JP6106872B2 - Bulk-type lens, light emitter using the same, and illumination device - Google Patents

Description

  The present invention relates to a bulk-type lens, a light emitter using the same, and an illumination device, and more specifically, for efficiently collecting and emitting light emitted from a flat light emitter that emits light in a large area such as a high-power LED. The present invention relates to a bulk lens, a light emitter that combines a bulk lens and a large-area planar light emitter, and an illumination device using the light emitter.

  LEDs have been used in many fields such as home lighting fixtures, street lamps, and spot lighting devices because of their high luminous efficiency, but they have lower brightness and higher prices than fluorescent lamps and mercury lamps. Technologies have been developed that efficiently concentrate and illuminate only the necessary parts.

  Patent Documents 1 and 2 disclose a bulk type lens that efficiently collects light emitted from an LED or the like. The bulk type lens is suitable as a street lamp or a spot lighting device because it efficiently collects light from a light source such as an LED.

  FIG. 13 is a cross-sectional view showing the structure of a conventional bulk lens 100. As shown in FIG. 13, a conventional bulk lens 100 (see Patent Document 1) is an optical medium including a top portion 102 and a concave portion 105 that houses a light source 107 such as an LED inside the lens. The concave portion 105 includes a first curved surface 105a (light incident portion) and an inner peripheral portion 105b of the ceiling portion. The top portion 102 has an emission surface composed of a second curved surface 102a that emits light incident from the first curved surface 105a in the optical axis direction. The inner peripheral portion 105 b of the concave portion 105 functions as an incident surface for the stray light component of the light source 107.

  When a known bulk-type lens 100 is mounted on a conventional lens-shaped resin-coated LED 107 in Patent Documents 1 and 2, etc., a first curved surface 105a (concave ceiling), a second curved surface 102a (concave ceiling), an optical transmission path By design such as length (distance on the optical axis between the first curved surface 105a and the second curved surface 102a), the 1/2 beam angle is 7 to 40 degrees and the light utilization efficiency is about 90%. Characteristics can be realized.

FIG. 14 is a diagram showing an example of the light emission characteristics of a light emitter in which a conventional bulk lens 110 and a lens-shaped resin-coated LED 107 are combined. The bulk lens 110 further includes a side wall portion 104 between the top portion 102 and the bottom portion 103.
The curvature radius of the second curved surface 102a of the bulk lens 110 is 8.25 mm, the curvature radius of the first curved surface 105a is 5 mm, and the length on the optical axis between the first curved surface 105a and the second curved surface 102a (guide). A lens-shaped resin-coated LED 107 is combined with an acrylic resin (n = 1.49) bulk lens 110 having an optical path length of 10.6 mm and an outer diameter of 15 mm.

  The light emission relative intensity of the lens-shaped LED 107 is as follows: emission angle 0 degrees: 1, ± 20 degrees: 0.9, ± 40 degrees: 0.55, ± 60 degrees: 0.09, ± 70 degrees: 0.05 Yes, when the bulk type lens 110 is mounted, the light emission relative intensity is as follows: emission angle 0 degree: 2.7, ± 20 degrees: 1.35, ± 40 degrees: 0.09, ± 60 degrees: 0.05, ± 70 degrees: 0.03. The 1/2 beam angle was about 85 degrees for the LED alone, but was about 40 degrees when the bulk lens 110 was attached. The light beam within a ½ beam angle when the bulk lens 110 is attached has a very excellent light condensing property that condenses about 90% of the light beam of the LED 107 alone.

JP 2001-44515 A JP 2002-221658 A

  The LED 107 has better luminous efficiency than fluorescent lamps and mercury lamps, but the output is still small, and development and commercialization of high-power LEDs are being promoted. In recent high-power LEDs, many LED chips are arranged on a single substrate, and the diameter of the light emitting surface is 5 mm to 15 mm or larger, and there is no lens-like resin coat, and surface emission is almost uniform. However, the light emission angle is very wide. When the conventional bulk type lenses 100 and 110 are attached to such a high output LED, the light emission angle is not so small and the light utilization efficiency is also lowered.

  In the LED 107 without the lens-like resin coat, the emitted light intensity is substantially proportional to the sin of the emission angle, and the relative light emission intensity at the emission angles of 0 degrees, 20 degrees, 40 degrees, 60 degrees, and 70 degrees is about 1, 0. .94, 0.77, 0.5, and 0.34 have a wide radiation angle and a large deviation from the lens optical axis. The light beam greatly deviating from the optical axis of the bulk lens 110 is considered to be totally reflected by the lens outer wall or radiated in a direction deviating greatly from the optical axis direction, thereby reducing the light utilization efficiency.

  In the conventional bulk type lenses 100 and 110 having a diameter of about 15 mm, when the diameter of the light emitting surface is increased, the light loss from the optical axis of the light emitting point is 2.5 mm, and the light loss due to total reflection is caused even when the diameter of the light source is 5 mm. The light emission angle becomes larger.

  Even in the case of a light source in which small LED elements 107 are simply arranged on a plane in order to increase the size, if the light is received in one large bulk type lens 100, 110, the emitted light from the LED at a portion away from the optical axis is emitted from the lens. There is a problem that the light is totally reflected on the radiation surface to be lost, and is emitted in a direction away from the optical axis.

In view of the above problems, the present invention provides a light emitter that combines a bulk type lens and a large area planar light emitter for efficiently condensing and radiating light emitted from a planar light emitter that emits light in a large area such as a large output LED. The first object is to provide the second object, and the second object is to provide an illumination device using the light emitter.

  The inventors of the present invention have provided that the angle of the lens top light exit surface is not totally reflected with respect to the radiation angle that is desired to be effectively collected from the outermost light emitting portion of the light source that emits light in a large area such as an LED. In addition, the angle is set in the direction that matches the desired light directivity. Specifically, the bulk type lens is designed by the conventional method, and the light locus is changed at the position farthest from the optical axis of the light emitting surface. And gradually increase the curvature of the lens exit surface or the angle between the lens exit surface and the optical axis from the light emission angle close to the total reflection condition on the lens light exit surface, or the curvature of the lens light exit surface. In order to prevent infinite (conical) and to prevent total reflection on the outer wall that is nearly vertical, the light at the radiation angle that is desired to be collected effectively should hit the lens top light exit surface, not the side wall. To improve the light collection efficiency of planar LEDs Found to be able to above has led to the present invention.

To achieve the first object, the light emitter of the present invention, a top, a bottom, a side wall portion, and a recess consisting of the ceiling portion and an inner peripheral portion formed toward said top from the bottom, consisting of A bulk-type lens and an LED housed in the concave portion with a gap from the concave portion, the light emitting surface of the LED having a diameter of 1/6 or more of the diameter of the side wall portion , Consists of a lens surface , the top part is composed of a central part and a connection part connected from the central part to the side wall part, the top part constitutes a second lens surface, and the connection part is in the same direction as the central part It has a curved surface or conical surface with a curvature radius different from that of the central portion that is inclined, and the light emission angle is set to be larger than that of the central portion, and the emitted light of the LED is directed to the first lens surface of the ceiling portion. Incident light is radiated to the outside from the second lens surface at the top, which is composed of the central part and the connection part. The light emitted from the LED located on the outermost side from the optical axis of the lens reaches the connecting portion of the second lens surface from the first lens surface, and the light that reaches the connecting portion is not totally reflected. Radiated at an angle .

In the above configuration, the light incident surface of the ceiling is preferably a flat surface or a curved surface. The connecting portion is preferably formed by a straight line formed from a tangent line at the end of the central portion, and has a conical shape as a whole .
The surface of the side wall is preferably coated with a rough surface or a light scatterer.
The planar LED may be disposed in the concave portion of the bulk lens via a gas or fluid having a refractive index smaller than that of the bulk lens.

In order to achieve the second object, an illumination device of the present invention includes at least one light emitter described in any of the above and a power supply unit connected to the light emitter.

  According to the present invention, it is possible to effectively collect light emitted from a light source that emits light in a large area, and to realize a bulk lens, a light emitter, and an illumination device with a narrow light irradiation angle and with little loss.

It is sectional drawing which shows the structure of the bulk type lens which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the light-emitting body using the bulk type lens of this invention. It is a figure which shows the light emission characteristic of the bulk type lens which concerns on 1st Embodiment. It is a figure which shows the locus | trajectory of the light ray on the optical axis of the bulk type lens of a comparative example. It is a figure which shows the locus | trajectory of the light ray radiated | emitted from the light source surface 5 mm away from the optical axis of the bulk type lens of the comparative example. It is a figure which shows the locus | trajectory of the light ray radiated | emitted from the light source surface 10 mm away from the optical axis of the bulk type lens of the comparative example. It is sectional drawing which shows the structure of the modification of the light-emitting body using the bulk type lens of this invention. It is sectional drawing which shows the structure of the bulk type lens which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the light-emitting body using the bulk type lens of this invention. It is a figure which shows the light emission characteristic of the bulk type lens which concerns on 2nd Embodiment. It is sectional drawing which shows the structure of the modification of the light-emitting body using the bulk type lens of this invention. It is a block diagram which shows typically the illuminating device which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the conventional bulk type lens. It is a figure which shows the light emission characteristic of the light-emitting body which combined the LED by which the conventional bulk type lens and resin-coated LED were carried out.

Embodiments of the present invention will be specifically described below with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view showing a configuration of a bulk type lens 1 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a configuration of a light emitter 10 using the bulk type lens 1 of the present invention. It is.
As shown in FIG. 1, the bulk lens 1 of the present invention includes a top portion 2, a bottom portion 3, a side wall portion 4, a ceiling portion 5a formed from the bottom portion 3 toward the top portion 2, and an inner peripheral portion 5b. And a recess 5. The bulk lens 1 is made of an optical medium. The concave portion 5 serves as a housing portion for the light source 7 composed of an LED or the like shown in FIG.

As shown in FIG. 2, the light emitter 10 using the bulk lens 1 of the present invention accommodates a light source 7 made of an LED or the like in the concave portion 5 of the bulk lens 1. The concave portion 5 is accommodated with air 8 having a refractive index different from that of the bulk lens 1, a fluid other than air, or a fluid 9. The refractive index (n ₁ ) of the optical medium that is the material of the bulk lens 1 is larger than the refractive index (n ₀ ) of the fluid such as air 8. The LED 7a is a planar LED, and a plurality of LED chips are arranged on a substrate. In FIG. 2, the planar LED 7 a is further mounted on the heat sink 12. The bottom 3 of the bulk lens 1 is fixed to the heat sink 12 with an adhesive or the like. The shape of the planar LED 7a is a circle, an ellipse, a quadrangle, or the like. The area of the planar LED 7a is, for example, 5 mm to 30 mm in diameter. In the following description, it is assumed that the planar LED 7a has a diameter of 20 mm and is housed in the concave portion 5 of the bulk lens 1 through the air 8.

  The ceiling part 5a of the recess 5 serves as a first curved surface and serves as a light incident part of the flat LED 7a. Since air 8 having a refractive index lower than that of the bulk lens 1 is inserted between the ceiling portion 5a of the concave portion 5 and the flat LED 7a, the light is emitted from the flat LED 7a even if the first curved surface is flat. The refracted light is refracted and condensed in the optical axis direction, and acts as a first lens surface. The first curved surface (light incident surface) of the ceiling portion 5a of the recess 5 may be a flat surface or a curved surface. In order to converge the light emitted from the planar LED 7a in the optical axis direction, the curvature may be increased. If the light incident surface of the ceiling 5a of the recess 5 is a flat surface, the curvature becomes infinite (∞), so that the light condensing property in the optical axis direction can be enhanced. Conversely, if the light incident surface of the ceiling portion 5a of the recess 5 is a curved surface, the light condensing property can be lowered.

  The side wall portion 4 and the bottom portion 3 act as reflecting surfaces, and transmit light (stray light) in the direction of the side wall portion 4 and the bottom portion 3 to the top portion 2, that is, deviate from the inner optical axis of the light emitted from the planar LED 7a. Therefore, the side wall part 4 and the bottom part 3 have a function of collecting stray light on the top part 2.

The top portion 2 includes a central portion 2a on the optical axis side and a connecting portion 2b connected to the side wall portion 4 from the central portion 2a. The central part 2a is a second curved surface. In the bulk type lens 1 of FIG. 1, the central portion 2a is a spherical surface or an elliptical spherical surface. As shown in FIG. 1, the connecting portion 2 b is a curved surface that is a straight line that is in contact with the curved surface of the central portion 2 a at an angle θ with respect to the optical axis, and has a conical shape with a vertex on the optical axis.
The central portion 2 a and the connecting portion 2 b converge and emit light incident from the first curved surface and a light beam from the light source 7 reflected from the side wall portion 4 and the bottom portion 3 in the optical axis direction of the bulk lens 1. That is, since the outside of the bulk lens 1 is air 8, the central portion 2a and the connecting portion 2b of the top portion 2 act as a second lens surface.

  The lens exit surface close to the optical axis of the top portion 2 of the bulk lens 1, that is, the cross section of the central portion 2 a is substantially circular or elliptical, and is generally spherical. In the top portion 2 of the bulk lens 1, that is, the connection portion 2b, the cross section of the lens exit surface that is separated from the optical axis by a predetermined distance or more is a straight line formed from the tangent line of the circular or elliptical end, and is generally a cone Is. The end portion of the top portion 2 is a boundary portion where the central portion 2a and the connecting portion 2b are connected.

  In the bulk type lens 1 of the present invention, a case will be described in which a light source 7 including, for example, a planar LED 7a having a diameter of 5 mm or more is installed around the optical axis inside the bulk type lens 1. Light of a predetermined irradiation angle that is desired to be effectively collected forward by light emitted from the outermost position from the optical axis of the light source 7 composed of the planar LED 7a is incident on the inside of the lens from the light incident surface of the ceiling portion 5a of the recess 5. However, it reaches the spherical and conical lens exit surface. The angle of the lens exit surface is such that the light reaching the lens exit surface is not totally reflected by the lens exit surface.

  In the first embodiment, the light source 7 having a circular light emitting surface is assumed. However, in the case of the light source 7 having a rectangular or elliptical light emitting surface, the lens cross section perpendicular to the optical axis may be elliptical.

  In the case of an elliptical lens, the cross-sectional shape of the lens exit surface may be designed in the same manner. The optical axis cross section of the lens, that is, the central portion 2a is elliptical, and the connecting portion 2b is elliptical near the optical axis. Make a straight line that is a tangent to the boundary.

  In addition, even if the optical axis cross-sectional shape of the lens exit surface near the optical axis is not perfectly circular, if the angle with the optical axis of the peripheral lens exit surface is small, all the emitted light from the light emitting surface off the optical axis will be emitted. Since the light is reflected, the cross section of the peripheral portion of the lens exit surface is made straight, the angle with the optical axis is increased, total reflection can be prevented, and the light collection rate can be increased.

  Since the bulk type lens 1 has a lens action and an optical transmission function for connecting the incident surface (the ceiling portion 5a of the concave portion 5) and the emission surface (the top portion 2), the material of the optical medium used for the bulk type lens 1 is an optical material. It is a material that is transparent with respect to the wavelength. As the optical medium, a transparent resin such as an acrylic resin, that is, various plastic materials such as a transparent plastic material, quartz glass, soda-lime glass, borosilicate glass, and lead glass can be used. Alternatively, a crystalline material such as zinc oxide (ZnO), zinc sulfide (ZnS), or silicon carbide (SiC) may be used. Further, a material such as a transparent rubber having flexibility, flexibility and elasticity may be used.

(Light emission characteristics of bulk lens)
The light emission characteristics of the bulk lens 1 will be described.
The bulk type lens 1 in FIG. 1 was made of an acrylic resin. The dimension of each part of the bulk type lens 1 is shown below.
Curvature radius of first curved surface 5a: ∞ (plane)
Central portion 2a (second curved surface) of the top portion 2: a portion having a curvature radius of 30 mm and an angle θ of 46 degrees or less (see FIG. 1)
Connection portion 2b of the top portion 2: a conical shape that becomes a tangent at an angle θ46 ° of the second curved surface (see FIG. 1)
Light guide length: 55mm
Side wall 4 diameter: 66 mm
Dimension of flat LED 7a: Diameter 20mm
Distance between flat LED 7a and first curved surface 5a: about 2 mm

  The light emission of the light emitted from the planar LED 7a (emission angle 0, ± 20 degrees, ± 40 degrees, ± 60 degrees, ± 70 degrees) was estimated. As the position of the light emitting surface 7b of the planar LED 7a deviates from the optical axis, it is totally reflected on the lens emitting surface, and the emitted light deviates from the optical axis.

  FIG. 3 is a diagram showing the light emission characteristics of the bulk lens 1 according to the first embodiment. As shown in FIG. 3, the light emitted from the light emitting surface 7b 10 mm from the optical axis at the outer side of 20 °, 40 °, 60 °, and 70 ° is about 13 °, 26 °, 36 °, and 39 ° from the lens incident surface. Incident at. Since the incident angle for total reflection on the lens exit surface is about 42 degrees, the angles with the optical axis of the lens surface that become the total reflection critical angle are about 35 degrees, 22 degrees, 12 degrees, and 9 degrees, respectively.

  Light emitted 20 degrees outward from the optical axis is incident at approximately 13 degrees from the lens incident surface, and is emitted at approximately 8 degrees in the direction opposite to the optical axis at a central angle of approximately 46 degrees on the lens exit surface (trajectory of light emission). 16).

  As shown in FIG. 5 and the like of a comparative example to be described later, when the emission angle from the LED becomes larger, total reflection is performed on the lens emission surface, so that the spherical center angle θ of the lens emission surface is about 46 degrees as shown in FIG. If the above lens surface angle is conical with an angle of 44 degrees with respect to the optical axis (tangential line with a spherical central angle of 46 degrees), the incident angle is smaller than the total reflection critical angle even for light having a larger emission angle. Therefore, total reflection can be prevented.

  As shown in FIG. 3, the light emitted at 40 degrees, 60 degrees, and 70 degrees outside the optical axis is incident at about 26 degrees, 36 degrees, and 39 degrees from the lens incident surface. The incident angles at the conical surface 2b of 44 degrees on the optical axis are about 20 degrees, 10 degrees, and 7 degrees, respectively, which are less than the critical angle of total reflection, and the refraction angles are about 31 degrees, 16 degrees, and 10 degrees, respectively. The light emission angles with respect to the optical axis are about 15 degrees, 30 degrees, and 36 degrees, respectively.

  The light emitted from the light emitting surface 7b 10 mm from the optical axis to the outside 70 degrees reaches the conical lens emitting surface 2b at a position 66 mm from the optical axis, and the diameter of the lens that effectively emits this light is as follows: It can be seen that 66 mm or more is required (see the light emission locus 17). In this embodiment, in order to reduce the lens diameter as much as possible, the lens diameter is 66 mm for effectively collecting the emitted light up to a radiation angle of 70 degrees where the LED emitted light intensity is about 34% of the optical axis.

  According to the bulk type lens 1 of the present invention, as shown in FIG. 3, the light from the planar LED 17a having the light emitting surface 7b having a diameter of 20 mm is not totally reflected by the lens emitting surface 2b, and a lens with little loss is obtained. .

(Comparative example)
Next, as a comparative example for the bulk lens 1 of the present invention, the light emission characteristics of a conventional bulk lens 120 will be described.
In order to reduce the effect of deviation from the optical axis when using a flat LED, the comparative bulk type lens 120 has a relatively larger aperture than the conventional bullet type LED bulk lens 110 (see FIG. 14). As a result, the light emission characteristics were examined.

The bulk type lens 120 of the comparative example was made of an acrylic resin. The dimensions of each part in the bulk type lens 120 of the comparative example are shown below (see FIG. 4).
Curvature radius of first curved surface 105a: ∞ (plane)
Curvature radius of second curved surface 102a: 30 mm
Light guide length: 55mm
Flat LED dimensions: 20mm diameter
Distance between planar LED and first curved surface 35: about 2 mm
Side wall 104 diameter: 60 mm

  4 to 6 show a comparative example of the bulk type lens 120. The locus of light rays from the light emitting surface 107a on the optical axis, the locus of light rays emitted from the light emitting surface 107a 5 mm away from the optical axis, and the optical axis, respectively. It is a figure which shows the locus | trajectory of the light ray radiated | emitted from the light emission surface 107a away from 10 mm. The figure shows the trajectory of light rays calculated by setting the emission angle of light emitted from the light emitting surface 107a of the flat LED 107 as 0, ± 20 degrees, ± 40 degrees, ± 60 degrees, and ± 70 degrees with respect to the optical axis. ing.

  As shown in FIG. 4, the locus 112 of the light beam emitted from the light emitting surface 107a on the optical axis of the lens is excellent in the light condensing property, but the light tends to radiate slightly inward in the light beam of 60 degrees or more. .

  As shown in FIG. 5, the trajectory 113 of the light beam emitted from the light emitting surface 107a that is 5 mm away from the lens optical axis is also bent vertically inward by the lens boundary, and at 60 degrees or more in the outward direction of the optical axis. The emitted light is totally reflected on the lens exit surface, and then emitted in a direction greatly deviating from the lens optical axis, and does not become light effective for illumination.

  As shown in FIG. 6, in the locus 114 of the light beam emitted from the light emitting surface 107a that is 10 mm away from the lens optical axis, the light emitted at an angle of 40 degrees or more outward from the optical axis is totally reflected by the lens output surface. The loss as lighting becomes larger.

  In the conventional bulk type lens 110 having a diameter of about 15 mm, the deviation of the light emission point from the lens optical axis is four times the above calculation, so the deviation of the light emission point from the optical axis is 2.5 mm, and the diameter of the light source Even when 5 mm, the light loss was large and the light emission angle was large.

  In order to increase the size of the illuminant, a light source in which small LED elements are simply arranged and mounted on a flat surface without using a flat LED was also examined. In this case as well, when housed in one conventional large bulk lens, the light emitted from the small LED at a portion away from the optical axis is totally reflected on the lens radiation surface and lost, and further away from the optical axis. Radiated in the direction.

As described above, in the bulk type lens 1 of the present invention, as shown in FIG. 3, the conical connecting portion 2b is further provided between the conventional top portion 2 and the side wall portion 4, and therefore, from the lens optical axis. Light of ± 70 degrees emitted from the light emitting surface 7b separated by 10 mm can be condensed and emitted at a radiation angle of about 70 degrees in the optical axis direction.
On the other hand, in the conventional bulk-type lens 120 shown in the comparative example, when the LED 107 that emits light in a large area is condensed by the conventional bulk-type lens 120, light having a large radiation angle from the light-emitting portion off the optical axis is emitted from the lens exit surface It can be seen that the loss is increased due to total reflection and the light emission angle is increased.

  In the first embodiment, the displacement from the lens optical axis of the light source 7 is 10 mm and the diameter of the light source 7 is 20 mm. However, the conventional bulk lens 110 having a diameter of about 15 mm has a light emitting surface light source of 5 mm in diameter. But the convergence was reduced. For this reason, in order to condense the light of the light source of the light emission surface of diameter 5mm effectively, the design similar to the bulk type lens 1 of 1st Embodiment is required.

  In the first embodiment, in order to make the incident angle of the LED 7a to the lens as close as possible to the optical axis direction, the first curved surface (light incident portion on the ceiling) 5a of the concave portion 5 is a flat surface. In order to realize this, a spherical surface may be used.

  When the first curved surface (ceiling light incident portion) 5a is a spherical surface, the incident angle to the lens is slightly smaller than that of a flat surface and the refraction angle is also slightly smaller. The arrival position of the emitted light of the LED 7a is further outward, the light emission angle is slightly larger, and the necessary lens diameter is also slightly larger.

  In the first embodiment, the peripheral portion 2b having a central angle θ equal to or larger than the central angle θ of the second curved surface (light emitting portion) 2a is conical, but in the case of the conical shape, the light emitting angle is as shown in FIG. When it becomes larger, the light emission angle becomes larger and the lens outer shape becomes larger.

(Modification of the first embodiment)
FIG. 7 is a cross-sectional view showing a configuration of a modification of the light emitter using the bulk lens 1 of the present invention. As shown in FIG. 7, the light emitter 20 using the bulk lens 1 of the present invention is different from the light emitter 10 using the bulk lens 1 of FIG. The flat LED 7a is interposed between the gap of the concave portion 5, that is, between the concave portion 5 and the flat LED 7a via a transparent resin or gel 22 having a refractive index smaller than that of the lens medium. It is a point that is arranged.

  When a transparent resin or gel 22 is inserted between the concave portion 5 of the bulk lens 1 and the planar LED 7a, the difference in refractive index between the bulk lens 1 and the gel 22 is reduced, so that the first curve serving as the incident surface is formed. The effect of refracting in the optical axis direction on the surface 5a is reduced. However, the reflection at the entrance surface to the bulk lens 1 becomes very small, and the heat generated by the planar LED 7a can be easily radiated by the bulk lens 1.

  When light irradiation with a narrow angle in the optical axis direction is not performed, it is better to arrange the planar LED 7a via a transparent resin or gel 22. For example, the silicone gel 22 is transparent and has excellent heat resistance and reliability.

(Second Embodiment)
FIG. 8 is a cross-sectional view showing a configuration of a bulk type lens 30 according to the second embodiment of the present invention, and FIG. 9 is a cross-sectional view showing a configuration of a light emitter 40 using the bulk type lens 30 of the present invention. is there.
The bulk type lens 30 shown in FIG. 8 is different from the bulk type lens 1 of FIG. 1 in that the connecting part 32b of the top part 32 is not a conical surface.

  Specifically, the connecting portion 32b of the bulk type lens 30 shown in FIG. 8 is a surface formed by a straight line formed by a tangent of a circular end portion of the cross section of the lens exit surface separated from the optical axis by a predetermined distance, that is, These straight lines gather together to form a surface formed between a conical surface A and a cylinder formed of a perpendicular tangent line B on a circular extension of the cross section. This cylinder is connected to the second curved surface. The connecting portion 32b is formed such that the angle of the lens exit surface with the optical axis gradually decreases as the lens exit surface moves away from the optical axis. The other configuration is the same as that of the bulk lens 1 of FIG.

  In the bulk type lens 30 shown in FIG. 8, when a large area planar light source 7 having a diameter of 5 mm or more is installed around the optical axis inside the bulk type lens 30, the light is emitted from the outermost position from the optical axis of the light source 7. The light having a predetermined radiation angle that is desired to be effectively collected forward by the incident light is incident on the inside of the lens from the light incident surface of the ceiling portion 35a of the recess 35 and reaches the lens exit surface. The light exiting from the lens is not totally reflected by the lens exit surface, and the lens exit surface angle is such that the exit light from the lens exits in a direction close to the optical axis.

(Light emission characteristics of bulk type lens according to the second embodiment)
The light emission characteristics of the bulk lens 30 will be described.
The bulk lens 30 was made of an acrylic resin. The dimensions of each part of the bulk lens 30 are shown below.
Curvature radius of first curved surface 35a: ∞ (plane)
Central portion 32a of the top portion 32 (second curved surface): a portion having a radius of curvature of 30 mm and an angle θ of 46 degrees or less. Connection portion 32b of the top portion 32: a conical shape in which the angle θ of the second curved surface is 46 degrees and a tangent line; A shape in which the angle with the optical axis gradually decreases from the extension line of the second curved surface toward the periphery. Light guide path length: 55 mm
Side wall 34 diameter: 63 mm
Dimension of flat LED 7a: Diameter 20mm
Distance between flat LED 7a and first curved surface 35a: about 2 mm

  FIG. 10 is a diagram illustrating the light emission characteristics of the bulk lens 30 according to the second embodiment. As shown in FIG. 10, light can be emitted from the connecting portion 32b of the lens exit surface at a central angle θ or more at the central portion that does not become the total reflection critical angle on the lens exit surface. By providing the connection portion 32b between the vertical tangent line B connected to the extension line of the second curved surface and the tangent line A at the end of the central portion 32a, the center angle θ can be set by adjusting the shape of the connection portion 32b. Can be gradually increased. As a result, total reflection caused by the conventional bulk lens 120 can be prevented, and the light emission angle can be made smaller.

For example, light emitted at 20 °, 40 °, 60 °, and 70 ° from the light emitting surface 7b 10 mm from the optical axis is incident at about 13 °, 26 °, 36 °, and 39 ° from the lens incident surface. If the angle of the lens exit surface with the optical axis is about 44 degrees, 38 degrees, 30 degrees, and 26 degrees, respectively, the incident angles on the lens exit surface are about 33 degrees, 26 degrees, 24 degrees, and 25 degrees, respectively, and total reflection The refraction angles are about 53 degrees, 42 degrees, 38 degrees, and 39 degrees, respectively.
The angles of the light emission angle and the optical axis are about -8 degrees (in the opposite direction to the optical axis, see the light emission locus 36 in FIG. 10), 10 degrees, 22 degrees, and 25 degrees (the light emission locus in FIG. 10). 37), and it can be seen that light emission is closer to the optical axis direction than in the case where the connecting portion 2b of the bulk lens 1 shown in FIG. 3 is conical.

  As shown in FIG. 10, according to the bulk lens 30 according to the second embodiment, the light condensing performance is improved and the necessary lens diameter can be reduced.

(Modification of the second embodiment)
FIG. 11 is a cross-sectional view showing a configuration of a modification of the light emitter using the bulk lens 30 of the present invention.
As shown in FIG. 11, the light emitter 45 using the bulk lens 30 is different from the light emitter 10 using the bulk lens 1 shown in FIG. The flat LED 7a is interposed between the gap of the concave portion 35, that is, between the concave portion 35 and the flat LED 7a via a transparent resin or gel 22 having a refractive index smaller than that of the optical medium. This is the point that was placed. Since the effect of disposing the planar LED 7a via the transparent resin or gel 22 is the same as that of the light emitter 10 using the bulk lens 1 of the modification of the first embodiment, the description is omitted.

  In the above description, the large-area planar light source 7 has been described as uniform surface light emission. The light source 7 has the same effect when a light source in which small LED elements are arranged on a plane is housed in the bulk type lenses 1 and 30 of this embodiment instead of the planar LED 7a. In this case, the radiated light from the small LED at a portion away from the optical axis is not totally reflected by the lens emission surface, and is not emitted in the direction away from the optical axis. The light source 7 for large area planar light emission includes a light source that is not uniform surface light emission such as small LED elements arranged on a plane.

The effects of the bulk type lenses 1 and 30 of the present invention and the modifications of each part will be described. In the following description, the bulk type lens 30 will be described, but the present invention can also be applied to the bulk type lens 1.
The inner peripheral portion 35b of the concave portion 35 of the bulk lens 30 and the side wall portion 34 forming the outer wall cannot be the main path of the LED radiation light that is effectively condensed. As a structure for positioning the LED 7a close, secondly, as a transparent body for extracting the light irregularly reflected inside the flat LED 7 or the bulk lens 30, and thirdly, the bulk lens 30 from the flat LED 7a. There is an effect as a heat conductor that releases the received heat to the substrate and the heat radiating plate 12.

  In the second embodiment, the inner peripheral portion 35b of the recess 35 and the side wall portion 34 of the lens are parallel to the optical axis. However, since the main light emission paths of the bulk lenses 1 and 30 pass from the ceiling 35a of the recess 35 to the lens exit surface of the top 32, the inner peripheral portion 35b of the recess 35 and the side wall 34 of the lens are In particular, it does not have to be parallel to the optical axis.

  The side wall 34 of the bulk lens 30 may be provided with a groove or a hole for fixing the bulk lens 30 and the planar LED 7a.

  In the bulk lens 30, when the inner peripheral portion 35b of the recess 35 and the outer wall 34 are substantially parallel to the optical axis, the bulk lens 30 can be easily manufactured. Furthermore, there is an advantage that the heat received by the bulk type lens 30 from the LED 7a can be effectively released to the heat radiating plate 12.

  In addition, when the side wall 34 of the bulk lens 30 is close to a cylinder, the light directly hitting the side wall 34 from the planar LED 7a is emitted at a very large angle or is totally reflected and becomes backscattered or lost. If the surface is roughened or coated with a paint containing titanium oxide powder or the like to scatter light, the light can be emitted more effectively forward.

  In the second embodiment, the bulk lenses 1 and 30 are made of a general acrylic resin. However, any material may be used as long as it is transparent. For example, polycarbonate is excellent in heat resistance, and glass is heat resistant. Also excellent in reliability.

(Third embodiment)
A lighting device 50 according to a third embodiment of the present invention will be described.
FIG. 12 is a block diagram schematically showing an illumination device 50 according to the third embodiment of the present invention. As shown in FIG. 12, the illumination device 50 includes at least one or more light emitters 10 described above and a power supply unit 52 connected to the light emitters 10. The illuminating device 50 may include a cover portion 54 made of resin or the like on the side where the light emitter 10 is irradiated with light, or on the side of the radiator plate 12.

Since the light emitter 10 of the present invention can effectively collect the light emitted from the large area LED light source 7 and can realize various radiation characteristics, the characteristics, installation positions, and installation angles of the plurality of light emitters 10 are adjusted. By doing so, it is possible to realize a wide range of illumination characteristics such as uniform wide range illumination and uniform illumination elongated along the road surface. The illuminating device 50 may be configured by further including a rear-view mirror 53 on the bottom 3 of the bulk type lens, similarly to the illuminating device using the conventional LED. As the rear mirror 53, various mirrors such as a mirror plate, a structure in which a metal thin film is coated on a metal or resin material by vapor deposition or plating can be used.
In addition to the structure of FIG. 2, the light emitter 10 may use the light emitter 20 shown in FIG. 7, the light emitter 40 shown in FIG. 9, and the light emitter 45 shown in FIG.

  The planar LED 7a is configured by further connecting units in which single LEDs are connected in series to each other in parallel. As the forward voltage of the planar LED 7a, for example, a product having a voltage of about 9.6V to 50V is commercially available. The power source unit 52 connected to the light emitter 10 may be any power source that can supply a voltage and a forward current corresponding to the forward voltage of the planar LED 7a. Such a power supply unit 52 uses a commercial power supply (100V to 200V) or a storage battery as a power supply.

  The lighting device 50 may further include a sensor 56. When the sensor 56 is an illuminance sensor that detects sunshine, a power control circuit 58 that drives the power source 52 with the illuminance sensor 56 may be provided. In this case, the illumination device 50 can be illuminated only at night.

  According to the lighting device 50 of the present invention, it is possible to efficiently collect the light of the high-power LED, and the light utilization efficiency is improved. Road lights, lamps, etc. can be realized.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and it goes without saying that these are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 20: Bulk type | mold lens 2, 32: Top part 2a, 32a: Center part 2b, 32b: Connection part 3, 33: Bottom part 4, 34: Side wall part 5, 35: Concave part 5a, 35a: Ceiling part 5b, 35b: Inner circumference 7: Light source 7a: Planar LED
7b: Light emitting surface 8: Air 9: Fluid 10, 20, 40, 45: Light emitter 12: Radiation plate 16, 17, 36, 37: Trace of light emission 22: Gel 50: Lighting device 52: Power supply unit 53: Rear mirror 54: cover 56: sensor 58: power control circuit

Claims (6)

A bulk type lens comprising a top portion, a bottom portion, a side wall portion, and a concave portion comprising a ceiling portion and an inner peripheral portion formed from the bottom portion toward the top portion;
An LED accommodated in the recess with a gap from the recess;
With
The diameter of the light emitting surface of the LED is 1/6 or more of the diameter of the side wall,
The ceiling portion constitutes a first lens surface ,
It said top is composed of a connecting portion from the center portion and the central portion being connected to said side wall, said top constitute the second lens surface,
The connecting portion has a curved surface or a conical surface with a curvature radius different from that of the central portion and continuously inclined in the same direction as the central portion, and a light emission angle is set larger than the central portion ,
The emitted light of the LED is incident on the first lens surface of the ceiling portion and is radiated to the outside from the second lens surface of the top portion constituted by the central portion and the connection portion,
The light emitted from the LED located on the outermost side from the optical axis of the bulk lens reaches the connection portion of the second lens surface from the first lens surface, and the light reaching the connection portion is totally reflected. A illuminant that emits at a lens exit surface angle that does not . The light-emitting body according to claim 1, wherein a light incident surface of the ceiling portion is a flat surface or a curved surface. The connecting portion is made by a straight line formed from the tangent of the edge portion of said central portion, a conical shape as a whole, the light-emitting body according to claim 1 or 2. The light emitting body according to any one of claims 1 to 3 , wherein a surface of the side wall portion is coated with a rough surface or a light scattering body . The light emitting body in which a planar LED is disposed in the concave portion of the bulk lens according to any one of claims 1 to 4 via a gas or fluid having a refractive index smaller than that of the bulk lens. At least one or more light emitting body according to any one of claims 1 to 5, a power supply unit connected to the emitters, consisting of the lighting device.