JP7665490B2 - Headlight, projection lens, and headlight control method - Google Patents

Description

The present invention relates to lighting technology for vehicle headlights, etc.

Headlights (or headlamps or headlights) for vehicles such as automobiles use multiple light sources to provide illumination in a desired light distribution pattern. Conventional headlights use semiconductor light source elements such as LEDs (Light Emitting Diodes) as the light source.

Vehicle headlights are required to increase the lighting effect in the area ahead of the vehicle, while also preventing dazzling vehicles in the area ahead of the vehicle, such as preceding and oncoming vehicles. One method for achieving light distribution that prevents dazzling is ADB (Adaptive Driving Beam) light distribution control (hereinafter sometimes simply referred to as ADB). ADB light distribution control is a technology that automatically controls the turning off or dimming of part of the high beam light distribution so as not to dazzle vehicles in the area ahead.

A headlight using multiple LEDs as light sources has been proposed as a headlight for achieving ADB light distribution control. In this headlight, multiple LEDs each illuminate different areas, and the ADB light distribution pattern is formed by combining these illuminated areas (hereinafter sometimes referred to as illumination areas). Furthermore, this headlight prevents dazzling the vehicle ahead by selectively turning off or dimming the illumination area where the vehicle ahead is located, and ensures forward visibility by using the illuminated illumination area.

In addition, there are also so-called bi-function headlights for automobiles that project low beam (front lights off for passing) and high beam (front lights off for driving) through the same optical lens.

An example of the prior art is Japanese Patent No. 5779028 (Patent Document 1). Patent Document 1 describes a light distribution control means for a headlamp that emits a light distribution pattern with limited illumination so as not to cause dazzle. The headlamp is equipped with optical elements arranged in a matrix and capable of controlling the amount of light reflected from the light source, thereby controlling the amount of light for each area in front of the vehicle.

Patent No. 5779028

Current bi-function headlight configurations include many mechanical control parts and optical components such as light guides. This makes it difficult to reduce costs and improve reliability with this configuration.

In addition, as an example of headlight technology for realizing ADB, there is a technology that attempts to form an ADB light distribution pattern using optical elements arranged in an array or matrix, as in Patent Document 1. There is also a technology that uses, for example, a micro LED array as the optical element. With this technology, it is possible to form a desired light distribution pattern in the illumination area in front of the vehicle. However, with such technology, the amount of light emitted from a light source (e.g., an LED) located in correspondence with the center of the illumination area in front of the vehicle is insufficient, resulting in an insufficient amount of light in the center of the illumination area in front of the vehicle, and it may be difficult to obtain a predetermined amount of light required for, for example, high beams.

The objective of the present invention is to provide lighting technology that can reduce costs, improve reliability, and ensure the amount of light in the center of the lighting area, thereby enabling the realization of suitable headlights, etc.

A representative embodiment of the present disclosure has the following configuration. The headlight of the embodiment includes an LED board on which a plurality of LED chips are arranged, an LED drive circuit that drives the plurality of LED chips on the LED board, and a projection lens that is arranged in a direction perpendicular to the LED board and projects light emitted from the LED board as a beam forward. The LED board includes a plate, the plurality of LED chips arranged on the plate and emitting light with wavelengths from purple to blue, and a phosphor that is arranged on the plate to cover the plurality of LED chips and emits yellow, red, and green light using the light with wavelengths from purple to blue as an excitation light source. Each of the plurality of LED chips on the plate is arranged at a predetermined position corresponding to the configuration of the forward illumination area so as to realize light distribution control of a pattern selected from a plurality of light distribution control patterns including low beam and high beam as light distribution control of a beam forward. The LED drive circuit controls the turning on and off and the light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern.

According to a representative embodiment of the present disclosure, it is possible to realize a suitable headlight or the like that can reduce costs, improve reliability, and ensure the amount of light in the center of the lighting area with respect to lighting technology. Problems, configurations, effects, etc. other than those described above are shown in [Form for carrying out the invention].

1 shows a schematic configuration of a headlight according to a first embodiment. 2 shows a configuration of a main surface of a patterned LED substrate according to the first embodiment. 1 shows a cross-sectional configuration of a patterned LED substrate according to a first embodiment. 4 shows a cross-sectional configuration of a patterned LED substrate according to a modified example of the first embodiment. 2 shows the configuration of a projection lens according to the first embodiment. 1 shows a configuration of an LED drive circuit according to a first embodiment. 2 shows a configuration example of an LED device of the LED chip according to the first embodiment. The following shows the configuration of regulations governing low beams for right-hand traffic. 3 shows a configuration of a first pattern (normal low-beam light distribution control) according to the first embodiment. 4 shows a configuration of a second pattern (normal high beam light distribution control) according to the first embodiment. 13 shows a configuration of a third pattern (high beam+ADB light distribution control) according to the first embodiment. 13 shows a configuration of a fourth pattern (high beam+variable light distribution width control) according to the first embodiment. 13 shows a configuration of a fifth pattern (high beam+variable light distribution center control) according to the first embodiment. 13 shows the configuration of a sixth pattern (lighting when cornering) according to the first embodiment. 13 shows the configuration of a seventh pattern (white line emphasis in rainy weather) according to the first embodiment. 1 shows a configuration example of light distribution control using an LED array in a comparative example to the first embodiment.

Below, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same parts are generally given the same reference numerals, and repeated explanations will be omitted. In the drawings, the representation of components may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention.

[Comparative Example]
FIG. 16 is an explanatory diagram of a headlight technology of a comparative example with respect to the first embodiment. FIG. 16A shows an outline of an ADB unit with an LED array constituting a headlight of the comparative example. In this ADB unit, an LED array 1601 is arranged on the main surface of a substrate. In the LED array 1601, a plurality of LED devices 1602 are arranged vertically and horizontally in a matrix. In (A), the enlarged portion shows a portion of 4×12 LED devices 1602. Note that in (A), each LED device 1602 is shown as a square of the same size, but in reality, each LED device 1602 may be arranged in a different size or shape. The turning on/off of each LED device 1602 can be controlled from an LED drive circuit.

Figure 16 (B) is a schematic diagram showing an example of the configuration of an illumination area in front of the vehicle based on the configuration of the LED array 1601 in (A). The line h-h corresponds to the horizontal line. For ease of understanding, an example of the vehicle's lane 1604 and beam area (corresponding to the zones in Figure 8) is also shown. The illumination area 1603 is configured as a lattice corresponding to the LED array 1601. Each square in the lattice corresponds to an illumination area by each LED device 1602.

A comparative headlight using such an LED array 1601 realizes a light distribution pattern as ADB light distribution control in an illumination area 1603 by controlling the light emission of each LED device 1602 of the ADB unit. An example of an ADB light distribution pattern is one in which, when there is an oncoming vehicle ahead in the oncoming lane 1605 to the left of the vehicle's lane 1604, an area 1607 corresponding to the oncoming vehicle is turned off or dimmed. A number of LEDs (e.g., 9 LEDs, 3 x 3) associated with that area 1607 are turned off.

However, in the headlight of this comparative example, since the LED array 1601 is configured with the LED devices 1602 uniformly arranged, the amount of illumination in the center of the illumination area 1603 (e.g., area 1608) may be insufficient. This insufficiency may result in failure to meet the requirements for a high beam or the like, or in failure to achieve a suitable high beam or the like.

<First embodiment>
A headlight according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 15. FIG.

The headlight of the first embodiment shown in Fig. 1 etc. includes a patterned LED substrate 2 having multiple LED chips that emit blue light arranged on a plate 61, and phosphor 21 that emits yellow or red and green light using the purple to blue wavelength light from the LED chips as an excitation light source and that is applied to the plate 61 (Fig. 2). The positions of the multiple LED chips (LED chips 22 to 42) on the plate 61 of the patterned LED substrate 2 (in other words, the main surface; a plane perpendicular to the optical axis) are designed in advance according to the design of the desired light distribution pattern in the illumination area in front of the vehicle.

Furthermore, the patterned LED substrate 2 has shielding plates (shielding plates 43 to 58) arranged between the LED chips (between the LED chips at predetermined positions) on the plate 61 as boundaries that limit the excitation range of the phosphor 21 and block the light emitted by the LED chips. With this configuration, the headlight of the first embodiment controls the amount of light emitted by each LED chip, and low beam, high beam, ADB light distribution controlled high beam, and the like are set on the plate 61 as light distribution control (in other words, light distribution pattern) for the illumination area in front of the vehicle. The headlight of the first embodiment realizes light distribution of a desired light distribution pattern that has been controlled and selected by projecting the light emitted from the patterned LED substrate 2, in which such light distribution on the plate 61 has been set, as a beam toward the front of the vehicle using the projection lens 1 (Figure 1).

The arrangement of the LED chips and the shielding plates acting as boundaries on the patterned LED board 2 can be freely set according to the design of the light distribution pattern for the illumination area in front of the vehicle. As an example of setting and designing a light distribution pattern, a shielding plate is placed on the main surface of the patterned LED board 2 associated with the illumination area at positions corresponding to the left and right white lines of the lane in which the vehicle is traveling. With this light distribution pattern, it becomes possible to control the light distribution using the left and right white lines as areas (Figure 15).

According to the configuration of the headlight of the first embodiment, the light distribution in front of the vehicle is controlled to mask (in other words, selectively turn off or dim) the beam toward oncoming vehicles, etc., so as not to dazzle the driver of the oncoming vehicle, etc., and patterns such as low beam, high beam, and high beam with ADB can be switched. Therefore, the headlight of the first embodiment can achieve various functions such as low beam, high beam, glare prevention by ADB, and white line emphasis, all in one headlight unit, without using multiple mechanical parts or a large number of optical elements (e.g., an LED array).

In addition, the headlight configuration of the first embodiment can realize a light distribution pattern that corresponds to the case (corresponding mode), such as when it is desired to control the light distribution toward the shoulder of the road rather than toward the oncoming vehicle depending on the ADB control and the distance between the vehicle and the oncoming vehicle, or when it is desired to brightly illuminate the white lines on the road in rainy weather. Therefore, according to the first embodiment, it is possible to improve the driver's visibility of important areas, enabling safer driving.

[Headlight]
Fig. 1 is a perspective view showing a schematic configuration of a headlight according to the first embodiment. The headlight according to the first embodiment includes a heat sink 3, a patterned LED substrate 2 provided on the heat sink 3, an LED drive circuit 4 electrically connected to the patterned LED substrate 2, and a projection lens 1 disposed forward (Z direction in Fig. 1) with respect to a main surface 2A of the patterned LED substrate 2. These components are fixed to a housing (not shown) of the headlight in a predetermined positional relationship. This headlight projects light emitted from the patterned LED substrate 2 as a beam by the projection lens 1 forward of the vehicle (indicated by an arrow).

For the sake of explanation, X, Y, and Z may be used as directions and a coordinate system. In FIG. 1, the Z axis is the direction of the headlight illumination (beam) and the direction of the optical axis of the light emitted (emitted light) from the patterned LED substrate 2. The X and Y axes are directions perpendicular to the Z axis and are two orthogonal directions that constitute the main surface 2A (plane on which multiple LED chips are arranged) of the patterned LED substrate 2. In particular, the X axis corresponds to the horizontal direction, the lateral direction within the main surface 2A, and the Y axis corresponds to the vertical direction, the longitudinal direction within the main surface 2A.

The heat sink 3 is arranged in contact with the rear side of the main surface 2A of the patterned LED substrate 2 in order to dissipate heat from the patterned LED substrate 2.

The patterning LED substrate 2 is an LED substrate in which multiple LED chips are arranged at predetermined positions on the main surface 2A (on the corresponding plate 61) to form a predetermined pattern shape, as shown in FIG. 2 described later. The light emitted (emitted light) including the light emitted from each LED chip of the patterning LED substrate 2 has an optical axis in the Z direction shown by the dashed line in FIG. 1, and travels toward the projection lens 1.

The LED drive circuit 4 is mounted on a substrate separate from the patterning LED substrate 2, and is electrically connected to the patterning LED substrate 2 via wiring (which may be implemented, for example, on a flexible printed circuit board). As a modified example, the LED drive circuit 4 may be integrally mounted with the patterning LED substrate 2.

The same rule can be applied to the two headlights installed on the left and right sides of the front of the vehicle.

[Patterning LED Substrate]
Fig. 2 shows an XY plan view of the main surface 2A of the patterning LED substrate 2. In Fig. 2, the main surface 2A of the patterning LED substrate 2 is shown as a plan view from back to front in the Z direction (in other words, the front-rear direction) in Fig. 1, corresponding to a case where a person views the illumination area in front of the vehicle from inside the vehicle.

As shown in FIG. 2, the patterned LED substrate 2, when viewed from the main surface 2A, has a plate 61, LED chips 22, 23, ..., 41, 42 as a plurality of LED chips arranged in a predetermined pattern shape at predetermined positions on the plate 61, phosphor 21 formed in a predetermined area so as to cover the plurality of LED chips, and shielding plates 43, 44, ..., 57, 58 as a plurality of shielding plates arranged between predetermined LED chips of the plurality of LED chips.

In this example, the plate (substrate) 61 is a rectangular substrate that is long horizontally in the X direction. This long horizontal length corresponds to the roughly horizontal length of the illumination area (the area to be irradiated with the beam) in front of the vehicle.

The LED chips are roughly divided into nine LED chips (first LED chip group) arranged on a first line 2B extending in the X direction indicated by a dashed line, namely LED chips 22, 23, 24, 25, 26, 27, 28, 29, 30, and twelve LED chips (second LED chip group) arranged on a second line 2C extending in the X direction indicated by a dashed line, namely LED chips 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42.

In the first LED chip group, LED chip 26 is placed in the central position indicated by the dashed line. The central position corresponds to the center of the headlight in the X direction. Four LED chips (22-25, 27-30) are placed symmetrically on the left and right of central LED chip 26, at predetermined intervals and in predetermined positions.

In the second LED chip group, an LED chip 35 is arranged in the center position indicated by the dashed line. Seven LED chips (36-42) are arranged at a predetermined interval and in a predetermined position on the right side of the central LED chip 35. Three LED chips (32-34) are arranged at a predetermined interval and in a predetermined position on the left side of the central LED chip 35. Also, one LED chip 31 is arranged near the lower left of the central LED chip 35. In this way, in the second LED chip group, multiple LED chips are arranged asymmetrically. This arrangement corresponds to the difference in the shape of the area to be illuminated on the left and right in the illumination area in front of the vehicle, as will be described later (FIG. 8). The density and number of the LED chips on the right side and the LED chips on the left side of the second LED chip group are also different, with the density and number being greater on the right side.

The phosphor 21 is formed in a predetermined area that, in this example, is convex in the Y direction so as to cover all of the LED chips. This convex shape corresponds to the illumination area in front of the vehicle being roughly convex. The convex area above the second line 2C roughly corresponds to the illumination area above the horizontal line described below (Figure 8).

The multiple shielding plates include shielding plates 43, 44, 45, and 46 that are obliquely shaped (diagonal to the X-axis and Y-axis) and are arranged near the left and right end LED chips 22 and 30 relative to the first LED chip group, and shielding plates 47, 48, 49, and 50 that extend in an oblique shape and are arranged near the left and right LED chips 25 and 27 relative to the central LED chip 26.

The shielding plates 43, 44, 45, and 46 near the left and right ends are formed to correspond to the pattern at the time of cornering described later. In detail, the shielding plate at the left end has a shielding plate 43 arranged to extend obliquely from the upper left corner of the phosphor 21 area toward the center on the upper side in the Y direction relative to the LED chip 22 at the left end, and a shielding plate 44 arranged to extend obliquely from the lower left corner of the phosphor 21 area toward the center on the lower side in the Y direction relative to the LED chip 22 at the left end. The extension of the shielding plates 43 and 44 is approximately to the middle between the LED chip 22 and the adjacent LED chip 23. Similarly, the shielding plate at the right end has a shielding plate 46 arranged to extend obliquely from the upper right corner of the phosphor 21 area toward the center on the upper side in the Y direction relative to the LED chip 30 at the right end, and a shielding plate 45 arranged to extend obliquely from the lower right corner of the phosphor 21 area toward the center on the lower side in the Y direction relative to the LED chip 22 at the right end. The shielding plates 45 and 46 extend to about the middle between the LED chip 30 and the adjacent LED chip 29.

The left and right shielding plates 47, 48, 49, and 50 are formed to correspond to the left and right white line patterns described below. Between the central LED chip 26 and its adjacent LED chip 25 on the left, a shielding plate 48 is arranged, which extends diagonally from the lower left to the upper right toward the center of the area. Between the adjacent LED chip 25 and its adjacent LED chip 24 on the further left, a shielding plate 47 is arranged to the upper left of the shielding plate 48, which extends diagonally from the lower left to the upper right toward the center of the area. These two shielding plates 47, 48 have a shape that corresponds to the white line area on the left side of the vehicle's lane in the illumination area. The LED chip 25 is arranged in the left white line area, sandwiched between the two shielding plates 47, 48.

Similarly, a shielding plate 49 is disposed between the central LED chip 26 and its adjacent LED chip 27 to the right, extending obliquely from the lower right to the upper left toward the center of the area. Furthermore, a shielding plate 50 is disposed between the adjacent LED chip 27 to the right and its adjacent LED chip 28 to the further right, to the upper right of the shielding plate 49, extending obliquely from the lower right to the upper left toward the center of the area. These two shielding plates 49, 50 have a shape that corresponds to the area of the white line on the right side of the vehicle's lane in the illumination area. The LED chip 27 is disposed in the area of the white line on the right side, sandwiched between the two shielding plates 49, 50.

The multiple shielding plates include shielding plates 52, 53, 54, 55, 56, 57, and 58 extending in the Y direction and arranged to separate the LED chips from the central LED chip 35 to the LED chip 42 at the right end, and shielding plate 51 arranged to separate the LED chips 36 and 37 on the right side from the central LED chip 35 and the LED chips 31 and 34 on the left side.

Specifically, the shielding plate 51 is made up of three parts: a shielding plate section arranged to extend in the X direction below the LED chips 35, 36, and 37 in the Y direction; a shielding plate section arranged to extend in the X direction above the left LED chip 34 in the Y direction; and a shielding plate section arranged diagonally between the central LED chip 35 and the lower left LED chip 31 to connect these shielding plate sections.

For the LED chips on the right side of the central LED chip 35, the three shielding plates 52, 53, and 54 extending in the Y direction extend to and stop at the shielding plate 51. In addition, the four shielding plates 55, 56, 57, and 58 extending in the Y direction extend to and stop at the diagonal shielding plate 50.

[Patterning LED Substrate]
Fig. 3 shows an XZ plan view as a cross-sectional view of the patterned LED substrate 2 of Fig. 2 taken along line A-A. In the Z direction, silicon grease 62 for improving thermal conductivity is applied to the surface of the heat sink 3, and a plate 61 is disposed via the silicon grease 62. Metal foil wiring (e.g., metal foil wiring 63-68) for connecting the LED chips and resist 60 are formed on the surface of the plate 61. LED chips (e.g., LED chips 25, 26, 27) are connected to the metal foil wiring.

For example, shielding plates 48, 49 are formed between the LED chips 25, 26, 27 so as to stand in the Z direction. The shielding plates 48, 49 are formed so as to stand like walls in the Z direction from the surface of the resist 60 to the surface 21a of the phosphor 21. In the configuration example of FIG. 3, the height of the shielding plates 48, 49 is the same as the thickness 301 of the phosphor 21. All the shielding plates are formed in the same manner, with a height up to the surface 21a of the phosphor 21.

The characteristics of light emitted from an LED chip will be described using the illustrated LED chip 27 as an example. Light emitted 70 from the LED chip 27 is blue light as LED excitation light. Light emitted 76 from the LED chip 27 is also blue light as LED excitation light. For the sake of explanation, the light is shown divided into two parts, light emitted 70 and light emitted 76. One of the blue lights, light emitted 70, excites the phosphor 21 and generates yellow light as light emitted 73. The yellow light light emitted 73 is emitted forward (Z direction) from the surface 21a of the phosphor 21. The other blue light light, light emitted 76, is a component that passes through the phosphor 21 as it is and is emitted forward from the surface 21a of the phosphor 21. In this way, part of the light emitted from the LED chip is converted to yellow light by excitation and emitted, and the other part is emitted as blue light.

The light emitted forward from the surface 21a of the phosphor 21 is a combination of these two types of light emission 73, 76, and becomes white light 302 by combining blue light and yellow light. This white light 302 becomes the light emitted from the patterned LED substrate 2. This white light 302 is designed to meet the requirements for luminous intensity, such as low beam, stipulated by regulations described below.

Similarly, the LED chip 27 also emits light in a forward diagonal direction. For example, it has light emission 72 and light emission 78 with a certain divergence angle. When light emission 72 is not blocked by a shielding plate, it becomes light emission 75, which is yellow light, upon excitation and is emitted from the surface 21a of the phosphor 21. When light emission 78 is not blocked by a shielding plate, it is emitted as it is from the surface 21a of the phosphor 21 as blue light.

It also has light emission 71 and light emission 77 with a certain divergence angle. Light emission 71 becomes light emission 74, which is yellow light, when excited. These lights emission 74 and 77 are shielded by shielding plate 49. Shielding plate 49 is disposed at a predetermined position between the central LED chip 26 and the LED chip 27 to the right of it. Shielding plate 49 is disposed at a first distance from LED chip 26 and at a second distance from LED chip 27. Note that there is also a shielding plate 50 on the right side of LED chip 27 as shown in FIG. 2, but it is omitted in FIG. 3.

The shielding plate blocks the light emitted from the LED chip. For example, the shielding plate 49 blocks both the light emitted 74 (yellow light) and the light emitted 77 (blue light) from the LED chip 27. As a result, for example, the light emitted from the LED chip 27 in FIG. 2 mainly illuminates the right-side white line corresponding to the area divided by the left shielding plate 49 and the right shielding plate 50 in the forward illumination area. The light emitted from the LED chip 27 is restricted in divergence in accordance with the shielding by the shielding plate 49, so that the amount of light that reaches the area corresponding to the vehicle's lane including the LED chip 26 in FIG. 2 is reduced.

For example, light emitted from the LED chip 25 on the left side is similarly blocked by the right shielding plate 48 and the left shielding plate 47 in FIG. 2. As a result, the light emitted from the LED chip 25 in FIG. 2 mainly illuminates the left white line corresponding to the area divided by the left shielding plate 47 and the right shielding plate 48.

For example, light emitted from the central LED chip 26 is similarly blocked by the right shielding plate 49 and the left shielding plate 48. The diagonal dashed lines in the figure indicate the divergence angle at which the light emitted from the LED chip 26 is not blocked by the shielding plates 49, 48, in other words, the effective excitation range and divergence range limited by the shielding plates. As a result, the light emitted from the LED chip 26 in FIG. 2 mainly illuminates the vehicle lane corresponding to the area divided by the left shielding plate 48 and the right shielding plate 49.

Similarly, the other LED chips in FIG. 2 mainly illuminate the area divided by the shielding plate. As shown in FIG. 2, the area divided by the shielding plate may have various areas, such as only one LED chip, two or more LED chips, or no LED chip. In the configuration example of FIG. 2, the space (the area of the corresponding phosphor 21) is not completely divided by the shielding plate, but is roughly divided into a plurality of spaces (corresponding areas). The light emitted from a certain LED chip may diverge outward through a portion where there is no shielding plate. The divergent light also forms an illumination area. For example, the shielding plate 49 extends from a position slightly away from the lower side of the phosphor 21 area in FIG. 2, diagonally upward to the left, toward the LED chip 35 at the center of the second line 2C, to a position slightly away so as not to come into contact with the shielding plate 51. The light emitted from the LED chip 26 diverges around the entire periphery in the X-Y plane in FIG. 2 with the Z direction as the optical axis, but some of the light is blocked by the shielding plate 49, etc., and the other part is emitted forward so as to diverge outward from places where there is no shielding plate 49, etc.

Without being limited to this, as a variant, the space above the plate 61 may have an area that is completely partitioned by a shielding plate in the XY plane (in other words, a closed area).

The division of the illumination area in front of the vehicle in FIG. 2 into multiple regions is designed based on the position of each LED chip, the position, shape, height, etc. of each shielding plate, as described above. Note that the configuration of the physical division of multiple regions on the surface of plate 61 in FIG. 2 by shielding plates, etc., and the configuration of the multiple regions in the illumination area in front of the vehicle (areas actually irradiated by the beam, distribution of luminous intensity) are not strictly the same due to forward divergence, but they correspond to each other, and the configuration of the illumination area is similar to the configuration by shielding plates, etc.

The optical shielding property of the shielding plate may be, in detail, either absorption, reflection, or other property. This shielding property may be a property that realizes the function of limiting the spread of light emitted from the LED chip (among which, the LED device described below), that is, the spread in the lateral direction (X-Y plane) relative to the direction toward the front of the vehicle (Z axis). The material and manufacturing method of the shielding plate are not limited, but as an example, the shielding plate may be formed of a base material coated with a black film (in other words, a light-shielding film). Alternatively, the shielding plate may be formed by processing (e.g., photo-curing) a part of the phosphor 21.

In the configuration example of FIG. 3 in embodiment 1, the shielding plate has a height/thickness 301 that rises from the resist 60 on the plate 61 to the surface 21a of the phosphor 21 in the Z direction. In other words, the thickness of this shielding plate is the same as the thickness of the phosphor 21.

The advantage of the example configuration of the shielding plate in Figure 3 is that by ensuring the height/thickness 301, it is possible to clearly divide and limit the illumination area in front of the vehicle into multiple areas. However, in the case of this example configuration, when looking toward the headlight from the front, i.e., when viewing the illumination by the beam, the area where the shielding plate is located may be seen as a dark line, i.e., a part that appears relatively dark in the illumination.

[Modification: Shielding plate]
FIG. 4 similarly shows the configuration of a modified example of the shielding body of FIG. 3. FIG. 4 has shielding plates 81 and 82 as a difference from FIG. 3. The shielding plates 81 and 82 are formed to stand from the resist 60 on the plate 61 in the Z direction forward at a predetermined height 401, and from the surface 21a of the phosphor 21 to a position of a predetermined distance (in other words, a gap) 80 in front. That is, the shielding plates 81 and 82 are low-back shielding plates formed at a height 401 lower than the height 301 of the shielding plates 48 and 49 of FIG. 3. The height 401 of the shielding plates 81 and 82 of FIG. 4 and the distance 80 from the front end (highest position) to the surface 21a of the phosphor 21 are designed to appropriate values according to parameters such as the position and interval of the LED chips, the position and width of the shielding plates, and the resolution of the projection lens 1. That is, the values of the height 401 and the distance 80 are designed to be values that can sufficiently ensure the limit of the range of divergence of the light emitted from the LED chips.

For example, in FIG. 4, obliquely emitted light 83 and emitted light 85 (similar to emitted light 74 and emitted light 77 in FIG. 3) from the LED chip 27 is not blocked by the shielding plate 82 and exits from the surface 21a of the phosphor 21 through the gap 80 on the shielding plate 82. Similarly, obliquely emitted light 85 and emitted light 86 from the LED chip 27 is not blocked by the shielding plate 82 and exits from the surface 21a of the phosphor 21 through the gap 80 on the shielding plate 82.

Compared to the configuration example of FIG. 3, the configuration example of FIG. 4 has a weaker restriction on the dispersion of light emitted from the LED chip by the shielding plate, which increases the degree of dispersion of light emitted from the LED chip, resulting in a wider individual illumination area. The advantage of the configuration example of the shielding plate of FIG. 4 is that since the shielding plate is not exposed from the phosphor 21, when looking toward the headlight from the front, the area of the shielding plate is less visible as a dark line in the illumination.

Another possible variation of the shielding plate is a configuration in which a part of the shielding plate (the highest part) is exposed from the surface 21a of the phosphor 21 to a position a predetermined distance forward.

[Projection lens]
5 shows a cross-sectional view of the projection lens 1 in the XZ plane as a configuration of the projection lens 1 in the first embodiment. The projection lens 1 has optical characteristics for realizing a predetermined beam projection performance of the headlight in the first embodiment. Specifically, the projection lens 1 in the first embodiment has at least a resolution specification. As a specific example, this resolution (MTF) is 3 lp/mm (unit: line pairs per millimeter). The resolution of this projection lens 1 needs only to realize a resolution of 16% or more for light emitted forward (in the Z direction) from the patterning LED substrate 2 (in other words, emitted light).

The projection lens 1 in FIG. 5, in detail, has a convex lens 91, which is a first lens arranged in the Z direction on the side where light emitted from the aforementioned multiple LED chips on the main surface of the patterned LED substrate 2 enters as incident light, and a concave lens 90, which is a second lens arranged on the exit side of the convex lens 91. These two lenses are made of, for example, polycarbonate. Both the convex lens 91 and the concave lens 90 have aspheric shapes on the entrance surface and exit surface. This aspheric shape is a shape that allows the projection lens 1 to perform corrections such as aberration correction, i.e., corrections to form a suitable beam in front of the vehicle.

The shape and resolution specifications of this projection lens 1 are optimally designed to project light emitted from the characteristic patterned LED board 2 described above forward of the vehicle. By placing such a projection lens 1 at a predetermined distance in front of the patterned LED board 2 described above and using them in combination, a suitable illumination area can be formed by the headlight of embodiment 1.

[Patterning LED Substrate and LED Driving Circuit]
As described above, in the headlight of the first embodiment, unlike a simple LED array (comparative example of FIG. 16), the multiple LED chips of the patterned LED substrate 2 are arranged at predetermined positions corresponding to the illumination area in front of the vehicle (particularly, multiple areas designed to configure various light distribution patterns). Also, in the headlight of the first embodiment, multiple shielding plates are arranged at predetermined positions and with predetermined shapes corresponding to the illumination area in front of the vehicle.

Furthermore, in the headlight of embodiment 1, the multiple LED chips on the patterned LED substrate 2 are not designed to emit the same amount of light, but rather are designed so that each LED chip emits a different amount of light in accordance with the illumination area in front of the vehicle. The headlight is designed so that the amount of light emitted by each LED chip can be changed by the LED drive circuit 4 according to the light distribution pattern. This aspect will be described below.

[LED driving circuit]
FIG. 6 shows the configuration of the LED drive circuit 4 and the like. FIG. 6 mainly shows an example of the internal functional block configuration of the LED drive circuit 4 electrically connected to a vehicle controller 102 (e.g., an electronic control unit: ECU) of a vehicle equipped with the headlight of the first embodiment through wiring and a terminal 108. The LED drive circuit 4 is also connected to an on-board power supply 100 of the vehicle through a terminal 107. The on-board power supply 100 is connected to a ground 101. The LED drive circuit 4 is also electrically connected to a plurality of LEDs (LED chips 22 to 42) of the patterned LED substrate 2 through terminals 109, 110, 111, etc. on the LED drive circuit 4 side, wiring, and terminals 104, 105, 106, etc. on the patterned LED substrate 2 side. The plurality of LEDs are connected to the ground 101 through a terminal 103.

The LED drive circuit 4 includes a microcontroller 126, a regulator 125, a switch 124, a boost converter 128, a reference voltage circuit 127, and a number of LED PWM drive units 112, 113, and 114. Each LED PWM drive unit is a drive circuit associated with a specific LED chip.

The LED PWM drive unit includes terminals 115, 116, 117, 109, a comparator (differential amplifier) 133, a step-down control circuit 129, a switch (ON/OFF switch) 130, a current detection circuit 131, a current-voltage conversion circuit 132, etc.

The microcontroller 126 includes circuits such as a processor and memory. Alternatively, a memory or an external storage device that is external to the microcontroller 126 may be used. The memory stores setting information for controlling the drive of the multiple LED chips on the patterning LED board 2, for example in the form of table data.

This setting information is information for selecting a beam light distribution control pattern (also referred to as a light distribution pattern) that corresponds, for example, one-to-one to the mode indicated by the input information, based on a command from the vehicle controller 102 (or another part) or various vehicle information. In other words, the table of this setting information specifies, for example, the correspondence between the mode and the pattern. The details of this setting information are not limited.

The above modes are descriptive terms, but they represent the current conditions of the vehicle and its surroundings, or the lighting state that the vehicle controller 102 wants to achieve for the lighting in front of the vehicle. The modes represent, for example, which areas are to be brightened and which areas are to be darkened using ADB light distribution control or the like, such as a mode that turns off the lights in front of the oncoming lane to protect against fenders, a mode that lights up the area ahead of the right turn to warn drivers when turning right, and a mode that lights up white lines in rainy weather.

The above modes are associated, for example, one-to-one with specific light distribution patterns. The light distribution pattern is a pattern that specifies which specific areas in the lighting area in front of the vehicle are to be illuminated brightly and which specific areas are to be illuminated darkly, and specifies which LED chips are to be turned on or off and the amount of light each LED chip is to emit. The microcontroller 126 selects and determines the light distribution pattern at that time based on the setting information in the memory in accordance with input information (e.g., mode specification) from the vehicle controller 102.

Although the mode and the light distribution pattern are separate, they may be defined as the same thing, and the same effect can be obtained. If they are defined as the same thing, the light distribution pattern is specified from the vehicle controller 102 to the microcontroller 126.

Below are examples of information (referred to as vehicle information) that the vehicle controller 102 can grasp regarding the vehicle surroundings, etc. Based on such vehicle information, the vehicle controller 102 can determine what mode the headlights should be in.

Examples of vehicle information include speed information, gear information, steering wheel angle information, lamp illumination information, external light information, distance information, infrared information, engine ON/OFF information, camera image information (inside and outside the vehicle), acceleration gyro information, GPS information (including current time), navigation information, vehicle-to-vehicle communication information, and road-to-vehicle communication information.

Alternatively, the headlight microcontroller 126 may determine the mode or light distribution pattern based on acquired vehicle information.

In the setting information of the microcontroller 126, each mode and each light distribution pattern is identified, for example, by an ID. For each light distribution pattern, it is possible to specify whether the LED chip at each position should be turned on or off and the amount of light. The LED chip at each position is also identified by an ID (LED chip ID).

As described below, the number of LED devices in series constituting the LED chip (22-42) may differ for each LED chip at each position on the patterning LED board 2. To accommodate such a configuration, the setting information for the light distribution pattern of the microcontroller 126 also includes control information on how to perform the step-down control (described below) in each LED PWM driver so that the light intensity of the LED chip at each position can be variably specified within a predetermined range.

In FIG. 6, a power supply voltage is supplied from the vehicle power supply 100 to the LED drive circuit 4 through the terminal 107. This power supply voltage is supplied to the microcontroller 126 through the regulator 125, and in the supply state, the microcontroller 126 automatically starts up. The power supply voltage is supplied to the boost converter 128 through the on state of the switch 124, and the boost converter 128 boosts the power supply voltage to generate a common power supply voltage for the multiple LED chips and the LED PWM drive units. The common power supply voltage is supplied to each LED PWM drive unit (particularly the step-down control circuit 129) through the terminal 117, etc.

The reference voltage circuit 127 also supplies a reference voltage to each LED PWM driver (particularly the comparator 133) via terminal 116, etc.

When the microcontroller 126 controls the headlights to have a certain light distribution pattern, it transmits a drive control signal corresponding to that light distribution pattern to each LED PWM driver via terminal 115, etc.

The LED PWM driver is a circuit portion that drives the associated LED chip with a pulse width modulated (PWM) current (in other words, an LED drive current). For example, the LED PWM driver 112 outputs an LED drive current from terminal 109 by controlling the drive of the internal circuit according to a drive control signal input through terminal 115. The LED drive current is supplied to the LED chip 22 through terminal 104, and one or more LED devices constituting the LED chip 22 (in the case of the LED chip 22, one LED device 701 as shown in FIG. 7A) are driven, causing the LED chip 22 to emit light.

In each LED PWM drive unit, a switch 130 (for example, composed of a MOS switch) is turned ON/OFF by a drive control signal. In addition, a comparator 133 receives the drive control signal as a control input, a reference voltage as a positive input, and a detection voltage after IV conversion from the LED drive current as a negative input, and outputs a difference voltage.

The step-down control circuit 129 inputs the common power supply voltage and the differential voltage. The step-down control circuit 129 outputs a voltage (also referred to as a step-down voltage) that is the common power supply voltage stepped down according to the differential voltage. When the switch 130 is in the ON state, the step-down voltage is output from an output terminal (terminal 109, etc.) via the current detection circuit 131.

The LED drive current output from the LED PWM drive unit (terminal 109, etc.) is a current signal (in other words, a PWM signal) that includes PWM on and off periods in response to the switching control of switch 130 between the on and off states. Each LED chip is switched on and off according to the LED drive current. As a result, the amount of light emitted from the LED chip is basically determined according to the length of the PWM on period. The amount of light emitted from the LED chip is also determined according to the configuration of the number of series of LED devices described below (Figure 7).

The processor of the microcontroller 126 executes processing according to the program read into the memory while appropriately using resources such as memory. This realizes a predetermined function, processing unit, etc. The processor is composed of a semiconductor device such as a CPU. The processing is not limited to software program processing, but can also be implemented by a dedicated circuit. The dedicated circuit can be an FPGA, an ASIC, a CPLD, etc. The program may be installed as data in advance, or distributed as data from a program source. The program source may be a server on a communication network, or a non-transient computer-readable storage medium (e.g., a memory card). Various data and information are composed of structures such as tables, for example, but are not limited to this. Expressions such as identification information, identifiers, IDs, names, and numbers are mutually interchangeable.

[LED chip]
7 shows an example of the configuration of one or more LED devices in an LED chip. FIG. 7A shows a case where a certain LED chip, for example, the LED chip 22 near the left end of FIG. 2, is configured with one LED device 701. The number of series of this LED chip is 1. FIG. 7B shows a case where a certain LED chip, for example, the LED chip 25 in the left white line area of FIG. 2, is configured with three LED devices 701 connected in series. The number of series of this LED chip is 3. FIG. 7C shows a case where a certain LED chip, for example, the LED chip 31 in FIG. 2, is configured with four LED devices 701 connected in series. The number of series of this LED chip is 4. Each LED chip has a basic light emission amount according to the number of series, and the larger the number of series, the larger the basic light emission amount.

When one LED chip is composed of multiple LED devices 701 as in (B) and (C), an example of implementation is a configuration in which multiple LED devices 701 are connected in series in a direction (Z direction) perpendicular to the direction constituting the main surface (X-Y surface) of the patterned LED substrate 2 as shown in Figure 2. As long as a predetermined amount of light emission can be ensured for each LED chip when viewed in plan on the main surface, the configuration is not limited to such a vertical series connection configuration.

The number of LED devices 701 (corresponding number of series) as described above is designed according to the position of the multiple (for example, a total of 21 in FIG. 2) LED chips (22-42) on the main surface of the patterned LED board 2. As described above, multiple LED chips and multiple shielding plates are arranged on the main surface of the patterned LED board 2 in FIG. 2 in correspondence with the configuration of the illumination area in front of the vehicle (the configuration of multiple light distribution patterns described below). The basic light emission amount of the LED chips at each position is designed in correspondence with the configuration of the illumination area, and the number of series can differ for each position.

Specifically, in the first embodiment, in order to ensure the amount of illumination in the center of the illumination area in front of the vehicle, the multiple LED chips on the patterned LED substrate 2 are designed to have different numbers of series so that the basic light emission amount of the LED chip is greater in the center than in the peripheral area. The center refers to a portion such as the area 1608 in the comparative example of FIG. 16, and in FIG. 2, it corresponds particularly to the vicinity of the positions of the LED chips 35 and 31 on the second line 2C. The LED chips 35 and 31, and certain LED chips in the vicinity thereof, such as the LED chips 36 and 37 and the LED chip 34, are designed as LED chips with the largest number of series, for example, the configuration of (C) in FIG. 7. The LED chips located farther away from the LED chip 35 are designed as LED chips with a smaller number of series. For example, the LED chips 25 and 27 in the white line area are configured with a number of series of 3, as in (B) in FIG. 7. For example, the LED chips 22 and 30 near the left and right ends are configured as at least one LED device 701, as shown in FIG. 7A. The configuration of the LED devices in the multiple LED chips of the patterned LED substrate 2 is not limited to the above example.

Furthermore, the LED drive circuit 4 in FIG. 6 can control each LED chip, which may have a different basic light emission amount corresponding to the number of series as described above, as a variable light amount according to the light distribution pattern by PWM control. The LED drive circuit 4 in FIG. 6 is equipped with a step-down control circuit 129 for this purpose. The step-down control circuit 129 of each LED drive circuit 4 generates a step-down voltage by stepping down the common power supply voltage according to the basic light emission amount (corresponding number of series) of each corresponding LED chip. The common power supply voltage is designed to match the LED chip with the largest number of series. Step-down is not necessary for the LED chip with the largest number of series.

The LED drive circuit 4 controls the ON/OFF of the switch 130 based on the step-down voltage and a drive control signal corresponding to the light distribution pattern, thereby generating a PWM LED drive current. With this LED drive current, the actual amount of light emitted relative to the basic amount of light emitted can be variably determined according to the ratio of the lengths of the PWM on and off periods.

With this configuration, for example, in the center of Figure 2, near LED chip 35 and LED chip 26, a high basic amount of emitted light is ensured, and it is also possible to reduce the amount of emitted light below the basic amount in each area divided by the shielding plate according to the light distribution pattern at that time, for example to prevent glare.

[Lighting area]
FIG. 8 shows an outline of the configuration of the lighting area according to the law. FIG. 8 shows the lighting area in the case of low beam for passing on the right side of the road. The line h-h indicates the horizontal line and horizontal plane. The line v-v indicates the vertical line and vertical plane corresponding to the optical axis of the headlight. In the case of left-hand traffic, the lighting area is configured in a reversed left-right manner with respect to the line v-v in this figure. In this low beam lighting area, zone II 802 and zone IV 804 are turned on (high luminance) and zone III 803 is turned off (low luminance), thereby preventing dazzling of oncoming vehicles. The diagonal line 805 on the boundary between zone II 802 and zone III 803 is called the cutoff line. For example, the luminance [cd] required at point BR in zone II 802 is set to a maximum of 1750 cd. The luminance required at point B50L in zone III 803 is set to a maximum of 350 cd. The luminance range, etc. are also stipulated for the requirements of high beam.

[Light distribution pattern]
The following describes specific examples of patterns of beam distribution control associated with the modes in the headlight of embodiment 1. As described above, the arrangement of the multiple LED chips and the multiple shielding plates on the main surface of the patterned LED substrate 2 (in other words, the patterning) is designed to have predetermined positions, shapes, and dimensions in accordance with the configuration of the illumination area in front of the vehicle.

[First pattern]
Fig. 9 shows the configuration of the first pattern corresponding to the mode during normal low beam driving as a light distribution pattern. In Fig. 9 and other figures, the configuration of the main surface (X-Y surface) of the patterning LED substrate 2 is shown as seen from back to front in the Z direction, as in Fig. 2, so that the configuration of the illumination area toward the front of the vehicle is superimposed as it is for easy understanding. When the main surface of the patterning LED substrate 2 is seen from front to back in the Z direction, the configuration of Fig. 9 and other figures may be considered as being reversed from left to right.

In the first pattern in FIG. 9, regions 901 and 902 enclosed by dashed lines are both lighting regions where the LED chips are lit. Region 901 includes LED chips 23-29 on the first line 2B excluding the left and right ends, and LED chips 32 and 33 on the second line 2C. Region 902 includes LED chip 34 and LED chip 31 on the second line 2C. The portion on the second line 2C from the central LED chip 35 to the right LED chip 42 is turned off. The combined region of regions 901 and 902 constitutes an illumination region corresponding to the low beam as shown in FIG. 8. In particular, a cut-off line is also formed in region 902 by the shielding plate 51.

[Second pattern]
10 shows the configuration of the second pattern corresponding to the normal high beam driving mode. In the second pattern, areas 1001 and 1002 are the illumination areas. Area 1001 includes LED chips 23-29 on the first line 2B excluding the left and right ends. Area 1002 includes LED chips 32-42 and LED chip 31 on the second line 2C. Areas 1001 and 1002 form an illumination area corresponding to high beam. Area 1002 on the upper side in the Y direction corresponds to the front of the vehicle's lane when driving, and requires high luminous intensity.

[Third pattern]
11 shows the configuration of the third pattern corresponding to the high beam and ADB driving mode. The third pattern is a light distribution pattern in which ADB light distribution control is applied to the high beam. The headlight of the first embodiment is capable of selectively using not only the normal high beam (FIG. 10) to which ADB is not applied, but also the high beam to which such ADB is applied. The configuration of the LED chips and shielding plate of the patterned LED substrate 2 is designed to be compatible with the selective control of such a plurality of light distribution patterns.

The third pattern in FIG. 11 has areas 1100, 1101, 1102, and 1103. In the third pattern, areas 1100, 1101, and 1102 are lit areas, and area 1103 is an unlit area (illustrated by a dot pattern). Area 1100 is an area on the first line 2B similar to that described above. Areas 1101, 1102, and 1103 are examples of dividing an area including LED chips 32-42 on the second line 2C into three areas. Area 1101 is an area including LED chips 32-34, LED chip 31, and LED chips 35-37 from the left. Area 1102 is an area including LED chips 38 and 39. Area 1103 is an area including LED chips 40, 41, and 42. Areas 1101 and 1102 are particularly divided by shielding plate 54. Areas 1102 and 1103 are particularly separated by the shielding plate 56.

When considered in terms of the illumination area, area 1103 corresponds to the area in front of the vehicle's own lane to the right. In a situation where, for example, there is an oncoming vehicle (other vehicle) in this area, one mode is to perform ADB light distribution control such that the area is not illuminated or is dimmed to prevent dazzle. The third pattern corresponds to such a mode.

As shown in the figure, the area on the second line 2C on the upper side in the Y direction has a configuration in which multiple LED chips are divided by multiple shielding plates, so that it is possible to separate it into, for example, three areas 1101, 1102, and 1103 in the third pattern by control. Then, by turning off or dimming the LED chips associated with a specified area, for example area 1102, a high beam can be achieved using ADB.

In the third pattern above, a certain area 1102 is set as an off area, but as can be easily understood from the drawing, if the area divided by the shielding plate is used as a constituent unit and the other constituted areas are set as off or dimmed, it is similarly possible to realize an ADB with other contents by changing the target area and direction.

When applying each light distribution pattern, if there is a variably controllable parameter within that pattern (for example, an area to be targeted for glare prevention in ADB), the parameter value may be specified from the vehicle controller 102 along with the mode, etc. Alternatively, the microcontroller 126 may automatically control the parameter value.

[Fourth pattern]
12 shows the configuration of the fourth pattern corresponding to the driving mode of high beam and variable light distribution width control. The fourth pattern is a light distribution pattern in which variable light distribution width control is applied to high beam. The variable light distribution width control here refers to variably controlling the width (horizontal direction, width in the X direction) of the area illuminated as high beam by using multiple areas divided by LED chips and shielding plates, for example, for the area on the upper second line 2C. The lower area 1200 is the same lighting area as described above.

In this example, the area on the upper second line 2C has five areas, from the left, namely areas 1201, 1202, 1203, 1204, and 1205. Area 1201 is an area that includes LED chips 32 and 33. Area 1202 is an area that includes LED chip 34. Area 1203 is an area that includes LED chips 31, 35, and 36. Area 1204 is an area that includes LED chips 37 and 38. Area 1205 is an area that includes LED chips 39 to 42.

In the fourth pattern, the variable light distribution width control determines the width of the high beam area according to the vehicle speed, for example. For example, at low speeds, it is preferable for the high beam area to be wider, and at high speeds, it is preferable for the center (front) to be brighter than the width of the high beam area. In the variable light distribution width control, the width of the high beam area may change on the time axis according to changes in vehicle speed.

For example, in a certain variable light distribution width control corresponding to low speed, all five regions from region 1201 to region 1205 are set as lighted regions. That is, the width of the high beam at this time is the width corresponding to the region on the second line 2C including region 1201 to region 1205. Also, at this time, for example, in region 1203 corresponding to the center, the luminous intensity may be relatively smaller than in other control. Also, in another variable light distribution width control, for example, three regions from region 1202 to region 1204 are set as lighted regions, and region 1201 and region 1205 are set as extinguished regions. That is, the width of the high beam at this time is the width corresponding to the region from region 1202 to region 1204. Also, at this time, for example, in region 1203 corresponding to the center, the luminous intensity may be relatively larger than in other control, for example, maximum.

[Fifth pattern]
FIG. 13 shows the configuration of the fifth pattern corresponding to the driving mode of high beam and variable light distribution center control. The fifth pattern is a light distribution pattern in which variable light distribution center control is applied to high beam. The variable light distribution center control here refers to variably controlling the area (also described as light distribution center area) that has the largest amount of light (corresponding luminous intensity) among the areas illuminated by the light distribution control. In other words, this variable light distribution center control is to provide areas with relatively large and small amounts of light within the illumination area. In this example, the variable light distribution center control specifically includes the following two types of control.

The first light distribution center variable control controls a specified portion of the high beam area (the area on the second line 2C) to have the highest light intensity at a certain point in time. For example, when the vehicle is curved to the right, it is preferable for the high beam from the headlights to illuminate a direction and area to the right of the center. In response to this, this control basically lights up the area on the second line 2C during high beam, and sets the light intensity of a specified portion of that area to be the highest. In other words, when the specified area is set to a first light intensity, the other area is set to a second light intensity that is smaller than the first light intensity. This makes it possible to achieve high beams that are suitable for curved right driving.

In the example of FIG. 13, the area on the upper second line 2C has, for example, six areas, from the left, areas 1301, 1302, 1303, 1304, 1305, and 1306. Area 1301 is an area that includes LED chips 32 and 33. Area 1302 is an area that includes LED chip 34. Area 1303 is an area that includes LED chips 31, 35, and 36. Area 1304 is an area that includes LED chips 37 and 38. Area 1305 is an area that includes LED chips 39 and 40. Area 1306 is an area that includes LED chips 41 and 42.

At a certain point in time, for example, in response to driving around a right curve, area 1301 is set as an off area, and the other areas 1302 to 1306 are set as on areas. That is, in response to driving around a right curve, a high beam area is formed as an area to the right of the center. Furthermore, within the right area (five areas), a specified portion of the area, for example the central area 1304 (shown in a dashed-dotted frame) of the five, is set as an on area with the greatest amount of light. The amount of light emitted by the LED chip can be controlled by the aforementioned PWM control, for example. This makes it possible to achieve high beams that are suitable for driving around a right curve.

Furthermore, the second light distribution center variable control is added with control on the time axis. Although only the first control is sufficient, adding the second control can realize a more suitable high beam. In this second control, the area in the high beam area where the light amount is the highest is moved on the time axis. For example, the area where the light amount is the highest is determined according to the vehicle speed. For example, when driving on a right curve at a low speed, it is preferable to make the area of the upper high beam area where the light amount is the highest relatively closer to the right than when driving on a high speed curve. When driving on a right curve at a high speed, it is preferable to make the area of the high beam area where the light amount is the highest closer to the center. In this way, in the second control, for example, when driving on a right curve, the area of the high beam area where the light amount is the highest moves left and right on the time axis according to the change in vehicle speed.

As an example of the second control, when driving around a right curve at low speed, of the areas 1302 to 1306 that are turned on, for example area 1306 or area 1305 is set to be the area with the greatest amount of light. When driving at high speed, of the areas 1302 to 1306 that are turned on, for example area 1304 is set to be the area with the greatest amount of light.

[Sixth pattern]
FIG. 14 shows a sixth pattern corresponding to a mode during cornering. Cornering is turning right or left. The sixth pattern is a light distribution pattern for cornering that is different from high beam and low beam. The sixth pattern is a light distribution pattern that, for example, illuminates an area near the right end of the lighting area with respect to the center when turning right, and illuminates an area near the left end of the lighting area with respect to the center when turning left. For example, if such lighting is used when turning right, it is possible to pay attention to the area to turn right.

The sixth pattern has areas 1401 and 1402 on the first line 2B, which are the lit areas. Area 1401 is an area near the left end of the area on the first line 2B, and area 1402 is an area near the right end of the area on the first line 2B. Area 1401 includes the LED chip 22 on the left end, and is shielded by shielding plates 43 and 44. Area 1402 includes the LED chip 30 on the right end, and is shielded by shielding plates 45 and 46.

These shielding plates are formed to extend in an oblique direction as described above. For example, shielding plate 43 extends diagonally downward to the right from the upper left corner toward LED chip 23, with a gap between it and LED chip 23. There is an opening between the end of shielding plate 43 and the end of shielding plate 44. When LED chip 22 is turned on, it is shielded by shielding plates 43 and 44, and light emission spreads to the right from the opening, so that region 1401 has a shape that spreads up to the vicinity of LED chip 23.

Conventional vehicles use cornering lamps separate from headlights when cornering. In contrast, the headlights of the first embodiment can provide illumination in the sixth pattern when cornering, and this headlight alone can provide a beam when cornering similar to that of a cornering lamp.

As shown in the figure, the sixth pattern uses a diagonal shielding plate to form diagonal areas 1401, 1402 that extend outward to the left and right. The human eye generally has an eye-catching effect. Taking this into consideration, the diagonal areas 1401, 1402 shown in the figure are designed. This makes it easier for people to recognize the beam when cornering.

[Seventh Pattern]
FIG. 15 shows a seventh pattern corresponding to a mode for improving white line recognition (in other words, white line emphasis) in rainy weather, etc. The white lines here are the left and right white lines constituting the vehicle's lane on the road. In rainy weather, etc., the white lines may be difficult to see. The seventh pattern is a light distribution pattern that emphasizes the white lines so that they are easily recognized by the human eye, in addition to high beams and low beams. The seventh pattern has areas 1501 and 1502 on the first line 2B, which are considered as light-on areas. The area 1501 includes the LED chip 25 one chip left from the center, and is an area that is shielded by the shielding plates 47 and 48. The area 1502 includes the LED chip 27 one chip right from the center, and is an area that is shielded by the shielding plates 49 and 50. The area 1501 is designed with a position, shape, size, etc. that correspond to the white line on the left side of the vehicle's lane. The area 1502 is designed with a position, shape, size, etc. that correspond to the white line on the right side of the vehicle's lane.

Shielding plates 47 and 48 are formed to extend diagonally upward to the right from the bottom left toward the center on second line 2C, and both ends are open. Shielding plates 49 and 50 are formed to extend diagonally upward to the left from the bottom right toward the center on second line 2C, and both ends are open. When LED chip 25 is lit, it is shielded by shielding plates 47 and 48, and light emission spreads from the open parts. As a result, area 1501 is a diagonal band-shaped area that corresponds to the white line on the left side.

By using the seventh lighting pattern in rainy weather, the white lines will be more visible, allowing for safer driving.

[Multiple Patterns]
The above-mentioned patterns may be combined for application. For example, when it is desired to apply high beam, ADB, and white line recognition depending on the vehicle driving conditions and mode, the third pattern and the seventh pattern may be combined.

The headlight of the first embodiment has a common configuration so that multiple patterns such as those in the above example can be selected and executed. As part of this configuration, the multiple LED chips and multiple shielding plates of the patterned LED substrate 2, the LED drive circuit 4, etc. are designed.

The multiple patterns may correspond to multiple modes required by a certain vehicle manufacturer. Furthermore, if multiple vehicle manufacturers each require different modes, it is also possible to have multiple patterns that correspond to all of the multiple modes required by those multiple vehicle manufacturers. In this case, one headlight can be compatible with multiple vehicle manufacturers.

[Projection lens]
The projection lens of the first embodiment is a projection lens constituting the headlight of the first embodiment as described above, and is an optical element that is disposed in front of the patterning LED board 2, like the projection lens 1 in Fig. 1, and projects a suitable beam forward with a predetermined resolution based on forward light emission (emitted light) from the patterning LED board 2 to form an illumination area in front of the vehicle. In addition, this projection lens is not limited to vehicle headlights and the patterning LED board 2, and can be similarly applied to other illumination devices and light source devices.

[Headlight control method]
The headlight control method of the first embodiment is a method for controlling the headlight of the first embodiment as described above, and in particular, a method for controlling the headlight with a light distribution pattern according to the mode of the vehicle to form a suitable illumination area in front of the vehicle. This headlight control method includes a step of the LED drive circuit 4 (particularly the microcontroller 126) selecting and determining a light distribution pattern according to vehicle information or mode designation, etc., based on the configuration of Fig. 6 etc., a step of driving and controlling a plurality of LED PWM drive units in accordance with the light distribution pattern, and a step of supplying an electric signal (LED drive current) by PWM control from the plurality of LED PWM drive units to the plurality of LED chips of the patterned LED substrate 2 to cause the plurality of LED chips to emit light while controlling the on/off and light emission amount of the plurality of LED chips.

[Effects, etc.]
As described above, the headlight etc. of embodiment 1 differs from the conventional bi-function type or the type using an array/matrix type optical element in that it can be configured with a small number of mechanical parts and optical elements, thereby making it possible to realize a suitable headlight etc. that can reduce costs, improve reliability, and ensure the amount of light in the center of the illumination area.

Although the embodiments of the present disclosure have been specifically described above, they are not limited to the above-described embodiments and can be modified in various ways without departing from the gist of the present disclosure. In each embodiment, components can be added, deleted, or replaced, with the exception of essential components. Unless otherwise specified, each component can be singular or plural.

The technology according to this embodiment can provide a headlight device that can ensure the amount of light in the center of the lighting area when the vehicle is traveling, ensure forward visibility by the lit lighting area, and contribute to supporting safe driving, thereby making it possible to prevent traffic accidents. This contributes to the achievement of "Good health and well-being for all," one of the Sustainable Development Goals (SDGs) advocated by the United Nations.

1...projection lens, 2...patterned LED substrate, 3...heat sink, 4...LED drive circuit, 21...phosphor, 22-42...LED chips, 43-58...shielding plates, 61...plate.

Claims (16)

An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips, the phosphor emitting yellow or red and green light using the purple to blue wavelength light as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
Each LED chip of the plurality of LED chips has one or more LED devices connected in series in a predetermined number of series according to the determined position;
The number of LED chips in series is larger in a central portion of the LED chips than in a peripheral portion of the LED chips in accordance with the configuration of the forward illumination region.
Headlight. 2. The headlight according to claim 1,
the LED substrate has a shielding plate disposed between predetermined LED chips of the plurality of LED chips so as to stand forward, the shielding plate shielding light emitted from the LED chips and limiting forward dispersion from the LED chips;
The shielding plate is disposed on the plate at a predetermined position and in a predetermined shape so as to realize the light distribution control of the plurality of patterns.
Headlight. 2. The headlight according to claim 1 ,
The LED driving circuit includes:
a step-down control circuit that generates step-down voltages corresponding to the respective LED chips from a common power supply voltage;
and a switch for PWM-controlling each of the LED chips in accordance with the selected pattern.
Headlight. 3. The headlight according to claim 2,
The shielding plate stands on the plate to the surface of the phosphor.
Headlight. 3. The headlight according to claim 2,
The shielding plate stands on the plate at a position a predetermined distance below the surface of the phosphor.
Headlight. An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips, the phosphor emitting yellow or red and green light using the purple to blue wavelength light as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
The LED drive circuit stores setting information for drive control of the plurality of LED chips corresponding to the plurality of light distribution control patterns in a memory.
Headlight. An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips and emitting yellow or red and green light using the light of a wavelength from purple to blue as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
the LED substrate has a shielding plate disposed between predetermined LED chips of the plurality of LED chips so as to stand forward, the shielding plate shielding light emitted from the LED chips and limiting forward dispersion from the LED chips;
the shielding plate is disposed on the plate at a predetermined position and in a predetermined shape so as to realize the light distribution control of the plurality of patterns;
The configuration of the forward illumination area includes white line areas on the left and right of the vehicle's lane,
the plurality of LED chips include LED chips arranged at positions corresponding to the white line areas,
One of the patterns is a pattern that brightens the area of the white line,
The shielding plate includes a shielding plate disposed at a position determined to divide the white line area, the shielding plate being disposed in an oblique direction within a main surface of the LED substrate.
Headlight. 3. The headlight according to claim 2,
the plurality of LED chips include LED chips arranged at positions corresponding to the low beam area in the forward illumination area,
The shielding plate is arranged at a position determined to divide the low beam region, and includes a shielding plate arranged in an oblique direction within the main surface of the LED substrate in correspondence with the cutoff line,
Headlight. 3. The headlight according to claim 2,
the plurality of LED chips include LED chips arranged at positions corresponding to the high beam area in the forward illumination area,
The shielding plate includes a shielding plate disposed at a predetermined position for further dividing the high beam region into a plurality of regions,
As one of the patterns, a pattern for controlling light distribution of the high beam and ADB is included,
The LED drive circuit drives and controls the high beam so that a part of the high beam area is turned off or dimmed when the high beam is in a high beam and ADB light distribution control pattern is in effect.
Headlight. An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips and emitting yellow or red and green light using the light of a wavelength from purple to blue as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
the LED substrate has a shielding plate disposed between predetermined LED chips of the plurality of LED chips so as to stand forward, the shielding plate shielding light emitted from the LED chips and limiting forward dispersion from the LED chips;
the shielding plate is disposed on the plate at a predetermined position and in a predetermined shape so as to realize the light distribution control of the plurality of patterns;
The configuration of the forward lighting area includes a cornering lighting area,
the plurality of LED chips include LED chips arranged at positions corresponding to an area of illumination during cornering,
The shielding plate includes a shielding plate disposed at a position determined to divide an illumination area during cornering, the shielding plate being disposed in an oblique direction within a main surface of the LED substrate,
One of the patterns includes a pattern for controlling light distribution during cornering,
The LED drive circuit controls driving so as to brighten the lighting area when the cornering is performed in a pattern in which light distribution control is performed when the cornering is performed.
Headlight. An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips and emitting yellow or red and green light using the light of a wavelength from purple to blue as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
the LED substrate has a shielding plate disposed between predetermined LED chips of the plurality of LED chips so as to stand forward, the shielding plate shielding light emitted from the LED chips and limiting forward dispersion from the LED chips;
the shielding plate is disposed on the plate at a predetermined position and in a predetermined shape so as to realize the light distribution control of the plurality of patterns;
the plurality of LED chips include a plurality of LED chips arranged at positions corresponding to the high beam region in the forward illumination region,
The shielding plate includes a shielding plate disposed at a predetermined position for further dividing the high beam region into a plurality of regions,
As one of the patterns, a pattern in which the high beam is used and the light distribution width is variable and controlled is included,
The LED drive circuit controls the high beam to change the light distribution width of the high beam area by turning on a selected part of the high beam area and turning off or dimming another selected part of the high beam area when the high beam is in a high beam and light distribution width variable control pattern.
Headlight. An LED substrate on which a plurality of LED chips are arranged;
an LED driving circuit that drives the LED chips on the LED substrate;
a projection lens disposed forward in a direction perpendicular to the LED board and configured to project light emitted from the LED board forward as a beam;
Equipped with
The LED substrate is
Plate and
The plurality of LED chips are disposed on the plate and emit light having wavelengths ranging from violet to blue;
a phosphor disposed on the plate to cover the plurality of LED chips and emitting yellow or red and green light using the light of a wavelength from purple to blue as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including a low beam and a high beam as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
the LED substrate has a shielding plate disposed between predetermined LED chips of the plurality of LED chips so as to stand forward, the shielding plate shielding light emitted from the LED chips and limiting forward dispersion from the LED chips;
the shielding plate is disposed on the plate at a predetermined position and in a predetermined shape so as to realize the light distribution control of the plurality of patterns;
the plurality of LED chips include a plurality of LED chips arranged at positions corresponding to the high beam region in the forward illumination region,
The shielding plate includes a shielding plate disposed at a predetermined position for further dividing the high beam region into a plurality of regions,
As one of the patterns, a pattern in which the high beam is used and the light distribution center is variable and controlled is included,
When the high beam is in a pattern in which the light distribution center is variable, the LED drive circuit controls the light distribution center of the high beam area to be changed by turning on a selected part of the high beam area and turning off or dimming another selected part of the high beam area.
Headlight. A projection lens constituting an illumination device,
The illumination device includes an LED board on which a plurality of LED chips are arranged, an LED drive circuit that drives the plurality of LED chips on the LED board, and the projection lens that is arranged forward in a direction perpendicular to the LED board and projects light emitted from the LED board forward as a beam,
the LED substrate includes a plate, the plurality of LED chips arranged on the plate and emitting blue light, and a phosphor arranged on the plate to cover the plurality of LED chips and emitting yellow light using the blue light as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control pattern selected from a plurality of light distribution control patterns as a light distribution control of a beam forward;
The LED drive circuit controls the on/off and light amount of each LED chip on the LED board, thereby realizing the light distribution control of the selected pattern;
The projection lens corrects the light emitted from the LED board for aberration and projects the light forward as a beam.
Projection lens. 14. The projection lens according to claim 13 ,
the projection lens includes a convex lens having an aspheric shape on an entrance surface and an exit surface, and a concave lens having an aspheric shape on an entrance surface and an exit surface, the concave lens being disposed on the exit side of the convex lens.
Projection lens. A headlight control method for controlling a headlight, comprising:
The headlight includes an LED board on which a plurality of LED chips are arranged, an LED drive circuit that drives the plurality of LED chips on the LED board, and a projection lens that is arranged forward in a direction perpendicular to the LED board and projects light emitted from the LED board forward as a beam,
the LED substrate includes a plate, the plurality of LED chips arranged on the plate and emitting blue light, and a phosphor arranged on the plate to cover the plurality of LED chips and emitting yellow light using the blue light as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including at least a low beam, a high beam, and an adaptive driving beam (ADB) as a light distribution control of a beam forward;
Each LED chip of the plurality of LED chips has one or more LED devices connected in series in a predetermined number of series according to the determined position;
The number of LED chips in series is larger in a center portion of the LED chips than in a peripheral portion of the LED chips in the center portion of the LED chips in the front illumination region.
The headlight control method includes:
The LED driving circuit selects the pattern corresponding to a lighting mode based on an instruction or vehicle information input according to a vehicle driving situation;
and a step of controlling, by the LED drive circuit, turning on and off and controlling the amount of light of each of the plurality of LED chips on the LED substrate for light distribution control of the selected pattern.
Headlight control method. A headlight control method for controlling a headlight, comprising:
The headlight includes an LED board on which a plurality of LED chips are arranged, an LED drive circuit that drives the plurality of LED chips on the LED board, and a projection lens that is arranged forward in a direction perpendicular to the LED board and projects light emitted from the LED board forward as a beam,
the LED substrate includes a plate, the plurality of LED chips arranged on the plate and emitting blue light, and a phosphor arranged on the plate to cover the plurality of LED chips and emitting yellow light using the blue light as an excitation light source;
each of the plurality of LED chips on the plate is disposed at a predetermined position corresponding to a configuration of a forward illumination area so as to realize a light distribution control of a pattern selected from a plurality of light distribution control patterns including at least a low beam, a high beam, and an adaptive driving beam (ADB) as a light distribution control of a beam forward;
the LED drive circuit stores, in a memory, setting information for drive control of the plurality of LED chips corresponding to the plurality of light distribution control patterns;
The headlight control method includes:
The LED driving circuit selects the pattern corresponding to a lighting mode based on an instruction or vehicle information input according to a vehicle driving situation;
and a step of controlling, by the LED drive circuit, turning on and off and controlling the amount of light of each of the plurality of LED chips on the LED substrate for light distribution control of the selected pattern.
Headlight control method.

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