Abstract:
A projection screen includes first and second basic materials, at least one diffusing layer sandwiched between the first and the second basic materials, a writing layer coating the second basic material, and a reflecting layer over the first basic material; the writing layer allows the ink of whiteboard markers to adhere on and get erased therefore the projection screen allows people to write thereon with whiteboard markers besides being used for images to be projected on by a projector.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the invention  
         [0002]     The present invention relates to a projection screen, more particularly one, which allows the ink of whiteboard markers to adhere on and get erased, thus allowing people to write thereon with whiteboard markers besides being used for images to be projected on.  
         [0003]     2. Brief Description of the Prior Art  
         [0004]     Projectors are usually used to project figures, charts etc on screens to show information in a meeting or lecture, thus helping the audience to understand. There are two major ways to project images, front projection and rear projection; a projector is placed in front of a screen in front projection while a projector is placed behind a screen in rear projection.  
         [0005]     However, no matter which projecting way is used, the projection screen doesn&#39;t allow people to write or make marks thereon with markers. Consequently, the user either has to take the trouble to prepare and use a whiteboard and markers in a lecture or add the extra information and words to the contents of the projector films previously before printing the contents on projector films. Neither of the above two ways is convenient.  
       SUMMARY OF THE INVENTION  
       [0006]     It is a main object of the invention to provide an improvement on a projection screen to overcome the above-mentioned inconvenience. The projection screen of the present invention includes first and second basic materials, at least one diffusing layer sandwiched between the first and the second basic materials, and a writing layer coating the second basic material. The writing layer allows the ink of whiteboard markers to adhere on and easily get erased therefore the projection screen allows people to write thereon with whiteboard markers besides being used for images to be projected on. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will be better understood by referring to the accompanying drawings, wherein:  
         [0008]      FIG. 1  is a view of the first preferred embodiment of a projection screen in the present invention, and  
         [0009]      FIG. 2  is a view of the second preferred embodiment.  
         [0010]      FIG. 3  is a view of the third preferred embodiment,  
         [0011]      FIG. 4  is a view of the fourth preferred embodiment  
         [0012]      FIG. 5  is a view of the fifth preferred embodiment  
         [0013]      FIG. 6  is a view of the sixth preferred embodiment.  
         [0014]      FIG. 7  is a view of the seventh preferred embodiment,  
         [0015]      FIG. 8  is a view of the eighth preferred embodiment  
         [0016]      FIG. 9  is a view of the ninth preferred embodiment  
         [0017]      FIG. 10  is a view of the tenth preferred embodiment.  
         [0018]      FIG. 11  is a view of the eleventh preferred embodiment, and  
         [0019]      FIG. 12  is a view of the twelfth preferred embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     Referring to  FIG. 1 , a first preferred embodiment of a projection screen  1 , which is provided for use in front projection, includes a polymer plastic basic material  11 , at least two diffusing layers  12  over an upper side of the polymer plastic basic material  11 , another polymer plastic basic material  13  over an upper side of an uppermost one of the diffusing layers  12 , a writing layer  14  coating an upper side of the polymer plastic basic material  13 , and a reflecting layer  15  over a lower side of the polymer plastic basic material  11 ; there are two diffusing layers  12  in the first preferred embodiment shown in  FIG. 1 .  
         [0021]     Referring to  FIG. 2 , a second preferred embodiment of a projection screen  1  for use in front projection includes a polymer plastic basic material  11 , at least two diffusing layers  12  over an upper side of the polymer plastic basic material  11 , another polymer plastic basic material  13  over an upper side of an uppermost one of the diffusing layers  12 , a writing layer  14  coating an upper side of the polymer plastic basic material  13 , a reflecting layer  15  over a lower side of the polymer plastic basic material  11 , a black adhesive layer  16  over a lower side of the reflecting layer  15 , and a detaching film  17  stuck to a lower side of the black adhesive layer  16 ; there are two diffusing layers  12  in the second preferred embodiment shown in  FIG. 2 . Images projected on the projection screen will be more distinct because of the color of the black adhesive layer  16 . Further, the projection screen can be fixed on an object, on which images are to be projected, by means of sticking the black adhesive layer  16  to the object after the detaching film  17  is removed.  
         [0022]     The polymer plastic basic materials  11  and  13  can be PET (Polyethylene Terephthalate), PP (Polypropylene), PEN, PE (polyethylene), PA (nylon), PMMA (acryl) or PC (Polycarbonate).  
         [0023]     The ingredients of the diffusing layers  12  can include powdery polymer diffusing particulates (e.g. acryl, melamine, and silicone particulates) with diameters between 1 μ and 30 μ, titanium dioxide, and viscid liquid resin, which are mixed together. Or alternatively, the diffusing layer  12  can be made of only one kind of material chosen from a group including titanium dioxide, polymer diffusing acryl particulates, melamine, and silicone. The diffusing layer  12  also can be made of two or three kinds of materials chosen from a group including titanium dioxide, polymer diffusing acryl particulates, melamine, and silicone.  
         [0024]     Ingredients of the chemical coating material of the writing layer  14  can include wear-resistant UV-curable melamine resin, of which the proportion to the coating material of the writing layer  14  is between 95% and 99%, and photoinitiator, of which the proportion to the coating material of the writing layer  14  is between 1% and 5%; when UV-curable melamine resin and photoinitiator are mixed, condensation will occur, and in turn the surface tension on the writing layer  14  will be in such a range as to allow the ink of whiteboard markers to adhere on and easily get erased from the projection screen.  
         [0025]     Instead, ingredients of the chemical coating material of the writing layer  14  can include UV-curable polyurethane resin, of which the proportion to the whole coating material is between 95 and 99%, and photoinitiator, of which the proportion to the coating material is between 1% and 5%.  
         [0026]     And instead, ingredients of the chemical coating material of the writing layer  14  can include UV-curable acrylic resin, of which the proportion to the whole coating material is between 95% and 99%, and photoinitiator, of which the proportion to the coating material is between 1% and 5%. And instead, ingredients of the chemical coating material of the writing layer  14  can include melamine, of which the proportion to the whole coating material is between 10% and 50%, polyurethane, of which the proportion to the whole coating material is between 5% and 25%, UV-curable acrylic copolymer resin, of which the proportion to the coating material is between 10% and 50%, and photoinitiator, of which the proportion to the whole coating material is between 1% and 5%.  
         [0027]     Further, ingredients of the chemical coating material of the writing layer  14  can include melamine, of which the proportion to the whole coating material is between 70% and 90%, UV-curable polyurethane resin, of which the proportion to the whole coating material is between 5% and 25%, and photoinitiator, of which the proportion to the whole coating material is between 1% and 5% instead.  
         [0028]     And, ingredients of the chemical coating material of the writing layer  14  can include polyurethane, of which the proportion to the whole coating material is between 5% and 25%, UV-curable acrylic copolymer resin, of which the proportion to the coating material is between 70% and 90%, and photoinitiator, of which the proportion to the whole coating material is between 1% and 5%.  
         [0029]     The reflecting layer  15  can be made of aluminum or silver. And, the material of the adhesive layer  16  can be acryl, rubber or silicone.  
         [0030]     Referring to  FIG. 3 , a third preferred embodiment of a projection screen  1  for use in front projection includes a polymer plastic basic material  21 , at least one diffusing layers  22  over an upper side of the polymer plastic basic material  21 , another polymer plastic basic material  23  over an upper side of an uppermost one of the diffusing layers  22 , a writing layer  24  coating an upper side of the polymer plastic basic material  23 , a reflecting layer  25  over a lower side of the polymer plastic basic material  21 , and a blackening layer  26  over a lower side of the reflecting layer  25 .  
         [0031]     Referring to  FIG. 3 , a third preferred embodiment of a projection screen  2  for use in front projection includes a polymer plastic basic material  21 , at least one diffusing layers  22  over an upper side of the polymer plastic basic material  21 , another polymer plastic basic material  23  over an upper side of an uppermost one of the diffusing layers  22 , a writing layer  24  coating an upper side of the polymer plastic basic material  23 , a reflecting layer  25  over a lower side of the polymer plastic basic material  21 , and a blackening layer  26  over a lower side of the reflecting layer  25 .  
         [0032]     Referring to  FIG. 4 , a fourth preferred embodiment of a projection screen  3  for use in front projection includes a polymer plastic basic material  31 , a reflecting layer  32  over an upper side of the polymer plastic basic material  31 , at least one diffusing layers  33  over an upper side of the reflecting layer  32 , another polymer plastic basic material  34  over an upper side of an uppermost one of the diffusing layers  33 , a writing layer  35  coating an upper side of the polymer plastic basic material  34 , and a blackening layer  36  over a lower side of the polymer plastic basic material  31 ; there are two diffusing layers  33  on the fourth preferred embodiment shown in  FIG. 4 .  
         [0033]     Referring to  FIG. 5 , a fifth preferred embodiment of a projection screen  4  for use in front projection includes a polymer plastic basic material  41 , a diffusing layer  42  over an upper side of the polymer plastic basic material  41 , another polymer plastic basic material  43  over an upper side of the diffusing layer  42 , another diffusing layer  44  over an upper side of the polymer plastic basic material  43 , a writing layer  45  coating an upper side of the diffusing layer  44 , a reflecting layer  46  over a lower side of the polymer plastic basic material  41 , and a blackening layer  47  over a lower side of the reflecting layer  46 .  
         [0034]     Referring to  FIG. 6 , a sixth preferred embodiment of a projection screen  5  for use in front projection includes a polymer plastic basic material  51 , a reflecting layer  52  over an upper side of the polymer plastic basic material  51 , a diffusing layer  53  over an upper side of the reflecting layer  52 , another polymer plastic basic material  54  over an upper side of the diffusing layer  53 , another diffusing layer  55  over an upper side of the polymer plastic basic material  54 , a writing layer  56  coating an upper side of the diffusing layer  55 , and a blackening layer  57  over a lower side of the polymer plastic basic material  51 .  
         [0035]     Referring to  FIG. 7 , a seventh preferred embodiment of a projection screen  6  for use in front projection includes a polymer plastic basic material  61 , a reflecting layer  62  over an upper side of the polymer plastic basic material  61 , at least one diffusing layers  63  over an upper side of the reflecting layer  62 , another polymer plastic basic material  64  over an upper side of an uppermost one of the diffusing layers  63 , a writing layer  65  coating an upper side of the polymer plastic basic material  64 , a black adhesive layer  66  over a lower side of the polymer plastic basic material  61 , and a detaching film  67  stuck to a lower side of the black adhesive layer  66 ; the projection screen  6  can be stuck on an object by means of the black adhesive layer  66  after the detaching film  67  is removed; there are two diffusing layers  63  in the seventh preferred embodiment shown in  FIG. 7 .  
         [0036]     Referring to  FIG. 8 , a eighth preferred embodiment of a projection screen  7  for use in front projection includes a polymer plastic basic material  71 , a diffusing layer  72  over an upper side of the polymer plastic basic material  71 , a second polymer plastic basic material  73  over an upper side of the diffusing layer  22 , a second diffusing layer  74  over an upper side of the second polymer plastic basic material  73 , a writing layer  75  coating an upper side of the second diffusing layer  74 , a reflecting layer  76  over a lower side of the polymer plastic basic material  71 , a black adhesive layer  77  over a lower side of the reflecting layer  76 , and a detaching film  78  over a lower side of the black adhesive layer  77 ; thus, the projection screen  7  can be stuck on an object after the detaching film  78  is removed.  
         [0037]     Referring to  FIG. 9 , a ninth preferred embodiment of a projection screen  8  for use in front projection includes a polymer plastic basic material  81 , a reflecting layer  82  over an upper side of the polymer plastic basic material  81 , a diffusing layer  83  over an upper side of the reflecting layer  82 , a second polymer plastic basic material  84  over an upper side of the diffusing layer  83 , a second diffusing layer  85  over an upper side of the second polymer plastic basic material  84 , a writing layer  86  coating an upper side of the second diffusing layer  85 , a black adhesive layer  87  over a lower side of the polymer plastic basic material  81 , and a detaching film  88  over a lower side of the black adhesive layer  87 ; thus, the projection screen  8  can be stuck on an object after the detaching film  88  is removed.  
         [0038]     The following preferred embodiments of a projection screen of the present invention are provided for use in rear projection:  
         [0039]     Referring to  FIG. 10 , a tenth preferred embodiment of a projection screen  9  includes a polymer plastic basic material  91 , at least one diffusing layers  92  over an upper side of the polymer plastic basic material  91 , a writing layer  93  coating an upper side of an uppermost one of the diffusing layers  92 , a transparent adhesive layer  94  over a lower side of the polymer plastic basic material  91 , and a detaching film  95  over a lower side of the transparent adhesive layer  94 ; thus, the projection screen  9  can be stuck on an object after the detaching film  95  has been removed; there is single diffusing layer  93  in the present preferred embodiment shown in  FIG. 10 .  
         [0040]     Referring to  FIG. 11 , a eleventh preferred embodiment of a projection screen  10  includes a polymer plastic basic material  101 , a writing layer  102  over an upper side of the polymer plastic basic material  101 , at least one diffusing layers  103  over a lower side of the polymer plastic basic material  101 , a transparent adhesive layer  104  coating a lower side of a lowermost one of the diffusing layers  103 , and a detaching film  105  over a lower side of the transparent adhesive layer  104 ; thus, the projection screen  10  can be stuck on an object after the detaching film  105  is removed; there is single diffusing layer  103  in the present preferred embodiment shown in  FIG. 11 .  
         [0041]     Referring to  FIG. 12 , a twelfth preferred embodiment of a projection screen  20  includes a polymer plastic basic material  201 , a writing layer  202  over an upper side of the polymer plastic basic material  201 , at least one adhesive diffusing layers  203  over a lower side of the polymer plastic basic material  201 , and a detaching film  204  over a lower side of a lowermost one of the diffusing layers  203 ; thus, the projection screen  20  can be stuck on an object after the detaching film  204  is removed; there is single diffusing layer  203  in the present preferred embodiment shown in  FIG. 12 .  
         [0042]     The polymer plastic basic materials  21 ,  23 ,  31 ,  34 ,  41 ,  43 ,  51 ,  54 ,  61 ,  64 ,  71 ,  73 ,  81 ,  84 ,  91 ,  101 , and  201  of the last ten preferred embodiments can be PET (Polyethylene Terephthalate), PP (Polypropylene), PEN, PE (polyethylene), PA (nylon), PMMA (acryl) or PC (Polycarbonate).  
         [0043]     The writing layers  24 ,  35 ,  45 ,  66 ,  65 ,  75 ,  86 ,  93 ,  102 , and  202  have polymer diffusing particulates added therein, which can be PMMA (acryl), PU or silicone particulates, and of which the diameters are between 0.1 μ and 20 μ; furthermore, the proportion of the polymer diffusing particulates to the writing layers is between 2% and 30%.  
         [0044]     Materials of the reflecting layers  25 ,  32 ,  46 ,  52 ,  62 , 76 , and  82  can be aluminum or silver. And, materials of the black adhesive layers  16 ,  66 ,  77 , and  87  and materials of the transparent adhesive layers  94  and  104  can be acryl, rubber or silicone.