JP5872658B2 - Light bulb shaped LED light source - Google Patents

Description

  The present invention relates to a bulb-type LED light source.

  In a bulb-shaped light source, the outer bulb glove naturally lowers the transmittance, so it is counterproductive from the viewpoint of luminous efficiency, but when used for general lighting, the brightness of the LED (light emitting diode) is high, In order to suppress this, it is known that an outer tube glove having a milky white light diffusing effect is disposed in front of the LED light source.

  For example, FIG. 7 is a cross-sectional view showing a conventional LED bulb 200. The LED bulb 200 can obtain white light with a simple structure and uniform brightness and a wide irradiation range, and the light distribution pattern can be easily changed, and can be directly connected to a general commercial power source. It is an object to provide an LED bulb that is compatible with incandescent bulbs.

  The LED bulb 200 is provided with a base 201 at one end, a cover 202 that expands in a trumpet shape toward the opening at the other end, and an outer tube globe that is attached to the opening of the cover 202 and has a light diffusion layer 206 on the inner surface. 205, a substrate 203 provided in a substantially spherical body 207 formed by the cover 202 and the outer tube globe 205, and an LED element 204 mounted on the outer surface of the substrate 203 facing the outer tube globe 205. . The outer tube globe 205 may be made of a uniform material (acrylic or the like) having a light diffusion effect.

  Further, the substrate 203 is formed in a plate shape parallel to the outer surface of the opening of the cover 202. That is, a plurality of LED elements 204 are arranged on a planar substrate 203 (see, for example, Patent Document 1).

JP 2001-243807 A JP 2010-073438 A

  In such an LED bulb 200, the light emitted from the LED element 204 is irradiated to the outer tube globe 205, and an area in which the light emitted from the plurality of LED elements 204 partially overlaps or is irradiated. Or come off. That is, there is a problem that uneven brightness occurs.

  Also, since the LED element 204 is installed on the same substrate 203 in the same irradiation direction, unlike a light bulb or a light bulb-type fluorescent lamp, the product shape is like a light bulb, but the light distribution characteristics are completely different. Unlike the spotlight, the irradiation is concentrated in only one direction and the direction perpendicular to the surface of the substrate 203. Conventionally, when an incandescent bulb is used as a light source for a lighting fixture, the illumination distribution in the entire room changes greatly, and generally the ceiling and walls become darker than before replacement.

  Also, when used as a light source for downlights, the light distribution on the wall surface is not considered as important, so there was a tendency to concentrate the light distribution on the axis so that the illuminance directly below is equivalent to that of an incandescent bulb. In this case, since the light distribution in which the vertical component easily diffuses to the central axis, which is likely to be lost in the outer tube globe 205, is relatively reduced, the light emission efficiency is increased, but only the center of the light emitting surface has high brightness, and The brightness uniformity of the image is reduced, there is a problem of unevenness, and the problem that the wall becomes dark is greatly highlighted.

  Further, if the number of n (the number of LED elements 204, n is a natural number) is made extremely large, the above problem seems to be solved. However, in actuality, many LED elements 204 cannot be arranged on the surface of the substrate 203 having a finite area, the productability is reduced in terms of cost, the temperature becomes too high, and the life of the LED elements 204 is shortened. The long-life characteristic that is assumed to be greatly sacrificed.

  If the transmittance of the outer tube globe 205 is lowered and the diffusibility is increased, the luminance uniformity is improved. However, this reduces the luminous efficiency of the lamp itself.

  As a factor that influences the light emission efficiency, almost all of the light enters the filter medium and passes through the filter for diffusion (outer tube globe 205) perpendicular to the irradiating optical axis while being attenuated. This is called linear transmittance. However, if the optical axis enters at an angle with respect to the filter, a part of the light does not enter the filter medium and is reflected. In the case of the LED bulb 200, the light reflected in the outer tube globe 205 is further reflected in multiple, and is divided into one that is irradiated to the outside of the outer tube globe 205 and one that is lost in the outer tube globe 205. That is, in the outer tube globe 205 having a portion that is not perpendicular to the optical axis, the internal loss increases and the overall luminous efficiency decreases as the portion with a smaller incident angle increases. Therefore, if a plurality of LEDs having a narrow light distribution angle are arranged in a plane and a plane diffusion plate perpendicular to all the LED optical axes is installed, the loss is reduced, but the performance as an alternative to an incandescent bulb is reduced.

  If LED light bulbs 200 become widespread and products with many light distribution patterns are developed in the future, users can select products according to their applications. However, due to restrictions on sales volume, cost, and actual selling price for the time being, there are practically no light distribution patterns in the product, and the design policy is mainly to make the illuminance directly below that of existing incandescent bulbs. ing. We examined the optimal balance between the “direct illuminance”, “distribution to the wall”, and “luminance uniformity of the light source itself (low luminance unevenness)”. Therefore, it is not intended to increase the efficiency of the LED element 204 or to add light distribution to the wall while maintaining the illuminance directly below, but to optimize the current total light amount distribution method and expand its application It was.

  The present invention provides a bulb-type LED light source that can reduce unevenness of light.

  In addition, a design means for appropriately changing the light distribution angle of a plurality of LED elements to be used can be considered. However, using this method creates an industrially complicated process, and the total number of LED elements used is the same. Since it is divided into two types, the mass productivity is reduced, the cost is increased, and the lead time for preparing the member is extended. Therefore, it is assumed that this method is not used.

  Furthermore, it is conceivable to change the optical axis of each LED element without changing the light distribution angle, and although we have commercialized it as PARATHOM CLASSIC A, it is not possible to install LEDs directly on a single substrate surface. From the industrial point of view, it was a problematic method, so it was removed from the study.

  Therefore, when solving this problem, the design method used is that all LED elements have the same light distribution angle, no complicated identification or use is required, and the LED elements are installed on the substrate in the same irradiation direction, and all the optical axes are on the substrate. Limited to designs that are only perpendicular to the surface.

  The design should preferably have a uniform light distribution in the lower hemisphere, and even the same light distribution in the upper hemisphere, but in reality there are no LED elements that can satisfy these requirements, and we Decided to design a light distribution that is as uniform as possible in the lower hemisphere, and to some extent also in the illumination directly below.

  The linear transmittance of the outer tube glove was about 90%. However, this transmittance is an event essentially independent of the present invention, and the effect of the present invention is not limited to 90%.

  As shown in FIG. 8, the light distribution angle of the LED element is such that when the light quantity on the central axis is 100%, the light quantity is on the central axis line when the LED emission center is viewed at a certain angle from the central axis. It is a two-dimensional angle from the central axis until it is reduced to 50%. That is, the angle is centered on the central axis and decreases to 50% on both sides of the central axis. Accordingly, although the light is actually radiated to the outside of this area, the area inside the light distribution angle of the LED element is defined as a light distribution area in order to clarify the design verification.

The light bulb shaped LED light source according to the present invention is
An outer tube glove having a light diffusion layer;
A substrate provided inside the outer tube globe;
N light sources mounted on one surface of the substrate facing the outer tube globe,
Each light source of the n light sources has a light distribution angle of 60 ° or more and 120 ° or less, and an area inside the light distribution angle is a light distribution area.
The central axis of the light distribution angle of each of the n light sources is a direction perpendicular to the one surface of the substrate,
In the inner surface of the outer tube globe, the 0-fold area that is removed from any light distribution area of the n light sources is 30% or less of the inner surface of the outer tube globe.

The light bulb shaped LED light source according to the present invention is
The n-fold light distribution area where the n light distribution areas of the n light sources overlap is 10% to 80% of the inner surface of the outer tube globe.

  The light bulb shaped LED light source according to the present invention can improve the luminance uniformity on the outer tube globe, that is, reduce light unevenness, without reducing the efficiency, by the above configuration.

FIG. 2 shows the first embodiment, and is a side view (a) and a front view (b) of a light bulb shaped LED light source 100. FIG. FIG. 5 shows the first embodiment, and shows the light distribution characteristics of the light bulb-type LED light source. FIG. 5 shows the first embodiment and is a schematic diagram showing a light distribution area in the outer tube globe when the number of LED elements is n = 3. FIG. 5 shows the first embodiment and is a schematic diagram showing a light distribution area in the outer tube globe when the number of LED elements is n = 4. FIG. 5 shows the first embodiment, and is a schematic diagram showing a light distribution area in an outer tube globe when the number of LED elements is n = 5. The figure which shows the design parameter and evaluation result of Comparative Examples 1-7 and Examples 1-4. Sectional drawing which shows the conventional LED bulb 200. The figure which defines the light distribution angle of an LED element.

Embodiment 1 FIG.
FIGS. 1 to 6 are diagrams showing Embodiment 1, FIG. 1 is a side view (a) and a front view (b) of a bulb-type LED light source 100, and FIG. 2 is a diagram showing light distribution characteristics of the bulb-type LED light source. FIG. 3 is a schematic diagram showing a light distribution area in the outer tube globe when the number of LED elements n = 3, and FIG. 4 is a schematic diagram showing a light distribution area in the outer tube globe when the number of LED elements n = 4. FIG. 5 is a schematic diagram showing a light distribution area in the outer tube globe when the number of LED elements is n = 5, and FIG. 6 is a diagram showing design parameters and evaluation results of Comparative Examples 1-7 and Examples 1-4. It is.

  As shown in FIG. 1, the bulb-type LED light source 100 is provided with a base 1 at one end and a metallic heat dissipating component 2 that expands in a trumpet shape toward the opening at the other end. The heat dissipating component 2, the outer tube glove 5 attached to the opening of the heat dissipating component 2 and having the light diffusion layer 6 on the inner surface, and the substantially spherical body 7 formed by the heat dissipating component 2 and the outer tube glove 5 are provided. The board | substrate 3 and the LED element 4 mounted in the outer surface facing the outer tube | pipe globe 5 of this board | substrate 3 are provided.

The light bulb shaped LED light source 100 in the present embodiment has the following characteristics.
(1) The LED element 4 (light emitting diode) is used as a light source.
(2) It has a light bulb-shaped appearance (see FIG. 1).
(3) A light source with a built-in lighting circuit that does not have a wide light distribution like a light bulb and can be lit by a commercial power source that projects light in a range of about 2πStRad (steradian).
(4) An outer bulb globe which is an incandescent bulb alternative light source having an E base or an E base such as E26 base or B base specified in JIS C7709-1, and further imitating an incandescent bulb in front of an LED light source 5 is a light bulb shaped LED light source 100.
(5) The LED elements 4 are arranged in a plane on the substrate 3 in at least n (natural number of 4 or more) outer tube globes 5.
(6) Each LED element 4 has a light distribution characteristic (light distribution angle) of at least 60 ° to 120 ° (see FIG. 2 and FIG. 8 for the light distribution angle). Incidentally, the LED element 4 of 120 ° or more has a wide light distribution angle, and the illumination angle is too wide as a light source using the outer tube globe 5, and the problem of uneven brightness is not important in the first place, but the outer tube globe 5 is not important. Loss is large, the efficiency as a light source is low, and the illuminance directly below is difficult to increase.
(7) A light distribution area where each LED element 4 distributes light on the inner surface of the outer tube globe 5 is overlapped.
(8) The overlap has n light distribution areas in part, and the light distribution area overlapping n layers is 10% or more of the inner surface of the outer tube globe 5.
(9) The area deviating from the light distribution area of any LED element 4 (hereinafter referred to as 0-fold) is less than 30% of the inner surface of the outer tube globe 5.

In the conventional LED bulb 200, when the cause of the uneven brightness in the outer tube globe 205 was investigated, it was found that the uneven brightness occurred for the following two reasons.
(1) Although light emitted from a specific LED element 204 is irradiated with a specific light distribution angle, the distance from each LED element 204 to the inner surface of the outer tube globe 205 within the irradiation range is different.
(2) There are areas where light emitted from a plurality of LED elements 204 is superimposed and areas where light is not superimposed.

  As a result of a series of investigations by the inventors, it has been found that the former (1) has a relatively small influence on light unevenness compared to the latter (2).

  In addition, a series of studies revealed that unevenness is relatively unnoticeable when the light distribution overlap is point-symmetric.

  The inventors studied the latter (2) in order to improve the luminance uniformity of the outer tube globe 5. The result is shown in FIG. In addition, Comparative Example 1 (1) to Comparative Example 6 (6) and Examples (7) to (9) in FIG. 6 are the same as (1) to (9) and Example (11) in FIGS. This corresponds to (11) in FIG. About the comparative example 7 (10) of FIG. 6, the schematic which shows the light distribution area in the corresponding outer tube | pipe glove 5 is abbreviate | omitted. In the schematic view showing the light distribution area of Comparative Example 6 (6) in (6) in FIG. 4, the LED elements 4 arranged at concentric circles are centered.

  The light radiated from the n LED elements 4 generates a maximum n-fold light distribution area. Depending on the arrangement of the LED elements 4 and the selection of the light distribution angle, there may be a case where the overlap is less than n times at most. Here, since the distance between the LED element 4 and the inner surface of the outer tube globe 5 can only be in a very limited range and cannot cause a large difference, the inner surface of the outer tube globe 5 irradiated from the LED element 4 Luminance tended to be governed by the number of light distribution areas rather than the difference in distance.

  Further, when the luminance gradually decreased from the center of the outer tube globe 5 toward the peripheral portion, it was difficult to recognize as luminance unevenness, that is, no discomfort was felt for the luminance gradient. Therefore, regarding the brightness uniformity in the survey, sensory evaluation on the brightness unevenness felt when actually looking at the light source, rather than measuring many brightnesses on the outer tube globe 5 of one light source and numerically grasping the variation. The case where the subject feels unpleasant is evaluated as x, the case where the subject feels slightly unpleasant is evaluated as △, and the case where there is no problem is evaluated as ○. Designed as the market satisfaction level in the area of ○.

  Therefore, in order to increase the luminance uniformity, the LED element 4 having a large light distribution angle is selected, the number n of the LED elements 4 is increased, and the center of the substrate 3 and / or the center of the substrate 3 is concentric with the center. It is important to place it on top and narrow the 0-fold area. On the other hand, in order to increase the illuminance directly below, it is important to provide an n-fold light distribution area on the axis of the lamp (bulb-shaped LED light source 100). In order to increase the luminous efficiency of the entire lamp, it is important to use an LED element 4 having a light distribution angle as narrow as possible.

  In order to balance these mutually contradicting propositions and realize customer satisfaction, the number n (n is a natural number) of the LED elements 4 is preferably at least 4. As shown in FIG. 3, when the number n of the LED elements 4 is 3, the LED element 4 having a very wide light distribution angle is required, the loss in the outer bulb glove 5 is increased, and the entire lamp (bulb-shaped LED light source 100) emits light. The efficiency is not satisfactory.

  In addition, when the number n of LED elements 4 is 3, if the luminance uniformity and point symmetry are incorporated in the design, the arrangement is as shown in FIG. 3, and it is difficult to overlap the central portion and the illuminance directly below cannot be increased. . Therefore, n is preferably 4 or more. In the example of 90 ° with n = 3 raised in the comparative example, a light distribution area of n = triple is generated at the center, but it was not possible to achieve both brightness uniformity and satisfactory direct illuminance.

When the irradiation angle is wide, it is easy to create an n-fold light distribution area, but on the other hand, the loss of irradiation outside the outer tube globe 5 increases, so the light distribution angle (θ _{1 in} FIG. 2) is desirably 120 ° or less. In addition, if the irradiation angle is too narrow, an n-fold area is difficult to be generated. Therefore, the light distribution angle is preferably 60 ° or more.

  Increasing the illuminance directly below is also an important design factor, and at least the outer bulb glove 5 on the center line of the lamp (bulb-shaped LED light source 100) should have n light distribution areas.

  In addition, the n-fold light distribution area on the outer tube globe 5 does not occupy 10% or more of the whole, and a substantially satisfying direct illuminance cannot be obtained. On the other hand, if the LED elements 4 are arranged at concentric circles, it is difficult to perceive luminance unevenness when visually observed.

  As the LED elements 4, general white LED elements, each of which outputs 100 lm at a rated power consumption of 1 W per element, in combination with a blue LED and a yellow light emitting phosphor, are used. Then, five types of light distribution angles with different light distribution angles of 30 °, 60 °, 90 °, 120 °, and 150 ° are prepared, and one element is provided in the center on the printed circuit board 3 having a diameter of 55 mm shown in FIG. In some cases, a plurality of LED elements 4 are arranged concentrically from the center of the substrate 3 at a point-symmetrical position around the periphery, and an E26 cap type bulb-type LED lamp (bulb-shaped LED light source 100) is prototyped. Comparative evaluation was performed.

  Although not specifically described, since the temperature of the substrate 3 rises, a sufficient heat dissipation medium is provided on the base 1 side from the substrate 3. Further, as the prototype lamps, glass white outer tube globes 5 each having a linear transmittance of 90% and a diameter of 60 mm and having an inner surface of outer tube globe 5 shown in FIG.

  In order to compare the 0-fold area as a parameter, a prototype was created by changing the ratio of the 0-fold area with the radius of the concentric circle. Although the number n of the LED elements 4 is different, all of them were lit at rated power. Of course, if the number n of the LED elements 4 is large, the total luminous flux of the completed lamp itself becomes large. However, in this experiment, the total luminous flux was not unified, but was normalized by the number n of the LED elements 4 (that is, rebate relative evaluation with W). Therefore, in the case of one element, 1 W (however, the power loss is excluded from the calculation), and in the case of five elements, 5 W of electric power is input to the LED element 4.

  In order to compare the efficiency, the number of LED elements 4 used is n, and the theoretical efficiency when the outer tube transmittance is 0.9 (unit: lm / W): rated output 100 (lm / element) × n (element) /N(W)×0.9 (outer tube transmittance) was 100%, and the total luminous flux value of the prototype lamp was measured with an integrating sphere and indicated as a relative value.

  Of course, higher efficiency is desirable, and we considered 90% or better. The uneven brightness on the outer bulb 5 is called brightness uniformity. It is desirable that the brightness is uniform everywhere. However, unlike a bulb-type fluorescent lamp having a fluorescent lamp as a light source, it is a high-intensity minimal light source. In addition, since there is a light distribution angle, it is practically impossible to obtain uniform brightness on the outer tube globe 5. The user's satisfaction changes depending on how this is balanced.

  In addition, regarding the illuminance directly below, the prototype lamp was turned on with the base up, and the illuminance of 1 m immediately below the lamp was measured with an illuminometer, and each measured illuminance was divided by the total wattage of the lamp. That is, if the direct illuminance of 4 W using the four LED elements 4 is 52 lx, the direct illuminance is 52/4 = 13 (lx / W). The illuminance immediately below is generally a value of 10 (lx / W) or more. Of course, if this is the same design, it will increase in proportion to the total power consumption of the lamp, and in order for the user to obtain the necessary illuminance, should the wattage of the bulb-type LED lamp (bulb-type LED light source 100) be adjusted? Or the number of lamps used will be adjusted.

  In the embodiment, one LED element 4 is arranged at the center of the substrate 5, but it is not always necessary to arrange it at the center. Further, the transmittance of the outer tube globe 5 is not limited to 90%, and the material may be made of resin other than glass. The arrangement of the LED elements 4 was concentric for the purpose of comparison.

As described above, the bulb-type LED light source of this embodiment is
A lighting circuit that uses an LED (light emitting diode) element as a light source, has a light bulb-like appearance, does not have a wide light distribution like a light bulb, and can be lit by a commercial power source that projects light in a range of about 2πSt (steradian) In a built-in light source, which is an alternative to an incandescent light bulb having an E or B base, and further having an outer bulb globe simulating an incandescent bulb on the front of the LED light source,
The LED elements are arranged on the same plane of a substantially flat substrate in the outer tube globe with at least n (natural number of 4 or more) elements,
Each LED element has a light distribution angle of at least 60 ° to 120 °, and a central axis of the light distribution angle is perpendicular to the substantially planar substrate surface,
While each LED element makes the light distribution area inside the light distribution angle that irradiates light to the inner surface of the outer tube globe overlap,
The overlap has the light distribution area of n layers in a part including the inner surface of the outer tube bulb on the center axis of the lamp, and the light distribution area of n layers is 80% or more of the inner surface of the outer tube globe 80 % Or less.

  Moreover, the said area removed from the light distribution area of any said LED element is less than 30% of the said outer tube | glove inner surface.

  1 Base, 2 Cover, 3 Substrate, 4 LED Element, 5 Outer Globe, 6 Light Diffusing Layer, 7 Sphere, 100 Light Bulb Shape LED Light Source, 200 Light Bulb Shape LED Light Source, 201 Base, 202 Cover, 203 Board, 204 LED Element, 205 outer tube globe, 206 light diffusion layer, 207 substantially spherical.

Claims (10)

An outer tube glove having a light diffusion layer;
A substrate provided inside the outer tube globe;
N light sources mounted on one surface of the substrate facing the outer tube globe,
Each light source of the n light sources has a light distribution angle of 60 ° or more and 120 ° or less, and an area inside the light distribution angle is a light distribution area.
The central axis of the light distribution angle of each of the n light sources is a direction perpendicular to the one surface of the substrate,
In the inner surface of the outer tube globe, said n 0 fold areas deviating from any of the light distribution area of the light source state, and are 30% or less of the inner surface of the outer tube globe,
The bulb-type LED light source characterized in that an n-fold light distribution area in which n light distribution areas of the n light sources overlap is 10% or more and 80% or less of the inner surface of the outer tube globe . An outer tube glove having a light diffusion layer;
A substrate provided inside the outer tube globe;
N light sources mounted on one surface of the substrate facing the outer tube globe,
Each light source of the n light sources has a light distribution angle of 60 ° or more and 120 ° or less, and an area inside the light distribution angle is a light distribution area.
The central axis of the light distribution angle of each of the n light sources is a direction perpendicular to the one surface of the substrate,
In the inner surface of the outer tube globe, said n 0 fold areas deviating from any of the light distribution area of the light source state, and are 30% or less of the inner surface of the outer tube globe,
When the theoretical efficiency when the transmittance of the outer tube globe is 0.9 is 100%, the luminous efficiency is 90% or more,
A bulb-type LED light source characterized by having an illuminance of 10 lx / W or more at 1 m directly below . An outer tube glove having a light diffusion layer;
A substrate provided inside the outer tube globe;
N light sources mounted on one surface of the substrate facing the outer tube globe,
Each light source of the n light sources has a light distribution angle of 60 ° or more and 120 ° or less, and an area inside the light distribution angle is a light distribution area.
The central axis of the light distribution angle of each of the n light sources is a direction perpendicular to the one surface of the substrate,
In the inner surface of the outer tube globe, said n 0 fold areas deviating from any of the light distribution area of the light source state, and are 30% or less of the inner surface of the outer tube globe,
The n light sources are four or more LED elements . n light sources;
An outer bulb glove arranged in front of the n light sources and imitating a light bulb;
A substrate in which the n light sources are arranged on a planar substrate surface,
The n light sources have a light distribution angle of 60 ° or more and 120 ° or less,
A central axis of the light distribution angle of the n light sources is perpendicular to the substrate surface;
Said n light sources the light distribution angle inside the light distribution 0 duplex area departing from any of the light distribution area for the area of the of state, and are 30% or less of the inner surface of the outer tube globe,
The light distribution area inside the light distribution angle of the n light sources has an n light distribution area that overlaps n times on the inner surface of the outer tube globe,
The bulb-type LED light source characterized in that the n-fold light distribution area occupies 10% to 75% of the inner surface of the outer tube globe . n light sources;
An outer bulb glove arranged in front of the n light sources and imitating a light bulb;
A substrate in which the n light sources are arranged on a planar substrate surface,
The n light sources have a light distribution angle of 60 ° or more and 120 ° or less,
A central axis of the light distribution angle of the n light sources is perpendicular to the substrate surface;
Said n light sources the light distribution angle inside the light distribution 0 duplex area departing from any of the light distribution area for the area of the of state, and are 30% or less of the inner surface of the outer tube globe,
When the theoretical efficiency when the transmittance of the outer tube globe is 0.9 is 100%, the luminous efficiency is 90% or more,
A bulb-type LED light source characterized by having an illuminance of 10 lx / W or more at 1 m directly below . n light sources;
An outer bulb glove arranged in front of the n light sources and imitating a light bulb;
A substrate in which the n light sources are arranged on a planar substrate surface,
The n light sources have a light distribution angle of 60 ° or more and 120 ° or less,
A central axis of the light distribution angle of the n light sources is perpendicular to the substrate surface;
Said n light sources the light distribution angle inside the light distribution 0 duplex area departing from any of the light distribution area for the area of the of state, and are 30% or less of the inner surface of the outer tube globe,
The n light sources are four or more LED elements . The bulb-type LED light source has four light sources,
The n light sources have a light distribution angle of 60 °,
The n-fold light distribution area is 10% of the inner surface of the outer tube globe,
The bulb-type LED light source according to claim 4, wherein the 0-fold area is 30% of the inner surface of the outer tube globe. The bulb-type LED light source has four light sources,
The n light sources have a light distribution angle of 90 °,
The n-fold light distribution area is 20% of the inner surface of the outer tube globe,
The bulb-type LED light source according to claim 4, wherein the 0-fold area is 12% of the inner surface of the outer tube globe. The bulb-type LED light source has four light sources,
The n light sources have a light distribution angle of 120 °,
The n-fold light distribution area is 75% of the inner surface of the outer tube globe,
The bulb-type LED light source according to claim 4, wherein the 0-fold area is 5% of the inner surface of the outer tube globe. The bulb-type LED light source has five light sources,
The n light sources have a light distribution angle of 90 °,
The n-fold light distribution area is 15% of the inner surface of the outer tube globe,
The bulb-type LED light source according to claim 4, wherein the 0-fold area is 15% of the inner surface of the outer tube globe.

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