雙向過驅動式快速反應液晶透鏡於裸眼3D顯示器之應用

Abstract

為了得到更自然的立體影像，近年來已有許多專家及廠商投入立體顯示器的發展。大多數立體顯示器使用固定式的光學元件，但此種顯示器僅能提供3D影像，無法提供2D影像。因此，可切換2D、3D影像顯示器的發展便顯得重要。 為了改善固定式光學元件的缺點，液晶透鏡被廣泛應用並克服此問題，然而液晶有個問題是過長的反應時間，為了產生足夠的相位差，液晶核厚需要有一定的厚度，使得反應時間拖長。雖然在聚焦時能使用過驅動的方式加速達到3D效果，但要轉成2D模式時則純粹是關掉電壓，使其自然恢復。本論文的設計目標為能自由的快速切換於2D影像與3D影像的光學元件(雙向過驅動液晶透鏡，DFE-LC lens)。藉由設計電極的排列，另外搭配FPGA板等控制電路，製造出想要的聚焦與回彈的電場場域，進而控制液晶分子的導向，導致液晶核可以在透鏡型態與非透鏡型態間快速轉換，整體(ton+toff)的反應時間可以由原本自然操作情況下的10秒縮短至2.6秒，總反應時間加速了75%。這意味著在液晶核厚度較厚時(60μm)，除了能產生足夠的相位差形成透鏡外，還是能夠有效地將反應時間降低，如此一來，增加了液晶的機動性，使得未來立體顯示器功能上有更多發展的可能性，例如2D/3D快速切換或是掃描式的立體影像畫面。

Recently, many researchers invest in developing 3D display technology to produce more natural images from displays. Since most of display applications use the fixed optical components to display 3D images, the 2D images cannot be provided by the same displays. Thus, a 2D/3D switchable display is needed. To improve the fixed optical devices, liquid crystal lens has been used to overcome this issue widely. But there is an issue of liquid crystal lens. In order to get enough phase retardation, the liquid crystal needed to be bulk which results in long response time. Although the response time can be reduced by using overdriving method as focusing, the liquid crystal molecules recover to initial state slowly by turning off the power. Therefore, the time from 3D to 2D mode is long. In this thesis, we designed an optical component which was driven by low operating voltage and can switch between 2D and 3D modes within a fast rate. In order to get the electric field which is desired, we design the electrode arrangement and use FPGA as a controller. The purpose of these works is to re-orientate the liquid crystal molecules which result in switching between lens on state and lens off state. The total response time can be improved about 75% (from 10s to 2.6s). The advantage of the dual direction overdriving method is that the response time can be reduced even though the cell gap is thick. This makes the LC lens become more potential for applying in 3D display such as fast 2D/3D switching and scanning type 3D images.