JPWO2018225376A1 - Lighting unit - Google Patents

Abstract

(EN) A small illumination unit suitable for performing illumination such as not illuminating a certain area or forming characters or shapes by turning on and off a specific light source. An illumination unit including a plurality of light sources and an optical system that modulates light emitted from the light sources is provided. The optical system is arranged between a lens unit including a plurality of lenses and the light source and the lens unit. And a light distribution control multiplexing element, wherein the light distribution control multiplexing element has a tapered shape that widens from the light source side toward the lens unit side, and guides the emitted light emitted from the light source. A plurality of light guide portions and a flat plate portion arranged on the exit side of the light guide portion, and the light guide portion has an area of an incident surface on which light emitted from the light source in the light guide portion is incident. The area of the emission surface for emitting the incident light to the flat plate portion is set to 1.2 times or more and 2.5 times or less.

Description

  The present invention relates to a lighting unit, and more particularly, to a lighting unit that controls a light distribution of light emitted from a plurality of light sources to illuminate an object to be illuminated, and particularly to an indoor lighting device, a building lighting device, and a vehicle lighting device. The present invention relates to an illumination unit that can be applied to an imaging device such as a device, an enlarged projection device, or a microscope illumination device.

  2. Description of the Related Art In recent years, energy problems have been increasing on a global scale, and LED lighting devices using light-emitting diodes (LEDs), which are energy-saving and have a long life, as light sources have attracted attention and are actually used. In general, since the light emitted from the LED light source is a Lambertian light distribution, for example, when used for signboard illumination or a liquid crystal backlight, a lens or a diffusion plate is used to illuminate the illumination range with uniform brightness. Are often used. When a lens or the like is used, it is necessary to arrange the light source and the lens separately in order to convert the light distribution characteristic by refraction of the lens system. In order to increase the brightness, it is necessary to increase the brightness (F number) of the optical system to a value close to the limit value F0.5 in the air, so that it is very difficult to manufacture the optical system from the viewpoint of workability and performance. Becomes

  On the other hand, when it is desired to irradiate a stronger and wider area, a method using a substrate on which a plurality of LED light sources are arranged and a lens for condensing or collimating light emitted from each LED has been adopted. When using such a light source, by turning off a specific LED chip among a plurality of light sources, no light is emitted in a specific direction, or by turning on a specific LED chip to imitate characters or shapes. It is also possible to illuminate light.

  For example, Patent Literature 1 discloses an illumination device that illuminates illumination light emitted from a plurality of light sources arranged in a high density in a plane shape to an object to be illuminated in a plane shape using an optical unit. Further, Patent Documents 2 and 3 disclose a configuration in which a tapered rod array is used in order to make uniform the illuminance and narrow the light distribution angle while increasing the use efficiency of light emitted from an LED or a secondary light source.

JP 2002-268001 A JP 2007-288169 A JP 2008-70769 A

  Generally, when illuminating light emitted from a light source is condensed or collimated by an optical means, the light intensity distribution on the irradiation surface is projected as an image with the shape of the light source as it is. In other words, when using multiple light sources, it is difficult to completely eliminate the gap between the light sources due to physical restrictions, even if they are arranged at high density. In the case of the arrangement, since the gap does not emit light, a grid-like pattern may be generated in the light intensity distribution on the irradiation surface. This can be a fatal problem for some lighting devices.

  In Patent Document 1, the light source is set not at the best focus position of the optical means but at a position slightly away from the best focus position, and the image of the light source is defocused to adjust the intensity distribution on the irradiation surface, thereby blurring the edge. Thereby, the emitted light of the adjacent light source is superimposed to make the irradiation intensity distribution uniform. However, such a defocusing technique means that the intensity of the light emitted from each light source is reduced on the irradiation surface and the irradiation range is widened (the base of the intensity profile is widened). Can reduce grid-like light and shade to some extent by superimposing multiple light sources.However, when implementing an illumination method that does not illuminate a specific area or imitate characters or shapes, such a method is used May be blurred.

  On the other hand, in Patent Documents 2 and 3, the use efficiency of light from a light source is increased by using a tapered rod array, and the illuminance distribution of emitted light guided by the tapered rod array is made uniform and the light distribution angle is reduced. Techniques are disclosed. In this case, in order to narrow the light distribution angle of the outgoing light, it is necessary to increase the area ratio between the incident side and the outgoing side of the tapered rod and make the length of the rod sufficiently long. Further, when a character or a shape is formed by turning on and off a specific LED by using a plurality of LEDs as a light source, it is necessary to set a small irradiation range (irradiation angle) of one LED. In addition, the focal length of the projection optical system is inevitably increased, and if the length of the tapered rod is taken into consideration, the projection optical system may become extremely large.

  The present invention has been made in view of the above-described problems of the background art, and allows light from a plurality of light sources arranged at high density to be projected onto an irradiation surface with high efficiency at a uniform and high intensity. It is an object of the present invention to provide a small-sized lighting unit suitable for performing lighting such as not illuminating a certain area or forming characters or shapes by turning on and off a light source.

In order to achieve at least one of the above objects, a lighting unit reflecting one aspect of the present invention is a lighting unit having a plurality of light sources and an optical system that modulates light emitted from the light sources,
The optical system has a lens unit including a plurality of lenses, and a light distribution control multiplexing element disposed between the light source and the lens unit,
The light distribution control multiplexing element has a plurality of light guide portions that have a tapered shape that expands from the light source side toward the lens unit side and guide light emitted from the light source, and an emission side of the light guide portion. A light emitting portion that emits light incident on the light guide portion to the flat plate portion with respect to an area of an incident surface of the light guide portion on which light emitted from the light source is incident. The area of the surface is set to be 1.2 times or more and 2.5 times or less.

  According to the present invention, light from a plurality of light sources arranged at high density can be projected onto an irradiation surface with high efficiency and high intensity, and a specific light source is turned on and off to illuminate a certain area. It is possible to provide a small-sized lighting unit suitable for performing lighting such as forming no characters or characters or shapes.

It is a schematic diagram of the lighting unit 10 according to the present embodiment. It is the perspective view which looked at the light distribution control multiplexing element 30 from the incident surface side. It is a schematic diagram which shows one LED chip and the light distribution control multiplexing element 30. It is sectional drawing of a light source and a light distribution control multiplexing element. FIG. 3 is a cross-sectional view of the lens unit according to the first embodiment. FIG. 3 is an aberration diagram (spherical aberration (a), astigmatism (b), and distortion (c)) of Example 1. It is a figure which shows the light distribution characteristic (Lambertian light distribution) without a light distribution control multiplexing element. FIG. 3 is a diagram illustrating light distribution characteristics after passing through a light distribution control multiplexing element according to the first embodiment. It is a figure which shows the state which controlled ON / OFF of each segment so that 8 might be drawn and illuminated only through a lens unit. FIG. 4 is a diagram illustrating a state in which light emitted from LED arrays having the same arrangement is irradiated through the light distribution control multiplexing element and the lens unit according to the first embodiment. FIG. 9 is a sectional view of a lens unit according to a second embodiment. FIG. 9 is an aberration diagram (spherical aberration (a), astigmatism (b), and distortion (c)) of Example 2. It is a figure which shows the light distribution characteristic (Lambertian light distribution) without a light distribution control multiplexing element. FIG. 9 is a diagram illustrating light distribution characteristics after passing through a light distribution control multiplexing element according to a second embodiment. It is a figure which shows the state which controlled ON / OFF of each segment so that 8 might be drawn and illuminated only through a lens unit. FIG. 9 is a diagram illustrating a state in which light emitted from an LED array having the same arrangement is irradiated through the light distribution control multiplexing element and the lens unit according to the second embodiment. FIG. 13 is a sectional view of a lens unit according to a third embodiment. FIG. 9 is an aberration diagram (spherical aberration (a), astigmatism (b), and distortion (c)) of Example 3. It is a figure which shows the light distribution characteristic (Lambertian light distribution) without a light distribution control multiplexing element. FIG. 14 is a diagram illustrating light distribution characteristics after passing through a light distribution control multiplexing element according to a third embodiment. It is a figure which shows the state which controlled ON / OFF of each segment so that 8 might be drawn and illuminated only through a lens unit. FIG. 13 is a diagram illustrating a state in which light emitted from LED arrays having the same arrangement is irradiated through the light distribution control multiplexing element and the lens unit according to the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a lighting unit 10 according to the present embodiment. As shown in FIG. 1, a lighting unit 10 includes a lens unit 20 having a plurality of lenses, a light distribution control multiplexing element 30, and a light source in which a plurality of LED chips are two-dimensionally arranged (this is referred to as an LED array). 40. However, the LED chips may be arranged on a straight line. The distance between the LED chips is preferably 150 μm or less. It is preferable that the LED chips be independently controllable for lighting, since a desired illumination shape can be formed. The lens unit 20 and the light distribution control multiplexing element 30 constitute an optical system. Note that “modulation” refers to an action of changing the direction in which light travels, for example, an action of condensing, collimating, and diverging.

  The lens unit 20 is composed of a positive lens L1, a negative lens L2, a positive lens L3, a positive lens L4, and a lens barrel 21 holding these in order from the emission side. It is sufficient that the lens unit 20 has three or more lenses, and it is preferable that at least one of these lenses is a plastic aspheric lens. In particular, the plastic aspherical lens is preferably formed from a material having high heat resistance such as acrylic or polycarbonate. Further, it is preferable that the F-number of the lens unit 20 is 0.58 or more and 0.80 or less. As a result, the amount of light taken into the lens unit 20 increases, so that the light use efficiency can be increased. In particular, it is preferable that the lens closest to the light source has a high curvature. Thereby, the light from the light source can be secured as much as possible.

If the F number of the lens unit 20 is F, its focal length is f, and its maximum effective diameter is φmax, it is preferable that the following expression (3) is satisfied. If the value of the expression (3) is lower than the lower limit, a desired F-number cannot be secured, and if the value of the expression (3) exceeds the upper limit, the size becomes large in the radial direction.
1.0 ≦ φmax / (f / F) ≦ 1.2 (3)

  FIG. 2 is a perspective view of the light distribution control multiplexing element 30 as viewed from the incident surface side. The light distribution control multiplexing element 30 is integrally formed of silicone which is resistant to heat and is easy to process, or glass which is resistant to heat and has a small linear expansion and is superior in performance. Has a shape in which the light guide portions 32 are two-dimensionally arranged. One light guide section 32 is arranged to face one square LED chip (not shown), and spreads from a light source (front side in FIG. 2) side to a lens unit (back side in FIG. 2) side. It has a tapered shape (here, truncated pyramid shape). By employing a tapered shape, the light distribution can be narrowed, which is effective in improving the light use efficiency. In addition, since the light taken into each light guide portion 32 from the incident surface 32a can be multiplexed on the output surface 32b, for example, the grid-like light and dark can be eliminated.

  Although not shown, one light guide 32 may be arranged to face a plurality of LED chips. By taking in the light emitted from the plurality of LED chips into one light guide section 32 and multiplexing the light, the brightness of the non-light emitting section existing between the plurality of LED chips can be substantially eliminated, and the LED chip It is possible to increase the luminous flux by combining a plurality of.

  The light guide section 32 has a square incident surface 32a on the light source side, a square exit surface 32b on the lens unit side, and a side surface 32c. The emission surface 32b is a boundary surface with the flat plate portion 31 and is a plane virtually formed on the inner surface of the light distribution control multiplexing element 30. Here, the area of the exit surface 32b is set to be 1.2 times or more and 2.5 times or less with respect to the area of the incident surface 32a which is a flat surface. More preferably, it is set to be 1.2 times or more and 2.0 times or less, and in this case, a smaller illumination unit can be provided.

  In addition, the light guide part and the flat part of the light distribution control multiplexing element may be separately manufactured and then joined together, or the light guide part and the flat part may be integrally formed using a mold or the like. Is also good. Of course, a manufacturing method of cutting and shaping flat glass subjected to physical and chemical processing may be used. Lenses or prisms may be formed in an array on the emission surface of the flat plate portion.

The incident surface 32a and the outgoing surface 32b of the light guide 32 may be substantially square. Referring to FIG. 4, if the length of the light guide portion 32 in the light guide direction is H, the size of one side of the incident surface 32a is D1, and the size of one side of the output surface 32b is D2, the following formula is satisfied. Is desirable. If the value of the expression (1) is lower than the lower limit, the light distribution cannot be sufficiently narrowed, and a large loss may be generated in the light incident on the lens unit 20, and the value of the expression (1) exceeds the upper limit. This is because there is a possibility that the light guide region becomes too long and the workability deteriorates.
4 ≦ H / (D2−D1) ≦ 14 (1)
More preferably, the following expression (1 ′) is satisfied. In this case, a smaller illumination unit can be provided.
4 ≦ H / (D2−D1) ≦ 10 (1 ′)

It is preferable that the refractive index nd of the material of the light distribution control multiplexing element satisfies the following expression.
1.4 <nd <1.8 (2)
Further, it is preferable to satisfy the following expression because a smaller illumination unit can be obtained.
1.4 <nd <1.55 (2 ′)
Examples of the glass satisfying the range of (2 ′) include BK7 and quartz glass.

  The operation of the light distribution control multiplexing element 30 will be described. FIG. 3 is a schematic diagram showing one LED chip and the light distribution control multiplexing element 30. The emission surface 41a of the LED chip 41 of the light source is arranged close to the incidence surface 32a of the light guide 32 of the light distribution control multiplexing device 30. The “proximity” is, for example, a distance of 1/5 or less, preferably 1/10 or less of the length of one side of the LED chip 41. The light emitted from the light source can be efficiently taken into the element by making the shape of the incident surface 32a similar to and larger than the shape of the exit surface 41a.

  Light is emitted from the emission surface 41a of the LED chip 41 in a so-called Lambertian shape. Here, the emission light LB emitted in a direction inclined at a shallow angle with respect to the emission surface 41a when there is no light guide portion 32 is indicated by a dotted line. In such a case, the emitted light LB emitted at a shallow angle travels linearly and laterally, and is incident on a lens unit (not shown) disposed above the light distribution control multiplexing element 30 in FIG. Therefore, the light use efficiency is reduced.

  On the other hand, according to the present embodiment, the outgoing light LB emitted in the direction inclined with respect to the outgoing surface 41a is refracted by the incident surface 32a of the light guide 32 and is reflected by the light guide as shown by the dashed line. The light enters the inside 32, and is further totally reflected by the side surface 32c, exits from the exit surface 32b, passes through the flat plate portion 31, and enters the lens unit. As a result, the light distribution characteristics can be changed to increase the light use efficiency.

  In addition, as shown by a two-dot chain line in FIG. 3, the incident surface 32a may be made to be a convex surface and abut on the emission surface 41a of the LED chip 41.

  As described above, a technique such as a conventional technique for intentionally setting a focus to an out-of-focus state is effective for uniformizing the intensity distribution, but does not illuminate a specific area or forms a character or shape. Not legal. If a tapered rod array having a large area ratio between the incident side and the exit side is used, the optical system becomes large. In contrast, in the present embodiment, since the light distribution control multiplexing element 30 is inserted between the lens unit 20 and the light source 40, the light source 40 has an effect of increasing the size of the light source 40, so that the light source 40 can be made out of focus. At least, it is possible to make the illuminance distribution uniform on the irradiation surface, and because it is not out of focus, it is possible to illuminate a specific area without illuminating it or to form characters or shapes. Furthermore, the light from the light source is efficiently extracted by arranging the light guide 32 of the light distribution control multiplexing element 30 close to the light source 40, and the light is reflected by the total reflection on the tapered side surface 32c of the light guide 32. Can be made closer to the direction parallel to the optical axis, and the light emitted from the light distribution control multiplexing element 30 can be efficiently incident on the lens unit 20 by narrowing the light distribution. Together with these effects, a very efficient and compact lighting unit can be realized.

  Hereinafter, an example of a lighting unit suitable for the present embodiment will be described. FIG. 4 is a cross-sectional view of the light source and the light distribution control multiplexing device, and shows the dimensions of each part. In FIG. 4, the length of one side of the light source 41 is D3, the length of one side of the incident surface 32a of the light guide 32 is D1, and the height of the light guide 32 (incident surface 32a to emission surface 32b) is H. And the pitch (distance between optical axes) of the light guides 32 is P.

  In the following examples, the surface on which the aspheric coefficient is described is a surface having an aspheric shape, and the shape of the aspheric surface has the vertex of the surface as the origin, the X axis in the optical axis direction, and the optical axis. The height in the vertical direction is represented by h, and is represented by the following “Equation 1”.

ただし、
Ａｉ：ｉ次の非球面係数
Ｒ ：曲率半径
Ｋ ：円錐定数

However,
Ai: i-th order aspherical coefficient R: radius of curvature K: conic constant

(Example 1)
Referring to FIG. 4, the dimensional relationship between the light source and the light distribution control multiplexing element made of silicone is as follows.
D3: 0.4mm
D2: 0.5 mm
D1: 0.44 mm
H: 0.5 mm
P: 0.5mm
Value of equation (1): 8.3
Area ratio between output surface and input surface: 1.29

Hereinafter, the lens unit of the first embodiment will be described. Table 1 shows lens data of Example 1. In the following (including the lens data in the table), a power of 10 (for example, 2.5 × 10 ^-02 ) is represented by E (for example, 2.5E-02). F is a number and f is a focal length.

[Table 1]
Example 1
F: 0.60
f: 28.6mm
Value of equation (3): 1.0

Surface number Radius of curvature Interval Refractive index (OBJ) 0 ∞ ∞
1 27.367 15.95 1.4884
2 189.028 8.00
3 -15.975 7.00 1.5788
4 31.428 14.26
(Aperture) 5 ∞ -8.73
6 11.322 19.00 1.4884
7 792.558 4.94
8 13.129 18.00 1.4884
9 77.247 4.58

Aspheric coefficient
One surface
R = 27.367
K = 0.0825
A4 = 2.76E-06
A6 = -3.87E-08
A8 = 1.38E-10
A10 = -4.50E-13
A12 = 6.33E-16
A14 = -4.18E-19

2 sides
R = 189.028
K = -40.0000
A4 = 1.19E-05
A6 = -1.17E-07
A8 = 2.37E-10
A10 = -9.16E-14
A12 = -2.78E-16
A14 = 2.56E-19

3 sides
R = -15.975
K = -1.4007
A4 = 7.25E-05
A6 = -2.53E-07
A8 = 7.01E-10
A10 = -1.30E-12
A12 = 1.33E-15
A14 = -5.71E-19

4 sides
R = 31.428
K = -40.0000
A4 = -3.72E-06
A6 = 2.37E-07
A8 = -6.98E-10
A10 = 4.04E-13
A12 = 6.11E-16
A14 = -6.37E-19

6 faces
R = 11.322
K = -3.4716
A4 = 5.66E-05
A6 = -3.76E-07
A8 = 2.22E-09
A10 = -7.91E-12
A12 = 1.53E-14
A14 = -1.23E-17

7 faces
R = 792.558
K = -40.0000
A4 = -4.32E-05
A6 = 2.78E-07
A8 = -1.41E-09
A10 = 5.56E-12
A12 = -1.14E-14
A14 = 8.47E-18

8 faces
R = 13.129
K = -0.8460
A4 = -2.61E-05
A6 = 1.84E-07
A8 = -2.58E-10
A10 = -9.31E-14
A12 = 0.00E + 00
A14 = 0.00E + 00

9 faces
R = 77.247
K = 0.0000
A4 = -4.16E-05
A6 = -9.55E-07
A8 = 1.04E-08
A10 = -2.93E-11
A12 = 0.00E + 00
A14 = 0.00E + 00

  FIG. 5 is a sectional view of the lens unit according to the first embodiment. In the figure, the lens unit of Example 1 has a positive lens L1, a negative lens L2, a stop S, a positive lens L3, and a positive lens L4 in order from the emission side. FIG. 6 is an aberration diagram of Example 1 (spherical aberration (a), astigmatism (b), and distortion (c)). Here, in the spherical aberration diagram, the amounts of spherical aberration with respect to the c-line, d-line, and g-line are respectively shown. In the astigmatism diagram, the solid line S represents a sagittal surface, and the dotted line M represents a meridional surface.

  FIG. 7 is a diagram showing light distribution characteristics without a light distribution control multiplexing element, and FIG. 8 is a light distribution characteristic (Lambertian light distribution) after passing through the light distribution control multiplexing element in the first embodiment. Are shown with the ordinate representing the luminous intensity and the abscissa representing the angle. When the lens unit transmittance is 88%, the light use efficiency is 57.9% in the comparative example of FIG. 7, and the light use efficiency is 70.2% in Example 1 of FIG. You can see that it is doing.

  FIG. 9 shows a state in which the LED array is controlled to ON / OFF for each segment so as to draw 8, and is illuminated only through the lens unit. FIG. 10 shows light emitted from the LED array having the same arrangement. FIG. 4 is a diagram illustrating a state where light is emitted through a light distribution control multiplexing element and a lens unit according to the first embodiment. Comparing the comparative example of FIG. 9 with the example 1 of FIG. 10, it can be seen that the black lines between the LED chips are clearly visible in FIG. 9, but are not visible at all in FIG.

(Example 2)
Referring to FIG. 4, the dimensional relationship between the light source and the light distribution control multiplexing element made of glass is as follows.
D3: 0.25 mm
D2: 0.3mm
D1: 0.26 mm
H: 0.3mm
P: 0.3mm
Value of equation (1): 7.5
The area ratio between the exit surface and the entrance surface is 1.33.

  Hereinafter, the lens unit according to the second embodiment will be described. Table 2 shows lens data of Example 2.

[Table 2]
Example 2
F 0.65
f 19.5mm
Value of equation (3): 1.0
Surface number Radius of curvature Interval Refractive index (OBJ) 0 ∞ ∞
1 17.428 9.60 1.4884
2 96.833 5.70
3 -10.995 4.50 1.5788
4 21.051 8.23
(Aperture) 5 ∞ -4.70
6 7.745 12.40 1.4884
7 ∞ 2.70
8 8.831 13.00 1.4884
9 24.848 2.57

Aspheric coefficient

One surface
R = 17.428
K = 0.1130
A4 = -4.26E-06
A6 = -2.04E-07
A8 = 1.26E-09
A10 = -1.43E-11
A12 = 5.53E-14
A14 = -1.09E-16

2 sides
R = 96.833
K = 27.9955
A4 = 1.50E-05
A6 = -7.17E-07
A8 = 3.63E-09
A10 = -4.91E-12
A12 = -2.43E-14
A14 = 6.42E-17

3 sides
R = -10.995
K = -1.6093
A4 = 2.30E-04
A6 = -1.72E-06
A8 = 1.02E-08
A10 = -4.15E-11
A12 = 9.18E-14
A14 = -7.85E-17

4 sides
R = 21.051
K = -40.0000
A4 = 2.18E-05
A6 = 1.41E-06
A8 = -1.09E-08
A10 = 1.41E-11
A12 = 5.43E-14
A14 = -1.18E-16

6 faces
R = 7.745
K = -3.6110
A4 = 1.92E-04
A6 = -2.66E-06
A8 = 3.20E-08
A10 = -2.43E-10
A12 = 1.06E-12
A14 = -2.02E-15

7 faces
R = ∞
K = 0.0000
A4 = -1.44E-04
A6 = 1.96E-06
A8 = -2.01E-08
A10 = 1.69E-10
A12 = -7.91E-13
A14 = 1.36E-15

8 faces
R = 8.831
K = -1.1051
A4 = -3.84E-05
A6 = 1.44E-06
A8 = -7.66E-09
A10 = 2.50E-11
A12 = 0.00E + 00
A14 = 0.00E + 00

9 faces
R = 24.848
K = 0.0000
A4 = -5.93E-04
A6 = -2.30E-06
A8 = 1.58E-07
A10 = -1.01E-09
A12 = 0.00E + 00
A14 = 0.00E + 00

  FIG. 11 is a sectional view of a lens unit according to the second embodiment. In the figure, the lens unit of Example 2 has a positive lens L1, a negative lens L2, a stop S, a positive lens L3, and a positive lens L4 in order from the emission side. FIG. 12 is an aberration diagram of Example 2 (spherical aberration (a), astigmatism (b), and distortion (c)). Here, in the spherical aberration diagram, the amounts of spherical aberration with respect to the c-line, d-line, and g-line are respectively shown. In the astigmatism diagram, the solid line S represents a sagittal surface, and the dotted line M represents a meridional surface.

  FIG. 13 is a diagram illustrating light distribution characteristics (Lambertian light distribution) without a light distribution control multiplexing element, and FIG. 14 is a light distribution characteristic after passing through the light distribution control multiplexing element in the second embodiment. Are shown with the ordinate representing the luminous intensity and the abscissa representing the angle. When the transmittance of the lens unit is 88%, the light use efficiency is 51.1% in the comparative example of FIG. 13, and the light use efficiency is 63.1% in Example 2 of FIG. You can see that it is doing.

  FIG. 15 shows a state in which the LED array is turned ON / OFF for each segment so as to draw 8 and is illuminated only through the lens unit. FIG. 16 shows light emitted from the LED array having the same arrangement. FIG. 8 is a diagram illustrating a state where light is emitted through a light distribution control multiplexing element and a lens unit according to a second embodiment. A comparison between the comparative example of FIG. 15 and Example 2 of FIG. 16 shows that the black line between the LED chips is clearly visible in FIG. 15, but is not visible at all in FIG.

(Example 3)
Referring to FIG. 4, the dimensional relationship between the light source and the light distribution control multiplexing element made of glass is as follows.
D3: 0.25 mm
D2: 0.35 mm
D1: 0.26 mm
H: 0.4mm
P: 0.35mm
Value of equation (1): 4.4
The area ratio between the exit surface and the entrance surface: 1.81

  Hereinafter, the lens unit of the third embodiment will be described. Table 3 shows the lens data of the third embodiment.

[Table 3]
Example 3
F 0.70
f 21.0mm
Value of equation (3): 1.0
Surface number Radius of curvature Interval Refractive index (OBJ) 0 ∞ ∞
1 16.440 10.90 1.4884
2 -749.941 3.85
3 -12.165 4.90 1.5788
4 16.543 6.32
(Aperture) 5 ∞ -2.88
6 7.754 13.50 1.4884
7 422.545 1.93
8 8.917 12.30 1.4884
9 20.561 2.00

Aspheric coefficient

One surface
R = 16.440
K = -0.2898
A4 = 1.96E-06
A6 = -5.88E-08
A8 = 9.15E-10
A10 = -8.53E-12
A12 = 1.82E-14
A14 = -1.42E-17

2 sides
R = -749.941
K = 40.0000
A4 = 1.69E-05
A6 = -4.76E-07
A8 = 2.11E-09
A10 = -2.17E-12
A12 = -9.81E-15
A14 = 4.46E-17

3 sides
R = -12.165
K = -1.7601
A4 = 1.87E-04
A6 = -1.21E-06
A8 = 6.04E-09
A10 = -2.04E-11
A12 = 4.45E-14
A14 = -2.16E-17

4 sides
R = 16.543
K = -20.3623
A4 = 7.05E-05
A6 = 1.16E-06
A8 = -5.98E-09
A10 = -3.21E-12
A12 = -2.80E-14
A14 = 2.74E-16

6 faces
R = 7.754
K = -3.4020
A4 = 1.75E-04
A6 = -1.86E-06
A8 = 1.80E-08
A10 = -1.19E-10
A12 = 5.50E-13
A14 = -1.51E-15

7 faces
R = 422.545
K = -22.2388
A4 = -8.50E-05
A6 = -6.08E-07
A8 = 3.45E-08
A10 = -4.91E-10
A12 = 3.24E-12
A14 = -8.83E-15

8 faces
R = 8.917
K = -0.9086
A4 = 8.54E-06
A6 = -3.63E-07
A8 = 2.40E-08
A10 = -1.56E-10
A12 = 0.00E + 00
A14 = 0.00E + 00

9 faces
R = 20.561
K = 0.0000
A4 = -4.63E-04
A6 = -3.89E-06
A8 = 1.89E-07
A10 = -1.75E-09
A12 = 0.00E + 00
A14 = 0.00E + 00

  FIG. 17 is a sectional view of a lens unit according to the third embodiment. In the figure, the lens unit of Example 3 has a positive lens L1, a negative lens L2, a stop S, a positive lens L3, and a positive lens L4 in order from the emission side. FIG. 18 is an aberration diagram of Example 3 (spherical aberration (a), astigmatism (b), and distortion (c)). Here, in the spherical aberration diagram, the amounts of spherical aberration with respect to the c-line, d-line, and g-line are respectively shown. In the astigmatism diagram, the solid line S represents a sagittal surface, and the dotted line M represents a meridional surface.

  FIG. 19 is a diagram illustrating light distribution characteristics (Lambertian light distribution) without a light distribution control multiplexing element. FIG. 20 is a diagram illustrating light distribution characteristics after passing through the light distribution control multiplexing element in the third embodiment. Are shown with the ordinate representing the luminous intensity and the abscissa representing the angle. When the transmittance of the lens unit is 88%, the light use efficiency is 51.1% in the comparative example of FIG. 19, and the light use efficiency is 68.8% in Example 3 of FIG. 20, which improves the efficiency. You can see that it is doing.

  FIG. 21 shows a state in which the LED array is controlled to be ON / OFF for each segment so as to draw 8, and is irradiated only through the lens unit. FIG. 22 shows the light emitted from the LED array having the same arrangement. FIG. 14 is a diagram illustrating a state where light is emitted through a light distribution control multiplexing element and a lens unit according to a third embodiment. A comparison between the comparative example of FIG. 21 and Example 3 of FIG. 22 shows that the black line between the LED chips is clearly visible in FIG. 21, but is not visible at all in FIG.

  The present invention is not limited to the embodiments and examples described in the specification, and includes other embodiments, examples, and modified examples. It will be apparent to those skilled in the art from technical ideas. The description and embodiments of the specification are for the purpose of illustration only, and the scope of the present invention is indicated by the following claims. For example, the imaging lens of the present invention is not limited to a five-lens configuration or a six-lens configuration, and may be composed of seven or more lenses.

DESCRIPTION OF SYMBOLS 10 Illumination unit 20 Lens unit 21 Lens barrel 30 Light distribution control multiplexing element 31 Flat plate part 32 Light guide part 32a Incident surface 32b Output surface 32c Side surface 40 Light source 41 LED chip 41a Output surface L1 Positive lens L2 Negative lens L3 Positive lens L4 Positive lens

Claims (16)

In a lighting unit having a plurality of light sources and an optical system that modulates light emitted from the light sources,
The optical system has a lens unit including a plurality of lenses, and a light distribution control multiplexing element disposed between the light source and the lens unit,
The light distribution control multiplexing element has a plurality of light guide portions that have a tapered shape that expands from the light source side toward the lens unit side and guide light emitted from the light source, and an emission side of the light guide portion. A light emitting portion that emits light incident on the light guide portion to the flat plate portion with respect to an area of an incident surface of the light guide portion on which light emitted from the light source is incident. A lighting unit whose surface area is set to be 1.2 times or more and 2.5 times or less.   2. The illumination unit according to claim 1, wherein in the light distribution control multiplexing element, an incident surface of each light guide region is similar to a shape of an emission surface of the light source, and is larger than an emission surface of the light source.   The illumination according to claim 1, wherein the light guide of the light distribution control multiplexing element has a truncated quadrangular pyramid shape, and an incident surface of each light guide is arranged close to an emission surface of each light source. unit.   The light guide part of the said light distribution control multiplexing element has a quadrangular pyramid shape, The incident surface of each light guide part is arrange | positioned close to the emission surface of several said light sources. Lighting unit. The entrance surface and the exit surface of the light guide are substantially square, the length of the light guide in the light guide direction is H, the size of one side of the entrance surface is D1, and the size of one side of the exit surface is The lighting unit according to claim 3 or 4, wherein D2 satisfies the following expression.
4 ≦ H / (D2−D1) ≦ 14 (1)   The lighting unit according to claim 1, wherein an incident surface of the light guide is convex, and is in contact with an emission surface of the light source.   The illumination unit according to claim 1, wherein a lens or a prism is formed in an array on an emission surface of the flat plate portion.   The lighting unit according to claim 1, wherein the light distribution control multiplexing element is made of silicone.   The lighting unit according to claim 1, wherein the light distribution control multiplexing element is made of glass. The lighting unit according to claim 9, wherein a refractive index nd of a material of the light distribution control multiplexing element satisfies the following expression: 1.4 <nd <1.8 (2).   The lighting unit according to any one of claims 1 to 10, wherein the lens unit of the optical system includes three or more lenses, and an F number of the lens unit is 0.58 or more and 0.80 or less. The illumination unit according to any one of claims 1 to 11, wherein an F number of the lens unit is F, a focal length thereof is f, and a maximum effective diameter thereof is φmax.
1.0 ≦ φmax / (f / F) ≦ 1.2 (3)   The lighting unit according to claim 1, wherein the lens unit includes at least one plastic aspheric lens.   The lighting unit according to any one of claims 1 to 13, wherein the light source is an LED array arranged in a straight line.   The lighting unit according to claim 1, wherein the light source is a two-dimensionally arranged LED array.   The lighting unit according to claim 1, wherein an interval between the plurality of light sources is 150 μm or less.

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