JP3073246U - LED lighting device - Google Patents

Abstract

(57) [Summary] [Problem] To be able to adjust the brightness contrast in both vertical and horizontal directions, prevent dust from accumulating, easily maintain clean light, and beautify the vision of images to be excellent. Provide an LED lighting device with a lighting effect. SOLUTION: A substrate (3) and a lamp cap (4) are sequentially provided in a lamp case (2), and a lamp cap of the substrate (3) is provided.
A number of LEDs (32) are mounted on the side opposite to (4), and a plurality of lens units are provided on the entrance surface (41) of the lamp cap (4).
(5), each lens unit (5) is provided with a plurality of lens means (50) having different elevation angles along the vertical direction on the side facing the LED (32) and maintaining the same or different curvature in the horizontal direction. The lens means (50) allows adjustment of the vertical luminance contrast and the horizontal luminance contrast when the incident light is projected from the exit surface (42) of the lamp cap (4).

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an LED lighting device, and in particular, can adjust the brightness contrast in both the vertical and horizontal directions, can prevent dust from being accumulated, easily maintain clean light, and beautify image vision. The present invention relates to an LED lighting device having an excellent lighting effect.

[0002]

[Prior art]

 Conventionally, most traffic signal lights and high-altitude lighting devices on the street use incandescent bulbs that emit wavelengths in the entire visible range.However, incandescent bulbs are frequently used because they not only consume a large amount of electricity but also are incandescent and easily disconnected. In addition, the illumination range of the incandescent light bulb is evenly distributed in three dimensions around the light bulb, and a concave reflector and a convex lens are provided behind and in front of the light bulb, respectively. However, for example, only the lighting within the effective visual range of the vehicle driver or pedestrian in the lower half of the light axis of the road surface or the light beam for the purpose, such as the headlight of the vehicle, needs to be scattered above the upper half. The use of energy is inefficient because of the wasted light.

On the other hand, an LED (light emitting diode) emits light at a single wavelength in almost a specific direction, and has advantages such as low power consumption and long life. If this is used, the cost and frequency of maintenance can be reduced by saving more than 80% of electricity, and at the same time, direct radiation is achieved by the presence of front and rear lenses and reflectors like conventional signal lights and headlights. This avoids the illusion of lighting as if reflecting sunlight.

[0004] However, since the luminous intensity of the LED is relatively small, most of the LED light is conventionally used only for short-distance lighting (for example, panel display or indoor lighting), and if used for outdoor lighting. Must first solve the problems of requiring a long projection distance, many strong interfering light rays in the surrounding area, and limited human visibility.

In recent years, in order to make full use of the excellent characteristics of the LED itself, research and improvements have been made on various aspects such as the performance and efficiency of the LED. As a result, the idea of using the LED as a light source for outdoor lighting devices has never been realized. Rather than being practical, it is, in fact, gradually becoming universal. However, LEDs are still inherently limited in terms of launch angle and intensity (the luminous intensity of the LEDs is relatively small and the irradiation angle is also narrow), so when using LEDs as light sources for traffic signal lighting devices. Must optically restrict the light emitted from the LED to a specific angle or range, for example, the inspection standards or traffic standards set by the Institute of Transport Engineers (ITE) for traffic signal lighting equipment. Various other regulations must be achieved. Therefore, various lamp cap structures were finally born in order to make LED traffic signal lighting devices more efficient in terms of energy use and more compliant with ITE inspection requirements or other regulations.

FIGS. 8 and 9 show US Pat. No. 5,174,649 to Alston, in which a number of hyperboloidally shaped lens elements 101 are regularly arranged on an entrance surface 100 inside a lamp cap 10. Then, a number of projecting small facets 103 are formed on the exit surface 102 on the opposite side, the LED 104 is positioned at the focal point of each hyperboloid, and the light beam projected from the LED 104 is reflected by the hyperboloid lens element 101. The light beam 105 is refracted and becomes a parallel light beam 105, which is further radiated from the small face 103 of the exit surface 102, and is distributed to each fine area in front to form a specific light intensity distribution. I do. However, since the light emitting surface 102 of the lamp cap 10 is provided with a small surface 103 having a large number of small projections, if used for outdoor lighting, dust and grease will adhere thereto, and as a result The illumination light is affected by the uneven distribution of light rays, resulting in a loss of light energy.

[0007] FIG. 10 shows US Pat. No. 5,343,330 to Hoffman et al. In which a number of truncated cones, each of which has a different slope from a cylindrical insert, are continuously extended in a lighting device. A three-dimensional lens 11 is provided, and a cylindrical storage hole 110 is recessed in each lens 11 and a conical LED is inserted therein. The light beam first performs primary refraction and total reflection in order on a refracting surface 111 having the same conical shape in the lens 11 and a first reflecting surface 112 having a conical shape opposite to the above, and further from the lens 11. When the light is projected toward the front end, the second refraction occurs on the second refraction surface 113, which is the end surface of the truncated cone, so that the direction of the light beam is partially directed forward and partially directed forward. Change to However, since the LED is inserted into the lens 11 and causes the light beam to perform second-order refraction and total reflection by the lens 11, difficulty in geometrical arrangement of the lens is high. In addition, welding and connection must be performed without being able to be connected on the printed circuit board.In particular, the total number of LEDs required for the entire lighting system is extremely large (generally, 100 LEDs are overloaded), so assembly and maintenance work is complicated. Inconvenient.

[0008] FIGS. 11 and 12 show US Pat. No. 5,833,355 to You et al., Which extends parallel to a number of horizontal directions on a flat plate as a refractive lens in front of an LED light source. The ridge-shaped prisms 12 are formed corresponding to the LEDs arranged in each horizontal row, and each prism 12 is gently connected to a vertical surface 121 formed by a plane substantially perpendicular to the flat plate in the vertical width direction. An upper half 120 consisting of an ascending curved surface 122 and a lower half 123 consisting of an area 124 that becomes a flat surface from a loose curved surface following the curved surface 122 and an undulating wavy surface extending the entire length below the area 124. It is configured to refract the upward part of the light beam emitted from the LED in a divergent conical shape downward or horizontally, and to scatter the light beams of the part horizontal and downward parts evenly to the left and right. However, due to the peculiarity of the geometric shape of the ridge-shaped prism 12, the purpose of use is limited and the usable applications are narrow and cannot be widely used. Moreover, since the upper half 120 of the prism 12 refracts only the transmitted light in the vertical direction, the image viewed through such a lens is unnaturally deformed.

[0009]

[Problems to be solved by the invention]

 In view of the above-mentioned problems in the conventional LED lighting apparatus, the present invention provides a lens cap provided on the incident surface side of a lamp cap to determine the corresponding vertical ray refraction angle and horizontal ray divergence angle of each light source. The first objective is to provide an LED lighting device that can adjust the intensity distribution of the projected light beam in the vertical and horizontal directions to irradiate a specific area, thereby improving the energy use efficiency of the light source. The purpose of

[0010] Furthermore, the LED illuminator having various degrees of freedom in use and an excellent visual image effect by changing the geometrical shape along the vertical and horizontal directions opposite to the light source of each lens unit. The second purpose is to provide

A third object of the present invention is to provide an LED lighting device in which the emission surface of the lamp cap is flat and dust is prevented from accumulating, which is easy to keep clean, and the lighting effect is not reduced from dirt. Aim.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a lens unit provided on a lamp cap, a number of LEDs mounted in a matrix on a substrate so as to emit a light beam, and holding the substrate inside the LED. An LED lighting device comprising: a lamp case having the lamp cap attached to a front opening; wherein the lens unit includes an entrance surface facing the LED, and an exit surface facing forward opposite to the entrance surface. The entrance surface is formed with lens means for refraction of incident light in a matrix, and each lens means has the same or different curvature between adjacent ones along the horizontal direction, and the elevation angle between adjacent ones along the vertical direction. Are arranged on the convex curved surface so as to be gradually different from each other, and when the light beam is focused or dispersed in a specific horizontal range by changing the elevation angle of each of the lens means, the same effect is obtained. At times, the light beam densities in different directions are increased or decreased by selecting the respective curvatures, and the emission surface is configured to present a smooth mirror surface across the front surface.

[0013] A plurality of lens means of the lens unit may be continuously arranged such that the curvature gradually decreases from both sides along the horizontal direction to the center, or the lens unit may be formed as a convex curved surface portion to form the convex portion. On the side of the curved surface facing each of the LEDs, there are provided a number of lens means whose elevation angle changes gradually along the vertical direction and the curvature gradually decreases from both sides to the center in the horizontal direction. Arranged adjacent to each other to form a plurality of neatly arranged light incident areas on the side surface of the convex curved surface portion, or form each of the convex curved surface portions into an equilateral hexagon, or form the lens unit into a lens. The lens plate is assembled by a plate and a light transmitting plate, and the lens plate is provided with lens means for maintaining the same curvature in the horizontal direction by gradually changing the elevation angle along a plurality of vertical directions on the side surface facing the LEDs. Board is it The LED light-transmitting plate may be formed into a flat thin plate, or the light-transmitting plate may be formed into a flat thin plate by continuously arranging a large number of pieces on the side surface facing the LED along the horizontal direction and gradually decreasing the curvature from both sides to the center. The lens unit includes a lens plate and a transmissive linear optical grating, and the lens plate is provided with lens means on the side facing the LED, the elevation angle of which gradually changes along a plurality of vertical directions to maintain the same curvature in the horizontal direction. The transmission type linear optical grating may be provided with a plurality of linear optical grating fringes arranged at equal intervals arranged continuously in a horizontal direction, or the emission surface of the lamp cap may be formed as a smooth surface or a smooth curved surface. It is more preferable that the lens units correspond to at least one LED on a substrate, that the lens units are laid in a tight arrangement, or that they are formed into an equilateral hexagon. No.

In the present invention configured as described above, a plurality of lens units capable of adjusting the vertical and horizontal light intensity distributions corresponding to the light source of the LED are provided on the incident surface of the lamp cap. Therefore, the vertical and horizontal luminance contrast of the light beam projected from the exit surface of the lamp cap can be adjusted as necessary, and the light energy utilization efficiency can be increased. In addition, the lens units with different elevation angles provided along the vertical and horizontal directions on the side of each lens unit facing the LED light source have extremely high design flexibility in terms of optical arrangement. Therefore, the image effect of the human visible range can be more beautiful. In addition, since the emission surface of the lamp cap is formed into a smooth surface or a smooth curved surface, dust can be prevented from accumulating to a large extent, and it is easy to keep clean light rays. The lighting effect does not decrease.

[0015]

[Embodiment of the invention]

 Hereinafter, the present invention will be specifically described based on embodiments, but the present invention is not limited to only this example.

As shown in FIG. 1, in a relatively preferred embodiment of the present invention, a substrate 3 and a lamp cap 4 are sequentially provided in a lamp case 2, a plurality of lens units 5 are formed on the lamp cap 4, and The lamp case 2, the substrate 3 and the lamp cap 4 are penetrated and connected by a large number of assembling means 6.

The lamp case 2 is formed substantially in a trumpet shape and has an enlarged end 20. Along the center of the enlarged end 20, the lamp case 2 has an opening 21 which is openworked. A large number of assembly holes 23 are formed in a wall surface 22 along the periphery of the opening 21.

The substrate 3 is provided with a large number of through holes 30 corresponding to the assembly holes 23, and a large number of LEDs arranged as a light source are mounted on a side surface 31 of the substrate 3 facing the lamp cap 4. . In this embodiment, the LED 32 adopts a divergence angle type of 60 degrees, and the light intensity distribution thereof is such that approximately 80% of the light energy is concentrated within the divergence angle of 45 degrees. The description mainly describes the optical adjustment effect within a divergence angle of 45 degrees.

The lamp cap 4 is provided with a number of assembling parts 40 corresponding to the assembling holes 23 and the through holes 30, and the assembling parts 40, the through holes 30 and the assembling holes 23 are inserted through and connected to the assembling means 6. be able to. The lamp cap 4 is formed into a substantially lower cylindrical body, and a side surface facing the LED 32 is recessed to form an incident surface 41, and an opposite surface facing the front of the incident surface 41 is an emission surface 42. In addition, when the exit surface 42 is used, the exit surface 42 is formed into a smooth surface so as to maintain a clean light beam and further enhance the illumination effect without contaminating and accumulating dirt, and achieve a required illumination effect. Where possible, the exit surface 42 may be formed in any type of smooth plane or smooth curved surface, providing a relatively wide variety of design freedoms.

The plurality of lens units 5 are disposed on the entrance surface 41 of the lamp cap 4, each of which corresponds to at least one LED 32 on the substrate 3, wherein one LED 32 corresponds to one LED 32. Most preferably, it corresponds to the lens unit 5. Further, each lens unit 5 is provided with lens means 50 on the side surface facing the LED 32 so as to maintain the same or unequal curvature in the horizontal direction with different elevation angles along the vertical direction. As shown in FIGS. 1 and 3 (that is, a relatively preferred first embodiment), the lens unit 5 is designed to be a single member so as to have a double adjustment effect by a single member. Alternatively, as shown in FIGS. 6 and 7 (second and third embodiments, respectively), the lens unit 50 is combined with the lens unit 50 and the lens plate 53 using a separation method. It may be handled by two separate members. Further, the elevation angle in the vertical direction, the curvature in the horizontal direction, and the mutual curvature relationship of each lens means 50 may be appropriately adjusted and changed according to the functional requirements of the product, that is, in order to achieve a specific lighting effect, As shown in FIG. 1, the optical design of the lens unit 5 is not limited to gradually changing the elevation angle of each lens means 50 along the vertical direction (increase gradually when viewed in the opposite direction), and also changing the curvature along the horizontal direction on both sides. Rather than being limited to only gradually decreasing from the sides to the center, the designer can enjoy a very wide range of design freedom by operating and appropriately combining the optical characteristics of a large number of lens means 50. can do. On the other hand, in order to make full use of the space on the incident surface 41, the shape of the lens unit 5 is advanced and provided in an equilateral hexagon, and when the lens units 5 are laid closely together, the excess of the incident surface 41 is obtained. The gap can be controlled to a minimum to maximize space utilization.

At the time of assembling, as shown in FIG. 1, first, the through holes 30 of the substrate 3 on which a number of LEDs 32 have already been arranged correspond to the assembling holes 23 of the lamp case 2, and the side surfaces 31 of the substrate 3 The opening 21 is sealed by attaching the opposite side corresponding to the back to back to the wall surface 22, and then through the through hole 30 and the assembling hole 23 of the assembling portion 40 of the lamp cap 4 on which a plurality of lens units 5 have already been laid. Correspondingly, the entrance surface 41 of the lamp cap 4 is covered correspondingly to the substrate 3 and covers the enlarged end portion 20 of the lamp case 2, and finally, a lamp case is formed by a large number of assembling means 6 (here, bolts are used). 2. The board 3 and the lamp cap 4 are integrally inserted and screwed together, and the assembly of the present invention is completed as shown in FIG.

FIG. 3 shows a relatively preferred first embodiment in which a large number of lens means 50 of each lens unit 5 according to the present invention are integrally formed on a convex curved surface portion 52. The convex curved surface portion 52 has a vertical direction. The lens means 50 is provided with lens units 50 having different angles of curvature in which the elevation angle gradually changes in multiple steps along each step and each step is continuously arranged along the horizontal direction. The lens means 50 are arranged adjacent to each other, and the convex curved surface portion 52 is provided. The whole is formed by a light incident area 520 having a number of vertical inclined surfaces and horizontal curved surfaces.

Referring to FIG. 3 to FIG. 5, as can be seen from the above description, this embodiment mainly adjusts the light distribution effect of the LED 32 that concentrates 80% of the light energy within the 45-degree emission angle. The upper half luminous flux and the lower half luminous flux diverge upward and downward along the vertical direction of the LED 32 light source (the part within the 45-degree launch angle), respectively, and the effective illumination range in which drivers and passers-by can be seen. Otherwise, the upper half of the light source of the LED 32 must be adjusted for downward refraction, and the lower half of the light source must be adjusted for upward refraction, so that the lens means 50 moves upward along the vertical direction. When five steps are provided from the bottom to the bottom, the lens means, e.g., 50 ₁₁ , 50 ₂₁ , 50 ₃₁ , 50 ₄₁ , 50 ₅₁ , the elevation angle (indicated by ψ) must be from top to bottom as shown in FIG. It must be changed so that it gradually decreases to 1>ψ2>ψ3>ψ4> ψ5. Also, when increasing more beautify visible range imaging effect of human as well as the divergence angle in the horizontal direction (i.e., viewing angle expanding), to the lens unit 50 along the horizontal direction from left to right nine stairs 50 _11, 50 _12, 50 ₁₃ , 50 ₁₄ , 50 ₁₅ , 50 ₁₆ , 50 ₁₇ , 50 ₁₈ , 50 ₁₉ , the curvature (curvature, c) of each lens means 50 ₁₁ to 50 ₁₉ must be centered from both sides As shown in Fig. 5, it must be gradually reduced to c1>c2>c3>c4> c5, and c9>c8>c7>c6> c5. Therefore, utilizing the characteristic that the lens means 50 has a specific elevation angle and curvature at each light incidence area 520, the light flux of the LED 32 light source is guided to the specific area to newly add vertical and horizontal directions. The brightness contrast can be adjusted to make full use of the light energy to produce the best lighting effect.

FIG. 6 shows a second preferred embodiment of the present invention, which differs from the first embodiment in that the lens means 50 of the lens unit 5 is integrally formed as a single member. Instead, it is assembled by the lens plate 53 and the light transmitting plate 54 in a design scheme separated into both members. The lens plate 53 has a lens means 50 (e.g., five steps of lens means 500 to 504 having five steps) whose elevation angle gradually changes along the vertical direction and keeps the same curvature in the horizontal direction on the side opposite to the LED 32. The light-transmitting plate 54 is formed into a flat thin plate as a whole, and is continuously arranged along the horizontal direction on the side facing the LED 32, and the curvature gradually increases from both sides to the center. A decreasing convex curved surface portion 52 (here, each of which is constituted by a multi-step convex curved surface portion 540 having an appropriate curvature) is provided. Further, since the lens plate 53 and the light transmitting plate 54 are two independent members each having a specific function, the same optical modulation effect can be obtained even if the spatial arrangement method of the lens plate 53 and the light transmitting plate 54 is changed at the time of application. Can occur. In other words, the light beam of the light source of the LED 32 may first pass through the lens plate 53 and then pass through the light transmitting plate 54 as shown in FIG. The light distribution effect may be modulated by the lens plate 53 after the luminous flux of the light source of the LED 32 is first passed through the light transmission plate 54 by adjusting the relative position between the light transmitting plate 54 and the light transmitting plate 54. The degree of freedom of the optical design is further improved.

FIG. 7 shows a third preferred embodiment of the present invention, in which the lens unit 5 employs a separate design method for both members as in the second embodiment. The lens unit 5 here includes a lens plate 53 and a transmission type linear optical grating 55. Among them, the lens plate 53 has a plurality of lens means 50 (similarly to five steps of lens means 500 to 500) on the side opposite to the LED 32 to maintain the same curvature in the horizontal direction by gradually changing the elevation angle along the same vertical direction. 504), and the transmission linear optical grating 55 is provided with a plurality of linear optical grating fringes 550 continuously arranged at equal intervals along the horizontal direction, and each optical grating fringe 550 adjacent to each other is provided. The space is formed in the convex curved surface portion 551, and the same light distribution effect as the convex curved surface portion 52 of the lens unit 5 of the second embodiment can be provided. The transmission type linear optical grating 55 actually achieves an optical refraction phenomenon similar to the convex curved surface portion 52 or the light transmitting plate 54 by using the principle of optical diffraction. Rather than achieving a light distribution effect, a transmissive linear optical grating 55 with special checkerboard spacing is used to meet specific functional requirements.

It should be noted that the LED having a divergence angle of 60 degrees employed in the present embodiment mainly modulates the 80% light energy within the divergence angle of 45 degrees. The 20% light energy outside the emission angle is freely diverged and transmitted through the lens unit 5 without being modulated, so that the strongest luminous flux within the 45-degree divergence angle of the LED light source (up to 80% light energy) is obtained. The best light energy utilization can be achieved by the sufficient adjustment light distribution effect of the lens unit 5, and the surplus 20% light energy covers the entire lens unit 5 and is reduced by the local light spot. Impact can be reduced.

[0027]

[Effect of the invention]

 As described above, in the present invention, a plurality of lens units capable of adjusting the light intensity distribution in the vertical and horizontal directions corresponding to the light source of the LED are provided on the incident surface of the lamp cap. Usage efficiency can be increased. In addition, the lens means having different elevation angles, which are designed along the vertical and horizontal directions on the side of each lens unit facing the LED light source, respectively, have extremely excellent design flexibility in terms of optical arrangement, and require human beings. Can be more beautifully imaged. In addition, the structure in which the emission surface of the lamp cap is formed into a smooth surface can prevent dust from being accumulated, and can easily maintain clean light, so that the lighting effect does not deteriorate from dirt. Therefore, the disadvantages of the conventional LED lighting device can be surely improved by the present invention.

[Brief description of the drawings]

FIG. 1 is an exploded view of a first preferred embodiment of the present invention.

FIG. 2 is a three-dimensional view of an assembled state of FIG. 1;

FIG. 3 is an enlarged three-dimensional view showing an outline of a main part lens means in FIG. 1;

4 is a three-dimensional view showing an outline of refraction of a light beam in a vertical direction by a lens unit in FIG. 3;

5 is a three-dimensional view showing an outline of refraction of a light beam in a horizontal direction by a lens unit in FIG. 3;

FIG. 6 is a three-dimensional exploded view of a main part of a second preferred embodiment of the present invention (another embodiment in which lens means is changed).

FIG. 7 is an exploded perspective view of a main part of a third preferred embodiment of the present invention.

FIG. 8 is a plan view showing an outline of light beam refraction when US Pat. No. 5,174,649 is used.

FIG. 9 is a side view showing an outline of light beam refraction when US Pat. No. 5,174,649 is used.

FIG. 10 is a side view showing an outline of light beam refraction when US Pat. No. 5,343,330 is used.

FIG. 11 is a perspective view of a main part of a prism of US Pat. No. 5,833,355.

FIG. 12 is a side view showing an outline of light beam refraction when US Pat. No. 5,833,355 is used.

[Explanation of symbols]

 2 Lamp case 20 Enlarged end 21 Opening 22 Wall 23 Assembly hole 3 Substrate 30 Through hole 31 Side 32 LED 4 Lamp cap 40 Assembly part 41 Incident surface 42 Exit surface 5 Lens unit 50 Lens means 500-504 Lens means ψ1-ψ2 Elevation angle c1 to c2 Curvature 52 Convex curved surface 520 Light incident area 53 Lens plate 54 Light transmitting plate 540 Convex curved surface 55 Transmission linear optical grating 550 Optical lattice fringe 551 Convex curved surface 6 Assembly means

Claims (12)

[Utility model registration claims] 1. A lens unit provided in a lamp cap, a large number of LEDs mounted in a matrix on a substrate so as to emit a light beam, the substrate being held therein, and the lamp cap being provided in a front opening. An LED lighting device comprising a lamp case equipped with a lens unit, wherein the lens unit has an entrance surface facing the LED, and an exit surface facing forward on the opposite side of the entrance surface, and the entrance surface has a large number of matrices. The lens means for refracting incident light is formed, and each lens means has a convex curved surface such that adjacent curvatures along the horizontal direction are the same or different from each other, and elevation angles between the vertical neighbors are gradually different from each other. The lens means are focused on or dispersed in a specific horizontal range by changing the elevation angle of each of the lens means. Ri different directions of increase or decrease the light beam density, further LED lighting device in which the exit surface is the shape of a smooth mirror surface over the front. 2. The LED lighting device according to claim 1, wherein the plurality of lens means of the lens unit are arranged continuously so that the curvature gradually decreases from both sides along the horizontal direction to the center. 3. The lens unit has a convex curved surface portion.
On the side surface of the convex curved surface portion opposed to the LEDs, a plurality of lens means are provided, the elevation angle of which gradually changes along the vertical direction and the curvature gradually decreases from both sides to the center in the horizontal direction. 3. The LED lighting device according to claim 2, wherein the LED lighting devices are arranged adjacent to each other so as to form a plurality of orderly arranged light incident areas on the side surface of the convex curved surface portion. 4. The LED lighting device according to claim 3, wherein each of the convex curved portions is formed into an equilateral hexagon. 5. The lens unit is assembled by a lens plate and a light transmitting plate, and the lens plate has a plurality of vertical elevational angles on a side opposite to the LEDs to maintain the same curvature in the horizontal direction. A lens means is provided, and the light transmitting plate is provided with a plurality of convexly curved surface portions on the side surface facing the LEDs, which are continuously arranged along a horizontal direction and whose curvature gradually decreases from both sides to the center. Item 3. An LED lighting device according to Item 2. 6. The LED lighting device according to claim 5, wherein the light transmitting plate is formed into a flat thin plate shape. 7. The lens unit includes a lens plate and a transmission type linear optical grating, and the lens plate has a plurality of vertical elevational angles gradually changed on a side opposite to the LED to have the same curvature in a horizontal direction. 2. The LED lighting device according to claim 1, further comprising a lens means for keeping, wherein said transmission type linear optical grating is provided with a plurality of linear optical grating stripes arranged at equal intervals and continuously arranged in a horizontal direction. 8. The LED lighting device according to claim 1, wherein the emission surface of the lamp cap is formed as a smooth surface. 9. The lamp cap according to claim 1, wherein the emission surface of the lamp cap is formed into a smooth curved surface.
LED lighting device. 10. The LED lighting device according to claim 1, wherein each of the lens units corresponds to at least one LED on a substrate. 11. The LED lighting device according to claim 1, wherein the lens units are laid in a tight arrangement. 12. The LED lighting device according to claim 1, wherein the lens unit is formed into an equilateral hexagon.