キラピカマップ

Light is as indispensable to life as air. It not only brightly illuminates ourrooms but is also widely used for power generation and manufacturing
using its energy and for a variety of things that make life comfortable.

This KIRAPIKA Map introduces in an easy-to-understand manner
how characteristics and phenomena of light are used in daily life.

THE LIGHT MAP

Wavelength

X-rays (invisible light)

0.01 nmShort◀ wavelength“X” rays (wavelengths of 0.01-10 nm), the name originallygiven to a mysterious “unknown” light, easily pass throughsoft objects but have difficulty passing through hard objects.

◀ Kirapi

Ultraviolet light (invisible light)

10 nm

X-rays pass through soft skintissue and make it possible toobserve things like the shapes of
hard bone tissue and the status of
the lungs in the body.

Baggage inspection
at airports
X-rays make it possible to check thecontents of baggage and for dangerous
substances and other things that are
not visible from the outside.

Sunscreen creams

Quality inspections at food plants
X-rays make it possible to find metals and plastics mixed in food. In addition,
they are also used to check packed foods for shape defects and quantity.

Sunburns are caused by theultraviolet light contained insunlight. Sunscreen creams
applied to the skin protect it byabsorbing or reflecting ultraviolet
light.

Insect control
Taking advantage of the
behavior of insects, which
tend to gather in ultraviolet
light, it is possible to gather
insects with ultraviolet lightor to prevent them fromgathering with light that does
not contain ultraviolet light,
such as that from LEDs.

Defprodu ective
ct found!

Nature of light
The speed of light is about 300,000 km per second. That
speed makes it possible for light to travel around Earth's
equator 7.5 times per second. The distance light travels in
one year at the speed of light is called a light year. Since
the stars shining in the night sky are very far away, thedistances to them are represented in light years. The lengthof one meter is also determined based on the speed of light,
and it has been established that one meter = the distancethat light travels in a vacuum in 1/299,792,458 of a second.

1.3 seconds
EarthLight takes 1.3 seconds toreach the moon!

▲

The human eye has three types of sensors that sense color andrespond to red, green, and blue light well, and it recognizes manycolors based on the balance of these colors. Birds and insects livein more colorful worlds than humans, as they have four types ofsensors: for red, green, blue, and ultraviolet light. On the other hand,
many animals have eyes with sensors that sense only two colors,
red and blue, so they cannot distinguish between colors as finely ashumans. In other words, living things see different worlds of colors
because the sensors for sensing color vary among them.

VioletIn space,bands of lighare not visi t
because ther ble
e isno air!

Indigo blue
Objects cannot be seen without light

When light from the sun, lighting, or other sources hits objects, the brain recognizes thereflection and scattering of the light, and we are able to see the colors and shapes of theobjects. In a pitch-black room, we cannot see colors, let alone recognize the shapes ofobjects. This is because there is no light reflecting from objects and entering our eyes. If
we turn a flashlight on in a dark room, we can see a band of light. This is because thelight emitted from the flashlight reflects off of invisible particles and dust in the air.

The light that honeybees cansee spans from ultraviolet toyellow light. They can see
flower patterns that are invisible
to humans, and this makes it
possible for them to accurately
determine the locations ofhoney and pollen.

Three primary colors of light (colors of light that are the basis for creating various colors of light)
Other colors of light can be created by mixing three colors of light: red, green, and blue(RGB). Light is white when all three colors are mixed together. Light is yellow when justred and green are mixed together. TVs and computer monitors use these principles tocreate a multitude of colors.

Photos from Flower signals sent to insects:
The world seen throughultraviolet lightby Fumio Yokozawa, 1995.

Three primary colors (colors of ink that are the basis for creating various colors)
Other colors of ink can be made by mixing three colors of ink (pigments): cyan, magenta,
and yellow (CMY). Ink is "black" when all three colors are mixed evenly together. Ink isgreen when yellow and cyan are mixed together. Books, flyers, and this KIRAPIKA Map
are printed using these principles.

Relationships
between lightand objects
When light hits an object,
it is affected in a varietyof ways. These effects on
the light are what allow
us to see the color andshape of the object.

❶ Reflection of light
The phenomenon in which light bounces off the surface
when it hits an object is called reflection. Light that hitsa flat object, like a mirror, is reflected at the same angle.
❷ Refraction of lightSome light is reflected, and the rest of it enters the object andchanges direction. The phenomenon in which light bends atthe boundary of an object at that time is called refraction.

▲

What humans see

What cats see

Photon Valley Center
Creating the future with the infinite possibilities of photonics and electronics technologies

Light bends when it enters and exits
glass, and this changes the direction inwhich it travels. This phenomenon iscalled refraction. Because the lens of amagnifying glass that is thicker in the Central axisof the lens
middle bends light toward the center, it (optical axis)
can make things look bigger when we
look through it and can concentrate
light at one point to create intense light.

https://www.hai.or.jp/pvc/

Refraction
Refraction

We use light to support companies in Shizuoka Prefecture!

Blue

Prof.
Kenjiro Takayanagi

Sunlight

Experiment in theKIRAPIKA LAB!

Waterdroplet

We saw rainbows
formed from sunlightwith handmade spectroscopes!

Prof.
Masatoshi Koshiba

GreenWhen we look at objects, we see the light reflected from them that enters our eyes. Taking the orange color of atangerine as an example, a great deal of the orange colored light from the sun or other light sources is reflected,and the rest of the light is absorbed by the tangerine. The reflected light that reaches our eyes is seen as a color.

Since traveling in a straight line
is a characteristic of light, itwill hit any obstacles in its
path, generating shadows thatlook black (dark) because nolight reaches there. If theobstacles move, the shadows
also move, and this is why ourshadows follow us when werun in the sun.

1. Light from the sun or other light source hits a tangerineG

2. A great deal ofYellow

Cback of theeyes sensethe light

GREENYCyan

3. Sensors at theLight of colors
other thanorangeis absorbed

BLUERM

Magenta❹ Transmission of lightLight that is not absorbed by an object
passes through the object. This phenomenon
is called transmission.

OrangeHow are shadows generated?

BRED

Yellow

Looks
Looks
green
green

Looks
Looks
yellowyellowDetection of neutrinos

Development of blue light-emitting diodes (LEDs)

Born in Hamamatsu in 1899, Prof. Takayanagi
conducted research on mechanisms and technologies
for displaying images from distant places, called the“wireless far-sight method” (television). In 1926, hesucceeded in displaying the character ｲ using amethod involving photography and cathode ray tubes.
Although his research was interrupted by World War II,
he subsequently continued it and completed his
television receiver (current television).

Born in Toyohashi in 1926, Prof. Koshiba built theKamiokande detector at the site of Kamioka Mine in
Gifu Prefecture to observe elementary particles called
neutrinos. The system detects faint light generated
when neutrinos collide with electrons in water, and it
successfully detected neutrinos emitted by a supernova
explosion outside our solar system for the first time in
the world. Prof. Koshiba was awarded the Nobel Prizein Physics in 2002 for this achievement.

Born in Hamamatsu in 1960, Prof. Amano developed
blue LEDs and was awarded the Nobel Prize in Physics
in 2014. LEDs are semiconductors with properties thatcause them to glow when current flows through them,and the development of these blue LEDs led to the birthof the LED lighting widely used around the world.
Because of its long life span and low power
consumption, environmental friendliness is a feature ofLED lighting.

Infrared light (invisible light)❺ Scattering of light
When light hits
objects with small
irregularities on theirsurfaces, particles,
and other things, it isreflected at various
angles. This is called
scattering.

①
Reflection④
Transmission

LightIn the case of
irregularities

Position of thesun during
the daytime

Thin
atmosphericlayers

EarthObserverLightScattering

In the case ofparticles

Thickatmosphericlayers

Position of thesun at sunrise
and sunset

LightLight

Area where light is blocked = shadow

TVs use three primary colors of lightto create 16.7 million colors. When thesurface of the screen is magnified, we
can see that it is made up of three
types of small rectangles that glow
red, green, and blue.

Why isn’t light in bathrooms
too bright!?

What color will the light be
if three colors of light are
mixed together?

Looks
Looks
lightlightblue
blue

In bathrooms, light hits particlesof water vapor
and is diffracted,so it is not toobright.

❻ Interference of light❼ Diffraction of light

Since light has theproperties of waves, lightwaves are strengthened Lightor cancelled out when
they collide with eachother in a phenomenon
called interference.

The phenomenon inwhich light spreads
after it hits a small
object and passes Light
around it or passes
through a narrow holeis called diffraction

Interference

The moon shinesbrightly in the sky,
but it does not emit
light itself. It looks
bright because it
reflects light fromthe sun like a mirror.

Infrared heaters

By detecting the infrared light generated based on
the temperature of the body, it is possible tomeasure the temperature without touching the bodyand to observe the distribution of body temperature.

Infrared light is absorbed by thesurfaces of the body and becomes
heat, and it warms the body up fromwithin via the circulation of blood, etc.

Brix meters

Sweetnessca
determine n bed!

Infrared light specifically associated withsweetness can be used to measure sweetness
without damaging fruit.

The signals sent from remote controls
to TVs use invisible infrared light thatis safe for the eyes.

Motion sensors

Why does the sun shine?
Nuclear fusion at thecore of the sun
generates extremely
high amounts ofenergy in the form ofheat and light. This
reaches Earth in theform of sunlight.

The infrared light emitted byheated pebbles, which heats eventhe interiors of sweet potatoes,
makes it possible to cook delicious
roasted sweet potatoes.

Thermography andclinical thermometers

Remote controls

A human body with a higher temperaturethan its surroundings emits more
infrared light than its surroundings. Thisis used for human body detection, suchas in crime prevention sensors for
detecting the entry of thieves and motion
sensors for air conditioners.

Diffraction

Why does the moon shine?

Why does the color of the sky change? (scattering)
There are layers of air, called the atmosphere, around the earth, andwhen light hits small molecule particles in them, a phenomenon called
scattering occurs in which light is scattered in various directions.
When the position of the sun is high, as seen by the observer, during
the daytime, the entire sky becomes a screen and looks blue because
the blue light is scattered easily. On the other hand, when the positionof the sun is low early in the morning or evening, only red light thatpasses through the thick layers of the atmosphere near the observer
arrives and is scattered, and the sky in the east or west looks red.

Scattering

Since the wavelengths used are invisible,
cameras go unnoticed by people even in the dark.
In addition to being used for crime prevention,
they are also used to observe wild animals.

LightLong
wavelengths ▶

tted
is emi mera!
thgied l by the caInfrardStone-roasted sweet potato
Monitoring cameras and detecte

Light

Blocked1000 µｍ

Invisible light with wavelengths longer than red light is called infrared light(wavelengths of about 780 nm-1000 µm), which means below red light.

RedExperiment in theKIRAPIKA LAB!

that the tangerine isorange in color
Looks
Looks
blueblueLight②
Refraction

Looks
Looks
pinkpink

4. The brain determines

Informationfrom the eyesreachesthe brainorange colored lightis reflected③
Absorption

Looks
Looks
redredLightProf.
Hiroshi Amano

Father of television

780 nmHow do we see the colors of objects? (reflection and absorption)❸ Absorption of light
The phenomenon in which light is absorbed
into an object is called absorption, and theabsorbed light is converted into heat.

Light travels in different directions after passing through a lens (refraction)▲

Rainbows after rain appear
to contain seven colors
because of the refraction
and reflection of sunlight insmall water droplets floatingin the air, which causes thelight to travel in different
directions according to color.
This is called a spectrum

The Photon Valley Center holds events in whichchildren can learn while playing with experiments
using light!

Light our eyes can see actually contains many colors, such as violet, indigo blue, blue, green, yellow, orange, and red. Such light is called visible light (wavelengths of about 380-780 nm).

How we see colors

Theseen a patterns
re different!?

How dorainbows form?

Hamamatsu-related pioneers of photonics technologies

Visible light (light visible to human eyes)

Eyes of honeybees

Eyes of animals
Moon

The color of light can be expressed with words like
red, blue, and green. However, since there are many
more types of color, wavelength numbers can be used
to distinguish colors in detail. Wavelength is expressedin micrometer (µm) or nanometer (nm) units. There isalso light we cannot see but is very useful in our lives.
Light with wavelengths longer than red light is called
infrared light. Light with wavelengths shorter thanviolet light is called ultraviolet light, and light withwavelengths shorter than this is called an X-ray.

Oxidation is promoted around photocatalysts
when they are exposed to ultraviolet light.
This breaks down harmful substances, odors,and other contaminants.

Ultraviolet sterilization

NN GG

Through the ages, natural light has shined down on Earthfrom the Sun, the Moon, and stars. Bacteria thatappeared about 2.5 billion years ago generated oxygenusing energy from sunlight and gave birth to a variety oforganisms. Since the birth of humanity, we have devised
ways of creating light ourselves in order to live more
comfortable and convenient lives. First, we created lightby burning things with fire, and later we created easier
to use and more powerful light with electric bulbs, LEDs,
and other things using electricity. Light is used in a wide
variety of settings according to its characteristics.

Elimination of harmful
substances with photocatalysts

Special invisible inks become
visible when illuminated withultraviolet light from a black light.
This is used for hidden markings
to prevent thecounterfeiting ofpaper money andcredit cards.

Ultraviolet light suppresses theproliferation potential ofmicroorganisms and kills them.
Because it only involves theapplication of light, it is widely usedfor water, food, pharmaceuticalproducts, and other things.

Types of light

380 nmInvisible light with a wavelength shorter than violet light is called ultraviolet light(wavelengths of 10-380 nm), which means beyond violet light.

Black light

X-ray exams in hospitals

Natural light and light created by humans

Let’s play with light in the KIRAPIKA LAB

Heat

Light

Light emitted by living organisms
Heat
Light

Light
HydrogenHeliumHydrogen

Nuclearfusion

Heat
Light

Heat

Heat
Light

In the natural world, light is also
produced by chemical reactions in
the bodies of living organisms,
such as the light emitted byfireflies and jellyfish. Livingorganisms are thought to emit lightto attract prey for food, to scareenemies, to communicate withmates, and for other reasons.

Secret of the mystery of auroras
Auroras are the result of the effects of solar
wind, electrons and protons ejected by
explosions on the surface of the sun thatsurge toward Earth like wind. This solar windgravitates toward Earth's magnet field andstimulates the emission of light from oxygenand nitrogen in the sky above the north andsouth poles. This is an aurora that shines likea curtain in the sky.

We have made every effort to ensure the accuracy of the information presented; however, we do not guarantee the technical rigor of the contents. Issued in May 2022