Xenarc 7" 16:9 LCD resolution
Xenarc says that this little LCD monitor can do something like 1280 x 7XX but a closer inspection shows that the native resolution of the panel is 800 x 480. Not near HDTV but still nearly as good as were going to get unless we use a 17" 16:10 display. If we use a 4:3 high rez monitor half of the vertical resolution is wasted on 16:9 DVD playback images.
The Xenarc is around 450 -499 USD and has it's own built in controller. How well it will adapt to thhis use I don't know but I'm prepared to mount the controller on any side necessary to get the LCD oriented correctly.
I still think this is a good size compromize as higher resolution LCD's of this size might become more available in the next couple of years.
The only possible way to get really good rez and contrast is to shine polarized light through the LCD.
I think this is a better design solution than the brute force one of using a giant light source.
Cheers, Paul
Xenarc says that this little LCD monitor can do something like 1280 x 7XX but a closer inspection shows that the native resolution of the panel is 800 x 480. Not near HDTV but still nearly as good as were going to get unless we use a 17" 16:10 display. If we use a 4:3 high rez monitor half of the vertical resolution is wasted on 16:9 DVD playback images.
The Xenarc is around 450 -499 USD and has it's own built in controller. How well it will adapt to thhis use I don't know but I'm prepared to mount the controller on any side necessary to get the LCD oriented correctly.
I still think this is a good size compromize as higher resolution LCD's of this size might become more available in the next couple of years.
The only possible way to get really good rez and contrast is to shine polarized light through the LCD.
I think this is a better design solution than the brute force one of using a giant light source.
Cheers, Paul
Re: Xenarc 7" 16:9 LCD resolution
First of all, that's absolutely not true at all. You'll lose about 30% of the horizontal resolution with a 3:4 panel cropped down to 16:9. If you have an 800x600 panel, you'll lose maybe 50 pixels or so (if any) on anamorphic DVDs, and you won't lose a thing with a 1024x768 panel.
Don't confuse 16:9 with 2.35:1 "panaramic" widescreen. 2.35:1 films are still encoded at 16:9 and still have black bars on the top and bottom. There is no such thing as 2.35:1 video without letterboxing.
$450 is too much. If it were under $300, then I might consider it a decent deal, provided that the contrast ratio was at LEAST 300:1 and the response time is under 50ms.
As of now, I have yet to see a small widescreen LCD have anything beneficial over a high-res 3:4 screen.
Hezz said:
First of all, that's absolutely not true at all. You'll lose about 30% of the horizontal resolution with a 3:4 panel cropped down to 16:9. If you have an 800x600 panel, you'll lose maybe 50 pixels or so (if any) on anamorphic DVDs, and you won't lose a thing with a 1024x768 panel.
Don't confuse 16:9 with 2.35:1 "panaramic" widescreen. 2.35:1 films are still encoded at 16:9 and still have black bars on the top and bottom. There is no such thing as 2.35:1 video without letterboxing.
$450 is too much. If it were under $300, then I might consider it a decent deal, provided that the contrast ratio was at LEAST 300:1 and the response time is under 50ms.
As of now, I have yet to see a small widescreen LCD have anything beneficial over a high-res 3:4 screen.
Correction. You'll only lose about 26% of the horizontal pixels when viewing 16:9 on a 3:4 display. I think an 800x600 panel will fit the whole thing w/o any pixel loss.
There's also a major concern w/ that design. Unless you using a very weak bulb (which in itself would be a problem) you'll burn a hole through the LCD, as there is not even any breathing room for the lamp, let alone any airflow to cool it.
Honestly, w/ high-contrast XGA 15" moniters at $250 and less, I don't see the practicality of going with a non-fresnel/small panel design anymore. These projects were great 6 months or a year ago, but the lowered cost of LCD moniters (that of course all have built in controllers) make these fresneless projects seem like a bad idea. I'm not trying to be negative 🙂)even though I always shoot people down in all of these 7" widescreen forums). It's just that you get a MUCH better image and you don't have to worry about hotspots or elliptical reflectors. Only disadvantage is you have a bigger box- but that's probably a good thing as far as heat management goes.
If you get your hands on a small LCD (w/ controller) for less than $50, then I'd go for it. Otherwise, I'd either get an Nview Spectrah C (no work involved) or an NEC 1545 (work involved but 3 times better res and contrast). I have the latter, and I watch everything in widescreen with no complaints whatsoever.
There's also a major concern w/ that design. Unless you using a very weak bulb (which in itself would be a problem) you'll burn a hole through the LCD, as there is not even any breathing room for the lamp, let alone any airflow to cool it.
Honestly, w/ high-contrast XGA 15" moniters at $250 and less, I don't see the practicality of going with a non-fresnel/small panel design anymore. These projects were great 6 months or a year ago, but the lowered cost of LCD moniters (that of course all have built in controllers) make these fresneless projects seem like a bad idea. I'm not trying to be negative 🙂)even though I always shoot people down in all of these 7" widescreen forums). It's just that you get a MUCH better image and you don't have to worry about hotspots or elliptical reflectors. Only disadvantage is you have a bigger box- but that's probably a good thing as far as heat management goes.
If you get your hands on a small LCD (w/ controller) for less than $50, then I'd go for it. Otherwise, I'd either get an Nview Spectrah C (no work involved) or an NEC 1545 (work involved but 3 times better res and contrast). I have the latter, and I watch everything in widescreen with no complaints whatsoever.
Response
I did not actually calculate the pixel loss but when I play back widescreen DVD's on my 4:3 monitor the vertical size is a little less than half of the vertical size of the monitor. This is done with PowerDVD. I don't know that I have any anamorphic DVD's or not as I just got into this DVD thing but I havn't noticed any that say anamorphic. Or are they all that way by default?
From what I am hearing you say, you claim that the DVD is just letter boxed 4:3. If this is so how can we gain the lost pixel resolution without expensive and complex electronic manipulation of the image.
What do the 16:9 tv's use to get rid of the black spaces?
PowerDVD supposedly adjusts the picture output of the DVD to best fit within the screen of the monitor regardless of the resolution.
I have to disagree with you regarding the other points.
First, the cooling and lighting are not shown in the picture as it is an incomplete mockup. The re-reflector is slightly apart from the main reflector which lets a small amount of light escape but also lets air escape. Another hole not shown at the base of the reflector passes a mounting post for the light and also has an air gap for forced air circulation.
A smallest possible light source should be used because otherwise much light is lost by taking a path back into the original light source.
My goal is to make the best possible picture not the cheapest.
This same design could work exceptionally well with a high resolution 4:3 LCD panel.
Second, using a large non polarized light source will probably generate more heat in the LCD than this method. This is the method the commercial units use.
The reason I chose this size of aN LCD is because it is the only 16:9 LCD with adequate resolution of a reasonably small size.
The larger the LCD the harder to make the focusing lens.
This method could work without the focusing lenses but would have some reduced light output.
Even the OHP based strategies need to have polarized light if they are to have good color balance and maintain the LCD contrast ratio.
The Xenarc has 300:1 or 400:1 and a reasonaly fast response time. I would welcome any less expensive solutions but havn't found any yet.
Hezz
I did not actually calculate the pixel loss but when I play back widescreen DVD's on my 4:3 monitor the vertical size is a little less than half of the vertical size of the monitor. This is done with PowerDVD. I don't know that I have any anamorphic DVD's or not as I just got into this DVD thing but I havn't noticed any that say anamorphic. Or are they all that way by default?
From what I am hearing you say, you claim that the DVD is just letter boxed 4:3. If this is so how can we gain the lost pixel resolution without expensive and complex electronic manipulation of the image.
What do the 16:9 tv's use to get rid of the black spaces?
PowerDVD supposedly adjusts the picture output of the DVD to best fit within the screen of the monitor regardless of the resolution.
I have to disagree with you regarding the other points.
First, the cooling and lighting are not shown in the picture as it is an incomplete mockup. The re-reflector is slightly apart from the main reflector which lets a small amount of light escape but also lets air escape. Another hole not shown at the base of the reflector passes a mounting post for the light and also has an air gap for forced air circulation.
A smallest possible light source should be used because otherwise much light is lost by taking a path back into the original light source.
My goal is to make the best possible picture not the cheapest.
This same design could work exceptionally well with a high resolution 4:3 LCD panel.
Second, using a large non polarized light source will probably generate more heat in the LCD than this method. This is the method the commercial units use.
The reason I chose this size of aN LCD is because it is the only 16:9 LCD with adequate resolution of a reasonably small size.
The larger the LCD the harder to make the focusing lens.
This method could work without the focusing lenses but would have some reduced light output.
Even the OHP based strategies need to have polarized light if they are to have good color balance and maintain the LCD contrast ratio.
The Xenarc has 300:1 or 400:1 and a reasonaly fast response time. I would welcome any less expensive solutions but havn't found any yet.
Hezz
add on
It was not my intention to make a fresneless design. I plan on using one if necessary to correct for uneven lighting. The columnator should work in conjunction with the light polarizer\recycler to make it more effective and by not wasting light going where it doesn't need to go we can use a smaller and less heat generating light source.
I am very picky about visual quality and though the good images I've seen look pretty good I would like something better. If it ends up being a larger high rez LCD then that will be it.
In theory if done correctly, the projected image should look as good as the original screen except with pixel enlargement and some minor abberations caused by imperfect lenses, etc.
Hezz
It was not my intention to make a fresneless design. I plan on using one if necessary to correct for uneven lighting. The columnator should work in conjunction with the light polarizer\recycler to make it more effective and by not wasting light going where it doesn't need to go we can use a smaller and less heat generating light source.
I am very picky about visual quality and though the good images I've seen look pretty good I would like something better. If it ends up being a larger high rez LCD then that will be it.
In theory if done correctly, the projected image should look as good as the original screen except with pixel enlargement and some minor abberations caused by imperfect lenses, etc.
Hezz
more still
After having reviewed a DVD on my computer screen I feel that you are generally correct. Somehow my memory recalled less vertical use of the 4:3 monitor.
I still feel that this is a good design though it will probably require the use of a fresnel lens close to the LCD to even out the light output better.
I am now leaning towards the 4:3 LCD and building an anamorphic lens to add to the design. This will give me more LCD choices and I will have no loss of pixel resolution.
After having reviewed a DVD on my computer screen I feel that you are generally correct. Somehow my memory recalled less vertical use of the 4:3 monitor.
I still feel that this is a good design though it will probably require the use of a fresnel lens close to the LCD to even out the light output better.
I am now leaning towards the 4:3 LCD and building an anamorphic lens to add to the design. This will give me more LCD choices and I will have no loss of pixel resolution.
Well, I'm not making things up here. As far my opinion on whether that's a worthy project or not, that's up for debate, but I know what I'm talking about when it comes to aspect ratios.
First, the opinion part. If you want a projector with the best possible picture, look at my projector (same as cruser's) or YWH's.
Using a $450 monitor that has a weaker resolution, probably a worse contrast ratio and response time instead of using a $250 NEC 1545 is not a good idea. The NEC has a much better resolution, even if you crop off the top and bottom to make it widescreen.
You must not realize how hot a decent light source gets. Even if you use a 200W Xenon (which you won't unless you live in China), a little hole is not going to even come close to getting the job done. Maybe you've got something in mind, but I'm telling you from experience that it will not work like it is in that drawing. And I'm not sure what your talking about polarized light. You can't re-reflect light like an LCD backlight setup does. The back of an LCD is a precise and contained area, and practically no heat is generated from small CFCL lights. Much different in the case of a light source bright enough to project on a wall (no matter how small of a light you find). LCD's have polarizers on them already, so you don't have to worry about filtering anything. What kind of bulb are you going to use?
Now the fact part. I have experience with my setup and I've read a LOT on this forum about light and optics. However, I'm hardly an expert on that stuff. As far as film and video are concerned, I am an expert, and I get paid to know about this stuff. So if you only generally agree, it's not really a debate- I know what I'm talking about. Like I said, your recolection of a DVD image taking up only half of the screen is because your thinking of a 2.35:1 movie.
1. Understand what anamorphic means. It means that the image is out of proportion at the source. It is "scaled" to widen or squash the picture to make it in proportion. In the case of film, anamorphic lenses are used on the camera and on the projector to achive this. In the case of video, a 16:9 image is squished into a 3:4 format. When viewed on a 16:9 monitor, it is scaled to proper proportion.
2. There are 2 standard aspect ratios for theatrical presentation. The standard aspect ratio is 1.85:1. This is the exact size of a 35mm film frame. This format is generally used for comedies, art films- most movies in general. Then there's anamorphic fim (not to be confused with anamorphic DVDs). An anamorphic lens is used to "squeeze" a VERY wide picture (2.35:1) on to a 35mm print. In the theatre, the projector has a special anamorphic lens to reverse the process and project the proper 2.35:1 ratio. Movies like Lord of the Rings, Titanic, etc., are shot with this aspect ratio.
3. Televisions and computer monitors, as you know are 3:4, while widescreen moniters are 16:9 (about 1.77:1). DVD's are encoded digitally, so they can be presented in different formats. If you choose "widescreen mode" (not letterbox) in your DVD player or DVD player software, you'll be viewing an anamorphic image. It's a 16:9 image. If your watching it on a 3:4 monitor, it will be squished (everyone looks tall and skinny). If you watch on a widescreen monitor, it will look normal.
4. The DVD is always 16:9 at the best resolution. If the movie was shot for a 1.85:1 theatrical presentation, a VERY small portion of the sides are hacked off. If the movie had a 2.35:1 theatrical presentation, there are still black bars on the top and bottom even though your in widescreen mode on a widescreen monitor. If your watching a letterbox 2.35:1 movie on a 3:4 TV, it will only use about half of the horizontal lines, which is what your remembering.
First, the opinion part. If you want a projector with the best possible picture, look at my projector (same as cruser's) or YWH's.
Using a $450 monitor that has a weaker resolution, probably a worse contrast ratio and response time instead of using a $250 NEC 1545 is not a good idea. The NEC has a much better resolution, even if you crop off the top and bottom to make it widescreen.
You must not realize how hot a decent light source gets. Even if you use a 200W Xenon (which you won't unless you live in China), a little hole is not going to even come close to getting the job done. Maybe you've got something in mind, but I'm telling you from experience that it will not work like it is in that drawing. And I'm not sure what your talking about polarized light. You can't re-reflect light like an LCD backlight setup does. The back of an LCD is a precise and contained area, and practically no heat is generated from small CFCL lights. Much different in the case of a light source bright enough to project on a wall (no matter how small of a light you find). LCD's have polarizers on them already, so you don't have to worry about filtering anything. What kind of bulb are you going to use?
Now the fact part. I have experience with my setup and I've read a LOT on this forum about light and optics. However, I'm hardly an expert on that stuff. As far as film and video are concerned, I am an expert, and I get paid to know about this stuff. So if you only generally agree, it's not really a debate- I know what I'm talking about. Like I said, your recolection of a DVD image taking up only half of the screen is because your thinking of a 2.35:1 movie.
1. Understand what anamorphic means. It means that the image is out of proportion at the source. It is "scaled" to widen or squash the picture to make it in proportion. In the case of film, anamorphic lenses are used on the camera and on the projector to achive this. In the case of video, a 16:9 image is squished into a 3:4 format. When viewed on a 16:9 monitor, it is scaled to proper proportion.
2. There are 2 standard aspect ratios for theatrical presentation. The standard aspect ratio is 1.85:1. This is the exact size of a 35mm film frame. This format is generally used for comedies, art films- most movies in general. Then there's anamorphic fim (not to be confused with anamorphic DVDs). An anamorphic lens is used to "squeeze" a VERY wide picture (2.35:1) on to a 35mm print. In the theatre, the projector has a special anamorphic lens to reverse the process and project the proper 2.35:1 ratio. Movies like Lord of the Rings, Titanic, etc., are shot with this aspect ratio.
3. Televisions and computer monitors, as you know are 3:4, while widescreen moniters are 16:9 (about 1.77:1). DVD's are encoded digitally, so they can be presented in different formats. If you choose "widescreen mode" (not letterbox) in your DVD player or DVD player software, you'll be viewing an anamorphic image. It's a 16:9 image. If your watching it on a 3:4 monitor, it will be squished (everyone looks tall and skinny). If you watch on a widescreen monitor, it will look normal.
4. The DVD is always 16:9 at the best resolution. If the movie was shot for a 1.85:1 theatrical presentation, a VERY small portion of the sides are hacked off. If the movie had a 2.35:1 theatrical presentation, there are still black bars on the top and bottom even though your in widescreen mode on a widescreen monitor. If your watching a letterbox 2.35:1 movie on a 3:4 TV, it will only use about half of the horizontal lines, which is what your remembering.
more pictures
Lifter, thanks for your responses. You are much more knowledgable than I regarding the technical aspects of the video formats however there are some physics here that you might not be seeing.
1) Your point is well taken regarding the LCD panel.
2) I have done some research on light pipes and this design does indeed re-reflect (for want of a better term) light in many directions until it can only escape via the columnator. Light which is not reflected out of the parabolic reflector into the columnator is reflected back into the parabolic reflector via the dish shaped reflector. It can take many paths but cannot escape (disregarding ventilation holes) until it finds the columnator opening.
3) I have some ideas for forced air cooling that I hope are sufficient to keep things adequately cooled. The LCD will be further physically seperated from the air in the hot side by a glass plate or combined glass plate and fresnel lense.
4) Right now I'm looking at a small Phillips HMI (halide metal iodine) bulb of about 100-150 watts. They are used for location film lighting equipment and are 5600K temperature. They are also expensive, but this is a no holds barred project (relatively).
Here are some more pictures with the anamorphic lens mount of the projector. I have not redesigned the LCD size yet because I want to be able to visualize the whole design first.
Hezz
Lifter, thanks for your responses. You are much more knowledgable than I regarding the technical aspects of the video formats however there are some physics here that you might not be seeing.
1) Your point is well taken regarding the LCD panel.
2) I have done some research on light pipes and this design does indeed re-reflect (for want of a better term) light in many directions until it can only escape via the columnator. Light which is not reflected out of the parabolic reflector into the columnator is reflected back into the parabolic reflector via the dish shaped reflector. It can take many paths but cannot escape (disregarding ventilation holes) until it finds the columnator opening.
3) I have some ideas for forced air cooling that I hope are sufficient to keep things adequately cooled. The LCD will be further physically seperated from the air in the hot side by a glass plate or combined glass plate and fresnel lense.
4) Right now I'm looking at a small Phillips HMI (halide metal iodine) bulb of about 100-150 watts. They are used for location film lighting equipment and are 5600K temperature. They are also expensive, but this is a no holds barred project (relatively).
Here are some more pictures with the anamorphic lens mount of the projector. I have not redesigned the LCD size yet because I want to be able to visualize the whole design first.
Hezz
Attachments
Gotcha. Like I said, I'm no expert on that stuff, just on the film and video stuff. That's a very interesting project. If you can get a nice output with a 150W bulb, I'd be very impressed.
All I can say is that loss of light is not the end of the world. I have a typical OHP setup with no "cones" containing the light paths, and I'm using a 15" display. Before I made the thing, I was very concerned about losing brightness, etc., but I can assure you that it is not even close to an issue of mine. While my OHP is pretty powerful (3M 9850), it has a switch to lower the output to 7000 lumens. I almost always use this setting and it's still bright enough. I have a halogen lamp in the room, and the image is bright enough to where I can have this lamp on and it still looks very nice.
I guess what I'm saying is that if you used a fresnel and a 15" screen, I don't think you're lumen output will suffer as much as you might think. Like me, your interested in a nice projector- not a cheap one. I myself don't have any use for a giant screen that looks like crap, no matter how cheap it is, and I'm sure you feel the same way.
I've been exploring future designs. I do have issues with fan noise, as well as the amount of heat that builds up in the room when the door and window are closed. I'm also concerned with the cost to replace my bulb ($350 everywhere I've looked).
All I can say is that loss of light is not the end of the world. I have a typical OHP setup with no "cones" containing the light paths, and I'm using a 15" display. Before I made the thing, I was very concerned about losing brightness, etc., but I can assure you that it is not even close to an issue of mine. While my OHP is pretty powerful (3M 9850), it has a switch to lower the output to 7000 lumens. I almost always use this setting and it's still bright enough. I have a halogen lamp in the room, and the image is bright enough to where I can have this lamp on and it still looks very nice.
I guess what I'm saying is that if you used a fresnel and a 15" screen, I don't think you're lumen output will suffer as much as you might think. Like me, your interested in a nice projector- not a cheap one. I myself don't have any use for a giant screen that looks like crap, no matter how cheap it is, and I'm sure you feel the same way.
I've been exploring future designs. I do have issues with fan noise, as well as the amount of heat that builds up in the room when the door and window are closed. I'm also concerned with the cost to replace my bulb ($350 everywhere I've looked).
Oh, I wanted to add to that. Right now, I'm having a minor issue with the ring effect from the fresnel showing up on the screen. This will be easily solved once I get around to it. That aside, my picture looks IDENTICAL to how it looks on the monitor. I have a triplet projection lens, so I'm sure that helps, but I have no complaints. All I want (after I fix my minor problem) is a higher res panel (UXGA or maybe even QXGA). A more efficient bulb a less fan noise would be nice, but that can wait until my current bulb starts to fade. And of course there is no contrast ratio good enough when LCDs are concerned (something you should defnately consider before buying that screen). But I'm a very happy camper. As far a color replication and brightness are concerned, the word perfect almost comes to mind.
This is a very good thread, because in the quest of optimizing, one should end up with a better product.
I enjoyed your discussion on the use of polarizers and would like to learn more about the principles as they would be applied in this application. Can you elaborate on the value and mechanism of incorporating a polarizing film and how it affects the resulting light path and image.
Thanks,
David
I enjoyed your discussion on the use of polarizers and would like to learn more about the principles as they would be applied in this application. Can you elaborate on the value and mechanism of incorporating a polarizing film and how it affects the resulting light path and image.
Thanks,
David
More talk and polarizer issues.
I have ben studying two different engineering textbooks. One on LCD's and the other on imaging optics. At this point I have probably only assimilated 5% of the information but one thing that I have gathered from both textbooks is that because of the way the LCD molecules interact with the light rays coming through the LCD panel, polarized light is necessary to get high performance.
The following JPEG is a scetch of how the polarizer/recycler works.
It works on a similar principle described in the light recycling article that can be found elseware in the link archives of this site but it is a more elegant solution for a projector if somewhat less perfect.
Heres how it works.
1) Light enters the first set of lenses which focus the light towards the next lens system. Some of the light is polarized and some of it is not.
2) The poarized light passes through the beam splitter and goes into the next lens without incident.
3) Light that is not poarized is reflected at a 90 degree angle towards the mirror which then reflects it again to pass through a quarter wave retarder. This light then makes it to the second set of lenses.
4) After this process a large portion of the light is polarized. Enough that a film polarizer can be used to polarize the remaining light nearly completely without losing too much of the total light output.
This method has several advantages over a film only solution:
1) It doesn't waste as much light output.
2) If film polarizors are used soley and the light source is very bright the film will absorb too much light and heat energy and the film will be destroyed and lose effectiveness possibly even destroying the LCD.
Here is the schematic.
Cheers, Hezz
I have ben studying two different engineering textbooks. One on LCD's and the other on imaging optics. At this point I have probably only assimilated 5% of the information but one thing that I have gathered from both textbooks is that because of the way the LCD molecules interact with the light rays coming through the LCD panel, polarized light is necessary to get high performance.
The following JPEG is a scetch of how the polarizer/recycler works.
It works on a similar principle described in the light recycling article that can be found elseware in the link archives of this site but it is a more elegant solution for a projector if somewhat less perfect.
Heres how it works.
1) Light enters the first set of lenses which focus the light towards the next lens system. Some of the light is polarized and some of it is not.
2) The poarized light passes through the beam splitter and goes into the next lens without incident.
3) Light that is not poarized is reflected at a 90 degree angle towards the mirror which then reflects it again to pass through a quarter wave retarder. This light then makes it to the second set of lenses.
4) After this process a large portion of the light is polarized. Enough that a film polarizer can be used to polarize the remaining light nearly completely without losing too much of the total light output.
This method has several advantages over a film only solution:
1) It doesn't waste as much light output.
2) If film polarizors are used soley and the light source is very bright the film will absorb too much light and heat energy and the film will be destroyed and lose effectiveness possibly even destroying the LCD.
Here is the schematic.
Cheers, Hezz
Attachments
more on HMI bulbs
Lifter, I guess for me the heating issue was a large thing so I opted to go for a more efficient design. While I was searching for HMI (halide metal iodine) bulbs I found that 100-150 watt Phillips bulbs can be had for about 130-140 dollars and 250 watt ones for 200 dollars. The bulb is a lot smaller than even the 175 watt commercial metal halide bulb. This is not cheap but it is less expensive than your 300 dollar bulb. Are you using the xenon projector bulb.
The smaller bulb size make the reflector work more effectively.
Also these HMI bulbs are the same color as daylight. I don't know if this is ideal in all situations but it should help the LCD render more natural color.
Hezz
Lifter, I guess for me the heating issue was a large thing so I opted to go for a more efficient design. While I was searching for HMI (halide metal iodine) bulbs I found that 100-150 watt Phillips bulbs can be had for about 130-140 dollars and 250 watt ones for 200 dollars. The bulb is a lot smaller than even the 175 watt commercial metal halide bulb. This is not cheap but it is less expensive than your 300 dollar bulb. Are you using the xenon projector bulb.
The smaller bulb size make the reflector work more effectively.
Also these HMI bulbs are the same color as daylight. I don't know if this is ideal in all situations but it should help the LCD render more natural color.
Hezz
Alternative lighting source
Here is the essentially same projector with an easier to build and less expensive lighting source. All components are not shown such as the light base and transformer, etc. Plus size is smaller.
This would be easier to cool with a large fan and light trap.
One large fan on top and lots of ventilation holes on bottom.
A light trap would be necessary to reduce too much reflected light
into the room.
One fresnel would be used prior to the polarizing lenses. Another right before the LCD if needed.
Use inexpensive 250 -400 watt metal halide bulb.
Hezz.
Here is the essentially same projector with an easier to build and less expensive lighting source. All components are not shown such as the light base and transformer, etc. Plus size is smaller.
This would be easier to cool with a large fan and light trap.
One large fan on top and lots of ventilation holes on bottom.
A light trap would be necessary to reduce too much reflected light
into the room.
One fresnel would be used prior to the polarizing lenses. Another right before the LCD if needed.
Use inexpensive 250 -400 watt metal halide bulb.
Hezz.
Attachments
Hezz.
I have been thinking about making a projector using a 7" widescreen too.
As you would know Xenarc have several models in their range, I am considering the 700v. Best price I have found is $269.
The following Url has instructions for dismantling the 700y for use in a project, I would think it would be the same for both models.
http://www.talix.com/
I want to try using one in an old S&K photo enlarger. It has a pair of ventilated glass 9" condenser lenses and can take a negative or Lcd panel up to 7" x 5.5"
The Lcd panel would be external to the heat produced by the lamp.
Jon
I have been thinking about making a projector using a 7" widescreen too.
As you would know Xenarc have several models in their range, I am considering the 700v. Best price I have found is $269.
The following Url has instructions for dismantling the 700y for use in a project, I would think it would be the same for both models.
http://www.talix.com/
I want to try using one in an old S&K photo enlarger. It has a pair of ventilated glass 9" condenser lenses and can take a negative or Lcd panel up to 7" x 5.5"
The Lcd panel would be external to the heat produced by the lamp.
Jon
Xenarc Sources...
Has anyone found a good, cheap source for the Xenarcs? I’m thinking of trying to DIY an LCD projector using a 700Y or YV and possibly later on, building a car PC using a TS or TSV.
Best prices I’ve found so far are as follows: $240 for a 700V, $409 for a 700Y, $449 for a 700YV, $499 for a 700TS and $539 for a 700TSV. All but the 700V (SpySupply007.com) are from OneHitWonders.com and include US shipping. Let me know if your sources are cheaper.
I'd also like to attach a PC to the projector, but I'm not completely sure the $169 differential is worth the native VGA connection. If I wanted an S-Video input back, I'd have to buy the YV or a VGA/S-Video adapter.
By the way -- did anyone know that the original use for this LCD panel was in the old Toshiba Libretto 100/110 palmtop computer? Exact same size and resolution anyway, probably an improvement in contrast and brightness among other things. At that time, Sharp and Samsung made the LCD's -- at the current price points, I doubt Sharp still makes them.
Has anyone found a good, cheap source for the Xenarcs? I’m thinking of trying to DIY an LCD projector using a 700Y or YV and possibly later on, building a car PC using a TS or TSV.
Best prices I’ve found so far are as follows: $240 for a 700V, $409 for a 700Y, $449 for a 700YV, $499 for a 700TS and $539 for a 700TSV. All but the 700V (SpySupply007.com) are from OneHitWonders.com and include US shipping. Let me know if your sources are cheaper.
I'd also like to attach a PC to the projector, but I'm not completely sure the $169 differential is worth the native VGA connection. If I wanted an S-Video input back, I'd have to buy the YV or a VGA/S-Video adapter.
By the way -- did anyone know that the original use for this LCD panel was in the old Toshiba Libretto 100/110 palmtop computer? Exact same size and resolution anyway, probably an improvement in contrast and brightness among other things. At that time, Sharp and Samsung made the LCD's -- at the current price points, I doubt Sharp still makes them.
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