Abstract:
Provided is a light emitting device which can uniformly diffuse and radiate light from all the regions of the globe of an LED bulb without deteriorating light transmission efficiency. A light emitting device is provided with a light scattering/guiding globe and an LED which is disposed on one end of the light scattering/guiding globe. The light scattering/guiding globe is a body with no air released from the inside and is composed of a light scattering/guiding material having light scattering particles contained therein. The globe has the bottom surface on the side of the LED, and is provided with a first light incoming surface as a first hollow section, which is formed in a circular cone shape in the light outputting direction from the bottom surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a national phase of an International application No. PCT/JP2010/001918 filed on Mar. 17, 2010, which relates to and claims priority from Japanese patent application No. 2009-097103 filed on April 13. The contents of the International application and the Japanese application are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a light emitting device and a bulb-type LED lamp. 
         [0004]    2. Description of Related Art 
         [0005]    A traditional filament bulb has a diffusion film formed on a glass bulb (a globe) for controlling the glare in order to prevent a high intensity of a point light source from causing a discomfort feeling on humans. In the meantime, a bulb-type fluorescent light has a light emitting property that an entire lamp emits fluorescent light, and therefore glaring can easily be controlled. 
         [0006]    On the other hand, taking advantage of high-power output and high-efficiency technologies of light emitting diodes (LEDs), light bulbs that uses an LED as a light source are put into practical use in recent years. Meanwhile, an LED has a small-sized light source, and its brightness is extremely high, and furthermore it has a light emitting property that it radially emits light in certain directions. Therefore, when being used as a light source of a light bulb, it is difficult for an LED to diffuse light uniformly all over a globe. 
         [0007]    To solve the difficulty described above, proposed in Patent Document 1 is an LED light bulb equipped with a diffusion sheet placed on an external surface of a translucent globe, the LED light bulb being able to nearly homogenize its brightness.
   Patent Document 1: JP 2008-91140 A   
 
       SUMMARY OF THE INVENTION 
       [0009]    Since the LED light bulb proposed in Patent Document 1 is equipped with a diffusion sheet placed on an external surface of a translucent globe, the diffusion sheet lowers a light transmission rate, and accordingly the LED light bulb has a disadvantage that an efficiency of light radiation becomes deteriorated. Furthermore, there exists another disadvantage that additional work of placing the diffusion sheet is required, and there is also an unfavorable possibility that the diffusion sheet is peeled sometimes. 
         [0010]    Moreover, in the LED light bulb proposed in Patent Document 1, a plurality of LEDs are used. A reason for using the plurality of LEDs is that using a single LED makes it further impossible to diffuse light uniformly all over the globe. In the meantime, using the plurality of LEDs makes it difficult to achieve a reduction in power consumption. 
         [0011]    The present invention has been achieved under the circumstance described above, and it is an object of the present invention to provide a light emitting device and a bulb-type LED lamp that enable uniform light diffusion and radiation over an entire area of a globe of an LED light bulb as well as reduction of the number of LEDs to be used, without lowering a light transmission rate. 
         [0012]    A first aspect of the present invention relates to a light emitting device. Namely, a light emitting device according to the present invention comprises: a globe; and an LED which is disposed on one end of the globe; in which: the globe is a solid component made of a light scattering/guiding member containing light scattering particles, and the globe has a bottom plane facing the LED, and provided with a first hollow section, which is formed in a conical shape in the light outputting direction from the bottom plane. 
         [0013]    The light emitting device may further comprise a second hollow section shaped around the first hollow section portion, in which the second hollow section has a concave shape in which a position located further away from the LED toward an outer circumference side has a deeper depth. 
         [0014]    Alternatively, the light emitting device may further comprise a second hollow section between the bottom plane of the conical shape of the first hollow section and the LED, in which the second hollow section has a circular shape larger than the bottom plane, and has a concave shape in which a position located further away from the LED toward an outer circumference of the circular shape has a shallower depth. 
         [0015]    The globe may be at least partially shaped like a ball. Alternatively, the globe may be at least partially shaped like a circular cylinder, and one end of the circular cylinder opposite from the LED, may be shaped like a convex lens. 
         [0016]    The light emitting device may comprise a plurality of LEDs, the emission colors of which are different from each other, disposed on the one end of the globe; and a dimming controller for controlling light emission intensity individually of the plurality of LEDs. 
         [0017]    A second aspect of the present invention relates to a bulb-type LED lamp. Namely, a bulb-type LED lamp according to the present invention comprises the light emitting device according to the present invention. 
         [0018]    According to the present invention, it becomes possible to diffuse and radiate light uniformly over an entire area of a globe of an LED light bulb, and to reduce the number of LEDs to be used, without lowering a light transmission rate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a general configuration drawing of a bulb-type LED lamp according to a first embodiment of the present invention. 
           [0020]      FIG. 2  shows traveling paths of rays of light emitted from an LED placed in a light scattering/guiding globe shown in  FIG. 1 , wherein  FIG. 2  shows relationships between the traveling paths of the rays of light and a first light incoming surface. 
           [0021]      FIG. 3  shows traveling paths of rays of light emitted from the LED placed in the light scattering/guiding globe shown in  FIG. 1 , wherein  FIG. 3  shows relationships between the traveling paths of the rays of light and a second light incoming surface. 
           [0022]      FIG. 4  shows a light intensity distribution of output light from a radiation surface of the bulb-type LED lamp shown in  FIG. 1 . 
           [0023]      FIG. 5  shows a brightness of light emission from a side surface of the light scattering/guiding globe shown in  FIG. 1 . 
           [0024]      FIG. 6  shows a brightness of light emission from a top surface of the light scattering/guiding globe shown in  FIG. 1 . 
           [0025]      FIG. 7  is a general configuration drawing of a bulb-type LED lamp according to a second embodiment of the present invention. 
           [0026]      FIG. 8  shows traveling paths of rays of light emitted from an LED placed in a light scattering/guiding globe shown in  FIG. 7 . 
           [0027]      FIG. 9  shows a light intensity distribution of output light from a radiation surface of the bulb-type LED lamp shown in  FIG. 7 . 
           [0028]      FIG. 10  shows a radiated light distribution at a position 1 meter ahead of the bulb-type LED lamp shown in  FIG. 7 . 
           [0029]      FIG. 11  shows a state of the radiated light distribution, shown in  FIG. 10 , in an area around a 0-mm position while a horizontal axis and a vertical axis representing a distance and a luminous intensity, respectively. 
           [0030]      FIG. 12  is a general configuration drawing of a bulb-type LED lamp according to a third embodiment of the present invention. 
           [0031]      FIG. 13  shows traveling paths of rays of light emitted from an LED placed in a light scattering/guiding globe shown in  FIG. 12 , wherein  FIG. 13  shows relationships between the traveling paths of the rays of light and a first light incoming surface. 
           [0032]      FIG. 14  shows traveling paths of rays of light emitted from the LED placed in the light scattering/guiding globe shown in  FIG. 12 , wherein  FIG. 14  shows relationships between the traveling paths of the rays of light and a second light incoming surface. 
           [0033]      FIG. 15  shows a light intensity distribution of output light from a radiation surface of the bulb-type LED lamp shown in  FIG. 12 . 
           [0034]      FIG. 16  shows a brightness of light emission from a side surface of the light scattering/guiding globe shown in  FIG. 12 . 
           [0035]      FIG. 17  shows a brightness of light emission from a top surface of the light scattering/guiding globe shown in  FIG. 12 . 
           [0036]      FIG. 18  is a general configuration drawing of a bulb-type LED lamp according to a fourth embodiment of the present invention. 
           [0037]      FIG. 19  shows traveling paths of rays of light emitted from an LED placed in a light scattering/guiding globe shown in  FIG. 18 . 
           [0038]      FIG. 20  shows a light intensity distribution of output light from a radiation surface of the bulb-type LED lamp shown in  FIG. 18 . 
           [0039]      FIG. 21  shows a radiated light distribution at a position 1 meter ahead of the bulb-type LED lamp shown in  FIG. 18 . 
           [0040]      FIG. 22  shows a state of the radiated light distribution, shown in  FIG. 21 , in an area around a 0-mm position while a horizontal axis and a vertical axis representing a distance and a luminous intensity, respectively. 
           [0041]      FIG. 23  shows a layout state of 3 LEDs and a dimming controller according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    (Regarding a Bulb-Type LED Lamp  1  According to a First Embodiment of the Present Invention) 
         [0043]    Explained below is a structure of a bulb-type LED lamp  1  according to a first embodiment of the present invention. A light emitting device is explained together with the explanation on the bulb-type LED lamp  1 . The bulb-type LED lamp  1  principally comprises a light scattering/guiding globe  10  that contains light scattering particles, an LED  11 , a circuit board  12 , a heat dissipating plate  13 , a power supply section  14 , a heat dissipating cover  15 , and a lamp base  16 . 
         [0044]    The light scattering/guiding globe  10  is shaped like a bulb globe with a light scattering/guiding material. Being different from a conventional bulb globe, the light scattering/guiding globe  10  is a solid component whose internal part is made solid. The light scattering/guiding globe  10  is a resin molded body, for example, made of transparent poly-methyl methacrylate (hereinafter abbreviated to “PMMA”). In the PMMA to be used for shaping the light scattering/guiding globe  10 , dispersed are translucent silicone particles with their particle diameter of 1 to 10 micron meters, as light scattering particles. Thus, the light scattering/guiding globe  10  works as a light dispersing component. 
         [0045]    The LED  11  is, for example, a white LED. The circuit board  12  comprises a circuit pattern for illuminating the LED  11 , and it is also equipped with required elements (such as a resistor, a constant voltage diode, and so on which are not shown). The heat dissipating plate  13  is made of, for example, a metal plate for absorbing the heat of the LED  11 . The power supply section  14  is equipped with a power supply circuit for supplying the LED  11  with a constant current. In other words, the power supply section  14  converts an AC current (100V) into a DC current to generate a voltage value and a constant current value that meet rated specification values for the LED  11 . 
         [0046]    In the meantime, the heat dissipating cover  15  is connected to the heat dissipating plate  13  in order to externally dissipate the heat absorbed by the heat dissipating plate  13 . The lamp base  16  is prepared according to the same standards as for a lamp base of a traditional filament bulb so that the bulb-type LED lamp  1  can be installed to a device to which a traditional filament bulb has been installed up to that time. 
         [0047]    A section positioned higher than the circuit board  12  in  FIG. 1  corresponds to a light emitting device that is claimed. Alternatively, one or more of the circuit board  12 , the heat dissipating plate  13 , the power supply section  14 , and the heat dissipating cover  15  may be comprised in the light emitting device. 
         [0048]    The light scattering/guiding globe  10  is further explained in detail. As described above, the light scattering/guiding globe  10  is shaped with a light scattering/guiding material. The light scattering/guiding globe  10  comprises a first light incoming surface  20  and a second light incoming surface  21 , through both of which light from the LED  11  enters the light scattering/guiding globe  10 . The light scattering/guiding globe  10  further comprises a first hollow section  22  so surrounded by the first light incoming surface  20  as to be conical, a second hollow section  24  so surrounded by the second light incoming surface  21 , a columnar surface  23 , and the circuit board  12  as to be shaped surrounding the first hollow section  22 . The light scattering/guiding globe  10  still further comprises a radiation surface  30  for externally outputting light from an internal section of the light scattering/guiding globe  10 . 
         [0049]      FIG. 2  and  FIG. 3  show traveling paths of rays of light emitted from the LED  11  placed in the light scattering/guiding globe  10 . As shown in  FIG. 2 , relationships between the LED  11  and the first light incoming surface  20  are set in such a way that, among rays of light emitted from the LED  11 , those emitted at a small angle (0 to 45 degrees) in relation to an optical-axis normal line “K” enter the light scattering/guiding globe  10  through the first light incoming surface  20 . 
         [0050]    The first light incoming surface  20  is shaped by deeply hollowing out a central inside surface of the light scattering/guiding globe  10 , which is almost spherical, so as to make the surface part conical. The rays of light emitted at a small angle (0 to 45 degrees) in relation to the optical-axis normal line “K” are refracted by the first light incoming surface  20  so that the rays of light enter the light scattering/guiding globe  10  at an entrance angle in relation to the optical-axis normal line “K”, which is greater than the emission angle. 
         [0051]    When colliding with a scattering fine particle as a light scattering particle, each ray of light that has entered the light scattering/guiding globe  10  is scattered in all directions while having a large directivity angle toward a front side in a traveling direction. Repeating such a scatter operation multiple times (which is called “multiple-scattering”), the ray of light travels forward in the light scattering/guiding globe  10 . At the time of such a scatter operation, no light absorption happens. Meanwhile, there are remarkably few rays of light that return backward due to the scatter operation, and therefore most rays of light can be output from the radiation surface  30 . 
         [0052]    The first light incoming surface  20  plays a role of significantly changing directions of incoming rays of light from the LED  11 . Then, adjusting incident angles of rays of light makes it possible to output the rays of light evenly from an entire section of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0053]    Explained next with reference to  FIG. 2  are rays of light that enter from the first light incoming surface  20 , pass through the light scattering/guiding member, and are output from the radiation surface  30  as outgoing rays of light L 1  to L 10 . Incidentally, an upper side/a lower side/a right side/a left side in the following explanation correspond to an upper side/a lower side/a right side/a left side in the drawing, respectively. 
         [0054]    The outgoing ray of light L 1  is radiated almost in a direction of the optical-axis normal line “K” of the LED  11  so as to enter the light scattering/guiding globe  10  almost along a center line of the first hollow section  22  of the first light incoming surface  20 . Therefore, almost without being refracted at the first light incoming surface  20 , the outgoing ray of light L 1  enters the light scattering/guiding globe  10 . Then, being multiple-scattered and refracted somewhat in the light scattering/guiding globe  10 , the outgoing ray of light L 1  is output in an upper right direction from a position in the vicinity of a top of the light scattering/guiding globe  10 . 
         [0055]    The outgoing ray of light L 2  is radiated in a direction tilted to the right side for about 20 degrees from the optical-axis normal line “K” of the LED  11  so as to enter the light scattering/guiding globe  10  while being refracted to the right side by the first light incoming surface  20 . Then, being multiple-scattered in the light scattering/guiding globe  10 , the incoming ray of light collides with the radiation surface  30 . At the time, the incident angle with respect to the radiation surface  30  is greater than a critical angle that brings about a total reflection, and therefore the ray of light is totally reflected. Then, the outgoing ray of light L 2 , which has been totally reflected in an upper left direction by the radiation surface  30  of the light scattering/guiding globe  10 , collides with a right-hand position of the radiation surface  30 , which is in the vicinity of the top of the light scattering/guiding globe  10 . At the time, the incident angle is smaller than the critical angle, and therefore the ray of light is output in an upper left direction from the radiation surface  30 . 
         [0056]    The outgoing ray of light L 3  is radiated in a direction tilted to the right side for about 15 degrees from the optical-axis normal line “K” of the LED  11  so as to enter the light scattering/guiding globe  10  while being refracted somewhat to the right side by the first light incoming surface  20 , and then the ray of light is multiple-scattered therethrough. Subsequently, almost without any further refraction, the ray of light is output in an upper right direction from a right position of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0057]    The outgoing ray of light L 4  reaches a left position of the first light incoming surface  20  at an incident angle greater than that of the outgoing ray of light L 3  so that the ray of light is totally reflected by the first light incoming surface  20 . Then, at a position of the first light incoming surface  20 , which is opposite to the left position mentioned above, the ray of light enters the light scattering/guiding globe  10  while being refracted somewhat to the right side, and it is multiple-scattered therethrough. While being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 4  is refracted to the right side, and output in an upper right direction from a right position of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0058]    The outgoing ray of light L 5  is radiated toward the left side from the LED  11 , and the ray of light enters the light scattering/guiding globe  10  while being refracted somewhat to the left side by the first light incoming surface  20 . Subsequently, being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 5  reaches the radiation surface  30 . The outgoing ray of light L 5  is totally reflected in an upper right direction by the radiation surface  30 . Then, while being multiple-scattered in the light scattering/guiding globe  10 , the ray of light is refracted toward the right side, and it is output horizontally in a right direction from a right position of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0059]    The outgoing ray of light L 6  is radiated from the LED  11  in a direction tilted to the right side for about 30 degrees from the optical-axis normal line “K”; and as being refracted somewhat to the right side by the first light incoming surface  20 , the ray of light enters the light scattering/guiding globe  10 . Then, while being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 6  is further refracted to the right side, and output in a somewhat upper right direction from a bottom position at the right side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0060]    The outgoing ray of light L 7  is radiated from the LED  11  in a direction tilted to the left side for about 8 degrees from the optical-axis normal line “K”, and it enters the light scattering/guiding globe  10 , as being remarkably refracted to the left side by the first light incoming surface  20 . The LED  11  is not a point source of light, and therefore being different from the outgoing ray of light L 4  that is totally reflected, the outgoing ray of light L 7  is not totally refracted. Namely, there exist some rays of light that enters the light scattering/guiding globe  10  without total reflection. Then, while being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 7  is refracted somewhat to the left side, and output in an upper left direction from an upper position at the left side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0061]    The outgoing ray of light L 8  is radiated from the LED  11  in a direction tilted to the right side for about 35 degrees from the optical-axis normal line “K”, and it enters the light scattering/guiding globe  10 , as being totally reflected to the left side by the first light incoming surface  20 . Then, while being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 8  is refracted somewhat to the lower side, and output in an upper left direction from a left position of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0062]    The outgoing ray of light L 9  is radiated from the LED  11  in a direction tilted to the right side for about 8 degrees from the optical-axis normal line “K”, and then totally reflected to the left by the first light incoming surface  20 . Then, at a position of the first light incoming surface  20 , which is opposite to the totally-reflecting position mentioned above, the outgoing ray of light L 9  enters the light scattering/guiding globe  10  while being refracted to the left. Subsequently, while being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 9  is output in an upper left direction from an upper position at the left side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0063]    The outgoing ray of light L 10  is radiated from the LED  11  in a direction tilted to the left side for about 35 degrees from the optical-axis normal line “K”, and it enters the light scattering/guiding globe  10 , as being refracted somewhat to the left side by the first light incoming surface  20 . Then, while being multiple-scattered in the light scattering/guiding globe  10 , the outgoing ray of light L 10  is output in an upper left direction from a lower position at the left side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0064]      FIG. 3  shows outgoing rays of light L 11  to L 20  that enter the first light incoming surface  20  and move toward the second light incoming surface  21  through their traveling paths. The LED  11  and the second light incoming surface  21  are set in such a way that, among rays of light emitted from the LED  11 , those emitted at a large angle (45 to 90 degrees) in relation to an optical-axis normal line “K” enter the light scattering/guiding globe  10  through the first light incoming surface  20 , and subsequently they are totally reflected by the second light incoming surface  21  so as to return into the light scattering/guiding globe  10 . The second light incoming surface  21  is placed as a top surface of the second hollow section  24  shaped around the first hollow section  22  that is surrounded by the first light incoming surface  20 , and the second light incoming surface  21  is shaped with a circular form that is greater than a bottom plane of the first hollow section  22  being shaped conically. Then, the second hollow section  24  has a concave shape in which a position located further away from the LED  11  toward an outer circumference of the circular form has a deeper depth. In other words, the second light incoming surface  21  is shaped like a concave form of a concave lens so as to have a function like a kind of concave mirror. 
         [0065]    A ray of light tilted at a large angle (45 to 90 degrees) in relation to an optical-axis normal line “K” enters the light scattering/guiding globe  10  through the first light incoming surface  20 , and subsequently it is reflected by the second light incoming surface  21  so as to move upward in the light scattering/guiding globe  10  at a smaller traveling tilt angle in relation to an optical-axis normal line “K.” As a result, an excessive output of light from around a root section of the radiation surface  30  of the light scattering/guiding globe  10  can be controlled so that rays of light are evenly radiated from all over the light scattering/guiding globe  10 . 
         [0066]    Next, the outgoing rays of light L 11  to L 20  are explained with reference to  FIG. 3 . Incidentally, an upper side/a lower side/a right side/a left side in the following explanation correspond to an upper side/a lower side/a right side/a left side in the drawing, respectively. 
         [0067]    The outgoing ray of light L 11  is radiated in a direction tilted to the left side for about 85 degrees (almost horizontally toward the left side) from the optical-axis normal line “K” of the LED  11  to pass through the first light incoming surface  20  and enter the light scattering/guiding globe  10 . Subsequently, the outgoing ray of light L 11  is totally reflected upward by a left side slope of the second light incoming surface  21  to move in such a way as to lift off through a spherical section of the light scattering/guiding globe  10 . Then, while being multiple-scattered in the light scattering/guiding globe  10 , the ray of light L 11  is refracted to the right side, and output in an upper right direction from a right position in the vicinity of the top of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0068]    The outgoing rays of light L 12 , L 13 , and L 14  are radiated in directions tilted to the right side for about 90 degrees (almost horizontally toward the right side) from the optical-axis normal line “K” of the LED  11  to enter the light scattering/guiding globe  10  almost without any refraction at the first light incoming surface  20 . Subsequently, each of the rays of light L 12 , L 13 , and L 14  travels while being multiple-scattered, and each of them is totally reflected upward by a right side slope of the second light incoming surface  21  to move in such a way as to lift off through the spherical section of the light scattering/guiding globe  10 . Then, while being multiple-scattered in the spherical section of the light scattering/guiding globe  10 , each of them is refracted to the right side, and output in an upper right direction from an upper position of the right side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0069]    The outgoing rays of light L 15 , L 16 , and L 18  are radiated in directions tilted to the left side for about 60 degrees from the optical-axis normal line “K” of the LED  11  to enter the light scattering/guiding globe  10 , as being refracted somewhat to the left side by the first light incoming surface  20 . Subsequently, each of the rays of light L 15 , L 16 , and L 18  travels through the light scattering/guiding globe  10  while being multiple-scattered, and it is totally reflected upward by the second light incoming surface  21  to move in such a way as to lift off. Then, from an upper position of the left side of the radiation surface  30  in the spherical section of the light scattering/guiding globe  10 , the outgoing rays of light L 15  and L 16  are output in upper right directions, and meanwhile the outgoing ray of light L 18  is output in an upward direction. 
         [0070]    The outgoing ray of light L 17  is radiated in a direction tilted to the right side for about 60 degrees from the optical-axis normal line “K” of the LED  11  to enter the light scattering/guiding globe  10 , as being refracted somewhat to the right side by the first light incoming surface  20 . Then, the outgoing ray of light L 17  travels, while being multiple-scattered in the light scattering/guiding globe  10 , and it is totally reflected upward by the second light incoming surface  21  so as to be output in an upper left direction from an upper position of the left side of the radiation surface  30  of the light scattering/guiding globe  10 . 
         [0071]    Detailed explanations with regard to the outgoing rays of light L 19  and L 20  are omitted. Both the outgoing rays of light L 19  and L 20  are emitted from the LED  11  in directions largely tilted (within a range from 45 to 90 degrees) from the optical-axis normal line “K.” Having passed through the first light incoming surface  20 , both the rays of light are totally reflected by the second light incoming surface  21  so as to move in such a way as to lift off toward the spherical section of the light scattering/guiding globe  10 . Being multiple-scattered in the light scattering/guiding globe  10  so as to change their traveling directions, both the rays of light are output from upper positions of the radiation surface  30  in the end. 
         [0072]    Besides that, being just a little in comparison with the outgoing rays of light L 1  to L 20 , observed are some rays of light that repeat total reflection and multiple-scattering within the light scattering/guiding globe  10  and eventually disappear in the end, without being output from the light scattering/guiding globe  10 . 
         [0073]      FIG. 4  shows a light intensity distribution of output light from the radiation surface  30  of the bulb-type LED lamp  1 . The LED  11  is placed at an intersection point “M” of a line connecting a 90-degree orientation with a 270-degree orientation and the optical-axis normal line “K.” An actual light intensity distribution is represented as a sphere made up by turning a distribution line “N” shown in  FIG. 4  around the optical-axis normal line “K.” As shown in  FIG. 4 , a highest light intensity is observed at a direction of the optical-axis normal line “K” of the LED  11 . Furthermore, it is understood that an angular range of 90 degrees in total with its centerline at the direction of the optical-axis normal line “K” has almost the same output of light flux as the direction of the optical-axis normal line “K” has. On this occasion, a scale for a distance from the light source is provided with values of 0.1 to 1, and these values represent relative locations in view from the light source without any particular unit. The same way of explanation is also applied to  FIG. 9 ,  FIG. 14 , and  FIG. 19 , which are described later. Moreover, as shown in  FIG. 4 , a certain amount of light is output in a rearward direction of the LED  11 , and the light intensity distribution is similar to that of a filament bulb. Such a movement of light toward a rear side of the LED  11  has been achieved in the past with an extra member, such as a reflection plate, in a conventional LED lighting system. 
         [0074]      FIG. 5  shows a brightness of light emission from a side surface of the light scattering/guiding globe  10 . In the meantime,  FIG. 6  shows a brightness of light emission from a top surface of the light scattering/guiding globe  10 . For both  FIG. 5  and  FIG. 6 , a brightness of the light scattering/guiding globe  10  is measured at a position 1 meter away from the light scattering/guiding globe  10 . A right drawing of  FIG. 5  represents the brightness distribution of a left drawing of  FIG. 5  with numerical values. The right drawing of  FIG. 5  shows the brightness distribution in candela (cd). In the meantime, a right drawing of  FIG. 6  represents the brightness distribution of a left drawing of  FIG. 6  with numerical values. The right drawing of  FIG. 6  shows the brightness distribution in candela (cd). 
         [0075]    According to  FIG. 5  and  FIG. 6 , it is understood that light is output with almost even brightness both from the side surface as well as from the top surface of the light scattering/guiding globe  10 . A maximum brightness in the right drawing of  FIG. 5  is located at around 4500 (cd), and a maximum brightness in the right drawing of  FIG. 6  exceeds 10,000 (cd). Thus, it is understood that the brightness of the light scattering/guiding globe  10  is higher at the top surface than at the side surface. 
         [0076]    (Regarding a Bulb-Type LED Lamp  1 A According to a Second Embodiment of the Present Invention) 
         [0077]    Explained below is a bulb-type LED lamp  1 A according to a second embodiment of the present invention.  FIG. 7  is a configuration drawing of the bulb-type LED lamp  1 A. The bulb-type LED lamp  1 A is partially different from the bulb-type LED lamp  1 . In the following explanation; any member, which is identical or equivalent to that in the first embodiment, is explained by using the same or similar reference numeral, and then the explanation is omitted or simplified; and on the other hand any member, which is specific to the second embodiment, is mainly explained. 
         [0078]    In the bulb-type LED lamp  1 A, a light scattering/guiding globe  10 A has a circular cylindrical shape. In other words, at least a part of the light scattering/guiding globe  10 A is shaped like a circular cylinder; and an end of the circular cylinder, which is opposite to a side of the LED  11 , is shaped like a convex lens. 
         [0079]    Thus, an outer profile of the light scattering/guiding globe  10 A is circular-cylindrical, being long and thin, and therefore the bulb-type LED lamp  1 A can be installed even in a dug ceiling hole equipped with a small reflector. Furthermore, even without any extra reflector, the bulb-type LED lamp  1 A on its own can evenly radiate light over a wide area, and an objective radiation angle can be adjusted. 
         [0080]      FIG. 8  shows traveling paths of rays of light emitted from the LED  11 . Rays of light, which come in through a first light incoming surface  20 A and a second light incoming surface  21 A, move forward while being multiple-scattered in the light scattering/guiding globe  10 A. Then, they are output from a radiation surface  30 A in a forward direction, a diagonally forward direction, a side direction, and a rearward direction. 
         [0081]    Thus, it is understood that the rays of light radiated from the LED  11  are output in all directions through the light scattering/guiding globe  10 A. 
         [0082]      FIG. 9  is a drawing that corresponds to  FIG. 4 , and it shows a light intensity distribution of output light from the radiation surface  30 A of the bulb-type LED lamp  1 A. It is understood that there exists an almost constant output of light flux within a wide orientation range from 315 degrees to 45 degrees with respect to an optical-axis normal line of the LED  11 . Moreover, light also travels in a rearward direction of the LED  11  as well in the same way as it does in the bulb-type LED lamp  1 . 
         [0083]      FIG. 10  shows a radiated light distribution at a position 1 meter ahead of the top (a part shaped like a lens) of the light scattering/guiding globe  10 A, wherein a view field stretches for 1 meter each upward, downward, rightward, and leftward with its center at the position mentioned above. Meanwhile,  FIG. 11  shows a state of the radiated light distribution, shown in  FIG. 10 , in an area around a 0-mm position while a horizontal axis and a vertical axis representing a distance and a luminous intensity (Unit: Lux), respectively. It is understood that, according to the bulb-type LED lamp  1 A, light is radiated evenly over a wide range as shown in  FIG. 10  and  FIG. 11 . 
         [0084]    (Regarding a Bulb-Type LED Lamp  1 B According to a Third Embodiment of the Present Invention) 
         [0085]    Explained below is a bulb-type LED lamp  1 B according to a third embodiment of the present invention.  FIG. 12  is a configuration drawing of the bulb-type LED lamp  1 B. The bulb-type LED lamp  1 B is partially different from the bulb-type LED lamp  1 . In the following explanation; any member, which is identical or equivalent to that in the first embodiment, is explained by using the same or similar reference numeral, and then the explanation is omitted or simplified; and on the other hand any member, which is specific to the third embodiment, is mainly explained. 
         [0086]    In the bulb-type LED lamp  1 B, a second light incoming surface  21 B is different from the second light incoming surface  21  of the bulb-type LED lamp  1 . Namely, between a bottom plane  22   a  of the first hollow section  22 , being shaped conically, surrounded by the first light incoming surface  20 B and the LED  11 , the second light incoming surface  21 B has a circular shape larger than the bottom plane  22   a  of the conical hollow section. The second light incoming surface  21 B has a concave shape in which a position located further away from the LED  11  toward an outer circumference of the circular shape has a shallower depth, in other words, a distance between the second light incoming surface  21 B and the heat dissipating plate  13  at the position becomes shorter. In the present example case, being combined together, the first hollow section  22  and the second hollow section  24  are shaped both-in-one. 
         [0087]      FIG. 13  shows traveling paths of light that has entered the first light incoming surface  20 B. As shown in  FIG. 13 , the light having collided with the first light incoming surface  20 B travels into the light scattering/guiding globe  10  and moves toward the radiation surface  30  while being multiple-scattered. Then, most of the light is output in a frontward direction of the bulb-type LED lamp  1 B, while some of the light moves in sideward and rearward directions. 
         [0088]      FIG. 14  shows traveling paths of rays of light emitted from the LED  11 , in the light scattering/guiding globe  10 ; wherein the rays of light are those being at a large angle (40 to 90 degrees) in relation to an optical-axis normal line “K”, among all rays of light emitted from the LED  11 . At first, these rays of light enter the second light incoming surface  21 B, and then travel in the light scattering/guiding globe  10  while being multiple-scattered. As described above, the LED  11  and the second light incoming surface  21 B are set in such a way that the rays of light being at a large angle in relation to an optical-axis normal line “K” enter through the second light incoming surface  21 B. 
         [0089]    The rays of light being at a large angle (40 to 90 degrees) in relation to an optical-axis normal line “K” are refracted by the second light incoming surface  21 B so as to enter the light scattering/guiding globe  10  at a less entrance angle in relation to an optical-axis normal line “K.” As a result, an excessive output of light from around a root section of the radiation surface  30  of the light scattering/guiding globe  10  can be controlled so that rays of light are evenly radiated from all over the light scattering/guiding globe  10 . 
         [0090]    Thus, it is understood that, in the bulb-type LED lamp  1 B, rays of light emitted from the LED  11  are output from the radiation surface  30  as outgoing rays of light in all directions by the light scattering/guiding globe  10  equipped with the light incoming surface  20 B and the second light incoming surface  21 B. 
         [0091]      FIG. 15  shows a light intensity distribution of outgoing rays of light from the radiation surface  30  of the bulb-type LED lamp  1 B.  FIG. 15  is a drawing that corresponds to  FIG. 4  and  FIG. 9 . A highest light intensity is observed within an orientation range of +/−45 degrees with respect to the optical-axis normal line “K” of the LED  11 , and it is understood that there exists an almost constant output of light flux in a wide range. 
         [0092]      FIG. 16  shows a brightness of light emission from a side surface of the light scattering/guiding globe  10 . In the meantime,  FIG. 17  shows a brightness of light emission from a top surface of the light scattering/guiding globe  10 . For both  FIG. 16  and  FIG. 17 , a brightness of the light scattering/guiding globe  10  is measured at a position 1 meter away from the light scattering/guiding globe  10 . A right drawing of  FIG. 16  represents the brightness distribution of a left drawing of  FIG. 16  with numerical values. The right drawing of  FIG. 16  shows the brightness distribution in candela (cd). In the meantime, a right drawing of  FIG. 17  represents the brightness distribution of a left drawing of  FIG. 17  with numerical values. The right drawing of  FIG. 17  shows the brightness distribution in candela (cd). 
         [0093]    According to  FIG. 16  and  FIG. 17 , it is understood that light is output with almost even brightness from both the side surface and the top surface. A maximum brightness in the right drawing of  FIG. 16  is located at around 4500 (cd), and a maximum brightness in the right drawing of  FIG. 17  exceeds 10,000 (cd). Thus, it is understood that the brightness of the light scattering/guiding globe  10  is higher at the top surface than at the side surface. 
         [0094]    (Regarding a Bulb-Type LED Lamp  1 C According to a Fourth Embodiment of the Present Invention) 
         [0095]    Explained below is a bulb-type LED lamp  1 C according to a fourth embodiment of the present invention.  FIG. 18  is a configuration drawing of the bulb-type LED lamp  1 C. The bulb-type LED lamp  1 C is partially different from the bulb-type LED lamp  1 A. In the following explanation; any member, which is identical or equivalent to that in the second embodiment, is explained by using the same or similar reference numeral, and then the explanation is omitted or simplified; and on the other hand any member, which is specific to the fourth embodiment, is mainly explained. 
         [0096]    In the bulb-type LED lamp  1 C, a second light incoming surface  21 C is different from the second light incoming surface  21 A of the bulb-type LED lamp  1 A. Namely, between a bottom plane  22   a  of the first hollow section  22 , being shaped conically, surrounded by the first light incoming surface  20 C and the LED  11 , the second light incoming surface  21 C has a circular shape larger than the bottom plane  22   a  of the first hollow section  22 . The second light incoming surface  21 C has a concave shape in which, the further a position is located away from the LED  11  toward an outer circumference of the circular shape, the shorter a distance between the second light incoming surface  21 C and the heat dissipating plate  13  at the position becomes. 
         [0097]      FIG. 19  shows traveling paths of rays of light emitted from the LED  11 . Rays of light, which come in through a first light incoming surface  20 C and a second light incoming surface  21 C, move forward while being multiple-scattered in the light scattering/guiding globe  10 A. Then, they are output from a radiation surface  30 A in a forward direction, a diagonally forward direction, a side direction, and a rearward direction. As shown in  FIG. 19 , it is understood that, in the bulb-type LED lamp  1 C, rays of light emitted from the LED  11  are output in all directions. 
         [0098]      FIG. 20  shows a light intensity distribution of output light from the radiation surface  30 A of the bulb-type LED lamp  1 C. It is understood that there exists an almost constant output of light flux within a wide orientation range of 90 degrees in total on both sides of the optical-axis normal line “K” of the LED  11 . 
         [0099]      FIG. 21  shows a radiated light distribution at a position 1 meter ahead of a top (a part shaped like a lens) of the bulb-type LED lamp  1 C, wherein a view field stretches for 1 meter each upward, downward, rightward, and leftward with its center at the position mentioned above. Meanwhile,  FIG. 22  shows a state of the radiated light distribution, shown in  FIG. 21 , in an area around a 0-mm position while a horizontal axis and a vertical axis representing a distance and a luminous intensity (Unit: Lux), respectively. It is understood that, according to the bulb-type LED lamp  1 C, light is radiated evenly over a wide range as shown in  FIG. 21  and  FIG. 22 . In the meantime, a luminous intensity is somewhat reduced at a central area in  FIG. 21  and  FIG. 22 . The central area corresponds to the luminous intensity at the top (a part shaped like a lens) of the bulb-type LED lamp  1 C, and output light from a side surface and the like of the bulb-type LED lamp  1 C is gathered at the area by a reflector and so on so that no unfavorable condition actually occurs. Incidentally, such a phenomenon is remedied in the case of the bulb-type LED lamp  1 A. 
         [0100]    (Other Modifications) 
         [0101]    Various other modifications may be made on the embodiments of the present invention without departing from the concept of the present invention. In the above embodiments, the LED  11  is described as a white LED. Alternatively, any LED in other colors may be used. Moreover, in the above embodiments, one and only LED is used as the LED  11 . Alternatively, any other structure including a plurality of LEDs  11  may be applied. Such a structure is explained with reference to  FIG. 23 . Shown in  FIG. 23  are a circuit board  12 , three LEDs  11 W,  11 G, and  110  placed on the circuit board  12 , and a dimming controller  40 . The LEDs  11 W,  11 G, and  110  are a white LED, a green LED, and an orange-colored LED, respectively. The three LEDs  11 W,  11 G, and  110  are placed at positions in the vicinity of the installation position of the LED  11  in the embodiments described above (indicated with a dashed line in the drawing). On this occasion, while the LEDs  11 W and  11 G being super luminosity LEDs, the LED  11 O may be a type of LED less-luminous in comparison with the other LEDs  11 W and  11 G. 
         [0102]    The dimming controller  40  corresponds to the power supply section  14  and the like, and it can supply the three LEDs  11 W,  11 G, and  110  individually with electric power. On this occasion, the dimming controller  40  controls either current values or light emission pulse duty ratios for the three LEDs  11 W,  11 G, and  110  so that light emission intensity of the three LEDs  11 W,  11 G, and  110  can individually be controlled. 
         [0103]    Thus, rays of light emitted from the three LEDs  11 W,  11 G, and  110  enter the light scattering/guiding globes  10  and  10 A through the first light incoming surfaces  20 ,  20 A,  20 B, and  20 C as well as the second light incoming surfaces  21 ,  21 A,  21 B, and  21 C of the light scattering/guiding globes  10  and  10 A. Then, the rays of light are multiple-scattered and their colors are mixed within the light scattering/guiding globes  10  and  10 A, and subsequently the light is output from the radiation surfaces  30  and  30 A. 
         [0104]    Thus, while a color temperature of the bulb-type LED lamps  1 ,  1 A,  1 B, and  1 C being changed successively in a range of 2000K to 7000K, homogeneous light can be output from the radiation surfaces  30  and  30 A. 
         [0105]    Still as another modification, 3 LEDs having their light colors corresponding to the three primary colors (Red, Blue, and Green) may be prepared to materialize a bulb-type LED lamp that emits light in various colors according to requests of users by controlling their light emission intensities. 
         [0106]    According to the bulb-type LED lamps  1 ,  1 A,  1 B, and  1 C, light can be output with uniform brightness from an entire area of the light scattering/guiding globes  10  and  10 A without lowering an efficiency of light output. Thus, it becomes possible to reduce the chance of causing a glare or a discomfort feeling on humans. 
         [0107]    Furthermore, according to the bulb-type LED lamps  1 ,  1 A,  1 B, and  1 C, even with the small number of LEDs to be used (for example, even one LED), light can be output with uniform brightness from an entire area of the light scattering/guiding globes  10  and  10 A. Thus, it becomes possible to implement a reduction in power consumption of the bulb-type LED lamps  1 ,  1 A,  1 B, and  1 C. 
         [0108]    Moreover, according to the bulb-type LED lamps  1 A and  1 C, light can uniformly be radiated onto an objective irradiation area with high efficiency by suitably controlling the characteristics of output light distribution of the light scattering/guiding globe  10 A alone. 
         [0109]    According to the modification of the embodiment shown in  FIG. 23 , provided can be a lighting apparatus that is able to change a color temperature of its bulb-type LED lamp in a uniform soft light range from a warm color to a white color by means of changing the light quantity of the LED  11 O, changing the light quantity of the LED  11 W while keeping the LED  11 O unchanged, or changing the light quantities of both the LEDs, wherein one and only bulb-type LED lamp being used.