Projection optical system

Abstract

To provide a new projection optical system capable of forming a plurality of desired light distribution patterns by using a plurality of lenses.SOLUTION: This projection optical system comprises: a first lens for projecting first light emitted from a first light source to a first region below a horizontal line ahead of a vehicle; and a second lens for projecting second light emitted from a second light source to a second region upwardly adjacent to the first region. The second lens is disposed above the first lens such that a gap G is formed with respect to the first lens.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a projection optical system used in a vehicle lamp. [Background technology]

[0002] Conventionally, a vehicle lamp has been devised that includes a first light source that emits light that forms a low-beam light distribution pattern, a second light source that is positioned below the first light source and emits light that forms a high-beam light distribution pattern together with the light emitted from the first light source, a board on which the first and second light sources are mounted, a reflector unit that is positioned forward of the board, and a projection lens that is positioned forward of the reflector unit (see Patent Document 1). This vehicle lamp is configured to form a low-beam light distribution pattern and a high-beam light distribution pattern forward with a single projection lens using light emitted from the two light sources. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 068153 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in order to devise a vehicle headlamp that can form a light distribution pattern different from the low beam light distribution pattern and the high beam light distribution pattern, a third light source may be required to emit light that forms the different light distribution pattern. In such a case, if an attempt is made to form yet another light distribution pattern using the light emitted from the third light source with the projection lens described above, the projection lens may become larger and there may be many restrictions on the design of the optical control surface.

[0005] The present invention has been made in view of the above circumstances, and one of its exemplary purposes is to provide a new projection optical system that can form a plurality of desired light distribution patterns using a plurality of lenses. [Means for solving the problem]

[0006] To solve the above problems, one aspect of the present invention provides a projection optical system that includes a first lens that projects first light emitted from a first light source onto a first area below the horizon in front of a vehicle, and a second lens that projects second light emitted from a second light source onto a second area adjacent to and above the first area. The second lens is disposed above the first lens with a gap between them.

[0007] According to this aspect, the optical design of the first lens according to the first light emitted from the first light source and the optical design of the second lens according to the second light emitted from the second light source can be performed independently, thereby making it possible to form a plurality of desired light distribution patterns using a plurality of lenses.

[0008] The gap may be formed in a longitudinal region where the upper surface of the first lens and the lower surface of the second lens face each other, allowing the two lenses to be arranged one above the other with a gap therebetween.

[0009] When the first lens and the second lens are viewed from a side intersecting the vehicle longitudinal direction, the upper surface of the first lens may be an inclined surface that slopes downward toward the front of the vehicle, and the lower surface of the second lens may be an inclined surface that slopes downward toward the front of the vehicle. This makes it difficult to see the gap between the first lens and the second lens when the first lens and the second lens are viewed from the front of the vehicle.

[0010] When the first lens and the second lens are viewed from a side intersecting the vehicle longitudinal direction, the angle formed between the upper surface of the first lens and the lower surface of the second lens may be 5° or less.

[0011] The vertical width of the gap visible in a front view from the front of the vehicle may be 3 mm or less, making the gap between the first lens and the second lens less visible when the first lens and the second lens are viewed from the front of the vehicle.

[0012] The first lens may project third light emitted from a third light source having a plurality of light-emitting elements arranged in an array onto a third area above the horizon in front of the vehicle.

[0013] Any combination of the above components, and conversion of the present invention between a manufacturing method, a lighting fixture or lighting device, a light emitting module, a light source, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0014] According to the present invention, a plurality of desired light distribution patterns can be formed using a plurality of lenses. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view of a vehicle lamp according to an embodiment of the present invention; [Figure 2] FIG. 2 is an exploded perspective view of the vehicle lamp shown in FIG. [Figure 3] FIG. 2 is a front view of the vehicle lamp shown in FIG. [Figure 4] 4 is a cross-sectional view of the vehicle lamp shown in FIG. 3 along the line AA. [Figure 5] FIG. 2 is a schematic diagram for explaining the optical paths of light emitted from each light source. [Figure 6] Figure 6(a) is a schematic diagram showing a second area formed by illuminating the area in front of the vehicle with second light emitted from a second light source, Figure 6(b) is a schematic diagram showing a first area formed by illuminating the area in front of the vehicle with first light emitted from a first light source, and Figure 6(c) is a schematic diagram showing a third illumination area formed by illuminating the area in front of the vehicle with third light emitted from a third light source. [Figure 7] Figure 7(a) shows a low beam light distribution pattern PL that mainly illuminates an area below the horizon on a screen in front of the vehicle, and Figure 7(b) shows a high beam light distribution pattern PH that mainly illuminates an area above the horizon on a screen in front of the vehicle. [Figure 8] FIG. 2 is a front view of the reflector as seen from the front of the vehicle. [Figure 9] 9(a) is a cross-sectional view taken along line BB including components in the vicinity of the reflector shown in FIG. 8, and FIG. 9(b) is an enlarged cross-sectional view of region C in FIG. 9(a). [Figure 10] FIG. 10(a) is a side view of a projection optical system according to another example of the present embodiment, and FIG. 10(b) is a front view of the projection optical system shown in FIG. 10(a) as seen from direction C. [Figure 11] FIG. 11(a) is a side view of the projection optical system according to this embodiment, and FIG. 11(b) is a front view of the projection optical system shown in FIG. 11(a) as seen from direction D. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0017] Fig. 1 is a perspective view of a vehicle lamp according to this embodiment. Fig. 2 is an exploded perspective view of the vehicle lamp shown in Fig. 1. Fig. 3 is a front view of the vehicle lamp shown in Fig. 1. Fig. 4 is a cross-sectional view taken along line AA of the vehicle lamp shown in Fig. 3. The vehicle lamps shown in Figs. 1 to 4 are vehicle headlamps, and are configured to be able to form both low beam and high beam light distribution patterns.

[0018] The vehicle lamp 10 includes a projection lens 12, a lens holder 14, a reflector 16, a circuit board 18, and a heat sink 20. The projection lens 12 is composed of two components: a first projection lens 12a located below and a second projection lens 12b located above, and controls the optical path of light emitted from each light source. Each lens is attached to a predetermined position in the lens holder 14. Each lens is manufactured by injection molding using a highly transparent and heat-resistant resin material such as acrylic or polycarbonate. The lens holder 14 is fastened to the heat sink 20 with screws 22.

[0019] The reflector 16 is made of a metal or resin material and has a horizontally elongated base surface portion 16a facing the front-to-rear direction, openings 16b and 16c formed in the center of the reflector 16, side reflection portions 16d provided so as to protrude forward from both the left and right sides of the opening 16b, and an upper reflector 16e whose inner surface of a beam-shaped portion above the opening 16b serves as a reflection surface.

[0020] A shade 24, which is a plate-shaped member, is attached to the lower surface of the side reflecting portion 16d and protrudes forward from the lower edge of the opening 16b. The shade 24 is held by the reflector 16 so that its plate surface is aligned with the horizontal direction of the vehicle. A shade 26, which is a plate-shaped member, is attached to the base surface portion 16a. The shade 26 is a plate-shaped member and is held by the reflector 16 so that its plate surface is aligned with the vertical direction of the vehicle. The vehicle lamp 10 according to this embodiment further includes a shade 28. The shade 28 is a plate-shaped member that blocks light that passes through the opening 16b and travels diagonally upward, and also blocks light that passes through the opening 16c and travels diagonally downward. In this embodiment, the shade 26 and the shade 28 are a single member arranged in an L-shape, but the shade 26 and the shade 28 may be separate members.

[0021] The circuit board 18 has a first light source 30a having a plurality of light-emitting elements 28a arranged in a horizontal row for forming a first region of a low-beam light distribution pattern, a second light source 30b having a plurality of light-emitting elements 28b arranged in a horizontal row for forming a second region of a low-beam light distribution pattern, a third light source 30c having a plurality of light-emitting elements 28c arranged in a horizontal row for forming a high-beam light distribution pattern, and a drive circuit (not shown) that drives each light-emitting element.

[0022] The third light source 30c is disposed adjacent to the first light source 30a. The first light source 30a is located on the upper stage, and the third light source 30c is located on the lower stage. The drive circuit is a combination of passive elements such as capacitors and coils, active elements such as transistors and diodes, IC chips, memory, etc., and functions as a control unit that controls the on / off of the first light source 30a, the second light source 30b, and the third light source 30c. The circuit board 18 is a mounting unit on which each light source is mounted, and is fixed at a predetermined position on the heat sink 20. In other words, the circuit board 18 and the heat sink 20 are also an integrated mounting unit.

[0023] A lens plate 32 is disposed in front of the first light source 30a and the third light source 30c, and the lens plate 32 collects and blocks part of the light emitted from the first light source 30a and the third light source 30c. In addition, a lens plate 34 is disposed in front of the second light source 30b, and the lens plate 32 collects the light emitted from the second light source 30b. The lens plate 32 and the lens plate 34 are sandwiched between the reflector 16 and the circuit board 18. In this state, the reflector 16 is fastened to the heat sink 20 with screws 36, thereby determining the positional relationship of each component.

[0024] FIG. 5 is a schematic diagram for explaining the optical paths of light emitted from each light source. Note that some components of the vehicle lamp 10 have been omitted or modified to the extent that it does not affect the explanation. The first light L1 emitted from the first light source 30a is partially blocked by the shade 24. The first projection lens 12a projects the blocked first light L1 onto a first region below the horizon. The second light L2 emitted from the second light source 30b is partially blocked by the shade 26. The second projection lens 12b projects the blocked second light L2 onto a second region below the horizon.

[0025] Fig. 6(a) is a schematic diagram showing a second region formed by illuminating the area in front of the vehicle with second light emitted from a second light source, Fig. 6(b) is a schematic diagram showing a first region formed by illuminating the area in front of the vehicle with first light emitted from a first light source, and Fig. 6(c) is a schematic diagram showing a third illumination region formed by illuminating the area in front of the vehicle with third light emitted from a third light source. Fig. 7(a) is a diagram showing a low-beam light distribution pattern PL that mainly illuminates an area below the horizon on a screen in front of the vehicle, and Fig. 7(b) is a diagram showing a high-beam light distribution pattern PH that mainly illuminates an area above the horizon on a screen in front of the vehicle.

[0026] The first region R1 shown in Fig. 6(b) has a first cutoff line C1. The second region R2 shown in Fig. 6(a) is adjacent to and above the first region R1 and has a second cutoff line C2. The control unit according to this embodiment turns on the first light source 30a and the second light source 30b to form a low-beam light distribution pattern including the first region R1 and the second region R2, as shown in Fig. 7(a).

[0027] In the vehicle lamp 10 according to this embodiment, the first light source 30a and the second light source 30b are mounted on the same circuit board 18 (heat sink 20), and therefore, variations in the positions of the first region R1 and the second region R2 can be reduced, as in the low beam light distribution pattern PL shown in FIG. 7(a).

[0028] In addition, in the vehicle lamp 10, the first cutoff line C1 in the first region R1 formed by the shade 24 and the second cutoff line C2 in the second region R2 formed by the shade 26 have different shapes. This makes it possible to realize a plurality of light distribution patterns having different cutoff lines by controlling the on / off states of the first light source 30a and the second light source 30b.

[0029] Furthermore, the reflector 16 according to this embodiment holds both the shade 24 and the shade 26. This makes it possible to reduce variations in the positions of the first cutoff line C1 and the second cutoff line C2. Furthermore, the reflector 16 may be a resin reflector that reflects a portion of the first light L1. For example, a metal film is formed on the reflective surface of the reflector 16. This allows a portion of the first light L1 to be used for the light distribution pattern.

[0030] As described above, the vehicular lamp 10 according to this embodiment further includes the third light source 30c, which is an array of light-emitting elements 28c. The third light source 30c is mounted on the circuit board 18 so as to be located below the first light source 30a in a front view of the circuit board 18 seen from the front of the vehicle. As shown in FIG. 5, the shade 24 blocks a portion of the third light L3 emitted from the third light source 30c. The first projection lens 12a projects the blocked third light L3 onto a third region (FIG. 6(c)) above the horizon.

[0031] The control unit according to the present embodiment forms a high beam light distribution pattern PH including the first region R1 and the third region R3 by turning on the first light source 30a and the third light source 30c, thereby forming a high beam light distribution pattern PH including an area above the low beam light distribution pattern PL.

[0032] Furthermore, the control unit can form a variable light distribution pattern PH' that includes first region R1 and part of third region R3 by turning on first light source 30a, turning on only some of multiple light-emitting elements 28c of third light source 30c, and turning off or dimming second light source 30b. This makes it possible to suppress brightness near second cutoff line C2 when variable light distribution pattern PH' is formed.

[0033] In this way, in the vehicle lamp 10 according to this embodiment, the light sources that illuminate the first region R1, the second region R2, and the third region R3 are mounted on the same circuit board 18, and in addition, the shades are also held by the same reflector 16, so that variation in the position of the cutoff lines of multiple light distribution patterns can be reduced.

[0034] Fig. 8 is a front view of the reflector as seen from the front of the vehicle, Fig. 9(a) is a cross-sectional view taken along line BB including components near the reflector shown in Fig. 8, and Fig. 9(b) is an enlarged cross-sectional view of area C in Fig. 9(a).

[0035] 8 is formed by melting and fixing a pin 16g provided on the base surface portion 16a of the reflector 16 while the pin 16g is inserted into a positioning hole in the shade 26. Also, the thermal caulking portion 40 is formed by melting and fixing a pin (not shown) provided on the underside of the side reflection portion 16d of the reflector 16 while the pin is inserted into a positioning hole in the shade 24. This allows the shade 24 and the shade 26 to be fixed to the reflector 16 without using screws, thereby making it possible to reduce the size of each shade.

[0036] Furthermore, the lens plate 32 and the lens plate 34 according to the present embodiment are fixed in a state in which they are pressed against the circuit board 18 on the back surface of the reflector 16. In this case, it is preferable that the pressed portion 34a of the lens plate 34 is positioned away from the direct back of the pin 16g when viewed from the front of the reflector 16. If the reflector 16 is a resin molded product, a depression due to sink may occur on the back surface of the pin 16g, and if this depression and the pressed portion 34a are positioned to overlap, the pressing force with which the reflector 16 presses the lens plate 34 against the circuit board 18 will be weakened.

[0037] (Projection optical system) The projection optical system in the above-described vehicle lamp 10 will now be further described. The projection optical system (projection lens 12) according to this embodiment includes a first projection lens 12a that projects a first light L1 emitted from a first light source 30a onto a first region below the horizon ahead of the vehicle, and a second projection lens 12b that projects a second light L2 emitted from a second light source 30b onto a second region adjacent to and above the first region. The second projection lens 12b is disposed above the first projection lens 12a with a gap therebetween (see FIGS. 4 and 5).

[0038] This allows the optical design of the first projection lens 12a according to the first light L1 emitted from the first light source 30a and the optical design of the second projection lens 12b according to the second light L2 emitted from the second light source 30b to be performed independently. As a result, the vehicle lamp 10 according to this embodiment can form at least three light distribution patterns (a low-beam light distribution pattern PL, a high-beam light distribution pattern PH, and a variable light distribution pattern PH') using two lenses.

[0039] Fig. 10(a) is a side view of a projection optical system according to another example of this embodiment, and Fig. 10(b) is a front view of the projection optical system shown in Fig. 10(a) as viewed from direction C. As shown in Figs. 10(a) and 10(b), a gap G between the lenses of the projection optical system 42 is formed in the longitudinal region where the upper surface 43a of the first projection lens 42a and the lower surface 43b of the second projection lens 42b face each other. This allows the two lenses to be arranged one above the other with the gap G between them.

[0040] On the other hand, when the projection optical system 42 is viewed from the front of the vehicle, the circuit board 18 and the light sources on the rear side of the projection optical system 42 may be visible due to the gap G. One reason for this is that the upper surface 43a of the first projection lens 42a is an inclined surface that slopes downward toward the front of the vehicle, and the lower surface 43b of the second projection lens 42b is an inclined surface that slopes upward toward the front of the vehicle.

[0041] Therefore, by devising the tilt directions of the upper surface 43a of the first projection lens 42a and the lower surface 43b of the second projection lens 42b, it is possible to make it difficult to see the components on the back side of the projection optical system 42, thereby improving the design of the projection optical system including the lenses. Fig. 11(a) is a side view of the projection optical system according to this embodiment, and Fig. 11(b) is a front view of the projection optical system shown in Fig. 11(a) as seen from direction D.

[0042] As shown in FIG. 11(a), when the first projection lens 12a and the second projection lens 12b are viewed from the side intersecting the longitudinal direction of the vehicle, the upper surface 13a of the first projection lens 12a is an inclined surface that slopes downward toward the front of the vehicle, and the lower surface 13b of the lens of the second projection lens 12b is an inclined surface that slopes downward toward the front of the vehicle. As a result, when the first projection lens 12a and the second projection lens 12b are viewed from the front of the vehicle (direction of arrow D), the gap G between the first projection lens 12a and the second projection lens 12b is difficult to see. As a result, components on the back of the projection optical system are also difficult to see, improving the design of the projection optical system including the lenses. Note that both the upper surface 13a and the lower surface 13b may be inclined surfaces that slope upward toward the front of the vehicle.

[0043] 11(a), when the first projection lens 12a and the second projection lens 12b are viewed from the side intersecting the longitudinal direction of the vehicle, the angle α formed by the upper surface 13a of the first projection lens 12a and the lower surface 13b of the second projection lens 12b is preferably 5° or less. Note that the upper surface 13a and the lower surface 13b in FIG. 11(a) are substantially parallel (α≒0°).

[0044] Furthermore, it is preferable that the vertical width W (shortest distance between the upper and lower surfaces) of the gap G visible in a front view from the front of the vehicle of the projection lens 12 is 3 mm or less. This makes it more difficult to see the gap G between the first projection lens 12a and the second projection lens 12b when viewing the first projection lens 12a and the second projection lens 12b from the front of the vehicle.

[0045] (Variation) In the vehicle lamp 10 described above, both the shade 24 and the shade 26 are attached to the reflector 16, but the shade 26 may be disposed in front of the second light source 30b via another component.

[0046] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations and substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to make modifications to the embodiments such as various design changes, and such modified embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0047] 10 Vehicle lamp, 12 Projection lens, 12a First projection lens, 12b Second projection lens, 13a Upper surface, 13b Lower surface, 14 Lens holder, 16 Reflector, 16a Base surface portion, 16b Opening, 16c Opening, 16d Side reflection portion, 16e Upper reflector, 16g Pin, 18 Circuit board, 20 Heat sink, 24 Shade, 26 Shade, 28a Light-emitting element, 28b Light-emitting element, 28c Light-emitting element, 30a First light source, 30b Second light source, 30c Third light source, 32 Lens plate, 34 Lens plate, 34a Pressurized portion, 38 Thermal caulking portion, 40 Thermal caulking portion, C1 First cut-off line, C2 second cutoff line, L1 first light, L2 second light, L3 third light, R1 first region, R2 second region, R3 third region.

Claims

1. a first lens that projects first light emitted from a first light source onto a first region below the horizon in front of the vehicle; a second lens that projects second light emitted from a second light source onto a second area adjacent to and above the first area; A projection optical system, wherein the second lens is disposed above the first lens with a gap therebetween.

2. 2. The projection optical system according to claim 1, wherein the gap is formed in a longitudinal region where the upper surface of the first lens and the lower surface of the second lens face each other.

3. 3. The projection optical system according to claim 2, wherein, when the first lens and the second lens are viewed from a side intersecting the vehicle's fore-and-aft direction, the upper surface of the first lens is an inclined surface that slopes downward toward the front of the vehicle, and the lower surface of the second lens is an inclined surface that slopes downward toward the front of the vehicle.

4. 4. The projection optical system according to claim 3, wherein when the first lens and the second lens are viewed from a side intersecting the longitudinal direction of the vehicle, the angle formed between the upper surface of the first lens and the lower surface of the second lens is 5° or less.

5. 5. The projection optical system according to claim 1, wherein the gap has a vertical width of 3 mm or less when viewed from the front of the vehicle.

6. 5. The projection optical system according to claim 1, wherein the first lens projects third light emitted from a third light source having a plurality of light-emitting elements arranged in an array onto a third region above the horizon in front of the vehicle.

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