TOKYO OHKA KOGYO CO., LTD. (TOK) provides chemical products, such as photoresist, and equipment for semiconductors and liquid crystal displays.

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Environmental Activities

Corporate Social Responsibility

Promotion of recycling, managing chemical substances,
and approaches toward energy saving.

Environment-Friendly Products

TOK is helping protect the environment by supplying products that incorporate exclusive technologies accumulated over many years.

Black Resist

Color filters are essential to the operation of color LCDs. The filter has four colors: red, green, blue and a black matrix. Chrome is normally used to form the black matrix. However, we have eliminated chrome, which is a source of pollution, by replacing it with a black resist.

We have positioned the black resist as one of our strategic products and continue to work on developing black resist products.

Structure of a color filter

*The black matrix is the black border of the lattice containing red, green and blue squares. This black matrix is used to produce an image with greater contrast.


Normally, an LCD glass substrate is coated using the spin process, a method in which centrifugal force is used to apply photoresist evenly to a substrate. In this process, a substrate must be spun at high speed after a drop of photoresist is placed in the center. However, much of the photoresist simply flies off the substrate and is lost. Additionally, spinning substrates consumes a lot of electric power. Another problem is the growing size of these substrates, which makes them more difficult to spin.

To solve these problems, we developed the Spinless® coating technology. Instead of spinning substrates, this technique applies a uniform coating of photoresist by scanning the substrate surface with a slit nozzle. Only the necessary amount of photoresist is applied. For example, this technology cuts the amount of photoresist used on 5-generation glass substrates, which measure 1,100mm 1,250mm, by more than 60%, and cleaning and rinsing solution use is down by 90%, with extremely low power consumption.

*Spinless®: Registered trademark in Japan, No. 4,731,631

The TR130000 S Spinless® coating machine for 8-generation glass substrates

The TR130000 S Spinless® coating machine for 8-generation glass substrates

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