Image display mirror for a vehicle

• US 9,707,897 B2
• Filed: 02/01/2016
• Issued: 07/18/2017
• Est. Priority Date: 02/02/2015
• Status: Active Grant

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Kitamura, Yoshitsugu, Kimura, Keisuke, Takada, Katsunori, Kuramoto, Hiroki, Kameyama, Tadayuki
• Primary Examiner(s): Williams, Joseph L
• Application Number:
  US15/011,858
• Publication Number:
  US 20160221509A1
• Time in Patent Office: 533 Days
• CPC Class Codes: B60R 1/083 Anti-glare mirrors, e.g. "day-night" mirrors
• CPC Class Codes: B60R 1/084 using a removable filtering or hiding screen associated with windows or windscreens B60J3/00
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60R 2001/1215 with information displays
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/281 used for attenuating light intensity, e.g. comprising rotatable polarising elements
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08
• 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 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133567 on the back side

Abstract

An image display mirror for a vehicle includes a first polarizing plate arranged so as to be rotatable in a plane, a half mirror having a reflection axis and configured to reflect polarized light, and an image display apparatus in the stated order from a viewer side, in which: the first polarizing plate has a polarizer; a rotation of the first polarizing plate changes an angle of an absorption axis of the polarizer relative to a reflection axis of the half mirror when an image is not displayed on the image display apparatus and when the image is displayed thereon; when the image is not displayed, the absorption axis of the polarizer and the reflection axis of the half mirror are perpendicular to each other; and when the image is displayed, the absorption axis of the polarizer and the reflection axis of the half mirror are parallel to each other.

Claims

1. An image display mirror for a vehicle, comprising a first polarizing plate configured so as to be rotatable in a plane, a half mirror having a reflection axis and being configured to reflect polarized light, and an image display apparatus in the stated order from a viewer side, wherein:

the first polarizing plate has a polarizer;

the first polarizing plate is rotatably configured such that a rotation of the first polarizing plate changes an angle of an absorption axis of the polarizer relative to a reflection axis of the half mirror when an image is not displayed on the image display apparatus and when the image is displayed thereon;

the first polarizing plate is rotatably configured such that, when the image is not displayed, the absorption axis of the polarizer and the reflection axis of the half mirror are perpendicular to each other; and

the first polarizing plate is rotatably configured such that, when the image is displayed, the absorption axis of the polarizer and the reflection axis of the half mirror are parallel to each other.

2. The image display mirror for a vehicle according to claim 1, wherein the first polarizing plate is subjected to a low-reflection treatment.

3. The image display mirror for a vehicle according to claim 1, further comprising a λ

/4 plate on a viewer side of the first polarizing plate.

4. The image display mirror for a vehicle according to claim 1, wherein:

the image display apparatus comprises a liquid crystal display apparatus including a liquid crystal cell; and

the liquid crystal display apparatus is free of a polarizing plate on a viewer side of the liquid crystal cell.

5. A method by which a driver of a vehicle observes surroundings of the vehicle with the image display mirror for a vehicle of claim 1, the method comprising:

switching attached and removed states of the first polarizing plate when an image is displayed on the image display apparatus and when the image is not displayed thereon; and

arranging, when the image is displayed, the first polarizing plate between the half mirror and the driver of the vehicle.