JPS62190603A - 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 vehicle's own lane and does not dazzle 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 elliptical part 101.102 of every axial section is also the corresponding vertex 104 of the elliptical part 101.102 of every axial section.
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.

FIG. 20 is an isoluminance curve chart when a screen is placed in front of the projector-type headlamp of the above-mentioned known example and irradiation is performed. As is clear from this diagram, this light distribution pattern has insufficient spread in the left and right directions (projection light in directions of 20 degrees to the left and right is zero).

The present invention has been made in view of the above-mentioned circumstances, and it is possible to set the luminous intensity distribution arbitrarily, obtain a light distribution pattern with a wide spread from side to side, and effectively utilize the light emitted from the light source. The present invention aims to provide a projector-type headlamp with a high efficiency.

[Means for solving problems]

In order to achieve the above object, the projector-type headlamp of the present invention has a light source pulp installed near the focal point of a 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 using a convex lens, the reflective surface of the reflector is divided into a central portion, left and right peripheral portions, and an intermediate portion between the two. i) The reflective surfaces of the left and right peripheral portions are spheroidal surfaces with a first focal point near the light source pulp and a second focal point near the shade,
It is configured so that the reflected light is concentrated near the intersection of the shade and the optical axis, and the reflective surface at the center of the 6D is designed to form a desired light distribution pattern while assuming a large number of surface elements 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 corresponding shade, and the plurality of surface elements reflect each incident light to form the desired luminous intensity distribution. The direction of each surface element is set in , and a large number of these surface elements are assembled and connected smoothly, and the reflective surface at the center of the QiO is formed so that its horizontal cross section forms a parabola with its focus near the light source pulp. It is characterized by being configured as follows.

[Effect]

In the headlamp reflector configured as described above, the light reflected by the spheroidal reflecting surface on the periphery is concentrated near the intersection of the shade and the optical axis, resulting in a central luminous intensity distribution (in the left-right direction). Since it is raised, the design around the middle part of the reflector becomes easier. The shape of the reflecting surface at the intermediate portion is not limited to a shape determined by analytical geometry (for example, a paraboloid of revolution or an ellipsoid of revolution), as is the case with concave mirrors in the prior art. The light distribution characteristic on the shade can be determined and the surface elements of the concave mirror can be assembled to form this characteristic, so that the light distribution characteristic can be configured to any desired value.

However, the above-mentioned "dividing the reflective surface and assuming surface elements" and "assembling the surface elements of a concave mirror" are division 1 assembly during design thinking, and dividing the actual tangible members. It's not something you have to do or assemble.

It is possible to divide the reflective surface to be constructed into hundreds of thousands of surface elements of, for example, 0.2 squares, and calculate the direction (represented by the normal direction) for each surface element. , which is nearly impossible to calculate manually, but is not difficult to do using an electronic computer.

Further, since the parabolic reflecting surface at the center reflects the light beam almost in parallel in the direction of the optical axis, when this parallel light beam is modulated by the front lens, a light distribution pattern with a wide spread left and right can be obtained.

〔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 2 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.

■ 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.
The cut line is formed so as to recede from the meridional image plane ij, as shown in 4a shown in Fig. 4. In Fig. 16,
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. In addition, the cross section of FIG. 2 is shown in FIG. 3.

The left and right peripheral portions shown as area C in FIGS. 1 and 2 are formed into spheroidal surfaces 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 left and right peripheral portions C shown in FIG.

The light incident on the area C of the ellipsoid of revolution, like the mouth, is concentrated at a point S, as shown by the arrow C and 2 (a second focal point placed on the intersection of the shade 4 and the optical axis T1).

The central area shown as area A in Figures 1 and 2 is point F.
It is composed of a paraboloid of revolution with the focal point.

When carrying out the present invention, the central portion A is constructed so that at least its horizontal cross section forms a parabola. The vertical cross-sectional shape may be a parabola, or the intermediate portion B described later
It is also possible to create a modified shape by applying the design method described above.

In FIG. 2, the parabolic area is shaded with parallel hatching.

Since the horizontal section of the central portion A shown in FIG. 1 forms a parabola, the light incident from the focal point F as indicated by the arrow H is reflected parallel to the optical axis JJ as indicated by the arrow.

In this way, the light intensity distribution near the center of the shade 4 increases due to the reflected light from the spheroidal reflecting surface C, and
Since the reflected light from the parabolic reflecting surface A is distributed to the periphery of the shade 4, the area B other than the areas C and A mentioned above is
design becomes easier.

Specifically, from the desired luminous intensity distribution on the shade,
rThe luminous intensity distribution formed by the reflected light of the spheroid C (concentrated in the center) and the luminous intensity distribution formed by the reflected light of the parabolic part A (spread to the periphery). The remaining luminous intensity distribution may be formed by portions other than C2A.

As a design method, consider dividing the intermediate portion B shown in FIG. 1 (the portion without spots or parallel hatching in FIG. 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 an arbitrary distance X5 point S from the center Sl of the shade is determined (see FIG. 1).

That is, from the center T of the reflector 6 to X.

The set of microsurface elements QI Q Q2 (second
The relationship shown in Figure) is determined as follows.

First, when x1=0 as the initial value, the set Q of microsurface elements
, -T-Q, determine the direction of the surface element (expressed in the normal direction) so that the reflected light reaches the point S.

A set of surface elements Q, −T−Q, whose initial values are set as above,
Regarding the adjacent portion, the direction is determined so that the reflected light reaches the adjacent portion of the point S, and the calculation is repeated in the same manner.

The above-mentioned X and xl have a functional relationship, and X= r (x+). This function is determined based on the desired light distribution on the shade, but specifically, f (x,)=ax, +b r (x,)=ax, "+bx," +cf (x,)
=ax,'+bx-+cx,+dr (x,)=a,
x,'+azx−-'°”anXI+an+1f (
Various methods such as x, )=ae"' 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 of r (x 1 ) = a x, 1 + b, assuming a = 0.5 and b = o, f (x+) = o, s XI, and x, = 2. xt=1 is one of the solutions. When this is expressed on a coordinate plane, it becomes as shown in FIG.

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 above-mentioned spheroidal surface C is concentrated near the center, forming a pattern shown by the chain line, and the light reflected by the parabolic reflecting surface has a diameter that extends to the periphery, as shown by the dotted line. What actually works effectively is the sum of the above three patterns (solid line, chain line, and dotted 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,)=ax
, "+bx, a = 0.125, b = o in ten c,
Assuming c=o, f (x+)=0.125x+
”, and for example, x1=4 and xs='l are 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,'I+bx,"+cx,+d, and further, f(x+) = a + X +'"+a2X l"-
As the value of n in ``a 6

Desired light distribution characteristics may be obtained by appropriately selecting these equations and arbitrarily selecting constants a, b to d. X,
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.

21 and 22 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. 21 and 22)
' 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.

Reference numeral 114 indicated by a chain line in FIG. 1 indicates a spheroidal reflecting surface in the prior art for comparison. As is clear from comparing this with the reflective surface 1 of this example, if the present invention is applied and appropriately designed, the optical performance will be improved, and
The dimension of the headlight in the optical axis direction can be shortened (the depth of the reflector can be reduced).

〔Effect of the invention〕

As explained above, in the projector type headlamp of the present invention, the light intensity distribution on the meridional image plane can be arbitrarily set, and as a result, a desired light distribution pattern can be easily obtained.
In particular, it has an excellent practical effect in that it can be constructed so that the central luminous intensity is high and the peripheral luminous intensity is wide spread.

[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 I-1 horizontal sectional view, Figure 3
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.
9 and 20 are light distribution characteristic charts of the headlight. FIG. 21 is a plan view of an embodiment different from the above, and FIG. 22 is a side view of the same. ■...Concave reflecting mirror, 2...Light source bulb, 3...Convex lens, 4.4'...Shade, 4a...Cut line provided at the upper end of the shade, 6...Reflector. Patent applicant Masami Akimoto, agent of Ichikoh Industries, Ltd., patent attorney! ! Figure 1 Figure 2 Figure 3 Figure 4 L Figure 5 Figure 6 Figure 7 Figure 8 Likelihood Figure 9 Figure 16 Figure 8 Figure 19 To mourning C:! 11. −

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, left and right peripheral portions, and an intermediate portion between the two, and (i) the reflective surface of the left and right peripheral portions has a first focal point near the light source bulb. and a second focal point near the shade as an ellipsoid of revolution, so that the reflected light is concentrated near the intersection of the shade and the optical axis,
(ii) The reflecting surface in the intermediate portion assumes a large number of surface elements constituting the reflecting surface, and the reflected light from the spheroidal reflecting surface is calculated based on the luminous intensity distribution on the shade corresponding to the desired light distribution pattern. The subtracted desired luminous intensity distribution is set, the direction of each surface element is set so that each of the plurality of surface elements reflects the respective incident light to form the desired luminous intensity distribution, and these many surface elements are assembled. smoothly connected, and (iii)
The projector-type headlamp is characterized in that the central reflecting surface is configured such that its horizontal cross section forms a parabola with a focus near the light source bulb.