Wave plate retarder
AssigneeSony Corporation
InventorsHiroshi Mori, Mikio Sugiki
Life of this patent
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Abstract
A wave plate retarder consists of a stacked plurality of doubly refracting or birefringent high molecular films laminated with a predetermined angle between their respective optical axes to establish a desired phase difference during transmission through the films of components of light polarized along orthogonal axes. The predetermined angle may be selected to provide a phase difference of 1/4 or 1/2 wavelength of light to thus produce a composite wave plate retarder which functions as a 1/4 or 1/2 wavelength plate regardless of the phase difference of components of light produced by transmission through a single film.
Claims2
A method of making a wave plate retarder comprising the steps of:
- placing a film of birefringent material having an optical axis with its surface normal to a linearly polarized beam of light;
- rotating said film about an axis parallel to said beam of light;
- measuring maximum and minimum values of a linearly polarized component of said beam of light after passing through said film during said rotating of the latter;
- determining a retardation phase angle from the following relationship:
- R=1/2(1+cos .GAMMA.)
- in which R is the ratio of said minimum value to said maximum value, and .GAMMA. is the retardation phase angle for said film;
- forming from said film two sheets having respective optical angles;
- and
- overlapping said two sheets with an angle C between their optical axes which is determined from the following relationship:
- R.sup.1 =(1/2 cos 2.GAMMA.-2 cos .GAMMA.+3/2) cos.sup.4 C+2(cos .GAMMA.-1) cos.sup.2 C+1
- in which R.sup.1 is 1/2 for a 1/4 wave plate retarder or R.sup.1 is 1 for a 1/2 wave plate retarder.
Dependencies are inferred from the claim text.