WO2019167444A1

WO2019167444A1 - Optical member and illumination device

Info

Publication number: WO2019167444A1
Application number: PCT/JP2019/000693
Authority: WO
Inventors: 良平高山
Original assignee: ミネベアミツミ株式会社
Priority date: 2018-03-02
Filing date: 2019-01-11
Publication date: 2019-09-06
Also published as: JP2019153474A

Abstract

The optical member according to an embodiment is provided with a reflection portion (23) and an exit-side refraction portion (26). The reflection portion (23) is formed in an outside region (Ra) of an incident plane (21) on which light from a light source (10) is incident, said outside region (Ra) forming the outside away from a position facing the light source (10), and reflects incident light (L) to control light distribution. The exit-side refraction portion (26) is formed in an inside region (Rc) of an exit plane (22) that is the rear surface of the incident plane (21), said inside region (Rc) forming the inside of the outside region (Ra) when viewed from the incident plane (21), and refracts the incident light (L) to control the light distribution.

Description

Optical member and lighting device

The present invention relates to an optical member and a lighting device.

Conventionally, in a lighting device, a so-called compound Fresnel lens in which a reflecting prism is formed in an outer region of an incident surface on which light from a light source is incident and a refractive prism is formed in an inner region of the outer surface of the incident surface. Is known to be used as an optical member (see, for example, Patent Document 1).

JP 2011-11086 A

However, it cannot be said that the conventional optical member and the lighting device as described above are sufficiently considered for glare (glare). Accordingly, the inventors of the present invention have studied that the light incident on the reflecting prism and the refractive prism existing in the vicinity of the boundary between the reflecting prism and the refractive prism is not appropriately subjected to light distribution control, and is a surface that the illumination device irradiates (hereinafter referred to as “lighting”). It has been found that glare is generated by the light that is not directed to the irradiation surface.

The present invention has been made in view of the above, and an object thereof is to provide an optical member and a lighting device that can reduce glare.

In order to solve the above-described problems and achieve the object, an optical member according to one embodiment of the present invention is provided in an outer region that is an outer side away from a position facing the light source on an incident surface on which light from the light source is incident. A reflection portion that reflects the incident light and controls light distribution; and an exit surface that is the back surface of the entrance surface and is formed in an inside region that is inside the outside region when viewed from the entrance surface. And an exit-side refracting unit that refracts the light and controls light distribution.

According to one embodiment of the present invention, glare can be reduced.

FIG. 1 is an explanatory diagram of an optical member and a lighting device according to the first embodiment. FIG. 2A is a schematic plan view showing the optical member according to the first embodiment. FIG. 2B is a schematic bottom view showing the optical member according to the first embodiment. 3A is a cross-sectional view taken along line A1-A1 in FIG. 2A. FIG. 3B is an enlarged view of a portion A2 in FIG. 3A. 4A is a cross-sectional view along B1-B1 in FIG. 2A. FIG. 4B is an enlarged view of a portion B2 in FIG. 4A. FIG. 5A is a cross-sectional view taken along line C1-C1 in FIG. 2A. FIG. 5B is an enlarged view of a portion C2 in FIG. 5A. FIG. 6 is a graph showing the relationship between the light irradiation angle and the luminous intensity ratio in the illumination device. FIG. 7A is a graph showing the relationship between the light irradiation angle and the intensity in the case of this example in part D of FIG. FIG. 7B is a graph showing the relationship between the light irradiation angle and the intensity in the case of the comparative example in part D of FIG. FIG. 8 is an explanatory diagram of an optical member and a lighting device according to the second embodiment. FIG. 9A is a schematic plan view showing an optical member according to a modification. FIG. 9B is a schematic bottom view showing an optical member according to a modification.

Hereinafter, the optical member and the illumination device according to the embodiment will be described with reference to the drawings. In addition, this invention is not limited by embodiment described below. Further, the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation. In addition, there may be a case where the dimensional relationships and ratios are different between the drawings.

<First Embodiment>
First, the outline of the optical member 20 and the illumination device 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram of the optical member 20 and the illumination device 1 according to the first embodiment. In FIG. 1, side surfaces (partial cross sections) of the optical member 20 and the lighting device 1 are shown. As shown in FIG. 1, the lighting device 1 includes a light source 10 and an optical member 20. The lighting device 1 may further include a reflecting mirror that integrally covers the light source 10 and the optical member 20.

The light source 10 emits light L toward an incident surface 21 described later of the optical member 20. The light source 10 is a so-called point light source that emits light from one point, and is, for example, an LED (Light Emitting Diode). The light source 10 includes, for example, a light emitting element such as an LED chip, and has a light emitting surface 11 that emits light L.

The optical member 20 is a lens sheet formed in a disk shape with a predetermined diameter using, for example, a transparent resin (for example, acrylic resin). The optical member 20 is arranged around a position P facing the center O of the light source 10 so that a predetermined distance is formed between the incident surface 21 that is a surface facing the light source 10 and the light emitting surface 11 of the light source 10. The In other words, the optical member 20 is arranged such that the center of the incident surface 21 and the optical axis AX of the light source 10 coincide with each other.

The optical member 20 includes an incident surface 21 and an exit surface 22 that is the back surface of the incident surface 21. Light L from the light source 10 is incident on the incident surface 21. The incident surface 21 includes a reflecting portion 23, an incident side refracting portion 24, and a flat surface 25.

The reflecting portion 23 is a position where a plurality of reflecting prisms (also referred to as TIR (Total Internal Reflection) prisms) 23a are viewed from the incident surface 21, that is, the center of the incident surface 21 in plan view (hereinafter referred to as a center position). It is formed concentrically around the center position P in the outer region Ra which is the outer side away from P. The reflection unit 23 performs light distribution control by reflecting the light L from the light source 10 at a reflection angle set by each of the plurality of reflection prisms 23a. Details of the reflecting prism 23a in the reflecting section 23 will be described later with reference to FIGS. 3A and 3B.

The incident-side refracting portion 24 has a circular shape around a central position P where a plurality of refracting prisms (also referred to as Fresnel prisms) 24a are located on the inner side of the outer region Ra where the reflecting portion 23 is formed in plan view (or bottom view). The region Rb is formed concentrically around the center position P. The incident-side refracting unit 24 performs light distribution control by refracting the light L from the light source 10 at a refraction angle set by each of the plurality of refraction prisms 24a. The details of the refraction prism 24a in the incident side refraction unit 24 will be described later with reference to FIGS. 4A and 4B.

The flat surface 25 is formed in an annular region between the outer region Ra where the reflecting portion 23 is formed and the region Rb where the incident side refracting portion 24 is formed.

The optical member 20 is provided with a concentric prism pattern including a reflecting prism 23a of the reflecting portion 23 and a refractive prism 24a of the incident side refracting portion 24 on the incident surface 21, so-called TIR-Fresnel pattern. Light distribution can be controlled toward the irradiation surface of the illumination device 1. Further, the optical member 20 includes the prism pattern (TIR-Fresnel pattern) as described above, so that the light distribution control is made uniform with respect to the circumferential direction of the incident surface 21 while suppressing a decrease in the light amount of the light L. It can be carried out.

The emission surface 22 is a surface from which most of the light L is emitted out of the surfaces from which the light L incident on the incident surface 21 from the light source 10 is emitted. The exit surface 22 includes an exit side refracting portion 26, a central flat surface 27, and an outer flat surface 28.

The exit side refracting unit 26 includes a plurality of refracting prisms (also referred to as Fresnel prisms) 26a on the exit surface 22 as viewed from the entrance surface 21, that is, a part of the outer region Ra where the reflecting unit 23 is formed in plan view. Are formed concentrically around the center position P of the incident surface 21 in the inner region Rc that is inside the outer region Ra while overlapping. The exit side refracting unit 26 performs light distribution control on the light (illumination light) L by refracting the light L incident from the incident surface 21 at a refraction angle set by each of the plurality of refraction prisms 26a. Details of the refraction prism 26a in the exit side refraction section 26 will be described later with reference to FIGS. 5A and 5B.

The central flat surface 27 is formed in a region corresponding to the periphery of the center position P on the incident surface 21 when viewed from the incident surface 21, that is, in plan view. The region where the central flat surface 27 is formed corresponds to the region Rb where the incident-side refracting portion 24 is formed on the incident surface 21.

The outer flat surface 28 is formed in an annular region that is outside the inner region Rc where the exit-side refracting portion 26 is formed.

Next, referring to FIG. 2A and FIG. 2B, the outer region Ra in which the reflecting portion 23 is formed on the incident surface 21 of the optical member 20, the region Rb in which the incident-side refracting portion 24 is formed, and the exit surface of the optical member 20. The relationship of the inner region Rc in which the exit side refracting portion 26 is formed will be further described.

FIG. 2A is a schematic plan view showing the optical member 20 according to the first embodiment, and is a view of the optical member 20 as viewed from the incident surface 21 side. FIG. 2B is a schematic bottom view showing the optical member 20 according to the first embodiment, and is a view of the optical member 20 as viewed from the emission surface 22 side. 2A and 2B, the above-described regions Ra, Rb, and Rc are hatched.

As shown in FIG. 2A, the outer peripheral portion on the outer side of the incident surface 21 is an annular outer region Ra in which the reflecting portion 23 is formed. Further, the periphery of the center position P that is inside the outer region Ra on the incident surface 21 is a circular region Rb in which the incident-side refracting portion 24 is formed. An annular region (flat region) in which the flat surface 25 is formed is formed between the outer region Ra in which the reflecting portion 23 is formed and the region Rb in which the incident-side refracting portion 24 is formed.

As shown in FIG. 2B, a space between the outer region and the inner region on the exit surface 22 is an annular inner region Rc in which the exit-side refracting portion 26 is formed. In the exit surface 22, a region corresponding to the region Rb in which the incident-side refracting portion 24 is formed on the incident surface 21 is a circular region (flat region) in which the central flat surface 27 is formed. As shown in FIGS. 2A and 2B, the region Rb where the incident-side refracting portion 24 is formed corresponds to the region where the central flat surface 27 is formed in plan view. The outer region Ra where the reflecting portion 23 is formed corresponds to a region where the outer flat surface 28 is formed in a plan view.

Further, as shown in FIGS. 2A and 2B, the inner region Rc where the emission-side refracting portion 26 is formed on the emission surface 22 has an outer peripheral portion that overlaps with an inner peripheral portion of the outer region Ra of the incident surface 21 in plan view. Yes. In addition, the inner region Rc in which the exit-side refracting portion 26 is formed is separated from the region Rb in which the inner peripheral portion is formed with the incident-side refracting portion 24 in the incident surface 21. Note that the inner region Rc and the region Rb in which the incident-side refracting portion 24 is formed may be continuous in plan view.

Next, the reflecting prism 23a of the reflecting portion 23 on the incident surface 21 will be described with reference to FIGS. 3A and 3B. 3A is a cross-sectional view taken along line A1-A1 in FIG. 2A. FIG. 3B is an enlarged view of a portion A2 in FIG. 3A. FIG. 3B illustrates the light L reflected by the reflecting prism 23a. As shown in FIG. 3A, in the incident surface 21, the reflecting portion 23 is formed by a plurality of reflecting prisms 23 a continuing from the outside to the inside of the incident surface 21, that is, continuing in the radial direction of the incident surface 21. Thus, irregularities are formed on the incident surface 21.

Here, as shown in FIG. 3B, the reflecting prism 23a reflects the light L from the light source 10 (see FIG. 1) incident on the inner surface 231a toward the outer side inside the reflecting prism 23a. In 232a, for example, the light is reflected in a direction parallel to the optical axis AX (see FIG. 1), or in a direction spreading outward while suppressing the spread of the incident light L. The direction of the light L reflected by the reflecting prism 23a is not limited to these. The reflecting prism 23a may reflect the incident light L in a direction crossing the optical axis AX, for example, depending on the application. The inclination angle of the reflecting surface 232a is set according to, for example, the distance from the light source 10 or the angle with respect to the light source 10. The tilt angle is a rising angle from the incident surface 21 with the incident surface 21 being 0 degrees.

Next, the refraction prism 24a of the incident side refraction part 24 on the incident surface 21 will be described with reference to FIGS. 4A and 4B. 4A is a cross-sectional view along B1-B1 in FIG. 2A. FIG. 4B is an enlarged view of a portion B2 in FIG. 4A. FIG. 4B illustrates light L refracted by the refraction prism 24a. As shown in FIG. 4A, the incident-side refracting unit 24 in the incident surface 21 has a plurality of refractive prisms 24 a continuous from the outside to the inside of the incident surface 21, that is, continuous in the radial direction of the incident surface 21. As a result, irregularities are formed on the incident surface 21.

The refraction prism 24a of the incident side refraction part 24 is formed inside the refraction prism 26a of the emission side refraction part 26 on the emission surface 22 with a predetermined length d1 in plan view.

Here, as shown in FIG. 4B, the refraction prism 24a is configured so that the light L from the light source 10 (see FIG. 1) is parallel to the optical axis AX (see FIG. 1) on the refraction surface 241a facing outward. The light is refracted in such a direction as to be spread outward or while suppressing the spread from the incident light L. The direction of the light L refracted by the refraction prism is not limited to these. The inclination angle of the refracting surface 241a is set according to the distance from the center position P (see FIG. 1), for example. The surface facing the inside of the refraction prism 24a is a surface that does not contribute to the function of the refraction prism 24a.

Here, for example, in the case of a Fresnel lens having a reflecting portion in the outer region of the incident surface and a refracting portion in the inner region of the incident surface, and the reflecting portion and the refracting portion are continuous, the vicinity of the boundary between the reflecting portion and the refracting portion. In some cases, the light distribution control is not properly performed in the reflecting prism and the refraction prism existing in FIG. In other words, light distribution control may not be performed appropriately in the reflective portion as the inner reflective prism and in the refractive portion as the outer refractive prism.

Specifically, the inner reflecting prism is an angle at which the light from the light source stands more than the outer side, that is, an angle approaching the angle (0 degree) of the optical axis (the optical axis is set to 0 degree, rising from the optical axis). Therefore, the light incident on the reflecting prism from the surface facing inward may not be incident on the reflecting surface and the traveling direction may not be appropriately controlled. In addition, the setting of the light reflection angle by the reflecting surface may be limited. Note that it may be difficult to set the reflecting surface in the reflecting prism so as to appropriately reflect light incident at a standing angle.

In addition, the outer refractive prism has an angle at which light from the light source lies down from the inner side, that is, an angle away from the optical axis angle (0 degree) (the rising angle from the optical axis when the optical axis is 0 degree). Since the light is incident, the possibility that light is incident on the inwardly facing surface that does not function as a refractive prism is increased. As described above, light that has not been subjected to appropriate light distribution control in the inner reflecting prism in the reflecting portion and the outer refractive prism in the refracting portion becomes light that does not go to the irradiation surface of the illumination device, so-called leakage light. For this reason, in this embodiment, the exit surface 22 of the optical member 20 is arranged on the exit side so as to correspond to the light L incident in the vicinity of the boundary between the reflecting portion and the refracting portion where leakage light, which is likely to cause glare, is likely to occur. A refracting portion 26 is formed. When a refracting prism is provided on the exit surface, light can be directly incident on the refracting surface (outer inclined surface) regardless of the rising angle from the optical axis, and the rising surface is likely to generate leakage light on the incident surface side. This is because light distribution control is possible even at an angle (that is, generation of leakage light can be suppressed). In the present embodiment, a flat region where no prism is formed is formed between the outer (outer region Ra) reflecting portion 23 and the inner (region Rb) incident side refracting portion 24 on the incident surface 21 of the optical member 20.

Next, the exit-side refracting portion 26 on the exit surface 22 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a cross-sectional view taken along line C1-C1 in FIG. 2A. FIG. 5B is an enlarged view of a portion C2 in FIG. 5A. 5A and 5B illustrate the light L refracted by the refraction prism 26a. As shown in FIG. 5A, the exit-side refracting unit 26 on the exit surface 22 has a plurality of refractive prisms 26 a continuous from the outside to the inside of the exit surface 22, that is, continuous in the radial direction of the exit surface 22. By doing so, irregularities are formed on the emission surface 22.

The exit side refracting portion 26 (a plurality of refracting prisms 26a) on the exit surface 22 is formed inside the reflecting portion 23 on the entrance surface 21 in plan view. Further, in the present embodiment, the exit-side refracting portion 26 (plurality of refraction prisms 26a) on the exit surface 22 has an outer peripheral portion of a predetermined length d2 with respect to the inner peripheral portion of the reflecting portion 23 on the entrance surface 21 in plan view. overlapping. As shown in FIG. 5A, the outer region Ra (see FIG. 1) in which the reflecting portion 23 is formed and the inner region Rc (see FIG. 1) in which the emitting side refracting portion 26 is partially overlapped with each other. As described above, the light L that has not been subjected to the light distribution control by the reflecting unit 23 or the incident-side refracting unit 24, that is, the light L that has passed through the flat region (flat surface 25) inside the reflecting unit 23, Light distribution can be controlled by being captured by the refraction prism 26a.

Here, as shown in FIG. 5B, the refractive prism 26a includes an outer inclined surface 261a and an inner inclined surface 262a. The outer inclined surface 261 a is a surface inclined toward the outer side of the emission surface 22. The inner inclined surface 262a is a surface inclined toward the inner side of the emission surface 22. The inner inclined surface 262a is also a surface that does not contribute to the function of the refraction prism 26a.

In the plurality of refractive prisms 26a, for example, the inclination angle of the outer inclined surface 261a is such that the outer inclined surface 261a closest to the center position P (see FIGS. 2A and 2B) of the incident surface 21 is the smallest with respect to the emission surface 22. And set so as to increase as the distance from the center position P increases. That is, the inclination angle of the outer inclined surface 261 a is the largest inclination angle with respect to the emission surface 22 at the outer inclined surface 261 a farthest from the center position P.

Further, in the plurality of refraction prisms 26a, the inclination angles of the inner inclined surfaces 262a are all set to the same inclination angle. However, the inner inclined surface 262a closest to the center position P (see FIGS. 2A and 2B) of the incident surface 21 is set so as to be the largest including the right angle with respect to the emission surface 22, and the further away from the center position P, the greater the distance. You may set so that it may become small. That is, the inclination angle of the inner inclined surface 262 a may be such that the inner inclined surface 262 a farthest from the center position P is the smallest inclination angle with respect to the emission surface 22.

The refracting prism 26a, for example, refracts light (light that has passed through the flat surface 25) L that has not passed through the reflecting prism 23a (see FIG. 5A) by the outer inclined surface 261a so as to travel toward the irradiation surface as effective light L1. Control light distribution. In this case, the light L2 that has passed through the outer inclined surface 261a is incident on the inner inclined surface 262a of the adjacent refractive prism 26a and becomes leaked light, as illustrated by the two-dot broken line in the figure, as described above. Can be suppressed.

Next, optical characteristics of the illumination device 1 (optical member 20) will be described with reference to FIGS. 6 to 7B. FIG. 6 is a graph showing the relationship between the light irradiation angle and the light intensity ratio in the lighting device 1. FIG. 7A is a graph showing the relationship between the light irradiation angle and the intensity in the case of this example in part D of FIG. FIG. 7B is a graph showing the relationship between the light irradiation angle and the intensity in the case of the comparative example in part D of FIG.

As shown in FIG. 6, for example, the light emitted from the illumination device 1 (the optical member 20) (hereinafter referred to as illumination light) is, for example, luminous intensity at a position where the irradiation angle is 0 degrees, that is, at the center position of the irradiation surface. The ratio is about 100%, the highest, and the luminous intensity ratio is about 0% when the irradiation angle is about ± 90 degrees.

Here, as described above, when light (leakage light) that is not directed to the irradiation surface is generated among the light emitted from the optical member 20, when the user views the illumination light from the direction of the leakage light, for example, You may feel glare. This is called glare.

As shown in FIG. 7A, in the case of this example (this embodiment), the intensity (radiation intensity) of the illumination light does not increase again even when the irradiation angle increases. On the other hand, as shown in FIG. 7B, in the case of a comparative example using a composite Fresnel lens that does not have the configuration of this example, the illumination intensity is high at a position where the irradiation angle is around 40 degrees, for example. Therefore, the user who sees from this direction may feel glare.

According to the optical member 20 according to the first embodiment, the exit-side refracting portion 26 (refractive prism 26a) is formed on the exit surface 22 (easy to perform light distribution control) corresponding to the position where the leakage light L2 is likely to be generated. Therefore, the light distribution control can be reliably performed on the emission surface 22, and the generation of the leakage light L2 can be suppressed. And glare can be reduced by suppressing leak light L2. For example, when the reflecting portion and the refracting portion are continuous on the incident surface 21, leakage light L2 is likely to be generated near the boundary between the reflecting portion and the refracting portion, but the optical member 20 according to the first embodiment. Accordingly, it is possible to perform light distribution control corresponding to such a position. Further, according to the optical member 20 according to the first embodiment, the space between the reflecting portion 23 and the incident side refracting portion 24 on the incident surface 21 is a flat region (flat surface 25), and the flat surface 25 on the emitting surface 22 is formed. Since the exit side refracting portion 26 is formed in the corresponding region (inner region Rc), the light L that has passed through the flat surface 25 can be captured and light distribution control can be performed.

Further, in this case, since the exit side refracting portion 26 is formed by specifying the position where the glare is likely to occur, the influence on the optical characteristics is small, so that the glare can be reduced while suppressing the deterioration of the optical characteristics.

Further, since the central region of the emission surface 22 (the region corresponding to the periphery of the center position P of the incident surface 21) is a flat region by the central flat surface 27, the loss of the light L is large in the outer region Ra of the incident surface 21. Since the exit-side refracting portion 26 is formed only at a position corresponding to the inner peripheral portion, the influence on the optical characteristics can be suppressed to be small. Thereby, the glare can be reduced while suppressing the deterioration of the optical characteristics.

Further, as described above, since the outer region Ra and the inner region Rc partially overlap, the light L that has passed through the flat region (flat surface 25) inside the reflecting portion 23 on the incident surface 21, that is, The light L that has not been subjected to the light distribution control by the reflection unit 23 or the incident-side refracting unit 24 can be captured by the refractive prism 26a of the exit-side refracting unit 26 to control the light distribution.

Even if the region Rb in which the incident-side refracting portion 24 is formed and the inner region Rc in which the emitting-side refracting portion 26 is formed are separated in plan view, the region Rb in which the incident-side refracting portion 24 is formed and the emitting side. Light L that has passed between the inner region Rc in which the refracting portion 26 is formed can be captured by the emission-side refracting portion 26 and light distribution can be controlled.

In addition, since the incident-side refracting portion 24 is formed on the incident surface 21, for example, compared with a case where only the reflecting portion 23 is formed on the incident surface 21 (specifically, high intensity and intensity) Characteristics such as excellent uniformity).

Moreover, according to the illuminating device 1 which concerns on 1st Embodiment, a glare can be reduced, providing the above-mentioned optical member 20, suppressing the fall of an optical characteristic.

In the first embodiment described above, the region Rb where the incident-side refracting portion 24 is formed and the inner region Rc where the emitting-side refracting portion 26 is formed are separated by a predetermined length d1 in a plan view of the optical member 20. However, for example, the region Rb in which the incident-side refracting portion 24 is formed and the inner region Rc may be continuous in plan view. Even in such a configuration, the exit-side refracting portion 26 of the exit surface 22 functions to reduce glare while suppressing a decrease in optical characteristics.

In the first embodiment described above, on the exit surface 22, the exit side refracting portion 26 is formed on the inner side of the outer region Ra while the outer periphery overlaps the inner periphery of the outer region Ra of the entrance surface 21. However, even if the exit side refracting portion 26 is formed on the entire exit surface 22, glare can be reduced.

<Second Embodiment>
Next, the optical member 30 and the illumination device 100 according to the second embodiment will be described with reference to FIG. FIG. 8 is an explanatory diagram of the optical member 30 and the illumination device 100 according to the second embodiment. Note that, in the second embodiment described below, the same or equivalent portions as those in the first embodiment described above may be denoted by the same reference numerals and description thereof may be omitted.

As shown in FIG. 8, in the illumination device 100, the optical member 30 includes an entrance surface 31 and an exit surface 32. The incident surface 31 includes a reflecting portion 33 and a flat surface 34. The reflecting portion 33 has a plurality of reflecting prisms with a center position in an annular outer region Ra that is outside the center position P of the incident surface 21 when seen from the incident surface 31 when the optical member 30 is viewed from the incident surface 31. It is formed concentrically around P. The reflection unit 33 performs light distribution control by reflecting the light L from the light source 10 at a set reflection angle.

The flat surface 34 is formed in a circular region on the inner side of the outer region Ra where the reflecting portion 33 is formed.

The exit surface 32 includes an exit-side refracting portion 35 and an outer flat surface 36. The exit-side refracting portion 35 is formed on the exit surface 32 in a circular inner region Rd that is partially inside the outer region Ra while partially overlapping the outer region Ra where the reflecting portion 33 is formed in plan view (or bottom view). It is formed concentrically around the center position P of the incident surface 31. Note that the inner region Rd where the emission-side refracting portion 35 is formed may not overlap the outer region Ra in plan view. The outer flat surface 36 is formed in an annular region that is outside the emission-side refracting portion 35.

According to the optical member 30 according to the second embodiment, since the exit-side refracting portion 35 is formed on the exit surface 32 so as to include a region corresponding to a position where light leakage is likely to occur, light distribution on the exit surface 32 Control can be performed, and the occurrence of leakage light can be suppressed. Moreover, glare can be reduced by suppressing leakage light.

Also in the optical member 30 according to the second embodiment, the outer region Ra and the inner region Rd partially overlap each other, so that a flat region (flat surface 34) inside the reflecting portion 33 on the incident surface 31. The light L that has passed through the light beam, that is, the light L that has not been subjected to the light distribution control by the reflection unit 33, can be captured by the refractive prism of the exit side refraction unit 35 and the light distribution can be controlled.

Moreover, according to the illuminating device 100 which concerns on 2nd Embodiment, by providing the above-mentioned optical member 30, a glare can be reduced, suppressing the fall of an optical characteristic.

<Modified example of optical member>
Next, a modified example of the optical member (optical member 40) will be described with reference to FIGS. 9A and 9B. FIG. 9A is a schematic plan view showing an optical member 40 according to a modification, and is a view of the optical member 40 as viewed from the incident surface 41 side. FIG. 9B is a schematic bottom view showing the optical member 40 according to the modification, and is a view of the optical member 40 as seen from the emission surface 22 side.

9A and 9B, the region where the reflecting portion 43 and the incident-side refracting portion 44 are formed on the incident surface 41 and the region where the emitting-side refracting portion 46 is formed on the emitting surface 42 are hatched. .

As shown in FIGS. 9A and 9B, the optical member 40 according to the modified example includes a reflecting portion (a plurality of reflecting prisms) 43 and an incident-side refracting portion (a plurality of refraction prisms) 44 on the incident surface 41, and an exit on the exit surface 42. This is a so-called linear Fresnel lens in which side refracting portions (a plurality of refraction prisms) 46 are formed in parallel straight lines.

As shown in FIG. 9A, the incident surface 41 includes a reflecting portion 43, an incident-side refracting portion 44, and a flat surface 45. The reflecting portion 43 is formed symmetrically in the left-right direction in the figure with the center position P as the center in the outer region that is the outer side of the incident surface 41. The incident-side refracting portion 44 includes a center position P in a region inside the reflecting portion 43, and is formed symmetrically with respect to the center position P, for example, in the left-right direction in the drawing.

The flat surface 45 is formed in a region between the outer region where the reflecting portion 43 is formed and the region where the incident side refracting portion 44 is formed. That is, such a region becomes a flat region.

As shown in FIG. 9B, the exit surface 42 includes an exit-side refracting portion 46, a central flat surface 47, and an outer flat surface 48. The exit side refracting portion 46 is formed in an inner region that is seen from the incident surface 41, that is, in an inner region that is partially overlapped with an outer region of the reflecting portion 43 on the incident surface 41 in plan view. It is a thing. Further, the inner region where the exit-side refracting portion 46 is formed is separated from the region where the incident-side refracting portion 44 is formed on the incident surface 41. The inner region where the exit-side refracting portion 46 is formed may not overlap the outer region where the reflecting portion 43 is formed in a plan view (or a bottom view), and the exit-side refracting portion 46 is formed. The inner region may be continuous from the region where the incident side refracting portion 44 is formed on the incident surface 41.

The central flat surface 47 is formed in a region corresponding to the region where the incident side refracting portion 44 is formed on the incident surface 41. That is, such a region becomes a flat region. The outer flat surface 48 is formed in a region outside the emission side refracting portion 46. That is, such a region is also a flat region.

According to the optical member 40 according to the modified example, since the exit-side refracting portion 46 is formed on the exit surface 42 so as to correspond to a position where light leakage is likely to occur, light distribution control can be performed on the exit surface 42, The generation of light leakage can be suppressed. Moreover, glare can be reduced by suppressing leakage light.

Also in the optical member 40 according to the modified example, since the exit side refracting portion 46 is formed by specifying the position where the glare is likely to occur, the influence on the optical characteristics is small, so that the glare is suppressed while suppressing the deterioration of the optical characteristics. Can be reduced.

In the case of the illumination device including the optical member 40 according to the modified example, the light source may be the same point light source as that in the first and second embodiments described above, or the reflection unit 43 and each refraction unit. A linear light source extending in the extending direction of the

prisms

44 and 46 may be used.

Further, the present invention is not limited by the above embodiment. What was comprised combining each component mentioned above suitably is also contained in this invention. Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

1 illumination device, 10 light source, 20 optical member, 21 entrance surface, 22 exit surface, 23 reflection portion, 24 entrance side refraction portion, 26 exit side refraction portion, 27 central flat surface, L light, P position, Ra outer region, Rb area, Rc inner area

Claims

A reflection portion that is formed in an outer region that is outside the position facing the light source on an incident surface on which light from the light source is incident, and that reflects the incident light to control light distribution;
An exit-side refracting unit that is formed in an inner region that is an inner side of the outer region when viewed from the entrance surface on the exit surface that is the back surface of the entrance surface, and that refracts incident light to control light distribution. Element.
2. The optical member according to claim 1, further comprising a central flat surface formed in a region corresponding to a periphery of a position facing the light source on the incident surface on the emission surface.
The optical member according to claim 2, further comprising an incident-side refracting portion formed in a region corresponding to the central flat surface on the exit surface on the entrance surface.
The optical member according to claim 3, wherein the inner region and the region where the incident-side refracting portion is formed are separated from the incident surface.
The optical member according to any one of claims 1 to 4, wherein the outer region and the inner region partially overlap each other when viewed from the incident surface.
An optical member according to any one of claims 1 to 5;
An illumination device comprising: the light source that emits light toward the incident surface.