JP2018103868A - Illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device in which any defect and missing of a phosphor plate can be detected while suppressing a cost of manufacture thereof.SOLUTION: A vehicle head lamp device 1 comprises: a light source 5; a phosphor plate 6 into which laser beam exited from the light source 5 is entered and exits fluorescent light; a condenser lens 7 for condensing light; a digital mirror 8 which reflects light from the condenser lens 7 by each mirror element; a projection lens 9 which projects light reflected by the digital mirror 8 to an irradiation region S; and a control unit 3 which controls a tilt mode of plural mirror elements 8a and an output of the light source 5. The digital mirror 8 comprises a photodiode 8d for detecting fluorescent light in a region other than an arrangement range of the plural mirror elements range of a condensation region. The control unit 3 stops output of the light source 5 in the case the photodiode 8d does not detect fluorescent light during light-emitting elements 5a, 5b are driven.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an illumination device using a phosphor.

  In recent years, an illumination device that irradiates light emitted from a laser device to a light emitting portion made of a phosphor and emits fluorescence excited by the light emitting portion forward by a projection lens has been widely used and used for a vehicle headlight or the like. It has been.

  For example, the light-emitting device disclosed in Patent Document 1 below includes a laser light source, a control unit, a lens, a phosphor, a substrate, a detection unit, and the like. The substrate is provided with a number of first micromirrors for reflecting the fluorescence and projecting it forward, and a second micromirror for reflecting the fluorescence or laser light to the detection unit in the middle of the arrangement of the first micromirrors. Includes a mirror.

  The detection unit is configured to have higher detection sensitivity to laser light than fluorescence. Further, when the value of the detection signal is equal to or greater than a predetermined threshold, the control unit determines that the laser beam is detected instead of the fluorescence due to a defect in the phosphor, and stops emitting the laser beam ( Patent Document 1 / paragraphs 0017, 0025, 0030, FIG. 1).

Japanese Patent Laid-Open No. 2006-162682

  However, the light emitting device of Patent Document 1 can prevent leakage of laser light to the outside, but is a special device including a dedicated second micromirror for detecting a defect in a phosphor, Existing devices cannot be used. For this reason, there existed a problem that manufacturing cost was high.

  This invention is made | formed in view of such a situation, and it aims at providing the illuminating device provided with the defect detection function of a fluorescent substance, suppressing manufacturing cost.

  The present invention includes a light emitting unit composed of a light emitting element, a phosphor that emits fluorescence by making light emitted from the light emitting unit incident thereon, and a condensing optical unit that collects the fluorescence emitted from the phosphor. A plurality of mirror elements that can be tilted, and a collective mirror part that reflects the fluorescence from the condensing optical part by each mirror element, and the light reflected by the collective mirror part is projected onto an irradiation area An illumination device comprising: a projection optical unit; and a control unit that controls an inclination mode of a plurality of mirror elements of the collective mirror unit and an output of the light emitting unit, wherein the collective optical unit to the collective mirror unit The light emitted to the light source includes a light-condensing region that includes the array range of the plurality of mirror elements and is wider than the array range, and the light is emitted in a region other than the region of the array range in the light-collecting region. A light detector that detects fluorescence from the optical optics For example, the control unit, the light detecting portion when the light emitting element is driven when detecting no fluorescence is characterized by stopping the output of the light emitting element.

  In the illuminating device of the present invention, the fluorescence emitted from the phosphor is condensed by the condensing optical unit and enters the collective mirror unit. The collective mirror unit reflects the light from the condensing optical unit toward the projection optical unit. At this time, a control part produces | generates a light distribution pattern by controlling the inclination aspect of the some mirror element of an assembly mirror part, and the output of a light emission part.

  The fluorescence from the condensing optical part includes a range of arrangement of a plurality of mirror elements, and forms a condensing region wider than the range of arrangement. Moreover, the light detection part is arrange | positioned in the area | regions other than the arrangement | sequence range among condensing areas. In this case, it is not necessary to use a dedicated collective mirror part that increases the cost in order to detect defects or defects in the phosphor, and a general-purpose collective mirror part can be used.

  While the fluorescence is detected by the light detection unit, the fluorescence is incident on the collective mirror unit. However, when fluorescence is no longer detected, there is a possibility that the light from the light emitting element is directly incident on the collective mirror part due to a defect or lack of the phosphor. Therefore, when the fluorescence is not detected during the power supply to the light emitting element, the control unit stops the output of the light emitting unit and controls the light from the light emitting element not to be emitted to the outside. Therefore, by using an existing mirror device, it is possible to provide a lighting device that can detect defects and missing parts of phosphors while suppressing manufacturing costs.

  In the illuminating device of the present invention, it is preferable that the illumination device further includes a light shielding unit that shields light from other than the condensing optical unit so as not to enter the light detection unit.

  According to this configuration, since the light detection unit is provided with the light shielding unit, light does not enter the light detection unit from other than the condensing optical unit. Thereby, the light detection unit can accurately detect the incidence of fluorescence.

  Moreover, the illuminating device of this invention WHEREIN: It is preferable that the said light-shielding part is a shape which covers at least one part of the circumference | surroundings of the said light detection part.

  According to this configuration, for example, by providing a cylindrical light shielding unit in the light detection unit, it is possible to block light from various directions incident on the light detection unit. Thereby, the light detection unit can detect the incidence of fluorescence more accurately.

  In the illumination device according to the aspect of the invention, it is preferable that the light shielding unit is arranged in parallel with an optical axis of fluorescence from the condensing optical unit.

  According to this configuration, when the fluorescence from the condensing optical unit enters the collective mirror unit or the light detection unit, it is not blocked by the light shielding unit.

  In the illumination device of the present invention, the phosphor is circular, the array range of the plurality of mirror elements is rectangular, and the fluorescence from the condensing optical unit forms a circular condensing region. Is preferred.

  According to this configuration, if the light collection region (circular) is made wider than the arrangement range (rectangle) of the plurality of mirror elements, a certain amount of light collection region necessarily exists outside the arrangement range. And this outside condensing area | region can be utilized effectively as a location which arrange | positions a photodetector.

The figure which shows the whole structure of the illuminating device (vehicle headlamp apparatus) of 1st Embodiment. The figure explaining the optical system of an illuminating device. The front view of the digital mirror of FIG. 2A. The figure explaining the optical system of the illuminating device of 2nd Embodiment. The front view of the digital mirror of FIG. 3A. FIG. 3B is a front view of the digital mirror in FIG.

Hereinafter, embodiments of the illumination device of the present invention will be described.
(First embodiment)

  FIG. 1 is a configuration diagram of a vehicle headlamp device 1 which is an example of a lighting device. The vehicle headlamp device 1 is mounted on a vehicle, and mainly includes an optical system device 2, a control device 3, and an imaging device 4.

  In the vehicle headlamp device 1, first, the imaging device 4 provided in front of the vehicle (for example, on the windshield side of the rearview mirror) images the front of the vehicle. Then, the control device 3 acquires and analyzes the captured image information, and controls the optical system device 2. Thereby, the front of a vehicle can be irradiated with a predetermined light distribution pattern.

  The optical system device 2 includes a light source 5, a phosphor plate 6, a condenser lens 7, a digital mirror 8, and a projection lens 9, and these members are housed in a casing 10.

  The light source 5 is, for example, a blue laser diode (hereinafter referred to as LD) having a central emission wavelength of 450 nm. The LD (the “light emitting element” of the present invention) constituting the light source 5 can be controlled to be turned on / off and the amount of light (output) by the light source control unit 13 described later.

  The phosphor plate 6 (the “phosphor” of the present invention) is disposed between the light source 5 and the condenser lens 7. The phosphor plate 6 emits fluorescence when irradiated with the laser light emitted from the light source 5. Here, the phosphor plate 6 is preferably circular or elliptical. As a result, the fluorescent condensing region (spot) emitted from the condensing lens 7 and incident on the digital mirror 8 becomes circular or elliptical.

  The condensing lens 7 (the “condensing optical unit” of the present invention) is, for example, a convex lens, and is disposed at a position where the light from the phosphor plate 6 is collected and emitted to the digital mirror 8. . The light emitted from the phosphor plate 6 spreads with a predetermined radiation angle, but is collected by passing through the condenser lens 7 and enters the digital mirror 8.

  The digital mirror 8 (the “aggregation mirror part” of the present invention) reflects the light incident from the condenser lens 7 and emits it toward the projection lens 9. The digital mirror 8 has a rectangular structure in which a plurality of mirror elements provided to be tiltable are arranged in an array. The tilt mode (reflection angle) of each mirror element is controlled by an actuator control unit 14 described later.

  The digital mirror 8 is a device in which a mirror section in which mirror elements of several tens of μm square are arranged is housed in a mirror package. Each mirror element can reflect incident light in two directions (for example, one of + 12 ° and −12 °).

  In the optical system device 2, when the light incident on the mirror element is reflected in one direction, the light travels in the direction of the projection lens 9, so that the light forms a bright portion of the light distribution pattern. Further, when the light incident on the mirror element is reflected in the other direction, the light deviates from the projection lens 9, thereby forming a dark portion of the light distribution pattern.

  That is, various light distribution patterns can be generated in the irradiation region S by controlling the tilting mode of the mirror element by the actuator control unit 14.

  The projection lens 9 (the “projection optical unit” in the present invention) is disposed between the digital mirror 8 and the irradiation region S. The light incident from the digital mirror 8 passes through the projection lens 9 and the translucent cover 10a of the casing 10 and forms an image on the irradiation area S in front of the vehicle. The optical system device 2 is mounted at least on the left and right sides of the front portion of the vehicle.

  The control device 3 (the “control unit” of the present invention) includes, for example, a controller 11, a memory 12, a light source control unit 13, and an actuator control unit 14. The controller 11 calculates a light distribution pattern based on a captured image signal in front of the vehicle of the imaging device 4. Further, the controller 11 outputs a control signal for irradiating the irradiation region S with the calculated light distribution pattern to the light source control unit 13 and the actuator control unit 14. Thereby, the controller 11 can change the illumination distribution of the light distribution pattern irradiated to the irradiation area S.

  The memory 12 includes a RAM that is used to temporarily store predetermined data when the controller 11 performs an operation, a ROM that stores program data executed by the controller 11, and a predetermined nonvolatile storage device.

  The light source control unit 13 controls on / off of the light source 5 of the optical system device 2, change of the light amount, and driving power supplied to the light source 5. The actuator control unit 14 supplies driving power to the digital mirror 8 of the optical system device 2 and controls the tilting mode of each mirror element.

  The imaging device 4 should just be what can image the vehicle front. For example, a digital camera capable of capturing visible light and infrared light can be used, but a camera for monitoring a pedestrian or an obstacle may be used for the purpose of preventing collision of the vehicle.

  Next, the optical system of the vehicle headlamp apparatus 1 shown in FIG. 1 will be described with reference to FIGS. 2A and 2B.

  As shown in FIG. 2A, the light source 5 is composed of two LDs 5a and LD5b in order to secure a light quantity. The light source 5 may be composed of three or more LDs. The light source 5 may be a light emitting diode (LED) as long as a sufficient amount of light can be secured.

  When the laser beams of the LD 5 a and LD 5 b enter the phosphor plate 6, the phosphor is excited and emits fluorescence, and the light from the phosphor plate 6 including the fluorescence is collected by the condenser lens 7. Then, the light condensed by the condenser lens 7 is incident on the mirror portion 8 a of the digital mirror 8. The mirror portion 8a is sealed in a package for protection, and a cover glass 8b is attached to the front surface of the mirror portion 8a. The cover glass 8b is held by the glass holding member 8c, and no light enters from the glass holding member 8c.

  In addition, a photodiode 8d (the “photodetector” of the present invention) is disposed on the front surface (downward) of the cover glass 8b. The photodiode 8 d is a sensor that detects fluorescence from the condenser lens 7.

  When the light distribution pattern is generated, the fluorescence is detected by the photodiode 8d. However, when the light distribution pattern is not detected (including the case where the detected fluorescence falls below the threshold), the phosphor plate 6 has a defect or There is a possibility that the laser light of the LD 5a and LD 5b is directly incident on the digital mirror 8 due to the omission. At this time, since the light source control unit 13 controls the light source 5 to be turned off, the laser light can be prevented from being reflected by the digital mirror 8 and directly emitted to the outside.

  FIG. 2B shows the digital mirror 8 as viewed from the front side where light enters. At the time of generating the light distribution pattern, the condensed fluorescent image becomes a condensing region R larger than that of the mirror portion 8a. The condensing region R depends on the size of the phosphor plate 6 and the magnification of the condensing lens 7, but here, the fluorescent light is incident on the entire mirror portion 8a. In addition, since the photodiode 8d is disposed in the condensing region R and at a position that does not overlap the mirror portion 8a when viewed from the front, the photodiode 8d effectively utilizes the fluorescence that does not enter the mirror portion 8a, and Defects can be detected.

  Then, the fluorescence reflected by the mirror portion 8a of the digital mirror 8 enters the projection lens 9, and finally a light distribution pattern is generated in the irradiation region S.

(Second Embodiment)
Next, with reference to FIG. 3A, FIG. 3B, and FIG. 4, digital mirror 8 'of the vehicle headlamp apparatus 1' of 2nd Embodiment is demonstrated. Note that the same components as those in FIGS. 2A and 2B are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 3A, disturbance light including a yellow component may be incident on the photodiode 8d of the digital mirror 8 'in addition to the fluorescence generated from the laser light of the LD 5a and LD 5b.

  As described above, when fluorescence is no longer detected by the photodiode 8d when generating the light distribution pattern, the light source control unit 13 turns off the light source 5. However, since the photodiode 8d may detect disturbance light, the digital mirror 8 ′ has a light shielding plate 8e (the “light shielding portion” of the present invention) that blocks the incidence of disturbance light on the photodiode 8d. (See FIGS. 3A and 3B).

  The light shielding plate 8e is a black thin plate made of metal or plastic. As shown in FIG. 3A, the light shielding plate 8e can prevent disturbance light from at least a direction different from the light source 5 from entering the photodiode 8d.

  Further, the light shielding plate 8e is attached to the cover glass 8b in parallel with the optical axis L of the fluorescent light so as not to prevent the fluorescent light from entering the mirror part 8a and the photodiode 8d and to prevent reflection by the mirror part 8a. Yes.

  Further, as shown in FIG. 4, a light shielding plate 8e 'having a shape covering the periphery of the photodiode 8d except for the lower portion of the photodiode 8d may be used. As for the light shielding plate 8e ', the upper part of the photodiode 8d is attached to the cover glass 8b in parallel with the optical axis L of fluorescence.

  As a result, it is possible to more reliably prevent disturbance light from entering the photodiode 8d, so that fluorescence can be detected more accurately. A cylindrical light shielding member that covers the entire periphery of the photodiode 8d may be used.

  As described above, the vehicle headlamp device 1 includes the photodiode 8 d that detects fluorescence from the condenser lens 7 on the front side of the digital mirror 8. Then, the control device 3 stops the output of the light source 5 (LD5a, LD5b) when the photodiode 8d does not detect fluorescence during execution of the control for changing the light distribution pattern. Thereby, the illuminating device provided with the defect detection function of the fluorescent substance plate 6 can be provided by suppressing the manufacturing cost using the existing micromirror device.

  The above embodiment is an example of an embodiment of the present invention, and various modifications can be considered besides this. Although the condensing lens 7 has been described as the condensing optical unit of the present invention, for example, a curved mirror may be used. Fluorescence can also be condensed and guided to the digital mirror 8 by a curved mirror.

  DESCRIPTION OF SYMBOLS 1,1 '... Vehicle headlamp apparatus, 2 ... Optical system apparatus, 3 ... Control apparatus (control part), 4 ... Imaging apparatus, 5 ... Light source, 5a, 5b ... LD (light emitting element), 6 ... Phosphor Plate, 7 ... Condensing lens (condensing optical part), 8, 8 '... Digital mirror (collecting mirror part), 8a ... Mirror part, 8b ... Cover glass, 8c ... Glass holding member, 8d ... Photodiode (light detection) Part), 8e, 8e '... light shielding plate, 9 ... projection lens (projection optical part), 10 ... casing, 10a ... translucent cover, 11 ... controller, 12 ... memory, 13 ... light source control part, 14 ... actuator control part .

Claims (5)

A light-emitting unit comprising a light-emitting element;
A phosphor that emits fluorescence by making the light emitted from the light emitting portion incident; and
A condensing optical unit that condenses the fluorescence emitted from the phosphor;
A plurality of mirror elements that can be tilted are arranged, an assembly mirror part that reflects the fluorescence from the condensing optical part by each mirror element, and
A projection optical unit that projects light reflected by the collective mirror unit onto an irradiation area;
A control unit that controls a tilt mode of the plurality of mirror elements of the collective mirror unit and an output of the light emitting unit, and a lighting device comprising:
The light emitted from the condensing optical unit to the collective mirror unit includes an array range of the plurality of mirror elements, and forms a condensing region wider than the array range,
A light detection unit that detects fluorescence from the light collecting optical unit in a region other than the region of the arrangement range in the light collecting region,
The control device stops the output of the light emitting element when the light detection unit does not detect fluorescence when the light emitting element is driven. The lighting device according to claim 1.
An illuminating device, further comprising: a light shielding unit that shields light from a part other than the condensing optical unit so that the light does not enter the light detection unit. The lighting device according to claim 2,
The illumination device according to claim 1, wherein the light shielding part has a shape covering at least a part of the periphery of the light detection part. The lighting device according to claim 2 or 3,
The illuminating device characterized in that the light-shielding part is arranged in parallel with an optical axis of fluorescence from the condensing optical part. In the illuminating device of any one of Claims 1-4,
The phosphor is circular,
The array range of the plurality of mirror elements is rectangular,
The fluorescent light from the condensing optical unit forms a circular condensing region.