Headup display device and method for indicating virtual image

• US 20110102483A1
• Filed: 11/03/2010
• Published: 05/05/2011
• Est. Priority Date: 11/05/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kanamori, Naohito
• Granted Patent: US 8,593,373 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: B60K 2360/334 Projection means
• CPC Class Codes: B60K 2360/349 Adjustment of brightness
• CPC Class Codes: B60K 2370/1529 Head-up displays
• CPC Class Codes: B60K 2370/334 Projection means
• CPC Class Codes: B60K 2370/349 Adjustment of brightness
• 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 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2380/10 Automotive applications
• CPC Class Codes: G09G 2380/12 Avionics applications
• CPC Class Codes: G09G 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT

Abstract

A headup display device controls a brightness of an image according to a present illumination in an environment of a vehicle and projects the image to a front windshield of the vehicle to indicate the image as a virtual image in an interior of the vehicle. An illumination determination unit determines a present illumination by multiplying an increasing rate by an interior illumination in the interior of the vehicle when being in a light-adapted state, in which the interior of the vehicle is lighter than the exterior of the vehicle. The illumination determination unit determines the present illumination by multiplying a decreasing rate by an exterior illumination in the exterior of the vehicle when being in a dark-adapted state, in which the interior of the vehicle is darker than the exterior of the vehicle. A brightness control unit controls the brightness to correspond to the determined present illumination.

Claims

1. A headup display device configured to control a brightness of an image according to a present illumination in an environment of a vehicle and project the image to a front windshield of the vehicle to indicate the image as a virtual image in an interior of the vehicle, the headup display device comprising:

an illumination determination unit configured to;

determine the present illumination by multiplying an increasing rate by an interior illumination, which is an illumination in the interior of the vehicle, in a light-adapted state, in which an interior of the vehicle is lighter than an exterior of the vehicle; and

determine the present illumination by multiplying a decreasing rate by an exterior illumination, which is an illumination in the exterior of the vehicle, in a dark-adapted state, in which an interior of the vehicle is darker than the exterior of the vehicle; and

a brightness control unit configured to control the brightness at a brightness corresponding to the present illumination determined by the illumination determination unit.

2. The headup display device according to claim 1, wherein

in the light-adapted state, the illumination determination unit is further configured to:

set a rate, which is to be multiplied by the interior illumination for determining the present illumination, to the increasing rate when an illumination difference between the interior illumination and the exterior illumination is greater than or equal to a predetermined light adaptation threshold; and

switch the rate, which is to be multiplied by the interior illumination for determining the present illumination, from the increasing rate to a constant rate when the illumination difference is less than the light adaptation threshold.

3. The headup display device according to claim 1, wherein

in the dark-adapted state, the illumination determination unit is further configured to:

set a rate, which is to be multiplied by the exterior illumination for determining the present illumination, to the decreasing rate when an illumination difference between the interior illumination and the exterior illumination is greater than or equal to a predetermined dark adaptation threshold; and

switch the rate, which is to be multiplied by the exterior illumination for determining the present illumination, from the decreasing rate to a constant rate when the illumination difference is less than the dark adaptation threshold.

4. The headup display device according to claim 2, wherein the illumination determination unit is further configured to determine the illumination difference according to the exterior illumination in a vehicle front region including a focus position of the virtual image.

5. The headup display device according to claim 3, wherein the illumination determination unit is further configured to determine the illumination difference according to the exterior illumination in a vehicle front region including a focus position of the virtual image.

6. The headup display device according to claim 2, wherein the brightness control unit includes a storage unit configured to store a correlation, which is common in a relation between the interior illumination and the exterior illumination, as a correlation between the present illumination determined by the illumination determination unit and the brightness corresponding to the present illumination.

7. The headup display device according to claim 3, wherein the brightness control unit includes a storage unit configured to store a correlation, which is common in a relation between the interior illumination and the exterior illumination, as a correlation between the present illumination determined by the illumination determination unit and the brightness corresponding to the present illumination.

8. A method for indicating a virtual image in an interior of a vehicle according to a present illumination in an environment of the vehicle, the method comprising:

determining the present illumination by multiplying an increasing rate by an interior illumination, which is an illumination in the interior of the vehicle, in a light-adapted state, in which an interior of the vehicle is lighter than an exterior of the vehicle;

determining the present illumination by multiplying a decreasing rate by an exterior illumination, which is an illumination in the exterior of the vehicle, in a dark-adapted state, in which an interior of the vehicle is darker than an exterior of the vehicle;

controlling a brightness of an image corresponding to the determined present illumination; and

projecting the image to a front windshield of the vehicle to indicate the image as the virtual image in the interior of the vehicle.