NEC Display Solutions of America, Inc.
V311X/V311W Installation Guide
Ceiling Mounted and Desktop
Rev 1.0
www.necdisplay.com
V311X/V311W
Page 2 of 8
Formulas
The Projection Formulas use the image width for calculation. For proper projection placement, determine the image width
for the desired scree
n size. Use the Screen Formulas below to calculate all screen dimensions. Plug in the width for “W” in
the Projection Formulas.
Refer to the diagrams and charts for popular screen sizes on page 2:
Definitions:
4:3 Screen Formulas:
W = Image Width
W = H x 4/3
H = Image Height (size)
H = W x 3/4
B = Vertical distance between lens center and screen center
Screen Diagonal = W x 5/4
C = Throw distance
D = Vertical distance between lens center and screen top
(screen bottom for desktop application)
Projection Formulas:
B
= 0.487W
C
(wide) = 1.94W
C
(tele)
= 2.165W
D
= 0.112W
α
(wide) =
tanˉ¹ (B/C(wide))
α
(tele) = tanˉ¹ (B/C(tele))
Distance Chart for popular 4:3 screens
Note:
For screen sizes not indicated on the
projection tables, use the formulas on page 1.
Diagonal Width(W) Height (H)
inches
inches
inches
inches
30
24
18
12
46
-
52
14.1
-
12.7
60
48
36
23
93
-
104
14.1
-
12.7
67
53.6
40.2
26
104
-
116
14.1
-
12.7
72
57.6
43.2
28
111
-
125
14.1
-
12.7
84
67.2
50.4
33
130
-
146
14.1
-
12.7
90
72
54
35
139
-
156
14.1
-
12.7
100
80
60
39
155
-
173
14.1
-
12.7
120
96
72
47
186
-
208
14.1
-
12.7
150
120
90
58
232
-
260
14.1
-
12.7
180
144
108
70
279
-
312
14.1
-
12.7
210
168
126
82
325
-
364
14.1
-
12.7
240
192
144
94
372
-
416
14.1
-
12.7
270
216
162
105
418
-
468
14.1
-
12.7
300
240
180
117
465
-
520
14.1
-
12.7
19
22
24
27
9
11
13
16
6
6
8
8
D
α
w ide - tele
degrees
Screen Size (4:3)
5
inches
3
B
C
w ide - tele
inches
