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Anyone found a GOOD 128x64 sunlight readable display?

Discussion in 'Embedded' started by John Harlow, Aug 11, 2004.

  1. John Harlow

    John Harlow Guest

    I have an application which will require a highly readable outdoor display.
    I am using an Optrex F-51553 but it isn't cutting it.

    Has anyone seen a really good LCD / VFD / somethingelse display which works
    REALLY WELL outdoors?
     
    John Harlow, Aug 11, 2004
    #1
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  2. John Harlow

    vax3900 Guest

    Any Non-color LCD display should be readily sun light readable.

    vax, 3900
     
    vax3900, Aug 11, 2004
    #2
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  3. John Harlow

    Rick Merrill Guest

    That's what the Optrex is, but it has a contrast ratio of only 6:1
    and no spec on brightness.

    BTW, what is "viewing angle... 6 o-clock" supposed to mean???
    - http://www.optrex.com/SiteImages/LitCentral/51553.pdf.

    -- RM
     
    Rick Merrill, Aug 11, 2004
    #3
  4. John Harlow

    John Harlow Guest

    That's what the Optrex is, but it has a contrast ratio of only 6:1 and no
    spec on brightness.

    It sure would be nice if everyone just supplied things like brightness on
    their datasheets for all their products, whether good or bad. I hate
    marketing departments.
    I wondered the same thing. Perhaps it means it can only be read at dusk ;)
     
    John Harlow, Aug 11, 2004
    #4
  5. A standard B/W LCD has no brightness from itself. All the brightnes it has,
    comes either from a backlight of from the ambient light. And the more
    ambient light it gets, the higher the contrast.

    Meindert
     
    Meindert Sprang, Aug 11, 2004
    #5
  6. ;)

    It is the angle from which the LCD shows the highest contrast. 6 o'clock
    means that it is best viewed from lower than right in front of it. LCD's
    also have 12 o'clock directions. An LCD watch is typically 6 o'clock while a
    table-top device with an LCD on the front is typcally viewed from a higher
    standpoint and therefore has a 12 o'clock display. If you view an LCD from
    the opposite direction, you will hardly see the segments turn black anymore.
    The faint image that you see is the shadow of the segments on the
    back-reflector.

    Meindert
     
    Meindert Sprang, Aug 11, 2004
    #6
  7. John Harlow

    Rick Merrill Guest

    Fair enough, but the Optrex has a builtin backlight ...
     
    Rick Merrill, Aug 11, 2004
    #7
  8. John Harlow

    Rick Merrill Guest

    Who invented THAT standard?! I have an embedded control panel for
    an operator who may be at different places in front of the machine
    yet still needs to see the screen. For TFT displays the maximum
    viewing angle I have seen is +- 60 degrees or 120° side to side.

    Top to bottom viewing is less important because the operator's
    height doesn't change ;-)
     
    Rick Merrill, Aug 11, 2004
    #8
  9. BTW, what is "viewing angle... 6 o-clock" supposed to mean???
    It means the display has an asymmetric viewing cone, and the view
    angle BELOW dead-on horizontal is bigger than the view angle ABOVE
    dead-on horizontal.
     
    Lewin A.R.W. Edwards, Aug 11, 2004
    #9
  10. Who invented THAT standard?![/QUOTE]

    This is to do with VERTICAL viewing angle.

    It is a fact of life to do with structuring the light to go through the
    polarisers of the TFT itself, it is NOT a standard as such but the limitation
    of TFT technology. However if you make the glass one way round the contrast
    ratio is better when viewed below a line at right angles to the middle of
    the screen, typical application Laptop screens, the other way round is
    used for monitor displays and what has generically in the LCD market been
    called industrial displays.

    If you do not believe this happens look at your screen from above and below
    the display and see the differences.
    Side to side viewing angle is easier to achieve, you will find the VERTICAL
    viewing angle, for operators of different heights, is a much smaller range.
    All your operators are the same height?

    Top to bottom viewing is IMPORTANT and causes colour changes. The amount of
    times I see people trying to do digital photo manipulation on 18bit displays
    and complain that the print out is wrong compared to the screen, when they
    are in fact viewing the screen at the wrong angle.

    I have spent too many years looking at these artefacts and the corrections
    required on live video feeds, to know that in many applications it is
    important in quite a few applications. Flat colour GUI interfaces without
    images see the problem LESS due to the normally limited range of actual
    colours over the WHOLE screen.
     
    Paul Carpenter, Aug 12, 2004
    #10
  11. also have 12 o'clock directions. An LCD watch is typically 6 o'clock while a
    It is easier (=cheaper) to make LCDs that have a "preferred view
    orientation". Symmetric-angle LCDs are either:

    1. Narrow angle, or
    2. More expensive than asymmetric-angle LCDs.

    LCDs with wide viewing angle are only justified in monitor and TV
    applications, and often not even then, for the low-cost monitor market
    at any rate.
    +/-80 degrees all around is commonly available, at least in the larger
    sizes (17" and up). This is usually achieved with a special coating and
    often at the expense of brightness.
    It is *very* important if you are either designing an appliance to work
    in portrait mode, or if your appliance can be either placed on a desk or
    mounted on a wall according to user preference (e.g. industrial
    monitor).
     
    Lewin Edwards, Aug 12, 2004
    #11
  12. Yes. But this backlight does hardly contribute to the illumination of the
    display when outside. This backlight is only necessary to view the display
    in the dark. Try to read something about reflective, transflective and
    transmissive LCD's and it'll become all clear.

    Meindert
     
    Meindert Sprang, Aug 12, 2004
    #12
  13. It is not an invented standard, it is just a physical fact of LCD displays.
    Yes, and mine is even 170 degrees, both horizontal and vertical. But these
    are different displays. such a display depends on special filters and a very
    bright backlight, that's why you don't see anything on them when the
    backlight is off. It's an entirely different technology than the Optrex and
    other reflective displays.
    Ah, and they're all selected on the same length at their job interview?

    Meindert
     
    Meindert Sprang, Aug 12, 2004
    #13
  14. An LCD designed to be read in direct sunlight should not *have* any
    brightness to be specced. You want a reflective display for such
    environment, not a backlighted one --- fighting the sun's incoming
    illumination with a (battery-powered) backlight is a battle you can't
    win in the long run, and it's not worth trying.
     
    Hans-Bernhard Broeker, Aug 12, 2004
    #14
  15. John Harlow

    Rick Merrill Guest

    ....
    [/QUOTE]

    Now that I think of it, this was the best answer!
    Yeah, we know. But why is there no degrees :) What happened to
    4'oclock - happy hour?-)
    Of course; that is all pretty obvious.
    Certainly, but why is there not a range of 12, 1,2,3,4,5,6 o'clock? - RM
     
    Rick Merrill, Aug 12, 2004
    #15
  16. John Harlow

    Rick Merrill Guest

    Lewin Edwards wrote:

    ....
    Thanks for the information.
    Yes of course (c.f. smiley). In our case the operator can adjust the
    vertical angle once then moves from side to side. I suppose in
    other cases the operator might stand or sit making vertical viewing
    angle important. - RM
     
    Rick Merrill, Aug 12, 2004
    #16
  17. On Thursday, in article <MTMSc.240529$a24.97545@attbi_s03>
    LCD makers like to use quasi standards, and hide as much as possible (even
    in the data sheets) that may look bad. For example in various 'standards'
    over time VGA meant 640 x 480 x 16 colour, SVGA meant 640 x 480 x 256+
    colours upwards, then came XGA and other definitions. LCD makers use

    640 x 480 VGA
    800 x 600 SVGA
    1024 x 768 XGA
    1280 x 1024 }
    1600 x 1200 } UXGA

    However their vertical viewing angles are often ranges like -10 to +30
    degrees, or -30 to +10 so rather than give absolute figures they know
    the vertical viewing offset is a known attribute so they actually normally
    only quote the offset direction for simplicity to sales people. For a lot
    of applications like laptops that is sufficient as the angle of the display
    is easily adjustable to compensate. My experience of LCDs is more that
    those selling/making are more interested in hype and quasi standards than
    speccing the parts.

    I have before now had to measure what the viewing angles are with sensors
    in a dark box to get actual angles!
     
    Paul Carpenter, Aug 12, 2004
    #17
  18. John Harlow

    Pete Fenelon Guest

    There's also the new laptop 1400x1050, and I've seen pseudo-"widescreen"
    at various resolutions - 1280x800 being one. Weren't SGI LCDs available
    in a rather blatantly widescreen 1600x900? ;)

    1280x1024 is an odd one really, 5x4 rather than 4x3!

    pete
     
    Pete Fenelon, Aug 12, 2004
    #18
  19. John Harlow

    CBFalconer Guest

    you are all talking about color, and I think the OP wanted BW.
     
    CBFalconer, Aug 13, 2004
    #19
  20. John Harlow

    Rick Merrill Guest

    1- this is a very informative thread!
    2- the OP Had B&W that did not cut it, but he did not explict say he
    Wanted only B&W, as I recall. - RM
     
    Rick Merrill, Aug 13, 2004
    #20
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