The effect of time in use on the display performance of the iPad

Caffery, Liam J., Manthey, Kenneth L. and Sim, Lawrence H. (2016) The effect of time in use on the display performance of the iPad. British Journal of Radiology, 89 1063: 20150657. doi:10.1259/bjr.20150657


Author Caffery, Liam J.
Manthey, Kenneth L.
Sim, Lawrence H.
Title The effect of time in use on the display performance of the iPad
Journal name British Journal of Radiology   Check publisher's open access policy
ISSN 1748-880X
0007-1285
Publication date 2016-05-16
Year available 2016
Sub-type Article (original research)
DOI 10.1259/bjr.20150657
Open Access Status Not yet assessed
Volume 89
Issue 1063
Start page 20150657
Total pages 1
Place of publication London, United Kingdom
Publisher British Institute of Radiology
Language eng
Subject 2741 Radiology Nuclear Medicine and imaging
Abstract Objective: The aim of this study was to evaluate changes to the luminance, luminance uniformity and conformance to the digital imaging and communication in medicine greyscale standard display function (GSDF) as a function of time in use for the iPad. Methods: Luminance measurements of the American Association of Physicists in Medicine (AAPM) Group 18 task group (TG18) luminance uniformity and luminance test patterns (TG18-UNL and TG18-LN8) were performed using a calibrated near-range luminancemeter. Nine sets of measurements were taken, where the time in use of the iPad ranged from 0 to 2500h. Results: The maximum luminance (L) of the display decreased (367-338cdm) as a function of time. The minimum luminance remained constant. The maximum nonuniformity coefficient was 11%. Luminance uniformity decreased slightly as a function of time in use. The conformance of the iPad deviated fromthe GSDF curve at commencement of use. Deviation did not increase as a function of time in use. Conclusion: This study has demonstrated that the iPad display exhibits luminance degradation typical of liquid crystal displays. The L of the iPad fell below the American College of Radiology-AAPM-Society of Imaging Informatics in Medicine recommendations for primary displays (>350 cdm) at approximately 1000h in use. The L recommendation for secondary displays (>250 cdm) was exceeded during the entire study. The maximum non-uniformity coefficient did not exceed the recommendations for either primary or secondary displays. The deviation from the GSDF exceeded the recommendations of the TG18 for use as either a primary or secondary display. Advances in knowledge: The brightness, uniformity and contrast response are reasonably stable over the useful lifetime of the device; however, the device fails to meet the contrast response standard for either a primary or secondary display.
Formatted abstract
Objective:
The aim of this study was to evaluate changes to the luminance, luminance uniformity and conformance to the digital imaging and communication in medicine greyscale standard display function (GSDF) as a function of time in use for the iPad.

Methods:
Luminance measurements of the American Association of Physicists in Medicine (AAPM) Group 18 task group (TG18) luminance uniformity and luminance test patterns (TG18-UNL and TG18-LN8) were performed using a calibrated near-range luminance meter. Nine sets of measurements were taken, where the time in use of the iPad ranged from 0 to 2500 h.

Results:
The maximum luminance (Lmax) of the display decreased (367–338 cdm−2) as a function of time. The minimum luminance remained constant. The maximum non-uniformity coefficient was 11%. Luminance uniformity decreased slightly as a function of time in use. The conformance of the iPad deviated from the GSDF curve at commencement of use. Deviation did not increase as a function of time in use.

Conclusion:
This study has demonstrated that the iPad display exhibits luminance degradation typical of liquid crystal displays. The Lmax of the iPad fell below the American College of Radiology–AAPM–Society of Imaging Informatics in Medicine recommendations for primary displays (>350 cdm−2) at approximately 1000 h in use. The Lmax recommendation for secondary displays (>250 cdm−2) was exceeded during the entire study. The maximum non-uniformity coefficient did not exceed the recommendations for either primary or secondary displays. The deviation from the GSDF exceeded the recommendations of the TG18 for use as either a primary or secondary display.

Advances in knowledge:
The brightness, uniformity and contrast response are reasonably stable over the useful lifetime of the device; however, the device fails to meet the contrast response standard for either a primary or secondary display.
Keyword Radiology, Nuclear Medicine & Medical Imaging
Radiology, Nuclear Medicine & Medical Imaging
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
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Created: Thu, 26 May 2016, 23:55:05 EST by Burke, Eliza on behalf of Centre for On-Line Health