JP2504097Y2 - Projector type vehicle headlight - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a projector-type vehicle headlight,
In particular, the present invention relates to a projector-type vehicle headlamp that is improved so that spectral color does not appear near the cut line.

[Conventional technology]

The vehicle headlamp must have a light distribution pattern that brightly illuminates the front road surface in the own lane and does not dazzle oncoming vehicles.

A projector-type automotive headlamp has been proposed as a headlamp that has a light distribution characteristic that meets the above requirements, has a simple lens configuration, and can be downsized in its overall shape. As a basic technique relating to this projector type headlight, for example, Japanese Patent Application Laid-Open No. 58-209801 is known.

FIG. 4 is a plan view schematically illustrating an example of this type of projector-type headlight, FIG. 5 is a side view thereof, and FIG. 6 is a front view thereof.

Reference numeral 1 is a concave mirror, and F ₁ is its first focal point. Focus on above F ₁
The light source bulb 2 is provided so that the filament is located nearby.

An optical axis Z is shared with the concave mirror 1 and a convex lens 3
Is provided.

Reference numeral i-j in FIG. 4 denotes the meridional image plane of the convex lens 3, and the light emitted from the light source bulb 2 and reflected by the concave mirror 1 is incident on this meridional image plane.

The incident light is dimmed by the convex lens 3 and projected forward (rightward in FIGS. 4 and 5).

By providing a screen near the meridional image plane,
The light distribution pattern is shown by an isoilluminance curve as shown in FIG. H-H is a horizontal line on the screen, and V-V is a vertical line.

As shown in FIGS. 4 to 6, a shade 4 having an edge along the meridional image plane is provided. Specifically, as shown by 4a in FIG. 6, a horizontal section i-j of the meridional image plane is shown.
A cut line 4a is formed so as to recede downward from.
FIG. 7 shows the degree of overlap between the above-mentioned light distribution pattern and the shade 4. As shown in FIG. 7,
The upper half of the light flux passes through. Most of the lower half is blocked,
Light can pass through the portion corresponding to the cut line 4a.

Since the luminous fluxes partially covered as described above are condensed on the meridional image plane i-j and intersect each other, the luminous flux projected in front of the headlight has a pattern of an inverted shape of FIG. To form. FIG. 8 is an explanatory view showing a schematic shape of a projection pattern by an isolux curve on a screen provided in front of the headlight.

This conventional example is configured for left-hand traffic, and in the case of right-hand traffic, FIGS.

FIG. 9 is a perspective view schematically illustrating a conventional example of a projector type headlight, where 1 is a concave mirror, 2 is a light source bulb, and 3 is a light source bulb.
Is a convex lens. In this example, the shade 4 having the cut line 4a having the cut angle θ is provided. The shaded parallel lines on the shade 4 are a schematic representation of an opaque material, and do not mean a cross section.

When the screen 5 is illuminated by the projector-type headlight having the above-described configuration, the projection pattern shown in the figure is obtained. However, the portion with parallel diagonal lines on the screen 5 indicates that it is not illuminated, and does not mean a cross section.

The area L drawn in white on the screen 5 is an illuminated area, and the shape of the upper side thereof is that in which the cut line 4a of the shade 4 is enlarged and inverted.
θ is the cut angle of the cut line 4a.

Here, 4a is a cut line of the shade, and 5a is a cut line of the light distribution pattern.

[Problems to be solved by the device]

If the convex lens 3 is composed of a single lens, a spectral color appears at the upper edge of the illumination area of the light distribution pattern, that is, in the vicinity of the cut line 5a, which does not comply with the regulations.

In practice, red and blue are visually conspicuous, it is difficult to drive, and there is a risk of danger to oncoming vehicles.

Known techniques for erasing or reducing the above-mentioned spectral colors include (i) using a filter, as disclosed in JP-A-58-140901.
And U.S. Pat.Nos. 4222027, 3999056, 3737653,
And JP-A-4101957, and (ii) the one using a double lens is disclosed in JP-A-62-50257.
7, JP-A 61-49302 and JP-A 60-62001.

(Iii) In addition, there are projector type headlamps manufactured by Bosch that use stepped lenses and projector headlamps manufactured by Heller that are equipped with a diffusion lens (as an outer lens), and are permitted in Japan. Has been publicly known.

However, among these known projector-type headlights, those using a stepped lens are not easy to manufacture and the cost is high. In addition, other known projector-type headlamps have a large number of constituent parts, resulting in high cost.

In addition to the above (i) to (iii), JP-A-63-228503 is known as a technique for reducing spectral color with a simple structure.
In this known technique, a reflective surface is provided on the upper end surface of the shade.

By increasing the thickness of the shade and using the upper end surface as a reflective surface in this way, it is possible to compensate for the insufficient amount of light in the light distribution pattern by the reflected light from this reflective surface. The effect of reducing the spectral phenomenon by providing the reflecting surface is not sufficient.

This is because even if white light is reflected by this reflecting surface, it is dispersed when passing through the convex lens 3.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projector-type automotive headlamp that has a simple structure and prevents the development of spectral colors in the vicinity of the cut line.

[Means for solving the problem]

In order to achieve the above object, the projector type headlight of the present invention absorbs light having a wavelength close to red light and light having a wavelength close to blue light on the upper end surface of the shade,
An optical member that reflects light of other wavelengths is provided. In the present invention, the optical member means a constituent part utilizing its optical characteristics, and is, for example, a coating film or a multilayer film, which selectively absorbs light of a specific wavelength. .

[Action]

In the projector type headlamp configured as described above, the light reflected at the upper end of the shade lacks the red component and the blue component.

The light of this special component overlaps with the light not reflected at the upper end of the shade in the vicinity of the cut line of the light distribution pattern.

Of the light that is not reflected at the upper end of the shade, the light that reaches the cut line of the light distribution pattern has a red component and / or a blue component that are excessive due to a spectral phenomenon.

In this way, the light lacking the red and blue components and the light with excess red and / or blue components overlap, resulting in a state similar to that illuminated with white light, and the spectral color is felt. I will not be able to.

〔Example〕

FIG. 2 is a schematic side view showing an embodiment of a projector type vehicle headlight according to the present invention, and is a view corresponding to FIG. 5 in a conventional example. The difference from FIG. 5 is that a selective absorption layer 7 as an optical member is provided on the upper end surface of the shade 4. An enlarged view of this part is shown in FIG.

The selective absorption layer 7 of this example was composed of a multilayer film. The above multilayer film is formed by laminating a plurality of transparent films having different refractive indexes,
Silicon oxide (SiO ₂ ), titanium oxide (Ti) that selectively transmits, reflects, and absorbs light in a specific wavelength band by utilizing light interference
It is an optical member formed by alternately stacking O ₂ ).

The selective absorption layer 7 of this example is configured to absorb red light of 600 nm or more and blue light of 450 nm or less and reflect light of other wavelength bands (450 to 600 nm).

Therefore, when the white light shown in FIG. ₁ is incident on the selective absorption layer 7 as indicated by arrows a ₁ , a ₂ , and a ₃ , the light from which the red component and the blue component are removed is indicated by the arrows b ₁ , b ₂ , and Reflect as b ₃ . Shade 4
Is preferably formed in black so as to prevent reflection on its surface.

White light (arrow a ₄ ) that has not entered the selective absorption layer 7 is
It passes through as white light as indicated by arrow a ₄ ′.

FIG. 3 is an explanatory view of the operation and effect of this embodiment, and is a schematic drawing of the outline of the light distribution pattern on the screen illuminated by the headlight.

The light flux not blocked by the shade 4 and not reflected by the selective absorption layer 7 has a light distribution pattern as shown in FIG. 3 (A), and a spectral band 8 is generated along the cut line.

A red portion 8r appears on the outer peripheral side of this spectral band, and a blue portion 8b appears on the inner peripheral side. When observed in detail, the so-called seven colors of the rainbow are dispersed, but when viewed from the driver's standpoint, red and blue are noticeable.

The light (arrows b ₁ , b ₂ , b ₃ ) lacking the red and blue components described in FIG. 1 is specularly reflected near the cut line of the shade 4, so that the light is distributed near the cut line of the light distribution pattern. Then, a pattern 9 as shown in FIG. 3 (B) is formed.

Actually, the light distribution pattern of FIG. 3 (A) and the light distribution pattern of FIG. 3 (B) overlap as shown in FIG. 3 (C).

Then, in the vicinity of the cut line of the light distribution pattern, the spectral band 8 in which the red / blue component is excessive and the band 9 of light in which the red / blue component is lacking overlap each other, and visually become substantially white light.

In the present embodiment, as described above, the shade 4
With the simple configuration in which the selective absorption layer 7 is provided on the upper end portion of the above, it is possible to prevent the development of the spectral color in the cut line of the light distribution pattern.

[Effect of device]

According to the projector type automobile headlight of the present invention,
With a simple configuration, it is possible to prevent the spectral color from developing near the cut line.

[Brief description of drawings]

1 to 3 show an embodiment of a projector-type vehicle headlight according to the present invention. FIG. 1 is an enlarged sectional view near the upper end of a shade, and FIG. 2 is a side view schematically drawn. FIGS. 3 (A) to 3 (C) are explanatory views of the action and effect. 4 to 6 show a conventional projector type headlight, FIG. 4 is a plan view, FIG. 5 is a side view, and FIG. 6 is a front view. FIG. 7 and FIG. 8 are tables showing the optical characteristics of the above conventional example. FIG. 9 is an explanatory view of a conventional example. DESCRIPTION OF SYMBOLS 1 ... Concave mirror, 2 ... Light source bulb, 3 ... Convex lens, 4 ... Shade, 7 ... Selective absorption layer as an optical member, 8 ... Spectral band, 9 ...
Light that lacks red and blue components.

Claims (1)

(57) [Scope of utility model registration request] 1. A light source bulb is installed in the vicinity of a first focal point of a concave mirror, and light emitted from the light source bulb is reflected by the concave mirror to form a second focal point in the vicinity of a shade having a cut line, and the reflected light is reflected by a convex lens. In a projector-type automobile headlight that projects forward, the upper end surface of the shade absorbs light having a wavelength near red light, and light having a wavelength near blue light, and emits light having other wavelengths. A projector-type vehicle headlight, comprising an optical member for reflecting the light.