Lighting device, lighting method, and lighting system design method

Abstract

To cause an observer to recognize information on a projection pattern appropriately.SOLUTION: A lighting system 1 includes a projection surface 3 and a lighting device 10 for projecting a projection pattern 4 including information onto the projection surface 3. The projection pattern 4 is intended to be observed from a predetermined observation position 7 separated from the projection surface 3. The projection pattern 4 includes a plurality of element patterns 5 aligned in one direction from a predetermined position 9 separated in one direction from a crossing position 8 with a perpendicular drawn from the observation position 7 with respect to the projection surface 3, to a side opposite to the crossing position 8. An angle θA formed by a line connecting each of the two ends in one direction of the projection pattern 4 with the observation position 7 is 10° or less. Angles θ1, θ2, ..., θn formed by a line connecting each of the two ends in one direction of each element pattern 5 with the observation position 7 is 5° or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a lighting system, a lighting method, and a method for designing a lighting system. [Background technology]

[0002] Laser light sources that emit coherent light are sometimes used as the light source for lighting devices. Laser light sources generally have a smaller light-emitting spot size and higher brightness than LEDs (Light Emitting Devices). In addition, because they emit coherent light, they can improve directionality and transmit a sufficient amount of light over long distances. Furthermore, by using various optical elements such as diffractive optical elements and lens arrays, as well as microdisplays, it is possible to precisely control the light distribution.

[0003] An illumination device has been proposed that combines such a laser light source with an optical element to project a desired projection pattern, as described in Patent Document 1. In the illumination device disclosed in Patent Document 1, laser light generated by a single light source is diffracted by a single optical element such as a hologram. The desired projection pattern is formed from the light from the single light source by diffraction by the optical element. This projection pattern is projected onto a projection surface located at a distance from the illumination device.

[0004] When a laser light source and a diffractive optical element are used as the light source of an illumination device, a desired projection pattern can be projected without using an imaging optical system. Furthermore, when a laser light source is used as the light source of an illumination device, the divergence angle of the light projected from the illumination device can be reduced. As a result, the projection pattern projected on the projection surface can be displayed more efficiently and clearly than when an LED is used as the light source. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-132707 Summary of the Invention [Problem to be solved by the invention]

[0006] However, information about a projection pattern projected by an illumination device can be difficult for an observer to recognize. In particular, when the projection pattern extends in one direction, it is difficult to recognize the projection pattern in that direction at a glance. The present disclosure aims to enable an observer to properly recognize information about the projection pattern. [Means for solving the problem]

[0007] The lighting system of the present disclosure comprises: A projection surface; a lighting device that projects a projection pattern including information onto the projection surface, the projection pattern is intended to be observed from a predetermined observation position spaced apart from the projection surface; the projection pattern has a plurality of element patterns arranged in one direction from a predetermined position spaced in one direction from an intersection position with a perpendicular line dropped from the observation position to the projection surface, to an opposite side of the intersection position, an angle formed by a line connecting each of the two ends of the projection pattern in one direction with the observation position is 10° or less; The angle formed by the lines connecting the observation position to both ends of each element pattern in the one direction is 5° or less.

[0008] In the illumination system of the present disclosure, the angle formed by the lines connecting the observation position to both ends of the projection pattern in the one direction may be 3° or more.

[0009] In the lighting system of the present disclosure, the angle formed by the lines connecting the observation position to both ends of each element pattern in the one direction may be 0.1° or more.

[0010] In the illumination system of the present disclosure, the angle formed by the lines connecting the observation position with both ends of each element pattern in the other direction that is not parallel to the one direction may be 5° or less.

[0011] In the lighting system of the present disclosure, the angle formed by the lines connecting the observation position with both ends of each element pattern in the other direction that is not parallel to the one direction may be 0.1° or more.

[0012] In the lighting system of the present disclosure, the plurality of element patterns may each contain the same information.

[0013] In the illumination system of the present disclosure, the illumination device may include a light source that emits coherent light, and a diffractive optical element that diffracts the coherent light from the light source to form the projection pattern.

[0014] A first illumination method of the present disclosure is an illumination method for projecting a projection pattern onto a projection surface by an illumination device, the method comprising: determining a viewing position at which the projection pattern is viewed; determining a placement position of the lighting device relative to the projection surface; and determining the projection pattern to be projected from the illumination device based on the relationship between the observation position and the placement position.

[0015] A second illumination method of the present disclosure is an illumination method for projecting a projection pattern onto a projection surface by an illumination device, the method comprising: determining a viewing position at which the projection pattern is viewed; determining the projection pattern to be projected from the illumination device; and determining a placement position of the illumination device relative to the projection surface based on the relationship between the observation position and the projection pattern.

[0016] A lighting system design method according to the present disclosure is a lighting system design method for projecting a projection pattern onto a projection surface by a lighting device, the method comprising: determining a viewing position at which the projection pattern is viewed; determining an observation pattern observed from the observation position; determining the projection pattern based on the observation position and the observation pattern; determining a placement position of the lighting device relative to the projection surface; determining a light distribution pattern emitted from the lighting device based on the relationship between the observation position and the placement position so that the projection pattern is projected from the lighting device onto the projection surface; and designing a diffractive optical element included in the lighting device so as to form the light distribution pattern. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to allow an observer to appropriately recognize information about a projection pattern. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view that schematically shows the general configuration of a lighting system. [Figure 2] FIG. 2 is an enlarged plan view of the illumination system observed from the normal direction of the projection plane. [Figure 3] FIG. 3 is a diagram showing a state in which a projection pattern projected by an illumination system is observed by an observer. [Figure 4] FIG. 4 is a diagram showing how element patterns of a projection pattern projected by an illumination system are observed by an observer. [Figure 5] FIG. 5 is a diagram showing a state in which element patterns of a projection pattern projected by an illumination system are observed by an observer when observed from a direction different from that shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings accompanying this specification, the scale and aspect ratios of the actual objects have been appropriately changed and exaggerated for the sake of ease of illustration and understanding.

[0020] Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of length and angle, are not to be construed as being bound by strict meanings, but rather as including a range within which similar functions can be expected.

[0021] Fig. 1 is a perspective view showing a schematic configuration of a lighting system 1 according to the present embodiment. As shown in Fig. 1, the lighting system 1 includes a projection surface 3 and a lighting device 10. In the lighting system 1, a projection pattern 4 is projected onto the projection surface 3 by the lighting device 10.

[0022] The projection surface 3 functions as a display surface that displays the projection pattern 4 projected from the lighting device 10 so that it can be properly observed by surrounding observers. The projection surface 3 is a surface spaced apart from the lighting device 10. The projection surface 3 is preferably a flat surface so as to properly display the projection pattern 4. As shown in FIG. 1 , in this embodiment, the projection surface 3 has a predetermined width in a first direction d1 and extends in a second direction d2. Such a projection surface 3 is, for example, a part of the surface of a road or a passage. The length (width) of the projection surface 3 in the first direction d1 and the length in the second direction d2 are determined by the light distribution pattern of light diffracted by a diffractive optical element 14 (described later) of the lighting device 10 and the positional relationship between the projection surface 3 and the lighting device 10. In the illustrated example, the first direction d1 and the second direction d2 are perpendicular to each other.

[0023] The projection pattern 4 is a predetermined pattern that is displayed on the projection surface 3 and observed by the viewer. The projection pattern 4 includes, for example, predetermined information for the observer to observe. In the example shown in FIG. 1, the projection pattern 4 includes a plurality of arrows for route guidance or the like as the predetermined information. However, the information included in the projection pattern 4 is arbitrary, and may include not only symbols such as arrows, but also pictures, images, letters, numbers, and the like. Furthermore, the display color, size, character line type, and line width of the predetermined information are also arbitrary, and at least a portion of the predetermined information may be color-coded using multiple colors.

[0024] As shown in FIGS. 3 and 4 , the projection pattern 4 is intended to be observed by an observer from a predetermined observation position 7. That is, at the observation position 7, the projection pattern 4 is properly observed. For example, at the observation position 7, the observer can observe the entire projection pattern 4. The projection pattern 4 is observed by the observer as an observation pattern. For example, when the observer observes the entire projection pattern 4 as an observation pattern of approximately the same size, the projection pattern 4 becomes larger as it moves away from the observation position 7. The observation position 7 is spaced apart from the projection surface 3. The distance by which the observation position 7 is spaced apart from the projection surface 3 is, for example, the eye height of a person standing upright in front of the projection surface 3 or the eye height of an occupant of a moving object such as a car positioned above the projection surface 3. The distance by which the observation position 7 is spaced apart from the projection surface 3 is, for example, 70 cm or more and 250 cm or less.

[0025] The projection pattern 4 has a plurality of element patterns 5. The plurality of element patterns 5 are aligned in the second direction d2. In particular, the direction in which the plurality of element patterns 5 are aligned is the front-to-back direction relative to the viewer. That is, as shown in FIGS. 3 and 4 , the plurality of element patterns 5 are aligned in the second direction d2 from a predetermined position 9 that is spaced in the second direction d2 from an intersection position 8 with a perpendicular line dropped down from the observation position 7 on the projection surface 3, to the opposite side of the intersection position 8. The viewer can simultaneously observe the plurality of element patterns 5 aligned in the second direction d2.

[0026] The element pattern 5 contains part of the information of the projection pattern 4. The plurality of element patterns 5 may contain different pieces of information or may contain the same information. For example, as shown in Fig. 1, multiple element patterns 5 may each contain the same information, such as an arrow for route guidance. In this case, the arrows may have different directions, sizes, etc. for the same route guidance information. In this way, even when multiple element patterns 5 contain the same information, the element patterns 5 may have different sizes, shapes, etc.

[0027] The projection pattern 4 contains light with wavelengths in the visible light wavelength range so that it can be observed by an observer. Specifically, the projection pattern 4 includes light having a wavelength of 380 nm or more and 700 nm or less. In addition to the projection pattern 4, the illumination device 10 may also irradiate light outside the visible light wavelength range, such as light in the infrared range, light in the ultraviolet range, millimeter waves, or terahertz waves.

[0028] The lighting device 10 is a device that projects a projection pattern 4 onto a projection surface 3. In this embodiment, the lighting device 10 is used as part of a stationary information display light. However, the lighting device 10 can also be applied to various types of lighting, such as a searchlight. Such a lighting device 10 is installed, for example, on the ceiling or wall of a building. The lighting device 10 can also be installed on various mobile objects, such as vehicles such as automobiles and bicycles, as well as mobile objects such as ships, airplanes, and trains. Furthermore, the lighting device 10 can also be applied to terminals capable of displaying information, such as computer displays, mobile terminals such as tablets and smartphones, and televisions. Thus, the lighting device 10 includes not only those installed at a predetermined location as in this embodiment, but also mobile devices. In particular, the lighting device 10 may be carried by the observer who observes the projection pattern 4 projected by the lighting device 10. The lighting device 10 is placed at a predetermined placement position 11 where the projection pattern 4 can be appropriately projected onto the projection surface 3. In other words, the illumination device 10 arranged at the arrangement position 11 projects the projection pattern 4 onto the projection surface 3 in an appropriate direction and with an appropriate resolution.

[0029] 1, the illumination device 10 includes a light source 12, a shaping optical system 13, and a diffractive optical element 14. The illumination device 10 may further include a housing that houses the light source 12, the shaping optical system 13, and the diffractive optical element 14. Each of the components of the illumination device 10 will be described below.

[0030] The light source 12 emits coherent light, which is light with a uniform wavelength and phase. Various types of light sources can be used as the light source 12. Typically, a laser light source that emits laser light can be used as the light source 12 that emits coherent light. As a specific example, the light source 12 is configured as a semiconductor laser light source and is supported by, for example, a circuit board. In the example shown in FIG. 1 , three light sources 12 are provided, each emitting light of a different wavelength. The wavelengths of the light emitted by the light sources 12 correspond to the wavelengths of the light contained in the projection pattern 4. For example, when the projection pattern 4 is projected to include light in the visible light wavelength range, the light source 12 emits light in the visible light wavelength range. In this case, typically, the three light sources 12 emit coherent light in the red, green, and blue wavelength ranges, respectively. The light source 12 may also emit light outside the visible light wavelength range, such as light in the infrared range, light in the ultraviolet range, millimeter waves, or terahertz waves. The illustrated example is not limiting, and any number of light sources 12 may be used.

[0031] The shaping optical system 13 shapes the light emitted from the light source 12. In other words, the shaping optical system 13 shapes the shape of the light from the light source 12 in a cross section perpendicular to the optical axis and the three-dimensional shape of the light emission space. Typically, the shaping optical system 13 expands the cross-sectional area of ​​the projected light in a cross section perpendicular to the optical axis of the light. In particular, in the illustrated example, the shaping optical system 13 shapes the light emitted from the light source 12 into widened parallel light. That is, the shaping optical system 13 functions as a collimating optical system. As shown in FIG. 1 , the shaping optical system 13 includes a first lens 13a and a second lens 13b in this order along the optical path of the coherent light. The first lens 13a shapes the light emitted from the light source 12 into diverging light. The second lens 13b reshapes the diverging light generated by the first lens 13a into parallel light. That is, the second lens 13b functions as a collimating lens. 1, a plurality of shaping optical systems 13 are provided. The shaping optical systems 13 are provided corresponding to the respective light sources 12. Therefore, the number of shaping optical systems 13 is the same as the number of light sources 12.

[0032] The diffractive optical element 14 diffracts the light that has passed through the shaping optical system 13 to form the projection pattern 4. The light diffracted by the diffractive optical element 14 is projected onto the projection surface 3. In the example shown in FIG. 1, a plurality of diffractive optical elements 14 are provided. One diffractive optical element 14 is provided corresponding to each shaping optical system 13. Therefore, the number of diffractive optical elements 14 is the same as the number of shaping optical systems 13.

[0033] FIG. 2 shows an enlarged view of one diffractive optical element 14. As shown in FIG. 2, the diffractive optical element 14 includes a plurality of element diffractive optical elements 15. In particular, the plurality of element diffractive optical elements 15 are tiny, thin plate-like members that are two-dimensionally arranged on the same plane in the diffractive optical element 14 without any gaps between them. The element diffractive optical elements 15 diffract light and emit it from an emission surface 15a. Each of the plurality of element diffractive optical elements 15 diffracts light from the shaping optical system 13 to form a light distribution pattern. This light distribution pattern is projected onto the projection surface 3 to form the projection pattern 4. Each element diffractive optical element 15 may form the entire predetermined information displayed by the projection pattern 4, or may form a portion of the predetermined information.

[0034] The diffraction characteristics of each element diffractive optical element 15 are designed so that it correctly illuminates each illumination range of the corresponding projection surface 3, so that the specified information displayed by the projection pattern 4 projected onto the projection surface 3 can be properly displayed.

[0035] As shown in Figure 2, the diffraction characteristics of each element diffractive optical element 15 are adjusted so that the illumination width w along the first direction d1 of light diffracted by one element diffractive optical element 15 incident at any position along the second direction d2 on the projection surface 3 is the same as the illumination width w along the first direction d1 of light diffracted by another element diffractive optical element 15 incident at any position along the second direction d2 on the projection surface 3.

[0036] The element diffractive optical element 15 is typically a hologram element. By using a hologram element as the element diffractive optical element 15, it becomes easier to design the diffraction characteristics, and it is also relatively easy to design a hologram element that can display information of a predetermined position, size, and shape on the projection surface 3.

[0037] When elementary diffractive optical element 15 is configured with a hologram element, the above-mentioned diffraction characteristics can be designed relatively easily using a computer by using a computer generated hologram (CGH).

[0038] The element diffractive optical element 15 may be a phase-type diffractive optical element or an amplitude-type diffractive optical element. Furthermore, although the element diffractive optical element 15 is configured as a transmissive type in the example shown in FIG. 1 , it may also be configured as a reflective type. When the element diffractive optical element 15 is configured as a phase-type diffractive optical element, the microstructure constituting the element diffractive optical element 15 may employ a concave-convex pattern structure in which the optical path length changes depending on the incident position of light, or a pattern structure in which the refractive index changes depending on the incident position of light. A microstructure consisting of a concave-convex pattern is preferable because it can be mass-produced by resin molding using photolithography technology. Furthermore, when the element diffractive optical element 15 is configured as an amplitude-type diffractive optical element, the microstructure constituting the element diffractive optical element 15 may employ a structure in which the transmittance changes depending on the incident position of light.

[0039] Next, the relationship between the projection pattern 4 and the observation position 7 will be described with reference to FIGS.

[0040] 3 and 4 show a state in which an observer is observing a projection pattern 4 and a plurality of element patterns 5 from an observation position 7 in a direction parallel to the projection surface 3. In the illustrated example, the element patterns 5 are arrows for route guidance or the like. In particular, in the illustrated example, a plurality of element patterns 5, which are arrows of the same shape and size, are lined up in one direction (second direction d2).

[0041] The observer can observe the entire projection pattern 4 at a glance from the observation position 7. In other words, the observer can observe the entire projection pattern 4, i.e., all element patterns 5, from the observation position 7 without moving the viewpoint significantly. Because the projection pattern 4 is sufficiently small, the angle at which the observer views the entire projection pattern 4 at the observation position 7, i.e., the angle θ formed by the lines connecting the observation position 7 and both ends of the projection pattern 4 in the second direction d2, is A is sufficiently small. Specifically, the angle θ A is 10° or less, and preferably 8° or less. The projection pattern 4 has a size that allows it to be easily observed by an observer. Since the projection pattern 4 is large enough, the angle θ A is large enough. Specifically, the angle θ A is 3° or more, and preferably 5° or more.

[0042] At the observation position 7, the observer orients each element pattern 5 at angles θ1, θ2, . . . , θ n In other words, the observer observes the element patterns 5 by observing the angles θ1, θ2, ..., θ formed by the lines connecting the observation position 7 with both ends of the element patterns 5 in the second direction d2. n where n is the number of element patterns 5 arranged in the second direction d2, and in the example shown in FIG. 4, n is 4. Each element pattern 5 is sufficiently small in the second direction d2 so that an observer can recognize it by gazing at each element pattern 5 without moving the viewpoint in the second direction d2. Specifically, the element patterns 5 are arranged at angles θ1, θ2, ..., θ n is 5° or less, and preferably 4° or less. In addition, each element pattern 5 is sufficiently large in the second direction d2 so that the viewer can properly recognize each element pattern 5 in the second direction d2. Specifically, the angles θ1, θ2, ..., θ n is 0.1° or more, and preferably 1° or more.

[0043] 5 shows a state in which an observer is observing a plurality of element patterns 5 from an observation position 7 in a direction different from that shown in FIGS. 3 and 4, particularly from the normal direction of the projection plane 3. As shown in FIG. 5, at the observation position 7, the observer orients each element pattern 5 at angles φ1, φ2, ..., φ with respect to the first direction d1. n In other words, the observer observes the element patterns 5 by observing the angles φ1, φ2, ..., φ formed by lines connecting the observation position 7 with both ends of the element patterns 5 in the first direction d1. n Each element pattern 5 is sufficiently small in the first direction d1 so that an observer can recognize each element pattern 5 by gazing at it without moving the viewpoint in the first direction d1. Specifically, the angles φ1, φ2, ..., φ n is 5° or less, and preferably 4° or less. In addition, each element pattern 5 is sufficiently large in the first direction d1 so that the viewer can properly recognize each element pattern 5 in the first direction d1. Specifically, the angles φ1, φ2, ..., φ n is 0.1° or more, and preferably 1° or more.

[0044] Next, an illumination method for projecting the projection pattern 4 onto the projection surface 3 by the illumination device 10 will be described.

[0045] First, an observation position 7 is determined, which is the position of a person's eyes where the projection pattern 4 is expected to be observed on the projection surface 3. For example, the observation position 7 is determined by determining a position in a hallway where route guidance should be provided and then determining the height of the person's eyes at that position. Next, an arrangement position 11 of the lighting device 10 relative to the projection surface 3 is determined. The arrangement position 11 may be determined independently of the observation position 7, but should be a position where the light projected from the lighting device 10 onto the projection surface 3 is not obstructed by an observer positioned at the observation position 7. The projection pattern 4 to be projected from the lighting device 10 is then determined based on the relationship between the observation position 7 and the arrangement position 11. Specifically, the projection pattern 4 is determined so that the entire projection pattern 4 can be observed from the observation position 7, each element pattern 5 of the projection pattern 4 can be recognized, and the lighting device 10 can project the projection pattern 4 from the arrangement position 11 onto the projection surface 3 with an appropriate size, angle, and shape. The projection pattern 4 thus projected is observed by the observer at the observation position 7 as a predetermined observation pattern.

[0046] Alternatively, the projection pattern 4 may be projected onto the projection surface 3 by the illumination device 10 as follows. First, as in the illumination method described above, an observation position 7 is determined, which is the position of a person's eyes at which the projection pattern 4 is expected to be observed on the projection surface 3. Next, the projection pattern 4 to be projected from the illumination device 10 is determined. The projection pattern 4 is determined based on the size, angle, shape, etc. of the projection pattern 4 to be observed from the observation position 7. Then, based on the relationship between the observation position 7 and the projection pattern 4, an arrangement position 11 of the illumination device 10 with respect to the projection surface 3 is determined. Specifically, the arrangement position 11 is determined so that the illumination device 10 can project onto the projection surface 3 a projection pattern 4 that can be observed in its entirety at the observation position 7. The projection pattern 4 projected in this manner is observed by the observer at the observation position 7 as a predetermined observation pattern.

[0047] Next, a method for designing the lighting system 1 that projects the projection pattern 4 onto the projection surface 3 using the lighting device 10 will be described.

[0048] First, as in the above-described illumination method, an observation position 7 is determined, which is the position of a person's eyes where the projection pattern 4 is expected to be observed on the projection surface 3. Next, an observation pattern to be observed by the observer at the observation position 7 is determined. Then, based on the observation position 7 and the observation pattern, a projection pattern 4 to be projected onto the projection surface 3 by the illumination device 10 is determined. The projection pattern 4 is determined based on the size, angle, shape, etc. of the pattern to be observed from the observation position 7. Then, a placement position 11 of the illumination device 10 relative to the projection surface 3 is determined. The placement position 11 may be determined independently of the observation position 7, but should be a position where the light projected from the illumination device 10 onto the projection surface 3 is not obstructed by the observer positioned at the observation position 7. Then, based on the relationship between the observation position 7 and the placement position 11, a light distribution pattern to be emitted from the illumination device 10 is determined so that the projection pattern 4 is projected from the illumination device 10 onto the projection surface 3. Then, a diffractive optical element 14 of the illumination device 10 is designed to form this light distribution pattern. That is, the diffractive optical element 14 that forms the projection pattern 4 is designed so that the projection pattern 4 can be projected onto the projection surface 3 from the illumination device 10 arranged at the arrangement position 11 in such a way that the entire projection pattern 4 can be properly observed from the observation position 7. More specifically, the diffractive optical element 14 is designed so that the light from the illumination device 10 arranged at the arrangement position 11 becomes a light distribution pattern that forms the projection pattern 4 on the projection surface 3 by diffracting the light from the light source 12.

[0049] However, when a projection pattern projected by an illumination device extends in one direction, it can be difficult for an observer to recognize information about the projection pattern in that direction. The human visual field has a limit, and even within the visual field, visual acuity tends to decline the further away from the gaze point. The visual field can be divided into central vision, which allows for observation of even small details, and peripheral vision, which is visible but cannot be recognized as meaningful information. If a portion of the projection pattern falls outside the observer's central visual field from the point of gaze, the observer cannot observe the entire projection pattern at a glance or properly recognize each element pattern of the projection pattern, making it difficult to recognize the information about the projection pattern. On the other hand, if the projection pattern is within the observer's central visual field, the observer can observe the entire projection pattern at a glance.

[0050] In this embodiment, the angle θ formed by the lines connecting the observation position 7 and each of the two ends of the projection pattern 4 in one direction is A is 10° or less. This angle range corresponds to the range of the central visual field. Therefore, the observer can observe the entire projected pattern 4 at a glance at the observation position 7. In addition, the angles θ1, θ2, ..., θ formed by the lines connecting the observation position 7 and each of the two ends of the element pattern 5 in one direction are n is 5° or less. Therefore, the observer can properly recognize each element pattern 5 in one direction by gazing at each element pattern 5. In this way, in this embodiment, the entire projection pattern 4 and each element pattern 5 can be properly recognized. This allows the observer to properly recognize the information of the projection pattern 4.

[0051] The angle θ formed by the lines connecting the observation position 7 and each of the two ends of the projection pattern 4 in one direction A is 3° or more. Such a projection pattern 4 has a sufficient size in one direction when observed from the observation position 7. Therefore, the observer can easily observe the projection pattern 4 from the observation position 7.

[0052] The angles θ1, θ2, ..., θ formed by the lines connecting the observation position 7 to both ends of each element pattern 5 in one direction are n is 0.1° or more. Such element pattern 5 has a sufficient size in one direction when observed from observation position 7. Therefore, the observer can easily recognize the information contained in element pattern 5 from observation position 7.

[0053] Angles φ1, φ2, ..., φ formed by lines connecting the observation position 7 with both ends of the other direction non-parallel to one direction of each element pattern 5, i.e., the first direction d1 non-parallel to the second direction d2 n is 5° or less. Therefore, the viewer can properly recognize each element pattern 5 in another direction by gazing at each element pattern 5. This allows the viewer to properly recognize the information of the projection pattern 4.

[0054] Angles φ1, φ2, ..., φ formed by lines connecting the observation position 7 with both ends of the other direction non-parallel to one direction of each element pattern 5, i.e., the first direction d1 non-parallel to the second direction d2 n is 0.1° or more. Such a projection pattern 4 has a sufficient size in other directions when observed from the observation position 7. Therefore, the observer can easily observe the projection pattern 4 from the observation position 7.

[0055] As described above, the lighting system 1 of this embodiment includes the projection surface 3 and the lighting device 10 that projects the projection pattern 4 containing information onto the projection surface 3. The projection pattern 4 is intended to be observed from a predetermined observation position 7 that is spaced apart from the projection surface 3. The projection pattern 4 has a plurality of element patterns 5 that are arranged in one direction from a predetermined position 9 that is spaced apart in one direction from an intersection position 8 with a perpendicular line dropped down from the observation position 7 to the projection surface 3, to the opposite side of the intersection position 8. The angle θ formed by the lines connecting each of the two ends of the projection pattern 4 in one direction to the observation position 7 is A are 10° or less, and the angles θ1, θ2, ..., θ formed by the lines connecting the observation position 7 to both ends of each element pattern 5 in one direction are nis 5° or less. Such an illumination system 1 allows the observer to properly observe the entire projection pattern 4 and each element pattern 5, thereby allowing the observer to properly recognize the information of the projection pattern 4.

[0056] The aspects of the present disclosure are not limited to the above-described embodiments, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of the present disclosure, which is derived from the contents defined in the claims and their equivalents. [Explanation of symbols]

[0057] 1. Lighting system 3 Projection plane 4 Projection Patterns Five-element pattern 7 Observation position 8 Intersection 10. Lighting equipment 11 Location 12 light source 13 Shaping optical system 14 Diffractive optical elements 15-element diffractive optical element

Claims

1. A lighting device that projects a projection pattern containing information onto a projection surface, the projection pattern is intended to be observed from a predetermined observation position spaced apart from the projection surface; the projection pattern has a plurality of element patterns arranged in one direction from a predetermined position spaced in one direction from an intersection position with a perpendicular line dropped from the observation position to the projection surface, to an opposite side of the intersection position, an angle formed by a line connecting each of the two ends of the projection pattern in one direction with the observation position is 10° or less; an angle formed by a line connecting each of the two ends of each element pattern in one direction with the observation position is 5° or less.

2. The illumination device according to claim 1 , wherein an angle formed by a line connecting each of the two ends of the projection pattern in the one direction with the observation position is 3° or more.

3. 3. The illumination device according to claim 1, wherein an angle formed by a line connecting each of both ends of each element pattern in the one direction with the observation position is 0.1° or more.

4. The illumination device according to claim 1 , wherein an angle formed by a line connecting each of both ends of each element pattern in the other direction non-parallel to the one direction and the observation position is 5° or less.

5. The illumination device according to claim 1 , wherein an angle formed by a line connecting each of both ends of each element pattern in the other direction non-parallel to the one direction and the observation position is 0.1° or more.

6. The lighting device according to claim 1 , wherein each of the plurality of element patterns includes the same information.

7. 7. The illumination device according to claim 1, further comprising: a light source that emits coherent light; and a diffractive optical element that diffracts the coherent light from the light source to form the projection pattern.

8. 1. A lighting method for projecting a projection pattern onto a projection surface using a lighting device, comprising: determining a viewing position at which the projection pattern is viewed; determining a placement position of the lighting device relative to the projection surface; determining the projection pattern to be projected from the illumination device based on the relationship between the observation position and the placement position; the projection pattern determined in the step of determining the projection pattern has a plurality of element patterns arranged in one direction from a predetermined position spaced in one direction from an intersection position with a perpendicular line dropped from the observation position to the projection plane, to an opposite side from the intersection position, an angle formed by a line connecting each of the two ends of the projection pattern in one direction to the observation position is 10° or less, and an angle formed by a line connecting each of the two ends of each element pattern in one direction to the observation position is 5° or less.

9. 1. A lighting method for projecting a projection pattern onto a projection surface using a lighting device, comprising: determining a viewing position at which the projection pattern is viewed; determining the projection pattern to be projected from the illumination device; determining a position of the illumination device relative to the projection surface based on a relationship between the observation position and the projection pattern; the illumination device arranged at the arrangement position determined in the step of determining the arrangement position projects, onto the projection surface, from a predetermined position spaced in one direction from an intersection position with a perpendicular line dropped down from the observation position with respect to the projection surface, the projection pattern having a plurality of element patterns arranged in the one direction to the opposite side of the intersection position; an angle formed by a line connecting each of the two ends of the projection pattern in one direction to the observation position is 10° or less, and an angle formed by a line connecting each of the two ends of each element pattern in one direction to the observation position is 5° or less.

10. A method for designing an illumination system that projects a projection pattern onto a projection surface using an illumination device, comprising: determining a viewing position at which the projection pattern is viewed; determining an observation pattern observed from the observation position; determining the projection pattern based on the observation position and the observation pattern; determining a placement position of the lighting device relative to the projection surface; determining a light distribution pattern emitted from the lighting device based on the relationship between the observation position and the placement position so that the projection pattern is projected from the lighting device onto the projection surface; and designing a diffractive optical element included in the illumination device so as to form the light distribution pattern; the projection pattern has a plurality of element patterns arranged in one direction from a predetermined position spaced in one direction from an intersection position with a perpendicular line dropped from the observation position to the projection surface, to an opposite side of the intersection position, A method for designing an illumination system, wherein an angle formed by a line connecting each of the two ends of the projection pattern in one direction to the observation position is 10° or less, and an angle formed by a line connecting each of the two ends of each element pattern in one direction to the observation position is 5° or less.

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