Measuring method of liquid crystal pretilt angle and measuring equipment of liquid crystal pretilt angle

• US 6,317,208 B1
• Filed: 12/01/1998
• Issued: 11/13/2001
• Est. Priority Date: 12/02/1997
• Status: Expired due to Fees

• Current Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Original Assignee: NEC Corporation
• Inventors: Hirosawa, Ichiro
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Nguyen, Tu T.
• Application Number:
  US09/201,824
• Time in Patent Office: 1,078 Days
• Field of Search: 356/364, 356/365, 356/366, 356/367, 359/93, 359/94, 250/225
• US Class Current: 356/364
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration

Abstract

By setting the linearly polarized light with normal incidence on the liquid crystal sample 3 and rotating the liquid crystal sample 3 on a rotation stage 7 within plane, the dependencies of the amplitude ratio as well as the optical retardation of the transmitted light on the azimuth of the liquid crystal sample, with respect to the polarization direction of the incident light, are measured. From these measured results, a liquid crystal pretilt angle is determined.

Claims

1. A method of measuring a liquid crystal pretilt angle which determines a liquid crystal pretilt angle by setting the linearly polarized light incident on a liquid crystal sample and measuring the polarization of the transmitted light thereof;

wherein;

said linearly polarized light is normal to the surface of the liquid crystal sample in incidence; and

by rotating said liquid crystal sample within plane, the dependencies of the amplitude ratio of said transmitted light as well as the optical retardation of said transmitted light on the azimuth of the liquid crystal sample with respect to the polarization direction of the incident light are measured and thereby the pretilt angle of said liquid crystal sample is determined.

2. A method of measuring a liquid crystal pretilt angle according to claim 1, wherein said dependencies of the amplitude ratio of said transmitted light as well as the optical retardation of said transmitted light on the azimuth of the liquid crystal sample with respect to the polarization of the incident light is measured, by rotating a ¼

-wave plate placed behind said liquid crystal sample.

3. A method of measuring a liquid crystal pretilt angle according to claim 1, wherein said dependencies of the amplitude ratio of said transmitted light as well as the optical retardation of said transmitted light on the azimuth of the liquid crystal sample with respect to the polarization of the incident light is measured, by rotating an analyzer placed behind said liquid crystal sample.

4. An equipment of measuring a liquid crystal pretilt angle;

comprising;

a light source;

a polarizer which polarizes the emitted light from said light source;

a holder which holds a liquid crystal sample as an object of the measurement;

a mechanism to rotate said holder within plane;

a means for measuring, with the light having passed through said liquid crystal sample, the amplitude ratio of said transmitted light as well as the optical retardation of said transmitted light; and

a means for determining a liquid crystal pretilt angle from said measured polarization.