Shuichi Kawabata

Alicyclic Polyimides based on bicyclo[2.2.1]heptane- 2,3,5,6-tetracarboxylic 2,3-5,6-dianhydrides

The alicyclic polyimides were prepared by reacting bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic-2,3-5,6-dianhydride (BHDA) with aliphatic or aromatic diamines in hexamethylphosphoramide. The poly(amic acid)s possessed inherent viscosities (νinh)in the range from 0.13 to 0.38, and they formed free-standing and flexible films after being cast then cured. The fully alicyclic polyimide films exhibited a cutoff around 230 nm, and are transparent even in the near infrared region. The optically estimated ε of the fully alicyclic polyimides was about 2.6. All the alicyclic polyimide possessed negligibly small birefringence below 10-4. Semi-aromatic polyimide PI(BHDA + 1,3-BAB) had good thermal stability with no significant weight loss up to 350°C, and the T 5 was around 450°C, although the T g was as low as 197°C. All polyimides exhibited broad dispersive peaks of diffraction around 16° (2τ). The PI(BHDA + BBH) film possessed a tensile modulus of 2.05 GPa and a tensile strength of 52 MPa, and these values can compete in terms of strength with those of a commercial polycarbonate.

Alicyclic polyimides – a colorless and thermally stable polymer for opto-electronic devices

Alicyclic polyimides were prepared from polyalicyclic monomers using a two-step method. Light absorption of polyimides was elucidated from quantum chemistry. The alicyclic polyimide films were colorless, and the transparencies in the visible region were over 85%. The semi-aromatic polyimide films had an average refractive index range of 1.599 to 1.617, and that of a full-alicyclic polyimide was 1.522. The birefringencies were nearly zero. Semi-aromatic polyimides were soluble in aprotic polar solvents like DMAc. However, the non-aromatic (full-alicyclic) polyimides were insoluble except sulfuric acid. All the alicyclic polyimides have the 5% weight loss temperatures in nitrogen over 450 °C, and 400 °C in air. They possess glass transition temperatures over 280 °C. The alicyclic polyimide films have a tensile modulus range of 1.3–3.0 GPa, and a tensile strength range of 38–145 MPa. Especially semi-aromatic polyimide films display high strength. They have an elongation at break range 5–30%. All the polyimides exhibited amorphous patterns and broad dispersive peaks of diffraction around at 16° (2θ).

Modified transmission type four-detector polarimeter

A four detectors polarimeter is originally invented by Azzam et. al. We have modified their idea and developed a new four detectors polarimeter of a transmission type (T-FDP) which has some advantages over the conventional one. Further modification of our T-FDP to the M-TFDP is reported. The alignment procedure of the optical system is also discussed as the application of the M-TFDP to ellipsometry.

Observation of silver film growth using an in situ ultra-high vacuum spectroscopic ellipsometer

Abstract Most metal films grow discontinuously in the early stages of the deposition. However, the optical behavior of discontinuous metal films is not yet well understood. We observed the growth process of Ag films on a Si substrate covered with a natural oxide layer using an in situ ultra-high vacuum spectroscopic ellipsometer over the spectral range from 260 nm to 860 nm. The growth process of the film was analyzed by means of an effective medium theory, which takes into account the discontinuous structure of the film. The analysis of the Ψ–Δ trajectory of the Ag film suggests that surface roughening occurs in the growth process.

Design and Prospect of the Multi-media Directions for Fundamental Experiments of Physics

Development and diffusion of information technology (IT) have opened a new possibility in education. Digital technology will also provide a variety of teaching methods in education. It can easily merge each media into a multi-media and this will enable to provide new directions for laboratory work with virtual experiments. We will present the contents of the multi-media directions of the fundamental experiments of physics and also will discuss the versatilities of the multi-media directions.

Real-time Stokes polarimeter using three polarized beam splitter (Conference Presentation)

This paper describes real-time, very small and cheap Stokes polarimeter using three polarized beam splitters (PBSs). Each s1, s2 and s3 of Stokes parameters is measured by the PBSs. However this technique has to separate three beams keeping unknown incidental polarization state. To overcome this problem, three same normal beam splitters (BSs) are possible to separated two beams keeping polarized state. An alignment of three BSs is set orthogonal in transmission part and reflection part. In transmission part, the polarization state after two BSs can be canceled change of polarization state of first BS by change of second orthogonal BS. In reflection part is same theory. If you set two pear of this keeping polarization beam splitter, you can separate three beams keeping incidental polarization state. After separated beams, three PBS can measure Stokes parameters easily. At first we checked effect of the keeping polarization beam splitter using spectoscopic Mueller matrix polarimeter. We got Mueller matrixes having max 3.3% value of transmission and reflection from unit matrix during from 450nm to 700nm. In second we checked Stokes parameters after a rotating polarizer and a quarter wave plate in this Stokes polarimeter. In two condition results, an error had 5.6%. Finally we checked measurement speed of this real-time Stokes polarimeter using rotating quarter wave plate. From this result this Stokes polarimeter is possible to measure Stokes parameter in 15Hz. This measurement speed depends on detection speed of six PIN photodiodes and transfer speed of AD convertor.

High-speed Transmission type Four Detectors Polarimeter and its Applications

A high-speed transmission type four detectors polarimeter (High-speed TFDP) is developed. The High-speed TFDP is applied to the time-resolved measurement of the fast phenomenon such as liquid crystal alignment for example.

Real-time Measurement of the Thickness of Soap Films with the Polarimeteric Interferometer

A new type of the polarimetric interferometer is introduced. It consists of the Mach-Zehnder interferometer and the polarimeter as the polarization detector. The critical thickness of soap films were measured with the polarimetric interferometer.

Development of the multi-media directions for the virtual laboratory work of physics: (Experiments of the geometrical optics)

The development and the prospects of the multimedia directions of laboratory work of physics are discussed. The experimental procedures are demonstrated by using the visual aids in the directions. The multi-media directions consist of photos and video clips of the demonstration experiments. The multi-media directions will help the student to learn the laboratory work virtually before the experiment. Some of the multi-media directions are intended to be seen on the Internet so that the student can refer to the directions in the preliminary study of the laboratory work. This virtual learning will help the real laboratory work of the student.

In-situ ultrahigh vacuum spectroscopic ellipsometry

Polarization modulated spectroellipsometer was utilized to monitor, in-situ, deposition of Ag on Si substrate. The angle of incidence was determined using a Si substrate covered with native oxide. In the wavelength region of 550 nm to 700 nm, the ambiguity of the angle of incidence was within 0.2 deg. A plasma resonance peak manifested in reflectance spectrum around 350 nm increased and shifted to shorter wavelength as the deposition time increased from 1 sec to 10 sec. (Delta) (Psi) trajectory approached to a simulation curve of a continuous film as the deposition time increased to 40 sec where the film thickness was estimated to be 20 nm.