JPS6035123Y2 - automotive headlights - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an automobile headlamp.

In particular, the present invention relates to an automobile headlamp comprising an inclined front lens, a light source, and a flap that reflects light from the light source toward the lens.

This type of lens is generally configured such that various prisms are formed on the back surface of the lens and the emitted light is controlled by the prism, thereby achieving desired irradiation.

However, in the conventional technology, distortion may occur with respect to the desired light distribution, and uneven light distribution may occur in some areas, resulting in dark zones.

For example, an automobile headlamp in which a cylindrical prism is formed on the back surface of the lens and the surface of the lens 1 is inclined as shown in FIG. 1 uses a so-called C8 type bulb as a light source. If a bulb of the type in which the filament is approximately parallel to the optical axis is used, the light distribution pattern of the irradiation of the passing beam to the front surface will be as shown by diagonal lines in FIG.

In the figure, H is the axis in the horizontal direction, ■ is the axis in the vertical direction,
The ideal pattern is shown by the two-dot chain line.

In other words, in an ideal pattern, the illumination on the right side is directed slightly downward on the horizontal axis H to the extent that it does not dazzle oncoming vehicles, and the illumination on the left side is directed slightly downwards on the horizontal axis H to avoid dazzling oncoming vehicles.・It is necessary to raise the irradiation area sufficiently to the left so that signs, etc. can be clearly seen, but with conventional light distribution patterns, the irradiation area on the right side is too low and the irradiation area on the left side is not sufficient. It does not stand up, and dark zones appear, which are indicated by fine dots.

This is because the lens 1 is tilted upward, so the 21st
As shown in figure A, the light a incident on the center of the cylindrical prism
As shown in Fig. 21B, the incident light is emitted as S'parallel noodle', but the light incident at a position away from the center becomes diagonally downward light b' as shown in Fig. 21C. This is due to the fact that it is emitted.

Note that FIGS. 21B and 21C are views taken in the direction of arrow E in FIG. 21A.

Therefore, as shown schematically in Figure 3, it is not possible to sufficiently illuminate the passerby a on the left side, and the passerby on the right side is hardly illuminated, achieving safe driving. This is a problem.

Note that C in FIG. 3 is the center line.

If the lens 1 is tilted downward in the opposite direction to that shown in FIG. 1, the irradiation area will rise too much on both the left and right sides as shown in FIG. 4 due to the opposite phenomenon, and the irradiation on the right side in particular will be dangerous as it will dazzle oncoming vehicles.

In view of the above circumstances, an object of the present invention is to provide a vehicle headlamp that reduces the dark zone as much as possible and is desirable for safety.

An example of implementing the present invention will be described below with reference to the drawings.

The automobile headlamp of the present invention, as illustrated in FIG.
The lens 1 has an inclined front surface, a light source 2, and a deflector 3 that reflects the light from the light source 2 toward the lens 1.

Therefore, in the present invention, the light source 2 includes the filament 21
．． A bulb 2 as shown in FIG. 6, for example, in which the bulb 22 is substantially parallel to the optical axis is used.

This is a halogen bulb called an 08 type H4/Club.

In the figure, numeral 21 is a subfilament, which is used for a passing beam.

22 is a main filament for the traveling beam.

23 is a light shielding part for preventing the light emitted from the lower part of the reflector 3 from causing upward glare.

Other examples of the C8 type in which the filament is parallel to the optical axis include the incandescent R2 bulb.

Furthermore, in the present invention, the lens 1 includes a prism zone that illuminates an area diagonally above the opposite side of the oncoming lane when the subfilament is turned on, a prism zone that illuminates an area close to the horizon, and a prism zone that illuminates an area below the area close to the horizon. a conical prism or an approximate cone for light distribution control, which is formed of a part of a conical surface or a part of a curved surface approximating a conical surface, in at least one of the prism zones; A prism 4 is formed.

That is, as shown in FIG. 7, a conical prism portion 41 shown by oblique lines in a diagonal grid is formed near the center in the vertical direction on the right side when viewed from the front.

This example is for automobiles in Japan, and the conical prism or approximate conical prism section 41 (the conical prism may be the whole or a part of 41) is provided mainly in the area that controls the area near the horizon on the right side. , is configured to compensate for the right side illumination area.

Due to this prism part 41, the pattern when the sub-filament 21 on the front screen is lit is formed as a part indicated by the reference numeral 52 shown in FIG. decreases.

Further, in the illustrated example, the same conical prism section 4 as described above is also provided to the road half section 42 shown by diagonal lines.

As a result, the light in the area that could not be diffused in the horizontal direction by the prism section 41 is compensated for, and as shown in FIG.
A large diffusion zone 53 is formed below and in the lateral direction, further reducing the dark zone.

Reference numeral 44 in FIG. 7 is a prism portion for controlling light at the rising portion of reference numeral 51 in FIG.
The phenomenon of light drooping on the left side shown in FIG. 2 can be prevented, and the dark zone can be reduced.

In addition, in FIG. 7, the reference numeral 43 is a transparent portion that is used only when the main filament 22 is turned on.

(Although the illustrated lens 1 has a rectangular shape, the same effect can be obtained even if the lens 1 is round or the like by arranging the prism 4 in the same positional relationship.)

As a result, as shown in FIG. 9, both the left side passerby a and the right side passerby can be sufficiently illuminated, and an ideal light distribution can be obtained.

Figures 7 and 8 are examples used when vehicles are driving on the left, as in Japan, but on the other hand, when vehicles are driving on the right,
Using the lens 1 shown in FIG. 10, a pattern as shown in FIG. 11 can be obtained.

The respective symbols are the same as those described above. In addition, the above explanations are for the case where the lens 1 is facing upward as shown in FIG. By arranging the conical prism 4 with different curvatures at both ends upside down from that shown in FIG. 5, it is possible to eliminate the glare.

As mentioned above, according to the present invention, dark zone compensation,
An ideal pattern can be obtained by eliminating glare, etc., and the conical prism or approximate conical prism used for this purpose will be explained below.

Given that it is possible to form a prism with any curved surface and use it for a lens, rigorous calculations must be carried out to avoid distortions in light distribution, such as those that cause dark zones and glare as described above. Such a surface can be defined and used as a prism.

However, in practice, it is easier to handle such a curved surface and to approximate it to a quadratic curved surface, for example, and it is also convenient for actual molding.

Therefore, from this point of view, it is most advantageous to use a conical surface or a curved surface similar to the conical surface as the prism surface, so this is used in the present invention.

The advantage of using a conical surface or an approximate conical surface will be explained below.

First, assuming that it is possible to set a free-form prism (a prism made of an arbitrary curved surface), the prism forming area 4' (the 12th
(see figure) is taken out and enlarged, its prism curved surface is set to 4'', and this is set as a free-form surface, so that any curved surface can be formed.

In other words, let a parallel ray of light horizontally enter the prism surface 4'', and find a point under the boundary condition that the refracted light from the surface of the lens 1 is diffused in the horizontal direction but not in the vertical direction. The curved surface of the prism surface 4'' is determined as a set of such points using, for example, a computer as an optimum value problem.

If obtained in this way, the result will be as shown in FIG. 12.

When the surface of the lens 1 faces upward as in the example of FIG. 5, the upper cross section of the prism 4 is a substantially spherical surface 5' with a small radius of curvature, and the lower cross section is a substantially spherical surface 5'' with a large radius of curvature.

FIG. 13 shows a discretized model obtained by extracting and enlarging one element portion 6 in FIG. 12 when the prism surface 4'' is determined as a set of points.

FIG. 14 shows the model in cross section, and the optical paths are indicated by the same reference numerals.

To explain FIG. 13, X is an axis extending in the horizontal direction when the prism 4 is viewed from the front as shown in FIG.
is a vertical axis, and Z is an axis in the optical axis direction (front-back direction in FIG. 12).

Further, 6A is a surface element of the prism of one element portion 6 taken out arbitrarily, and 6B is a surface element of the lens surface opposite to the surface element 6A.

Let θX1 be the angle between the straight line through which surface element 6A is cut by the Xz plane and the X axis, let θ,1 be the angle between the straight line through which surface element 6A is cut by the YZ plane and the Y axis, and let surface element 6B be cut by the Xz plane. The angle between the straight line and the X axis is θx2,
If the angle between the straight line where surface element 6B is cut on the YZ plane and the Y axis is 07, then 081 and 08° are different angles, θ, □
and 09 are different angles.

In this case, as shown in Fig. 14, when the ray ■ enters the surface element 6A, the refracted ray ■ is obtained from the relationship with the normal ■ of the surface element 6A (Fresnel's law: refractive index = n). is,
From the relationship between the refracted ray (■) and the normal (■) of the surface element 6B (Fresnel's law: refractive index = ), the outgoing ray (■) is obtained.

In this way, if it is possible to take any freely curved surface, the curved surface of the prism can be made up of a collection of points forming a roughly spherical surface whose radius of curvature gradually changes, as shown in Figure 12. Bye.

However, since a simple approximation is required for lens production,
When a continuous curved surface due to such a change in curvature is approximated as a quadratic curved surface, a conical curved surface is considered to be optimal.

That is, as shown in Figure 15a, the conical surface is r□〉r
This is because, as shown in 2, it consists of a circle whose radius decreases continuously from the bottom to the apex.

Therefore, in the present invention, for example, a portion 7 of the conical surface shown in FIG. 15a is taken and used as the prism 4 of the lens 1.

Furthermore, as shown in FIG. 15, it is also possible to use an approximated conical surface in which the generating line of a cone bulges outward with a spherical surface or other curved surface.

This is because when the surface of the lens 1 is not flat but curved, it is optimal to use a prism with a conical surface corresponding to the curved surface.

Even in such a case, any part 7 can be used as a prism.

Either surface can be used as a concave or convex surface.

Next, conditions for actually forming the prism 4 on the back surface of the lens 1 will be explained.

FIG. 16 shows an example of a prism element that can be used in the present invention.

This example is used when the surface 11 of the lens 1 is inclined downward, as shown in FIGS. 22C and 22.

The prism 4 is obtained by cutting a part of the conical surface of the back surface of the lens 1 into a concave shape, and its curvature changes depending on the direction of inclination of the lens 1.

The radius of curvature r3 of the n part in FIG. 16 is the radius of curvature r of the m part,
It has a larger influence than the previous one, and there is a gradual change between the two.

Therefore, in the case of a downward-facing lens, the upper curvature of the prism should be made larger and the lower curvature smaller, and the point should be taken at the deepest part of the curved surface constituting the prism 4, that is, the part near the surface 11 of the lens 1. (concave bottom line)
1□ is parallel to the surface axis 1□ of the surface 11 of the lens 1.

This line 1□ corresponds to the generating line of the cone.

Further, a concave prism is similarly used, but when the lens 1 faces upward, the direction of inclination is reversed, so the relationship of the radius of curvature is also reversed accordingly.

That is, the upper curvature is made smaller and the lower curvature is made larger.

Then, the concave bottom surface line 11 of the curved surface of the prism 4 is the lens 1
The arrangement of the surface 11 parallel to the surface axis 1□ is the same as in FIG.

The optical path when using the interconical prism is shown in the 17th
As shown in the figure and FIG.

In these figures, a indicates the incident light that enters the center of the conical prism, and h and b3 indicate the incident light that enters near both the left and right ends of the conical prism in the same horizontal plane as the incident light a. For convenience, incident light a and b2 and b3 are shown shifted vertically.

) The incident light a that entered the center of the conical prism is refracted upward at 11 points, and then refracted downward at point 01 on the surface of the lens.
′ and is emitted.

In addition, the incident light incident near both ends of the conical prism is diffused to the left and right at points P2 and 13, and is refracted upward at a larger angle than the incident light a at the center of the lens surface Q2. At point Q3), the incident light bzt b3 is refracted downward, and as a result, the incident light bzt b3 is S゛parallel outgoing light r',
It becomes b3' and is emitted.

FIG. 19 shows another embodiment in which the conical prism has a convex shape.

The 0 part in FIG. 19 has a small radius of curvature, and the p part has a conical shape with a large radius of curvature.

Further, the most convex surface line 13 corresponding to the generatrix of the cone is parallel to the surface axis 1° of the surface 11 of the lens 1.

Therefore, when the lens 1 has a surface 11 inclined upward, it is a convex conical prism with a large radius of curvature at the top and a small radius of curvature at the bottom.

Similarly, if the surface 11 of the lens 1 is inclined downward in the conical mortar prism, the most convex surface line 13 of the prism
is parallel to the surface axis 1° of the surface 11 of the lens 1, but the radius of curvature is smaller in the upper part and larger in the lower part.

The optical path when using this conical mortar prism is 20th
As shown in Figure A, Figure 20B, and Figure 20C.

That is, the incident light a that enters the center of the conical prism is refracted upward at points 11 and downward at points 01 on the surface of the lens. ′ and is emitted.

In addition, the incident light incident near both ends of the conical prism,
b3 diffuses left and right at point P2, 13, and
The incident light at the center is refracted upward at a larger angle, and the lens surface Q2. At point Q11), the incident light is refracted downward, and b3 is S゛parallel outgoing light h.
', 1) 11' and is emitted.

Distortion that causes dark zones and dazzling light that are conventionally seen in headlights occurs when the lens surface is inclined with respect to a vertical line when the headlight is attached to the vehicle body.

Therefore, the present invention has a lens 1 whose surface faces upward and is inclined with respect to the vertical line (2), as shown in FIG. 22A,
The opening in the same figure is similar to A, but the surface of the lens 1 is curved with a curvature, the surface of the lens 1 is facing downward, as in C, and the surface is similar to C, as in Figure 2. It can be effectively applied to lenses where the lens 1 is curved, and furthermore, where the surface of the lens 1 is inclined upward and downward as shown in FIG.

In addition, when forming the conical prism 4 of the present invention on the lens 1 shown in Figure 22, the surface of the lens 1 is a curved surface, so the concave bottom line (in the case of a concave prism) The most convex surface line (in the case of a convex prism) uses a conical surface with a bulged surface as shown in Figure 15, and the lens surface 1
Make sure to match it with 1.

In this way, various approximate conical surfaces can be used depending on the shape of the surface 11 of the lens 1.

As described above, the automobile headlamp of the present invention includes a front lens, a light source, and a flap that reflects the light from the light source toward the lens, and the front lens is inclined. In the lamp, the light source uses a filament that is approximately parallel to the optical axis, and the lens includes a prism zone that illuminates an area diagonally above the opposite side of the oncoming lane when the subfilament is turned on, and an area that illuminates an area close to the horizon. and a prism zone that enlarges and irradiates the lower area and the lateral area of the area near the horizontal line, and at least one of the prism zones has a part of a conical surface or a part of a curved surface approximating a conical surface. Since the shape of the cone or cone-approximating prism is made of a cone or a cone-approximating prism, and the generatrix of the cone or cone-approximating prism is made parallel to the surface of the lens, it can be avoided in automobile headlights where the front lens is inclined. This has the effect of correcting distortions in light distribution, bringing it closer to the ideal light distribution pattern, eliminating dark zones, and contributing to safe driving.

[Brief explanation of the drawing]

FIG. 1 is a schematic side cross-sectional view of a conventional example, FIG. 2 is a diagram showing its light distribution pattern, FIG. 3 is a diagram showing the light distribution pattern projected onto the road, and FIG. 4 is another conventional example. FIG. 3 is a diagram showing an example light distribution pattern. 5 is a side sectional view of an example of the implementation of the present invention, FIG. This is a perspective view. FIG. 7 is a front view of the lens of this example, FIG. 8 is a diagram showing the light distribution pattern, and FIG. 9 is a diagram showing the pattern projected onto the road. FIG. 10 is a front view of a lens according to a modification of the above example, and FIG. 11 is a diagram showing its light distribution pattern. FIG. 12 shows a free-form prism, in which A is a front view, the opening is a side sectional view, C and 2 are an upper sectional view and a lower sectional view, respectively. FIG. 13 is a diagram showing a discrete model of the prism element shown in FIG. 12, and FIG. 14 is a cross-sectional view of the same. FIGS. 15a and 15b are perspective views of examples of conical surfaces that can be applied to the prism of the present invention. FIG. 16 is a perspective view showing an example of a prism that can be used in the present invention, FIG. 17 is a perspective view for explaining the optical path when an interconical prism is used, and FIG. 18 is a side view. FIG. 19 is a perspective view of a conical convex prism, FIG. 20A is a perspective view for explaining the optical path thereof, FIG. 20B is a side view, and FIG.
Figure C is also a plan view. FIGS. 21A to 21C are explanatory diagrams showing how the emitted light sag in the conventional example. FIG. 22 is a diagram illustrating the shape of a headlamp to which the present invention can be applied. 1...lens, 2...bulb, 21.
...Sub filament, 22...Main filament, 3...Reflector, 4...
...A cone or a cone-approximating prism.

Claims (1)

[Scope of utility model registration request] An automobile headlamp comprising a front lens, a light source, and a reflector for reflecting light from the light source toward the lens, the front lens being inclined, wherein a filament serving as the light source is approximately parallel to the optical axis. In addition, the lens includes a prism zone that illuminates an area diagonally ahead on the opposite side of the oncoming lane when the subfilament is turned on, a prism zone that illuminates an area close to the horizon, and a lower area near the horizon. At least one of the prism zones is formed with a cone or a cone-approximating prism consisting of a part of a conical surface or a part of a curved surface approximating a conical surface. death,
An automobile headlamp characterized in that the generatrix of the cone or cone-approximating prism is parallel to the surface of the lens.