Reflective polarizer having improved properties and optical display with improved reflective polarizer

• US 6,543,153 B1
• Filed: 11/30/1999
• Issued: 04/08/2003
• Est. Priority Date: 12/21/1993
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Cobb, Sanford Jr., Jonza, James M., Wortman, David L., Weber, Michael F., Ouderkirk, Andrew J., Stover, Carl A., Benson, Olester Jr.
• Primary Examiner(s): Parker, Kenneth
• Application Number:
  US09/451,346
• Time in Patent Office: 1,225 Days
• Field of Search: 347/96, 347/97, 347/98, 347/105, 359/498, 359/499
• US Class Current: 34/96
• CPC Class Codes: A47J 36/28 Warming devices generating the heat by exothermic reactions, e.g. heat released by the contact of unslaked lime with water
• CPC Class Codes: B29C 55/023 using multilayered plates or sheets
• CPC Class Codes: B29D 11/00 Producing optical elements, e.g. lenses or prisms grinding or polishing of optical elements B24B; constructional form of optical elements G02B; optical parts of spectacles G02C7/00
• CPC Class Codes: B29K 2995/003 Reflective
• CPC Class Codes: B29K 2995/0034 Polarising
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/023 Optical properties
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02B 5/3083 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 Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one

Abstract

A multiple layer reflective polarizer 12 is described. This element is placed between and optical cavity 24 and an LCD module 16 to form an optical display. The reflective polarizer reflects some light into the optical cavity 24 where it is randomized and may ultimately emerge with the correct polarization to be transmitted out of the display.

Claims

1. A display comprising:

a display module;

an optical cavity; and

a reflective polarizer between the display module and the optical cavity that transmits light of a first polarization and reflects light of a second polarization, wherein the reflective polarizer transmits at least 70% of visible light of the first polarization incident normal to a surface of the reflective polarizer, transmits less than 25% of visible light of the second polarization incident normal to the surface of the reflective polarizer and has less than 8% C_RMS color for visible light at an angle of 45 degrees from normal to the surface of the reflective polarizer.

2. A display as recited in claim 1, further comprising an absorbing polarizer disposed between the display module and the reflective polarizer.

3. A display as recited in claim 1, wherein the visible light comprises light in a wavelength range of 400nm to 700nm.

4. A display as recited in claim 1, wherein the display module comprises an LCD display panel.

5. A display as recited in claim 4, wherein the reflective polarizer is adhered to the LCD panel.

6. A display as recited in claim 2, wherein the reflective polarizer is adhered to the display module.

7. A reflective polarizer that, when illuminated with visible light, transmits light of a first polarization and reflects light of a second polarization, wherein the reflective polarizer transmits at least 70% of the visible light of the first polarization incident normal to a surface of the reflective polarizer, transmits less than 25% of the visible light of the second polarization incident normal to the surface of the reflective polarizer and has less than 8% C_RMS color for the visible light at an angle of 45 degrees from normal to the surface of the reflective polarizer.

8. A display comprising:

a display module;

an optical cavity; and

a polymeric reflective polarizing film disposed between the display module and the optical cavity that transmits light of a first polarization and reflects light of a second polarization, wherein the reflective polarizing film transmits at least 70% of visible light of the first polarization incident normal to a surface of the reflective polarizer, transmits less than 25% of visible light of the second polarization incident normal to the surface of the reflective polarizer and has less than 8% RMS color for visible light at an angle of 45 degrees from normal to the surface of the reflective polarizer.

9. A display comprising:

a display module;

an optical cavity; and

a reflective polarizer, that substantially transmits light of a first polarization and substantially reflects light of a second polarization, disposed in a plane between the display module and the optical cavity, wherein the reflective polarizer transmits at least 85% of visible light of the first polarization incident normal to the plane of the reflective polarizer, transmits less than 25% of visible light of the second polarization incident normal to the plane of the reflective polarizer and has less than 8% C_RMS color for visible light at an angle of at least 60 degrees from normal to the plane of the reflective polarizer, where C_RMS color is defined by the relationship;

$C_{\mathrm{RMS}}=\frac{{\int <br><br>}_{{\mathrm{\lambda <br><br>}}_1}^{{\mathrm{\lambda <br><br>}}_2}<br><br>{\left({\left(T-\stackrel{\_}{T}\right)}^2\right)}^{1/2}<br><br>\text{\hspace{1em}<br><br>}<br><br><br><br>\mathrm{\lambda <br><br>}}{\stackrel{\_}{T}<br><br>\left({\mathrm{\lambda <br><br>}}_2-{\mathrm{\lambda <br><br>}}_1\right)},$

where λ

₁ to λ

₂ define a bandwidth for visible light, T is the transmissivity of the first polarization as a function of wavelength and {overscore (T)} is the average transmissivity of the first polarization for visible light.

10. A display comprising:

a light source having a reflective optical cavity configured to randomize direction and polarization of light reflected by the optical cavity;

a display module;

a geometric structured surface material disposed between the light source and the display module, the structure surface material redirecting a portion of light incident on the structured surface material from an incidence angle to a transmission angle, the transmission angle being less than the incidence angle measured from an axis normal to the plane of the display module;

a reflective polarizer disposed between the light source and the display module, the reflective polarizer having a birefringent material arranged such that light of a first polarization is substantially reflected toward the optical cavity while light of a second polarization is substantially transmitted through the reflective polarizer toward the display; and

an absorbing polarizer disposed between the reflective polarizer and the display module.

11. A display comprising:

a light source having a reflective optical cavity configured to randomize direction and polarization of light reflected by the optical cavity;

a display module;

a geometric structured surface material disposed between the light source and the display module, the structure surface material redirecting a portion of light incident on the structured surface material from an incidence angle to a transmission angle, the transmission angle being less than the incidence angle measured from an axis normal to the plane of the display module; and

a reflective polarizer disposed between the light source and the display module, the reflective polarizer having a birefringent material arranged such that light of a first polarization encounters changes in refractive indices, as the light of the first polarization propagates in the reflective polarizer, sufficient to reflect the light of the first polarization toward the optical cavity, while light of a second polarization is substantially transmitted through the reflective polarizer toward the display.