月: 2023年2月

What Is a Graphic Panel?

A Graphic Panel is a panel that displays a structure. It is used as one of the devices that make up the central monitoring system.

It displays on a large screen the system diagrams and layout diagrams of the power system, air conditioning and ventilation equipment, water supply and drainage equipment, etc., of the power receiving and transforming facilities installed in the automatic control equipment, and expresses the equipment operation status and measurement values on the screen.

Uses of Graphic Panels

Graphic Panels are used for a variety of purposes, including the display of information and images.

1. Uses in the City

For example, they are used for sightseeing information bird’s-eye view signs, 360° panoramic bird’s-eye view signs, and large panels for conference rooms. They are also used for various purposes in traffic control systems such as railroads, for example, to indicate the position of vehicles with lamps.

Other applications include arrival and departure information at airports and train stations, and score displays at concerts and sporting events.

2. Hazard Avoidance Applications

To indicate the alert and monitoring status of a facility, a floor plan of the facility can be inserted into the panel board, and the alert status transmitted from various sensors can be controlled by the controller and indicated by lighting and blinking LEDs. The easy-to-see, easy-to-understand display enables early detection of intruders and prompt response.

3. Applications at Construction Sites

Graphic Panels are also suitable for advertising and promotional use for construction projects at construction sites. By displaying them in highly visible locations throughout the site, they can provide project information to passersby and interested parties.

Graphic Panels are also useful for providing instructions and safety reminders within the construction site. Displaying information about heavy equipment and hazardous work areas can help prevent accidents.

They can also indicate the progress of a construction project, which improves communication among all parties involved, streamlines operations, and facilitates project scheduling.

Principles of Graphic Panels

Graphic Panels, a type of display technology used to show information, differ from conventional display technologies such as liquid crystal and plasma displays in that they use a material called OLED, which utilizes organic molecules.

OLED has the property of emitting light when electricity is applied, eliminating the need for a backlight, as is the case with LCDs, and making it possible to create thin, lightweight displays.

It also features a very wide range of display colors, high contrast ratio, and wide viewing angles. While these panels are very useful for guiding and explaining facilities to visitors, the cost is relatively high because separate monitoring and display devices are required.

When used as a map panel, it can be classified into two types according to the display method: the simple method and the engraved method.

1. Simple Method

The simple method of Graphic Panels uses light-emitting diodes (LEDs), which are arranged directly on the surface of the panel and emit light. This method uses a method called dot matrix to connect the dots, and although it cannot produce a high-definition display, it can be manufactured at a low cost.

It also consumes less electricity and is highly energy-efficient. 

2. Engraving Method

In the engraving method, the panel surface is engraved with a laser to allow light to pass through. When the laser beam hits the panel surface, it vaporizes the surface and creates microscopic depressions. The light is scattered by these depressions and the specified design appears on the surface of the panel.

This method enables higher definition display by controlling the engraving depth and light transmittance. While it has a high level of design and visibility and is visually appealing, it is also burdensome in terms of cost and delivery date if the screen display needs to be changed.

When specifications change due to an increase in the number of monitoring devices or a change in their location, it is necessary to create a new map version and change the internal wiring and the location of the LEDs on the back of the screen to update the screen display, which tends to increase the cost. As a countermeasure to such high costs, a recent trend is to use software-generated monitoring screens projected onto large LCD monitors instead of handmade panels, and to use general-purpose Internet browsers or dedicated applications for monitoring.

Characteristics of Graphic Panels

The production of graphic panels requires a high level of technology and expertise. Although they are more expensive, they can be easily installed to monitor the equipment system of an entire facility.

Various monitoring alert statuses, equipment operation statuses, and fault occurrence statuses can be checked and grasped graphically on a map version, contributing to quality improvement of facility management. In addition, it is necessary to select the most appropriate materials and technologies according to the intended use and location, thereby realizing cost reductions.

• What Are Ion Generators?

Ion Generators are devices that generate ions using electricity, mechanical power, or ultraviolet light.

Ions generated by an ion generator are used for various purposes, such as sterilization, static electricity removal, and dust collection.

In order to generate ions, there are methods of generating negative ions by causing corona discharge to generate plasma, generating negative ions by the photoelectric effect, and a method called the Lenard effect.

Uses of Ion Generators

Ion Generators are widely used in homes, public facilities, hospitals, and factories.

Examples of uses include installation in air purifiers to sterilize mold and other harmful microorganisms, applying positive and negative ions to areas where static electricity is generated to eliminate static electricity, and collecting static-charged dust by means of the generated static electricity.

When selecting Ion Generators, it is necessary to consider the amount of ions generated, the ratio and precision of positive and negative ions, the power used, and ease of maintenance.

Principle of Ion Generators

The operating principles of Ion Generators is explained separately for the corona discharge, photoelectric effect, and Lenard effect.

The ion generator consists of an ion generator and an ion transmitter. In the ion generator, ions are generated by electricity, photoelectric effect, and Lenard effect. The ion transmitter transports ions by blowing air.

• Corona discharge
  High voltage is passed between a needle-shaped electrode and a flat plate, and air is sent between the electrodes to cause corona discharge, which generates plasma at the electrode tips and produces positive and negative ions. Only negative ions are transported since positive ions are then absorbed by the electrodes.
• Photoelectric Effect
  The structure consists of a light-emitting object, such as an ultraviolet lamp, surrounded by a photoelectron-emitting material. During operation, a gas and air that have a high affinity for photoelectrons are sent into the device to ferment the luminous body, and the light causes the photoelectrons generated from the photoelectron-emitting material to combine with the gas that has a high affinity for photoelectrons, generating negative ions.
• Lennard Effect
  The system consists of a pump, an impact generator, and a transport section. Water supplied from the pump is turned into minute droplets by the impact generators, at which time negative ions are released into the air. Ions are taken out by transporting the negative ions.

Effects of Ion Generators

Ion Generators have been attracting attention recently with the increase in hygiene awareness, and are now installed in many places such as homes, offices, hotels, and public facilities.

Ion generators use water and oxygen in the air to generate positive and negative ions, and the ions change into OH radicals, which have a bactericidal effect, decompose organic matter, and eliminate bacteria and deodorize the air.

Air purifiers are equipped with dust collection filters and deodorizing filters to take in dirt in the air to clean the air, but Ion Generators clean the air by generating ions that are effective in suppressing the action and growth of airborne mold bacteria and viruses.

It also decomposes and removes mold fungi and viruses attached to the room, as well as tobacco odors on clothes, sofas, and other surfaces. For this reason, it is gaining popularity among households concerned about pet odors and nursing care workers concerned about hygiene. In addition, it is said to have the effect of suppressing static electricity and giving the skin a glossy effect.

On the other hand, although the ion function has an image of being “good for your health,” some people are concerned about the effects of ozone, which is generated at the same time as ions are generated. Manufacturers however state that ozone generated is so small that it has no effect on the human body, but no numerical values ​​have been disclosed.

Ion Generators for Commercial Use

Planning and consulting services are available for commercial negative ion generators to provide total support, from installation to maintenance, in accordance with the site environment.

The main support includes a preliminary survey of the installation environment and proposals on the model, number of units, and installation location suited to the workplace conditions. We then verify the effectiveness of the system by simulating how much ion concentration will be achieved in the space and measuring the number of airborne bacteria.

The types of commercial products include floor-mounted types for large spaces of approximately 65 m² (about 39 tatami mats), easy-to-install wall-mounted/shelf-mounted types, and static eliminators specialized for static elimination.

There are also special air conditioning duct-integrated ion generator systems. This system is designed to be stored in the existing air conditioning vent space without changing the image of the room.

What Is Graphite Sheet?

As electronic devices such as mobile devices become lighter, thinner, and smaller, and at the same time, more advanced and sophisticated, the problem of heat generation is becoming more serious.

The thermal conductivity of graphite sheets is two to five times that of copper, which has the highest thermal conductivity among metals, and although slightly lower than that of diamond, it is higher than that of other metals. It is expected to be a heat countermeasure material that has excellent heat conductivity (heat dissipation and heat diffusion) and is both thin and flexible.

PGS (PGS = Pyrolytic Graphite Sheet) is known as a domestically produced crystalline graphite sheet with high thermal conductivity and flexibility (registered trademark of Panasonic Corporation).

Uses of Graphite Sheet

It is highly effective for heat diffusion and dissipation in various applications including mobile electronic devices.

Graphite sheets are used in semiconductor manufacturing equipment (sputtering, dry etching, etc.), optical communications, and base stations, in addition to home appliances such as smartphones, cell phones, digital cameras, tablet PCs, PC peripherals, and LED devices.

Graphite sheets are also used as a heat-resistant material in various fields other than those mentioned above, and the market is rapidly growing.

Principle of Graphite Sheet

Simply put, the manufacturing process for graphite sheets involves a very simple principle: a polymer film with a special molecular structure is thermally decomposed at high temperatures and then fired at ultra-high temperatures to create a highly oriented crystal structure in the planar direction that resembles a single crystal.

However, this special raw material is a trade secret, and we cannot explain why graphite is formed when this special raw material is used.

Then, why is high-temperature processing necessary? There is a clear answer here.

When polymeric materials containing carbon are heated under oxygen-free conditions:

Hydrogen at 500°C

Oxygen at 1000°C

Nitrogen at 2000°C

and finally, when heated to 3000°C, only carbon atoms remain. The carbon atoms are calcined and crystallized into high-quality graphite crystals.

Due to this layered structure, the thermal conductivity of graphite sheet is characterized by the fact that heat is hardly transferred in the direction of thickness, but is quickly transferred in the direction of creepage.

In addition, the graphite sheet does not require complex manufacturing processes and can be produced at a low cost.

What Is a Crosscut Saw?

A Crosscut Saw is an industrial machine that uses a rotating circular saw directly connected to a motor to cut the material to be processed on a stand.

Crosscut Saws are used for horizontal cutting operations on long, large pieces of wood or aluminum, usually in conjunction with a long horizontal stand.

The diameter of a mainstream circular saw is roughly 400 to 600 mm. There are two types of circular saws: one uses a scale to visually determine the cutting point, and the other uses a digital device that automatically determines the cutting point by punching in the dimensions.

The scale type requires the skill and experience of the craftsman, while the digital type is more accurate.

Crosscut saws are often used on construction sites and in furniture manufacturing plants. They are also popular among DIY enthusiasts and suitable for home processing operations. Efficient work is possible by changing the shape of the cutting edge and blade material according to the material to be processed and the cutting point.

On the other hand, crosscut saws have rotating cutting edges and can be dangerous, so it is important to take appropriate safety precautions and use them correctly.

Uses of Crosscut Saws

Crosscut Saws are used in woodworking, metalworking, and DIY.

In woodworking shops, crosscut saws are used to cut square timbers into horizontal cuts when working with long, large pieces of wood.

They are also used by metalworkers to cut aluminum and other materials. Therefore, they can also be applied in construction sites and automotive plants.

Furthermore, crosscut saws are also used in private wood workshops and studios, as some sizes can fit on a tabletop space.

For woodworkers and DIY enthusiasts, they are indispensable machines for improving the precision and speed of cutting operations.

Principle of Crosscut Saw

There are two main types of crosscut saws: manual-feed and automatic-feed, and their principles are different, so it is necessary to select one according to the application.

The manual feed type crosscut saw consists of a rotary saw directly connected to a motor that moves back and forth, vertically and horizontally, and cuts the material placed on a table while pulling it.

The automatic feed type crosscut saw consists of a rotary saw mounted on a motorized rotary shaft, and the saw is moved by stepping on a pedal to cut the work piece. The width of the cut (distance traveled by the work piece) is adjustable, as is the speed at which the saw is moved.

Unlike other circular saws, the crosscut saw is a down-cutting saw, which means that chips are scattered forward when the material is cut, allowing for safe and efficient work.

There is also a model called an optoelectronic jumping crosscut saw that can cut off only the part of the material that is unnecessary by drawing a line with a special chalk in advance and using a special detection device, enabling more efficient and accurate cutting.

Types of Crosscut Saws

There are various types of crosscut saws, but the two most common types are sliding crosscut saws and mini crosscut saws. Each has different characteristics, so selection should be based on the intended use.

1. Sliding-Type Crosscut Saw

Slide-type Crosscut Saws are capable of cutting a wide range of boards by sliding the head equipped with a blade up and down. They are often used in large factories or on job sites, and their large cutting capacity makes them suitable when long lengths of material need to be processed. The angle of the processed material can also be adjusted, enabling diagonal cutting.

Slide-type Crosscut Saws are used for processing wood, plastic, aluminum, steel, etc., and can cut a wide range of materials.

2. Mini Crosscut Saw

Mini Crosscut Saws are characterized by their small size, light weight, and compact design. Its table-top size makes it suitable for small workshops and DIY enthusiasts. Although its cuttable size is small, it is highly accurate and is used for processing resin, wood, and metal. In addition, mini crosscut saws are inexpensive, making them easy to purchase even for beginners.

What Is an Ammonia Meter?

An Ammonia Meter Is a Device to Measure the Amount of Ammonia in Water

Ammonia Meters are devices that measure the amount of ammonia in water.

Ammonia Meters are used to analyze industrial wastewater and the amount of ammonia in rivers, lakes, and seawater, as ammonia is a compound that is restricted from being released into rivers as wastewater.

Ammonia Meters Are Fitted With Electrodes

Ammonia Meters are equipped with electrodes to detect ammonium ions. The electrodes must be cleaned after each use, as contamination of the electrodes can cause fluctuations in readings. In addition, the electrodes for ammonium ions and the comparison electrode are consumables and must be replaced periodically.

Applications of Ammonia Meters

Ammonia Analysis of Wastewater and River Water

Ammonia is a compound whose discharge into the environment is restricted. Therefore, Ammonia Meters are used to control the amount of ammonia contained in industrial effluents and for environmental analysis of rivers, lakes, and seawater.

The small size of the Ammonia Meter makes it possible to collect wastewater samples on site for simple on-the-spot analysis.

Also Used in the Design of Ammonia Decomposition Processes

Ammonia Meters are also used in sewage treatment plants and wastewater treatment plants that decompose and treat ammonia.

Ammonia Meters are used to measure the amount of ammonia in wastewater before and after biological treatment to control the amount of ammonia and to design optimal processes.

Features of Ammonia Meters

Ammonia Meters Are Equipped With a Membrane and Electrodes

An Ammonia Meter is a device that quantifies the amount of ammonia from the amount of ammonium ions in water. The amount of ammonium ions is calculated from the potential difference between an electrode containing a membrane that selectively transmits ammonium ions and a comparison electrode.

Since potassium ions, which are also cations, act as interferents for the ammonium ion electrode, the Ammonia Meter is also equipped with a potassium ion electrode for compensation.

Check the Electrode Surface for Contamination Before Use

Ammonia Meters are used to measure aqueous solutions containing a variety of substances, such as river water, industrial wastewater, and sewage. Therefore, if the Ammonia Meter is immersed in a sample for a long period of time, contamination will accumulate on the electrode surface.

The electrode must be replaced periodically because the accumulation of contaminants causes fluctuations in the measured potential difference. Some devices have a built-in ultrasonic oscillator, which can remove dirt and scale from the electrode surface.

Ammonia Meters are also available that constantly immerse the electrode in a sample solution and output data on ammonia levels, as monitoring of ammonia levels over time is necessary for some applications.

What Is a KVM Extender?

A KVM extender is a device that allows you to use your keyboard (Keyboard), display (Video), and mouse (Mouse) at a distance from your computer.

Typically, the cable connecting the keyboard, display, and mouse (KVM station) to the computer is designed to be no longer than about 10 meters. Using a cable longer than about 10 meters will result in digital signal attenuation and waveform distortion, which will prevent proper data transfer.

With KVM extenders, connections can be made over CATx cables up to about 150 meters, and even farther over fiber optics or networks, while maintaining the quality of the digital signal.

Uses of KVM Extenders

KVM extenders are primarily used to isolate computer units from human view for security and maintenance reasons.

1. To Streamline Work in a Server Room

KVM extenders allow users to operate servers from a remote location without entering the server room. Server room staff does not need to physically approach the servers. This reduces the burden and travel time of the server room staff.

2. To Make the Best Use of Desktop Space

With a KVM extender, the PC itself can be removed from the desktop. This not only saves desktop space but also simplifies wiring and maintenance.

3. For Security Purposes

With a KVM extender, the main computer unit can be protected by surveillance cameras and locks. This prevents leakage or tampering with confidential information or important data.

4. When Securing the Computer’s Operating Environment

Computers can be installed in a secure and stable environment away from outdoor live event venues with huge screens.

Principle of KVM Extenders

A KVM extender is a mechanism that physically separates a computer from its keyboard, monitor, and mouse, converts the signals between them, and transmits the signals over long distances via CATx or The KVM extender is placed between the computer and the keyboard, monitor, and mouse, converting the signals and transmitting them over CATx or fiber cables that can carry data over long distances.

KVM extenders can be connected to multiple computers over a network, as well as one-to-one connections. In this case, a technology called KVM over an IP extender is used.

Types of KVM Extenders

KVM extenders are classified according to the type of signal they carry and the type of cable they use.

1. Classification by Signal

Signal types include video signals such as analog VGA and digital DVI, keyboard and mouse signals such as USB and PS/2, and audio signals. A combination of these signals can also be transmitted.

2. Classification by Cable

Cable types include twisted pair cables such as Cat5 and Cat6 (CATx cables) and fiber optic cables. CATx cables can extend up to 130 m to 300 m, while fiber optic cables can extend up to 20 km.

There are also KVM extenders, called KVM over IP extenders, which allow access to multiple computers over a network, as well as one-to-one connections. In this case, signals are converted and transmitted over an IP network.

How to Choose a KVM Extender

When choosing a KVM extender, you need to decide on the type of signals and cables you need for your application and environment.

1. Signal Type

Signal types include video signals such as analog VGA and digital DVI, keyboard and mouse signals such as USB and PS/2, and audio signals. Select a product that matches the interface of the keyboard, monitor, and mouse to be connected.

2. Cable Length

Cables include twisted pair cables, such as Cat5 and Cat6 (CATx cables) and fiber optic cables. CATx cables can extend up to 150m to 300m, while some fiber optic cables can extend up to 20km.

3. Connection to Multiple Computers

Some KVM extenders are called KVM over IP extenders, which allow not only one-to-one connection, but also access to multiple computers over a network. In this case, signals are converted and transmitted over an IP network.

4. High Resolution and Security

Consideration should also be given to whether security requirements, such as 4K video and protection of sensitive information, need to be addressed.

What Are FRP Resins?

FRP Resins are fiber reinforced plastics (FRP), which are made by mixing matrix resins such as epoxy resins with reinforcing materials such as glass fibers.

FRP Resins are widely used as lightweight and strong materials for aircraft and other transportation equipment parts, construction materials, sporting goods, and even in the space industry for rocket and satellite parts.

The physical properties of FRP Resins vary depending on the matrix resin and reinforcing material used. Therefore, it is important to select the most suitable FRP Resins for each application.

Uses of FRP Resins

FRP Resins are used in aircraft and other transportation equipment parts, chemical storage tanks, construction materials, sports equipment, and even rocket and satellite parts.

FRP Resins are called by different names depending on the reinforcing material added, and each has different characteristics. FRP Resins containing glass fibers are GFRP.

GFRP has a greater specific strength than metal materials, is a lighter material, and is non-conductive due to the presence of glass.

On the other hand, CFRP, which contains carbon fibers, is stronger and harder than GFRP, but conducts electricity.

However, all FRP Resins share the same properties of being light and strong.

Structure of FRP Resins

Figure 1. Structure of FRP resin

FRP Resins are composed of matrix resins and reinforcing materials. Unsaturated polyester resins, epoxy resins, and vinylester resins are used as matrix resins.

Unsaturated polyester resins have the advantages of easy molding and excellent water resistance. Flame resistance can also be added by adding halogens.

Epoxy resins have excellent acid and alkali resistance and chemical resistance but are difficult to mold. Vinylester resins are easy to mold and have excellent mechanical strength. Bis-A resins are inferior in solvent resistance but superior in acid and alkali resistance, and Novolac resins are inferior in oxidation resistance but superior in solvent and heat resistance.

Types of FRP Resins

Figure 2. Types of FRP resins

Glass fiber, carbon fiber, and aramid fiber are used as reinforcing agents in FRP Resins. GFRP made with glass fibers has a higher specific strength than metal, is non-conductive, and is relatively inexpensive.

On the other hand, CFRP made of carbon fiber is stronger, lighter, harder, and more conductive than GFRP. AFRP made with aramid fibers is lighter and stronger, but less workable.

Because of their different chemical structures, the corrosion resistance of each type of reinforcement varies greatly. The properties of GFRP also change with the grade of glass fiber used.

E-glass, the most commonly used for FRP Resins, contains very little alkali metal and has excellent water resistance, but when in contact with strong acids, components such as Al and Ca leach out, causing cracking.

Carbon fiber, on the other hand, is affected by strong oxidizing chemicals, but can be used in most environments without problems. Aramid fibers have amide bonds that cause hydrolysis when in contact with alkaline chemicals, and they are easily degraded by ultraviolet rays.

Other Information on FRP Resins

Processability of FRP Resins

Figure 3. Processability of FRP resin

Carbon Fiber FRP Resins (CFRP) are formed by infiltrating liquid thermosetting epoxy resin into carbon fibers, cutting out semi-cured sheets, and pressurizing and thermosetting them in an autoclave. However, the above method requires matrix resin to permeate the fibers, making it difficult to apply to thermoplastic resins with high viscosity.

On the other hand, molding methods for CFRP using thermoplastic resin are still being studied, for example, press molding. In this method, carbon fiber containing thermoplastic resin is heated, transported, and pressed in a die, then cooled and cut for processing.

However, this method still has issues, such as the need for a method to cut CFRP with high strength cleanly and without blade wear.

What Are EMCCD Cameras?

EMCCD Cameras are CCD cameras that are capable of detecting faint light using an Electron Multiplying CCD element.

When detecting light with a normal CCD camera, a certain amount of bright light is required. When light is converted into an electrical signal, a certain amount of noise (unwanted information other than light) is added.

Even if faint light is converted into an electrical signal, it is buried in the noise and does not produce an image of sufficient intensity. EMCCD Cameras are able to detect faint light because the CCD sensor has an electronic doubling function when detecting light and converting it into an electrical signal.

Applications of EMCCD Cameras

The main applications for EMCCD Cameras are microscopes and telescopes. The observation area in a microscope is very narrow, and the brightness of the observation area is enhanced by an aperture and a reflector, but the amount of light is insufficient when captured by an ordinary CCD camera.

Therefore, the electrical signals converted from light are buried in noise.

On the other hand, EMCCD Cameras can convert and amplify faint light into electrical signals of sufficient intensity.

EMCCD Cameras are also used to compensate for the low light intensity when photographing faint celestial objects through a telescope.

Principle of EMCCD Cameras

1. CCD Sensor Mechanism

A CCD is a Charge-Coupled Device that converts light into electrical signals. While silver halide film is used in the light receiving part of conventional silver halide cameras (cameras that use film), CCD sensors are used in the light receiving part of many digital cameras.

A CCD sensor consists of small elements (photodiodes) called pixels. The photodiode converts light into an electric charge, and the CCD sensor outputs the charge as an electric current to produce an image.

2. Mechanism of EMCCD

The electrical signals are affected by noise when the electric current is applied, and therefore, with weak light, the electrical signals are buried in the noise and an appropriate image cannot be obtained. Therefore, the EMCCD sensor doubles the electric charge converted from light to a level unaffected by noise.

By doubling the charge, the electrical signal is also doubled, so the output image is sharper and clearer. In this way, EMCCD Cameras can be used in microscopes, telescopes, and other applications that require the detection of faint light to obtain images with sufficient shading to be of practical use.

Structure of EMCCD Cameras

1. CCD Sensor Part

Potential wells are created by applying different voltages to electrodes on the surface of the silicon substrate of the CCD sensor. When light is received by the CCD sensor unit, a charge is generated due to the photoelectric effect.

After the charge is captured in the potential well, it is digitized by an AC converter in a normal CCD. On the other hand, in an EMCCD, the charge is transported to the gain register for charge doubling before digitization.

2. Gain Register

The gain register is a mechanism that doubles the charge sent from the CCD sensor section. It makes use of the phenomenon (impact ionization phenomenon) in which a high electric field is applied during electron transfer to create a new electron-hole pair in a high-energy state.

Other Information on EMCCD Cameras

Noise Factors

EMCCD noise is classified into the following four categories, each of which requires countermeasures:

1. Fixed Pattern Noise

This is noise resulting from variations in the sensitivity of each pixel in the CCD sensor.

2. Shot Noise

This is noise that depends on the number of photons incident on the CCD sensor. As the number of photons increases, shot noise also increases.

3. Dark Shot Noise

The current generated in the CCD sensor in the absence of photon input is called dark current. Dark shot noise is noise caused by dark current, and dark shot can be reduced by reducing dark current.

4. Readout Noise

Readout noise is a noise that originates from the hardware that makes up the camera, including the CCD sensor.

What Are CO2 Monitors?

CO2 Monitors are devices that continuously measure CO2 concentration.

Among devices used for medical purposes to measure CO2 concentration in exhaled breath, those that are portable and display CO2 in real time are often referred to as CO2 Monitors.

The display screen is generally digital with a 7-segment display, and it is recommended that the device be installed in a location that is not easily affected by human exhalation or exhaust gases. Since the atmospheric CO2 concentration is about 0.4%, ppm is used as the unit in most cases.

Uses of CO2 Monitors

CO2 Monitors are widely available on the market and are used in a wide range of applications from offices to agriculture.

• Checking ventilation conditions in offices and conference rooms where many people gather
• Confirmation of CO2 concentration for plants in plastic greenhouses
• Confirmation of CO2 concentration in densely populated areas such as retail stores and restaurants
• Confirmation of ventilation conditions in home rooms
• Analysis of exhaust gas from boilers and automobiles

Insufficient ventilation can cause headaches and other adverse effects, so measuring CO2 concentration is often used as a guide. They need to be supplied with CO2 regularly by carbon dioxide gas.

Principles of CO2 Monitors

Widely used CO2 Monitors are NDIR (Non-Dispersive Infrared Radiation Concentration) type, taking advantage of the fact that CO2 absorbs infrared radiation of its own frequency and does not interfere with N2 and O2, the main components in the atmosphere. The NDIR type has become the mainstream because it has a simpler structure and can be made smaller than other measuring devices.

In the case of the NDIR type, the measuring instrument mainly consists of a light source, a sample cell, an infrared detector, and an indicator. The light source emits infrared light with a wavelength that CO2 absorbs, and irradiates it to the infrared detector via the sample cell. When air containing CO2 flows into the sample cell, infrared rays are absorbed in a form that corresponds to the CO2 concentration. It then converts and outputs to CO2 concentration according to the amount of infrared absorption.

N2 and O2, which are the main components of the air, do not absorb infrared rays, so selective detection is possible, but water vapor and CO absorb infrared rays of the same wavelength, causing interference in the measurement. a light source, it is not suitable for measurement of dirty air such as flue gas.

Types of CO2 Monitors

There are several types of NDIR CO2 Monitors, depending on the number and type of light sources.

1. Single-Beam Type

Single-beam CO2 Monitors have only one light source. Since there is no light source to compare it with, it outputs more CO2 concentration when the light emission is weakened due to light source deterioration over time or dust volume. However, it has the advantage of being inexpensive to manufacture due to its simple structure.

2. Two-Light-Source System

The two-beam method uses two light sources and compares both to perform correction. Compared to the single-beam method, this method can compensate for light source deterioration over time, enabling accurate data to be measured. However, it has the disadvantage of requiring two light sources, which increases the number of parts and increases the risk of failure.

3. Double-Beam Type

The double-beam method uses infrared rays of two wavelengths to measure CO2.

By comparing the two wavelengths, the light source degradation over time can be compensated for, enabling accurate CO2 measurement.

This method has fewer components than the two-light-source method and can measure CO2 concentration more accurately than the single-beam method.

Other Information on CO2 Monitors

CO2 Monitors Other Than NDIR

Solid electrolyte CO2 Monitors other than NDIR are available, which use the chemical equilibrium relationship between CO2 and Na2CO3 to measure the electromotive force generated by the increase or decrease of sodium ions in the solid electrolyte, and convert it to CO2 concentration.

However, while it is less susceptible to interference from other components, its disadvantage is that it is affected by temperature and humidity.