Lighting device

Abstract

The present application provides a kind of lighting device, wherein the laser from light emitting part (111) is shaped as parallel light via shaping optical system (112), and is irradiated to the incident surface (P2) of diffractive optical element (120) recorded with holographic image.Projection pattern (E) formed by arrow towards specified direction (D) is projected to the illumination object surface (U) on road surface as hologram reproduction image.Optical element driving part (130) makes diffractive optical element (120) rotate around rotation axis (Rx) on rotation plane (P1) perpendicular to the optical axis (C) of parallel incident light (L).Through the rotation, the geometric position relationship of diffractive optical element (120) relative to the illumination object surface (U) changes, so that the direction (D) of projection pattern (E) formed by arrow on road surface can be changed.

Description

[0001] This application is a divisional application of the original application with the application number 201780073242.5 and the filing date of 26 December 2017, and the invention name of "Illumination device". TECHNICAL FIELD

[0002] The present invention relates to an illumination device, and particularly, to an illumination device that illuminates a prescribed illumination target surface by diffracting light from a light source by a diffractive optical element. BACKGROUND

[0003] Recently, an illumination device having a function of forming a desired projection pattern on an illumination target surface using a high-luminance light source such as a laser has been put into practical use. A diffractive optical element such as a hologram has a function of diffracting incident light to be emitted in a desired direction, and thus it is possible to form a desired projection pattern on an illumination target surface as long as light from a light source is diffracted by a diffractive optical element to be emitted in a desired direction.

[0004] For example, in the following Patent Literature 1, a technology is disclosed in which an illumination device having a function of diffracting light emitted from a laser light source by a transmission-type hologram is mounted on an automobile, and a desired projection pattern composed of a hologram reproduced image is formed on a road surface. If information such as a character is recorded in advance to the hologram using this technology, it is possible to display the character as a projection pattern on a road surface.

[0005] PRIOR ART DOCUMENT

[0006] PATENT LITERATURE

[0007] Patent Literature 1 Japanese Patent Application Publication No. 2015-132707 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] As described above, the illumination device disclosed in Patent Literature 1 is able to project a desired projection pattern on an illumination target surface such as a road surface, a floor surface, or a wall surface. Here, it is determined by a designer at the time of design what kind of shape of projection pattern is projected to which position on an illumination target surface in which orientation. That is, the designer determines in advance an illumination target surface that is in a prescribed geometrical positional relationship with the illumination device, and designs the diffractive characteristics of a diffractive optical element in such a manner that a projection pattern having a prescribed shape is projected to a prescribed position on the illumination target surface in a prescribed orientation.

[0010] For example, in the case where a hologram is used as a diffractive optical element, as a hologram reconstruction image, an interference fringe is holographically recorded at a prescribed position on a prescribed illumination target surface with a prescribed orientation of a projection pattern having a prescribed shape. Therefore, as long as the hologram is not exchanged, the position and the orientation of the projection pattern projected onto the illumination target surface are fixed.

[0011] On the other hand, as a new function related to the above-described illumination device, it is preferable to be able to change the position and the orientation of the projection pattern projected onto a road surface or the like according to the situation. For example, in order to show the traveling direction of a vehicle around, in the case where a projection pattern having a shape of an arrow or the like is projected onto a road surface, it is preferable to change the position and the orientation of the arrow constituting the projection pattern according to the traveling direction of the vehicle and the environment around. However, in the conventional illumination device, it is not possible to change the projection position and the projection orientation of the projection pattern.

[0012] Therefore, an object of the present application is to provide an illumination device which is capable of projecting a desired projection pattern onto an illumination target surface of a road surface, a ground surface, a floor surface, an underwater surface, a wall surface, or the like, and is capable of changing the projection position and the projection orientation of the projection pattern.

[0013] Means for solving the problem

[0014] (1) A first aspect of the present application is an illumination device which projects a desired projection pattern onto an illumination target surface,

[0015] In the illumination device, there are provided:

[0016] a light source;

[0017] a diffractive optical element which diffracts light from the light source and projects a projection pattern onto the illumination target surface; and

[0018] an optical element driving section which supports the diffractive optical element and drives the diffractive optical element,

[0019] the optical element driving section determines a rotation axis perpendicular to a rotation plane of an incident surface including the diffractive optical element, and rotates the diffractive optical element around the rotation axis.

[0020] (2) A second aspect of the present application is the above-described first aspect of the illumination device,

[0021] the light source is provided with a light emitting section which generates a light beam and a shaping optical system which widens the light beam to generate parallel incident light, and the parallel incident light is incident on the incident surface of the diffractive optical element.

[0022] (3) A third aspect of the present application is the above-described second aspect of the illumination device,

[0023] The diffractive optical element is configured so that its incidence plane is perpendicular with respect to parallel incident light,

[0024] The optical element driving section rotates the diffractive optical element in a rotation plane including its incidence plane.

[0025] (4) A fourth aspect of the present application is a lighting device according to any one of the first to third aspects,

[0026] An XYZ three-dimensional orthogonal coordinate system having X, Y, and Z axes orthogonal to each other is defined,

[0027] The light source generates parallel incident light parallel to the X axis and causes the parallel incident light to be incident on the incidence plane of the diffractive optical element,

[0028] The diffractive optical element is composed of a hologram recording medium configured in parallel with the YZ plane, and an interference fringe for generating a reproduction image that becomes a projection pattern on an illumination target plane parallel to the XY plane is recorded in the hologram recording medium.

[0029] The optical element driving section rotates the diffractive optical element in a rotation plane parallel to the YZ plane.

[0030] (5) A fifth aspect of the present application is a lighting device according to any one of the first to fourth aspects,

[0031] A device housing that houses the light source, the diffractive optical element, and the optical element driving section and supports and fixes the light source and the optical element driving section is also provided.

[0032] (6) A sixth aspect of the present application is a lighting device that projects a desired projection pattern on an illumination target plane,

[0033] In the lighting device, there are provided:

[0034] a light source;

[0035] a diffractive optical element that diffracts light from the light source and projects a projection pattern on an illumination target plane;

[0036] an optical element driving section that supports and drives the diffractive optical element; and

[0037] a light source driving section that supports and drives the light source,

[0038] The optical element driving section changes the orientation of the incidence plane of the diffractive optical element,

[0039] The light source driving section changes the orientation of the light from the light source in accordance with the change in the orientation of the incidence plane.

[0040] (7) The seventh aspect of the present application is the illumination device according to the sixth aspect described above,

[0041] The light source driving section changes the direction of the light from the light source in such a manner that the angle formed by the optical axis of the incident light incident on the diffractive optical element and the normal line of the incident surface of the diffractive optical element is ensured to be a constant value.

[0042] (8) The eighth aspect of the present application is the illumination device according to the sixth or seventh aspect described above,

[0043] The light source is provided with a light emitting section that generates a light beam and a shaping optical system that widens the light beam to generate parallel incident light, and the parallel incident light is made incident on the incident surface of the diffractive optical element.

[0044] (9) The ninth aspect of the present application is the illumination device according to the eighth aspect described above,

[0045] The optical element driving section determines a rotation axis perpendicular to the parallel incident light and rotates the diffractive optical element around the rotation axis.

[0046] (10) The tenth aspect of the present application is the illumination device according to the sixth to ninth aspects described above,

[0047] A device housing that houses the light source, the diffractive optical element, the optical element driving section, and the light source driving section and supports and fixes the optical element driving section and the light source driving section is further provided.

[0048] (11) The eleventh aspect of the present application is the illumination device according to the sixth to tenth aspects described above,

[0049] A direction perpendicular to the illumination target surface is defined as the vertical direction,

[0050] The optical element driving section rotates the diffractive optical element in such a manner that the normal line of the incident surface of the diffractive optical element is displaced in the vertical direction.

[0051] (12) The twelfth aspect of the present application is the illumination device according to the sixth to tenth aspects described above,

[0052] An XYZ three-dimensional perpendicular coordinate system having an X axis, a Y axis, and a Z axis perpendicular to each other is defined, and a state in which the diffractive optical element is arranged in such a manner that the incident surface thereof becomes parallel to the YZ plane is defined as a reference state,

[0053] The light source generates parallel incident light parallel to the X axis in the reference state and makes the parallel incident light incident on the incident surface,

[0054] The diffractive optical element is composed of a hologram recording medium in which interference fringes for generating a reproduced image that becomes a projection pattern on an illumination target plane parallel to the XY plane are recorded,

[0055] The optical element driving section rotates the diffractive optical element around a rotation axis parallel to the Y axis.

[0056] (13) A 13th aspect of the present application is the illumination device according to the above-mentioned 12th aspect,

[0057] The light source driving section changes the direction of the light from the light source along a plane parallel to the XZ plane.

[0058] (14) A 14th aspect of the present application is the illumination device according to the above-mentioned 6th to 10th aspects,

[0059] A direction parallel to the illumination target plane is defined as a horizontal direction,

[0060] The optical element driving section rotates the diffractive optical element in such a manner that a normal line to an incident plane of the diffractive optical element standing in the horizontal direction is displaced.

[0061] (15) A 15th aspect of the present application is the illumination device according to the above-mentioned 6th to 10th aspects,

[0062] An XYZ three-dimensional perpendicular coordinate system having X, Y, and Z axes perpendicular to each other is defined, and a state in which the diffractive optical element is arranged in such a manner that an incident plane thereof becomes a direction parallel to the YZ plane is defined as a reference state,

[0063] The light source generates parallel incident light parallel to the X axis in the reference state, and makes the parallel incident light incident on the incident plane,

[0064] The diffractive optical element is composed of a hologram recording medium in which interference fringes for generating a reproduced image that becomes a projection pattern on an illumination target plane parallel to the XY plane are recorded,

[0065] The optical element driving section rotates the diffractive optical element around a rotation axis parallel to the Z axis.

[0066] (16) A 16th aspect of the present application is the illumination device according to the above-mentioned 15th aspect,

[0067] The light source driving section changes the direction of the light from the light source along a plane parallel to the XY plane.

[0068] (17) A 17th aspect of the present application is the illumination device according to the above-mentioned 6th to 10th aspects,

[0069] The optical element driving section changes the orientation of the incident surface of the diffractive optical element and determines a rotation axis perpendicular to a rotation plane including the incident surface of the diffractive optical element, and rotates the diffractive optical element around the rotation axis.

[0070] (18) The illumination device of the 18th aspect of the present application is characterized in that a desired projection pattern is projected onto an illumination target surface,

[0071] In the illumination device, there are provided:

[0072] a light source;

[0073] a diffractive optical element that diffracts light from the light source and projects a projection pattern onto an illumination target surface;

[0074] a device housing that houses the light source and the diffractive optical element; and

[0075] a device housing driving section that mounts the device housing to a prescribed mounting site and drives the device housing in a manner that changes the position or orientation of the device housing relative to the mounting site, or both.

[0076] (19) The 19th aspect of the present application is characterized in that the illumination device of the 1st to 5th, 9th, 11th to 17th aspects described above is characterized in that

[0077] the rotation axis is disposed at a position through the interior or surface of the diffractive optical element.

[0078] (20) The 20th aspect of the present application is characterized in that the illumination device of the 2nd or 8th aspect described above is characterized in that

[0079] the shaping optical system is provided with a magnifying lens that refracts the light beam generated by the light emitting section to widen it and a collimating lens that shapes the light from the magnifying lens into parallel incident light, and the parallel incident light is made to be incident on the incident surface of the diffractive optical element.

[0080] Effects of the Invention

[0081] According to the illumination device of the present application, a desired projection pattern can be projected onto an illumination target surface such as a road surface, a floor surface, a bottom surface, an underwater surface, a wall surface, and the like, and the projection position and projection orientation of the projection pattern can be changed. BRIEF DESCRIPTION OF DRAWINGS

[0082] Figure 1 is a perspective view showing the overall structure of the illumination device 100 of the 1st embodiment of the present application.

[0083] Figure 2 is Figure 1 is a plan view of the illumination device 100 shown in FIG. 1 (a view in which the illustration of some structural elements is omitted).

[0084] Figure 3 It is shown Figure 1 A front view of the diffractive optical element 120 in its rotated state.

[0085] Figure 4 It is through Figure 1 A top view illustrating the change in orientation of the projection pattern E projected by the lighting device 100 onto the surface U to be illuminated.

[0086] Figure 5 This is a perspective view showing the overall structure of the lighting device 200 according to the second embodiment of the present invention.

[0087] Figure 6 yes Figure 5 Side view of the lighting device 200 shown (illustrations of some structural components are omitted).

[0088] Figure 7 It is through Figure 5 A top view illustrating the change in position of the projection pattern of the lighting device 200 onto the surface U to be illuminated.

[0089] Figure 8 This is a perspective view showing the overall structure of the lighting device 300 according to the third embodiment of the present invention.

[0090] Figure 9 yes Figure 8 A top view of the lighting device 300 shown (some structural components are omitted).

[0091] Figure 10 It is through Figure 8 This is a top view illustrating the changes in the position and orientation of the projection pattern of the lighting device 300 onto the surface U to be illuminated.

[0092] Figure 11 This is a perspective view showing the overall structure of the lighting device 400 according to the fourth embodiment of the present invention.

[0093] Figure 12 It is through Figure 11 A top view illustrating the change in position of the projection pattern E projected by the lighting device 400 onto the surface U to be illuminated.

[0094] Figure 13 This is a block diagram showing the structure of the lighting device 500 according to the fifth embodiment of the present invention. Detailed Implementation

[0095] The present application will be described below based on several embodiments shown in the drawings. Note that in the drawings of this application, the scale of each portion, the ratio of the length to the width, and the like are changed as necessary from the actual scale in order to make the description easy to understand. Also, the terms "parallel", "perpendicular", "identical", and the like used in the description of the shape, the geometrical condition, and the like, and the values of the length, the angle, and the like are not intended to have a strict meaning, but should be interpreted within a range in which the same function can be expected.

[0096] <<1. First Embodiment>>

[0097] First, referring to Figures 1-4 , a first embodiment of the present application will be described. Figure 1 is a perspective view showing the overall structure of a lighting device 100 of the first embodiment of the present application. The lighting device 100 is a lighting device having a function of projecting a desired projection pattern E onto a prescribed illumination target surface U. The illumination target surface U is a plane forming an illuminated area illuminated by the lighting device 100, and is depicted as a rectangular area surrounded by a broken line in the drawing for ease of explanation. In the case of the example shown in the drawing, the projection pattern E is a pattern of arrow figures facing in a direction D, but the shape and size of the projection pattern E are of course not limited to the example shown in the drawing, and can have any shape. For example, a linear shape, a shape of a specific character (the same also applies to each of the embodiments described later) can also be provided.

[0098] The lighting device 100 can be installed in and used by, for example, a vehicle such as an automobile or an airplane. If the lighting device 100 is installed in and used by a vehicle, it is possible to display information such as the direction of travel of the vehicle as the projection pattern E on an illumination target surface such as a road surface, a ground surface, a floor surface, a water surface, a wall surface, and the like around the vehicle. Here, an embodiment in which the lighting device 100 is installed in an automobile and performs lighting to form a projection pattern E of arrow figures indicating the direction of travel of the automobile on a road surface in front of the automobile will be described. Therefore, in the case of the example shown in the drawing, the illumination target surface U is set on the road surface in front of the automobile.

[0099] As shown in the drawing, the lighting device 100 includes a light source 110, a diffractive optical element 120 that diffracts light L from the light source 110 and projects a projection pattern E onto an illumination target surface U (in this embodiment, a road surface in front), and an optical element driving unit 130 that supports and drives the diffractive optical element 120.

[0100] Further, although not illustrated, the illumination device 100 is also provided with a device housing 140. The device housing 140 is a housing that accommodates the light source 110, the diffractive optical element 120, and the optical element driving section 130, and in the case of the illustrated embodiment, the device housing 140 is mounted to the front end portion of the automobile. Further, the device housing 140 also functions to support and fix the light source 110 and the optical element driving section 130.

[0101] In the drawing, in order to clearly show the supporting and fixing function, the ground marks of the electrical circuit are used to indicate the respective portions of the device housing 140. Specifically, Figure 1 The ground marks 140 shown by the lines extending downward from the individual structural components 111, 112a, 112b of the light source 110 and the optical element driving section 130 and the lower ends thereof in FIG. 1 indicate that these respective structural components are supported and fixed by the device housing 140. Further, as will be described later, the diffractive optical element 120 is supported by the optical element driving section 130 in a movable state with respect to the device housing 140.

[0102] Here, as illustrated, in order to facilitate explanation, the geometric positional relationship of the respective structural components that constitute the illumination device 100 with respect to each other is defined as an XYZ three-dimensional perpendicular coordinate system. In the case of the illustrated embodiment, the illumination device 100 is mounted to the automobile in such a manner that the direction of travel becomes the positive direction of the X axis, and the illumination target surface U (the road surface in the front direction) is defined on a plane parallel to the XY plane. In order to illuminate the illumination target surface U, the light source 110 has a function of radiating light for illumination in the positive direction of the X axis.

[0103] The light source 110 has a light emitting section 111 that generates a light beam and a shaping optical system 112 that widens the light beam to generate parallel incident light L, and has a function of causing the parallel incident light L to be incident on an incident surface P2 of the diffractive optical element 120 that is disposed along a plane PI. In the case of the illustrated example, the incident region of the parallel incident light L with respect to the incident surface P2 is a circular region shown by a dashed line.

[0104] As described above, the respective components that constitute the light source 110 are fixed with respect to the device housing 140. In the case of this embodiment, a laser light emitting section is used as the light emitting section 111. The straight running property of the laser light emitted from the laser light emitting section 111 is excellent, and it is preferable as light for illuminating the illumination target surface U to form a high-definition projected pattern E.

[0105] The laser light emitted from the light emitting section 111 is shaped into parallel incident light L in the shaping optical system 112. The shaping optical system 112 is disposed at a position along the optical path from the light emitting section 111 to the diffractive optical element 120, that is, between the light emitting section 111 and the diffractive optical element 120, and shapes the laser light emitted from the light emitting section 111. Specifically, the shaping optical system 112 shapes the shape on a cross section perpendicular to the optical axis of the laser light, the shape of the solid of the laser beam, and generates the parallel incident light L.

[0106] In the case of the illustrated embodiment, the shaping optical system 112 has a magnifying lens 112a and a collimating lens 112b (both are fixed with respect to the device housing 140) disposed in this order along the optical path of the laser light. The magnifying lens 112a functions to refract the light beam generated by the light emitting section 111 to widen it, and the collimating lens 112b functions to shape the divergent light beam from the magnifying lens 112a into the parallel incident light L composed of parallel light beams. The parallel incident light L thus shaped is incident on the incident surface P2 of the diffractive optical element 120.

[0107] Finally, the laser light emitted from the light emitting section 111 is incident on the shaping optical system 112, and is first widened by the magnifying lens 112a. That is, the magnifying lens 112a diverges the laser light to transform it into a divergent light beam in a manner to widen the area occupied by the light in a cross section perpendicular to the optical axis of the laser light. Next, the divergent light beam is transformed into a parallel light beam by the collimating lens 112b. The laser light shaped by such transformation is incident on the diffractive optical element 120 as the parallel incident light L. In the case of this embodiment, the parallel incident light L becomes a parallel light beam toward the positive direction of the X axis. Here, the central axis of this parallel light beam is referred to as the optical axis C (shown by a single-dot chain line in the drawing) of the parallel incident light L (in this application, the "optical axis of the incident light incident on the diffractive optical element" refers to a direction axis along the optical path that traces the center of the region through which the light or light beam incident on the diffractive optical element passes).

[0108] Next, the diffractive optical element 120 is described. The diffractive optical element 120 has a function of diffracting the parallel incident light L from the light source 110 and projecting a desired projection pattern E on the illumination target surface U by the resulting diffracted light Ld. If the parallel incident light L (laser light) is incident on the incident surface P2 of the diffractive optical element 120 from a constant direction, the incident light can be diffracted with high efficiency in a desired direction, and the projection pattern E is formed at a prescribed position by the diffracted light Ld.

[0109] In this embodiment, the diffractive optical element 120 is composed of a holographic recording medium that records interference fringes corresponding to the center wavelength of the laser emitted from the light-emitting unit 111. Interference fringes are recorded in this holographic recording medium to generate a regenerated image as a projection pattern E (an arrow pattern pointing in the direction D) on the illuminated surface U (the road surface in front). By adjusting the pattern of the recorded interference fringes in various ways, the travel direction of the diffracted light Ld diffracted by the diffractive optical element 120, i.e., the travel direction of the light Ld diffused by the diffractive optical element 120, can be controlled, and a desired projection pattern E can be formed.

[0110] The geometrical positional relationship between the diffractive optical element 120 and the illuminated surface U is determined based on the mounting position of the device housing 140 on the vehicle and the designed position for projecting the projection pattern E. For example, if it is envisioned that the device housing 140 is mounted at a position 80 cm above the road surface with the front grille of the vehicle facing the direction of travel, and designed to project the projection pattern E onto the road surface 80 m in front of the vehicle, then the geometrical positional relationship between the diffractive optical element 120 and the illuminated surface U can be defined based on this design information. Therefore, interference fringes can be recorded in the diffractive optical element 120, and the desired projection pattern E on the illuminated surface U with such a geometrical positional relationship can serve as a regenerated image. Thus, the illuminated surface U is illuminated by diffracted light from the diffractive optical element 120, and the projection pattern E is formed on the road surface as its illumination pattern.

[0111] The diffractive optical element 120 can be fabricated, for example, by using scattered light from a real scattering plate as object light. Specifically, when an object light and a reference light, consisting of coherent light with mutual interference, are irradiated onto a holographic photosensitive material that serves as the matrix of the diffractive optical element 120, interference fringes caused by the interference of these lights are formed on the holographic photosensitive material, thereby fabricating the diffractive optical element 120. As the object light, for example, scattered light from an inexpensive isotropic scattering plate can be used, and as the reference light, a laser beam, which is coherent light, can be used.

[0112] For example, in generating a regenerated image from... Figure 1 In the case of the projection pattern E formed by the arrow pattern, an isotropic scattering plate with the shape of the arrow pattern is prepared. The light obtained when the isotropic scattering plate is irradiated with a laser is used as the object light, and a laser with the same wavelength is used as the reference light. The two are then irradiated onto the holographic photosensitive material to record interference fringes.

[0113] If the hologram recording medium in which the interference fringes are recorded as such is used as the diffractive optical element 120, and laser light is irradiated to the diffractive optical element 120 in a manner that the optical path of the reference light used at the time of recording is advanced in reverse, a reproduction image of the diffuser plate is generated at the arrangement position of the diffuser plate that is the source of the object light used when the diffractive optical element 120 is produced. If the diffuser plate that is the source of the object light used when the diffractive optical element 120 is produced has uniform surface scattering properties, the reproduction image of the diffuser plate generated by the diffractive optical element 120 also becomes a uniform surface illumination region, and the region in which the reproduction image of the diffuser plate is generated can be used as the projection pattern E.

[0114] Further, regarding the pattern of the complex interference fringes formed in the diffractive optical element 120, instead of the case where it is formed using actual object light and reference light, it can be designed by a computer in accordance with the wavelength and the incident direction of the predetermined reproduction illumination light and the shape, position, and the like of the image that should be reproduced. The diffractive optical element 120 thus obtained is generally called a computer generated hologram (CGH). For example, as shown in the example described above, in the case where the design of projecting the projection pattern E on the road surface at a position 80 m ahead of the automobile is performed, it is necessary to record using object light from a diffuser plate farther than 80 m, and the workability is extremely difficult. In such a case, it is preferable to use a computer generated hologram as the diffractive optical element 120.

[0115] In the case of using a computer generated hologram, for example, a Fourier transform hologram in which the divergence angle characteristics at each point on the diffractive optical element 120 are the same can be formed by computer synthesis. Further, an optical member such as a lens can be provided on the downstream side (the side from which the diffracted light Ld is emitted) of the diffractive optical element 120, and the total diffraction light Ld from the diffractive optical element 120 can be adjusted in a manner that illuminates the entire region of the projection pattern E.

[0116] As a specific form of the diffractive optical element 120, a volume type hologram recording medium using a photopolymer can be used, a volume type hologram recording medium of a type recorded using a photosensitive medium including a silver halide material can be used, and a relief type (embossed type) hologram recording medium can be used. As a material of the relief type hologram, resin, glass, metal, an organic-inorganic hybrid material, and the like can be used. Further, the diffractive optical element 120 can be either a transmission type or a reflection type. The illustrated embodiment is an example in which a transmission type diffractive optical element 120 is used, but in the case where a reflection type diffractive optical element 120 is used, the light source 110 needs to be arranged on the opposite side with respect to the diffractive optical element 120.

[0117] The light beam emitted from such a diffractive optical element 120 has a profile corresponding to the pattern recorded in the diffractive optical element 120. Therefore, a projected pattern E having a profile corresponding to the interference fringes recorded in the diffractive optical element 120 is formed on the illumination target surface U illuminated by such a light beam.

[0118] The present application is characterized in that such an illumination device having a function of projecting a desired projected pattern E onto a prescribed illumination target surface U is additionally provided with a function of changing the projected position and projected orientation of the projected pattern E. For example, the illustrated embodiment is an example of use mounted on an automobile, but it is more convenient if the projected position and projected orientation of the projected pattern E on the road surface can be changed in accordance with the traveling direction and the surrounding environment of the automobile. In consideration of such a case, in the illumination device 100 of the first embodiment shown, Figure 1 In the case of the illumination device 100 of the first embodiment shown, an additional function of changing the traveling direction of the light beam of the diffracted light Ld emitted from the diffractive optical element 120 is provided, and as a result, the orientation of the projected pattern E can be changed.

[0119] Specifically, the illumination device 100 has an optical element driving section 130 having a function of rotating the diffractive optical element 120 about a prescribed rotation axis Rx perpendicular to a rotation plane PI including the incident surface P2 of the diffractive optical element 120. In the case of the illustrated embodiment, the rotation plane PI is set to a plane parallel to the YZ plane, and the diffractive optical element 120 is disposed so that its incident surface (light receiving surface) P2 becomes a surface included in the rotation plane PI.

[0120] Therefore, the incident surface P2 of the diffractive optical element 120 also becomes a plane parallel to the YZ plane. On the other hand, as described above, the parallel incident light L is a parallel light beam oriented in the positive direction of the X axis, and as a result, in the case of this embodiment, the parallel incident light L becomes a parallel light beam perpendicular to the incident surface P2, and is incident from a direction perpendicular to the incident surface P2. In other words, as illustrated, in the case of erecting a normal line N to the incident surface P2, the optical axis C of the parallel incident light L is parallel to the normal line N. Also, the rotation axis Rx is parallel to the normal line N. In the illustrated embodiment, the normal line N and the rotation axis Rx are defined at the position of the optical axis C of the parallel incident light L, and therefore the optical axis C, the normal line N, and the rotation axis Rx are defined on the same axis.

[0121] As shown in the figure, the optical element drive unit 130 includes a drive mechanism 131 and a support arm 132, and functions to support the diffractive optical element 120 and to rotate the diffractive optical element 120 about the rotation axis Rx in the direction indicated by rotation direction M1. That is, the drive mechanism 131 has the function of causing the support arm 132 to oscillate about the rotation axis Rx. Such a drive mechanism 131 can be a mechanism that uses a motor and gears to rotate the diffractive optical element 120. Such a mechanism can be constructed using known mechanisms such as goniometers, and therefore detailed descriptions are omitted here.

[0122] As a result, the optical element drive unit 130 functions to rotate the diffractive optical element 120 about a predetermined rotation axis (in this example, the optical axis C of the incident light), and the diffractive optical element 120 rotates in the direction indicated by arrow M1 within the rotation plane P1 (a plane perpendicular to the optical axis C of the incident light) including the incident surface P2.

[0123] After miniaturizing the diffractive optical element 120, the rotation axis Rx is preferably parallel to the optical axis C of the incident light incident on the diffractive optical element 120, and during the rotation of the diffractive optical element 120, it is preferably determined that the incident area of ​​the light from the light source 110 remains unchanged. In other words, the optical element drive unit 130 preferably rotates the diffractive optical element 120 in such a way that the light from the light source 110 is incident on the same area of ​​the diffractive optical element 120. In the illustrated embodiment, the rotation axis Rx is aligned with the optical axis C of the parallel incident light L incident on the diffractive optical element 120. Therefore, the incident area of ​​the light in the diffractive optical element 120 does not change significantly, thus enabling the miniaturization of the diffractive optical element 120.

[0124] The diffractive optical element 120, driven by the optical element drive unit 130, causes the direction of travel of the beam composed of diffracted light Ld to change according to its rotation direction and rotation amount. Figure 2 yes Figure 1 The diagram shows a top view of the illumination device 100 (partial structural details are omitted). As shown in solid lines, the laser light emitted from the light-emitting unit 111 in the positive X-axis direction is shaped into parallel incident light L parallel to the X-axis by a shaping optical system 112 having a magnifying lens 112a and a collimating lens 112b. The optical axis C shown in solid lines corresponds to the central axis of the beam constituting the parallel incident light L. In the illustrated embodiment, this optical axis C becomes the axis passing through the center point of the plate-shaped diffractive optical element 120, and coincides with the rotation axis Rx and the normal N.

[0125] The diffractive optical element 120 shown by a solid line in the figure indicates the position of the upper end surface of the diffractive optical element 120 in the reference state. Points Ql, Q2 indicate the positions of the incident points in the reference state on the incident surface P2 of the light rays located at the outline positions of the light beams constituting the parallel incident light L. Also, in the figure, the arrows LlO, L20 shown by a solid line to the right of the diffractive optical element 120 indicate the diffracted light based on the light incident to the points Ql, Q2.

[0126] On the other hand, the diffractive optical element 120 shown by a broken line in the figure indicates the position of the upper end surface of the diffractive optical element 120 in the first rotated state. The first rotated state indicates a state in which the diffractive optical element 120 is rotated by a prescribed amount in a prescribed direction on the rotation plane PI including the incident surface P2 by driving based on the optical element driving section 130, and the positions of the points Ql, Q2 in the reference state are slightly shifted by this rotation action. In the figure, the arrows LI l, L21 shown by a broken line to the right of the diffractive optical element 120 indicate the diffracted light generated based on the light incident to the shifted points Ql, Q2. As illustrated, the diffracted light LI l, L21 in the first rotated state is directed slightly differently from the diffracted light LlO, L20 in the reference state.

[0127] Likewise, the diffractive optical element 120 shown by a one-dot chain line in the figure indicates the position of the upper end surface of the diffractive optical element 120 in the second rotated state. The second rotated state indicates a state in which the diffractive optical element 120 is rotated by a prescribed amount in a direction opposite to the above-described first rotated state on the rotation plane PI including the incident surface P2 by driving based on the optical element driving section 130, and the positions of the points Ql, Q2 in the reference state are slightly shifted by this rotation action. In the figure, the arrows L12, L22 shown by a one-dot chain line to the right of the diffractive optical element 120 indicate the diffracted light generated based on the light incident to the shifted points Ql, Q2. As illustrated, the diffracted light L12, L22 in the second rotated state is also directed slightly differently from the diffracted light LlO, L20 in the reference state.

[0128] Thus, even if the same parallel incident light L is irradiated onto the incident surface P2, when the diffractive optical element 120 is rotated around the rotation axis Rx, the direction of the diffracted light emitted from the prescribed points Ql, Q2 changes due to a change in the direction of the interference fringes formed in the vicinity of the prescribed points Ql, Q2 relative to the positions of the prescribed points Ql, Q2 of the illumination object surface U. Also, Figure 2 The diffracted light LlO to L22 shown is drawn for the purpose of facilitating the illustration of such a change in direction, and does not indicate the diffracted light used to form the projection pattern E composed of the arrow patterns shown. Figure 1 The diffracted light used to form the projection pattern E composed of the arrow patterns shown.

[0129] Figure 3 is a diagram showingFigure 1 The diagram shows a front view of the diffractive optical element 120 in its rotated state. As described above, the drive mechanism 131 drives the support arm 132 to rotate the incident surface P2 of the diffractive optical element 120 about the rotation axis Rx within a rotation plane P1 including the incident surface P2. As a result, the diffractive optical element 120 rotates in the rotation direction indicated by arrow M1. Here, solid lines represent the positions of the diffractive optical element 120 and the support arm 132 in the reference state, dashed lines represent the positions of the diffractive optical element 120 and the support arm 132 in the first rotation state, and single-dotted lines represent the positions of the diffractive optical element 120 and the support arm 132 in the second rotation state.

[0130] In this way, the drive mechanism 131 can rotate the diffractive optical element 120 in any direction by any amount and stop the rotation at any position, thereby bringing the diffractive optical element 120 to rest in any rotational state. As described above, when the diffractive optical element 120 is rotated in this way, the orientation of the diffracted light generated from each part of the diffractive optical element 120 changes, and as a result, the orientation of the projection pattern E formed on the illumination object surface U can be changed.

[0131] Figure 4 It is through Figure 1 This is a top view illustrating the change in orientation of the projection pattern E projected onto the illuminated object surface U by the lighting device 100. In the figure, projection pattern E10, shown by a solid line, represents the pattern projected in the reference state; projection pattern E11, shown by a dashed line, represents the pattern projected in the first rotational state; and projection pattern E12, shown by a single-dot-dash line, represents the pattern projected in the second rotational state. Projection pattern E10 is an arrowhead pattern pointing towards the reference direction D10, but projection pattern D11 becomes an arrowhead pattern pointing towards the first rotational direction D11, and projection pattern D12 becomes an arrowhead pattern pointing towards the second rotational direction D12.

[0132] At this time, the distribution, particularly the profile, of the light beam diffracted by the diffractive optical element 120 is not substantially changed even if the diffractive optical element 120 is rotated. That is, the light beam diffracted by the rotated diffractive optical element 120 constitutes a light beam obtained by rotating the light beam diffracted by the diffractive optical element 120 in the reference state in a rotational direction and by a rotational amount corresponding to the rotational direction and the rotational amount of the diffractive optical element 120, and thus the orientation of the projection pattern E projected onto the illumination target surface U is changed. However, the shape of the projection pattern E is substantially maintained, and thus in the case of the projection pattern E using an arrow pattern as in the illustrated embodiment, the orientation of the arrow pattern projected onto the illumination target surface U is changed by the driving operation of the optical element driving unit 130. In this way, in the case of the illustrated embodiment, the orientation of the projection pattern E of the arrow pattern can be changed by the optical element driving unit 130 in accordance with the rotational direction and the rotational amount of the diffractive optical element 120.

[0133] In addition, in the case of the first embodiment, the diffractive optical element 120 is rotated with the rotational axis Rx as the center axis, and thus as illustrated, even if the diffractive optical element 120 is rotated, the position of the projection pattern E obtained on the illumination target surface U is substantially maintained to be the same, and only the orientation is changed. Figure 4

[0134] In the case of the illustrated example, in the reference state, the projection pattern E10 (solid line) oriented in the reference direction D10 is formed, but in the first rotated state, the projection pattern E11 (dotted line) oriented in the direction D11 rotated by an angle +θ1 (in the present application, the clockwise direction is set as a positive angle) with respect to the reference direction D10 is formed, and in the second rotated state, the projection pattern E12 (one-dot chain line) oriented in the direction D12 rotated by an angle -θ2 with respect to the reference direction D10 is formed. As a result, the projection pattern E can be rotated in the rotational direction indicated by the arrow M2 while maintaining the projection position of the projection pattern E projected onto the illumination target surface U to be substantially the same. As illustrated, the rotational direction and the rotational angles +θ1, -θ2 of the projection pattern E can be controlled by the rotational direction and the rotational angles of the diffractive optical element 120. Figure 3

[0135] As described above, in the case where the illumination device 100 is installed in a car and used, the projection patterns E10, E11, E12 as illustrated can be selectively displayed on the road surface in front of the traveling direction, and thus for example, the use of reporting the traveling direction of the car to a pedestrian can be used. That is, the projection pattern E10 can be displayed on the road surface in the case where the car is traveling straight, the projection pattern E11 can be displayed on the road surface in the case where the car is making a right turn, and the projection pattern E12 can be displayed on the road surface in the case where the car is making a left turn. Figure 4 ​​​

[0136] In particular, Figure 1 In the illumination device 100 of the illustrated embodiment, the diffractive optical element 120 is configured such that its incident surface P2 is perpendicular to the parallel incident light L, and the optical element drive unit 130 rotates the diffractive optical element 120 on a rotation plane P1 including the incident surface P2. More specifically, when describing the device using an XYZ three-dimensional vertical coordinate system having mutually perpendicular X, Y, and Z axes, the light source 110 generates parallel incident light L parallel to the X-axis, which is incident on the incident surface P2 of the diffractive optical element 120. Furthermore, the diffractive optical element 120 is constructed from a holographic recording medium arranged parallel to the YZ plane, in which interference fringes are recorded for generating a regenerated image as a projection pattern E on the illumination target surface U parallel to the XY plane. Moreover, the optical element drive unit 130 rotates the diffractive optical element 120 on a rotation plane P1 parallel to the YZ plane.

[0137] By employing this structure, a desired projection pattern E can be projected onto the illuminated surface U, such as a road surface, ground surface, bottom surface, underwater surface, or wall surface. Furthermore, the projection position and orientation can be changed while generally maintaining the shape of the projection pattern E. Moreover, a clear holographic reconstructed image can be obtained as the projection pattern E, and the size of the diffractive optical element 120 can be minimized to the required minimum.

[0138] in addition, Figure 1 The illustrated embodiment shows a case where the diffractive optical element 120 rotates relative to the device housing 140 mounted on the vehicle, while the light source 110 remains fixed. However, a structure in which the light source 110 rotates in response to the rotation of the diffractive optical element 120 can also be used. In this case, during the rotation of the diffractive optical element 120, the geometrical positional relationship between the light source 110 and the diffractive optical element 120 remains constant, and the incident area of ​​light on the incident surface P2 does not change. Therefore, even if an element with an arbitrary shape of incident surface P2 is used as the diffractive optical element 120, the incident range of the incident light will not deviate from the incident surface P2. Thus, the amount of rotation of the diffractive optical element 120 can be increased, further increasing the change in the orientation of the projected pattern E. Furthermore, even during the rotation, the incident range of the incident light will not deviate from the incident surface P2, thus the incident surface P2 can be suppressed to the minimum required area, and the diffractive optical element 120 can be miniaturized.

[0139] Further, in the illumination device 100 of the above-described embodiment, the light source 110 has the light emitting portion 111, the expansion lens 112a, and the collimating lens 112b, and the collimating lens 112b is disposed between the light emitting portion 111 and the diffractive optical element 120 along the optical path from the light emitting portion 111 to the diffractive optical element 120. Thus, the light beam emitted from the light emitting portion 111 and widened by the expansion lens 112a is parallelized by the collimating lens 112b. The parallelized light beam is easy to handle, and thus can be utilized in a wider range of fields. For example, it is suitable for use in an application in which the optical path is finally adjusted using a hologram. As in the above-described embodiment, when the diffractive optical element 120 is composed of a hologram recording medium and a parallel light beam is used as the incident light thereon, the diffractive optical element 120 becomes easy and inexpensive to manufacture, and the diffraction efficiency can be improved.

[0140] << §2. Second Embodiment >>

[0141] Next, the second embodiment of the present application will be described with reference to Figures 5-7 The second embodiment of the present application will be described. Figure 5 is a perspective view showing the overall structure of an illumination device 200 of the second embodiment of the present application. The illumination device 200, like the above-described illumination device 100, is an illumination device having a function of projecting a desired projection pattern E onto a prescribed illumination target surface U, and has a similar structure to the illumination device 100. Therefore, an embodiment in which the illumination device 200 is installed in an automobile and projects a projection pattern E composed of an arrow pattern indicating the traveling direction of the automobile onto the road surface in front of the automobile will be described here. Therefore, in the following description, the illumination target surface U is set to the position on the road surface in front of the automobile, and the projection pattern E composed of the arrow pattern in the direction D is projected onto the illumination target surface U. Figure 5

[0142] As illustrated, the illumination device 200, like the above-described illumination device 100, is provided with a light source 210, a diffractive optical element 220 that diffracts the light L from the light source 210 to project a projection pattern E onto an illumination target surface U (in this embodiment, onto the road surface in front of the automobile), an optical element driving portion 230 that supports and drives the diffractive optical element 220, and a device housing 240 (omitted from the illustration) that houses them. The illumination device 200 of the second embodiment is characterized in that a light source driving portion 250 is further added. The light source driving portion 250 has a function of supporting and driving the light source 210.

[0143] ​Although not illustrated, the illumination device 200 is provided with a device housing 240. The device housing 240 is a housing that accommodates the light source 210, the diffractive optical element 220, the optical element driving section 230, and the light source driving section 250, and in the case of the embodiment shown here, the device housing 240 is mounted to the front end portion of the automobile. The device housing 240 also functions to support and fix the optical element driving section 230 and the light source driving section 250.

[0144] In the Figure 5 , in order to clearly show the state of support and fixation of each structural member, a ground symbol of an electric circuit is used to indicate each portion of the device housing 240. Specifically, Figure 5 the ground symbol 240 shown at the lower end of the line extending downward from the optical element driving section 230 and the light source driving section 250 in the

[0145] Likewise, the light source 210 is supported in a movable state with respect to the device housing 240 by the light source driving section 250. Here, the magnification lens 212a and the collimator lens 212b (shaping optical system 212), which are separate structural members of the light source 210, are fixed to the light emitting section 211 and move together when the light emitting section 211 moves. Figure 5 the ground symbol 211 shown at the left end of the broken line extending downward from the magnification lens 212a and the collimator lens 212b in the

[0146] In the Figure 5 , in order to facilitate explanation, an XYZ three-dimensional orthogonal coordinate system is defined with respect to the geometric positional relationship of each structural member constituting the illumination device 200 to each other. The illumination device 200 is mounted to the automobile in such a manner that the direction of travel becomes the positive direction of the X axis, and the illumination target surface U (the road surface in front) is defined on a plane parallel to the XY plane. In order to illuminate the illumination target surface U, the light source 210 has a function of irradiating light for illumination in the positive direction of the X axis in the reference state shown in the drawing. However, as will be described later, the orientation of the light source 210 can be changed by the light source driving section 250.

[0147] Figure 5 The functions of the light source 210 and the diffractive optical element 220 in the reference state shown in the Figure 1The light source 110 and the diffractive optical element 120 in the first embodiment shown have the same functions. The light source 210 has a light emitting section 211 that generates a laser beam and a shaping optical system 212 that widens the laser beam to generate parallel incident light L, and the shaping optical system 212 has a magnifying lens 212a and a collimator lens 212b. The parallel incident light L shaped by the shaping optical system 212 is incident on an incident plane P2 of the diffractive optical element 220. In the case of the example shown, the incident region of the parallel incident light L with respect to the incident plane P2 is a circular region shown by a dotted line.

[0148] The diffractive optical element 220 has a function of diffracting the parallel incident light L from the light source 210 and projecting a desired projection pattern E on the illumination target plane U by the resulting diffracted light Ld. In the case of this embodiment, the diffractive optical element 220 is composed of a hologram recording medium in which interference fringes corresponding to the center wavelength of the laser light emitted from the light emitting section 211 are recorded, and in which interference fringes for generating a reproduced image that becomes the projection pattern E on the illumination target plane U are recorded. As described above, this diffractive optical element 220 can be produced using object light and reference light from a scattering plate of a real object, or can be produced using a method of computer-synthesizing a hologram. Figure 1 The diffractive optical element 120 shown is also composed of a hologram recording medium in which interference fringes corresponding to the center wavelength of the laser light emitted from the light emitting section 211 are recorded, and in which interference fringes for generating a reproduced image that becomes the projection pattern E on the illumination target plane U are recorded. As described above, this diffractive optical element 220 can be produced using object light and reference light from a scattering plate of a real object, or can be produced using a method of computer-synthesizing a hologram.

[0149] Thus, Figure 5 The light source 210 and the diffractive optical element 220 shown have the same functions as Figure 1 The light source 110 and the diffractive optical element 120 shown have the same functions, and detailed descriptions thereof are omitted.

[0150] On the other hand, the optical element driving section 230 and the light source driving section 250 used in the illumination device 200 of this second embodiment perform an operation for changing the position of the projection pattern E formed on the illumination target plane U. In the case of the embodiment shown, the projection pattern E is composed of an arrow pattern in the direction D, but by performing the driving operation described below, it is possible to move this projection pattern E in the X-axis direction.

[0151] Figure 1 The optical element driving section 130 shown has a function of rotating the diffractive optical element 120 about a rotation axis Rx that is perpendicular to the rotation plane PI, Figure 5 The optical element driving section 230 shown has a function of rotating the diffractive optical element 220 about a rotation axis Ry that passes through the center point in the diffractive optical element 220 and is parallel to the Y-axis. In the case of this embodiment, the rotation axis Ry becomes an axis that passes through the center position in the thickness direction of the diffractive optical element 220.

[0152] Figure 5When the diffractive optical element 220 is in the reference state, the incident surface P2 and the emergent surface P3 of the diffractive optical element 220 are both maintained in a posture parallel to the YZ plane. On the other hand, the parallel incident light L is a parallel light beam toward the positive direction of the X axis, and thus in the illustrated reference state, the parallel incident light L becomes a parallel light beam perpendicular to the incident surface P2, and is incident from a direction perpendicular to the incident surface P2. Therefore, the optical element driving section 230 rotates the diffractive optical element 220 about the rotation axis Ry perpendicular to the parallel incident light L.

[0153] Here, as illustrated, in the reference state, when a normal line N20 is erected with respect to the incident surface P2, the optical axis C of the parallel incident light L is parallel with respect to the normal line N20. On the other hand, the illustrated normal line N21 indicates a normal line erected with respect to the incident surface P2 when the diffractive optical element 220 is rotated about the rotation axis Ry to form the first rotated state, and the illustrated normal line N22 indicates a normal line erected with respect to the incident surface P2 when the diffractive optical element 220 is reversely rotated about the rotation axis Ry to form the second rotated state. In the case of the illustrated example, the normal line N21 becomes a normal line obtained by inclining the normal line N20 downward, and the normal line N22 becomes a normal line obtained by inclining the normal line N20 upward. Therefore, the diffractive optical element 220 is rotated in the longitudinal direction indicated by the arrow M3 about the rotation axis Ry as a central axis.

[0154] As illustrated, the optical element driving section 230 has a driving mechanism 231 and a support arm 232 in order to change the orientation of the incident surface P2 of the diffractive optical element 220 to the longitudinal direction, and has a function of supporting the diffractive optical element 220 and rotating the diffractive optical element 220 about the rotation axis Ry in the direction indicated by the arrow M3. That is, the driving mechanism 231 has a function of oscillating the support arm 232 about the rotation axis Ry. Such a driving mechanism 231 can be configured using a publicly known mechanism, and thus detailed description thereof is omitted here.

[0155] In the illumination device 200 of this second embodiment, the operation of driving the diffractive optical element 220 by the optical element driving section 230 is performed, and at the same time, the operation of driving the light source 210 by the light source driving section 250 is also performed. That is, the light source driving section 250 performs a driving operation of changing the orientation of the light source 210 to the longitudinal direction in order to change the orientation of the light L from the light source 210 in accordance with the change in the orientation of the incident surface P2 of the diffractive optical element 220.

[0156] As shown in the figure, the light source driving section 250 has a driving mechanism 251 and a support arm 252 in order to change the orientation of the light source 210 to the longitudinal direction, and has a function of supporting the light source 210 and rotating the light source 210 in the direction indicated by the arrow M4. Such a driving mechanism 251 can also be configured using a publicly known mechanism, and thus detailed description thereof is omitted here.

[0157] Further, it is desirable that the driving action of the light source driving section 250 is preferably an action of rotating the light source 210 around the rotation axis Ry parallel to the Y axis. In this case, the light source 210 and the diffractive optical element 220 are rotated around the rotation axis Ry as a unit, and thus the relative positional relationship between these devices and the device housing 240 can be changed while maintaining the relative positional relationship between the light source 210 and the diffractive optical element 220 constant.

[0158] In other words, if the above-described ideal driving method is employed, the light source driving section 250 changes the orientation of the light L from the light source 210 in such a manner that the optical axis C of the incident light incident on the diffractive optical element 220 and the normal line N20 of the incident surface P2 of the diffractive optical element 220, which is erected, maintain a constant angle (0° in the case of the illustrated example), and thus the geometric position of the incident light (parallel incident light L) with respect to the diffractive optical element 220 is always maintained constant, and a part of the cross section of the parallel incident light L does not protrude to the outside of the incident surface P2 of the diffractive optical element 220.

[0159] However, in terms of practicality, even if the rotation axis of the light source 210 and the rotation axis Ry of the diffractive optical element 220 are not completely identical, no major problem occurs. For example, as the rotation axis of the light source 210, an axis parallel to the Y axis disposed closer to the light source 210 than the rotation axis Ry can be set. In this case, when the rotation axis of the light source 210 and the rotation axis Ry of the diffractive optical element 220 are not identical, the relative positional relationship between the light source 210 and the diffractive optical element 220 is not maintained constant, and thus a part of the cross section of the parallel incident light L can protrude to the outside of the incident surface P2 of the diffractive optical element 220, but even if such protrusion occurs, only the amount of light for illumination slightly decreases, and thus no major problem occurs (preferably, the protruding portion is cut off by an aperture). Of course, in order to prevent such protrusion, the size of the diffractive optical element 220 can be designed to be slightly larger.

[0160] Even if such an ideal driving method is not employed, no major problem occurs in terms of practicality, and if the light source 210 is rotated around a rotation axis disposed closer than the rotation axis Ry, the displacement range of the light source 210 can be suppressed to be small, and the device can be further miniaturized.

[0161] Thus, if the orientation of the incident surface P2 of the diffractive optical element 220 is changed by the optical element driving unit 230, and the orientation of the light L from the light source 210 is changed by the light source driving unit 250 according to this change in orientation—that is, when the direction perpendicular to the illuminated object surface U is called the vertical direction, if the deflection angle of the vertical direction of the normal N20 is correlated with the deflection angle of the vertical direction of the light L, the beam composed of the diffracted light Ld emitted from the exit surface P3 of the diffractive optical element 220 will change its direction of travel. As a result, the position of the projected pattern E formed on the illuminated object surface U also changes. The driving mechanisms 231 and 251 can rotate the diffractive optical element 220 and the light source 210 in any direction by any amount, and by stopping this rotation at any position, the diffractive optical element 220 and the light source 210 can be made stationary in any rotational state. Therefore, the projected pattern E can be displayed at the desired position.

[0162] Figure 6 yes Figure 5 The diagram shows a side view of the lighting device 200 (some structural components are omitted). Solid lines in the diagram indicate... Figure 5 The diagram shows the positions of various structural components and the laser beam path in the reference state (the state in which the incident surface P2 and the exit surface P3 of the diffractive optical element 220 are parallel to the YZ plane). Specifically, the light-emitting part 211, shown in solid lines, emits laser light in the positive X-axis direction. This laser light is shaped into a parallel incident beam L parallel to the X-axis by the magnifying lens 212a and the collimating lens 212b. The optical axis C, shown in solid lines in the diagram, corresponds to the central axis of the beam constituting this parallel incident beam L. In the illustrated embodiment, this optical axis C becomes the axis passing through the center point of the plate-shaped diffractive optical element 220.

[0163] The diffractive optical element 220, shown by solid lines in the figure, represents the position of the diffractive optical element 220 in the reference state as viewed from the side. The parallel incident light L, shown by solid lines, incident on the incident surface P2 from the left side of the figure, is diffracted as the diffracted light Ld, shown by solid lines, from the exit surface P3, and illuminates the object surface U (a plane parallel to the XY plane). The figure shows an example of the range where the diffracted light Ld (solid lines), based on the parallel incident light L (solid lines) incident on the diffractive optical element 220, reaches the projection points Q11 to Q12 on the object surface U.

[0164] The diffractive optical element 220 is a holographic recording medium. Therefore, in principle, the diffracted light incident on any point on the diffractive optical element 220 will all reach the range shown by the projection points Q11 to Q12, forming a projection pattern E. The projection pattern E formed on the illumination object surface U is as follows: Figure 5In the case of the arrow pattern shown, the projection point Q11 becomes the root end portion of the arrow pattern (the end on the front side when viewed from the illumination device 200), and the projection point Q12 becomes the front end portion of the arrow pattern (the end on the back side when viewed from the illumination device 200).

[0165] On the other hand, the dotted lines in the figure show the positions of the respective structural components and the optical path of the laser light in the first rotational state (the state in which the incident face P2 and the emergent face P3 of the diffractive optical element 220 are rotated from the reference state with the rotational axis Ry as the center axis, in the counterclockwise direction in the figure). Figure 6 Here, an example in which the ideal driving operation described above is performed, and both the light source 210 and the diffractive optical element 220 are rotated around the rotational axis Ry, is shown. Therefore, the angle formed by the optical axis C of the incident light and the normal line of the incident face P2 of the diffractive optical element 220 (0° in the example shown in the figure) is always constant, and diffraction is performed on the diffractive optical element 220 in the optimum condition.

[0166] However, the relative position of the diffractive optical element 220 with respect to the illumination target face U changes, and therefore the parallel incident light L shown by the dotted lines, which is incident to the incident face P2 from the left side of the figure, is irradiated onto the illumination target face U as the diffracted light Ld shown by the dotted lines from the emergent face P3. As a result, the diffracted light Ld (dotted lines) based on the parallel incident light L (dotted lines) that is incident to the diffractive optical element 220 reaches the range shown by the projection points Q21 to Q22 on the illumination target face U. In the case of the arrow pattern shown as the projection pattern E formed on the illumination target face U, the projection point Q21 becomes the root end portion of the arrow pattern, and the projection point Q22 becomes the front end portion of the arrow pattern. Figure 5 In the case of the arrow pattern shown, the projection point Q11 becomes the root end portion of the arrow pattern (the end on the front side when viewed from the illumination device 200), and the projection point Q12 becomes the front end portion of the arrow pattern (the end on the back side when viewed from the illumination device 200).

[0167] Also, the single-dot chain lines in the figure show the positions of the respective structural components and the optical path of the laser light in the second rotational state (the state in which the incident face P2 and the emergent face P3 of the diffractive optical element 220 are rotated from the reference state with the rotational axis Ry as the center axis, in the clockwise direction in the figure). Figure 6 Here, an example in which the ideal driving operation described above is performed, and both the light source 210 and the diffractive optical element 220 are rotated around the rotational axis Ry, is shown. Therefore, the angle formed by the optical axis C of the incident light and the normal line of the incident face P2 of the diffractive optical element 220 (0° in the example shown in the figure) is always constant, and diffraction is performed on the diffractive optical element 220 in the optimum condition.

[0168] However, the relative position of the diffractive optical element 220 with respect to the illumination target surface U is changed, and thus the parallel incident light L shown by a single-dot chain line incident from the left side of the drawing to the incident surface P2 is irradiated as the diffracted light Ld shown by a single-dot chain line from the emergent surface P3 to the illumination target surface U. As a result, the diffracted light Ld (single-dot chain line) based on the parallel incident light L (single-dot chain line) incident to the diffractive optical element 220 reaches the range shown by the projection points Q31 to Q32 on the illumination target surface U. In the case where the projection pattern E formed on the illumination target surface U is an arrow pattern as shown by Figure 5 the projection point Q31 is the root end of the arrow pattern, and the projection point Q32 is the front end of the arrow pattern.

[0169] Figure 7 is a plan view for explaining the change in the position of the projection pattern projected onto the illumination target surface U by the illumination device 200 shown by Figure 5 The projection pattern E20 shown by a solid line in the drawing indicates a pattern projected in a reference state, the projection pattern E21 shown by a broken line indicates a pattern projected in a first rotated state, and the projection pattern E22 shown by a single-dot chain line indicates a pattern projected in a second rotated state. Any of the projection patterns is a pattern of an arrow pattern facing the right direction (positive direction of the X axis) of the drawing, but the projection pattern E21 is shifted by a displacement amount el in the right direction compared with the position of the projection pattern E20, and the projection pattern E22 is shifted by a displacement amount e2 in the left direction.

[0170] At this time, regarding the distribution of the light beams diffracted by the diffractive optical element 220, particularly the profile, even if the diffractive optical element 220 is rotated, it is not substantially changed, and the shape of the projection pattern E is substantially maintained. In the case where the projection pattern E employing an arrow pattern as in the illustrated embodiment, the position of the arrow pattern projected onto the illumination target surface U is changed by the driving operation based on the optical element driving section 230 and the light source driving section 250. In this way, in the case of the illustrated embodiment, the position related to the X axis direction of the projection pattern E of the arrow pattern can be changed by the optical element driving section 230 and the light source driving section 250 according to the rotation direction and the rotation amount of the light source 210 and the diffractive optical element 220, and the projection pattern E can be moved along the displacement direction M5 parallel to the X axis. In addition, in the case of the illustrated embodiment, the orientation of the projection pattern E obtained on the illumination target surface U is not changed but maintained as it is. Figure 5

[0171] In summary, in the illumination device 200 of the second embodiment described herein, the direction perpendicular to the illumination target surface U (the direction of the Y axis in the drawing) is set as the displacement direction M5 of the projection pattern E of the arrow pattern, and the position of the arrow pattern in the X axis direction is changed by the driving operation based on the optical element driving section 230 and the light source driving section 250. Figure 5 ​In the example case, the Z-axis direction is defined as the vertical direction. The optical element drive unit 230 rotates the diffractive optical element 220 so that the normal N20 standing on its incident surface P2 is displaced in the vertical direction. The light source drive unit 250 can change the orientation of the light L from the light source 210 according to the change in the orientation of the diffractive optical element 220.

[0172] The rotation axis does not necessarily have to be parallel to the Y-axis, but for practical purposes, it is preferable to be such an axis. Figure 5 The illumination device 200 shown is configured such that a rotation axis Ry is set parallel to the Y-axis. This allows for efficient diffraction via the diffractive optical element 220, such as... Figure 7 The example shown allows the projected pattern E to move along a displacement direction M5 parallel to the X-axis, and the device can be easily designed.

[0173] As a result, in adopting Figure 5 In the illustrated embodiment, when defining a three-dimensional vertical coordinate system XYZ with mutually perpendicular X, Y, and Z axes, and defining a state in which the incident surface P2 of the diffractive optical element 220 is arranged in an orientation parallel to the YZ plane as a reference state, the light source 210 generates parallel incident light L parallel to the X-axis in this reference state, and the parallel incident light L is incident on the incident surface P2. Furthermore, the diffractive optical element 220 is constructed from a holographic recording medium, in which interference fringes are recorded to generate a regenerated image as a projection pattern E on the illumination target surface U parallel to the XY plane. The optical element drive unit 230 rotates the diffractive optical element 220 about a rotation axis Ry parallel to the Y-axis, and the light source drive unit 250 changes the orientation of the light L from the light source 210 along a plane parallel to the XZ plane according to the change in the orientation of the diffractive optical element 220.

[0174] By adopting such a structure, a desired projection pattern E can be projected onto the lighting target surface U such as road surface, ground surface, bottom surface, underwater surface, wall surface, etc., and the projection position can be changed while generally maintaining the shape of the projection pattern E.

[0175] <<<§3. Third Implementation Method>>>

[0176] Next, refer to Figures 8-10 The third embodiment of the present invention will now be described. Figure 8is a perspective view showing the overall structure of a lighting device 300 according to a third embodiment of the present application. The lighting device 300 is, like the lighting devices 100 and 200 described above, a lighting device having a function of projecting a desired projection pattern E onto a prescribed illumination target surface U, and has a similar structure to the lighting devices 100 and 200. Therefore, an embodiment in which the lighting device 300 is installed in a vehicle and projects a projection pattern E composed of arrow graphics indicating the direction of travel onto the road surface in front of the vehicle will be described here. Therefore, in Figure 8 the illumination target surface U is set to a position on the road surface in front of the vehicle, and the projection pattern E composed of arrow graphics in the direction D is projected onto the illumination target surface U.

[0177] As shown in the figure, the lighting device 300, like the lighting device 200 described above, is provided with a light source 310, a diffractive optical element 320 that diffracts light L from the light source 310 to project a projection pattern E onto an illumination target surface U (in this embodiment, the road surface in front of the vehicle), an optical element drive section 330 that supports and drives the diffractive optical element 320, a light source drive section 350 that supports and drives the light source 310, and a device housing 340 (omitted from the figure) that houses them.

[0178] The device housing 340 is a housing that houses the light source 310, the diffractive optical element 320, the optical element drive section 330, and the light source drive section 350, and in the case of the embodiment shown here, the device housing 340 is installed in the front end portion of the vehicle. The device housing 340 also functions to support and fix the optical element drive section 330 and the light source drive section 350.

[0179] In this Figure 8 , in order to clearly show the state of support and fixation of each structural member, a ground symbol of an electric circuit is used to indicate each portion of the device housing 340. Specifically, Figure 8 the ground symbol 340 shown in the figure indicates that each of the optical element drive section 330 and the light source drive section 350 is supported and fixed by the device housing 340.

[0180] In addition, like the lighting device 200 shown in Figure 5 , the diffractive optical element 320 is supported by the optical element drive section 330 in a state of being movable with respect to the device housing 340. Also, the light source 310 is supported by the light source drive section 350 in a state of being movable with respect to the device housing 340. Here, the magnification lens 312a and the collimator lens 312b (shaping optical system 312), which are separate structural members of the light source 310, are fixed to the light emitting section 311 and move together with the light emitting section 311. Figure 8The broken line extending downward from the magnifying lens 312a and the collimating lens 312b and the ground mark 311 shown at the left end of the broken line in the figure indicate that these structural elements are supported and fixed by the light emitting portion 311. As a result, the light source driving portion 350 functions to drive the light source 310 as a whole.

[0181] In this Figure 8 In the figure, for the sake of convenience of explanation, an XYZ three-dimensional perpendicular coordinate system is defined with respect to the geometrical positional relationship of each structural element constituting the illumination device 300 to each other. The illumination device 300 is installed in a vehicle in such a manner that the advancing direction becomes the positive direction of the X axis, and an illumination target surface U (a road surface in front) is defined on a plane parallel to the XY plane. In order to illuminate the illumination target surface U, the light source 310 has a function of radiating light for illumination in the positive direction of the X axis in the reference state shown in the figure. However, as will be described later, the orientation of the light source 310 can be changed by the light source driving portion 350.

[0182] Figure 8 The functions of the light source 310 and the diffractive optical element 320 in the reference state shown in the figure are completely the same as those of the light source 210 and the diffractive optical element 220 in the illumination device 200 of the second embodiment shown in the figure. Figure 5 The functions of the light source 310 and the diffractive optical element 320 in the reference state shown in the figure are completely the same as those of the light source 210 and the diffractive optical element 220 in the illumination device 200 of the second embodiment shown in the figure. The light source 310 has a light emitting portion 311 generating a laser beam and a shaping optical system 312 widening the laser beam to generate parallel incident light L, and the shaping optical system 312 has a magnifying lens 312a and a collimating lens 312b. The parallel incident light L shaped by the shaping optical system 312 is incident on an incident surface P2 of the diffractive optical element 320. In the case of the example shown in the figure, the incident region on the incident surface P2 where the parallel incident light L is incident is a circular region shown by a broken line.

[0183] The diffractive optical element 320 functions to diffract the parallel incident light L from the light source 310 and project a desired projection pattern E on the illumination target surface U by the obtained diffracted light Ld. In the case of this embodiment, the diffractive optical element 320 also has the same function as that of the diffractive optical element 120, 220 shown in the figure. Figure 1 、 Figure 5 The diffractive optical element 320 shown in the figure is also composed of a hologram recording medium in which interference fringes corresponding to the center wavelength of the laser light emitted from the light emitting portion 311 are recorded, and in which interference fringes for generating a reproduced image which becomes the projection pattern E on the illumination target surface U are recorded. As described above, the diffractive optical element 320 can be produced by using object light and reference light from a scattering plate of a real object, or can be produced by using a method of computer-synthesizing a hologram.

[0184] Thus, Figure 8 The structure and the functions of the light source 310 and the diffractive optical element 320 shown in the figure are completely the same as those of the light source 210 and the diffractive optical element 220 in the illumination device 200 of the second embodiment shown in the figure. Figure 1 、Figure 5 The light sources 110, 210 and the diffractive optical elements 120, 220 shown have the same functions, and detailed descriptions thereof are omitted here.

[0185] On the other hand, the optical element drive section 330 and the light source drive section 350 used in the illumination device 300 of this third embodiment perform actions for changing the position and orientation of the projected pattern E formed on the illumination target surface U. In the case of the illustrated embodiment, the projected pattern E is composed of an arrow pattern in the direction D, but by performing the drive actions described below, the position and orientation of this projected pattern E can be changed.

[0186] Figure 5 The optical element drive section 230 has a function of rotating the diffractive optical element 220 about a rotation axis Ry that passes through the center point within the diffractive optical element 220 and is parallel to the Y axis, but Figure 8 The optical element drive section 330 has a function of rotating the diffractive optical element 320 about a rotation axis Rz that passes through the center point within the diffractive optical element 320 and is parallel to the Z axis. In the case of this embodiment, the rotation axis Rz is an axis that passes through the center position in the thickness direction of the diffractive optical element 320.

[0187] Figure 8 The case where the diffractive optical element 320 is in the reference state is shown, and both the incident surface P2 and the emergent surface P3 of the diffractive optical element 320 maintain a posture that is parallel to the YZ plane. On the other hand, the parallel incident light L is a parallel light beam in the positive direction of the X axis, and thus in the illustrated reference state, the parallel incident light L is a parallel light beam that is perpendicular to the incident surface P2 and is incident from a direction that is perpendicular to the incident surface P2. Therefore, the optical element drive section 330 rotates the diffractive optical element 320 about the rotation axis Rz that is perpendicular to the parallel incident light L.

[0188] Here, as shown in the drawing, in the reference state, a normal line N30 is erected on the incident surface P2, and the optical axis C of the parallel incident light L is parallel to this normal line N30. On the other hand, the illustrated normal line N31 indicates a normal line erected on the incident surface P2 when the diffractive optical element 320 is rotated about the rotation axis Rz to become the first rotated state, and the illustrated normal line N32 indicates a normal line erected on the incident surface P2 when the diffractive optical element 320 is rotated in the reverse direction about the rotation axis Rz to become the second rotated state. In the case of the illustrated example, the normal line N31 is a normal line formed by inclining the normal line N30 toward the front of the drawing (negative direction of the Y axis), and the normal line N32 is a normal line formed by inclining the normal line N30 toward the back of the drawing (positive direction of the Y axis). Therefore, the diffractive optical element 320 is rotated in the lateral direction shown by the arrow M6 with the rotation axis Rz as the central axis.

[0189] As shown in the figure, the optical element driving section 330 has a driving mechanism 331 and a support arm 332 in order to change the orientation of the incident surface P2 of the diffractive optical element 320 to the lateral direction, and has a function of supporting the diffractive optical element 320 and rotating the diffractive optical element 320 around the rotation axis Rz as a center axis in the direction shown by the arrow M6. That is, the driving mechanism 331 has a function of rotating the support arm 332 around the rotation axis Rz as a center axis. Such a driving mechanism 331 can be configured using a publicly known mechanism, and thus detailed description thereof is omitted here.

[0190] Thus, Figure 5 the diffractive optical element 220 shown in the figure is rotated around the rotation axis Ry parallel to the Y axis, and in contrast to this, Figure 8 the diffractive optical element 320 shown in the figure is rotated around the rotation axis Rz parallel to the Z axis. The difference between the rotation axes is Figure 5 the large difference between the illumination device 200 of the second embodiment shown in the figure and Figure 8 the illumination device 300 of the third embodiment shown in the figure.

[0191] In the illumination device 300 of this third embodiment, the operation of driving the diffractive optical element 320 by the optical element driving section 330 is performed, and at the same time, the operation of driving the light source 310 by the light source driving section 350 is also performed. That is, the light source driving section 350 performs a driving operation of changing the orientation of the light source 310 to the lateral direction in order to change the orientation of the light L from the light source 310 in accordance with the change in the orientation of the incident surface P2 of the diffractive optical element 320.

[0192] As shown in the figure, the light source driving section 350 has a driving mechanism 351 and a support arm 352 in order to change the orientation of the light source 310 to the lateral direction, and has a function of supporting the light source 310 and rotating the light source 310 to the direction shown by the arrow M7. Such a driving mechanism 351 can be configured using a publicly known mechanism, and thus detailed description thereof is omitted here.

[0193] In addition, it is desirable that the driving operation of the light source driving section 350 is preferably an operation of rotating the light source 310 around the rotation axis Rz parallel to the Z axis. Thereby, the light source 310 and the diffractive optical element 320 are integrated and rotated around the rotation axis Rz, and thus it is possible to change the relative positions of the device housing 340 with respect to these while maintaining the relative positional relationship of the light source 310 and the diffractive optical element 320 to be constant.

[0194] In other words, if the ideal driving method described above is adopted, the light source driving section 350 changes the direction of the light L from the light source 310 in such a manner that the optical axis C of the incident light incident on the diffraction optical element 320 is kept constant with respect to the angle formed by the normal line N30 of the incident plane P2 of the diffraction optical element 320 (0° in the case of the illustrated example), and thus the geometric position of the incident light (parallel incident light L) with respect to the diffraction optical element 320 is always kept constant, and a part of the cross section of the parallel incident light L does not extend outside the incident plane P2 of the diffraction optical element 320.

[0195] However, in terms of practicality, even if the rotation axis of the light source 310 and the rotation axis Rz of the diffraction optical element 320 are not completely coincident, no major problem occurs. In fact, in the case of the illumination device 300 shown in the illustrated example, the rotation axis Rz of the diffraction optical element 320 becomes the central axis of the support arm 332, and, on the other hand, the rotation axis of the light source 310 becomes the central axis of the support arm 352, and the rotation axes of the two are different. However, any of the rotation axes is set to an axis parallel to the Z axis, and thus the direction of the light L from the light source 310 changes in accordance with the change in the direction of the incident plane P2 of the diffraction optical element 320 (when the direction parallel to the illumination target plane U is referred to as the horizontal direction, the deflection angle of the normal line N30 in the horizontal direction is made to correspond to the deflection angle of the light L in the horizontal direction.). Therefore, in terms of practicality, even if the structure of the illumination device 300 shown in the illustrated example is adopted, driving operation without failure can be performed. Figure 8 Figure 9

[0196] Thus, when the rotation axis of the light source 310 and the rotation axis Rz of the diffraction optical element 320 are not coincident, the relative positional relationship of the light source 310 and the diffraction optical element 320 is kept constant, and a part of the cross section of the parallel incident light L can extend outside the incident plane P2 of the diffraction optical element 320, but even if such extension occurs, the amount of light used for illumination is only slightly reduced, and thus no major problem occurs (it is preferable to cut off the extended light by a diaphragm). Of course, in order to prevent such extension, the size of the diffraction optical element 320 can also be designed to be slightly larger.

[0197] As a result, as in the illustrated example, if the diffraction optical element 320 is rotated by the support arm 332 and the light source 310 is rotated by the support arm 352, the ideal driving method described above cannot be adopted, but in terms of practicality, no major problem occurs. Furthermore, if the structure of the illustrated example is adopted, the device can be further miniaturized and simplified.

[0198] ​​Of course, in order to perform the ideal driving action described above, the light source drive unit 350 can be configured, for example, by a track on an arc centered on the rotation axis Rz and a drive mechanism that moves the light source 310 along the track. In this case, the device will be larger and more complex, but a portion of the cross-section of the parallel incident light L will not extend outward from the incident surface P2 of the diffractive optical element 320.

[0199] Thus, if the orientation of the incident surface P2 of the diffractive optical element 320 is changed by the optical element driving unit 320, and the orientation of the light L from the light source 310 is changed by the light source driving unit 350 according to this orientation change, the beam composed of the diffracted light Ld emitted from the exit surface P3 of the diffractive optical element 320 will change its direction of travel. As a result, the position and orientation of the projected pattern E formed on the illuminated object surface U also change. The driving mechanisms 331 and 351 can rotate the diffractive optical element 320 and the light source 310 in any direction by any amount, and by stopping this rotation at any position, the diffractive optical element 320 and the light source 310 can be made stationary in any rotational state. Therefore, the projected pattern E can be displayed in the desired position and orientation.

[0200] Figure 8 yes Figure 8 The diagram shows a top view of the lighting device 300 (some structural components are omitted). Solid lines in the diagram represent... Figure 8 The diagram shows the positions of various structural components and the laser beam path in the reference state (the state in which the incident surface P2 and the exit surface P3 of the diffractive optical element 320 are parallel to the YZ plane). Specifically, the light-emitting unit 311, shown in solid lines, emits laser light in the positive X-axis direction. This laser light is shaped into a parallel incident beam L parallel to the X-axis by the magnifying lens 312a and the collimating lens 312b. The optical axis C, shown in solid lines in the diagram, corresponds to the central axis of the beam constituting this parallel incident beam L. In the illustrated embodiment, this optical axis C becomes the axis passing through the center point of the plate-shaped diffractive optical element 320.

[0201] The diffractive optical element 320, shown by solid lines in the figure, represents the position of the diffractive optical element 320 in the reference state as viewed from above. Parallel incident light L, shown by solid lines, is incident from the left side of the figure onto the incident surface P2, and is diffracted as light Ld, shown by solid lines, from the exit surface P3, illuminating the object surface U (a plane parallel to the XY plane). The figure shows an example of the range where the diffracted light Ld (solid lines), based on the parallel incident light L (solid lines) incident on the diffractive optical element 320, reaches the projection points Q41-Q42 on the object surface U.

[0202] The diffractive optical element 320 is a holographic recording medium. Therefore, in principle, the diffracted light incident on any point on the diffractive optical element 320 will reach the range shown by projection points Q41 to Q42, forming a projection pattern E. The projection pattern E formed on the illumination object surface U is as follows: Figure 9 In the case of the arrow shape shown, when viewed from the car, projection point Q41 forms the right side of the arrow shape, and projection point Q42 forms the left side of the arrow shape.

[0203] On the other hand, the dashed line in the figure represents the first rotation state (the incident surface P2 and the exit surface P3 of the diffractive optical element 320 rotate from the reference state with the rotation axis Rz as the central axis). Figure 8 The positions of each structural component (in a counter-clockwise rotation state) and the optical path of the laser are shown. Here, an example is shown in which the light source 310 and the diffractive optical element 320 both rotate about the rotation axis Rz to perform the ideal driving action described above. Therefore, the angle formed by the optical axis C of the incident light and the normal to the incident surface P2 of the diffractive optical element 320 (0° in the illustrated example) remains constant, and diffraction occurs on the diffractive optical element 320 under optimal conditions.

[0204] However, the relative position of the diffractive optical element 320 to the illumination target surface U changes. Therefore, the parallel incident light L (shown as dashed lines) incident from the left side of the figure onto the incident surface P2 is transformed into diffracted light Ld (shown as dashed lines) from the exit surface P3 and irradiates the illumination target surface U. As a result, the diffracted light Ld (dashed lines) based on the parallel incident light L (dashed lines) incident on the diffractive optical element 320 reaches the range shown by projection points Q51 to Q52 on the illumination target surface U. The projection pattern E formed on the illumination target surface U is as follows: Figure 9 In the case of the arrow shape shown, when viewed from the car, projection point Q51 forms the right side of the arrow shape, and projection point Q52 forms the left side of the arrow shape.

[0205] Furthermore, the dashed line in the figure represents the second rotation state (the incident surface P2 and the exit surface P3 of the diffractive optical element 220 rotate from the reference state with the rotation axis Rz as the central axis). Figure 8 The positions of the various structural components (rotating clockwise in the middle) and the optical path of the laser are shown. Here, an example is shown in which the light source 310 and the diffractive optical element 320 both rotate about the rotation axis Rz to perform the ideal driving action described above. Therefore, the angle formed by the optical axis C of the incident light and the normal to the incident surface P2 of the diffractive optical element 320 (0° in the example shown) remains constant, and diffraction occurs on the diffractive optical element 320 under optimal conditions.

[0206] However, the relative position of the diffractive optical element 320 with respect to the illumination target surface U is changed, and thus the parallel incident light L shown by a single-dot chain line incident from the left side of the figure to the incident surface P2 is irradiated onto the illumination target surface U as the diffracted light Ld shown by a single-dot chain line from the emergent surface P3. As a result, the diffracted light Ld (single-dot chain line) based on the parallel incident light L (single-dot chain line) incident to the diffractive optical element 320 reaches the range shown by the projection points Q61 to Q62 on the illumination target surface U. In the case where the projection pattern E formed on the illumination target surface U is an arrow pattern as shown by the arrow pattern, the projection point Q61 constitutes the right side edge of the arrow pattern, and the projection point Q62 constitutes the left side edge of the arrow pattern when viewed from the automobile. Figure 10

[0207] Figure 8 is a plan view for explaining the change in the position and orientation of the projection pattern projected onto the illumination target surface U by the illumination device 300 shown by Figure 8 . The projection pattern E30 shown by a solid line in the figure indicates the pattern projected in the reference state, the projection pattern E31 shown by a broken line indicates the pattern projected in the first rotated state, and the projection pattern E32 shown by a single-dot chain line indicates the pattern projected in the second rotated state. Any of the projection patterns is a pattern of an arrow pattern of substantially the same shape, but the projection pattern E31 is a pattern of a rotation angle -φ1 compared with the projection pattern E30, and the projection pattern E32 is a pattern of a rotation angle +φ1 (as described above, the angle around the clockwise direction is set as a positive angle).

[0208] At this time, regarding the distribution of the light beams diffracted by the diffractive optical element 320, particularly the profile, even if the diffractive optical element 320 is rotated, the change is not substantially made, and the shape of the projection pattern E is substantially maintained. In the case where the projection pattern E of the arrow pattern is adopted as in the illustrated embodiment, the position and orientation of the arrow pattern projected onto the illumination target surface U are changed by the driving actions based on the optical element driving section 330 and the light source driving section 350. In this way, in the case of the illustrated embodiment, the position and orientation of the projection pattern E of the arrow pattern can be changed by the optical element driving section 330 and the light source driving section 350 according to the rotation direction and rotation amount of the light source 310 and the diffractive optical element 320, and the projection pattern E can be moved along the rotation direction M8 constituting a circular arc centered on the rotation axis Rz.

[0209] In summary, in the illumination device 300 of the third embodiment described herein, in the case where the direction parallel to the illumination target surface U (in the Figure 8 ​In the case of the X-axis direction, Y-axis direction, etc., which are defined as horizontal, the optical element drive unit 330 rotates the diffractive optical element 320 so that the normal N30 standing on its incident surface P2 is displaced in the horizontal direction. The light source drive unit 350 can change the orientation of the light L from the light source 310 according to the change in the orientation of the diffractive optical element 320.

[0210] The axis of rotation does not necessarily have to be parallel to the Z-axis, but for practical purposes, it is preferable to be as follows: Figure 10 The illumination device 300 shown is configured such that a rotation axis Rz parallel to the Z-axis is set. This allows for efficient diffraction via the diffractive optical element 320, such as... Figure 8 The example shown allows the projected pattern E to move along the rotation direction M8, and the device can be easily designed.

[0211] As a result, in adopting Figures 11-12 In the illustrated embodiment, when defining a three-dimensional vertical coordinate system XYZ with mutually perpendicular X, Y, and Z axes, and defining a state in which the incident surface P2 of the diffractive optical element 320 is arranged in an orientation parallel to the YZ plane as a reference state, the light source 310 generates parallel incident light L parallel to the X-axis in this reference state, and the parallel incident light L is incident on the incident surface P2. Furthermore, the diffractive optical element 320 is constructed from a holographic recording medium, and interference fringes are recorded in this holographic recording medium to generate a regenerated image as a projection pattern E on the illumination target surface U parallel to the XY plane. The optical element drive unit 330 rotates the diffractive optical element 320 about a rotation axis Rz parallel to the Z-axis, and the light source drive unit 350 changes the orientation of the light L from the light source 310 along a plane parallel to the XY plane according to the change in the orientation of the diffractive optical element 320.

[0212] By adopting such a structure, a desired projection pattern E can be projected onto the surface U of the lighting object, such as the road surface, ground, bottom surface, underwater surface, and wall surface. Moreover, while generally maintaining the shape of the projection pattern E, its projection position and projection orientation can be changed.

[0213] <<<§4. Fourth Implementation>>>

[0214] Next, refer to Figure 11 The fourth embodiment of the present invention will now be described. Figure 8 This is a perspective view showing the overall structure of the lighting device 400 according to the fourth embodiment of the present invention. This lighting device 400 is a variation of the lighting device 300 of the third embodiment described in §3, and its basic structure is similar to... Figure 11 The basic structure of the lighting device 300 shown is roughly the same.

[0215] As shown in the figure, the illumination device 400 is provided with a light source 410, a diffractive optical element 420 that diffracts light L from the light source 410 to project a projection pattern E onto an illumination target surface U, an optical element drive section 430 that supports and drives the diffractive optical element 420, a light source drive section 450 that supports and drives the light source 410, and a device housing 440 (omitted from the figure) that houses them, similarly to the illumination device 300 described above.

[0216] The device housing 440 is a housing that houses the light source 410, the diffractive optical element 420, the optical element drive section 430, and the light source drive section 450, and in the case of the embodiment shown here, the device housing 440 is mounted to the front end portion of an automobile. The device housing 440 also functions to support and fix the optical element drive section 430 and the light source drive section 450.

[0217] In the case of the Figure 11 In order to clearly show the state of support and fixation of each structural element, ground marks of an electric circuit are used to indicate each portion of the device housing 440. Specifically, Figure 11 The ground marks 440 shown at the lower ends of the lines extending downward from the optical element drive section 430 and the light source drive section 450 in the case of the

[0218] The diffractive optical element 420 is supported by the optical element drive section 430 in a state of being movable with respect to the device housing 440, and the light source 410 is supported by the light source drive section 450 in a state of being movable with respect to the device housing 440. Here, the magnifying lens 412a and the collimating lens 412b (shaping optical system 412), which are separate structural elements of the light source 410, are fixed to the light emitting section 411 and move together when the light emitting section 411 moves. Figure 11 The ground marks 411 shown at the left ends of the broken lines extending downward from the magnifying lens 412a and the collimating lens 412b in the case of the

[0219] In the case of the Figure 8 In order to facilitate explanation, an XYZ three-dimensional perpendicular coordinate system is defined with respect to the geometric positional relationship of each structural element that constitutes the illumination device 400 to each other. The illumination device 400 is mounted to an automobile in such a manner that the direction of travel becomes the positive direction of the X axis, and the illumination target surface U (the road surface in front) is defined on a plane parallel to the XY plane. In order to illuminate the illumination target surface U, the light source 410 has the function of radiating a light beam in the positive direction of the X axis in the reference state shown in the figure. However, as will be described later, the orientation of the light source 410 can be changed by the light source drive section 450.

[0220] Should Figure 11 The light source 410, diffractive optical element 420, and light source driving unit 450 shown in the diagram each have the same characteristics as... Figure 8 The light source 310, diffractive optical element 320, and light source drive unit 350 shown have exactly the same structure and function, therefore, their descriptions are omitted here. On the other hand, Figure 11 The optical element driving section 430 shown has a connection with Figure 8 The optical element drive unit 330 shown has a slightly different structure and function. This will be explained below.

[0221] Figure 1 The optical element drive unit 430 shown, in addition to Figure 11 In addition to the functions of the optical element driving unit 330 shown, it also has Figure 11 The optical element drive unit 130 shown has the following functions: It rotates the diffractive optical element 320 about a rotation axis Rz that passes through the center point of the diffractive optical element 320 and is parallel to the Z axis; and it rotates the diffractive optical element 120 about a rotation axis Rx that passes through the center point of the diffractive optical element 120 and is parallel to the X axis. Figure 8 The optical element drive unit 430 shown has both functions, and has the function of rotating the diffractive optical element 420 about a rotation axis Rz that passes through its center point and is parallel to the Z-axis, and about a rotation axis Rx that passes through its center point and is parallel to the X-axis.

[0222] In other words, the optical element drive unit 430 functions to change the orientation of the incident surface P2 of the diffractive optical element 420 and to rotate the diffractive optical element 420 about a rotation axis Rx perpendicular to the rotation plane P1 including its incident surface P2. Therefore, the diffractive optical element 420 rotates along the rotation direction M6 and within the rotation plane P1 along the rotation direction M1. During this rotation, the drive mechanism 431 can be configured to rotate the support arm 432 about its central axis (rotation axis Rz) and to swing the support arm 432 about the rotation axis Rx. Such a drive mechanism 431 can be constructed using known mechanisms, therefore detailed descriptions are omitted here.

[0223] As a result, Figure 10 In the lighting device 400 of the fourth embodiment shown, except for Figure 1 The rotation of the projection pattern E of the lighting device 300 in the third embodiment shown (along...) Figure 4 In addition to the rotational action of M8 in the direction of rotation shown, it can also perform... Figure 12The rotation of the projection pattern E of the lighting device 100 in the first embodiment shown (along...) Figure 11 (The rotation action in the direction M2 shown). If these two rotation actions are combined and their respective rotation directions and amounts are adjusted, the projected pattern E can be moved parallel to the illuminated object surface U.

[0224] Figure 12 It is through Figure 13 This is a top view illustrating the change in position of the projection pattern E onto the illuminated object surface U by the lighting device 400. In this example, relative to the projection pattern E40 (shown as a solid line, the pattern obtained in the reference state), the projection pattern 41 (shown as a dashed line) moves parallel upwards in the view, and the projection pattern 42 (shown as a single-dot-dashed line) moves parallel downwards in the view. Thus, regarding the rotational movements about the rotation axis Rx and about the rotation axis Rz performed by the optical element drive unit 430, if the respective rotation directions and rotation amounts are appropriately adjusted, then... Figure 13 As shown, the projected pattern E can be moved parallel to the direction indicated by the movement direction M9. Of course, it is not limited to parallel movement; it can also perform movements with various degrees of freedom regarding position and orientation.

[0225] <<<§5. Fifth Implementation>>>

[0226] Next, refer to Figure 13 The fifth embodiment of the present invention will now be described. Figure 1 This is a block diagram showing the structure of the lighting device 500 according to the fifth embodiment of the present invention. The lighting device 500 is also a device for projecting a desired projection pattern E onto the object to be illuminated U. As shown in the figure, it includes a light source 510, a diffractive optical element 520 that diffracts the light L from the light source 510 to project the projection pattern E onto the object to be illuminated U, a device housing 540 that houses the light source 510 and the diffractive optical element 520, and a device housing drive unit 550 that drives the device housing 540.

[0227] exist Figure 1 In this diagram, the structural components described above are represented by block diagrams, but the specific structure of each component can be referenced from the structures of the previously described embodiments. Specifically, the light source 510 can adopt the same... Figure 1 The light source 110 shown has the same structure, and the diffractive optical element 520 can be adopted as... Figure 5 The diffractive optical element 120 shown has the same structure. The housing 540 can use any structure as long as it has the function of supporting and fixing the light source 510 and the diffractive optical element 520 and housing them inside.

[0228] In the illumination device 500, a light source driving section for driving the light source 510, an optical element driving section for driving the diffractive optical element 520 are not provided. Instead, a device housing driving section 550 for driving the device housing 540 is provided. The device housing driving section 550 functions to mount the device housing 540 to a prescribed mounting site 560, and to drive the device housing 540 in such a manner that the position or orientation of the device housing 540 with respect to the mounting site 560, or both, is changed. If the illumination device 500 is used for a vehicle, for example, the front grille of the vehicle is used as the mounting site 560, and the device housing 540 is mounted to the front grille via the device housing driving section 550.

[0229] The device housing driving section 550 has a driving mechanism that changes the relative positional relationship of the device housing 540 with respect to the mounting site 560. As this driving mechanism, a mechanism that rotates the device housing 540 about a prescribed rotation axis can be used, as with the driving mechanisms used by the light source driving section and the optical element driving section described in the foregoing embodiments. Of course, a mechanism that moves the device housing 540 parallel with respect to the mounting site 560, or the like, can also be used.

[0230] In this way, the position and orientation of the projected pattern E formed on the illumination target surface U can be changed by changing the relative positional relationship of the device housing 540 with respect to the mounting site 560, thereby changing the relative positional relationship of the diffracted light Ld with respect to the mounting site 560.

[0231] In the illumination device 500 of this fifth embodiment, the device housing 540 and each of the structural components housed therein are all driven, so the power burden of the device housing driving section 550 is greater than the power burden of the light source driving section and the optical element driving section in the foregoing embodiments, and the movement space of the device housing 540 needs to be sufficiently ensured. However, the light source 510 and the diffractive optical element 520 are provided within the device housing 540, so the advantage that a general illumination device proposed in the past can be used directly as the device housing 540 and the components housed therein is obtained.

[0232] <<<§6. Various modifications >>

[0233] In the foregoing, the first to fifth embodiments of the present application were described in §1 to §5, and various modifications with respect to each of these embodiments will be described here.

[0234] (1) Modification with respect to the rotation axis

[0235] In Figure 8In the first embodiment shown, the diffractive optical element 120 is rotated about a rotation axis Rx parallel to the X axis, and in Figure 5 In the second embodiment shown, the diffractive optical element 220 is rotated about a rotation axis Ry parallel to the Y axis, and in Figure 8 In the third embodiment shown, the diffractive optical element 320 is rotated about a rotation axis Rz parallel to the Z axis. In these embodiments, the illumination target plane U is set as a plane parallel to the XY plane, and the parallel incident light L is set as light parallel to the X axis in the reference state, and thus, as with the respective rotation axes Rx, Ry, Rz described above, there are advantages in terms of efficient diffraction, or miniaturization of the device, when the rotation axis parallel to a particular coordinate axis is set.

[0236] However, in the present application, the rotation axis for rotating the diffractive optical element need not necessarily be set as an axis parallel to the respective coordinate axes described above, but can be set in any direction. Thus, in the case of the first embodiment shown, Figure 1 In the second embodiment shown as a basic modification, when the direction perpendicular to the illumination target plane U is defined as the vertical direction Z, the optical element driving section 230 can rotate the diffractive optical element 220 about a rotation axis that is not parallel to the vertical direction (in the case where the rotation axis parallel to the vertical direction, Rz, is set, the third embodiment is obtained). Similarly, in the third embodiment shown as a basic modification, when the direction parallel to the illumination target plane U is defined as the horizontal direction, the optical element driving section 330 can rotate the diffractive optical element 320 about a rotation axis that is not parallel to the horizontal direction (in the case where the rotation axes parallel to the horizontal direction, Rx, Ry, are set, the first or second embodiment is obtained). Figure 1

[0237] Thus, in implementing the present application, the rotation axis of the diffractive optical element need not necessarily be set as an axis parallel to a particular coordinate axis, but when the rotation plane (a plane perpendicular to the rotation axis) is set as a plane parallel to the optical axis of the incident light L, the angle formed by the advancing direction of the parallel incident light L and the incident plane of the diffractive optical element becomes 0°, and in essence the parallel incident light L does not enter the incident plane, and thus the diffractive optical element needs to be set so as to rotate in a manner in which the rotation axis is in a plane that is not parallel to the optical axis of the incident light L that enters the diffractive optical element, in other words, in a manner in which the incident plane of the diffractive optical element is not parallel to the optical axis of the incident light L.

[0238] For example, in the case of the first embodiment shown, Figure 1 ​In the case of the illustrated illumination device 100 being a basic variation, when the incident surface P2 of the diffractive optical element 120 (and the rotation plane P1 including the incident surface P2) is set to be parallel to the XY plane, and the rotation axis is set to be parallel to the Z-axis, the parallel incident light L traveling in the positive X-axis direction will not illuminate the incident surface P2, and the illumination device 100 will essentially not function. Therefore, in Figure 1 In the case of the illumination device 100 shown, it is necessary to set the rotation plane P1 of the diffractive optical element 120 to a plane that is not parallel to the optical axis (X-axis) of the parallel incident light L.

[0239] In addition, in the case of Figure 5 In the case of the illumination device 100 shown as a basic variation, in order to obtain good diffraction efficiency, it is preferable to ensure that the diffraction conditions of the diffraction optical element 120 continuously satisfy the Bragg condition as much as possible during the rotation of the diffraction optical element 120. Therefore, in the rotation plane P1, it is preferable to set the incident angle of the parallel incident light L relative to the incident plane P2 to an orientation that continuously satisfies the aforementioned Bragg condition.

[0240] Furthermore, in Figure 8 In the case of the illumination device 100 shown, the rotation axis Rx is an axis passing through the center of the diffractive optical element 120. However, the rotation axis Rx does not necessarily have to pass through the center. It can be set to pass through a position detached from the center inside the diffractive optical element 120 or to pass through the outside of the diffractive optical element 120. However, in order to miniaturize the device, it is preferable to set it to pass through the inside of the diffractive optical element 120.

[0241] Similarly, in Figure 5 The lighting device 200 shown Figure 8 In the case of the illumination device 300 shown, the rotation axes Ry and Rz are axes passing through the center position in the thickness direction of the diffractive optical elements 220 and 320. However, the rotation axes Ry and Rz do not necessarily have to pass through the center position in the thickness direction. They can be set to a position that is separated from the center position in the thickness direction within the diffractive optical elements 220 and 320, or they can be set to pass through the surface (incident surface P2, exit surface P3) of the diffractive optical elements 220 and 320, or they can be set to pass through the outside of the diffractive optical elements 220 and 320. However, in order to miniaturize the device, it is preferable to set them to pass through the inside or surface of the diffractive optical elements 220 and 320.

[0242] (2) Examples of distortion of incident light incident on diffractive optical elements

[0243] In the previously described embodiments, the laser beam generated by the laser emitter is broadened by a magnifying lens and then shaped into parallel light by a collimating lens. Therefore, the light L incident on the diffractive optical element is a parallel beam. However, in this invention, the light incident on the diffractive optical element does not necessarily have to be a parallel beam. For example, a collimating lens may not be provided, and the light diffused into a cone shape by the magnifying lens may be directly incident on the diffractive optical element. In this case, when such conical diffused light is irradiated onto the diffractive optical element, the interference fringes that form the desired projection pattern E on the illuminated object surface U as a regenerated image through the diffracted light Ld can be recorded.

[0244] Furthermore, in the various embodiments described above, an example of parallel incident light L being incident perpendicularly to the diffractive optical element in a reference state was presented. However, the incident light relative to the diffractive optical element does not necessarily have to be incident perpendicularly to the incident surface; it can be incident at any angle. However, in order to efficiently generate the projection pattern E using diffracted light Ld, as in the embodiments described above, it is preferable to set it to be incident perpendicularly in a reference state.

[0245] (3) Modifications of the optical element drive unit and the light source drive unit

[0246] exist Figure 11 The second embodiment shown Figure 5 The third embodiment shown Figure 8 In the fourth embodiment shown, optical element driving units 230, 330, and 430 for driving diffractive optical elements 220, 320, and 420, and light source driving units 250, 350, and 450 for driving light sources 210, 310, and 410 are provided independently. However, a combined driving unit that combines the two can also be provided, and the diffractive optical elements and light sources can be supported by the combined driving unit and driven simultaneously.

[0247] In this way, if a combined drive unit that has the functions of both an optical element drive unit and a light source drive unit is provided, the diffractive optical element and the light source are driven as a whole, thus preventing changes in their relative positions and enabling the device to be miniaturized.

[0248] Furthermore, in Figure 11 The second embodiment shown Figure 5 The third embodiment shown Figure 11 In the fourth embodiment shown, all light sources 210, 310, and 410 are driven by light source driving units 250, 350, and 450. However, the light source driving unit does not necessarily have to drive all structural components of the light source at the same time; it may drive only a portion of the structural components of the light source.

[0249] For example, inFigure 8 In the case of the second embodiment shown, the magnification lens 212a and the collimator lens 212b, which are structural components of the shaping optical system 212, can be fixed to the device housing 240 by driving only the light emitting section 211 by the light source driving section 250. In this case, the position of incidence of the laser beam emitted from the light emitting section 211 to the magnification lens 212a changes, and the position and direction of the light L emitted from the collimator lens 212b change, and the light L does not become a complete parallel light beam, so the shape of the projection pattern E formed on the illumination target surface U can be slightly deformed or become unclear. However, if the degree of change or the degree of unclarity of the shape of the projection pattern E is within the range permitted in terms of practicality, no major malfunction occurs.

[0250] In this way, in the case of using a structure in which only the light emitting section 211 is driven by the light source driving section 250, the structure of the driving system can be simplified, and the device can be made smaller.

[0251] (4) Modified example regarding pluralization of light source and diffractive optical element

[0252] In the foregoing embodiments, the light source has a single laser light emitting section, but a plurality of laser light emitting sections can be provided as needed. In this case, the plurality of laser light emitting sections can be provided independently, or a light emitting section module in which a plurality of laser light emitting sections are arranged on a common substrate can be used.

[0253] Furthermore, for example, the plurality of laser light emitting sections can be composed of a laser light emitting section that oscillates light in the red light emitting wavelength region, a laser light emitting section that oscillates light in the green light emitting wavelength region, and a laser light emitting section that oscillates light in the blue light emitting wavelength region. In this case, by overlapping the three laser lights emitted from the plurality of laser light emitting sections, the illumination target surface U can be illuminated with illumination light of the desired color. By adjusting the radiant fluxes [unit: W] of these plurality of laser light emitting sections, the color of the illumination light can be adjusted.

[0254] In this way, the light source can have a plurality of laser light emitting sections having different radiant fluxes. Of course, the light source can have two laser light emitting sections or four or more laser light emitting sections having different light emitting wavelength regions, not limited to the example described above in which three laser light emitting sections of red, green, and blue are used. Furthermore, in order to increase the light emitting intensity, a plurality of laser light emitting sections can be provided for each light emitting wavelength region.

[0255] In addition, in the case where a plurality of laser light emitting sections are provided in the light source, a plurality of shaping optical systems can be provided corresponding to the plurality of laser light emitting sections.

[0256] On the other hand, in the illumination device of each of the above-described embodiments, only a single diffractive optical element is provided, but a plurality of diffractive optical elements can also be provided as needed. In particular, as described above, in the case where a plurality of laser light emitting portions are provided in the light source, separate diffractive optical elements can be respectively provided corresponding to the plurality of laser light emitting portions. In this case, even in the case where the plurality of laser light emitting portions oscillate laser light of different wavelength regions, each of the diffractive optical elements can efficiently diffract laser light of a different wavelength region generated by the corresponding laser.

[0257] In addition, in the case where the illumination device includes a plurality of diffractive optical elements, the optical element driving section can rotate the plurality of diffractive optical elements around the same rotation axis, or can rotate the plurality of diffractive optical elements around different rotation axes, respectively.

[0258] (5) Modification example regarding combination of each embodiment

[0259] As described above, Figure 1 The fourth embodiment shown in FIG. 4 is an embodiment in which the third embodiment shown in FIG. 3 (use of the rotation axis Rz) and the first embodiment shown in FIG. 1 (use of the rotation axis Rx) are combined, and is provided with a mechanism that rotates the diffractive optical element 420 around the rotation axis Rz and also rotates the diffractive optical element 420 around the rotation axis Rx. Figure 13 ​ This fourth embodiment is an embodiment for exemplifying one of the combinations of the first to third embodiments, but the combination examples of each of the embodiments are not limited to this fourth embodiment, and can be various combinations as needed. For example, the first embodiment (use of the rotation axis Rx) and the second embodiment (use of the rotation axis Ry) can also be combined. In this case, it is possible to move the formation position of the projection pattern E in the vertical direction (Z-axis direction) (move the illumination target surface U in the vertical direction).

[0260] This fourth embodiment is an embodiment for exemplifying one of the combinations of the first to third embodiments, but the combination examples of each of the embodiments are not limited to this fourth embodiment, and can be various combinations as needed. For example, the first embodiment (use of the rotation axis Rx) and the second embodiment (use of the rotation axis Ry) can also be combined. In this case, it is possible to move the formation position of the projection pattern E in the vertical direction (Z-axis direction) (move the illumination target surface U in the vertical direction).

[0261] Of course, it is also possible to combine all of the first to third embodiments. Furthermore, it is also possible to further combine the fifth embodiment shown in FIG. 5 on the basis of each of these embodiments. ​

[0262] In this way, by combining a plurality of embodiments, the degree of freedom of the position and orientation of the projection pattern E on the illumination target surface U is significantly improved, and it is possible to make the amount of change in the position and orientation large.

[0263] (6) Modification example regarding utilization form

[0264] ​​In the above-described embodiment, an example in which the illumination device of the present application is used by being mounted to the front grille of an automobile is shown, but the utilization form of the illumination device of the present application is not limited to the example in which it is used by being mounted to the front grille of an automobile. For example, it is not limited to an automobile, but can be used by being mounted to a light unit of a general vehicle. Alternatively, it can also be used in a stationary state by being provided on a road surface.

[0265] (7) Other modifications

[0266] In addition, with respect to the present application, various modifications can be implemented within the scope of the following basic concepts.

[0267] The first basic concept of the present application is that an illumination device is constituted by a light source and a diffractive optical element that diffracts light from the light source, and the diffractive optical element is supported so as to rotate on a plane that is non-parallel to the optical axis of incident light that is incident on the diffractive optical element. In this case, it is preferable that a light emitting portion and a collimator lens be provided in the light source, and the collimator lens be disposed between the light emitting portion and the diffractive optical element along the optical path from the light emitting portion to the diffractive optical element.

[0268] Further, the second basic concept of the present application is that an illumination device is constituted by a light source and a diffractive optical element that diffracts light from the light source, the diffractive optical element is supported so as to act in such a manner that the orientation of its incident surface changes, and the light source is supported so as to act in such a manner that the angle formed by the optical axis of incident light that is incident on the diffractive optical element and the normal line of the incident surface of the diffractive optical element is kept constant. In this case, the diffractive optical element can be rotatably supported about an axis that is non-parallel to the vertical direction, or the diffractive optical element can be rotatably supported about an axis that is non-parallel to the horizontal direction, or the diffractive optical element can be further supported in such a manner that it rotates on a plane that is non-parallel to the optical axis of incident light that is incident on the diffractive optical element. Here, it is preferable that a light emitting portion and a collimator lens be provided in the light source, and the collimator lens be disposed between the light emitting portion and the diffractive optical element along the optical path from the light emitting portion to the diffractive optical element.

[0269] Industrial applicability

[0270] The illumination device of the present application is widely used for projecting a desired projection pattern on a predetermined illumination target surface such as a road surface, a ground surface, a floor surface, an underwater surface, a wall surface, and the like. Further, the projection position and the projection orientation of the projection pattern can be changed, and therefore, for example, the illumination device is most suitable for use in displaying a projection pattern such as an arrow that indicates the traveling direction of a vehicle at a desired position and in a desired orientation on a road.

[0271] Explanation of symbols

[0272] 100: Illumination device of the first embodiment

[0273] 110: light source

[0274] 111: light emitting portion

[0275] 112: shaping optical system

[0276] 112a: magnifying lens

[0277] 112b: collimating lens

[0278] 120: diffractive optical element (hologram)

[0279] 130: optical element driving portion

[0280] 131: driving mechanism

[0281] 132: support arm

[0282] 140: device housing

[0283] 200: illumination device of second embodiment

[0284] 210: light source

[0285] 211: light emitting portion

[0286] 212: shaping optical system

[0287] 212a: magnifying lens

[0288] 212b: collimating lens

[0289] 220: diffractive optical element (hologram)

[0290] 230: optical element driving portion

[0291] 231: driving mechanism

[0292] 232: support arm

[0293] 240: device housing

[0294] 250: light source driving portion

[0295] 251: driving mechanism

[0296] 252: support arm

[0297] 300: illumination device of third embodiment

[0298] 310: light source

[0299] 311: light emitting portion

[0300] 312: shaping optical system

[0301] 312a: magnifying lens

[0302] 312b: collimating lens

[0303] 320: diffractive optical element (hologram)

[0304] 330: optical element driving section

[0305] 331: driving mechanism

[0306] 332: support arm

[0307] 340: device housing

[0308] 350: light source driving section

[0309] 351: driving mechanism

[0310] 352: support arm

[0311] 400: illumination device of the fourth embodiment

[0312] 410: light source

[0313] 411: light emitting section

[0314] 412: shaping optical system

[0315] 412a: magnifying lens

[0316] 412b: collimating lens

[0317] 420: diffractive optical element (hologram)

[0318] 430: optical element driving section

[0319] 431: driving mechanism

[0320] 432: support arm

[0321] 440: device housing

[0322] 450: light source driving section

[0323] 451: driving mechanism

[0324] 452: support arm

[0325] 500: illumination device of the fifth embodiment

[0326] 510: light source

[0327] 520: diffractive optical element (hologram)

[0328] 540: device housing

[0329] 550: device housing driving section

[0330] 560: installation site

[0331] C: optical axis of incident light

[0332] D: direction indicating orientation of projected pattern

[0333] D10: reference direction of projected pattern

[0334] D11: first rotation direction of projected pattern

[0335] D12: second rotation direction of projected pattern

[0336] E: projected pattern

[0337] E10: reference pattern

[0338] E11: first rotated pattern

[0339] E12: second rotated pattern

[0340] E20: reference pattern

[0341] E21: first displaced pattern

[0342] E22: second displaced pattern

[0343] E30: reference pattern

[0344] E31: first rotated pattern

[0345] E32: second rotated pattern

[0346] E40: reference pattern

[0347] E41: first displaced pattern

[0348] E42: second displaced pattern

[0349] e1, e2: displacement amount of projected pattern

[0350] L: parallel incident light

[0351] Ld: diffracted light

[0352] L10, L20: diffracted light in reference state

[0353] L11, L21: diffracted light in first rotated state

[0354] L12, L22: diffracted light in second rotated state

[0355] M1: rotation direction of diffractive optical element

[0356] M2: direction of rotation of the projection pattern

[0357] M3: direction of rotation of the diffractive optical element

[0358] M4: direction of rotation of the light emitting section

[0359] M5: direction of displacement of the projection pattern

[0360] M6: direction of rotation of the diffractive optical element

[0361] M7: direction of rotation of the light emitting section

[0362] M8: direction of rotation of the projection pattern

[0363] M9: direction of movement of the projection pattern

[0364] N: normal line of the incidence plane P2 in the reference state

[0365] N20: normal line of the incidence plane P2 in the reference state

[0366] N21: normal line of the incidence plane P2 in the first rotated state

[0367] N22: normal line of the incidence plane P2 in the second rotated state

[0368] N30: normal line of the incidence plane P2 in the reference state

[0369] N31: normal line of the incidence plane P2 in the first rotated state

[0370] N32: normal line of the incidence plane P2 in the second rotated state

[0371] O: origin of the XYZ three-dimensional perpendicular coordinate system

[0372] P1: rotation plane

[0373] P2: incidence plane (light receiving plane)

[0374] P3: emission plane

[0375] Q1, Q2: prescribed points on the diffractive optical element

[0376] Q11 to Q62: projection points

[0377] Rx: rotation axis parallel to the X axis

[0378] Ry: rotation axis parallel to the Y axis

[0379] Rz: rotation axis parallel to the Z axis

[0380] U: illumination target plane

[0381] X: Coordinate axis of XYZ three-dimensional perpendicular coordinate system

[0382] Y: Coordinate axis of XYZ three-dimensional perpendicular coordinate system

[0383] Z: Coordinate axis of XYZ three-dimensional perpendicular coordinate system

[0384] + θ1: 1st rotation angle

[0385] - θ2: 2nd rotation angle

[0386] - φ1: 1st rotation angle

[0387] + φ2: 2nd rotation angle

Claims

1. An illuminating device (100) which projects a desired projection pattern (E) onto an illuminating object plane (U), The illuminating device (100) is characterized by comprising: a light source (110); a diffractive optical element (120) which diffracts light (L) from the light source (110) to project the projection pattern (E) onto the illuminating object plane (U); and an optical element driving section (130) which supports and drives the diffractive optical element (120), The optical element driving section (130) determines a rotation axis (Rx) which is perpendicular to a rotation plane (PI) including an incident plane (P2) of the diffractive optical element (120), and rotates the diffractive optical element (120) around the rotation axis (Rx), an optical axis (C) of the light (L) from the light source (110) coincides with the rotation axis (Rx).

2. The illuminating device (100) according to claim 1, characterized in that the light source (110) has a light emitting section (111) which generates a light beam, and a shaping optical system (112) which widens the light beam to generate parallel incident light (L), and the parallel incident light (L) is made incident on the incident plane (P2) of the diffractive optical element (120).

3. The illuminating device (100) according to claim 2, characterized in that the diffractive optical element (120) is arranged so that its incident plane (P2) is perpendicular with respect to the parallel incident light (L), the optical element driving section (130) rotates the diffractive optical element (120) on a rotation plane (PI) including the incident plane (P2).

4. The illuminating device (100) according to claim 1, characterized in that when an XYZ three-dimensional orthogonal coordinate system having an X axis, a Y axis, and a Z axis which are orthogonal to each other is defined, the light source (110) generates parallel incident light (L) which is parallel to the X axis, and makes the parallel incident light (L) incident on the incident plane (P2) of the diffractive optical element (120), the diffractive optical element (120) is composed of a hologram recording medium which is arranged in parallel with a YZ plane, and in which an interference fringe for generating a reproduced image which is the projection pattern (E) on an illuminating object plane (U) which is parallel to an XY plane is recorded, the optical element driving section (130) rotates the diffractive optical element (120) on a rotation plane (PI) which is parallel to the YZ plane.

5. The illuminating device (100) according to claim 1, characterized in that the illuminating device (100) further comprises a device housing (140) which houses the light source (110), the diffractive optical element (120), and the optical element driving section (130), and supports and fixes the light source (110) and the optical element driving section (130).

6. The illuminating device (100) according to any one of claims 1 to 5, characterized in that the rotation axis (Rx) is arranged at a position through the inside or surface of the diffractive optical element (120).

7. The illumination device (100) according to claim 2, characterized in that The shaping optical system (112) has a magnifying lens (112a) that refracts the light beam generated by the light emitting portion (111) to widen it, and a collimating lens (112b) that shapes the light from the magnifying lens (112a) into parallel incident light (L), and causes the parallel incident light (L) to be incident on the incidence plane (P2) of the diffractive optical element (120).

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