Joined: 02 Jul 2011
|Posted: Sat Jul 02, 2011 10:05 am Post subject: What LEDs to use for an outdoor moving display?
|Hi all. I am new here and this is will be my first post.
I have done a small scrolling display project using led dot matrices. For this display, I used 2.3" indoor matrices with luminous intensity of 12 mcd for each matrix. I want to make an outdoor version of this. My problem is that I could not find any 2.3" led matrix that could provide enough brightness for outdoor environment. So I decided to make my own matrices. Initially, I used my available water clear bright LEDs (red and green) for the matrix. The LEDs were bright enough (actually TOO bright for me) for outdoor when viewed directly, but loses a lot of its brightness when viewed side ways. I believe that this problem was due to the LEDs having narrow viewing angle. I also read somewhere that the lens makeup being water clear also had something to do with it. Diffusing it could probable improve the viewing angle but that would require a lot of work (I think). So I want to ask the experts here: what type of LED could you suggest for such application? What luminous intensity should the LEDs have if they are diffused type? I was also wondering if the cylindrical LEDs could be used for such project. I am looking at cylindrical leds with flat/cove tops having high viewing angle (100-150) and high luminous intensity. Have anyone worked with cylindrical type LEDS? Would they be suitable for moving displays? I am currently choosing among the following LEDs:
(1) luminous intensity: 85 mcd, color: super red, lens: diffused, viewing angle: 40 degrees, round
(2) luminous intensity: 60 mcd, color: green, lens: diffused, viewing angle: 40 degrees, round
(3) luminous intensity: 200 mcd, color: super red, lens: water clear, viewing angle: 80 degrees, cylindrical
(4) luminous intensity: 100 mcd, color: green, lens: water clear, viewing angle: 80 degrees, cylindrical
(5) luminous intensity: 80 mcd, color: super red, lens: water clear, viewing angle: 150 degrees, cylindrical
(6) luminous intensity: 30 mcd, color: super red, lens: water clear, viewing angle: 150 degrees, cylindrical
The luminous intensity of the above LEDs may seem low compared to other outdoor LEDs but their datasheets says that these LEDs are suitable for outdoor environment. Any suggestions? I would really really appreciate any help. Thanks!