JP3273954B2 - Vehicle head-up display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, about the head-up display device for a vehicle.

[0002]

BACKGROUND OF THE INVENTION driver of an automobile or the like, as a method for information display, so that a head-up display (HUD) is used recently. This information without optical information projected from the information projection unit such as a liquid crystal display device, reflects the half mirror is a combiner incorporated in windshields of automobiles, moving the most perspective driver from the operation state Can be read.

Recently, due to the simplicity of an optical element and the abundance of added functions,
Holograms are gaining attention. Such holographic combiner is not reflection function (diffraction function) only, it is possible to combine the lens function or the like, or diffractive optical information in the sight of the driver, or, without a separate optical lens It is possible to display a far image.

Also, such a holographic HUD
Has a feature that a high-luminance display image can be obtained without deteriorating the foreground luminance.

A hologram having a thickness of several microns to several tens of microns used as a combiner in such a holographic HUD has a curved or planar multilayer grating surface formed in its thin film, and the Bragg reflection by this grating surface is reduced. A display image is formed using the image.

[0006]

[Problems that the Invention is to Solve holographic combiner having such a hologram is generally because they are needed use by sealing the windshield for a vehicle having a curvature, there is a problem that the image is distorted . In particular, for reasons of the recent designs are adapted to relatively sharply bent windshield is required, this problem is serious.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a hologram mounted on a windshield having a curvature, and a display for projecting a display image as a light beam onto the hologram. In a vehicle head-up display device comprising an image projection means,

[0008] The display image projecting means has a display device of a dot matrix type, the display image is to cancel image distortion caused by the hologram is attached to the windshield with a curvature, the vertical direction of the display Along the horizontal
A head-up display device for a vehicle, characterized in that the dots are lit on the display element at positions where the magnification of the direction is changed, so that they are corrected in advance before being projected on the hologram. is there.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a conceptual diagram showing an example of a configuration when a vehicle HUD of the present invention is used in an automobile, wherein 1 is a driver's observation position, 2 is a holographic combiner, and 3 includes a display image. Light beam, 4 is a display image, 5 is a display image projection means,
Reference numeral 6 denotes an aspheric lens for correcting a display image provided as needed, reference numeral 7 denotes a windshield, and reference numeral 8 denotes a vehicle body.

[0010] via the light guide means such as a reflecting means by the optical line 3 Suitable display image correcting means such as a non-spherical lens 6, and must include a display image emitted from the display image projection unit 5, windshield of a motor vehicle The holographic combiner 2 provided on the glass 7 is irradiated, reflected (diffracted) and displayed as a display image 4 at the observation position 1 by the driver. The display image projecting means 5 may be a light receiving type display element such as a liquid crystal display element in combination with an appropriate light source, or a light emitting type display element such as a semiconductor optical device such as an LED arranged in a pattern. It may be.

In the present invention, the display image so as to cancel image distortion caused by the hologram is attached to the windshield with a curvature, that one scratch that is pre-corrected prior to being projected onto the hologram Features.

[0012] As a means for correcting the display image as described above, it may be used an optical system such as a non-spherical lens as necessary as in FIG. 2, for correcting the display of the display image projection unit 5 itself . In order to correct the display of the display image projection unit 5 itself is performed by a table示素Ko assumed dot Matrigel Tsu box type, in advance calculates the position of the dots to be lighted after the correction. In any case, at each position of the display, the display is enlarged (or reduced) in the horizontal or vertical direction by an appropriate amount.

[0013] An example of a method of knowing the amount of correction, such as holograms to cancel image distortion caused by being mounted on the windshield having a curvature below.

[0014] In general, any coordinate of the image (x, y), the unit length in the original display which has not been distortion correction each length l _x, shall be distorted l _y, any point on the display (x, y) magnification and c / l _x during distortion correction in the x and y directions in, by (the c the arbitrary constant) c / l _y set, it is possible to correct the distortion.

In practice, windshields, especially for automobiles, usually have a curvature both horizontally and vertically, but generally the curvature in the horizontal direction is greater than the curvature in the vertical direction. Much smaller (ie sharply bent).
Also, at the position where the holographic combiner is usually provided, the horizontal curvature does not change much depending on the horizontal position if the vertical position is the same. The horizontal curvature changes depending on the position. Furthermore, since the curvature in the vertical direction is originally not so large, it does not depend on the vertical position and the horizontal position and does not change much.

[0016] Such a <br/> General nature of the shape of the windshield glass for automobiles, appearance of the distortion is possible simple and effective approximation. That is, a square image on the display image projecting means 5 which has not been subjected to distortion correction is generally distorted into a substantially inverted trapezoidal shape as shown in FIG. 3 by being diffracted by the combiner of the vehicle HUD.

In such a case, the magnification in the horizontal direction changes along the vertical direction rather than the magnification after diffracting the holographic combiner in the horizontal and vertical directions of the display. That is, the fact that the left and right sides of the square in the original display are tilted after diffracting the holographic combiner gives the observer the impression that the image is extremely distorted, and the HUD
Is a serious problem in terms of appearance.

[0018] In this sense, as the display correcting means, along a vertical direction appear and the used ones of varying horizontal magnification. Upon advance corrects the display itself, you a correction to change the horizontal magnification especially along the vertical direction of the display. Since the display image after diffracting the holographic combiner is originally different in magnification from the original display image in the vertical direction and the horizontal direction of the display, in order to correct this, in the display image projection means, It is desirable to make the display itself different between the vertical curvature and the horizontal curvature.

Normally, if a square image in the original display is diffracted by a holographic combiner, the upper side tends to be a so-called inverted trapezoid longer than the lower side, and therefore goes upward along the vertical direction of the display. Therefore, it is preferable to make the distortion such that the magnification is reduced, and particularly to perform the distortion such that the magnification is linearly reduced. In addition, as the design of the windshield for vehicles is diversified, a windshield having an S-shaped vertical cross section is required, so that it may be appropriately adjusted according to the shape.

A description will now be given of another example of obtaining a correction amount for a trapezoid whose original display is a square and which becomes a trapezoid after diffracting the holographic combiner. For example, FIG. 3 shows a display image when a square display pattern is diffracted by a holographic combiner without distortion correction .
Cormorant of each side length W1, W2, H1, and it was trapezoidal H 2. Here, 9 is a hologram, and 10 is a display image. From this, an aspect ratio D1 and an upper / lower side length ratio D2, which are deformation amounts represented by the following equations, are obtained.

D1 = (H1 + H2) / (W1 + W2) D2 = 0.5 × (W1-W2) / (W1 + W2)

When the original display pattern which becomes a square after diffracting the holographic combiner is expressed as a trapezoid having the respective side lengths w1, w2, h1, and h2 as shown in FIG. It is as follows (C
Is any constant).

W1 = C · W1 w2 = C · W2 (1-D2) h1 = C · H2 / D1 h2 = C · H1 / D1

[0024] Incidentally, FIG. 1, on the liquid crystal display device 11 of the dot Matrigel Tsu box type, such display patterns 12
FIG. By distorting the entire display image similarly to such a trapezoid, a display after holographic combiner diffraction close to the original display can be obtained.

[0025]

According to the present invention, a good-looking holographic HUD that is close to the original display and has little image distortion can be obtained.

[Brief description of the drawings]

[1] on the liquid crystal display element of dot Matrigel Tsu box type, plan view of a material obtained by displaying the Viewing pattern distortion correction by the present invention

FIG. 2 is a conceptual diagram showing an example of the holographic HUD of the present invention.

FIG. 3 is a plan view when a square display pattern is diffracted by a holographic combiner without distortion correction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Observation position 2 Holographic combiner 3 Light beam containing display image 4 Display image 5 Display image projection means

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI H04N 5/74 H04N 5/74 D (56) References JP-A-2-299934 (JP, A) JP-A-64-38718 ( JP, A) JP-A-1-282048 (JP, A) JP-A-61-57434 (JP, A) JP-A-62-5288 (JP, A) JP-A-2-88834 (JP, U) Hei3-500340 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G09F 9/00 B60K 35/00

Claims (1)

(57) [Claims] 1. A head-up display device for a vehicle, comprising: a hologram mounted on a windshield having a curvature; and a display image projecting means for projecting a display image as a light beam onto the hologram, wherein the display image projecting means is a dot matrix. The display image has a horizontal magnification along the vertical direction of the display, which cancels image distortion caused by mounting the hologram on a windshield having a curvature.
A head-up display device for a vehicle, wherein a dot is lit on the display element at a position where the hologram is to be converted, so that the dot is corrected before being projected on the hologram.