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  1. #11
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    Re: Rangeman - LCD display fading at certain angles

    Quote Originally Posted by Scratchesaddcharacter View Post
    It because the light comes at the display from the rear and the layers it travels through refracts the light through the display, therefore tilting the watch display counters the refracted light and produces a clearer picture. The display is designed to be looked at from the front, the light entering from the layers behind causes a refraction of the light. The tilt corrects the refraction hence viewing at an off centre position makes the display clearer.

    Depending on where the LED is located the light refraction will be different on each model and the angle you hold the watch to gain a sharper clearer display will also be different.

    in simple terms light travels from A to B following a path of least time or the quickest route a straight line. Travelling through an slower medium (through the rear of the LCD to the front) slows and bends the light for it to appear in a different place. Hence the refraction and the fact that you have to tilt to counter it.

    Sound has a similar habit too.

    Snells Law and Fermat's principle apply.

    These displays are passive reflective LCD displays. The LED is only used for backlighting purposes.

    You're right that there are issues with refraction and diffraction at play here, especially with the multiple air/glass interfaces in the stack up. I would imagine refraction being worse at larger viewing angles than from 0 degrees (straight on). Diffraction plays a part in reducing readability at wide viewing angles and even viewing straight on.

    The displays that are used in our beloved G-Shocks are cheap reflective passive TN displays. I think the bigger issue with these displays is that with TN, the highest contrast is not at 0 degrees but at an angle that's off of center. If you look at an iso contrast chart, the area with the highest contrast is a blob something like 10-20 degrees off center in the 6 o'clock direction. That loss of contrast looking straight on might be perceived as loss of sharpness since the digits aren't as dark as at off angles. If I was a Casio engineer, I would design the display to have the highest contrast off center as most people would look at it off center, for quick glances.
    Last edited by kevio; June 22nd, 2017 at 01:11.
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  2. #12
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    Re: Rangeman - LCD display fading at certain angles

    Old thread revived for more questioning, when the answer's already given in the old posts 3 years ago. Here I borrowed the picture from a member on page 1 for illustration purpose (see below). Sorry it's a little hard for a 3D representation with the primitive tool I have. But you can see the Z axis is when you're looking at a perfect right angle to the display of the watch. That is not the optimal viewing angle. It is actually not comfortable to look at the watch at a direct right angle when being worn on the wrist.

    The optimal viewing angle is actually below the Z plane and slightly to the left. It is actually consistent to how a person is looking at his watch naturally, when wearing it on the left wrist. It is believed by many of us in the forum that the Casio engineers purposely chose this focal point, so that it matches the natural anatomical position of how majority of people are looking at their watches. That also explains why when wearing the watch on the right wrist, and looking from the right side of the watch, the display is not as clear.

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    Note that, this is not just for the Rangeman, but also true for many G-Shocks and other Casio watches. Whether this is a specific design element from Casio, obviously I don't know. But from the evidence we see, it's certainly plausible.
    Last edited by Watch_Geekmaster; June 22nd, 2017 at 07:03. Reason: Add note.

  3. #13
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    Re: Rangeman - LCD display fading at certain angles

    Thanks for marking up the picture Geekmaster. That illustrates my point exactly that viewing the display slightly off of direct gives the best contrast. Adjusting the angle of maximum contrast to be off angle was how we designed some of the displays used in early PDAs...if anyone still remembers what that is.
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  5. #14
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    Re: Rangeman - LCD display fading at certain angles

    Quote Originally Posted by kevio View Post
    Thanks for marking up the picture Geekmaster. That illustrates my point exactly that viewing the display slightly off of direct gives the best contrast. Adjusting the angle of maximum contrast to be off angle was how we designed some of the displays used in early PDAs...if anyone still remembers what that is.
    Oh yeah! I still have a Palm or 2, and an HP Pocket PC somewhere in my storage. Pretty much obsolete when smart phones came.

  6. #15
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    Re: Rangeman - LCD display fading at certain angles

    It's evolution that PDAs would die out and the founders of Palm saw that. Some of the Palm stuff have my designs in them. :)
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    Re: Rangeman - LCD display fading at certain angles

    Quote Originally Posted by Watch_Geekmaster View Post
    Oh yeah! I still have a Palm or 2, and an HP Pocket PC somewhere in my storage. Pretty much obsolete when smart phones came.
    I still have my Compaq PDA, it was so good I gave up on it and bought a diary and biro.

  8. #17
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    Re: Rangeman - LCD display fading at certain angles

    The display needn't be so, look at the smart watches available or the Sinn Hydro Quartz (oil filled) watch, the display looks painted on the outside. Casio use old dated tech on the LCD screen that are occasionally incrementally updated. Still, it's better than having to charge a watch every few hours.

  9. #18
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    Re: Rangeman - LCD display fading at certain angles

    Quote Originally Posted by Scratchesaddcharacter View Post
    The display needn't be so, look at the smart watches available or the Sinn Hydro Quartz (oil filled) watch, the display looks painted on the outside. Casio use old dated tech on the LCD screen that are occasionally incrementally updated. Still, it's better than having to charge a watch every few hours.
    You hit the nail on the head. The old dated displays in our watches are very low power and perfect for these 10 year or solar watches. Smart watch displays are all TFT or OLED, which are power hogs. This is in addition to the huge processor and wireless technologies, which are just as power hungry.
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  10. #19
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    Re: Rangeman - LCD display fading at certain angles

    Aa
    Last edited by bmmh05; March 30th, 2018 at 18:40.

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