Pioneer of In-mold decoration | YOSHIDA TECHNOWORKS CO., LTD.

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Vol.1 Secrets of Double-sided In-mold Decoration development/The technology that supported the world's first camera-equipped cell phones.
With the evolution of cell phones,
demand for the technology that simultaneously decorates both front
and rear side of the decoration panel of a cell phone has increased.
What brings us to inventing Double-sided In-mold decoration technology,
in the age of Single-sided In-mold decoration technology?
A technology that displays LCD clear

Do you remember the time when cell phones started becoming popular? In the early days, many functions that you find in cell phones today were not exist, and small screens with a black and white display were very common.
However, the features of cell phones have dramatically evolved as time passes. Today, we have cell phones with large screens with color display, and even with features like cameras. Along with these changes in features, the external appearance of cell phones also had to change. Cell phones are no longer the tools only to make calls, but they are now information terminals for reading emails, browsing the Internet, and taking/viewing pictures.
As a result, enhancing the clarity of LCD displays has become a significant challenge.

Find hints from the technology 30 years ago
Find hints from the technology 30 years ago

Cell phone manufacturers approached Yoshida Technoworks about developing a technology to enhance the clarity of digital displays. Initially, we applied dipping process to a product in order to achieve a clearer display screen on the product with AR (anti reflection) evaporation.
However, dust got stuck on the display screen in the initial mass production, and the yield ratio was as low as only 10%.
In order to overcome this challenge, Mr.Shimoyama developed Double-sided In-mold decoration process, which effectively decorates both sides of the device's surfaces.
Though different from the current process, we had applied the printing technology on both surfaces to the prototype production of a top plate of cosmetic compact case about 30 years ago. With this experience, we started developing our new technology.

Continuous failure, the plant got flooded

Double-sided In-mold decorations could simultaneously decorate both front and back side of the surfaces of a plastic product. Instead of rapping as the secondary process, AR and UV coating could be deposited at once, if we use the technology practically. This would ensure that dust particles and dirt will not be sticking on the screen as provide a clear LCD display maintained.
This type of in-molding, however, had many high level technical issues compared to Single-sided In-mold decoration. The biggest challenge was how to inject the resin between the front and rear in-mold foil. "We experienced failure many times. We have even flooded the floor of the plant," said Shimoyama referring back to his challenge. How can we successfully inject the resin? After numerous trials and failures, his team finally found the solution, wherein the resin was injected into a hole made on the in-mold foil of the back surface. This worked out to be successful, and the method was established as Double-sided In-mold decoration.

Used in the world's first mobile phones with cameras.
Used in the world's first mobile phones with cameras.

With this Double-sided In-mold decoration technology, cell phones with a built-in camera were manufactured for the first time in the industry. The display needs to be much clearer for a devise equiped with a camera.

This will be possible with Double-sided In-mold decoration technology. Moreover, it requires less process steps.
The world's first camera-equipped cell-phone launched in November 2000, astonishing the world market. Soon other manufacturers followed the feature, and a phone with camera has become very common. The Double-sided In-mold decoration technology invented by Yoshida Technoworks actually supported the creation of this innovative product.

The Double-sided In-mold decoration enables a great variety of new designing, and is now used in the production of a wide array of products. The pioneer of in-molding, Yoshida, has even created the newer in-molding legend.

Yoshida Technoworks Co., Ltd.
TEL.+81-3-3610-0081(Office Hour : Mon - Fri 8:30-17:20)
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