JPS62186402A - Projector type head lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projector type vehicle headlamp.

[Conventional technology]

Automobile headlights must have a light distribution pattern that brightly illuminates the area in front of the driver's lane and does not provide a porthole to oncoming vehicles.

A projector-type automobile headlamp has been proposed as a headlamp that has light distribution characteristics that meet the above requirements, has a simple lens configuration, and can be made compact in overall size. As the latest technology regarding this projector type headlamp, for example, Japanese Patent Laid-Open No. 58-209801 is known.

FIG. 18 shows the above-mentioned known projector type headlamp. The headlight of this known example is provided with a shell-shaped reflector,
The axial cross section of the inner reflective surface of this reflector each forms a part of an ellipse, and the eccentricity of the ellipse increases from the axial vertical longitudinal section to the axial horizontal longitudinal section. In the illumination, the focal point 105 of the intra-vessel portion 10L 102 of all axial sections is also the corresponding vertex 104 of the intra-vessel portion 101.102 of all axial sections.
are configured to match.

110 is the outer focus of the ellipse 102, 110 is the dimmer, 11
2 is the outer focus of the ellipse 101, and 113 is a lens.

[Problem that the invention seeks to solve]

When the reflector is configured using the above-mentioned known technique, the luminous intensity distribution on the installation surface of the dimmer 111 will be as shown in FIG. 19. Although this light intensity distribution curve changes depending on the length of the ellipse and the ratio of short axis to short, it has a certain tendency and is determined by itself, and there is no degree of freedom in design.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a projector type headlamp in which the luminous intensity distribution can be arbitrarily set.

[Means for solving problems]

In order to achieve the above object, the projector type headlamp of the present invention has a light source bulb installed near the focal point of the reflector, and the light emitted from the light source is reflected by the reflector to form a shade with a cut line. In a projector-type vehicle headlight that focuses nearby and projects the reflected light forward by a convex lens, the reflective surface of the reflector is divided into a central portion and right and left peripheral portions, (i) the central portion The reflecting surface is configured as an ellipsoid of revolution having a first focal point near the light source bulb and a second focal point near the shade, so that the reflected light is concentrated near the intersection of the shade and the optical axis, and (ii) the above-mentioned The reflective surfaces on the left and right periphery are assumed to have a large number of surface elements constituting the reflective surfaces, and are calculated by subtracting the reflected light from the spheroidal reflective surfaces from the luminous intensity distribution on the shade corresponding to the desired light distribution pattern. A luminous intensity distribution is set, the direction of each surface element is set so that each of the many surface elements reflects the incident light to form the desired luminous intensity distribution, and these many surface elements are assembled to smoothly connect. It is characterized by having been established.

[Effect]

In the headlamp reflector configured as described above, the light reflected by the spheroidal reflecting surface at the center is concentrated near the intersection of the shade and the optical axis, resulting in a central luminous intensity distribution (in the left-right direction). This makes it easier to design the left and right peripheral areas of the reflector (if the remaining light intensity distribution obtained by subtracting the light reflected by the spheroidal reflecting surface from the light intensity distribution on the shade corresponding to the desired light distribution pattern is satisfied) enough). and,
The shapes of the reflective surfaces at the left and right peripheral portions are not constrained to a shape defined by analytical geometry (such as a paraboloid of revolution or an ellipsoid of revolution), as is the case with concave mirrors in the prior art. Since the light distribution characteristics on the shade can be determined and the surface elements of the concave mirror are assembled to form this characteristic, it is possible to configure the light distribution characteristics to any desired light distribution characteristics.

However, the above-mentioned "dividing the reflective surface and assuming surface elements" and "reducing the surface elements of a concave mirror Mi, a, h"
This is a process of dividing and assembling during design thinking, not dividing or assembling actual tangible parts.

The reflective surface to be constructed is, for example, 0.2ml square.
It is almost impossible to divide the surface elements into hundreds of thousands of surface elements and calculate each surface element by its direction and normal direction), but it is almost impossible to calculate it manually using an electronic computer. It's not very difficult.

〔Example〕

Next, before explaining the embodiments of the projector type vehicle headlamp according to the present invention in detail with reference to FIGS. 1 to 11, the present invention will be described with reference to FIGS. 12 to 14. An outline of the arrangement of the constituent parts of one embodiment will be described below.

FIG. 12 is an explanatory diagram schematically depicting a cross section including the optical axis Z and adding an optical path. FIG. 13 is an explanatory diagram in which an optical path is added to a vertical section including the optical axis Z, and FIG. 14 is an explanatory diagram schematically depicting the front as seen from the lens side.

The basic structure of the projector-type automobile headlamp according to the present invention is that the optical axis of a concave mirror and the optical axis of a convex lens are arranged to coincide with each other, and a light source bulb is installed near the focal point of the concave mirror. The light emitted from the light source is reflected by a concave mirror and enters a meridional image plane of a convex lens, and a shade with a cut line is provided near the meridional image plane.

1 is a concave mirror, and F is its focal point. The light source bulb 2 is provided so that the filament is located near the focal point F mentioned above.

A convex lens is provided to share the optical axis Z with the concave mirror 1 described above.

12 indicates the meridional image plane of the convex lens 3, and the light emitted from the light source and reflected by the concave mirror 1 is incident on this meridional image plane.

The above incident light is modulated by the convex lens 3 and is directed forward (
12 and 13).

When a screen is provided near the meridional image plane and the light distribution pattern is shown as an isoluminous curve, it becomes as shown in FIG. 15. HH is a horizontal line on the screen, and ■-■ is also a vertical line. However, FIG. 15 is a general explanation and does not strictly represent the light distribution characteristics.

As shown in FIGS. 12 to 14, a shade 4 having an edge along the meridional image plane is provided. For details, see Part 1.
As shown in 4a in FIG. 4, a cut line is formed so as to recede from the meridional image plane ij. Figure 16 shows
The degree of overlap between the above-mentioned light distribution pattern and the shade 4 is shown. As shown in FIG. 16, the upper half of the luminous flux passes through and most of the lower half is blocked, but the cut line 4a
Light is allowed to pass through the portion corresponding to . However, FIG. 16 is a schematic diagram for explaining the function of the shade, and does not accurately represent the light distribution characteristics.

As the partially covered light beams as described above are focused on the meridional image planes ij and intersect with each other, the light beams projected in front of the headlight have a pattern that is an inversion of the one shown in Fig. 16. form. FIG. 17 is an explanatory diagram showing the general shape of a light projection pattern using isoluminance curves on a screen provided in front of the headlamp.

FIG. 2 is a cross-sectional view showing the design configuration of the reflector 6 in one embodiment of the present invention, and FIG. 1 shows the I-1 cross section. This FIG. 1 is a horizontal cross-sectional view corresponding to FIG. 18 in the above-mentioned known technique, but since it is bilaterally symmetrical, the optical path in the right half is omitted. Further, FIG. 3 shows an m-nr cross section in FIG. 2.

The central portion of the reflecting surface, shown as area C in FIG. 1, is formed into a spheroidal surface with point F as the first focal point and point S as the second focal point. In FIG. 2, the spheroidal surface portion is shown with spots.

Since the central portion C shown in FIG. 1 is configured as a spheroidal surface, the light incident from the light source provided at point F into the area of the spheroidal surface C as shown by arrow 41 is as shown by arrow C.

The light is concentrated at a point St (second focal point placed on the intersection of the shade 4 and the optical axis J-1).

In this way, the light intensity distribution near the center of the shade 4 is increased by the light reflected from the spheroidal surface C, so that the design of the portion other than the spheroidal surface C becomes easier. Specifically, from the desired luminous intensity distribution on the shade, the luminous intensity distribution formed by the reflected light of the spheroidal surface C (concentrated in the center) is subtracted, and the remaining luminous intensity distribution is obtained by subtracting the luminous intensity distribution formed by the light reflected from the spheroidal surface C It may be formed by the part (center part of the reflecting mirror).

As a design method, consider dividing the area other than the above-mentioned spheroidal surface C, that is, the peripheral area D shown in Figure 1 (the part not marked in Figure 2) into a large number of surface elements. .

FIG. 4 is an explanatory diagram schematically depicting the reflective surface 174 of the reflector 6 divided into a large number of surface elements, and FIG. 5 is the optical path of the incident light and reflected light of the surface element Q. It is an explanatory diagram.

The relationship between a point Q on the flapper 6 corresponding to a point S at an arbitrary distance X from the center S1 of the shade 4 is determined (see FIG. 1). That is, the relationship between the set Q of microplane elements located at a distance of Xl from the center T of the reflector 6, -Q-QZ (Fig. 2), is
Find it as follows.

First, when X,=0 as the initial value, the set Q of microsurface elements
! -Q, -Q determine the direction of the surface element (expressed in the normal direction) so that the reflected light reaches the point S.

Set of surface elements Q, -Qb with initial values set as above
Regarding the adjacent portion of Qa, the direction is determined so that the reflected light reaches a portion adjacent to the point SI, and the calculation is repeated in the same manner.

The above x5 and X have a functional relationship x, f (x+). This function is determined based on the desired light distribution on the shade, but specifically, f (x,)=ax, +b f (x,)=ax, 2+bx, +cf (x,)
-a x, 3+b x, "+ c) (,, -L, d
f (XI)=alX1"+a2x,'-'-a11
xl+ag+lf(XL) -21(B b x
Various methods such as + can be considered and can be arbitrarily selected or used in combination. a.

b, c, and d are constants.

A few examples will be described below.

In the case r (x,) = ax, +b, a = 0
．． 5. Assuming that b=o, then f (x+)-0,5XI) (1''' 2. It will be like this.

If the above state is replaced with the relationship between the horizontal cross-sectional shape of the reflector 6 and the meridional image plane (upper edge of the shade), the result will be as shown in FIG. That is, light in two ranges on the reflector 6 side is collected in one range on the meridional image plane, and the light distribution pattern in this case is as shown by the solid line in FIG.

The light reflected by the spheroidal surface C is concentrated near the center and forms the pattern shown by the chain line, and what actually works effectively is the sum of both patterns (the solid line and the chain line).

Under normal usage conditions of automobile headlamps, it is desirable that the luminous intensity in the central portion be concentrated and higher than in the above-mentioned light distribution pattern (FIG. 8).

Therefore, next, f (x+)=a X,"+b x, +c, a
=0.125, b=o, c=0, then f (
x , ) = 0.125x , 2, for example x1 =
4, xs-2 is one of the solutions.

This is expressed on the coordinates as shown in FIG. 9, and the relationship between the reflector and the shade is as shown in FIG. 10. The light distribution characteristics in this case are as shown by the solid line in FIG. 11, and the center luminous intensity is higher than that in FIG. 8 described above.

Although not shown, the above-mentioned high-level function equation, f (
x, )=ax,'+bx,"+cx,+d, and further, f(Xl)=aIxl"atx,-""a,,x++a
As the value of n in .

Desired light distribution characteristics may be obtained by appropriately selecting these equations and arbitrarily selecting constants a, b to d. xl
Since the light intensity distribution characteristics vary widely depending on which order equation is used and the selection of constants, any light intensity distribution characteristics can be obtained within a practical accuracy range.

However, the above ``practical characteristics'' refers to any luminous intensity distribution characteristics within the range of ``a mode in which the luminous intensity is maximum in the center and the luminous intensity decreases symmetrically as it moves away from the center.'' This means that it can also be used.

FIGS. 20 and 21 show an embodiment different from the embodiment shown in FIGS. 12 and 13, and the differences from the previous example are as follows. The shade 4 of the previous example (Figs. 12 and 13) was configured in a cylindrical shape along the meridional image plane i-j, whereas the shade 4 of this example (Figs. 20 and 21)
' is constructed in the shape of a flat plate that is in contact with the meridional image plane i-j and perpendicular to the optical axis Z.

Even with the configuration as in this example, the same effect as the previous example (FIGS. 12 and 13) can be obtained within the accuracy range required for practical use.

〔Effect of the invention〕

As explained above, the projector type headlamp of the present invention can arbitrarily set the luminous intensity distribution on the meridional image plane, and as a result, can be easily configured to have a desired light distribution pattern. It has excellent practical effects.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams of a method of designing a special reflector of the present invention, and FIG. 2 is an explanatory diagram schematically depicting a front view of a beam reflector. Figure 1 is the ■-1 horizontal sectional view, and Figure 3 is the
The figure is the same < mm vertical cross-section. FIG. 4 is an explanatory diagram of a state in which a special reflector according to an embodiment of the present invention is divided into surface elements, and FIG. 5 is an optical path diagram showing the state of reflection in the surface elements. 6 to 11 are explanatory diagrams of a method for designing a reflector according to the present invention. 12 to 14 are explanatory diagrams of the general configuration of a projector type headlamp according to the present invention, in which FIG. 12 is a plan view, FIG. 13 is a side view, and FIG. 14 is a front view. be. FIGS. 15 to 17 are explanatory diagrams of the optical functions of the projector type headlamp. FIG. 18 is an explanatory diagram of a known projector type headlamp.
Figure 9 is a light distribution characteristic chart of the above headlight Σ. FIG. 20 is a plan view of an embodiment different from the above, and FIG. 21 is a side view of the same. DESCRIPTION OF SYMBOLS 1... Concave reflecting mirror, 2... Light source bulb, 3... Convex lens, 4.4'... Shade, 4a... Cut line provided at the upper end of the shade, 5, 6... Reflector. Patent Applicant Ichikoh Industries Co., Ltd. Agent Patent Attorney Tadashi Akimoto Facts 1 Figure〉 Figure 2-x'In Figure 3C Figure 4L Figure 5↑ Figure 6 Figure 7 Figure 8 Figure 8 Figure 9 Figure 10 Figure 13 Figure 14 Y Figure 15 Pro diagram B Figure 8

Claims (1)

[Claims] 1. A light source bulb is installed near the focal point of the reflector, and the light emitted from the light source bulb is reflected by the reflector and focused near the shade having a cut line, and the reflected light is projected forward by a convex lens. In a projector-type headlamp, the reflective surface of the reflector is divided into a central portion and left and right peripheral portions, and (i) the central reflective surface has a first focal point near the light source bulb and a second focal point. It is configured as a spheroidal surface placed near the shade so that the reflected light is concentrated near the intersection of the shade and the optical axis, and (ii) the reflective surfaces at the left and right peripheral portions are composed of a number of surfaces constituting the reflective surface. A desired luminous intensity distribution is set by subtracting the reflected light from the spheroidal reflecting surface from the luminous intensity distribution on the shade corresponding to the desired light distribution pattern, and the numerous surface elements reflect each incident light. A projector-type headlamp characterized in that the direction of each surface element is set so as to reflect and form the desired luminous intensity distribution, and a large number of these surface elements are assembled and smoothly connected.