Luminescence literally is a light that shines in the darkness of night. Luminous paint is produced by mixing phosphors (a phosphorescent pigment), which are characterized by emitting a stored light, in ink. The afterglow performance of phosphorescent pigments at the time of company foundation was low, and light was emitted by constantly activating the phosphorescent pigment through alpha rays emitted by a radioactive substance such as radium and by mixing such substance in the phosphorescent pigment. Kenzo thought that the demand for luminous paints for watches and clocks would expand during the war as lighting was restricted at that time. However, the demand during the war was almost entirely for military use such as painting on meters and gauges in aircraft and submarines. Luminous paint lights were not used at ordinary residential houses. As a result, Kenzo temporarily lost his job after the end of the war.
At the same time, this provided a golden opportunity for Kenzo to provide luminescent brightness to ordinary residential houses. Kenzo hit on the idea of painting luminous paint on the numerals and hands of watches and clocks to allow one to tell the time even at night. Kenzo took this idea to Seiko, a corporation of watches and clocks, and asked Seiko to “let him paint luminous paint on the dial plates of clocks.” After receiving the dial plates of clocks from Seiko, Kenzo would paint luminous paint on dial plates in a small workshop next to his house. Kenzo started work by delivering clocks painted with luminous paint to Seiko. Parallel with the economic reconstruction after the war, the production of clocks for ordinary houses increased drastically and the workload also increased for Kenzo. It meant Kenzo was able to offer luminescent light, which enthralled Kenzo himself, widely in a peaceful world. Kenzo steadily expanded his business and the unique technology developed by Kenzo to regenerate degraded phosphorescent pigments that could not be used also contributed to this.
In 1948, Kenzo founded the Nemoto Photo Chemical Laboratory as a partnership firm, which was reorganized in 1962 into the present company form as Nemoto & Co., Ltd., the current corporate name. Through an organizational reform conducted in June of 2012, the businesses of Nemoto & Co., Ltd. were transferred to the group companies. The watch and clock business, which has been the core business since its foundation, remains in Nemoto & Co., Ltd. In cooperation with the manufacturers of watches and clocks inside and outside of Japan, the Company will continue to develop and process products for watches and clocks that better suit consumer needs.
Luminous paints in the early days emitted a light by constantly activating a zinc sulfide based phosphorescent pigment using a radioactive substance such as radium. Since then, the radioactive fallout incident in 1954 involving No. 5 Fukuryu Maru fishing vessel in the South Pacific triggered concern among the public about the hazard of radiation problems on the human body, prompting the enactment of laws and regulations on the handling of radioactive substances. Nemoto & Co. has continued its business while fully complying with these laws and regulations.
In 1960, Nemoto & Co. developed N-Hakko, a luminous material featuring safety in use and a low level dose of radiation by emitting lights through promethium, a radioactive isotope. From 1962, the high-volume production of N-Hakko started and the product was supplied to its customers. In 1973, Nemoto & Co. developed a long afterglow zinc sulfide based phosphorescent pigment (GSS series) by modifying its zinc sulfide based phosphorescent pigment itself. As the Japanese manufacturers of watches and clocks moved their production operations to China in the 1970s, Nemoto & Co. established a joint venture company in Hong Kong in 1978 and has expanded its global operations since then.
“Luminous paint technology” is the core technology of the Nemoto Group. Fostering its unique technology based on the “luminous paint technology,” Nemoto & Co. has been active in expanding its global business operations. More than 70 years since the establishment, the manufacture of phosphorescent pigments has been transferred to Nemoto Lumi-Materials Co., Ltd., while the technology to handle radioactive materials that brighten phosphorescent pigments has been succeeded to by Nemoto Sensor Engineering Co., Ltd. and Nemoto Science Co., Ltd. The technology to print and paint luminous paint onto the dial plates of watches and clocks has been transferred to Nemoto Precision Co., Ltd. These subsidiaries receiving the Nemoto technologies are Nemoto Group companies and NEMOTO products are now widely used on a global scale.
In 1993, Nemoto & Co. succeeded in developing an epoch-making new phosphorescent pigment LumiNova®. The new pigment is not only free of radioactive materials, which has been a long-cherished desire of the Company, but also features a luminous intensity ten times brighter than those of conventional zinc sulfide based phosphorescent pigments. The new material continues to emit a light ten times longer and is indeed “A dream luminescence.” This LumiNova® was a grand discovery made possible by a strong intention to continue the watch and clock business, while the Japanese manufacturers of watches and clocks made efforts to free themselves of radioactive materials. LumiNova® has been welcomed inside and outside of Japan and is now used extensively in a large variety of applications aside from watch and clock applications. In 1993, LumiNova® was awarded the NIKKEI Grand Prize for an excellent product and service category, as well as the coveted Okochi Memorial Technology Award, in recognition of its technological uniqueness.
In the several years since its debut, LumiNova® has succeeded in replacing luminous paints that used radioactive materials. The elimination of radioactive materials has enabled completely coating a dial plate with luminous paint, in addition to numerals on the dial plates of watches and clocks.
A local corporation and joint venture company have been established in Switzerland, a leading watch and clock producing country of the world, to manufacture and sell LumiNova® of a special-purpose grade to the domestic watch industry.