Vehicle lamp lens

A lamp lens is adapted to transmit light, and includes spaced-apart light input and output surfaces and a reflecting surface. The light input surface has a surrounding surface portion and an end surface portion connected to a front end of the surrounding surface portion. The reflecting surface extends from the light input surface to the light output surface, and has a plurality of reflecting segments and optical structures. The reflecting segments are adapted for total reflection of a portion of the light which enters the lamp lens through the light input surface. Each adjacent two of the reflecting segments forma stepped surface structure. The optical structures are adapted to prevent total reflection of a portion of the light.

FIELD

The disclosure relates to a lamp lens, and more particularly to a lamp lens for vehicles.

BACKGROUND

A conventional vehicle lamp generally includes a reflecting seat for reflecting light to project the same forwardly out of the conventional vehicle lamp. The reflecting seat has a reflecting surface generally formed through a vacuum coating process. However, choice of the material of the body of the reflecting seat is limited due to the high temperature condition required by the vacuum coating process. In addition, the bonding ability of a coating layer on the inner side of the body of the reflecting seat also restricts the choice of the material of the body of the lamp cover. Moreover, since the vacuum coating process often causes the reflecting surface to be uneven, the optical precision of the conventional vehicle lamp is affected, thereby resulting in an undesired projected light shape, and thereby also affecting the reflectability of light which leads to great light loss.

Accordingly, a vehicle lamp lens has previously been designed specifically to improve the abovementioned drawbacks. Light that enters such lamp lens will exit through a light output surface of the lamp lens after undergoing total internal reflection (TIR). According to a theoretical calculation, reflectivity of such lamp lens may reach 100%. In comparison with the vehicle lamp having the abovementioned vacuum-coated reflecting seat, a vehicle lamp equipped with the previously designed lamp lens relatively has a reduced light loss and an improved optical precision.

Taiwanese Patent No. 1491833 discloses a vehicle illumination apparatus including a light source and a collimator lens. The collimator lens guides light emitted from the light source through TIR. However, the output light from such collimator lens may result in undesired residual light on the illumination plane, which causes occurrence of glare and hence negatively affects passerby and drivers. For example, light emitted from a low-beam lamp may generate residual light at a zone above the cut-off line.

SUMMARY

Therefore, an object of the disclosure is to provide a lamp lens that can alleviate at least one of the drawbacks associated with the abovementioned prior art.

The lamp lens is adapted to transmit light that is emitted from a lighting member. The lamp lens includes a light input surface, a light output surface, and a reflecting surface. The light input surface is adapted to face the lighting member and has a surrounding surface portion and an end surface portion. The surrounding surface portion surrounds an optical axis extending in a front-rear direction. The end surface portion is connected to a front end of the surrounding surface portion and is disposed on the optical axis. The light output surface is spaced apart from the light input surface along the optical axis. The reflecting surface extends from the light input surface to the light output surface, surrounds the optical axis, and has a plurality of reflecting segments and a plurality of optical structures. The reflecting segments are adapted for total reflection of a portion of the light which enters the lamp lens through the light input surface. Each adjacent two of the reflecting segments form a stepped surface structure. The optical structures are adapted to prevent total reflection of a portion of the light.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 4, an embodiment of a lamp lens according to the disclosure is adapted to transmit light that is emitted from a lighting member9(seeFIG. 4), which may be a light-emitting diode (LED). The lamp lens may be made of a light-transmissive resin material. The lamp lens includes a light input surface1, a light output surface2, and a reflecting surface3.

The light input surface1is adapted to face the lighting member9. The light input surface1has a surrounding surface portion11surrounding an optical axis (L) that extends in a front-rear direction, and an end surface portion12connected to a front end of the surrounding surface portion11and disposed on the optical axis (L).

The light output surface2is disposed in front of and spaced apart from the light input surface1along the optical axis (L). The light output surface2has a ring surface portion21surrounding the optical axis (L), and a central surface portion22disposed on the optical axis (L) and surrounded by the ring surface portion21. The ring surface portion21is planar and smooth without any pattern formed thereon. The ring surface21is adapted for passage of a portion of the light which enters the lamp lens through the surrounding surface portion11of the light input surface1. The central surface portion22is a curved surface, and is designed to possess multiple parts that have different curvatures. Specifically, the central surface portion22has an upper segment recessed from the ring surface portion21, and a lower segment protruding from the ring surface portion21. The central surface portion22is adapted for passage of a portion of the light which enters the lamp lens through the end surface portion12of the light input surface1.

The reflecting surface3extends from the light input surface1to the ring surface portion21of the light output surface2(i.e., a front end of the reflecting surface3is connected to the ring surface portion21of the light output surface2), and surrounds the optical axis (L). The reflecting surface3has two first reflecting portions31spaced apart from each other in a left-right direction that is perpendicular to the front-rear direction, a second reflecting portion32connected between bottom edges of the first reflecting portions31, and a third reflecting portion33connected between top edges of the first reflecting portions31.

Each of the first reflecting portions31has a plurality of reflecting segments311adapted for total reflection of a portion of the light which enters the lamp lens through the light input surface1. Each adjacent two of the reflecting segments311form a stepped surface structure. The second reflecting portion32has two first sections321spaced apart from each other in the left-right direction, a second section322disposed between and lower than the first sections321, and two third sections323. Each of the third sections323interconnects an inner end of a respective one of the first sections321and the second section322. The second reflecting portion32of the reflecting surface3is formed with a plurality of optical structures34that are adapted to prevent total reflection of a portion of the light.

Referring toFIG. 4, the optical structures34are arranged in the front-rear direction. Each of the optical structures34has a main surface341adapted for passage of a portion of the light therethrough, and a connecting surface342connected to the main surface341and cooperating with the main surface341to define a groove35that extends substantially in the left-right direction. The main and connecting surfaces341,342of the optical structures34are alternately arranged in the front-rear direction. For each of the optical structures34, an imaginary plane extending along the main surface341and the optical axis (L) cooperatively define an acute angle (θ) larger than 18 degrees for improving prevention of the total reflection of the portion of the light passing through the main surface341. If the acute angle (θ) is less than or equal to 18 degrees, the portion of the light passing through the main surface341is more likely to generate glare above the cut-off line.

Referring toFIGS. 1, 4 and 5, in use, a part of the light (as indicated by arrows (A1, A2, B) inFIGS. 4 and 5) emitted from the lighting member9enters the lamp lens through the surrounding surface portion11of the light input surface1. The other part of the light (as indicated by arrows (C) inFIGS. 4 and 5) emitted from the lighting member9enters the lamp lens through the end surface portion12of the light input surface1. Since the end surface portion12curves rearwardly away from the light output surface2, the other part of the light would concentrate after passing through the end surface portion12, travel toward the light output surface2in a direction that is substantially parallel to the optical axis (L), and finally exit through the central surface portion22.

On the other hand, the part of the light which enters the lamp lens through the surrounding surface portion11is divided into a first part of the light (as indicated by arrows (A1) inFIG. 5) reflected by the first reflecting portions31of the reflecting surface3, a second part of the light (as indicated by arrow (A2) inFIG. 4) reflected by the third reflecting portion33of the reflecting surface3, and a third part of the light (as indicated by arrows (B) inFIG. 4) passing through the second reflecting portion32of the reflecting surface3. After being reflected (mostly through TIR), the first and second parts of the light (as indicated by arrows (A1, A2)) exit through the ring surface portion21of the light output surface2to result in a uniform light output. All of the parts of the light can cooperatively form a light shape in conformity with local laws on a projection plane that is in front of the lamp lens, and can form a cut-off line at a proper position.

Furthermore, since the configuration of the optical structures34is designed to prevent total reflection, the third part of the light (as indicated by arrows (B)) can be refracted to exit the lamp lens through the main surfaces341of the optical structures34. It should be noted that, without the optical structures34, the third part of the light might be reflected toward the light output surface2and cause residual light around the cut-off line which generates undesired glare.

It should be noted that, the optical structures34are formed by a numerical control machine in this embodiment, but are not limited to such formation process in other embodiments. The optical structures34may be configured as textured structures that are adapted for facilitating diffuse reflection of the light emitted thereto from the lighting member9. Such textured structures may also prevent total reflection of the light and reduce residual light. To make the textured structures, the second reflecting portion32of the reflecting surface3is made rough by a wet-etching process. In addition, the location of the optical structures34is not limited to the second reflecting portion32, namely, the optical structures34may be disposed on a desired portion of the reflecting surface3in other embodiments.

It is worth mentioning that since the reflecting segments311of the first reflecting portions31have different curvatures to optimally reflect the first part of the light with different incident angles, the first part of the light can be reflected at different proper reflecting angles and paths for projecting light shapes that are uniformly diffused. In addition, the first and second parts of the light can be projected below the cut-off line for preventing the zone above the cut-off line from being too bright to comply with the local laws. Moreover, with a proper design of the curvatures of the reflecting segments311, a width of the output light in the left-right direction can be increased.

Furthermore, by changing the curvature of the central surface portion22of the light output surface2during the manufacturing process of the lamp lens, the width of the output light in the lift-right direction can also be increased, and the position of the cut-off line can be adjusted. It has been found via experiment that if the central surface portion22is a planar surface, residual light might occur around the cut-off line, which might also be against the local laws. By virtue of the different curvatures of the reflecting segments311and the curved central surface portion22, the saturation, uniformity and light shape of the output light, and the position of the cut-off line can be controlled, thereby increasing optical precision. It should be noted that, while the ring surface portion21and the central surface portion22of the light output surface2are exemplified to have different curvatures, they may be arranged not to be at the same plane in other embodiments (for example, the central surface portion22may be in a rear side of the ring surface portion21) to form two different regions of the light output surface2.

In summary, due to the optical structures34, total reflection of the portion of the light passing therethrough may be prevented, so as to reduce residual light and glare. As a result, the lamp lens according to the present disclosure can improve driving safety.