III. Improvement in Optical Glass Development Processes

Creating New Value through Manufacturing

The Nikon Group aims to improve the efficiency of development and production processes as well as product quality by continuously pursuing the improvements and advancement of core technologies that support manufacturing.
These efforts also contribute to the reduction of the environmental load, such as energy consumption and waste generation.

Economic effect


Lead time of experiments was shortened by 75%.

Environmental effect


Energy for experiments was reduced by approx. 30 tons per year (CO2 conversion).
Amount of waste was reduced by about 103 tons per year.

Optical glass is used for various products such as cameras, binoculars, and microscopes. The required refractive index of optical glass is determined by its function and application and needs to be adjusted with high accuracy of six or more decimal places. As development of optical glass is one of the core technologies supporting the business of Nikon, the Group cooperates to ceaselessly examine and practice improvement measures. Hikari Glass Co., Ltd., which develops and manufactures optical glass, has dramatically improved the efficiency in the development process as a result of these initiatives.

In the conventional development process of optical glass, manufacturing conditions were set by blending the raw materials of glass (composition development) first at a small scale before conducting experiments with large-scale mass production equipment. However, it was not unusual to fail in reproducing the manufacturing conditions set in small-scale experiments during mass production experiments. When melting raw materials of glass by heat in the experiments for mass production, temperatures may be uneven depending on location due to the large size of equipment, resulting in inconsistent components and a reduction in the refractive index and transmission.

Small-scale experiments and mass production experiments had to be conducted again when these types of issues occurred. However, the deficiencies may not have been caused just by uneven temperature. Every process needs to be analyzed individually because problems occur due to combination of various factors; from the type of raw material and blending, measuring, mixing, dissolving and cooling processes. Therefore, it took a long time before actual production. In addition, a large amount of heat energy is used to melt the glass and waste glass is also generated.

The development department of Hikari Glass Co., Ltd. Began to make the process more efficient in coordination with Nikon. We spent one year to meticulously break down the processes, from development design to manufacturing, into small details and analyzed them. We succeeded in obtaining the same results even when conditions such as the scale of equipment differed by optimizing the processes. These efforts have allowed dramatical reduction in lead time of development with higher quality and less cost. In addition, it shorten the time to improve the quality of conventional products and develop new products. Furthermore, this has also proven effective from an environmental perspective such as reduction in the amount of energy consumed and waste generated.

Small-scale experiment
Mass production experiments

Voice of Engineer in Charge of Development

Hiroyuki Abe
Technology Development Dept., Production Division Hikari Glass Co., Ltd.

Aiming for More Efficiency by Utilizing the Results

The manufacturing process of optical glass intertwines multiple layers of various scientific factors and also their structure is invisible. Therefore, it is not easy to identify the factors which affect the quality. Furthermore, we are manufacturing more than 100 different types of optical glass and each of them has its own appropriate manufacturing conditions. As a result, a vast amount of time is required to find the manufacturing conditions for stable production for all types of glass. We completely changed our way of thinking from the conventional way, that is to optimize each glass to the new way, which is to optimize each element technology. We adopted a new methodology and continued research, development, and production design. The technological information discovered by this method can be applied universally for glass in the same category and lead to improvements in efficiency of securing quality and new product development. In the future, I would like to contribute to the reduction of the load on the environment by making research and development more efficient by applying these methods to different category of optical glass that are currently not covered.

Kota Sato
Technology Development Dept., Production Division Hikari Glass Co., Ltd.

Improvement of Technological Capabilities Lead to Reducing Environmental Impact

I felt the need for more efficient technological development while I was involved in projects such as a mass production start-up for newly developed optical glass and a project aiming at quality improvement of existing glass. I came to know a technological development method known as quality engineering (Taguchi method) and employed its techniques to our research process. As a result, we were able to reproduce the same results at a mass production scale as the result we got from small-scale experiments using new evaluation methods. Such improvements in technological capabilities were environmentally friendly and lead to the reduction of the load on the environment, such as reducing the amount of energy and waste. Environmental activities to me is the technological development itself.