Patent Application
20170075169
Smartphones, tablets, personal computers (PCs), and devices with liquid crystal displays (LCDs) have recently formed large markets, become popular types of mobile terminals, and changed the lifestyles of users dramatically. However, there remains a need to reduce the weight, thickness, and cost of these devices. Due to the large number of components in a conventional LCD, it is difficult to reduce the weight, thickness, and cost of the LCD device as well as the cost, time, and complexity of the manufacturing process.
In some embodiments, a backlight unit can comprise a thin film transistor array substrate; at least one ultraviolet light source configured to project ultraviolet light through the thin film transistor array substrate; and at least one layer of transparent fluorescent films formed on a top surface of the thin film transistor array substrate, wherein the layer comprises: a plurality of red transparent fluorescent films formed on a first subset of pixels on the top surface of the thin film transistor array substrate; a plurality of green transparent fluorescent films formed on a second subset of pixels on the top surface of the thin film transistor array substrate; and a plurality of blue transparent fluorescent films formed on a third subset of pixels on the top surface of thin film transistor array substrate, wherein the layer of transparent fluorescent films is configured to filter color.
In some embodiments, a liquid crystal display can comprise a backlight unit comprising a thin film transistor array substrate; at least one ultraviolet light source configured to project ultraviolet light through the thin film transistor array substrate; and at least one layer of transparent fluorescent films formed on the thin film transistor array substrate, wherein the layer comprises: a plurality of red transparent fluorescent films formed on a first subset of pixels on the thin film transistor array substrate; a plurality of green transparent fluorescent films formed on a second subset of pixels on the thin film transistor array substrate; and a plurality of blue transparent fluorescent films formed on a third subset of pixels on the thin film transistor array substrate, wherein the layer of transparent fluorescent films is configured to filter color. In some embodiments, the liquid crystal display can further comprise a liquid crystal layer disposed above the layer of transparent fluorescent films; and a glass substrate without a color filter formed thereon, wherein the glass substrate is disposed above the liquid crystal layer.
In some embodiments, a device comprising a liquid crystal display can comprise a liquid crystal display comprising a backlight unit comprising a thin film transistor array substrate; at least one ultraviolet light source configured to project ultraviolet light through the thin film transistor array substrate; and at least one layer of transparent fluorescent films formed on the thin film transistor array substrate, wherein the layer comprises: a plurality of red transparent fluorescent films formed on a first subset of pixels on the thin film transistor array substrate; a plurality of green, transparent fluorescent films formed on a second subset of pixels on the thin film transistor array substrate; and a plurality of blue transparent fluorescent films formed on a third subset of pixels on the thin film transistor array substrate, wherein the layer of transparent fluorescent films is configured to filter color. In some embodiments, the liquid crystal display can further comprise a liquid crystal layer disposed above the layer of transparent fluorescent films; and a glass substrate without a color filter formed thereon, wherein the glass substrate is disposed above the liquid crystal layer, In some embodiments, the device can be a mobile device, a cell phone, a tablet, a computer, a television, a monitor, or a display.
In some embodiments, a method of making a backlight unit can comprise providing a thin film transistor array substrate; disposing at least one ultraviolet light source at an edge of or beneath the thin film transistor array substrate so that the at least one ultraviolet light source is configured to project ultraviolet light through the thin film transistor array substrate; and forming at least one layer of transparent fluorescent films configured to filter color on a thin film transistor array substrate, wherein forming the layer comprises: forming a plurality of red transparent fluorescent films on a first subset of pixels on the thin film transistor array substrate, forming a plurality of green transparent fluorescent films on a second subset of pixels on the substrate; and forming a plurality of blue transparent fluorescent films on a third subset of pixels on the substrate.
In some embodiments, a method of forming a red transparent fluorescent film on a thin film transistor array substrate can comprise providing a red transparent fluorescent material; mixing the red transparent fluorescent material with a transparent resin based ink, thereby yielding a red transparent fluorescent ink; applying the red transparent fluorescent ink to a subset of pixels on the thin film transistor array substrate; and drying the red transparent fluorescent ink.
In some embodiments, a method of forming a green transparent fluorescent film on a thin film transistor array substrate can comprise providing a green transparent fluorescent material; mixing the green transparent fluorescent material with a transparent resin based ink, thereby yielding a green transparent fluorescent ink; applying the green transparent fluorescent ink to a subset of pixels on the thin film transistor array substrate; and drying the green transparent fluorescent ink.
In some embodiments, a method of forming a blue transparent fluorescent film on a thin film transistor array substrate can comprise providing a blue transparent fluorescent material; mixing the blue transparent fluorescent material with a transparent resin based ink, thereby yielding a blue transparent fluorescent ink; applying the blue transparent fluorescent ink to a subset of pixels on the thin film transistor array substrate; and drying the blue transparent fluorescent ink.
In some embodiments, a method of using a backlight unit can comprise providing a backlight unit comprising: a thin film transistor array substrate; at least one ultraviolet light source configured to project ultraviolet light through the thin film transistor array substrate; at least one layer of transparent fluorescent films formed on the thin film transistor array substrate, wherein the layer comprises: a plurality of red transparent fluorescent films formed on a first subset of pixels on the thin film transistor array substrate; a plurality of green transparent fluorescent films formed on a second subset of pixels on the thin film transistor array substrate; a plurality of blue transparent fluorescent films formed on a third subset of pixels on the thin film transistor array substrate, wherein the layer of transparent fluorescent films is configured to filter color. In some embodiments, a method of using a backlight unit can further comprise projecting the ultraviolet light through the thin film transistor array substrate, thereby causing the emission of red light from the red transparent fluorescent films, the emission of green light from the green transparent fluorescent films, the emission of blue light from the blue transparent fluorescent films, or a combination thereof.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
Conventional liquid crystal display (LCD) devices include multiple components that add to the weight, thickness, and manufacturing costs of the device. Examples of such components include a glass substrate for a thin-film transistor (TFT) array, thin-film transistors, a glass substrate for a color filter, a color filter, transparent electrodes, polarizers, alignment layers, a liquid crystal layer, a light guide plate, and multiple other components. In contrast, the embodiments disclosed herein are able to omit a light guide plate and a conventional color filter. Conventional LCDs typically project white light through a light guide plate disposed beneath the TFT array substrate. On the other hand, some embodiments disclosed herein project ultraviolet (UV) light directly through the TFT array substrate, thereby avoiding the need for a conventional light guide plate in the LCD. In addition, a layer of transparent fluorescent films that function as a color filter can be formed on the TFT array substrate in accordance with some embodiments. In some embodiments, the layer of transparent fluorescent films includes red, green, and blue transparent fluorescent films. Thus, a conventional color filter can also be omitted from the LCD according to the disclosed embodiments. Accordingly, devices made with the LCDs described herein can be thinner and lighter than conventional LCD devices.
Furthermore, some embodiments use a UV light source instead of a white light source which is used in conventional LCDs. Energy efficiency can be improved by using UV light instead of white light, because with white light, energy loss occurs when certain color components of white light are absorbed during the color filtering process. In some embodiments, a UV light source that emits three primary colors can be used.
Referring to
In some embodiments, the light source 280 is a UV light source 280 as opposed to a white light source 180 which is used in conventional LCDs 100. Because color filters 120 produce color by absorbing certain color components and emitting others, energy loss occurs when certain color components of white light are absorbed. In contrast, by using a UV light source 280 emitted in three primary colors, the LCDs 200 according to the some embodiments improve energy efficiency.
In some embodiments, the layer of transparent fluorescent films 250 can include a plurality of red transparent fluorescent films 310, a plurality of green transparent fluorescent films 320, and a plurality of blue transparent fluorescent films 330. Referring to
The red, green, and blue transparent fluorescent films 310, 320, 330 can be made of a material that emits each respective color light when excited by UV light. Thus, when light from the UV light source 280 (shown in
In some embodiments, the transparent resin has high permittivity so that stable electric fields can be applied to the LCD 200.
The material of the red transparent fluorescent film 310 can include a complex in which tri-n-butyl phosphate and thenoyltrifluoroacetone are coordinated with europium (Eu3+), as shown by formula (1) below.
Thenoyltrifluoroacetone can be present in the complex in an amount of about 0.1% to about 50% by weight, such as about 0.1%, 10%, 20%, 30%, 40%, 50%, or an amount in between any of these values by weight. For example, the complex can have about 24% thenoyltrifluoroacetone by weight. In some embodiments, the material of a green transparent fluorescent film 320 can include a complex in which 1,10-phenanthroline and a β diketone are coordinated with terbium (Tb3+). Examples of β diketone include acetylacetone, trifluoroacetylacetone, and hexafluoroacetylacetone. In other embodiments, the material of the green transparent fluorescent film can include a complex in which phenylpyridine is coordinated with iridium (Ir3+). The material of the blue transparent film 330 can include a fluorescent brightening agent, such as a derivative of bis(triazinylamino), a derivative of bis-strylbiphenyl, or 2,5-bis(5-tert-butly-2-benzoxazolyl) thiophen. These materials for the red, green, and blue transparent fluorescent films 310, 320, 330 can emit each respective color light when excited by UV light. In some embodiments, the complexes of the red, blue, and green films can be made by chemical synthesis.
In some embodiments, step 430 (forming a layer of transparent fluorescent films 250 on a TFT array substrate 260) may be repeated for red, green, and blue transparent fluorescent films 310, 320, 330, on different subsets of pixels on the TFT array substrate 260. In some embodiments, the TFT array substrate 260 can be a substrate on which a TFT array is already formed. In other embodiments, the TFT array substrate 260 can be a substrate on which a TFT array will be formed. Thus, the layer of transparent fluorescent films 250 can be formed on the TFT array substrate 260 before or after the TFT array is formed on the substrate 260.
Still referring to
In some embodiments, the red, green and blue transparent fluorescent materials can be obtained commercially. For example, Examples 2 and 3 below describe commercially obtained green and blue transparent fluorescent materials, respectively. In some embodiments, the red transparent fluorescent material can be prepared according to the method illustrated in
Referring to
The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
In a glass vessel, 12 grams of concentrated nitric acid (with a concentration, of 60% and a specific gravity of 1.38) was added to 6 grams of europium oxide. Due to the heat from the reaction of the nitric acid with the europium oxide, europium oxide was dissolved, yielding an aqueous solution of europium nitrate.
Tri-n-butyl phosphate (27 grams) and hexane (30 grams) were added to the aqueous solution of europium nitrate. The resulting solution was shaken vigorously for one minute to extract europium ions from the liquid phase to the organic phase. Next, the hexane was evaporated and removed from the solution by using an evaporator, yielding a transparent liquid composition in which tri-n-butylphosphate was coordinated with the europium ions.
Next, thenoyltrifluoroacetone was added to this composition in which tri-n-butylphosphate was coordinated with the europium ions, yielding a europium(Eu3+) tri-n-butyl phosphate and thenoyltrifluoroacetone complex, as shown by formula (1) above.
Six samples of the europium (Eu3+) tri-n-butyl phosphate and thenoyltrifluoroacetone complex were prepared, each with a different amount of thenoyltrifluoroacetane. The percentages of thenoyltrifluoroacetane in the six samples were 0.35%, 0.75%, 1.00%, 1.80%, 2.50%, and 24.0% by weight, respectively. The amount of ultraviolet light absorbed by the six samples was measured. The results are illustrated in
Each of the six samples was added to an acrylic-resin-based ink for screen printing (Super Gloss Ink 100, Jujo Chemical, Tokyo, Japan), in an amount corresponding to 10% resin by weight. The resulting solution was applied to a glass substrate, which was dried to form a red transparent fluorescent film having a thickness of 25 μm. Thus, six glass substrates, each having a red transparent fluorescent film with a different amount of thenoyltrifluoroacetane, were produced. The light excitation and emission spectra were measured for each of the six glass substrates having a red transparent fluorescent film.
The resulting substrates with the red transparent fluorescent films formed thereon were effective in emitting red light when ultraviolet light was projected onto the substrate as can be seen from
green transparent fluorescent material (Green 520 (triazoles or oxadiazoles), Harima Chemicals, Inc., Tokyo, Japan was added to a toluene solution, in an amount corresponding to 2% of the green transparent fluorescent material by weight. The toluene solution containing the green transparent fluorescent material was added to an acrylic-resin-based ink for screen printing (Super Gloss Ink 100, Jujo Chemical, Tokyo, Japan), in an amount corresponding to 10% resin by weight. The resulting composition was applied to a glass substrate, which was dried to form a green transparent fluorescent film having a thickness of 25 μm.
The light excitation and emission spectra were measured for the substrate having the green transparent fluorescent film.
blue transparent fluorescent film was formed on a glass substrate in the same manner as in Example 2, except that instead of a green transparent fluorescent material, a blue transparent fluorescent material (Tinopal OB (2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)), Ciba, Basel, Switzerland) was added to a toluene solution. The blue transparent fluorescent material is represented by the compound illustrated in formula (2).
The light excitation and emission spectra were measured for the substrate having a blue transparent fluorescent film.
red transparent fluorescent ink was prepared in the same manner described in Example 1. The europium (Eu3−) tri-n-butyl phosphate and thenoyltrifluoroacetone complex contained 24% thenoyltrifluoroacetone by weight.
A green ink was prepared by adding a green transparent fluorescent material (Green 520 (triazoles or oxadiazoles), Harima Chemicals) to a tri-n-butylphosphate solution. A tri-n-butylphosphate solution was chosen because the green ink was to be applied by ink-jet printing, and a tri-n-butylphosphate solution would minimize the chances of clogging up the ink-jet nozzle. The tri-n-butylphosphate solution containing the green transparent fluorescent material was added to a transparent resin based ink. The resulting green transparent fluorescent ink contained 1.88% of the green fluorescent transparent material by weight.
A blue ink was prepared by adding a blue transparent fluorescent material (Tinopal OB (2,5-thiophenediylbis(5-tert-butyl-1,3-benzoxazole)), Ciba) to a tri-n-butyl-phosphate solution. A tri-n-butylphosphate solution was chosen because the blue ink was to be applied by ink-jet printing, and a tri-n-butylphosphate solution would minimize the chances of clogging up the ink-jet nozzle. The tri-n-butylphosphate solution containing the blue transparent fluorescent material was added to a transparent resin based ink. The resulting blue transparent fluorescent ink contained 0.68% of the blue transparent fluorescent material by weight.
The red, green, and blue fluorescent inks were applied to an acrylic substrate by ink-jet printing in a mosaic pattern with uniform area ratios. The acrylic substrate was a UV-transparent poly-methacrylate cast board having a size of 100 mm×100 mm and a thickness of 5 mm (Paraglass UV00, Kuraray, Tokyo, Japan). The fluorescent inks were dried, thus forming fluorescent films on the acrylic substrate. An ultraviolet LED lamp (NS375L-3RLQ, Nitride Semiconductor Co., Ltd., Tokushima, Japan) was installed at an edge of the acrylic substrate. When the ultraviolet LED lamp emitted light, intense white light emission, which included blue, green, and red emission, was achieved. The resulting emission spectrum is illustrated in
A TFT array was formed on the acrylic substrate with the fluorescent films. In addition, an ITO (indium tin oxide) layer was formed on the acrylic substrate. A polarizer was disposed on top of the fluorescent films formed on the acrylic substrate. A UV light source was disposed at an edge of the acrylic substrate and a reflecting sheet was disposed at the bottom of the acrylic substrate opposite the side of the substrate having the fluorescent films. An ITO layer was formed on a second substrate. A second polarizer was disposed on top of the second substrate. A spacer was placed between the bottom of the second substrate and the polarizer on top of the first acrylic substrate. A liquid crystal layer was inserted in the space created by the spacer.
Light was projected from the UV light source and through the acrylic substrate, which had a layer of transparent fluorescent films and a TFT array formed thereon. The UV light was incident on the fluorescent films, thus exciting the fluorescent films and causing them to emit red, green, and blue colors. Therefore, it can be shown that the LCD in accordance with the disclosed embodiments can emit the respective colored lights without the need for a color filter. Also, as the UV light projected directly through the TFT array, there is no need for a light guide plate like in conventional LCDs.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (for example, bodies of the appended claims) are generally intended as “open” terms (for example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” and so on). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (for example, “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (for example, the bare recitation of “two recitations,” without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, and so on” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, and so on). In those instances where a convention analogous to “at least one of A, B, or C, and so on” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (for example, “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, and so on). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, and so on. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, and so on. As will also be understood by one skilled in the art all language such as “up to,” “at least,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.
From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US14/20275 | 3/4/2014 | WO | 00 |
