Macron International Group Ltd.
Macron International Group Ltd.
Reiteration of our RoHS-Compliant Photoresistor
Request for Refusing Exemptions in the Annex to the RoHS Directive 2002/95/EC
Macron International Group Ltd., devoted to the manufacture of high-quality and compliant electrical and electronic substances, would like to reiterate that we have the ability to manufacture environmental-friendly and RoHS-compliant CdS Photoresistor / Photocell. The ingredient level of cadmium (Cd) and five other restricted substances in each unit of homogeneous material produced by us not only meets the requirements set forth in the European Commission’s RoHS Directive 2002/95/EC, but also is even lower than the limit. Therefore, we believe there is an urgent need to let the EC and the public know that it is possible to manufacture RoHS-compliant photoresistors. Subsequently, we would like to request the EC to turn down the exemption requests made by manufacturers who are incapable and reluctant to produce up-to-standard photoresistors.
Claims and Justifications
First of all, we claim that our photoresistors comply with RoHS specifications. In March 2006, we wrote to the EC to announce that the cadmium concentration in our products is below 100ppm, which is the limit stated in the RoHS Directive 2002/95/EC. We could prove that our photoresistors are RoHS-compliant with the certificate of the SGS Lab, see attachment 1, SGS Photocell report 1,2, which carried out a test for us around a year ago. However, as there are growing discussions and arguments over the definition of homogeneous materials, we have recently requested the RoHS and WEEE Test Technology Lab of the City University of Hong Kong directed by Professor Y.C. Chan to carry out another test on our photoresistors, focusing on the ingredient level of the 6 elements (cadmium, lead, mercury, chromium VI, polybrominated biphenyls and polybrominated diphenyl ethers) that fall under the RoHS requirements. While SGS broke down the photoresistor into two homogenous materials for test, RoHS and WEEE Test Technology Lab sticks more closely to the RoHS homogenous material definition and “mechanically disjoints” the photoresistor into three homogeneous materials, see attachment 2, RoHS and WEEE Macron Photocell. Obviously, this recent test is more thoughtful and profound, supplementing and adding more credibility to the preceding test. As indicated in the attached Test Report, see attachment 2, RoHS and WEEE Macron Photocell, the cadmium ingredient level contained in the homogeneous material of our photoresistor is only 52ppm, which is far less than the RoHS restricted concentration value. It is a concrete evident that photoresistors produced by MACRON are RoHS-compliant.
Secondly, we claim consideration from the EC to turn down applications for exemption to RoHS Directive 2002/95/EC, which came into force since July 2006. We would like to point out that a number of manufacturers are actually not putting efforts in finding ways to correct and improve their products so as to meet the RoHS specifications. In other words, they did not attempt or are not trying hard enough to reduce the cadmium concentration level in photoresistors to comply with the RoHS requirements. There is no solid evidence that they undertake to make their products RoHS-compliant. What they have been doing is to file for exemptions and their requests are totally ungrounded. Therefore, they do not deserve to be exempted, and our concrete evidence clearly proves that it does a way to lower the photoresistor’s Cadmium level under RoHS requirements.
Thirdly, we claim that our photoresistors are also environmental friendly. Since the level of hazardous substances in our newly developed photoresistors are reduced to such a low value ( 52ppm of cadmium ), the use of Macron’s photoresistors in optoelectronic components such as optocoupler would be beneficial to the environment either. For environmental sake and for the great effort that we have made, we sincerely ask the EC to actualize and execute the RoHS Directive and allow for no exemptions.
What is a CdS Photoresistor / Photocell?
Photoresistor / Photocell is one type of photoelectric semiconductor component. The electrical resistance of a photoresistor changes as incident light falling on it varies in intensity. Such a characteristic of photoresistors renders the function of circuit control in electrical circuits.
Among the many kinds of photosensitive materials, CdS (Cadmium Sulphide) exhibits the best photosensitivity. Thus CdS is widely employed by all manufacturers as a major raw material in the manufacturing of photoresistor / photocell.
Difference between the Environmental-friendly Photoresistor and the Existing Photoresistor
l Appearance / Size:
Our environmental-friendly photocell is in no way different in appearance or size from the photocells currently in supply in the market.
l Specification / Resistance Range:
The specifications applicable to the existing photocell are also applicable to our environmental-friendly photocell. They are exactly the same. Besides, the market resistance range found in the existing photocell can be totally covered by our environmental-friendly photocell.
l Base Material:
There is no difference between the base material of our RoHS-compliant photocell and that of the incompliant photocell existing in the market. Both of them are made by ceramic.
l Production Line and Hardware:
The production line and the hardware adopted in the manufacturing of our RoHS-compliant photocell are exactly the same as those adopted to produce the incompliant photocell. In other words, we can use the current production line to manufacture environment-friendly photocell without investing to set up a new line.
Advantages of Using Macron’s RoHS-compliant Photocell
l Appearance / Size:
The end user does not have to modify or change their present hardware, hence saving both time and money in the following ways:
1. No extra training to labour.
2. No extra expenses on modifying or changing the software in the production process.
3. No electrical circuit change to existing products.
4. No extra molds for production.
5. Low component count (sensor housing must be as small as possible).
l Specification / Resistance Range:
Compared with the use of silicon-based sensors (photodiode), the end user does not have to add any amplifier or change the circuit in his or her products. Again, money and time can be totally saved as:
1. No adjustment necessary.
2. No extra expenses on modifying, changing or adding software to the products.
3. Environmental-friendly photocell can totally replace any broken photocell in old circuits. Existing photocells can be substituted step by step.
l Base Material:
Since our environmental-friendly photocell is made of ceramic like the existing photocells, money and time can be saved in the following ways:
1. No need to purchase a brand new material to make RoHS-compliant photocell.
2. Base material kept in stock (i.e. ceramic) can be used for the new production (manufacturing of RoHS-compliant photocell).
l Production Line and Hardware:
Like the base material, the production line currently engaged in the production of existing photocell can be used to manufacture the environmental-friendly photocell. Money and Time will be totally saved as:
1. No extra captital to be invested in new hardware and machines.
2. No extra production area.
3. No extra labour needed.
4. Manufacturer can simply use the existing production line to manufacture something new and better.
Application circuits
Since our environmental-friendly and RoHS-compliant photocell can easily and totally replace the existing incompliant photocells, the basic application circuit for our environmental-friendly photocell will be exactly the same as that of the existing photocells.
Macron International Group Ltd.
Room 703, Kowloon Building, 555 Nathan Road, Hong Kong.
Tel: 852 2781 3743 Fax: 852 2613 9222
Web Site: www.macron.com.hk e-mail:
Macron International Group Ltd.
Figure 1: The basic application circuit for RoHS-compliant photocell
Figure 2: The basic application circuit for the existing incompliant photocell
Macron International Group Ltd.
Room 703, Kowloon Building, 555 Nathan Road, Hong Kong.
Tel: 852 2781 3743 Fax: 852 2613 9222
Web Site: www.macron.com.hk e-mail:
Macron International Group Ltd.
The use of our environmental-friendly photocell can keep the circuit design simple too. By comparing with the use of silicon sensors, cadmium sulphide photocells can be used without the need to add an amplifier and a filter glass.
Disadvantages of Using Silicon-based Sensors as Substitute
Another alternative to the existing incompliant cadmium sulphide photocell, which carries 1000PPM to 3000PPM of cadmium, is the silicon-based sensor (photodiode). However, using such sensor is not a wise choice because it requires a completely new set of design. The redesign cost and product cost hence involved can be avoided if our environmental-friendly and RoHS-compliant photocell is used.
In addition, the silicon-based sensor (photodiode) can only replace the existing incompliant photocell on a circuit if some other electrical hardware such as an amplifier is added to it. The photodiode circuit is therefore comparatively complicated. Production cost will then be brought up because the circuit has to be redesigned and extra product / hardware cost will be incurred. Thus it can be seen that photodiode cannot basically replace cadmium sulphide photocell. It is just as undesirable as the incompliant photocell currently in supply.
Policy of Macron International Group Ltd.
Macron International Group Ltd. has been continuously looking for the most suitable and environmental-friendly device to replace the existing incompliant photocell since 2002. We have devoted a vast amount of time, as well as technological and financial resources, to produce a photoelectric component that is beneficial and advantageous to every party. Finally, we have a new photocell that complies with RoHS specifications. This significant development is not only beneficial to the future products, but can also be used to replace old and broken photocells in the old products.
According to the huge consumption of cadmium sulphide photocell around the world, we believe our environmental-friendly and RoHS-compliant photocell can effectively improve the quality of life through a high level of limitation of chemicals with the lowest investment.
To conclude, we earnestly request the EC to reject the exemption requests of incompliant photocell manufacturers in the Annex to the RoHS Directive 2002/95/EC, for the sake of protecting and improving world environment.
Thank you very much for your kind consideration.
Kelvin Cheng
Marketing Manager
Macron International Group Ltd.
Room 703, Kowloon Building, 555 Nathan Road, Hong Kong.
Tel: 852 2781 3743 Fax: 852 2613 9222
Web Site: www.macron.com.hk e-mail: