On-vehicle display apparatus

• US 20090073327A1
• Filed: 09/18/2007
• Published: 03/19/2009
• Est. Priority Date: 09/18/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shibata, Hirokazu, Watanabe, Yoshinori
• Granted Patent: US 8,368,823 B2
• Time in Patent Office: Days
• US Class Current: 348/837
• CPC Class Codes: G01C 21/36 Input/output arrangements for on-board computers
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2380/10 Automotive applications
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 5/024 using colour registers, e.g. to control background, foreground, surface filling G09G5/06 takes precedence

Abstract

A display apparatus for a vehicle includes a liquid crystal panel, a backlight unit, and a control circuit. The liquid crystal panel has a screen constructed with pixels. A first portion of the pixels displays a speed image indicating a vehicle speed. A second portion of the pixels displays a warning image indicating a vehicle abnormal condition. The control circuit adjusts brightness of the screen by controlling intensity of colors in the speed and warning images in such a manner that brightness of the warning image is greater than brightness of the speed image. The luminance of the light supplied to the screen by the backlight unit is kept constant.

Claims

1. A display apparatus for a vehicle comprising:

a liquid crystal panel that has a display screen constructed with a plurality of pixels, a first portion of the plurality of pixels being configured to display a speed image indicating a speed of the vehicle, a second portion of the plurality of pixels being configured to display a warning image indicating an abnormal condition of the vehicle, a third portion of the plurality of pixels being configured to display a background image serving as a background of both the speed image and the alarm image;

a drive circuit coupled to the liquid crystal panel to drive the liquid crystal panel;

a light source configured to backlight the liquid crystal panel to supply light to the display screen of the liquid crystal panel;

a setting device configured to set brightness of the display screen of the liquid crystal panel to a predetermined level, and

a control circuit coupled between the setting device and the drive circuit,

wherein the control circuit adjusts the brightness of the display screen of the liquid crystal panel based on an input from the setting device by controlling the drive circuit in such a manner that a first intensity value of the first portion of the plurality of pixels varies in accordance with the input from the setting device and a second intensity value of the second portion of the plurality of pixels is constant regardless of the input from the setting device,

wherein the first and second intensity values are selected so that brightness of the warning image is greater than brightness of the speed image, and

wherein luminance of the light supplied to the display screen by the light source is constant regardless of the input from the setting device.

2. The display apparatus according to claim 1,

wherein an entire region of the display screen is configured to display a vehicle information image indicating a condition of the vehicle, and

wherein the vehicle information image includes the speed image and the warning image.

3. The display apparatus according to claim 1,

wherein the warning image indicates at least one of a coolant temperature and a fuel level of the vehicle.

4. The display apparatus according to claim 1,

wherein the control circuit includes a memory device that stores the first intensity value of the speed image, the second intensity value of the warning image, and a third intensity value of the background image,

wherein the control circuit reads the first, second, and third intensity values from the memory device, and

wherein the speed image, the warning image, and the background image are displayed on the display screen based on the first, second, and third intensity values, respectively.

5. The display apparatus according to claim 1,

wherein the control circuit includes a calculation circuit that calculates the first intensity value of the speed image, the second intensity value of the warning image, and a third intensity value of the background image in accordance with the brightness of the display screen.

6. The display apparatus according to claim 5,

wherein the calculation circuit calculates the first, second, and third intensity values by multiplying reference intensity values by predetermined coefficient factors, respectively.

7. The display apparatus according to claim 1,

wherein the setting device includes an input device that allows a user to set the brightness of the display screen.

8. A display apparatus for a vehicle comprising:

a liquid crystal panel that has a display screen constructed with a plurality of pixels, a first portion of the plurality of pixels being configured to display a speed image indicating a speed of the vehicle, a second portion of the plurality of pixels being configured to display a warning image indicating a warning condition of the vehicle, a third portion of the plurality of pixels being configured to display a background image serving as a background of both the speed image and the alarm image;

a driver circuit coupled to the liquid crystal panel to drive the liquid crystal panel;

a light source configured to backlight the liquid crystal panel to supply light to the display screen of the liquid crystal panel;

a setting device configured to set brightness of the display screen of the liquid crystal panel to a predetermined level; and

a control circuit configured to operate in conjunction with the driver circuit and the setting device,

wherein when the brightness of the display screen is set to a lower level by the setting device, the control circuit operates to set a first intensity value of the first portion of the plurality of pixels lower than a second intensity value of the second portion of the plurality of pixels so that brightness of the warning image is greater than brightness of the speed image, the second intensity value being constant regardless of the brightness of the display screen so that the brightness of the warning image being constant regardless of the brightness of the display screen, and

wherein luminance of the light supplied to the display screen by the light source is constant regardless of the brightness of the display screen.

9. The display apparatus according to claim 8,

wherein an entire region of the display screen is configured to display a vehicle information image indicating a condition of the vehicle, and

wherein the vehicle information image includes the speed image and the warning image.

10. The display apparatus according to claim 8,

wherein the warning image indicates at least one of a coolant temperature and a fuel level of the vehicle.

11. The display apparatus according to claim 8,

wherein the setting device includes an input device that allows a user to set the brightness of the display screen.

12. The display apparatus according to claim 9,

wherein the vehicle information image further includes a navigation image sent from a navigation system of the vehicle, and

wherein when the brightness of the display screen is set to the lower level by the setting device, the control circuit operates so that the brightness of the warning image is greater than brightness of the navigation image.

13. The display apparatus according to claim 12,

wherein the navigation image includes a navigation warning image indicating a warning condition of the navigation, and

wherein when the brightness of the display screen is set to the lower level by the setting device, the control circuit operates so that the brightness of the warning image is greater than brightness of the navigation image except for the navigation warning image, and the control circuit operates so that brightness of the navigation warning image is kept constant regardless of the brightness of the display screen.

14. The display apparatus according to claim 13,

wherein the navigation warning image indicates at least one of an abnormal condition of the navigation system and a route to a predetermined destination.