VEHICLE MIRROR WITH IMAGE DISPLAY FUNCTION

Abstract

According to the invention, there is provided a vehicle minor with an image display function including, in this order: an image display device; a circular polarization reflection layer; and a front surface plate made of glass or plastic, in which the circular polarization reflection layer includes a linear polarization reflection plate and a ¼ wavelength plate from the image display device side. The vehicle mirror with an image display function of the invention is capable of displaying a bright image.

Claims

1. A vehicle mirror with an image display function comprising, in this order: an image display device; a circular polarization reflection layer; and a front surface plate made of glass or plastic, wherein the circular polarization reflection layer includes a linear polarization reflection plate and a ¼ wavelength plate from the image display device side.

2. The vehicle mirror with an image display function according to claim 1, wherein the linear polarization reflection plate has a multi-layer structure.

3. The vehicle mirror with an image display function according to claim 2, wherein the multi-layer structure is a multi-layer structure in which resins having different types of birefringence are alternately laminated.

4. The vehicle mirror with an image display function according to claim 1, wherein the linear polarization reflection plate and the ¼ wavelength plate are directly adhered to each other through an adhesive layer.

5. The vehicle mirror with an image display function according to claim 3, wherein the linear polarization reflection plate and the ¼ wavelength plate are directly adhered to each other through an adhesive layer.

6. The vehicle mirror with an image display function according to claim 1, wherein the ¼ wavelength plate is a stretched film.

7. The vehicle mirror with an image display function according to claim 5, wherein the ¼ wavelength plate is a stretched film.

8. The vehicle mirror with an image display function according to claim 6, wherein the ¼ wavelength plate is a polycarbonate film.

9. The vehicle mirror with an image display function according to claim 7, wherein the ¼ wavelength plate is a polycarbonate film.

10. The vehicle mirror with an image display function according to claim 1, wherein the image display device and the circular polarization reflection layer are directly adhered to each other through an adhesive layer.

11. The vehicle mirror with an image display function according to claim 1, wherein the front surface plate is made of glass.

12. The vehicle mirror with an image display function according to claim 8, wherein the front surface plate is made of glass.

13. The vehicle mirror with an image display function according to claim 9, wherein the front surface plate is made of glass

14. The vehicle mirror with an image display function according to claim 1, which is a vehicle rearview mirror.

15. The vehicle mirror with an image display function according to claim 8, which is a vehicle rearview mirror.

16. The vehicle mirror with an image display function according to claim 9, which is a vehicle rearview mirror.

17. The vehicle mirror with an image display function according to claim 1, which has an outer frame.

18. The vehicle mirror with an image display function according to claim 15, which has an outer frame.

19. The vehicle mirror with an image display function according to claim 16, which has an outer frame.

20. The vehicle mirror with an image display function according to claim 17, which has an outer frame.

Description

EXAMPLES

[0098] Hereinafter, the invention will be described in more detail with reference to examples. The scope of the invention is not limited to the following examples.

Example 1

[0099] As a linear polarization reflection plate, a plate which was produced, based on a method described in JP1997-506837A (JP-H9-506837A), by adjusting thicknesses of respective layers of 2,6-polyethylene naphthalate (PEN) and 70-naphthalate/30-terephthalate copolyester (coPEN) such that the polarization control wavelength region was 380 nm to 720 nm was used. As a ¼ wavelength plate, PURE-ACE manufactured by TEIJIN LIMITED was used. A linear polarization reflection plate, a ¼ wavelength plate, and a front surface plate (glass plate) were adhered in this order to an adjacent layer using a UV-curable adhesive Exp. U12034-6 manufactured by DIC CORPORATION to produce a half mirror of the example. At this time, the slow axis of the ¼ wavelength plate was inclined by 45 degrees with respect to the transmission axis of the linear polarization reflection plate (polarization direction of light emission of the LCD).

Comparative Example 1

[0100] A half mirror was produced in the same manner as in Example 1, except that the ¼ wavelength plate was not bonded.

Comparative Example 2

[0101] A reflection layer was formed by uniformly vapor-depositing Al (metal aluminum) on a glass plate through a vacuum deposition method, and then a silicon oxide (SiO) was vapor-deposited as an inorganic barrier layer to produce a half mirror with visible light reflectivity of 65%.

[0102] The half mirror was disposed such that the circular polarization reflection plate was superposed on an image display surface of a liquid crystal display device (LCD) (manufactured by Apple Inc., iPad Air) (emission peak wavelength, 450 nm (B), 540 nm (G), 630 nm (R)) and the front surface plate was on the opposite side (nearest to an observer). At this time, the transmission axis of the linear polarization reflection plate was in the same direction as the transmission axis of the LCD (polarization direction of light emission of the LCD).

[0103] <Evaluation>

[0104] (Brightness) The front luminance during white display of the liquid crystal display device was measured using a measuring machine (EZ-Contrast 160D manufactured by ELDIM) as in the description in a paragraph [0180] in JP2009-93166A. “(The front luminance after the installation of the half mirror/the front luminance before the installation of the half mirror)×100%” was obtained for evaluation based on the following standards.

[0105] A: 100% or less and greater than 50%

[0106] B: 50% or less and greater than 40%

[0107] C: 40% or less

[0108] (Front Tint of Image, Possibility of Visual Recognition of Mirror-Reflected Image)

[0109] The visual evaluation was performed through polarized sunglasses. Regarding the evaluation of the front tint of an image, an example in which color balance and the like did not considerably change in comparison with an image when viewed without the polarized sunglasses was evaluated to be “good”, and a case where color balance and the like changed was evaluated to be “bad”.

[0110] Regarding the possibility of the visual recognition of a mirror-reflected image, an example in which even in a case where the image display surface of the mirror with an image display function was rotated about a normal line thereof with respect to the polarized sunglasses, a mirror-reflected image could be always visually recognized was evaluated to be “possible”, and an example in which there was a direction in which the mirror-reflected image could not be visually recognized was evaluated to be “not possible”.

[0111] The image of the LCD observed through the half mirror of the example was brighter than the image of the LCD observed through the half mirror of Comparative Example 2 including the metal-deposited mirror. In addition, in a non-image display (power-off) mode of the LCD, the mirror-reflected image observed in the half mirror of the example could be visually recognized in any direction even through polarized sunglasses, but in a case of the half mirror of Comparative Example 1, there was a direction in which the mirror-reflected image could not be visually recognized.

TABLE-US-00001 TABLE 1 Sunglasses Evaluation Possibility ¼ of Visual Wave- LCD Front Recognition of length Reflection Bright- Tint of Mirror-Reflected Plate Layer ness Image Image Example Used Linear A Good Possible 1 Polarization (85%) Reflection Plate Compar- None Linear A Good Not Possible ative Polarization (85%) Example Reflection 1 Plate Compar- None Metal- C Good Possible ative Deposited (38%) Example Film 2