JVC GZMC500US - Everio Camcorder - 1.33 MP Service Manual Download Page 7

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(No.YF100)1-7

Basically, recording media that comply with this CF+(Type II) standard may be used with EVERIO.
However, performance assurance is given to the CF+(Type II) standard with specified Microdrive name by Hitachi, IBM, and other
makes that are OEM supplied by those two companies.
To compare with currently distributed IBM's CF+ standard 2GB and 4GB models, CF standard 340Mb and 1GB models are slow in
transfer speed. As a result, when recording movies, there may be possibilities of failures in recording or replaying as the Microdrives
cannot follow the speed of EVERIO itself. It is remarkably affected when shooting movies in high-quality mode.
In this case, "This card is not for recording video." is displayed. Even with a Microdrive name, without the CF+ standard, performance
assurance cannot be given.
Currently, there are two companies that supply Microdrive CF+ (Type II) small hard disks besides Hitachi and IBM. Their web sites
are shown below for your reference. (There is no performance assurance for their products.)
GS magicstor Inc.http://www.gs-magicstor.com/ It is a Chinese company.
Seagate Technologyhttp://www.seagate.com/It is an American company.

2.3

3CCD System

There are two types in color CCD system: 1CCD system in which
color images are created with one CCD chip, and 3CCD system
which uses three CCD chips to create color images.
In 3CCD system, an image (optical signal) which has been cap-
tured by the lens is separated into three primary colors: Red,
Green, and Blue by color separation prisms before being con-
verted to picture signals by each CCD. As a result, the color pre-
sentation is considerably improved and high resolution is
achieved. However, 3CCD has only been used in professional
video cameras as the color separation prisms are expensive and
a unit of three CCDs leads to large camera size.
JVC's 3CCD system in professional cameras uses dichroic
prisms as color separation prisms. The incident light is separated
by dichroic prisms into each wavelength of RGB, then the light is
received by separate CCDs. The phase in which the Blue wave-
length enters the CCD through the prism is air-gapped to reflect
in the same even phase as the Red and Green wavelengths.
The merits of 3CCD system include: full utilization of high reso-
lution by using corresponding CCD to each wavelength of RGB,
and high color reproducibility and good image quality owing to
optimum image output from each chip.
On the other hand, the demerits of 3CCD system are (as previ-
ously mentioned): difficulties in controlling air-gap due to the
dichroic prism structure, the large camera size due to the compli-
cated light paths, and the high price due to control and produc-
tion costs.

Fig.2-6-1

Light paths of professional 3CCD dichroic prisms

A new type of prism has been developed to introduce small-sized
and lowered cost optical prisms for consumer products while uti-
lizing the high resolution, high color reproducibility, and good pic-
ture quality of 3CCD.

Fig.2-6-2

3CCD for consumer products

As shown in the Fig. 2-6-2 the Blue wavelength is captured in the
CCD as an odd phase. The production management cost can be
reduced by electrically antiphasing the captured signal without
the need for either optical prisms or air-gap.
In an ordinary 3CCD camera, the CCDs are fixed to the color
separation prisms. This requires enough mechanical strength of
the adhesion layer to keep the CCDs stable against vibrations or
shocks. Preventing registration differences caused by the tem-
perature change is also required. The positioning with high accu-
racy is needed as the CCD registration depends on the affixing
accuracy.
Video cameras from other manufacturers use the system in
which the CCDs are directly affixed to the prisms. JVC adopts the
professional camera's proven system in which a wedge glass is
sandwiched between a CCD and a prism.
The Blue channel and the Red channel of a 3CCD camera are
fixed half a pixel horizontally displaced against the Green chan-
nel CCD. When the pixels are displaced, the resolution seems to
be improved. Casting a color separation prism and a CCD as one
unit enables miniaturization of the prisms and the CCDs.
If there are symptoms such as edge coloring as a result of the
above displacement of Green pixels, defects in optical prism it-
self may occur.
In this case, the optical prism unit must be replaced.