Virtual image display apparatus, head-up display system, and transportation machine
A virtual image display apparatus that is configured to be mounted in a transportation machine and is configured such that P-polarized image display light is incident into a projection portion, a head-up display system, and the transportation machine provided therewith, the virtual image display apparatus and head-up display system including an image display device that emits projection image light, a diffractive reflective element having positive optical power, and a half-wave plate having a front retardation of 200 nm to 400 nm, in which the diffractive reflective element and the half-wave plate are provided on an optical path that guides the projection image light to the projection portion, in order from a side of the image display device.
1 . A virtual image display apparatus that is configured to be mounted in a transportation machine and is configured such that P-polarized image display light is incident into a projection portion, the virtual image display apparatus comprising:
an image display device that emits projection image light;
a diffractive reflective element having positive optical power; and
a half-wave plate having a front retardation of 200 nm to 400 nm,
wherein the diffractive reflective element and the half-wave plate are provided on an optical path that guides the projection image light to the projection portion, in order from a side of the image display device.
2 . The virtual image display apparatus according to claim 1 , further comprising:
a half-wave plate having a front retardation of 200 nm to 400 nm, which is provided between the diffractive reflective element having positive optical power and the image display device on the optical path.
3 . The virtual image display apparatus according to claim 1 ,
wherein the diffractive reflective element having positive optical power is a reflective type hologram element that is obtained by fixing a photosensitive material and that has a refractive index distribution.
4 . The virtual image display apparatus according to claim 1 ,
wherein the diffractive reflective element having positive optical power is a diffractive element that has an alignment film and a liquid crystal layer, that has a liquid crystal alignment pattern according to a periodic pattern of the alignment film, and that has a function of diffracting and reflecting incident light.
5 . The virtual image display apparatus according to claim 1 , further comprising:
a transmission type optical element having negative optical power, which is provided between the diffractive reflective element having positive optical power and the image display device on the optical path.
6 . The virtual image display apparatus according to claim 5 ,
wherein the transmission type optical element having negative optical power is a transmission type hologram element that is obtained by fixing a photosensitive material and that has a refractive index distribution.
7 . The virtual image display apparatus according to claim 5 ,
wherein the transmission type optical element having negative optical power is a diffractive element that has an alignment film and a liquid crystal layer, that has a liquid crystal alignment pattern according to a periodic pattern of the alignment film, and that has a function of diffracting and transmitting incident light.
8 . The virtual image display apparatus according to claim 5 ,
wherein the transmission type optical element having negative optical power is a lens that refracts the projection image light.
9 . The virtual image display apparatus according to claim 1 ,
wherein the image display device is a light field display.
10 . A head-up display system comprising:
a windshield glass that has a first glass plate, a P-polarized light reflection film, and a second glass plate; and
the virtual image display apparatus according to claim 1 .
11 . The head-up display system according to claim 10 ,
wherein the P-polarized light reflection film has a layer consisting of a cholesteric liquid crystal.
12 . The head-up display system according to claim 10 ,
wherein the P-polarized light reflection film has a layer formed by laminating an optically anisotropic layer and an optically isotropic layer.
13 . A transportation machine comprising:
the head-up display system according to claim 10 .