# Evaluating the Quality of Light Emitted by Smartphone Displays
## 2 Materials and Methods  
### The Selected Samples  
This study was conducted on nine different smartphones. The basic technical data of the sample selected are presented in Table 1. Most of the samples were produced by one manufacturer. On the one hand, this determines certain limitations of the presented research. On the other hand, different samples released in different years were examined, which, considering the continuous development of mobile phone display technology, will help observe specific trends over the last few years. Moreover, the nine samples were due to the low availability of older models and the low budget for this study. The chosen samples vary in terms of release date, type of display, specific technical parameters, and price range. The oldest smartphone tested (sample 9) was released in 2014, while the newest was released in 2024 (sample 1). The smartphones under study also feature different displays, mainly Super AMOLED. One sample has a Super AMOLED+, which the manufacturer claims primarily improves color quality and higher brightness (luminance). Two different LCDs (both backlight types) were also tested. LCDs in smartphones are becoming increasingly rare. However, it was tested for wider comparison purposes. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Sample** & **Release Date** & **Model** & **Display Type** & **Size** & **Ratio** & **Length** & **Width** & **PPI** & **Frequency** & **Color** \\ \hline
1 & April 2024 & \
\begin{tabular}{c} Samsung \\ Galaxy M15 \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 6.5\({}^{\prime\prime}\) & 19.5.9 & 2340 & 1080 & 396 & 90 & 24 bit \\ \hline
2 & March 2023 & \
\begin{tabular}{c} Samsung \\ Galaxy A34 \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 6.6\({}^{\prime\prime}\) & 19.5.9 & 2340 & 1080 & 390 & 120 & 24 bit \\ \hline
3 & October 2020 & \
\begin{tabular}{c} Samsung \\ Galaxy S20 FE \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 6.5\({}^{\prime\prime}\) & 20.9 & 2400 & 1080 & 407 & 120 & 24 bit \\ \hline
4 & December 2019 & \
\begin{tabular}{c} Samsung \\ Galaxy A71 \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED+ \\ \end{tabular} & 6.7\({}^{\prime\prime}\) & 20.9 & 2400 & 1080 & 393 & 60 & 24 bit \\ \hline
5 & April 2019 & \
\begin{tabular}{c} Samsung \\ Galaxy A40 \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 5.9\({}^{\prime\prime}\) & 19.5.9 & 2340 & 1080 & 437 & 60 & 24 bit \\ \hline
6 & April 2017 &
\begin{tabular}{c} LG 66 \\ \end{tabular} & IPS LCD & 5.7\({}^{\prime\prime}\) & 18.9 & 2880 & 1440 & 564 & 60 & 24 bit \\ \hline
7 & March 2017 & \
\begin{tabular}{c} Samsung \\ Galaxy S8 \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 5.8\({}^{\prime\prime}\) & 18.5.9 & 2960 & 1440 & 570 & 60 & 24 bit \\ \hline
8 & December 2014 & \
\begin{tabular}{c} Samsung Galaxy A5 \\ AMOLED \\ \end{tabular} &
\begin{tabular}{c} Super \\ AMOLED \\ \end{tabular} & 5.0\({}^{\prime\prime}\) & 16.9 & 1280 & 720 & 294 & No data & 24 bit \\ \hline
9 & February 2014 &
\begin{tabular}{c} Samsung \\ Galaxy Grand Neo \\ \end{tabular} & TFT LCD & 5.0\({}^{\prime\prime}\) & 15.9 & 800 & 480 & 186 & No data & 24 bit \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The specification of selected smartphone samples. All tested smartphone samples are relatively new and do not have manufacturing defects or mechanical damage resulting from a short use time, similar to each sample. On the one hand, this allowed for better stabilization of parameters during the tests; on the other hand, the use times are relatively short, which does not contribute to internal degradation of individual screens. All the collected samples are claimed to support 16.7 million colors, corresponding to a color depth of 24 bits. The sample group includes budget smartphones (samples 1 and 9), mid-range smartphones (samples 2, 3, 4, 5, and 8), and two of the highest models from different manufacturers (samples 6 and 7).