Headlamp device

Abstract

The LED element (10) has a single light-emitting surface. The light-emitting surface has a first portion (151) and a second portion (152) arranged in the first direction. The reflector (35) has a reflecting surface (351) having a paraboloid-based shape, and light emitted from the light emitting surface is reflected by the reflecting surface (351) to form a low-beam light distribution pattern in front of the moving body. The light intensity per unit area of the light (L1) emitted from the first portion (151) is higher than the light intensity per unit area of the light (L2) emitted from the second portion (152). The first portion (151) is positioned closer to one end edge (150a) than the center of the light-emitting surface in the first direction. One end edge (150a) corresponds to the upper end edge of the low-beam light distribution pattern.

Description

Technical Field

[0001] The present invention relates to a headlamp device mounted on a moving body. Background Art

[0002] Patent Document 1 discloses a headlamp device mounted on a vehicle as an example of a moving body. The headlamp device includes a semiconductor light-emitting element and a reflector. The reflector has a reflecting surface with a shape based on a paraboloid, and uses this reflecting surface to reflect the light emitted from the semiconductor light-emitting element to form a low-beam light distribution pattern in front of the vehicle. One end edge of the light-emitting surface of the semiconductor light-emitting element corresponds to the upper end edge (so-called cut-off line between light and darkness) of the low-beam light distribution pattern.

[0003] Patent Document 1 also discloses a headlamp device including a projection lens, a semiconductor light-emitting element, a reflector, and a light-shielding cover. The reflector has a reflecting surface with a shape based on an ellipsoid of revolution, reflects the light emitted from the semiconductor light-emitting element on this reflecting surface and passes it through the projection lens, thereby forming a low-beam light distribution pattern in front of the vehicle. The light-shielding cover defines the shape of the upper end edge (so-called cut-off line between light and darkness) of the low-beam light distribution pattern by blocking a part of the light reflected by the reflector.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-238511 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] There is a demand to improve the far-away visibility of the low-beam light distribution pattern formed by the headlamp device.

[0009] Technical Means for Solving the Problem

[0010] An example of one aspect provided by the present invention is a headlamp device mounted on a moving body, the headlamp device including:

[0011] a semiconductor light-emitting element having a single-piece light-emitting surface; and

[0012] a reflector having a reflecting surface with a shape based on a paraboloid, using this reflecting surface to reflect the light emitted from the light-emitting surface to form a low-beam light distribution pattern in front of the moving body,

[0013] the light-emitting surface having a first part and a second part arranged along a first direction,

[0014] The light intensity per unit area of the light emitted from the first part is higher than the light intensity per unit area of the light emitted from the second part.

[0015] The first part is located at a position closer to one end edge of the light emitting surface in the first direction than the center of the light emitting surface in the first direction.

[0016] The one end edge corresponds to the upper end edge of the low beam light distribution pattern.

[0017] An example of an aspect provided by the present invention is a headlight device mounted on a moving body, the headlight device having:

[0018] A projection lens;

[0019] A semiconductor light emitting element having a single light emitting surface;

[0020] A reflector having a reflecting surface with an ellipsoidal surface as a basis, and using the reflecting surface to reflect the light emitted from the light emitting surface and pass through the projection lens, thereby forming at least a part of a low beam light distribution pattern in front of the moving body; and

[0021] A light shield that defines the shape of the upper end edge of the low beam light distribution pattern by blocking a part of the light reflected by the reflector.

[0022] The light emitting surface has a first part and a second part arranged in a first direction.

[0023] The light intensity per unit area of the light emitted from the first part is higher than the light intensity per unit area of the light emitted from the second part.

[0024] The first part is located at a position closer to one end edge of the light emitting surface in the first direction than the center of the light emitting surface in the first direction.

[0025] A part of the light emitted from the first part is blocked by the light shield.

[0026] Advantages of the Invention

[0027] According to the structures of the above-described aspect examples, it is possible to form a light distribution pattern in front of the moving body in which the luminous intensity locally increases near the upper end edge of the low beam light distribution pattern while maintaining the amount of the light beam. Thus, the distant visibility of the low beam light distribution pattern formed by the headlight device can be improved. In order to obtain such a light distribution pattern, it is not necessary to particularly change the structure of the reflector, nor is it necessary to use a plurality of LED elements having different luminous brightnesses. Therefore, it is also possible to suppress the enlargement and complication of the optical system of the headlight device. Brief Description of the Drawings

[0028] Figure 1 Illustrates the appearance of an LED element of an embodiment.

[0029] Figure 2 Illustrates along Figure 1 The cross-sectional structure viewed from the arrow direction along line II-II.

[0030] Figure 3 Illustrates a vehicle equipped with the above LED element.

[0031] Figure 4 Illustrates the appearance of a headlight device of an embodiment.

[0032] Figure 5 Illustrates along Figure 4 The cross-sectional structure viewed from the arrow direction along line IV-IV.

[0033] Figure 6 Shows the low beam pattern formed by the headlight device of the comparative example.

[0034] Figure 7 Illustrates Figure 4 The appearance of the reflector.

[0035] Figure 8 Illustrates Figure 4 The operation of the headlight device.

[0036] Figure 9 Illustrates by Figure 4 The low beam pattern formed by the headlight device.

[0037] Figure 10 Illustrates the structure of the headlight device of other embodiments.

[0038] Figure 11 Shows the low beam pattern formed by the headlight device of the comparative example.

[0039] Figure 12 Illustrates Figure 10 The operation of the headlight device.

[0040] Figure 13 Illustrates by Figure 10 The low beam pattern formed by the headlight device. Detailed Description of the Embodiment

[0041] Hereinafter, examples of embodiments will be described in detail with reference to the accompanying drawings. In each of the drawings used in the following description, the scale is changed as necessary so that each element can be recognized in size.

[0042] Figure 1Illustrates the appearance of a light-emitting diode element (hereinafter simply referred to as an LED element) 10 of an embodiment. The LED element 10 is an example of a semiconductor light-emitting element. Figure 2 Illustrates a cross-sectional structure viewed from the arrow direction along the line II-II in Figure 1 .

[0043] The LED element 10 includes an opto-semiconductor laminate 11. The opto-semiconductor laminate 11 includes a p-type semiconductor layer 111, an n-type semiconductor layer 112, and a light-emitting layer 113. The p-type semiconductor layer 111, the n-type semiconductor layer 112, and the light-emitting layer 113 are arranged in the up-down direction in Figure 2 . In the following description, the up-down direction in Figure 2 is referred to as the "lamination direction".

[0044] The p-type semiconductor layer 111 is formed of p-type gallium nitride doped with magnesium. The p-type is an example of a first conductivity type.

[0045] The n-type semiconductor layer 112 is formed of n-type gallium nitride doped with silicon. The n-type is an example of a second conductivity type. The second conductivity type is a conductivity type opposite to the first conductivity type.

[0046] The light-emitting layer 113 is located between the p-type semiconductor layer 111 and the n-type semiconductor layer 112. The light-emitting layer 113 has a multi-quantum well structure including a well layer formed of indium gallium nitride and a barrier layer formed of gallium nitride. The light-emitting layer 113 is configured to emit light by the current supply described later.

[0047] The LED element 10 includes an insulating portion 12. The insulating portion 12 has electrical insulation. The insulating portion 12 extends in the lamination direction and divides the opto-semiconductor laminate 11 into electrically insulated first region R1 and second region R2. That is, the first region R1 and the second region R2 respectively include the p-type semiconductor layer 111, the n-type semiconductor layer 112, and the light-emitting layer 113 arranged in the lamination direction.

[0048] The first region R1 and the second region R2 are arranged in the left-right direction in Figure 2 . In the following description, the left-right direction in Figure 2 is referred to as the "arrangement direction". The arrangement direction intersects the lamination direction. The arrangement direction is an example of a first direction. The lamination direction is an example of a second direction.

[0049] In Figure 1 and Figure 2 , the width dimension of the insulating portion 12 in the arrangement direction as observed from the lamination direction is enlarged for better visual recognition. In this example, the insulating portion 12 is formed of a silicon oxide such as silicon dioxide. As long as electrical insulation can be ensured, an appropriate method such as the formation of a gap can be adopted.

[0050] The LED element 10 includes a light-transmitting layer 13. The light-transmitting layer 13 extends across a first region R1 and a second region R2. The light-transmitting layer 13 is configured to allow the light emitted from the light-emitting layer 113 to pass through. The light-transmitting layer 13 is formed of a material having electrical insulation properties. The light-transmitting layer 13 has a monolithic structure.

[0051] The term "monolithic structure" in this specification refers to a one-piece structure without physical discontinuity, which is used to distinguish from the meaning of a structure integrated by combining multiple components using various methods. As examples of various methods, bonding, joining, fusing, welding, engaging, fitting, screwing, etc. can be cited.

[0052] The LED element 10 includes a first conductive portion 141. The first conductive portion 141 is formed of a conductive material. The first conductive portion 141 is electrically connected to the n-type semiconductor layer 112 in the first region R1.

[0053] The LED element 10 includes a second conductive portion 142. The second conductive portion 142 is formed of a conductive material. The second conductive portion 142 electrically connects the p-type semiconductor layer 111 in the first region R1 and the n-type semiconductor layer 112 in the second region R2.

[0054] The LED element 10 includes a third conductive portion 143. The third conductive portion 143 is formed of a conductive material. The third conductive portion 143 is electrically connected to the p-type semiconductor layer 111 in the second region R2.

[0055] Therefore, when current is supplied to the first conductive portion 141, the current reaches the second conductive portion 142 via the n-type semiconductor layer 112 and the p-type semiconductor layer 111 in the first region R1, causing the light-emitting layer 113 in the first region R1 to emit light L1. Further, the current reaches the third conductive portion 143 from the second conductive portion 142 via the n-type semiconductor layer 112 and the p-type semiconductor layer 111 in the second region R2, causing the light-emitting layer 113 in the second region R2 to emit light L2.

[0056] That is, the first region R1 and the second region R2 of the opto-semiconductor laminate 11 having the light-transmitting layer 13 with a monolithic structure act as two independent light sources that emit light with different light-emitting intensities.

[0057] The LED element 10 includes a wavelength conversion layer 15. The wavelength conversion layer 15 has a monolithic structure that extends across the first region R1 and the second region R2. The wavelength conversion layer 15 is disposed so as to cover the light-transmitting layer 13. In other words, the light-transmitting layer 13 is located between the opto-semiconductor laminate 11 and the wavelength conversion layer 15. Therefore, the light L1 and the light L2 that have passed through the light-transmitting layer 13 pass through the wavelength conversion layer 15.

[0058] The upper surface of the wavelength conversion layer 15 forms the light emitting surface 150 of the LED element 10. In other words, the LED element 10 has a single light emitting surface 150. The light emitting surface 150 includes a first portion 151 and a second portion 152. The first portion 151 is arranged to face the first region R1 in the stacking direction. The second portion 152 is arranged to face the second region R2 in the stacking direction.

[0059] The wavelength conversion layer 15 contains a phosphor to perform a desired wavelength conversion function on the passing light. In this example, the phosphor is selected such that the light passing through the wavelength conversion layer 15 is white. As an example of the phosphor, Y3Al5O 12 、Gd3Al5O 12 、Ba2SiO4, Sr2SiO4, La3Si6N 11 、Y3Si6N 11 、cerium, europium, etc. The wavelength conversion layer 15 can be realized by a ceramic phosphor, a phosphor-containing glass substrate using a low melting point glass, a phosphor-containing resin layer using a silicone resin / epoxy resin, etc.

[0060] The light L1 and the light L2 emitted from the opto-semiconductor laminate 11 are blue. When the blue light L1 is incident on the wavelength conversion layer 15, the phosphor emits yellow light. As a result, white light L1 is emitted from the first portion 151. Similarly, when the blue light L2 is incident on the wavelength conversion layer 15, the phosphor emits yellow light. As a result, white light L2 is emitted from the second portion 152.

[0061] The LED element 10 includes a substrate 16. The substrate 16 supports the first conductive portion 141, the second conductive portion 142, and the third conductive portion 143. Circuit wirings (not shown) electrically connected to the first conductive portion 141, the second conductive portion 142, and the third conductive portion 143 are formed on the surface of the substrate 16. The substrate 16 may also support circuit elements other than the LED 10.

[0062] The LED element 10 includes a light reflecting portion 17. The light reflecting portion 17 is configured to hold at least the side surfaces of the opto-semiconductor laminate 11, the insulating portion 12, the light transmissive layer 13, the first conductive portion 141, the second conductive portion 142, the third conductive portion 143, and the wavelength conversion layer 15. The light reflecting portion 17 is formed by curing a transparent electrically insulating material in which a light scattering material such as alumina or tungsten oxide is dispersed. The light reflecting portion 17 is configured to reflect the light emitted from the side surfaces of the opto-semiconductor laminate 11, the light transmissive layer 13, and the wavelength conversion layer 15 toward the outside and return it to the inside of the wavelength conversion layer 15. Thereby, the utilization efficiency of the light emitted from the upper surface of the wavelength conversion layer 15 can be improved. As an example of the transparent material, silicone resin, epoxy resin, etc. can be cited.

[0063] The area of the first region R1 as observed from the stacking direction is smaller than the area of the second region R2 as observed from the same direction. Accordingly, the density of the current flowing through the first region R1 is higher than the density of the current flowing through the second region R2. As a result, as Figure 2 shown, the light intensity per unit area of the light L1 emitted from the light emitting layer 113 of the first region R1 is higher than the light intensity per unit area of the light L2 emitted from the light emitting layer 113 of the second region R2. The unit of the light intensity per unit area is [W / mm 2 . The light intensity per unit area may also be referred to as the light energy per unit area or the photon amount per unit area.

[0064] That is, the optoelectronic semiconductor laminate 11 formed of the p-type semiconductor layer 111, the n-type semiconductor layer 112, and the light emitting layer 113 is divided by the insulating portion 12 into the first region R1 and the second region R2 having different areas, whereby a decrease in the luminous efficiency for obtaining a given light beam can be suppressed, and lights L1 and L2 having different light intensities per unit area can be obtained without increasing the area of the light transmissive layer 13. In other words, an LED element can be provided which has a light emitting surface that exhibits a contrast in brightness as a single unit while suppressing a decrease in the luminous efficiency and an increase in the element size.

[0065] Figure 3 A vehicle 40 equipped with a headlamp device 30 according to one embodiment is illustrated. The headlamp device 30 is mounted at the left front corner and the right front corner of the vehicle 40. The headlamp device 30 is configured to illuminate an illuminated area located in front of the vehicle 40. The shape of the vehicle 40 is merely an example. The vehicle 40 is an example of a moving body.

[0066] Figure 4 The appearance of a headlamp device 30 according to one embodiment is illustrated. Figure 5 An illustration is made of a cross-section as observed from the arrow direction along the line V-V in Figure 4 . The headlamp device 30 includes a housing 31 and a light transmissive cover 32. The housing 31 and the light transmissive cover 32 define a lamp chamber 33.

[0067] The headlamp device 30 includes a lamp unit 34. The lamp unit 34 is disposed in the lamp chamber 33. The lamp unit 34 includes the above-described LED element 10 as a light source. The lamp unit 34 has a reflector 35. The reflector 35 is disposed on the traveling path of the light emitted from the LED element 10. The reflector 35 has a reflecting surface 351 having a shape based on a paraboloid. The light emitting surface of the LED element 10 is disposed at the focus of the reflecting surface 351 or in the vicinity thereof.

[0068] Figure 6The low beam pattern LPA related to the comparative example is shown. The light emitted from the conventional LED element with uniform brightness of the light emitted from the light emitting surface is reflected by the reflector 35, and thus the low beam pattern LPA is formed in front of the vehicle 40. The low beam pattern LPA is a light distribution pattern formed by the light emitted to the portion of the illuminated area located at a relatively short distance from the vehicle 40.

[0069] The reference numeral H represents the horizontal reference line. The reference numeral V represents the vertical reference line. The horizontal reference line H is orthogonal to the vertical reference line V.

[0070] The low beam pattern LPA determines its shape in such a way as not to cause glare to a moving body located in front of the vehicle 40. Specifically, the low beam pattern LPA includes a first cut-off line CL1 and a second cut-off line CL2. The first cut-off line CL1 and the second cut-off line CL2 form at least a part of the upper edge of the low beam pattern LPA.

[0071] The first cut-off line CL1 extends parallel to the horizontal reference line H. The low beam pattern LPA is positioned such that the first cut-off line CL1 is at least located in the oncoming lane. The second cut-off line CL2 extends obliquely upward from one end of the first cut-off line CL1. The low beam pattern LPA is positioned such that the second cut-off line CL2 is at least located in the own lane.

[0072] As Figure 7 shown in the example, the reflecting surface 351 of the reflector 35 includes a first area 351a, a second area 351b, a third area 351c, a fourth area 351d, a fifth area 351e, and a sixth area 351f. These areas are each formed as a smooth curved surface. Adjacent areas are connected to each other via steps and creases.

[0073] As Figure 6 shown in the example, the low beam pattern LPA includes a first projection image P1, a second projection image P2, a third projection image P3, a fourth projection image P4, a fifth projection image P5, and a sixth projection image P6.

[0074] The first projection image P1 is formed by the light emitted from the light source being reflected by the first area 351a of the reflector 35. The first projection image P1 has a shape that contributes to the formation of the first cut-off line CL1. In other words, the position and shape of the first area 351a are determined to be able to form the first projection image P1 with a prescribed shape at a prescribed position.

[0075] The second projection image P2 is formed by the light emitted from the light source being reflected by the second area 351b of the reflector 35. The second projection image P2 has a shape that contributes to the formation of the first cut-off line CL1. In other words, the position and shape of the second area 351b are determined to be able to form the second projection image P2 with a prescribed shape at a prescribed position.

[0076] The third projection image P3 is formed by the light emitted from the light source being reflected by the third region 351c of the reflector 35. The third projection image P3 has a shape that contributes to the formation of the first light and dark cut-off line CL1. In other words, the position and shape of the third region 351c are determined so as to be able to form the third projection image P3 having a prescribed shape at a prescribed position.

[0077] The fourth projection image P4 is formed by the light emitted from the light source being reflected by the fourth region 351d of the reflector 35. The fourth projection image P4 has a shape that contributes to the formation of the second light and dark cut-off line CL2. In other words, the position and shape of the fourth region 351d are determined so as to be able to form the fourth projection image P4 having a prescribed shape at a prescribed position.

[0078] The fifth projection image P5 is formed by the light emitted from the light source being reflected by the fifth region 351e of the reflector 35. The fifth projection image P5 has a shape that contributes to the formation of the second light and dark cut-off line CL2. In other words, the position and shape of the fifth region 351e are determined so as to be able to form the fifth projection image P5 having a prescribed shape at a prescribed position.

[0079] The sixth projection image P6 is formed by the light emitted from the light source being reflected by the sixth region 351f of the reflector 35. The sixth projection image P6 has a shape that contributes to the formation of the second light and dark cut-off line CL2. In other words, the position and shape of the sixth region 351f are determined so as to be able to form the sixth projection image P6 having a prescribed shape at a prescribed position.

[0080] That is, the low beam pattern LPA is formed by overlapping the first projection image P1, the second projection image P2, the third projection image P3, the fourth projection image P4, the fifth projection image P5, and the sixth projection image P6. The portion where more projection images are overlapped has a higher luminous intensity.

[0081] Figure 8 The state in which the light L1 and the light L2 emitted from the LED element 10 of the present embodiment are reflected by a specific region in the reflection surface 351 of the reflector 35 is shown. The reference sign A indicates the optical axis corresponding to the intersection point of the Figure 6 illustrated horizontal reference line H and vertical reference line V.

[0082] Figure 9 The low beam pattern LP formed in front of the vehicle 40 by the LED element 10 and the reflector 35 is exemplified. For elements that are substantially the same as the Figure 7 illustrated low beam pattern LPA, the same reference signs are given, and redundant explanations are omitted.

[0083] As Figure 1In the example shown, the first region R1 of the LED element 10 is located closer to one end edge 150a of the light-emitting surface 150 in the arrangement direction than to the center of the light-emitting surface 150 in the same direction. As Figure 8 In the example shown, the arrangement of the LED elements 10 in the headlamp device 30 is set such that the one end edge 150a corresponds to the upper end edge of the low beam pattern LP.

[0084] As a result, the light L1 emitted from the light-emitting layer 113 in the first region R1 passes through a position closer to the optical axis A than the light L2 emitted from the light-emitting layer 113 in the second region R2. As a result, as Figure 9 In the example shown, in the low beam pattern LP, a region with a higher luminous intensity is locally formed near the upper end edge.

[0085] Specifically, the light L1 emitted from the first region R1 is used to form the first high-luminance projection image P1a, the second high-luminance projection image P2a, and the third high-luminance projection image P3a in such a way that they are adjacent to the first projection image P1, the second projection image P2, and the third projection image P3 formed by the light L2 emitted from the second region R2, respectively, and form a part of the first light and dark cut-off line CL1.

[0086] Similarly, the light L1 emitted from the first region R1 is used to form the fourth high-luminance projection image P4a, the fifth high-luminance projection image P5a, and the sixth high-luminance projection image P6a in such a way that they are adjacent to the fourth projection image P4, the fifth projection image P5, and the sixth projection image P6 formed by the light L2 emitted from the second region R2, respectively, and form a part of the second light and dark cut-off line CL2.

[0087] Therefore, by using the LED element 10 of the present embodiment as the light source of the headlamp device 30, it is possible to form a light distribution pattern in which the luminous intensity is locally increased near the upper end edge of the low beam pattern LP in front of the vehicle 40 while maintaining the amount of the light beam. As a result, the far visibility of the low beam pattern LP formed by the headlamp device 30 can be improved. There is no need to make a special change to the structure of the reflector 35 to obtain such a light distribution pattern, nor is it necessary to use a plurality of LED elements with different luminous intensities. Therefore, it is possible to suppress the enlargement and complication of the optical system of the headlamp device 30.

[0088] As Figure 8As exemplified, with respect to the light in a specific region of the reflecting surface 351 of the reflector 35, the posture of the LED element 10 in the headlamp device 30 is determined such that the light L1 emitted from the first region R1 is incident on this region at a position farther from the LED element 10 than the light L2 emitted from the second region R2. The "specific region" is a region having an arbitrary area and shape set on the reflecting surface 351. Each of the above-mentioned first region 351a, second region 352b, third region 353c, fourth region 351d, fifth region 351e, and sixth region 351f can be an example of the specific region.

[0089] However, as long as the light L1 and the light L2 incident on the reflecting surface 351 can satisfy the above-mentioned positional relationship, by interposing an appropriate optical system between the LED element 10 and the reflector 35, the posture of the LED element 10 in the headlamp device 30 can also be appropriately changed.

[0090] As long as one end edge 150a of the light emitting surface 150 of the LED element 10 corresponds to the upper end edge of the low beam pattern LP, by interposing an appropriate optical system after the reflector 35, the above-mentioned positional relationship between the light L1 and the light L2 incident on the reflecting surface 351 can also be appropriately changed.

[0091] Figure 10 The structure of the headlamp device 30 of another embodiment is exemplified. The headlamp device 30 includes a housing 31 and a light transmissive cover 32. The housing 31 and the light transmissive cover 32 define a lamp chamber 33.

[0092] The headlamp device 30 includes a lamp unit 34. The lamp unit 34 is disposed in the lamp chamber 33. The lamp unit 34 includes the above-mentioned LED element 10 as a light source. The lamp unit 34 has a reflector 35 and a projection lens 36.

[0093] The reflector 35 is disposed on the traveling path of the light emitted from the LED element 10. The reflector 35 has a reflecting surface 351 having a shape based on an ellipsoidal surface. The projection lens 36 is disposed such that its rear focal point is located at or near the first focal point of the reflecting surface 351. The light emitting surface of the LED element 10 is disposed at or near the second focal point of the reflecting surface 351.

[0094] Figure 11 The low beam pattern LPA of the comparative example is shown. The light emitted from a conventional LED element with uniform brightness of the light emitted from the light emitting surface is reflected by the reflector 35, thereby forming a low beam pattern LPA in front of the vehicle 40. The low beam pattern LPA is a light distribution pattern formed by the light emitted to the portion of the illuminated area located at a relatively short distance from the vehicle 40.

[0095] Reference numeral H represents a horizontal reference line. Reference numeral V represents a vertical reference line. The horizontal reference line H is orthogonal to the vertical reference line V.

[0096] The low beam pattern LPA is shaped so as not to cause glare to a moving object in front of the vehicle 40. Specifically, the low beam pattern LPA includes a first light and dark cut-off line CL11, a second light and dark cut-off line CL12, and a third light and dark cut-off line CL13. The first light and dark cut-off line CL11, the second light and dark cut-off line CL12, and the third light and dark cut-off line CL13 form at least a part of the upper edge of the low beam pattern LPA.

[0097] The first light and dark cut-off line CL11 extends parallel to the horizontal reference line H. The low beam pattern LPA is positioned such that the first light and dark cut-off line CL11 is at least located in the oncoming lane. The second light and dark cut-off line CL12 extends parallel to the horizontal reference line H above the first light and dark cut-off line CL11. The low beam pattern LPA is positioned such that the second light and dark cut-off line CL12 is at least located in the own lane. The third light and dark cut-off line CL13 extends obliquely so as to connect one end of the first light and dark cut-off line CL11 and the second light and dark cut-off line CL12 to each other.

[0098] As Figure 10 shown in the example, the lamp unit 34 includes a light shield 37. A part of the light emitted from the LED element 10 and reflected by the reflector 35 is blocked by the light shield 37. Although not shown in the figure, the light shield 37 has an upper edge with a shape corresponding to the first light and dark cut-off line CL11, the second light and dark cut-off line CL12, and the third light and dark cut-off line CL13. The light passing through a position above the upper edge of the light shield 37 is projected forward of the vehicle 40 by the projection lens 36 to form the low beam pattern LPA. That is, the light shield 37 defines the shape of the upper edge of the low beam pattern LPA.

[0099] Figure 12 The state in which the light L1 and the light L2 emitted from the LED element 10 of the present embodiment are reflected by a specific area in the reflecting surface 351 of the reflector 35 is shown. Reference numeral A represents the optical axis corresponding to the Figure 11 intersection of the horizontal reference line H and the vertical reference line V in the shown example.

[0100] Figure 13 The low beam pattern LP formed in front of the vehicle 40 by the LED element 10 and the reflector 35 is exemplified. For elements substantially the same as the Figure 11 low beam pattern LPA in the shown example, the same reference numerals are assigned, and repeated descriptions are omitted.

[0101] As Figure 1In the example shown, the first region R1 of the LED element 10 is located closer to one end edge 150a of the light emitting surface 150 in the arrangement direction than to the center of the light emitting surface 150 in the same direction. As Figure 12 In the example shown, the arrangement of the LED element 10 in the headlamp device 30 is determined such that a part of the light L1 emitted from the light emitting layer 113 in the first region R1 is blocked by the light shielding cover 37.

[0102] Thereby, the light L1 emitted from the light emitting layer 113 in the first region R1 passes through a position closer to the optical axis A than the light L2 emitted from the light emitting layer 113 in the second region R2. As a result, as Figure 13 In the example shown, in the low beam pattern LP, a region with a higher luminous intensity is locally formed near the upper end edge.

[0103] Specifically, the low beam pattern LP includes a first projection image P11 and a second projection image P12. The first projection image P11 is a projection image formed by the light L1 emitted from the first region R1. The second projection image P12 is a projection image formed by the light L2 emitted from the second region R2. The luminous intensity of the first projection image P11 is higher than that of the second projection image P12. The first projection image P11 is formed adjacent to the second projection image P12 and includes a first cut-off line CL11, a second cut-off line CL12, and a third cut-off line CL13.

[0104] Therefore, by using the LED element 10 of the present embodiment as the light source of the headlamp device 30, it is possible to form a light distribution pattern in which the luminous intensity is locally increased near the upper end edge of the low beam pattern LP while maintaining the amount of light beam in front of the vehicle 40. Thereby, the far visibility of the low beam pattern LP formed by the headlamp device 30 can be improved. In order to obtain such a light distribution pattern, it is not necessary to particularly change the structure of the reflector 35, nor is it necessary to use a plurality of LED elements with different luminous intensities. Therefore, it is possible to suppress the enlargement and complication of the optical system of the headlamp device 30.

[0105] As Figure 12 In the example shown, with respect to the light toward a specific region in the reflecting surface 351 of the reflector 35, the posture of the LED element 10 in the headlamp device 30 is determined such that the light L1 emitted from the first region R1 is incident on this region at a position farther from the projection lens 36 than the light L2 emitted from the second region R2. The "specific region" is a region having an arbitrary area and shape set on the reflecting surface 351.

[0106] According to such a structure, it is possible to easily reduce the amount of light blocked by the light shield 37. However, as long as the light L1 and the light L2 incident on the reflecting surface 351 satisfy the above-described positional relationship, by interposing an appropriate optical system between the LED element 10 and the reflector 35, it is possible to appropriately change the posture of the LED element 10 in the headlamp device 30.

[0107] Each of the structures described above is merely an example for facilitating the understanding of the present invention. Each structural example can be appropriately changed and combined with other structural examples.

[0108] In the above-described embodiment, the n-type semiconductor layer 112 is closer to the light-transmitting layer 13 than the p-type semiconductor layer 111. However, as long as the light-emitting diode can achieve the desired function, the positional relationship between the p-type semiconductor layer 111 and the n-type semiconductor layer 112 with respect to the light-transmitting layer 13 can also be reversed.

[0109] In the above-described embodiment, the optical semiconductor laminate 11 is configured to function as a light-emitting diode. However, the optical semiconductor laminate 11 can also be configured to function as a laser diode or an electroluminescent element.

[0110] In the above-described embodiment, the wavelength conversion layer 15 is provided to obtain white light. However, depending on the relationship between the color of the light emitted from the light-emitting layer 113 and the color required as a light source, the wavelength conversion layer 15 can be omitted.

[0111] In the above-described embodiment, the headlamp device 30 is mounted on a vehicle 40 having four wheels. However, the headlamp device 30 can also be mounted on a two-wheeled motor vehicle or a three-wheeled motor vehicle. The form of the two-wheeled motor vehicle or the three-wheeled motor vehicle can be any one of a straddle type, a step type, and a standing type. The two-wheeled motor vehicle and the three-wheeled motor vehicle are also examples of moving bodies. The headlamp device 30 can also be mounted on a railway vehicle having four or more wheels. The railway vehicle is also an example of a moving body. The number of headlamp devices 30 mounted on the front portion of the moving body can be appropriately determined according to the specifications of the moving body.

[0112] As part of the content constituting the present invention, the contents of Japanese Patent Application No. 2022-195469 filed on December 7, 2022, and Japanese Patent Application No. 2022-195470 filed on December 7, 2022 are incorporated by reference.

Claims

1. A headlight device, characterized in that, Mounted on a moving body, the headlamp device includes: A semiconductor light-emitting element having a single-piece light-emitting surface; and A reflector having a reflecting surface with a shape based on a paraboloid, which reflects the light emitted from the light-emitting surface to form a low-beam light distribution pattern in front of the moving body. The light-emitting surface has a first portion and a second portion arranged in a first direction. The light intensity per unit area of the light emitted from the first portion is higher than that of the light emitted from the second portion. The first portion is located closer to one end edge of the light-emitting surface in the first direction than the center of the light-emitting surface in the first direction. The one end edge corresponds to the upper end edge of the low-beam light distribution pattern.

2. The headlamp device according to claim 1, wherein: Regarding the light from the semiconductor light-emitting element toward a specific region in the reflecting surface, the light emitted from the first portion is incident on a position in the specific region that is farther from the semiconductor light-emitting element than the light emitted from the second portion.

3. The headlamp device according to claim 1 or 2, wherein: The semiconductor light-emitting element includes: A first semiconductor layer having a first conductivity type; A second semiconductor layer having a second conductivity type opposite to the first conductivity type; A light-emitting layer located between the first semiconductor layer and the second semiconductor layer; An insulating portion that divides the first semiconductor layer, the second semiconductor layer, and the light-emitting layer into an electrically insulated first region and a second region; A light-transmitting layer having a single-piece structure that extends across the first region and the second region and allows the light emitted from the light-emitting layer to pass through; A first conductive portion electrically connected to the second semiconductor layer in the first region; A second conductive portion that electrically connects the first semiconductor layer in the first region to the second semiconductor layer in the second region; And A third conductive portion electrically connected to the first semiconductor layer in the second region; The first semiconductor layer, the second semiconductor layer, and the light-emitting layer are arranged in a second direction intersecting the first direction. The area of the first region as observed from the second direction is smaller than the area of the second region as observed from the second direction. The first portion faces the first region in the second direction. The second portion faces the second region in the second direction.

4. A headlamp device, characterized in that, Mounted on a moving body, the headlamp device has: A projection lens; A semiconductor light-emitting element having a single-piece light-emitting surface; A reflector having a reflecting surface with a shape based on an ellipsoid, which reflects the light emitted from the light-emitting surface and passes it through the projection lens, thereby forming at least a part of a low-beam light distribution pattern in front of the moving body; And A light shield that defines the shape of the upper edge of the low beam light distribution pattern by blocking a part of the light reflected by the reflector. The light emitting surface has a first part and a second part arranged in a first direction. The light intensity per unit area of the light emitted from the first part is higher than that of the light emitted from the second part. The first part is located closer to one edge of the light emitting surface in the first direction than the center of the light emitting surface in the first direction. A part of the light emitted from the first part is blocked by the light shield.

5. The headlight device according to claim 4, characterized in that Regarding the light from the semiconductor light emitting element towards a specific area in the reflecting surface, compared with the light emitted from the second part, the light emitted from the first part is incident on a position in the specific area that is farther from the projection lens.

6. The headlight device according to claim 4 or 5, characterized in that The semiconductor light emitting element includes: A first semiconductor layer having a first conductivity type; A second semiconductor layer having a second conductivity type opposite to the first conductivity type; A light emitting layer located between the first semiconductor layer and the second semiconductor layer; An insulating part that divides the first semiconductor layer, the second semiconductor layer, and the light emitting layer into an electrically insulated first area and a second area; A light transmissive layer having a single-piece structure that extends across the first area and the second area and allows the light emitted from the light emitting layer to pass through; A first conductive part that is electrically connected to the second semiconductor layer in the first area; A second conductive part that electrically connects the first semiconductor layer in the first area to the second semiconductor layer in the second area; A third conductive part that is electrically connected to the first semiconductor layer in the second area; The first semiconductor layer, the second semiconductor layer, and the light emitting layer are arranged in a second direction intersecting the first direction. The area of the first area as observed from the second direction is smaller than the area of the second area as observed from the second direction. The first part faces the first area in the second direction. The second part faces the second area in the second direction.

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