Patent Application
20140104540
This application claims the benefit of Taiwan application Serial No. 101137748, filed Oct. 12, 2012, the disclosure of which is incorporated by reference herein in its entirety.
The present disclosure relates to the field of liquid crystal (LC) panel, and more particularly, to a LC panel without a polyimide alignment layer.
LC display has been intensely developed in the display industry for years, and a LC panel or cell can be the key device therein. The LC panel is basically composed of LC molecules sandwiched and sealed between two parallel glass substrates. To keep the LC molecules aligned in a predetermined incline direction (as referred to the pre-tilt angle), an alignment film is formed on the glass substrates. Usually the alignment film is made of polyimide (PI) uniformly coated on the substrates. After being baked and rubbed, the alignment film is capable of aligning the LC molecules. However, the fabrication of the alignment film would get along with its cost and may induce possible contaminations on the substrates, which negatively affects the LC panel's fabrication cost and yield.
Recently PI-free LC displays have been proposed, wherein the LC molecules are aligned due to the ultra-violet (UV) excitation. The reactive monomers in the LC solution may aggregate on the glass substrate after the UV light exposure to form a polymer layer which is capable of aligning the LC molecules. Thus no additional alignment film has to be coated in the PI-free LC displays, but the alignment stability and reliability of the LC molecules therein are not good enough. Consequently, it is in need to develop a new PI-free LC display.
According to one aspect of the present disclosure, one embodiment provides a LC panel, which includes: a first substrate and a second substrate opposing the first substrate, arranging the first substrate to face the second substrate; a LC layer containing a plurality of LC molecules interposed between the first substrate and second substrate; and a plurality of vertical alignment molecules, each comprising a long-chain alignment terminal, a cross-linking terminal, and at least one bonding terminal; wherein the at least one bonding terminal couples the vertical alignment molecule to the first or second substrate to form a surface bonding, the long-chain alignment terminals are parallel to each other and perpendicular to the first or second substrate, the cross-linking terminals link the neighboring vertical alignment molecules together, and the LC molecules are vertically aligned between the first and second substrates by means of the long-chain alignment terminals.
Each of the vertical alignment molecules may further comprise either a Si atom or an N atom for bonding the long-chain alignment terminal, the cross-linking terminal, and the at least one bonding terminal.
The long-chain alignment terminal may comprise an alkyl group, an alkylene group, or a benzene-ring compound.
The bonding terminal may be selected from the group consisting of O—CH2—C(Z)═CH2, O—(CH2)n—O—CO—C(Z)═CH2, (CH2)n—O—CO—C(Z)═CH2, O—(CH2)n—C(Z)═CH2, O—(CH2—CH2—O)n—CO—C(Z)═CH2, (CH2—CH2—O)n—CO—C(Z)═CH2, O—(CH2—CH2—O)n—C(Z)═CH2, (CH2—CH2—O)n—C(Z)═CH2, O—CO—C(Z)═CH2, O—CH3, O—C2H5, and O—H, wherein n is a positive integer and Z is a methyl group or a hydrogen group.
The cross-linking terminal may be selected from the group consisting of O—CH2—C(Z)═CH2, CH2—C(Z)═CH2, O—(CH2)n—O—CO—C(Z)═CH2, (CH2)n—O—CO—C(Z)═CH2, O—(CH2)n—C(Z)═CH2, (CH2)n—C(Z)═CH2, O—(CH2—CH2—O)n—CO—C(Z)═CH2, (CH2—CH2—O)n—CO—C(Z)═CH2, O—(CH2—CH2—O)n—C(Z)═CH2, (CH2—CH2—O)n—C(Z)═CH2, O—CO—C(Z)═CH2, O—CH3, O—C2H5, and O—H, wherein n is a positive integer and Z is a methyl group or a hydrogen group
According to another aspect of the present disclosure, another embodiment provides a LCD apparatus, which includes a backlight unit; and a LC panel comprising: a first substrate and a second substrate opposing the first substrate, arranging the first substrate to face the second substrate; a LC layer containing a plurality of LC molecules interposed between the first substrate and second substrate; and a plurality of vertical alignment molecules, each comprising a long-chain alignment terminal, a cross-linking terminal, and at least one bonding terminal; wherein the at least one bonding terminal couples the vertical alignment molecule to the first or second substrate to form a surface bonding, the long-chain alignment terminals are parallel to each other and perpendicular to the first or second substrate, the cross-linking terminals link the neighboring vertical alignment molecules together, and the LC molecules are vertically aligned between the first substrate and second substrate by means of the long-chain alignment terminals.
According to another aspect of the present disclosure, another embodiment provides a LC panel, which includes a first substrate and a second substrate opposing the first substrate, arranging the first substrate to face the second substrate; a LC layer containing a plurality of LC molecules interposed between the first substrate and second substrate; and a plurality of vertical alignment molecules interposed between the first substrate and the LC layer and between the second substrate and the LC layer, each vertical alignment molecule comprising a first terminal, a second terminal, and a third terminal; wherein the first terminal comprises one of an alkyl group, an alkylene group, and a benzene-ring compound, and one of the second and third terminals comprises an O atom.
The cross-linking terminal may have a photo-polymerization group for linking the cross-linking terminals of the neighboring vertical alignment molecules together after exposed to ultra-violet light.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.
The present disclosure will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present disclosure and wherein:
For further understanding and recognizing the fulfilled functions and structural characteristics of the disclosure, several exemplary embodiments cooperating with detailed description are presented as the following. Reference will now be made in detail to the preferred embodiments, examples of which are illustrated in the accompanying drawings.
In the following description of the embodiments, it is to be understood that when an element such as a layer (film), region, pattern, or structure is stated as being “on” or “under” another element, it can be “directly” on or under another element or can be “indirectly” formed such that an intervening element is also present. Also, the terms such as “on” or “under” should be understood on the basis of the drawings, and they may be used herein to represent the relationship of one element to another element as illustrated in the figures. It will be understood that this expression is intended to encompass different orientations of the elements in addition to the orientation depicted in the figures, namely, to encompass both “on” and “under”. In addition, although the terms “first”, “second” and “third” are used to describe various elements, these elements should not be limited by the term. Also, unless otherwise defined, all terms are intended to have the same meaning as commonly understood by one of ordinary skill in the art.
The bonding terminal 135 is designed to form a bond between the vertical alignment molecules 132 and either the first substrate 110 or the second substrate 120, so as to make the vertical alignment molecules 132 fixed onto the surface of the first substrate 110 or the second substrate 120. The long-chain alignment terminal 133 is designed to stand vertically on the substrate 110 or 120. In other words, the long-chain alignment terminal 133 can be parallel to each other and perpendicular to the surface of the first substrate 110 or the second substrate 120. Thus the vertical alignment is inherent in the vertical alignment molecules 132. Due to the vertical alignment of the vertical alignment molecules 132, the LC molecules 131 can be vertically aligned between the first substrate 110 and the second substrate 120. Thereby, the LC panel 100 can be used in the field of vertical alignment LC displays (VA-LCDs), in which the liquid crystals naturally align vertically to the glass substrates. Moreover, the cross-linking terminal 134 can link the neighboring vertical alignment molecules 132 together, so that the vertical alignment molecules 132 can be cross-linked to form a polymer film on the first substrate 110 or the second substrate 120. Thus the LC molecules 131 can be well aligned and the vertical alignment molecules 132 can be well polymerized, so as to alleviate light leakage in a LC panel caused by some LC alignment defects and hence improve the LCD's reliability.
Both the first substrate 110 and the second substrate 120 may be made of glass as glass substrates. But it is not limited thereto in this disclosure; they may also be insulation substrates, ceramic substrates, plastic substrates, or flexible substrates. The first substrate 110 may include a first electrode layer disposed thereon, which may be made of transparent conductive material, such as indium in oxide (ITO). The second substrate 120 may include a second electrode layer disposed thereon, which may be made of transparent conductive material, such as indium tin oxide (ITO). In the embodiment, the first substrate 110 is a thin-film transistor (TFT) substrate which is a glass substrate with a TFT layer formed thereon, and the second substrate 120 is a color filter (CF) substrate which is a glass substrate with a CF layer formed thereon. But it is not limited thereto in this disclosure, a CF substrate may be used as the first substrate 110 and a TFT substrate may be used as the second substrate 120.
In the embodiment, the vertical alignment molecules 132 may further include either a silicon (Si) atom or a nitrogen (N) atom, which is an element for bonding the long-chain alignment terminal 133, the cross-linking terminal 134, and the at least one bonding terminal 135. In the following embodiments, a Si atom is used as the bonding element in a first example and an N atom as the bonding element in a second example. To describe the structure of the vertical alignment molecules 132, the relation between the vertical alignment molecules 132 and the LC molecules 131, and the relation between the vertical alignment molecules 132 and the substrate 110 or 120,
In the first example, a Si atom is used as the bonding element of the vertical alignment molecule 132, which can be a silane coupling agent with a chemical structure shown in
As shown in
wherein n is a positive integer, X is selected from the group consisting of hydrogen (H), chlorine (Cl), fluorine (F), bromine (Br), iodine (I), hydroxyl group (OH) and CH4, and Y is selected from the group consisting of H, Cl, F, Br, I, OH and CH4. It should be understood that various vertical alignment molecules 132 in an individual LC panel may have different compositions of T1 or the long-chain alignment terminal 133 from each other. That is, the vertical alignment molecules 132 can be a mixture of vertical alignment molecules with different compositions of T1.
As shown in
As shown in
In one embodiment, bi-acrylic monomers can be added into the LC layer 130 before the photo polymerization. The bi-acrylic monomers are used to reinforce the alignment capacity of the vertical alignment molecules 132. For example, the bi-acrylic monomers can be made of 4,4′-bisacryloyl-biphenyl with its chemical formula
or 4,4′-bis[4-(acryloyxy) hexyloxy]biphenyl with its chemical formula
Moreover, the cross-linking terminal 134 may contain a photo-polymerization functional group, configured for linking the cross-linking terminals 134 of the neighboring vertical alignment molecules 132 together after exposed to ultra-violet (UV) light. A mercury lamp of middle, high or ultra-high pressure can be used to emit the UV light with its wavelength in the range from 100 nm to 400 nm. A photo-initiator may be added into the LC layer 130 to facilitate the cross-linking between the vertical alignment molecules 132 and the bi-acrylic monomers. For example, the photo-initiator can be made of phenyl ketone such as 1-hydroxy-cyclohexylphenyl-ketone with its chemical formula
In the second example, an N atom is used as the bonding element of the vertical alignment molecule 132 with its chemical structure shown in
In the embodiments, the surface bonding formed between the vertical alignment molecules 132 and the glass substrate 110 or 120 are used in the LC panel 100, so that the vertical alignment molecules 132 can be fixed onto the surface of the glass substrate 110 or 120. Due to the long-chain alignment terminal 133, the vertical alignment molecules 132 can stand vertically on the glass substrate 110 or 120, so that the LC molecules 131 can be vertically aligned between the glass substrates 110 and 120. Thus, forming a vertical alignment layer such as a polyimide (PI) film can be avoided in the fabrication process of the TFT and CF substrates. This makes the LC panel 100 in the embodiments excused from the problems due to the vertical-alignment film formation on the glass substrates, and makes the fabrication cost of the LC panel reduced, also.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the disclosure, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101137748 | Oct 2012 | TW | national |
