World First! DIY Real 4k (UHD) Beam Projector

The original plan

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.

• Poor driving board : In taobao.com, several sellers sell the boards. To be straight, all the boards are garbages. It uses DP cables, and the length is limited. In addition, it works only with some specific VGAs. Actually, I bought it and tested. No worth to use it.

• Size limitation : if you go for 15.4"... the size will be huge. Also the throwing distance would be limited.

• Lens limitation : the lens combination to be used with 15.4" LCD is limited. Not so many choices.. If you have problems, you will have the problem forever as there are not many alternative materials.

Final Material Sources

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:

• Fresnel lens : both back/front fresnel lenses are F220 and 0.3mm groove pitch. (http://www.fresnelfactory.com/ or from aliexpress), I use fresnel lens from fresnelfactory. Both lens have similar quality.

• 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.

Pros and cons

It is so obvious that this DIY beamer has pros and cons as follows:

Advantage :

• You can enjoy 4k contents. The image quality is really really super nice. I will never go back to any FHD beamers.

• Quite cheaper than commercial 4k beamers! Do the math on the price.

Limitations :

• The main disadvantage of any kind of DIY beamers is poor brightness. This 4k beamer has brightness similar to most of mini beam projectors. BUT, it is super nice under dark environment. My friends said "wow wow whaooo!!". Technically, there are ways to improve brightness using fly eye lens, PBS, and etc (Thx to Ryan Schmit to let me know these tech.), but this will double (or more than that) the cost and time.

• HDR is not supported. As it has a hdmi "2.0" port, not "2.0a", you cannot enjoy HDR contents. I've asked Daniel Lee to check whether the port is upgradable or not. I will update any updated news. BTW, many people say HDR is another new sensation. Hope I could feel it in near future.

Now, you can decide whether to make this or not!

Let me start!

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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:

Notes on fresnel lens quality

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.

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About LED light engine

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.

About condenser lens

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.

Some notes on distances between LCD and fresnel lenses

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.

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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.

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You must be extremely careful in this step.

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.

1. Remove the black tapes along the edges of LCD. Start from the front part. Use a knife and a proper tool.
2. Be slow, do not hurry. Be very careful especially when you remove the tape near the film-like part connecting LCD to the LCD circuit board. Once the film is detached, you never fix it.
3. Apply the same procedure on the backside of the LCD. Be slow and careful.
4. After removing the black tapes, disconnect the BLU cable.
5. Gently detach the LCD circuit board from the back aluminium plate using the proper tool (do not know the term.) as shown in the pic.
6. The last part is more challenging. One of films on the backlight diffuser is attached on the LCD, please detach it very slowly.
7. Then you can hook up the sole LCD. Check the shinny part whether there is a crack or not. If no, you can go further.

Attach LCD to LCD holder

1. Assemble the bottom LCD holder and the temporary holding zig. (please make M3 holes in advance)
2. Attach (is this proper verb?) double-sided tapes as shown in the pic.
3. Dock LCD to the LCD holder.
4. Remove the temporary holding zig, and place paper spacers to prevent over pressure on the LCD by the top LCD holder.
5. Assemble the bottom and top LCD holders together. Do not tighten them so much, or the LCD will be broken. I know cause I did it hahahahahaha()#@$)#@($)!#$.

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.

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Time to attach the LED onto the heatpipe.

1. Mark the positions (on a paper) in where the LED and the condenser lens holder (the lens holder is provided by the seller) will be held by bolts.
2. Disassemble the aluminium block.
3. Make drilling guide points using the proper tool (do not know the term, even in Korean) shown in the pic. Without the guide points, it is difficult to drill at exact positions.
4. Make 2.5pi holes using a drill stand, and make taps into the holes.
5. Remove old thermal grease, and paste new one.
6. Attach the LED and the condenser lens holder, then attach the condenser lens. When dealing with any lenses, use nitrile gloves.
7. The above part is held by the heatpipe holder made by arcryls.

LCD and fresnel lens holder

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.

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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?

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Following procedures are rather straight forward. Please refer to the pictures.

Almost done. Place everything in the right position, and do wiring.

Assemble the followings:

1. Back cooling fans to cool down heatpipe with dust filter x 2
2. A Blower fan on the side to feed fresh air into the box x 1
3. LCD cooling fans on the LCD and fresnel lens holder x 8, if you don't have them, someday the LCD will have black spots.
4. Two push button x2 , one for LED, one for fans and LCD
5. LED monitoring LCD, it watches LED temperature, running time, and brightness. When the temperature reaches 80 degree C, the circuit will be off automatically for safety.
6. 220AC plug x 1 to feed power
7. Fan controller (3 ways) each controlls 1. 2. 3.
8. LCD board (cut off the BLU inverter)
9. 240W power supply to feed LED power
10. 60W power supply to feed LCD and cooling fans
11. LCD driving baord

The wiring stratages are as follows:

• 220AC feeds both 240W & 60W power supplies
• Two main push switches turn on/off 240W and 60W power supplies respectively.
• 240W is connected to the constant current driver (40A in my memory) first, then it is connected to the LED. When dealing with a high current, be sure whether the wire is thick (check awg numbers) enough to stand the high current.
• The constant current driver is also connected into the LED monitoring system.
• 60W is connected to the LCD driving board and 3-ways cooling fan controller
• The cooling fan controller is connected into 1. back cooling fans, 2. LCD cooling fans, and 3. a blower fan.

The cooling strategy is rather simple:

• A side blower fan will feed fresh air, and cool down the constant current driver first.
• The holes on the top covers are the passage for fresh air.
• Heatpipe cooling fans obviously cool down the heatpipe, and suck the fresh air from the blower fan and from the top cover holes.
• LCD cooling fans suck the fresh air from the blower fan and cool down the LCD

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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.

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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.

Acknowledgement

• 4k 프로젝터에 제작에 생각외로 많은 금액이 들어갔는데 저에게 팔 수 있는 중고품들을 기부해주신 최담담님께 감사를 전합니다 ㅎㅎ
• 회사 업무가 끝나고도 같이 실험실에서 도색을 도와준 최강영님께 감사의 뜻을 전합니다..! 치킨 한마리 더 사드리겠습니다..ㅋㅋ
• 회사에 있는 레이저 장비를 사용 허가를 해주신 스탠다드에너지 일동에게 감사의 뜻을 전합니다.
• Thx to Ryan Smit for sharing your knowledge abt a diy beamer, optics and fresh ideas.
• Thx to Jthedd for sharing some key material sources.
• 저를 응원해준 모든 친구들에게 감사합니다.