I want to share my newest build: A DIY "real 4k" Beamer.
Here, the 4k means "3840x2160" resolution (called 2160p) upto 60Hz.
Why did I make this little 4k beamer?
SO? I've started this little project.
To save your money, I've done many experiments (tests) instead of you guys.
You can make this 4k beamer rather easily using my AutoCAD drawing files and this instruction.
I hope this instruction may be helpful to someone wants to have a 4k beamer.
It's been around one year since I had a plan to make a 4k beamer.
At first time, I tried to use 15.4 inch 4k LCD as there are several taobao sellers selling 4k boards to drive the LCDs.
However, there are many obstacles in the usage of 15.4" LCDs.
Finally, I could get a 10.1" 4k LCD with a proper driving board.
I tried to build my 4k beamer with the LCD, and tested many lenses.
Luckly, the painful experiments were worthy to make this so-satisfactory 4k beamer.
Let me review the final material sources:
Projection lens : F260 (from taobao), around 178 yuan.
Condenser lens : square-round shape condenser (from aliexpress), 26$
LED light engine and proper constant current driver : (from taobao), around 1000 yuan. You must talk to the seller that you want to buy a 200 watt LED (engraved SSD-90. it is not SSD-90 actually, but modified version) with a CC driver. He can speak understandable English. Tell him that bumhee34 introduced him to you.
Update on LED : this seller will make 300watt LED soon, I do not know whether to try. You may try if you are interested.
Heatpipe for LED cooling : you have many choices. anyway I bought it from taobao, 100yuan. It is temporarily out of stock, but you can buy similar things. Search @ aliexpress.com.
Power supply for LED : 240W SMPS from aliexpress, 17.10$
Power supply for fan and LCD driver : 60W SMPS from aliexpress, 6.30$
LCD and LCD board : 10.1" 4k LCD [model no. : TVTV101QUM-N00], contact Daniel Lee from APTus. The total price was around 250$ excluding shipping cost. I was told that they are not willing to produce more boards as there are not enough demands. But I think they will produce it again if many guys try to make contact with Daniel Lee. Tell him that Bumhee Cho introduced him to you.
Update on boards : the company seems to produce the board again.
HDCP 2.2 bypass tool : this is an important part. If you want to enjoy 4k contents, then you should bypass HDCP 2.2 compliant. There are many UHD TVs but non-HDCP 2.2 compliant. Luckly, there are tools for this kind of TVs to bypass HDCP 2.2 compliant. Some HDMI splitter or some bypass tools will work. In my case, I bought HDFury Integral. It is little bit over-priced, but looks cool and sturdy. And the integral is confirmed to work with my board and Shield TV very well.
You may want this : Shield TV, to enjoy Netflix in 4k (Ultra HD), I bought it.
ETC : Buy minor things depending on your taste. AND prepare your fancy hands.
It is so obvious that this DIY beamer has pros and cons as follows:
Now, you can decide whether to make this or not!
Let me start!
You can skip this step and the next step as I give you the final version of drawings and materials.
I just want to share how I found out the final material combinations.
This step was so painful as I did so many tests with so many lenses.
As the optics is not perfect, the only way to find out best material combination and proper distances between materials is try & error.
This step took me several weeks. Place materials, check the image quality, record...
If new stuffs came, I did the same procedure to find out the best.
I used a linear motion guide to place the positions of the LCD and the fresnel lens easily.
During test, I've found out some useful(?) infos as follows:
Normally, fine grooves on fresnel lens will give you sharper image quality.
The finest groove pitch I could get was 0.1mm. I also test 0.18mm groove pitch from several different sellers, and 0.3mm pitch from three different sellers.
What I found out is that, every 0.18mm groove pitched fresnel lenses have the same defect at the same positions. I suspect the lens mold itself has some defects. I could conclude that every 0.18mm groove pitched ones from taobao are identical and not good. If you use it, you will see dark regions are projected on the screen (see the pic.)
What about 0.1mm pitched one? The seller said it was 0.1mm pitched, but I suspect that it is the same with 0.18mm...the same defect at the same pos., so not useful.
Luckly, 0.3mm pitched ones from fresnelfactory and aliexpress are clean and defects are not visible. These two are the best choices. I haven't tested 0.3mm pitched from optolife.com, you may try if you are interested in it.
When considering LED light, just remember two things; small light emitting area and high power rate
Smaller emitting area will give you sharper images as it becomes more similar to a point source which is ideal. Otherwise, you will end up with blurry edges. The conventional DIY LED light engines has quite large emitting area. If you are stick to it, you cannot make perfect focus forever. It works ok only when you make FHD or less-resolutioned beamers.
High power rate will obviously will give you more bright image. As the conventional LCD is quite dark, you should have enough light power to penetrate much of light as much as possible. Meanwhile, you will burn up your LCD unless you do cool down LCD properly.
Considering above factors, I've tested several LEDs.
First, I tested CBT-140 (from Luminus) which has the smallest emitting area in the market (used in my 2k beamer). However, the power is rated at only around 100 watt, so the brightness is not enough though the image was very sharp.
Second, I switched to 200 watt LED which has no brand, made by the taobao seller I mentioned. It gives enough brightness under dark environment, but I wanted it to have smaller emitting area for sharper images.
Luckly, the taobao seller told me that he could make 200 watt LED, but smaller emitting area than the second one. As shown in the pic, the emitting area is quite comparable to CBT-140. The brightness is satisfactory and the image quality is also satisfactory. SSD-90 is engraved on the LED base, but it is not SSD-90. It is the modified version of SSD-90, I guess.
You may be curious why I used the rectangular-shaped condenser lens.
In the conventional-DIY-beamer way, an aspherical condenser lens is used. Yeah, I tried F78 condenser lens which is commonly used in 7" LCD with F140 back fresnel lens. The lens can be also used with the comination of 10.1" (but 16:10 ratio) with F140 back fresnel lens.
In short, I could not use the combination; F78 condenser lens / F140 back fresnel lens, because the LED light does not fully cover the active area of the 4k LCD. In addition, I could not find 0.3mm (or less) pitched F140 fresnel lens, so the image quality was not good.
That's why I moved to the rectangular-shaped condenser lens. This condenser lens concentrates more light onto the LCD, but the light passage and the focal length are not given analytically.
So? I should find out the best optics positions by many many experiments. If too close to the back fresnel lens, you will see yellowich edges. If too far, you will see bluewish edges. At certain points, the brightness is quite uneven.
This little devil made me stay many nights through several weeks. The final lens positions are quite far from our DIY-beamer knowledges. Anyway, do not worry, just use my drawings.
I just want to give you my experience on the lenses and LCD spacings.
If the LCD is too close to the back fresnel lens, then the grooves will be projected on the screen.
If the LCD is far from the front fresnel lens, the image becomes blurry especially at edges. However, if too close, then discontinous-like images are projected on the screen due to the grooves on the front fresnel lens.
In the mean time, the projection lens quality is important. By rule of thumb, the focal length of projection lens is chosen in the range about +20mm of the front fresnel lens. So, in this case, F240 would be good. However, that is not the only factor to be considered, Field of view (FOV) is another dominant factor in the image quality. Testing many projection lenses, I found out that F260 gives me the best result among them.
Yes, many variables exist. That's why I did many tests.
Long preview (test) is over.
Let's get to the real work now.
To design the housing (case is more correct term?), I must have measured dimensions of all materials. Usually I make mistakes in this step. To save my arcryl (it is also money!!), I double checked, no maybe tripple checked.
To make it fancy, I made Pikcachu by SCAN mode (you can engrave it easily using laser machine).
Anyway, every 2.5pi holes are the points to make M3 holes. Every parts will be held by M3 (headless) bolts.
Ah! There is an exception. The legs are made by M8 headless bolts and "다보" (do not know English term), and you can change them depending on your taste.
After making every bolt tap, you must glue the housing parts. Assemble them temporarily by taping, and glue them by "chloroform". Due to capillarity, the chloroform soak into the joint edges.
This step can be done easily.
WHY? The LCD is quite fragile.
As we are making a beamer, we do not need the backlight unit (BLU) of the LCD. The basic procedure is to be careful. That's it.
Then, place this part in a safe place. Prevent dust from it.
You can ask the seller to cut the fresnel lens in a specific size.
Or, you can cut it by a laser machine or by a arcryl knife.
Anyway, after cut it into the specific size (in my drawing, 260mm x 155mm), Simply attach it on the fresnel lens holder. Please use temporary holding zig to place it in the right position.
This step is rather easy and straight forward.
The LCD and the fresnel lenses will be held by the arcryl holder given in the pic. You can easily assemble and glue them.
To cool down the LCD all the time, 4020 cooling fans will be attached on the sides of the holder above.
This part is not necessary, but it was important part for me.
Yeah, I made Pikcahu and red on the side of my projector. Pixel arts inspired me.
Nothing special, prepare 6 colors, attach it. Just do it. It takes time.
I love my design. Do you?
Following procedures are rather straight forward. Please refer to the pictures.
Almost done. Place everything in the right position, and do wiring.
After everything is done, you should clean up every thing.
BTW, as the LCD driving board does not support HDCP 2.2, we should use a bypass tool.
In my case, I bought HDFury integral, but other cheap HDMI splitters may also work.
I do not know exactly, but HDMI splitters usually destroy HDCP 2.2 compliant.
Anyway, my setup works perfect on Shield tv.
See the final step.
As my cell phone camera is not good, I tried to take the pictures of a PDF file to show you the image qualities.
You can see the image qualities at every position. I should mention that I didn't place my beamer in the right position when testing. Still the quality is super amazing.
As I mentioned, the weakest point is the brightness. Please refer to the pic when the light is turned on. It is not visible. However, it is very satisfactory under dark environment.
I tried to take videos also though the camera quality is not good (last video is test on google play movies, so it is not 4k). Anyway, it is super satisfactory in reality.
In addition, the LCD driving board provides many setting options, brightness, contrast, gamma, hue, saturation, and so on. So, you can calibrate the color space depending on your choice.
I enjoy Netflix in 4k resolution these days thx to my 4k beamer.
I hope this instruction would be helpful to you.