Interferometric modulator displays with reduced color sensitivity
First Claim
1. A method of selecting a distance between two reflective surfaces for one or more interferometric modulators for use in a display so that the combination of interferometric modulators of the display reflect a target color, the two reflective surfaces defining an optical cavity of the interferometric modulator, the method comprising:
- for each of one or more interferometric modulators, determining a first distance between the two reflective surfaces of the interferometric modulator, wherein the determined first distance is the distance between the two reflective surfaces at which a rate of change of a color reflected from the interferometric modulator as a function of the distance between the two reflective surfaces is a local minimum;
determining a color of light that would be reflected from the display when the distance between the two reflective surfaces are at the determined first distances for each of the interferometric modulators of the display; and
for each of one or more of the interferometric modulators, varying the distance between the two reflective surfaces away from the first distance to determine a second distance between the two reflective surfaces, wherein the color of light that would be reflected from the display when the two reflective surfaces of the interferometric modulators are set to the second distances is closer to the target color than when the two reflective surfaces of the interferometric modulators are set to the first distances.
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Abstract
Methods are described for selecting reflective layer distances in an interferometric modulator display that result in reduced color sensitivity to temperature and process variation. Colors are selected for interferometric modulator subpixels that correspond to a minimum in the rate that the colors change with respect to reflective layer distance. In some cases, colors are selected that deviate from the minimums in order to obtain a desired target color (e.g., a desired white point).
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Citations
43 Claims
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1. A method of selecting a distance between two reflective surfaces for one or more interferometric modulators for use in a display so that the combination of interferometric modulators of the display reflect a target color, the two reflective surfaces defining an optical cavity of the interferometric modulator, the method comprising:
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for each of one or more interferometric modulators, determining a first distance between the two reflective surfaces of the interferometric modulator, wherein the determined first distance is the distance between the two reflective surfaces at which a rate of change of a color reflected from the interferometric modulator as a function of the distance between the two reflective surfaces is a local minimum; determining a color of light that would be reflected from the display when the distance between the two reflective surfaces are at the determined first distances for each of the interferometric modulators of the display; and for each of one or more of the interferometric modulators, varying the distance between the two reflective surfaces away from the first distance to determine a second distance between the two reflective surfaces, wherein the color of light that would be reflected from the display when the two reflective surfaces of the interferometric modulators are set to the second distances is closer to the target color than when the two reflective surfaces of the interferometric modulators are set to the first distances. - View Dependent Claims (2, 3)
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4. A method of selecting colors for an interferometric modulator display, the method comprising:
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determining a color for at least one interferometric modulator for which the rate of change of the color with respect to distance between reflective surfaces in the interferometric modulator is a local minimum, wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances; andvarying the color so that a certain color reflected from the display is substantially close to a desired target color, wherein determining the color difference in u′
-v′
color space comprises determining the value √
{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}, and wherein u1′ and
v1′
are color parameters corresponding to the first reflective surface distance and u2′ and
v2′
are color parameters corresponding to the second reflective surface distance. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of selecting colors for an interferometric modulator display, the method comprising:
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determining a color for at least one interferometric modulator for which the rate of change of the color with respect to distance between reflective surfaces in the interferometric modulator is a local minimum, wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances; andvarying the color so that a certain color reflected from the display is substantially close to a desired target color, wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances, and wherein the two different reflective surface distances are about 1 nm apart.
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16. A method of selecting colors for an interferometric modulator display, the method comprising:
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determining a color for at least one interferometric modulator for which the rate of change of the color with respect to distance between reflective surfaces in the interferometric modulator is a local minimum, wherein determining the color comprises modeling the optical response from the interferometric modulator, and wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances; andvarying the color so that a certain color reflected from the display is substantially close to a desired target color, wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances,wherein the optical model includes one or more thickness of a material layer in the interferometric modulator, one or more refractive index of a material layer in the interferometric modulator, and one or more extinction coefficient of a material layer in the interferometric modulator.
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17. A computer-readable medium comprising computer-executable instructions for performing the method comprising:
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determining a color for at least one interferometric modulator for which the rate of change of the color with respect to distance between reflective surfaces in the interferometric modulator is a local minimum, wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances; andvarying the color so that a certain color reflected from the display is substantially close to a desired target color;
wherein determining the color difference in u′
-v′
color space comprises determining the value √
{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}, and wherein u1′ and
v1′
are color parameters corresponding to the first reflective surface distance and u2′ and
v2′
are color parameters corresponding to the second reflective surface distance. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method of manufacturing an interferometric modulator display, each interferometric modulator including two reflective surfaces defining an optical cavity, the method comprising:
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selecting distances between reflective surfaces in each interferometric modulator of the display so that a combination of interferometric modulators of the display reflect a target color, wherein the distances are selected by; for each of one or more interferometric modulators, determining a first distance between two reflective surfaces of the interferometric modulator, wherein the determined first distance is the distance between the two reflective surfaces at which a rate of change of a color reflected from the interferometric modulator as a function of the distance between the two reflective surfaces is a local minimum; determining a color of light that would be reflected from the display when the distance between the two reflective surfaces are at the determined first distances for each of the interferometric modulators of the display; for each of one or more of the interferometric modulators, varying the distance between the two reflective surfaces away from the first distance to determine a second distance between the two reflective surfaces, wherein the color of light that would be reflected from the display when the two reflective surfaces of the interferometric modulators are set to the second distances is closer to the desired target color than when the two reflective surfaces of the interferometric modulators are set to the first distances; and manufacturing an array of interferometric modulators having the selected distances.
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25. An interferometric modulator display, comprising at least one interferometric modulator having a bright state color within 0.04 units in u′
- -v′
color space of a color at which the rate of change of color with respect to distance between reflective surfaces in the interferometric modulator is a local minimum,wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different reflective surface distances, andwherein determining the color difference in u′
-v′
color space comprises determining the value √
{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}, and wherein u1′ and
v1′
are color parameters corresponding to the first reflective surface distance and u2′ and
v2′
are color parameters corresponding to the second reflective surface distance. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
- -v′
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36. A display, comprising:
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first means for reflecting light; and second means for reflecting light, wherein the distance between the first and second means is such that light interferometrically reflected from the first and second means has a color within 0.04 units in u′
-v′
color space of a color at which the rate of change of color with respect to distance between the first and second means is a local minimum,wherein determining the rate of change of color with respect to distance comprises determining the color difference in u′
-v′
color space between colors generated for two different distances between the first light reflecting means and the second light reflecting means, andwherein determining the color difference in u′
-v′
color space comprises determining the value √
{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}{square root over ((u2′
−
u1′
)2+(v2′
−
v1′
)2)}, and wherein u1′ and
v1′
are color parameters corresponding to the light reflected when the first and second light reflecting means are separated by the first distance and u2′ and
v2′
are color parameters corresponding to the light reflected when the first and second light reflecting means are separated by the second distance. - View Dependent Claims (37, 38, 39)
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40. An interferometric modulator display, comprising at least one interferometric modulator having a bright state color that varies less than about 0.03 units in u′
- -v′
color space over a 20°
C. temperature change, wherein the varying units of the bright state color is determined by a bright state color difference in u′
-v′
color space between colors generated for two different temperatures using the value √
(u′
2−
u′
1)2+(v′
2−
v′
1)2; and
wherein u′
1 and v′
1 are color parameters corresponding to the light reflected from the interferometric modulator at a first temperature and u′
2 and v′
2 are color parameters corresponding to the light reflected from the interferometric modulator are at a second temperature. - View Dependent Claims (41, 42, 43)
- -v′
Specification