Sommario
Quick takeaway
1: Not every led display can be made active shutter glasses 3D led display. It need to reach certain requirements
2: The video controller need to support 3D function
3: Need a shutter glasses and corresponding 3D emitter.
4: Need a 3D video content
3D technology brief review:
The reason we can have 3D feel when we look at a 3D item, is because of the visual difference between our left and right eye. Normally the distance of our two eyes (Pupil) is around 8cm. In order to make us see 3D, we have to make our two eyes receive different images, and the difference of the images is to simulate what our eyes actually see. Hence in the 3D video content, in every frame, it has two images, one is for our left eye, and the other is for our right eye. To make this happen, it has two different technologies, passive 3D glasses technology and active glasses technology.
Passive 3D technology:
1:Red and blue glasses
In the early stage of the 3D technology, red and blue glasses takes up most of the market as it is
easy to achieve. Not only it is easy to make a red and blue glasses, it also easier for the video content maker to make 3D content ( mostly movies).
In the red and blue glasses 3D video content, every frame would have red and blue color all over the image.
. by using the red and blue glasses, the red glasses can only pass the red light, hence it will filter the blue light content in the image, so does the blue glasses. Hence our left eye and right eye receive different images, then it create a 3D feel.
Benefits of Red and blue glasses 3D technology
It is easy and cheaper to make not only the 3D glasses but also the video content
Drawbacks of the Red and blue glasses
- The key of the 3D effect performance of the red and blue glasses lies in the glasses’s red and blue color. As there is no standard of the “red” and the “blue”, hence one red&blue glasses for this movie would not have a good visual effect in the next movie
- The displaying device would also be a problem, as different devices, say TV set, computer displays, projectors, they all have their own color gamut, which means the displaying color would have difference and all those difference would make the red & blue glasses 3D a bad user experiences
- Red and Blue color would also make the video content loose many color details
2: Polarized 3D technology
Light has directions, normal light has a direction of 360degree, while after the light passes a polarization glasses, the light remains the direction of same as the polarization glass. 
For example, the original light has direction of 360degree, when it pass through a 90degree polarization glasses, the light’s direction would be remain 90degree, and this light can not pass through other angle polarization glasses.
Hence We can make our glasses left glass with 90 degree polarization glass, and right glass with 180 degree polarization glass. Hence our left eye would only see the light with 90 degree, and right eye would only see the light with 180degree. which also has the visual difference to create the 3D feel.
Benefits of Polarized 3D technology:
- As the polarization glass is transparent,hence it can be used just like normal glasses.
- Have a consistent visual effect watching different movies using the same glasses.
- Main technology used in Movies.
Drawbacks of Polarized 3D technology:
Polarized 3D technology can only be used in
movies theaters, as it need special device to perform different direction light. As when this content is display on TV set or other display, it’s not the light that from the content, but the light from the display which would become full 360 degree light.
Active 3D technology
As the key to make 3D effect is to make our eyes receive different images. Hence what if, in one time only the left eye can see, the next time only the right eye can see. By doing this we can also create a 3D effect. So how do we achieve this?
Normally for displaying content, the frame rate is 60hz, which means the duration of each frame is 1000/60=16.67ms, as now we need to make our left eye and right see different content, hence we can split this frame’s duration into 2 parts. In the 0-8.33ms duration, it displays the left eye’s content, and only for the left eye to see, and in the 8.33-16.67ms duration, it display the right eye’s content, and only for the right eye to see. In this case, actually the frame rate has become 120Hz for one eye, but for two eyes, it is still 60Hz frame rate.
Active shutter glasses 3D technology has 3 main parts, Active shutter glasses, 3D emitter, and a display that support 120Hz frame rate
1: Active shutter glasses
The shutter glasses can black 
out the glass based on the signal of the 3D emitter. For example in the first time only the left glass is transparent and the right glass is black, then only our left eyes can see, in the second time, the left glass would be black and right glass would be transparent, then only the right eye can see.
2: 3D Emitter
The 3D emitter is connected with the displaying device, and synchronizes with the displaying content, hence when the displaying content is for the left eye, the 3D emitter would send signal for the glasses turn on left eye. So does the right eye.
3: Display
The display needs to reach certain specs like frame rate can support 120Hz.
Benefits of the Active shutter glasses 3D technology
- It can be used in any display technology, but the frame rate need to be 120Hz
- Has the best 3D visual effect
- It can show more details, as the left eye and right eye is perceive full details images
Drawbacks of the Active Shutter Glasses 3D technology
- Shutter glasses need battery, need to charge the battery regularly
- 3D emitter has a signal cover range.
- Need special shutter glass 3D content
- More complicated in setting
Due to the theory of the shutter glasses 3D technology, We know that we need the video content to be 120Hz frame rate, like half 60Hz is for left eye, and half 60Hz is for right eye. So do we need to customize the video content to be like that? The answer is no, Actually the video content’s frame rate is 60Hz, but the resolution of the video content is double the resolution of the LED display. Say if the screen’s resolution is 1920*1080, then the video content’s resolution would 3840*1080@60Hz or 1920*2160@60Hz
The Image below is a frame from the sutter glasses 3D video source, you can find it has slight difference in the details of the left and right image
As you see in the picture, the resolution from (0,0)-(1920,1080) is for the left eye, and resolution from (1921,0)-(3840,1080) is for the right eye. When we play the displaying content, our Video processor would ask us to do the setting of 3D function. Then the video processor would configure the video source to be a resolution of 1920*1080@120Hz, then pass to our led display.
Difficulties of Shutter glasses 3D LED display
1: Video processor part
As we know that our video processor output port has a carry ability, now as the frame rate has become 120Hz, which means the data transfered need to be doubled. Since the Ethernet cable has a carry ability too, hence the output port of the video processor need to drop into half its carry ability, around 325000 Pixels. While if it is in 60Hz, 8bit it is carry ability is 650000Pixels. Hence we know that to make a shutter glasses 3D led display the screen layout should be different, as each output port carry less cabinet than before.
Not every video processor has the 3D function, for example,
In Novastar, only MCTRL1600, MCTRL4K, V1260, K16, NovaPro UHD Jr, and H series are supporting 3D function
In colorlight, X20m and X40m support 3D function.
2: Cabinet’s part
Our receiving card also have a carry ability, for example Novastar A10s-n, which has a carry ability of 512*512.
While now for the 3D function, the frame rate has become 120Hz, which means the computing data for the receiving card also would double, and there is a limit of the computing power of the receiving card. Due to different led board design, different quantities of RGB data group are used. For example, Novastar A10s-n, it total has 32 set parallel RGB data group.
Case 1: In this cabinet, it only uses 4 set parallel RGB data groups, how many pixels can this receiving card carry? Will it be able to carry 512*512 pixels? Or only can carry 512*512/32*4 pixels?
Case 2: in this cabinet it uses 16 set parallel RGB data groups, how many pixels can this receiving card carry? Will it be able to carry 512*512 pixels? Or only can carry 512*512/32*16 pixels?
The answer is that the receiving card has a HUB board mode, that when in 3D function, when used different quantities of RGB data group, it has a different carry ability. As you can see the Chart below.
| Receiving Card | Normal Carry ability | 3D function Carry ability |
| A5s Plus | 512×384 | HUB 16 mode: 416*256 HUB 20 mode: 320*256 HUB 24 mode: 384*256 HUB 28 mode: 384*256 HUB 32 mode: 423*256 |
| A8s-n | 384×512 | HUB 16 mode: 384*256 HUB 20 mode: 320*256 HUB 24 mode: 336*256 HUB 28 mode: 336*256 HUB 32 mode: 384*256 |
| A10s plus | 512×512 | HUB 16 mode: 256*512 HUB 20 mode: 200*512 HUB 24 mode: 240*512 HUB 28 mode: 280*512 HUB 32 mode: 320*512 |
For example, if you are using A5s plus receiving card, The normal carry ability is 512*384, if you only used 4 set parallel RGB data groups, then the receiving card is in hub board 16set mode, which means each parallel RGB data groups carry ability is 416*256/16.
And then we know that not every led display can be used as Active Shutter glasses 3D led display
. Like the example below:
Pixel pitch 1.875mm, scan rate 45, cabinet size 600*337.5mm, resolution of 320*180, using Novastar a5s receiving card. has 4 led module per cabinet. led module size 300*168.75, with resolution of 160*90, each led boards use 2 set parallel RGB data group. The whole cabinet use 8 set parallel RGB data group. From the chart we know the hub board is in hub16 mode, that it’s carry ability is 416*256, and total carry ability is 416*256/16*8 = 53248 which is less than 320*180=57600, which means this led display can not used as Active Shutter glasses 3D led display
Pixel pitch 1.875mm, scan rate 30, cabinet size 600*337.5mm, resolution of 320*180, using Novastar a5s plus receiving card. has 4 led module per cabinet. led module size 300*168.75, with resolution of 160*90, each led boards use 3 set parallel RGB data group. The whole cabinet use 12 set parallel RGB data group. From the chart we know the hub board is in hub16 mode, that it’s carry ability is 416*256, and total carry ability is 416*256/16*12 = 79872 which is bigger than 320*180=57600, which means this led display can used as Active Shutter glasses 3D led display
Pixel pitch 1.25mm, scan rate 60, cabinet size 600*337.5mm, resolution of 480*270, using A8s receiving card. Has 8 led module per cabinet, led module size 150*168.75mm, resolution of 120*135, each led boards use 2 set parallel RGB data group. The whole cabinet use 16 set parallel RGB data group. From the chart we know that under 3D function, A8s with 16parallel RGB data group carry ability is 384*256 which is less than 480*270, which means this spec led display can not used as Active Shutter glasses 3D led display.
But after we change it to A10s plus receiving card, A10s’s carry ability is 256*512 which is slightly bigger than 480*270, though theoretically it can work, still not suggest to do that.
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