Synthetic resin half-mirror

• US 4,979,802 A
• Filed: 02/28/1990
• Issued: 12/25/1990
• Est. Priority Date: 06/04/1987
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Ichikawa, Hajime
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Lerner, Martin
• Application Number:
  US07/488,535
• Time in Patent Office: 300 Days
• Field of Search: 428/333, 350/164, 350/165, 350/166, 350/642
• US Class Current: 359/584
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 5/0833 comprising inorganic materials only
• CPC Class Codes: Y10T 428/261 In terms of molecular thickness or light wave length

Abstract

A synthetic resin half-mirror comprises a synthetic resin substrate, a first SiO film layer deposited thereon, and further at least two SiO₂ layers and CeO₂ film layers alternately deposited thereon and satisfies a spectral reflectance at incident angle of 45° of not less than 40% as an optical property.

Claims

1. A synthetic resin half-mirror comprising a substrate made from a synthetic resin, a first film layer laminated thereon and made from SiO and at least four film layers laminated on the first film layer and alternately made from SiO₂ and CeO₂.

2. The synthetic resin half-mirror according to claim 1, wherein said first film layer of SiO has an optical thickness of nd=λ

/12˜

λ

/2 and adjoining film layer of SiO₂ has an optical thickness of nd=λ

/8˜

λ

/4.

3. A synthetic resin half-mirror comprising:

a substrate composed of synthetic resin;

a first film layer laminated on the substrate and composed of SiO; and

at least four film layers successively laminated on the first film layer and on one another, the at least four film layers being alternately composed of SiO₂ and CeO₂, the lowermost film layer which is laminated on the first film layer being composed of SiO₂ and the uppermost film layer being composed of CeO₂ and defining the incident-light surface of the half-mirror.

4. A synthetic resin half-mirror according to claim 3;

wherein the at least four film layers consist of four film layers.

5. A synthetic resin half-mirror according to claim 4;

wherein the first film layer composed of SiO has an optical thickness in the range nd=λ

/12-λ

/2, and the lowermost film layer composed of SiO₂ has an optical thickness in the range nd=λ

/8-λ

/4.

6. A synthetic resin half-mirror according to claim 5;

wherein the four film layers alternately composed of SiO₂ and CeO₂ each have an optical thickness nd=λ

/4.

7. A synthetic resin half-mirror according to claim 3;

wherein the at least four film layers consist of six film layers.

8. A synthetic resin half-mirror according to claim 7;

wherein the first film layer composed of SiO has an optical thickness in the range nd=λ

/12-λ

/2, and the lowermost film layer composed of SiO₂ has an optical thickness in the range nd=λ

/8-λ

/4.

9. A synthetic resin half-mirror according to claim 8;

wherein the six film layers alternately composed of SiO₂ and CeO₂ each have an optical thickness nd=λ

/4.

10. A synthetic resin half-mirror according to claim 3;

wherein the first film layer composed of SiO has an optical thickness in the range nd-32 λ

/12-λ

/2, and the lowermost film layer composed of SiO₂ has an optical thickness in the range nd=λ

/8-λ

/4.

11. A synthetic resin half-mirror according to claim 10;

wherein the at least four film layers alternately composed of SiO₂ and CeO₂ each have an optical thickness nd=λ

/4.

12. A synthetic resin half-mirror according to claim 3;

wherein the film layers exhibit a spectral reflectance of not less than 40% for light incident on the incident-light surface at an incident angle of 45°

.