Transmissive Mirror Device based Near-Eye Displayswith Wide Field of View
Kazuki Otao

Yuta Itoh

Kazuki Takazawa

University of Tsukuba
Pixie Dust Technologies, Inc.
kazuki.otao@pixiedusttech.com

University of Tsukuba
Pixie Dust Technologies, Inc.
atuyoti@pixiedusttech.com

University of Tsukuba
Pixie Dust Technologies, Inc.
kazuki.takazawa@pixiedusttech.com(a)Hiroyuki Osone

Yoichi Ochiai

University of Tsukuba
Pixie Dust Technologies, Inc.
soneo@pixiedusttech.com

University of Tsukuba
Pixie Dust Technologies, Inc.
wizard@slis.tsukuba.ac.jp

Oﬀ-the-shelf HMD

TMD(b) Graphics(c)Lumus DK-52, Meta Pro 40
SONY SED-E1 20
Epson BT350 23

Background
ObjectOurs 100

Figure 1: (a) A prototype of our TMD-based HMD. Our HMD is easily constructed with a combination of off-the-shelf HMD
and TMD. (b) Obtained image of a prototype display with aerial graphics and see-through background. (c) A comparison ofthe field of view of our prototype display. The viewing angle of our HMD prototype was 100 degrees.

ABSTRACT
We present a transmissive mirror device (TMD) based near-eye seethrough displays with a wide viewing angle and high resolution forvirtual reality and augmented reality. In past years, many opticalelements, such as transmissive liquid-crystal display (LCD), halfmirror, waveguide and holographic optical element (HOE) havebeen adopted for near-eye see-through displays. However, it isdifficult to obtain wide field of view with see-through capability
for beginner developer. To accomplish this, we develop a simple
see-through display that easily setup from a combination of off-theshelf HMD and TMD. In the proposed method, we render “virtuallens,” which has the same function as the HMD lens in the air. Byusing TMD, it is possible to shorten the optical length between thevirtual lens and the eyeball. Therefore, the aerial lens provides awide viewing angle with see-through capability. We demonstrate a
prototype with a diagonal viewing angle of 100 degrees.

CCS CONCEPTS• Hardware → Displays and imagers;
SIGGRAPH ’18 Emerging Technologies, August 12-16, 2018, Vancouver, BC, Canada© 2018 Copyright held by the owner/author(s).
This is the author’s version of the work. It is posted here for your personal use. Notfor redistribution. The definitive Version of Record was published in Proceedingsof SIGGRAPH ’18 Emerging Technologies, August 12-16, 2018, https://doi.org/10.1145/3214907.3214908.

KEYWORDS
augmented reality, near-eye displays, transmissive mirror device
ACM Reference format:
Kazuki Otao, Yuta Itoh, Kazuki Takazawa, Hiroyuki Osone, and Yoichi
Ochiai. 2018. Transmissive Mirror Device based Near-Eye Displays with
Wide Field of View. In Proceedings of SIGGRAPH ’18 Emerging Technologies,Vancouver, BC, Canada, August 12-16, 2018, 2 pages.
https://doi.org/10.1145/3214907.3214908

1INTRODUCTION

Development of mixed reality with wide viewing angle is an important issue for researchers and engineers [Maimone et al. 2014].
In recent years, several studies have proposed employing opticalelements, such as half-mirrors, free-form optics, and waveguidefor near-eye see-through displays. However, these optical elements
suffer from the essential problem that the optical path length between the virtual lens and the eyeball become too long (Figure 2(a)). It provides only a narrow viewing angle.
To solve this problem, we propose a novel near-eye displays using
TMD [Maekawa et al. 2006] which consists of micro corner reflector
array that can render real images in the air. In order to enableaerial images without special glasses, TMD is usually applied toaerial imaging systems and aerial interaction systems [Makino et al.
2016]. In contrast to previous work, we explore the combinationof eyepiece interfaces and TMD. By using TMD, the physical lens

SIGGRAPH ’18 Emerging Technologies, August 12-16, 2018, Vancouver, BC, Canada(a)(b)Half-Mirror + Eyepiece

EyeHalf-Mirror

PhysicalLens
LCD

Displayed Image

AerialImage

TMD + Eyepiece
Virtual Lens

Otao et al.

(a)(b)

(c)

(d)

TMD

PhysicalObject
VirtualLens

Long optical path, Narrow viewing angle

Short optical path,
Larger viewing angle

Figure 2: (a) Half mirror and physical lens configuration.
The virtual lens appears between the mirror plate and thephysical object. (b) TMD and physical lens configuration.
The virtual lens appears between the eyeball and the mirrorplate. Since the optical path length between the mirror plate
and the eyeball is shortened, the viewing angle increases.

placed in the TMD behaves as an near-eye aerial lens. The userobtains the same experience as with the VR-HMD by looking into
the virtual lens in the air (Figure 2 (b)).
We emphasize that TMD-based HMD never demonstrated inpublic exhibitions although some study was presented [Otao et al.
2017, 2018]. It is desired to present TMD-based HMD for computer
graphics community.

2SYSTEM OVERVIEW

We employ off-the-shelf HMD and consumer available TMD1 .
An Oculus Rift Development Kit 2 (Oculus VR, LLC) 2 isused as the HMD in the prototype. The resolution of LCD is1134 × 750 (367 × 750 per eye) and the size of LCD was
125 mm × 7 mm. We remove the LCD and the lens from the HMD,and set it in a 3D printed frame. The TMD size of 140 mm × 116 mm
and pitch size of 0.5 mm is adopted. The overview of our prototype
is shown in Figure 1 (a).
The weight of the basic system (including LCD, lens, and TMD)
was 242 g, and the weight of 3d printed frame was 189 g. Theviewing angle of the original Oculus Rift DK2 is 110 degrees. The
viewing angle of our HMD prototype was 100 degrees (Figure 1(c)).
This type does not require any special software to render image
sources, so that existing VR content can be applied. The obtained
image in this prototype is shown in Figure 1 (b) and Figure 3.

3 DISCUSSION
3.1 See-Through Capability
As shown in the Figure 1 (b), a TMD reduces brightness from thescenery. There is a trade-off in consideration of the material andstructure of TMD for observation of a comfortable real environment.
Alternatively, a beam splitter can be used for the optical system infront of the eye.
1 https://aska3d.com/en/ (last accessed May 16th, 2018)
2 https://www.oculus.com/rift/ (last accessed May 16th, 2018)

Figure 3: The image obtained from our prototype display. (a)SIGGRAPH Logo. (b) A bottle on the counter. (c) Color pattern. (d) Text information.

3.2

Ghost ImageThe TMD causes double reflection images to appear diagonally.
This is undesirable because ghost image obstructs the user’s line ofsight. To cope this problem, we have to consider to cut unnecessary
light path.

3.3

Polarizing Filter

Essentially, chromatic aberration and diffusion do not occur since
TMD is just a mirror. However, slight chromatic aberration anddiffusion are seen due to manufacturing problems. It is expectedthat such errors will be reduced due to improved manufacturing
accuracy. Also, we found that it is effective to adopt a polarizing
filter to the LCD to reduce such diffusion.

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