## 3 Results and Discussion
### Patents Landscape  
The seven patent records retrieved by the search strategy are shown in Table 1.  
To address the first research question, these patents were analyzed to answer frequent concerns and uncover patterns in assignees, filings per year, the International Patent Classification (IPC), and benefits. Q1: How are patents in industrial virtual-reality-based usability testing and design review characterized? In terms of assignees, their identification may help the discovery of industry leaders, the evaluation of possible rivals, and the identification of niche players. The widely fragmented dispersion of patent applications across many assignees is intriguing: just one assignee, CCB Fintech and China Construction Bank, submitted two patents, whilst the other patents were filed by different assignees. Figure 1: Systematic review flow diagram, adapted from PRISMA 2020 [21]. Rather than a relatively equal-sized, but large, portfolio held by a few companies, which indicates an active competitive market with strong investments by multiple companies, suggesting that the market is difficult to enter, we discovered a large number of assignees, each with a small number of records, demonstrating a developing technology space. This domain may be entered by acquisition or rapid development. There are several companies, each with a small number of patents, indicating an opportunity to enter this area while it is still young, either by licensing existing technology, purchasing one of the players, or developing new technology that is not already patented. It is also worth noting that three of the six assignees are major financial institutions, while one university filed one of the seven patents. In terms of patent filings per year, Figure 2 illustrates the yearly filing of patents from 2016 to 2020. We omitted 2021 patents from the analysis since they were still being filed at the time of this study. \begin{table}
\begin{tabular}{c c c c} \hline
**Ref.** & **Publication Number** & **Title** & **Assignee** \\ \hline
[31] & CN111414083A &
\begin{tabular}{c} Method and device for availability \\ test of space \\ \end{tabular} & CCB Fintech; China \\ \hline
[32] & CN111414084A &
\begin{tabular}{c} Space availability test laboratory and \\ using the method and device thereof \\ \end{tabular} & Construction Bank \\ \hline
[33] & JP2021068278A &
\begin{tabular}{c} A design-review system and the \\ design-review method \\ \end{tabular} & Nippon Steel Texeng \\ \hline
[34] & US20210011593A1 &
\begin{tabular}{c} System for rendering applications \\ based on real-time accessibility \\ assessment \\ \end{tabular} & Bank Of America \\ \hline
[35] & US20210090343A1 & \
\begin{tabular}{c} A method and a system for design \\ reviews and trainings \\ \end{tabular} &
\begin{tabular}{c} Activa Innovations \\ Software \\ \end{tabular} \\ \hline
[36] & US20190227626A1 &
\begin{tabular}{c} Neuro-adaptive body sensing for \\ user states framework \\ \end{tabular} & HRL Lab LLC \\ \hline
[37] & KR20190088710A &
\begin{tabular}{c} Method for evaluating usability on \\ vehicle infotainment systems \\ \end{tabular} & Hanyang University \\ \hline \end{tabular}
\end{table} 
Table 1: List of retrieved patents. Figure 2: Patent filings per year. We observed an initial period spanning the years 2016 and 2017, with no patents registered. This trend changed in 2018, followed by growth in 2019 and 2020. These results support the claim in [28] that the year 2016 marked a technological breakthrough in the domain of virtual reality. Before 2016, commercial virtual reality systems required users to connect a headset, controllers, and sensors to an external high-end computer, which was an expensive, bulky, and inconvenient setup. Thus, the current all-in-one virtual reality systems are a significant step forward from only a few years ago [38]. The upward trend slowed in 2020, although one likely explanation is the 18 month patent legal secrecy restriction.