4.1
NVIS Response Curves
There are two NVIS response curves. The Class A curve uses a 625 nm minus blue filter which does not allow any red cockpit lighting. The Class B curve uses a 665 nm minus blue filter which allows the use of properly designed NVIS red lighting. Figure 4.1.0-A shows the Class A and Class B relative response curves as compared to the photopic relative response curve.
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Figure 4.1.0-A Photopic, Class A NVIS and Class B NVIS Relative Response |
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Spectral Radiance, Type I Class A Colors
Figure 4.1.0-B shows the normalized spectral radiance curves for the Type I Class A colors of NVIS Blue, NVIS Green A, NVIS Green B, NVIS White and NVIS Yellow Class A. Also shown are the relative photopic response and the relative spectral response of the Class A NVIS. These are the only colors that are allowed in a Class A cockpit.
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Figure 4.1.0-B Normalized Spectral Radiance for Type I Class A NVIS Colors |
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Spectral Radiance, Type I Class B Colors
Figure 4.1.0-C shows the normalized spectral radiance curves for the Type I Class B colors of NVIS Yellow Class B and NVIS Red, the relative photopic response and the spectral response of the Class B NVIS. The NVIS Red is allowed in a Class B cockpit in addition to NVIS Blue, NVIS Green A, NVIS Green B, NVIS White and NVIS Yellow Class B.
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Figure 4.1.0-C Normalized Spectral Radiance for Type I Class B NVIS Colors |
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NVIS Dimming Compatible Dimming
The Type S NVIS Blue, NVIS Green A, NVIS Green B, NVIS White and NVIS Yellow colors can be dimmed to 0.1 footlamberts as required by MIL-L 85762A and MIL-STD 411F for NVIS compatible military aircrew stations. The average display luminance is 0.05 to 0.3 footlamberts at 6.55 VDC for the 28 VDC LED circuits as measured at 23° C.
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Figure 4.1.0-D Typical NVIS Compatible Dimming Range at 23°C (Type S) |
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Minimum Luminance Current
The 28 VDC LED displays require approximately 1 milliamp of current per quadrant before producing a perceptible level of luminance so the LEDs will not light inadvertently due to microamp currents.
Emergency Power Operation
The Type S displays are easily readable in emergency power conditions of 18 VDC producing in excess of 50 footlamberts at 18 VDC.