Matrix formulation for polymer dispersed liquid crystal displays in low power direct current (DC) electromagnetic field application
View Patent ↗A pre-polymer matrix formulation for a polymer dispersed liquid crystal (PDLC) display includes, in one aspect, a monofunctional monomer, a trifunctional oligomer, and a trifunctional monomer. A product, in another aspect, includes a PDLC display formulation comprising a polymer matrix having a plurality of liquid crystal (LC) domains dispersed therein, wherein the polymer matrix comprises a polymerized product of a monofunctional monomer, a trifunctional oligomer, and a trifunctional monomer, and a pair of electrodes having the PDLC display formulation positioned therebetween. The PDLC display formulation is characterized as having a substantially constant optical transparency during application of a low power direct current (DC) electromagnetic field between the electrodes for a predefined duration of time.
1. A product, comprising:
a polymer dispersed liquid crystal (PDLC) display formulation comprising a polymer matrix having a plurality of liquid crystal (LC) domains dispersed therein,
wherein the polymer matrix comprises a polymerized product of a monofunctional monomer, a trifunctional oligomer, and a trifunctional monomer;
a pair of electrodes having the PDLC display formulation positioned therebetween; and
a direct current electromagnetic field power circuit coupled to the pair of electrodes,
wherein the power circuit is configured to cause formation of a direct current electromagnetic field, the direct current electromagnetic field being at least 2.5 μW,
wherein the PDLC display formulation is opaque in the absence of application of a low power direct current electromagnetic field between the electrodes, and
wherein the PDLC display formulation is characterized as having a substantially constant optical transparency during application of the low power direct current electromagnetic field between the electrodes for a predefined duration of time.
2. A product as recited in claim 1 , wherein the PDLC display formulation is configured to have the substantially constant optical transparency during application of the low power direct current electromagnetic field in a range of at least 2.5 μW to less than 30 μW.
3. A product as recited in claim 1 , wherein the power circuit is configured to cause formation of a direct current at a voltage in a range of greater than 2.5 volts to less than 30 volts.
4. A product as recited in claim 1 , wherein the predefined duration of time is in a range of greater than 10 seconds to less than 3000 seconds.
5. A product as recited in claim 1 , wherein a concentration of the monofunctional monomer is in a range of 80 weight % to 90 weight % of a total weight of the polymer matrix.
6. A product as recited in claim 1 , wherein a concentration of the trifunctional oligomer is in a range of 10 weight % to 20 weight % of a total weight of the polymer matrix.
7. A product as recited in claim 1 , wherein a concentration of the trifunctional monomer is in a range of 1 weight % to 2 weight % of a total weight of the polymer matrix.
8. A product as recited in claim 1 , wherein the polymer matrix is configured to prevent interconnection of the LC domains with each other in the polymer matrix.
9. A product as recited in claim 1 , wherein the LC domains comprise a plurality of liquid crystal (LC) molecules.
10. A product as recited in claim 9 , wherein an average diameter of the LC domains is in a range of about 500 nanometers to about 2 microns.
11. A product as recited in claim 9 , wherein there is no orientation restriction of the LC molecules from the polymer matrix.
12. A product, comprising:
a polymer dispersed liquid crystal (PDLC) display formulation comprising a polymer matrix having a plurality of liquid crystal (LC) domains dispersed therein,
wherein the polymer matrix comprises a polymerized product of a monofunctional monomer, a trifunctional oligomer, and a trifunctional monomer;
a pair of electrodes having the PDLC display formulation positioned therebetween; and
a power circuit configured to cause formation of a low power direct current electromagnetic field of at least 2.5 μW,
wherein the PDLC display formulation is characterized as having a substantially constant optical transparency during application of the low power direct current electromagnetic field between the electrodes for a predefined duration of time wherein the predefined duration of time is greater than 10 seconds.
13. A product as recited in claim 12 , wherein the PDLC display has an opaque display with no application of power.
14. A product as recited in claim 13 , wherein the PDLC display formulation is configured to have the substantially constant optical transparency during application of the low power direct current electromagnetic field in a range of at least 2.5 μW to less than 30 μW.
15. A product, comprising:
a polymer dispersed liquid crystal (PDLC) display formulation comprising a polymer matrix having a plurality of liquid crystal (LC) domains dispersed therein,
wherein the polymer matrix comprises a polymerized product of a monofunctional monomer, a trifunctional oligomer, and a trifunctional monomer; and
a pair of electrodes having the PDLC display formulation positioned therebetween; and
a direct current electromagnetic field power circuit coupled to the pair of electrodes, wherein the power circuit is configured to cause formation of the direct current electromagnetic field, the direct current electromagnetic field being at least 2.5 μW,
wherein the PDLC display formulation is characterized as having a substantially constant optical transparency during application of a low power direct current electromagnetic field between the electrodes for a predefined duration of time.
16. A product as recited in claim 15 , wherein the PDLC display formulation has an opaque display with no application of power.
17. A product as recited in claim 1 , wherein the constant optical transparency corresponds to the PDLC display formulation configured to demonstrate a decrease in average rate of transmittance of less than 0.05% transmittance over 20 seconds of application of the low power direct current electromagnetic field.
18. A product as recited in claim 9 , wherein the polymer matrix is configured to have a refractive index that matches a refractive index of substantially aligned LC molecules, wherein the LC molecules are configured to be substantially aligned in response to presence of the low power direct current electromagnetic field.
19. A product as recited in claim 15 , wherein the polymer matrix is based on one of combinations of reactive functional groups selected from the group consisting of: acrylate-acrylate, acrylate-mercaptan, mercaptan-epoxide, and epoxide-epoxide.