source 410 is disposed on the side surface 430, and faces the light entrance surface 402 of the light guide plate 400. The light source 410 may be one or more light emitting diodes (LEDs), which can be formed by depositing suitable semiconductor material on the side surface 430. Further, to simplify the structure of the LCD 4, a driving circuit for the light source 410 can be integrated into the IC 43. That is, it can simplify the LCD 4 that the IC 43 can drive and control the light source 410. The light source 410 and the light guide plate 400 cooperatively provide guided light beams that pass through the lower panel 42, the liquid crystal layer and the upper panel 41 in order to provide displaying of images by the LCD 4.
The IC 43 includes a plurality of first solder bumps 451 disposed corresponding to the first guide pattern 481, and a plurality of second solder bumps 452 disposed corresponding to the second guide pattern 482 and spaced apart from the first solder bumps 451. The first and second solder bumps 451, 452 may be spherical or generally rectangular protrusions. Typically, the first and second solder bumps 451, 452 are plated with gold.
The IC 43 electrically communicates with a plurality of display switching elements (not shown) formed on the lower panel 42 of the LCD 2 via a first portion of the first ACF 471 and the first guide pattern 481. That is, the first portion of the first ACF 471 and the first guide pattern 481 cooperatively electrically connect the first solder bumps 451 of the IC 43 with the input wiring pattern 49 of the lower panel 42. In addition, the IC 43 electrically communicates with the FPC 44 via a second portion of the first ACF 471, the second guide pattern 482, and the second ACF 472. That is, the second portion of the first ACF 471, the second guide pattern 482 and the second ACF 472 cooperatively electrically connect the second solder bumps 452 of the IC 43 with the FPC 44.
The IC 43 electrically communicates with the switching elements of the LCD 4 and with the FPC 44 via mechanical and electrical bonding of the first and second ACFs 471, 472 to their respective adjoining components. In particular, a bonding process is performed under pressure and heat during manufacturing and assembly of the LCD 2. Electrical communication between the first solder bumps 451 and the first guide pattern 481, between the second solder bumps 452 and the second guide pattern 482, and between the second guide pattern 482 and the FPC 44, is only established where conductive particles (not shown) in the respective first and second ACFs 471, 472 are compressed. That is, the compression is performed selectively and anisotropically, to achieve the desired corresponding electrical connectivity.
The manufacturing and assembly process involving bonding of the IC 43 on the lower panel 42 includes the following steps: firstly, adhering the first ACF 471 on the second surface 422 of the lower panel 42, with an edge of the first ACF 471 facing the edge of the light guide plate 400, and the first ACF 471 being positioned corresponding to the first and second through holes 461, 462 and the first and second guide patterns 481, 482; secondly, adhering the second ACF 472 on the first surface 421 of the lower panel 42, with an edge of the second ACF 472 facing toward a nearest edge of the upper panel 41, and the second ACF 472 being positioned corresponding to the second guide pattern 482; thirdly, press-bonding and heating the IC 43 on the first ACF 471, thereby electrically connecting the first solder bumps 451 of the IC chip 43 with the first guide pattern 481, and the second solder bumps 452 of the IC chip 43 with the second guide pattern 482, both connections being attained through corresponding of the conductive particles of the first ACF 471; and finally press-bonding and heating the FPC 44 on the second ACF 472, thereby electrically connecting the FPC 44 with the second guide pattern 482, the connection being attained through corresponding of the conductive particles of the second ACF 472.
In operation, the FPC 44 provides external signals to the IC 43 through the second ACF 472, the second guide pattern 482, the second portion of the first ACF 471, and the second solder bumps 452 of the IC 43. When the IC 43 receives the external signals, the IC 43 sends driving signals to the switching elements of the lower panel 42. The driving signals are sent through the first solder bumps 451, the first portion of the first ACF 471, the first guide pattern 481, and the input wiring pattern 49 of the lower panel 42, and drive the switching elements to respectively turn on or turn off. Thereby the LCD 4 displays corresponding images.
In summary, the LCD 4 has the IC 43 and the light guide plate 400 set on the second surface 422 of the lower substrate 42, with the light source 410 disposed on the IC 43 facing the light guide plate 400. Thereby, a space adjacent to the light guide plate 400 and the lower panel 42 is efficiently utilized. Therefore, the LCD 4 has a high space utilization ratio and a compact size. In addition, the IC 43 drives and controls the light source 410, that is, the IC 43 and the light source 410 electrically connect with each other, whereby there is no need to provide other elements for electrically connecting the light source 410 with an external power source. Therefore, the structure of the LCD 4 is simplified.
It is to be further understood that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
---|---|---|---|
94204243 | Mar 2005 | TW | national |