Abstract:
Curved lenses configured to decode three dimensional content and method of fabricating the same. The lenses comprise a polyvinylalcohol polarizer film laminated with triacetate on both sides, wherein the polarizer film has a polarizing efficiency equal to or exceeding 99% and a transmittance percentage equal to or exceeding 35% and a retarder film (e.g., norbornene copolymer resin) laminated on a front surface of the polyvinylalcohol polarizer film laminated with triacetate and aligned to produce a desired circular polarization responsive to specified retardation wavelengths.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/019,545 filed Jan. 7, 2008. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The embodiments of the present invention relate to lenses designed to decode three dimensional content displayed on television, movie, computer or similar screens or monitors. 
       BACKGROUND 
       [0003]    Three dimensional movies for theatres have been around for decades. With technological advances, three dimensional content is being developed for television, computer monitors and home projectors. In the past, and even today, special glasses allow users to view three dimensional content. Flat paper eyeglasses using red and green film for lenses are the primary glasses being used today. However, flat paper eyeglasses are not very effective for facilitating the desired three dimension effect. In addition, the flat paper eyeglasses are not comfortable and are generally viewed as a novelty. Other flat lenses suffer from the same drawbacks. 
         [0004]    One advancement has been the development of linear and circular polarization for decoding three dimensional content. Despite the advancement, the lens and eyeglass technology has not advanced significantly. 
         [0005]    Thus, there is a need for lenses that take advantage of the linear and circular polarization technologies while more effectively creating the desired three dimensional effect. Advantageously, the lenses and eyeglasses should provide improved optics and contrast while providing user comfort and versatility. It is also beneficial if the lenses may be mounted into stylish frames. 
       SUMMARY 
       [0006]    Accordingly, one embodiment of the present invention is a curved lens configured to decode three dimensional content comprising: a polyvinylalcohol polarizer film laminated with triacetate on both sides, said polarizer film having a polarizing efficiency equal to or exceeding 99% and a transmittance percentage equal to or exceeding 35%; and a retarder film placed over a front surface of the polyvinylalcohol polarizer film laminated with triacetate and aligned to produce a desired circular polarization responsive to specified retardation wavelengths. 
         [0007]    Another embodiment of the present invention is a method of fabricating a curved lens configured to decode three dimensional content comprising: cutting lens blanks from sheets of material comprising: polyvinylalcohol polarizer film laminated with triacetate on both surfaces and a retarder film laminated on a front surface thereof creating a circular polarized film; laminating a layer of triacetate to the retarder film to reach a desired lens thickness; heating the blanks to a deformation temperature; curving the blanks using vacuum suction and/or pressure; cooling the curved blanks; and applying a hard coat on one or both sides of the curved blanks. 
         [0008]    In one embodiment, the retarder is a norbornene copolymer resin such as an Arton film (manufactured by JSR Corp.) or Zenor film (manufactured by Zeon corp.). Conventional adhesives are used to bond the layers forming the lens. In one embodiment, a hard coating is applied to the front and back surfaces of the lens to allow for normal cleaning and extended life. In one embodiment, a lens thickness is between 750 and 1500 microns. 
         [0009]    Other variations, embodiments and features of the present invention will become evident from the following detailed description, drawings and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIGS. 1 and 2  illustrate an exemplary specification sheet for a first lens embodiment of the present invention; 
           [0011]      FIGS. 3 and 4  illustrate an exemplary specification sheet for a second lens embodiment of the present invention; and 
           [0012]      FIG. 5  illustrates a flow chart detailing one embodiment of manufacturing the lenses according to the embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    For the purposes of promoting an understanding of the principles in accordance with the embodiments of the present invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive feature illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention claimed. 
         [0014]    Traditionally flat lenses and frames have been used in 3D glasses. One problem with the flat 3D glasses is that the lenses are distanced from the user&#39;s face and more particularly the user&#39;s eyes. Thus, light is able to enter the user&#39;s eyes from the top, bottom and side of the lenses reducing the visual acuity and contrast thereby reducing the effectiveness of the 3D experience. This is especially true at home or other locations outside of dark movie theatres. Moreover, the current one-size-fits-all approach to flat 3D eyeglasses reduces the quality of the 3D experience and in many cases results in an uncomfortable fit for most users. Accordingly, the embodiments of the present invention seek to overcome the disadvantages of the prior art flat 3D eyeglasses by creating 3D lenses and eyeglasses which are more akin to normal curved lenses and eyeglasses. Consequently, the lenses described herein are generally thicker than traditional flat 3D lenses and curved to prevent ambient light from interfering with the 3D experience. Conventional flat 3D paper lenses are 0.3 to 0.4 mm thick while the embodiments of the present invention are substantially in a range of 0.75 to 1.5 mm. The curvature further enables a better fit on the user&#39;s head. In addition, the thicker lenses enable them to be mounted into stylish frames to which people are more accustomed. 
         [0015]      FIGS. 1-4  show specifications associated with lenses made utilizing the embodiments of the present invention.  FIGS. 1 and 2  depict charts  100  and  105  listing lens specifications according to a first embodiment. The charts  100  and  105  depict dimensions, including width  110  and length  115 , polarization angle  120 , retardation angle  125 , transmittance percentage  130 , polarizing efficiency  135 , thickness  140  and retardation  145 . As shown in charts  100  and  105 , the width ranges from 495 mm to 505 mm; length from 700 mm to 710 mm; polarization angle from −1.0 degree to 1.0 degree; retardation angle from 44.0 degrees to 46.0 degrees (or 134 degrees to 136 degrees); transmittance percentage from 37.5% to 42.5% v; polarizing efficiency of 99% or greater; thickness of 1020 microns to 1080 microns (or 1.02 mm to 1.08 mm) and retardation of 110 to 130 nm. Larger ranges are possible for each of the aforementioned categories. Charts  101  and  106  shown in  FIGS. 3 and 4 , respectively, depict similar lens specifications according to a second embodiment. 
         [0016]    Fabrication of the lenses is accomplished using lamination and thermoforming techniques.  FIG. 5  shows a flow chart  200  detailing one method of fabricating lenses according to the embodiments of the present invention. At  205 , lens blanks are cut from sheets of material comprising: polyvinylalcohol polarizer film laminated with triacetate on both surfaces (i.e., linear polarized film) and a retarder film laminated on a front surface thereof creating a circular polarized film. At  210 , to reach a desired thickness (e.g., 0.9 mm), a layer of triacetate is laminated to the retarder film. A laminator machine forms the sheets of materials such that the axis of the polarizing film and retarder film are aligned properly to small tolerances. In one embodiment, the retarder is an Arton film (manufactured by JSR Corp.) or Zenor (manufactured by Zeon corp.). Polycarbonate materials may also be used as the retarder. Adhesives bind the materials together. The size of the blanks is dictated by the intended frame size. A typical size is 50 mm×70 mm. At  215 , the blanks are placed into a thermoforming machine which heats the blanks to a deformation temperature (e.g., 90° C. to 130° C.). At  220 , the heated blanks are curved to an optically correct curved surface utilizing vacuum suction and/or pressure. The higher the intended base curve (e.g., 4, 6 and 8), the higher the necessary thermoforming temperature. Once formed, at  225 , the curved blanks are cooled and removed from the machine. At  230 , the blanks, now lenses, can be finished with conventional lens dry cutting machines. At  235 , a hard coating is applied over the curved lenses. The hard coating allows normal cleaning and extended use while protecting the operational materials forming the lenses. At  240 , a protective, removable sheets are applied to protect the lenses during subsequent operations including installation into frames, packaging and shipping. 
         [0017]    The triacetate comprises multiple layers itself and has qualities, including transparency, stress-free, birefringence, lightweight and strength. Moreover, the triacetate is responsive to lamination and thermoforming processes and techniques. 
         [0018]    For the circular polarized lenses utilized in the embodiments of the present invention the polyvinylalcohol polarizer film is tinted with iodine crystals to increase polarizing efficiency and transmission to acceptable levels (e.g., &gt;99% and &gt;35%, respectively). 
         [0019]    The curved lenses disclosed herein have numerous advantages over the flat 3D glasses of the prior art. The curved lenses provide a clearer and natural vision of 3D images with greater acuity and contrast. More particularly, the curved lenses reduce light entering the user&#39;s eyes from the side, top or bottom of the eyeglass frames thereby increasing the comfort and contrast associated with the viewed 3D images. The curved lenses can be fitted into any commercial eyeglass frames to create as stylish pair of eyeglasses. 
         [0020]    Although the invention has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.