The article also mentions that disc drives with a thickness of just 8.5mm or 7mm face technological barriers and would have an exponentially higher production cost.
Although slim-type ODDs are unlikely to be given up for use in notebooks, the proportion of notebooks equipped with slim-type ODDs has declined from over 90% to about 80% in 2012 and is likely to drop further to 60-70% in 1-2 years, the sources indicated.
Development of slim-type ODDs with thicknesses of 8.5mm or 7mm for example face technological barriers in optical pick-up heads. In addition, R&D and production costs would be as much as 3-4 times those for 9.5mm models, the sources said.