Multicomponent optical body

• US 6,667,095 B2
• Filed: 01/25/2001
• Issued: 12/23/2003
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wheatley, John A., Weber, Michael F., Nevitt, Timothy J., Merrill, William W.
• Primary Examiner(s): Chen, Vivian
• Application Number:
  US09/769,971
• Publication Number:
  US 20010009714A1
• Time in Patent Office: 1,062 Days
• Field of Search: 428/212, 428/480, 428/213, 428/426, 359/483, 359/485, 359/487, 359/494, 359/500, 359/577, 359/580, 359/584, 359/586, 359/350, 359/352, 359/359, 359/838, 359/839
• US Class Current: 428/212
• CPC Class Codes: G02B 5/282 reflecting for infrared and transparent for visible light, e.g. heat reflectors, laser protection
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

Multilayer polymeric films and other optical bodies are provided. The films, which have at least three layers of different composition in the optical repeating unit, reflect light in a first portion of the spectrum while transmitting light in a second portion of the spectrum, exhibit improved reflectivities at oblique angles, and can be designed to suppress one or more higher order harmonics of the main reflection band.

Claims

1. An infrared reflecting mirror comprising a first reflective film that reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum, wherein

the first reflective film comprises a multilayer film comprising an optical repeating unit that comprises polymeric layers A, B and C arranged in an order ABC,

the polymeric layer A having refractive indices n_x^a and n_y^a along in-plane axes x and y respectively,

the polymeric layer B having refractive indices n_x^b and n_y^b along in-plane axes x and y respectively,

the polymeric layer C having refractive indices n_x^c and n_y^c along in-plane axes x and y respectively,

polymeric layers A, B and C having a refractive index n_z^a, n_z^b and n_z^c respectively along a transverse axis z perpendicular to the in-plane axes,

wherein n_x^a>

n_x^b>

n_x^c, or n_y^a>

n_y^b>

n_y^c, or both n_x^a>

n_x^b>

n_x^c and n_y^a>

n_y^b>

n_yc, and

wherein at least one of the differences n_z^a−

n_z^b or n_z^b−

n_z^c is less than 0 or both the differences are substantially equal to 0.

2. An infrared reflecting mirror according to claim 1 further comprising a second reflective film that reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum, wherein the first and second reflective films are uniaxially oriented and arranged such that their axes of orientation are rotated 90°

to one another, and wherein

the second reflective film comprises a multilayer film comprising an optical repeating unit that comprises polymeric layers A, B and C arranged in an order ABC,

the polymeric layer A having refractive indices n_x^a and n_y^a along in-plane axes x and y respectively,

the polymeric layer B having refractive indices n_x^b and n_y^b along in-plane axes x and y respectively,

the polymeric layer C having refractive indices n_x^c and n_y^c along in-plane axes x and y respectively,

polymeric layers A, B and C having a refractive index n_z^a, n_z^b and n_z^c respectively along a transverse axis z perpendicular to the in-plane axes,

wherein n_x^a>

n_x^b>

n_x^c, or n_y^a>

n_y^b>

n_y^c, or both n_x^a>

n_x^b>

n_x^c and n_y^a>

n_y^b>

n_y^c, and

wherein at least one of the differences n_z^a−

n_z^b or n_z^b is less than 0 or both the differences are substantially equal to 0.

3. A method of reflecting infrared light comprising the steps of providing an infrared reflecting mirror according to claim 1 and allowing at least a portion of incident infrared light to reflect from said reflective film.

4. The method of claim 3, wherein at least 50 percent of incident infrared light having a wavelength of between 750 nm and 1600 nm is reflected.

5. A material comprising on a support a reflective film that reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum, wherein

the reflective film comprises a multilayer film comprising an optical repeating unit that comprises polymeric layers A, B and C arranged in an order ABC,

the polymeric layer A having refractive indices n_x^a and n_y^a along in-plane axes x and y respectively,

the polymeric layer B having refractive indices n_x^b and n_y^b along in-plane axes x and y respectively,

the polymeric layer C having refractive indices n_x^c and n_y^c along in-plane axes x and y respectively,

polymeric layers A, B and C having a refractive index n_z^a, n_z^b and n_z^c respectively along a transverse axis z perpendicular to the in-plane axes,

wherein n_x^a>

n_x^b>

n_x^c, or n_y^a>

n_y^b>

n_y^c, or both n_x^a>

n_x^b>

n_x^c and n_y^a>

n_y^b>

n_y^c, and

wherein at least one of the differences n_z^a−

n_z^b or n_z^b−

n_z^c is less than 0 or both the differences are substantially equal to 0.

6. The material of claim 5, wherein the support is transparent to visible light.

7. The material claim 5, wherein the support is glass or a plastic film.

8. A method of reflecting infrared light comprising the steps of providing a reflective film that reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum and allowing at least a portion of incident infrared light to reflect from the reflective film, wherein

the reflective film comprises a multilayer film comprising an optical repeating unit that comprises polymeric layers A, B and C arranged in an order ABC,

the polymeric layer A having refractive indices n_x^a and n_y^a along in-plane axes x and y respectively,

the polymeric layer B having refractive indices n_x^b and n_y^b along in-plane axes x and y respectively,

the polymeric layer C having refractive indices n_x^c and n_y^c along in-plane axes x and y respectively,

polymeric layers A, B and C having a refractive index n_z^a, n_z^b and n_z^c respectively along a transverse axis z perpendicular to the in-plane axes,

wherein n_x^a>

n_x^b>

n_x^c, or n_y^a>

n_y^b>

n_y^c, or both n_x^a>

n_x^b>

n_x^c and n_y^a>

n_y^b>

n_y^c, and

wherein at least one of the differences n_z^a−

n_z^b or n_z^b−

n_z^c is less than 0 or both the differences are substantially equal to 0.

9. The method of claim 8, wherein at least 50 percent of incident infrared light having a wavelength between 750 nm and 1600 nm is reflected.

10. An optical body comprising:

a first polymeric layer A;

a second polymeric layer B; and

a third polymeric layer C;

wherein A, B, and C, are arranged in the sequence ABC, where B is contiguous to A and C;

wherein

A has refractive indices n_x^A, n_y^A, and n_z^A for light polarized along mutually orthogonal axes x, y, and z, respectively,

B has refractive indices n_x^B, n_y^B, and n_z^B for light polarized along axes x, y, and z, respectively, and

C has refractive indices n_x^C, n_y^C, and n_z^C for light polarized along axes x, y, and z, respectively;

wherein axis z is orthogonal to layer B; and

wherein the indices of refraction of layers A, B, and C are in accordance with Formula I and at least one of Formulas II and III;

11. The optical body of claim 10, wherein the optical body comprises a plurality of repeating units having the layer sequence ABC.

12. The optical body of claim 10, wherein the optical body comprises a plurality of repeating units having the layer sequence ABCB.

13. The optical body of claim 11,

wherein A, B, and C have optical thickness ratios f_x^a, f_x^b, and f_x^c, respectively, along in-plane axis x, and f_y^a, f_y^b, and f_y^c, respectively, along in-plane axis y, and

wherein f_x^a=⅓

, f_x^b=⅙

, f_x^c=⅓

, and n_x^b=(n_x^an_x^c)^1/2 or

wherein f_y^a=⅓

, f_y^b=⅙

, f_y^c=⅓

, and n_y^b =(n_y^an_y^c)^1/2.

14. The optical body of claim 11,

wherein A, B, and C have optical thickness ratios f_x^a, f_x^b, and f_x^c, respectively, along in-plane axis x, and f_y^a, f_y^b, and f_y^c, respectively, along in-plane axis y, and

wherein f_x^a=⅓

, f_x^b=⅙

, f_x^c=⅓

, and n_x^b=(n_x^an_x^c)^1/2 and

wherein f_y^a=⅓

, f_y^b=⅙

, f_y^c=⅓

, and n_y^b=(n_y^an_y^c)^1/2.