Norio Miyake

A Decentering Zoom Lens in a Stereomicroscope

We can move an entrance pupil from on-axis to off-axis by decentering lens groups of a zoom lens. This decentering zoom lens can contribute to miniaturization of objective lenses of a stereomicroscope.

Decentering zoom lens in stereomicroscope

We can move an entrance pupil of a zoom lens from on-axis to off-axis by decentering lens groups of a zoom lens. This decentering zoom lens makes an objective lens of a stereomicroscope small. As a result, we can develop a stereomicroscope with high magnification and high resolution.

Perfect Zoom System which enables both a zoom ratio of 25:1 and a high-resolution in stereo microscope

A stereomicroscope can stereoscopically observe an object with protrusions and recesses as if the object were viewed by both eyes. Such stereomicroscopes use an optical system to create two slightly different viewing angles of an object. The different images are both enlarged and viewed through two eyepieces. Each of the observation optical systems includes a variable magnification mechanism which is called a zoom lens system. In recent years, a demand for stereomicroscopes that can observe a wide variable magnification range has been increasing along with the diversification of applications. However, there are no stereomicroscope zoom lenses with both a high resolution and a large zoom ratio. We developed the “Perfect Zoom System” which can reduce the light flux diameter going through the objective lens in the low-power state. In the “Perfect Zoom System”, the zoom lens groups move along not only the optical axes but also perpendicular to the axes. Therefore, the objective lens could be made smaller by decentering the G2 and G3 group lenses in zoom lens group. We achieved a high resolution and a zoom ratio of 25:1.

Evaluation of the no-disparity realistic image from a sense of presence and low fatigue

We evaluated an observer’s fatigue and a sense of presence, in observing the no-disparity realistic image (NDR image) [1-3]. NDR image is consisted of two images (right and left image). Right image is created by shifting all pixels in left image same amount. Consequently, there are no disparities in all area of NDR image. NDR image which is reconfigured the contents that contain image with large disparity might have a possibility that it suppress an observer’s fatigue and let him feel high presence. Subjects observed three conditions videos (stereoscopic, NDR and 2D). Subjects observed two videos in each condition. Each video was 30 minutes. There were scenes with large disparity (more than 5 degrees) in videos. Subjects responded SSQ (Simulator Sickness Questionnaire), VAS (Visual Analogue Scale) for fatigue and questionnaire on realism and were measured CFF (Critical Frequency Fusion), accommodation tremor, stereoscopic vision test, ocular position measurement and eye sight test. Results showed that NDR image let observer feel high presence and an observers fatigue was low. NDR image is effective, even if contents which contain large disparity are converted into NDR image.