JPH0249602Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a lens for headlights used in automobiles, etc. Specifically, the invention relates to a lens for headlights used in automobiles, etc., and more specifically, a front opening of a concave mirror (reflector) with a light source bulb installed near the focal point. This relates to a prism lens that is worn over the entire body.

[Prior art]

Automobile headlights must be able to brightly illuminate the area in front of the vehicle's lane, and must not dazzle oncoming vehicles.

For this reason, a headlamp is generally configured so that a beam of light emitted from a light source bulb and reflected substantially parallel by a reflector is diffused by a prism lens to obtain a desired light distribution pattern.

The prism lens described above has its lens surface divided into a plurality of areas, and each area shares part of the desired light distribution pattern.

FIG. 6 is a front view of a conventional prism lens, in which the area is a segment for large diffusion, the area is a segment for a horizontal cut and a hot zone of a passing beam, and the area is a segment for a 15° cut and a hot zone of a passing beam. Then,
The area closer to the oncoming lane than the center of the lens surface is a segment in which prisms are arranged to dim the light beam illuminating the road shoulder of the self-driving lane.

The light beam passing through this area on the prism lens surface corresponds to zone 4 shown by hatching in FIG. 7 when shown in correspondence with the emission pattern from the reflector.

The prism in the above area refracts and diffuses the reflected light beam in zone 4 so as to tilt it upward by about 2 degrees and to the left by about 4 degrees, and is shown in the light distribution pattern in Figure 8 with hatching. 4', which mainly serves to illuminate the shoulder of the vehicle lane.

A conventional prism lens configured to have the above-described function is shown in FIG. 9 in cross section, and in FIG. 10 in vertical cross section.

In FIG. 9, P indicates the arrangement pitch of the prism elements, T indicates the reference thickness of the prism lens, and r _x indicates the radius of the cylindrical prism.

In order to provide the above function, the prism lens of this conventional example has a horizontal prism angle φ _x of 10 degrees (see FIG. 9) and a vertical prism angle φ _y of 2 degrees (see FIG. 10). is set to .

[Problem that the invention attempts to solve]

As is clear from FIG. 9, a planar prism riser is formed by providing a horizontal prism angle of φ _x . Therefore, the light incident on the riser as indicated by arrow a is refracted as indicated by arrow b and emitted as indicated by arrow c, resulting in an undesirable light distribution characteristic factor as indicated by 5 in FIG.

Further, as is clear from FIG. 10, the step 2 is formed by providing the prism angle φ _y in the vertical direction. For this reason, molding of prism lenses becomes difficult and the defective rate is high. Naturally, therefore, the cost will be high.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to use diffused light to illuminate the vicinity of the road shoulder of the self-driving lane without the need to provide a prism angle (even if the prism angle is 0°). To provide a lens for a headlamp, which can uniformly irradiate light, can effectively use the light incident on a prism element, and is free from the risk of producing harmful glare.

[Means for solving problems]

The present invention, which was created to achieve the above object, is a prism lens that is attached to the front opening of a concave mirror with a light source bulb near the focal point. A headlight comprising at least one of a substantially vertical cylindrical prism element and a conical prism element arranged in a substantially horizontal direction in order to diffuse a light flux to illuminate the vicinity of the road shoulder on the vehicle lane side. Each of the prism elements arranged in a row has an inclination angle with respect to the vertical direction, and the prism element closest to the center of the lens surface among the prism elements arranged in a row is The inclination angle is made the smallest, and the inclination angle is increased by a certain minute angle as it approaches the left and right ends of the lens surface, and the inclination angles of the prism elements in the portions that occupy more than half of the area are arranged in an arithmetic series. It is something.

However, the above-mentioned constant minute angle is a constant angle of several degrees or less.

[Effect]

According to the above configuration, a certain minute angle (e.g.
By using prism elements that vary the inclination angle in steps of 1°), the road shoulder can be illuminated with uniform diffused light, and there is no need to set a prism angle.

〔Example〕

FIG. 2 shows an embodiment of the headlamp lens of the present invention. This embodiment is an example in which the present invention is applied to improve the conventional example shown in FIG. 6, and the areas with the same drawing reference numbers as in FIG. are similar components.

The area is a segment constructed by applying the present invention, and its enlarged details are shown in FIG.

Prism elements 6 _-1 , 6 _{-2 , 6 - 2 , 6 - 2} are arranged in rows on the left and right and each have a substantially vertical cylindrical surface, starting from the one closest to the center of the lens surface.
Name it 6 _-9 . Then, the inclination angles of these prism elements with respect to the vertical line are θ ₆ , θ ₇ to _{θ 13} , respectively.
Name them θ ₁₃ ′ and θ ₁₃ ″.

In this example, θ ₆ =6°.

Starting from θ ₆ , the inclination angle is increased by 1° in sequence, such as θ ₇ = 7°, θ ₈ = 8°, and θ ₉ = 9°.

θ ₁₃ =θ ₁₃ ′=θ ₁₃ ″=13°. In this way, it is possible to provide a location where prism elements having the same inclination angle are arranged in a row.

In this example, neither the upper and lower prism angles nor the left and right prism angles are provided (the prism angle is set to 0).

3A shows a cross section taken along the line AA in FIG. 1, and FIG. 3B similarly shows a cross section taken along the line BB.

It is obvious that if the prism angle is not provided in this way, the prism lens can be easily molded and the cost can be reduced. Even if no prism angle is provided, the inclination angle of each prism element is sequentially changed, so that the light flux passing through this area is uniformly dispersed and illuminates the road shoulder of the self-driving lane. FIG. 4 is an explanatory diagram of the light distribution pattern in this example. The closed curve drawn with a chain line indicates the outline of the light distribution pattern, and the many closed curves drawn with solid lines indicate the irradiation zone of the light flux scattered by each prism element. It shows.

In this way, all the light incident on the area (FIG. 2) is effectively utilized to form the desired light distribution pattern without creating harmful glare.

FIG. 5 shows a different embodiment from the above, in which the area '' is set larger than that of the previous example (FIG. 2).
Even with this configuration, the same effect as the previous example can be obtained.

[Effect of idea]

As detailed above, according to the headlight lens of the present invention, the road shoulder of the self-driving lane can be illuminated with uniform diffused light without providing a prism angle.
High efficiency of luminous flux and no harmful glare.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged front view of a prism lens according to an embodiment of the present invention, and FIG. 2 is a front view of the entire prism lens. Figure 3A is a sectional view taken along line A-A in Figure 1;
FIG. 3B is a sectional view taken along line B-B. FIG. 4 is an explanatory diagram of the light distribution pattern in the above embodiment, and FIG.
The figure is a front view of an embodiment different from the above. FIG. 6 is a front view of the conventional example, and FIGS. 7 and 8 are functional explanatory diagrams of the conventional example. FIGS. 9 and 10 are sectional views of the conventional example. 1... Prism riser, 2... Step, 6 _-1 ~ 6
_-9 ... Prism element, θ ₆ ~ _{θ 13} , θ ₁₃ ′, θ ₁₃ ″...
Tilt angle of prism element, T...Reference thickness of prism lens, P...Arrangement pitch of prism element, φ _x
...Left and right prism angles, φ _y ...Upper and lower prism angles.

Claims (1)

[Scope of utility model registration request] It is a prism lens that is attached to the front opening of a concave mirror with a light source bulb near the focal point, and it diffuses the light beam that should illuminate the road shoulder area on the driver's lane side to an area closer to the oncoming lane than the center of the lens surface. In a headlamp lens comprising at least one of a substantially vertical cylindrical prism element and a conical prism element arranged in a substantially horizontal direction, each of the arranged prism elements has an inclination angle with respect to the vertical direction, and the prism element closest to the center of the lens surface among the arranged prism elements has the smallest inclination angle, and the inclination angle decreases as it approaches the left and right ends of the lens surface. 1. A headlamp lens characterized in that the inclination angle of the prism element is arranged in an arithmetic progression in a portion that occupies more than half of the area, with the prism element increasing by one constant minute angle.