Vehicular head up display

• US 6,608,608 B2
• Filed: 01/17/2001
• Issued: 08/19/2003
• Est. Priority Date: 01/17/2000
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kanamori, Naohito
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US09/760,736
• Publication Number:
  US 20010008394A1
• Time in Patent Office: 944 Days
• Field of Search: 345/7, 345/8, 345/87, 315/64, 307/10.1, 349/11, 349/57, 359/636
• US Class Current: 345/8
• CPC Class Codes: B60K 2360/33 Illumination features
• CPC Class Codes: B60K 2360/334 Projection means
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133626 providing two modes of illumination, e.g. day-night
• CPC Class Codes: G02F 2201/58 Arrangements comprising a monitoring photodetector
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A light source of a liquid crystal panel employed in a head up display for a vehicle has an embedded filament for emitting a light with high luminance and another embedded filament for emitting a light with low luminance. The embedded filament for emitting a light with low luminance is used for a first luminance range. On the other hand, the embedded filament for emitting a light with high luminance is used for a second luminance range. In addition, both the elements may be used at the same time for emitting a light with maximum luminance of the first range and the second range.

Claims

1. A head up display for a vehicle, comprising:

a light source provided on a back-surface side of an instrument panel located below a front wind shield in the vehicle compartment of the vehicle, said light source emitting light along a path;

a liquid crystal display unit provided on the back-surface side of the instrument panel along said path, said liquid crystal display unit filtering light from the light source to display light representing information;

an optical element that directs light filtered by the liquid crystal display unit through an opening in the instrument panel to the front wind shield, light projected onto said front wind shield by said optical element forming an image on the wind shield; and

the front wind shield reflecting light from the optical element to generate a virtual image for a vehicle occupant;

the head up display further comprising;

a brightness-sensing means that senses brightness outside the vehicle;

a setting means that sets a light-control illumination of the light source to a value corresponding to the brightness outside the vehicle; and

control means that controls luminance of light emitted by the light source according to the brightness outside the vehicle and the light-control illumination wherein;

the light source has a plurality of embedded filaments, each of the embedded filaments having a luminance level different from a remainder of the plurality of embedded filaments;

the control means controls the luminance of light emitted by the light source by driving a filament with a low luminance selected from the plurality of filaments when light emitted from said light source is set low;

the control means controlling luminance of light emitted by the light source by driving at least a filament with a high luminance selected from the plurality of filaments when light emitted from said light source is set large;

an applied voltage to said filament with low luminescence varies hyperbolically to a luminance of said filament with low luminance, an applied voltage to said filament with said high level of luminescence varies hyperbolically with said filament with said high level of luminance;

a voltage change being larger per a luminescence change for said filament with a low level of luminance relative to a voltage change per a luminescence change for said filament with a high level of luminance; and

the control means selecting one of two filaments based on said hyperbolic relationships, said control means determining an applied for the selected filament and driving the selected filament by applying the determined applied voltage.

2. A head up display for a vehicle according to claim 1, wherein said filament with low luminance has a tungsten wire having a size and width smaller than said filament with high luminance.