應用微光學元件於液晶顯示器生成互動式漂浮三維影像

Abstract

有著三維凌空觸控應用功能的漂浮式三維顯示器極具潛力成為下一世代的顯示科技技術，毫無疑問地，如同科幻電影一般，能夠與其互動甚至觸碰到觀看中的漂浮三維影像是令人感到驚喜且備受期待的。與一般正視的三維顯示器相比，使用者會於斜向視角觀看漂浮式三維顯示器，因此能夠輕易地感受到漂浮三維影像的立體感知資訊，進而大幅度地提升使用者的觀看經驗。然而現今的漂浮式三維顯示技術存在著諸多限制，如不適用於即時應用、沒有互動可行性及系統過於龐大等問題，因此於本論文中，我們嘗試應用不同類型的微光學元件於液晶顯示器上，以實現一能夠顯示具有互動可行性的漂浮三維影像且體積輕薄的漂浮式三維顯示器。 首先，藉由多使用者三維光學膜，一具有指向性時序型測發光式背光系統的時間多工三維顯示器的可觀賞者數量由一位增加至三位。其次，我們提出點狀視差屏障以解決一般視差屏障所造成的黑線問題，並利用微稜鏡片將光導向斜向視角，藉由微稜鏡，斜向視角的影像品質大幅度地提升，平均亮度增加10倍，且平均重影(crosstalk)減少了四分之三，進而實現了一斜向觀賞 視角為60度且平均重影為10%的四視圖(four-view)漂浮式三維顯示器。 其次，我們進行了一系列的人因實驗以研究在雙眼視差系統下三維凌空觸控應用的視覺及觸控問題。經由實驗發現，由於在三維凌空觸控應用下單眼調節(accommodation)及雙眼聚合(convergence)的不匹配會更為嚴重，導致觸控準確度下降至不到40%，因此我們提出虛擬參考物及影像反饋等操作模式以增加觸控準確度，藉由虛擬參考物及影像反饋，觸控準確度可分別提升至60%及90%以上。 最後，我們提出了斜向觀看集成式影像(integral image)系統以實現一在空間中真實還原影像資訊的漂浮真實三維影像，漂浮真實三維影像理論上能有效地改善在雙眼視差系統中人眼反應不匹配的問題，因此能夠提供一更可靠的三維凌空觸控人機介面。我們利用了非常簡單的設備實現了一可攜式漂浮式三維顯示器：4.7吋智慧型手機及微透鏡陣列。藉由調整顯示器及微透鏡陣列中玻璃基板厚度和影像傾斜角，實現了一不只漂浮且站立的真實三維影像。

A floating 3D display with 3D air-touch application has great potential to be the next generation of displays. It is definitely amazing and exciting that someday users can interact and touch the floating 3D images they are watching, like science-fiction movies show. Comparing with the conventional 3D images from a conventional 3D display, users are at an oblique viewing angle to watch the floating 3D display rather than in the normal direction; thus, users are able to perceive the depth perception of the floating 3D images simply. It means that there is a great enhancement for the watching experience through the floating 3D images. However, there are several limitations for current floating 3D display technologies, including not suitable for the real-time application, no interactive feasibility, and bulky apparatus. Therefore, in this dissertation, micro-optical components are proposed to apply to a liquid crystal display for implementation of a compact volume floating 3D display to create a floating 3D image with the interactive feasibility. First, the multi-user 3D film is proposed to increase the number of observers from one to three for a time-multiplexed 3D display with a directional-sequential side-emission backlight system. Second, the dot-like parallax barrier which has an arc-shaped edge profile and micro prisms are proposed to improve the black stripe issue and direct the light from the normal direction to the oblique viewing angle respectively. The image quality at the oblique viewing angle is increased significantly for the average crosstalk is reduced by three-quarters and the average normalized luminance is enhanced by a factor of 10. Accordingly, a four-view floating 3D display that the oblique viewing angle is 60 degrees and the average crosstalk is 10% is implemented. Secondly, a series of human factor experiments are performed to understand the visual issues and touch mismatches for the 3D air-touch application in the binocular disparity system. The touch accuracy on the binocular disparity system decreases to lower than 40% because there are two kinds of conflicts: the conflict between accommodation focusing on the 3D display and convergence focusing on the 3D images and the conflict between accommodation focusing on the 3D display and accommodation focusing on users’ fingertips. Therefore, the virtual references and image feedback are proposed to improve the touch accuracy, and the results show the touch accuracy is enhanced to more than 60% and 90% respectively. Finally, the oblique viewing integral image system is proposed to generate a floating true 3D image which has the potential further improve the two conflicts on the binocular disparity system ideally and provides the full parallax. A portable floating 3D display is implemented with simple equipment: a smartphone with a micro-lens array. Through adjustment of the thickness of the glass substrate between the display and micro-lens array and the image tilt angle, not only floating but also standing true 3D images are realized.