Display Light Projection Optical Device

• US 20160327792A1
• Filed: 07/21/2016
• Published: 11/10/2016
• Est. Priority Date: 02/26/2014
• Status: Active Grant

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Matsushita, Junichi
• Granted Patent: US 10,095,028 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 2360/20 Optical features of instruments
• CPC Class Codes: B60K 2360/334 Projection means
• CPC Class Codes: B60K 35/00 Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
• CPC Class Codes: B60K 35/23 Head-up displays [HUD] optical aspects of head-up displays G02B27/01
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 3/08 with discontinuous faces, e.g. Fresnel lens diffractive Fresnel lenses G02B5/1876
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08

Abstract

There are provided a first optical member that is transparent and is formed in a thin plate shape; a Fresnel-shaped portion that is formed in a concentric form on one surface of the first optical member in the thickness direction; a half mirror layer that is formed on a surface of a Fresnel-shaped portion; a second optical member that is formed of a transparent filler for filling unevenness of a surface of the half mirror layer to form a flat surface; and a third optical member that has a transparent thin plate shape protecting an outside surface of the second optical member. A refractive index of the first optical member, a refractive index of the second optical member, and a refractive index of the third optical member are equal.

Claims

1. A display light projection optical device, having characteristics in which display light emitted from a display unit is reflected in a vicinity of one surface and is projected to a predetermined eye point, and in which external light incident on the other surface is transmitted in a thickness direction, the display light projection optical device comprising:

a first optical member that is transparent and is formed in a thin plate shape;

a Fresnel-shaped portion that is formed by a plurality of grooves which are concentric with each other on one surface of the first optical member in a thickness direction thereof;

a half mirror layer that is formed on a surface of a Fresnel-shaped portion;

a second optical member that is formed of a transparent filler for filling unevenness of a surface of the half mirror layer to form a flat surface; and

a third optical member that has a transparent thin plate shape and protects an outside surface of the second optical member,

a refractive index of the first optical member, a refractive index of the second optical member, and a refractive index of the third optical member are substantially equal.

2. The display light projection optical device according to claim 1, wherein

light anti-reflection layers is formed on a surface of the first optical member exposed to the outside and a surface of the third optical member exposed to the outside.

3. The display light projection optical device according to claim 1, wherein

the half mirror layer performs as a band stop filter that reflects only a specific wavelength component.

4. The display light projection optical device according to claim 1, wherein

the display light projection optical device is disposed as an intermediate layer of laminated glass of which a vehicle windshield is formed.

6. The display light projection optical device according to claim 1, wherein

the entire shape of the first optical member and the shape of the Fresnel-shaped portion have a curved surface shape conforming to a shape of the vehicle windshield, and

a curvature of a surface of the Fresnel-shaped portion is decided according to a spherical surface expressed with a constant radius or an aspheric surface expressed in a polynomial.

7. The display light projection optical device according to claim 1, wherein

a pitch P at which the plurality of grooves is formed in the Fresnel-shaped portion is an approximate value of the following formula:

P=(tanθ

·

D)/Pixel,

where θ

is a display view angle, D is a distance between an assumed eye point and the Fresnel-shaped portion, and Pixel is a number of vertical or horizontal pixels on a display screen of the display unit.

8. The display light projection optical device according to claim 1, wherein

the half mirror layer is formed on an entire surface, excluding an erect wall region extending in a direction parallel to the thickness direction in boundaries of the plurality of grooves of the Fresnel-shaped portion.

5. The display light projection optical device according to Claim wherein

a disposition state of the Fresnel-shaped portion or an incident target position of the display light is decided so that an optical axis of light incident on the half mirror layer from the display unit is shifted from a center of the concentric form of the Fresnel-shaped portion.