Product manufacturers have a huge responsibility of making a renewal request for the RoHS Exemptions that do not contain expiry date, as those exemptions will expire on 21 July 2016 and subsequently fall under the RoHS non-compliant category. Manufacturers who have to use the RoHS2 exempted substances to produce their end product even after the expiration date, hence need to make a renewal request. As the exemptions are moving on an expiration track it is to be noted that the European Commission has already received some renewal requests. The received renewal requests are to modify the description for the below mentioned exemptions:
Exemption 13(a): “Lead in white glasses used for optical applications”
Exemption 13(b): “Cadmium and Lead in filter glasses and glasses used for reflectance standards”
Why Optical Device Manufacturers send a renewal request?
Most of the electronic devices use optical and magnetic properties for their functionality along with electrical properties. As per experts in the industry, the requested exemptions for renewal request concern 13(a) & 13(b). Since these exemptions deal with optical systems, devices like laser, optical fibers (which is used for communication and sensing), reflectors and transmitters, optical lenses, surgical and research instruments, manufacturers of these components need to be especially aware of the repercussion of the exemption getting expired.
If the exemption expires some of the specific functions of optical systems could get compromised and EU would then classify the end product as RoHS non-compliant. The following are some of the specific functionalities of optical systems that need manufacturer’s special attention.
- Color balancing:
The use of Lead and Cadmium in the optical systems affects the wavelength and color correction of the images in different ways. Lead and Cadmium elements are used within the glass matrix in form of lead oxide in optical glass and lead oxides, cadmium oxides, cadmium sulphides and cadmium selenides in filter glass. It is necessary to use a combination of chemical substances to improvise image quality rather that cover a broad spectral range. Suppose the color correction is not performed well, there is a chance to get different color effects from the viewpoint of optics:
- Different lateral magnifications will cause to obtain different color effects in the image
- Axial differences will cause only one color for a sharp image usually green is made good but the red and green images are blurred and badly resolved
- Transmission in UV spectral region:
Transmission is strongly reduced in Lead free optical glasses, this ranges from 410 nm to 365 nm and no transmission occurs below 365nm. This functionalities positively impacts the application of electronic transmission devices and hence is a very important attribute.