Light distribution control lens and lighting device equipped with light distribution control lens

Abstract

To provide a light distribution control lens with which, while reducing lenses to one, it is possible to obtain the necessary flux of light, even when a lens diameter is kept within a prescribed dimension.SOLUTION: A light distribution control lens for controlling the distribution of light emitted by a light source and having an incidence plane which light enters and an emission plane from which light emits has a main recess formed so as to recess from a bottom face to a top face side. The incidence plane is provided on the bottom face side so as to face the light source, and the emission plane is provided upward of and lateral to the main recess in a wider range than the main recess and has a first face provided on the top face and inclined to come close to the light source as it goes from a center axis of the light distribution control lens to the radially outside, a second face provided upward from the first face on the radially outside and inclined to move away from the light source as it goes toward the radially outside, a third face provided upward from the second face on the radially outside and inclined to come close to the light source as it goes toward the radially outside, and a fourth face provided sideward from the third face on the radially outside and having a torus-like curved plane.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a light distribution control lens that controls the distribution of light emitted by a light source, and an illumination device including this light distribution control lens. [Background technology]

[0002] The JIL standard (JIL5501) stipulates that a partition wall must be provided when placing an emergency light alongside a regular light source. According to this, when placing an emergency light alongside a regular light source, a partition wall must be provided between the emergency light and the regular light source, and the emergency light lens must not exceed the height of the partition wall.

[0003] As a lens shape that meets these constraints, a structure like that shown in Patent Document 1 has been considered. However, with this structure, there is a risk that wide-angle light will be blocked by the partition wall, making it impossible to obtain the required luminous flux. Therefore, two lenses of the same shape are used to obtain the required luminous flux. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7258512 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, in order to obtain the required luminous flux with one lens, it is necessary to use an LED with a larger light source size. However, with the lens shape of Patent Document 1, the lens diameter must be increased, which poses the problem that it cannot be accommodated within the specified dimensions.

[0006] The present disclosure has been made to solve the problems described above, and aims to provide a light distribution control lens and a lighting device equipped with a light distribution control lens that can obtain a required luminous flux while using only one lens and keeping the lens diameter within a specified dimension. [Means for solving the problem]

[0007] A light distribution control lens according to the present disclosure has an entrance surface through which light is incident and an exit surface from which light is emitted, and controls the distribution of light emitted by a light source, and has a main recess formed to be recessed from a bottom surface to an upper surface, the entrance surface is provided on the bottom surface side so as to face the light source, and the exit surface is provided above and to the sides of the main recess over a wider area than the main recess, and has a first surface which is provided on the upper surface and is a surface that slopes toward the light source as it progresses radially outward from a central axis of the light distribution control lens, a second surface which is provided on the upper surface radially outer than the first surface and is a surface that slopes away from the light source as it progresses radially outward, a third surface which is provided on the upper surface radially outer than the second surface and is a surface that slopes toward the light source as it progresses radially outward, and a fourth surface which is a torus-shaped curved surface provided on a side surface radially outer than the third surface.

[0008] Moreover, an illumination device according to the present disclosure includes the above-described light distribution control lens and the above-described light source. Effect of the Invention

[0009] According to the light distribution control lens and the lighting device including the light distribution control lens of the present disclosure, a step surface is formed by the second and third surfaces on the radially outer upper surface between the first and fourth surfaces of the emission surface of the light distribution control lens, and the radially outer upper surface is discontinuously shifted upward. As a result, the emission position of the radially outer upper surface of the emission surface of the lens shifts upward and can exceed the partition walls, so that even if there are partition walls on the outside of the lens, a decrease in the amount of light can be suppressed, and the required luminous flux can be obtained even if only one lens is used and the lens diameter is kept within a predetermined dimension. [Brief description of the drawings]

[0010] [Figure 1] 1 is an exploded perspective view of a lighting device according to a first embodiment. [Diagram 2] 4 is a cross-sectional view of the lighting device according to the first embodiment at the center of the lens in the direction along the X-axis. FIG. [Diagram 3] 5 is a cross-sectional view illustrating light of group A of the lighting device according to the first embodiment. FIG. [Figure 4] 5 is a cross-sectional view illustrating light of group B of the lighting device according to the first embodiment. FIG. [Diagram 5] 5 is a cross-sectional view illustrating light of group C of the lighting device according to the first embodiment. FIG. [Figure 6] 4 is a cross-sectional view showing the path of light reflected on an emission surface of the lighting device according to the first embodiment until it is extracted. FIG. [Figure 7] 4 is a cross-sectional view showing the path of light that is re-incident on the emission surface of the lighting device in accordance with Embodiment 1 until it is extracted. FIG. [Figure 8] 3 is a light distribution diagram of light extracted from a lens of the lighting device according to the first embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. In addition, the size relationships of the components in the drawings may differ from the actual ones.

[0012] Embodiment 1 Fig. 1 is an exploded perspective view of a lighting device 100 according to embodiment 1. As shown in Fig. 1, the lighting device 100 according to embodiment 1 includes a light source module 1, a light source holder 2, a lens 3, a lens holder 4, a housing 5, and a design cover 6. Hereinafter, the lens 3 may be referred to as a light distribution control lens.

[0013] FIG. 2 is a cross-sectional view of the lighting device 100 according to the first embodiment at the lens center in the direction along the X-axis. Here, in FIG. 2, a part of the housing 5 and the design cover 6 are omitted because they are not related to the operation function of the lens 3. The same applies to FIGS. 3 to 7 described later. As shown in FIG. 2, the light source module 1 includes a light source 1a and a light source module substrate 1b. The light source 1a has, for example, a disk shape and is provided at the center of the light source module substrate 1b. The light source 1a is, for example, an array of a plurality of surface-mounted LEDs, or an LED package in which a surface light source such as a COB (Chip On Board) is mounted on a circuit board. Note that one or more LED packages called CSP (Chip Scale Package) may be used as the light source 1a. The light source module substrate 1b is a printed circuit board on which a circuit for turning on the light source 1a is mounted, and is made of, for example, aluminum in consideration of heat dissipation.

[0014] The light source module 1 is fixed by being fitted into the light source holder 2, and is joined to an electrode (not shown) of the light source holder 2 so that power is supplied from the outside. The light source module 1 is connected to wiring (not shown) by the light source holder 2, and is held at a position maintaining a certain distance from the lens 3 via the lens holder 4. The light source holder 2 is disposed between the lens 3 and the light source module 1, and fixes the light source module 1 and the lens 3.

[0015] The lens 3 is made of transparent glass or the like, and is formed, for example, in a rotationally symmetric shape centered on a central axis CA. The lens 3 has an entrance surface 10 where light is incident and an exit surface 20 where light is emitted, and controls the light distribution of the light emitted by the light source 1a. The entrance surface 10 of the lens 3 is provided on the bottom surface 31 side so as to face the light source 1a. The lens 3 also has a main recess 41 formed so as to be recessed from the bottom surface 31 to the top surface 32 side, and a sub-recess 42 which is a ring-shaped groove recessed from the bottom surface 31 to the exit surface 20 side so as to surround the main recess 41. Here, the main recess 41 and the portion between the main recess 41 and the sub-recess 42 on the bottom surface 31 are the entrance surface 10 of the lens 3. The exit surface 20 of the lens 3 is provided above and to the side of the main recess 41 over a wider range than the main recess 41. The exit surface 20 of the lens 3 includes a first surface 51 provided on the upper surface 32 and inclined so as to approach the light source 1a as it moves radially outward from the central axis CA of the lens 3, a second surface 52 provided on the upper surface 32 radially outward from the first surface 51 and inclined so as to move away from the light source 1a as it moves radially outward, a third surface 53 provided on the upper surface 32 radially outward from the second surface 52 and inclined so as to approach the light source 1a as it moves radially outward, a fourth surface 54 provided on the side surface 33 radially outward from the third surface 53 and inclined so as to approach the light source 1a as it moves radially outward, a fifth surface 55 provided in the sub-recess 42 and inclined so as to increase in diameter as it moves from the light source 1a to the first surface 51 side, and a V-shaped sixth surface 56 provided in the sub-recess 42 outside the fifth surface 55. That is, the exit surface 20 of the lens 3 is provided on the upper surface 32, the side surface 33, and the sub-recess 42.

[0016] The lens holder 4 has a function of being fixed to the housing 5, and only the emission surface 20 of the lens 3 is exposed by attaching the design cover 6. The housing 5 covers the bottom surface 31 of the lens 3 fixed by the light source module 1 and the light source holder 2 and the side surface 33 extending along the central axis CA. As shown in FIG. 1, the top surface of the housing 5 is open, and the light emitted from the lens 3 is irradiated from the opening of the housing 5. A partition wall 5a is provided on the outside of the side surface 33 of the lens 3 in the housing 5. When the lighting device 100 according to the first embodiment is used as an emergency light in conjunction with a regular light source, the partition wall 5a functions as a partition wall between the regular light source. The partition wall 5a has a height approximately equal to that of the lens 3, and is formed, for example, in a cylindrical shape so as to surround the outer periphery of the lens 3. It is not necessary for the partition wall 5a to surround the entire periphery of the lens 3, and it may be provided only between the lens 3 and the regular light source on the outer side. According to the regulations, it is sufficient that a partition wall is provided only between the lens 3 and the regular light source. The design cover 6 covers the lens 3 except for the light exit surface 20 , and constitutes the design surface of the lighting device 100 .

[0017] FIG 3 is a cross-sectional view illustrating light of group A of the lighting device 100 according to embodiment 1. FIG 4 is a cross-sectional view illustrating light of group B of the lighting device 100 according to embodiment 1. FIG 5 is a cross-sectional view illustrating light of group C of the lighting device 100 according to embodiment 1. In FIGS. 3 to 5, the light emitted from the center of the light source 1a is indicated by an arrow. Also, light emitted in a direction of 0 to 40° with respect to the front direction of the light source 1a is group A, light emitted in a direction of 40 to 70° is group B, and light emitted in a direction of 70 to 80° is group C.

[0018] Below, the behavior of the emitted light from group A will be explained using Fig. 3, that from group B will be explained using Fig. 4, and that from group C will be explained using Fig. 5. In order to explain the lens function, the lens surface of lens 3 is divided, and the branching points are incident surface points IS1 to IS4 on the lens incident surface side and exit surface points OS1 to OS8 on the lens exit surface side. The divided lens surfaces are incident surfaces 311 to 314 on the incident surface side and exit surfaces 321 to 328 on the exit surface side.

[0019] [Behavior of synchrotron radiation from group A] As shown in FIG. 3, light incident on an incident surface 311 between the central axis CA of the lens 3 and an incident surface point IS1 is emitted in a direction substantially parallel to the front.

[0020] Light incident on the incident surface 312 between the incident surface points IS1 and IS2 is emitted from the approximately horizontal exit surface 321 between the central axis CA of the lens 3 and the exit surface point OS1, traveling in a direction away from the central axis CA of the lens 3, and is emitted at a wider angle with respect to the Z axis on the exit surface 321 the further away from the central axis CA of the lens 3.

[0021] [Behavior of synchrotron radiation from group B] 4, incident surface 313 between incident surface point IS2 and incident surface point IS3 is composed of an extension of incident surface 312 and a surface closer to a vertical surface than that. Light incident on incident surface 313 from the extension of incident surface 312 is emitted from exit surface 321. On the other hand, light incident on incident surface 313 from a surface closer to a vertical surface is emitted from exit surface 323 between exit surface point OS2 and exit surface point OS3. That is, incident surface 313 largely changes the surface angle to prevent light from entering exit surface 322 sandwiched between exit surface point OS1 and exit surface point OS2.

[0022] The role of exit surface 322 is to bring the position of exit surface 323 in the Z direction closer to the height of partition wall 5a so that the light extracted from exit surface 323 is not blocked by partition wall 5a. For this reason, the surface has a step like a Fresnel lens, but the edge shape like a Fresnel lens is not sharp, in order to block as little light emitted from exit surface 321 as possible.

[0023] Even if exit surfaces 322 to 323 are gently stepped surfaces without sharp edges as in this shape, some light will still be taken in by exit surface 322, but the corresponding shape is exit surfaces 324 to 326 sandwiched between exit surface points OS3 to OS6. This will be described later. The light of group B is characterized by being extracted at a wider angle with respect to the Z axis than the light of group A.

[0024] [Behavior of synchrotron radiation from group C] 5, incident surface 314 between incident surface point IS3 and incident surface point IS4 has an inclination angle closer to the horizontal plane than incident surface 312, and the incident light reaches exit surface 328 between exit surface point OS7 and exit surface point OS8, where most of the light is totally reflected and emitted from the central axis CA side of exit surface 321. The emission direction of the light emitted from the central axis CA side of exit surface 321 is the exact opposite direction to the original direction in which the light was emitted from light source 1a (the direction in which the light entered incident surface 314).

[0025] Since the angle of incidence of light incident from incident surface 314 close to incident surface point IS4 is slightly smaller than the angle of incidence that results in the total reflection condition, there is a certain probability that some light will be transmitted through exit surface 328 (according to Fresnel's law, the transmittance from the interface and the reflectance at the interface are physically determined by the lens refractive index and the angle of incidence at the lens interface). The structures that regenerate such light are exit surface 326 sandwiched between exit surface point OS5 and exit surface point OS6, and approximately V-shaped exit surface 327 sandwiched between exit surface point OS6 and exit surface point OS7.

[0026] Light that has passed through exit surface 328 and is incident on exit surface 326 is emitted from exit surface 323 without changing its traveling direction. In addition, light that has passed through exit surface 328 and is incident on exit surface 327 is also made to re-enter from exit surface 327 and is emitted from exit surface 323.

[0027] Fig. 6 is a cross-sectional view showing the path of light reflected on exit surface 20 of lighting device 100 according to embodiment 1 until it is extracted. Fig. 7 is a cross-sectional view showing the path of light re-entering exit surface 20 of lighting device 100 according to embodiment 1 until it is extracted. Next, the functions of exit surfaces 324 to 326 will be described with reference to Figs. 6 and 7.

[0028] 6 is a cross-sectional view for explaining the function of regenerating a portion of light reflected by exit surface 321 with respect to light of group A. Since the light emitted from exit surface 321 is set to have a wide angle with respect to the Z axis, the angle of incidence on exit surface 321 is close to the critical angle, and therefore the probability of reflected light occurring at exit surface 321 is high.

[0029] 6 indicates the trajectory of light reflected by such exit surface 321. The light reflected by exit surface 321 is totally reflected by exit surface 326, then totally reflected by exit surface 325, and is emitted from exit surface 323.

[0030] 7 is a cross-sectional view for explaining the function of regenerating a portion of light reflected by exit surface 321 with respect to light of group B. A portion of the light emitted from exit surface 322 is incident on exit surface 322 again. This light is totally reflected by exit surfaces 323, 324, 325, and 326, and is emitted from exit surface 321.

[0031] In this way, exit surfaces 324 to 326 serve to deflect the light deflected toward light source module 1 toward exit surface 20 of lens 3 again and extract it.

[0032] In addition, exit surface 321 corresponds to the first surface 51, exit surface 322 corresponds to the second surface 52, exit surface 323 corresponds to the third surface 53, exit surface 324 corresponds to the fourth surface 54, exit surface 328 corresponds to the fifth surface 55, and exit surface 327 corresponds to the sixth surface 56.

[0033] FIG. 8 is a light distribution diagram of the light extracted from the lens 3 of the lighting device 100 according to the first embodiment. The horizontal axis of FIG. 8 indicates the angle (°) of the light traveling direction, and the front direction of the lens 3 (arrow Z direction in FIG. 2) is set to 0°. The vertical axis of FIG. 8 indicates luminous intensity (au). Here, luminous intensity is a physical quantity that relatively indicates the brightness of the light irradiated in each angular direction, and is expressed in arbitrary units. In addition, in FIG. 8, the light of group A is indicated by a solid line, the light of group B is indicated by a thin solid line, the light of group C is indicated by a dotted line, the light distribution of the entire lens 3 obtained by adding A to C is indicated by a thick solid line, and the target light distribution is indicated by a dashed line. As shown in FIG. 8, it can be seen that the light distribution of the entire lens 3 (thick solid line) exceeds the target light distribution (dashed line).

[0034] In the first embodiment, the diameter of the light source 1a is 6.7 mm, while the diameter of the lens 3 is 32.4 mm. The ratio of the diameter of the lens 3 to the diameter of the light source 1a is 4.83. The distance from the central axis CA of the lens 3 to the partition wall 5a is 21 mm, and the ratio of the distance from the central axis CA of the lens 3 to the partition wall 5a to the radius of the lens 3 (the diameter of the lens 3 / 2) is 1.3.

[0035] The total height of lens 3 is 9.3 mm, and all light emission positions are designed to be from surfaces with a height of 8.1 mm or more. In other words, the structure is such that light is extracted from a height of 87% or more of the height of lens 3. With this structure, approximately 90% of the light source luminous flux is extracted.

[0036] Incidentally, in Patent Document 1, the total light source width in the X direction is 4.6 mm, the lens diameter is 38 mm, and the ratio of the lens diameter to the light source diameter is 8.26. In other words, when the ratio of the lens diameter to the light source diameter is smaller than 8.26, a desired light distribution can be obtained by applying the shape of the first embodiment.

[0037] As described above, the light distribution control lens according to the first embodiment has an entrance surface 10 where light is incident and an exit surface 20 where light is emitted, and is a light distribution control lens that controls the distribution of light emitted by light source 1a, and has main recess 41 formed so as to be recessed from bottom surface 31 toward top surface 32, and entrance surface 10 is provided on the bottom surface 31 side so as to face light source 1a, and exit surface 20 is provided above and to the side of main recess 41 over a wider range than main recess 41, and is provided on top surface 32 and extends radially outward from central axis CA of the light distribution control lens. The light source 31 has a first surface 51 which is a surface that slopes toward the light source 1a as it moves radially outward, a second surface 52 which is provided on the upper surface 32 radially outer than the first surface 51 and which slopes away from the light source 1a as it moves radially outward, a third surface 53 which is provided on the upper surface 32 radially outer than the second surface 52 and which slopes toward the light source 1a as it moves radially outward, and a fourth surface 54 which is a torus-shaped curved surface provided on the side surface 33 radially outer than the third surface 53.

[0038] According to the light distribution control lens of embodiment 1, a step surface is formed (by changing the tilt direction) on the radially outer upper surface 32 between the first surface 51 and the fourth surface 54 of the emission surface 20 of the light distribution control lens by the second surface 52 and the third surface 53, and the radially outer upper surface 32 is discontinuously shifted upward. For this reason, the emission position of the radially outer upper surface 32 of the emission surface 20 of the light distribution control lens shifts upward and can exceed the partition wall 5a, so that even if the partition wall 5a is present on the outside of the light distribution control lens, a decrease in the amount of light can be suppressed, and the required luminous flux can be obtained even if only one lens is used and the lens diameter is kept within a predetermined dimension.

[0039] Moreover, the light distribution control lens according to embodiment 1 emits light in directions of 0 to 40° with respect to the front direction of light source 1a, and the light reflected by first surface 51 is totally reflected and deflected by fourth surface 54, and is extracted from third surface 53.

[0040] According to the light distribution control lens according to the first embodiment, light incident from the emission surface 20 can be deflected by total reflection and emitted again.

[0041] Moreover, in the light distribution control lens of embodiment 1, light is emitted in a direction of 40 to 70° with respect to the front direction of light source 1a, and light that has transmitted through first surface 51 is re-entered from third surface 53, totally reflected and deflected by fourth surface 54, and extracted from first surface 51.

[0042] According to the light distribution control lens of embodiment 1, the light totally reflected by the emission surface 20 can be totally reflected and deflected by the fourth surface 54, and can be emitted again.

[0043] Moreover, the light distribution control lens according to embodiment 1 has sub-concave 42 which is a ring-shaped groove recessed from bottom surface 31 towards exit surface 20 so as to surround main concave 41, and exit surface 20 is provided in sub-concave 42 and has fifth surface 55 which is a slope whose diameter increases as it progresses from light source 1a towards first surface 51, and light which is emitted in a direction of 70 to 80° with respect to the front direction of light source 1a and reaches fifth surface 55 is reflected and extracted from the central axis CA side of first surface 51.

[0044] According to the light distribution control lens of embodiment 1, light emitted in a direction of 70 to 80° with respect to the front direction of light source 1a as the reference can be reflected by fifth surface 55 and extracted from the center of emission surface 20 without being blocked by partition wall 5a.

[0045] Moreover, in the light distribution control lens according to embodiment 1, exit surface 20 has a V-shaped sixth surface 56 provided in sub-recess 42 outside fifth surface 55, and the light is emitted in a direction at an angle of 70 to 80° with respect to the front direction of light source 1a as the reference. The light transmitted through fifth surface 55 is made to re-enter from sixth surface 56 and is extracted from third surface 53.

[0046] According to the light distribution control lens of embodiment 1, light is emitted in a direction of 70 to 80° with respect to the front direction of light source 1a, and light that has transmitted through fifth surface 55 is made to re-enter through sixth surface 56, and can be extracted from exit surface 20 without being blocked by partition wall 5a.

[0047] Moreover, the lighting device 100 according to the first embodiment includes the above-mentioned light distribution control lens and the above-mentioned light source 1a.

[0048] According to the lighting device 100 according to the first embodiment, it is possible to obtain the same effects as those of the above-mentioned light distribution control lens. [Explanation of symbols]

[0049] 1 light source module, 1a light source, 1b light source module board, 2 light source holder, 3 lens, 4 lens holder, 5 housing, 5a partition wall, 6 design cover, 10 incident surface, 20 exit surface, 31 bottom surface, 32 top surface, 33 side surface, 41 main recess, 42 sub-recess, 51 first surface, 52 second surface, 53 third surface, 54 fourth surface, 55 fifth surface, 56 sixth surface, 100 lighting device, 311-314 incident surfaces, 321-328 exit surfaces, CA central axis, IS1-IS4 incident surface points, OS1-OS8 exit surface points.

Claims

1. A light distribution control lens having an incident surface into which light is incident and an exit surface from which light is exited, the light distribution control lens controlling the light distribution of light emitted from a light source, A main recess is formed so as to be recessed from a bottom surface to an upper surface side, The light incidence surface is provided on the bottom surface side so as to face the light source, The exit surface is A recess is provided above and to the side of the main recess over a wider area than the main recess, a first surface that is provided on an upper surface and is a surface that is inclined so as to approach the light source as it moves radially outward from a central axis of the light distribution control lens; A second surface is provided on an upper surface radially outward from the first surface, and is a surface that inclines so as to move away from the light source as it moves radially outward; a third surface that is provided on an upper surface radially outward of the second surface and is inclined so as to approach the light source as it moves radially outward; and a fourth surface that is a torus-shaped curved surface provided on a side surface radially outward of the third surface. Light distribution control lens.

2. The light is emitted in a direction of 0 to 40 degrees from the front direction of the light source, and is reflected by the first surface, and is deflected by the fourth surface and extracted from the third surface. The light distribution control lens according to claim 1 .

3. The light is emitted in a direction of 40 to 70 degrees from the front direction of the light source, and the light transmitted through the first surface is made to re-enter through the third surface, is totally reflected by the fourth surface, and is deflected, and is taken out from the first surface. The light distribution control lens according to claim 1 .

4. a sub-recess which is a ring-shaped groove recessed from the bottom surface toward the light exit surface so as to surround the main recess, The exit surface is a fifth surface that is provided in the sub recess and is an inclined surface whose diameter increases as the inclination advances from the light source toward the first surface; The light is emitted in a direction of 70 to 80 degrees from the front direction of the light source and reaches the fifth surface, and is reflected and extracted from the central axis side of the first surface. The light distribution control lens according to claim 1 .

5. The exit surface is a V-shaped sixth surface provided in the sub-recess outside the fifth surface; The light is emitted in a direction of 70 to 80 degrees from the front direction of the light source, and the light transmitted through the fifth surface is made to re-enter through the sixth surface and is extracted through the third surface. The light distribution control lens according to claim 4 .

6. The light distribution control lens according to any one of claims 1 to 5, The light source and Lighting equipment.

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