US 12,013,532 B2
Head-up display
Takato Hada, Osaka (JP); and Tomoaki Miyamoto, Osaka (JP)
Assigned to PANASONIC AUTOMOTIVE SYSTEMS CO., LTD., Kanagawa (JP)
Filed by PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Filed on May 25, 2023, as Appl. No. 18/201,962.
Application 18/201,962 is a continuation of application No. 17/849,156, filed on Jun. 24, 2022, granted, now 11,703,686.
Application 17/849,156 is a continuation of application No. 17/171,484, filed on Feb. 9, 2021, granted, now 11,402,632, issued on Aug. 2, 2022.
Claims priority of application No. 2020-023267 (JP), filed on Feb. 14, 2020; and application No. 2020-185448 (JP), filed on Nov. 5, 2020.
Prior Publication US 2023/0296892 A1, Sep. 21, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 27/01 (2006.01); B60K 35/00 (2024.01); B60K 35/23 (2024.01); B60K 35/60 (2024.01)
CPC G02B 27/0101 (2013.01) [B60K 35/00 (2013.01); B60K 35/23 (2024.01); B60K 35/60 (2024.01); B60K 2360/23 (2024.01); B60K 2360/31 (2024.01); B60K 2360/334 (2024.01); B60K 2360/785 (2024.01); G02B 2027/0118 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A head-up display, comprising:
a display that displays an image; and
a projection optical system that forms a virtual image,
wherein the projection optical system includes:
a first mirror that is disposed above the display and reflects display light of the image; and
a second mirror that reflects the display light from the first mirror toward a display medium onto which the virtual image is projected,
wherein the second mirror includes a free form surface, and
the free form surface is defined by a first expression and a second expression, where
the first expression is

OG Complex Work Unit Math
the second expression is

OG Complex Work Unit Math
z denotes a sag height at a position (x, y) relative to an axis that defines a plane,
r denotes a numerical value calculated by a third expression that is satisfied,
the third expression is r=√x2+y2,
c denotes a curvature at an origin of the axis that defines the plane,
k denotes a conic constant,
m and n denote integers that satisfy the second expression,
Cj denotes a coefficient of xmyn in a polynomial, and
an absolute value of Cj is less than or equal to 1.9694.