EP2778504A1

EP2778504A1 - Straight-Tube LED Lamp, and Lighting Device

Info

Publication number: EP2778504A1
Application number: EP14158916.8A
Authority: EP
Inventors: Masahiro Uchiyama; Nobuaki Ono
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2013-03-11
Filing date: 2014-03-11
Publication date: 2014-09-17
Also published as: JP2014175207A

Abstract

A straight-tube LED lamp (100) includes an elongated-shaped casing (2) which has two edges along a longitudinal direction; a translucent cover member (3) which is attached to the casing so as to cover the edges of the casing throughout in the longitudinal direction; and a plurality of semiconductor light-emitting devices (12a, 12b) which are arranged in the cover member along the longitudinal direction as a light source, wherein on an inner surface side of the cover member, the cover member has one or more lens surfaces (50, 52) which reduce an apparent area of the light source.

Description

The present invention relates to a straight-tube LED lamp using a semiconductor light-emitting device such as an LED, or the like as a light source, and a lighting device including the straight-tube LED lamp.
Recently, a straight-tube LED lamp using an LED (Light-Emitting Diode) as a light source has been commercialized.
Light-emitting efficiency of an LED for lighting has been improving since its practical realization.
Due to the developments in LED manufacturing technology, not only transition from an incandescent light bulb to a straight-tube LED lamp but also transition from a fluorescent lamp (fluorescent tube) to a straight-tube LED lamp have been proposed and implemented.
Compared to the fluorescent tube, the straight-tube LED lamp has more advantages such as a longer life, lower power consumption, a lower impact on the environment by non-use of mercury, and so on.
As general commercial fluorescent lamps (fluorescent tubes), there are a ring-shaped circular-tube fluorescent lamp, and an elongated-shaped straight-tube fluorescent lamp.
The circular-tube fluorescent lamp is mainly used in households, and the straight-tube fluorescent lamp is widely used for the purposes of factory use, office use, general household use, and so on.
The straight-tube LED lamp, which has been replacing the straight-tube fluorescent lamp, has a transparent cover and a metal frame, and includes a built-in LED unit having an LED substrate on which a plurality of LEDs are mounted in the longitudinal direction in the transparent cover and the metal frame.
However, because an LED has a characteristic of high directivity, it is disadvantageous in that lighting using an LED as a light source is extremely bright, and discomfort glare (discomfort caused by glare) increases easily.
As an index which evaluates discomfort glare, there is the UGR (Unified Glare Rating) provided by JIS (Japanese Industrial Standards).
In order to reduce a value of the UGR, a method of reducing a luminance value of a light source, and reduction of an apparent area of a light source as seen from an observer's side are effective.
As to reduction of the luminance value, a method of using a prism sheet disclosed in Japanese Patent Application Publication No. 2012-114081 , and so on are known.
As a method of reducing an apparent area of a light source as seen from an observer's side, a method of adjusting a position of a luminaire (light fixture) disclosed in Japanese Patent Application publication No. H011-134905 , and the like are already known.
However, conventional methods of reducing an apparent area of a light source mostly involve adjustment of a position of a luminaire, change and improvement of a shape of the luminaire, and so on, and there has been no solution that reduces a value of the UGR as a lamp itself.
If a lamp itself has a function of reducing a value of the UGR, it is possible to effectively use an existing device (luminaire), and contribute to improvement of usability without problems of adjusting a position.
A main object of the present invention is to provide a straight-tube LED lamp that reduces an apparent area of a light source without relying on a shape of a luminaire, and reduces glare by reducing a value of the UGR.
In order to achieve the above object, an embodiment of the present invention provides a straight-tube LED lamp comprising: an elongated-shaped casing which has two edges along a longitudinal direction; a translucent cover member which is attached to the casing so as to cover the edges of the casing throughout in the longitudinal direction; and a plurality of semiconductor light-emitting devices which are arranged in the cover member along the longitudinal direction as a light source, wherein on an inner surface side of the cover member, the cover member has one or more lens surfaces which reduce an apparent area of the light source.

FIG. 1 is a cross-sectional diagram of a main part illustrating a structure of a cover of a straight-tube LED lamp according to a first example of an embodiment of the present invention.
FIG. 2 is a diagram that explains the reason a value of the UGR (Unified Glare Rating) is reduced by forming a concave cylindrical lens surface on a cover.
Each of FIG. 3A and 3B is an image of a comparison experiment between a structure that reduces the value of the UGR and a structure that does not reduce the value of the UGR.
FIG. 4 is a cross-sectional diagram of a main part illustrating a structure of a cover of a straight-tube LED lamp according to a second example of the embodiment of the present invention.
FIG. 5 is an enlarged perspective diagram of a part where a concave cylindrical lens surface is formed in the second example.
FIG. 6 is an exploded perspective diagram of a lighting device according to the embodiment of the present invention.
FIG. 7 is a perspective diagram illustrating a state where a cover of a straight-tube LED lamp is removed.
FIG. 8 is a perspective diagram illustrating a state where a part of a casing of a straight-tube LED lamp is cut, and bases are removed.
Each of FIGs. 9A and 9B is a diagram illustrating a structure of a straight-tube LED lamp. FIG. 9A is an exploded perspective diagram of one end with a partial cutout. FIG. 9B is an exploded perspective diagram of the other end with a partial cutout.
Each of FIGs. 10A and 10B is a diagram illustrating a mounting structure of an LED substrate. FIG. 10A is an exploded perspective diagram of one end. FIG. 10B is an exploded perspective diagram of the other end.
FIG. 11 is a diagram of a straight-tube LED lamp as seen from a direction of an arrow A in FIG. 7.
FIG. 12 is an enlarged perspective diagram of a dotted-circle part B in FIG. 8.
FIG. 13 is a cross-sectional diagram of a main part illustrating a fixing structure of a power source substrate with respect to a casing by a clamp.
FIG. 14 is a diagram of a modified example equivalent to FIG. 11.

Hereinafter, each example of an embodiment of the present invention will be explained with reference to the drawings.
Based on FIGs. 1 to 3, a first example will be explained.
Firstly, based on FIGs. 6 to 11, a specific structure of a straight-tube LED lamp and a lighting device according to each example of the embodiment of the present invention will be explained.
FIG. 6 is an exploded perspective diagram illustrating an exterior of a lighting device 200. The lighting device 200 includes a straight-tube LED lamp 100 which has terminals 4a-4d, and a light fixture (luminaire) 150 which has sockets 151a, 151b with holes and to which the straight-tube LED lamp 100 is attached.
The light fixture 150 is the same as that to light a fluorescent lamp, and the terminals 4a-4d of the straight-tube LED lamp 100 coincide with positions of the holes and are inserted into the holes of the sockets 151a, 151b.
Thus, commercial electrical current flows from the terminals 4a-4d to later-described LEDs in the straight-tube LED lamp 100, and the straight-tube LED lamp 100 is lit.
The straight-tube LED lamp 100 is mainly constituted of an elongated-shaped casing 2, a cover 3 as a translucent cover member, and bases 1a, 1b as cap members which are electrically connectable to the light fixture 150.
Here, a transparent cover is used as the cover 3.
The casing 2 is formed such that a cross-section has approximately the same semi-tubular shape (tubular shape) throughout in a longitudinal direction (an axial direction).
The casing 2 has two edges along the longitudinal direction.
In order to improve a function of heat radiation of the heat generated inside, an outer surface of the casing 2 has roughness (see FIG. 11), and thus a surface area of the outer surface of the casing 2 is enlarged.
The casing 2 is formed of a metal material having a large thermal conductivity. Because of its tubular shape, it is possible to inexpensively make a casing 2 having a uniform cross-sectional shape by processing methods such as extrusion molding, pultrusion molding, and the like.
As the metal material, an aluminum alloy or a magnesium alloy is mostly used; however, other extrusion materials, or the like also may be used.
It is possible to provide the same heat radiation function as having a rib or a heat radiation fin by roughness on an outer surface.
Here, in order to improve heat radiation performance, on the outer surface of the casing 2, roughness is provided; however, if electrical insulation between the casing 2 and a later-described drive substrate (power source substrate) and an electrical component is ensured, roughness can be provided on an inner surface.
The cover 3 has approximately the same external diameter (curvature), and is formed in a semi-tubular shape having an opening along the longitudinal direction of the casing 2.
That is, a cross-section of the cover 3 has a circular arc shape, and the size of the cover 3 is as large as to cover the edges of the casing 2 throughout in the longitudinal direction.
As illustrated in FIG. 11, the cover 3 is attached to the casing 2 such that edges 33 of the cover 3 are fitted in grooves 21 which extend in the axial direction and are provided on the outer surface of the edges of the casing 2, and thus the casing 2 and the cover 3 are integrally formed to be in a circular-tube shape.
As illustrated in FIG. 6, the bases 1a, 1b are each provided at either end in the longitudinal direction of the integrally-formed casing 2 and cover 3 so as to cover an outer surface thereof.
As illustrated in FIGs. 9A and 9B, the bases 1a, 1b are equipped with the terminals 4a-4d attachable to a light fixture (light fixture for a fluorescent lamp) 150 that enables the fluorescent lamp to light.
Electrical current is supplied to a power source substrate 7 via the terminals 4a-4d of the bases 1a, 1b, and lead wires 6a, 6b which extend from a connector 16 connected to the bases 1a, 1b.
There is no problem electrically connecting the terminals 4a-4d and the lead wires 6a, 6b by methods of direct soldering, and the like.
The bases 1a, 1b are fixed to the casing 2 by a plurality of screws 5a-5d, and therefore, the bases 1a, 1b integrally enclose the casing 2 and the cover 3 fitted in the casing 2.
The bases 1a, 1b can be fixed to the casing 2 not by screws but fixers such as swages, or the like. A shape of the bases 1a, 1b is approximately the same as that of bases which are each located at either end of an existing fluorescent lamp.
Therefore, in place of a fluorescent lamp, by attaching a straight-tube LED lamp to an existing light fixture using a fluorescent lamp, without replacement of a light fixture, it is possible to make up a light fixture of an LED lamp.
Thus, compared to a case of attaching another new light fixture, it is possible to considerably reduce the equipment and construction cost, and realize a reduction in labor for replacement and reduction in time.
As illustrated in FIG. 11, in the inside of the integrally-formed casing 2 and cover 3, the casing 2 includes a flat part 32.
On an outer side (a lower side in the drawing) of the flat part (part equivalent to a chord of a semicircle shape) 32 of the casing 2 and in the cover 3, an LED substrate 11 as a mounting substrate is fixed via a sheet 10 having adhesiveness to be opposite to the cover 3.
A material of the sheet 10 is preferably a material having a high heat conductivity (for example, a radiator silicon rubber, and so on) to easily conduct heat generated by an LED to the casing 2, that is, to stimulate heat radiation.
In the casing 2, the power source substrate 7 is arranged on an inner side (an upper side in the drawing) of the flat part 32.
As illustrated in FIG. 7, the LED substrate 11 is a printed substrate in an elongated-rectangular shape, and includes an LED substrate 11a and an LED substrate 11b.
The sheet 10 is divided in the longitudinal direction corresponding to a divided structure of the LED substrate 11.
On the LED substrates 11a, 11b, a plurality of LEDs 12a and a plurality of LEDs 12b are mounted at predetermined intervals in the longitudinal direction of the casing 2, respectively, as an example of a semiconductor light-emitting device having an EL (Electro-Luminescence) effect.
FIG. 8 is a perspective view of the straight-tube LED lamp 100 in which the casing 2 is cut along a line C-C in FIG. 11, and the bases 1a, 1b are removed.
As illustrated in FIG. 8, the power source substrate 7 is formed in an elongated-rectangular shape extending in the longitudinal direction of the casing 2, and on its mounting surface, a plurality of electronic components 9 for DC (Direct Current) power source conversion are mounted in the longitudinal direction at intervals.
The electrical current rectified by the electronic components 9 is supplied to the LED substrates 11a, 11b as the mounting substrates through the lead wires 13a, 13b as illustrated in FIG. 10A.
Not-illustrated lead wire, jumper wire, and the like electrically connect between the LED substrate 11a and the LED substrate 11b.
In the present embodiment, the configuration of mounting substrates (LED substrates) mounting a semiconductor light-emitting device is a series arrangement of two mounting substrates; however, the configuration may be a series arrangement of one mounting substrate, or equal to or more than three mounting substrates, or may be a parallel arrangement.
Hereinafter, a specific structure of the embodiment of the present invention will be explained.
As illustrated in FIG. 1, in a center part in a lateral direction perpendicular to the longitudinal direction on an inner surface side of the cover 3, a lens surface 50 is formed by integral molding.
In other words, in a portion of the cover 3 linearly opposite to the LED 12 as a light source, the lens surface 50 which reduces an apparent area of the light source is formed by integral molding.
The lens surface 50 has a concave cylindrical lens shape having power only in the lateral direction.
The lens surface 50 is formed throughout in the longitudinal direction corresponding to the length of the LED substrate 11.
Note that in other drawings, the lens surface 50 of the cover 3 is omitted.
With the above cover structure, it is possible to reduce an apparent area of a light source, and a value of the UGR.
Therefore, it is possible to reduce glare to a person who observes light from the straight-tube LED lamp 100.
Based on FIG. 2, the reason why it is possible to reduce the value of the UGR by forming the lens surface 50 will be explained.
What is observed as luminance may be regarded as approximately parallel light incident onto a light-receiving surface.
In FIG. 2, in a case without a cylindrical lens CR, the size of the LED 12 is directly observed (length b).
In a case with a cylindrical lens CR, it is possible to obtain an effect equivalent to observing "a light-emitting surface a in which an observed region is enlarged".
This means that it is possible to reduce an apparent area of a light source (LED 12).
FIGs. 3A and 3B are image diagrams showing an experiment in which luminance distribution is observed from the front of the cover 3 in a case where a concave lens processing is not performed on a transparent glass material (cover), and a case where the concave lens processing is performed on the transparent glass material, respectively.
In the case where the concave lens processing is performed (FIG. 3B), the luminance distribution is reduced in the lateral direction.
Evaluation of discomfort glare in a luminous environment is performed by the following calculation formula based on a value of the UGR (Unified Glare Rating)
Details of a calculation method of the value of the UGR are defined by the CIE (Commission Internationale de l'Éclairage) 117-1995. $UGR = 8 \log (\frac{0.25}{L_{b}} \cdot Σ L \frac{{^{2}}_{ω}}{P})$

where
L_b: background luminance [cd/m²],
L: luminance of a light-emitting part of each light fixture received by an observer [cd/m²],
ω : a solid angle of a light-emitting part of each light fixture as seen from an observer [sr], and
P: a Guth position index of each light fixture.
As is clear from the above calculation formula, as an area of a light source is smaller, a value of the UGR becomes smaller.
For example, considering a case where an area of a light source is reduced to 1/2.

In this case, as shown in Table 1, it turns out that in the calculation formula of the UGR, the solid angle ω becomes smaller, and a value of the UGR becomes smaller.

[Table 1]

TOTAL LIGHT FLUX	2084	2084
BACKGROUND LUMINANCE (Lb)	13.6	13.6
AREA OF LIGHT SOURCE (A)	0.014	0.007
ANGLE FORMED BY LINE OF SIGHT AND VERTICAL PLANE	45	45
LIGHT SOURCE LUMINANCE	29106	29106
HEIGHT FROM OBSERVER'S EYE(H)	2	2
SOLID ANGLE	0.0017	0.0009
POSITION INDEX	7	7
Σ	29823	14912
UGR	21.9	19.5

Therefore, by forming the lens surface 50 on the cover 3, it is possible to reduce an apparent area of the LED 12, and reduce glare of LED light emitted from the straight-tube LED lamp 100 for an observer.
In the present example, the lens surface 50 is integrally molded with the cover 3 by extrusion molding; however, the lens surface 50 can be formed by pultrusion molding, and injection molding.
Or the lens surface 50 may be structured by adhering a concave lens (concave cylindrical lens) as a different member to the cover 3 (the same is applied to another example).
According to the embodiment of the present invention, it is possible to reduce glare by reducing a value of the UGR as a lamp itself, and therefore, it is possible to effectively use an existing device (light fixture) for a fluorescent lamp.
Additionally, it is possible to contribute to improvement of usability without any problems of adjusting a position of the light fixture.
A second example is illustrated in FIGs. 4 and 5.
The same parts as those in the first example are denoted by the same reference signs, and the above-described structural and functional explanations are omitted as long as they are unnecessary, and only main parts will be explained.
As illustrated in FIG. 4, in the present example, a plurality of lens surfaces 52 each having a small curvature radius are provided next to each other on an inner surface of the cover 3.
Each of the lens surfaces 52 has a concave cylindrical lens shape having power only in the lateral direction.
Each of the lens surfaces 52 is formed throughout in the longitudinal direction corresponding to the length of the LED substrate 11.
In other words, a number of lens surfaces 52 extending in the longitudinal direction are arranged next to each other on the inner surface of the cover 3.
FIG. 5 is an enlarged perspective diagram of the lens surfaces 52.
Also in the present example, by forming the lens surfaces 52 on the cover 3, it is possible to reduce an apparent area of the LED 12, and reduce glare of the LED light emitted from the straight-tube LED lamp 100.
Other structures of the straight-tube LED lamp 100 will be explained.
As described above, the power source substrate 7 is located on the inner side of the flat part 32 of the casing 2.
In a case where there is no electronic component on a surface opposite to the mounting surface on which the electronic components 9 are mounted of the power source substrate 7, and electrical insulation is ensured by applying an insulator such as a coating material and the like to the flat part 32, both (the power source substrate 7 and the flat surface 32) can be directly in contact with each other.
In the casing 2, a concave part 30 which is capable of accommodating the power source substrate 7 is formed.
The power source substrate 7 converts electrical current sent from a commercial power source from AC (Alternating Current) to DC (Direct Current), supplies the electrical current to the LED substrates 11a, 11b via the lead wires 13a, 13b, and lights the LEDs 12a, 12b.
As illustrated in FIG. 12, a position of a hole 24 provided at an end of the power source substrate 7 coincides with that of a hole 25 (see FIG. 13) provided in the flat part 32 of the casing 2, a clamp 15 is inserted into the coinciding holes 24 and 25, and the power source substrate 7 is fixed to the casing 2.
The clamp 15 is a locker which fixes an end in the longitudinal direction of the power source substrate 7 to the casing 2.
The clamp 15 has a head (elastically-deforming part) 15a which includes an upper head part 15b and a lower head part 15c, a stem 15d, and a base 15e.
A positional displacement in the longitudinal direction of the power source substrate 7 is thus regulated.
Although detailed illustration is not shown, another end of the power source substrate 7 is pressed by the lead wires 13a, 13b.
The hole 25 provided in the casing 2 is provided on the outside of the LED substrate 11b and at a position closer to the base 1b, in the longitudinal direction of the casing 2 (see FIG. 7).
That is, the clamp 15 is located on a side closer to the base 1b of the power source substrate 7 and is set to be on the outside of the LED substrate 11b.
By thus arranging the clamp 15 on the outside of the LED substrate 11b, an LED light flux does not become a shadow by interrupting.
In FIG. 11 and the like, in order to easily recognize the clamp 15, the clamp 15 is illustrated in a protruded manner.
In fact, as illustrated in FIG. 13, when the clamp 15 is inserted and pressed into the hole 25 of the flat part 32 from the outer side of the flat part 32, at the time of passing through the hole 24 of the power source substrate 7, the head (elastically-deforming part) 15a (upper head part 15b) of the clamp 15 spreads outward.
The power source substrate 7 is thus fixed to the casing 2 by a fingertip operation.
A heat radiation effect is improved by providing roughness to the outer surface of the casing 2, and additionally, the power source substrate 7 is set to be in close contact with the flat part 32 of the casing 2, and contact performance is increased by the clamp 15. And therefore, the heat from the power source substrate 7 is effectively radiated to the casing 2.
As illustrated in FIGs. 11 and 13, the length h1 (length from a position where the clamp 15 (upper head part 15b) makes contact with the power source substrate 7 to a position where the clamp 15 (base 15e) makes contact with the flat part 32 of the casing 2) and the length h2 (length of thickness of the flat part 32 of the casing 2 and thickness of the power source substrate 7) are made approximately equal, and therefore, it is possible to regulate a direction vertical to the power source substrate 7.
That is, it is possible to regulate movement of the power source substrate 7 in the direction of the thickness perpendicular to the longitudinal direction of the casing 2.
The concave part 30 is constituted of the flat part 32, and two ribs 31a, 31b as protrusions which stand out in the direction of the thickness of the power source substrate 7 from the flat part 32.
If the length L (see FIG. 8) in the longitudinal direction of the ribs 31 a, 31b is equal to the length of the casing 2, for example, extrusion processing can be performed.
That is, it is possible to integrally mold the ribs 31a, 31b with the casing 2 at the same time, and maintain a reduction in production cost.
Since the ribs 31a, 31b are formed on the flat part 32, an interval between protrusions is formed on a flat surface.
As illustrated in FIG. 11, when the width of the power source substrate 7, and an interval between the ribs 31a, 31b are D1 and D2, respectively, the relationship between D1 and D2 is set to establish D2>D1.
That is, the width of the concave part 30 is set such that the power source substrate 7 is inserted to the concave part 30.
The height H1 of the ribs 31a, 31b is set to be approximately equal to the height of the mounting surface of the power source substrate 7.
Thus, it is difficult for the power source substrate 7 to move in a right-and-left direction in the drawing, and therefore, it is difficult for the power source substrate 7 to deviate from the concave part 30.
Therefore, the ribs 31a, 31b prevent the power source substrate 7 from a positional displacement in a width direction (right-and-left direction) perpendicular to the longitudinal direction of the casing 2.
Accordingly, it is possible to inhibit disconnection (a sudden extinction of an LED lamp) of a lead wire caused by repetition of displacement in the width direction of the power source substrate 7 because of oscillation during commercial distribution, and shakes from an earthquake, or the like.
Additionally, also in a case of setting the power source substrate 7 in the casing 2 by sliding the power source substrate 7, it is possible to use the ribs 31a, 31b as guides, and therefore, it is easily possible to perform positioning, and insert the power source substrate 7.
The casing 2 is formed in a tubular shape having a uniform cross-sectional shape by extrusion molding, and pultrusion molding, and therefore, the power source substrate 7 may be inserted into the casing 2 from either end of the casing 2.
The height H1 of the ribs 31a, 31b is set to be a minimal height which is capable of preventing the positional displacement in the width direction of the power source substrate 7, and therefore, if the ribs 31a, 31b are provided throughout in the longitudinal direction of the casing 2, the mass does not largely increase.
Therefore, for example, even when the straight-tube LED lamp 100 is mounted on a ceiling, the mass of the casing 2 is increased, and the casing 2 is deformed by gravity, and yet there is no cause for concern of falling caused by shakes from an earthquake, and the like.
Conversely, rigidity in the longitudinal direction of the casing 2 is improved by a reinforcing effect of the ribs 31a, 31b, and therefore, it is possible to obtain a secondary effect of inflexibility.
As described above, by providing the ribs 31a, 31b by extrusion molding, and the like, most of the movement of the power source substrate 7 in the right-and-left direction is regulated.
FIG. 14 illustrates a modified example of the present embodiment.
In a case where necessary dielectric strength against leak voltage is not ensured between the casing 2 and the power source substrate 7, as illustrated in FIG. 14, a sheet-like insulator 41 that ensures dielectric strength between them is provided.
An inner width of the insulator 41 is set to be equal to or somewhat larger than the width E1 of the power source substrate 7.
An outer width E2 of the insulator 41 is set to be smaller than an interval E3 between the ribs 31a, 31b, and to be a width in which the insulator 41 can be inserted.
The insulator 41 has an edge part which stands out in the direction of the thickness of the power source substrate 7 at either end in the width direction.
The height H2 of the ribs 31a, 31b is set to be larger than the length of the thickness of the insulator 41 and the thickness of the power source substrate 7; however, if the height H2 is lower than the height K1 of the edge part of the insulator 41, the power source substrate 7 does not get over the ribs 31 a, 31b.
In a case of fixation using the clamp 15, the fixation is performed such that a hole is made in the insulator 41, the insulator 41 is sandwiched between the flat part 32 of the casing 2 and the power source substrate 7, and the clamp 15 is inserted into the hole.
The size of the hole (not-illustrated) of the insulator 41 is set such that the hole of the insulator 41 is encircled by the hole of the power source substrate 7 (The hole of the insulator 42 is smaller than the hole of the power source substrate 7.).
Note that fixation may be performed with a screw in place of the clamp 15.
Also in a case where the insulator 41 is inserted, if the length h3 (length of the thickness of the flat part 32 of the casing 2, the thickness of the insulator 41, and the thickness of the power source substrate 7) ≈ the length h1 (length from the position where the clamp 15 (upper head part 15b) makes contact with the power source substrate 7 to the position where the clamp 15 (base 15e) makes contact with the flat part 32 of the casing 2), it is possible to regulate movement of the power source substrate 7 in the direction of the thickness.
In the present example, since electrical current flowing to the power source substrate 7 does not flow to the casing 2 because of the existence of the insulator 41, there is no cause for concern of injury caused by electrical shock, or the like, fire, and the like.
In each example according to the embodiment of the present invention, the straight-tube LED lamp 100 is attachable to the light fixture 150 that enables the fluorescent lamp to light; however, needless to add, the straight-tube LED lamp 100 may be attachable to a light fixture exclusive for an LED.
According to the embodiment of the present invention, it is possible to reduce glare by reducing a value of the UGR as a lamp itself, and therefore, it is possible to effectively use an existing device (light fixture), and contribute to improvement of usability without any problems of position adjustment.
Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims.

Claims

A straight-tube LED lamp (100) comprising:
an elongated-shaped casing (2) which has two edges along a longitudinal direction;

a translucent cover member (3) which is attached to the casing so as to cover the edges of the casing throughout in the longitudinal direction; and

a plurality of semiconductor light-emitting devices (12a, 12b) which are arranged in the cover member along the longitudinal direction as a light source, wherein on an inner surface side of the cover member, the cover member has one or more lens surfaces (50, 52) which reduce an apparent area of the light source.
The straight-tube LED lamp (100) according to Claim 1, wherein the one or more lens surfaces (50, 52) include one or more concave cylindrical lens shapes having power in a lateral direction perpendicular to the longitudinal direction, respectively.
The straight-tube LED lamp (100) according to Claim 2, wherein when the cover member (3) includes the lens surface (50), the concave cylindrical lens shape is formed only in a center part of the cover member opposite to the light source in a cross-section in the lateral direction.
The straight-tube LED lamp (100) according to Claim 2, wherein when the cover member (3) includes the lens surfaces (52), the concave cylindrical lens shapes are formed next to each other along the longitudinal direction.
The straight-tube LED lamp (100) according to Claim 1, wherein the one or more lens surfaces (50, 52) are integrally molded with the cover member (3).
The straight-tube LED lamp (100) according to any one of Claims 2 to 4, wherein the one or more concave cylindrical lens shapes are integrally molded with the cover member (3).
A lighting device (200) comprising:
a straight-tube LED lamp (100) according to any one of Claims 1 to 6; and

a light fixture (150) to which the straight-tube LED lamp is attached.