Characteristics of Anti-fogging Coating

Performance evaluation of antifogging coating

Proposal for cover glass for a surveillance camera (critical comparison with distributed market product)

Surveillance cameras are installed in a variety of indoor and outdoor locations. They are often used in harsh, outdoor environment, where changes in the surrounding environment (humidity, temperature, rainfall, backlighting) can make it difficult to capture accurate image information. A comparative evaluation of NSG's antifogging coating (coated type) and the antifogging treatment (coated type) used in market surveillance cameras was performed.

(1) Comparison evaluation method
This was a comparison of the antifogging performance, antifogging durability, and wear resistance with antifogging coated cover glass of market surveillance cameras　

(2) Evaluation results
NSG's antifogging coating is superior in terms of water durability and abrasion resistance, and shows excellent performance in terms of antifogging durability that is expected in cold areas and coastal regions.

Main uses and applications

Development of antifogging coating used for plastic substrates

The main purpose of the NSG’s development of antifogging coatings is to use with antifogging properties to glass substrates. There is also parallel development taking place for antifogging coatings for plastic substrates (PC and PET resins).
As PC resin, which has excellent optical properties, is an injection molded, it can be used in various optical components, including CCM optical lenses and pickup lenses, surveillance camera cover glass, and automobile headlights, as well as optical lenses for glasses and sunglasses. However, it is also a resin that is difficult to achieve adhesion for surface treatment.

Evaluation Results
The antifogging coating of NSG can be used to form a durable antifogging film on PC sheets.

Glossary

Antifogging coating

This means that an antifogging coating is attached to cover the surface of the substrate.

Antifogging

Glass and plastic become fogged when the temperature of the surface drops below the dew point and, in this situation, moisture in the air adheres to the surface as fine water droplets. This causes the diffuse reflection of light. By controlling the state of moisture adhesion, light scattering is suppressed, preventing the fogging phenomenon. One example of the antifogging technology is the hydrophilic and water-repellent treatment of material surfaces. Various antifogging technologies have been developed to prevent the fogging of material surfaces.

Visibility

This indicates the degree to which an object can be seen visibly with the eyes. High visibility means the object can be seen in detail.

Exhalation

This refers to expelling air from the lungs through the mouth and out of the body. The antifogging performance can be simply checked by blowing air through the mouth and to see if the antifogged surface becomes foggy.

Advanced Driver Assistance System (ADAS)

ADAS is short for advanced driver-assistance systems. It is a general term used for systems that monitor information about their surroundings, control driving operations, alert the driver, support comfortable driving, and prevent accidents. ADAS is a general term for systems that support comfortable driving and prevent accidents. The system supports "cognitive," "judgmental," and "operational" functions when driving.

Surveillance system

A surveillance camera system does not refer to just one surveillance camera, but instead refers to a system that connects multiple surveillance cameras via a network with the aim of managing and storing video and audio.
With such advances in technology, it is now possible to deal with large amounts of data, and for this, it is better to monitor with a surveillance camera system rather than a single surveillance camera.
Remote monitoring systems and centralized monitoring systems, which are advanced monitoring systems, are being utilized.

Personal authentication

As IT has advanced, we are seeing a rapidly growing need to be able to identify (personally authenticate) users when they use or log into devices or systems. A personal authentication system identifies whether the person attempting to use the device or system is the same person who previously registered. It is possible for companies to handle the private information of people and companies securely using these personal authentication systems. mage data (physical characteristics = fingerprints, face, hand veins, etc.) are often used as means of personal authentication.

Compact Camera module (CCM)

A Compact Camera Module (CCM) is a device for industrial use with a structure similar to that of a consumer-use single-lens reflex camera. A lens and a camera make up this camera module. In the CCM, light entering from the lens is projected on to the photographic element and converted into electrical signals to obtain images. There are two types of camera elements, CCD and CMOS.

Sol–gel technology

The sol–gel method is a method in which starting materials are made out of a solution containing inorganic materials, organometallic salt materials, etc., following which the solution is hydrolyzed and condensed to form a colloidal solution (sol state). Thereafter, the reaction is accelerated to form a solid (gel state). Further, it is heat-treated to produce high-purity glass or ceramics.

Hybrid technology combining inorganic and organic materials

This technology involves combining organic and inorganic materials at the molecular level. This then creates structures (bonded and unbonded) with both organic and inorganic material characteristics.

Light scattering

Light travels straight in an even medium. The direction of light may change, however, if the medium is uneven. In general, we call “light scattering” the phenomenon in which the direction of light travel changes in an irregular manner as a result of small water droplets or fine particles that do not allow light to pass through in the direction of travel.

Spin coating

Spin coating is when a thin film is formed on an object by using a spin coater to put a certain amount of liquid on the top surface of a flat coating object, following which the centrifugal force that can be generated by rotating the object at high speed is used.

Dip coating

Dip coating refers to the formation of a thin film on an object by dipping the object to be coated into a liquid vertically and then adjusting its viscosity, surface tension, gravity (gravity of the flowing down of the adhering liquid) and liquid velocity. This enables the object to be pulled up and coated and the film thickness to be controlled.

Spray coating

In this process, a spray coater is used to form a thin film on an object by atomizing (misting) a liquid and spraying it onto the object to be coated.

Water film formation

This refers to the phenomenon in which a thin layer of water forms on the surface of an object.

Dew point

This is the temperature at which water vapor in the air becomes liquid (fog) after it is cooled. The saturated water vapor content is the limit amount of water vapor that can be contained in the air at a certain temperature, and if that amount (saturation state) of water vapor is exceeded, this appears as fog. The temperature at this time is the dew point (dew point temperature).

Image sensor

The process of capturing images with a digital camera involves converting the light of the subject entering through the lens into digital image data before outputting it. The data is converted in the part known as the image sensor. There are two types of image sensors, CCD (Charge Coupled Devices) and CMOS (Complementary Metal Oxide Semiconductor). The elements that make up a CCD image sensor can be broadly classified into a light collecting lens, a color filter, a photodiode (light receiving element), and a transfer circuit. The performance indicator in digital cameras is the number of pixels which relates to the number of photodiodes. CMOS image sensors have a pair of amplifiers per photodiode. In CMOS image sensors, each photodiode is paired with an amplifier. The charge from each element is amplified before it is transferred to the image processing section, which makes it less susceptible to noise during the transfer process.

Image sensor

The process of capturing images with a digital camera involves converting the light of the subject entering through the lens into digital image data before outputting it. The data is converted in the part known as the image sensor. There are two types of image sensors, CCD (Charge Coupled Devices) and CMOS (Complementary Metal Oxide Semiconductor). The elements that make up a CCD image sensor can be broadly classified into a light collecting lens, a color filter, a photodiode (light receiving element), and a transfer circuit. The performance indicator in digital cameras is the number of pixels which relates to the number of photodiodes. CMOS image sensors have a pair of amplifiers per photodiode. In CMOS image sensors, each photodiode is paired with an amplifier. The charge from each element is amplified before it is transferred to the image processing section, which makes it less susceptible to noise during the transfer process.

PC sheets, PC resin, PC resin substrate

This is a board-shaped substrate made of polycarbonate resin used for applications that require transparency and impact resistance.

PET film, PET resin, PET resin substrate

This is a film made from polyethylene terephthalate resin that is used for applications requiring strength and durability.

Processing method

Liquid

Antifogging coating

Others