Patent Application
20100201934
1. Field of the Invention
The present invention relates to a display panel, and in particular relates to a liquid crystal display panel formed by a one drop fill (ODF) method.
2. Description of the Related Art
Typically, a liquid crystal display (LCD) panel includes a color filter substrate and a thin film transistor substrate which are disposed opposite to each other. Spacers are disposed between the two substrates to maintain a predetermined gap size between the substrates. An LCD panel is formed by using a seal material, assembling two substrates into a liquid crystal cell with one injection opening. The injection opening is used for the injection of liquid crystal material. After filling of the liquid crystal material, the injection opening is closed by a seal material.
One negative aspect of the aforementioned method is that it is complicated. Accordingly, a newly proposed technique based on a one drop fill (ODF) method has been disclosed in U.S. Pat. No. 5,263,888, to simplify forming of an LCD panel. In the method, droplets of liquid crystal material are dropped onto the color filter substrate or the thin film transistor substrate before the two substrates are assembled. This is greatly reducing the manufacturing steps required and increasing manufacturing efficiency. However, the quantity of the droplets of liquid crystal material must be precisely controlled. A deficient amount of liquid crystal material may cause the LCD panel to have voids. An excess amount of liquid crystal material may cause the LCD panel to have uneven cell gaps resulting in gravity mura.
In the ODF method, the quantity of the liquid crystal material may be insufficient or too much. Fortunately, because the substrates which form the LCD panel are slightly elastic, the substrates may be slightly bent such that liquid crystal material completely fills the liquid crystal cell. Thus, no void or gravity mura is observed.
Thus, a high bending degree of the two substrates is desired. The bending degree of the two substrates is determined by the density of the spacers distributed therebetween. When the spacers are disposed with low density, the two substrates may be bent to a higher degree, which allows a wider range of the drop quantity of the liquid crystal material. However, when the density of the spacers is low, the spacers may be damaged easily during assembly the two substrates.
Thus, a new display panel and manufacturing method thereof which can reduce the problems mentioned above are desired.
BRIEF SUMMARY OF THE INVENTION
According to an illustrative embodiment, a display panel is provided. The display panel includes a first substrate having a first surface, and a second substrate having a second surface facing the first surface and having at least an opening portion extending downward from the second surface, wherein the opening portion occupies an area no greater than that occupied by a portion of the second surface other than the opening portion. A liquid crystal layer is sandwiched between the first substrate and the second substrate. At least a first spacer is disposed between the first substrate and the second substrate, and at least a second spacer is disposed between the first substrate and the second substrate, wherein an end of the second spacer is within the opening portion.
According to another illustrative embodiment, a display panel is provided. The display panel includes a first substrate having a first surface, a second substrate having a second surface facing the first surface, a liquid crystal layer sandwiched between the first substrate and the second substrate, and a plurality of opening portions extending downward from the second surface, wherein the opening portions occupy areas no greater than that occupied by a portion of the second surface other than the opening portions. A plurality of first spacers is disposed between the first substrate and the second substrate, and a plurality of second spacers is disposed between the first substrate and the second substrate, wherein each end of the second spacers is correspondingly within one of the opening portions.
According to an illustrative embodiment, a method for forming a display panel is provided. The method includes providing a first substrate having a first surface, providing a second substrate having a second surface, forming at least a first spacer and at least a second spacer on the first surface, forming a liquid crystal layer on the first surface or the second surface, and forming at least an opening portion extending downward from the second surface, wherein the opening portion occupies an area no greater than that occupied by a portion of the second surface other than the opening portion, and aligns and superposes the first substrate and the second substrate to each other such that an end of the second spacer is within the opening portion.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
It is understood, that the following disclosure provides many difference embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numbers and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Furthermore, descriptions of a first layer “on,” “overlying,” (and like descriptions) a second layer include embodiments where the first and second layers are in direct contact and those where one or more layers are interposing the first and second layers.
Then, a sealing structure 102 is formed on the first surface 100a, which encloses a pixel region. The material of the sealing structure 102 may include, for example, a light cured sealant or a metal material. Thereafter, at least a first spacer 104a and at least a second spacer 104b are formed on the first surface 100a of the first substrate 100. The first spacer 104a and the second spacer 104b may include a compressible material, such as a polymer material or a photoresist material. In one embodiment, a compressible material layer is first formed on the first surface 100a and then the compressible material layer is patterned to form a plurality of first spacers 104a and second spacer 104b. Areas or shapes of the cross-sections of the first spacer 104a and the second spacer 104b may be different from each other or the same. The areas or the shapes of the cross-sections of the plurality of first spacers 104a may be completely different from each other, completely the same, or partially different from each other. The areas or the shapes of the cross-sections of the plurality of second spacers 104b may be completely different from each other, completely the same, or partially different from each other. Distribution densities, shapes, sizes, and distribution locations of the first spacers 104a and the second spacers 104b can be designed according to requirements.
Referring to
Referring to
In this embodiment, first, the first substrate 100 and the second substrate 110 are aligned and superposed to each other. At this time, an end of the first spacer 104a (having a thickness t1) contacts with a portion of the second surface 110 other than the opening portion 112 of the second surface 110 and an end of the second spacer 104b is located above the opening portion 112 without contacting with the second substrate 110. At this step, the first substrate 100 and the second substrate 110 are separated from each other and supported merely by the first spacers 104a. Because the density of the spacers contacting the two substrates is lower at this moment (only the first spacers 104a), the substrates are capable of being slightly bended to finely adjust the space between the substrates depending on the quantity of the liquid crystal material dropped. Thus, the process window of the ODF method is wider than if spacers with higher density contact with the two substrates.
Then, as shown in
Then, the sealing structure 102 may be cured. For example, when the sealing structure 102 includes a light cured sealant, the sealing structure 102 is irradiated by a light, such as a UV light, to cure the sealing structure 102.
In the embodiment mentioned above, the opening portions and the spacers are respectively formed on different substrates. However, embodiments of the invention are not limited to a specific example. In another embodiment, opening portions and spacers may be formed on the same substrate. The opening portions correspond to partial spacers formed on opposite substrates. The process window of the one drop fill method may also be enlarged and the stability of the display panel may also be enhanced.
In addition, although the substrate of the embodiment shown in
Embodiments of the present invention may be employed in a variety of displays including transmissive display products and transflective display products, such as a twisted nematic (TN) type, super twisted nematic (STN) type, multi-domain vertical alignment (MVA) type, in-plane switching (IPS) type, fringe field switching (FFS) type, and patterned vertical aligned (PVA) type liquid crystal display.
Embodiments of the present invention have many advantageous features. For example, opening portions having a variety of shapes or distributions may be formed on the substrate corresponding to the positions of partial spacers disposed on an opposing substrate according to requirements. During alignment and when superposing the substrates, the spacers not corresponding to the opening portions may temporarily support and separate the two substrates from each other by a gap (crystal cell gap). At this time, the number of the spacers used to support and separate the substrates is relatively small and thus the two substrates still have a relatively high bending degree. Thus, in the ODF method, the step of dropping liquid crystal material has a wide allowable quantity range. After assembly of the substrates are accomplished, the remaining spacers correspondingly reach to the bottom of the opening portions to provide sufficient support. Thus, both a wide process window and a high structural strength are achieved for the display panel. In addition, numbers, shapes, positions, and distribution densities of the opening portions and the corresponding spacers may be designed according to requirements.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 098133573 | Oct 2009 | TW | national |
This Application claims the benefit of U.S. Provisional Application No. 61/152,200, filed on Feb. 12, 2009, the entirety of which is incorporated by reference herein. This Application claims priority of Taiwan Patent Application No. 98133573, filed on Oct. 2, 2009, the entirety of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61152200 | Feb 2009 | US |
