AR/VR/MLA/Lenticular

VR/AR

 

While VR(Virtual Reality) displays a perfect virtual space totally disconnected from the real-world, AR(Augmented Reality) displays imaginary image on top of the real-world. Thus, optical parts used for these are different. However, both the VR and the AR have something in common which is they both must create virtual reality centered on images using eyes, and the machine must be lightweight and be low in volume.

For this reason, VR and AR certainly needs Fresnel technology.

We use PMAA with good optical quality for VR lens but also often use PVC. The lens production method frequently used are hot-press and injection.

Fresnel factory provides Fresnel lens needed in AR but also half mirrors and front surface mirrors as well.

 

Precautions when manufacturing VR, AR lenses

  • Optics design in consideration of display pixels
  • Fresnel quality management(Indentation pitch, Center)
  • Lens designed to minimize weight and volume of head mount equipment

 

Fresnel Factory has experience of developing VR lenses aimed to lighten weight and reduced volume and lenses for Netherland’s Aryzon AR machines.

 

 

<VR with Fresnel Factory Fresnel lens insdie>

 

<Aryzon Ar with Fresnel Factory optical elements>

 

Reference:


http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=107&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=123&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

 

 

Need for Fresnel lenses

HTV VIVE and Oculus Rift use Fresnel lens. We will explain why VR HMD needs lens and how the lens operate.

1) The first image shows the phenomenon when the eyes are looking at a general object. The image settles in the retina after passing through the pupil and the lens.

 

 

2) But for VR HMD, the display equipment is placed 3~7 centimeter in front of our eyes. When the subject image approaches too close to human eyes, the focal spot does not accurately settle in retina.

 

 

3) As shown above, to correct wrong focal spot, the lens is installed to the VR equipment. The installed lens functions so that the focal spot can properly settle like shown in the image below.

 

 

4) But in reality, the object from the display in front of you doesn't seem to be right in front of you, but you have to change the curvature of the lens to make it look a little further away in the space of real-world. Then, as shown in the picture below, you can make things visible in virtual reality, not just in front of you, but out beyond, as if they were somewhere in space. The problem is that if you try to solve it with a typical single convex lens, the lens will increase in size and weight.

 

 

5) So to solve such problem, Fresnel lens developed by a person named Fresnel is installed.

 

 

6) As shown in the picture below, the Fresnel lens makes the lights gather to specific focal spot using a principle shown below.

 

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Distortion and correction method for VR lens

 

To increase immersion, a wide FOV: Field of View must be provided. This can be done much more effectively when using a curved spherical display. However, such technology is very costly. In particular, providing a curved spherical display for equipment like HMD is probably prohibitive. Thus, an effective way to broaden the viewing angle (FOV) is to look at small rectangular images through a convex lens - usually all display units are square.

 

Such method is an easy way to broaden the FOV but problem follows. The image distortion. As shown below, when observed from right lens, it will be seen as the image on the left. This type of distortion phenomenon is called pincushion distortion because four corners of the image stretches.

 

To solve this problem, the barrel distortion is applied to the circular image. The characteristic of distortion is called barrel distortion because it looks like the following passage.

 

That is, by applying barrel distortion to the original image on the right as shown in the picture below, the resulting information received through the lens will look the same as the original image.

 

In general, if virtual reality images are not viewed through a series of lens devices, the reason that they appear like below is because the barrel distortion is applied.

 

 

Because the visual distortion described above can be calculated mathematically, it is common for programs that produce 3D virtual reality images using bicansi to be automatically processed by software.


Reference: http://truemind1.blogspot.com/2016/10/06-2-vr-distortion.html

 

 

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AR

<Aryzon AR with Fresnel Factory optical elements>

 

Reference: http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=123&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

 

Fresnel Factory supplies front surface and Half mirrors for AR produced by the sputter vacuum deposition system in the form of Film and Sheet.

For optical lens for AR that are not available in our homepage, please use Contact Us.

 

 

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Lenticular/MLA

 

Lenticular and MLA(Micro lens array) is essentially required optics that generates 3-D image. Volume matric is a special feature in glassless 3D image. It's a different imaging method than AR (Argument Reality) and VR (Virtual Reality) that we see often now.

Glassless 3D put out images suitable for Lenticular and MLA developed to realize three dimensional effect to displays such as LCD, LCOS, OLED and enables the user to see it through Lenticular and MLA. The origin of Fresnel Factory Inc. was development and manufacturing of beam projector so we know very well about not only the optical science but about display as well.

The Lenticular realizes three dimensional effect on the left and right, and MLA is able to realize the effect on upper, lower, right, and left.

 

Precautions when manufacturing

  • Optical design that suits display and target resolution
  • Lens side illumination for high quality image
  • Lens quality (Tip Radius, Value Radius)
  • Lens material and thickness that suits display
  • Production method appropriate for quantity used in the future

 

Fresnel Factory has experience with similar holograms and glassesless 3D displays from projection, and has development cases for rental and MLA for customers.

 

<3D hologram projector developed by Fresnel Factory>

 

<Glassless 3D display MLA for Fresnel Factory>

 

Reference:

http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=102&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=49&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

 

Through the experience of prototyping or mass production, we can design various types of optical quality, side illumination, and thickness of optics, which are the core of stereoscopic images, and we also have developed a film-type as well.

 

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Lenticular

 

 

The above drawing is a 32-inch lenticular sheet developed by Fresnel Factory. It’s a quality material PMAA lens manufactured with hot pressing method. Our quality material production method possesses superb quality and it is easier to manage compared to that of film laminating method mixed with complex materials such as PET, UV resin, PMMA, and OCA of our competitors. In general, it is advantageous to produce PMMA sheets hot pressing or pasting for large TVs that require a lens thickness of more than 1mm, and film-type lenses are suitable for small displays that require a lens thickness of less than 1mm (Smartphone, LCoS). Our Fresnel Factory can also manufacture molds for hot embossing roll-to-roll, which can produce PMMA single material less than 1mm. In 2019, we are planning to complete lenticular lens that can be applied to 70-inch 8K TV. Tilting degree of precision of 70-inch lenticular is 0.2 degree.

 

<Cross section of 32-inch lenticular observed by microscope>

 

What is lenticular?

 

 

 

 A three-dimensional lens of a lenticula is a collection of microscopic lenses that are semi-circular in each unit of transparent plastic, flat in the bottom, and has a waveform shape. When compressed and printed image by a specialized software is attached to the lens, it can create effects such as three-dimensional, conversion, video, and zoom.

By reconstructing flat images (2D) into three-dimensional print/output (3D), it refers to advanced print functions such as 3D image effects that overcome the limitations of conventional flat printing technology, allowing users to feel spatiality, realism, texture, and more than one image in a single print, Flip effects, and motion, Morphishing, and Zoom functions.

 

The most important factor in feeling three-dimensional is the binocular difference that occurs because your eyes are approximately 65mm apart in the horizontal direction.

 

  • The left and right eyes recognize two-dimensional images (the average distance between the two sides is 65 mm).
  • These two images are transmitted to the brain through retina.
  • The brain precisely fuses these images to display depth and realism of the 3-D image.
  • Such ability is called STEREOSCOPY.

 

With the Lenticular lens, the blocking effect of some images and the advancing effect of selective light can be used to obtain the effect of a three-dimensional image with a two-dimensional plane image.

 

 

Three-dimensional feel and image expression is possible using binocular disparity by lenticular film.

 

 

Binocular disparity caused by curving light on the lens’ surface

 

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MLA(Micro Lens Array)

 

Fresnel Factory Inc. possesses optical lens manufacturing technology for glassless 3-D display. In particular, we are the only company in Korea that has both integrated image-related lens technology and elemental image generation technology using Lenslet.

 

<MLA for glassless 3D display developed by Fresnel Factory>

 

Reference:

http://www.diypro.co.kr/bbs/board.php?bo_table=instance&wr_id=49&sca=3D+%EB%94%94%EC%8A%A4%ED%94%8C%EB%A0%88%EC%9D%B4

 

      

 

<Elemental image conversion algorithm for light field>

 

 

Reference:

https://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=2861

 

Please refer to our Design and Tooling documentation for micro lens array and lenticular production.
We at Fresnel lens manufacture micro lens array using following four methods.

 

 

Parts

There are currently two 32-inch lenslets developed. The 70-inch lenslet will be developed by 2015.
Please contact mjkim@diypro.co.kr for any questions regarding lenslet shown below.

 

 

Selection of Government Assistance Tasks for the Mid-term Agency between 2014 and 2016: Glassless 3D Display Devices and Optical Components
We are currently developing a display unit through the above tasks. Below is a schematic of the system.
(In order of, system plan, completed 50-inch glasses 3D device, and tile method for large-area implementation for advertising)

 

 

 

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