JP6703786B2 - Lighting equipment - Google Patents

Description

The present invention relates to an illuminating device including a light emitting unit having a phosphor that receives excitation light emitted from a light source unit and emits light.

BACKGROUND ART Conventionally, there is known a technique of irradiating a light emitting unit containing a phosphor with laser light to excite the phosphor to obtain a white light source. In addition, recently, a technique is known in which the emission shape of a white light source is arbitrarily changed by scanning the phosphor with laser light for exciting the phosphor.

As an example of application of this kind of technology, for example, in a headlight for an automobile, an external condition such as an oncoming vehicle, a pedestrian, a road sign, and a road surface is monitored by a camera, and an appropriate light emission is performed according to an external situation. In order to obtain a pattern, a white light source is made to emit light in a shape corresponding to a light projection pattern to be projected. Such a mechanism is referred to as a situation-adaptive headlight (Adaptive Driving Beam, hereinafter simply referred to as ADB) or the like.

Further, a technique is known in which a fluorescent substance is scanned using a plurality of excitation light sources, and various excitation light sources are controlled in synchronization with scanning to obtain various light distribution patterns.

For example, Patent Document 1 discloses a technique for obtaining a light distribution pattern suitable for a vehicle headlight by defining a scanning range of two scanning lights. In addition, Patent Document 2 discloses a method of overlapping a plurality of light emission patterns by using a plurality of excitation light sources and a plurality of MEMS (Micro Electro Mechanical Systems). Further, Patent Document 3 discloses a technique of scanning light emitted from two laser devices at different portions on a phosphor panel.

JP-A-2015-185476 (Published October 22, 2015) JP-A-2015-138735 (Published July 30, 2015) JP, 2015-38884, A (published on February 26, 2015)

However, in the related art as described above, details of how to control the light source unit have not been examined, and specific measures have been taken regarding how to improve the reliability of the light source unit. There is a problem that it does not exist.

The present invention has been made in view of the above problems, and an object thereof is to provide a lighting device that can improve the reliability of a light source unit by defining the lighting/non-lighting timing of the light source unit. It is to be realized.

In order to solve the above problems, an illumination device according to an aspect of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that includes a phosphor that emits light by receiving the excitation light, and the light emitting unit. An excitation light scanning unit that scans a spot of the excitation light that is incident on the light emitting unit, and a light projecting unit that projects light emitted from the light emitting unit into a desired light projecting shape. And each of the spots is derived from the excitation light of each of the plurality of light source units, causes the plurality of light source units to be turned on and off, and only one light source unit at the same time. A light source control unit for turning on, the light source control unit, in the light projection shape, when there is a dark portion that is not projected and a bright portion that is projected, the area of the dark portion is The larger the area, the higher the pulse peak value for driving the light source section .

In order to solve the above problems, the lighting device according to one aspect of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that emits light by receiving the excitation light emitted by the light source unit, and the light source unit. And a light source control unit for driving the light source control unit, wherein the light source control unit drives at least two of the plurality of light source units so as to emit excitation light at different timings.

In order to solve the above problems, the lighting device according to one aspect of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that emits light by receiving the excitation light emitted by the light source unit, and the light source unit. A driving light source control unit, and an excitation light scanning unit that controls an irradiation position of the excitation light with respect to the light emitting unit, wherein the light source control unit includes at least two of the plurality of light source units, respectively. The driving is characterized in that the excitation light is emitted at different timings.

In order to solve the above problems, the lighting device according to one aspect of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that emits light by receiving the excitation light emitted by the light source unit, and the light source unit. And a driving light source control unit, wherein at least two of the plurality of light source units respectively irradiate different positions of the light emitting unit with excitation light, and the light source control unit controls the at least two light source units. It is characterized by driving so as to emit the excitation light at different timings.

According to one aspect of the present invention, the effect of improving the reliability of the light source unit is provided by defining the lighting/non-lighting timing of the light source unit.

(A) is a figure which shows the schematic structure of the illuminating device which concerns on Embodiment 1 of this invention, (b) is scanning by the excitation light from the light source part 2A, and scanning by the excitation light from the light source part 2B. FIG. 4C is a diagram showing a state in which the two are overlapped with each other, FIG. 6C is a graph showing a change over time of the drive current of the light source unit 2A, and FIG. , (E) are graphs showing a state in which the graphs of (c) and (d) are superimposed. (A) is a figure which shows the schematic structure of the illuminating device of a comparative example, (b) is a graph which shows the time change of the drive current of 102 A of light source parts, (c) is the drive current of 102 B of light source parts. It is a graph which shows the time change of. It is a figure which shows an example of the arrangement|positioning method of a some polygon mirror. (A) is a figure which shows another example of the arrangement|positioning method of a some polygon mirror, (b) is a figure which shows the lighting/non-lighting pattern of each spot in scanning area A1 and A2. (A) is a graph which shows the time change of the drive current of 2 A of light source parts regarding the illuminating device which concerns on Embodiment 2 of this invention, (b) is a graph which shows the time change of the drive current of the light source part 2B. Yes, (c) is a graph showing a state in which the graphs of (a) and (b) are superimposed. (A) is a figure which shows the schematic structure of the illuminating device which concerns on Embodiment 3 of this invention, (b) shows the scanning by the excitation light from the light source part 2A, and the scanning by the excitation light from the light source part 2B. FIG. 4C is a diagram showing a state in which the two are overlapped with each other, FIG. 6C is a graph showing a change over time of the drive current of the light source unit 2A, and FIG. , (E) are graphs showing a state in which the graphs of (c) and (d) are superimposed. (A) is a figure which shows the schematic structure of an illuminating device which concerns on Embodiment 4 of this invention, and an example of a light emission part scanning pattern, (b) is a figure which shows another example of a light emission part scanning pattern, (C) is a figure which shows the example of the light distribution pattern corresponding to the light emission part scanning pattern shown to (a), (d) is an example of the light distribution pattern corresponding to the light emission part scanning pattern shown to (b). FIG. 6E is a graph showing the change over time of the drive current of the light source unit 2A corresponding to the light emitting unit scanning pattern shown in FIG. 7A, and FIG. 6F is the light emitting unit shown in FIG. It is a graph which shows the time change of the drive current of 2 A of light source parts corresponding to a scanning pattern. (A) is a figure which shows the schematic structure of an illuminating device concerning Embodiment 5 of this invention, and an example of a light emission part scanning pattern, (b) and (c) show another example of a light emission part scanning pattern. It is a figure, (d) is a graph which shows the time change of the drive current of 2 A of light source parts, (e) is a graph which shows the time change of the drive current of the light source part 2B. (A) is a graph which shows the time change of the drive current of the light source part 2A in another example of a light emission part scan pattern, (b) is a drive current of the light source part 2B in another example of a light emission part scan pattern. It is a graph which shows a time change, (c) is a graph which shows the state which overlapped each graph of (d) of FIG. 8 and (e) of FIG. 8, (d) is (a) and (a). It is a graph which shows the state which overlapped each graph of b). It is a figure which shows the schematic structure of the illuminating device of a modification. It is a graph which shows the relationship between time and a drive current in two light source parts.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 11. Hereinafter, for convenience of description, configurations having the same functions as the configurations described in the specific items will be denoted by the same reference numerals, and description thereof will be omitted.

[Embodiment 1]
FIG. 1A is a diagram showing a schematic configuration of a lighting device 1A according to the first embodiment of the present invention. As shown in the figure, the illumination device 1A includes light source units 2A and 2B, optical systems α3A and 3B, excitation light scanning units 4A and 4B, optical systems β5A and 5B, a light emitting unit 6, a light projecting unit 7, and a light distribution pattern. The changing unit 8 and the light source control unit 9 are provided.

(Light source section 2A, 2B)
Each of the light source units 2A and 2B has one laser element (excitation light source) 2c mounted on a heat dissipation base having fins. In the present embodiment, there is one laser element 2c for each light source of the light source units 2A and 2B, but the present invention is not limited to such a configuration, and each of the light source units 2A and 2B has a plurality of laser elements. 2c may be provided. Further, in the present embodiment, the form in which the light source unit is the two light source units 2A and 2B will be described, but the present invention is not limited to such a form, and the number of light source units may be three or more.

The laser element 2c is a light emitting element (LD: Laser Diode) including a chip that emits laser light, and functions as an excitation light source that excites the phosphor included in the light emitting unit 6. The laser element 2c may have one light emitting point on one chip or may have a plurality of light emitting points on one chip.

The peak wavelength of the laser beam emitted by the laser element 2c is selected from the blue-violet wavelength region of 380 nm or more and 415 nm or less, and is 395 nm, for example. However, the peak wavelength of the laser light of the laser element 2c is not limited to this, and may be appropriately selected depending on the application of the illumination device 1A or the type of phosphor included in the light emitting unit 6. For example, the laser element 2c may oscillate laser light in the so-called blue region having a peak wavelength in the wavelength range of 420 nm to 490 nm. For example, the laser element 2c oscillates laser light having a wavelength of 450 nm.

By using the laser light as the excitation light, it is possible to efficiently excite the phosphor contained in the light emitting unit 6 and increase the brightness, as compared with the case of using the light from the light emitting diode which is not the laser light. By increasing the brightness, the light emitting unit 6 can be downsized. Further, since the excitation light is laser light, the irradiation area (spot) of the excitation light in the light emitting section 6 can be narrowed. By efficiently narrowing the irradiation area, the resolution of the illumination pattern projected from the illumination device 1A can be increased. If this point is not taken into consideration, another light emitting element such as a light emitting diode can be used as the excitation light source instead of the laser element 2c.

Next, the heat dissipation base is a support member that supports the laser element 2c and also a heat dissipation member that dissipates heat generated from the laser element 2c. Therefore, the heat dissipation base is preferably made of a metal having strength and thermal conductivity so that heat can be efficiently dissipated, and is preferably made of, for example, aluminum or copper. The heat dissipation base may be made of a material containing a substance that is not a metal and has high thermal conductivity (for example, silicon carbide and aluminum nitride).

Further, the heat dissipation base is provided with fins to enhance heat dissipation efficiency. The fin is provided on the heat dissipation base on the side opposite to the side on which the laser element 2c is joined. The fin is a cooling mechanism, that is, a heat radiation mechanism that cools the heat transferred from the laser element 2c to the heat radiation base by heat radiation, and is composed of a plurality of heat radiation plates. Since the fins are composed of a plurality of heat dissipation plates, the contact area between the fins and the atmosphere increases, so that the heat dissipation efficiency of the fins can be improved.

(Optical system α3A, 3B)
The optical systems α3A and 3B are configured by an optical system that collimates laser light, a beam shaping optical system (lens, diffractive optical element, etc.) that shapes the spot shape of laser light, a condenser lens that condenses laser light, and the like. However, since it has little relation to the essence of the present invention, the description thereof is omitted here. The optical system α3A and the light source unit 2A may be optically connected via a light guide member such as an optical fiber. As the optical system α3A, for example, a bundle fiber (each laser light is guided by one optical fiber and the fibers are bundled) can be used. This makes it easy to store the beam in the excitation light scanning unit 4. This is because the emission points of the plurality of laser elements 2c are distant from each other, but with this method, they can be easily brought close to each other and are easily accommodated in the excitation light scanning unit 4.

(Excitation light scanning unit 4A, 4B)
The excitation light scanning units 4A and 4B adjust the incident position of the laser light on the light emitting unit 6 so that the spot of the laser light incident on the light emitting unit 6 is scanned on the light emitting unit 6. Further, there are a plurality of spots (in the present embodiment, spots 6a and 6b), and each of the spots 6a and 6b is derived from the excitation light emitted from the light emitting point of each of the light source units 2A and 2B. .. Further, in the excitation light scanning units 4A and 4B, the spots 6a and 6b, which are derived from the light source units 2A and 2B, respectively, which are lit or not lit, are arranged on the light emitting unit 6 at the same time and at the same position. The incident position of the laser light on the light emitting unit 6 is adjusted so that the laser light is scanned.

The excitation light scanning unit may be composed of a single mirror element. In this case, the configuration of the entire optical system becomes simple. Further, the excitation light scanning unit may be composed of the same number of mirror elements as the number of scanning excitation lights. According to the above configuration, the excitation light scanning unit can be configured by the mirror element capable of uniaxial scanning, and the degree of freedom of arrangement of each mirror element is increased. The excitation light scanning unit includes, for example, a mirror element (movable mirror) such as a galvanometer mirror, a polygon mirror, and a MEMS mirror, an acousto-optic element, or the like.

(Optical system β5A, 5B)
The optical systems β5A and 5B are optical systems that collimate the laser light, beam shaping optical systems that shape the spot shape of the laser light, focusing lenses that focus the laser light, and excitation light scanning units 4A and 4B according to the configurations of the excitation light scanning units 4A and 4B. Although the optical system is composed of an optical system (fθ lens or the like) for uniformizing the scanning of the light emitting section 6, it is not related to the essence of the present invention, and therefore its explanation is omitted here. The optical systems β5A and 5B can be omitted.

The excitation light scanning unit described above can be shared by a plurality of laser elements 2c (see FIG. 10).

(Light emitting part 6)
The light emitting section 6 includes a phosphor that receives the laser light emitted from the laser element 2c and emits fluorescence. Specifically, as the light emitting unit 6, a sealing type light emitting unit in which a phosphor is dispersed inside a sealing material, a crystal type light emitting unit in which the phosphor is hardened, or a substrate made of a material having high thermal conductivity. Examples thereof include a thin-film type light emitting unit in which phosphor particles are applied, that is, deposited. It can be said that the light emitting unit 6 is a wavelength conversion element for converting laser light into fluorescence.

Further, in the present embodiment, the shape of the light emitting unit 6 is, for example, a horizontally long rectangle having a length×width of 5 mm×15 mm, but the shape is not limited to this, and can be appropriately selected according to the application of the lighting device 1A and the like. is there. Further, in the present embodiment, the shape of the spot on the surface of the light emitting unit 6 on which the laser light is incident is shaped by the optical system so as to be substantially circular, but it is an ellipse that reflects the beam shape of the laser element. It may be. Further, the spot diameter is about 0.083 mm in the present embodiment, but the size can be appropriately changed depending on the design of the optical system.

In addition, in FIG. 1A, a plurality of spots adjacent to each other on the surface of the light emitting unit 6 on which the laser light is incident do not substantially have overlapping portions. Since a plurality of spots adjacent to each other do not overlap with each other, it is possible to reduce so-called brightness unevenness in which an overlapping portion is bright and a non-overlapping portion is dark. At this time, when not substantially overlapping, when the irradiation target is visually inspected, if the brightness unevenness cannot be confirmed, the peripheral portion of the spot may overlap with an adjacent spot, and the intended effect of the present invention can be obtained. Be done.

Note that, in FIG. 1A, the light emitting unit 6 corresponding to the light source unit 2A and the light emitting unit 6 corresponding to the light source unit 2B are expressed as separate light emitting units, but in reality, these light emitting units emit light. The parts are the same.

(Projector 7)
In front of the light emitting unit 6, a light projecting unit 7 such as a light projecting lens is provided. The light projecting section 7 projects the light emitted from the light emitting section 6 into a desired light projecting shape. The light projecting unit 7 can project the light emission pattern formed by scanning on the light emitting unit 6 forward and use it as illumination light. Further, for example, a desired light distribution pattern can be obtained by adjusting the lens shape of the light projecting lens.

Further, the direction of incidence of the excitation light on the light emitting unit 6 and the direction of taking out the light emitted from the light emitting unit 6 as illumination light may be the same or different. Generally, a form having the same direction is called a reflection type, and a form having different directions is called a transmission type. Although the light emitting unit 6 is stationary, it may be rotated to improve heat dissipation. However, in this case, it is necessary that the phosphor is uniformly formed.

(Light distribution pattern changing unit 8)
The light distribution pattern changing unit 8 controls the light source control unit 9 to perform control to change the light distribution pattern of the lighting device 1A into various patterns.

(Light source controller 9)
The light source control unit 9 causes each of the light source units 2A and 2B to perform a pulse operation in which lighting and non-lighting are repeated, and controls to light only one light source unit at the same time. More specifically, in the present embodiment, the light source control unit 9 determines that the scanning positions of the respective spots at the time of lighting (ON) or not lighting (OFF) are the same position on the light emitting unit 6, At the same time, only one light source unit is turned on, and the other light source units are all turned off. Note that the non-lighting (off) is not limited to the state where the current is 0 (zero) completely, and a weak current may be supplied within a range where the effect of the present application can be obtained.

Further, the light source control unit 9 may perform control to drive at least two of the plurality of light source units so as to emit the excitation light at different timings. As a result, none of the light source units are continuously turned on, and the reliability of the light source is improved.

Spot 6a derived from the light source unit 2A shown in FIG. 1 (a) is turned on at time _{t 1} (on), non-lighting at time _{t 2} (off), so that non-lighting at ... time _{t 8,} When the light emitting unit 6 is scanned from left to right with respect to the paper surface, lighting and non-lighting are alternately repeated. FIG. 1C is a graph showing the change over time of the drive current of the light source unit 2A.

On the other hand, the spot 6a derived from the light source unit 2B is unlit at time _{t 1} (off), the lighting at time _{t 2} (on), and so lit ... time _{t 8,} the top to the paper surface emitting part 6 On the other hand, when scanning from left to right, lighting and non-lighting are alternately repeated. FIG. 1D is a graph showing the change over time of the drive current of the light source unit 2B.

FIG. 1B is a diagram showing a state in which scanning with laser light from the light source unit 2A and scanning with laser light from the light source unit 2B are superimposed. As shown in the figure, in the state where the scanning with the laser light from the light source unit 2A and the scanning with the laser light from the light source unit 2B are superposed, it is as if a plurality of spots are lit at all times. Become. 1E is a graph showing a state in which the graphs of FIG. 1C and FIG. 1D are superimposed.

As described above, in the illumination device 1A, the light source control unit 9 performs control to turn on only one light source unit at the same time (either the laser element 2c of the light source unit 2A or the laser element 2c of the light source unit 2B). Control to light only one). As a result, none of the light source units are continuously turned on, so that the reliability of the light source unit is improved.

In other words, in the illuminating device 1A, when scanning the plurality of scanning lights on the light emitting section 6, the lighting/non-lighting timing is alternately set for each scanning light. As a result, even if the light distribution pattern is such that lighting continues, one light source unit does not continue to light, and the reliability of the light source improves. At this time, it is not necessary to turn on only one light source unit at exactly the same time. For example, even if there is a period in which the drive current is formed in a rectangular shape and the plurality of light source units are turned on, it is sufficient if the effect of the present application is substantially obtained. However, since such an overlap appears as uneven brightness in the light projection pattern, it is preferable that no overlap exists.

More specifically, as shown in FIG. 11, the drive current does not necessarily need to be in the ON state at exactly one of the light source units at exactly the same time. As long as the unevenness of brightness is not a problem for the illumination light, some overlap is allowed. As shown in the figure, if the timing is such that the peak time of the other (light source unit B) is not included in the period in which one (light source unit A) is on, the unevenness does not substantially pose a problem. The effect of the present application can be obtained.

That is, the light source control unit 9 may drive at least two light source units such that their respective light emission peaks are temporally different. Further, the light source control unit 9 may drive at least two light source units so that the portions where the respective light emission outputs are 75% or more of the peak value do not overlap.

As a result, none of the light source units are continuously turned on, and the reliability of the light source is improved.

Further, in the present embodiment, the scanning areas of the light emitting portions 6 of the plurality of spots 6a and 6b are common, and the plurality of spots 6a and 6b are scanned at the same position at the same time, The scanning positions of the spots when lit (or not lit) are different from each other. As a result, even if the light distribution pattern is such that the light emitting section 6 is continuously lit on the scanning line, no light source section is continuously lit, and the reliability of the light source section is improved.

Further, the light source control unit 9 has a plurality of output circuits (not shown) that each output a drive signal for driving one corresponding light source unit, and the drive signal is output based on the timing signal input to each output circuit. The timing signal may be controlled so that at least two output circuits among the output circuits generate the drive signals at different timings. As a result, none of the light source units are continuously turned on, and the reliability of the light source is improved.

(Significance of light source reliability)
Next, the significance of the reliability of the light source unit will be described. There are the following two degradation modes of the semiconductor laser (LD): (1) and (2).

(1) Sudden deterioration: A phenomenon in which sudden oscillation stop (light output becomes substantially zero) or extreme light output drop occurs due to some cause (generally considered to be end face damage, electrical connection breakdown, active layer breakdown, etc.) Is. Although the generation trigger has not been sufficiently clarified, it is considered that the generation risk can be reduced by shortening the lighting time without continuous lighting and lowering the average temperature (junction temperature) of the active layer.

(2) Deterioration with time: This is deterioration with time of the luminous efficiency of the LD. It is generally said that the average junction temperature during driving determines the deterioration rate, and the lower the junction temperature, the lower the deterioration rate.

The form of "not continuous lighting" and "the average junction temperature can be lowered depending on the pulse condition" of the present application is effective against any deterioration, that is, the reliability of the light source unit can be improved. In the case of an LED, the above-mentioned (1) sudden deterioration does not usually occur, but only the above-mentioned deterioration with time occurs.

[Regarding Lighting Device 101A of Comparative Example]
FIG. 2A is a diagram showing a schematic configuration of the illumination device 101A of the comparative example. In addition, FIG. 2B is a graph showing the change over time of the drive current of the light source unit 102A. On the other hand, FIG. 2C is a graph showing the change over time of the drive current of the light source unit 102B.

In the variable light distribution type, the most light source is loaded with a light distribution pattern in which the entire surface is illuminated. Therefore, the output of the light source unit is usually set based on the light distribution pattern in which the entire surface shines. In the driving method of the illumination device 101A of the comparative example, both the light sources 102A and 102B are always on (CW: Continuous Wave). The drive current is set to a value that can ensure reliability under this always-on condition. In practice, it has a blanking period, which will be described later.

On the other hand, in the above-described first embodiment, the irradiation positions on the light emitting unit 6 are alternate between the light source unit 2A and the light source unit 2B. Therefore, the pulse driving is such that the light sources 2A and 2B are repeatedly turned on and off (in the first embodiment, for example, the pulse width is 10 μs and the duty is 50%). The reliability of the light source unit is improved because it can be turned off intermittently as compared with always on. This is because the reliability of the light source made of a semiconductor is mainly determined by the junction temperature as described above. That is, by turning off intermittently, the average junction temperature is lowered by cooling during that period. It can also reduce the risk of sudden deterioration.

Further, the current value at the time of turning on can be higher than the value of the comparative example (in the first embodiment, for example, 3.8 A compared to 2.3 A of the comparative example). Although it depends on the pulse width and the duty value, the light output can be twice or more than that at the time of always on (see the second embodiment). Therefore, by setting the pulse width and the duty so as not to flicker, not only the reliability of the light source unit but also the brightness felt by a person can be made equal to or higher than that of the comparative example. The pulse width and duty are set according to the scanning speed and resolution.

Such pulse driving can be applied to an illumination device that does not include the excitation light scanning units 4A and 4B. However, the variable light distribution type as in the present application requires pulse driving for pattern generation. It is more preferable because it need not be added.

(About pulse drive circuit)
The light source scanning type ADB/variable light distribution illumination (that is, the subject of the present application) requires modulation of the light source (more specifically, ON/OFF of the drive current and, in some cases, various modulation). A pulse driving circuit enables such modulation.

Here, in the ADB/variable light distribution illumination, high-speed modulation and high-current operation are required for high resolution and high luminous flux, but such a pulse drive circuit is generally expensive. Therefore, the ADB/variable light distribution illumination that originally requires a high-cost, high-speed, high-current pulse drive circuit is a form suitable for the technique of the present application. On the contrary, although the application to the illumination which is not ADB/variable light distribution is effective, there is a problem that the cost is increased by adding this circuit.

Further, in the comparative example, it is necessary to deal with the drive current by varying the duty in a wide range from 0 to 100% depending on the pattern. On the other hand, in the present embodiment, the drive can be performed with a duty of 50% at the maximum, and the fluctuation of the load of the circuit is small, so that the risk of causing a malfunction can be suppressed. Here, the duty can be set to 100/N% at maximum, where N is the number of scanning lights (or the number of light source units). According to the above configuration, the drive can be performed with a duty of 100/N% at the maximum, and the fluctuation of the load of the circuit is small, so that the risk of causing a malfunction can be suppressed.

In addition, in FIG. 1A, FIG. 1B, and FIG. 2A, each irradiation spot of the light emitting unit 6 or the light emitting unit 106 is circular, and each spot is lined up with a space between them. Is a schematic one for facilitating. Actually, the spot shape and its arrangement can be appropriately modified. The scanning direction is also only a schematic one, and various methods such as zigzag scanning and unidirectional scanning can be used. Further, although the drawings show light distribution patterns in which the entire surface shines, various light distribution patterns can be obtained by not irradiating a part (see FIG. 8). Also in that case, the reliability of the light source unit is improved by the configuration and the driving method of the present embodiment.

(Specific example of the excitation light scanning units 4A and 4B)
A specific example of the excitation light scanning units 4A and 4B is, for example, a polygon mirror. As shown in FIG. 3, different polygon mirrors (excitation light scanning units) 42A and 42B are provided for each scanning light. The respective scanning lights are arranged on the light emitting unit 6 so as to be deflected to the same position at the same time. Therefore, optical systems α3A and 3B and optical systems β5A and 5B (neither of which is shown) can be provided and used. It is preferable that the excitation light scanning unit is symmetrically arranged with respect to the light source unit and the light emitting unit 6 because adjustment is easy.

In the polygon mirrors 42A and 42B of the present embodiment, the angle of each reflecting surface of the rotating mirror 42a with respect to the rotation axis (axis of the rotating mechanism 42b) is different from each other, so that biaxial scanning can be performed with only a single polygon mirror. I have to. As the excitation light scanning section, a galvanomirror capable of uniaxial scanning can be used as well, but since it is necessary to use two galvanomirrors having different scanning directions for biaxial scanning, from the viewpoint of miniaturization. The polygon mirrors 42A and 42B capable of biaxial scanning according to this embodiment are preferable.

Besides, a MEMS mirror can be used. The MEMS mirror capable of biaxial scanning is preferable from the viewpoint of miniaturization, like the polygon mirrors 42A and 42B of this embodiment. However, since the light-reflecting portion of the MEMS mirror is generally weaker in laser resistance than the polygon mirror or the galvano mirror, the polygon mirror or the galvano mirror is preferable from the viewpoint of high output. From the above, as a comprehensive consideration, as the excitation light scanning units 4A and 4B, the polygon mirrors 42A and 42B capable of biaxial scanning are most preferable.

Further, as shown in FIG. 4A, the positions scanned by the respective scanning lights may be different. In the case of the figure, the scanning light passing through the polygon mirror 42A scans the scanning area A2, and the scanning light passing through the polygon mirror 42B scans the scanning area A1.

In the case of the form shown in FIG. 4A, the optical adjustment is easier than in the form shown in FIG. The allocation of the scanning area is not limited to the pattern shown in FIG. 4A, and various patterns are possible. In this case, in order to light up the entire predetermined area, it is necessary to periodically change the part responsible for ON in each scanning area, as shown in FIG. 4B.

In the configuration shown in FIG. 4B, all 32 pixels are scanned during the period of t _{1 to} t ₃₂ , and the light source units 2A and 2B are not turned on at the same time. Therefore, the same effect as that of the first embodiment can be obtained. Further, in the present embodiment, since the spot positions are apart from each other at t _i and t _i+1 , it is possible to suppress local heat generation on the light emitting unit 6. As a result, it is possible to emit light of higher output and obtain high brightness and high luminous flux.

In FIG. 4B, the scanning areas A1 and A2 are vertically divided, and both spots at each time are aligned in the vertical direction, but the present invention is not limited to this. It suffices that all pixels (the entire area of the desired scanning region) are scanned in a predetermined cycle (a period that does not flicker).

The features of this embodiment are summarized as follows.
(1) Scan the areas (scan areas A1 and A2) in which the respective light source units do not overlap each other.
(2) Only one of the spots is turned on at the same time and at a different place, and the other spots are turned off.
(3) However, in a certain cycle (one frame), the on/off pattern is such that the entire plurality of scanning areas A1 and A2 are turned on.

The feature (1) is not essential, and the effect of the present application can be obtained if the features (2) and (3) are satisfied.

The excitation light scanning unit may share the same scanning light with different scanning lights. Also in this case, similarly to the above-described embodiment, the scanning light may be arranged so as to be at the same position at the same time, or the scanning light may be scanned at different positions. .. An optical system is used for the optical adjustment.

Specifically, as shown in FIG. 10, it is possible to combine the scanning lights and then make them incident on the excitation light scanning unit (polygon mirror 42A). As the optical system, for example, a collimator lens L1, a condenser lens L2, and the optical fiber 10 can be used.

For example, a collimator lens L1 is provided in the vicinity of the respective light emitting points of the two laser elements 2c in the light source unit 2C, and both lights are incident to an incident end of an optical waveguide means such as the optical fiber 10 or a rod lens by one condensing lens L2. It is possible to share them by combining them. Other known multiplexing means can be used, but the optical fiber and the rod lens are preferable because they also have the effect of controlling the spot shape and the light intensity distribution within the spot.

[Embodiment 2]
Next, FIG. 5A is a graph showing the change over time of the drive current of the light source unit 2A in the lighting device according to the second embodiment of the present invention. On the other hand, FIG. 5B is a graph showing the change over time of the drive current of the light source unit 2B. FIG. 5C is a graph showing a state in which the graphs of FIGS. 5A and 5B are superimposed. The configuration of the illumination device of this embodiment is the same as that of the illumination device 1A of the first embodiment described above, but the method of controlling the light source units 2A and 2B by the light source control unit 9 is different.

In the present embodiment, the duty of the light source units 2A and 2B is lower than that in the first embodiment (40%), and there is a time when none of the light source units is lit (non-lit). As described above, such driving can be performed if there is no problem in the usage situation such that it is not felt by the human eye. At this time, the on-state current value of each light source unit can be made higher (5.0 A in the present embodiment) than in the first embodiment.

In fact, in any of the embodiments, the light source unit is turned off even when the light source unit is irradiating outside the desired irradiation range such as the outside of the light emitting unit, or when returning in one-way scanning instead of reciprocal scanning. There is time (blanking period) that should be done. Here, the blanking period is not taken into consideration for ease of explanation.

[Embodiment 3]
Next, FIG. 6A is a diagram showing a schematic configuration of an illumination device 1B according to the third embodiment of the present invention. Further, FIG. 6B is a diagram showing a state in which the scanning with the excitation light from the light source unit 2A and the scanning with the excitation light from the light source unit 2B are superimposed. Further, FIG. 6C is a graph showing the change over time of the drive current of the light source unit 2A. On the other hand, FIG. 6D is a graph showing the change over time of the drive current of the light source unit 2B. 6E is a graph showing a state in which the graphs of FIG. 6C and FIG. 6D are superimposed. The configuration of the illumination device 1B according to the present embodiment is the same as that of the illumination device 1A according to the first embodiment described above, but the method of controlling the light source units 2A and 2B by the light source control unit 9 is different.

In the present embodiment, the ON/OFF cycle of each of the light source units 2A and 2B (the cycle of repeating lighting/non-lighting) is made longer than in the other embodiments. For example, the spot 6a originating from the light source unit 2A is scanned from the left end to the right end of the light emitting unit 6 along a straight line, and during that time, it is always in a lighting state. After that, the spot 6a is scanned from the right end to the left end of the light emitting unit 6 along a straight line, and during that time, the spot 6a is always in a non-lighting state. Thereafter, lighting and non-lighting are repeated in the same manner.

On the other hand, the spot 6b originating from the light source unit 2B is scanned along the straight line from the left end to the right end of the light emitting unit 6, and during that time, it is always in the non-illuminated state. After that, the spot 6b is scanned from the right end to the left end of the light emitting unit 6 along a straight line, and during that time, the spot 6b is always in a lighting state. Thereafter, lighting and non-lighting are repeated in the same manner. According to the lighting device 1B of the present embodiment, the ON/OFF cycle is longer than that of the other embodiments, so that the control is relatively easy.

[Embodiment 4]
Next, FIG. 7A is a diagram showing an example of a schematic configuration and a light emitting unit scanning pattern of an illumination device 1C according to a fourth embodiment of the present invention as a modification of the above-described first embodiment. FIG. 7B is a diagram showing another example of the light emitting unit scanning pattern. On the other hand, FIG. 7C is a diagram showing an example of a light distribution pattern corresponding to the light emitting unit scanning pattern shown in FIG. 7A. Next, FIG. 7D is a diagram showing an example of a light distribution pattern corresponding to the light emitting unit scanning pattern shown in FIG. 7B. Further, (e) of FIG. 7 is a graph showing the change over time of the drive current of the light source unit 2A corresponding to the light emitting unit scanning pattern shown in (a) of FIG. On the other hand, (f) of FIG. 7 is a graph showing the change over time of the drive current of the light source unit 2A corresponding to the light emitting unit scanning pattern shown in (b) of FIG.

In the illumination device 1C of the present embodiment, the pulse crest value (ON-time current value) for driving the laser element 2c of the light source unit 2A is changed according to the light projection shape (light distribution pattern) of the light projection unit 7. ing. For example, when the area of the dark portion is half and the area of the bright portion is half as in the light distribution pattern 1 shown in FIG. 7C, the on-state current value is 3.75 A as shown in FIG. I am trying. On the other hand, when the area of the dark portion is three times the area of the bright portion as in the light distribution pattern 2 shown in FIG. 7D, the on-state current value is 5. It is set to 0A.

According to the lighting device 1C described above, the shorter the pulse width and the smaller the duty, the larger the current value during lighting can be. Thereby, bright light distribution variable illumination can be obtained even if the number of light source units is small. Further, the brightness can be adjusted in combination with PWM (Pulse Width Modulation). In addition, in a situation where the on-time current value can be increased, it is easy to make it dark, and the degree of freedom in brightness adjustment increases. In this embodiment, it is not always necessary that the scanning light is plural.

[Embodiment 5]
Next, FIG. 8A is a diagram showing an example of a schematic configuration of a lighting device 1D according to a fifth embodiment of the present invention and an example of a light emitting unit scanning pattern. FIGS. 8B and 8C are diagrams showing another example of the light emitting unit scanning pattern, respectively. Further, FIG. 8D is a graph showing the change over time of the drive current of the light source unit 2A. On the other hand, FIG. 8E is a graph showing the change over time of the drive current of the light source unit 2B. The configuration of the illumination device 1D of the present embodiment is the same as that of the illumination device 1A of the above-described first embodiment, but the method of controlling the light source units 2A and 2B by the light source control unit 9 is different. The present embodiment is a form in which the operation of the first embodiment described above and the operation of the fourth embodiment described above are combined. For example, when the spot 6a derived from the light source unit 2A and the spot 6b derived from the light source unit 2B are overlapped, the same scanning pattern as that of the illumination device 1C of the fourth embodiment described above is obtained. For example, when the scanning pattern shown in FIG. 8B and the scanning pattern shown in FIG. 8C are combined, the scanning pattern shown in FIG. 7B is the same.

In the present embodiment, in the operation of the first embodiment, the pulse crest value (on-time current value) of each laser element 2c of the light source units 2A, 2B, 2C is changed according to the light distribution pattern. As a result, the shorter the pulse width and the smaller the duty, the larger the on-state current value can be. In addition, bright light distribution variable illumination can be obtained even if the number of light source units is small. Furthermore, the brightness can be adjusted in combination with PWM. In a situation where the on-state current value can be increased, it is easy to darken, and the degree of freedom in brightness adjustment increases.

FIG. 9A is a graph showing the change over time of the drive current of the light source unit 2A in another example of the light emitting unit scanning pattern. On the other hand, FIG. 9B is a graph showing the change over time of the drive current of the light source unit 2B in another example of the light emitting unit scanning pattern. Next, (c) of FIG. 9 is a graph showing a state in which the graphs of (d) of FIG. 8 and (e) of FIG. 8 are superimposed. On the other hand, FIG. 9D is a graph showing a state in which the graphs of FIGS. 9A and 9B are superimposed.

[Summary]
An illumination device (1A, 1B, 1D) according to aspect 1 of the present invention includes a plurality of light source units (2A, 2B) that emit excitation light, and a light emitting unit (6) that includes a phosphor that emits light upon receiving the excitation light. ), an excitation light scanning section (4A, 4B) for scanning the spot of the excitation light incident on the light emitting section on the light emitting section, and a projection for projecting the light emission from the light emitting section into a desired light projection shape. And a plurality of the spots, each of the spots is derived from excitation light of each of the plurality of light source units, and the plurality of light source units are turned on and off. And a light source control unit (9) for turning on only one light source unit at the same time.

According to the above configuration, the light source control unit performs control to turn on only one light source unit at the same time. As a result, none of the light source units are continuously turned on, so that the reliability of the light source unit is improved.

The illumination device according to aspect 2 of the present invention is the illumination device according to aspect 1, wherein the excitation light scanning unit scans each of the plurality of spots on the light emitting unit at the same time and at the same position. The control unit turns on only one light source unit and turns off all the other light source units when the scanning positions of the spots are at the same position on the light emitting unit and at the same time. May be controlled. According to the above configuration, even if the light distribution pattern is such that lighting is continuously performed on the scanning line in the light emitting unit, no light source unit is continuously turned on, and reliability of the light source unit is improved.

In the illumination device according to aspect 3 of the present invention, in the aspect 1, the scanning regions in the light emitting portions of the plurality of spots may be different from each other. According to the above configuration, the optical adjustment becomes easier as compared with the case where the scanning regions of the light emitting portions of the plurality of spots are common.

In the illumination device according to aspect 4 of the present invention, in the aspect 1 or 2, the scanning regions in the light emitting portions of the plurality of spots are common, and each of the plurality of spots has the same time, The spots scanned at the same position may be different from each other in scanning position at the time of lighting. According to the above configuration, even if the light distribution pattern is such that lighting is continuously performed on the scanning line in the light emitting unit, no light source unit is continuously turned on, and reliability of the light source is improved.

In the illumination device according to the fifth aspect of the present invention, in any one of the first to fourth aspects, the excitation light scanning section may be composed of a single mirror element. According to the above configuration, since the excitation light scanning unit is composed of a single mirror element, the overall configuration of the optical system becomes simple.

In the illumination device according to aspect 6 of the present invention, in any one of aspects 1 to 4, the excitation light scanning unit may be configured by the same number of mirror elements as the number of excitation light beams to be scanned. According to the above configuration, the excitation light scanning unit can be configured by the mirror element capable of uniaxial scanning, and the degree of freedom in arranging each mirror element is increased.

In the illumination device according to aspect 7 of the present invention, in the aspect 5 or 6, the mirror element forming the excitation light scanning unit may be a polygon mirror. According to the above configuration, the laser resistance can be increased and the device can be downsized.

An illumination device according to aspect 8 of the present invention is the illumination device according to aspect 7, wherein the polygon mirror is capable of biaxial scanning because the respective reflecting surfaces of the plurality of rotating mirrors have different angles with respect to the rotation axis. It may be. According to the above configuration, the number of parts of the optical system can be reduced and the apparatus can be downsized as compared with the case where a polygon mirror capable of uniaxial scanning is used.

The illumination device according to aspect 9 of the present invention is the illumination device according to any one of aspects 1 to 8, wherein when the number of the light source units is N, the maximum duty related to the operation of the light source units is 100/N%. Is also good. According to the above configuration, the drive can be performed with a duty of 100/N% at the maximum, and the fluctuation of the load of the circuit is small, so that the risk of causing a malfunction can be suppressed.

In the illumination device according to aspect 10 of the present invention, in any one of aspects 1 to 9, the pulse crest value for driving the light source unit may be changed according to the projection shape. According to the above configuration, the shorter the pulse width and the smaller the duty, the larger the current value during lighting. Thereby, bright light distribution variable illumination can be obtained even if the number of light source units is small.

An illumination device according to aspect 11 of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that receives the excitation light emitted by the light source unit and emits light, and a light source control unit that drives the light source unit. The light source control unit is configured to drive at least two of the plurality of light source units so as to emit excitation light at different timings. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

An illumination device according to aspect 12 of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that emits light by receiving the excitation light emitted by the light source unit, a light source control unit that drives the light source unit, and the excitation An excitation light scanning unit that controls an irradiation position of light with respect to the light emitting unit, and the light source control unit is configured to emit at least two of the plurality of light source units at different timings. It is configured to be driven. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

An illumination device according to aspect 13 of the present invention includes a plurality of light source units that emit excitation light, a light emitting unit that emits light by receiving the excitation light emitted by the light source unit, and a light source control unit that drives the light source unit. At least two of the plurality of light source units irradiate different positions of the light emitting unit with excitation light, and the light source control unit emits excitation light at different timings of the at least two light source units. It is configured to be driven to. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

An illumination apparatus according to aspect 14 of the present invention is the illumination device according to aspect 11, 12 or 13, wherein the light source control section drives the at least two light source sections such that their respective emission peaks are temporally different. Is also good. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

An illumination device according to aspect 15 of the present invention is the illumination device according to aspect 11, 12 or 13, wherein the light source control unit includes the at least two light source units each having a light emission output of 75% or more of a peak value. The configuration may be such that the driving is performed so as not to occur. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

An illumination device according to aspect 16 of the present invention is the illumination device according to aspect 11, 12 or 13, wherein the light source control unit has a plurality of output circuits that each output a drive signal for driving one corresponding light source unit. The drive signal is configured to be generated based on a timing signal input to the output circuit, and the timing signal is such that at least two output circuits of the output circuits emit the drive signal at different timings. The configuration may be controlled. According to the above configuration, none of the light source units are continuously turned on, and the reliability of the light source is improved.

[Appendix]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each of the embodiments.

1A-1D Illumination device 2A, 2B, 2C Light source part 4A, 4B Excitation light scanning part 6 Light emitting part 6a, 6b Spot 7 Light projecting part 9 Light source control part 42A, 42B Polygon mirror (excitation light scanning part)

Claims (9)

A plurality of light source units that emit excitation light, a light emitting unit that includes a phosphor that receives the excitation light and emits light, and an excitation light scanning unit that scans the spot of the excitation light that is incident on the light emitting unit on the light emitting unit. And a light projecting unit that projects light emitted from the light emitting unit into a desired light projecting shape,
The spot is a plurality, each of the spots are derived from the respective excitation light of the plurality of light source units,
A light source control unit is provided for turning on and off the plurality of light source units and for turning on only one light source unit at the same time ,
In the light projection shape, the light source control unit includes a light source that has a dark area which is not projected and a bright area which is projected, the larger the area of the dark area is with respect to the area of the bright area. An illuminating device characterized by increasing a pulse crest value for driving a unit. The excitation light scanning unit scans each of the plurality of spots on the light emitting unit at the same time and at the same position,
The light source control unit turns on only one light source unit when all the scanning positions of the spots are at the same position on the light emitting unit and at the same time, and all the other light source units are turned on. The lighting device according to claim 1, wherein the lighting device is controlled to be turned off. The illumination device according to claim 1, wherein the scanning areas of the light emitting units of the plurality of spots are different from each other. The scanning area in each of the light emitting units of each of the plurality of spots is common, each of the plurality of spots is scanned at the same position at the same time, and the respective scanning positions of the spots at the time of lighting are mutually different. The lighting device according to claim 1 or 2, which is different. The illumination device according to any one of claims 1 to 4, wherein the excitation light scanning unit includes a single mirror element. The illumination device according to any one of claims 1 to 4, wherein the excitation light scanning unit is composed of the same number of mirror elements as the number of scanning excitation lights. The illumination device according to claim 5 or 6, wherein the mirror element forming the excitation light scanning unit is a polygon mirror. 8. The illumination device according to claim 7, wherein the polygon mirror is capable of biaxial scanning because the angles of the respective reflecting surfaces of the plurality of rotating mirrors with respect to the rotation axis are different from each other. The illumination device according to any one of claims 1 to 8, wherein, when the number of the light source units is N, the maximum duty related to the operation of the light source units is 100/N%.

Images