JP2015118818A - Lighting appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably illuminate a desired irradiation range.SOLUTION: A lighting appliance 1 comprises an LED 2 which substantially-radially emits light frontward with an optical axis Ax along a fore-and-aft direction as a center, and a light guide lens 3 arranged in front of the LED 2. The light guide lens 3 has: an incident face 31 which is arranged at a portion opposing the LED 2 out of a rear face, and formed into a substantially-semi spherical shape with a position of the LED 2 as a center; a conical protrusion 33 which is protrusively arranged frontward in front of the LED 2 out of a front face with a position on the optical axis Ax as a tip; a front optical face 34 which is arranged at a periphery of the protrusion 33 out of a front face, formed into a hyperboloid shape having a focus point F located in front of the optical axis Ax, and can emit light frontward while internally reflecting light from the incident face 31 to a rear oblique sideway; and a rear reflection face 32 which is arranged at a periphery of the incident face 31 out of a rear face, formed into a free curved face shape having the same focus point F as the front optical face 34, and internally reflects light which is internally reflected at the front optical face 34.

Description

  The present invention relates to a lamp, and more particularly, to a lamp that controls light distribution of light from an LED (light emitting diode) with a light guide lens.

  In recent years, many types of lamps for general lighting have been proposed and put into practical use using LEDs having excellent environmental performance as a light source. In such a lamp, in general, light from the LED is controlled and irradiated so as to have a desired light distribution by a light guide lens disposed in front of the LED.

  Specifically, for example, in the lamp described in Patent Document 1, as shown in FIG. 5, the LED is disposed opposite to the center of the rear surface of the light guide lens, and the light guide lens is formed in the center of the front surface. It has a V-shaped first reflecting surface and a parabolic second reflecting surface formed on the side thereof. Then, the light emitted forward from the LED and incident on the light guide lens is reflected sideways by the first reflecting surface and then reflected to the front while being converted into parallel light by the second reflecting surface, and forward from the emitting surface. Is being irradiated.

JP 2005-190669 A

  However, the lamp described in Patent Document 1 has a light distribution having a strong directivity to the front, and thus cannot perform light distribution control so as to illuminate a desired irradiation range. Therefore, when the lamp is applied to a lighting fixture, only the portion immediately below the lamp becomes extremely dazzling and the eyes become tired.

  This invention is made | formed in view of the said subject, and aims at provision of the lamp which can illuminate a desired irradiation range suitably.

In order to achieve the above object, the invention described in claim 1
An LED that has an optical axis along the front-rear direction and emits light substantially radially forward about the optical axis;
A light guide lens disposed in front of the LED and irradiating the light emitted from the LED forward while controlling the light distribution;
A lamp comprising:
The light guide lens is
The light guide lens is provided on a portion of the rear surface of the light guide lens facing the LED, and is formed in a substantially hemispherical shape centered on the position of the LED, and allows the light emitted from the LED to enter the light guide lens. An incident surface;
A conical protrusion projecting forward with the position on the optical axis at the front end of the LED on the front surface of the light guide lens; and
Light that is provided around the protrusion on the front surface of the light guide lens, is formed into a hyperboloid having a focal point located in front of the optical axis, and is incident on the light guide lens from the incident surface. A front optical surface that is capable of emitting light forward while internally reflecting diagonally to the rear side,
The light guide lens is provided around the entrance surface of the rear surface of the light guide lens, is formed in a free-form surface having the same focal point as the front optical surface, and internally reflects light reflected by the front optical surface. A rear reflecting surface for internal reflection,
It is characterized by having.

The invention according to claim 2 is the lamp according to claim 1,
The protrusion is
Including a portion where the incident angle of light from the incident surface to the peripheral surface of the protrusion is a critical angle or more;
The light from the incident surface is internally reflected on one peripheral surface and then refracted rearward and obliquely on the other peripheral surface.
The front optical surface reflects light emitted from the protrusions obliquely forward and laterally.

The invention according to claim 3 is the lamp according to claim 1 or 2,
The front optical surface has a low critical angle portion where the incident angle of light from the incident surface is less than approximately the critical angle, and a high critical angle portion where the incident angle is approximately equal to or greater than the critical angle. The low critical angle portion is an aluminum deposition surface.

The invention according to claim 4 is the lamp according to claim 3,
The rear reflection surface is an aluminum vapor deposition surface.

The invention according to claim 5 is the lamp according to claim 4,
At least one of the low critical angle portion of the front optical surface and the rear reflective surface is a half mirror surface.

According to the present invention, after the light emitted from the LED substantially radially forward is incident on the light guide lens without being refracted through the substantially hemispherical incident surface centered on the position of the LED, Is incident on the cone-shaped protrusion, and the object on the lateral side is incident on a hyperboloid front optical surface having a focal point forward on the optical axis. Among these, the light incident on the protrusion is emitted while being refracted forward obliquely through the peripheral surface of the protrusion. On the other hand, after the light incident on the front optical surface is internally reflected backward and obliquely laterally by the front optical surface, it is as if the free-form rear reflection surface having the same focal point as the front optical surface After the light from the focal point is reflected and further internally reflected forward, it is emitted forward while being refracted obliquely through the front optical surface.
Therefore, unlike the conventional case, which has a strong directivity to the front, arbitrary light distribution control can be performed by appropriately setting the rear reflection surface of the free-form surface while appropriately diffusing the emitted light. As a result, a desired irradiation range can be suitably illuminated.

(A) It is sectional drawing of the lamp in embodiment, (b) It is an enlarged view of the E section of (a). It is a figure which shows the light ray locus | trajectory with the lamp in embodiment. It is a figure which shows the light ray locus | trajectory with the lamp in embodiment. It is a figure which shows the modification of the lamp in embodiment. It is sectional drawing of the conventional lamp.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Fig.1 (a) is sectional drawing of the principal part of the lamp 1 in this embodiment, FIG.1 (b) is an enlarged view of the E section of Fig.1 (a).
In the following description, the terms “front” and “rear” mean the direction viewed from the lamp 1 unless otherwise specified.

As shown in FIGS. 1A and 1B, the lamp 1 includes an LED (light emitting diode) 2 that is a light source and a light guide lens 3 that controls light distribution from the LED 2.
Among these, LED2 is arrange | positioned in the state which orient | assigned the light emission surface to the front so that the optical axis Ax may follow the front-back direction, and radiate | emits light substantially radially ahead centering on the said optical axis Ax. More specifically, the LED 2 has a Lambertian directivity, and the amount of light increases as the direction of emission with a smaller emission angle relative to the optical axis Ax.

  The light guide lens 3 is disposed in front of the LED 2 and emits light emitted from the LED 2 forward while controlling light distribution. The light guide lens 3 is formed in a substantially curved plate shape that opens forward. In this embodiment, the light guide lens 3 is formed in an axially symmetric shape with the optical axis Ax of the LED 2 as a rotationally symmetric axis.

  Of the rear surface of the light guide lens 3, an incident surface 31 for allowing light emitted from the LED 2 to enter the light guide lens 3 is provided in the central portion facing the LED 2. The incident surface 31 is formed in a substantially hemispherical shape that opens backward with the position of the LED 2 as the center, and makes the light emitted forward from the LED 2 enter the light guide lens 3 with almost no refraction.

  Further, of the rear surface of the light guide lens 3, substantially the entire rear surface excluding the incident surface 31 around the incident surface 31 internally transmits the light internally reflected backward by the front optical surface 34 described later. The rear reflection surface 32 is reflected. The rear reflecting surface 32 is formed as a free-form surface having a focal point F located in front of the optical axis Ax, and is an aluminum deposition surface on which an aluminum film having a transmittance of approximately 0% is deposited.

  In the front surface of the light guide lens 3, a central cone portion located in front of the LED 2 is provided with a right cone-shaped projection 33 projecting forward with the position on the optical axis Ax as a tip. As will be described later, the projecting portion 33 is a prism portion that reflects or refracts light that has entered the light guide lens 3 from the incident surface 31 on its peripheral surface. Further, the protrusion 33 is formed at a height (vertical angle α) such that the incident angle of light from the incident surface 31 incident on the peripheral surface of the protrusion 33 becomes a critical angle in the peripheral surface. .

  In addition, of the front surface of the light guide lens 3, a substantially entire surface of the front surface except for the projection portion 33 around the projection portion 33 is a front optical surface 34 that reflects or emits light forward. Yes. The front optical surface 34 is formed in a hyperboloid shape having the same focal point F as the rear reflection surface 32.

Of the front optical surface 34, a central portion (thick line portion in the drawing) that is continuous with the outer peripheral edge of the protrusion 33 is a front reflection surface 341. The front reflective surface 341 is an aluminum vapor-deposited surface on which an aluminum film having a transmittance of approximately 0% is vapor-deposited. As will be described later, the light incident on the light guide lens 3 from the incident surface 31 is rearward. While internally reflecting obliquely to the side, the light emitted from the protrusion 33 (circumferential surface) to the diagonally backward side is reflected to the diagonally forward side.
The outer peripheral edge of the front reflection surface 341 is a position on the front optical surface 34 where the incident angle of light that has entered the light guide lens 3 from the incident surface 31 becomes a substantially critical angle. On the other hand, the inner peripheral edge of the front reflecting surface 341 (that is, the outer peripheral edge of the protrusion 33) is reflected by the inner peripheral edge in the obliquely backward direction and the light internally reflected forward by the rear reflecting surface 32. The position is slightly on the side of the position incident on the outer peripheral edge of the reflecting surface 341. That is, the front reflection surface 341 is within the range in which the incident angle of light from the incident surface 31 is less than a substantially critical angle in the front optical surface 34, and the reflected light passes through the rear reflection surface 32. It is formed within a range where it does not enter the front reflection surface 341 again.

  On the other hand, a portion of the front optical surface 34 that is further to the side than the front reflection surface 341 internally reflects the light that has entered the light guide lens 3 from the incident surface 31, and the rear reflection surface 32 internally. An exit surface 342 is provided for emitting the reflected light forward. The exit surface 342 is a portion of the front optical surface 34 where the incident angle of light from the entrance surface 31 is approximately equal to or greater than the critical angle, and thus does not require a reflective film such as an aluminum film. The light from 31 can be internally reflected.

Then, the light irradiation aspect of the lamp 1 is demonstrated.
2 and 3 are diagrams showing a ray trajectory in the lamp 1.

  In the lamp 1, when the LED 2 is caused to emit light, the light emitted from the LED 2 forward in a substantially radial manner enters the light guide lens 3 from the incident surface 31. At this time, since the incident surface 31 is formed in a substantially hemispherical shape centered on the position of the LED 2, the incident light enters the light guide lens 3 with almost no refraction through the incident surface 31.

Of the incident light that has entered the light guide lens 3, the central light around the optical axis Ax enters the protrusion 33 at the front center of the light guide lens 3.
Of the light incident on the protrusion 33, the central light incident on the peripheral surface of the protrusion 33 at an incident angle greater than the critical angle is irradiated forward through the optical path R1, as shown in FIG. Is done. In this optical path R1, after the light incident on the peripheral surface of the protrusion 33 is internally reflected by the peripheral surface on one side of the optical axis Ax, the position of the peripheral surface sandwiches the optical axis Ax. However, the light is emitted out of the light guide lens 3 while being refracted rearward and obliquely by the peripheral surface on the opposite side (the other side). And this light is reflected to the front diagonal side by the front part reflective surface 341 which is an aluminum vapor deposition surface.
On the other hand, of the light incident on the protrusion 33, the side light incident on the peripheral surface of the protrusion 33 at an incident angle less than the critical angle passes through the optical path R2 as shown in FIG. Irradiated forward. In this optical path R2, the light incident on the peripheral surface of the protrusion 33 is emitted forward while being refracted obliquely through the peripheral surface.

  Here, how light incident on the protrusion 33 is distributed to the two optical paths R1 and R2 depends on the height of the protrusion 33, that is, the apex angle α (see FIG. 1B). Yes. The apex angle α is preferably an angle that is neither too small nor too large so that more light passes through the optical path R1. By setting the apex angle α to such an angle, light around the optical axis Ax having a relatively large amount of light can be diffused more laterally.

Of course, the apex angle α of the projection 33 is set in a range in which light deviating from the two optical paths R1 and R2 does not occur.
For example, when the width D1 of the inner peripheral edge of the front reflecting surface 341 is 12.3 mm and the width D2 of the outer peripheral edge is 34.4 mm (see FIG. 1B), the range of the apex angle α serving as the optical path R1 is 83 ° <α <87 °, and the range of the apex angle α that becomes the optical path R2 is 94 ° ≦ α. When the apex angle α is out of these ranges, the light incident on the protrusion 33 is out of either of the two optical paths R1 and R2. Specifically, when the apex angle α is 87 ° ≦ α <94 °, the light is reflected twice by the peripheral surface of the protrusion 33 and returns to the rear. Further, when the apex angle α is α ≦ 83 °, the light is internally reflected and emitted from the peripheral surface of the protrusion 33 and then enters the emission surface 342 on the side of the front reflection surface 341. Resulting in.

Of the incident light that has entered the light guide lens 3, the light that travels to the side of the projection 33 is internally reflected rearward and obliquely by the front optical surface 34 on the front surface of the light guide lens 3. .
More specifically, incident light that is incident on the front optical surface 34 at an incident angle less than approximately the critical angle is irradiated forward through an optical path R3, as shown in FIG. In this optical path R3, the light incident on the front optical surface 34 is first internally reflected diagonally backward by the front reflection surface 341 which is an aluminum vapor deposition surface of the front optical surface 34.
On the other hand, the incident light that is incident on the front optical surface 34 at an incident angle that is approximately equal to or greater than the critical angle is irradiated forward through the optical path R4 as shown in FIG. In this optical path R <b> 4, the light incident on the front optical surface 34 is first internally reflected diagonally backward by the emission surface 342 of the front optical surface 34.
The light internally reflected by the front optical surface 34 (the front reflection surface 341 or the emission surface 342) passes through either the optical path R3 or the optical path R4, and has the same focal point F as the front optical surface 34. After being reflected by the rear reflecting surface 32 having the focal point F as if reflected from the focal point F, it is further internally reflected forward and then emitted forward while being refracted obliquely laterally through the emitting surface 342.

As described above, according to the lamp 1 of the present embodiment, the light emitted substantially radially from the LED 2 to the front is guided without being refracted through the substantially hemispherical incident surface 31 centering on the position of the LED 2. After entering the optical lens 3, the central one enters the conical protrusion 33, and the one on the side of the side is a hyperboloid front portion having a front focal point F on the optical axis Ax. Incident on the optical surface 34. Among these, the light incident on the projection 33 is emitted while being refracted forward through the peripheral surface of the projection 33. On the other hand, the light incident on the front optical surface 34 is internally reflected rearward and obliquely by the front optical surface 34 and then has a free-form curved rear reflection surface having the same focal point F as the front optical surface 34. 32, the light from the focal point F is reflected and further internally reflected forward, and then emitted forward while being refracted obliquely laterally through the front optical surface 34 (exit surface 342).
Therefore, unlike the conventional case that has a strong directivity to the front, it is possible to perform arbitrary light distribution control by appropriately setting the rear reflection surface 32 of a free-form surface while appropriately diffusing outgoing light. As a result, a desired irradiation range can be suitably illuminated.

  Further, the protrusion 33 includes a portion where the incident angle of light from the incident surface 31 to the peripheral surface of the protrusion 33 is not less than the critical angle, and internally reflects the light from the incident surface 31 on one peripheral surface. After that, the light is emitted while being refracted rearward and obliquely on the other peripheral surface, and the front optical surface 34 (front reflection surface 341) reflects the light emitted from the protrusion 33 to the obliquely forward side. The light with a large amount of light emitted from the LED 2 to the central portion around the optical axis Ax can be irradiated obliquely forward and laterally. Therefore, it is possible to realize a uniform light emission mode with less light emission unevenness.

  In addition, the front optical surface 34 includes a front reflection surface 341 in which the incident angle of light from the incident surface 31 is less than a substantially critical angle, and an exit surface 342 in which the incident angle is greater than or equal to a substantially critical angle. Since the front reflective surface 341 is an aluminum vapor deposition surface, the range of the front optical surface 34 that should be the aluminum vapor deposition surface to reflect the light from the incident surface 31 is minimized. Light loss (for example, about 15%) associated with reflection on the aluminum deposition surface can be minimized.

In addition to the front reflection surface 341, the rear reflection surface 32 is also an aluminum vapor deposition surface, so that light incident on the emission surface 342 from the incident surface 31 and reflected by the emission surface 342 and the rear reflection surface 32 (optical path R4). ) Has a larger emission angle from the LED 2 than the light incident on the front reflection surface 341 from the incident surface 31 and reflected by the front reflection surface 341 and the rear reflection surface 32 (in the optical path R3). Although the amount of light is relatively small, the number of times of reflection on the aluminum vapor deposition surface is small, so the amount of light loss is reduced accordingly. Therefore, it is possible to equalize the light amount of the light irradiated through the optical path R3 and the light irradiated through the optical path R4, thereby realizing a uniform light emitting mode with less light emission unevenness.
Furthermore, since the light that has passed through the reflection on the aluminum deposition surface becomes diffused light, it is possible to obtain irradiation light with a softer feeling, unlike light that is simply transmitted through the lens.

  Further, the light emitted mainly from the light path R4 can spread the light forward from the LED 2 to the side so that the front surface of the light guide lens 3 can be widely emitted, so the light from the LED is simply forward. Compared with the case of irradiation, glare can be suppressed by lowering the luminance of the light emitting surface.

  Further, the front surface and the rear surface of the light guide lens 3 mainly have a hyperboloid front optical surface 34 having a focal point F located in front of the optical axis Ax, and the same focal point F as the front optical surface 34. Therefore, a wide-angle light distribution can be realized while reducing the thickness of the front and rear of the light guide lens 3 as compared with, for example, a lens having a convex surface on the front side. . Furthermore, by making the front and rear thicknesses of the light guide lens 3 thinner, the moldability of the light guide lens 3 in the mold can be improved.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

  For example, the light guide lens 3 may not have an aluminum vapor deposition surface as shown in FIG. Specifically, in place of the rear reflective surface 32, a rear reflective surface 32A on which no aluminum film is deposited is provided, and in addition to the front optical surface 34, the front reflective surface 341 is not an aluminum deposited surface. A front optical surface 34A may be provided. With this configuration, light having an incident angle less than the critical angle out of the light incident on the front optical surface 34A from the incident surface 31 is emitted forward while being refracted obliquely laterally through the front optical surface 34A. Will be. Further, the light emitted while being refracted from the protrusion 33 obliquely to the rear side is reentered into the light guide lens 3 from the front optical surface 34A, and is then emitted rearward from the rear reflection surface 32. . Thereby, light can be emitted to the entire circumference of the light guide lens 3 including the rear.

  Moreover, as shown in FIG.4 (b), the light guide lens 3 is good also as what does not provide an aluminum vapor deposition surface, changing the shape of the projection part 33. As shown in FIG. Specifically, in place of the rear reflective surface 32, a rear reflective surface 32B on which an aluminum film is not deposited is provided, and instead of the front optical surface 34, a front reflective surface 341 that is an aluminum vapor deposited surface is provided. The front optical surface 34B is provided such that the incident angle of the light from the incident surface 31 and the incident angle of the light incident on the rear reflecting surface 32B are both greater than or equal to the critical angle. Instead of the protrusion 33, a protrusion 33B whose outer peripheral edge is enlarged to the inner peripheral edge of the front optical surface 34B may be provided. By configuring in this way, it is possible to emit light forward without causing a loss of light amount due to reflection on the aluminum vapor deposition surface, and as a result, it is possible to irradiate light forward while improving the luminous flux utilization factor. it can.

Further, as shown in FIG. 4C, the light guide lens 3 replaces the rear reflection surface 32 and the front reflection surface 341 and reflects a part of the incident light (for example, having a transmittance of 50%). ) A rear reflection surface 32C and a front reflection surface 341C which are so-called half mirror surfaces coated with a reflection film may be provided. By comprising in this way, light can be widely irradiated to arbitrary directions also including back.
Further, only one of the rear reflection surface 32 and the front reflection surface 341 may be a half mirror surface.

  Further, the light guide lens 3 does not have to have an axially symmetric shape with the optical axis Ax as an axis of symmetry, and may be, for example, a rectangular shape in front view, or is elongated along one direction orthogonal to the front-rear direction. It may be a shape.

  Further, the projection 33 does not have to be conical as long as it is formed in a cone shape, and the projection 33 can perform desired light distribution control according to the overall shape of the light guide lens 3, the chip arrangement of the LED 2, and the like. It may be a possible shape.

  Moreover, although the lamp 1 is not specifically limited, For example, as a thing for general lighting, it can apply suitably regardless of indoor and the outdoors. In particular, since a soft light distribution that is easy on the eyes is possible, the present invention can be particularly suitably applied, for example, for illumination in elderly houses, hospitals, or similar facilities.

1 Light 2 LED
Ax Optical axis 3 Light guide lens 31 Incident surface 32, 32A, 32B, 32C Rear reflective surface 33, 33B Protrusion α Apex angle 34, 34A, 34B Front optical surface F Focus 341, 341C Front reflective surface (low critical angle) portion)
342 Output surface (high critical angle part)
R1-R4 optical path

Claims (5)

An LED that has an optical axis along the front-rear direction and emits light substantially radially forward about the optical axis;
A light guide lens disposed in front of the LED and irradiating the light emitted from the LED forward while controlling the light distribution;
A lamp comprising:
The light guide lens is
The light guide lens is provided on a portion of the rear surface of the light guide lens facing the LED, and is formed in a substantially hemispherical shape centered on the position of the LED, and allows the light emitted from the LED to enter the light guide lens. An incident surface;
A conical protrusion projecting forward with the position on the optical axis at the front end of the LED on the front surface of the light guide lens; and
Light that is provided around the protrusion on the front surface of the light guide lens, is formed into a hyperboloid having a focal point located in front of the optical axis, and is incident on the light guide lens from the incident surface. A front optical surface that is capable of emitting light forward while internally reflecting diagonally to the rear side,
The light guide lens is provided around the entrance surface of the rear surface of the light guide lens, is formed in a free-form surface having the same focal point as the front optical surface, and internally reflects light reflected by the front optical surface. A rear reflecting surface for internal reflection,
The lamp characterized by having. The protrusion is
Including a portion where the incident angle of light from the incident surface to the peripheral surface of the protrusion is a critical angle or more;
The light from the incident surface is internally reflected on one peripheral surface and then refracted rearward and obliquely on the other peripheral surface.
2. The lamp according to claim 1, wherein the front optical surface reflects light emitted from the projecting portion obliquely forward and laterally.   The front optical surface has a low critical angle portion where the incident angle of light from the incident surface is less than approximately the critical angle, and a high critical angle portion where the incident angle is approximately equal to or greater than the critical angle. The lamp according to claim 1, wherein the low critical angle portion is an aluminum vapor deposition surface.   The lamp according to claim 3, wherein the rear reflection surface is an aluminum vapor deposition surface.   5. The lamp according to claim 4, wherein at least one of the low critical angle portion of the front optical surface and the rear reflection surface is a half mirror surface.

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