3D Display

Over the past decade, NDIS has developed glasses-free 3D display technologies and produced and sold various 3D LCD modules for smart phones, PMPs, and PDFs using the parallax barrier technology.
The company also developed the highest level of 2D/3D switchable display samples using the LC lens technology.

3D Auto-Stereoscopy with NDIS's state of the art 3D technologies allow users to feel spatiality, distance, reality and solidity from a 2 Dimensional display and to experience real 3D effect.

Two main approaches to achieve spatial multiplexing: Parallax barriers and Lenticular systems

3D Auto-Stereoscopy results from the separation of images between two eyes, which is called Binocular Disparity. When viewing the same object, the left and the right eyes observe different sides of the object and these two images are mixed in our brain to feel 3D images.

1. Parallax barrier technology

We can experience real three dimensionality without grasses when images are displayed utilizing parallax barrier. The parallax barrier is a series of vertical slots which are carefully designed to focus pixels in different directions.

In other words, Parallax barrier consists of masks that contain vertical apertures to cover the light at certain angles.

A parallax barrier is placed on the top of main TFT LCD (or OLED) and can be switched on and off.
When off, the LCD acts normally and the screen looks the same as to a normal LCD. In 2D Mode, parallax barrier dose not divide light. Right and left eyes of a viewer receive the same light so that the viewer can see conventional images.
When on, for the 3D Viewing, parallax barrier divides light so that right and left eyes of a viewer receive different light. Therefore the viewer can see stereoscopic images.
This configuration is known as a two-view autostereoscopic display.

wikipedia

Multi-view

However, there are some practical problems. The viewer must stay in the right position or a pseudoscopic image is produced. The larger the depth is, the larger the visual strain becomes.  These limitations can be overpassed by increasing the number of views, multi-view

In multiview displays, multiple different images are presented in front of the display.

The loss of resolution caused by multi-view 3D can be solved through very high-resolution displays

 e.g. 3D mode with high-definition resolution and 2D mode with ultrahigh-definition 4K resolution.

       QFHD (quad full high definition), 3840 * 2160 pixels

Flexible parallax barrier

In most cases, parallax barriers are made of glass substrates.

NDIS has developed a world first flexible 3D Display, Film type 3D LCD(F-LCD).

The F-LCD has a good stability for shock or impact since it has substantial walls inside the flexible top and bottom substrates to protect LCs, which guarantees no image distortion.

The flexible LCD with its own advantages such as bendable, unbreakable, light and thin has the same characteristic of electro-optics as the glass LCD.

Film type 3D Barrier LCD is quite suitable in hand held devices especially glasses free 3D Smart Phones since its thickness and weight are half and 1/10 those of glass LCD respectively.

The F-LCD technology can be used for various applications such as smart phones, tablets, e-books, game consoles, PMPs etc.

2D                                                 3D

Plastic Barrier

Recycling technology for brighter 3D

In the 3D mode, the brightness is reduced by the ratio of the slit area passing through the light of the parallax barrier to the total area (open ratio). For example, in 8-view 3D, the open ratio is 12.5% and 3D brightness is reduced to 1/8 of the 2D brightness.

Recycling technology developed recently by NDIS can increase the brightness in 3D two times.

         Existing Parallax Barrier                                           Recycling Parallax Barrier

(NDIS's recycling technology - Recycling the blocked light)

When using a linear light source: By reflecting the light blocked in the barrier area and recycling it, the light is collected into the slit area to realize a bright light source in 3D mode.

When using a surface light source : Implement a surface light source by changing the barrier area to transmit light in 2D mode.

Recycling Barrier Type 10.1" Display

2. LC based lenticular lens technology

Parallax barrier technology has drawbacks such as lower brightness, loss of resolution, small viewing angles(?), and crosstalk, which is caused by diffraction and it is difficult to suppress.

To improve the function of this type of system, lenticular technology based on microlenses can be used.

Principle of LC lenticular lens

(2D Mode)

The images from the left pixel and the right pixel can be seen by the two eyes at the same time. Therefore, the display remains the original 2D display.

(3D Mode)

Microlenses deviate the light to certain directions corresponding to each different eye.

For each microlens, the image coming from the right pixel can only be seen by the left eye, while the image from the left pixel can only be detected by the right eye. By combining these two images, our eyes will see 3D images out of the 2D panel.

Published 2013 in Optics express

NDIS's multi-view 2D/3D switchable LC lens display

NDIS recently developed a 8-view 2D/3D switchable display with 10.1" screen using its LC lens technology.

Our technology accomplised lowest level of crosstalk, 2% on average and no luminance change between the 2D and 3D mode, which mean it has one of the best autostereoscopic quality .

How to mitigate resolution reduction in 3D

To mitigate resolution reduction in 3D, the LC lenses are placed with a small angle to distribute the loss of resolution vertically and horizontally.
The loss of resolution caused by multi-view can also be solved through very high-resolution displays.

  e.g. 3D mode with high-definition resolution and 2D mode with ultrahigh-definition 4K resolution.

Lenticular Lens Type 10.1" Display

Future of LC lenses

LC lenses working with unpolarized light produces a considerable increase in the optical efficiency. Also switching speed and a reduction in crosstalk should be solved for various applications of LC lenses.

LC lenses have many interesting properties for their practical use, for example, small size, lightweight, low driving voltages, low power consumption and transmissive/reflective operation modes. They also have great advantage in a focal length tenability by voltage.

For example, a cylindrical LC microlens array has rotary optical power and tunable focal length capability.

For ophthalmology

Moreover, the lens power of LC lenses is not only electrically tunable, but it can also be positive or negative, which has interest for ophthalmic lenses.

Liquid crystal lenses can correct myopia impact.

Commercial glasses based on LC lenses were developed in 2011.

They have a switchable focal distance solving the problem for patients that require different types of glasses for different activities.

For AR/VR

LC lens capable of tunable focal length makes AR/VR optics into an auto-focusing system. This technology creates a more vivid, comfortable and immersive 3D experience and relieves negative effects arsing from AR or VR such as blurry vision, nausea and headaches.

Such problems are caused in current VR/AR devices, since virtual objects are displayed at different virtual distances from the user and the device’s static optics system which cannot to synchronize the optical signals with the varying distances.

NDIS's vision

As mentioned above, future prospects of LC Lens technology are very bright.

So, utilizing LC Lens technology and optical technology of NDIS, we plan to advance into the AR market such as Smart glasses by completing tunable focal length technology in the near future.