Heat reflection film

• US 4,556,599 A
• Filed: 10/23/1984
• Issued: 12/03/1985
• Est. Priority Date: 05/20/1982
• Status: Expired due to Term

• Current Assignee: Nippon Soken, Inc. (DENSO Corporation)
• Original Assignee: Nippon Soken, Inc. (DENSO Corporation)
• Inventors: Sato, Susumu, Hattori, Tadashi, Taguchi, Takashi, Ueno, Yoshiki
• Primary Examiner(s): Robinson, Ellis P.
• Application Number:
  US06/664,396
• Time in Patent Office: 406 Days
• Field of Search: 427/165, 427/169, 428/432, 428/426, 428/701, 428/699, 428/212, 428/216, 428/215, 350/164, 350/1.6, 350/166
• US Class Current: 428/216
• CPC Class Codes: G02B 5/282 reflecting for infrared and transparent for visible light, e.g. heat reflectors, laser protection
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick

Abstract

A heat-reflection film comprising:

a first layer formed on a base plate, the optical thickness of the first layer being approximately λ/8 or 3λ/8, in which λ is the designed wavelength;

a plurality of intermediate layers from a second layer to a (2n+2)th layer, in which n is a positive integral number, the optical thickness of each intermediate layer being λ/4; and

an uppermost (2n+3)th layer, the optical thickness of which is approximately λ/8,

wherein n_g <n₁ <n₂, in which n_g is the refractive index of the base plate, n₁ is the refractive index of the first layer, and n₂ is the refractive index of the second layer, the layers formed above the first layer being arranged in such a manner that high refractive index layers and low refractive index layers are alternately stacked, the second layer being arranged as a high refractive index layer.

Claims

1. A heat-reflection film comprising:

a first layer formed on a base plate which is transparent for visible rays, the optical thickness of said first layer being approximately λ

/8 or 3λ

/8, in which λ

is a designed wavelength;

a plurality of intermediate layers from a second layer to a (2n+2)th layer, in which n is a positive integral number, the optical thickness of each intermediate layer being λ

/4;

an uppermost (2n+3)th layer, the optical thickness of which is approximately λ

/8,

wherein n_g <

n₁ <

n₂, in which n_g is the refractive index of said base plate, n₁ is the refractive index of said first layer, and n₂ is the refractive index of said second layer, the layers formed above said first layer being arranged in such a manner that high refractive index layers and low refractive index layers are alternately stacked, said second layer being arranged as a high refractive index layer;

said heat-reflection film including said layers and said base plate being constructed and arranged so as to have a reflection ratio for visible rays which is smaller than the reflection ratio for visible rays of said base plate; and

said heat-reflection film including said layers and said base plate being constructed and arranged so as to have a reflection ratio for infrared rays which is greater than the reflection ratio for infrared rays of said base plate.

2. A heat-reflection film as set forth in claim 1, in which each of said high refractive index layers is formed from material selected from ZrO₂, TiO₂, and CeO₂ and in which each of said low refractive index layers in formed from material selected from MgF₂, SiO₂, Na₃ AlF₃, and CeF₄.

3. A heat-reflection film as set forth in claim 1, in which n=2 so that five intermediate layers are stacked between said first layer and said uppermost layer.

4. A heat-reflection film as set forth in claim 1, in which said first layer is formed from material selected from CeF₃, Al₂ O₃, SnO₂, PbF₃, NdF₃, Pr₆ O₁₁, and In₂ O₃ and a combination thereof.

5. A heat-reflection film as set forth in claim 1, in which said first layer is formed from a mixture of ZrO₂ and MgF₂.

6. A heat-reflection film as set forth in claim 1, in which said first layer comprises electrically conductive and optically transparent film.

7. A heat-reflection film as set forth in claim 1, in which the refractive index of said uppermost layer is the same as or less than that of said low refractive index layer.