KR20140040099A - Light-emitting diode lighting device and material for light-emitting diode lighting - Google Patents

Abstract

A plurality of LEDs 11 are arranged to emit light in the same direction. A plurality of optical systems 12 are provided corresponding to each LED 11 so as to convert the numerical aperture of the emitted light of each LED 11. Representative dimensions of the emitting surface of each LED 11 are L, intervals between the LEDs 11 adjacent to each other, and representative dimensions of each optical system 12 are Doled, intervals between the optical systems 12 adjacent to each other Io When the numerical aperture of light irradiated from the device is NAout, 0.8 L / NAout ≦ Do ≦ 1.1L / NAout, Io ≦ Iled, and Io ≦ Do.

Description

LIGHT-EMITTING DIODE LIGHTING DEVICE AND MATERIAL FOR LIGHT-EMITTING DIODE LIGHTING}

TECHNICAL FIELD The present invention relates to a light emitting diode illumination device and a light emitting diode illumination member used for a light source, a projector, or the like for an optical fiber illumination.

Background Art Conventionally, HID lamps and ellipsoidal mirrors have been used for high-brightness lighting devices used for light sources for optical fiber illumination, projectors, and the like. The area of the irradiated surface of such a lighting device is small, about 10-20 mm in diameter in a light source for optical fiber illumination, and 24 x 18 mm in a 35 mm movie film projector. The illuminating device is required to irradiate light to this small area with high luminance efficiently. In addition, the numerical aperture of the light to be irradiated needs to be equal to or smaller than the numerical aperture of the optical fiber in the light source device for optical fiber illumination and less than or equal to the numerical aperture of the projection lens in the projector.

Such a lighting apparatus has conventionally been proposed using a light emitting diode (LED). For example, since the output of the light emitting diode 1 chip is smaller than that of the HID lamp, a plurality of light emitting diodes are arranged on a plane, so that the light of each light emitting diode is parallel in the input lens in the same direction, and then one output is obtained. After condensing with a lens to irradiate an optical fiber (for example, see Patent Document 1), or converting the numerical aperture into a taper rod for light of a plurality of light emitting diodes arranged on the same plane, It is proposed to irradiate an optical valve (for example, refer patent document 2).

Patent Document 1: Japanese Patent Publication No. 2009-15319 Patent Document 2: Japanese Patent Application Laid-Open No. 2000-214532

The illumination device described in Patent Document 1 applies an imaging optical system to a plurality of light emitting diodes, and the total luminous flux that emits light increases as the number of light emitting diodes increases. However, since the optical system is complicated and the distance between the light emitting surface of the light emitting diode and the illuminated surface is long, there is a problem in that the luminance is greatly reduced due to the aberration of the optical system and the efficiency is also low. Moreover, although the illumination device of patent document 2 uses the new optical system which does not use a lens, there exists a problem that the consideration which raises efficiency by reducing a reduction of a brightness | luminance is not made.

The present invention has been made in view of such a problem, and it is possible to suppress a decrease in the luminance of the irradiation surface of the light emitting diode with respect to the light emitting surface of the light emitting diode, so that the efficiency of light for irradiating the irradiation surface with respect to the total luminous flux of the light emitting diode can be improved. An object of the present invention is to provide a diode lighting device and a light emitting diode lighting member.

In order to achieve the above object, a light emitting diode illumination device according to the present invention is a light emitting diode illumination device having an optical system provided so as to convert a numerical aperture of a light emitting diode and an outgoing light of the light emitting diode, wherein the light emission is When the representative dimension of the light emitting surface of the diode is L, the representative dimension of the optical system is Do, and the numerical aperture of the light irradiated from the device is NAout,

0.8L / NAout≤Do≤1.1L / NAout

.

Particularly, in the LED lighting apparatus according to the present invention, the light emitting diode is formed of a plurality, and the light emitting surface is disposed on the same plane so as to emit light in the same direction, respectively, and the optical system is made of a plurality of, The representative dimension of the light emitting surface of each light emitting diode is denoted by L, the distance between adjacent light emitting diodes is denoted by Iled, the representative dimension of each optical system is denoted by Do, When the interval between the optical systems to be set is Io and the numerical aperture of the light irradiated from the device is NAout,

0.8L / NAout≤Do≤1.1L / NAout

Io≤Iled

Io≤Do

.

The emission pattern of light emitting diodes has a Lambert distribution. When the numerical aperture of the optical system is NAin, the efficiency ηin at which the light emitted from the light emitting diode is incident on the optical system is a value obtained by integrating the Lambert distribution up to an angle with respect to the incident numerical aperture.

ηin = Sin ² θ = NAin ²

. In Fig. 19, there is shown a graph of incidence efficiency with respect to an optical system having a light intensity of the light emitting diode output light and a numerical aperture up to the angle with respect to the angle? Between the normal line of the light emitting diode and the emitted light. When NAin = 1, the incident efficiency ηin becomes 100%, and the closer to this value, the higher the incident efficiency ηin.

On the other hand, the emission numerical aperture of the optical system needs to match the irradiation numerical aperture NAout of the apparatus. The irradiated numerical aperture NAout is equal to or smaller than the numerical aperture (0.2 is used for quartz fibers and 0.5 is used for multicomponent fibers) of the optical fiber connected by the optical fiber light source. The numerical aperture is 0.34) or less with the projection lens of F1.4.

The light emitting diode illumination device according to the present invention can suppress the numerical aperture of the optical system and match the irradiation numerical aperture NAout of the apparatus. For this reason, the fall of the brightness | luminance of the irradiation surface with respect to the light emitting surface of a light emitting diode can be suppressed, and the efficiency of the light which irradiates the irradiation surface with respect to the total luminous flux of a light emitting diode can be improved. In addition, the light emitting surface arranged on the same plane includes not only the case where the light emitting surface is arrange | positioned on the one plane with the light emitting surface of each light emitting diode, but also the case where it is arrange | positioned in the range slightly deviated from the plane. Moreover, it is preferable that it is L / NAout * Do.

In the LED lighting apparatus according to the present invention, the optical system is composed of a lens having a positive refractive power, the light emitting diode is disposed in the focal point or near the focus of the optical system, the representative dimension of the optical system Do When the diameter of, the focal length of the lens is f,

Do ≒ 2f ≒ L / NAout

It is also preferable.

In particular, in the case where a plurality of light emitting diodes and optical systems are made, in the light emitting diode lighting apparatus according to the present invention, each optical system is composed of a lens having a positive refractive power, and each light emitting diode is respectively located at or near the focus of each optical system. When the representative dimension Do of each optical system is made into the diameter of the said lens, and the focal length of the said lens is f,

Do ≒ 2f ≒ L / NAout

Io = Iled≤Do

It is also preferable.

When such an optical system is constituted by a lens, the reduction of the luminance of the irradiation surface of the light emitting diode to the light emitting surface of the light emitting diode can be suppressed by using the lens, and the efficiency of light for irradiating the irradiation surface to the total luminous flux of the light emitting diode can be improved. . Moreover, in order to raise the efficiency of irradiation light further, it is preferable that a light emitting diode is arrange | positioned in the focal position of a lens, and it is comprised by the collimate optical system which made the vicinity of the emission position of a lens into an irradiation surface. In this case, the lens system can be designed with a simple configuration such that the sine condition is satisfied and the incident numerical aperture is close to one. By using each light emitting diode and a collimating optical system as a unit and arranging this unit without gap on a plane, a larger surface can be irradiated with high illumination. Further, in order to make the illuminance of the irradiation surface uniform, a mixing rod may be disposed on the emission side of each lens.

Further, in the LED lighting apparatus according to the present invention, each optical system consists of a tapered rod, the representative dimension Do of each optical system is taken as the exit dimension of the tapered rod, and the interval Io between the adjacent optical systems is the tapered rod exit. When the inlet dimension of the tapered rod is Din, the opening angle of the tapered rod is φ, and the distance between each light emitting diode and each optical system is t,

Do ≒ Din / NAout ≒ Io = Iled

φ <NAout / 10

L≤Din≤1.1L

0 <t≤0.2L

It is also preferable.

In addition, in the LED lighting apparatus according to the present invention, each optical system is composed of a tapered rod, the representative dimension Do of each optical system is the exit dimension of the tapered rod, and the distance Io between the adjacent optical systems is the tapered rod. When the inlet dimension of the tapered rod is Din,

Do ≒ Din / NAout ≒ Io <Iled

It is also preferable.

When such an optical system is composed of a tapered rod, the tapered rod can be used to suppress a decrease in the luminance of the irradiation surface of the light emitting diode with respect to the light emitting surface of the light emitting diode, thereby improving the efficiency of light irradiating the irradiation surface with respect to the total luminous flux of the light emitting diode. You can increase it. Moreover, when the shape of the light emitting surface of a light emitting diode is square, it is preferable that a taper rod is also square. It is preferable that the unit which consists of a set of a light emitting diode and a tapered rod is arrange | positioned in each lattice point of a square grating with respect to the surface parallel to a light emitting surface.

In the light emitting diode illumination device according to the present invention, each optical system is composed of a complex parabolic reflector (condenser), and a representative dimension Do of each optical system is an exit dimension of the complex parabolic reflector, When the inlet dimension Din of the compound parabolic condenser and the distance between each light emitting diode and each optical system are t,

Do ≒ Din / NAout ≒ Io = Iled

L≤Din≤1.1L

0 <t≤0.2L

It is also preferable.

When this optical system is constituted by a complex paraboloid concentrator, it is possible to suppress the decrease in luminance of the illuminated surface of the light emitting diode by using the complex paraboloid concentrator, and it is possible to reduce the luminance of the light irradiated to the illuminated surface of the light emitting diode The efficiency can be improved. Moreover, when the shape of the light emitting surface of a light emitting diode is square, it is preferable that a composite parabolic collector is also square. It is preferable that the unit which consists of a set of a light emitting diode and a composite parabolic light collector for the surface parallel to a light emitting surface is arrange | positioned at each lattice point of a square grating.

The light emitting diode illumination member which concerns on this invention is a light emitting diode illumination member which comprises the light emitting diode illumination device which concerns on this invention, and satisfy | fills 2L <Iled <10L so that each light emitting diode can respectively emit light in the same direction. And each optical system is configured such that each optical system can be brought close to 0.4L in the light emitting direction of each light emitting diode with respect to each light emitting diode.

According to the light emitting diode illumination member which concerns on this invention, the light emitting diode illumination device which concerns on this invention can be comprised easily with a simple structure. The light emitting diode illuminating member according to the present invention can improve the heat dissipation by distributing the light emitting diodes, thereby achieving the performance of each light emitting diode. In the light emitting diode illumination member according to the present invention, it is preferable that the light emitting diode is arranged in the air without being sealed by a medium having a large refractive index. In addition, it is preferable not to arrange a structure such as a bonding wire in the light emitting direction as much as possible so that the optical system can be arranged in the light emitting direction of the light emitting diode. It is preferable that the board | substrate which arranges a light emitting diode is comprised from materials with good heat dissipation, such as aluminum and copper. Although the interval Iled of a light emitting diode is determined by the irradiation numerical aperture of an illumination system, it is preferable that it is 2L <Iled <10L from the irradiation numerical aperture which is easy to use as a high brightness illuminating device from 0.1-0.5.

According to the present invention, it is possible to suppress the reduction of the luminance of the irradiated surface to the light emitting surface of the light emitting diode and to increase the efficiency of light irradiating the irradiated surface to the total luminous flux of the light emitting diode, and for the LED lighting device It is possible to provide the member.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a geometrical optical ray tracing of (a) light emitted from a light emitting diode, showing a light emitting diode illumination device according to a first embodiment of the present invention, and (b) a perspective view.
FIG. 2 is a ray tracing side view of one unit composed of a light emitting diode and an optical system of the light emitting diode illuminating device shown in FIG. 1.
FIG. 3 is a graph showing the correlation between the numerical aperture and light beam height of the light emitting diode and optical system shown in FIG. 2.
4 is a graph showing the illuminance distribution diagram of the (a) irradiation surface of the light emitting diode and the optical system shown in FIG. 2 and (b) the illuminance distribution in the horizontal axis direction.
FIG. 5 is an illuminance distribution diagram of a surface 1 m away from the irradiation surface of the light emitting diode and optical system shown in FIG. 2.
6 is an illuminance distribution diagram of (a) the irradiated surface and (b) an illuminance distribution diagram of the surface 1 m away from the irradiated surface of the light emitting diode illuminating device shown in FIG. 1.
Fig. 7 is a perspective view showing a modification of the light emitting diode illuminating device of the first embodiment of the present invention.
FIG. 8 is an illuminance distribution diagram of (a) the irradiation surface of the light emitting diode illuminating device shown in FIG. 7 and (b) an illuminance distribution diagram of the surface 1 m away from the irradiation surface.
9 is a perspective view showing a light emitting diode illuminating device according to a second embodiment of the present invention.
FIG. 10: is a perspective view which shows one unit which consists of a light emitting diode and a taper rod of the light emitting diode illuminating device shown in FIG.
FIG. 11 is an illuminance distribution diagram of (a) the irradiation surface of the light emitting diode and the tapered rod shown in FIG. 10, and (b) an illuminance distribution diagram on the screen 1 m away from the tapered rod.
FIG. 12 is an illuminance distribution diagram of (a) the irradiation surface of the light emitting diode illuminating device shown in FIG. 9, and (b) an illuminance distribution diagram on the screen 1 m away from the tapered rod.
It is a perspective view which shows the modification of the light emitting diode illuminating device of 2nd Embodiment of this invention.
It is a perspective view which shows the light emitting diode illuminating device of 3rd Embodiment of this invention.
FIG. 15 is a perspective view showing one unit composed of a light emitting diode and a compound parabolic mirror of the light emitting diode illuminating device shown in FIG. 14.
It is a side view which shows one surface of the compound parabolic mirror of the light emitting diode illuminating device shown in FIG.
FIG. 17 is an illuminance distribution diagram of (a) the irradiation surface and (b) an illuminance distribution diagram on the screen 1 m away from the irradiation surface of the light emitting diode and the composite parabolic mirror shown in FIG. 15.
It is a perspective view which shows the light emitting diode illumination member of embodiment of this invention.
19 is a graph showing changes in the luminous intensity and incident efficiency of light emitting diode output light with respect to an angle θ formed between the normal line of the light emitting diode and the emitted light.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

1 to 8 show a light emitting diode illumination device according to a first embodiment of the present invention.

As shown in FIG. 1, the LED lighting apparatus 10 has a plurality of LEDs (light emitting diodes) 11, a plurality of optical systems 12, and a mixing rod 13.

The LEDs 11 are comprised of seven pieces, are arrange | positioned so that a light emitting surface may be coplanar, and are arranged in a zigzag form centering on the vertex center of a hexagon. Each LED 11 emits light in the same direction. Each optical system 12 is composed of two convex lenses 21a and 21b having positive refractive power, and is provided corresponding to each LED 11 so as to convert the numerical aperture of the emitted light of each LED 11. Each optical system 12 is arranged in proximity to the light emitting surface of each LED 11. The mixing rod 13 has a hexagonal columnar shape, and is disposed on the emission side of each optical system 12.

As a specific example, as shown in FIG. 2, each LED 11 has a square light emitting surface, and the typical dimension of the light emitting surface is the dimension L = 2 mm on one side. The lens 21a, 21b of each optical system 12 consists of 2 groups of 2 pieces, the focal length f is 4 mm, and the lens diameter Do (= Dlens, the largest diameter which a light ray passes in the lens 21b exit surface) of the typical dimension is 8 mm. The irradiation surface 14 on the exit side of the optical system 12 is about 8 mm in diameter. therefore,

Dlens = Do = 2f

to be.

In addition, assuming that the lens satisfies the sine condition,

NAout = L / 2f

NAout = 2 / (2x4) = 0.25 in the diagonal direction of the LED 11 and NAout = 2.8 / (2x4) = 0.35 in the diagonal direction of the LED 11.

Each lens 21a, 21b of the optical system 12 is arrange | positioned with the convex side facing the irradiation surface 14. The radius of curvature r (mm), the center thickness and the interval d (mm), the refractive index n, and the Abbe number v of each lens 21a and 21b are shown below. Here, r1 and r2 are the curvature radii of the LED 11 side and the irradiation surface 14 side of the lens 21a, respectively, and r3 and r4 are the LED 11 side and the irradiation surface 14 side of the lens 21b, respectively. Is the radius of curvature. d0 is the distance between the LED 11 and the lens 21a in the optical axis of the lenses 21a and 21b, d1 and d3 are the center thicknesses of the lenses 21a and 21b, respectively, and d2 is the lens 21a and the lens ( The space | interval of 21b) and d4 are the space | interval of the lens 21b and the irradiation surface 14. As shown in FIG. n1 and n2 are the refractive indices of the lenses 21a and 21b, respectively, and v1 and v2 are the Abbe's numbers of the lenses 21a and 21b, respectively. k4 is a cone constant of the lens 21b.

                 d0 = 0.5

r1 = ∞ d1 = 2.0 n1 = 1.5168 v1 = 64.17

r2 = −2.5 d2 = 1

r3 = ∞ d3 = 4.8 n2 = 1.8467 v2 = 23.78

r4 = -5.42 d4 = 0.5 k4 = -1.33

3 shows the distance from the sin θ of the light beam emitted from the center of the LED 11 and the optical axis of the light beam on the irradiation surface 14. Here, θ is an angle formed between the light beam and the optical axis on the light emitting surface of the LED 11. Under sinusoidal conditions, the height of the ray (distance from the optical axis) h is

h = fsinθ

. Here, f is the focal length (f = 4 mm) of the optical system 12. It can be seen from FIG. 3 that the sine conditions are almost satisfied.

4 and 5 show the results of a Monte Carlo simulation under the following conditions.

LED dimensions 2mm corner

LED luminous flux 314 lm

LED brightness 25 cd / mm ²

Screen dimensions 10mm angle (Fig. 4)

                                 1 m corner (Fig. 5)

1 million rays

Ignore Fresnel Loss

4 shows the illuminance distribution of the irradiated surface 14, and the irradiated diameter of 10% or more illuminance is 8.4 mm. 5 shows the illuminance distribution of the surface 1 m away from the irradiated surface 14, and an irradiation dimension of 10% or more illuminance is 520 mm angle. The irradiation surface 14 can be seen as a light emitting surface, the luminance (optical axis direction average luminance) is 1250 / (4.2 × 4.2 × 3.14) = 22.6 cd / mm ² , and about 10 with respect to the light emitting surface of the LED 11. % Is decreasing. The irradiation efficiency (= total luminous flux of the luminous flux / LED 11 that reached the irradiation surface 14) was 87%.

Irradiation numerical aperture,

sin (tan ^-1 (260/1000) = 0.252 (stool direction)

sin (tan ^-1 (380/1000) = 0.355 (diagonal)

The increase in numerical aperture was less than 2%. The decrease in luminance can be said to be an irradiation efficiency component.

Thus, in the structure of FIG. 2, the exit numerical aperture of the optical system 12 can be suppressed, and it can match with irradiation numerical aperture NAout. For this reason, the fall of the brightness | luminance of the irradiation surface 14 with respect to the light emitting surface of LED11 can be suppressed, and the efficiency of the light which irradiates the irradiation surface 14 with respect to the total luminous flux of LED11 can be improved. . In addition, when there is one LED, the light emitting diode illuminating device 10 can be comprised by FIG.

As shown in FIG. 1, the light emitting diode illuminating device 10 densely arranges the group of the LED 11 and the optical system 12 shown in FIG. 2 in 7 units on a plane. The spacing of the units, that is, the spacing Iled between the LEDs 11 adjacent to each other, and the spacing Io between the optical systems 12 adjacent to each other, are 8 mm equal to the lens diameter Do (Io = Iled = Do = 8 mm). The irradiation rod 14 of the unit is irradiated with the mixing rod 13 of the regular hexagonal column whose side is 12.6 mm, and the output surface of the mixing rod 13 is used as the irradiation surface 15 of the LED illuminating device 10. .

6 shows the results of Monte Carlo simulation under the following conditions.

LED dimensions 2mm corner

LED Full Beam 314 lm

LED brightness 25 cd / mm ²

7 LED quantity

Screen dimensions 30mm angle (Fig. 6 (a))

                               1m corner (Fig. 6 (b))

1 million rays

Ignore Fresnel Loss

Fig. 6A shows the illuminance distribution of the irradiation surface 15, and the irradiation shape is a regular hexagon with one side of 13.2 mm. FIG. 6 (b) shows the illuminance distribution of the surface 1 m away from the irradiated surface 15, and the irradiated dimension of 10% illuminance or more is 620 mm in the opposite direction. The brightness of the irradiation surface 15 is

8500 / (13.2 × 13.2 × 1.73 / 2/2 × 6)

= 18.81 cd / mm ²

The decrease in brightness was 25%. The irradiation efficiency was 89%.

Irradiation numerical aperture,

sin (tan ^-1 (310/1000) = 0.296 (stool direction)

sin (tan ^-1 (380/1000) = 0.355 (diagonal)

The increase in the numerical aperture was 18% in the stool direction and 1% in the diagonal direction. As the irradiation area and irradiation numerical aperture by the mixing rod 13 increase, the brightness decreases.

7, the light emitting diode illumination device 10 has a structure in which the distance between the units constituted by the LED 11 and the optical system 12, that is, the distance Iled between the adjacent LEDs 11, The interval Io between (12) may be made smaller than the lens diameter Do (Io = Iled <Do). In the case of Fig. 7, Io = Iled = 6.92 mm = 0.86 Do. In this case, one side of the mixing rod 13 of the regular hexagon is 11 mm.

In FIG. 8, the result of Monte Carlo simulation in the conditions similar to FIG. 6 is shown. Fig. 8A shows the illuminance distribution of the irradiation surface 15, and the irradiation shape is a regular hexagon with one side 11.4 mm. FIG. 8B shows the illuminance distribution of the surface 1 m away from the irradiated surface 15, and an irradiation dimension of 10% or less illuminance is 560 mm in the opposite direction. The brightness of the irradiation surface 15 is

7800 / (11.4 × 11.4 × 1.73 / 2/2 × 6)

= 23.1 cd / mm ²

Although the decrease in luminance was small at 7%, the irradiation efficiency was low at 80%.

At Io = 0.8 Do, the luminance decrease was 0% and the irradiation efficiency was 71%. Up to this condition is the range which can be used as a high brightness lighting apparatus.

Irradiation numerical aperture,

sin (tan ^-1 (280/1000) = 0.27 (stool direction)

sin (tan ^-1 (380/1000) = 0.355 (diagonal)

The increase in the irradiation numerical aperture is 8% in the opposite direction and 1% in the diagonal direction, which is smaller than that in the case of FIG. 6. It's a design that focuses on high brightness rather than efficiency. Further, since the illuminance distribution of the incidence portion of the mixing rod 13 is relatively uniform, there is also an advantage that the mixing rod 13 can be shortened.

9 to 13 show a light emitting diode illumination device according to a second embodiment of the present invention.

As shown in FIG. 9, the LED lighting apparatus 30 includes a plurality of LEDs 11 and a plurality of optical systems 12. In the following description, the same components as those of the light emitting diode illumination device 10 according to the first embodiment of the present invention are denoted by the same reference numerals, and redundant explanations are omitted.

The LEDs 11 are comprised of six pieces, arrange | positioned so that a light emitting surface may be on the same plane, and are arranged at equal intervals three by one at the top and the bottom. Each LED 11 emits light in the same direction. Each optical system 12 is comprised from the taper rod 31, and is provided corresponding to each LED 11 so that the numerical aperture of the emission light of each LED 11 may be converted.

In a specific example, as shown in FIG. 10, the incident surface of the square tapered rod 31 is arrange | positioned in the front of the square light emitting surface of each LED 11, and the irradiation surface 14 is arrange | positioned in the front of the emission surface.

In FIG. 11, the result of Monte Carlo simulation in the following conditions is shown.

LED dimensions 2mm corner

LED luminous flux 314 lm

LED brightness 25 cd / mm ²

LED taper rod thickness 0.2 mm

Taper rod-surface clearance 0.5 mm

Taper Rod Inlet Dimensions Din 2 mm

Taper rod outlet dimension Dout 5 mm, 8 mm

Taper Rod Opening Angle

          φ / (Din / Dout) 0.01, 0.1, 0.2

Taper Rod Material BK7

Screen dimensions 10mm angle (Fig. 11 (a))

                              1m corner (Fig. 11 (b))

1 million rays

Ignore Fresnel Loss

In FIG.11 (a), the roughness distribution of the irradiation surface 14 in the case of Din / Dout = 0.25 and (phi / (Din / Dout) = 0.1) is shown. Irradiation shape is a square of the dimension of the same grade as an exit dimension, and roughness distribution is substantially uniform. Even under other conditions, the roughness shape is a square of the same size as the exit dimension, and the illuminance distribution is almost uniform. In FIG. 11B, the illuminance distribution on the screen 1 m away from the tapered rod 31 is shown.

The brightness of the irradiation surface 14 is

1600 / (8.4 × 8.4) = 22.8 cd / mm ²

                    (When Din / Dout = 0.25)

600 / (5.4 × 5.4) = 20.6 cd / mm ²

                    (When Din / Dout = 0.4)

to be. The decrease in luminance is caused by the enlargement of the irradiation area due to the enlargement of light between the taper rod 31 and the irradiation surface 14 at a distance of 0.5 mm.

Table 1 shows the irradiation numerical aperture of 10% roughness or more.

As shown in Table 1, the irradiation numerical aperture becomes close to Din / Dout when the opening angle is small, and the angular distribution of the irradiation light has a shape that rises to zero above the numerical aperture and sharply stands near the numerical aperture. The larger the opening angle, the dull the distribution, and the larger the numerical aperture than Din / Dout. In this way, the irradiation numerical aperture has a large correlation with φ / (Din / Dout), and if φ / (Din / Dout) = 0.1 or less, the distribution is sensitive, and thus it is understood that the irradiation numerical aperture is preferable as a high-brightness lighting device.

Table 2 shows the change in irradiation efficiency due to the gap between the LED 11 and the tapered rod 31.

In Table 2, the relative value at the time of making LED dimension 1 also shows with LED-taper rod space | interval and taper rod inlet dimension. As shown in Table 2, when the distance t between the LED 11 and the tapered rod 31 is close to zero, the irradiation efficiency is very high, but there is a limit to approach zero. If the inlet dimension of the tapered rod 31 is enlarged, irradiation efficiency will increase, but since an outlet dimension also becomes large, luminance will become small in inverse proportion to the square of an inlet dimension. In the high-brightness lighting apparatus, since the luminance deterioration is required to be 30% or less and the irradiation efficiency is 70% or more, in Table 2, the inlet dimension of the tapered rod 31 is 1.1 times or less of the LED dimension (L≤Din≤1.1L). ), The LED-taper rod spacing is preferably 0.2 times or less (0 &lt; t? 0.2 L) of the LED dimension. Here, the LED-taper rod spacing is n times in the medium of refractive index n by the distance in air.

As shown in FIG. 9, the LED lighting apparatus 30 groups the group of the LED 11 and the taper rod 31 shown in FIG. 10 at the same interval as the taper rod outlet dimension Dout (Io = Dout = Do). By arranging square, 6 times the area of FIG. 10 can be irradiated.

In FIG. 12, the result of Monte Carlo simulation in the following conditions is shown.

LED dimensions 2mm corner

LED Full Beam 314 lm

Quantity of 6 LEDs

LED brightness 25 cd / mm ²

LED taper rod thickness 0.2 mm

Taper rod-surface clearance 0.5 mm

Taper Rod Inlet Dimensions Din 2 mm

Taper Rod Outlet Dimension Dout 8 mm

Taper Rod Outlet Thickness 8 mm

8 mm thickness of LED

Taper Rod Opening Angle

          φ / (Din / Dout) 0.1

Taper Rod Material BK7

Screen dimensions 30mm angle (Fig. 12 (a))

                                    1 m corner (Fig. 12 (b))

1 million rays

Ignore Fresnel Loss

12A shows the illuminance distribution of the irradiation surface 15. 12 (b) shows the illuminance distribution on the screen 1 m away from the tapered rod 31. The luminance of the irradiation surface 15 is 9600 / (24.4 × 16.4) = 24.0 cd / mm ² , and the enlargement of the irradiation area caused by the gap between the tapered rod 31 and the irradiation surface 15 is outside around six tapered rods. Since it does not occur, the deterioration in luminance becomes smaller than in the case of FIG.

In addition, as shown in FIG. 13, the LED lighting apparatus 30 may make the space | interval of LED11 and the space | interval of the inlet of taper rod 31 wider than the space | interval of the outlet of taper rod 31. As shown in FIG. In this case, the heat dissipation design becomes easy by emptying the space | interval of LED11.

14 to 17 show a light emitting diode illumination device according to a third embodiment of the present invention.

As shown in FIG. 14, the LED lighting apparatus 50 has a plurality of LEDs 11 and a plurality of optical systems 12. In addition, in the following description, the same code | symbol is attached | subjected to the same structure as the light emitting diode illumination device 10 and 30 of 1st and 2nd embodiment of this invention, and the overlapping description is abbreviate | omitted.

The LEDs 11 are comprised of six pieces, arrange | positioned so that a light emitting surface may be on the same plane, and are arrange | positioned at the same space | interval three by three at the top and the bottom. Each LED 11 emits light in the same direction. Each optical system 12 is comprised by the compound parabolic mirror (composite parabolic condenser) 51, and is provided corresponding to each LED 11 so that the numerical aperture of the emission light of each LED 11 may be converted.

In a specific example, as shown in FIG. 15, the entrance surface of the square compound parabolic mirror 51 is arrange | positioned in the front of the square light emitting surface of each LED 11, and the irradiation surface 14 is arrange | positioned in the front of the emission surface. do. In FIG. 16, the shape of one surface of the compound parabolic mirror 51 is shown. As shown in Fig. 16, 61 is the parabolic mirror, 62 is the focal position of the parabolic mirror, 63 is the optical axis of the parabolic mirror, 64 is the optical axis of the compound parabolic mirror 51, φcpc is the optical axis of the parabolic mirror and the compound parabolic mirror 51 Din is the inlet dimension of the compound parabolic mirror 51, and Dout is the exit dimension of the compound parabolic mirror 51.

The square compound parabolic mirror 51 is comprised by four parabolic mirrors 61 rotated 0, 90, 180, and 270 times about the optical axis 64 of the compound parabolic mirror 51. As shown in FIG. Irradiation numerical aperture NAout of the square compound parabolic mirror 51 is

NAout = sin (φcpc) = Din / Dout

to be.

In FIG. 17, the result of Monte Carlo simulation in the following conditions is shown.

LED dimensions 2mm corner

LED Full Beam 314 lm

LED brightness 25 cd / mm ²

LED-composite parabolic diameter 0.2 mm

Compound parabolic mirror-surface clearance 0.5 mm

Compound Parabolic Inlet Dimensions Din 2 mm

Composite diameter mirror exit dimension Dout 8 mm

Screen dimensions 10mm angle (Fig. 17 (a))

                                      1m corner (Fig. 17 (b))

1 million rays

100% reflectivity

FIG. 17A shows the illuminance distribution of the irradiation surface 14, and FIG. 17B shows the illuminance distribution of the screen 1 m away from the irradiation surface 14. The brightness of the irradiation surface 14 is

1530 / (8.4 × 8.4) = 21.7 cd / mm ²

The decrease in luminance is 13% and the irradiation efficiency is 83.5%.

Irradiation numerical aperture,

sin (tan ^-1 (260/1000) = 0.252 (stool direction)

sin (tan ^-1 (350/1000) = 0.33 (diagonal)

to be. The illuminance distribution of the irradiated surface 14 is characterized by no deterioration of the numerical aperture, such as the tapered rod 31, although the center is about half of the periphery.

Irradiation efficiency becomes Table 2 like the taper rod 31. FIG. Therefore, the inlet dimension of the compound parabolic mirror 51 is 1.1 times or less (L ≦ Din ≦ 1.1 L) of the LED 11 dimension, and the LED-composite parabolic spacing is 0.2 times or less (0 <t) of the LED 11 dimension. ≤ 0.2 L) is preferred. In addition, although the hollow composite parabolic mirror 51 was shown here, the composite parabolic mirror using total internal reflection of glass may be sufficient.

As shown in FIG. 14, the LED lighting device 50 uses the LED 11 and the compound parabolic mirror 51 shown in FIG. 15 at intervals equal to the compound parabolic exit dimension Dout (Io = Dout = Do) 6. By arranging the tetragons, the area six times as large as in FIG. 15 can be irradiated. Also in this case, similarly to the light emitting diode illuminating device 30 using the tapered rod 31, the luminance is higher than in the case of FIG.

18 shows a light emitting diode illumination member according to an embodiment of the present invention.

As shown in Fig. 18, the LED lighting element 70 is formed by densely arranging seven LEDs 11 on the flat substrate 71 at equal intervals at intervals of Iled = 8 mm. In addition, in the following description, the same code | symbol is attached | subjected to the structure same as the light emitting diode illumination device 10, 30, 50 of 1st, 2nd, and 3rd embodiment of this invention, and the overlapping description is abbreviate | omitted.

Each LED 11 is arranged at intervals Iled of 2 L &lt; Iled &lt; Further, if the same area as the seven LEDs 11 is one LED, a chip of 5.3 mm angle is obtained. If you make this LED look like a 2mm angle LED, the amount of heat will increase by 7 times. At this time, the heat radiation resistance decreases by 2 / 5.3 = 1 / 2.7 times, but as a result, the temperature rise of the chip increases by 5.3 / 2 = 2.7 times. Here, the upper limit of the chip temperature of the LED is usually 150 ° C., in order to keep this, the amount of heat generated must be reduced to 1 / 2.7. As a result, even when the emission area is 7 times, the total luminous flux is only 2.7 (square root of 7) times.

Many proposals have been made for heat dissipation, but there are limitations due to heat dissipation in order to increase the light emitting area of high-brightness LEDs. For this reason, in the light emitting diode illuminating member 70, the LEDs 11 are distributed and arranged to increase heat dissipation, and as a result, the performance of the individual LEDs 11 can be achieved.

The flat substrate 71 is aluminum or copper with good heat dissipation.

Hereinafter, the light emitting surface of the LED 11 with the same glass, the same focal length, and the same diameter as the light emitting diode illuminating device 10 of the first embodiment of the present invention using the light emitting diode illuminating member 70. The design example when the distance to the 1st surface of the optical system 12 is set to d0 = 0.8 is shown.

                      d0 = 0.8

r1 = ∞ d1 = 2 n1 = 1.5168 ν1 = 64.17

r2 = -3.2 d2 = 1

r3 = ∞ d3 = 3.8 n2 = 1.8467 v2 = 23.78

r4 = -5.1 d4 = 0.5 k4 = -1.6

Similarly, the design example at the time of making d0 = 1 is shown.

                      d0 = 1

r1 = ∞ d1 = 2.4 n1 = 1.5168 v1 = 64.17

r2 = －3.6 d2 = 1

r3 = ∞ d3 = 2.8 n2 = 1.8467 v2 = 23.78

r4 = -5.3 d4 = 0.5 k4 = -1.9

Table 3 shows the Monte Carlo simulation results under the same conditions as the LED lighting apparatus 10 (d0 = 0.5) in such a design.

As shown in Table 3, when the distance d0 from the LED 11 to the first surface of the optical system 12 becomes large, there is no change in luminance but the irradiation efficiency is lowered. According to Table 3, it is preferable that distance d0 to a 1st surface is 0.4 times or less of the dimension L of LED11. For this reason, the wiring member, cover glass, structure, etc. of the LED 11 must be within 0.4 times of the LED dimension in the LED light emitting surface.

Next, the design example at the time of sealing the LED 11 and the 1st lens 21a with silicon (refractive index = 1.4) with respect to the light emitting diode illuminating device 10 using the light emitting diode illuminating member 70 is shown. Indicates.

                          d0 = 0.5 n1 = 1.4 ν1 = 50

r1 = ∞ d1 = 1.4 n1 = 1.5168 ν1 = 64.17

r2 = −2.1 d2 = 1

r3 = ∞ d3 = 5.6 n2 = 1.8467 v2 = 23.78

r4 = -5 d4 = 0.5 k4 = -0.67

The Monte Carlo simulation result on the same conditions as the light emitting diode illuminating device 10 of this design was 11 cd / mm <^2> of irradiation surface brightness, and 44% of irradiation efficiency. By sealing, the numerical aperture of the LED output light is 1.4 (= refractive index) times. This brings about the same effect as when the numerical aperture = 1, the LED size is 1.4 times, the area is double, and the brightness is 1/2. The effect of the light emitting diode illumination device 10 being halved, such as the brightness of the irradiation surface and the irradiation efficiency, is attributable to this effect. From this, it is important to arrange the LED 11 in the air for the high-brightness LED illuminating device.

The irradiation surface of the light emitting diode illuminating devices 10, 30, 50 of the 1st, 2nd, and 3rd embodiment of this invention can also be handled as a new light emitting surface. That is, it becomes a new light emitting surface which reduced the numerical aperture and increased the light emitting area, without lowering the luminance. For example, the irradiation surface of the light emitting diode illuminating devices 10, 30, and 50 may be imaged and used for a reflective display element.

10, 30, 50 light emitting diode lighting units
11 LED (Light Emitting Diode)
12 optical system
13 mixing rod
14, 15 screen
21a, 21b lens
31 tapered rod
51 compound parabolic mirror
70 Light Emitting Diodes
71 flat substrates

Claims (8)

A light emitting diode illumination device having a light emitting diode and an optical system provided to convert a numerical aperture of the emitted light of the light emitting diode,
When the representative dimension of the light emitting surface of the light emitting diode is L, the representative dimension of the optical system is Do, and the numerical aperture of the light irradiated from the device is NAout,
0.8L / NAout≤Do≤1.1L / NAout
Light emitting diode illumination device characterized in that the. The method of claim 1,
The optical system is composed of a lens having a positive refractive power,
The light emitting diode is disposed in or near the focal point of the optical system,
When the typical dimension Do of the optical system is the diameter of the lens and the focal length of the lens is f,
Do ≒ 2f ≒ L / NAout
Light emitting diode illumination device characterized in that the. The method of claim 1,
The light emitting diode is composed of a plurality, the light emitting surface is arranged on the same plane so as to emit light in the same direction, respectively,
The optical system is configured in plural and provided corresponding to each light emitting diode so as to convert the numerical aperture of the emitted light of each light emitting diode,
Representative dimensions of the light emitting surface of each light emitting diode are L, Iled is the spacing between neighboring light emitting diodes, Do is a representative dimension of each optical system, Io is the spacing between neighboring optical systems, and Io is the numerical aperture of light irradiated from the device. When set to NAout,
0.8 L / NAout≤Do≤1.1 L / NAout
Io≤Iled
Io≤Do
Light emitting diode illumination device characterized in that the. The method of claim 3,
Each optical system is composed of a lens having a positive refractive power,
Each light emitting diode is disposed in or near the focus of each optical system,
When the typical dimension Do of each optical system is the diameter of the lens and the focal length of the lens is f,
Do ≒ 2f ≒ L / NAout
Io = Iled≤Do
Light emitting diode illumination device characterized in that the. The method of claim 3,
Each optic consists of tapered rods,
Representative dimension Do of each optical system is made into the exit dimension of the said taper rod, space | interval Io between adjacent optical systems is made into the space | interval at the said taper rod exit, Din and the inlet dimension of the said taper rod are opened When the angle is φ and the interval between each light emitting diode and each optical system is t,
Do ≒ Din / NAout ≒ Io = Iled
φ <NAout / 10
L≤Din≤1.1L
0 <t≤0.2L
Light emitting diode illumination device characterized in that the. The method of claim 3,
Each optic consists of tapered rods,
When the representative dimension Do of each optical system is made into the exit dimension of the said taper rod, the space | interval Io between adjacent optical systems is made into the space | interval at the said taper rod exit, and the inlet dimension of the taper rod is set to Din,
Do ≒ Din / NAout ≒ Io <Iled
Light emitting diode illumination device characterized in that the. The method of claim 3,
Each optical system consists of a compound parabolic condenser
When the representative dimension Do of each optical system is the exit dimension of the compound parabolic light collector, and the inlet dimension Din of the compound parabolic light collector is set, and the interval between each light emitting diode and each optical system is t,
Do ≒ Din / NAout ≒ Io = Iled
L≤Din≤1.1L
0 <t≤0.2L
Light emitting diode illumination device characterized in that the. In the light emitting diode illumination member which comprises the light emitting diode illumination device as described in any one of Claims 3-7,
Each light emitting diode is densely arranged or squarely arranged at equal intervals on a plane at intervals satisfying 2L <Iled <10L so that each light emitting diode can emit light in the same direction, and in the light emitting direction of each light emitting diode for each light emitting diode. A light emitting diode illumination member, characterized in that each optical system is configured to be close to 0.4L.

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