Liquid crystal cells – elements and systems – Particular structure – Holder – support – frame – or housing
Reexamination Certificate
2002-01-23
2004-10-05
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Holder, support, frame, or housing
C349S187000
Reexamination Certificate
active
06801269
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for connecting display panel substrates, and to a device for implementing same.
2. Description of Related Art
A display panel is fabricated by connecting together two substrates. A conventionally used substrate connecting process is now described with reference to FIG.
9
. As illustrated in this diagram, a first substrate
110
is held on a first surface table (also known as “upper surface table”)
142
provided with an X-axis driving mechanism
132
. Similarly, a second substrate
112
provided with a sealant is held on a second surface table (also known as “lower surface table”)
144
provided with a Y axis driving mechanism
134
. Whilst observing alignment marks provided on the first substrate
110
and the second substrate
112
, the X axis, Y axis are adjusted, along with a &thgr; axis by means of a &thgr; table
162
position beneath the second surface table
144
. In other words, the second substrate
112
is aligned in position with the first substrate by rotating it in a horizontal plane by means of a rotating driving mechanism
136
. Thereupon, the substrates are pressurized and connected by means of vertical raising and lowering means
138
and a pressure cylinder
160
capable of moving the first surface table
142
or second surface table
144
in the direction of arrow A. Since the gap between the two substrates (hereinafter, called “cell gap”) is not uniform, display irregularities occur. Therefore, in order to maintain display quality, it is necessary to maintain an appropriate cell gap. This technology is called “Cell Gap Control”. A substrate pressurizing mechanism comprising the aforementioned X axis driving mechanism
132
, Y axis driving mechanism
134
, rotation driving mechanism
136
, vertical raising and lowering means
138
, and pressure cylinder
160
is generally known in the prior art, comprising a variety of mechanisms. Therefore, since a mechanism of this kind can be constructed readily by a specialist in this field, detailed description thereof is omitted here.
For example, the connecting process in the fabrication of liquid crystal display elements using glass substrates, or the like, is performed by inserting a spacer made from glass fibre, or the like, together with the sealant, whilst simultaneously scattering a spacer made from resin, silica, or the like, over the entire interior surface of the cell between the substrates. However, this involves a detrimental effect in that the spacers reduce the contrast, and the like. In order to improve display quality, a so-called “spacerless” liquid crystal display is anticipated, wherein precise cell gap control can be achieved without placing spacers inside the cells.
Moreover, in organic EL panels, and the like, which have been the subject of increasing demand in recent years, it is not possible to place spacers on the entire interior surface of the cells, and hence precise cell gap control has not been achieved.
Furthermore, in the case of a liquid crystal display element using glass substrates, or the like, in order to sealing the interior of the cell completely, it is necessary to implement a process for initially placing the sealant, following by a process for sealing the opening section used to introduce the liquid crystal medium by providing sealant on that opening section, and therefore it has not been possible to provide sealant in such a manner that the interior of the cell is sealed completely in a single process. Consequently, the process for sealing the opening section is appended after the introduction of the liquid crystal medium, and therefore it is difficult to guarantee the adhesive strength of the sealed section, thereby giving rise to problems such as leaking of the liquid crystal medium after sealing, or the like.
Furthermore, in the case of an organic EL panel, since it is necessary to expel the air inside the cell when connecting the substrates, in many cases, rather than sealing the panel completely with the sealant, a process is adopted whereby a small gap is left in a portion of the panel and this gap is sealed at the same time that the substrates are pressurized and the cell gap is determined. However, problems frequently occur with respect to the adhesive strength of the sealing of this gap, and as a consequence, the display quality of the panel is degraded, and product lifespan is shortened.
SUMMARY OF THE INVENTION
The present invention was devised with the foregoing problems in view, an object thereof being to provide a method for connecting display panel substrates, and a device for implementing said method, whereby, in a substrate connecting process, it is possible to seal the entire circumference of the cell in a single sealing process using a sealant material, in other words, an individual sealing process, whilst simultaneously being able to set the cell gap readily and precisely, to a high degree of accuracy.
In order to achieve the aforementioned object, the method for connecting display panel substrates according to the present invention comprises the steps of:
(1) aligning the positions of and holding a first substrate and a second substrate whereon sealant material is disposed so as to form a waste region in the inner side region of the edges of the first and second substrates;
(2) inserting a spacer in the waste region between the first and second substrates;
(3) setting the cell gap by pressing the first and second substrates;
(4) hardening the sealant material; and
(5) withdrawing the spacer.
In this way, according to the present invention, the sealant material is hardened after the cell gap between the two substrates has been adjusted and determined by the spacer. Therefore, it is possible to readily to set the cell gap correctly to a high degree of accuracy. Consequently, this invention is particularly suitable for use in fabricating organic EL panels, and the like, as well as fabricating liquid crystal panels which employ a so-called pre-connection injection process.
In implementing this invention, if the connection is performed inside an air-tight processing chamber, suitably, a further step of evacuating the processing chamber from normal pressure to vacuum (or vacuum pressure) is included between step (1) and step (2).
In this way, by adopting a composition for causing the substrates to adhere together inside a vacuum processing chamber, in particular, in the manufacturing process for an organic EL panel wherein the material used in manufacture are sensitive to moisture and oxygen, it is possible to eliminate factors which can significantly affect the quality of the panel, whilst being able to control the cell gap accurately by means of a simple process.
A preferred embodiment of the invention includes, between step (2) and step (3), a step of returning the processing chamber in a vacuum state to normal pressure whilst maintaining a pressure difference of substantially zero between the expected cell interior space of the processing chamber and the space outside the expected cell interior space.
By adopting this composition, occurrence of deformation in the substrates is suppressed, and hence the cell gap can be controlled accurately. Therefore, this method is particularly suitable for use in the manufacture process of a display panel using flexible substrates, for example.
Moreover, in a preferred embodiment of the invention, during step (1) to step (4), the first and second substrates are respectively fayed with and held on first and second surface tables, whilst drawing a vacuum between the outer faces of the first and second substrates on the other sides thereof to the mutually opposing inner faces of the substrates, and contact surfaces of the first and second surface tables which respectively confront these outer sides of the substrates.
In this case, in particular, if the connection is performed inside a processing chamber, the air suction power for evacuating the processing chamber as a whole should be less than the air suction power for hermetically seal
Duong Thoi V.
Kim Robert H.
Lan Technical Service Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Method and device for connecting display panel substrates does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for connecting display panel substrates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for connecting display panel substrates will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3326020