| 摘要 |
PURPOSE: To improve the contrast of a polymer dispersion type guest-host liquid crystal display device. CONSTITUTION: The liquid crystal display device is equipped with an upper substrate 1 having a transparent electrode 3, a lower substrate 2 having a reflecting electrode 4, and an electro- optical body 5 held between the substrates. The electro-optical body 5 has a laminated structure of a first liquid crystal layer and a second liquid crystal layer 7. The first liquid crystal layer has dispersion of liquid crystal grains 9 containing a dichroic dye 8 in a polymer medium 10, while the second liquid crystal layer 7 consists of uniaxially oriented nematic liquid crystal molecules having optical anisotropy. When no voltage is applied, the incident light is partly absorbed by each liquid crystal grain 9 in the first liquid crystal layer 6 while the rest of the light is transmitted. When voltage is applied, most of the incident light is transmitted through the liquid crystal grains 9. In the second liquid crystal layer 7, the polarization direction of the light transmitted through the liquid crystal grains 9 and reflected by the reflecting electrode 4 is rotated so that at least part of the light is converted into a state which can be absorbed by the liquid crystal grains 9. When voltage is applied, the second liquid crystal layer 7 loses the uniaxial orientation and loses its optical anisotropy. In this state, most of the light transmitted through liquid crystal grains 9 and reflected by the reflecting electrode 4 is again transmitted through the layer 7 to be allowed to enter again in the liquid crystal grains 9. |
