NEC Solutions (America), Inc.
Visual Systems Division
LT280 Installation Guide
Ceiling Mounted and Desktop
Rev 1.1
www.necvisualsystems.com
LT280
Page 1 of 6
Contents
Product Description, Lens Specs, Notes and Formulas
Pg 1
Diagrams
&
Distance
Charts
Pg 2
Cabinet
Dimensions_____________ Pg 3
Ceiling
Mount
Dimensions _________ Pg 4
Input
Panel
and
Control
Codes
Pg 5
Product
Description
Type:
3
panel
LCD
projector, Brightness: LT280:
2500
ANSI
Lumens
0.7”
p-Si
TFT
w/MLA
Dimensions:
12.2”(W)
x
10.2”(H)
x
4.4”(D)
Resolution: LT280:
1024
x
768 Weight: 6.17
lbs
Lens
Specifications
Throw Ratio:
1.5 – 1.8:1 (for 100” diagonal) Focal
Length:
21.69mm
–
25.9mm
Offset Angle:
9.5° - 12.1° (for
100”
diagonal)
F/#: 1.7
-
2.0
Screen
Sizes:
25”
-
300”
diagonal
(4:3)
Manual
Focus/Manual
Zoom
Notes
For screen sizes not indicated on the projection tables, use the formulas below.
If the figures on the tables do not match the results of formulas, use the figures in the table.
•
All calculations are based on 4:3 aspect ratio.
•
Distances are in inches, for millimeters multiply by 25.4.
•
Distances may vary
±
5%.
Formulas
The Projection Formulas use the image width for calculation. For proper projection placement, determine the image width
for the desired screen 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
=
0.298W
C
(wide) = 1.481W - 1.425
C
(tele)=1.787 – 1.406
D
= 0.0771W
α
(wide) = tan¯¹ (B/C(wide))
α
(tele) = tan¯¹ (B/C(tele))
