JP5823211B2 - Vehicle headlamp device - Google Patents

Description

  The present invention relates to a vehicle headlamp device.

  2. Description of the Related Art Conventionally, an illumination device for a vehicle has been devised that includes a light source in which a plurality of semiconductor light emitting elements are arranged in a matrix and a condenser lens, and is configured to irradiate the front with a predetermined light distribution pattern ( For example, Patent Document 1).

JP 2001-266620 A

  However, if there is a gap between adjacent semiconductor light emitting elements, a dark portion between the semiconductor light emitting elements is projected, and a pattern may appear in the light distribution pattern, which gives the driver a feeling of strangeness.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for suppressing a sense of incongruity with a light source image.

  In order to solve the above-described problems, a vehicle headlamp device according to an aspect of the present invention includes a light source in which a plurality of semiconductor light emitting elements are arranged at intervals, and light emitted from the light source as a light source image in front of the vehicle. A projection lens for projection. The plurality of semiconductor light emitting elements are disposed in front of the focal point of the projection lens.

  According to this aspect, the dark part between the adjacent semiconductor light emitting elements does not stand out in the projected light source image.

  The semiconductor light emitting element may be arranged such that the light emitting surface faces the front of the vehicle. This eliminates the need for a reflecting member such as a reflector.

  The semiconductor light emitting element may be arranged such that the light emitting surface is rectangular and the side of the light emitting surface is inclined with respect to the vehicle width direction. Thereby, it becomes easy to form an oblique cut-off line. Also, the horizontal cut-off line can be blurred.

  The semiconductor light emitting element may be arranged such that the distance between the semiconductor light emitting element and the projection lens is 0.98 f or less, assuming that the focal length of the projection lens is f [mm]. This

  In the semiconductor light emitting device, the focal length of the projection lens is f [mm], one side of the light emitting surface of the semiconductor light emitting device is W [mm], and the pitch between the semiconductor light emitting device and the adjacent semiconductor light emitting device is P [mm]. ], The distance between the semiconductor light emitting element and the projection lens may be ((P−W) / P) × f or more.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, etc. are also effective as an aspect of the present invention.

  According to the present invention, a sense of incongruity with a light source image can be suppressed.

It is the figure which looked at the principal part of the headlight which arranged a plurality of semiconductor light emitting elements in matrix from the side. It is the figure which looked at the state which arranged a plurality of LED chips in matrix from the front. FIG. 3A shows an optical path when light emitted from the focal point enters the projection lens, and FIG. 3B shows an optical path when light emitted from the rear side of the focal point enters the projection lens. FIG. 3C is a diagram illustrating an optical path when light emitted from the front of the focal point enters the projection lens. It is a schematic diagram which shows the arrangement | sequence of the matrix LED which has arrange | positioned each side of a rectangular LED chip in parallel with a horizontal direction. It is the schematic block diagram which looked at the vehicle headlamp apparatus which concerns on this Embodiment from the side. FIG. 6 is a schematic diagram showing an arrangement of matrix LEDs when the light source shown in FIG. 5 is viewed from the front. FIG. 7A is a diagram showing a low beam light distribution pattern formed by the vehicle headlamp device according to the present embodiment, and FIG. 7B is a vehicle headlamp device according to the present embodiment. It is a figure which shows the high beam light distribution pattern formed by these. It is the figure which expanded a part of matrix LED which concerns on this Embodiment. Fig.9 (a) and FIG.9 (b) are the figures for demonstrating the modification of matrix LED which concerns on embodiment. FIG. 10A to FIG. 10C are diagrams showing spot beam-like light distribution patterns formed by matrix LEDs. It is a figure which shows an example of the light distribution pattern formed with the vehicle headlamp apparatus which concerns on this Embodiment. It is a block diagram which shows schematic structure of a headlight system. It is a flowchart which shows an example of the control in the headlight system which concerns on this Embodiment. FIG. 14A is a diagram showing the lighting state of the matrix LED when forming the basic beam (BL), and FIG. 14B is an arrangement formed by the matrix LED in the lighting state shown in FIG. FIG. 14C is a diagram showing a light pattern, FIG. 14C is a diagram showing a lighting state of a matrix LED when forming a town beam (TL), and FIG. 14D is a lighting state matrix shown in FIG. 14C. The figure which shows the light distribution pattern formed by LED, FIG.14 (e) is a figure which shows the lighting state of matrix LED at the time of forming a motorway beam (ML), FIG.14 (f) is FIG.14 (e). FIG. 14G is a diagram showing a light distribution pattern formed by the matrix LED in the lighting state shown in FIG. 14B. FIG. 14G is a diagram showing the lighting state of the matrix LED when forming the wet beam (WL). 14 (h) is a diagram showing a light distribution pattern formed by the matrix LED in the lighting state shown in FIG. 14 (g), and FIG. 14 (i) is a diagram of the matrix LED when swiveling the motorway beam (ML). The figure which shows a lighting state, FIG.14 (j) is a figure which shows the light distribution pattern formed by matrix LED of the lighting state shown in FIG.14 (i).

  In recent years, development of devices using a plurality of semiconductor light emitting elements such as LEDs as a light source of a headlight unit (headlight) of a vehicle or the like has been progressing. FIG. 1 is a side view of a main part of a headlight in which a plurality of semiconductor light emitting elements are arranged in a matrix. In FIG. 1, a plurality of LED chips 212 are arranged on a plane including the focal point F of the projection lens 210 and perpendicular to the optical axis L. Here, H is the principal point of the projection lens, f is the focal length, and fb is the back focus.

  FIG. 2 is a front view of a plurality of LED chips arranged in a matrix. An optical system in which a light source composed of a plurality of LED chips (hereinafter referred to as “matrix LEDs”) arranged in a matrix in this way is directed to the front of the vehicle and a projection lens is arranged in front of the light source. The luminance distribution of the chip is projected forward. Therefore, if there are a plurality of LED chips, the luminance distribution of the LED chip group is projected on the screen. However, headlamps using such matrix LEDs have room for improvement in the following respects.

  (1) Dark portions between LED chips (corresponding to the gaps g1 and g2 shown in FIG. 2) are conspicuous on the screen. Such a dark part partially reduces the visibility of the driver. For example, when there is a partition in front of the road, a rectangular pattern appears there. Moreover, a striped pattern may appear on the road surface.

  (2) It is difficult to form an oblique (45 degrees) cutoff offline Z light distribution necessary for the low beam light distribution pattern. In addition, the vicinity of the cut-off line is not blurred.

  Next, image formation by the projection lens will be described. FIG. 3A shows an optical path when light emitted from the focal point enters the projection lens, and FIG. 3B shows an optical path when light emitted from the rear side of the focal point enters the projection lens. FIG. 3C is a diagram illustrating an optical path when light emitted from the front of the focal point enters the projection lens.

  As shown in FIG. 3A, when a light source (object) is placed on the focal point F, the image is formed at infinity. The actual focal length of the projection lens is about 30 to 50 mm. Compared with this focal length, the distance to the imaging screen (10 m or 25 m) can be said to be infinite. Therefore, the luminance distribution of the light source is projected as it is on the screen, and the dark part between the LED chips is conspicuous.

  As shown in FIG. 3B, when the light source is installed on the rear side of the focal point F, the dark part between the LED chips is still conspicuous because the image of the light source is a real image with a magnification of b / a.

  On the other hand, as shown in FIG. 3C, when a light source is installed in front of the focal point F, the image of the light source becomes a virtual image and does not form on the screen. If the light source is too close to the projection lens, it does not function as a projection lens and it is difficult to form a desired light distribution.

  As a result of intensive studies based on such knowledge, the present inventor has made it possible to make the luminance unevenness of the matrix LED inconspicuous by arranging the LED chip in front of the focus and in the vicinity of the focus as much as possible. It came to the point that it is preferable to make an image into a virtual image. Also, the inventors have conceived that the virtual image magnification should be as large as possible. Therefore, the magnification of the virtual image is obtained as follows.

As shown in FIG. 3C, when the distance between the object (light source) and the projection lens is a and the focal length is f, the imaging position (imaging distance b) is an imaging formula of a paraxial optical system. It is represented by a certain formula (1).
1 / f = 1 / a-1 / b (1)

  Table 1 shows the imaging distance b and magnification b / a of the virtual image when the distance a is f / 2, 2f / 3, 3f / 4, 4f / 5, 9f / 10, and 19f / 20. .

  As shown in FIG. 3C, the light emitted from the light source proceeds as if it is emitted from the virtual image position. Therefore, as the luminance distribution on the screen is higher, a plurality of semiconductor light emitting elements (LED chips) are overlapped, and the unevenness on the screen becomes inconspicuous.

  Next, a description will be given of a point where it is difficult to form an oblique cutoff line necessary for the above-described low beam light distribution pattern and a point where the vicinity of the cutoff line is not blurred. FIG. 4 is a schematic diagram showing an array of matrix LEDs in which each side of a rectangular LED chip is arranged in parallel with the horizontal direction.

  In the case of the matrix LED shown in FIG. 4, even if the LED chip in the region R1 surrounded by the dotted line is turned on and the other LED chips are turned off, a Z light distribution having a 45-degree oblique cutoff line cannot be formed. In order to realize the Z light distribution with the LED chip arrangement as shown in FIG. 4, it is necessary to further increase the number of LED chips and form an oblique cut-off line in a pseudo manner. However, in such a case, since the size of the matrix LED increases, it is necessary to increase the focal length of the projection lens, resulting in an increase in lamp size. Therefore, the inventor diligently studied these problems and came up with the idea of adopting a matrix LED having a layout described later.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  FIG. 5 is a schematic configuration diagram of the vehicle headlamp device according to the present embodiment as viewed from the side. The vehicle headlamp device 10 includes a light source 14 in which LED chips 12 that are a plurality of semiconductor light emitting elements are arranged at intervals, a projection lens 16 that projects light emitted from the light source 14 as a light source image in front of the vehicle, and . The light source 14 includes an LED circuit board 18 and a heat sink 20. The plurality of LED chips 12 are arranged in front of the focal point F of the projection lens 16.

  Therefore, in the vehicle headlamp device 10 according to the present embodiment, as described above, since the light source image is projected forward as a virtual image, the dark portion between the adjacent LED chips 12 is the projected light source. Disappears in the image. In addition, the some LED chip 12 is arrange | positioned so that the light emission surface may face the vehicle front. This eliminates the need for a reflecting member such as a reflector.

  FIG. 6 is a schematic diagram showing an arrangement of matrix LEDs when the light source shown in FIG. 5 is viewed from the front. In the matrix LED shown in FIG. 6, each LED chip is arranged so that each side of the LED chip having a rectangular light emitting surface is inclined (45 degrees to the horizontal) with respect to the horizontal direction (vehicle width direction). .

  In the case of such a matrix LED, when the LED chip in the region R2 surrounded by the dotted line is turned on and the other LED chips are turned off, the LED chips 12a to 12c that are lit are clearly inclined at 45 degrees. Offline is formed. Moreover, since the upper edge of the region R2 of the LED chip that is lit has a sawtooth shape, the horizontal cut-off line can be blurred.

  FIG. 7A is a diagram showing a low beam light distribution pattern formed by the vehicle headlamp device according to the present embodiment, and FIG. 7B is a vehicle headlamp device according to the present embodiment. It is a figure which shows the high beam light distribution pattern formed by these. By turning on the LED chips arranged in the region R2 among the matrix LEDs shown in FIG. 6, as shown in FIG. 7A, a low-beam light distribution pattern PL of Z light distribution is performed by a light source composed of matrix LEDs. Is formed. Further, by turning on all the matrix LEDs shown in FIG. 6, a high beam light distribution pattern PH shown in FIG. 7B is formed.

  Next, an appropriate virtual image magnification according to the size of the LED chip and the interval between the LED chips will be described. FIG. 8 is an enlarged view of a part of the matrix LED according to the present embodiment. In FIG. 8, W is the size of the LED chip, P is the pitch interval between adjacent LED chips, Ph is the pitch interval in the horizontal direction of the LED chip, and Pv is the pitch interval in the vertical direction of the LED chip.

  In this case, the magnification of the virtual image needs to be at least P / W times. For example, if the chip size W is 1 mm □ and the pitch is 3 mm, P / W = 3, and the imaging magnification by the projection lens must be at least 3 times. The object position (distance) for realizing this is 2f / 3 from Table 1.

  Therefore, it is necessary to install the LED chip between the position of 2/3 of the focal length f and the position of the focal point F from the projection lens. However, when an LED chip is placed on the focal point F, uneven brightness starts to appear on the screen.

  Therefore, in the LED chip, the focal length of the projection lens 16 is f [mm], one side of the light emitting surface of the LED chip is W [mm], and the pitch between one LED chip and another adjacent LED chip is P [ mm], the distance between the LED chip and the projection lens 16 is preferably ((P−W) / P) × f or more.

  In the case of P / W = 3, considering the LED chip installation error S, the LED chip position may be installed between 2f / 3 and f-S from the projection lens. In practice, the light source is preferably installed at a position where the magnification is larger than the actual P / W in consideration of mass productivity. Further, the installation error S may be set as appropriate in consideration of the standard deviation σ of manufacturing accuracy.

  As described above, the matrix LED may be installed in front of the focal position F of the projection lens (on the projection lens side). The matrix LED is installed at a position where the magnification of the virtual image by the projection lens is larger than P / W and smaller than 50 times (f = 50), where the LED chip size is W and the pitch (chip spacing) is P. In this case, the range of a = 49) is preferable.

  Specifically, the LED chip may be arranged so that the distance between the LED chip 12 and the projection lens 16 is 0.98 f or less, where f [mm] is the focal length of the projection lens 16. Thereby, the dark part between the chips of the matrix LED can be made inconspicuous. In the matrix LED, when the distance to adjacent LED chips is different in the vertical direction and the horizontal direction, the pitch interval P is set to be wider (P is larger).

  In the matrix LED, the horizontal pitch interval Ph of the LED chips may be greater than or equal to the vertical pitch interval Pv. Thereby, the Z light distribution shape can be further clarified. In addition, since the light flux density can be increased in the vertical direction, it is easy to form a horizontally long light distribution pattern suitable for a headlight.

  Thus, the vehicle headlamp device 10 according to the present embodiment is a projection type headlamp that employs a matrix LED as a light source, and is based on the presence state of the front vehicle from the front monitoring sensor. In addition to a general low beam light distribution pattern and high beam light distribution pattern, various light distribution patterns described later can be realized.

  Next, a modification of the variable light distribution headlamp system using the matrix LED will be described. Fig.9 (a) and FIG.9 (b) are the figures for demonstrating the modification of matrix LED which concerns on embodiment. FIG. 10A to FIG. 10C are diagrams showing spot beam-like light distribution patterns formed by matrix LEDs.

  As shown in FIGS. 9A and 9B, the matrix LED according to the modification uses about 4 to 10 LED chips. For example, the matrix LEDs are arranged as shown in FIG. 9A and are configured to form a spot beam-like light distribution pattern. In this case, the light distribution pattern P1 has a rectangular spot beam shape as shown in FIG. As shown in FIG. 10B, the light distribution pattern P1 may be moved in the horizontal direction along a curved path.

  Further, the matrix LED may be configured such that a part of the LED chips 12d is arranged in a rhombus arrangement as shown in FIG. 9B to form a spot beam-like light distribution pattern. In this case, it becomes easy to form a light beam distribution pattern P2 having a horizontally long elliptical spot beam shape as shown in FIG.

  FIG. 11 is a diagram illustrating an example of a light distribution pattern formed by the vehicle headlamp device according to the present embodiment. As shown in FIG. 11, the vehicle headlamp device 10 according to the present embodiment can form a light distribution pattern PH ′ that does not irradiate a partial region. Thereby, the visibility ahead of a vehicle is securable, without giving glare to a preceding vehicle.

(Control system configuration)
Next, the configuration of the headlight control system will be described. FIG. 12 is a block diagram showing a schematic configuration of the headlight system.

  The headlight system 100 includes left and right vehicle headlamp devices 10, a light distribution control ECU 102, a front monitoring ECU 104, and the like. As described above, the vehicle headlamp device 10 includes the light source 14 made of a matrix LED, the projection lens 16, and a lamp body that houses them. Each vehicle headlamp device 10 is connected to a drive device (ACT) 106 for swiveling the matrix LED and the lamp body.

  The forward monitoring ECU 104 is connected to various sensors such as an in-vehicle camera 108, a radar 110, and a vehicle speed sensor 112. The forward monitoring ECU 104 performs image processing on the imaging data acquired from the sensor, detects a forward vehicle (an oncoming vehicle or a preceding vehicle), other bright objects on the road, and lane markings (lane marks), and distributes their attributes and positions Data necessary for light control is calculated. The calculated data is transmitted to the light distribution control ECU 102 and various in-vehicle devices via an in-vehicle LAN.

  The light distribution control ECU 102 is connected to a vehicle speed sensor 112, a steering angle sensor 114, a GPS navigation 116, a headlamp switch 118, and the like. The light distribution control ECU 102 determines the traveling scene based on the attribute (oncoming vehicle, preceding vehicle, reflector, road lighting), the position (front, side), and the vehicle speed of the bright object sent from the front monitoring ECU 104. The light distribution pattern corresponding to is determined. Then, the light distribution control ECU 102 determines a control amount of the light distribution variable headlamp necessary for realizing the light distribution pattern. Here, the control amount is, for example, the vertical / left / right beam movement amount, the position and range of the masking portion (light-shielding region), and the like.

  In addition, the light distribution control ECU 102 determines the control contents (lights on / off, input power, etc.) of the driving device 106 and each LED chip of the matrix LED. The driving device 106 may be a mechanical driving device that drives the variable light distribution lamp unit in the vertical and horizontal directions. The driver 120 converts control amount information from the light distribution control ECU 102 into instructions corresponding to the operations of the driving device 106 and the light distribution control element and controls them.

(Control flowchart)
FIG. 13 is a flowchart showing an example of control in the headlight system according to the present embodiment.

  The process shown in FIG. 13 is repeatedly executed at predetermined intervals when selected by a headlamp switch or when a predetermined situation (night driving or driving in a tunnel) is recognized based on information from various sensors. The

  First, the light distribution control ECU 102 and the front monitoring ECU 104 acquire necessary data from a camera, various sensors, switches, and the like (S10). The data is, for example, data such as an image ahead of the vehicle, a vehicle speed, a distance between vehicles, a shape of a running road, a steering angle of a steering wheel, a light distribution pattern selected by a headlamp switch, and the like.

  The forward monitoring ECU 104 performs data processing 1 based on the acquired data (S12). By data processing 1, attributes of bright objects in front of the vehicle (signal lights, illumination lights, delineators, etc.), vehicle attributes (oncoming vehicles, preceding vehicles), distance between vehicles, brightness of bright objects, road shape (lane width, straight road) , Curve) and the like are calculated.

  Next, the light distribution control ECU 102 performs data processing 2 based on the data calculated in the data processing 1 (S14), and selects an appropriate light distribution pattern. The selected control light distribution pattern is, for example, a low beam light distribution pattern, a high beam light distribution pattern, ADB (Adaptive Driving Beam), or the like. Further, the LED chip is turned on and off, and the control amount of input power is determined according to the selected light distribution pattern.

  If ADB is selected (Yes in S16), data processing 3 is performed by the light distribution control ECU 102 (S18). In the data processing 3, for example, an illumination area and a light shielding area by the ADB control, an illumination light amount, and an irradiation direction are determined. In addition to these pieces of information, AFS (Adaptive Front-Lighting System) control is also possible based on the data calculated in the data processing 1. AFS control is to control light distribution according to a curved road, a traveling area (city area, suburb, highway), and weather. If ADB is not selected (No in S16), step S18 is skipped.

  Next, the light distribution control ECU 102 converts data for the driver in the data processing 4 (S20), and drives the light distribution control element and the actuator (ACT) (S22), thereby performing ADB control and swivel control.

(Various light distribution patterns)
FIG. 14A is a diagram showing the lighting state of the matrix LED when forming the basic beam (BL), and FIG. 14B is an arrangement formed by the matrix LED in the lighting state shown in FIG. FIG. 14C is a diagram showing a light pattern, FIG. 14C is a diagram showing a lighting state of a matrix LED when forming a town beam (TL), and FIG. 14D is a lighting state matrix shown in FIG. 14C. The figure which shows the light distribution pattern formed by LED, FIG.14 (e) is a figure which shows the lighting state of matrix LED at the time of forming a motorway beam (ML), FIG.14 (f) is FIG.14 (e). FIG. 14G is a diagram showing a light distribution pattern formed by the matrix LED in the lighting state shown in FIG. 14B. FIG. 14G is a diagram showing the lighting state of the matrix LED when forming the wet beam (WL). 14 (h) is a diagram showing a light distribution pattern formed by the matrix LED in the lighting state shown in FIG. 14 (g), and FIG. 14 (i) is a diagram of the matrix LED when swiveling the motorway beam (ML). The figure which shows a lighting state, FIG.14 (j) is a figure which shows the light distribution pattern formed by matrix LED of the lighting state shown in FIG.14 (i).

  The light distribution pattern shown in FIG. 14B is a current light distribution pattern like a low beam, and is used when passing an oncoming vehicle on a suburban road. Moreover, the light distribution pattern shown in FIG.14 (d) is used on the city road where road illumination exists. This light distribution pattern has a lower lighting performance than the current low beam due to the presence of road lighting. At the same time, the beam has a low glare quantity.

  The light distribution pattern shown in FIG. 14 (f) is used when traveling on an expressway with an antiglare fence. The current low beam cut-off line is shifted upward and the central luminous intensity is increased. The light distribution pattern shown in FIG. 14 (h) is used in rainy weather. This light distribution pattern reduces the amount of light in the front road surface region R4 in order to suppress glare given to the oncoming vehicle. That is, in the light distribution pattern of the motorway beam shown in FIG. 14 (f), the amount of light at the portion corresponding to the front road surface is reduced.

  The light distribution pattern shown in FIG. 14J can improve the visibility in the traveling direction as AFS control when the vehicle front is a curved road.

  In the description of the various light distribution patterns described above, only the lighting part of the matrix LED is shown. However, in actual application, the lighting current of the part may be adjusted as appropriate.

  The present invention has been described above with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention also relates to a combination or replacement of the configuration of the embodiment as appropriate. Is included. In addition, it is possible to appropriately change the combination and processing order in the embodiment based on the knowledge of those skilled in the art and to add various modifications such as various design changes to the embodiment. The described embodiments can also be included in the scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Headlamp apparatus for vehicles, 12 LED chip, 14 Light source, 16 Projection lens, 100 Headlight system, 102 Light distribution control ECU, 104 Front monitoring ECU.

Claims (5)

A light source in which a plurality of semiconductor light emitting elements are arranged at intervals, and
A projection lens that projects the light emitted from the light source as a light source image in front of the vehicle,
The plurality of semiconductor light emitting elements are:
Arranged in a matrix,
It is arranged in front of the focal point of the projection lens ,
The semiconductor light emitting element is
The light emitting surface is rectangular, and the side of the light emitting surface is arranged to be oblique to the vehicle width direction,
When the focal length of the projection lens is f [mm], the distance between the semiconductor light emitting element and the projection lens is 0.98f or less.
A vehicle headlamp apparatus characterized by the above.   The vehicle headlamp device according to claim 1, wherein the semiconductor light emitting element is disposed such that a light emitting surface thereof faces the front of the vehicle. In the semiconductor light emitting device, the focal length of the projection lens is f [mm], one side of the light emitting surface of the semiconductor light emitting device is W [mm], and the pitch between the semiconductor light emitting device and the adjacent semiconductor light emitting device is P. When [mm], according to claim 1 or 2, characterized in that it is arranged so that the distance between the projection lens and the semiconductor light emitting element is ((P-W) / P ) × f or more Vehicle headlamp device.   The vehicle headlamp device according to any one of claims 1 to 3, wherein the light source is disposed so as to intersect with an optical axis.   The vehicle light source according to any one of claims 1 to 4, wherein the light source is configured to selectively form either a low beam light distribution pattern or a high beam light distribution pattern. Lighting device.

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