Eachine EV100 component analysis: Display module supplier and technical data

By | September 20, 2017

It seems like I have tracked down the manufacturer of the display that is built into the Eachine EV100 goggle. I was doing some google picture search in order to identify the viewfinder. On accident I stumbled across this banggood viewfinder offer for a similar product. Have a look at the first picture, do you notice the purple paper sticker on the flex cable? That banggood offer looks quite similar to the one found on the EV100 module:

Banggood viewfinder (Screenshot)

EV100 viewfinder

To me the sticker and the flex cable look too similar to be a coincidence. The module is clearly not the same but at least the company uses similar stickers. So let’s dig deeper. As it turns out this module is produced or sold under the label LD0201 by a company called szsonicom. Google lists their website as malicious so I am not going to link to their website directly. Copy and Paste this URL on your own risk:
http://www.szsonicom.com/products/notebook/2015-12-07/29.html

Browsing their other products revealed a module called SON-FL02-VGA:
http://www.szsonicom.com/products/notebook/2015-12-07/41.html
Their pictures look really close to the module found in the EV100:

Product page SON-FL02-VGA (screenshot)

 

The EV100 diopter adjustment wheel looks like it was added on top of the module, you can see the very same wheel as present on the SON-FL02-VGA inside. Let’s have a look at the SON-FL02-VGA specs:

Technology Ferroelectric Liquid Crystal on reflective CMOS
Mode Field sequential color
Format 720 x 540
Active Area 2.96 x 2.97mm (4.95mm diagonal)
Input Grayscale 256 levels
Pixel Pitch 5.5um
Framerate 60/360 Hz (NTSC), 50/300Hz PAL
Brightness 200cd/m^2 or more
Contrast Ratio 150:1
Display Interface YCbCr(4:2:2)-parallel (16 data, Hd, Vd, Clock) or
YCbCr(4:2:2)-serial (8 data, Hd, Vd, Clock)
Control Interface Industry standard two-wire serial interface (smells like I2C)

At this point I can not be 100% sure if this is really the module found in an EV100 or just something similar. There is a lot of evidence that these modules are the same. If this is indeed the display used in the EV100 this table gives us some interesting information:

Resolution

The display is listed as 720 x 540 pixels. The good news is that this is exactly that what Eachine writes in the technical description. The bad news are that PAL video is defined as 720 x 576 pixels. So this might be the reason that some people complain about missing OSD lines. PAL video is most likely cropped at 540 pixels height, it makes no sense to rescale a PAL signal to fit into 540 lines as this would degrade the signal. However it looks like something strange is happening to NTSC when you look at the pictures posted on rcgroups. The EV100 seems to rescale and crop NTSC signals?! I have no idea why this happens and if this can/will be fixed in future firmware upgrades. Let’s hope so…

Drive / Control

The display is using a so called “Field sequential color” mode. This means that the display itself is basically a grayscale display and is illuminated by different colored light sources in a sequence. In simple terms the screen is successively illuminated by a red light source, then green, and finally blue. The slowness of the human visual processing combines this sequence into one steady image. This drive mode is commonly used in some types of projectors and e.g. google glass seems to use it as well. The listed framerate indicates that the screen is refreshed 6 times as often as the input signal, most likely the illumination pattern is RGBRGB to achieve a more stable impression.

I am not sure if the display itself is using the YCbCr (luma and and chroma components) color mode for data transmission or if this refers to the associated driver PCB. I would expect the display to be driven in RGB mode (red, green, and blue). This would also fit more to the 24bit wide data bus that can be seen on the pcb traces. However the FPGA might also do a conversion into the YCbCr format.

I have contacted the company in order to get a datasheet even tough I doubt I can expect a response at all. I will update this post if I get access to the datasheet.

That’s it for now. Further updates on my analysis will follow soon:

3 thoughts on “Eachine EV100 component analysis: Display module supplier and technical data

  1. Tom

    Thanks, this is great research! It’s a shame that the supplier doesn’t seem to have any product that would help with the fov. I guess eachine will have to look elsewhere and go back to the drawing board if they want to improve.

    Did you think of doing similar analysis on the Hyperion f640s?

    Reply
    1. fishpepper Post author

      Thanks! Right now I have no plans on buying and testing the F640s.

      Reply

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