Vehicle head-up display device

Patent metadata

Field	Value
Publication number	US-2016178901-A1
Application number	US-201414909908-A
Country	US
Kind code	A1
Filing date	Jul 30, 2014
Priority date	Aug 6, 2013
Publication date	Jun 23, 2016
Grant date	—

Abstract

In a vehicle head-up display device that reflects a display light transmitted through a dust-proof cover on a windshield or a combiner, and viewably displays display information as a virtual image from a driver's seat of a vehicle, the dust-proof cover has a light transmissive property produced by being rolled, when a line between a first point a first end side of the display in a longitudinal direction of the display and a second point being at the same height as the first point in a second end side opposite to the first end side is a longitudinal axis, and a luminance of a virtual image is adjusted by adjusting an angle between a rolling direction of a resin sheet used for the dust-proof cover and a virtual image longitudinal axis, which corresponds to the longitudinal axis, of a virtual image of the display reflected by the reflector. As a result, a polarization state of the display light is changed to enable the luminance of the virtual image to be adjusted without any increase in the number of parts and a body size.

First claim

What is claimed is:

1 . A vehicle head-up display device, comprising:
a casing that is disposed close to a driver's seat of a vehicle and has an opening, the vehicle having a windshield or a combiner disposed separately from the windshield; a light emitting element that is housed in the casing; a display that is housed in the casing and emits a display light indicating display information upon receiving a light emitted by the light emitting element; a reflector that is housed in the casing and reflects the display light; and a dust-proof cover that is made of a resin sheet and is disposed in the opening, wherein the display light transmitted through the dust-proof cover is reflected on the windshield or the combiner, whereby the display information is displayed as a virtual image to be visible from the driver's seat of the vehicle, the dust-proof cover, which is formed by rolling the resin sheet in a rolling direction, has a light transmission property, a line passing between a first point in a first end side of the display in a longitudinal direction of the display and a second point in a second end side of the display opposite to the first end side is defined as a longitudinal axis, the second point being at a same height as the first point, an angle between the rolling direction of the resin sheet and a virtual image longitudinal axis, which corresponds to the longitudinal axis, of the virtual image of the display reflected by the reflector is defined as an angle α, and a luminance of the virtual image is adjusted by adjusting the angle α.

2 . The vehicle head-up display device according to claim 1 , wherein
a luminance of the light emitting element is I 0 , a transmittance of the display is T TFT , a reflectance of the reflector is R, an angle between the longitudinal axis and a polarization direction of the display light is θ LCD , an angle between a virtual plane and a plane is defined as an angle Δθ, the virtual plane being defined by an incident light and a reflected light of the display light when reflected on the windshield or the combiner, and the plane being perpendicular to the virtual image longitudinal axis of the virtual image of the display reflected by the reflector, a reflectance of an s-polarized light on the windshield or the combiner is Rs, a reflectance of a p-polarized light on the windshield or the combiner is Rp, values determined by a characteristic of the dust-proof cover are A 1 and A 2 , a luminance I of the display information, when visually recognized as the virtual image from the driver's seat, is represented by the following Expression 1:
I =( I 0 ·T TFT ·R )×[ Rs·{A 1 cos 2 (θ LCD +Δθ−2α)+ A 2 cos 2 (θ LCD +Δθ)}+ Rp·{A 1 sin 2 (θ LCD +Δθ−2α)+ A 2 sin 2 (θ LCD +Δθ)}]  [Expression 1]

and
the angle α is selected so that the luminance I falls within a range of from 65% to 90% of a maximum value of the luminance I.

3 . The vehicle head-up display device according to claim 1 , wherein
a luminance of the light emitting element is I 0 , a transmittance of the display is T TFT , a reflectance of the reflector is R, an angle between the longitudinal axis and a polarization direction of the display light is θ LCD , an angle between a virtual plane and a plane is defined as an angle Δθ, the virtual plane being defined by an incident light and a reflected light when the display light is reflected on the windshield or the combiner, and the plane being perpendicular to the virtual image longitudinal axis of the virtual image of the display reflected by the reflector, a reflectance of an s-polarized light on the windshield or the combiner is Rs, a reflectance of a p-polarized light on the windshield or the combiner is Rp, values determined by a characteristic of the dust-proof cover are A 1 and A 2 , a luminance I of the display information, when visually recognized as the virtual image from the driver's seat, is represented by the following Expression 1:
I =( I 0 ·T TFT ·R )×[ Rs·{A 1 cos 2 (θ LCD +Δθ−2α)+ A 2 cos 2 (θ LCD +Δθ)}+ Rp·{A 1 sin 2 (θ LCD +Δθ−2α)+ A 2 sin 2 (θ LCD +Δθ)}]  [Expression 1]

and
the angle α is selected so that the luminance I becomes a value other than a maximum value and a minimum value of the luminance I.

4 . The vehicle head-up display device according to claim 1 , wherein
a luminance of the light emitting element is I 0 , a transmittance of the display is T TFT , a reflectance of the reflector is R, an angle between the longitudinal axis and a polarization direction of the display light is θ LCD , an angle defined between a virtual plane and a plane is defined as an angle Δθ, the virtual plane being defined by an incident light and a reflected light when the display light is reflected on the windshield or the combiner, and the plane being perpendicular to the virtual image longitudinal axis of the virtual image of the display reflected by the reflector, a reflectance of an s-polarized light on the windshield or the combiner is Rs, a reflectance of a p-polarized light on the windshield or the combiner is Rp, values determined by a characteristic of the dust-proof cover are A 1 and A 2 , a luminance I of the display information, when visually recognized as the virtual image from the driver's seat, is represented by the following Expression 1,
I =( I 0 ·T TFT ·R )×[ Rs·{A 1 cos 2 (θ LCD +Δθ−2α)+ A 2 cos 2 (θ LCD +Δθ)}+ Rp·{A 1 sin 2 (θ LCD +Δθ−2α)+ A 2 sin 2 (θ LCD +Δθ)}]  [Expression 1]

and
the angle α is selected so that the luminance I has a maximum value of the luminance I.

5 . The vehicle head-up display device according to claim 2 , wherein
the values A 1 and A 2 are set to satisfy 0.3<A 1 <0.5 and 0.39<A 2 <0.59, respectively.

6 . The vehicle head-up display device according to claim 1 , wherein
the dust-proof cover is made of polycarbonate.

7 . The vehicle head-up display device according to claim 1 , wherein
the dust-proof cover is made of acrylic.

8 . The vehicle head-up display device according to claim 1 , wherein
the dust-proof cover is made of the resin sheet formed through a rolling process.

Assignees

• Denso Corp

Inventors

• Ishikawa Toshiki

Classifications

• B60K35/235

  with means for detecting the driver's gaze direction or eye points · CPC title

• G02B2027/0154

  with movable elements · CPC title

• G02B27/0006

  with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B) · CPC title

• G02B27/0149

  characterised by mechanical features (G02B27/0176 takes precedence) · CPC title

• G02B2027/0118

  comprising devices for improving the contrast of the display / brillance control visibility · CPC title