Illumination device and illumination method

Abstract

The lighting device (1) includes: a light source (2) that emits coherent light; a scanning unit (5) that scans the coherent light emitted from the light source; a first optical system (6) that adjusts the optical path of the coherent light from the scanning unit; a first optical component (7) that diffuses the coherent light from the first optical system; and a second optical system (8) that adjusts the optical path of the coherent light from the first optical component. The illuminated area (LZ) on the irradiated surface (PP) is illuminated with the coherent light emitted from the second optical system. The irradiance [W / m<supgt;2< / supgt;] in a plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area is non-discrete.

Description

Technical Field

[0001] The present disclosure relates to a lighting device and a lighting method. Background Art

[0002] A laser light source emits coherent light. A laser light source generally has the following advantages. A laser light source has a smaller light-emitting area than an LED (Light Emitting Device). A laser light source can irradiate light to a distant place by having directivity. The lifespan of a laser light source is longer than that of a high-pressure mercury lamp or the like. A laser light source can miniaturize an optical system. A laser light source consumes less power. Due to these advantages, lighting devices and projection devices using a laser light source have been increasingly popularized.

[0003] Conventionally, as disclosed in Japanese Patent No. 4290095, a lighting device using a laser light source has been proposed. The lighting device includes a light source, a scanning unit that scans light, a first optical system, a second optical system, and an optical component. The light source emits coherent light. The first optical system forms an intermediate image using the light from the scanning unit. The second optical system forms an image of the light from the intermediate image on an actual display surface. The optical component is disposed at the position of the intermediate image between the first optical system and the second optical system. The optical component decomposes the light emitted from the first optical system into a plurality of diffracted lights that enter the display surface at different incident angles by diffraction.

[0004] The laser light emitted from the laser light source of the above lighting device has high coherence and very high light intensity. Therefore, when the human eye is exposed to the laser, it may cause adverse effects.

[0005] In the lighting device described in the above Patent Document 1, the light from the second optical system enters a display surface such as a screen in a discretely diffused state. Generally, if the beam spot on a plane perpendicular to the optical axis of the light from the second optical system is large, the influence on the human eye can be mitigated. However, within the beam spot of the light emitted from the second optical system, there are discretely high-intensity lights. Therefore, the lighting device disclosed in Japanese Patent No. 4290095 is not sufficient in terms of safety.

[0006] Above, a lighting device having a laser light source is exemplified to illustrate the conventional problems. Such problems occur in lighting devices having a light source that emits coherent light. Summary of the Invention

[0007] In view of the above problems, an object of the present disclosure is to improve safety in a lighting device having a light source that emits coherent light.

[0008] As one aspect of the present disclosure, there is provided an illumination device, which includes: a light source that emits coherent light; a scanning unit that scans the coherent light emitted from the light source; a first optical system that diffuses and irradiates the coherent light from the scanning unit at a first divergence angle; a first optical component that diffuses and irradiates the coherent light from the first optical system at a second divergence angle; and a second optical system that irradiates the coherent light from the first optical component toward an illuminated area, where the second divergence angle is larger than the first divergence angle, and the light intensity in a plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area is substantially uniform.

[0009] Alternatively, the spot of the coherent light irradiated onto the illuminated area may be a substantially elliptical shape with a major axis exceeding 7 mm in size. Alternatively, the first optical component may be disposed at the rear focal position of the first optical system and the front focal position of the second optical system. Alternatively, the light intensity at the center in the spot plane of the coherent light perpendicular to the optical axis of the coherent light irradiated from the first optical component onto the second optical system is weaker than the light intensity at the outer periphery in the spot plane.

[0010] The scanning frequency of the coherent light in the scanning unit may also be 15 Hz or more. In this case, the scanning unit may scan the coherent light along the shape of a specified pattern.

[0011] The illumination device further includes a second optical component that is irradiated with the coherent light from the second optical system. The second optical system may emit substantially parallel light, and the spot of the coherent light irradiated onto the second optical component may be a substantially elliptical shape with a major axis exceeding 7 mm in size.

[0012] Alternatively, it may include: a plurality of the light sources that can emit a plurality of the coherent lights with different wavelengths; and a plurality of the second optical components corresponding to the plurality of the coherent lights respectively. Alternatively, it may include a plurality of the light sources that can emit a plurality of the coherent lights with different wavelengths, and the scanning unit scans the coherent light in a scanning area corresponding to the size of each wavelength of the plurality of the coherent lights.

[0013] The illumination device of the present disclosure includes:

[0014] a light source that emits coherent light;

[0015] a scanning unit that scans the coherent light emitted from the light source;

[0016] a first optical system that adjusts the optical path of the coherent light from the scanning unit;

[0017] A first optical component that diffuses the coherent light from the first optical system; and

[0018] A second optical system that adjusts the optical path of the coherent light from the first optical component,

[0019] Illuminates an illuminated area on the irradiated surface with the coherent light emitted from the second optical system,

[0020] The irradiance [W / m 2 in a plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area is non-discrete.

[0021] In the illumination device of the present disclosure, it may also be that the incident position of the coherent light on the irradiated surface changes according to the optical path of the coherent light determined by the scanning unit.

[0022] In the illumination device of the present disclosure, it may also be that the incident angle at which the coherent light enters the first optical system, the incident position at which the coherent light enters the first optical system, the incident position at which the coherent light enters the first optical component, the emission direction of the coherent light from the second optical system, and the incident position of the coherent light on the irradiated surface change according to the optical path of the coherent light determined by the scanning unit.

[0023] In the illumination device of the present disclosure, it may also be that the emission direction of the coherent light from the second optical system changes according to the incident position at which the coherent light enters the first optical component.

[0024] In the illumination device of the present disclosure, it may also be that the incident position at which the coherent light enters the first optical component changes according to the optical path of the coherent light determined by the scanning unit.

[0025] In the illumination device of the present disclosure, it may also be that the spot of the coherent light irradiated onto the illuminated area has a maximum width exceeding 7 mm.

[0026] In the illumination device of the present disclosure, it may also be that the first optical component is provided at the rear focal position of the first optical system and the front focal position of the second optical system.

[0027] In the illumination device of the present disclosure, it may also be that the irradiance [W / m 2 at the center within the spot of the coherent light irradiated from the first optical component onto the second optical system is lower than the irradiance [W / m 2 at the outer periphery within the spot.

[0028] In the lighting device of the present disclosure, alternatively, the second optical system may converge the coherent light from the first optical component onto the illuminated surface.

[0029] In the lighting device of the present disclosure, alternatively, the lighting device may further include a second optical component that directs the coherent light from the second optical system toward the illuminated area on the illuminated surface.

[0030] In the lighting device of the present disclosure, alternatively, the spot of the coherent light irradiated onto the second optical component may have a maximum width exceeding 7 mm.

[0031] In the lighting device of the present disclosure, alternatively, the second optical component may converge the coherent light from the second optical system onto the illuminated surface.

[0032] In the lighting device of the present disclosure, alternatively, the scanning frequency of the coherent light in the scanning unit may be 15 [Hz] or more.

[0033] In the lighting device of the present disclosure, alternatively, the scanning unit may scan the coherent light along a specified pattern.

[0034] In the lighting device of the present disclosure, alternatively, the emission direction of the coherent light from the second optical system may vary according to the optical path determined by the scanning unit, and by scanning the coherent light by the scanning unit, the incident position of the coherent light is moved within the illuminated area visually recognized as a specified pattern.

[0035] In the lighting device of the present disclosure, alternatively, the emission direction of the coherent light from the second optical component may vary according to the optical path determined by the scanning unit, and by scanning the coherent light by the scanning unit, the incident position of the coherent light is moved within the illuminated area visually recognized as a specified pattern.

[0036] In the lighting device of the present disclosure, alternatively, the incident position of the coherent light is moved on the illuminated surface in such a manner that the specified pattern visually recognized moves on the illuminated surface.

[0037] In the lighting device of the present disclosure, alternatively, the second optical component diffuses the coherent light from the second optical system and expands and projects the coherent light in the illuminated area having a specified pattern on the illuminated surface.

[0038] In the lighting device of the present disclosure, it is also possible that the emission direction of the coherent light from the second optical component varies according to the optical path determined by the scanning unit, and the specified pattern that can be visually recognized is moved on the irradiated surface by scanning the coherent light by the scanning unit.

[0039] In the lighting device of the present disclosure, it is also possible that the scanning frequency of the coherent light in the scanning unit is less than 15 [Hz].

[0040] In the lighting device of the present disclosure, it is also possible that the emission direction of the coherent light from the second optical component varies according to the incident direction of the coherent light from the second optical system toward the second optical component, the incident direction of the coherent light from the second optical system toward the second optical component varies according to the optical path determined by the scanning unit, and the incident direction of the coherent light from the second optical system toward the second optical component changes at a speed of 800 [° / second] or less.

[0041] In the lighting device of the present disclosure, it is also possible that the moving speed of the illuminated area on the irradiated surface is 140 mm / second or less.

[0042] In the lighting device of the present disclosure, it is also possible that the emission direction of the coherent light from the second optical component varies according to the optical path determined by the scanning unit, and the coherent light is scanned by the scanning unit in such a way that a plurality of the specified patterns can be visually recognized on the irradiated surface.

[0043] In the lighting device of the present disclosure, it is also possible that the scanning frequency of the coherent light in the scanning unit is 15 [Hz] or more.

[0044] In the lighting device of the present disclosure, it is also possible that the light source intermittently emits the coherent light.

[0045] In the lighting device of the present disclosure, it is also possible that the emission direction of the coherent light from the second optical component varies according to the incident direction of the coherent light from the second optical system toward the second optical component, the incident direction of the coherent light from the second optical system toward the second optical component varies according to the optical path determined by the scanning unit, and the incident direction of the coherent light from the second optical system toward the second optical component changes faster than 800 [° / second].

[0046] In the lighting device of the present disclosure, it may also be that, within the region through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light from the lighting device toward the illuminated area, the distribution of the irradiance along a certain direction does not include a minimum value within the range between two half-value positions where the irradiance is half of the maximum irradiance on both sides of the maximum position where the maximum irradiance can be obtained, or if there is a minimum value within the range, the ratio of the difference between the smaller maximum value of the irradiance obtained at two maximum positions on both sides of the minimum value position where the minimum value can be obtained and the minimum value to the smaller maximum value is 20 [%] or less.

[0047] In the lighting device of the present disclosure, it may also be that, regarding the distribution of the irradiance along a certain direction within the region through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light from the lighting device toward the illuminated area, within a range of 70 [%] or more within the range between two half-value positions where the irradiance is half of the maximum irradiance on both sides of the maximum position where the maximum irradiance can be obtained, the irradiance is 80 [%] or more of the maximum irradiance.

[0048] In the lighting device of the present disclosure, it may also be that the light source includes a plurality of light sources that emit coherent light with different wavelengths, and the second optical component includes a plurality of second optical components corresponding to the coherent light from the plurality of light sources respectively.

[0049] In the lighting device of the present disclosure, it may also be that the light source includes a plurality of light sources that emit coherent light with different wavelengths, and the size of the scanning region on the first optical component where the coherent light is incident is different among the coherent light from the plurality of light sources.

[0050] In the lighting device of the present disclosure, it may also be that the scanning region of the first coherent light in the first band is smaller than the scanning region of the second coherent light in the second band that is shorter than the first band.

[0051] In the lighting device of the present disclosure, it may also be that the scanning region of the first coherent light in the first band is included in the scanning region of the second coherent light in the second band that is shorter than the first band.

[0052] In the lighting device of the present disclosure, it may also be that the light source includes a plurality of light sources that emit coherent light with different wavelengths, and the irradiance [W / m 2 at the center within the region through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light emitted from each light source is lower than the irradiance [W / m 2 at the outer periphery of the region.

[0053] The lighting method of the present disclosure includes:

[0054] A step of preparing a lighting device, the lighting device including: a light source that emits coherent light; a scanning unit that scans the coherent light emitted from the light source; a first optical system that adjusts the optical path of the coherent light from the scanning unit; a first optical component that diffuses the coherent light from the first optical system; and a second optical system that adjusts the optical path of the coherent light from the first optical component; and

[0055] A lighting step of illuminating an illuminated area on an irradiated surface with the coherent light emitted from the second optical system,

[0056] In the lighting step, the scanning unit is used to change the optical path of the coherent light, thereby changing the emission direction of the coherent light from the second optical system and moving the incident position of the coherent light on the irradiated surface.

[0057] In the lighting method of the present disclosure, it may also be that the incident position of the coherent light is moved within the illuminated area to illuminate the illuminated area in a manner that is visually recognized as a specified pattern.

[0058] In the lighting method of the present disclosure, it may also be that the incident position of the coherent light is moved on the irradiated surface in a manner that the specified pattern visually recognized moves on the irradiated surface.

[0059] In the lighting method of the present disclosure, it may also be that the lighting device further includes a second optical component that diffuses the coherent light from the second optical system and expands the coherent light in the illuminated area having a specified pattern on the irradiated surface. In the lighting step, the scanning unit is used to change the optical path of the coherent light, thereby moving the specified pattern visually recognized on the irradiated surface.

[0060] In the lighting method of the present disclosure, it may also be that the lighting device further includes a second optical component that diffuses the coherent light from the second optical system and expands the coherent light in the illuminated area having a specified pattern on the irradiated surface, and the coherent light is scanned by the scanning unit in a manner that a plurality of the specified patterns are visually recognized on the irradiated surface.

[0061] According to the present disclosure, the safety of a lighting device having a light source that emits coherent light can be improved. Description of the Drawings

[0062] Figure 1It is a schematic structural diagram of the lighting device for explaining the first embodiment of the present disclosure.

[0063] Figure 2 It is a partial enlarged view showing the schematic structure near the first optical component included in the lighting device.

[0064] Figure 3 It is an explanatory diagram of a method of scanning coherent light in a pattern on the incident surface of the first projection optical system.

[0065] Figure 4 It is an explanatory diagram of a method of scanning coherent light in a pattern on the incident surface of the first projection optical system.

[0066] Figure 5A It is a graph showing an example of the distribution of irradiance within the beam spot.

[0067] Figure 5B It is a graph showing another example of the distribution of irradiance within the beam spot.

[0068] Figure 5C It is a graph showing yet another example of the distribution of irradiance within the beam spot.

[0069] Figure 6 It is a schematic structural diagram of the lighting device for explaining the second embodiment of the present disclosure.

[0070] Figure 7 It is a schematic structural diagram of the lighting device for explaining the third embodiment of the present disclosure.

[0071] Figure 8 It is for explaining that it can be in Figure 7 A perspective view of an example of the second optical component that can be used in the lighting device.

[0072] Figure 9 It is for explaining that it can be in Figure 7 A perspective view of another example of the second optical component that can be used in the lighting device.

[0073] Figure 10 It is a graph comparing and showing the diffraction characteristics of the second optical component with respect to coherent light of the design wavelength and the diffraction characteristics of the second optical component with respect to coherent light of a wavelength different from the design wavelength.

[0074] Figure 11 It is a diagram for explaining a modification example of the lighting device of the third embodiment, and is a schematic structural diagram showing the vicinity of the second projection optical system and the second optical component.

[0075] Figure 12 It is a diagram for explaining another modification example of the lighting device of the third embodiment.

[0076] Figure 13A It is a top view showing an example of an illuminated area on an irradiated surface.

[0077] Figure 13B It is a top view showing another example of an illuminated area on an irradiated surface.

[0078] Figure 13C It is a top view showing still another example of an illuminated area on an irradiated surface.

[0079] Figure 14 It is a diagram for explaining a modified example of the second projection optical system.

[0080] Figure 15 It is a diagram for explaining an example of the illumination method in the second embodiment.

[0081] Figure 16 It is a diagram for explaining a modified example of the second optical component.

[0082] Figure 17 It is a diagram for explaining another example of the illumination method in the second embodiment.

[0083] Figure 18 It is a diagram for explaining still another example of the illumination method in the second embodiment. Detailed Embodiments

[0084] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings attached to this specification, for ease of understanding, the shapes, scales, aspect ratios in the vertical and horizontal directions, etc. of the components may sometimes be changed or exaggerated from the actual ones.

[0085] This means that the numerical range represented by "~" in this specification, etc. is a range that includes each of the numerical values described before and after "~" as the lower limit value and the upper limit value. In this specification, etc., terms such as "film", "sheet", "plate", etc. are only differences in names and are not concepts that are mutually distinguishable. For example, "plate" is a concept that also includes components that can usually be called "sheet" or "film".

[0086] Terms such as "parallel", "perpendicular", "identical", etc. used in this specification, etc. to define shapes or geometric conditions and their degrees, or values such as lengths, angles, etc. are not limited to strict meanings, but are interpreted to include ranges of degrees that can be expected to have the same functions.

[0087] The illumination device of the first embodiment will be described. Figure 1 It is a schematic structural diagram showing the illumination device of the first embodiment. Figure 2 It is a partially enlarged view showing the schematic structure near the first optical component in the first embodiment. Figure 3It is an explanatory diagram of a method of scanning a light beam in a pattern on the incident surface of the first projection optical system in the first embodiment. Figure 4 It is an explanatory diagram of a method of scanning a light beam in a pattern on the incident surface of the first projection optical system in the first embodiment. FIG. 5 is a distribution diagram of the light intensity within the light spot of the light beam illuminated from the second projection optical system in the first embodiment onto the illuminated area LZ.

[0088] The illumination device 1 in the first embodiment illuminates the illuminated area LZ on the irradiated surface PP with coherent light. As Figure 1 shown, the illumination device 1 includes a light source 2, a condensing optical system 3, a collimating optical system 4, a scanning unit 5, a first projection optical system 6, a first optical component 7, and a second projection optical system 8. The irradiated surface PP and the illuminated area LZ can be appropriately set according to the use of the illumination device 1. For example, when the illumination device 1 is mounted on a moving body such as a vehicle or a drone, the irradiated surface PP and the illuminated area LZ can be a road surface or the like. When the illumination device 1 is fixedly installed, the irradiated surface PP and the illuminated area LZ can also be the interior decorations such as the outer wall, roof, wall, floor of a building, or natural objects such as a cliff or a waterfall. When the illumination device 1 is used as a portable device, the irradiated surface PP and the illuminated area LZ can be appropriately selected by the user.

[0089] The light source 2 emits coherent light. The light source 2 is typically a laser light source that emits laser light. The laser light source is not particularly limited and can be various types such as a semiconductor laser.

[0090] In the illustrated example, the light beam emitted from the light source 2 becomes a light beam magnified by the condensing optical system 3. The magnified light beam is collimated by the collimating optical system 4. The light beam collimated by the collimating optical system 4 is incident on the scanning unit 5. The light beam incident on the scanning unit 5 changes its traveling direction in a specified two-dimensional direction. In Figure 1 the figure, for simplicity of illustration, it is shown that the light beam passes through the scanning unit 5. However, for example, the scanning unit 5 can have a mirror that reflects the light beam. The reflection direction of the light beam can also be periodically changed by rotating the mirror around the rotation axis. As the mirror, for example, a MEMS (Micro-Electro-Mechanical Systems) mirror or the like can be used.

[0091] The scanning frequency of the light beam based on the scanning unit 5 is not particularly limited. For example, the scanning unit 5 scans the light beam on the incident surface 6A of the first projection optical system 6. That is, through the scanning unit 5, the incident position where the light beam enters the incident surface 6A moves on the incident surface 6A. The scanning unit 5 can scan the light beam at high speed within a scanning area of a specified pattern on the incident surface 6A of the first projection optical system 6. By scanning the light beam at high speed on the incident surface 6A of the first projection optical system 6 in this way, the observer visually recognizes the afterimage of the coherent light. That is, the coherent light periodically enters each position within the scanning area, but since the period is shorter than the visual resolution, the observer feels that the coherent light continuously enters each position within the scanning area. In this way, the observer can recognize the pattern of the scanning area.

[0092] For example, in Figure 3 the example shown, the scanning unit 5 scans the light beam at high speed on the incident surface 6A of the first projection optical system 6 and within an arrow-shaped scanning area. The observer visually recognizes that light is irradiated in the pattern of an arrow in the first projection optical system 6. The observer can recognize that the pattern is displayed on the first projection optical system 6. More specifically, as Figure 4 shown, on the incident surface 6A of the first projection optical system 6, a region obtained by dividing a scanning area of a two-dimensional shape (for example, an arrow, etc.) into a plurality of regions is set. The region can be set as a rectangular region of the size of the light spot of the light beam (the region where the light beam enters at a certain moment). And, as Figure 4 shown by the solid arrows in, the light beam scans in such a way as to illuminate each region in turn. Thereby, the observer can visually recognize that an arrow pattern is displayed on the incident surface 6A of the first projection optical system 6.

[0093] In addition, as the above pattern, it is not limited to an arrow, and for example, it can also be a character, a pattern, a color pattern, a symbol, a mark, a character, a pictorial symbol, etc.

[0094] When enabling the observer to recognize the scanning area of the first projection optical system 6 as a pattern, the scanning frequency of the light beam by the scanning unit 5 is set so that the observer can observe the afterimage of the coherent light within the scanning area. This scanning frequency is preferably 15 Hz or more, and more preferably 50 Hz or more.

[0095] In the lighting device 1 of the first embodiment, it is also possible to move a scanning area of a specified pattern (for example, a scanning area having a two-dimensional shape such as an arrow) on the incident surface 6A of the first projection optical system 6. That is, it is also possible to move the scanning area on the incident surface 6A while scanning the light beam at high speed (for example, at a scanning frequency of 15 Hz or more) within the scanning area of the specified pattern. In this case, the illumination pattern on the incident surface 6A, which is visually recognized as the shape of the scanning area, moves. Regarding the movement of the pattern displayed by the first projection optical system 6, it is sufficient to set the speed to such an extent that it can be visually recognized by an observer. For example, the moving speed of the scanning area on the first projection optical system 6 at this time can be set to 140 mm / second or less.

[0096] The first projection optical system 6 adjusts the optical path of the coherent light from the scanning unit 5. As Figure 1 shown, the first projection optical system 6 has a function of converging the coherent light. As Figure 2 shown, the first projection optical system 6 converges the light beam from the scanning unit 5 to the incident surface 7A of the first optical component 7 at a first divergence angle θ1. The first projection optical system 6 can also be, for example, a lens or the like. The incident position of the light beam on the first projection optical system 6 changes according to the scanning of the light beam by the scanning unit 5. That is, the scanning unit 5 can scan the light beam within a range in which the light beam can be incident on the incident surface 6A of the lens constituting the first projection optical system 6.

[0097] As Figure 2 shown, the first divergence angle θ1 is the condensing angle of the light beam B21 incident on the incident surface 7A of the first optical component 7. Figure 2 The first divergence angle θ1 shown is determined as the maximum angle among the condensing angles. Therefore, when the shape of the light beam spot (the area where the light beam is incident at a certain moment on the plane perpendicular to the optical axis of the light beam) of the light beam from the first projection optical system 6 toward the first optical component 7 is circular, the first divergence angle θ1 can be defined as the angle when observed along the direction perpendicular to the optical path (optical axis) of the light beam. When the shape of the light beam spot is elliptical, it can be defined as the angle when observed from the direction perpendicular to the optical path (optical axis) of the light beam and perpendicular to the major axis direction of the ellipse.

[0098] Regarding the first divergence angle θ1, at at least two positions on the optical path from the first projection optical system 6 toward the first optical component 7, the width (diameter) of the light beam spot is measured using a beam analyzer, and the first divergence angle θ1 can be calculated based on the width (diameter) of the light beam spot at these at least two positions and the distance between the two measurement positions. As the beam analyzer, Ophir manufactured by Nippon Laser can be used. In addition, the width (diameter) of the light beam spot can be determined as the range of 1 / e of the maximum light intensity within the light beam spot.

[0099] The first optical component 7 diffuses the coherent light from the first projection optical system 6. As Figure 2 shown, the first optical component 7 diffuses the light beam irradiated from the first projection optical system 6 at the first divergence angle θ1 into diffused light having a second divergence angle θ2 larger than the first divergence angle θ1. The light B22 emitted from the first optical component 7 is directed toward the second projection optical system 8. The first optical component 7 is constituted by, for example, a diffractive optical element (DOE: Diffractive Optical Element) or the like. A diffractive optical element is an optical element that diffracts incident light. The diffractive optical element includes, for example, a holographic optical element (HOE: Holographic Optical Element). In addition to this, the first optical component 7 may also be constituted by a microlens array, a biconvex lens, a diffusion plate, or the like. Further, the first optical component 7 may also be constituted by a diffractive optical element combining functions of a microlens array, a biconvex lens, or the like.

[0100] The second divergence angle θ2 can be appropriately set to such an extent that even when the observer directly views the light beam irradiated from the second projection optical system 8 toward the illuminated area LZ, not all of the diffused light beam is exposed to the observer's eyes. As Figure 2 shown, the second divergence angle θ2 is the divergence angle of the light beam diffused from the emission surface 7B of the first optical component 7 and irradiated toward the second projection optical system 8. Figure 2 The second divergence angle θ2 shown is determined as the maximum angle among such divergence angles. When the shape of the light spot of the light beam from the first optical component 7 toward the second projection optical system 8 is circular, the second divergence angle θ2 can be defined as the angle when observed along the direction perpendicular to the optical path (optical axis) of the light beam. When the shape of the light spot of the light beam is elliptical, it can be defined as the angle when observed from the direction perpendicular to the optical path (optical axis) of the light beam and perpendicular to the major axis direction of the ellipse.

[0101] Regarding the second divergence angle θ2, at least two positions on the optical path from the emission surface 7B of the first optical component 7 toward the second projection optical system 8, the width (diameter) of the light spot of the light beam is measured using a beam analyzer, and the second divergence angle θ2 can be calculated based on the width (diameter) of the light spot at these at least two positions and the distance between the two measurement positions. As the beam analyzer, Ophir manufactured by Nippon Laser can be used. In addition, the width (diameter) of the light spot can be determined as the range of 1 / e of the maximum light intensity within the light spot.

[0102] The first optical component 7 can be located at the rear focal position of the first projection optical system 6. According to this configuration, the parallel light beam incident on the first projection optical system 6 converges on the first optical component 7. The first optical component 7 can be located at the front focal position of the second projection optical system 8. According to this configuration, the diverging light beam diverging from the first optical component 7 is collimated by the second projection optical system 8. According to the configuration of the first optical component 7 like this, the light beam converging and incident at the first divergence angle θ1 can be emitted at the second divergence angle θ2.

[0103] The first optical component 7 diffuses the light beam in such a manner that the irradiance [W / m 2 on the plane perpendicular to the optical axis of the light beam irradiated from the first optical component 7 to the second projection optical system 8 becomes non-discrete. Here, "non-discrete" means that the light beam diffused by the first optical component 7 at any instant does not advance by being divided into multiple beams. In other words, it means that the light beam diffused by the first optical component 7 enters a continuous angular range.

[0104] Here, Figures 5A - 5C An example of the distribution of the non-discrete irradiance [W / m 2 is shown. Figures 5A - 5C The distribution of the irradiance [W / m 2 measured in the region through which the coherent light passes on the following plane is shown: The plane is located at a position 10 cm away from the first optical component 7 and is perpendicular to the optical axis of the light beam from the first optical component 7. This distribution is the distribution of the irradiance [W / m 2 at each position arranged in one direction on this plane. In the illustrated graph and the graph assisted in Figure 10 described later, the vertical axis represents the irradiance [W / m 2 . The horizontal axis represents the distance from the reference position along one direction. Regarding the reference position, for example, the position where the irradiance [W / m 2 is 0 can be set. In addition, the irradiance can be measured using Powermax manufactured by Coherent Corporation.

[0105] Figure 5A The distribution of the non-discrete irradiance shown does not include a minimum value of the irradiance within the range (full width at half maximum) R half . The range R half is the range between two half-value positions P half on both sides of the maximum position P MAX where the maximum irradiance B MAX can be obtained, and at these two half-value positions, the irradiance is half of the maximum irradiance B MAX , which is B half . Figure 5B The distribution of the non-discrete irradiance shown is within the range Rhalf includes a minimum value. Among them, at the minimum value position P where the minimum value B can be obtained S of S the two maximum value positions P on both sides B the maximum value B of the irradiance that can be obtained at B the smaller one of the maximum values B BS and this minimum value B S the difference (B BS -B S ) with respect to the smaller one of the maximum values B BS the ratio ((B BS -B S ) / B BS ) is 50 [%] or less, more preferably 40 [%] or less, and still more preferably 30 [%] or less. And, in the example shown in Figure 5C in the range R between the two half-value positions P half shown, in the range of 50 [%] or more, the irradiance is 50 [%] or more of the maximum irradiance. More preferably, in the range of 50 [%] or more, the irradiance is 60 [%] or more of the maximum irradiance. Still more preferably, in the range of 50 [%] or more, the irradiance is 70 [%] or more of the maximum irradiance. In particular, in the irradiance distribution shown in half in the range R Figure 5C the irradiance is substantially uniform. half

[0106] In the first embodiment, the light beam from the first optical component 7 diffuses at the second divergence angle θ2 and irradiates the second projection optical system 8. However, when there is locally high-intensity light (hot spot) in the beam spot, it is not preferable in terms of laser safety. Therefore, by diffusing the coherent light in such a way that the irradiance [W / m 2 becomes non-discrete, the laser safety can be improved.

[0107] In addition, the following situation is also envisaged: the diffracted 0th-order light of the light beam whose light intensity distribution in the beam spot is not adjusted passes through the first optical component 7. Regarding this point, in the non-discrete irradiance distribution shown in Figure 5C the irradiance is substantially uniform. Therefore, even if the diffracted 0th-order light is generated in the first optical component 7, the laser safety can be improved.

[0108] In particular, in the irradiance distribution shown in Figure 5C the irradiance B at the center in the beam spot of the coherent light on the plane perpendicular to the optical axis of the coherent light irradiated from the first optical component 7 to the second projection optical system 8 C [W / m 2 ​is lower than the irradiance B at the outer peripheral edge within the beam spot. Generally, the optical path advancing at the center within the beam spot becomes the optical path of the zeroth-order light. Therefore, even if zeroth-order diffracted light is generated in the first optical component 7, laser safety can be sufficiently improved. E 2 〕. The second projection optical system 8 adjusts the optical path of the coherent light from the first optical component 7. As

[0109] shown, the second projection optical system 8 has a function of irradiating a beam that has spread and is irradiated from the first optical component 7 at a second divergence angle θ2 toward the illuminated area LZ. Figure 1 As shown, the second projection optical system 8 converges the coherent light from the first optical component 7 onto the irradiated surface PP. For example, the second projection optical system 8 converges the coherent light to a position several meters to several tens of meters away from the illumination device 1. Therefore, the width or diameter of the beam spot on the plane perpendicular to the optical axis of the coherent light emitted from the second projection optical system 8 becomes smaller as it approaches the irradiated surface PP. The second projection optical system 8 can be, for example, a lens or the like. Figure 1 As shown, the second projection optical system 8 converges the coherent light from the first optical component 7 onto the irradiated surface PP. For example, the second projection optical system 8 converges the coherent light to a position several meters to several tens of meters away from the illumination device 1. Therefore, the width or diameter of the beam spot on the plane perpendicular to the optical axis of the coherent light emitted from the second projection optical system 8 becomes smaller as it approaches the irradiated surface PP. The second projection optical system 8 can be, for example, a lens or the like.

[0110] The shape of the beam spot of the beam irradiated from the second projection optical system 8 toward the illuminated area LZ is not particularly limited. Here, the beam spot refers to the area through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light toward the illuminated area LZ. The shape of the beam spot toward the illuminated area LZ can be, for example, circular or elliptical. The diameter of the pupil of the human eye is usually about 2.5 mm to 4 mm. The diameter of the pupil in the dilated state due to disease or the like can be said to be about 6 mm to 7 mm. Therefore, from the viewpoint of laser safety, the maximum width of the beam spot toward the illuminated area LZ is preferably more than 7 mm, more preferably 10 mm or more, and further preferably 15 mm or more. In addition, as will be described later, the maximum width of the beam spot can be set to 30 mm or less. In the case where the beam spot is circular, the diameter of the beam spot can be set to the above size. In addition, in the case where the beam spot is elliptical, the length of the major axis of the beam spot can be set to the above size.

[0111] A method of illuminating the illuminated area LZ on the irradiated surface PP by the illumination device 1 described above will be described.

[0112] When using this illumination device 1, as Figure 1 ​As shown, the incident position of the coherent light on the irradiated surface PP changes according to the optical path of the coherent light determined by the scanning unit 5. More specifically, the incident position where the coherent light enters the first projection optical system 6 changes according to the optical path of the coherent light determined by the scanning unit 5. In addition, in the illustrated example, the incident angle at which the coherent light enters the first projection optical system 6 changes according to the optical path of the coherent light determined by the scanning unit 5. The incident position where the coherent light enters the first optical component 7 changes according to the incident position where the coherent light enters the first projection optical system 6. As a result, the incident position where the coherent light enters the first optical component 7 changes according to the optical path of the coherent light determined by the scanning unit 5. In the illustrated example, the incident angle at which the coherent light enters the first optical component 7 also changes according to the incident position where the coherent light enters the first projection optical system 6. Next, the emission direction of the coherent light from the second projection optical system 8 changes according to the incident position where the coherent light enters the first optical component 7. The incident position of the coherent light on the irradiated surface PP changes according to the emission direction of the coherent light from the second projection optical system 8. That is, according to this illumination device 1, by changing the optical path of the coherent light using the scanning unit 5, it is possible to change the emission direction of the coherent light from the second projection optical system 8 and move the incident position of the coherent light on the irradiated surface PP.

[0113] Therefore, when the scanning unit 5 scans the coherent light on the first optical component 7 at high speed, it is possible to move the incident position of the coherent light on the irradiated surface PP at high speed. For example, as Figure 1 shown, an illuminated area LZ with an arrow pattern is set on the irradiated surface PP. In this example, by moving the incident position of the coherent light at high speed within the illuminated area LZ, the observer visually perceives, through afterimage, that the coherent light is irradiated over the entire range of the illuminated area LZ. That is, the observer perceives that the pattern of the illuminated area LZ is displayed on the irradiated surface PP. From this perspective, the scanning frequency of the coherent light based on the scanning unit 5 is preferably above the resolution of human vision. Specifically, the scanning frequency of the coherent light can be set to 15 Hz or more, and more preferably 50 Hz or more.

[0114] By controlling the scanning of the coherent light by the scanning unit 5 as described above, it is possible to set a desired illuminated area LZ on the irradiated surface PP and illuminate the illuminated area LZ. For example, in Figure 1 the example shown, the illuminated area LZ can be only the outline of the arrow, or the illuminated area LZ can be the outline of the arrow and the area inside it.

[0115] In addition, as Figure 13A shown, it is also possible to display multiple patterns on the irradiated surface PP. In Figure 13AIn the example shown, the region with three thick arrows is the illuminated region LZ. In the illustrated example, multiple patterns are separated from each other.

[0116] Also, as Figure 13B , Figure 13C shown, it is also possible to move the illuminated region LZ on the irradiated surface PP. In Figure 13B , Figure 13C the example shown, by moving the incident position of the coherent light within the illuminated region LZ, thereby illuminating the illuminated region LZ in such a way that it is visually recognized as a prescribed pattern. In Figure 13B , Figure 13C the example shown, also in such a way that a prescribed pattern visually recognized moves on the irradiated surface PP, while maintaining the shape of the illuminated region LZ on the irradiated surface PP, the illuminated region LZ is moved. In Figure 13B the example shown, as indicated by the thin arrows, the illuminated region LZ having a pattern indicating a direction moves along a direction not parallel to the direction indicated by the pattern. In particular, in Figure 13B the example shown, the illuminated region LZ moves in a direction perpendicular to the direction indicated by the pattern. In Figure 13C the example shown, as indicated by the thin arrows, the illuminated region LZ having a pattern indicating a direction moves along the direction indicated by the pattern. In Figure 13B and Figure 13C the example shown, for the movement of the pattern displayed on the irradiated surface PP, it is sufficient to set the speed to a level that can be visually recognized by the observer. For example, the moving speed of the illuminated region LZ on the irradiated surface PP can be set to 140 mm / second or less.

[0117] However, the irradiance [W / m 2 in the plane perpendicular to the optical axis of the coherent light irradiated from the illumination device 1 to the illuminated region LZ becomes non-discrete. Therefore, the laser safety when the observer views the illumination device 1 can be effectively improved.

[0118] Here, "non-discrete" has the same meaning as that already described for the coherent light from the first optical component 7 towards the second projection optical system 8. That is, "non-discrete" means that the light beam emitted from the illumination device 1 does not split into multiple beams and advance at any instant. In other words, it means that the light beam emitted from the illumination device 1 enters a continuous angular range.

[0119] The Figures 5A - 5C already mentioned 2 is also an example of the non-discrete irradiance [W / m Figures 5A - 5C shows the irradiance [W / m 2〕 distribution, this surface is located at a position 10 cm from the light emitting surface of the illumination device 1, which is the optical component on the most downstream side of the illumination device 1, and is perpendicular to the optical axis of the light beam from the illumination device 1. This distribution is the irradiance [W / m 2 〕 distribution on this surface. The irradiance can be measured using Powermax manufactured by Coherent Corporation. Figures 5A - 5C The distribution diagram of the irradiance distribution shown is as described above.

[0120] The first optical component 7 diffuses the incident light in such a way that the irradiance distribution becomes non-discrete. Figure 1 The first optical component 7 shown has a diffraction characteristic of diffusing and transmitting while generally maintaining the optical axis. According to the combination of such a first optical component 7 and the second projection optical system 8, for the coherent light emitted from the illumination device 1 at any instant, the irradiance [W / m 2 〕 distribution can be made non-discrete. In addition, by adjusting the optical characteristics of the second projection optical system 8, for the coherent light emitted from the illumination device 1 at any instant, the irradiance [W / m 2 〕 distribution can also be made non-discrete.

[0121] As described above, from the viewpoint of laser safety, the width of the beam spot of the light beam directed toward the irradiated surface PP is preferably more than 7 mm, more preferably 10 mm or more, and still more preferably 15 mm or more. From the viewpoint of illuminating the illuminated area LZ on the irradiated surface PP with high precision, it is preferable that the width of the beam spot of the light beam directed toward the irradiated surface PP is not too large. It is preferable to set the width of the beam spot of the light beam directed toward the irradiated surface PP to 30 mm or less.

[0122] In addition, as described with reference to Figure 3 and Figure 4 it is also possible to visually recognize the scanning area on the first projection optical system 6. Moreover, by using the diffusion characteristics in the first optical component 7, for example, the diffraction characteristics of the diffractive optical element constituting the first optical component 7, corresponding or related shapes can be given to the pattern of the scanning area visually recognized on the first projection optical system 6 and the pattern of the illuminated area LZ visually recognized on the irradiated surface PP. More specifically, the same or similar shapes can be given to the scanning area on the first projection optical system 6 and the illuminated area LZ on the irradiated surface PP. In addition, in the examples shown in Figure 13B and Figure 13C it is also possible to move the pattern of the visually recognized scanning area on the first projection optical system 6.

[0123] In addition, according to the lighting device 1 of the first embodiment having the above structure, the first optical component 7 diffuses the light beam irradiated from the first projection optical system 6 at the first expansion angle θ1 and irradiates it toward the second projection optical system 8 at a second expansion angle θ2 larger than the first expansion angle θ1. Therefore, the laser safety when the observer directly views the lighting device 1 can be improved more effectively.

[0124] In addition, in the above first embodiment, as Figure 14 shown, the second projection optical system 8 may also have diffusivity. By making the second projection optical system 8 have a relatively weak diffusivity, thereby, the size of the beam spot (incident area IA) incident on the irradiated surface PP at any instant can be increased. In Figure 14 the example shown, the overall size of the beam spot of the light beam from the second projection optical system 8 toward the irradiated surface PP gradually decreases. However, the coherent light emitted from each position of the second projection optical system 8 diffuses while expanding the size of its cross-sectional area and irradiates toward the irradiated surface PP. In addition, Figure 14 the coherent light emitted from several positions of the second projection optical system 8 at a certain instant is shown.

[0125] Next, the lighting device of the second embodiment will be described. Figure 6 FIG. is a schematic structural diagram showing the lighting device of the second embodiment. And, in the lighting device of the second embodiment, the same reference numerals are given to the same structures as those in the first embodiment, and the detailed description thereof is omitted.

[0126] The lighting device 1 of the second embodiment illuminates the illuminated area LZ on the irradiated surface PP with coherent light. As Figure 6 shown, the lighting device 1 includes a light source 2, a condenser optical system 3, a collimating optical system 4, a scanning unit 5, a first projection optical system 6, a first optical component 71, a second projection optical system 81, and a second optical component 9.

[0127] The first optical component 71 diffuses the coherent light from the first projection optical system 6. The first optical component 71 can be configured in the same manner as the first optical component 7 described in the first embodiment. For example, as Figure 2As shown, the first optical component 71 has a function of diffusing the light beam irradiated from the first projection optical system 6 at the first divergence angle θ1 to a second divergence angle θ2 larger than the first divergence angle θ1. The coherent light diffused by the first optical component 71 is directed toward the second projection optical system 81. The first optical component 71 may be constituted by, for example, a diffractive optical element (DOE: Diffractive Optical Element). A diffractive optical element is an optical element that diffracts incident light. The diffractive optical element includes, for example, a holographic optical element (HOE: Holographic Optical Element). In addition to this, the first optical component 71 may be constituted by a microlens array, a biconvex lens, a diffusion plate, or the like. Further, the first optical component 71 may be constituted by a diffractive optical element assembled with functions of a microlens array, a biconvex lens, or the like.

[0128] The second projection optical system 81 adjusts the optical path of the coherent light from the first optical component 7. The second projection optical system 81 can be configured in the same manner as the second projection optical system 8 described in the first embodiment. It has a function of irradiating the light beam diffused and irradiated from the first optical component 7 at the second divergence angle θ2 toward the second optical component 9. The first optical component 71 is disposed at the front focal position of the second projection optical system 81, whereby the second projection optical system 81 functions as a collimator that makes the light beam from the first optical component 7 parallel. The second projection optical system 81 may be, for example, a Fresnel lens, a spherical lens, an aspherical lens, a lens group, an Fθ lens, an anamorphic lens, or the like. In addition to this, the second projection optical system 81 may be a concave mirror, a curved mirror, or the like. When the second projection optical system 81 is a concave mirror, the first optical component 7 may be disposed at the focal position of the concave mirror that is the second projection optical system 81. According to this configuration, the light beam reflected by the concave mirror travels in a substantially parallel direction. The parallelism of the parallel light irradiated from the second projection optical system 81 toward the second optical component 9 is preferably within ±0.2°, for example.

[0129] The second optical component 9 directs the coherent light from the second projection optical system 81 toward the illuminated area LZ on the irradiated surface PP. The illustrated second optical component 9 has the function of irradiating the light beam irradiated as parallel light from the second projection optical system 81 toward the illuminated area. The second optical component 9 may also be constituted by, for example, a diffractive optical element (DOE: Diffractive Optical Element). A diffractive optical element is an optical element that diffracts incident light. A diffractive optical element includes, for example, a holographic optical element (HOE: Holographic Optical Element). In addition to this, the second optical component 9 may also be constituted by a microlens array, a biconvex lens, a diffusion plate, etc. Further, the second optical component 9 may also be constituted by a diffractive optical element incorporating functions such as a microlens array and a biconvex lens.

[0130] The irradiance distribution related to the coherent light emitted from the lighting device 1 via the second optical component 9 is adjusted in the same manner as in the first embodiment. More specifically, in the lighting device 1 of the second embodiment, the irradiance [W / m 2 in the plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area LZ also becomes non-discrete. Therefore, the laser safety when an observer visually observes the lighting device 1 can be effectively improved.

[0131] Here, "non-discrete" has the same meaning as that described in the first embodiment. That is, "non-discrete" means that the light beam emitted from the second optical component 9 and the lighting device 1 does not split into multiple beams and travel at any instant. In other words, it means that the light beam emitted from the second optical component 9 and the lighting device 1 enters a continuous angular range.

[0132] The one already mentioned Figures 5A - 5C is also an example of the non-discrete irradiance [W / m 2 emitted from the lighting device 1 of the second embodiment. Figures 5A - 5C Shows the distribution of the irradiance [W / m 2 measured in the area through which the coherent light passes on the following plane, which is located 10 cm from the optical component on the most downstream side of the lighting device 1 and is perpendicular to the optical axis of the light beam from the lighting device 1. This distribution is the distribution of the irradiance [W / m 2 at each position arranged in one direction on this plane. The irradiance can be measured using Powermax manufactured by Coherent Corporation. Figures 5A - 5C The distribution diagram of the shown irradiance distribution is as already described.

[0133] Regarding Figures 5A - 5CThe irradiance distribution shown can be achieved by appropriately adjusting one or more of the diffraction characteristics of the first optical component 71 and the diffraction characteristics of the second optical component 9. For example, Figure 1 The first optical component 71 shown may also have diffraction characteristics that diffusely transmit while substantially maintaining the optical axis.

[0134] In addition, regarding the coherent light advancing from the second projection optical system 81 toward the second optical component 9, the irradiance [W / m 2 in the plane perpendicular to the optical axis is also preferably non-discrete. In particular, the coherent light advancing from the second projection optical system 81 toward the second optical component 9 preferably enables Figure 5C the irradiance distribution shown. In Figure 5C the irradiance distribution shown, the irradiance B C [W / m 2 at the center within the beam spot of the coherent light on the plane perpendicular to the optical axis of the coherent light irradiated from the second projection optical system 81 onto the second optical component 9 is lower than the irradiance B E [W / m 2 at the outer periphery within the beam spot. Therefore, even if the diffracted zero-order light is generated in the second optical component 9, it is possible to effectively prevent the illuminance at the center from becoming too high. As a result, laser safety can be further improved.

[0135] A method for illuminating the illuminated area LZ on the irradiated surface PP using the lighting device 1 according to the second embodiment described above will be described.

[0136] As Figure 6 shown, similar to the first embodiment, the emission direction of the coherent light from the second projection optical system 81 changes according to the incident position of the coherent light incident on the first optical component 71. And, similar to the first embodiment, the emission direction of the coherent light from the second projection optical system 81 changes according to the optical path of the coherent light determined by the scanning unit 5. Moreover, the emission direction of the coherent light from the second optical component 9 changes according to the incident direction of the coherent light from the second projection optical system 81 toward the second optical component 9. Therefore, the emission direction of the coherent light from the second optical component 9 changes according to the optical path of the coherent light determined by the scanning unit 5.

[0137] As one mode of the lighting method in the second embodiment, as Figure 15As shown, the coherent light from the second projection optical system 81 can be converged onto the irradiated surface PP by the second optical component 9. For example, the second optical component 9 converges the coherent light to a position several meters to several tens of meters away from the illumination device 1. Therefore, the width or diameter of the light spot on the plane perpendicular to the optical axis of the coherent light emitted from the second optical component 9 becomes smaller as it approaches the irradiated surface PP. According to this illumination device 1, by using the scanning unit 5 to change the optical path of the coherent light, the emission direction of the coherent light from the second optical component 9 can be changed, and the incident position of the coherent light on the irradiated surface PP can be moved.

[0138] When the scanning unit 5 scans the coherent light at high speed on the first optical component 7, the incident position of the coherent light on the irradiated surface PP can be moved at high speed. For example, as Figure 15 shown, an illuminated area LZ with an arrow pattern is set on the irradiated surface PP. In this example, the incident position of the coherent light moves at high speed within the illuminated area LZ, whereby the observer visually recognizes by afterimage that the coherent light is irradiated over the entire range of the illuminated area LZ. That is, the observer perceives that the pattern of the illuminated area LZ is displayed on the irradiated surface PP. From this point of view, the scanning frequency of the scanning unit 5 for the coherent light is preferably above the resolution of human vision. The scanning frequency of the coherent light can be set to 15 Hz or more, and more preferably 50 Hz or more.

[0139] The illumination method using the illumination device 1 of the second embodiment is the same as the illumination method using the illumination device 1 of the first embodiment described above. In the case of using the illumination device 1 of the second embodiment, the illumination described with reference to Figures 13A - 13C can also be performed. For example, it can also be that the incident position of the coherent light is moved on the irradiated surface PP so that a specified pattern recognizable by vision moves on the irradiated surface PP. In addition, similar to the second projection optical system 8 in the first embodiment, the second optical component 9 can also have a diffusion function. According to this example, as Figure 16 shown, the size of the light spot (incident area IA) incident on the irradiated surface PP at any instant can be increased. In addition, Figure 16 shows the light emitted from several positions of the second optical component 9 at a certain instant.

[0140] Also, similar to the first embodiment, the shape of the light spot of the light beam irradiated from the second optical component 9 toward the illuminated area LZ is not particularly limited. Here, the light spot refers to the area through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light toward the illuminated area LZ. The shape of the light spot toward the illuminated area LZ can be, for example, circular or elliptical. The diameter of the pupil of the human eye is usually about 2.5 mm to 4 mm. The diameter of the pupil (mydriasis) in the dilated state due to diseases or the like can be said to be about 6 mm to 7 mm. Therefore, from the viewpoint of laser safety, the maximum width of the light spot toward the illuminated area LZ is preferably more than 7 mm, more preferably 10 mm or more, and further preferably 15 mm or more. In addition, from the viewpoint of making the pattern highly accurate, the maximum width of the light spot can be set to 30 mm or less. When the light spot is circular, the diameter of the light spot can be set to the above size. In addition, when the light spot is elliptical, the length of the major axis of the light spot can be set to the above size. In addition, regarding the shape and size of the light spot of the coherent light from the second projection optical system 81 toward the second optical component 9, they can be set in the same manner as the shape and size of the light spot of the coherent light from the second optical component 9 toward the illuminated area LZ.

[0141] As another mode of the illumination method in the second embodiment, as Figure 17 shown, the second optical component 9 diffuses the coherent light from the second projection optical system 8 and expands and projects the coherent light on the irradiated surface PP having a predetermined pattern on the irradiated surface PP. The pattern projected on the irradiated surface PP is not particularly limited and can be set to any one or more of a pattern representing characters, patterns, color patterns, symbols, marks, illustrations, characters, and pictorial symbols. In this mode, by using the scanning unit 5 to change the optical path of the coherent light, as Figure 17 indicated by the thick arrow in, the incident direction of the coherent light from the second projection optical system 81 toward the second optical component 9 can be changed. By changing the incident direction of the coherent light incident on the second optical component 9, a predetermined pattern that can be visually recognized can be moved on the irradiated surface PP.

[0142] In Figure 17In the example shown, by slowly changing the emission direction of the coherent light from the second optical component 9, it is possible to visually recognize that the display pattern as the illuminated area LZ moves on the coherent light. In this illumination method, for the movement of the pattern displayed on the irradiated surface PP, it is only necessary to set the speed to a level that can be visually recognized by the observer. For example, the scanning frequency of the coherent light in the scanning unit 5 can be set to less than 15 Hz, and more preferably to 10 Hz or less. In addition, the change in the incident direction of the coherent light from the second projection optical system 81 toward the second optical component 9 can be set to 800 (° / second) or less, and more preferably to 600 (° / second) or less. Also, the moving speed of the illuminated area LZ on the irradiated surface PP can be set to 140 mm / second or less, and more preferably to 90 mm / second or less.

[0143] In Figure 18 In another example of the illumination method shown, different from Figure 17 the example shown, the emission direction of the coherent light from the second optical component 9 is changed at high speed. Moreover, a plurality of specified patterns are visually recognized on the irradiated surface PP. In Figure 18 the illumination method shown, the scanning frequency of the coherent light in the scanning unit 5 can be set to 15 Hz or more, and more preferably to 50 Hz or more. In addition, the change in the incident direction of the coherent light from the second projection optical system 81 toward the second optical component 9 can be made larger than 800 (° / second). Moreover, in Figure 18 the illumination method shown, the light source 2 can switch the emission and stop emission of the coherent light according to the operation of the scanning unit 5, or can use a shutter or the like to switch the travel and cut-off travel of the light emitted from the light source 2. That is, the coherent light is intermittently emitted from the illumination device 1. At the moment of projecting the coherent light onto the area other than the illuminated area LZ on the irradiated surface PP where the light should be irradiated, the coherent light can be made not to be emitted from the illumination device 1.

[0144] In addition, according to the illumination device 1 of the second embodiment having the above structure, the first optical component 71 diffuses the light beam irradiated from the first projection optical system 6 at the first expansion angle θ1 to the second expansion angle θ2 larger than the first expansion angle θ1 and irradiates it toward the second projection optical system 81. Therefore, it is possible to more effectively improve the laser safety when the observer directly views the illumination device 1.

[0145] The illumination device of the third embodiment will be described. Figure 7 It is a schematic structural diagram showing one mode of the illumination device of the third embodiment. Figure 8 It is a perspective view showing one mode of the schematic structure of the second optical component in the third embodiment. Figure 9 It is a perspective view showing another mode of the schematic structure of the second optical component in the third embodiment.Figure 10 It is a graph showing the irradiance distribution within the light beam spot of the light beam illuminated from the second optical component to the illuminated area when a light beam in a wavelength band different from the design wavelength of the second optical component is incident. Figure 11 It is a schematic structural diagram of another mode near the second projection optical system and the second optical component in the third embodiment. Figure 12 It is a schematic structural diagram of another mode of the illumination device in the third embodiment. Also, in the third embodiment, the same reference numerals are given to the same structures as in the first embodiment and the second embodiment, and detailed descriptions are omitted.

[0146] The illumination device 1 in the third embodiment illuminates the illuminated area LZ on the irradiated surface PP with coherent light. The illumination device 1 in the third embodiment can display a pattern corresponding to the illuminated area LZ in color. The illumination device 1 includes: a light source 2 including a first light source 21, a second light source 22, and a third light source 23; a condenser optical system 3; a collimating optical system 4; a scanning unit 5; a first projection optical system 6; a first optical component 71; a second projection optical system 81; and a second optical component 9. The second optical component 9 includes a first light source optical component 91, a second light source optical component 92, and a third light source optical component 93.

[0147] The first light source 21, the second light source 22, and the third light source 23 respectively emit coherent light in different wavelength bands. The first light source 21 emits coherent light in the red wavelength band, for example. The second light source 22 emits coherent light in the green wavelength band, for example. The third light source 23 emits coherent light in the blue wavelength band, for example. The first light source 21, the second light source 22, and the third light source 23 may also respectively emit coherent light in wavelength bands of colors other than red, green, and blue.

[0148] The first light source optical component 91 is an optical component (such as a diffractive optical element) corresponding to the coherent light in a specified wavelength band emitted from the first light source 21. The second light source optical component 92 is an optical component (such as a diffractive optical element) corresponding to the coherent light in a specified wavelength band emitted from the second light source 22. The third light source optical component 93 is an optical component (such as a diffractive optical element) corresponding to the coherent light in a specified wavelength band emitted from the third light source 23.

[0149] In Figure 7In the example shown, the second optical component 9 can select any one of the first light source optical component 91, the second light source optical component 92, and the third light source optical component 93 and arrange it on the optical path of the coherent light. In other words, the second optical component arranged at a position where it can receive the coherent light from the second projection optical system 81 can be switched between the first light source optical component 91, the second light source optical component 92, and the third light source optical component 93. The second optical component 9 can select an optical component that has an optical effect on the coherent light between the first light source optical component 91, the second light source optical component 92, and the third light source optical component 93 according to the wavelength of the coherent light emitted from the light source 2.

[0150] For example, as Figure 8 shown, the second optical component 9 has a structure in which the first light source optical component 91, the second light source optical component 92, and the third light source optical component 93 are arranged at a predetermined interval. In Figure 8 the example shown, by moving the second optical component 9, particularly by translation, an optical component corresponding to the wavelength of the coherent light can be positioned on the optical path of the coherent light. In Figure 8 the example shown, the second optical component 9 can move in the arrangement direction of the first light source optical component 91 to the third light source optical component 93.

[0151] As another example, Figure 9 the second optical component 9 shown is configured to be rotatable. In this second optical component 9, the first light source optical component 91, the second light source optical component 92, and the third light source optical component 93 are arranged in a circular shape at a predetermined interval. The second optical component 9 can rotate about the center of the circle in which the first light source optical component 91 to the third light source optical component 93 are arranged. In Figure 9 the example shown, by rotating the second optical component 9, an optical component corresponding to the wavelength of the coherent light can be positioned on the optical path of the coherent light.

[0152] In addition, in Figure 7 the example shown, the first optical component 71 adjusts the optical path of the coherent light emitted from the first light source 21, the second light source 22, and the third light source 23 included in the light source 2. The first optical component 71 is designed with diffraction characteristics corresponding to a specific wavelength band. Therefore, the diffraction efficiency of the coherent light for a wavelength band different from the designed wavelength band decreases. For the coherent light of a wavelength band different from the designed wavelength band, the diffracted zero-order light increases. For example, according to the diffraction characteristics of the first optical component 7, for the coherent light of the designed wavelength band, the irradiance distribution represented by the Figure 10 dotted line can be obtained. When the first optical component 7 having such diffraction characteristics is used for the coherent light of a wavelength band different from the designed wavelength, Figure 10The irradiance distribution represented by the solid line in Figure 1 In the irradiance distribution represented by the solid line in

[0153] Therefore, the first optical component 7 is preferably designed to obtain Figure 5C the irradiance distribution shown for the coherent light in the design wavelength band. As described above, in Figure 5C the irradiance distribution shown, the irradiance B at the center within the beam spot on the plane perpendicular to the optical axis of the coherent light irradiated from the first optical component 71 to the second projection optical system 8 C 〔W / m 2 〕is lower than the irradiance B at the outer periphery within the beam spot E 〔W / m 2 〕. Therefore, even if the diffracted zero-order light is generated in the first optical component 7, the laser safety can be sufficiently improved.

[0154] In addition, for the coherent light emitted from each of the light sources 21 to 23, it is also preferable to obtain Figure 5C the irradiance distribution shown. That is, as Figure 5C shown, the irradiance B at the center within the region through which the coherent light passes on the plane perpendicular to the optical axis of the coherent light emitted from each of the light sources 21 to 23 C 〔W / m 2 〕is preferably lower than the irradiance B at the outer periphery within the region E 〔W / m 2 〕. According to this example, the laser safety can also be improved.

[0155] In the third embodiment, the second optical component 9 is replaced, but it is not limited thereto. For example, as Figure 11 shown, an optical element 10 such as a diffraction grating may be provided between the second projection optical system 81 and the second optical component 9. The optical element 10 distributes the coherent light from each of the light sources 21, 22, 23 to the corresponding first light source optical component 91, second light source optical component 92, and third light source optical component 93. By having such a structure, it is not necessary to switch the second optical component 9 for each wavelength band of the coherent light emitted from each of the light sources 21 to 23.

[0156] In addition, in the third embodiment, the size of the scanning region of the coherent light incident on the first optical component 71 may also vary according to the wavelength band of the coherent light. Through diffraction by the first optical component 71, the larger the wavelength band of the coherent light, the wider the angle range to which it spreads. Therefore, when the size of the region incident on the first optical component 7, that is, the scanning region, is the same for the coherent light from each of the light sources 21 to 23, the angle ranges by which the coherent light from each of the light sources 21 to 23 is diffused by the first optical component 71 become different. As a result, the illuminated regions LZ on the irradiated surface PP differ between the coherent light from each of the light sources 21 to 23. Thereby, color variations may occur at the periphery of the pattern observed on the irradiated surface PP.

[0157] To address this problem, the size of the scanning region on the first optical component 71 where the coherent light is incident may be made different according to the wavelength band of the coherent light. More specifically, the size of the scanning region on the first optical component 71 where the coherent light is incident is different among a plurality of coherent lights having different wavelengths. The scanning region of the first coherent light in the first wavelength band is smaller than the scanning region of the second coherent light in the second wavelength band that is shorter than the first wavelength band. The scanning region of the first coherent light in the first wavelength band may also be included within the scanning region of the second coherent light in the second wavelength band that is shorter than the first wavelength band. That is, on the first optical component 71, the scanning region of the first coherent light may also be located inside the scanning region of the second coherent light.

[0158] And, as Figure 12 shown, the illumination device 1 of the third embodiment may include a first illumination device 11, a second illumination device 12, and a third illumination device 13. The first illumination device 11 includes a first light source 21, a condenser optical system 3, a collimating optical system 4, a scanning unit 5, a first projection optical system 6, a first optical component 71, a second projection optical system 81, and a first light source optical component 91. The second illumination device 12 includes a second light source 22, a condenser optical system 3, a collimating optical system 4, a scanning unit 5, a first projection optical system 6, a first optical component 71, a second projection optical system 81, and a second light source optical component 92. The third illumination device 13 includes a third light source 23, a condenser optical system 3, a collimating optical system 4, a scanning unit 5, a first projection optical system 6, a first optical component 71, a second projection optical system 81, and a third light source optical component 93. The first illumination device 11 to the third illumination device 13 are arranged in parallel. In Figure 12 the illumination device 1 shown, differences in the distance or direction from each of the light source optical components 91 to 93 to the irradiated region LZ may occur. The diffraction characteristics of each of the light source optical components 91 to 93 may be adjusted corresponding to this difference.

[0159] The embodiments described above are described for the purpose of easily understanding the present disclosure, and are not described for the purpose of limiting the present disclosure. Therefore, each element disclosed in the above embodiments also includes all design changes or equivalents belonging to the technical scope of the present invention.

Claims

1. A lighting device, wherein, the lighting device includes: a light source that emits coherent light; a scanning unit that scans the coherent light emitted from the light source at a scanning frequency equal to or higher than the resolution of the human vision; a first optical system that adjusts the optical path of the coherent light from the scanning unit; a first optical component that has a diffraction characteristic of diffusively transmitting while substantially maintaining the optical axis, and diffuses the coherent light from the first optical system so that the irradiance distribution becomes non-discrete; and a second optical system that adjusts the optical path of the coherent light from the first optical component, and illuminates an illuminated area on an irradiated surface with the coherent light emitted from the second optical system, the second optical system converges the coherent light from the first optical component onto the irradiated surface, the irradiance in a plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area is non-discrete, so that there is no local hot spot as high-intensity light within the beam spot of the coherent light irradiated onto the illuminated area; The unit of irradiance is W / m 2 .

2. The lighting device according to claim 1, wherein, the beam spot of the coherent light irradiated onto the illuminated area has a maximum width exceeding 7 mm.

3. The lighting device according to claim 1, wherein, the first optical component is disposed at the rear focal position of the first optical system and the front focal position of the second optical system.

4. The lighting device according to claim 1, wherein, the irradiance at the center within the beam spot of the coherent light irradiated from the first optical component onto the second optical system is lower than the irradiance at the outer periphery within the beam spot.

5. The lighting device according to claim 1, wherein, the lighting device further includes a second optical component that directs the coherent light from the second optical system toward the illuminated area on the irradiated surface.

6. The lighting device according to claim 5, wherein, the beam spot of the coherent light irradiated onto the second optical component has a maximum width exceeding 7 mm.

7. The lighting device according to claim 5 or 6, wherein, the second optical component converges the coherent light from the second optical system onto the irradiated surface.

8. The lighting device according to claim 1, wherein, the scanning frequency of the coherent light in the scanning unit is 15 Hz or higher.

9. The lighting device according to claim 1, wherein, the scanning unit scans the coherent light along a specified pattern.

10. The lighting device according to claim 1, wherein, the emission direction of the coherent light from the second optical system changes according to the optical path determined by the scanning unit, and by scanning the coherent light by the scanning unit, the incident position of the coherent light is moved within the illuminated area visually recognized as a specified pattern.

11. The lighting device according to claim 5, wherein, the emission direction of the coherent light from the second optical component changes according to the optical path determined by the scanning unit, By scanning the coherent light by the scanning unit, the incident position of the coherent light is moved within the illuminated area visually recognized as a prescribed pattern.

12. The illumination device according to claim 10 or 11, wherein the incident position of the coherent light is moved on the irradiated surface in such a manner that the prescribed pattern visually recognized moves on the irradiated surface.

13. The illumination device according to claim 5 or 6, wherein the second optical component diffuses the coherent light from the second optical system, and projects the coherent light in an expanded manner into the illuminated area having a prescribed pattern on the irradiated surface.

14. The illumination device according to claim 13, wherein the emission direction of the coherent light from the second optical component varies according to the optical path determined by the scanning unit, and by scanning the coherent light by the scanning unit, the prescribed pattern visually recognized moves on the irradiated surface.

15. The illumination device according to claim 13, wherein the emission direction of the coherent light from the second optical component varies according to the optical path determined by the scanning unit, and the coherent light is scanned by the scanning unit in such a manner that a plurality of the prescribed patterns are visually recognized on the irradiated surface.

16. The illumination device according to claim 1, wherein in the region through which the coherent light passes on a plane perpendicular to the optical axis of the coherent light from the illumination device toward the illuminated area, the distribution of the irradiance in a certain direction does not include a minimum value of the irradiance within the range between two half-value positions that can obtain half of the maximum irradiance on both sides of the maximum position where the maximum irradiance can be obtained, or if there is a minimum value of the irradiance within the range, the ratio of the difference between the smaller maximum value of the irradiance that can be obtained at two maximum value positions on both sides of the minimum value position where the minimum value can be obtained and the minimum value to the smaller maximum value is 20% or less.

17. The illumination device according to claim 1, wherein regarding the distribution of the irradiance in a certain direction in the region through which the coherent light passes on a plane perpendicular to the optical axis of the coherent light from the illumination device toward the illuminated area, in more than 70% of the range between two half-value positions that can obtain half of the maximum irradiance on both sides of the maximum position where the maximum irradiance can be obtained, the irradiance is 80% or more of the maximum irradiance.

18. The illumination device according to claim 5, wherein the light source includes a plurality of light sources that emit coherent light having different wavelengths, and the second optical component includes a plurality of second optical components corresponding to the coherent light from the plurality of light sources respectively.

19. The illumination device according to claim 1, wherein the light source includes a plurality of light sources that emit coherent light having different wavelengths, The size of the scanning area on the first optical component for the incident coherent light varies among the coherent lights from the multiple light sources.

20. An illumination method, wherein, the illumination method includes: a step of preparing an illumination device, the illumination device including: a light source that emits coherent light; a scanning unit that scans the coherent light emitted from the light source at a scanning frequency equal to or higher than the resolution of human vision; a first optical system that adjusts the optical path of the coherent light from the scanning unit; a first optical component that has a diffraction characteristic of diffusive transmission while substantially maintaining the optical axis, and diffuses the coherent light from the first optical system so that the irradiance distribution becomes non-discrete; and a second optical system that adjusts the optical path of the coherent light from the first optical component; and an illumination step of illuminating an illuminated area on an irradiated surface with the coherent light emitted from the second optical system, the second optical system converges the coherent light from the first optical component onto the irradiated surface, the irradiance in a plane perpendicular to the optical axis of the coherent light irradiated onto the illuminated area is non-discrete, so that there is no local hot spot of high-intensity light within the beam spot of the coherent light irradiated onto the illuminated area, The unit of irradiance is W / m 2 , in the illumination step, the scanning unit is used to change the optical path of the coherent light, thereby changing the emission direction of the coherent light from the second optical system and moving the incident position of the coherent light on the irradiated surface.

21. The illumination method according to claim 20, wherein, the incident position of the coherent light is moved within the illuminated area to illuminate the illuminated area in a manner that can be visually recognized as a specified pattern.

22. The illumination method according to claim 21, wherein, the incident position of the coherent light is moved on the irradiated surface in a manner that makes the specified pattern that can be visually recognized move on the irradiated surface.

23. The illumination method according to claim 20, wherein, the illumination device further has a second optical component that diffuses the coherent light from the second optical system and expands the coherent light in the illuminated area having a specified pattern on the irradiated surface, in the illumination step, the scanning unit is used to change the optical path of the coherent light, thereby moving the specified pattern that can be visually recognized on the irradiated surface.

24. The illumination method according to claim 20, wherein, the illumination device further has a second optical component that diffuses the coherent light from the second optical system and expands the coherent light in the illuminated area having a specified pattern on the irradiated surface, the coherent light is scanned by the scanning unit in a manner that multiple specified patterns can be visually recognized on the irradiated surface.

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