US 12,135,422 B2
Virtual image display device
Yasunori Ninomiya, Kariya (JP)
Assigned to DENSO CORPORATION, Kariya (JP)
Filed by DENSO CORPORATION, Kariya (JP)
Filed on Jul. 20, 2021, as Appl. No. 17/380,644.
Application 17/380,644 is a continuation of application No. PCT/JP2020/000808, filed on Jan. 14, 2020.
Claims priority of application No. 2019-017227 (JP), filed on Feb. 1, 2019.
Prior Publication US 2021/0349313 A1, Nov. 11, 2021
Int. Cl. G02B 27/01 (2006.01); B60K 35/00 (2024.01); B60K 35/23 (2024.01)
CPC G02B 27/0101 (2013.01) [B60K 35/00 (2013.01); B60K 35/23 (2024.01); B60K 2360/23 (2024.01)] 18 Claims
OG exemplary drawing
 
1. A virtual image display device for displaying a virtual image, comprising:
a display that emits display light that is to be imaged as the virtual image;
a reflective mirror that has a reflective surface to reflect the display light emitted from the display; and
a housing that houses the display and the reflective mirror and has an opening through which the display light reflected by the reflective mirror exits the housing, wherein
the housing includes a wall structure on a portion of a surface of the housing such that an external light that enters the housing through the opening from an outside of the housing and is reflected by the reflective surface reaches the wall structure,
the wall structure includes a plurality of first walls that face in a first common direction and a plurality of second walls that face in a second common direction different from the first common direction,
the plurality of first walls and the plurality of second walls are alternately arranged and are connected to each other one by one along the surface of the housing,
a space where the virtual image is visible is defined as a visible area,
a straight line extending from one end of the reflective surface to a first wall is defined as an end reference first straight line,
an angle formed by the first wall with respect to the end reference first straight line is defined as an end reference first wall angle that is formed on a side of the first wall opposite to the one end of the reflective surface, wherein the end reference first wall angle is positive when formed on an exposed side of the surface with respect to the end reference first straight line and is negative when formed on a side opposite to the exposed side,
an angle formed by the first wall with respect to the end reference first straight line is defined as a visible area first critical angle that is formed on a side of the first wall opposite to the one end of the reflective surface, wherein the visible area first critical angle is positive when formed on the exposed side of the surface with respect to the end reference first straight line and is negative when formed on the side opposite to the exposed side, and the visible area first critical angle is virtually set such that a light travelling along the end reference first straight line from the one end of the reflective surface and incident on the first wall reaches one end of the visible area after reflected by the first wall,
a straight line extending from the other end of the reflective surface to a second wall is defined as an end reference second straight line,
an angle formed by the second wall with respect to the end reference second straight line is defined as an end reference second wall angle that is formed on a side of the second wall opposite to the other end of the reflective surface, wherein the end reference second wall angle is positive when formed on the exposed side of the surface with respect to the end reference second straight line and is negative when formed on the side opposite to the exposed side,
an angle formed by the second wall with respect to the end reference second straight line is defined as a visible area second critical angle that is formed on a side of the second wall opposite to the other end of the reflective surface, wherein the visible area second critical angle is positive when formed on the exposed side of the surface with respect to the end reference second straight line and is negative when formed on the side opposite to the exposed side, and the visible area second critical angle is virtually set such that a light travelling along the end reference second straight line from the other end of the reflective surface and incident on the second wall reaches the other end of the visible area after reflected by the second wall, and
each first wall and each second wall are formed such that the end reference first wall surface angle is larger than the end reference second wall surface angle, the end reference first wall angle is larger than the visible area first critical angle, and the end reference second wall angle is smaller than the visible area second critical angle.