Unique
Folded Design of DIY LCD Projector, XGA,
All
inputs, placed near Ceiling, Long Throw,
Ram
Kishan's Projector
Note:-
For Information in
Hindi visit link
http://www.hindimedia.in/content/blogcategory/31/65/
The
results
have now been improved further
by video enhancement using ffdshow converting the video image of XGA i.e. 1024 X
768 into 1776 X 1000. The image quality is now same as that achieved by Mr.
Benchun vide link:-
http://www.lumenlab.com/forums/index.php?s=1495478b749d59a8f3c4638a2b6c23e2&showtopic=5141
We have also
introduced DTH and accordingly the TV reception has improved tremendously. We
have now a 150 inch TV with superb quality images. The screen
shots will be posted in due course of time
Navigation Index to Important Topics on this Page
This page contains 33 numbered paragraphs with titles on
different topics. Following topics of general interest may be instantly
navigated by
clicking on the
titles/titles below:-
(a) Newbies
-
(3) Strategy for Newbies
(b)
Brightness & Focus
-
(8)
Uniformity of brightness from corner to corner
,
(18) Brightness in our Projector,
(15b) Enigma of DIY
builders in respect of brightness and focus
(c) Reflector
-
(9) Suitable design of reflector and placement of
lamp
(d)
Optical Circuit
-
(6)
Optical Circuit - Gap between Lens, Fresnels etc
,
(7)
Mathmatics of Optical Circuit,
(7a) An
Informative Schematic Diagram and Calculation by Gunawan W
(e) Camera Settings
-
(23) Camera settings for screen
shots
(f) Screen
Shots
-
(2) Pictures
shots with bowl reflector - Long throw ,
(24) Picture shots, no reflector - Short Throw
(g)
Materials used & Sources
-
(29a) Materials used by
us and their sources of supply (29b) Import through PayPal against credit card
is quite safe (29c) Overall costs, comparison with commercial projector and time
incurred
(h)
Pictures of Projector
-
Pictures of Projector and
Long Throw Lens
(i)
Ceiling height Placement & Room
- Pictures of Room, Placement of Projector near
Ceiling, Screen wall
(j) Appreciation
by Experts
-
(5)
Appreciation by Experts in DIY Projectors
Basic
parameters of our DIY Projector are excellent
120" image at a long throw distance of 22 feet at 50% default
value of brightness of LCD without removal of antiglare film and without any
glass pre-condenser lens, screen being an ordinary wall painted matt white with
projector light
source of 400W MH metal halide lamp with one fold reflection, the projector placed
near ceiling height on an almirah at corner of the room without causing any clutter
The DIY LCD Projector project is basically assembly of
available components. Its an unique product of its own and for the costs
incurred results in fairly higher value in form of nice screen images and proud
possession of home made distinct electronic gadget.
Optics
are a Science........, Projection an ART!
This page was last updated on 18.10.06 and is
continuously updated depending on the feedback and queries. There is no
commercial interest except sharing of knowledge. This is our own web site and
this page has nothing to do with our core legal business. It is just due to
convenience of instant uploading that we are using part of space of our own web
site. We welcome your feedback at our e-mail
ramkishan@drtsolutions.com
This page
contains notes on Strategy for Newbies, Theory and
Mathematics of Optical
Circuit, Uniformity and Adequacy of Brightness and Focus corner to corner,
Reflector design and practical application, reducing Overall Size of the Projector,
Image Enhancement by the Software Technique,
Maintenance
and Comparison with Commercial Projectors. Easy adjustability and Placement in
the room are the important aspects of our design.
The existing results are excellent even at 50% default
setting of brightness, contrast and RGB levels.
(1) Synopsis
We have built a LCD projector, XGA
120" wide image
with long throw at 22 feet after
studying various web sites and forums. Our approach
is based on first sound scientific analysis and then cost effective
implementation in least time with sole objective of quality screen image.
Input signals are from a HTPC which gives best quality of signals at
lowest costs with flexibility and is used as a SOHO computer. Uniqueness of the projector design is innovative
front opening and adjustability of all components. Due to front opening being in
two parts, all inside components can be adjusted precisely with projection lens in
position and finally the projection lens can also be adjusted to and fro as well
as up and down. We can use either long throw or short throw lens i.e. can get
120" wide image from a screen distance of 11 feet or 22 feet . On account of such uniqueness,
the projector can be placed anywhere and can be easily adjusted for best image.
In our case we have placed the projector (Fig 6)on top of an
almirah kept in corner of a room and the image is projected on the opposite wall
(Fig 7) at a distance of 22 feet just as in a theatre. Hence the room is not cluttered and movement in the room is not affected
at all by presence of the projector box. The image is 120" wide. The design of our projector has been
appreciated by experts like Mr. Alan Staples of diyprojectorcompany.com whose
comments are furnished below after the screen images under the para
'Appreciation by Experts in DIY Projectors'
Still lot of improvements are to be done as and when we get time. Overall, it
has been a highly satisfying fun project with quality nearly as good as any
commercial LCD projector costing 3 to 5 times with added benefits of longer LCD
life, longer bulb life and much cheaper replacement cost of the bulb. We intend
to carry out certain further modifications described hereunder by which the
image quality will further improve
(2)
Pictures shots after addition of reflector and front surface
reflecting mirror:- Marked improvements
have been achieved as compared with pictures shot earlier. The following ten
shots are from currently popular Indian movies 'Black', 'Bunty
and Babli' and 'Paheli' The pictures have been chosen to show the different
colours. The colours are true colours of the movies. The
screen is 120"
wide at a distance of 22 feet using long throw lens and projector at ceiling
height placed on an almirah. In these picture, wife Padma, daughter Rashmi and
grand daughter Mishri are standing before the screen which is
an ordinary wall painted with white matt paint. The
brightness is set at
50% default value of the LCD without removing antiglare film and without any
glass condenser lens just after the bulb and hence it can be increased further
substantially. The
size of the shots and angle differ due to placement of camera. We have
intentionally asked some one to stand before the screen just to show the giant
size of the screen of 120" width. The quality depicted here is much reduced
due to high compression of 1:100 to minimize the web content. The pictures will
further improve after certain modifications like software enhancement described at the end of this web page
to improve the sharpness. Earlier
pictures without these additions are shown at middle of this page.
Below :- Shots from movie 'Black' showing
Abhisekh and Amitabh Bachchan, wife Padma standing before the screen. In 3
pictures, the actor is holding an electric bulb in his hand and hence the colour
of ambient light is that of incandescent lamp, this is obvious as the colour of
gown of my wife remains same in all the four pictures.
Below :- Shots from movie 'Black' showing
Amitabh Bachchan and his eye, wife Padma standing before the screen
Below :- Shots from movie 'Bunti and Babli
showing Aishwarya Rai and Abhishekh Bachchan, wife Padma and daughter Rashmi standing
before the screen
Below :- Shots from movie 'Bunti and Babli
showing Amitabh Bachchan, Rani Mukherjee and Abhishekh Bachchan, wife Padma and daughter Rashmi standing
before the screen
Below :- Shots from movie
Left - 'Bunti and Babli showing
Abhishekh Bachchan, daughter Rashmi standing before the screen,
Right - 'Paheli showing Rani
Mukherjee, wife Padma standing before the screen
Below :- Shots from movie
Left - 'Paheli' showing Shahrukh
Khan, wife Padma standing before the screen,
Right - 'Bunti and Babli showing
Rani Mukherji, daughter Rashmi and grand daughter Mishri standing before the
screen
[ Back to Navigation Index ]
(3) Strategy
for Newbies
There
are two approaches for newbies as under:-
(1)
Buy the entire kit or all components from well established single source like
www.diyprojectorcompany.com or
www.lumenlab.com This is the easiest route
to make a DIY Projector particularly those who do not have sufficient time for
study and experimentation.
(2)
The second approach is to study the contents of various web sites including the
two mentioned above as well contents of their forums along
with other forums like www.diyaudio.com
Massive information is available in these resources. After grasp of the
fundamentals, decide about commencement of the project. With this route
several options and designs are possible. However this is a long route for which
one should have sufficient free time. We have followed this route. Content of
this web page is summary of our knowledge gained through the study,
experience and feedback. This page is, however, mostly confined to our specific design and
relevant informations.
(3)
A practical guide to DIY LCD Projector is given in
http://inventgeek.com/Projects/HomeTheater/HomeTheater.aspx Another
presentation may be seen from
http://www.denguru.com/2004/11/13/supersize_your_tv_for_/index.html which
contains a video clip also. Lot of details are also available at
www.diyprojectorcompany.com
(4)
It is on account of the above mentioned studies that we found that lot of
adjustments are needed for fine tuning with reference to quality of the final
screen image. The design of the projector depends on the budget, size of the
room where the projector is to be placed, actual placement of the projector etc. The look of the enclosure, its finish and
method of fitment of the
components are not so important. Right from the beginning one should concentrate
on the final screen image. We started with an old OHP purchased from a disposal
house, optimized the screen image of the OHP by using a transparency mounted on
a glass plate. Then based on the aperture of the OHP, we selected the size of
the LCD i.e. 13.3" out of a new LCD imported monitor for use with the said OHP.
All adjustments and fine tuning was first done with the transparency. After achieving
satisfactory screen image of the transparency, then the LCD was placed in
position. Initially the enclosure was made by using card board sheets. We found that such
projector placement in the middle of the room was quite awkward and
inconvenient. We, then, imported the long throw lens and placed the projector on the
top of an almirah at corner of the room at a distance of 22 feet from the screen
which was the opposite wall painted with white matt paint. After achieving most
satisfactory results, we prepared the final enclosure with sufficient space
inside for adjustments and fine tuning of all the components.
(5)
If there is any choice of the size of the LCD, one should go for the lowest
possible size. The best option is 7" XGA LCD. It is worth mentioning that even
lumenlab has started manufacturing LCD Projector using 7" LCDs. For lower
size LCD like 7" or 8", size other components like fresnels may be reduced. One
may contact suppliers like 3Dlens.com for the same.
(6)
Our study and experience revealed that the theory of projector is only a guide
but actual building requires lot of adjustments and fine tuning in such a way
that the final screen image is continuously improved. We got excellent results
and still there is sufficient scope for further improvements.
(7)
The study of various forums revealed that lot of persons spent months and years,
spend sufficient money, even spoilt LCDs but could not get good results. On the
other hand, we proceeded cautiously, studied a lot and then took decisions by
always keeping in view the final screen image and continuously improving it.
(8)
Import of components through PayPal against credit card is quite safe. Only
precaution is that the card details should not be disclosed to anyone as there
are lot of fake e-mails for the same.
(9) Overall
it is a fun project with a considerable value return on the costs incurred. A
practical knowledge of electrical, electronics, optics and computers will be
highly useful to obtain desired results in quickest possible time with least
costs.
[ Back to Navigation Index ]
(4) Design
Features of Our Projector
The
conventional optical circuit with distances between the various components is shown in
Fig. 1. The projector (Fig. 2 and 3 below) uses long throw lens
(Fig. 4 ) and is
mounted nearly at ceiling height (Fig. 6) and 22 feet from the wall used as screen
(Fig. 7) for 120" wide
image (Fig. 5, 8, 9, 10, 11 and 12, these are earlier images without
reflector and without proper setting of the camera). It has all inputs including component video, VGA, S video, TV Tuner and
easy keystone correction. It uses 13.3" XGA LCD panel from a monitor brand
"Super" imported through e-bay, Metal Halide lamp 400W,
fresnel lens for OHP (combination of two lenses), 135mm triplet projection lens
and two small exhaust fans etc. Our study of various forums revealed that design
of the enclosure should be such that it should be possible to adjust all the
components easily with precision and hence I made the enclosure with innovative
front opening in two halves for such adjustments and the projection lens is also
mounted with similar adjustments. All the components can be adjusted with fine
precision as well as quickly by watching the final image on the screen. Such
adjustments are essentially needed particularly when one purchases different
parts from various sources and are not matching in themselves. Due to such fine
adjustments, our overall results are excellent in short throw as well as long
throw.
(5)
Appreciation by Experts in DIY Projectors
Several visitors have appreciated our work. Above all we cherish the following
comments of well known expert Mr. Alan Astaples of diyprojectorcompany.com
whose comments vide link
http://www.diyprojectorcompany.com/other/links.htm are reproduced below:-
Ram is a terrific
person and is one of our most enthusiastic builders. Not only that, but his
results images are very good ... if you want to see a very large projection
screen in action, check out his page!
Thanks a lot Mr. Alan for your magnanimity and large heart.
[ Back to Navigation Index ]
(6) Distance between different components in
conventional optical
circuit:- is as under:-
Fig 1 - Schematic diagram of conventional optical
circuit
(1)
A - i.e. between bulb and the fresnel lens - in our case it should be slightly
more than the
effective focal length of the fresnel lens combination so that projection lens
receives the image of the bulb beyond the effective focal length of the
projection lens as the final image of the said bulb is spread over the screen
for uniformity of brightness corner to corner. The placement of the LCD be
adjusted for getting sharp image of the LCD at the screen. The brightness can be
improved by using suitable reflector and position of
bulb in it. Again it needs to be optimized by adjustments.
(2)
D - i.e. between the fresnel lens and projection lens - should be
more than the focal length of the projection lens . It needs to be adjusted till
one gets screen image in proper focus. The corner to corner focus will be better
in smaller size of LCDs. It can also be improved by using iris (diaphragm) in
the projection lens but the brightness will fall. So one has to balance between
brightness and focus.
(3)
B - i.e. between fresnel lens and the lcd - should be between 5 mm to 20 mm.
Actual position will be found by adjustment of the LCD till one gets sharp
screen image. In
our case we have used both the fresnel lenses fused together as in OHP and the lcd is 5 mm away
from the nearby fresnel lens.
Mathematical formulae are available to calculate the exact distances but in
practice, adjustment is essentially needed. As per optical theory, the image
of the bulb formed on the projection lens needs to be spread over on the screen
for uniformity of brightness corner to corner by
placement of the fresnel lens beyond the effective focal length of the projection lens. For a focused
image of the LCD on the screen, the LCD should be situated at more than the effective focal length of the
projection lens. Mathematics of the Optical Circuit is given in next paragraph. On such considerations, we calculated all the distances and
then fine tuned around those distances. In our setup, we need to change the
projection lens only (as in commercial projectors) to make it short throw or
long throw projector. This is possible only when the standard fresnel lens
combination of OHP continues. Our this theory was found to be true in practice
also.
At
present we have used standard fresnel lens for OHP (combination of two lenses). Also we
have now added a semi spherical reflector. The semi spherical reflector is made
out of a bowl which was was got nickel plated by us to improve the reflectivity. Further we intend to mount the bulb vertically
(i.e. axially) in the reflector instead of
horizontally at present. This will minimize the hot spotting at the centre. .
The above are the theoretical and practical considerations and will enable quicker results if one gets all the components
from one source only. In practice most of the DIY entrepreneurs are getting
different components from different sources and hence the said components are not in matched
condition. We also proceeded accordingly and with the experience we found that
the design of the enclosure should be such that fine adjustments should be
possible during actual operation with reference to the quality of the image on
the screen.
We found that most of the existing design features pertain to small
throw of 10 to 12 feet which results in very awkward placement of the projector
quite close to the screen. The commercial projectors provide few additional lens
assemblies for utilization of the projector in different conditions.
To
meet up the above problems we used a long throw lens, introduced a front surface reflecting
mirror before the projection lens (Fig 13 below) and made the enclosure front in two halves so that all
the components can be reached for adjustments during actual operation.
[ Back to Navigation Index ]
(7)
Mathmatics of Optical Circuit
The mathematics of the above mentioned optical
circuit is given by following equation, which we found true in practice and have
used in our setup:-
1/f(F) = 1/ d(BF) + 1/ d(FF)
1/f(P) = 1/ d(LP) + 1/ d(PS)
where the various symbols represent as under:-
f(F) -
effective or combined focal length of fresnels
f(P) - effective or
combined focal length of triplet of projection lens
d(BF) -
distance between centre of centres of bulb and
fresnels
d(FF) -
distance between centre of fresnels to virtual
image of bulb.
d(LP) - distance
between centres of LCD and projection lens
d(PS) - distance
between centres of projection lens and screen
Note:-
(1) The above is highly simplified version and
is intended for calculating various distances approximately. so that we can
position the different components and then fine tune as we have done in
practice. The equations taking into account parameters for plano convex fresnels, individual elements of triplet,
bulb and reflector and spacings between various components will be highly complex and are not needed
from practical angle of DIY community.
(2) The
d(BF) should be more
than the combined focal length of fresnels but less than the focal length of the
first fresnel. The
d(LP)
should be chosen so that it is more than the
focal length of the facing lens of the triplet. Under such parameters, the
fresnels and the projection lens need to be adjusted for focussed image of the
LCD as well as uniform brightness corner to corner. Adjustment of the projection
lens will again be required to focus the LCD finally.
(2) The equation for size of the screen image can also be
derived by applying the above parameters along with the size of the LCD
[ Back to Navigation Index ]
(7a) An
Informative Schematic Diagram and Calculation by Gunawan W vide
link
http://gwidijanto.fcpages.com/projector1lens.xls is reproduced below with
thanks to Mr. Gunawan W. We do not agree with certain comments in this diagram:-
(8)
Uniformity of brightness from corner to corner:-
The DIY LCD Projectors using metal halide lamps, on
account of their inherent design and components particularly large size of LCDs
and large arc length of the metal halide lamp,
may not have uniform lighting on
the screen from corner to corner. The image of the inner bulb containing arc
length appears on the screen. On account of such image, the central portion of
the screen shows more lighting. After use of the reflector and with proper
adjustment of fresnel lens, the central portion spreads, light rays increase and hence lumens
improve at the corners resulting into nearly uniform brightness corner to corner,
as in our case, on
120" image at a distance of 22 feet at 50% default
value of LCD without removal of antiglare film and without any condenser lens
before fresnel, screen being an ordinary wall painted matt white. The bulb may be kept as shown
below at the end of next paragraph and the fresnel should be moved closure to the bulb till one achieves
uniform corner to corner brightness. The brightness is also increased and is
much more sufficient for dark viewing. The results will further improve when we
have vertical placement of bulb in the reflector.
[ Back to Navigation Index ]
(9a)Suitable design of reflector and placement of lamp:-
The biggest constraint in design of suitable reflector for
DIY Projector is large size of the arc length of the most commonly used metal
halide bulb. The bulbs with lower arc lengths are costly and lesser life. In our
project, we chose the MH variety which is the
cheapest and is having longest life but has longest arc length causing adverse
impact on the brightness and focus. The quantity of reflectors needed by the DIY Projector
community is so small that CAD/CAM processes will not be economically feasible.
The desirable shape of the reflector is parboloidal which is not available at
economical prices to work at high temperature. The most convenient and economical design of reflector for DIY LCD
Projectors using metal halide lamps is semi spherical one. For this purpose we
took a
stainless steel bowl of 11" diameter and made suitable openings for the bulb, which may be seen
from the pictures below. The metal halide lamp was so placed that the centre of main bulb
is slightly misplaced to centre of the reflector in the focal surface of the semi sphere.
Off centre placement enhances the life of the bulb by avoiding the concentration
of heat. The said focal surface is
defined as a spherical surface with half the radius as the reflector as shown
below:-
With the above arrangement, we found that the
uniformity and brightness of the light improved considerably. In fact it
resulted into maximum number of rays of light that resulted into maximum lumens. We feel that the size of the
reflector (as in commercial projectors) should be quite sufficient so that the beam of light covers the entire fresnel lens. Further
the size of the fresnel lens should be much bigger than the LCD. We took a
stainless steel bowl of 11" dia. from the kitchen, cut it at two ends and got it nickel plated to improve
the reflectivity. The bulb with reflector were placed inside the OHP metal box
with the exhaust fan fitted from outside. The openings in the bowl improved heat extraction. The
pictures below show the reflector without and with bulb. The bulb and reflector
assembly was placed in the original box of the OHP with the exhaust
fan taken out and fitted from outside. We could have gone for still higher dia. but metal box of the OHP
was not large enough to accommodate the bowl. With this arrangement, the thermal and light circuit were separated. As a
result, the fresnel and LCD was subjected to least heat. The baIlast was also
kept out so that as a whole the projector box had a least heating. This was
necessitated as during peak summer the ambient temperature even rises to 48 to
49 degrees celsius. The fresnel and LCD have a separate cooling fan as they need
to be protected from such heat.
An useful and comprehensive knowledge is available in the
following link on various reflectors and related optical considerations:-
http://www.diyaudio.com/forums/showthread/t-29036.html
(9b) Placement of bulb in vertical (i.e. axial) instead of horizontal position:-
Better beam of light is expected to be produced with better
uniformity of brightness corner to corner. All the lights will come from the
reflector and hot spotting in the center will be avoided. In fact in all the
commercial projectors and in automobiles, the bulbs are mounted vertical (i.e.
axial) in the
reflectors. We shall try this
and then report the results.
[ Back to Navigation Index ]
(10)
In our projector design standard fresnel combination for OHP has been used:-
We have used standard fresnel lens combination of OHP. I
got this lens in the OHP which I purchased from a disposal house. In such lens
combination both the lenses are fused and outside surfaces are smooth and grooves are inside and thus no dust
can accumulate on the grooves. Such lens combination results in lower size of
the enclosure and short throw and long throw lens can be used.
(11)
In folded design, front surface mirror for reflection is a must:-
In folded design like ours, a mirror is used for
reflection. Ordinary mirror which is rear coated gives rise to 3 images
resulting into ghosting. Hence
front surface mirror is a must. With use of such mirror, not only the image
quality improves, the brilliance is also improved. The mirror should be covered
or masked in those areas which are not taking part in reflection. This will
reduce the stray light. The advantages of folded design are smaller enclosure
size and easy front approach for adjustments but disadvantages are more stray
light and dust collection needing frequent cleaning.
(12)
Enclosure, particularly inside must be painted with black matt paint :-
In order to avoid tinge of coloured stray and reflected lights, the
enclosure particularly inside must be painted with matt black paint.
(13a)
The LCD and fresnel lens must have enough ventilation:-
The life of the projector and quality of image with
passage of time is greatly affected if the LCD and the plastic fresnel lens are
least heated. Hence their adequate ventilation is a must even during maximum
temperature period of the year. The plastic lens as well as the glass LCD both
consist of thermal non conducting materials and hence are to be protected from
long exposure to heat. We have separate metal box for the lamp having an
exhaust fan. The fresnels and LCD are being cooled separately by another inlet
fan. With such arrangements, the ventilation is most optimum.
(13b)
After switching off, the bulb need not be cooled:-
The bulb should be allowed to cool in normal way and the
fan should not blow air on it otherwise it will get thermal shock resulting into
explosion even.
(14) Removal
of antiglare film of LCD :-
We have not removed the antiglare film of the LCD as the
brightness is quite sufficient for dark viewing. It is observed that the
sharpness and brightness increases if the antiglare side of the LCD faces the
fresnel. This is obviously due to the fact that the reflection of incidental
light is minimized due to presence of the antiglare film, further due to
presence of antiglare film the light is better guided and hence the brightness
increases. We intend to adopt such placement of LCD in due course of time. .
[ Back to Navigation Index ]
(15a) Reducing
overall size of the projector and quality of focus corner to corner:-
The overall size of the DIY projector can be much reduced.
The key factor is the size of the LCD. Some
persons have built projectors using LCDs of sizes 15" or even 17". The size of the LCDs can be safely be reduced to 7". Use of folded design will further bring
down the size of the projector. Thus DIY projectors using LCDs of 7" size in a folded design will bring down the
overall size of the DIY projector It is worth mentioning that even
lumenlab has started manufacturing LCD Projectors using 7" LCDs. In our case we have used XGA LCD of 13.3".
with one fold reflection. That is why our enclosure is
comparatively of smaller size being 22" X 23" X 25". We have kept enough space inside for making
adjustments. We can reduce it further but it is not needed as
being placed over an almirah where we do not have any space constraint or mounting problems.
In fact the more we reduce the size of the LCD, better will be image quality in
respect of focusing from corner to corner. The commercial projectors have LCDs
even below !". Further the commercial projectors have 12 to 15 elements in the
projection lens as against 3 in DIY projection lens and hence the quality of
image with reference to focus corner to corner is far superior. Another
important factor affecting image sharpness is arc length of the metal halide
lamp. It should be as short as possible but then cost goes up tremendously as in
commercial projectors as well as the life span of the bulb assembly goes down. Use of
condenser lens before the fresnel lens would give better results.
(15b)
Enigma of DIY builders in respect of
brightness and focus:-
The DIY Projectors have their own limitations in respect
of the following components and compromises:-
(a) Light Engine:- The DIY builders can not afford
small arc bulb and matching reflector assemblies. Perfect light engine for the
larger size of LCDs used by them will be enormously costly. This is the first
compromise resulting into built in adverse impact on brightness and focus. The
best trade off is, as we have done, is to use large size of reflector with
proper placement of the bulb and to move the bulb near to fresnel till one
gets the optimum balance between brightness and focus. We arrived at this
conclusion first by theory and then confirmed in practice.
(b) LCD:- The LCDs available to and used by the DIY
builders are inherently not suited to projectors due to great loss of light. The
only options is to use as small as possible.
It is worth mentioning that even lumenlab has started manufacturing LCD
Projector using 7" LCDs. We could get 13.3" XGA LCD monitor
and it served our purpose beautifully as may be seen from the results. Larger
LCDs like 17" require special light engines, fresnels, projection lens, more
power consumption, bigger enclosures and hence much costly project. Ready
availability of such LCDs continue to mislead the newbies as well as those who
continue to struggle to complete their projectors out of such LCDs.
(c) Projection Lens:- The DIY builders can not
afford perfect projection lens. They have to be contented with triplet instead
of lens having 10 to 15 elements as in commercial projectors for different optical corrections and
compensations.
(d) Combined impact of above and intelligent trade off:-
There is multiplier effect of above shortcomings on the brightness and focus. We
must accept these realities and with proper understanding of the theory devise
trade off. Our approach centered round the final screen image by proper
adjustment and fine tuning of different components and in fact right from the
beginning we proceeded accordingly as described in this web page. Our
recommendations are also on the same footing. Hence we did this fun project with
least cost and least time with value of final results being much higher than the
costs incurred.
(16)
Use of VD-Z3 converter for playing component video output of the DVD player:-
I imported VD-Z3 converter to use component video output
of the DVD player. The results are excellent. But mostly I use a desktop
computer for utilizing VGA output which is much better. We use our projector for
playing movies and have no experience of playing games.
(17)
Substantial improvement has now been achieved by image enhancement techniques by
using special softwares:-
We have now used the software route to improve the image
sharpness. The results are fantastic. The new screen shots will be presented in
due course of time. The XGA i.e. 1024 X 768 image has been video-processed to
1776 X 1000. We have followed the method prescribed by Benchun in the following
link:-
http://www.lumenlab.com/forums/index.php?s=1495478b749d59a8f3c4638a2b6c23e2&showtopic=5141
As prescribed, I have used the Zoom Player Professional,
FFDshow video processing software and nero decoder.
Specific
features of our DIY Projector and other relevant aspects
(18)
Brightness in Our Projector:-
Brightness is quite sufficient and uniform from corner to
corner even at the
50% default setting of the LCD without removal of
antiglare film and without any condenser lens before fresnel for image size of 120"
at a distance of 22 feet on an ordinary wall painted matt white.. The contrast and RGB levels are also at
50% We use these settings for dark viewing of the movies. If we enhance the
brightness and contrast level, the image is nicely visible in low lighted
condition. The use of bigger reflector, proper placement of bulb, fresnel lens,
proper position of the LCD, utilization of front surface mirror has resulted in higher brightness. The focus
is nearly uniform with slight blur at the corners which is not noticeable. This can be corrected by use
of proper iris (diaphragm) with the projection lens but then brightness will
fall. As a whole, proper balance can be struck with focus and brightness. Our design of enclosure is quite suited for such
optimization.
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(19) All
inputs:-
Right from beginning we chose the 13.3" XGA LCD monitor
having all inputs such as composite, s-video, VGA, and TV tuner. As may be seen
from the Fig 6 and 7 below, our computer having AMD 2200 chip is placed in the
same room. The VGA output of the computer is connected to its monitor or LCD of
the projector through a logic sharer. With such arrangements, we have full
utilization of the computer for routine work as well as for projector when
needed.
(20) Easy
adjustability:-
The study of various forums revealed to us that all the
components need adjustments with reference to the final image on the screen.
With easy front opening, it becomes very easy to carry out precision adjustments
and fine tuning for most optimum screen image. The bulb replacement, when
needed, also becomes quite easy. If the projector requires moving to another
location, the design helps to fine tune in the altered position. After
optimization of image, one can devise near permanent fixing of the components
for short throw or long throw.
(21)
Maintenance of the projector:-
Periodically once in a month or two dust is to cleaned.
With easy front opening, it is an easy task.
(22) Screen:-
We have used the opposite wall at 22 feet from the ceiling
mounted projector, as screen after painting it with matt white paint. The
expenses are least and there are no such problems of mounting and or sagging
There are no hot spots and viewing angle is quite large. Since the brightness is
quite high, we do not feel need of special screen having higher gains.
(23) Camera
settings for screen shots:- The screen shots were photographed at auto setting of a
digital camera (mounted on a tripod) with sensitivity at 50 ASA, maximum EVA and
proper setting of white balance. The maximum exposure achievable with this
camera was 4 secs. The images were compressed to nearly 1/100th value to serve
as web page insertion. Actually we need higher exposure. Whenever we get the camera
with 'B' position opening, we shall take these photos with different exposure
timings by which we expect better results. If one is getting a grainy image, it
is due to low exposure time. If the colours are different from the original
image, it indicates that the white
balance has not been set properly.
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(24)
Comparison between DIY and Commercial LCD Projectors:-
The cost is nearly 20% of the
equivalent commercial version with added advantages of a very cheap lamp,
much longer lamp life, much longer LCD life due to enough ventilation etc. The
only disadvantage is size. In our case, we have placed it on top of an almirah using the
already vacant space. Hence the projector does not require any special mountings or
space and it does not disturb the space in the room. In respect of brightness,
one should not compare with DLP Projectors as the technology is entirely
different from LCD Projectors. The brightness level of DIY projectors is
comparable with the conventional movie theatres. In case of DIY LCD Projectors, the brightness
level achieved using 400W metal halide bulb is quite sufficient for dark viewing.
As may be seen from the screen shots given in the beginning of this page, we got
good brightness even at 50% default setting of LCD brightness. If one desires
to view the image in lighted environment, the wattage of the bulb may be
increased to 1000W. We feel that as a custom built DIY LCD Projector, one can
achieve much better performance parameters compared with commercial projector
except the size and power consumption.
The brightness and focus is definitely better in commercial projectors
due to superior light engine (but it is very expensive), special lcds (having
maximum transmissivity of light), smaller lcds (obviously needing lower
incidence of light and hence lower size of other components as well as
enclosure) and highly superior projection lens (having elements 10 to 15
compared with 3 in diy, to achieve better focus, least distortion, astigmatism,
spherical and chromatic aberration, various optical compensations etc. but very
expensive)
As
a whole It is a fun filled. useful and creatively satisfying project
resulting into much higher value compared to costs incurred provided one
has time and scientific temper of mind. Such projectors will be highly useful to
educational institutions due to lower initial costs as well as lower running
costs on account of inexpensive bulbs, which are quite high in case of commercial
projectors. For technically competent persons, the custom built DIY projector
will give even superior results compared with a commercial projector for much
cheaper initial price as well as much lower running costs if the size constraint is ignored.
[ Back to Navigation Index ]
Fig 2 - Projector Front View mounted on ceiling height
on an almirah. The lens cover is hanging. The size of the enclosure is 22" X 23"
X 25". It has sufficient inside space for adjustments and hence the size
can be further reduced.
Fig. 3 - Projector Front View
bottom half Open,
lens closed by a cover, upper half can also be opened, inside metal halide lamp kept in a metal box with an
exhaust fan on left. Fresnel and lcd screen mounted horizontally on 4 adjustable
screws, reflecting mirror kept at 45 deg behind the projection lens.
Fig. 4 -
Long Throw Lens Assembly, can be adjusted up and down and to and from
Fig. 5 -
(Earlier picture, long throw)Screen Image 120" inches wide, a shot from a movie
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Fig. 6 - Projector at ceiling height kept
on an almirah, opposite wall at a distance of 22 feet used as screen which is
shown in the picture on right at Fig. 7
Fig. 7 - Screen using opposite wall matt white
painted in the same room
[ Back to Navigation Index ]
Fig. 8 - (Earlier picture, short throw)3D image with Suhani, grand daughter. For
experiencing 3D effect, please use 3D red blue glasses.
Fig. 9 - (Earlier picture, short throw)3D image with Suhani, grand daughter
Fig. 10 - (Earlier picture, long throw)Suhani, grand daughter and Padma,
wife
Fig. 11 - Suhani, Grand daughter
Fig. 12 - (Earlier picture, long throw)Rashmi, daughter; Padma, wife;
and Mishri, grand daughter in
projected picture and Suhani, grand daughter standing in front of the screen.
[ Back to Navigation Index ]
Fig. 13 - (this Fig. is reproduced
with permission from
Mr. Alan Staples of diyprojectorcompany.com and the link to original fig. is
http://www.diyprojectorcompany.com/designs/pico_lcd_panel.htm)(25) Basic Concept in my projector is shown here,
the metal halide lamp is at the bottom compartment in a box. The fresnel lens, lcd
screen, reflecting mirror, exhaust fan and long throw lens are in top
compartment. The ballast and monitor is mounted outside.
(26) Specific
details of our own Projector This project was initiated as our 29" TV
was moved out and one of the rooms fell vacant. While studying alternatives, I
studied diy projector sites, came across
www.tomshardware.com and started building such projector after buying a junk
overhead projector (OHP) from a local disposal shop for Rs. 1400=00 (i.e. $30).
The metal halide lamp 400W
was kept inside the metal enclosure of the OHP. The exhaust fan and the top
glass remained as in OHP. The fresnel lens was taken out and mounted on four
screws. All trials and settings were made using a transparency of
our own photographs. Having
achieved a satisfactory 120" wide image on short throw, we obtained a 13.3" LCD monitor.
Taking out the screen was a challenging task. Finally we could do so after
obtaining a special flat ribbon cable.
LCD screen was placed on top
of the fresnel lens. We got very good results but the projector was
occupying centre of the room at a distance of 10 feet from the wall used as screen
after painting it with white matt paint. Then we
obtained the long throw lens,
a reflecting mirror
was mounted at 45 deg.
long throw lens was placed
in a wooden assembly having adjustments shown in the pictures.
Thus the distance was increased to 22
feet from the screen with the projector placed on an almirah. In the meantime I studied various other sites and accordingly the
unique design of the enclosure was developed. The front opening being in two
parts, all inside components can be adjusted precisely with projection lens in position
and finally the projection lens can also be adjusted to and fro as well as up
and down. With such easy adjustability of all components, one can optimize the
image not only quickly but in any placement of the projector. Now my grandchildren and other
family members, relatives and friends are enjoying the theatre like atmosphere
in the said vacant room..
The projection lens is resting in a tight
fit hole and can be adjusted by moving with hand with slight force. Due to
gravity and friction, it remains in its place.
The 3D pictures (Figs 8 and 9) are shot by
moving the camera axially by taking two shots as if the pictures are seen by
right and left eyes. These two pictures are then merged using special
software. The 3D glasses are available in the market..
The results will improve when we introduce image enhancing techniques like using ffdshow.
This is quite possible to implement
as and when we get time.
Till such we continue to enjoy full fledged movies in
our own theatre named as 'Sona, Mishri, Ginni
Theatre, named after our 3 grand daughters.
This page has been referred to in four
forums viz diyprojectorcompany.com, lumenlab.com, hometheater.com and
diyaudio.com. Any visitor,
if has any query may kindly raise the same in any of these forums against our
threads, the same would be replied there and if necessary the content of this
page would be updated suitably. We are thankful to numerous contributors in the
said three forums, with whose knowledge we could complete the project and will
improve with passage of time to attain the standards set by Mr. Benchun in
lumenlab forum.
[ Back to Navigation Index ]
(27) Our threads in various forums are as under;-
http://www.diyprojectorcompany.com/phpBB2/viewtopic.php?t=1433
http://www.lumenlab.com/forums/index.php?s=21279a8018e3a04599455239a234482d&showtopic=9495
http://www.hometheaterforum.com/htforum/showthread.php?s=&threadid=250799
http://www.diyaudio.com/forums/showthread.php?s=&threadid=71758
(28) Important web resources on DIY Projector are as under:-
http://www.diyprojectorcompany.com/
http://www.lumenlab.com/
http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=20
http://www.denguru.com/2004/11/13/supersize_your_tv_for_/
http://inventgeek.com/Projects/HomeTheater/HomeTheater.aspx
http://digg.com/hardware/DIY_home_projector
http://www.exclusiv-online.com/shop/index.php?main=main&lang=en&up=0 (for materials)
http://www.louisville.edu/~wchall01/diyprojector/overheads.htm
http://www.diytheatre.com/default.htm (for DIY screens)
http://www.avsforum.com/
(for DIY screens)
http://www.allinbox.com/
(French)
http://diypro.net/ (Korean)
http://www.diy-community.de/ (German)
(29a) Materials
used, sources of supply, overall costs and time incurred :-
(1)
Metal box containing lamp. top glass and exhaust fan are from a junk OHP
purchased from local disposal shop,
(2)
LCD XGA 13.3" is from a monitor brand "Super" purchased through ebay, monitor has all inputs
including TV Tuner.
(3)
Flat ribbon cable extension for LCD purchased from
www.lumenlab.com
(4)
Projection lens 135mm 450mm FL (for long throw of 22 feet) was purchased from
www.diyprojectorcompany.com
(5)
Fresnel lens purchased from www.3Dlens.com,
(6)
Metal Halide lamp 400W along with ballast purchased from local electrical market,
(7)
Reflector made out of a bowl which was nickel plated.
(8)
Front Surface
Reflecting mirror 16 inch X 12 inch purchased from
www.lumenlab.com ,
(9) Exhaust fan 4" 220 volt purchased from local market,
(11)
Wooden enclosure made and painted by a local carpenter
(12)
White matt painted wall used as screen
(13)
An existing desktop used as HTPC with AMD chip +2200, the desktop is in regular use and
its monitor and projector's monitor are switched in using a logic sharer.
(29c)
Overall costs, comparison with commercial projector and time incurred:-
The overall cost of the projector built in 2005 was
within Indian Rs. 16,000=00. It could be less if second hand parts are used. The
equivalent quality of commercial projector would have costed between Indian Rs.
1 lac to 1.5 lacs. The biggest advantage is the replacement cost of bulb
assembly which is much less i.e. Indian Rs. 600 as against Rs. 15,000 in case of
commercial projector as well as the life of the bulb assembly which is much more
i.e. 10 years as against 2 years in case of commercial projector. The projector
making consumed about 80 hours spread over a period of 9 months. It was
utilization of free time as and when it was available.
(29b)
Import through PayPal against credit card is quite safe:-
As mentioned above we have imported several components
through PayPal against our credit card and it is quite safe, only precaution is
that one should not disclose the card details to anyone as there are lot of fake
e-mails for the same,
[ Back to Navigation Index ]
(30) Final
conclusion, further improvements achieved and recommendations :-
The results achieved by Mr. Benchun in lumenlab forum are
superb and are the benchmark for the image quality. These can be seen by
clicking the following link:-
http://www.lumenlab.com/forums/index.php?s=1495478b749d59a8f3c4638a2b6c23e2&showtopic=5141
We have now implemented the method prescribed in this
link. The results are fantastic. The new screen shots will be presented in due
course of time. The XGA i.e. 1024 X 768 image has been video-processed to 1776 X
1000. As prescribed, I have used the
Zoom Player Professional, FFDshow video processing software and nero decoder.
The field of DIY LCD Projector is so vast and
becomes complex the moment one starts with few available components. Better
approach will be to buy all the components from one source and then optimize the
final results after understanding various parameters. Sufficient knowledge
resource is available in all the 4 forums mentioned above.
My chances of making second projector are highly remote but if I have to do so I
will adopt the design as given under
My 7 inch Lilliput
below which is having much smaller dimensions, best
quality of image and economical also.
(31) Other
good examples:- Other good examples of
DIY LCD Projectors are contained in the following links:-
My 17” Projector
By Asdasl in diyprojectorcompany.com
And superdaveumo in diyaudio.com
http://www.diyaudio.com/forums/showthread.php?s=&threadid=69975
Following useful links have
been mentioned on the topics below:-
Anti-Glare
http://www.diyaudio.com/forums/show...1724#post781724
Bulb and Ballast
http://www.diyaudio.com/forums/show...&threadid=65296
LCD Disassembly
http://www.diyaudio.com/forums/show...&threadid=65002
Opaque Projector / 18" FL Projection Lens
http://www.diyaudio.com/forums/show...&threadid=64473
My 7 inch Lilliput
By weezbundun in diyprojectorcompany.com
http://www.diyprojectorcompany.com/phpBB2/viewtopic.php?t=1072
The pictures of the projector are contained in the link below:-
http://www.dv-memories.com/Projector/
(32)
Screen - Fundamentals and Analysis
Based on contents in the
following resources, we used the wall opposite projector as screen, painted it
with white matt paint. It resulted into good quality images without any hotspot.
http://www.diyprojectiontv.com/Screen_Guide-72.pdf
http://www.avsforum.com/avs-vb/showthread....threadid=262466
http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=240074
http://www.carada.com/
[ Back to Navigation Index ]
(33)
Special Note:-
This is special page of our own web site. We have
utilized part of our own space due to convenience of instant uploading on 24X7
basis through our desknote computer even using mobile during traveling. Invitation
to visit this page has no relevance or impact on our core business in the field
of law. The DIY entrepreneurs visiting this page are concerned with projector
and are not interested in other pages of this legal web site. Our clients are rich
industrialists who are not interested in DIY Projectors. As may be seen from the
above content, visit to this page does not result in any earnings or sales
promotion of any supplier. Our only motto is to apprise the DIY community about
our knowledge, experience and suggestions for building a DIY LCD Projector. This is just
for information that many experts in the field as well as the newbies have
appreciated our design as well as above content. We are very keen to know the
details of DIY projectors using long throw lens in similar setups like screen
width 120" and distance of 22 feet between the projector and screen. We are open for interactions
through above forums and or direct e-mails to
ramkishan@drtsolutions.com
Mr. Ram Kishan is originally a Telecom
Engineer (1965 batch) and has worked in various industries in the field of
Materials Management, Production Management, Project Management and now manages
the present highly specialized law firm dealing with application of law of torts
and law of damages for the defence of borrowers and guarantors facing recovery
actions from institutional lenders. The above project was done just for fun for
my 3 grand daughters (eldest born 1998) who now enjoy weekend movies alongwith
our relatives and friends. The visitors of this site may offer their comments or
queries in one of the 4 forums mentioned above. By the way I have not come
across any body who has made such projector in India. If there is one, I would
like to exchange notes with him and till such time, ours will be the first
projector so made in India. The visitor's are free to use content of this web
page and refer to as Ram Kishan's Projector.
This page was first launched on 15.01.06 with few sentences and without
any picture but now has grown to its present shape due to constant interactions
in 4 forums. Cyber world is a new society from which we have gained above and as
a gratitude desire to return as much as we can.
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