Lighting device

Abstract

The present invention addresses the problem of accurately controlling the light energy density distribution of a projected image to a desired distribution when the projected image dynamically changes. A lighting device (100) is provided with a light source (3), a first optical system (1), a modulation element (5), and a second optical system (2). The first optical system (1) guides light output from the light source (3) to the modulation element (5). The modulation element (5) outputs modulated light from an output region, the modulated light being obtained by dynamically changing the intensity distribution of light that has entered via an entry region (500). The second optical system (2) forms a projected image (800) obtained by enlarging the modulated light and projecting the modulated light onto an irradiated surface (80). The entry region (500) has a trapezoidal shape of which the length of a short side (501) is S1 and the length of a long side (502) is S2. The optical energy density D1 at the short side (501) is greater than the optical energy density D2 at the long side (502).

Description

lighting equipment

[0001] The present disclosure relates generally to lighting devices, and more particularly to lighting devices that form a projected image on an illuminated surface.

[0002] The image projection device described in Patent Document 1 modulates light output from a light source and displays a projected image (projected image) on a projection surface (irradiated surface) via a projection optical system. The image projection device has a tilting unit that tilts an image surface where the projected image is focused, and an image generating unit that generates a deformed image by deforming an input image in response to an operation input by a user.

[0003] In a device such as that described in Patent Document 1, if the illuminated surface is tilted with respect to the optical axis, the light energy density distribution of the projected image may change compared to when the illuminated surface is perpendicular to the optical axis.

[0004] Japanese Patent Application Laid-Open No. 2022-114988

[0005] An object of the present disclosure is to provide an illumination device that can accurately control the light energy density distribution of a projected image to a desired distribution when the projected image changes dynamically.

[0006] An illumination device according to one aspect of the present disclosure includes a light source, a first optical system, a modulation element, and a second optical system. The first optical system guides light emitted from the light source to the modulation element. The modulation element has an entrance region and an exit region, and emits modulated light from the exit region, which is obtained by dynamically changing the intensity distribution of the light incident from the entrance region. The second optical system magnifies the modulated light emitted from the exit region of the modulation element and forms a projected image on an illuminated surface. The shape of the entrance region is a trapezoid with a short side length S1 and a long side length S2 that is parallel to the short side and longer than the short side. D1, which is the light energy density at the short side of the entrance region, is greater than D2, which is the light energy density at the long side of the entrance region.

[0007] Fig. 1 is a perspective view of an illumination device according to a first embodiment. Fig. 2 is a side cross-sectional view of the illumination device according to the same. Fig. 3 is a schematic diagram showing a process in which the illumination device according to the same forms a projected image. Fig. 4 is a plan view of a light source of the illumination device according to the same. Fig. 5 is a plan view of a light source of an illumination device according to a second embodiment. Fig. 6 is a side view of an illumination device according to a third embodiment. Fig. 7 is a side view of an illumination device according to a fourth embodiment. Fig. 8 is a side view of a light generation unit of an illumination device according to a modified example.

[0008] In the following embodiments, the lighting device of the present disclosure will be described using drawings. However, the following embodiments are merely a portion of various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, the following embodiments, including modified examples, may be realized by combining them as appropriate. Furthermore, the drawings described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0009] 1, the X-axis direction is defined as the left-right direction, the Y-axis direction as the front-rear direction (depth direction), and the Z-axis direction as the up-down direction. Furthermore, the positive direction in the X-axis direction is defined as the right side, the positive direction in the Y-axis direction as the rear side, and the positive direction in the Z-axis direction as the top side. However, these directions are merely examples and are not intended to limit the directions in which the lighting device 100 is used. Furthermore, the arrows indicating the various directions in the drawings are merely shown for explanatory purposes and do not have any substance.

[0010] The term "light energy density" used in this disclosure refers to the amount of light energy per unit area. The unit of light energy density is W / m2.

[0011] (Embodiment 1) (1) Overview (1.1) Basic Configuration Fig. 1 is a perspective view illustrating only the main parts of a plurality of components of a lighting device 100. Fig. 2 is a side cross-sectional view of the lighting device 100.

[0012] 1 , the illumination device 100 includes a light source 3, a first optical system 1, a modulation element 5, and a second optical system 2. The first optical system 1 guides light emitted from the light source 3 to the modulation element 5. The modulation element 5 has an entrance region 500 and an exit region (the rear surface of the entrance region 500), and emits modulated light from the exit region, which has been obtained by dynamically changing the intensity distribution of light incident from the entrance region 500. The second optical system 2 magnifies the modulated light emitted from the exit region of the modulation element 5 and projects it onto an illuminated surface 80 to form a projected image 800.

[0013] The modulation element 5 includes, for example, a liquid crystal panel 51 or a digital micromirror device 52 (see FIG. 7 ). Dynamically changing the intensity distribution of light incident from the incident area 500 by the modulation element 5 corresponds to changing the image displayed by the liquid crystal panel 51 or the digital micromirror device 52. The screen of the liquid crystal panel 51 includes a plurality of pixels, and the liquid crystal panel 51 changes the image displayed on the screen by changing the light transmission characteristics of each of the plurality of pixels. The screen of the digital micromirror device 52 includes a plurality of micromirrors, and the digital micromirror device 52 changes the image displayed on the screen by changing the light reflection characteristics of the plurality of micromirrors.

[0014] The incident area 500 does not necessarily refer to the entire area where a plurality of pixels or a plurality of micromirrors are arranged. Of the area where a plurality of pixels or a plurality of micromirrors are arranged, only the area where light from the light source 3 actually enters is the incident area 500.

[0015] The modulation element 5 (liquid crystal panel 51 or digital micromirror device 52) changes the image to be displayed in accordance with the control of the display switching device C1 (see FIG. 2).

[0016] The modulation element 5 may display a color image or a monochrome image.

[0017] The modulation element 5 displays an image including at least one of a pattern, a figure, and a symbol (such as a letter or a number), for example.

[0018] The modulation element 5 may change the image (still image) to be displayed over time, thereby reproducing a moving image.

[0019] When the modulation element 5 includes a liquid crystal panel 51, light emitted from the light source 3 passes through the liquid crystal panel 51 and is projected onto the irradiated surface 80, thereby displaying an image (projected image 800) on the irradiated surface 80. When the modulation element 5 includes a digital micromirror device 52, light emitted from the light source 3 is reflected by the digital micromirror device 52 and projected onto the irradiated surface 80, thereby displaying an image (projected image 800) on the irradiated surface 80. The projected image 800 is a two-dimensional image. The modulation element 5 dynamically changes the intensity distribution (two-dimensional distribution) of the light incident from the incident region 500, resulting in a dynamic change in the intensity distribution (two-dimensional distribution) of the light in the projected image 800.

[0020] The irradiated surface 80 on which the projected image 800 is formed may be, for example, a surface on a screen, a surface included in a building (exterior wall surface, interior wall surface, floor surface, or ceiling surface, etc.), the ground, or a surface (exterior or interior surface) included in a moving body such as a cart or vehicle.

[0021] (1.2) Problems Figure 2 shows an example of an optical path OP1 of modulated light emitted from a first portion P1 of the emission area of ​​the modulation element 5 to the irradiated surface 80, and an example of an optical path OP2 of modulated light emitted from a second portion P2 of the emission area of ​​the modulation element 5 to the irradiated surface 80.

[0022] Here, assume that the optical axis of the emitted light from the illumination device 100 is oblique to the illuminated surface 80. As a result, as shown in FIG. 2 , the optical path length of the modulated light emitted from a first portion P1 of the emission region of the modulation element 5 to the illuminated surface 80 is longer than the optical path length of the modulated light emitted from a second portion P2 of the emission region of the modulation element 5 to the illuminated surface 80. The modulated light emitted from the first portion P1 is more magnified than the modulated light emitted from the second portion P2, resulting in a greater decrease in optical energy density until it reaches the illuminated surface 80. As such, the longer the optical path length from the emission region of the modulation element 5 to the illuminated surface 80, the more the modulated light is magnified, resulting in a greater decrease in optical energy density until it reaches the illuminated surface 80. Therefore, for example, if the optical energy density distribution in the entrance region 500 and the distribution of the optical characteristic (transmittance or reflectance) of the modulation element 5 are uniform, the optical energy density distribution of the projected image 800 will be non-uniform. In other words, unevenness occurs in the brightness of the projected image 800. The optical characteristic referred to here is transmittance when the modulation element 5 includes the liquid crystal panel 51, and is reflectance when the modulation element 5 includes the digital micromirror device 52.

[0023] Furthermore, since the modulated light expands in accordance with the optical path length from the exit region of the modulation element 5 to the illuminated surface 80, if the shape of the entrance region 500 is rectangular, the projected image 800 will be distorted to become trapezoidal (so-called trapezoidal distortion will occur). That is, in this case, the long sides of the trapezoidal projected image 800 are the parts where the optical path length from the exit region is relatively long, and the short sides of the projected image 800 are the parts where the optical path length from the exit region is relatively short.

[0024] (1.3) Solution Therefore, in the lighting device 100 of this embodiment, the shape of the incident region 500 is a trapezoid (isosceles trapezoid). The length of the short side 501 of the incident region 500 is S1, and the length of the long side 502 that is parallel to the short side 501 and longer than the short side 501 is S2. Therefore, the shape of the projected image 800 is a distorted shape of the shape (trapezoid) of the incident region 500. By designing the dimensions of the incident region 500 according to the distance from the exit region to the illuminated surface 80 and the orientation of the illuminated surface 80 with respect to the exit region, the shape of the projected image 800 can be made closer to a rectangular shape.

[0025] Furthermore, in the lighting device 100 of this embodiment, the light energy density D1 on the short side 501 of the incident region 500 is greater than the light energy density D2 on the long side 502 of the incident region 500. In Fig. 1, the light energy density distribution of the incident region 500 is displayed by increasing the dot density in regions of the incident region 500 where the light energy density is greater.

[0026] 2, a first portion P1 of the emission region of the modulation element 5 is a portion facing a short side 501 of the incidence region 500. A second portion P2 of the emission region of the modulation element 5 is a portion facing a long side 502 of the incidence region 500.

[0027] As shown in FIGS. 1 and 2 , modulated light incident on the short side 501 of the incident region 500, where the light energy density is high (D1), travels a relatively long optical path to the illuminated surface 80, resulting in a relatively large decrease in light energy density. On the other hand, modulated light incident on the long side 502 of the incident region 500, where the light energy density is low (D2), travels a relatively short optical path to the illuminated surface 80, resulting in a relatively small decrease in light energy density. Therefore, when the modulation element 5 includes a liquid crystal panel 51, assuming that the transmittance of the modulation element 5 at the short side 501 is equal to the transmittance at the long side 502, the difference in light energy density at the illuminated surface 80 between the modulated light arriving from the short side 501 of the incident region 500 and the modulated light arriving from the long side 502 of the incident region 500 is small. In this way, by making D1 larger than D2, the uniformity of the light energy density distribution of the projected image 800 can be improved.

[0028] Also, for example, if the transmittance at the short side 501 of the modulation element 5 is greater than the transmittance at the long side 502, the area of ​​the projected image 800 corresponding to the short side 501 will be displayed brightly, and the area corresponding to the long side 502 will be displayed darkly.

[0029] That is, just as in the case where a projection image without trapezoidal distortion is formed by irradiating the modulation element 5 with light having a uniform light energy density distribution, the lighting device 100 of this embodiment also has a distribution of light and dark in the projection image 800 that corresponds to the optical characteristics (transmittance or reflectance) of each region of the modulation element 5. The optical characteristics referred to here are transmittance when the modulation element 5 includes the liquid crystal panel 51, and reflectance when the modulation element 5 includes the digital micromirror device 52.

[0030] In this way, the lighting device 100 of this embodiment can correct trapezoidal distortion in the projected image 800 while more accurately reflecting the optical characteristics of each region of the modulation element 5 in the distribution of light and dark (light energy density) in the projected image 800.

[0031] (1.4) Process for Forming a Projected Image Hereinafter, a process for forming a projected image 800 by the illumination device 100 of this embodiment will be described with reference to FIG.

[0032] The display switching device C1 of the lighting device 100 receives an illumination pattern command. The illumination pattern command is generated, for example, by an input signal generating unit C3 provided outside the lighting device 100. The illumination pattern command specifies the shape, dimensional ratio, light energy density distribution, color distribution, etc. of the projection image 800. The input signal generating unit C3 inputs, for example, an image signal IM1 representing the projection image 800 to the display switching device C1 as the illumination pattern command. Note that the lighting device 100 may be provided with the input signal generating unit C3.

[0033] As a simple example, a case will be described in which the input signal generating unit C3 generates an image signal IM1 representing a rectangular projection image 800 as an illumination pattern command, as shown in Figure 3. In the image signal IM1, the light energy density on the four sides of the rectangle (first region R1) is a first light energy density, and the light energy density inside (second region R2) and outside (third region R3) of the first region R1 is a second light energy density that is smaller than the first light energy density. In the first region R1, the light energy density is constant (first light energy density). Inside and outside the first region R1, the light energy density is constant (second light energy density).

[0034] Based on the illumination pattern command, the display switching device C1 generates a video input signal that specifies an image to be displayed on the liquid crystal panel 51, and outputs the video input signal to the liquid crystal panel 51. The transmittance distribution of the liquid crystal panel 51 changes in response to the video input signal. Here, the transmittance distribution of the liquid crystal panel 51 is not a distribution that directly copies the pattern of the image signal IM1 that serves as the illumination pattern command, but rather a distribution in which the width of the lower side (a portion with a relatively long optical path length) of the image signal IM1 is narrower than that of the upper side (a portion with a relatively short optical path length) in order to correct keystone distortion of the projected image 800. In Figure 3, the dot density is shown to be greater in areas with higher transmittance.

[0035] The transmittance distribution of the liquid crystal panel 51 reflects the light energy density distribution of the image signal IM1. Therefore, the transmittance of the portion (fourth region R4) of the liquid crystal panel 51 corresponding to the four sides (first region R1) of the rectangle of the image signal IM1 is a first transmittance, and the transmittance inside and outside the fourth region R4 is a second transmittance that is smaller than the first transmittance. In the fourth region R4, the transmittance is constant (first transmittance). In the inside and outside of the fourth region R4, the transmittance is constant (second transmittance).

[0036] Furthermore, incident light B1 is irradiated onto the liquid crystal panel 51 having the transmittance distribution set in this manner, as shown in Fig. 3. The incident light B1 that has passed through the liquid crystal panel 51 is output as emitted light B2 from the lighting device 100. In Fig. 3, the dot density is shown to be greater in areas of the incident light B1 and the emitted light B2 where the light energy density is greater.

[0037] The light energy density distribution of the incident light B1 is greater on the lower side (part where the light path length is relatively long) than on the upper side (part where the light path length is relatively short).

[0038] The incident light B1 passes through the fourth region R4 of the liquid crystal panel 51, but is hardly transmitted through the fifth region R5 and the sixth region R6. Therefore, the shape of the outgoing light B2 corresponds to the shape of the fourth region R4.

[0039] As shown in Figure 3, when the transmittance of the fourth region R4 of the liquid crystal panel 51 is constant, the light energy density distribution of the outgoing light B2 is larger on the lower side (the part with a relatively long optical path length) than on the upper side (the part with a relatively short optical path length), similar to the incident light B1.

[0040] The emitted light B2 is projected as the projection image 800, which reflects the shape, dimensional ratio, light energy density distribution, color distribution, etc. of the image signal IM1 serving as the illumination pattern command. In this way, the illumination device 100 of this embodiment can precisely control the light energy density distribution of the projection image 800 to the desired distribution input as the image signal IM1.

[0041] (2) Details The lighting device 100 of this embodiment will be described in more detail below.

[0042] (2.1) Overall Configuration As described above, the illumination device 100 includes the light source 3, the first optical system 1, the modulation element 5, and the second optical system 2. As shown in Fig. 2, the illumination device 100 preferably further includes a first polarizing plate 61, a diaphragm 4, a second polarizing plate 62, a substrate 300, a main body 7, a display switching device C1, and a control device C2.

[0043] The first polarizer 61, the diaphragm 4, the modulation element 5 (liquid crystal panel 51), and the second polarizer 62 constitute the liquid crystal display 6. In other words, the lighting device 100 includes the liquid crystal display 6.

[0044] (2.2) Main Body The main body 7 has a housing 71 and a support member 72 .

[0045] The housing 71 houses the light source 3, the first optical system 1, the modulation element 5, the second optical system 2, the first polarizer 61, the aperture 4, the second polarizer 62, the substrate 300, the display switching device C1, and the control device C2.

[0046] The support member 72 supports the housing 71. The support member 72 is installed, for example, on the floor or the ground. The support member 72 preferably rotatably supports the housing 71. By rotating the housing 71, the lighting device 100 can change the direction in which light is emitted.

[0047] (2.3) Light Source and Substrate As shown in Fig. 4, the light source 3 is mounted on, for example, a substrate 300. The light source 3 has one or more (24 in Fig. 4) light-emitting elements 31. Each light-emitting element 31 emits light (visible light). Each light-emitting element 31 is, for example, a light-emitting diode element or a laser diode element. The light emitted by each light-emitting element 31 is, for example, white.

[0048] When the light source 3 has two or more light-emitting elements 31, the two or more light-emitting elements 31 preferably include a plurality of light-emitting elements 31 each having a different intensity of emitted light.

[0049] Furthermore, it is preferable that the intensity of the emitted light from the light-emitting elements 31, among the plurality of light-emitting elements 31, arranged in a region that emits light to the short side 501 of the entrance region 500 (see FIG. 1 ) of the modulation element 5 is greater than the intensity of the emitted light from the light-emitting elements 31, among the plurality of light-emitting elements 31, arranged in a region that emits light to the long side 502 of the entrance region 500. This makes it easier for the light energy density D1 on the short side 501 of the entrance region 500 to be greater than the light energy density D2 on the long side 502.

[0050] In Fig. 4, 24 light-emitting elements 31 are arranged in 6 rows and 4 columns. In the following description, the light-emitting elements 31 in the first, second, third, fourth, fifth, and sixth rows from the bottom will also be referred to as light-emitting elements 31a, 31b, 31c, 31d, 31e, and 31f, respectively. In each row, four light-emitting elements 31 are arranged side by side. The number of rows and columns may be changed as appropriate.

[0051] The light source 3 and the modulation element 5 are aligned in the Y-axis direction, and the optical axis of the emitted light from each light-emitting element 31 is aligned along the Y-axis direction.

[0052] Light-emitting element 31a is arranged in an area that emits light toward short side 501 of incident area 500. Light-emitting element 31f is arranged in an area that emits light toward long side 502 of incident area 500. Therefore, it is preferable that the intensity of the light emitted from light-emitting element 31a is greater than the intensity of the light emitted from light-emitting element 31f.

[0053] As an example, the intensity of light emitted from each of the light-emitting elements 31a and 31b is a first intensity, the intensity of light emitted from each of the light-emitting elements 31c and 31d is a second intensity, and the intensity of light emitted from each of the light-emitting elements 31e and 31f is a third intensity. The first intensity is greater than the second intensity, and the second intensity is greater than the third intensity. In this way, it is preferable that the light-emitting element 31 located further downward has a higher intensity of emitted light. In other words, it is preferable that the light-emitting element 31 that emits light to a position closer to the short side 501 of the incident region 500 has a higher intensity of emitted light.

[0054] (2.4) First Optical System As shown in FIG. 2, the first optical system 1 includes, for example, a lens unit 11 and a diffusion sheet 12.

[0055] The lens unit 11 includes a plurality of lenses 110. Each of the plurality of lenses 110 is a collimator lens. As an example, the plurality of lenses 110 are connected to one another. In other words, as an example, the lens unit 11 is a lens array. The lens unit 11 is, for example, a resin molded product made of a resin material such as polymethyl methacrylate resin.

[0056] The plurality of lenses 110 are disposed in the optical path between the light source 3 and the diffusion sheet 12. The plurality of lenses 110 face the plurality of light-emitting elements 31. The plurality of lenses 110 distribute the light emitted from the plurality of light-emitting elements 31, respectively.

[0057] The diffusion sheet 12 is disposed in the optical path between the lens unit 11 and the liquid crystal display 6. The diffusion sheet 12 diffuses the light incident from the lens unit 11.

[0058] (2.5) Liquid Crystal Display The liquid crystal display 6 has a first polarizing plate 61, an aperture stop 4, a modulation element 5, and a second polarizing plate 62. The modulation element 5 includes a liquid crystal panel 51.

[0059] The first polarizing plate 61 is disposed in the optical path between the diffusion sheet 12 and the diaphragm 4. The diaphragm 4 is disposed in the optical path between the first polarizing plate 61 and the liquid crystal panel 51. The liquid crystal panel 51 is disposed in the optical path between the diaphragm 4 and the second polarizing plate 62.

[0060] The direction of the transmission axis of the first polarizer 61 is perpendicular to the direction of the transmission axis of the second polarizer 62. The light transmittance of each pixel of the liquid crystal panel 51 changes depending on the voltage applied to the pixel. The display switching device C1 dynamically changes the voltage applied to each pixel of the liquid crystal panel 51, thereby dynamically changing the intensity distribution of the modulated light emitted from the liquid crystal panel 51.

[0061] The diaphragm 4 has a plate-like shape. The thickness direction of the diaphragm 4 is along the Y-axis direction. As shown in FIG. 1 , the diaphragm 4 has an opening 40. The opening 40 penetrates the diaphragm 4 in the Y-axis direction. The shape of the opening 40 is constant. The opening 40 transmits light. Areas of the diaphragm 4 where the opening 40 is not provided block light.

[0062] That is, the diaphragm 4 is disposed in the optical path between the modulation element 5 and the first optical system 1, and an opening 40 of the diaphragm 4 passes the light emitted from the light source 3.

[0063] The shape of the opening 40 is a trapezoid (isosceles trapezoid) with a short side 401 having a length of L1 and a long side 402 having a length of L2. The long side 402 is parallel to the short side 401 of the opening 40 and is longer than the short side 401 of the opening 40. The short side 401 and the long side 402 are sides along the X-axis (left-right direction), and the short side 401 is located below the long side 402.

[0064] The modulation element 5 has a plate-like shape. The thickness direction of the modulation element 5 is along the Y-axis direction (front-rear direction). The modulation element 5 has a front surface 5a and a rear surface 5b (see FIG. 2). The entrance area 500 of the modulation element 5 is provided on the front surface 5a, and the exit area of ​​the modulation element 5 is provided on the rear surface 5b. The shape of the entrance area 500 is the same as the shape of the exit area.

[0065] The entrance region 500 of the modulation element 5 is an area into which the light emitted from the light source 3 is incident. The range of the light emitted from the light source 3 that is incident on the entrance region 500 is limited depending on the shape of the opening 40. Specifically, the shape of the entrance region 500 is the same as the shape of the opening 40. As described above, since the shape of the opening 40 is trapezoidal, the shape of the entrance region 500 is also trapezoidal.

[0066] The length S1 of the short side 501 of the incident area 500 is equal to the length L1 of the short side 401 of the opening 40. The length S2 of the long side 502 of the incident area 500 is equal to the length L2 of the long side 402 of the opening 40. The short side 501 and the long side 502 are sides along the X-axis (left-right direction), and the short side 501 is located below the long side 502.

[0067] As described above, D1, which is the light energy density on the short side 501 of the incident region 500, is greater than D2, which is the light energy density on the long side 502 of the incident region 500. Furthermore, in the incident region 500, the light energy density is greater closer to the short side 501, and the light energy density is smaller closer to the long side 502. In other words, in the incident region 500, the light energy density is smaller on the upper side (positive side of the Z axis).

[0068] (2.6) Second Optical System The second optical system 2 is configured as an oblique imaging optical system. One or more optical components (one in FIG. 2) of the second optical system 2 are arranged approximately according to the Scheimpflug principle.

[0069] The second optical system 2 has a projection lens 21 as an optical component. The modulated light emitted from the emission region of the modulation element 5 passes through the second polarizing plate 62 and enters the projection lens 21. The projection lens 21 magnifies the modulated light and projects it onto the illuminated surface 80, thereby forming a projected image 800 on the illuminated surface 80. In other words, the projected image 800 is larger than the emission region and the entrance region 500.

[0070] 2 , the optical path OP1 of the modulated light emitted from the first portion P1 (the portion opposite the short side 501) of the emission region of the modulation element 5 to the irradiated surface 80 is longer than the optical path OP2 of the modulated light emitted from the second portion P2 (the portion opposite the long side 502) to the irradiated surface 80. Therefore, the attenuation rate of the modulated light passing through the optical path OP1 is greater than the attenuation rate of the modulated light passing through the optical path OP2. Here, the attenuation rate is the difference between the optical energy density in the emission region of the modulation element 5 and the optical energy density on the irradiated surface 80 divided by the optical energy density in the emission region of the modulation element 5.

[0071] It is preferable that the optical paths OP1 and OP2 are designed so that, if the light transmittances of the plurality of pixels of the liquid crystal panel 51 are equal to each other, the light energy density at each position of the projected image 800 on the illuminated surface 80 is within a predetermined range. In other words, if the light transmittances of the plurality of pixels of the liquid crystal panel 51 are equal to each other, it is preferable that the light energy density at each position of the projected image 800 on the illuminated surface 80 is approximately equal to each other.

[0072] (2.7) Display Switching Device The display switching device C1 controls the modulation element 5 to change the image displayed by the modulation element 5. More specifically, the display switching device C1 dynamically changes the voltage applied to each pixel of the liquid crystal panel 51 of the modulation element 5, thereby dynamically changing the intensity distribution of the modulated light emitted from the modulation element 5.

[0073] The display switching device C1 includes, for example, an application circuit that applies a voltage to a plurality of pixels of the liquid crystal panel 51, and a voltage control circuit that controls the application circuit.

[0074] In addition, when the modulation element 5 includes a digital micromirror device 52 (see Figure 7), the display switching device C1 can dynamically change the intensity distribution of the modulated light emitted from the modulation element 5 by driving multiple micromirrors of the digital micromirror device 52.

[0075] (2.8) Control Device The control device C2 controls the emission direction of modulated light emitted from the modulation element 5. The control device C2 controls the emission direction of the modulated light, for example, by changing the orientation of the housing 71. Alternatively, the control device C2 controls the emission direction of the modulated light, for example, by changing the arrangement (position and / or orientation) of at least one of the light source 3, the first optical system 1, the diaphragm 4, the modulation element 5, and the second optical system 2.

[0076] The control device C2 has, for example, a driving mechanism that displaces at least one of the housing 71, the light source 3, the first optical system 1, the aperture 4, the modulation element 5, and the second optical system 2, and an operation control circuit that controls the operation of the driving mechanism.

[0077] 1, H1, which is the maximum vertical length of the projected image 800 on the illuminated surface 80, is longer than W1, which is the maximum horizontal length of the projected image 800 on the illuminated surface 80. Furthermore, 2×W1≦H1 holds. Furthermore, the shape of the projected image 800 on the illuminated surface 80 is rectangular. In other words, the control device C2 controls the emission direction of the modulated light so that such a projected image 800 is formed.

[0078] More specifically, if multiple pixels of the liquid crystal panel 51 constituting the modulation element 5 are in the on state (transmitting light) at the trapezoidal peripheral portion of the entrance area 500 of the modulation element 5, where light passing through the aperture 4 is incident, the shape of the projected image 800 on the irradiated surface 80 will be rectangular.

[0079] The horizontal direction refers to a direction parallel to the projected image 800 and perpendicular to the optical axis of the light emitted from the lighting device 100 to the illuminated surface 80. The vertical direction refers to a direction parallel to the projected image 800 and perpendicular to the horizontal direction.

[0080] In the present disclosure, the range of the projected image 800 is defined as follows: When the projected image 800 is formed in a dark place, the range of the projected image 800 is the range of brightness that is 10% or more of the brightest part of the projected image 800. H1 and W1 are defined based on this definition.

[0081] (2.9) Conditions Related to the Illumination Device Below are listed conditions that the illumination device 100 should preferably satisfy. It is preferable that the illumination device 100 satisfies one or more of the following conditions, and it is most preferable that the illumination device 100 satisfies all of the following conditions.

[0082] First, conditions relating to S1, which is the length of the short side 501 of the incident area 500, S2, which is the length of the long side 502, D1, which is the light energy density on the short side 501, and D2, which is the light energy density on the long side 502 will be described.

[0083] It is preferable that S2 / S1 is equal to D1 / D2. This allows the optical characteristics (transmittance or reflectance) of each region of the modulation element 5 to be more accurately reflected in the light energy density distribution of the projected image 800. Here, "equal" does not necessarily mean that the difference between the two values ​​is strictly zero, but may also mean that the difference between the two values ​​is less than 10% of either of the larger values, for example.

[0084] It is also preferable that 2×S1≦S2 be satisfied. It is also preferable that 2×D2≦D1 be satisfied. This makes it possible to correct keystone distortion even when the keystone distortion of the projected image 800 is relatively large.

[0085] Furthermore, if the shape of the projected image 800 is a rectangle with a horizontal length of W1, the projection magnifications are defined as β1=W / S1 and β2=W / S2. Due to the above condition 2×S1≦S2, it is preferable that β1≧2×β2 be satisfied.

[0086] Next, conditions relating to L1, which is the length of the short side 401 of the opening 40 of the diaphragm 4, and L2, which is the length of the long side 402, will be described.

[0087] It is preferable that 2×L1≦L2 be satisfied, whereby even when the trapezoidal distortion of the projected image 800 is relatively large, the trapezoidal distortion can be corrected.

[0088] Furthermore, it is preferable that L2 / L1 is equal to D1 / D2. This allows the optical characteristics (transmittance or reflectance) of each region of the modulation element 5 to be more accurately reflected in the light energy density distribution of the projected image 800. Here, "equal" does not necessarily mean that the difference between the two values ​​is strictly zero, but may also mean that the difference between the two values ​​is less than 10% of either of the larger values, for example.

[0089] (Embodiment 2) Hereinafter, a description will be given of embodiment 2. The same components as those in embodiment 1 will be given the same reference numerals and the description will be omitted.

[0090] As shown in FIG. 5, in an illumination device 100A according to the second embodiment, the configuration of a light source 3A is different from that of the light source 3 according to the first embodiment.

[0091] The light source 3A has a plurality of light-emitting elements 31. The intensities of the emitted light from the plurality of light-emitting elements 31 may be equal to each other, or the intensities of the emitted light from at least some of the light-emitting elements 31 may be different from the intensities of the emitted light from the other light-emitting elements 31.

[0092] The light source 3A and the modulation element 5 are aligned in the front-to-rear direction, and the optical axis of the emitted light from each light-emitting element 31 is aligned in the front-to-rear direction.

[0093] In Fig. 5, a plurality of light-emitting elements 31 are arranged in six rows in the vertical direction. In the first row from the bottom, five light-emitting elements 31a are arranged horizontally. In the second row from the bottom, five light-emitting elements 31b are arranged horizontally. In the third row from the bottom, four light-emitting elements 31c are arranged horizontally. In the fourth row from the bottom, four light-emitting elements 31d are arranged horizontally. In the fifth row from the bottom, three light-emitting elements 31e are arranged horizontally. In the sixth row from the bottom, three light-emitting elements 31f are arranged horizontally.

[0094] The number of rows and the number of light-emitting elements 31 in each row may be changed as appropriate.

[0095] The five light emitting elements 31 a located first from the bottom are arranged in an area that emits light toward the short side 501 of the incident area 500 .

[0096] The sixth three light emitting elements 31 f from the bottom are arranged in an area that emits light toward the long side 502 of the incident area 500 .

[0097] The first five light-emitting elements 31a from the bottom are arranged more densely than the third three light-emitting elements 31f from the bottom. That is, the first row from the bottom has more light-emitting elements 31 per unit area than the sixth row from the bottom. Also, the distance between the light-emitting elements 31a in the first row from the bottom is smaller than the distance between the light-emitting elements 31f in the sixth row from the bottom.

[0098] In this manner, the plurality of light-emitting elements 31 of this embodiment are arranged more densely in the region that emits light to the short side 501 of the entrance region 500 of the modulation element 5 than in the region that emits light to the long side 502 of the entrance region 500 of the modulation element 5. This makes it easier for the optical energy density D1 on the short side 501 of the entrance region 500 to be greater than the optical energy density D2 on the long side 502.

[0099] Furthermore, the plurality of light-emitting elements 31 are arranged more densely in the entire area where the plurality of light-emitting elements 31 are arranged, the closer they are to the area that emits light to the short side 501. In other words, the number of light-emitting elements 31 per unit area increases as they are closer to the area that emits light to the short side 501 in the entire area where the plurality of light-emitting elements 31 are arranged.

[0100] As in the first embodiment, the intensity of emitted light from the light emitting elements 31 arranged in a region that emits light to the short side 501 of the entrance region 500 of the modulation element 5 may be greater than the intensity of emitted light from the light emitting elements 31 arranged in a region that emits light to the long side 502 of the entrance region 500. Furthermore, the lower the light emitting elements 31 arranged, the greater the intensity of emitted light may be.

[0101] (Embodiment 3) Hereinafter, a description will be given of embodiment 3. The same components as those in embodiment 1 will be denoted by the same reference numerals and the description will be omitted.

[0102] As shown in FIG. 6, in an illumination device 100B according to the third embodiment, the configurations of a light source 3B and a first optical system 1B are different from those of the light source 3 and the first optical system 1 of the first embodiment.

[0103] The illumination device 100B includes a light generation unit G1, a light distribution unit U1, a liquid crystal display 6, and a second optical system 2. The configurations of the liquid crystal display 6 and the second optical system 2 are the same as those in embodiment 1. The light generation unit G1 has a light source 3B and emits white light to the light distribution unit U1. The first optical system 1B includes the configuration of the light generation unit G1 excluding the light source 3B, and the light distribution unit U1.

[0104] The light source 3B has a plurality of (two in FIG. 6) laser diodes 32. Each of the laser diodes 32 is a blue laser diode.

[0105] The light generation unit G1 includes a light source 3B, a diffusion sheet 901, a dichroic mirror 902, condenser lenses 903 and 904, a phosphor device 905, condenser lenses 906 and 907, and a diffuse reflection mirror 908.

[0106] 6, the dotted lines extending from each laser diode 32 represent the optical path of the blue laser light emitted from each laser diode 32. The dashed lines extending from phosphor device 905 represent the optical path of light generated from phosphor device 905 when phosphor device 905 is irradiated with blue laser light.

[0107] The blue laser light emitted from each laser diode 32 is diffused by a diffusion sheet 901 and then reaches a dichroic mirror 902. A portion of this blue laser light is reflected by the dichroic mirror 902, collected by condenser lenses 906 and 907, reflected by a diffuse reflection mirror 908, transmitted through the dichroic mirror 902, and emitted to the light distribution unit U1. Another portion of the blue laser light is transmitted through the dichroic mirror 902, collected by condenser lenses 903 and 904, and reaches the phosphor device 905. The phosphor device 905 absorbs the blue laser light and emits light of a predetermined color. The predetermined color is, for example, yellow light. The light emitted from the phosphor device 905 is reflected by the dichroic mirror 902 and emitted to the light distribution unit U1.

[0108] Therefore, the light generating unit G1 outputs the blue laser light and the light emitted from the phosphor device 905 to the light distribution unit U1 with their optical axes aligned.

[0109] The light distribution unit U1 has integrator lens arrays 13 and 14, a polarizing beam splitter 15, and a condenser lens 16. The light emitted from the light generation unit G1 passes through the integrator lens arrays 13 and 14, the polarizing beam splitter 15, and the condenser lens 16, and is emitted to the liquid crystal display 6.

[0110] The lighting device 100B includes the light distribution unit U1, thereby improving light utilization efficiency and contrast, although it is not essential that the lighting device 100B includes the light distribution unit U1.

[0111] Furthermore, a white light emitting diode may be used as the light generating unit G1.

[0112] (Embodiment 4) Hereinafter, a description will be given of embodiment 4. The same components as those in embodiment 1 will be denoted by the same reference numerals and the description will be omitted.

[0113] As shown in FIG. 7, in an illumination device 100C according to the fourth embodiment, the configurations of a modulation element 5C, a light source 3C, and a first optical system 1C are different from those of the modulation element 5, the light source 3, and the first optical system 1 of the first embodiment.

[0114] The illumination device 100C includes a light generation unit G2, a light distribution unit U2, a modulation element 5C, and a second optical system 2. The configuration of the second optical system 2 is the same as in embodiment 1. The modulation element 5C includes a digital micromirror device 52. The light generation unit G2 has a light source 3C and emits white light to the digital micromirror device 52. The first optical system 1C includes the configuration of the light generation unit G2 excluding the light source 3C, and a light distribution unit U2.

[0115] The light source 3C has a plurality of (two in FIG. 7) laser diodes 32. Each of the laser diodes 32 is a blue laser diode.

[0116] The light generation unit G2 has a light source 3C, a diffusion sheet 911, a dichroic mirror 912, condensing lenses 913 and 914, a phosphor wheel 915, a collimating lens 916, mirrors 917 and 918, a relay lens 919, a diffusion sheet 920, a mirror 921, a condensing lens 922, a filter wheel 923, an integrator rod 924, and a collimating lens 925 (collimator lens).

[0117] 7 , dotted lines extending from each laser diode 32 toward the diffusion sheet 911 represent the optical paths of the blue laser light emitted from each laser diode 32. Two dashed lines extending from the phosphor wheel 915 toward the condenser lens 913 represent the optical paths of light generated from the phosphor wheel 915 when the phosphor wheel 915 is irradiated with the blue laser light. Three thin lines extending from the filter wheel 923 toward the integrator rod 924 represent the optical paths of the light emitted from the filter wheel 923 to the integrator rod 924.

[0118] The blue laser light emitted from each laser diode 32 is diffused by a diffusion sheet 911 , passes through a dichroic mirror 912 , is condensed by condenser lenses 913 and 914 , and is then irradiated onto a phosphor wheel 915 .

[0119] The phosphor wheel 915 is configured, for example, by providing a phosphor layer on the surface of a circular aluminum substrate. A rotary motor is disposed in the center of the aluminum substrate, and the rotary motor rotates the phosphor wheel 915. The phosphor wheel 915 is irradiated with blue laser light, exciting the phosphor layer, which then emits yellow light containing green and red wavelength components. The yellow light emitted from the phosphor wheel 915 is reflected by the dichroic mirror 912, condensed by the condenser lens 922, and reaches the filter wheel 923.

[0120] In addition, the blue laser light that passes through the phosphor wheel 915 passes through the collimator lens 916, mirrors 917 and 918, relay lens 919, diffusion sheet 920, and mirror 921, passes through the dichroic mirror 912, is focused by the focusing lens 922, and reaches the filter wheel 923.

[0121] The yellow light and blue laser light incident on the filter wheel 923 are separated by the filter wheel 923 into red light, green light, blue light, and yellow light, and are output to the integrator rod 924 .

[0122] The integrator rod 924 is a solid rod made of a transparent material such as glass. The integrator rod 924 generates light with a uniform intensity distribution by internally reflecting incident light multiple times. Note that the integrator rod 924 may also be a hollow rod with an inner wall made of a mirror surface.

[0123] The light emitted from the integrator rod 924 passes through a collimator lens 925 and is emitted to the light distribution unit U2.

[0124] The light distribution unit U2 has a condenser lens 17 and a mirror 18. The light emitted from the light generation unit G2 passes through the condenser lens 17 and the mirror 18 and is emitted to the digital micromirror device 52. The digital micromirror device 52 emits the light reflected by the multiple micromirrors to the second optical system 2.

[0125] The digital micromirror device 52 can emit a color of desired chromaticity coordinates to the second optical system 2 by adjusting the on-time and off-time of each of the multiple micromirrors.

[0126] The diaphragm 4 (see FIG. 1) may be disposed between the digital micromirror device 52 and the light distribution unit U2.

[0127] (Modifications of the Third and Fourth Embodiments) Modifications of the third and fourth embodiments will be described below.

[0128] 8 shows the configuration of the light generation unit G3 of this modified example. The light generation unit G1 of the third embodiment may be replaced with the light generation unit G3 of this modified example. Furthermore, the light generation unit G2 of the fourth embodiment may be replaced with the light generation unit G3 of this modified example.

[0129] In FIG. 8, three thin lines extending from the light source 3D represent the optical paths of the light emitted from the light source 3D.

[0130] The light generation unit G3 has a light source 3D, a lens array 931, a condenser lens 932, a diffusion sheet 933, an integrator rod 934, and a collimator lens 935. The lens array 931, the condenser lens 932, the diffusion sheet 933, the integrator rod 934, and the collimator lens 935 are included in the first optical system 1B (see FIG. 6) or the first optical system 1C (see FIG. 7).

[0131] The light source 3D includes a blue laser diode, a green laser diode, and a red laser diode, and therefore emits blue light, green light, and red light.

[0132] Light emitted from the light source 3D passes through a lens array 931, a condenser lens 932, a diffusion sheet 933, an integrator rod 934, and a collimator lens 935, and is emitted to the modulation element 5 or 5C. A light distribution unit U1 (see FIG. 6) may be arranged in the optical path between the light generation unit G3 and the modulation element 5. Furthermore, a light distribution unit U2 (see FIG. 7) may be arranged in the optical path between the light generation unit G3 and the modulation element 5C.

[0133] According to this modification, the light generation unit G3 has a simple configuration, and has the effect of being capable of full-color output.

[0134] (Other Modifications of Embodiments 1 to 4) Other modifications of Embodiments 1 to 4 are listed below. The following modifications may be realized in appropriate combination. Furthermore, the following modifications may be realized in appropriate combination with one or more of the modifications described above. Hereinafter, the configuration of the above-described embodiment 1 will be referred to as the basic example.

[0135] The light emitted by the light source 3 is not limited to visible light, but may be, for example, infrared light.

[0136] In the basic example, the short side 501 of the incident area 500 is located below the long side 502. However, the positional relationship between the short side 501 and the long side 502 is not limited to the positional relationship in the basic example. For example, the short side 501 may be located above, to the left, or to the right of the long side 502.

[0137] In the basic example, the illumination device 100 is provided with the diaphragm 4, which causes the shape of the incident region 500 to be trapezoidal. However, it is not essential that the illumination device 100 is provided with the diaphragm 4. For example, the shape of the incident region 500 may be trapezoidal by arranging a plurality of pixels of the liquid crystal panel 51 of the modulation element 5 or a plurality of micromirrors of the digital micromirror device 52 of the modulation element 5 in a trapezoidal shape. Alternatively, the light emitted from the light source 3 may be distributed in a trapezoidal shape by an optical element.

[0138] The multiple components that are integrated into one housing 71 in the basic example may be distributed among multiple housings. For example, the housing that houses the light source 3 may be provided separately from the housing that houses the modulation element 5.

[0139] (Summary) The above-described embodiments and the like disclose the following aspects.

[0140] An illumination device (100; 100A: 100B; 100C) according to a first aspect includes a light source (3; 3A; 3B; 3C; 3D), a first optical system (1; 1B; 1C), a modulation element (5; 5C), and a second optical system (2). The first optical system (1; 1B; 1C) guides light emitted from the light source (3; 3A; 3B; 3C; 3D) to the modulation element (5; 5C). The modulation element (5; 5C) has an entrance region (500) and an exit region, and emits modulated light from the exit region, which has dynamically changed the intensity distribution of light incident from the entrance region (500). The second optical system (2) magnifies the modulated light emitted from the exit region of the modulation element (5; 5C) and projects it onto an illuminated surface (80) to form a projected image (800). The shape of the incident area (500) is a trapezoid with a short side (501) having a length S1 and a long side (502) having a length S2 that is parallel to and longer than the short side (501). D1, which is the light energy density on the short side (501) of the incident area (500), is greater than D2, which is the light energy density on the long side (502) of the incident area (500).

[0141] The above configuration has the effect of enabling the light energy density distribution of the projected image (800) to be controlled to a desired distribution with high precision.

[0142] In addition, in the lighting device (100; 100A: 100B; 100C) according to the second aspect, in the first aspect, S2 / S1 is equal to D1 / D2.

[0143] The above configuration has the effect of enabling the light energy density distribution of the projected image (800) to be controlled to a desired distribution with high precision.

[0144] In addition, in the lighting device (100; 100A: 100B; 100C) according to the third aspect, in the first or second aspect, 2×S1≦S2 holds true.

[0145] According to the above configuration, even when the trapezoidal distortion of the projected image (800) is relatively large, the trapezoidal distortion can be corrected.

[0146] Furthermore, in the lighting device (100; 100A: 100B; 100C) according to the fourth aspect, in any one of the first to third aspects, 2×D2≦D1 holds.

[0147] According to the above configuration, even when the trapezoidal distortion of the projected image (800) is relatively large, the trapezoidal distortion can be corrected.

[0148] In addition, in the illumination device (100; 100A: 100B; 100C) according to the fifth aspect, in any one of the first to fourth aspects, H1, which is the maximum vertical length of the projected image (800) on the irradiated surface (80), is longer than W1, which is the maximum horizontal length of the projected image (800) on the irradiated surface (80).

[0149] The above configuration has the advantage that it is possible to form a vertically long projected image (800) while accurately controlling the light energy density distribution of the projected image (800) to a desired distribution.

[0150] In addition, in the lighting device (100; 100A: 100B; 100C) according to the sixth aspect, in the fifth aspect, 2×W1≦H1 holds.

[0151] The above configuration has the advantage that it is possible to form a vertically long projected image (800) while accurately controlling the light energy density distribution of the projected image (800) to a desired distribution.

[0152] In addition, in the illumination device (100; 100A: 100B; 100C) according to the seventh aspect, in the fifth or sixth aspect, the shape of the projected image (800) on the illuminated surface (80) is rectangular.

[0153] The above configuration has the advantage that it is possible to form a vertically long rectangular projected image (800) while accurately controlling the light energy density distribution of the projected image (800) to a desired distribution.

[0154] Furthermore, the lighting device (100; 100A: 100B; 100C) according to an eighth aspect is any one of the first to seventh aspects, and further includes a control device (C2) that controls the emission direction of the modulated light.

[0155] The above configuration has the advantage that the position of the projected image (800) can be controlled.

[0156] Furthermore, the lighting device (100; 100A: 100B; 100C) according to a ninth aspect is any one of the first to eighth aspects, further comprising a diaphragm (4) arranged in the optical path between the modulation element (5; 5C) and the first optical system (1; 1B; 1C). The diaphragm (4) has an opening (40) through which light emitted from the light source (3; 3A; 3B; 3C; 3D) passes. The shape of the opening (40) is trapezoidal, with a short side (401) having a length of L1 and a long side (402) that is parallel to the short side (401) of the opening (40) and longer than the short side (401) of the opening (40) having a length of L2.

[0157] According to the above configuration, it is possible to increase the difference in brightness between the projected image (800) and the area outside the projected image (800), which has the effect of making the projected image (800) clearer.

[0158] In addition, in the lighting device (100; 100A: 100B; 100C) according to the tenth aspect, in the ninth aspect, 2×L1≦L2 holds.

[0159] According to the above configuration, even when the trapezoidal distortion of the projected image (800) is relatively large, the trapezoidal distortion can be corrected.

[0160] In addition, in the lighting device (100; 100A: 100B; 100C) according to the eleventh aspect, in the ninth or tenth aspect, L2 / L1 is equal to D1 / D2.

[0161] The above configuration has the effect of enabling the light energy density distribution of the projected image (800) to be controlled to a desired distribution with high precision.

[0162] In addition, in the lighting device (100; 100A: 100B; 100C) according to a twelfth aspect, in any one of the first to eleventh aspects, the modulation element (5; 5C) includes a liquid crystal panel (51) or a digital micromirror device (52).

[0163] The above configuration has the advantage that the modulation element (5; 5C) can be procured relatively easily.

[0164] In addition, in the lighting device (100) according to a thirteenth aspect, in any one of the first to twelfth aspects, the light source (3) has a plurality of light-emitting elements (31) each having a different intensity of emitted light. The intensity of emitted light of the light-emitting element (31) arranged in a region that emits light to a short side (501) of the incident region (500) is greater than the intensity of emitted light of the light-emitting element (31) arranged in a region that emits light to a long side (502) of the incident region (500).

[0165] The above configuration has the effect that the light energy density on the short side (501) of the incident area (500) tends to be greater than the light energy density on the long side (502).

[0166] In addition, in the lighting device (100A) according to a fourteenth aspect, in any one of the first to thirteenth aspects, the light source (3A) has a plurality of light-emitting elements (31). The plurality of light-emitting elements (31) are arranged more densely in a region that emits light to a short side (501) of the incident region (500) of the modulation element (5; 5C) than in a region that emits light to a long side (502) of the incident region (500) of the modulation element (5; 5C).

[0167] The above configuration has the effect that the light energy density on the short side (501) of the incident area (500) tends to be greater than the light energy density on the long side (502).

[0168] The configurations other than those of the first aspect are not essential for the lighting device (100; 100A: 100B; 100C) and can be omitted as appropriate.

[0169] 1; 1B; 1C First optical system 2 Second optical system 3; 3A; 3B; 3C; 3D Light source 31 Light-emitting element 4 Aperture 5; 5C Modulation element 40 Aperture 51 Liquid crystal panel 52 Digital micromirror device 80 Illuminated surface 100; 100A: 100B; 100C Illumination device 401 Short side 402 Long side 500 Incident area 501 Short side 502 Long side 800 Projected image C2 Control device

Claims

1. A lighting device comprising a light source, a first optical system, a modulation element, and a second optical system, wherein the first optical system guides the light emitted from the light source to the modulation element, the modulation element has an incident region and an exit region, and emits modulated light obtained by dynamically changing the intensity distribution of the light incident from the incident region from the exit region, the second optical system forms a projected image obtained by enlarging the modulated light emitted from the exit region of the modulation element and projecting it onto an irradiated surface, the shape of the incident region is a trapezoid with a short side length of S1 and a long side length of S2 that is parallel to the short side and longer than the short side, and the light energy density D1 at the short side of the incident region is greater than the light energy density D2 at the long side of the incident region.

2. S2 / S1 is equal to D1 / D2, the lighting device according to claim 1.

3. 2×S1 ≤ S2 holds, the lighting device according to claim 1 or 2.

4. 2×D2 ≤ D1 holds, the lighting device according to any one of claims 1 to 3.

5. H1, which is the maximum length in the vertical direction of the projected image on the irradiated surface, is longer than W1, which is the maximum length in the horizontal direction of the projected image on the irradiated surface, the lighting device according to any one of claims 1 to 4.

6. 2×W1 ≤ H1 holds, the lighting device according to claim 5.

7. The shape of the projected image on the irradiated surface is rectangular, the lighting device according to claim 5 or 6.

8. Further comprising a control device for controlling the emission direction of the modulated light, the lighting device according to any one of claims 1 to 7.

9. Further comprising a diaphragm disposed in the optical path between the modulation element and the first optical system, the diaphragm having an aperture through which the light emitted from the light source passes, and the shape of the aperture is a trapezoid with a short side length of L1 and a long side length of L2 that is parallel to the short side of the aperture and longer than the short side of the aperture, the lighting device according to any one of claims 1 to 8.

10. 2×L1 ≤ L2 holds, the lighting device according to claim 9.

11. L2 / L1 is equal to D1 / D2, the lighting device according to claim 9 or 10.

12. The modulation element includes a liquid crystal panel or a digital micromirror device, the lighting device according to any one of claims 1 to 11.

13. The light source has a plurality of light-emitting elements with different light emission intensities, and the light emission intensity of the light-emitting element arranged in the region that emits light to the short side of the incident region among the plurality of light-emitting elements is greater than the light emission intensity of the light-emitting element arranged in the region that emits light to the long side of the incident region among the plurality of light-emitting elements. The lighting device according to any one of claims 1 to 12.

14. The light source has a plurality of light-emitting elements, and the plurality of light-emitting elements are arranged more densely in the region that emits light to the short side of the incident region of the modulation element than in the region that emits light to the long side of the incident region of the modulation element. The lighting device according to any one of claims 1 to 13.

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