Phase-difference element having birefringent film containing TiO2 and Ta2O5

Patent metadata

Field	Value
Publication number	US-9376744-B2
Application number	US-201213468388-A
Country	US
Kind code	B2
Filing date	May 10, 2012
Priority date	May 16, 2011
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

A phase difference element has a transparent substrate and a birefringent film with tantalum oxide and titanium oxide obliquely deposited on one surface of the transparent substrate. The birefringent film has a first photorefractive film and a second photorefractive film laminated to each other and having different oblique deposition directions. The ratio of titanium atoms to the total of titanium atoms and tantalum atoms in the birefringent film is 4.0 atomic % or higher to 30 atomic % or lower.

First claim

The invention claimed is:

1. A phase difference element, comprising a transparent substrate and a birefringent film in which tantalum oxide and titanium oxide are obliquely deposited on one surface of the transparent substrate,
wherein:
the birefringent film comprises a plurality of first photorefractive films and second photorefractive films that are directly and alternately laminated to each other and have different oblique deposition directions,
a ratio of titanium atoms to a total of titanium atoms and tantalum atoms in the birefringent film is 4.0 atomic % or higher and 30 atomic % or lower,
the transparent substrate comprises a plurality of parallel grooves formed in the surface on which the tantalum oxide and titanium oxide are obliquely deposited,
each of the first photorefractive films and each of the second photorefractive films comprises tantalum oxide and titanium oxide, and
each of the first photorefractive films is a single layer and each of the second photoreflective films is a single layer.

2. A phase difference element, comprising a transparent substrate and a birefringent film, the birefringent film including a plurality of first photorefractive films and second photorefractive films that are directly and alternately laminated to each other, each of the plurality of first photorefractive films being grown on the transparent substrate or one of the second photorefractive films along a first oblique direction from which a material vapor enters, the material vapor being emitted from a deposition material containing Ta 2 O 5 and TiO 2 and going straight ahead, and each of the plurality of second photorefractive films being grown on one of the first photorefractive films along a second oblique direction from which the material vapor enters, the second oblique direction being different from the first oblique direction,
wherein:
each of the first photorefractive films and each of the second photorefractive films comprises tantalum oxide and titanium oxide,
a ratio of Ti to a total of Ta and Ti, (Ti/(Ta+Ti)), of the first and the second photorefractive films is 4.0 atomic % or higher and 30 atomic % or lower,
the transparent substrate comprises a plurality of parallel grooves formed in the surface on which the tantalum oxide and titanium oxide are obliquely deposited, and
each of the first photoreflective films is a single layer and each of the second photoreflective films is a single layer.

3. A method for producing a phase difference element, comprising:
obliquely depositing Ta 2 O 5 and TiO 2 on a transparent substrate in a first oblique direction to form a first photorefractive film, and
obliquely depositing Ta 2 O 5 and TiO 2 on the first photorefractive film in a second oblique direction to form a second photorefractive film, the second oblique direction being different from the first oblique direction, and
forming a birefringent film comprising a plurality of first photorefractive films and second photorefractive films that are directly and alternately laminated to each other,
wherein:
Ta 2 O 5 and TiO 2 are obliquely deposited such that a ratio of titanium atoms to a total of titanium atoms and tantalum atoms in the birefringent film is 4.0 atomic % or higher to 30 atomic % or lower,
the transparent substrate comprises a plurality of parallel grooves formed in the surface on which the Ta 2 O 5 and TiO 2 are obliquely deposited,
each of the first photorefractive films and each of the second photorefractive films comprises tantalum oxide and titanium oxide, and
each of the first photorefractive films is a single layer and each of the second photorefractive films is a single layer.

4. The phase difference element according to claim 1 , wherein the ratio of titanium atoms to the total of titanium atoms and tantalum atoms in the birefringent film is 10 atomic % or higher and 20 atomic % or lower.

5. The phase difference element according to claim 1 , wherein the transparent substrate is a quartz glass substrate.

6. The phase difference element according to claim 1 , wherein a component parallel to a front surface of the transparent substrate in the first oblique direction and a component parallel to the front surface of the transparent substrate in the second oblique direction are directed to respective directions opposite to each other.

7. A display device comprising: the phase difference element according to claim 1 ; and a liquid crystal, wherein light passing through the liquid crystal and the phase difference element is emitted outside.

8. The phase difference element according to claim 2 , wherein the ratio of Ti to the total of Ta and Ti, (Ti/(Ta+Ti)), of the first and the second photorefractive films is 10 atomic % or higher and 20 atomic % or lower.

9. The method for producing a phase difference element according to claim 3 , comprising, after forming the birefringent film, performing an annealing treatment.

Assignees

• Koike Nobuyuki
• Dexerials Corp

Inventors

• Koike Nobuyuki

Classifications

• G02F1/0126

  Opto-optical modulation, i.e. control of one light beam by another light beam, not otherwise provided for in this subclass · CPC title

• G02F2202/13

  photorefractive · CPC title

• C23C14/083 Primary

  of refractory metals or yttrium · CPC title

• C23C14/5886

  Mechanical treatment (involving removal of material C23C14/588) · CPC title

• G02B5/3083 Primary

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title