What Is the Current Development Status of Wearable Device in Industrial 4.0? Using Technology Acceptance Model to Explore the Willingness and Pattern of Usage of the Consumers

Table 1

Worldwide wearable devices end-user spending by type, 2018–2021 (millions of dollars).

Device type	2018	2019	2020	2021
Smartwatch	12,412	17,047	22,803	27,388
Head-mounted display	5,354	7,183	10,609	15,501
Ear-worn	6,780	7,885	8,716	9,927
Sports watch	3,647	4,121	4,555	4,912
Wristband	3,405	3,194	3,115	3,055
Smart clothing	848	1,151	1,746	2,202
Total	32,446	40,581	51,545	62,985

Source: Gartner [5].