2. Table of Contents
Product Description.
Technical Aspects.
LCD Memory Effect.
Humidity and Temperature.
Cooling Fan Defect.
Lamp Durability.
3. Product Description
Video projector
Receives a video signal from TV-receiver, PC, BluRay-
Player, gaming console etc.
Projects the pictures on a projection screen.
Uses a lens system.
5. Technical Aspects
Light output
measured in lumens.
from 1500 lm for small rooms with low ambient light up
to over 4000 lm for big screens and/or no lighting
control.
Resolution
common resolutions are 800x600, 1024x768,
1280x720 and 1920x1080 pixels.
other formats have to be scaled.
6. Technical Aspects
Picture deformation
when projector has a horizontal or vertical offset to the
projection screen.
digital or analog correction.
Temperature and noise
heat is produced by the lamp.
fans are needed to protect from
overheating.
7. What could be tested?
LCD Memory Effect.
Button durability.
Remote control (distance, obstacles).
Lamp durability (3000-6000h; On/Off).
Humidity and temperature differences.
Defect of cooling fan.
Light output (decreasing over lifespan).
8. What is to be tested?
LCD Memory Effect: places on the lense can get
darker if they are exposed to bright pictures.
Lamp durability: lamp is designed for 5000
operating hours.
Humidity and Temperature: the projector should be
resistant to inside as well as outside conditions.
Defect of cooling fan: overheating of critical
components should be prevented.
9. LCD Memory Effect Test
To give an idea of different test parameters, I
would like to show a presentation on different
parameters and then show our test.
11. LCD Memory Effect
Results
Check image quality of a pure black respectively pure
white image after each time period.
Protocol at which time and place/color
the effect occured.
13. Lamp Durability
Lamp should endure 5000 hours of usage
(>200 days).
Long time usage and many Power-On/Off
procedures have a bad influence on durability.
To shorten the test time the projector is switched
On/Off frequently.
Randomized On/Off-signals or fixed values.
14. Humidity and Temperature
Intended temperature range for use
between -5° C and +40° C
Intended humidity range for use
between 20 and 90 %
Protocol sheet with intervals
shorter intervals at critical temp. or humidity levels
Test environment
climate chamber
15. Humidity and Temperature
Humidity [%] Temperature [°C] Status
20 20 OK
40 20 OK
60 20 OK
70 20 OK
75 20 …
80 20 …
85 20 …
90 20 …
92 20 …
94 20 …
16. Cooling Fan Defect
System must shut down before overheating
Temperature sensors in the projector case
17. Cooling Fan Defect
1st task: find the critical temperature.
2nd task: configure the built-in temperature sensor.
3rd task: test if the system shuts down when the
critical temperature is reached.