Vehicular Headlamp Projector Lens with Multi-Mirror Light Redirection
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Solution Overview
Problem
Narrowing the longitudinal width of a projector lens in vehicular headlamps to improve design results in decreased light flux and reduced light incidence on the lens, compromising visibility.
Innovation Solution
A vehicular headlamp design featuring a projector lens with a vertical width narrower than its horizontal width, utilizing a first elliptical reflecting mirror to direct light onto the lens, a second elliptical mirror to reflect non-incident light, and a third parabolic mirror to ensure light is redirected onto the projector lens, maintaining light distribution and preventing excessive brightness on the road surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the vertical width of the projector lens is narrowed to improve design, then the external appearance is improved, but the light flux and amount of light incident on the projector lens are decreased
Solution Approach 1:
The patent divides the light collection and redirection function into multiple separate reflecting mirrors (first, second, and third reflecting mirrors) with distinct roles. The first mirror collects light from the light source, the second mirror redirects light that would otherwise miss the lens, and the third mirror further redirects light to ensure adequate illumination. This segmentation allows each mirror to be optimized for its specific function while collectively solving the problem of maintaining light flux with a narrowed lens width.
Solution Approach 2:
The patent employs multiple reflecting mirrors positioned at different spatial locations and orientations (above, below, and at angles to the optical axis) to redirect light paths in multiple dimensions. By utilizing three-dimensional space for light redirection, the system compensates for the reduced vertical aperture of the narrowed lens, ensuring that sufficient light reaches the lens from various angular directions.
2Shape
If the upper and lower portions of the projector lens are cut out by a predetermined amount, then the design is improved, but the amount of light incident on the projector lens is reduced
Solution Approach 1:
The patent introduces reflecting mirrors as intermediary elements between the light source and the projector lens. These mirrors act as mediators that capture light rays that would otherwise be blocked or miss the lens due to the cut-out portions, and redirect them onto the lens surface. The second and third reflecting mirrors specifically serve as intermediaries to redirect light from alternative paths, ensuring the lens receives adequate illumination despite its modified shape.
Solution Approach 2:
The patent changes the geometric parameters of the light path by introducing reflecting surfaces with specific shapes (elliptical and parabolic) and orientations. By adjusting the positions, angles, and curvatures of the reflecting mirrors, the system modifies how light rays traverse the optical path, enabling light to reach the lens through redirected paths that compensate for the reduced effective area caused by the cut-out portions.
3Illumination intensity
If multiple reflecting mirrors are added to maintain light flux, then the light amount is secured, but the device complexity increases
Solution Approach 1:
The patent combines multiple reflecting mirrors into a unified optical system where each mirror serves a specific but complementary function. The first, second, and third reflecting mirrors are integrated to work together as a cohesive light management system, with their combined effect achieving the desired illumination level. This merging approach allows the complex function of light redirection to be distributed across specialized components rather than requiring a single complex element.
Solution Approach 2:
The patent employs curved reflecting surfaces (elliptical and parabolic shapes) for the reflecting mirrors. These curved geometries are highly effective at redirecting light rays from various angles onto the projector lens, maximizing light collection efficiency. The use of mathematically optimal curved surfaces allows each mirror to perform its light redirection function with high efficiency, reducing the need for additional mirrors and thereby moderating the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration secures the same amount of light as a standard projector lens, even when the upper and lower portions of the projector lens are cut out, while preventing excessive brightness on the road surface, thus maintaining visibility and design aesthetics.
Implementation Method 1
a first reflecting mirror (14) having an elliptical reflective surface that reflects light emitted from the light source
Implementation Method 2
a second reflecting mirror (16) disposed to reflect light which is emitted from the light source and is not incident on the first reflecting mirror
Implementation Method 3
a third reflecting mirror (18) disposed above the upper end of the shield plate at a position that does not interfere with the light reflected from the first reflecting mirror, and reflecting the light reflected from the second reflecting mirror toward the projector lens
Implementation Method 4
a projector lens (24) having a shape where a vertical width is narrower than a horizontal width
Data Source
AI summary
A projector lens of a vehicular headlamp has a shape of a convex lens in which the upper and lower portions are cut by a predetermined amount. A light source is disposed above optical axis Ax of the projector lens while a light emission surface is inclined downwardly. A first reflecting mirror has an elliptical reflective surface, and is adjusted in size such that almost all the light reflected from the reflective surface is incident on the projector lens. A shield plate is disposed in the vicinity of the focus of the first reflecting mirror to form a horizontal cutoff line. A second reflecting mirror is disposed to reflect light that is not incident on the first reflecting mirror. The third reflecting mirror is disposed above the upper end of the shield plate at a position that does not interfere with the light reflected from the first reflecting mirror.