NEC NP901W - Page 3

NEC Display Solutions of America, Inc.
NP901W Installation Guide
Ceiling Mounted and Desktop Rev 1.0
www.necdisplay.com NP901W Page 3 of 6
Formulas
The Projection Formulas use the image width for calculation. Image height is the same for all aspect ratios, only horizontal image
size varies when using a 16:10 aspect ratio screen. For proper projector placement, determine the image width for a desired screen
size. Use the Screen Formulas below to calculate all screen dimensions. Plug in the image width “W” for a 4:3 aspect ratio image in
the Projection Formulas.
Refer to the diagrams (page 5) and charts below for popular screen sizes 16:9 screens:
Definitions: 16:9 Screen Formulas:
W = Image Width W = H x 16/9
H = Image Height (size) H = W x 9/16
B = Vertical distance between lens center and screen center Screen Diagonal = W x 18.358/16
C = Throw distance
D = Vertical distance between lens center and screen top
(screen bottom for desktop application)
Projection Formulas:
B = 0.273W
C(wide) = 1.448W – 1.823
C(tele) = 1.7399W – 1.820
D = -0.042W
α(wide) = tan¯¹ (B/C(wide))
α(tele) = tan¯¹ (B/C(tele))
Note: Tilting the front of the projector or down by more than 45° from level could reduce lamp life by up to 20%.
Distance Chart for popular 16:10 aspect ratios on a 16:9 screen
Diagonal Width(W) Height (H) Diagonal Width(W) Height (H)
inches inches inches inches inches inches inches
49 43 24 45 38 24 10 54 - 65 10.8 - 9.0
73 64 36 68 58 36 16 82 - 98 10.8 - 9.0
92 80 45 85 72 45 20 102 - 123 10.8 - 9.0
100 87 49 92 78 49 21 112 - 134 10.8 - 9.0
106 92 52 98 83 52 23 119 - 143 10.8 - 9.0
110 96 54 102 86 54 24 123 - 148 10.7 - 9.0
120 105 59 111 94 59 26 134 - 162 10.7 - 9.0
122 107 60 113 96 60 26 137 - 165 10.7 - 8.9
133 116 65 123 104 65 28 149 - 179 10.7 - 8.9
135 117 66 125 106 66 29 151 - 182 10.7 - 8.9
159 139 78 147 125 78 34 179 - 215 10.7 - 8.9
161 140 79 149 126 79 35 181 - 218 10.7 - 8.9
230 201 113 213 181 113 49 260 - 313 10.7 - 8.9
275 240 135 255 216 135 59 311 - 374 10.7 - 8.9
-9
-4
-4
-5
-8
-5
-3
-4
-4
-4
-2
-2
-3
-3
inchesinches inches
C
w ide - tele
D
α
w ide - tele
Screen Size (16:9)
Image Size (16:10)
on a (16:9) screen
B
Note:
For screen sizes not indicated on the projection tables, use the formulas on page above.