Patent Application
20050207008
1. Field of the Invention
The present invention relates to a structure and generated method of a polarizer, and more particularly to a structure and a generated method with a polarizer to improve the view angle of a display.
2. Description of the Prior Art
Polarizer is also known as polarizing film, which polarizes the light from a non-polarized light to a polarized light, therefore; a polarized light is formed. Producing the polarized light is utilized the ways as following: (a) utilizing the specific materials with the characteristic of dichroism such as Iodine compounds or dye; (b) utilizing the species having the character of birefringence such as Nicol spar or Glan-Thiomson crystal etc.; (c) utilizing the reflectivity and refractivity between the interfaces of the two species that stacked a few transparent films (such as glass) having different thickness, so the light beam will be filtered layer by layer when it is incident toward to the transparent films with a suitable angle. Thus, the output light beam has the definite extinction ratio, and a partially polarized light is obtained.
Typically, the polarizing film is divided into absorbed type and reflective type, and absorbed type is further divided into O type, E type, dye type and Iodine type polarizing film. The dye type and Iodine type utilize the Iodine ion (I3− and I5−) permeated into a polymer film such as polyvinyl alcohol (PVA). By Iodine ion or dye molecules have regular ordination thereof, the polymer film can absorb the light vector, which is parallel to the direction of Iodine so that the light vector, which is perpendicular, is passed through. Hence, a polarizing film with the character for polarizing the light is produced. Normally, TFT-LCD has the dye type or Iodine type polarizing film. It notes that a protective film such as triacetyl-cellulose (TAC) is formed respectively on two sides of the PVA film, which is extended to several millimeters. Consequently, the PVA film and TAC films constitute a structure of polarizing film having a sandwich like structure.
The phenomenon of polarization is common to apply in the liquid crystal display (LCD) such as laptop, desktop, PDA, cell phone, etc. The polarizing film acts as a filter to the light. When the voltage is not applied, the liquid crystal molecules are arranged to 90° that associates with the order of the coordination film placed on the upward polarizing film and downward polarizing film respectively. The polarized light is formed after the light beam is passed through the downward polarizing film, moreover; because of the optical anisotropy of the liquid crystal molecules, the polarized light is passed through the upward polarizing film along the liquid crystal molecules, which are twisted to 90°. Hence, the LCD will be “light”. However, after the voltage is applied, the liquid crystal molecules having the twist of 90° have become perpendicular in the order, so that the polarized light passes through the downward polarizing film in the original direction, and the upward polarizing film is shielded. Therefore, the LCD is “dark”. According to the principle thereon, the appearance of LCD can be controlled to be light or dark.
The LCD device has become popular nowadays, however; it has some technologies that need to be improved, such as the limitation in view angle, the response time and brightness. The principle of LCD is that utilizes the liquid crystal molecules to twist the direction of polarized light and the character of double refraction to achieve the purpose of light/dark. However, the LCD naturally has a problem with the view angle. The quality of display depends on where the viewer is, and the contrast ratio has become lower when the view angle is getting bigger. Hence, following the maximized development in the LCD apparatus, the technology of wide-viewing angle (WVA) is becoming important.
In addition, the protective films 105/105′, such as TAC film, cellulose aceto butyrate (CAB) layer and acrylic resin layer, are formed on two sides of the polymer film 103/103′ respectively within the upward polarizing film 101 and downward polarizing film 101′. The protective films 105/105′ in the upward polarizing film 101 and downward polarizing film 101′ are utilized to protect the polymer film 103/103′ from damage of moisture, heat and mechanism. Besides, the protective films need the character of high transparency to prevent the interference from the polarized light.
Next, a structure with the upward polarizing film 101 and downward polarizing film 101′ is applied within a LCD apparatus. The LCD apparatus comprises a LC cell 107, an upward polarizing film 101 and a downward polarizing film 101′, wherein the LC cell 107 comprises a plurality of liquid crystal molecules such as a twisted nematic (TN) liquid crystal molecules. In addition, the upward polarizing film 101 is placed to 90° with the downward polarizing film 101′, and the liquid crystal molecules within the LC cell 107 are also twisted and being parallel in order thereof. Because of the optical anisotropy, the light beam without polarization will be polarized to the polarized light after passing through the downward polarizing film 101′. Moreover, the polarized light will go along with the liquid crystal molecules within the LC cell 107, and arrive to the upward polarizing film 101. However, when a voltage is applied to the LCD apparatus, the liquid crystal molecules within the LC cell 107 will become perpendicular in ordination, and being identical with the direction of the polarized light passed through the downward polarized film 101′. Due to the fact that the upward polarizing film 101 and downward polarizing film are placed to 90°, the polarized light can not pass though the upward polarizing film 101 from the downward polarizing film 101′. According to the theory mentioned above, controlling the direction of the rotation in the liquid crystal molecules through the voltage can alter the statement of light/dark on the LCD apparatus.
To make the liquid crystal molecules are placed in order on the upward polarizing film 101 and downward polarizing film 101′, the upward polarizing film 101 and downward polarizing film 101′ have to perform the rubbing process. By the rubbing process, the control of the liquid crystal molecules are disposed in a unique direction within a unique area, wherein the treatment of orientation on the surface of the upward polarizing film 101 and downward polarizing film 101′ is performed to form a coordination film (not shown in the figure). The coordination film exists a van der waals interaction, dipole-dipole interaction and hydrogen bond etc. to make the liquid crystal molecules be successivein order.
After applying the voltage to the LCD apparatus, the liquid crystal molecules nearby and the upward polarizing film 101 and downward polarizing film 101′ can not be perpendicular in order because of the effect from the rubbing on the polarizing film. It means that will produce a pretilt angle so that a number of polarized lights can pass through the liquid crystal molecules and arrive to the upward polarizing film 101. Hence, the viewer will observe the illuminated points when the statement is “dark” that is to say, it is a statement of light leakage in the dark. As a result, the contrast ratio of a display is definite as light brightness divided by dark brightness, the phenomenon of light leakage in the dark will directly influence the dark brightness of LCD apparatus, and further influence the contrast ration of an LCD apparatus. Therefore, the phenomenon of light leakage in the dark will influence the view angle of the LCD apparatus, that is one of the reasons for an improper view angle of the LCD apparatus.
In addition, the polymer films 103/103′ comprise a plurality of dichroism materials; nevertheless, the dichroism materials such as Iodine ion emit a light with a specific wavelength under the dark statement after applying the voltage. By a real observation, the wavelength is about 400 μm that causes the phenomenon of light leakage in the dark, which influences the dark brightness and contrast ratio of the LCD apparatus, and further to influence the view angle of the LCD apparatus. That is to say, it is one of the reasons for an improper view angle in the display apparatus.
As the above-mentioned description, the liquid crystal molecules will generate the pre-tilt angle and the Iodine ion will emit the light having a specific wavelength, both of which influence the dark brightness of the LCD after applying the voltage to a display apparatus. The problem thereon prevents the display apparatus from obtaining the proper view angle. To solve the problem thereof, the present invention provides a polarizer to improve the problem with an insufficient view angle in the display apparatus.
It is an objective of the present invention to provide a structure and generated a method of a polarizer, wherein a black dye layer is added in the polarizer to effectively reduce the dark brightness of a display apparatus and enhance the contrast ration of a display apparatus.
It is another objective of the present invention to provide a structure and a generated method of a polarizer, wherein a black dye layer is mixed with an optical film in the polarizer to absorb the light emitted from the dichroism materials in the polymer film and enhance the view angle of a display apparatus.
It is further objective of the present invention to provide a black dye, and utilizing the simple and convenient process to achieve the purpose with improving the view angle of a display apparatus.
In order to achieve the objects as mentioned above, the present invention provides a polarizer for improving the view angle, which comprises a polymer film, a plurality of protective films and at least a black dye layer. The plurality of protective layers is placed on the upside and downside of the polymer film respectively, which comprises a plurality of dichroism materials such as Iodine ion. Also, the black dye layer is placed on the surface of one of the protective films that absorbs the light emitted from the plurality of dichrosim materials. The black dye layer comprises a black dye and a thermal resin, and the thickness of the black layer depends on the desirable saturation of absorbency. By the polarizer of the present invention, the dark brightness of the display apparatus is effectively reduced, and the contrast ration is improved. Hence, the view angle of the display apparatus is enhanced.
The above-mentioned polarizer can also utilize the black dye layer mixes with an optical film layer such as an anti-glare layer or an anti-reflection layer to form a mixed layer on the protective layers.
The objectives and features of the present inventions as well as advantages thereof will become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings, which are not to scale, are designed for the purpose of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.
The present invention can be best understood through the following description and accompanying drawings, wherein:
The present invention provides a structure and generated method of a polarizer that firstly forms a polymer film comprising a plurality of dichroism materials such as Iodine ion therein. Next, the protective films are formed on the upside and downside of the polymer film respectively. Then, at least one layer of the black dye layer is formed on the surface of one of the protective films, wherein the black dye layer comprises a black dye and a thermal resin therein. After that, at least an optical layer is formed on the surface of the black dye layer. Moreover, the polarizer of the present invention can be applied into a display apparatus.
Preferred embodiments of this invention will be explained with reference to the drawings of
As a result, the mechanical property of the polymer film 201 will be reduced and become easily breakable after stretching the polymer film 201. Hence, the protective films 203, such as TAC film, are formed on the upside and downside of the polymer 201 to support and protect the polymer film 201 and prevent the polymer film from shrinking. Because of the high moisture permeability, the protective films 203 are utilized to protect the polymer film 201, therefore; the polymer film 201 can prevent the damage of moisture and high temperature. Also, the protective films 203 need to have the properties with durability and high transparency to avoid interfering with polarization. Subsequently, the protective films 203 are adhered with the polymer film 201 through an adhesive layer, which is sensitive to pressure. The adhesive layer can be polyacrylate.
Next, at least one black dye layer 205 is formed on one of the protective films 203 to absorb the light emitted from the dichrosim materials within polymer film 201 that reduces the dark brightness. Hence, the contrast ratio of the display apparatus is enhanced, and the view angle is further improved. The black dye layer 205 has an adhesion that utilizes a black dye mixed with a resin through a solvent, wherein the resin is a thermal resin and the solvent is ethanol. After the solvent evaporates, the black dye layer 205 is completely adhered with the protective films 203. In addition, the black dye layer 205 has the property of saturation for absorbing the light so that the thickness of the black dye layer 205 can be utilized to decide the desirable saturation. Furthermore, the black dye layer 205 needs to have the proper transparency for light.
Then, a first optical layer 207 is formed on the black dye layer 205 such as an anti-reflection layer that can reduce the interference with the light from outside, and further improve the light transparency and contrast ratio. Moreover, the first optical film 203 also needs to have the proper characteristics with transparency, hardness, adhesion, thermal endurance and durability. After forming the first optical layer 207, a second optical layer 209 is formed on the surface of the first optical layer 207, such as an anti-glare layer, to reduce the reflection from outside. The second optical layer 209 is utilizes an appropriate method, such as sandblasting, embossing or blending a plurality of transparent particles to form an aspirate surface to achieve the effect of anti-glaring. Finally, the polarizer of present invention is accomplished.
Another preferred embodiment of this invention will be explained with reference to the drawings of
It notes that the black dye layer is mixed with an anti-reflection layer to form the mixed layer 305, an anti-glare layer is formed on the surface of the mixed layer 305. On the contrary, if the black dye layer is mixed with an anti-glare layer to form the mixed layer 305, an anti-reflection layer is formed on the surface of the mixed layer 305.
Subsequently, a second optical layer 307, such as an anti-reflection layer anti-glare layer, is formed on the surface of the mixed layer 305. It notes that the mixed layer 305 and the second optical layer 307 can reduce the interference with the light from outside, and further improve the light transparency and contrast ratio. Moreover, the second optical film 307 also needs to have the proper characteristics with transparency, hardness, adhesion, thermal endurance and durability. Besides, if the second optical film 307 is an anti-glare layer, utilizing an appropriate method, such as sandblasting, embossing or blending a plurality of transparent particles to form a surface of asperity on the second optical layer 307 to achieve the effect of anti-glaring. Finally, the polarizer of the present invention is accomplished.
Still another preferred embodiment of this invention will be explained with reference to the drawings of
Due to the fact that the plurality of dichroism materials within the polymer film 401/401′ such as Iodine ion is still emitting the specific wavelength under the dark statement after applying the voltage, therefore; the statement of light leakage in the dark is generated within the LCD apparatus. However, the contrast ratio of the LCD apparatus is definite as light brightness divided by dark brightness so that the problem of light leakage in the dark will influence the dark brightness and the value of the ratio, and further influence the view angle of the LCD apparatus. In order to solve the problem as above mentioned, the present invention provides at least a mixed layer 405/405′ formed on one of the protective films 403/403′. The mixed layer 405/405′ comprises a black dye layer and a first optical layer and a resin (not shown in the figure) that absorbs the light emitted from the dichroism materials within the polymer films 401/401′. Therefore, the dark brightness of the LCD apparatus is reduced to improve the contrast ratio, and further enhance the view angle of the LCD apparatus. The resin is a thermal resin and the first optical film is an anti-reflection layer or anti-glare layer. In addition, the black dye layer within the mixed layer 405/405′ has the property of saturation for absorbing the light so that the thickness of the mixed layer 405/405′ can be utilized to decide the desirable saturation.
Next, a second optical layer 407/407′, such as an anti-reflection layer anti-glare layer, is formed on the surface of the mixed layer 405/405′. It notes that the mixed layer 405/405′ and the second optical layer 407/407′ can reduce the interference with the light from outside, and further improve the light transparency and contrast ratio. Moreover, the second optical film 407/407′ also needs to have the proper characteristics with transparency, hardness, adhesion, thermal endurance and durability. Besides, if the second optical film 407/407′ is an anti-glare layer, utilizing an appropriate method, such as sandblasting, embossing or blending a plurality of transparent particles to form an surface of asperity on the second optical layer 307 to achieve the effect of anti-glaring.
It notes that the black dye layer and the first optical layer in the mixed layer 405/405′ can be independent, that is; the black dye layer can form on one of the protective films 403/403′ formed on the polymer film 403/403′. The first optical layer is formed on the black dye layer, and then the second optical layer is subsequently formed thereon.
According to the description of preferred embodiments of the present invention, as mentioned above, it will be realized that present invention provides a polarizer comprising a black dye to absorb the wavelength emitted from the dichroism materials in the polymer film. Hence, the value of dark brightness can be reduced, and the contrast ratio can be enhanced. Therefore, the view angle of the display apparatus is improved.
The preferred embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the preferred embodiments can be made without departing from the spirit of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 093107540 | Mar 2004 | TW | national |
