To Create Air of the 21st-Century

In 2000, Sharp developed Plasmacluster technology to purify air. Its efficacy in preventing the action of airborne molds and viruses, as well as in reducing the effects of airborne allergens has been verified*1. This technology has been utilized in air purifiers and ion generators as well as in numerous other products. What's more, Plasmacluster technology is deployed in a variety of industrial products and in transportation facilities, such as cars and trains, as well as in offices, factories, and hotels.

Throughout the years, Plasmacluster technology has purified the air. In this challenge, Sharp sought to improve the quality of air in bathrooms, an area many people would like to freshen up.

Nankai Electric Railway Co., Ltd. Providing comfortable transportation service to customers.

Aiming to Improve Bathroom Air Quality

Bathrooms are one of a home's top locations for unpleasant odors to occur. Based on our survey, many cases were found where bathroom windows were rarely opened due to security and privacy concerns. And many people use bathroom ventilation fans only during the short time that they are in the bathroom.

Plasmacluster Ion generators are ideal for solving air quality issues in places like bathrooms, where the air is stagnant. Feedback from Sharp customers, however, indicated that limited installation space, problems regarding power outlets, and power cords getting in the way made ion generators difficult to use in the bathroom, even for customers who are eager to try them there. And although Sharp has already introduced ion generators that run on portable batteries, the batteries need to be charged or replaced, leaving some inconvenience for continuous use.

After careful consideration, Sharp came up with the idea of using the light socket in the bathroom ceiling. Sharp's development team also took into account that an ion generator installed to the ceiling could generate a high concentration of Plasmacluster Ions from overhead. This led Sharp to undertake the challenge of developing a ceiling-installed Plasmacluster Ion generator.

* Picture may vary from actual vision.

Pinpointing a Solution to Air Issues

The distinctive unpleasant odors of a bathroom are caused by odor-causing bacteria adhering to surfaces such as floors. Plasmacluster Ions can sterilize*2 and deodorize these adhering, odor-causing bacteria and keep bathroom air clean.

Since adhering, odor-causing bacteria cling to surfaces such as the floor surrounding the toilet, Plasmacluster Ions must be dispersed from the ceiling all the way to the floor. For this reason, adjustments had to be made to the wind direction, fan strength, position, and other aspects of the Plasmacluster Ion generator unit as well as to individual parts, such as the fans. In addition, the product had to be made lighter and more compact to comply with the standard E26 cap shape. Since this model would also include an LED light, heat generation had to be suppressed and materials had to be made durable, making the designing phase extremely difficult.

  • *2Elimination of bacteria: Effect after 7 days in a test space of approximately 3.4m3; not a proven result in actual usage space.

Enhancing the Product with Motion Sensors

To further improve customer convenience, Sharp continued to review the product.

Typically, bathrooms are vacant for much longer periods of time than they are in use. To effectively utilize the time when bathrooms are not in use, a motion sensor was installed that automatically turns on the generator's LED light when anyone enters. When the bathroom is empty, the light turns off, and Plasmacluster Ions are generated in maximum mode. This way, we thought it would actually be better able to notice how comfortable the air has changed. And of course, an LED that automatically lights up is much more convenient than conventional bathroom lighting.

Aside from working on the ceiling-installed Plasmacluster Ion generator itself, Sharp put much effort into other aspects as well. For example, since use of the motion sensor requires that the light switch on the wall be turned on at all times, a sticker is included to the product warning users not to turn the switch off.
In addition, flyers indicating the actual size of the ion generator were created. Customers who are considering purchasing the product can take a flyer home, see the product's actual size at a glance, and check whether it is a good fit for their bathroom.

Image of measuring ion concentration using ion counter.

Verifying Product Performance

To prove how well the ceiling-installed Plasmacluster Ion generator performs in bathrooms, Sharp needed to verify that adhering, odor-causing bacteria were properly eliminated from the bathroom.

The superior efficacy of Plasmacluster Ions has been verified by the world's leading science research laboratories in not only Japan but also the UK, the US, and Southeast Asia*1. However, the size of a bathroom made it difficult to have efficacy verified by a general testing organization. Therefore, Sharp searched for a facility that could carry out such verification.

Sharp asked Shokukanken Inc. to conduct tests by actually assembling a bathroom space in a testing environment and installing the Plasmacluster Ion generator on the ceiling. Shokukanken Inc. has vast experience in the testing of microorganisms and also has expertise in advanced environmental testing. Test results on samples of odor-causing bacteria clinging to the floor showed the sterilization of bacteria*2.

  • *1Please refer to Sharp's website for information on PCI efficacy verification. (
  • *2Elimination of bacteria: Effect after 7 days in a test space of approximately 3.4m3; not a proven result in actual usage space.

Making the Air of the Entire House Clean

Driven by a determination to purify the air of the entire house, Sharp is developing various products equipped with Plasmacluster technology. As a result of this particular Sharp undertaking, a ceiling-installed ion generator was developed to improve air quality in the bathroom, where no extra power outlet could be expected.

Sharp offers a wide array of Plasmacluster Ion generators to purify the air, including the ceiling-installed type, bedside type, automotive type, personal humidifier type, and portable moisturizing type. Such products have contributed to purifying the air in various parts of the home.

Sharp will continue to tackle challenges to purify air with Plasmacluster technology.

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