Patent Publication Number: US-2011063244-A1

Title: Optical film and display module using the same

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an optical film and a display module using the optical film. 
     2. Description of Related Art 
     A commonly used display module with a display panel may further include a touch panel formed on the display panel to replace traditional input devices, such as control buttons, mice, keyboards, etc. to facilitate users&#39; input by contact. 
     Touch panels can be resistance, capacitance, electronic-magnetic, exterior sound wave, infrared ray, and other types. Capacitance touch panels provide multi-touch function, durability, and long lifespan, therefore, they are popularly used. 
     Display modules, whether in the form of cathode ray tube, flat panel, or touch panel, require a plurality of optical films to be deployed for protecting the display panel, improving the image quality, and improving viewability. Referring to  FIG. 3 , a clear optical adhesive  100  includes an adhesive layer  102  and two release layers  104 ,  106 . The adhesive layer  102  adheres to the panels or films. The release layers  104 ,  106  are formed on opposite sides of the adhesive layer  102  to protect the clear optical adhesive  100  from attracting impurities before use. 
     Referring to  FIG. 4 , an anti-reflection film  200  includes a base layer  202 , a tri-acetyl cellulose (TAC) layer  204  formed on the base layer  202 , the adhesive layer  102 , and the release layer  104 / 106  formed on the adhesive layer  102 . The TAC layer  204  resists glare and reflection. Typically, the thickness of the base layer  202  is about 0.005 mm, of the adhesive layer  102  is about 0.025˜0.175 mm, and of the TAC layer  204  is about 0.08 mm, resulting in a total thickness of the anti-reflection film  200  of about 0.11˜0.26 mm. The anti-reflection film  200  is frequently used in the display module to reduce reflections between the panels, such that the image quality of the display module is improved. 
     Also referring to  FIG. 5 , a capacitance display module  300  includes a thin displaying layer  310  having a liquid crystal display (LCD) panel, a plurality of adhesive layers  102 , an anti-reflection film  200 , a capacitance touch panel  320 , and a protective film  330 . The anti-reflection film  200  is adhered to one side of the capacitance touch panel  320  which is facing the LCD panel  310  through the adhesive layer  102  by removing the release layer  104 / 106  of the anti-reflection film  200 . The base layer  202  of the anti-reflection film  200  is adhered to the LCD panel  310  by one of the adhesive layers  102  of the anti-reflection film  200 . The protective film  330  is adhered to the other side of the capacitance touch panel  320  away from the LCD panel  310  through one of the adhesive layers  102  of the clear optical adhesive  100 . In this capacitance display module  300 , various layers, such as the adhesive layers  102 , the anti-reflection layer  200 , and the protective film  330  are added to adhere, resist reflection, or protect the capacitance display module  300 , with at least two or three layers between the LCD panel  310  and the capacitance touch panel  320  being added. The total thickness of the layers between the LCD panel  310  and the capacitance touch panel  320  is not less than 0.29 mm. The thickness of the capacitance display module  300  is increased, and time required for adhesion is increased, as manpower and equipment requirements, and rate of quality defect is increased. Furthermore, the capacitance display module  300  having a larger thickness may decrease the permeation of light. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, and all the views are schematic. 
         FIG. 1  is a cross-section of one embodiment of an optical film. 
         FIG. 2  is a cross-section showing a display module using the optical film of  FIG. 1 . 
         FIG. 3  is a cross-section of a typical clear optical adhesive including an adhesive layer and two release layers. 
         FIG. 4  is a cross-section of a commonly used anti-reflection film. 
         FIG. 5  is a cross-section of a commonly used capacitance display module including the anti-reflection film, the adhesive layer, and the release layer. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , one embodiment of an optical film  400  includes a hard coating layer  410 , an anti-glare layer  420 , a first adhesive layer  430 , a second adhesive layer  440 , a first release layer  450 , and a second release layer  460 . The anti-glare layer  420  is adhered on a first side of the hard coating layer  410 , and the second adhesive layer  440  is adhered on a second side of the hard coating layer  410  opposite to the first side. The first adhesive layer  430  is adhered on one side of the anti-glare layer  420  away from the hard coating layer  410 , and the first release layer  450  is formed on one side of the first adhesive layer  430  away from the anti-glare layer  420 . The second release layer  460  is formed on one side of the second adhesive layer  440  away from the hard coating layer  410 . 
     The hard coating layer  410  has a first surface  412  and a second surface  414  opposite to the first surface  412 . The anti-glare layer  420  is adhered on the first surface  412 , and the second adhesive layer  440  is adhered on the second surface  414 . The hard coating layer  410  may be polyester resin such as polyethylene terephthalate (PET), or polyacrylate resin such as polymethyl methacrylate (PMMA) or polycarbonate (PC) and other, or combinations thereof. In the illustrated embodiment, the hard coating layer  410  is PET of 0.03˜0.05 mm thick. The hard coating layer  410  is a base layer of the optical film  400 . The hard coating layer  410  is PET so as to be able to provide superior hardness, durability, stability, fatigue resistance, and good light transmittance. The hard coating layer  410  may be of other materials with favorable hardness and transparency. 
     The anti-glare layer  420  is TAC (tri-acetyl cellulose) of thickness less than or equal to 0.08 mm. In the illustrated embodiment, the thickness of the anti-glare layer  420  is 0.08 mm. 
     The first and second adhesive layers  430 ,  440  are made of optical adhesive with a good light transmittance and a high cohesive force such as acrylic resin. A thickness of each of the first adhesive layer  430  and the second adhesive layer  440  is 0.04˜0.05 mm. In the illustrated embodiment, the thickness of each of the first adhesive layer  430  and the second adhesive layer  440  is 0.05 mm. Alternatively, the first adhesive layer  430  and the second adhesive layer  440  may have different thicknesses. 
     The first and second release layers  450 ,  460  prevent the optical film  400  from attracting impurities before use. In the illustrated embodiment, a total thickness of the optical film  400  is 0.19˜0.23 mm. 
     Also referring to  FIG. 2 , a display module  500  includes a display panel  510  such as a LCD panel, a capacitance touch panel  520 , an optical adhesive  530 , and the optical film  400 . The capacitance touch panel  520  is a double-sided indium tin oxide board, and is adhered to the display panel  510  by the optical adhesive  530 . The optical film  400  is adhered to one side of the capacitance touch panel  520  away from the display panel  510  by removing the second release layer  460  of the optical film  400  and adhering the second adhesive layer  440  of the optical film  400  to the capacitance touch panel  520 . 
     Since the hard coating layer  410  provides durability, stability, fatigue resistance, and transparency, no protective film for the display module  500  is required. Accordingly, the required thickness of the display module  500  is decreased. In addition, the hard coating layer  410  acts both as a base layer of the anti-glare layer  420  and a protective film, such that the display panel  510  is protected from physical damage and the quality of light transmittance of the display module  500  is improved. Since the optical film  400  includes the first adhesive layer  430  and the second adhesive layer  440  on opposite sides, the optical film  400  is thereby easily adhered to other films or panels. In the display module  500 , since lesser adhesive layers are used, adhering time and manpower requirements are decreased, and the adhesion process is simplified. Furthermore, the product yield rate is increased. 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the embodiments or sacrificing all of their material advantages.