2. ๏ก INTRODUCTION
๏ก HISTORY
๏ก MAJOR PARTS
๏ก CONSTRUCTION
๏ก WORKING
๏ก ADVANTAGES
๏ก DISADVANTAGES
๏ก APPLICATION
๏ก FUTURE DEVELOPMENT
3. ๏ก Created by FRENCH inventor โJULES DUBOSCHโ in 1870
๏ก First used as cellphane roll over for police work
๏ก Widely used I schools & bussiness in late 1950s and early
1960s
๏ก A major manufacture in early period was the โ3Mโ company
๏ก But in 1953 โBUHL INDUSTRIESโ became the leading
contributor
๏ก Very popular in 1990s as they were in almost every school in
U.K.
๏ก During world war 2 as a tool to train groups of survicemen.
4. ๏ก Also called as โVIEWGRAPHโ
๏ก Basic but very reliable tool used to display images or
written material onto a wall or screen.
๏ก F0r audience and presenter can see properly.
๏ก Consist of a large box containing a cooling fan &
lamp, with a long arm extended above it.
5. ๏ก Lamp and Reflector- (with condensor)
๏ก Blower-(cooling Fan)
๏ก Base Mirror- change the angle of the light
๏ก Projection Stage- consist fresnel lens for magnifying
& focusing image upword.
๏ก Upper Section- 1. Focusing knob 2. mirror
6.
7.
8.
9. ๏ก With the help of focusing lens project light from an
illuminated slide onto a projection screen where real
image is formed.
๏ก Depend upon size of transparencies used.
๏ก Includes a mirror just after and before the focusing
lens to fold optical system towards the horizontal.
๏ก At the base the high intensity bulb with reflector is
present which must be fan cooled.
๏ก Condenser is most important part ,which is coollect
all the light and concentrate on the fresnel lens.
10. ๏ก On the fresnel lens the
transparencies is placed.
๏ก also includes manual
focusing mechanism which
raise or lower the position
of the focusing lens.
12. ๏ก Heat and Noise- fan create noise to dissipating heat
created by the incandescend lamp
๏ก Bulky and Heavy Equipment- difficult to carry for
more than short distance .
๏ก Projection Surface- required enough room
๏ก Subject Matter- Display only which is write on the
platform
14. ๏ก Now a days replacement for OHP , document
cameras , computer projection system, and
interactive whiteboard.
๏ก Such system allow the presenter to project video
directly from computer file using software such as
microsoft ppt &libreoffice.