Abstract:
An anti-glare device mounted around one or more light sources in the shade of a lamp is provided. The device comprises a substrate formed of transparent plastic, and two optical layers formed on inner and outer surfaces of the substrate respectively. The device can substantially eliminate reflections and glare and thus provide a sufficient while subtle lighting to a reading area.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to anti-glare devices and more particularly to an anti-glare device mounted between lamps and shade of a light (e.g., table lamp) for providing an optimum lighting.  
         [0003]     2. Description of Related Art  
         [0004]     It is frequently that a computer user may focus his/her eyes on the screen for a long period of time. This can cause eye fatigue. Further, glare may occur on the screen from overhead lights and windows. These factors can deteriorate eyesight. For the annoying, undesired glare, it can be classified as contrast glare, direct glare, or reflective glare (i.e., reflection). The latter two factors can be reduced to a minimum if a light (e.g., table lamp) is well designed. Reflections are frequently occurred when an angle of incident light is equal to a reflecting angle thereof.  
         [0005]     Sunglasses are able to protect the eyes from the sun&#39;s glare by employing the principles of polarizer. However, a person wearing a pair of sunglasses may see a darker view because about half of light (i.e., parallel light) is eliminated. As such, the principles of polarizer cannot be employed in the improvement of lamps.  
         [0006]     Recently, there is a type of lamp shade in the form of diffusive, reflective filter. It is advantageous for substantially eliminating reflections but it cannot eliminate direct glare. Moreover, it can undesirably reduce luminance. Hence, a need for improvement exists.  
       SUMMARY OF THE INVENTION  
       [0007]     It is an object of the present invention to provide an anti-glare lamp shade so as to substantially eliminate reflections and glare and thus providing a sufficient while subtle lighting to a reading area.  
         [0008]     To achieve the above and other objects, the present invention provides an anti-glare device mounted around one or more light sources in a shade of a lamp, comprising a substrate formed of transparent plastic; and two optical layers formed on inner and outer surfaces of the substrate respectively.  
         [0009]     The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a preferred embodiment of anti-glare device according to the invention;  
         [0011]      FIG. 2  is a sectional view of the device in  FIG. 1 ;  
         [0012]      FIG. 2A  is a detailed view of the area in circle  2 A in  FIG. 2 ;  
         [0013]      FIG. 3  is a perspective view of the device mounted between lamps and shade of a table lamp;  
         [0014]      FIG. 4  is an exploded view of the upper portion of the table lamp in  FIG. 3 ;  
         [0015]      FIG. 5  is a side plan view of the upper portion of the table lamp in  FIG. 3 ; and  
         [0016]      FIG. 6  is a side plan view illustrating the paths of rays of light when the lamp in  FIG. 3  is turned on. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     Referring to FIGS.  1  to  2 A, there is shown an anti-glare device  1  constructed in accordance with the invention. The device  1  is formed in the shape of a thin parallelepiped container having an open top. The device  1  comprises a substrate  10  and two optical layers  20  formed on inner and outer surfaces of the substrate  10 . The substrate  10  is formed of heat-resistant, transparent plastic and has an operating temperature about 180° C. The plastic can be PET (polyethylene telephthalate), PC (polycarbonate), teflon, or acrylic. The optical layer  20  is coated, sprayed, UV (ultraviolet) impinged, or printed on the substrate  10 . For the printing, it can be embossed printing, intaglio process, or stencil printing. The formed device  1  is thus able to eliminate glare and reflections.  
         [0018]     Referring to FIGS.  3  to  6 , the device  1  is adapted to mount between lamps  30  (i.e., light source) and shade of a light (e.g., hanging pendant, ceiling lamp, corner lighting, or table lamp  2  in the embodiment). Rays of light emitted from the lamps  30  passes through the device  1  prior to reaching the object to be lit. Fortunately, the device  1  can cause the reduction of luminance and brightness to a minimum. In detail, as shown in  FIG. 6  specifically, most rays of light emitted from the lamps  30  impinge on a plurality of small areas  40  on the inner optical layer  20 . The areas  40  function as convex lenses for spreading rays of light. As such, subtle rays of light pass the substrate  10  to reach a plurality of small areas  40  on the outer optical layer  20  while glare is reflected. Again, the areas  40  function as convex lenses for spreading rays of light. As a result, a reading area  50  is evenly lit by rays of light with increased while stable luminance and brightness.  
         [0019]     Following is an experiment conducted in a dark room with respect to a table lamp incorporated the anti-glare device  1  (the invention) and a typical table lamp (prior art). In detail, each of the table lamps is placed on a sheet of paper (e.g., A3). The lamps  30  of the table lamp are adjusted to be parallel with the sheet of paper. Relative to a base point by a predetermined distance, a plurality of test points are set in a plurality of rows and columns wherein each point is spaced apart from an adjacent point of the same row or column by 5 cm as illustrated below.  
                                           (1)                                                    
 
         [0020]     Following is a table showing data of luminance measured on the sheet of paper with respect to the invention and prior art after turning on the invention and prior art respectively. The luminance is expressed in the unit of LUX.  
                                                                                 (3)            The   1   1142   2   1198   3   1128   4   938   5   691       invention       Prior art   1   1277   2   1304   3   1169   4   1074   5   936       The   6   1542   7   1613   8   1493   9   1288   10   955       invention       Prior art   6   1527   7   1511   8   1372   9   1220   10   1035       The   11   1940   12   1850   13   1760   14   1496   15   1160       invention       Prior art   11   1716   12   1726   13   1661   14   1395   15   1176       The   16   2100   17   2070   18   1910   19   1661   20   1324       invention       Prior art   16   1835   17   1820   18   1691   19   1456   20   1195       The   21   2120   22   2130   23   1920   24   1730   25   1352       invention       Prior art   21   1717   22   1723   23   1608   24   1408   25   1194       The   26   2000   27   2000   28   1985   29   1717   30   1280       invention       Prior art   26   1798   27   1740   28   1618   29   1425   30   1219       The   31   1901   32   1901   33   1786   34   1511   35   1206       invention       Prior art   31   1609   32   1651   33   1520   34   1344   35   1160       The   36   1641   37   1585   38   1509   39   1310   40   1051       invention       Prior art   36   1461   37   1410   38   1326   39   1211   40   1028       The   41   1220   42   1225   43   1170   44   993   45   844       invention       Prior art   41   1218   42   1165   43   1072   44   1020   45   916                  
 
         [0021]     Following is another table showing data of average luminance by sampling luminance data on different measured points of the sheet of paper with respect to the invention and prior art respectively. The luminance is also expressed in the unit of LUX.  
                                                                   (2)                distance                    shade   5 cm   10 cm   20 cm                       The invention   1975   1958   1624           Prior art   1714   1696   1467                      
 
         [0022]     In view of the above experiment, it is found that the anti-glare device  1  of the invention can not only increase luminance and brightness but also significantly reduce glare and reflections.  
         [0023]     While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.