Q.What
is CCD?
A. It is the abbreviation of
Charge Coupled Device which is a kind of charge coupled device.
The two metal electrodes are arranged with the insulation layer
of 0.1 micro meter on N type semiconductor surface, where the
potential of low area on the semiconductor surface is moved
left or right by controlling the voltage of metal electrodes
and since the accumulated charge can be transmitted sequentially
thereby, it is utilized shift register or memory device. It
is classified into Class I, II and III according to the defect
of CCD pixel.
Q.What
are field and frame?
A. Field : Since TV broadcasting signal (video output)
is commonly scanned by interlace scan, one complete frame
can be composed through even field and odd field of vertical
scan.
Generally the rough image made by one time of scan is called
field.
Frame : Frame is a complete image made by video output of
CCD camera (or TV broadcasting signal)
and one frame is completed by two times of field scanning..
30 frames per second are sent by our TV
standard or CCD camera.
Q. What
is interlace scan?
A. There is a method to configure the frame by the two
times of scanning for making the complete frame. In the first
time, the scanning is done for the odd lines such as 1, 3,
5, 7......, and then in the second time, the scanning is done
for the even lines such as 2, 4, 6, 8, ... lines. So it has
the disadvantage that the outline of the image output is seen
as if it is duplicated.
Q. What
is progressive scan?
A. It is the method to configure one frame by one time
of scanning,, and so called non-interlace scan. It is the
concept contrary to the interlace scan. Generally, the monitor
for PC uses the progressive scan for improving the picture
quality and resolution.
Q. What is the NTSC
standard?
A. It is the image broadcasting standard used in USA,
Japan and Korea in which one screen is made of 525 horizontal
scanning lines. And two times of scanning is done for configuration
of one screen. First, the scanning is done from the top to
the bottom along the odd scanning line and the next along
the even scanning lines. Since this process is made 60 times
a second (60Hz), 30 frames a second (screen) are recorded
and played.
Q. What
is PAL standard?
A. It is the image broadcasting standard used in Europe,
Australia, South Africa, North Korea and China
in which one screen is made of 625 horizontal scanning lines.
PAL uses interlace scanning just as in NTSC broadcasting..
However, the odd line/even line scanning is made 50 times
a second (50Hz), 25 frames can be recorded and played in a
second.
Q. What
is synchronization?
A. It is the matching of the video signal with that of
audio. In other words, when transmitting the data in the multi-digital
systems or in one digital system, it is the matching of the
transmitting speed of video signal and time sequence of audio
signal.
Q. What is PAN/TILT
function?
A. It is the function to move the image to the left and
right, and up and down by remote controller when zooming in
the screen.
Q. What
is USB(Universal Serial Bus)?
A. It is the high speed serial port. For use of USB,
USB port shall be provided and Window 98 or Window 95 OSR2
shall be used. The principle of USB is the same as that of
serial port but it is much faster and convenient than serial
port. It has the transmission speed of 12MB a second which
is enough even when connecting with the most of peripheral
equipments, and it is recognized when using PC or connecting
at the intermediate time and DC power source (up to 5 Volt)
is not necessary because the power is supplied through the
USB terminal from PC. The existing peripheral equipment shall
be connected when the PC power is off, but USB is very convenient
therefor.
Q. Why
projection screen is required during projecting OHP?
A. When projecting the image on the bright color painted
wall, the wall reflects much amount of light.
In case of projection of the same image on the projection
screen, even though the screen is the cheap normal type, it
reflects two times of amount of light. Additionally, since
the light is scattered on the screen surface and it has the
advantage to increase the uniformity of brightness, the screen
is required to reduce the fatigue of eyes when using for a
long time.
Q. What
is the effect of the far infrared rays on the human body?
A. The sun lights are divided into the infra red light,
visible light, ultraviolet ray and X ray according to the
wave length, where the far infra red lights are the lights
having 5.6~1,000 micro meter wave length among the infra red
lights(wave length of 0.76~1,000 micro meter). It has the
strongest radiation energy. The German physician, Bean (the
winner of Nobel physics prize) proved that the far infra red
within 6~14 micro meter has the effect of the "treatment
of warm-heat".
If the infrared lights are radiated into the water molecules
consisting of the cells in body, it vibrates the cells 2,000
times a second microscopically, and the vibrating energy at
the time activates the organization of cells to promote the
blood circulation and strengthen the self-protection of human
body.
Additionally, it produces the heat energy during the process
of minute vibration of cells and promotes the discharge of
the accumulated wastes.
Q. What
is the principle of the ultrasonic cleaning?
A. It is the one using the ultrasonic energy as the cleaning
power, where if the ultrasonic wave is injected into the liquid
such as water, a lot of minute cavity is made so that air
bubble comes out onto the water surface while destroyed or
vibrated, and makes the temporary minute cavitation. The ultrasonic
cleaning is using such "cavitation effect" which
plays the important role such as agitating(by the vibration
of air bubble), chemical and heat reaction (by the destruction
of air bubble).
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