Tsuyoshi Hotta

Mass-produced color graphic arts holograms

We have been developing various types of holograms. In this paper mass-produced color graphic arts holograms are discussed. The TRUE IMAGETM hologram, as it is known in Japan, is a volume-type hologram which diffracts selected wavelengths of the ambient light to selected desired angles. When replicating the TRUE IMAGETM, three lasers are used simultaneously or independently. There are four beneficial characteristics of the TRUE IMAGETM hologram; (1) Repeatable mass product techniques and few defects: a direct lamination method has been developed. (2) Looking bright and clear under fluorescent light: specially designed masters and replication conditions allows TRUE IMAGETM holograms to be seen under fluorescent light. (3) Stable chromaticities: expressing full color by developing objects, paints, mastering process and replication process. (4) Good environmental stability: use of effective adhesive films. In this paper, the first characteristic is mainly discussed.

Holographic light-control film for liquid crystal displays

We have been developing various holographic optical elements (HOEs) and holograms. In this paper holographic light control films (HLCFs) for use with reflective monochromatic type liquid crystal displays (LCDs) are discussed. The HLCFs are volume type holograms which diffract selected wavelengths of the ambient light to specific angles. Using HLCFs as reflectors in conjunction with LCDs allows the concentration of reflected light to specific viewing areas. Three beneficial characteristics of HLCFs, weak dependence upon incident light angles, good control of diffracted color and excellent environmental stability are described. (1) Weak dependency on incident light angles: Specially designing master holograms and replication conditions allows the production of HLCFs only depend weakly on the angle of the incident light. (2) Control of diffracted color: Varying process conditions allows the creation of HLCFs which diffract specific colors. (3) Stability during and after environmental tests: Using DuPont photopolymers resulted in good stability for both low and high temperatures and high humidity test conditions. In addition, the TEM pictures of the cross sections were shown.