Vehicle lamp lens

A vehicle lamp lens includes a base wall and a light output wall. The base wall has a light input surface, and a base surface disposed in front of the light input surface, and having a plurality of parabolic base sections. The light output wall extends forwardly from a front end of the base wall, and has an inner surface, an outer surface, and a light output surface connected between front ends of the inner and outer surfaces. The outer surface is formed with a plurality of microstructures disposed proximate to the base wall. Each of the micro structures has a parabolic first surface portion having a first virtual focus. The first virtual focuses of the first surface portions of the microstructures are located at the same point.

FIELD

The disclosure relates to a lamp lens, and more particularly to a vehicle lamp lens which is disposed for transmitting a light that is emitted from a light emitting member.

BACKGROUND

A conventional vehicle lamp includes a light emitting member, and a vehicle lamp lens disposed to transmit light that is emitted from the light emitting member. The vehicle lamp lens has a light incident surface, a reflecting surface and a light output surface. With such disposition, the light that enters the conventional vehicle lamp lens will exit the conventional vehicle lamp lens through the light output surface after undergoing a total internal reflection (TIR) by the reflecting surface. In order to acquire a better light transmitting efficiency, it is necessary to improve the disposition of each of the surfaces of the conventional vehicle lamp lens.

SUMMARY

Therefore, the object of the disclosure is to provide a vehicle lamp lens that has an innovative structure, and that has good light transmitting efficiency.

According to the disclosure, the vehicle lamp lens is adapted to transmit light that is emitted from a light emitting member, and includes a base wall and a light output wall. The base wall has a light input surface adapted to face the light emitting member, and centered at an optical axis which is parallel to a front-rear direction, and a base surface centered at the optical axis, disposed in front of the light input surface for reflecting the light which is propagated from the light input surface, and having a plurality of parabolic base sections. The light output wall extends forwardly from a front end of the base wall, cooperates with the base wall to define a lens space, and has an inner surface, an outer surface disposed opposite to the inner surface, and a light output surface connected between front ends of the inner and outer surfaces. The outer surface is formed with a plurality of microstructures disposed proximate to the base wall for reflecting the light, which is reflected from the base surface, toward the light output surface. Each of the microstructures has a parabolic first surface portion having a first virtual focus. The first virtual focuses of the first surface portions of the microstructures are located at the same point.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 3, the embodiment of a vehicle lamp lens according to the disclosure is adapted to transmit light that is emitted from a light emitting member1. The light emitting member1may be a light-emitting diode (LED). The vehicle lamp lens and the light emitting member1cooperately form a vehicle lamp, and may be configured as a head lamp, a daytime running light (DRL), a front turn signal, a rear turn signal and a brake light. The vehicle lamp lens has a base wall2and a light output wall3.

The base wall2has a light input portion21, and an extending portion22connected to the light input portion21. The light input portion21has a light input surface211adapted to face the light emitting member1, and centered at an optical axis (L) which is parallel to a front-rear direction, and a base surface212centered at the optical axis (L), disposed in front of the light input surface211. The base surface212has a plurality of parabolic base sections213disposed for reflecting the light which is propagated from the light input surface211. It should be noted that, since light beams reflected by a parabolic surface may be parallel to each other, and are further transmitted in a certain direction, in other embodiments, the base sections213may cooperate with other types of optical structure to acquire the better light emitting efficiency.

The light output wall3extends forwardly from a front end of the base wall2, and cooperates with the base wall2to define a lens space30.

The light output wall3is polygonal-shaped, and has an inner surface31, an outer surface32disposed opposite to the inner surface31, and a light output surface33connected between front ends of the inner and outer surfaces31,32. The outer surface32is formed with a plurality of microstructures34disposed proximate to the base wall2. The microstructures34are juxtaposed along a periphery of a rear end of the outer surface32, and are disposed for reflecting the light, which is reflected from the base surface212, toward the light output surface33. Each of the microstructures34has a parabolic first surface portion341, and a second surface portion342connected to the first surface portion341. The first surface portions341cooperately form a multiple parabolic surface structure. The first surface portion341of each of the microstructures34is connected to the second surface portion342of an adjacent one of the microstructures34. The outer surface32has a smooth surface portion35disposed in front of the microstructures34. Where the outer surface32is not formed with the microstructures34is the smooth surface portion35. The light output surface33is formed with a plurality of diffusing structures331protruding forwardly, and disposed for uniforming light passing therethrough. It should be noted that, in other embodiments, the diffusing structures331may be omitted.

Referring toFIGS. 1, 3 and 4, the light emitting member1is centered at the optical axis (L), and is disposed behind a central portion of the light input surface211of the base wall2. Light beams emitted from the light emitting member1firstly enter into the base wall2by refraction through the light input surface211. A majority of light beams (as those transmitted along paths indicated as (A) inFIGS. 3 and 4) is then totally reflected by the base sections213of the base surface212toward the microstructures34of the light output wall3. The majority of light beams is subsequently reflected by the microstructures34to propagate in the light output wall3, and is finally transmitted out from the light output surface33. When the majority of light beams is transmitted out from the diffusing structures331of the light output wall3, the majority of light beams can be projected uniformly on the required area. The base surface212further has a central portion disposed for allowing the light which is propagated from the light input surface211to refract through the base surface212and toward the lens space30. With such disposition, the rest of light beams entering into the base wall2by refraction through the light input surface211(as those transmitted along paths indicated as (B) inFIGS. 3 and 4) is transmitted into the lens space30, by refraction through the base surface212, and propagates forwardly. The light beams which propagate along the paths (A) and the paths (B) cooperately form a light pattern (seeFIG. 5) which satisfies the regulations, and which has a special visual effectiveness.

Referring toFIGS. 1, 4 and 5, the light pattern has a first area41projected by the light beams which propagate along the paths (A), and a second area42projected by the light beams which propagate along the path (B), and having a portion that corresponds to the light emitting member1in position, and that has brighter visual effectiveness.

Referring toFIGS. 1 and 4, it should be noted that, the first surface portion341of each of the microstructures34has a first virtual focus and a first focus length. The first virtual focuses of the first surface portions341of the microstructures34are located at the same point, and the first focus lengths of the first surface portions241are different. With such configurations, a better light transmitting efficiency can be assured and the light utilization rate is increased since the first surface portions341of the microstructures34can reflect the light beams toward the light output surface33with a certain angle of reflection so as to prevent the light beams from being transmitted out from the light output wall3by refraction through the outer surface32of the light output wall3.

An imaginary line (M) is defined to be perpendicular to the optical axis (L), and intersects with the optical axis (L) at a central point (C) which is located at a midpoint between vertical projection points of front and rear ends of the base surface212along the optical axis (L). Preferably, the first virtual focuses of the first surface portions341of the microstructures34are located on the optical axis (L), and are located between a front limit point which is 1 millimeter in front of the central point (C) (as indicated as virtual focus (F1) inFIG. 4), and a rear limit point which is 1 millimeter behind the central point (C) (as indicated as virtual focus (F2) inFIG. 4). With such configuration, the light transmitting efficiency is also improved.

When the first virtual focuses are located at different points, luminous intensities of different projected areas are also different. From the experiment, when the first virtual focuses are located at the central point (C), the maximum luminous intensity is 3920 candela, when the first virtual focuses are located between the front limit point and the rear limit point, the maximum luminous intensity is 3120 candela, and when the first virtual focuses are located at a position where is not between the front limit point and the rear limit point, the maximum luminous intensity is 1360 candela. It can be concluded that, when the first virtual focuses are located at the central point (C), the vehicle lamp lens has a better light transmitting efficiency.

With the disposition of the parabolic-shaped base sections213of the base surface212, the light beams can be accurately reflected toward the microstructures34. Each of the base sections213has a second virtual focus. The second virtual focuses are located at the same point (as indicated as virtual focus (F3) inFIG. 4), and are farer away from the light input surface211than the light emitting member1. With such configuration, a better light transmitting efficiency can be acquired.

It should be noted that, the light beams can be accurately reflected by the base sections213of the light input surface21and by the microstructures34since the configurations of the base sections213and the microstructures34need to cooperate with each other. When the second virtual focuses of the base sections213are located at the light emitting member1, or are located at a point which is closer to the light input surface211than the light emitting member1(i.e., in front of the light emitting member1), the light input surface211and the base surface212of the base wall2have to be disposed farer from the light emitting member1so as to obtain required optical effectiveness. In such manner, the thickness of the base wall2in the front-rear direction has to be increased, and such configuration doses not meet the disposition requirement. In contrast, the thickness of the base wall2of the vehicle lamp lens of the disclosure can be relatively thin.

From experiment data, the base wall2of the vehicle lamp lens of the disclosure can be controlled to be about 5.5 millimeters. However, when the second virtual focuses of the base sections213are located at the light emitting member1, the thickness of the base wall2has to be increased to 7 millimeters. When the second virtual focuses of the base sections213are located in front of the light emitting member1, the thickness of the base wall2has to be increased to 9.3 millimeters. In addition, the second virtual focuses of the base sections213are not preferably located on the optical axis (L). If the second virtual focuses of the base sections213are located on the optical axis (L), the light input surface211will have to be disposed at the same location as the light emitting member1, and such disposition is not applicable.

In conclusion, with the disposition of the parabolic-shaped base sections213and the parabolic-shaped first surface portions341of the microstructures34, the light beams can be efficiently transmitted in the vehicle lamp lens.