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VISIBLE LEGEND DISPLAYS:
Visible Legend: VIVISUN 20/20 visible legend displays are Type N per MILPRF- 22885, paragraph 1.2.6 and have visible legends with illuminating characters on an opaque background.
Always Visible White: The legends are reflective white so as to be visible in any light ambient condition except darkened conditions.
Lumination Levels: In darkened conditions the lamps can be energized to produce a legend illumination of 1.0 to 3.0 foot-lamberts.
Color of Illumination: The color of the illuminated visible white legends are either red or blue-white per SAE AS7788, or NVIS green B per MIL-L-85762A.
ADDITIONAL VISUAL FEATURES:
Low Level Uniformity: The displays are uniformly dimmable and at low intensity levels, they maintain their brightness uniformity (have no hot spots).
Viewing Angle: 150° peripherally in direct sunlight and 30° in glare-producing conditions.
Lettering Style: All sunlight readable legends are Globe Condensed caps and all visible white legends are Futura Medium Condensed. Exception: 0.072” characters are Alternate Gothic Condensed.
Character Size: Legends are available with character heights of 0.156”, 0.125”, 0.109” and 0.072”.
SUNLIGHT READABLE LEGENDS:
Legend Readability: The legends when energized at rated voltage are readable in direct sunlight (10,000 foot-candles), including any glare-producing angle up to 15° to the normal of the display viewing surface. When the lamps are not energized, the legends are not discernible and cannot be read in direct sunlight (10,000 foot-candles).
Background Color: The legend viewing area background is a diffuse, matte finish black. It eliminates undesirable glare reflections and minimizes direct sunlight reflections. This enhances the viewability of the legends in direct sunlight.
Luminance Contrast: The average luminance contrast ratio for any lighted legend to background is 0.6 minimum (0.4 minimum for blue) in direct sunlight (10,000 foot-candles) at all glare-producing angles up to and including 15° to the normal of the display viewing surface.
Test Method: Measurement of the luminance contrast is achieved by using the specular reflectance test method per MIL-PRF-22885, paragraph 4.7.36. Values of the luminance contrast ratios for each color at glare angles of 15° are shown in Figure 11.
Figure 11
Color Contrast: In addition to luminance contrast, color contrast is an important factor in sunlight readability. The most readable color is red, then green, yellow, blue and white, which has the least color contrast.
Index of Discrimination: To take into account color contrast as well as luminance contrast, a value called the Index of Discrimination (ID) is determined. The value must exceed 1.0 for the display legends to be considered sunlight readable. The value of the Index of Discrimination for each color at a glare angle of 15° are shown in Figure 11.
Minimum Brightness and Typical Color Coordinates:
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Chromaticity |
Brightness in |
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Color |
x |
y |
Foot-lamberts |
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Red |
0.690 |
0.310 |
150 |
|
Green |
0.360 |
0.605 |
200 |
|
Yellow |
0.585 |
0.410 |
300 |
|
Blue |
0.280 |
0.405 |
150 |
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White |
0.430 |
0.400 |
250 |
| NVIS green B |
See Figure 8 |
200 |
| NVIS yelloq |
See Figure 8 |
200 |
x and y chromaticities are in 1931 CIE Diagram coordinates. For color limit boundaries see Figure 12.
Figure 8
Figure 12
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