JPS6035124Y2 - 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 is used as a light source.
When six types of bulbs are used, that is, the type of bulb in which the filament is substantially perpendicular to the optical axis, the light distribution pattern of the irradiation of the passing beam to the front surface becomes 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 of the horizontal axis H so as not to dazzle oncoming vehicles, and the illumination on the left side is directed slightly below the horizontal axis H to avoid dazzling oncoming vehicles. - It is necessary to illuminate above the horizon to ensure that signs, etc. can be seen, but with conventional light distribution patterns, the illumination area on the right side is too low and the illumination area on the left side is also insufficient. However, dark zones, each marked with a fine dot, appear.

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

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

Therefore, as shown schematically in Figure 3, the passerby on the left cannot be sufficiently illuminated, and the passerby on the right can hardly be illuminated, making it difficult to drive safely. This is a problem when it comes to relationships.

In addition, in FIG. 3, C 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.

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

Hereinafter, an example of the implementation of the present invention will be described with reference to the drawings.

The automobile headlamp of the present invention, as illustrated in FIG.
It comprises a lens 1 with 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
．． For example, a bulb 2 as shown in FIG. 6, in which the bulb 22 is substantially perpendicular to the optical axis, is used.

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

22 is a main filament for the traveling beam.

23 is a light shielding portion for preventing upward dazzling light.

Other examples of bulbs or bulbs in which the filament is perpendicular to the optical axis include incandescent C6 and general sealed beam types.

Furthermore, in the present invention, when the subfilament is turned on, the lens 1 has a prism zone that illuminates the diagonally forward area on the opposite side of the oncoming lane, and a prism zone that illuminates the area closer to the horizon than the area closer to the horizon. A conical prism or approximate conical prism 4 for light distribution control, which is made of a part of a conical surface or a part of a curved surface approximating a conical surface, is formed in the prism zone that irradiates the light.

In the illustrated example, as shown in FIG. 7, prism parts 41 and 41' are provided with conical prisms or approximate conical prisms 4 at the left and lower right parts when viewed from the front (the conical prism is the part 41.41'). (may be the whole or a part) to compensate for the irradiation area on the right side.

That is, this example is for automobiles in Japan, and due to the prism portions 41 and 41', the pattern when the sub-filament 21 on the front screen is lit is shown in Fig. 8 with reference numeral 5.
A diffused part shown in 2 is formed, which leads to the H on the right side.
Areas close to the line are illuminated, reducing dark zones.

In addition, in the illustrated example, the same conical prism or approximate conical prism 4 as described above is provided to the right side upper side portion 42a, the right side portion 42b1 below it, and the left side lower side portion 42c and the left side portion 42d above it. It is.

Thereby, it is possible to prevent the hot zone from sagging and form the hot zone indicated by reference numeral 51 at an appropriate position in cooperation with the prism portions 41, 41', as shown in FIG.

In FIG. 7, 43 is a transparent portion.

Although the illustrated lens 1 has a rectangular shape, the prism 4 can be formed in a round shape or other shape in a similar positional relationship to obtain the same effect.

- As a result of this configuration, as shown in FIG. 9, both the left-hand pedestrian a and the right-hand pedestrian a can be sufficiently illuminated, and an ideal light distribution can be obtained.

Figures 7 and 8 are examples that are used when vehicles are driving on the left, as in Japan, but on the other hand, when vehicles are driving on the right,
By using the lens 1 shown in FIG. 10, which is symmetrical with respect to FIG. 7, a pattern as shown in FIG. 11 can be obtained.

Each reference numeral is the same as in the above description.

In addition, the above examples are all for the case where the lens 1 is facing upward as shown in FIG. 5, but when the lens 1 is facing downward, FIG.
Prism portions 41° 41', 42a to 42d shown in Figure 0
By arranging different curvatures at both ends of the conical prism or approximate conical prism to be applied in the opposite manner to that shown in FIG. 5, the dazzling light can be eliminated.

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

Given that any curved surface can be formed into a prism and used as a lens, it is necessary to carry out rigorous calculations to avoid distortions in light distribution, such as distortions in light distribution that may cause dark zones or dazzling light at the front. Such a surface can be defined and used as a prism.

However, in practice, it is easier to handle a curved surface that is simpler than such a curved surface, such as a quadratic curved surface, 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 taken.

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 lens 1 is facing upward as in the example in the 5th column,
The upper cross section of the prism 4 is a substantially spherical surface 5' with a small radius of curvature;
The lower cross section becomes a substantially spherical surface 5'' with a large radius of curvature.

FIG. 13 shows a discretization model in which one element portion 6 in FIG. 7 is taken out and enlarged 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, as shown in FIG. 12, X is an axis extending in the horizontal direction when the prism 4 is viewed from the front.
Y is a vertical axis, and Z is an axis in the optical axis direction (front-back direction in FIG. 12).

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

Also, let θX1 be the angle between the straight line through which the surface element 6A is cut by the xZ plane and the X axis, θy1 be the angle between the straight line through which the surface element 6A is cut by the yzy plane and the Y axis, and let the angle between the straight line through which the surface element 6A is cut by the yzy plane and the Y axis be θy1. The angle between the straight line and the X axis is θ
~, If the angle between the straight line through which surface element 6B is cut on the YZ plane and the Y axis is θy, then an angle different from θX1θX2, θ
y□ and θy are different angles.

When this is done, as shown in FIG.
Fresnel's law: Refracted ray ■ is obtained from the refractive index = n), and the outgoing ray ■ is obtained from the relationship between the refracted ray ■ and the normal ■ of surface element 6B (Fresnel's law: refractive index = 1/n) .

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. Good.

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 optimal.

This is because, as shown in FIG. 15a, the conical surface has a circumference whose radius decreases continuously from the base to the apex, as shown by r□>r2.

Therefore, in the present invention, for example, a part 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.

An example of this is shown in Fig. 22c. As shown in Fig. 2, it is used when the surface 11 of the lens 1 is tilted downward.

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 r4 of the m part.
It is formed larger than the previous one, and there is a gradual change between the two.

Therefore, when using the downward lens 1, the upper curvature of the prism is made larger and the lower curvature is made smaller, and the prism 4
A line obtained by taking the points at the deepest part of the curved surface that makes up the surface, that is, the part close to the surface 11 of the lens 1 (the most concave bottom line) 1□
is parallel to the surface axis 1° of the surface 11 of the lens 1.

This line 11 corresponds to the generating line of the cone.

Similarly, a concave prism is used, but if the lens 1 is tilted upward, the direction of tilt is reversed, and the relationship between the radii 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
is parallel to the surface axis 1□ of the surface 11 as in FIG. 16.

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, the incident lights a, bl, and b3 are shown shifted vertically).

The incident light a that enters the center of the conical prism is refracted upward at 10 points, and is refracted downward at the 1 point on the surface of the lens, resulting in an output light a parallel to the incident light a.
′ and is emitted.

Also, the incident light incident near both ends of the conical prism,
t4 is P2. At P3, it spreads left and right, and
It is refracted upward at a larger angle than the incident light Aa at the center, and refracted downward at point Q2.03 on the surface of the lens, and as a result, the incident light b3 is S゛parallel outgoing light b2'9 b3 ' and is emitted.

FIG. 19 shows another embodiment in which the conical prism is formed into a convex shape.

The 0 part in FIG. 19 is formed into a conical surface with a small radius of curvature, and the p part is formed into a conical surface with a large radius of curvature.

Further, the crotch 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 an upwardly inclined surface, 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 a convex prism and is inclined downward, 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 curvature changes. is smaller at the top and larger at the bottom, corresponding to the slope.

The optical path when using this conical convex 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 the incident light a becomes parallel outgoing light a. ′ and is emitted.

In addition, the incident light incident near both ends of the conical prism, b
3 is diffused to the left and right at point P2, 43, and is refracted upward at a larger angle than the incident light at the center,
At point Q2.03 on the surface of the lens), the incident light is refracted downward, and as a result, b3 is S゛ parallel outgoing light h
', b3' and is emitted.

Distortion, which causes dark zones 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 is oriented upward and inclined with respect to the vertical line V, as shown in FIG.
As shown in the figure 2, it is similar to A, but the surface of the lens 1 is curved with a curvature, as shown in the same figure, the surface of the lens 1 is facing downward, and as shown in Figure 2, it is similar to C. Lenses with curved surfaces, as shown in the figure (E),
It can be effectively applied to objects whose surfaces are sloped upward and downward.

Further, when forming the conical prism 4 of the present invention on the lens 1 as shown in Figure 22, the surface 1 of the lens 1
Since 1 is a curved surface, the bottom line of the crotch (in the case of a concave prism) and the most convex surface line (in the case of a convex prism) are conical surfaces with bulges as shown in Figure 15, and the lens surface Match it with 11.

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 perpendicular to the optical axis, and the lens has a prism zone that illuminates the diagonally forward area on the opposite side of the oncoming lane when the subfilament is turned on, and a prism zone that illuminates the area near the horizon. 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 is formed in a prism zone that illuminates at least a region below the horizontal line among the prism zones that illuminate the downward direction, and Since the generatrix of the cone or cone-approximating prism is made parallel to the surface of the lens, it corrects the distortion of light distribution that cannot be avoided in automobile headlamps with inclined front lenses, making it ideal. This has the effect of bringing the light distribution pattern closer to the light distribution pattern, eliminating the dark zone, and contributing to safe driving.

[Brief explanation of drawings]

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. FIG. 5 is a side sectional view of an example of the implementation of the present invention, FIG. It is an arrow 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. FIG. 21A to FIG. 21C are explanatory diagrams showing the dripping of emitted light in the conventional example. FIG. 22 is a diagram illustrating the shape of a headlamp to which the present invention can be applied.

Claims (1)

[Scope of utility model registration request] In 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 is inclined, and the filament as the light source is approximately parallel to the optical axis. In addition to using right angles,
The lens has a prism zone that illuminates an area diagonally ahead on the opposite side of the oncoming lane when the subfilament is turned on, and a prism zone that illuminates an area closer to the horizon than an area closer to the horizon, at least a prism zone that illuminates an area closer to the horizon. , forming 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, and
An automobile headlamp characterized in that the generatrix of the cone or cone-approximating prism is parallel to the surface of the lens.