CN101021587A - Method for producing choles phase liquid crystal high-molecular optical reinforced film - Google Patents
Method for producing choles phase liquid crystal high-molecular optical reinforced film Download PDFInfo
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- CN101021587A CN101021587A CN 200710064891 CN200710064891A CN101021587A CN 101021587 A CN101021587 A CN 101021587A CN 200710064891 CN200710064891 CN 200710064891 CN 200710064891 A CN200710064891 A CN 200710064891A CN 101021587 A CN101021587 A CN 101021587A
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Abstract
The invention is a cholesteric liquid crystal high molecular light intensifying film preparing method, belonging to the field of LCD light intensifying film technique. And the process: liquid crystal high molecules placed in between two transparent plastic films and shows in cholesteric phase between glass transition temperature and 280 deg.C, are made into thin film in the liquid crystal-phase temperature range in the rolling mode, heating the liquid crystal high molecular film to temperature T so that cholesteric liquid crystal molecules form plane structured molecular arrangement mode, then placing the thin film on a temperature control table with temperature T1, keeping the spatial temperature of the outer surface of the upper transparent plastic film be equal to T2, cooling so that the cholesteric liquid crystal high molecular film forms pitch gradient in the direction vertical to the surfaces of the two transparent plastic films; and the pitch gradient is frozen in the glass state of the cholesteric liquid crystal high molecules. And its advantages: the selected material system and the making process are simple and convenient, and the optical performance is excellent.
Description
Technical field
The invention belongs to LCD optical reinforced film technical field, relate to a kind of preparation method of choles phase liquid crystal high-molecular optical reinforced film, easy, the excellent in optical properties of preparation technology.
Background technology
The backlight technology is one of TFT-LCD core technology, accounts for 25%～35% (notebook display screen: about 25% of TFT-LCD total cost; TV display screen: 30%～35%).And optical reinforced film accounts for 30%～40% of back light source system cost.People have proposed requirements at the higher level to the low-power consumption of LCD, long-time standby at present.As everyone knows, liquid crystal self can be not luminous, and it is luminous to need the backlight support, and the height of LCD brightness affects the quality of image to a certain extent.Very high (the LCDs power consumption of notebook is about 6.5W but back light system accounts for the power consumption proportion of whole main frame, wherein the power consumption of back light source system is about 5W, the driving power consumption of display screen is about 1.5W), increase the non-wise move of brightness of backlight itself, use optical reinforced film to become one of requisite measure.Optical reinforced film can make all kinds of LCD brighter, more bright-coloured, and is thinner and more energy-conservation.
The optical reinforced film technology is mainly monopolized by offshore companies such as Minnesota Mining and Manufacturing Company.The polaroid of traditional LCD adopts two tropism's dyestuffs.This dyestuff is many strongly to the absorption of the polarized light of its vertical direction to a kind of absorptance of polarized light of direction.The highest light transmission rate of this absorptive-type polaroid only 50% in fact often has only more than 40%.This is 4～6% the one of the main reasons that the brightness of conventional liquid crystal has only light source.Low efficient like this, not only display brightness is low, has increased the consumption of electric energy, limits its portability, and has influenced display visuality out of doors.
The basis of optical reinforced film is non-absorption-type polaroid.It allows a kind of polarized light to see through, and another kind of polarized light on the other side is reflected, rather than is absorbed.The polarized light that is reflected is by handling, and this polaroid that can lead once more is so some light passes through again.So circulation just can make full use of all incident raies.Optical reinforced film mainly contains the cycle duplicature optical reinforced film of 3M company and the products such as choles phase liquid crystal high-molecular optical reinforced film of Merck ﹠ Co., Inc. in the market.Technology is all monopolized by offshore company.
As the cycle duplicature optical reinforced film of one of 3M company invention of great significance technology, manufacturing process more complicated.At first be two kinds of macromolecule membranes alternately to be squeezed into reach hundreds of layers, and thickness only have the film of about 400～550um.Uniaxial tension technology by 3M stretches along a certain direction in the face, and wherein a kind of film is changed in the refractive index of this direction, thereby forms this direction refractive index alternate and the constant substantially membraneous material of its vertical direction refractive index; For making its reach cover whole visible light wave range, the thickness of each layer of macromolecule membrane also will change gradually along with its thickness direction.When a branch of nonpolarized light incident, a kind of linear polarization light transmission, another kind of linearly polarized photon is reflected.The linearly polarized photon of returning that is reflected runs into after the light guide plate, is reflected again after being depolarized.In the reciprocal incident of polaroid cocycle, the light utilization of final this polaroid can reach about 75% by light, makes the final brightness of LCD increase about 60%.
The Holland scientist utilizes liquid crystal material of cholesteric phase successfully to develop choles phase liquid crystal high-molecular optical reinforced film, forms the Transmax film of Merck ﹠ Co., Inc..Liquid crystal material of cholesteric phase has the characteristics of the reflection selected to circularly polarized light, can reflect back the circularly polarized light of the polarization direction identical with its pitch sense of rotation and allows the circularly polarized light of opposite polarization to see through.The wavelength coverage of single pitch cholesteric liquid crystal selective reflecting incident light is between λ
Min=Pn
oAnd λ
Max=Pn
eBetween (n wherein
oAnd n
eBe respectively ordinary light and extraordinary ray refractive index); Reflection spectrum bandwidth Δ λ is Δ λ=λ
Max-λ
Min=(n
e-n
o) P=Δ nP (Δ n=n wherein
e-n
oBe birefraction).Outside reflection spectrum bandwidth, two kinds of circularly polarized lights are all by transmissive.For example, when the helical structure of liquid crystal material of cholesteric phase when being left-handed, it reflects back left circularly polarized light and allows the right-hand circular polarization light transmission.Left circularly polarized light then can change linearly polarized photon into after through a quarter wave plate.If the left circularly polarized light that reflects is reflected back by a minute surface again, it will become right-circularly polarized light.So move in circles, the light utilization of final this polaroid can reach 75%～80%, even higher.Because the Δ n that does not have the color organic compound is less than 0.3, so the reflectance spectrum of the cholesteric liquid crystal of single pitch is subjected to the restriction of liquid crystal birefringence rate often to have only tens nanometers.Therefore need the pitch of cholesteric liquid crystal to gradually change, just might make the reflectance spectrum of cholesteric liquid crystal cover visible light wave range, also just might be prepared into practical non-absorption-type polaroid along its thickness direction.Concrete preparation method is (D.J.Broer, J.Lub, and G.N.Mol, Nature, 378,467,1995):
Chirality liquid crystal liquid crystal property photo polymerization monomer/photo polymerization monomer/light trigger/colorant mixture is clipped in the two-layer transparent plastic film, and the film inside surface will pass through parallel-oriented processing in advance, causes the photo polymerization monomer polymerization with the UV-irradiation film then.Because have pigment to exist, ultraviolet ray intensity forms graded in film, stronger near ultraviolet ray intensity in the ultraviolet light one side film, an opposite side a little less than.In the stronger side of ultraviolet ray intensity, intermolecular cross-linking reaction more easily takes place in photo polymerization monomer, and photo polymerization monomer concentration is low than the more weak side of ultraviolet ray intensity, and polymerization single polymerization monomer is then by the stronger side diffusion of the more weak side direction of ultraviolet ray intensity.So in the strong and low side of ultraviolet ray intensity, the pitch of liquid crystal molecule helical arrangement is less and bigger respectively in the film, pitch gradually changes along its thickness direction, and the light reflecting thin film spectrum covers visible light wave range.
Compare with the double-deck reinforcing membrane of the VIKUITI of 3M company, the advantage that the Transmax film of Merck ﹠ Co., Inc. may have is as follows:
| Item compared | 3M?VIKUITI | The Transmax of Merck ﹠ Co., Inc. is thin |
| Technology | Complexity reaches the hundreds of layer film, and the thickness evenness of each floor height molecular film and the stability at interface are huge challenges | Simply, has only one deck |
| Cost | High | Low (the former about 3/5) |
| Light transmission rate | 75%, need prism film | 75%～80%, do not need prism film |
| Processing characteristics | Be difficult to be prepared into large tracts of land | Be easy to be prepared into large tracts of land |
But the Transmax film of Merck ﹠ Co., Inc. need carry out parallel-oriented processing and the intensity distributions of strict control ultraviolet light in thin layer, therefore processing technology more complicated in preparation process to the film inside surface in preparation process.
Summary of the invention
The object of the present invention is to provide a kind of preparation method of choles phase liquid crystal high-molecular optical reinforced film, solve the loaded down with trivial details problem of technology of preparation choles phase liquid crystal high-molecular optical reinforced film.
Preparation technology of the present invention is:
Be clipped in inside surface and do not pass through in the middle of the two-layer transparent plastic film of orientation process with the raise liquid crystal polymer that increases and glass microballoon of temperature being the pitch that is cholesteric phase and cholesteric liquid crystal molecule between the glassy state, glass transition temperature to 280 ℃ under the room temperature, adopt the roll-in mode to be prepared into film in being the temperature range of liquid crystal phase, the thickness of liquid crystal polymer film is by the size decision of glass microballoon.In being the temperature range of liquid crystal phase film is heated to temperature T then, increases because the pitch of cholesteric liquid crystal molecule raises with temperature, along with temperature raises, the cholesteric liquid crystal molecule forms the molecules align mode of planar texture.Then film is placed on the temperature control platform that temperature is T1, keeping the space temperature above the film is T2, and T1 and T2 place temperature range are between the glass transition temperature of-50 ℃ and choles phase liquid crystal high-molecular.Because the environment temperature difference that outside surface contacted of transparent plastic film up and down, be clipped in the temperature difference of the levels part of the choles phase liquid crystal high-molecular film in the transparent plastic film after the cooling, also mean the cooling rate difference of the levels part of liquid crystal polymer film, the cooling rate of the underclad portion of choles phase liquid crystal high-molecular film is faster than the cooling rate of top section.The top section of choles phase liquid crystal high-molecular film is followed than underclad portion and is compared like this, and the molecule of choles phase liquid crystal high-molecular film has that the time resets more fully.That is to say with the top section of choles phase liquid crystal high-molecular film and compare easier being frozen in the glassy state of molecules align state of the underclad portion of choles phase liquid crystal high-molecular film.Like this, on the direction on vertical two-layer transparent plastic film surface, the pitch of choles phase liquid crystal high-molecular film increases from top to bottom gradually, forms pitch gradient.And this pitch gradient is frozen in the glassy state of choles phase liquid crystal high-molecular.This moment, the choles phase liquid crystal high-molecular film can the very wide circularly polarized incident light of reflected wavelength range, prepared the optical reinforced film that successfully can be used for LCD.
Choles phase liquid crystal high-molecular of the present invention has and at room temperature is the feature that the pitch that is cholesteric phase and cholesteric liquid crystal molecule between the glassy state, glass transition temperature to 280 ℃ raises and increases with temperature.Choles phase liquid crystal high-molecular can be backbone chain type or side chain type liquid crystal macromolecule.If the side chain type liquid crystal macromolecule, its backbone structure can be ring-like, also can be linear structure.
Choles phase liquid crystal high-molecular of the present invention can also use other chirality or achirality macromolecule or micromolecule liquid crystal (or non-liquid crystal liquid crystal property chirality or achirality macromolecule or micromolecule organic compound) to mix and adjust pitch size and phase transition temperature.
The inside surface of transparent plastic film used in the present invention can be not through parallel-oriented processing or through parallel-oriented processing.
Description of drawings
Fig. 1 is the molecular structure and the phase transition temperature of employed choles phase liquid crystal high-molecular.
Transmission spectrum curve when Fig. 2 is employed choles phase liquid crystal high-molecular different temperatures.
Fig. 3 is the simulation drawing of the principle of the optical reinforced film of preparation.
Fig. 4 is the electron scanning micrograph of prepared choles phase liquid crystal high-molecular thin-membrane section.
Fig. 5 is the relation curve of the light transmission of prepared choles phase liquid crystal high-molecular film with wavelength variations.
Embodiment
Embodiment 1:
Employed choles phase liquid crystal high-molecular as shown in Figure 1.
Fig. 2 is the transmission spectrum curve during employed choles phase liquid crystal high-molecular different temperatures among the present invention.As can be seen from the figure, the minimum transmittance wavelength (reflection wavelength) of choles phase liquid crystal high-molecular raises with temperature and increases, so raising with temperature of the pitch of choles phase liquid crystal high-molecular liquid crystal phase increases.
Fig. 3 is the simulation drawing of the principle of preparation optical reinforced film.With employed choles phase liquid crystal high-molecular and diameter is that 20 microns glass microballoon mixes, being clipped in inside surface does not then pass through in the middle of the two-layer transparent plastic film of orientation process, in being the temperature range of liquid crystal phase, adopt the roll-in mode to be prepared into film, shown in Fig. 3 (a).Then with 5Kmin
-1Programming rate film is heated to 396.2K increase because the pitch of cholesteric liquid crystal molecule raises with temperature, after film was heated to 396.2K, the cholesteric liquid crystal molecule formed the molecules align mode of planar texture, shown in Fig. 3 (b).Then film is placed on the temperature control platform that temperature is 273.2K, keeping the space temperature above the film is 299.2K.Because the environment temperature difference that transparent plastic film contacted up and down, be clipped in the temperature difference of the top and the bottom of the choles phase liquid crystal high-molecular film in the transparent plastic film after the cooling, also mean the cooling rate difference of the top and the bottom of choles phase liquid crystal high-molecular film, the cooling rate of the underclad portion of choles phase liquid crystal high-molecular film is faster than the cooling rate of top section.The top section of choles phase liquid crystal high-molecular film is followed than underclad portion and is compared like this, and the molecule of choles phase liquid crystal high-molecular film has that the time resets more fully.That is to say with the top section of choles phase liquid crystal high-molecular film and compare easier being frozen in the glassy state of molecules align state of the underclad portion of choles phase liquid crystal high-molecular film.Like this, on the direction on vertical two-layer transparent plastic film surface, the pitch of choles phase liquid crystal high-molecular film increases from top to bottom gradually, and the pitch gradient of formation is shown in Fig. 3 (c).
Fig. 4 is the electromicroscopic photograph of thin-membrane section.As can be seen from the figure, on the direction on vertical two-layer transparent plastic film surface, the pitch of choles phase liquid crystal high-molecular film is to increase gradually from top to bottom really, the pitch gradient of formation.
Fig. 5 is the transmitance (therefrom can judge reflectivity) of the prepared choles phase liquid crystal high-molecular film relation curve with wavelength variations.As can be seen from the figure, the choles phase liquid crystal high-molecular film can the very wide circularly polarized incident light of reflected wavelength range.Regulate fabrication process condition, the choles phase liquid crystal high-molecular film can reflected wavelength range be the circularly polarized incident light of 400nm-750nm.So can prepare the optical reinforced film that is used for LCD by said method.
Claims (5)
1, a kind of preparation method of choles phase liquid crystal high-molecular optical reinforced film, it is characterized in that, technology is: will be clipped in the liquid crystal polymer that is cholesteric phase between the glass transition temperature to 280 ℃ between two-layer transparent plastic film and adopt the roll-in mode to be prepared into film in being the temperature range of liquid crystal phase, liquid crystal polymer film is heated to temperature T, the cholesteric liquid crystal molecule forms the molecules align mode of planar texture, then film is placed on the temperature control platform that temperature is T1, keeping the space temperature of upper strata transparent plastic film outside surface is T2, and T1 and T2 place temperature range are between the glass transition temperature of-50 ℃ and choles phase liquid crystal high-molecular; After above-mentioned condition cooling, on the direction on vertical two-layer transparent plastic film surface, the choles phase liquid crystal high-molecular film forms pitch gradient; And this pitch gradient is frozen in the glassy state of choles phase liquid crystal high-molecular.
2, method according to claim 1 is characterized in that: the inside surface of transparent plastic film can be without parallel-oriented processing or through parallel-oriented processing.
3, method according to claim 1 is characterized in that: liquid crystal polymer at room temperature is the pitch that is cholesteric phase and choles phase liquid crystal high-molecular between the glassy state, glass transition temperature to 280 ℃ and raises with temperature and increase.
4, method according to claim 1 is characterized in that: liquid crystal polymer is backbone chain type or side chain type liquid crystal macromolecule; If the side chain type liquid crystal macromolecule, its backbone structure is ring-like or linear structure.
5, method according to claim 3, it is characterized in that choles phase liquid crystal high-molecular uses other chirality or achirality macromolecule or micromolecule liquid crystal or non-liquid crystal liquid crystal property chirality or achirality macromolecule or micromolecule organic compound to mix and adjusts pitch size and phase transition temperature.
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| CN 200710064891 CN101021587A (en) | 2007-03-28 | 2007-03-28 | Method for producing choles phase liquid crystal high-molecular optical reinforced film |
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| CN 200710064891 CN101021587A (en) | 2007-03-28 | 2007-03-28 | Method for producing choles phase liquid crystal high-molecular optical reinforced film |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106317423A (en) * | 2016-08-22 | 2017-01-11 | 青岛科技大学 | Method for regulating pitch of cellulose lyotopic cholesteric liquid crystals by using chiral substances |
| CN106997127A (en) * | 2017-04-21 | 2017-08-01 | 深圳市屏柔科技有限公司 | A kind of thick person's handwriting pressure sensitive cholesteric liquid crystal blackboard structure of high brightness and manufacture craft |
| CN111429792A (en) * | 2020-04-27 | 2020-07-17 | 北京智慧港教育咨询有限公司 | Preparation method of block chain anti-counterfeiting traceability polymer liquid crystal optical film |
| CN113391492A (en) * | 2021-06-23 | 2021-09-14 | 北京科技大学 | Near-infrared light shielding film material, preparation method and application |
-
2007
- 2007-03-28 CN CN 200710064891 patent/CN101021587A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106317423A (en) * | 2016-08-22 | 2017-01-11 | 青岛科技大学 | Method for regulating pitch of cellulose lyotopic cholesteric liquid crystals by using chiral substances |
| CN106317423B (en) * | 2016-08-22 | 2019-05-17 | 青岛科技大学 | A kind of method that chiral material adjusts the molten cause cholesteric liquid crystal screw pitch of cellulose |
| CN106997127A (en) * | 2017-04-21 | 2017-08-01 | 深圳市屏柔科技有限公司 | A kind of thick person's handwriting pressure sensitive cholesteric liquid crystal blackboard structure of high brightness and manufacture craft |
| CN111429792A (en) * | 2020-04-27 | 2020-07-17 | 北京智慧港教育咨询有限公司 | Preparation method of block chain anti-counterfeiting traceability polymer liquid crystal optical film |
| CN113391492A (en) * | 2021-06-23 | 2021-09-14 | 北京科技大学 | Near-infrared light shielding film material, preparation method and application |
| CN113391492B (en) * | 2021-06-23 | 2022-03-22 | 北京科技大学 | Near-infrared light shielding film material, preparation method and application |
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