Method and apparatus for multi color display
First Claim
1. A field sequential color display system comprising:
- (a) a source of light of at least two different wavelengths;
(b) light polarizing means in optical communication with said source, including a color selective polarizing filter having first and second substantially orthogonally oriented absorption axes, the first absorption axis passing linearly polarized light of a first color and the second absorption axis passing linearly polarized light of a second color;
(c) circular polarizing means including a quarter wave plate having a slow axis rotationally displaced by 45°
from one of said absorption axes in optical communication with said light polarizing means for selectively transmitting light of a color determined by the amount by which the light emitted by said source is optically retarded;
(d) variable optical retarding means having first and second orthogonally oriented slow axes, one of said slow axes being aligned parallel to said quarter wave plate slow axis, disposed between said color selective polarizing filter and said circular polarizing means for retarding light applied to said circular polarizing means; and
(e) control means coupled to said variable optical retarding means for controlling the amount of optical retardation imposed by said retarding means upon light transmitted therethrough, whereby said retarding means are capable of at least first and second retardations resulting in the emission of light of at least first and second colors.
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Abstract
An apparatus and method for producing a color display from a substantially monochromatic source utilizes a liquid crystal cell combination together with a plechroic filter to differentially polarize the light components comprising the light emitted from the source. The liquid crystal cells are connected in push-pull fashion to individually retard light by one fourth of a wave as a function of the control signal applied to them. A fourth wave plate followed by a linear polarizer completes the optical combination. A signal at a first level applied to the cells causes transmission of one component color and blocks the other. A signal at a second level blocks the one component color and transmits the other. An intermediate level signal transmits both colors, resulting in a third, combination color.
86 Citations
15 Claims
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1. A field sequential color display system comprising:
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(a) a source of light of at least two different wavelengths; (b) light polarizing means in optical communication with said source, including a color selective polarizing filter having first and second substantially orthogonally oriented absorption axes, the first absorption axis passing linearly polarized light of a first color and the second absorption axis passing linearly polarized light of a second color; (c) circular polarizing means including a quarter wave plate having a slow axis rotationally displaced by 45°
from one of said absorption axes in optical communication with said light polarizing means for selectively transmitting light of a color determined by the amount by which the light emitted by said source is optically retarded;(d) variable optical retarding means having first and second orthogonally oriented slow axes, one of said slow axes being aligned parallel to said quarter wave plate slow axis, disposed between said color selective polarizing filter and said circular polarizing means for retarding light applied to said circular polarizing means; and (e) control means coupled to said variable optical retarding means for controlling the amount of optical retardation imposed by said retarding means upon light transmitted therethrough, whereby said retarding means are capable of at least first and second retardations resulting in the emission of light of at least first and second colors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of providing a field sequential color display in a high ambient light environment comprising the steps of:
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(a) generating a source of light having at least two different wavelength components; (b) polarizing the light thus generated using a color selective polarizing filter having first and second substantially orthogonally oriented absorption axes, the first absorption axis passing linearly polarized light of a first color and the second absorption axis passing linearly polarized light of a second color; (c) circularly polarizing said polarized light utilizing a polarizer having a slow axis rotationally displaced by 45°
from one of said absorption axes for selectively transmitting light of a color determined by the amount by which the light has been optically retarded;(d) selectively retarding light applied to said circular polarizing means utilizing variable optical retarding means, having at least one slow axis parallel to said polarizer slow axis, disposed between said color selective polarizing filter and the circular polarizer; and (e) controlling the amount of optical retardation by at least first and second retardations to result in the emission of light of at least first and second colors. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification