Optical, Generating grayscales – Planar ICEBrite EL Display EL552.256-Q2 User Manual

Page 11

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EL552.256-Q2 Operations Manual (OM410-00)

9

Optical

Table 5. Optical Specifications

Luminance

L

on

(areal), min

L

on

(areal), typ

L

off

(pixel), max

34.5 cd/m²
50 cd/m²
0.2 cd/m²

screen center, 120 Hz frame rate
screen center, 120 Hz frame rate
5 points: center plus four corners measured
1.0

±

0.025" from adjacent display edges, 120 Hz

Non-uniformity

All pixels fully lit

26%

Maximum difference two of five points, using
the formula:
LNU%=[1- (min_lum/max_lum)] x 100

Luminance Variation (Temperature)

Maximum

±

15%

Across operating temperature range

Luminance Variation (Time)

Maximum

<10%

15,000 hours at 25

°

C ambient

Viewing Angle

Minimum

>160

°

Contrast Ratio

Minimum
Typical

20:1
40:1

@ 500 lux ambient, 120 Hz frame rate

Generating Grayscales

Some applications may benefit by using grayscales. The Q2 has a maximum
frame rate frequency of 120 Hz. Using the higher frame rate, combined with
flat panel controllers designed for this faster display, it is possible to generate
usable grays through frame rate control and dithering. Video controllers from
manufacturers such as C&T, SMOS, and Cirrus Logic use these methods with
proprietary algorithms to generate grayscales.

The response time of electroluminescent displays is much faster than LCDs,
therefore not all possible grayscales generated by the video controller are
actually usable. Many of the grayscales may flicker or swim. Careful testing is
necessary to select appropriate grayscales for an application, especially when the
electroluminescent displays are driven at less than their maximum frame rate.

For additional information, refer to Planar Application Note 119, Generating
Grayscales
, or contact Planar’s Application Engineering.

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