JP7564482B2 - Fly-eye lens and illumination optical device - Google Patents

Description

This disclosure relates to a fly-eye lens and an illumination optical device.

In conventional fly-eye lens illumination systems, light emitted from a light source is reflected by a reflecting mirror and emitted forward as approximately parallel light, enters a fly-eye lens, and is emitted from each lens of the fly-eye lens toward the irradiation surface. In this fly-eye lens illumination system, a spot image formed by the fly-eye lens is formed on the irradiation surface, and each individual lens illuminates the entire surface of the irradiation surface, resulting in good illumination characteristics with no unevenness in illuminance or chromaticity on the irradiation surface.

Japanese Patent Application Publication No. 05-346557

In recent years, the development of ADB (Adaptive Driving Beam) headlights, which are applied products of spatial modulation elements such as DMD (Digital Micromirror Device), has been attracting attention. The important characteristic of headlights is the illumination distribution, which is required to have a biased distribution such that the center is brighter than the periphery, and this is also required in the configuration of conventional fly-eye lens lighting systems.

Therefore, an object of the embodiment of the present disclosure is to provide a fly-eye lens and an illumination optical device that have an illumination distribution in which the center is brighter than the periphery.

A fly's eye lens according to an embodiment of the present disclosure comprises an input lens assembly in which input lenses are arranged two-dimensionally on the light input surface, and an output lens assembly in which output lenses are arranged two-dimensionally on the light output surface and are arranged optically opposite the input lenses, and has an input side flat region formed of a flat light-transmitting member between at least some or all of the input lenses constituting the input lens assembly, and the output lens assembly has an output side flat region formed of a flat light-transmitting member optically opposite the input side flat region.

Furthermore, a fly's eye lens according to an embodiment of the present disclosure includes an input lens assembly having a plurality of input lenses arranged two-dimensionally on a light input surface and an input-side flat region formed of a flat light-transmitting member on which the input lenses are not arranged, and an output lens assembly having a plurality of output lenses arranged two-dimensionally on a light output surface and an output-side flat region formed of a flat light-transmitting member on which the output lenses are not arranged, the output lenses being formed at positions optically opposed to the input lenses, and the output-side flat region being formed in a region optically opposed to the input-side flat region.

In addition, the illumination optical device according to an embodiment of the present disclosure is configured to include an optical element disposed in the optical path from a light source and converting the light from the light source into approximately parallel light, the fly-eye lens that receives the light from the optical element and outputs it as light with a desired light irradiation intensity distribution, an optical modulation device that receives the light from the fly-eye lens, changes the optical path, and outputs it, and a projection lens that projects the light from the optical modulation device.

The fly-eye lens according to the embodiment of the present disclosure can bias the illumination distribution so that the central region is brighter than the periphery, and can shape the light to be illuminated in a way that is particularly suitable for headlights.
The illumination optical device according to the embodiment of the present disclosure can illuminate a central area brighter than the surrounding area.

FIG. 2 is a perspective view illustrating a schematic relationship between a fly-eye lens and an irradiation region according to an embodiment of the present disclosure. FIG. 2 is a front view illustrating a schematic view of an entrance surface of a fly's eye lens according to an embodiment of the present disclosure. FIG. 2 is a rear view diagrammatically illustrating an exit surface of a fly's eye lens according to an embodiment of the present disclosure. FIG. 1 is a side view diagrammatically illustrating a fly's eye lens according to an embodiment of the present disclosure. FIG. 2B is a cross-sectional view taken along line II of FIG. 2A, which illustrates a fly's eye lens according to an embodiment of the present disclosure. FIG. 2B is a cross-sectional view taken along line II-II of FIG. 2A, which illustrates a fly's eye lens according to an embodiment of the present disclosure. 1 is an explanatory diagram illustrating a schematic relationship between an optical path of light incident on a first input lens of a fly's eye lens according to an embodiment of the present disclosure and an irradiation area. FIG. 10 is an explanatory diagram illustrating a schematic relationship between the optical path of light incident on a second input lens of a fly's eye lens according to an embodiment of the present disclosure and an irradiation area. FIG. FIG. 1 is an explanatory diagram illustrating a schematic relationship between the optical path of light incident on a flat region of a fly's eye lens according to an embodiment of the present disclosure and an irradiation region. FIG. 2 is an explanatory diagram illustrating a schematic diagram of an optical path of parallel light perpendicular to an incident surface that is incident on a fly's eye lens according to an embodiment of the present disclosure, and the relationship between the flat region, the incident lens, and the exit lens. FIG. 1 is an explanatory diagram illustrating a schematic diagram of an optical path of parallel light that is not perpendicular to the incident surface and that is incident on a fly's eye lens according to an embodiment of the present disclosure, and the relationship between the flat region, the incident lens, and the exit lens. 11 is an explanatory diagram illustrating a schematic view of an irradiation area when a second output lens of the fly-eye lens according to the embodiment of the present disclosure is decentered. FIG. FIG. 11 is a perspective view illustrating a fly's eye lens formed of two members according to another embodiment of the present disclosure. FIG. 11 is a perspective view showing a fly's eye lens including a lens group according to another embodiment of the present disclosure and a flat region in which no lenses are arranged. FIG. 7B is an explanatory diagram illustrating a schematic view of an irradiation area of the fly-eye lens of FIG. 7A. 7B is an explanatory diagram illustrating a schematic view of an irradiation area when an output lens of the fly-eye lens in FIG. 7A is decentered; FIG. FIG. 11 is a perspective view showing a fly's-eye lens including a lens group having flat regions between horizontally arranged lenses and flat regions in which no lenses are arranged, according to another embodiment of the present disclosure. FIG. 13 is a perspective view showing a fly's-eye lens configured with a lens group having flat regions between horizontal lenses according to another embodiment of the present disclosure. FIG. 8C is an explanatory diagram illustrating a schematic illumination region of the fly-eye lens of FIGS. 8A and 8B. 1 is a perspective view illustrating a schematic overall configuration of an illumination optical apparatus according to an embodiment of the present disclosure. FIG. 1 is an explanatory diagram illustrating a schematic configuration in which a reflective optical system is used as an optical member of an illumination optical device according to an embodiment of the present disclosure. 11 is an explanatory diagram illustrating a schematic configuration in which another reflective optical system is used as an optical member of an illumination optical device according to an embodiment of the present disclosure. FIG.

Below, an embodiment of the invention will be described with reference to the drawings as appropriate. However, the form described below is intended to embody the technical concept of the present invention, and unless otherwise specified, the present invention is not limited to the following. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation. Furthermore, in the referenced drawings, as an example, the vertical direction of the fly-eye lens is described as the Z direction, the width direction of the fly-eye lens is the X direction, and the thickness direction of the fly-eye lens is the Y direction. Furthermore, the entrance lens assembly of the fly-eye lens is the front.

[Fly-eye lens configuration]
The configuration of the fly's eye lens 10 will be described with reference to FIG. 1 and FIG. 2A to FIG. 2E.
1 and 2A to 2E, the fly-eye lens 10 receives light LB, which is substantially parallel light, from an incident surface 10In and emits it from an exit surface 10Ex, thereby forming a distribution of light irradiation intensity in which the center is brighter than the periphery on an irradiation surface EA irradiated via the condenser lens 50. The irradiation surface EA is a surface onto which light is irradiated by the fly-eye lens 10, and is, for example, an irradiation surface of a light modulation device 70 (see FIG. 9) described below.

The fly-eye lens 10 comprises an input lens assembly 11A in which input lenses 11L are arranged two-dimensionally on an input surface 10In of light LB, and an output lens assembly 12A in which output lenses 12L, which are installed optically opposite the input lenses 11L, are arranged two-dimensionally on an output surface 10Ex of light. The input lens assembly 11A has input-side flat regions 11F formed of a flat light-transmitting member between at least some or all of the input lenses 11L, and the output lens assembly 12A has an output-side flat region 12F optically opposite the input-side flat region 11F and formed of a flat light-transmitting member that transmits light.
The fly-eye lens 10 has an entrance surface 10In and an exit surface 10Ex formed of a light-transmitting member, and an entrance lens assembly 11A and an exit lens assembly 12A are integrally formed.

The input lens assembly 11A has multiple input lens groups, each of which is a group of multiple input lenses with the same lens dimensions, arranged with the lens dimensions changed for each input lens group, and the output lens assembly 12A has multiple output lens groups, each of which corresponds to the input lens groups of the input lens assembly 11A, arranged with the lens dimensions changed for each output lens group.
Here, the input lens assembly 11A has a first input lens group (11L1, 11L1, ...) and a second input lens group (11L2, 11L2, ...) each including a first input lens 11L1 and a second input lens 11L2 having a lens size smaller than that of the first input lens 11L1. Furthermore, the output lens assembly 12A has a first output lens group (12L1, 12L1, ...) and a second output lens group (12L2, 12L2, ...) in which a first output lens 12L1 and a second output lens 12L2 are arranged at positions optically facing the input lenses (11L1, 11L2) of the first input lens group (11L1, 11L1, ...) and the second input lens group (11L2, 11L2, ...).
The fly's eye lens 10 has a first input lens group (11L1, 11L1, ...) arranged at the upper and lower ends of the input lens assembly 11A in the vertical direction, and a second input lens group (11L2, 11L2, ...) arranged in the vertical center of the input lens assembly 11A.

The light-transmitting member is formed so that the second input lens 11L2 side is higher and a step is provided so that the heights of the first input lens 11L1 and the second input lens 11L2 at the input surface 10In are uniform. The light-transmitting member is formed so that the second output lens 12L2 side is higher and a step is provided so that the heights of the first output lens 12L1 and the second output lens 12L2 at the output surface 10Ex are uniform.
Each lens and flat region constituting the fly-eye lens 10 will be described below.

(Inlet lens)
1 and 2A to 2E, the input lens 11L is a lens formed on the input surface 10In of the fly-eye lens 10. Each input lens 11L receives light LB and supplies it to an optically opposed output lens 12L. Here, optically opposed means that the input lenses 11L are in a positional relationship in which light from one input lens 11L is input to one output lens 12L.
As an example, the input lens 11L is a first input lens 11L1 and a second input lens 11L2, which are two types of lenses with different sizes (lens dimensions). The input lenses 11L are all formed to have the same or approximately the same focal length. Here, the lens size is used to mean the same as the lens dimensions (horizontal lens width and vertical lens width).

The first input lens 11L1 receives light LB and supplies light as a secondary light source to the optically opposed first output lens 12L1. The first input lens 11L1 is formed of a convex lens having a convex portion on the side where the light LB is incident, a Fresnel lens, or the like. The first input lens 11L1 is a lens formed without decentering, in which the center line of the lens and the center of the radius of curvature are on the same straight line.
The first incident lens 11L1 is a lens for irradiating the maximum irradiation area E1 on the irradiation surface EA, and its shape corresponds to the shape of the irradiation area E1.
Here, the first input lens 11L1 is formed in a barrel shape. In addition, an input side flat area 11F is formed between the first input lenses 11L1 adjacent in the horizontal direction. As an example, the fly-eye lens 10 is formed by arranging the first input lenses 11L1 two-dimensionally on the upper side of the fly-eye lens 10 with the number of horizontal lenses being "6" and the number of vertical lenses being "3", and also arranging the first input lenses 11L1 two-dimensionally on the lower side with the number of horizontal lenses being "6" and the number of vertical lenses being "3". The shape of the first input lens 11L1 may be a barrel shape, a circle shape, an ellipse shape, a rounded rectangle shape, or the like, as long as it can secure the input side flat area 11F in a part of the periphery of the first input lens 11L1. In addition, the first input lens 11L1 may be a rectangular shape with the input side flat area 11F secured all around the periphery.

The second input lens 11L2 receives the light LB and supplies the light as a secondary light source to the optically opposed second output lens 12L2. The second input lens 11L2 is formed of a convex lens having a convex portion on the input side of the light LB, a Fresnel lens, or the like. The second input lens 11L2 is a lens formed without decentering, in which the center line of the lens and the center of the radius of curvature are on the same straight line.
The second incident lens 11L2 is a lens for irradiating an irradiation area E2, which is narrower than the irradiation area E1, on the irradiation surface EA, and its shape corresponds to the shape of the irradiation area E2.
Here, the second input lens 11L2 has a rectangular shape and does not have a flat area around it.
In addition, here, the second input lens 11L2 has a smaller lens size than the first input lens 11L1.
As an example, the fly-eye lens 10 is formed such that the number of second input lenses 11L2 in the vertical direction is the same as the number of first input lenses 11L1 in the vertical direction. Also, as an example, the fly-eye lens 10 is formed by two-dimensionally arranging the second input lenses 11L2 in the vertical center portion with the number of second input lenses 11L2 in the horizontal direction being "12" and the number of second input lenses 11L2 in the vertical direction being "6", so that the number of second input lenses 11L2 in the horizontal direction is twice the number of first input lenses 11L1.
The second input lens 11L2 is smaller than the first input lens 11L1 in order to irradiate an irradiation area E2 on the irradiation surface EA, which is narrower than the irradiation area E1. For example, the second input lens 11L2 is preferably formed to have lens dimensions that are 80% or less of the first input lens 11L1 in both the horizontal and vertical directions.

(Output lens)
As shown in FIG. 1 and FIG. 2A to FIG. 2E, the exit lens 12L is a lens formed on the exit surface 10Ex of the fly-eye lens 10. The exit lens 12L makes the entrance lens 11L and the irradiation surface EA conjugate (the image of the entrance lens 11L is formed on the irradiation surface EA). Specifically, each exit lens 12L is disposed at a position optically facing the entrance lens 11L and at a position near the focal point of the entrance lens 11L. The vicinity of the focal point of the entrance lens 11L includes the focal point of the entrance lens 11L and means the vicinity before and after it. In other words, the position of the exit lens 12L is not strictly limited to the focal distance position of the entrance lens 11L, and may be a position separated from the entrance lens 11L by a distance shorter than the focal length or longer than the focal length.
As an example, the output lenses 12L are a first output lens 12L1 and a second output lens 12L2, which are two types of lenses having different sizes (lens dimensions). Note that, here, the output lenses 12L are all formed to have the same or approximately the same focal length.

The first exit lens 12L1 forms an image of the light incident from the first entrance lens 11L1 on the irradiation surface EA. The first exit lens 12L1 is formed of a convex lens having a convex portion on the light exit side, a Fresnel lens, etc. The first exit lens 12L1 is a lens formed in a state without decentering, in which the center line of the lens and the center of the radius of curvature are on the same straight line.
The first exit lens 12L1 is a lens for irradiating the light supplied from the optically opposed first entrance lens 11L1 to the maximum irradiation area E1. The size of the first exit lens 12L1 is a size that includes at least the range in which the light LB, which is substantially parallel light, is condensed through the first entrance lens 11L1 on the exit surface 10Ex. This size depends on the angular characteristics of the light LB incident on the first entrance lens 11L1. The shape of the first exit lens 12L1 is not particularly limited, and although it is formed in a circular shape here, it may be an elliptical shape or the like.
The first exit lens 12L1 is formed of a substantially circular lens having a smaller area than the first entrance lens 11L1, and is formed so that upper and lower parts are partly adjacent lenses and connected in a line.

The second exit lens 12L2 forms an image of the light incident from the second entrance lens 11L2 on the irradiation surface EA. The second exit lens 12L2 is formed of a convex lens having a convex portion on the light exit side, a Fresnel lens, etc. Here, the second exit lens 12L2 is described as a lens formed in a state without decentering, in which the center line of the lens and the center of the radius of curvature are on the same straight line.
The second exit lens 12L2 is a lens for irradiating the light supplied from the optically opposed second entrance lens 11L2 to the irradiation area E2 via the condenser lens 50. The size of the second exit lens 12L2 is a size that includes at least the range in which the light LB, which is substantially parallel light, is condensed via the second entrance lens 11L2 on the exit surface 10Ex. Here, as an example, the second exit lens 12L2 is formed in a rectangular shape with the same size as the second entrance lens 11L2.

(Flat area on the entrance side)
As shown in FIG. 1 and FIG. 2A to FIG. 2E, the incident-side flat region 11F is a flat region formed on the incident surface 10In of the fly's eye lens 10 and having no curvature between the incident lenses 11L.
The incident-side flat region 11F receives the light LB, which is substantially parallel light, and supplies the light to the exit-side flat region 12F without changing the traveling direction of the light.
The incident-side flat region 11F is formed, for example, between the lenses of the first incident lens 11L1 spaced apart in the horizontal direction.
In addition, the incident side flat region 11F does not necessarily have to be formed between lenses spaced apart in the horizontal direction, as long as the light LB can pass through the flat region 11F without changing its direction of travel. For example, the flat region may be formed between lenses spaced apart in the vertical direction. Also, for example, the first incident lens 11L1 may be formed without being spaced apart in the horizontal and vertical directions, and flat regions may be formed at the four corners of the first incident lens 11L1.

(Flat area on the exit side)
As shown in FIG. 1 and FIG. 2A to FIG. 2E, the exit-side flat region 12F is a flat region formed on the exit surface 10Ex of the fly-eye lens 10 and having no curvature between the exit lenses 12L.
The exit-side flat region 12F irradiates the light supplied from the entrance-side flat region 11F via the condenser lens 50 onto an irradiation region E3.
The exit side flat region 12F is formed, for example, between the horizontally spaced lenses of the first exit lens 12L1. The exit side flat region 12F includes the exit range of the light LB, which is substantially parallel light supplied from the incident side flat region 11F, on the exit surface 10Ex, and is formed to be larger than the area of the exit range. That is, the size of the exit side flat region 12F is equal to or larger than the size of the incident side flat region 11F. This size depends on the angular characteristics of the light LB.

As a result, the fly's eye lens 10 emits the substantially parallel light LB incident on the first entrance lens 11L1 from the opposing first exit lens 12L1, and irradiates the light via the condenser lens 50 onto an irradiation area E1 on the irradiation surface EA.
In addition, the fly's eye lens 10 emits the approximately parallel light LB incident on the second input lens 11L2 from the opposing second output lens 12L2, and irradiates the light via the focusing lens 50 onto an irradiation area E2 on the irradiation surface EA that is narrower than the irradiation area E1.
In addition, the fly's eye lens 10 emits the approximately parallel light LB incident on the incident side flat region 11F from the opposing exit side flat region 12F, and irradiates the light via the focusing lens 50 onto an irradiation area E3 on the irradiation surface EA, which is even narrower than the irradiation area E2.
In this way, the fly's eye lens 10 irradiates light such that more light is superimposed toward the central region of the irradiation surface EA, thereby increasing the illuminance.

[Relationship between the optical path of the fly-eye lens and the illumination area]
Next, the relationship between the optical path of the fly's eye lens 10 and the irradiation area will be described with reference to FIGS. 3A to 3C.
(First entrance lens)
3A, it is assumed that light LB (LB1, LB2), which is substantially parallel light, is incident on the first incident lens 11L1 of the fly-eye lens 10. Here, light perpendicular to the incident surface 10In is indicated by a solid line (LB1), and light at an angle to the light LB1 is indicated by a dashed line (LB2).
The light LB1 incident on the first input lens 11L1 is focused by the first input lens 11L1 onto the first output lens 12L1 that is located a distance away from the first input lens 11L1 by the focal length of the first input lens 11L1.
The light emitted from the first output lens 12L1 is collected by the collecting lens 50 and irradiated onto a predetermined irradiation range. Here, the predetermined irradiation range is the size of the irradiation surface of the target to be irradiated.
As a result, the light from each of the multiple first input lenses 11L1 illuminates the same illumination area E1 on the illumination surface EA.

In addition, for light LB2 having an angle with respect to light LB1, the light incident on the same first entrance lens 11L1 is focused by the focusing lens 50 according to the angle via the same first exit lens 12L1, and irradiates the same irradiation area E1 as light LB1 on the irradiation surface EA.
In this way, the light LB incident on the first input lens 11L1 is irradiated on the irradiation surface EA so that the irradiation area E1 that is proportional to the size of the first input lens 11L1 becomes the irradiation range.

(Second entrance lens)
3B, it is assumed that light LB (LB1), which is a substantially parallel light, is incident on the second incident lens 11L2 of the fly-eye lens 10. Here, light perpendicular to the incident surface 10In is shown by a solid line (LB1), and parallel light having an angle with respect to the light LB1 is omitted from the illustration.
The light LB1 incident on the second input lens 11L2 is focused by the second input lens 11L2 onto the second output lens 12L2 that is located a distance away from the second input lens 11L2 by the focal length of the second input lens 11L2.
The light emitted from the second emission lens 12L2 is condensed by the condenser lens 50 and irradiated onto a predetermined irradiation range.
As a result, the light from each of the multiple second input lenses 11L2 irradiates the same irradiation area E2 on the irradiation surface EA.

Incidentally, light (not shown) having an angle with respect to the light LB1 also irradiates the irradiation area E2 in the same manner as described with reference to FIG. 3A.
In this way, the light LB incident on the second input lens 11L2 is irradiated on the irradiation surface EA so that the irradiation range is an irradiation area E2 that is proportional to the size of the second input lens 11L2 and is narrower than the irradiation area E1 (Figure 3A).

(Flat area on the entrance side)
3C, it is assumed that light LB (LB1, LB2), which is substantially parallel light, is incident on the incident-side flat region 11F of the fly-eye lens 10. Here, light perpendicular to the incident surface 10In is indicated by a solid line (LB1), and light at an angle to the light LB1 is indicated by a dashed line (LB2).
The light LB1 incident on the incident-side flat region 11F passes through the fly-eye lens 10 and illuminates the condenser lens 50.
The light irradiated to the condenser lens 50 is condensed by the condenser lens 50 and irradiated onto the irradiation surface EA. At this time, the light LB1 irradiates one point on the irradiation surface EA.
Similarly to the light LB1, the light LB2, which is angled with respect to the light LB1, passes through the fly-eye lens 10 and is irradiated onto the irradiation surface EA. At this time, the light LB2 irradiates a point on the irradiation surface EA that is different from the point on the irradiation surface EA where the light LB1 is irradiated.
In this way, the light LB, which is approximately parallel light incident on the incident side flat region 11F, has an angle with respect to the light perpendicular to the incident surface 10In, so that the irradiation range on the irradiation surface EA is not a single point but an irradiation area E3 having an area.

[Relationship between the optical path of light incident on the flat area and the entrance lens and exit lens]
Next, the optical path of the light incident on the fly-eye lens 10 and the relationship between the flat region, the entrance lens, and the exit lens will be described with reference to FIGS. 4A and 4B.
4A, if the light LB that is substantially parallel and incident on the incident surface 10In is perpendicular to the incident surface 10In, the light that is incident on the first incident lens 11L1 is focused at the position of the first output lens 12L1. Therefore, it is preferable that the size of the first output lens 12L1 is smaller than that of the first input lens 11L1.
Moreover, the incident side flat region 11F and the exit side flat region 12F may be of the same size.
However, as shown in FIG. 4B, the light LB incident on the incident surface 10In actually has an angle.
Therefore, the light incident on the first input lens 11L1 is focused on the output surface 10Ex within a range according to the angular characteristics. Therefore, it is preferable that the size of the first output lens 12L1 is larger than the focusing range in which the light LB reaches the output surface 10Ex via the first input lens 11L1.
Furthermore, it is preferable that the exit side flat region 12F between the first exit lenses 12L1 is larger than the range that reaches the exit surface 10Ex, depending on the angular characteristics of the light LB that passes through the entrance side flat region 11F between the first entrance lenses 11L1.
This allows the light incident on the first input lens 11L1 of the fly-eye lens 10 to be accurately irradiated onto the irradiation area E1 on the irradiation surface EA (FIG. 1).

(Modification of Fly-Eye Lens)
The fly-eye lens 10 described above is not limited to the above-mentioned configurations.
Here, the second input lens 11L2 is rectangular and does not have a flat area around the periphery. However, the second input lens 11L2 may have a shape that allows a flat area (entrance side flat area) to be formed in part or all of the periphery. For example, the second input lens 11L2 may have a barrel shape, an ellipse shape, a rounded rectangle shape, or the like.
In this case, the second output lens 12L2 is made smaller than the second input lens 11L2, and a flat region is formed between the lenses. The size of the flat region between the second output lenses 12L2 depends on the angular characteristics of the light LB, and is formed to include the emission range of the light LB, which is a substantially parallel light beam, supplied from the flat region formed between the lenses of the second input lens 11L2, and to be larger than the area of the emission range.

In this embodiment, the second output lens 12L2 is not decentered.
However, it is preferable that the output lens group 12A overlaps the irradiation range at the center of the irradiation area and forms the position of the lens apex of the output lens 12L so as to shift the position of the irradiation range. This makes it possible to suppress a sudden change in illuminance in the irradiation area. Note that the output lens group 12A may form the position of the lens apex of the output lens group (12L2, 12L2, ...) other than the output lens group (12L1, 12L1, ...) optically opposed to the input lens group (11L1, 11L1, ...) having the largest lens size, so as to overlap the irradiation range at the center of the irradiation area and to shift the position of the irradiation range.

For example, the positions of the apexes of some or all of the second exit lenses 12L2 are decentered, and the lens center and the center of the radius of curvature are formed with an amount of decentering that is offset from the same line. In this case, the second exit lenses 12L2 are formed in advance so that the irradiation area is dispersed in the horizontal and vertical directions by several percent to several tens of percent of the irradiation area E2 in the case of no decentering on the irradiation surface EA irradiated through the condenser lens 50. The amount of decentering of all the second exit lenses 12L2 may be changed according to their positions, and the amount of decentering may be changed on a column-by-column and row-by-row basis according to the positions shifted in the horizontal and vertical directions from the center of the lens group of the entire second exit lenses 12L2. Of course, the amount of decentering of all the second exit lenses 12L2 may be different.
This causes the illumination area E2 by each second output lens 12L2 to shift in accordance with the amount of eccentricity, and as shown in FIG. 5, a sudden change in illuminance at the boundary between the illumination area E1 and the illumination area E2 can be suppressed.

Moreover, here, the fly-eye lens 10 is integrally configured using a light-transmitting member.
However, the fly-eye lens 10 may be separated into an input lens member 10sp1 and an output lens member 10sp2, each having a light input surface 10In and an output surface 10Ex, as shown in FIG. 6, and the fly-eye lens 10 may be configured as a hollow fly-eye lens 10A.

At this time, the fly-eye lens 10A can be achieved by separating the input lens member 10sp1 and the output lens member 10sp2 so that the position of the output lens 12L is near the focal point of the input lens 11L. For example, the input lens member 10sp1 and the output lens member 10sp2 can be fixed by a frame, spaced apart by approximately the focal length of the input lens 11L.

Further, here, the entrance lens assembly 11A and the exit lens assembly 12A are each configured with two types of lens groups of different sizes, which are arranged over the entire light entrance surface 10In and the light exit surface 10Ex.
In the fly-eye lens 10, the entrance lens assembly 11A and the exit lens assembly 12A may each be configured with a lens group of one size. In addition, the fly-eye lens 10 may form an entrance-side flat region formed of a flat light-transmitting member in which the entrance lenses 11L are not arranged in the entrance lens assembly 11A, and form an entrance-side flat region formed of a flat light-transmitting member in which the exit lenses 12L are not arranged in the exit lens assembly 12A. In other words, the lens region and the flat region may be separated, and the lens assembly may be formed by adjacently separating the regions.

For example, it may be configured as a fly-eye lens 10B shown in Fig. 7A. The fly-eye lens 10B includes an input lens assembly 11A having a plurality of input lenses (second input lenses 11L2, 11L2, ...) two-dimensionally arranged on the light input surface 10In and an input-side flat region 11F formed of a flat light-transmitting member in which the input lenses are not arranged, and an output lens assembly 12A having a plurality of output lenses (second output lenses 12L2, 12L2, ...) two-dimensionally arranged on the light output surface 10Ex and an output-side flat region 12F formed of a flat light-transmitting member in which the output lenses are not arranged. The output lens (second output lens 12L2) is formed at a position optically facing the input lens (second input lens 11L2), and the output-side flat region 12F is formed in a region optically facing the input-side flat region 11F.
Here, the fly-eye lens 10B has an entrance lens (second entrance lens 11L2) constituting the entrance lens assembly 11A arranged separately on the upper and lower end sides on the entrance surface 10In, and has an entrance-side flat region 11F in the central portion. Also, the fly-eye lens 10B has an exit lens (second exit lens 12L2) constituting the exit lens assembly 12A arranged separately on the upper and lower end sides on the exit surface 10Ex, optically facing the entrance lens (second entrance lens 11L2) and the entrance-side flat region 11F, and has an exit-side flat region 12F in the central portion.

In this case, as shown in Figure 7B, the fly's eye lens 10B can irradiate light emitted from the output lens (second output lens 12L2) of the output lens assembly 12A onto an irradiation area E2 on the irradiation surface EA, and can further superimpose and irradiate light emitted from the output-side flat area 12F onto an irradiation area E3.
In addition, the output lens assembly 12A of the fly-eye lens 10B may overlap the irradiation range at the center of the irradiation area, and the position of the lens apex of the output lens 12L may be formed so as to shift the position of the irradiation area. This makes it possible to disperse the irradiation area E2 and suppress a sudden change in illuminance in the irradiation area, as shown in Figure 7C.

8A and 8B, the fly-eye lens 10C may be configured as the fly-eye lens 10C or 10D. The fly-eye lens 10C is formed by replacing the second input lens 11L2 and the second output lens 12L2 of the fly-eye lens 10B with a first input lens 11L1 and a first output lens 12L1, respectively, having flat regions formed of a flat light-transmitting member between at least some or all of the lenses (here, between the lenses in the horizontal direction).
The fly-eye lens 10D is formed by two-dimensionally arranging first entrance lenses 11L1, 11L1, . . . over the entire entrance surface 10In, and by two-dimensionally arranging first exit lenses 12L1 over the entire exit surface 10Ex.
In this case, as shown in Figure 8C, the fly-eye lenses 10C and 10D can irradiate light emitted from the first output lens 12L1 of the output lens assembly 12A onto an irradiation area E1 on the irradiation surface EA, and can further superimpose and irradiate light emitted from the output-side flat area 12F onto an irradiation area E3.

Furthermore, in the fly-eye lens 10, the entrance lens assembly 11A and the exit lens assembly 12A may be configured with three or more types of lens groups each formed with three or more types of lenses of different sizes. Even in this case, it is necessary to form a flat area in part or all of the periphery of the lens in at least one of the opposing lens groups, or to form a flat area in which no lenses are arranged in part.
This allows the formation of an illumination distribution on the illumination surface EA, in which the illumination range varies depending on the size of the lens, and the illumination distribution is brighter toward the center.
In this case, it is preferable that the lens groups other than the lens group of the output lens group 12A that is optically opposed to the lens group with the largest lens dimension in the input lens group 11A be formed with an eccentricity amount such that the lens center and the center of the radius of curvature are shifted from the same straight line, as in the second output lens 12L2 described above.
This makes it possible to suppress abrupt changes in illuminance at the boundaries of the illumination areas of the lens groups.
Further, although an example has been described here in which the flat region is formed in the center of the lens assembly, it is sufficient if the lens region and the flat region are formed separately in the lens assembly, such as by arranging the lens region and the flat region alternately.

In the fly-eye lenses 10A to 10D, the lens shape and the like may be changed as described for the fly-eye lens 10.
Furthermore, like the fly-eye lens 10A, the fly-eye lenses 10B to 10D may be configured to be separated into an entrance lens member and an exit lens member each having a light entrance surface 10In and an exit surface 10Ex.
The fly-eye lenses 10A to 10D also have the same functions and effects as those described for the fly-eye lens 10.

[Configuration of the Illumination Optical Device]
Next, an illumination optical device 100 will be described with reference to Fig. 9. Note that, here, a configuration using the fly-eye lens 10 will be described as an example. Of course, the fly-eye lens 10 may be configured with the fly-eye lenses described in the modified examples, such as the fly-eye lenses 10A (Fig. 6), 10B (Fig. 7A), 10C (Fig. 8A), and 10D (Fig. 8B).

The illumination optical device 100 is used as various lighting fixtures for vehicles, ships, aircraft, etc. The illumination optical device 100 includes a light source 20, an optical member 30, a fly-eye lens 10, an optical modulation device 70, and a projection lens 80. The light source 20 to the projection lens 80 are housed in a frame (not shown).

The light source 20 is configured to emit, for example, white light. For example, a light emitting device in which a light emitting element is housed in a package and a light-transmitting member is provided is used as the light source 20. The light emitting element used here can be a known one, and for example, a light emitting diode or a laser diode is preferably used. In addition, the light emitting element can be selected from one with any wavelength. For example, a nitride semiconductor ((In _x Al _y Ga _1-X-Y N), (0≦X, 0≦Y, X+Y≦1)) or GaP can be used as a blue or green light emitting element. Furthermore, GaAlAs, AlInGaP, etc. can be used as a red light emitting element. Note that the light emitting element can also be a semiconductor light emitting element made of a material other than those described above. The composition, emission color, size, number, etc. of the light emitting element can be appropriately selected according to the purpose.

The optical member 30 converts the light from the light source 20 into approximately parallel light. As an example of the optical member 30, a collimating lens is used, and here, the light from the light source 20 is converted into approximately parallel light by a first collimating lens 31 and a second collimating lens 32. The collimating lens used here may be a combination of concave and convex lenses, a combination of convex lenses, or may be composed of a compound lens or a single lens, as long as it is configured to convert the light from the light source 20 into approximately parallel light.

The fly-eye lens 10 receives light from the optical member 30 and distributes the desired light irradiation intensity, and has the configuration already described. The fly-eye lens 10 is positioned so that the desired light irradiation intensity distribution is irradiated onto the irradiation surface of the light modulation device 70. Note that the fly-eye lens 10 is not limited in the number of lenses, the number of different sizes of lenses, etc., as long as the desired light irradiation intensity distribution can be obtained.

The light modulation device 70 changes the light path of the light incident from the fly-eye lens 10 as a desired distribution of light irradiation intensity, and outputs the light with variable light distribution. This light modulation device 70 is, for example, a DMD (digital micromirror device). The light modulation device 70 can adjust the light incident on the fly-eye lens 10 to a portion where light is desired to be emitted and a portion where light is not desired to be emitted. Since the incident light already forms a desired distribution of light irradiation intensity, the light modulation device 70 can reflect the light and emit it to the projection lens 80 without any loss of light flux. In other words, the light modulation device 70 can realize a distribution characteristic of light irradiation intensity in which the center part is brighter than the entire irradiation area as a luminous intensity distribution required for a headlight, for example, without any loss of light flux. Note that the light modulation device 70 is formed, as an example, so that the light reflected by the reflecting mirror 71 is reflected and sent to the projection lens 80.

The projection lens 80 magnifies and emits the light irradiated from the light modulation device 70. The projection lens 80 may be composed of a single lens or a compound lens. The projection lens 80 irradiates the light having a desired light irradiation intensity distribution state sent by the light modulation device 70 onto an image forming plane at a preset distance.
In the illumination optical device 100 having the above-described configuration, the light from the light source 20 is adjusted via the fly-eye lens 10 to a desired distribution of light irradiation intensity, and is emitted by the optical modulator 70 without any light flux loss, and the light is irradiated to the outside via the projection lens 80.

(Modification of Illumination Optical Apparatus)
In the illumination optical device 100, the optical member 30 may be configured as shown in FIGS. 10A and 10B.
10A, the optical member 30A may be configured to include a parabolic reflector 33. The parabolic reflector 33 is disposed so as to reflect the light emitted from the light source 20 and cause the light to enter the fly's eye lens 10 as substantially parallel light. When the parabolic reflector 33 is used, the light source 20 is disposed so as to emit light from the light source 20 toward the parabolic reflector 33. The light source 20 is disposed at a position near the focal point of the parabolic reflector 33.
10B, the optical member 30B may be configured to include an elliptical reflecting mirror 34. The elliptical reflecting mirror 34 uses the upper half of the elliptical curved surface to reflect the light from the light source 20 as substantially parallel light. The light source 20 is installed at an angle and position such that the light irradiated toward the elliptical reflecting mirror 34 becomes substantially parallel light.
Furthermore, in the illumination optical apparatus 100, the DMD has been described as an example of the light modulation device 70, but other devices such as a spatial light modulator may also be used.

The fly-eye lens and illumination optical device according to the present invention can be used as an optical system or illumination device for various lighting light sources in vehicles such as motorcycles and automobiles, or in vehicles such as ships and aircraft. They can also be used in optical systems or illumination devices for various light sources, such as spotlights and other illumination light sources, display light sources, in-vehicle parts, indoor lighting, outdoor lighting, etc.

10, 10A, 10B, 10C, 10D Fly's eye lens 10In Incident surface 10Ex Exit surface 10sp1 Incident lens member 10sp2 Exit lens member 11A Incident lens assembly 11L Incident lens 11L1 First incident lens 11L2 Second incident lens 11F Incident side flat region 12A Exit lens assembly 12L Exit lens 12L1 First exit lens 12L2 Second exit lens 12F Exit side flat region 20 Light source 30, 30A, 30B Optical member 31 Collimating lens 32 Collimating lens 33 Parabolic reflecting mirror 34 Elliptical reflecting mirror 70 Light modulation device 71 Reflecting mirror 80 Projection lens 100 Illumination optical device

Claims (13)

an incidence lens assembly in which incidence lenses are two-dimensionally arranged on a light incidence surface;
an output lens assembly in which output lenses are arranged optically opposite the input lenses and are two-dimensionally arranged on a light output surface,
the input lens assembly includes a first input lens group and a second input lens group each including a plurality of first input lenses and a plurality of second input lenses having a lens size smaller than that of the first input lenses;
The first input lens group is disposed on the upper and lower ends of the input lens assembly in the vertical direction, with input side flat regions being formed between the lenses by a flat light-transmitting member,
the second input lens group is disposed in a vertical center portion of the input lens assembly, with the input-side flat area not being formed between the lenses;
the emission lens assembly has an emission-side flat region formed of a flat light-transmitting member optically facing the incidence-side flat region,
The exit lens assembly is a fly's eye lens in which multiple exit lens groups corresponding to each of the entrance lens groups of the entrance lens assembly are arranged with different lens dimensions for each exit lens group, and the illumination range of each light emitted from the exit lenses of the exit lens groups with different lens dimensions differs from that of the light emitted from the exit side flat region. The fly-eye lens of claim 1, in which the light-transmitting member is formed between the entrance surface and the exit surface, and the entrance lens assembly and the exit lens assembly are integrally formed. A fly-eye lens according to claim 1 or 2, in which the exit lens is formed at a position near the focal point of the optically opposing entrance lens. The fly's eye lens according to any one of claims 1 to 3, wherein the shape of the entrance lens having the entrance side flat area on its periphery is a circle, a barrel, an ellipse, or a rounded rectangle. The fly-eye lens according to any one of claims 1 to 4, wherein the exit lens is a lens whose size includes the range of light that reaches the exit surface via the entrance lens that is optically opposed to the exit lens. The fly-eye lens according to any one of claims 1 to 5, wherein the output lens assembly overlaps the illumination range at the center of the illumination region, and the lens apex of the output lens is positioned so as to shift the position of the illumination range. A fly-eye lens according to any one of claims 1 to 5, in which the illumination ranges of the output lens group other than the output lens group optically opposed to the input lens group having the largest lens dimensions are overlapped in the center of the illumination region, and the positions of the lens vertices are formed so as to shift the positions of the illumination ranges. 8. The fly's eye lens according to claim 1, wherein the second input lens is formed to have lens dimensions each of which in a horizontal direction and a vertical direction is 80% or less of that of the first input lens. 9. The fly's eye lens according to claim 1 , wherein a size of the exit-side flat region is equal to or larger than a size of the entrance-side flat region. 10. An illumination optical device comprising: an optical element disposed in an optical path from a light source and converting light from the light source into approximately parallel light; the fly-eye lens according to claim 1 which receives light from the optical element and outputs it as light having a desired light irradiation intensity distribution; an optical modulation device which receives the light from the fly-eye lens, changes the optical path, and outputs the light; and a projection lens which projects the light from the optical modulation device. The illumination optical device according to claim 10 , wherein the light source is a light emitting diode or a laser diode. 12. The illumination optical device according to claim 10 , wherein the optical member is a collimating lens that converts the light from the light source into substantially parallel light. 12. The illumination optical device according to claim 10 , wherein the optical member is a reflecting mirror that reflects the light from the light source to form substantially parallel light.