Optical filter and process for producing the same

• US 7,025,908 B1
• Filed: 09/06/2000
• Issued: 04/11/2006
• Est. Priority Date: 09/16/1999
• Status: Expired due to Fees

• Current Assignee: Kureha Corporation
• Original Assignee: Kureha Corporation
• Inventors: Hayashi, Naoki, Katono, Hiroki, Koizumi, Tomoyoshi, Machida, Katsuichi, Syouji, Masuhiro
• Primary Examiner(s): Lipman, Bernard
• Application Number:
  US10/088,281
• Time in Patent Office: 2,043 Days
• Field of Search: 524/145, 524/781, 252/582, 523/136
• US Class Current: 252/582
• CPC Class Codes: C03C 17/28 with organic material C03C17/34, C03C17/44 take precedence
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence

Abstract

The optical filter of the present invention is provided with a near infrared light absorption layer that contains a component composed of copper ions and a phosphoric ester compound expressed by the following Formula (10), in which the phosphorus atom content in the near infrared light absorption layer is 0.4 to 1.3 mol per mole of copper ions, and the copper ion content in the near infrared light absorption layer is 2 to 60 wt %. Thus keeping the phosphorus atom and copper ion content within specific ranges results in good near infrared light absorption and in improved moisture resistance whereby devitrification caused by whitening is suppressed

Claims

1. An optical filter, comprising a near infrared light absorption layer containing the following component A and/or the following component B,

wherein the phosphorus atom content in the near infrared light absorption layer is 0.4 to 1.3 mol per mole of copper ions,

and the copper ion content in the near infrared light absorption layer is 2 to 60 wt %:

Component A;

a component composed of copper ions and a phosphoric ester compound expressed by the following Formula (1);

Component B;

a copper phosphate compound obtained by reaction of a copper compound with said phosphoric ester compound,

(in Formula (1), R is a group expressed by the following Formula (2), (3), (4), (5), (6), (7), (8), or (9), an alkyl group, an aryl group, an aralkyl group, or an alkenyl group, n is 1 or 2, and when n is 1, the R groups may be the same or different),

(in Formulas (2) to (9), R¹¹ to R¹⁷ are C₁ to C₂₀ alkyl groups or C₆ to C₂₀ aryl groups or aralkyl groups (where the one or more hydrogen atoms bonded to the carbon atoms that make up aromatic rings may be substituted with C₁ to C₆ alkyl groups or halogens), R²¹ to R²⁵ are hydrogen atoms or C₁ to C₄ alkyl groups (where R²³, R²⁴, and R²⁵ cannot all be hydrogen atoms), R³¹ and R³² are C₁ to C₆ alkylene groups, R⁴¹ is a C₁ to C₁₀ alkylene group, R⁵¹ and R⁵² are C₁ to C₂₀ alkyl groups, R⁶¹ is a hydrogen atom or methyl group, m is an integer from 1 to 6, k is an integer from 0 to 5, p is an integer from 2 to 97, and r is an integer from 1 to

     4).

2. The optical filter according to claim 1, wherein the phosphorus atom content in the near infrared light absorption layer is 0.8 to 1.3 mol per mole of copper ions.

3. The optical filter according to claim 1, wherein the phosphoric ester compound is such that R⁶¹ in Formula (9) is a methyl group, p in Formula (9) is 2 or 3, and r in Formula (9) is 1.

4. A method for manufacturing an optical filter having a near infrared light absorption layer containing the following component A and/or the following component B:

Component A;

a component composed of copper ions and a phosphoric ester compound expressed by the following Formula (1);

Component B;

a copper phosphate compound obtained by reaction of a copper compound with said phosphoric ester compound,

comprising the step of mixing or bringing into contact a phosphoric ester compound expressed by Formula (1), a copper salt, and water.

5. The method for manufacturing an optical filter according to claim 4, said step comprising:

mixing or bringing into contact a phosphoric ester compound expressed by Formula (1), a copper salt, and water such that the phosphorus atom content in the near infrared light absorption layer is 0.4 to 1.3 mol per mole of copper ions, and the copper ion content in the near infrared light absorption layer is 2 to 60 wt %.