We first came across the technology of fresnel lenses in 3D-printers when we were searching for the difference between the Elegoo Saturn 8K and Elegoo Saturn2 8K resin 3D-printer. At first it looked like the printers were very similar, but when you have to look at the small letters and details to see the differences between these 3D-printers. To make it easier, we compiled a table below to compare the technical specifications. next to looks, there is one specification that is different between the Elegoo Saturn 2 8K and Elegoo Saturn 8K.
| Elegoo Saturn 8K | Elegoo Saturn 2 8K | |
| System | EL3D-3.0.1 | EL3D-3.0.1 |
| LCD Screen pixels | 7680*4320 pixels | 7680*4320 pixels |
| Pixel size | 28,5 micron | 28,5 micron |
| Build size | 123 x 218 x 250 mm | 123 x 218 x 250 mm |
| Printing speed | 30 – 70 mm/h | 30 – 70 mm/h |
| LED’s | 28 Matrix UV light source | 48 LED’s with Fresnel lens |
| Wavelength | 405 nm | 405 nm |
As you can see with the LED system used, the Elegoo Saturn 8K uses a matrix light source with 28 single LED’s. This technology is quite standard amongst the latest monochrome resin 3D-printers. With its new system the Elegoo Saturn 2 8K, the only differences that we can see are the looks of the machine and the new type of light source. this printer uses an arrey of 48 LED’s with fresnel lenses.
What does a matrix light source look like?
Currently the matrix LED technology is widespread used within the resin 3d-printing community. in the image below you can see how it looks like. There are a multitude of LED’s below the LCD screen. These LED’s are not homogeneous emitting light at the complete LCD screen and therefore a matrix of domes is placed over the LED’s. This will create a diffuse light so you have a better print performance. Already a big improvement over the first models of LCD / MSLA printers were the LED’s were positioned directly beneith the LCD mask.
Image by Elegoo: the matrix LED inside the Elegoo Saturn.
What is a fresnel lens?
A fresnel lens is a different type of lens. instead of the standard lens, it is a lens manufactured with grooves in it so the light path is changing from a single point which exposes to all sides, to a straight light path as you can see below.
Image by Edmundoptics.eu: Light Collimation of a Point Source with a Fresnel Lens
Are there benefits for resin 3D-printing when using fresnel lenses? We have to see these type of printers in action before we can give a hands-on experience. In theory can guide the light beams emmited from the LED’s below with a perfect straigth light path before hitting the masking LCD. There is a possibility that this will give less distortion and potentially better accuracy. Although the Matrix UV light used in in the previous models was already doing that quite well. Time will tell if these lenses will make a big impact in resin 3D-printing. See the video below to learn more about these type of lenses explained by an expert.
Currently there is one 3D-printer that has these type of lenses.
Photopolymers for LED matrix or fresnel based resin 3D-printers.
The 405nm LED Matrix light source has proven itself and all common 405nm resins are compatible on this type of printer. Looking at the minor technology change, use of similar open systems and wavelength, it is expected that all resins that worked on the 405nm LED matrix light, will also work on the Fresnel lens technology. Happy printing if you happen to be the first lucky few to get your hands on this new kind of fresnel resin 3D-printers! If you have experience with this type of printer, feel free to share your story with us at info@liqcreate.com.
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