OT: Vibrating LCD display
 

Hey everybody. I have a project upon me to figure out how to isolate vibrations of an LCD screen mounted in a Mobile Home. The screen is bolted to a wooden support in the fiberglass part of the cab (above and behind the driver). Now, that's not real important...I was just wondering if anybody here had suggestions as to how I can reduce the vibrations of the screen. The vibrations are so bad on rough pavement that the display cannot be read. Maybe somebody knows of a good dampening material for automotive applications, and where I can get it. It's just like a DVD screen that somebody here might have in their car. So, if you have any suggestions, let me know.
mat-1

Koni Struts

surely there is some sort of spring type deal that you could use, rather than bolting straight to the wood mount?

Foam rubber glued between two boards or a pillow or a seat cushion. So vibration really shakes up the LCD screen? I would think that would be a lot better than a CRT screen. Any idea why it is distorted by the vibration? DVD and small TV are finding there way into vechicles, could be a serious problem.

A couple of web sites
 

These may offer something of interest.

www.tpcdayton.com
www.qontrol.com

School project Mat?
 

School or Government job (you know, By the people, FOR the people;) )

Those links looked interesting for a stock product for a single app, but knowing the division you are working for this is probably a school project. Let me know. I worked for a TPE (thermoplastic elastomer) company working with new applications. I can probably point you in the direction of some people who an help you out.

Todd

Actually, it's for work and for school, since I have to work as part of my schooling (as you know). So, the sites aredub sent are actually the two places my boss pointed me to, but they don't give enough info to give me anything better than a guess at which will work. I was hoping somebody had some experience or definite knowledge of some sort of foam or something that will reduce the vibrations. I dunno, I'll probably just have to guess anyway. But, if you have info, hook me up.
Mat-1

Hi Mat,
Springs is just springs, dampers is just dampers but rubber is a spring and a damper.

Your system can be reduced to a mass, spring and damper system.

The way to get results without a lot of time is to get different stiffness (density) of say foam rubber or just use different thickness of the stuff and glue it between two plywood sheets say 1/4 inch thick. Make up a few and see which works better.

Want to measure the spring rate? Hang some weight from the board and measure the deflection. Plot a line of weight verses the deflection. The slope is the spring rate.

No easy way to measure the damping coeficients as they is a function of velocity. Unless you drop a known weight and calculate accell due to fall. Never tried that but it might work.

If you have access to a real time analizer with accelerometer you can find excitation frequencies. You could also calculate the natural frequency of the mass spring system Fn=(k/m)^.5

Also in case you ever wonder, when the Fn of a spring mass, tire strut system = the excitation frequency of the tire on rumble strips, the strut blows out!

If you have time, can you tell me why the LCD has a poor display when it shakes? I thought it was sort of solid state.

Thanks
 

Thanks for that technical bit of info. I should be able to use lots of the stuff I've been given. To correct an earlier mistake, svxter gave me the same links as my boss, not aredub. Thanks for those. The LCD has a poor display (from what i've been told, I don't get to see the prob till tomorrow) because the screen moves so much you can't read it. Gotta go, I'll write more later.
Mat-1

Additional thought
 

Your LCD may go up and down 2 or 3 inches over a rough road (for example the road past the tunnels in the Jemez) in reference to the observer. Your observer's butt/seat cushion accomodations and springs and also should be taken into consideration. An ideal combination would match the observer's displacement with the LCD's displacement to make no distortion. Good luck finding something that can match that!

Stand immediately in front of the LCD on rough roads there should be little difference in displacement and less distortion.

If you want to know how to isolate an LCD at 3000Hz with .001" displacement, I know some guys at work that can do that.

Mat
 

I took a look around my former employers website and it focuses on material types not applications or designs. It would probably be best if you contacted one of their applications engineers to discuss your application further. They should be able to help you with a design.

www.aestpe.com

Good luck!

When are you coming back to the land of ice and snow?