Optical lens, light source device, and lighting apparatus

Abstract

An optical lens (2) has a transmission part (22) formed at a position facing a light source (1) in the optical axis direction, and total reflection parts (23) formed on side portions of the optical lens (2). The central axis of the transmission part (22) is not disposed on the optical axis of the light source (1). The central axis of the total reflection parts (23) is not disposed on the optical axis of the light source (1) and is inclined with respect to the optical axis of the light source (1).

Description

Optical lens, light source device and lighting device

[0001] The present disclosure relates to an optical lens, a light source device, and an illumination device.

[0002] 2. Description of the Related Art Conventionally, there have been lighting devices that have a cutoff function for cutting off light emitted in a predetermined direction.

[0003] The lighting device of Patent Document 1 includes a light-emitting element, a first lens that receives light emitted from the light-emitting element and outputs a first output light, and a second lens that receives the first output light and outputs a second output light. The first lens has a first output surface that outputs the first output light and is formed in a convex shape that protrudes in the optical axis direction of the light-emitting element. This makes it difficult for the first output light to be incident on a lens-processed portion formed below the second output surface of the second lens, thereby suppressing the generation of stray light.

[0004] Patent No. 7349634

[0005] However, increasing the number of lenses included in a lighting device increases the number of steps required to process the lighting device.Furthermore, when light emitted from a light-emitting element enters a lens, Fresnel reflection occurs, so increasing the number of lenses included in a lighting device reduces the luminous efficiency of the lighting device.

[0006] Therefore, an object of the present disclosure is to provide an optical lens, a light source device, and an illumination device that can reduce the number of lenses used in the illumination device.

[0007] In order to achieve the above object, an optical lens according to one embodiment of the present disclosure has a transmissive portion formed at a position opposite to a light source in the optical axis direction, and a total reflective portion formed on a side of the optical lens, wherein the central axis of the transmissive portion is not positioned on the optical axis of the light source, and the central axis of the total reflective portion is not positioned on the optical axis of the light source and is inclined with respect to the optical axis.

[0008] According to the present disclosure, the number of lenses used in the lighting device can be reduced.

[0009] FIG. 1 is a diagram showing an illumination device according to the first embodiment. FIG. 2 is a diagram for explaining the function of a total reflection section according to the first embodiment. FIG. 3 is a diagram for explaining the function of a total reflection section according to the first embodiment. A side view for explaining the function of a transmission section according to the first embodiment. A side view showing an example of the arrangement of an illumination device according to the first embodiment. A side view of an illumination device according to the second embodiment. A side view of an illumination device according to the third embodiment. A diagram showing an illumination device according to the fourth embodiment. A diagram showing an illumination device according to the fifth embodiment. A diagram showing an illumination device according to a modification of the fifth embodiment. A diagram showing an illumination device according to the sixth embodiment. A diagram showing an illumination device according to the seventh embodiment. A side view of an illumination device according to the eighth embodiment. A diagram showing an illumination device according to the ninth embodiment. A side view of an illumination device according to a modification of the ninth embodiment. A diagram showing a lens array used in an illumination device according to the tenth embodiment. A front view of a lens array used in an illumination device according to a modification of the tenth embodiment. A diagram showing a lens array used in an illumination device according to the eleventh embodiment. A diagram showing a lens array used in an illumination device according to the twelfth embodiment.

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiment is essentially merely illustrative and is not intended to limit the present invention, its applications, or its uses. In the following description, the same parts will be designated by the same reference numerals, and detailed description will be omitted as appropriate.

[0011] (First embodiment) Fig. 1(a) is a side view of an illumination device according to a first embodiment, and Fig. 1(b) is a plan view of the illumination device according to the first embodiment. As shown in Figs. 1 and 2, an illumination device 100 includes a light source 1, an optical lens 2, and a housing 3. In the following description, the optical axis direction of the light source 1 is defined as the Z direction, the depth direction of Fig. 1(a) is defined as the X direction (second direction, corresponding to the horizontal direction), and the up-down direction of Fig. 1(a) is defined as the Y direction (first direction). In Fig. 1 and other figures, light emitted from the light source 1 is indicated by solid or dashed arrows. The light source 1 and the optical lens 2 correspond to a light source device and an illumination device.

[0012] 1, the light source 1 is formed of an LED or the like, and has an optical axis T1 in the Z direction. In this embodiment, the optical axis T1 of the light source 1 is the central axis of the radiation distribution of the light source 1.

[0013] The optical lens 2 is a lens made of a light-transmitting material such as glass, resin, etc. The optical lens 2 receives light from the light source 1 and emits emitted light.

[0014] The optical lens 2 includes an entrance 21 , a transmission portion 22 , a total reflection portion 23 , and an exit surface 24 .

[0015] The light entrance 21 is disposed on the side of the optical lens 2 facing the light source 1 (the left side in FIG. 1A ). The light entrance 21 is formed in a concave shape so as to surround the light source 1. The light entrance 21 receives light emitted from the light source 1.

[0016] The transmitting portion 22 is formed on the bottom surface of the light entrance 21, at a position facing the optical axis direction of the light source 1. The transmitting portion 22 is formed in a spherical or rotationally symmetric shape. Light L1 incident on the transmitting portion 22 from the light source 1 passes through the transmitting portion 22 and is incident on the exit surface 24. The light source 1 is disposed so that the center of the light-emitting surface is located at the focal position of the transmitting portion 22. The central axis T3 of the transmitting portion 22 is the central axis of the radiation distribution of the emitted light that passes through the transmitting portion 22 and is emitted.

[0017] The total reflection portion 23 is formed on a side portion of the optical lens 2 between the incident port 21 and the exit surface 24. Specifically, the total reflection portion 23 is formed so as to connect the outer circumferential end of the incident port 21 and the outer circumferential end of the exit surface 24. The total reflection portion 23 is formed in a shape that is rotationally symmetric about the central axis T2. In this embodiment, the total reflection portion 23 is formed in a parabolic shape having a focal point on the central axis T2. Light L2 transmitted from the light source 1 through the side portion of the incident port 21 is totally reflected by the total reflection portion 23 and enters the outer circumferential portion of the exit surface 24. In FIG. 1A , the central axis T2′ of the total reflection portion 23 is obtained by aligning the central axis T2 of the total reflection portion 23 in the Z direction (the optical axis direction of the light source 1) with the focal point of the total reflection portion 23 as the reference.

[0018] The exit surface 24 is disposed on the opposite side of the optical lens 2 from the entrance 21 (on the right side in FIG. 1A ). The exit surface 24 irradiates the light incident from the transmission portion 22 and the total reflection portion 23 to the outside of the lighting device 100 as irradiation light.

[0019] In this embodiment, if the distance between the central axis T2' of the total reflection section 23 and the optical axis T1 of the light source 1 is A1, the angle between the optical axis T1 of the light source 1 and the central axis T2 of the total reflection section 23 is B1, the angle between the optical axis T1 of the light source 1 and the central axis T3 of the transmission section 22 is B2, and the size of the light-emitting surface of the light source 1 is d, then 0.1×d≦A1≦3×d, 0.5°≦B1≦7°, and 0.1°≦B2≦20°.

[0020] Furthermore, if the focal length of the transmitting portion 22 is F, the distance from the center of the transmitting portion 22 to the optical axis T1 of the light source 1 is C, the size of the lens diameter (exit surface 24) of the optical lens 2 is D, the lens diameter of the transmitting portion 22 (the size of the transmitting portion 22) is D1, the opening diameter of the incident port 21 (the size of the opening of the transmitting portion 22) is D', and the angle between the side of the incident port 21 and the transmitting portion 22 is θ, then -0.3×F≦C≦0.3×F, 5×d≦D≦200×d, and D1≦D'.

[0021] (Function of Total Reflection Section 23) FIG. 2 is a diagram for explaining the function of the total reflection section according to the first embodiment. Specifically, FIG. 2(a) is a side view showing the positional relationship between the light source 1 and the total reflection section 23 in the first embodiment, FIG. 2(b) is a side view showing the positional relationship between the light source 1 and the total reflection section 23' in a comparative example, FIG. 2(c) is a diagram showing the irradiated light in the first embodiment, and FIG. 2(d) is a diagram showing the irradiated light in the comparative example. Note that in FIGS. 2(a) and 2(b), the lenses 2 and 2' are formed in the same shape, and are illustrated in an appropriately simplified manner to explain the function of the total reflection section. Also, FIGS. 2(c) and 2(d) are diagrams showing the irradiated light when the irradiated light is irradiated onto a wall surface or the like.

[0022] 2(b), in the optical lens 2' of the comparative example, the central axis T2' of the total reflection portion 23' is located at the same position as the optical axis T1 of the light source 1. In contrast, as shown in FIG. 2(a), in the optical lens 2 according to this embodiment, the optical axis T1 of the light source 1 is located below the central axis T2' of the total reflection portion 23 in the drawing (decentered).

[0023] 2(a) and 2(b), the irradiation surface of the light source 1 has a certain width in the Y direction. Therefore, the light emitted from the light source 1 and reflected by the total reflection portion 23 (23') has a wider width as it is reflected at a position closer to the light source 1, and the light reflected by the total reflection portion 23 (23') has a narrower width as it is reflected at a position farther from the light source 1.

[0024] As shown in FIG. 2B, in the optical lens 2′ of the comparative example, the light beam L21′ is reflected at a position P1 on the total reflection portion 23′ that is closer to the light source 1, resulting in a wider beam width. The light beam L22′ is reflected at a position P2 on the total reflection portion 23′ that is farther from the light source 1, resulting in a narrower beam width. As described above, in the optical lens 2′ of the comparative example, the central axis T2′ of the total reflection portion 23′ and the optical axis T1 of the light source 1 are aligned. Therefore, the directions of the light beam L21a′ at the top of the drawing of the light beam L21′ and the light beam L22a′ at the top of the drawing of the light beam L22′ do not coincide, making it impossible to sharply reduce the illuminance at the edge of the irradiated light. Therefore, in the optical lens 2′ of the comparative example, it is impossible to sharply reduce the illuminance at the edge of the irradiated light at the cut line C1′ (see FIG. 2D).

[0025] 2A, in optical lens 2 according to this embodiment, optical axis T1 of light source 1 is disposed (decentered) below central axis T2' of total reflection portion 23. As a result, the direction of light L21a at the upper end of light L21 reflected at position P1 in total reflection portion 23 close to light source 1 is the same as the direction of light L22a at the upper end of light L22 reflected at position P2 in total reflection portion 23 far from light source 1. As a result, in optical lens 2 according to this embodiment, the illuminance of the end of the irradiated light can be sharply reduced at cut line C1 (see FIG. 2C).

[0026] FIG. 3 is a diagram illustrating the function of the total reflection unit according to the first embodiment. Specifically, FIG. 3(a) is a side view showing the positional relationship between the light source 1 and the total reflection unit 23 in the first embodiment, FIG. 3(b) is a side view showing the positional relationship between the light source 1 and the total reflection unit 23' in a comparative example, FIG. 3(c) is a diagram showing the irradiated light in the first embodiment, and FIG. 3(d) is a diagram showing the irradiated light in the comparative example. Note that in FIGS. 3(a) and 3(b), the lenses 2 and 2' are formed in substantially the same shape, and the light source 1 is disposed at the focal point of the total reflection units 23 and 23', but the shapes of the total reflection units 23 and 23' are different. Also, FIGS. 3(c) and 3(d) are diagrams showing the irradiated light when irradiating a wall surface or the like.

[0027] As shown in Fig. 3(b), in the optical lens 2' of the comparative example, the central axis T2 of the total reflection portion 23' is located at the same position as the optical axis T1 of the light source 1. In contrast, as shown in Fig. 3(a), in the optical lens 2 according to this embodiment, the central axis T2 of the total reflection portion 23 is inclined (tilted) with respect to the optical axis T1 of the light source 1.

[0028] As shown in FIG. 3B, in the comparative example, light L2' emitted from light source 1 is converted into parallel light by the transmission portion 22 and total reflection portion 23' of optical lens 2 and is irradiated to the right side of the drawing. Here, light L3', which is a portion of light L2' incident from light source 1 onto side portion 21a of entrance 21, does not pass through side portion 21a of entrance 21 and is reflected by Fresnel reflection. Light L3' is reflected by side portion 21a of entrance 21 to the upper right side of the drawing, and becomes stray light. Therefore, in optical lens 2' of the comparative example, the illuminance of the end of the irradiated light cannot be sharply reduced at cut line C2' (see FIG. 3D).

[0029] 3A, in contrast, the central axis T2 of total reflection portion 23 extends toward the upper right side of the drawing. As a result, light L2 reflected by side portion 21a of entrance 21 from light source 1 and light L3 are irradiated in the same direction along central axis T2 of total reflection portion 23. Therefore, in optical lens 2 according to this embodiment, the illuminance of the end portion of the irradiated light can be made to drop sharply at cut line C2 (see FIG. 3C).

[0030] (Function of the Transmitting Section 22) FIG. 4 is a diagram for explaining the function of the transmitting section according to the first embodiment. Specifically, FIG. 4( a) is a side view showing the positional relationship between the light source 1 and the transmitting section 22 in the first embodiment, FIG. 4( b) is a side view showing the positional relationship between the light source 1 and the transmitting section 22′ in a comparative example, FIG. 4( c) is a diagram showing the irradiated light in the first embodiment, and FIG. 4( d) is a diagram showing the irradiated light in the comparative example. Note that in FIGS. 4( a) and 4(b), the lenses 2 and 2′ are formed in substantially the same shape, but the shapes of the transmitting sections 22 and 22′ are different, and both the transmitting sections 22 and 22′ are formed in a spherical shape. Also, FIGS. 4(c) and 4(d) are diagrams showing the irradiated light when irradiating the irradiated light onto a wall surface or the like.

[0031] As shown in Fig. 4(b), in the optical lens 2' of the comparative example, the central axis T3 of the transmissive portion 22' is located at the same position as the optical axis T1 of the light source 1. In contrast, as shown in Fig. 4(a), in the optical lens 2 according to this embodiment, the central axis T3 of the transmissive portion 22 is inclined (tilted) with respect to the optical axis T1 of the light source 1.

[0032] As described above, in the lighting device according to this embodiment, the central axis T2 of the total reflection portion 23 is inclined with respect to the optical axis T1 of the light source 1. Therefore, as shown in Figures 4(a) and 4(b), the light L2 emitted from the light source 1 is converted into parallel light by the transmission portion 22 and the total reflection portion 23 and is irradiated toward the upper right side of the drawing.

[0033] 4(b), when the central axis T3 of the transmissive portion 22' and the optical axis T1 of the light source 1 are aligned, the light L1' transmitted through the transmissive portion 22' is irradiated to the right side of the drawing. As a result, the directions of the light L2 and the light L1' do not match, and the illuminance at the edge of the irradiated light cannot be reduced sharply. Therefore, in the optical lens 2' of the comparative example, the illuminance at the edge of the irradiated light cannot be reduced sharply at the cut line C3' (see FIG. 4(d)).

[0034] 4(a), in contrast, the central axis T3 of the transmissive portion 22 extends to the upper right of the drawing. As a result, light L1 and light L3 transmitted through the transmissive portion 22 are irradiated in the same direction along the central axis T3 of the transmissive portion 22'. Therefore, in the optical lens 2 according to this embodiment, the illuminance of the end of the irradiated light can be sharply reduced at the cut line C3 (see FIG. 4(c)).

[0035] As described above, in total reflection unit 23, the optical axis T1 of light source 1 and the central axis T2' of total reflection unit 23 are disposed (decentered) so that light L21a at the top of the drawing, of light L21 (first light) reflected at point P1 (first point) that is close in focal distance from light source 1, and light L22a at the bottom of the drawing, of light L22 (second light) reflected at point P2 (second point) that is far in focal distance from light source 1, substantially coincide with the cut line. The central axis T2 of total reflection unit 23 is inclined (tilted) with respect to the optical axis T1 of light source 1 so that light L3 (third light) reflected at side portion 21a of entrance 21 and light L2 (fourth light) reflected by total reflection unit 23 are irradiated in substantially the same direction. The central axis T3 of the transmissive portion 22 is inclined (tilted) with respect to the optical axis T1 of the light source 1 so that the light L1 (fifth light) transmitted through the transmissive portion 22 and the light L2 (fourth light) reflected by the total reflection portion 23 are irradiated in directions that are approximately aligned. This allows the light beams L21a and L22a to be irradiated along the cutoff line, and the irradiation directions of the light beams L1 to L3 are aligned, allowing the illuminance of the end of the irradiated light to drop sharply at the cutoff line. Furthermore, this configuration allows an illumination device with a cutoff function to be configured using a single optical lens, thereby reducing the number of lenses used in the illumination device.

[0036] Since the light L3 reflected at the side 21a of the entrance 21 is basically stray light, the central axis T2 of the total reflection section 23 may be inclined with respect to the optical axis T1 of the light source 1 so that the light L2 is irradiated in a direction away from the cut line (toward the bottom of the drawing in Figure 1(a)) than the light L3.

[0037] Furthermore, since both the light L1 and the light L2 are collimated, intense light, it is preferable that the central axis T3 of the transmitting section 22 be inclined with respect to the optical axis T1 of the light source 1 so that the light L1 and the light L2 are emitted in directions that are approximately the same.

[0038] (Regarding the Shape of the Total Reflection Portion) As described above, in the optical lens 2 according to this embodiment, the optical axis T1 of the light source 1 is disposed (decentered) below the central axis T2' of the total reflection portion 23 in the drawing. Furthermore, in the optical lens 2 according to this embodiment, the central axis T2 of the total reflection portion 23 is inclined (tilted) with respect to the optical axis T1 of the light source 1. Therefore, as shown in FIG. 1A, the curvature (first curvature) of the upper portion 23a of the total reflection portion 23 is different from the curvature (second curvature) of the lower portion 23b of the total reflection portion 23. Note that in a typical optical lens, when the total reflection portion 23 is formed in a parabolic shape, the total reflection portion 23 is symmetrical with respect to the Z direction (the direction in which the optical axis T1 extends).

[0039] (Example of Arrangement of Illumination Device) FIG. 5 is a side view showing an example of arrangement of the illumination device according to the first embodiment.

[0040] 5, the lighting device 100 is disposed on the side of a road 200 and irradiates the road 200 with illumination light L10. Although not shown, a plurality of lighting devices are lined up along the road 200 (in the depth direction of the drawing). A moving object such as a car 201 is traveling on the road 200.

[0041] 5, in this embodiment, the lighting device 100 (optical lens 2) is installed so as to be tilted (specifically, at about 14° from the horizontal direction) with respect to the horizontal direction (left-right direction in the drawing). Note that the angle at which the lighting device 100 is tilted may be any angle greater than 0° and equal to or less than 45°.

[0042] In conventional lighting devices, obstacles (such as automobile 201) on the road 200 are perceived as shadows (silhouette vision). In this case, the illuminance of the road 200 needs to be increased, which narrows the illumination range of each lighting device and requires the lighting devices to be placed at close intervals. In contrast, the lighting device 100 according to this embodiment brightens the obstacles (such as automobile 201) on the road 200 so that they are perceived (reverse silhouette vision). In this case, the illuminance of the road 200 can be minimized, thereby widening the illumination range of the lighting device 100 and enabling the lighting devices to be placed at wider intervals, thereby reducing the number of lighting devices placed on the road 200. Furthermore, the energy consumption of the lighting device can be reduced. Furthermore, the lighting device can be installed at a lower position than conventional lighting devices, thereby reducing the labor required for construction, maintenance, and the like.

[0043] Furthermore, as described above, the lighting device 100 is less likely to leak light above the cut line C4 in the drawing, so by setting the cut line C4 below the driver of the car 201 traveling on the road 200, the driver is less likely to feel dazzled.

[0044] Second Embodiment Fig. 6 is a side view of an illumination device according to a second embodiment. In Fig. 6, compared to Fig. 1, a convex portion 24a (first convex portion) is formed in the center of the light exit surface 24. Specifically, the convex portion 24a is formed at a position where light L1 incident on the transmission portion 22 from the light source 1 is incident on the light exit surface 24.

[0045] The transmitting portion 22 has a convex shape (spherical, rotationally symmetric shape). If the curvature of the transmitting portion 22 becomes large, it will be affected by aberration. Therefore, by forming a convex portion 24a on the exit surface 24, the curvature of the transmitting portion 22 can be reduced, and the effect of aberration can be suppressed.

[0046] In this embodiment, if the lens diameter of the transmitting portion 22 (the size of the transmitting portion 22) is D1 and the lens diameter of the convex portion 24a (the size of the convex portion 24a) is D2, then D1≦D2≦3×D1.

[0047] 7 is a side view of an illumination device according to a third embodiment. In comparison with FIG. 1, a convex portion 24b (second convex portion) is formed on the outer peripheral edge of the light exit surface 24. Specifically, the convex portion 24b is formed at a position where the light L3 reflected by the total reflection portion 23 enters the light exit surface 24.

[0048] If the curvature of the total reflection portion 23 becomes large, it will be affected by off-axis aberration. Therefore, by forming the convex portion 24b on the light exit surface 24, the curvature of the total reflection portion 23 can be reduced, and the effect of off-axis aberration can be suppressed.

[0049] In this embodiment, when the thickness of the optical lens 2 is H and the thickness of the convex portion 24b is h, 0.01×H≦h≦0.3×H holds.

[0050] (Fourth embodiment) Fig. 8 is a diagram showing an illumination device according to a fourth embodiment. Specifically, Fig. 8(a) is a side view of the illumination device according to the fourth embodiment, and Fig. 8(b) is a diagram showing illumination light in the fourth embodiment. Fig. 8(b) is a diagram showing irradiated light when irradiated onto a wall surface or the like.

[0051] 8, compared to FIG. 1, the curvature (first curvature) of the upper portion 23a of the total reflection portion 23 is larger than the curvature (second curvature) of the lower portion 23b of the total reflection portion 23. As a result, the light L5 totally reflected by the lower portion 23a of the total reflection portion 23 is diffused over a wide range. This allows the irradiation range on the opposite side of the cut line C5 to be widened (see FIG. 8(b)).

[0052] 8, the shape of the lower part 23b of the total reflection part 23 may be the same as the shape of the lower part of the total reflection part 23 when the central axis T2 of the total reflection part 23 and the optical axis T1 of the light source 1 are located at the same position. Specifically, the shape may be the same as the shape of the lower part of the total reflection part 23 in FIG. 3(b). This allows the above-mentioned effect to be obtained.

[0053] 9A is a plan view of an illumination device according to a fifth embodiment, and FIG. 9D is a diagram showing illumination light in the fifth embodiment. Note that FIG. 9C is a diagram showing illumination light in the first embodiment, and FIGS. 9C and 9D are diagrams showing illumination light when the illumination light is irradiated onto a road 200.

[0054] 9A, compared to FIG. 1B, the light exit surface 24 is formed in a concave shape. Specifically, the light exit surface 24 has a convex portion 24c on the left side of the drawing, a convex portion 24d on the right side of the drawing, and is concave in the center.

[0055] As shown in Fig. 9C, in the first embodiment, the exit surface 24 is substantially flat, so the illumination light is emitted as parallel light and does not spread much in the horizontal direction. In contrast, in Fig. 9A, the exit surface 24 is concave, so the illumination light is diffused in the left-right direction (horizontal direction) of the drawing, and therefore, is emitted over a wide range in the horizontal direction (see Fig. 9D).

[0056] In this embodiment, when the thickness of the optical lens 2 is W and the thickness of the convex portion 24c is w, 0.01×W≦w≦0.5×W.

[0057] (Modification 1) Figures 9(b) and (e) are diagrams showing an illumination device according to Modification 1 of the fifth embodiment. Specifically, Figure 9(b) is a plan view of an illumination device according to Modification 1 of the fifth embodiment, and Figure 9(e) is a diagram showing illumination light in Modification 1 of the fifth embodiment. Note that Figure 9(e) is a diagram showing illumination light when the illumination light is irradiated onto a road 200.

[0058] In Fig. 9(b), compared to Fig. 9(a), the right side of the light exit surface 24 is formed concave. Specifically, a convex portion 24d is formed on the right side of the light exit surface 24, and the right side and the center are concave. As a result, the illumination light is diffused to the right side of the drawing, and is irradiated over a wide area on the right side of the drawing (see Fig. 9(e)). Therefore, for example, when the automobile 201 travels from the right side to the left side of the road 200, the driver is less likely to feel dazzled.

[0059] In the modified example, when the thickness of the optical lens 2 is H and the thickness of the convex portion 24d is h, 0.01×H≦h≦0.3×H.

[0060] (Modification 2) Figures 10(a) and 10(c) are diagrams showing an illumination device according to Modification 2 of the fifth embodiment. Specifically, Figure 10(a) is a plan view of an illumination device according to Modification 2 of the fifth embodiment, and Figure 10(c) is a diagram showing illumination light in Modification 2 of the fifth embodiment. Note that Figure 10(c) is a diagram showing illumination light when the illumination light is irradiated onto a road 200.

[0061] 1B, the exit surface 24 in Fig. 10A is formed in a convex shape, which causes the illumination light to be diffused in the left-right direction (horizontal direction) of the drawing, thereby irradiating a wider range in the horizontal direction (see Fig. 10C).

[0062] In this modification, when the thickness of the optical lens 2 is H and the thickness of the light exit surface 24 is h, 0.01×H≦h≦0.3×H.

[0063] (Modification 3) Figures 10(b) and (d) are diagrams showing an illumination device according to Modification 3 of the fifth embodiment. Specifically, Figure 10(b) is a plan view of an illumination device according to Modification 3 of the fifth embodiment, and Figure 10(d) is a diagram showing illumination light in Modification 3 of the fifth embodiment. Note that Figure 10(d) is a diagram showing illumination light when the illumination light is irradiated onto a road 200.

[0064] In Fig. 10(b), compared to Fig. 10(a), the left side of the light exit surface 24 is formed in a convex shape. Specifically, the light exit surface 24 has a convex portion 24e formed on the left side of the drawing, and the right side of the drawing is flat. As a result, in Fig. 10(b), the illumination light is diffused to the right side of the drawing, and is irradiated over a wide area on the right side of the drawing (see Fig. 10(d)). Therefore, for example, when the automobile 201 travels from the right side to the left side of the road 200, the driver is less likely to feel glare.

[0065] In this modification, when the thickness of the optical lens 2 is W and the thickness of the convex portion 24e is w, 0.01×W≦w≦0.5×W.

[0066] (Sixth embodiment) Fig. 11 is a diagram showing an illumination device according to a sixth embodiment. Specifically, Fig. 11(a) is a perspective view of the illumination device according to the sixth embodiment, Fig. 11(b) is a side view of the illumination device according to the sixth embodiment, Fig. 11(c) is a plan view of the illumination device according to the sixth embodiment, Fig. 11(d) is a front view of the illumination device according to the sixth embodiment, and Fig. 11(e) is a diagram showing illumination light in the sixth embodiment. Note that Fig. 11(e) is a diagram showing illumination light when the illumination light is irradiated onto a wall surface or the like.

[0067] 11 , convex portions 24 a, 24 c, and 24 d are formed on the exit surface 24 of the optical lens 2. That is, the optical lens 2 of the sixth embodiment includes the configurations of the optical lenses 2 of the second and fifth embodiments. This allows a cut line to be formed at the top of the drawing, and achieves irradiation light with a wide irradiation range in the horizontal direction (see FIG. 11( e)).

[0068] (Seventh embodiment) Fig. 12 is a diagram showing an illumination device according to a seventh embodiment. Specifically, Fig. 12(a) is a plan view of the illumination device according to the seventh embodiment, Fig. 12(b) is a front view of the illumination device according to the seventh embodiment, and Fig. 12(c) is a diagram showing illumination light in the seventh embodiment. Fig. 11(c) is a diagram showing illumination light when the illumination light is irradiated onto a road 200.

[0069] 1(b), in Fig. 12(a), multiple light sources 1 are arranged with respect to one optical lens 2. Specifically, the multiple light sources 1 are arranged in the horizontal direction (X direction). As a result, the illumination light is diffused widely in the horizontal direction, and is therefore irradiated over a wide range in the left-right direction of the drawing (see Fig. 12(c)).

[0070] Eighth Embodiment Fig. 13 is a side view showing an illumination device according to an eighth embodiment. In Fig. 13, the optical lens 2 is tilted downward compared to Fig. 1(a). This allows the cut line to be aligned horizontally, eliminating the need to tilt the illumination device itself downward when installing it. The angle at which the optical lens 2 is tilted relative to the horizontal direction may be greater than 0° and less than or equal to 45°.

[0071] (Ninth embodiment) Fig. 14 is a diagram showing an illumination device according to a ninth embodiment. Specifically, Fig. 14(a) is a plan view of the illumination device according to the ninth embodiment, and Fig. 14(b) is a diagram showing illumination light in the ninth embodiment. Fig. 14(b) is a diagram showing illumination light when the illumination light is irradiated onto a road 200.

[0072] 1(b), a cover 4 is provided on the side opposite to the exit surface 24 of the optical lens 2. The cover 4 is made of a light-transmitting material. By providing the cover 4 to the lighting device 100, the light source 1 and the optical lens 2 can be protected from flying objects (such as flying stones) from the outside.

[0073] A wave is formed on the inner surface 41 of the cover 4. This allows the illumination light to be widely diffused in the horizontal direction (see FIG. 14(b)). Note that the wave may be formed on the outer surface of the cover 4, or on both the inner and outer surfaces of the cover 4.

[0074] (Modification 1) FIG. 15A is a side view showing an illumination device according to Modification 1 of the ninth embodiment.

[0075] 15( a), an anti-reflection coating (film) 5a is formed on the surfaces of the optical lens 2 and the cover 4. The anti-reflection coating 5a is formed by alternately stacking a plurality of high refractive index materials and a plurality of low refractive index materials. The anti-reflection coating 5a is formed on the light exit surface 24 of the optical lens 2 and the inner surface 41 and outer surface 42 of the cover 4. This makes it possible to suppress light reflected on the light exit surface 24 of the optical lens 2 and the inner surface 41 and outer surface 42 of the cover 4, thereby suppressing stray light.

[0076] The anti-reflection film 5a is formed by attaching an anti-reflection film to the optical lens 2 or the like, or by performing a film in-mold process on the optical lens 2 or the like.

[0077] (Modification 2) FIG. 15B is a side view showing an illumination device according to Modification 2 of the ninth embodiment.

[0078] 15(b), a moth-eye structure 5b (microstructure) is formed on the surfaces of the optical lens 2 and the cover 4. The moth-eye structure 5b is composed of minute irregularities. The moth-eye structure 5b is formed on the entrance 21 and exit surface 24 of the optical lens 2 and the inner surface 41 of the cover 4. This makes it possible to suppress light reflected at the entrance 21 and exit surface 24 of the optical lens 2 and the inner surface 41 of the cover 4, thereby suppressing stray light.

[0079] The moth-eye structure 5b is formed when the optical lens 2 or the like is injection molded, or by processing the optical lens 2.

[0080] Tenth Embodiment Fig. 16 is a diagram showing a lens array used in an illumination device according to a tenth embodiment. Specifically, Fig. 16(a) is a perspective view of the lens array 6, Fig. 16(b) is a front view of the lens array 6, and Fig. 16(c) is a side view of the lens array 6.

[0081] As shown in Fig. 16(b), the lens array 6 has a plurality of optical lenses 2 (here, two in the X direction and six in the Y direction) arranged in an array. The optical lenses 2 are connected by a transparent plate-like member 7. Although not shown, one light source is disposed at the entrance of each optical lens 2. The lens array 6 uses the optical lenses 2 of Fig. 11 as the optical lenses 2.

[0082] 16 , multiple optical lenses 2 (multiple light sources 1) are arranged in the lighting device 100, thereby improving the illuminance of the light emitted by the lighting device 100. Furthermore, multiple optical lenses 2 are connected by a plate-like member 7, thereby improving the strength of the lighting device 100. Furthermore, the plate-like member 7 can prevent dust and other particles from entering the lighting device 100, eliminating the need for a cover and suppressing Fresnel reflection that would occur if a cover were attached.

[0083] In this embodiment, if the angle between the exit surface 24 and the plate-like member 7 is Φ1 and the angle between the convex portion 24a and the exit surface 24 is Φ2, then Φ1≦20° and Φ2≦20°.

[0084] (Modification) FIG. 17A is a front view showing a lens array used in an illumination device according to a first modification of the tenth embodiment.

[0085] 17( a), in the lens array 6, a plurality of optical lenses 2 arranged side by side in the horizontal direction overlap each other. This makes it possible to reduce the width of the illumination device 100 in the horizontal direction (X direction) without reducing the number of optical lenses, and therefore the illumination device 100 can be arranged in a narrow area.

[0086] FIG. 17B is a front view showing a lens array used in an illumination device according to a second modification of the tenth embodiment.

[0087] 17(b), in the lens array 6, a plurality of optical lenses 2 are arranged in a staggered pattern. This makes it possible to reduce the horizontal width of the illumination device 100 without reducing the number of optical lenses, and therefore the illumination device 100 can be arranged in a narrow area.

[0088] 11th Embodiment Fig. 18 is a diagram showing a lens array used in an illumination device according to an 11th embodiment. Specifically, Fig. 18(a) is a front view of an optical lens used in the lens array 6, Fig. 18(b) is a front view of an example of the lens array 6, and Fig. 18(c) is a front view of another example of the lens array 6.

[0089] As shown in FIG. 18(a), the optical lens 2 used is the optical lens 2 of FIG. 11, in which both the top and bottom ends and both the left and right ends in the drawing are cut off to form a substantially square shape.

[0090] 18( c), a plurality of optical lenses 2 (here, two in the X direction and six in the Y direction) are arranged in an array in the lens array 6. As a result, the optical lenses 2 arranged in the array do not overlap each other, and it is possible to improve the illuminance of the light emitted by the lighting device 100 while maintaining the performance of each optical lens relative to the cut line.

[0091] 18( c), in the lens array 6, a plurality of optical lenses 2 arranged side by side in the horizontal direction overlap each other. This makes it possible to reduce the width of the illumination device 100 in the horizontal direction (X direction) without reducing the number of optical lenses, and therefore the illumination device 100 can be arranged in a narrow area.

[0092] Twelfth Embodiment Fig. 19 is a diagram showing a lens array used in an illumination device according to a twelfth embodiment. Specifically, Fig. 19(a) is a perspective view of the lens array 6, and Fig. 19(b) is an enlarged perspective view of an area A1 in Fig. 19(a). Note that the lens array 6 uses the optical lenses 2 shown in Fig. 11 as the optical lenses 2.

[0093] As shown in FIG. 19( a), the lens array 6 has optical lenses 2 arranged in an array facing downward in the drawing. Also, as shown in FIG. 19( b), a slit S is formed between the optical lenses 2. Specifically, the slit S is formed between the total reflection portion 23 of the optical lens 2 arranged at the top of the drawing and the total reflection portion 23 of the optical lens 2 arranged at the bottom of the drawing. This prevents light from the light source 1 from entering between the optical lenses 2, thereby suppressing stray light. The optical lenses 2 arranged at the top and bottom of the drawing are connected at the bottom end of the exit surface 24 of the optical lens 2 at the top of the drawing and the bottom end of the total reflection portion 23 of the optical lens 2 at the bottom of the drawing.

[0094] As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0095] The optical lens of the present disclosure can be used, for example, in a lighting device that irradiates a road on which automobiles travel with illumination light.

[0096] REFERENCE SIGNS LIST 1 light source 2 optical lens 21 incident port 21a side portion 22 transmission portion 23 total reflection portion 23a upper portion 23b lower portion 24 emission surface 24a to 24e convex portion 3 housing 4 cover 5a anti-reflection film 5b moth-eye structure (microstructure) 6 lens array 7 plate-shaped member 100 lighting device 200 road 201 automobile (moving body)

Claims

1. An optical lens having a transmissive portion formed at a position facing a light source in the optical axis direction, and a total reflective portion formed on a side of the optical lens, wherein the central axis of the transmissive portion is not positioned on the optical axis of the light source, and the central axis of the total reflective portion is not positioned on the optical axis of the light source and is inclined with respect to the optical axis.

2. The optical lens according to claim 1, wherein the optical axis of the light source and the central axis of the total reflection portion are arranged so that, of the first light reflected at a first point that is a short focal distance from the light source, the light at one end as viewed from the side and the second light reflected at a second point that is a long focal distance from the light source, the light at one end as viewed from the side substantially coincide with the cut line; the central axis of the total reflection portion is tilted with respect to the optical axis of the light source so that the third light reflected at the side of the entrance of the optical lens and the fourth light reflected by the total reflection portion are irradiated in a direction that substantially coincides with the cut line, or the fourth light is irradiated in a direction that is farther from the cut line than the third light; and the central axis of the transmission portion is tilted with respect to the optical axis of the light source so that the fifth light that has transmitted through the transmission portion and the fourth light are irradiated in a direction that substantially coincides with the cut line.

3. The optical lens according to claim 1, further comprising an exit surface that emits light incident on the optical lens, wherein a first convex portion is formed in the center of the exit surface.

4. The optical lens according to claim 1, further comprising an exit surface that emits light incident on said optical lens, said exit surface having a second convex portion formed on the outer peripheral edge thereof.

5. The optical lens of claim 1, wherein the total reflection portion has a first curvature, which is the curvature on one side in a first direction perpendicular to the optical axis direction, that is different from a second curvature, which is the curvature on the other side in the first direction, when the lens is viewed from the side.

6. The optical lens of claim 5, wherein the second curvature is greater than the first curvature.

7. The optical lens according to claim 5, wherein the second curvature is a curvature when the central axis of the total reflection portion coincides with the optical axis of the light source.

8. The optical lens according to claim 1, further comprising an exit surface that emits light incident on the optical lens, said exit surface being formed in a concave shape when viewed in a plan view.

9. The optical lens according to claim 1, further comprising an exit surface that emits light incident on the optical lens, said exit surface being formed in a convex shape when viewed in a plan view.

10. A light source device comprising the optical lens according to claim 1 and the light source.

11. An illumination device comprising the optical lens according to claim 1 and the light source.

12. An illumination device comprising the optical lens according to claim 5 and the light source, wherein the optical axis of the light source is inclined towards the other side in the first direction with respect to the horizontal when the illumination device is viewed from the side.

13. A lighting device comprising the optical lens according to claim 8 and the light source, the lighting device irradiating light onto a road surface along which a moving object travels from the other side to the one side in the second direction.

14. A lighting device comprising: the optical lens according to claim 1; the light source; and a cover provided on the side of the optical lens opposite the light exit surface.

15. The lighting device according to claim 14, wherein a microstructure is formed on the surface of at least one of the optical lens and the cover.

16. A lighting device comprising a lens array in which a plurality of optical lenses according to claim 1 are formed in an array, and the light source.

17. The lighting device according to claim 16, wherein a slit is formed between adjacent optical lenses.

18. An optical lens having a transmissive portion formed at a position facing a light source in the optical axis direction, and a total reflection portion formed on a side of the optical lens, wherein the central axis of the transmissive portion is not positioned on the optical axis of the light source, and the total reflection portion has a first curvature, which is the curvature on one side in a first direction perpendicular to the optical axis direction, and a second curvature, which is the curvature on the other side in the first direction, when the lens is viewed from the side.

19. An illumination device comprising the optical lens of claim 18 and the light source, wherein when the total reflection portion is formed in a parabolic shape, the light source is not positioned at the focus of the total reflection portion.

20. An illumination device comprising the optical lens of claim 18 and the light source, wherein the optical axis of the light source is inclined toward the other side in the first direction with respect to the horizontal when the illumination device is viewed from the side.

Images