Development of Hong Kong Photographic and Optical Industry

Recently, Hong Kong Productivity Council (HKPC) has transferred an aspherical glass molding technology to the Hong Kong optical goods manufacturers to improve their competitiveness in the global market. In order to understand more about the history, business and technological development as well as future direction of Hong Kong optical industry, we have specially interviewed Mr. Li Li Man, General Manager of the Manufacturing Engineering Division of HKPC, and also the Chairman of Hong Kong Photographic and Optical industry Group. Mr. Li would also introduce the aspherical glass molding technology and the technical support service on optical industry provided by HKPC.

History of Hong Kong Photographic and Optical Industry

Mr. Li reviewed that the first camera manufacturing company in Hong Kong was set up in 1957, and thereafter, including some Japanese companies also invested and set up factories in Hong Kong mainly for camera and binoculars production. In 1960s, Hong Kong had positioned the top of the world market in binocular production volume. Until 1970s, medium-end camera such as 110, disc, 135 cameras, dominated the Hong Kong photographic goods market. However, only limited local manufacturers in Hong Kong had the capability to manufacture such cameras at that time. The Japanese companies substantially shared our local camera market.

In 1980s, Hong Kong manufacturers started to shift their production plants to mainland and the number of company producing camera and binoculars continuously increased. In 1990s, Taiwan’s camera manufacturers also moved some parts of their production lines to mainland. Nowadays, Hong Kong optical goods manufacturers maintain their activities of design and prototyping in Hong Kong while the mass production process is sited in mainland. The majority of the product are medium to low end cameras including Auto Focus, Auto Wind and manual wind type 135 camera, gift item type and disposable type.

The early relationship between Hong Kong and Taiwan Camera Industry

Mr. Li reviewed that the co-operation of camera industries between Hong Kong and Taiwan had been established for many years. The first camera and binoculars manufacturing company in Taiwan was set up at the end of 1960s which was managed and supported technically by Hong Kong manufacturer. Until early 1980s, Taiwan started to develop its own camera industry mainly cooperated with Japanese joint venture companies for manufacturing OEM product.

Investment by Japan Camera Manufacturers in Hong Kong

As mentioned before, Japanese companies had made investment in Hong Kong and mainland to set up their own factories for camera production. However, after experienced the difficulties of factory management in China, they changed the strategies to issue sub-contract to Hong Kong or mainland manufacturers on the production of medium to low end cameras. Nowadays, Hong Kong camera manufacturers not only develop and manufacture their own brand name’s products, they also manufacture simple components and assemble the cameras for Japanese companies. The critical components, such as lens, shutter, auto focus system, etc., are still imported from Japan. In fact, in view of the increasing camera production volume in mainland, some of the Japanese camera component manufacturers have shifted their production lines to mainland.

Mainland Optical industry finding its way out

In the past, mainland had developed large-scale optical industry driven mostly by the needs of military. However, due to the rising trend of commercial demand, there was an abundant supply of high-skilled labors and experts who started to develop the commercial optical products. Those people had been focusing on manufacturing binoculars before such that they were lack of experience in manufacturing camera, especially the technique in electronics, plastic injection, product design and marketing. In this way, they needed to cooperate with overseas companies to develop the camera business. As mainland provided extensive labour, land resources and low operation cost, nearly all Hong Kong and Taiwan camera manufacturers set up their production plants in mainland. As a result, there is a broad space of cooperation connecting the optical manufacturers of Mainland China, Hong Kong and Taiwan. In fact, the south China region has already become the most important manufacturing base of consumer cameras and binoculars in the world.

Application of Plastic in the Photographic and Optical Industry

Mr. Li reviewed that those early cameras and binoculars, with metal-made case and components, were classified as high precision apparatus. In 1960s, Hong Kong had positioned the top in the world market in binocular manufacture. The local manufacturers then tried to reduce the production cost and increase the production volume by applying plastic on binocular case. It led to the advancement of the plastic technology in binoculars manufacture. Hong Kong manufacturers were indeed earlier than those Japanese manufacturers in applying plastic on the binoculars.

In mid-1970s, in view of the sophisticated development of plastic industry that provided plastic with proven standard in strength and precision, metal was replaced by plastic in some camera components. In late 1970s, medium to low end cameras mainly adopted the plastic components.

In 1980s, due to the evolution of new plastic engineering material and precision injection technology, the performance and functionality of plastic application in optical industry was greatly improved. For instance, using glass fibre re-inforced plastic to produce the case of the camera, the strength was increased while the weight was reduced. The performance of such case was better than that made by aluminium.

The Success of Aspheres in Plastic Lens

The utilization of aspherical lens signed a break through of plastic application in optical goods manufacture. Traditionally, spherical optical lens normally had spherical chromilic abberation. Additional lens were required for correction, and in some cases, 6 to 7 correcting lens were use to achieve high performance requirement.

In 1970s, the first aspherical lens, which could solve the problem of chromilic abberation, was designed in USA using CAD system. However, the aspherical lens could not be produced by traditional method. The earliest aspherical lens was made by casting thermoset plastic in a precisely dimensioned mold, and then processed by fine polishing. As the production process was slow, aspherical lens was only used for high precision requirement. Until mid-1980s, through the rapid advancement of injection technology, aspherical lens could be manufactured efficiently and economically by plastic injection molding with a highly precise mold. At that time, the manufacturers from USA and Japan had successfully implemented the injection technology on aspherical lens mass production for cameras and binoculars. The merits of reduction in production cost and improvement in performance by aspherical lens revealed the potential of plastic lens application in optical industry.

In fact, some Hong Kong manufacturers practiced in aspherical lens injection molding. However, the mold making technology in Hong Kong was not proven in standard that local manufacturers had to purchase the mold insert directly from Japan. In order to promote the quality of Hong Kong optical industry, HKPC, funded by the government, introduced the single-point diamond turning technology in 1995. The technology could achieve up to sub-micron level for product dimension (the surface roughness of machined product is 10nm, equals to 1/7000 of hair diameter). Using the single-point diamond cutter with edge sharpness closed to the diameter of a carbon atom, the machined product did not require further polishing process. Furthermore, HKPC also transferred from USA the CAE system for aspherical lens design and production for local manufacturers.

Bringing together the single-point diamond turning technology, computer aided engineering in aspherical lens and the well-developed plastic injection technique, Hong Kong manufacturers were encouraged to manufacture the aspherical lens. In addition, HKPC also transferred the laser interferometer to assist local manufacturers on product quality testing. The apparatus makes use of optical method to inspect the accuracy and precision level of lens such that it enables the products manufactured by Hong Kong manufacturers to reach the international standard.

Making Mold Insert by Special Material

As diamond cutting with ferrous materiel (containing iron) would chemically damage the cutting tool and the mold, steel made molds are not suitable for aspherical lens production. Mr. Li indicated that aspherical mold inserts could be made by nickel-copper instead of steel. A nickel-copper mold has the advantages of high quality and feasible precision control, but has a poor wearing resistance compared with steel-made mold. Therefore, nickel-copper mold insert is appropriate for small batch production. To achieve mass production of aspherical lens, the steel mold inserts can be plated with nickel layer by electroless nickel plating process. The single-point diamond cutter can machine the plated nickel layer to obtain the requested aspherical shape and precision. This type of nickel layer steel mold has high wearing resistance and good machinability that is suitable for mass production of aspherical lens.

For even larger production volume, tungsten carbide is used as the mold insert and machined by high precision grinding.

Manufacture of High Quality Optical Goods by Glass Lens

Mr. Li stated that optical lens of the highest quality is still made by glass despite of the extensive utilization of plastic lens. The reason is that, while the plastic lens has restricted range of refractive index, the refractive index of glass lens ranges up to several thousand types. In addition, glass lens provides a better stability in optical performance that is crucial and appropriate for high-quality optical equipment, camera and binoculars. However, lens produced by traditional process has a rough surface finishing that requires further fine polishing and lapping. Therefore, HKPC recently transferred the aspherical glass molding technology to achieve one-step glass mold formation without further finishing process. The technology comprises an infrared heating process, and application of precise mold tooling and molding technology. HKPC has installed the necessary equipment and the lens mold is under development. Production of the lens is expected to start up at the beginning of this year.

Plastic Lens used for medium and low-end camera

All the low-end cameras made by Hong Kong use plastic lens. For medium-end cameras, the selection of lens material is determined by functional requirements. For example, for a certain refractive index, glass lens will be chosen instead of plastic lens. In general, plastic lens, especially aspherical lens, would be chosen for medium and low-end cameras.

HKPC provides comprehensive technical support services

Mr. Li said that HKPC plays an important role in providing comprehensive technical support services and training for local optical goods manufacturers, on the aspects of optical design, plastic molding technology for aspherical lens, precision plastic injection molding for small volume production, product quality test and market information etc. HKPC assists the local optical industry through leading-edge technology transfer.

Apart from optical lens, HKPC also provides services on the whole camera manufacture concerning optics, camera body and computer aided design process. Funded by the Government, HKPC has cooperated with several local companies to develop the electronic, optical and mechanical components of power zoom camera. The development of those critical components, is expected to be completed at the beginning of this year, encourages the local manufacturers to manufacture their own power zoom camera.

Diversified Development of Optical Goods

Mr. Li expects a diversified development on the optical industry, especially for plastic lens. At present, Hong Kong manufacturers focus on camera lens and binoculars production. Mr. Li reminds that there is a large potential market for spectacles, such as contact lens, in overseas countries. Hong Kong manufacturers may explore and develop such business opportunities.

On the other hand, traditional camera industry is definitely impacted by the popularity of digital camera that does not require any plastic film. However, Mr. Li believes that such tendency would not adversely affect the local optical industry as the digital camera still makes use of optical lens for image capture.

In addition, Hong Kong optical goods manufacturers have enhanced their product development and application on some other aspects, including camera of computer desktop, optical fibers of IT industry, and office automation equipment such as fax and photocopy machine. There will become profitable growth sectors in optical industry.

Mr. Li said that a number of local manufacturers have been participating in the above-mentioned products production. However, some critical components are still imported from Japan and then assembled locally. The process leads to a low profit margin. Therefore, it is expected to manufacture such critical components locally in order to raise the economical gain. Taking Taiwan as an example, Taiwan manufacturers have been investigating on the development of CD-ROM reading lens, which is conventionally imported from Japan. Mr. Li believes that the local manufacturers also have the capability to develop their own critical components.

In conclusion, Hong Kong optical industry has been developing rapidly, especially for improving the technology of critical component production. Some local manufacturers are planing to cooperate with the mainland upstream manufacturers to upgrade the production technology and product quality. The joined activities can definitely raise the position of Hong Kong in the world’s optical industry.