JP6921622B2 - Lighting device - Google Patents

Description

The present invention relates to a lighting device used for a vehicle lamp or the like.

In recent years, a lighting device that reflects the light of a laser diode with a tiltable mirror unit, scans it, and then irradiates a phosphor panel to project a light distribution pattern has become widespread and is used for headlights for vehicles and the like. There is.

For example, the vehicle headlight of Patent Document 1 is composed of a fixed light distribution unit provided adjacent to each other and a variable light distribution unit. The fixed light distribution unit forms a common portion (for example, a road surface irradiation portion below the horizon when switching between low beam and high beam) in a plurality of light distribution patterns formed by vehicle headlights.

On the other hand, the variable light distribution unit forms a portion that changes in a plurality of light distribution patterns formed by the vehicle headlights, that is, a portion of each light distribution pattern other than the pattern common portion formed by the fixed light distribution unit. .. The variable light distribution unit includes a light source module consisting of two laser devices, a MEMS (Micro Electro Mechanical Systems) mirror, a phosphor panel, etc., and a projection lens. The light emitted from the light source module is emitted by the projection lens to the vehicle. It is configured to be projected forward (paragraphs 0016 to 0018, FIG. 1).

Japanese Patent No. 5577138

However, as in Patent Document 1, when there are two optical systems of a fixed light distribution unit and a variable light distribution unit, there is a problem that it is difficult to superimpose each light distribution pattern according to the projection distance.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lighting device capable of efficiently generating a light distribution pattern.

The lighting device of the present invention includes a first light source, a first optical system for generating a fixed light distribution pattern, a second light source, a lens unit into which light from the second light source is incident, and the lens unit. The second optical system for generating a variable light distribution pattern, and the light from the first optical system and the second optical system are composed of a rotating mirror portion that reflects the light passing through the above in a predetermined angle range. A composite light distribution that combines the fixed light distribution pattern and the variable light distribution pattern by condensing the light emitted from the wavelength conversion unit and the wavelength conversion unit that emits light of different wavelengths when incident. It is characterized by including a projection lens for projecting a pattern.

In the lighting device of the present invention, a fixed light distribution pattern is generated in the first optical system, and a variable light distribution pattern is generated by the rotating mirror portion in the second optical system. The light of the first optical system and the light of the second optical system (for example, blue light) are incident on the wavelength conversion unit, respectively, and one image is formed on the wavelength conversion unit. Further, the wavelength of the light is changed by the wavelength conversion unit (for example, white light), and the composite light distribution pattern is projected by the projection lens.

After the light for each light distribution pattern is applied to the wavelength conversion unit, the composite light distribution pattern is projected on one optical axis of one unit, so that the light distribution patterns overlap even if the projection distance changes. The synthetic light distribution pattern can be efficiently generated without changing the condition.

According to this configuration, in the first optical system, the light from the first light source is reflected by the elliptic curved reflector. Further, since the first light source and the light-shielding portion are arranged at the focal position inside the reflector, the light reflected by the reflector is collected by the light-shielding portion, and a part of the light is shielded to the wavelength conversion unit. Incident in. At this time, since the light-shielding portion forms a boundary line between the fixed light distribution pattern and the variable light distribution pattern, a clear light distribution pattern can be generated.

Further, in the lighting device of the present invention, the first optical system includes a collimating lens that converts light from the first light source into parallel light, and a condensing lens that collects light that has passed through the collimating lens. It is preferable to further prepare.

According to this configuration, the light from the first light source is converted into parallel light (including substantially parallel light) by the collimated lens, then condensed by the condenser lens and irradiated to the wavelength conversion unit. As a result, the light emitted from the first light source, which is the source of the fixed light distribution pattern, is surely irradiated to a predetermined position of the wavelength conversion unit.

Further, in the lighting device of the present invention, it is preferable that the projection lens is composed of a plurality of lenses, and the variable light distribution pattern is projected on the projected screen above the fixed light distribution pattern.

According to this configuration, by combining a plurality of lenses as projection lenses, it is possible to suppress aberrations, enlarge an image, and invert the final composite light distribution pattern. Also, the variable light distribution pattern is projected on the screen above the fixed light distribution pattern. As a result, when the lighting device is used as a light distribution variable headlamp (ADB: Adaptive Driving Beam), the variable light distribution pattern can be moved or masked according to the position of an oncoming vehicle or the like.

Further, in the lighting device of the present invention, the light from the first light source and the light from the second light source are partially overlapped on the wavelength conversion unit to form the variable light distribution pattern and the fixed light distribution pattern. It is preferable to generate a synthetic light distribution pattern in which a part of the light is partially overlapped.

According to this configuration, the fixed light distribution pattern always appears at the same position on the screen, and the variable light distribution pattern can change its position and shape. By partially superimposing the light from the first light source and the light from the second light source on the wavelength conversion unit, the variable light distribution pattern and the fixed light distribution pattern can be superposed. By superimposing both light distribution patterns to form a composite light distribution pattern, a bright region (hot zone) can be generated in the projection region.

Further, in the lighting device of the present invention, it is preferable that the first light source is composed of at least two or more light emitting diodes, and the second light source is a laser diode having the same wavelength as the first light source.

According to this configuration, by using a light emitting diode as the first light source, it is possible to obtain a cheaper lighting device in which all the light sources are composed of laser diodes. Further, by using at least two or more light emitting diodes side by side, the fixed light distribution pattern can be a wide-angle light distribution.

Further, by making the wavelengths of the light of the light emitting diode of the first light source and the light of the laser diode of the second light source equal to each other, it is possible to suppress the color unevenness of the image between the fixed light distribution pattern and the variable light distribution pattern. Note that the equal wavelength means, for example, that all light sources are blue light (wavelength is about 450 nm), and does not mean that they are equal with an accuracy of 1 nm.

Further, in the lighting device of the present invention, the lens portion of the second light source is preferably a collimated lens that converts incident light into parallel light.

According to this configuration, the light from the second light source is converted into parallel light (including substantially parallel light) by the collimated lens, and then incident on the rotating mirror portion. As a result, the light emitted from the second light source, which is the source of the variable light distribution pattern, is surely incident on the rotating mirror unit, reflected, and irradiated to a predetermined position of the wavelength conversion unit.

The figure which shows the whole structure of the lighting apparatus of embodiment. The figure which shows the state that the light from a 1st optical system and the light from a 2nd optical system were incident on a phosphor plate. A block diagram showing a control configuration of a lighting device. Example of synthetic light distribution pattern (passage zone: left). Example of synthetic light distribution pattern (passage zone: right). Example of synthetic light distribution pattern (with hot zone). The figure (1) which shows the modification of the 1st optical system. The figure (2) which shows the modification of the 1st optical system.

FIG. 1 is a diagram showing an overall configuration of a lighting device 1 according to an embodiment of the present invention.

As shown in FIG. 1, the lighting device 1 includes a first optical system A including a light source 10a, a reflector 20, a shade 30, and a lens 40, and a second optical system B including a light source 10b, a lens 60, and a light deflector 70. , A phosphor plate 80, and a projection lens 90.

The first optical system A is a projection type optical system, and generates a fixed light distribution pattern (horizontal pattern) described later.

The light source 10a (corresponding to the "first light source" of the present invention) is composed of three parallel light emitting diodes (LEDs: Light Emitting Diodes), and in FIG. 1, the light emitting diodes are arranged in parallel in the direction toward the back of the paper. Has been done. A laser diode (LD) may be used as a light source, but the cost of the device can be reduced by reducing the number of laser diodes.

It is preferable to use at least two light emitting diodes in parallel. As a result, the finally generated fixed light distribution pattern can be a wide-angle light distribution. The center wavelength of the light emitting diode is about 450 nm, and blue light is output.

The light source 10a is arranged inside a reflector 20 (corresponding to the "reflecting mirror" of the present invention) whose inner surface is a reflecting portion. The reflector 20 has an elliptic curved surface, and an aluminum film is vapor-deposited on the inner surface thereof. More precisely, since the light source 10a is arranged at the focal position of the reflector 20, the light emitted from the light source 10a is reflected by the inner surface of the reflector 20 and converges to another focal position. The reflector does not have to be a perfect elliptic surface.

The shade 30 (corresponding to the "light-shielding portion" of the present invention) is a light-shielding plate that shields incident light and forms a boundary line at the upper end of a fixed light distribution pattern. An aluminum film is vapor-deposited on the surface of the shade 30 on which the light is incident. Further, the shade 30 is arranged at the focal position of the reflector 20 and at the rear focal point of the collimating lens 40a described later. A part of the light reflected by the inner surface of the reflector 20 and incident on the shade 30 is incident on the collimating lens 40a.

The lens 40 is composed of a collimating lens 40a and a condenser lens 40b. When the light reflected by the shade 30 is incident, the collimating lens 40a converts the light into parallel light and guides the light to the condenser lens 40b. Then, the light incident on the condenser lens 40b is condensed and irradiated on the phosphor plate 80.

Next, the second optical system B will be described. The second optical system B generates a variable light distribution pattern described later.

The light source 10b (corresponding to the "second light source" of the present invention) is composed of one laser diode (LD). The center wavelength of the laser diode is about 450 nm, and it is preferable to output blue light. This is to reduce the difference in image (color unevenness, etc.) from the fixed light distribution pattern generated by the light source 10a of the first optical system A.

The light emitted from the light source 10b is incident on the lens 60 (corresponding to the "lens portion" of the present invention). The lens 60 is a collimating lens, and when the light of the light source 10b is incident, the light is changed to substantially parallel parallel light and guided to the light deflector 70.

The light deflector 70 includes a MEMS mirror (corresponding to the “rotating mirror portion” of the present invention) that can be tilted two-dimensionally, and emits light emitted from the light source 10b and passes through the lens 60 to the phosphor plate 80. Reflect in the direction. The optical deflector 70 is arranged on the optical axis so that the light is incident on the central portion of the MEMS mirror at a fixed position.

As the optical deflector provided with such a MEMS mirror, for example, a mirror having a known configuration described in Japanese Patent Application Laid-Open No. 2005-128147 and Japanese Patent No. 4092283 can be applied.

Next, the phosphor plate 80 in which the light that has passed through the condenser lens 40b of the first optical system A and the light reflected by the MEMS mirror of the light deflector 70 of the second optical system B are incident will be described.

As the phosphor plate 80 (corresponding to the “wavelength conversion unit” of the present invention), a sapphire substrate coated with a phosphor with a constant film thickness was used. The phosphor is a fluorescent material that is excited by being irradiated with blue light emitted from the light sources 10a and 10b and emits yellow light having a complementary color relationship with the blue light. Therefore, white light, which is a mixture of blue light and yellow light, is emitted from this phosphor.

The phosphor plate 80 may have a curved surface shape. In this embodiment, _{a yellow phosphor of Y 3} Al ₅ O ₁₂ : Ce ³⁺ was used as the phosphor.

Next, the projection lens 90 into which the light emitted from the phosphor plate 80 is incident will be described. The projection lens 90 of the present embodiment is composed of four lenses 90a to 90d, and each lens has a role of suppressing distortion and improving the resolution of the light distribution pattern. The lens 90a closest to the phosphor plate 80 is arranged so that the rear focal point is at the position of the phosphor plate 80.

The projection lens 90 is not limited to the configuration of four lenses, and in particular, if the phosphor plate 80 has a curved surface shape, the light distribution pattern can be projected with a smaller number of lenses.

The projection lens 90 suppresses the aberration of the light from the phosphor plate 80, magnifies the image, and reverse-projects the image forward. In the light distribution pattern finally projected on the virtual screen S (corresponding to the "screen" of the present invention), a variable light distribution pattern is formed on the upper side of the fixed light distribution pattern (see FIG. 4). Therefore, as shown in FIG. 1, the first optical system A is arranged on the upper side of the second optical system B.

Since the light from the phosphor plate 80 has one optical axis when it enters the projection lens 90, the overlapping condition of each light distribution pattern does not change according to the projection distance, and a synthetic light distribution pattern is efficiently generated. can do. Further, since the lighting device 1 can generate a light distribution pattern in the entire area with one unit, the device can be miniaturized.

FIG. 2 shows a state of the phosphor plate 80 in a state where the light from the first optical system A and the light from the second optical system B are incident. Upper pattern P _A of the phosphor plate 80 _'is irradiated portion of the light from the first optical system A, the finally fixed light distribution pattern. The lower pattern P _{B 'is} of the phosphor plate 80, a radiation part of the light from the second optical system B, and the portion which becomes finally the variable light distribution pattern.

Incidentally, the boundary line L between the _'pattern P _{B as'} pattern P _A is made by the shade 30 of the first optical system A described above.

Next, FIG. 3 shows a block diagram of the control configuration of the lighting device 1.

As shown in FIG. 3, the lighting device 1 communicates with the front sensor 4 and the storage unit 5 in addition to the fixed light distribution unit 2 of the first optical system A and the variable light distribution unit 3 of the second optical system B. A unit 6 and a control unit 7 are provided.

The front sensor 4 senses the front of the vehicle to obtain peripheral information. The peripheral information referred to here is the existence of pedestrians, bicycles, oncoming vehicles, preceding vehicles, obstacles, etc., and the road surface condition. As such a front sensor 4, a known sensor such as a camera, a radar, or an acoustic sensor can be used.

The storage unit 5 stores map information including two-dimensional and three-dimensional geometric information about the road, in addition to position information such as traffic signals, external lighting, and road signs. In addition, the communication unit 6 obtains environmental information such as the position information of the own vehicle, the time, and the weather by communicating with the outside of the vehicle. The various information related to the storage unit 5 and the communication unit 6 may be obtained from a device provided in the vehicle.

The control unit 7 is connected to each of the above units and includes an arithmetic processing unit 7a and a drive control unit 7b. Of these, the arithmetic processing unit 7a receives various information from the front sensor 4, the storage unit 5, and the communication unit 6 to determine the optimum light distribution pattern to be formed. Then, the light distribution pattern information about the shape and the luminous intensity distribution of the light distribution pattern is output to the drive control unit 7b. At this time, various information from each unit is sequentially updated, and the determination of the light distribution pattern and the output of the light distribution pattern information are repeatedly performed at predetermined time intervals.

On the other hand, the drive control unit 7b controls the lighting of the light emitting diode (light source 10a) of the fixed light distribution unit 2. Further, the laser diode (light source 10b) and the MEMS mirror (light deflector 70) are controlled based on the light distribution pattern information input from the arithmetic processing unit 7a. Specifically, the drive control unit 7b controls the lighting intensity and lighting time of the laser light emitted from the laser diode, and also controls the tilt of the MEMS mirror.

Subsequently, the process of forming the light distribution pattern in the lighting device 1 will be described. First, as described above, when the arithmetic processing unit 7a determines the optimum light distribution pattern based on various information, the drive control unit 7b determines the laser diode and the MEMS mirror based on the light distribution pattern information for this light distribution pattern. To control. Drive control unit 7b is a fixed light distribution unit 2 is turned to form the horizontal pattern of the light distribution pattern (pattern P _{A 'of} FIG. 2) on the phosphor plate 80.

Further, the drive control unit 7b scans the light emitted from the laser diode and reflected by the MEMS mirror on the phosphor plate 80 with a predetermined scanning pattern corresponding to the pattern change portion to be formed.

The scanning mode may be a so-called vector scan in which the light is scanned so as to trace the shape of the pattern changing portion, or the light is scanned over the entire surface of the phosphor plate 80 including the portion outside the pattern changing portion. It may be a so-called raster scan. Alternatively, a combination of both formulas may be used. However, if you want to strongly irradiate only a specific part in the pattern change part, the vector scan is more efficient.

Next, the synthetic light distribution pattern formed on the virtual screen S will be described with reference to FIGS. 4A to 4C.

The composite light distribution pattern is a combination of a fixed light distribution pattern and a variable light distribution pattern, and when the lighting device 1 is used as a vehicle lamp, it is mainly used as a low beam light distribution. Hereinafter, an example in which the lighting device 1 is used as a vehicle lighting tool will be described.

First, FIG. 4A shows an example of a synthetic light distribution pattern when the traffic zone is on the left side. Below the virtual screen S, a fixed light distribution pattern P _A is projected, the variable light distribution pattern P _B are projected above the fixed light distribution pattern P _A. This is because the light emitted from the phosphor plate 80 is turned upside down by passing through the projection lens 90.

As shown in FIG. 4A, the variable light distribution pattern P _B is high on the left side, the height is switched at the center in the lateral direction, and the right side is low. This shape is called a Z beam or Z line, and is a typical light distribution pattern corresponding to the road regulations of each country.

The variable light distribution pattern P _B instantly and variously forms a mask portion that does not irradiate a part of the front of the vehicle by controlling the on / off of the light source 10b of the second optical system B and the MEMS mirror. be able to. For example, by masking the area where the pedestrian, the preceding vehicle or the oncoming vehicle exists detected by the front sensor 4, glare on the pedestrian, the preceding vehicle or the oncoming vehicle can be suppressed.

Next, FIG. 4B shows an example of a synthetic light distribution pattern when the traffic zone is on the right side. The point that the fixed light distribution pattern PA _A is irradiated below the virtual screen S and the variable light distribution pattern P _B is irradiated above is the same, but the variable light distribution pattern P _B is higher on the right side and higher at the center in the horizontal direction. Is switched, and the left side is low. Synthetic light distribution pattern shown in FIG. 4A, by changing only the variable light distribution pattern P _B, can be switched easily to the combined light distribution pattern shown in Figure 4B.

Next, FIG. 4C shows an example of a combined light distribution pattern of repeating a fixed light distribution pattern P _A and the variable light distribution pattern P _B. Here, the lower side near the center of the variable light distribution pattern P _B by the downwardly convex shape, and overlapped portion of the variable light distribution pattern P _B to a fixed light distribution pattern P _A.

The portion where the light distribution patterns overlap is a hot zone H in which the virtual screen S is irradiated with strong white light. By expanding or contracting the area of the hot zone H, it is possible to form a light distribution pattern according to the driving environment or a light distribution pattern according to the user's preference.

As described above, in the illumination device 1, the underlying image of the fixed light distribution pattern P _A by the first optical system A is created, the underlying image of the variable light distribution pattern P _B by the second optical system B is generated Will be done. These images are combined on the phosphor plate 80 to form one image, and the wavelength is converted and incident on the projection lens 90. Then, the image is enlarged by the projection lens 90, the top and bottom are inverted, and the composite light distribution pattern is projected on the virtual screen S.

Light emitted from the phosphor plate 80, because it is projected by an optical system having one optical axis, to prevent the fixed light distribution pattern P _A by the projection distance and the variable light distribution pattern P _B is deviated be able to.

Finally, a modified example of the lighting device 1 will be described with reference to FIGS. 5A and 5B.
The same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

First, FIG. 5A shows an example of a reflector type lighting device 100 composed of a first optical system A1 and a second optical system B. The first optical system A1 includes a light source 10a and a reflector 20, but does not have a collimating lens or a condenser lens. Therefore, although it is necessary to adjust the arrangement of the light source 10a and the reflector 20 and to enlarge the phosphor plate 80, it is possible to generate an image that is the source of the fixed light distribution pattern even with such a simple configuration. can.

Next, FIG. 5B shows an example of a direct projection type lighting device 120 composed of the first optical system A2 and the second optical system B. The first optical system A2 has a light source 10a and a lens 40, but does not have a reflector. Therefore, the light from the light source 10a passes through the collimating lens 40a and the condensing lens 40b in this order, and irradiates the phosphor plate 80.

Since both of the above lighting devices 100 and 120 have no shade, it is not possible to create a clear boundary line between the fixed light distribution pattern by the first optical systems A1 and A2 and the variable light distribution pattern by the second optical system B. However, a synthetic light distribution pattern can be generated with a small number of members.

As described above, the lighting devices 1, 100, 120 of the present embodiment can be mainly applied to vehicle headlights. Lighting devices 1, 100, 120 may be used for general lighting. Further, the above embodiment is an example, and various other modifications can be considered.

For example, the light source is not limited to blue light, but may be ultraviolet light or the like. It is necessary to change the type of phosphor in the phosphor plate according to the wavelength of the light of the light source so that white light is emitted.

Further, the above-mentioned phosphor plate 80 is a transmissive phosphor plate that emits light having a different wavelength from an exit surface on the opposite side of the incident surface when light is incident from the incident surface. However, the present invention is not limited to the transmissive type, and a reflective phosphor plate in which a reflective film is formed on the incident surface side and the reflected light is emitted from the same surface can also be used.

1,100,120 ... Illumination device, 10a ... Light source (first light source), 10b ... Light source (second light source), 20 ... Reflector (reflector), 30 ... Shade (light-shielding part), 40 ... Lens, 60 ... Lens (Lens unit), 70 ... Light deflector (rotating mirror unit), 80 ... Phosphor plate (wavelength conversion unit), 90 ... Projection lens.

Claims (6)

A first optical system equipped with a first light source for generating a fixed light distribution pattern,
In order to generate a variable light distribution pattern, it is composed of a second light source, a lens portion in which light from the second light source is incident, and a rotating mirror portion that reflects light that has passed through the lens portion in a predetermined angle range. 2nd optical system and
A wavelength conversion unit that emits light having a different wavelength when light from the first optical system and the second optical system is incident.
Condenses the light emitted from the wavelength converting part, Bei example and a projection lens for projecting the synthesized light distribution pattern synthesized with the fixed light distribution pattern and the variable light distribution pattern,
The first optical system shields an elliptical curved reflecting mirror that reflects light from the first light source and a part of the light reflected by the reflecting mirror, and the fixed light distribution is performed by the wavelength conversion unit. A light-shielding portion that forms a boundary line between the pattern and the variable light distribution pattern is further provided.
An illuminating device characterized in that the first light source and the light-shielding portion are arranged at a focal position inside the reflector. In the lighting device according to claim 1,
The first optical system further includes a collimating lens that converts light from the first light source into parallel light, and a condensing lens that collects light that has passed through the collimating lens. .. In the lighting device according to claim 1 or 2.
The projection lens is composed of a plurality of lenses.
The illuminating device, characterized in that the variable light distribution pattern is projected onto the projected screen above the fixed light distribution pattern. In the lighting device according to any one of claims 1 to 3.
A composite light distribution pattern in which the light from the first light source and the light from the second light source are partially overlapped on the wavelength conversion unit, and the variable light distribution pattern and a part of the fixed light distribution pattern are overlapped. A lighting device characterized by producing. In the lighting device according to any one of claims 1 to 4.
The first light source is composed of at least two or more light emitting diodes.
The second light source is a lighting device characterized by being a laser diode having the same wavelength as the first light source. In the lighting device according to any one of claims 1 to 5.
The lens unit of the second light source is a lighting device characterized by being a collimated lens that converts incident light into parallel light.

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