Optical device

Patent metadata

Field	Value
Publication number	US-10180613-B2
Application number	US-201515301003-A
Country	US
Kind code	B2
Filing date	Mar 26, 2015
Priority date	Apr 2, 2014
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

An optical device (100) includes a first substrate (10), a second substrate (20) and an optical layer (30). The optical layer includes a medium (31) containing a liquid crystal material, and shape-anisotropic particles (32). At least one of the first substrate and the second substrate includes a film provided on the side of the optical layer, the film having a surface energy of 40 mJ/m2 or less, or having a contact angle with pure water of 75 degrees or greater or a contact angle with CH2l2 of 40 degrees or greater. Alternatively, at least one of the first substrate and the second substrate includes a vertical alignment film (15, 25) provided on the side of the optical layer.

First claim

The invention claimed is:

1. An optical device, comprising:
a first substrate and a second substrate provided to face each other; and
an optical layer provided between the first substrate and the second substrate;
wherein:
the optical layer includes a medium, and shape-anisotropic particles dispersed in the medium and having shape anisotropy;
the medium contains a liquid crystal material;
at least one of the first substrate and the second substrate includes a film provided on the side of the optical layer, the film having a surface energy of 40 mJ/m 2 or less, or having a contact angle with pure water of 75 degrees or greater, or a contact angle with CH 2 l 2 of 40 degrees or greater; and
a content Cf [wt. %] of the shape-anisotropic particles in the optical layer and a thickness D [μm] of the optical layer fulfill the relationship of 4≤(Cf·D)/10≤15.

2. An optical device, comprising:
a first substrate and a second substrate provided to face each other; and
an optical layer provided between the first substrate and the second substrate;
wherein:
the optical layer includes a medium, and shape-anisotropic particles dispersed in the medium and having shape anisotropy;
the medium contains a liquid crystal material;
at least one of the first substrate and the second substrate includes a vertical alignment film provided on the side of the optical layer, the vertical alignment film vertically aligning liquid crystal molecules contained in the liquid crystal material; and
a content Cf [wt. %] of the shape-anisotropic particles in the optical layer and a thickness D [μm] of the optical layer fulfill the relationship of 4≤(Cf·D)/10≤15.

3. The optical device according to claim 1 , wherein:
the first substrate includes a first electrode and a second electrode allowed to be supplied with different potentials from each other; and
the optical device is allowed to apply a transverse electric field to the optical layer.

4. The optical device according to claim 3 , wherein:
one of the first electrode and the second electrode is provided on the other of the first electrode and the second electrode with an insulating layer being held therebetween, and includes at least one slit; and
the other of the first electrode and the second electrode includes a portion facing the at least one slit.

5. The optical device according to claim 3 , wherein:
the first electrode and the second electrode have such shapes as to be geared with each other while having a predetermined gap therebetween;
the first substrate includes a further electrode located below the first electrode and the second electrode with an insulating layer being held between the further electrode and the first and second electrodes; and
the further electrode includes a portion facing the gap.

6. The optical device according to claim 3 , wherein:
at least one of the first electrode and the second electrode includes at least one branch; and
a width w of the at least one branch and a length l of each of the shape-anisotropic particles fulfill the relationship of w<l.

7. The optical device according to claim 3 , wherein:
the first electrode and the second electrode have such shapes as to be geared with each other while having a predetermined gap therebetween; and
a width g of the gap and a length I of each of the shape-anisotropic particles fulfill the relationship of g>1·(½).

8. The optical device according to claim 3 , wherein:
the second substrate includes a third electrode facing the first electrode and the second electrode; and
the optical device is allowed to apply a vertical electric field to the optical layer.

9. The optical device according to claim 8 , wherein the second substrate further includes a dielectric layer provided on the third electrode.

10. The optical device according to claim 9 , wherein a specific dielectric constant εr and a thickness t [μm] of the dielectric layer fulfill the relationship of εr·t>7.

11. The optical device according to claim 1 , wherein the liquid crystal material has positive dielectric anisotropy.

12. The optical device according to claim 11 , wherein the liquid crystal material has a dielectric anisotropy value Δε exceeding 15.

13. The optical device according to claim 1 , wherein a length I of each of the shape-anisotropic particles is 3 μm or greater and 10 μm or less.

14. The optical device according to claim 1 , wherein the shape-anisotropic particles are formed of a metal material having an insulating layer provided on a surface thereof.

15. The optical device according to claim 1 , wherein a thickness D of the optical layer is 10 μm or greater and 20 μm or less.

16. The optical device according to claim 1 , wherein the film or the vertical alignment film is not subjected to a rubbing treatment.

Assignees

• Sharp Kk

Inventors

• Moriwaki Hiroyuki

Classifications

• G02F1/133345

  Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence) · CPC title

• G02F1/134363

  for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS] · CPC title

• G02F2001/134381

  Physics · mapped topic

• G02F2001/13706

  Physics · mapped topic

• G02F1/1337

  Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers · CPC title