JP2015038853A - Led bulb - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED bulb which can decorate a light emission part when the light emission part is constituted by arranging an LED chip three-dimensionally in a globe while imitating a filament bulb which is designed with a filament shape.SOLUTION: In an LED bulb 10, a band-shaped transparent flexible circuit board 12 is three-dimensionally arranged. Furthermore, an LED chip 17 which radiates light even to a connecting face side is mounted to the flexible circuit board 12. That is, since a light emission part composed of the LED chip 17 and the flexible circuit board 12 possesses a light emission characteristic similar to that of a filament, the LED bulb 10 can possess a decoration property similar to that of a filament bulb having a decoration property which is obtained by designing a filament shape.

Description

  The present invention relates to an LED bulb including an LED chip in a light emitting portion, and more particularly to an LED bulb capable of giving a decorative property to the light emitting portion.

  Lighting devices that use LED chips have become widespread. There are various types of lighting devices such as a bulb type, a straight tube type, a ceiling light, and an embedded type. In particular, a light bulb-type lighting device may have a dark impression due to the uneven light distribution due to the directivity of the LED chip. As one method for improving this light distribution, FIG. 1 of Patent Document 1 shows a method of three-dimensionally arranging LED chips in a globe. Therefore, FIG. 1 of Patent Document 1 is shown again in FIG. 5 and the structure thereof will be described.

  FIG. 5 is a perspective view of an LED bulb shown as a conventional example. In FIG. 5, the base 1 is connected to the upper part of the power storage unit 8, and the cover 2 (glove) is attached to the lower part. Inside the cover 2, a flexible circuit board 5 is fixed to the support bar 3 with a stopper 4. The flexible circuit board 5 is provided with a belt-like branch portion and has a cage shape as a whole. An LED chip 6 is mounted on each belt-like branch. In this LED bulb, each LED chip 6 is arranged substantially evenly on the surface of the cage-type flexible circuit board 5, so that when the LED chip 6 is turned on, a light emitting part composed of the flexible circuit board 5 and the LED chip 6 is formed. It becomes spherical and light is emitted from the cover 2 in all directions.

JP2003-59305A (FIG. 1)

  In a light bulb using a filament as a light source (hereinafter referred to as a filament light bulb), the shape of the filament may be designed to give the light emitting part a decorative property. Therefore, it has been demanded that the LED light bulb has a decorative property of the light emitting part by imitating the filament light bulb. However, in Patent Document 1, although some variations related to the shape of the flexible circuit board are described, it was originally intended to improve the light distribution characteristics (directivity), so there is no mention of technical aspects related to decorativeness. In other words, it has been difficult to express a decorative filament with the conventional configuration.

  Then, this invention is made | formed in view of the said subject, and when the LED chip is arrange | positioned three-dimensionally in a globe and a light emission part is comprised, the LED light bulb which can decorate the light emission part is provided. With the goal.

The LED bulb of the present invention is an LED bulb including an LED chip in a light emitting unit,
A flexible circuit board having a belt-like portion and a transparent substrate;
A plurality of LED chips containing LED dies,
The LED die has a pair of connection electrodes;
The LED chip is flip-chip mounted on the flexible circuit board, whereby the wiring electrode on the flexible circuit board and the connection electrode are directly connected.

  The flexible circuit board provided in the LED bulb of the present invention has a band shape as a whole or a part of the flexible circuit board. An LED chip is mounted on the belt-like portion. This LED chip incorporates an LED die provided with a pair of connection electrodes corresponding to an anode and a cathode. By flip-chip mounting the LED chip on the flexible circuit board, the connection electrode of the LED die is directly connected to the wiring electrode on the flexible circuit board. That is, there is nothing between the LED die and the flexible circuit board that blocks light emitted from the LED die toward the connection electrode.

  When the strip-shaped part of the flexible circuit board is three-dimensionally arranged in the globe and the LED chip is turned on, not only light is emitted to the upper surface (surface opposite to the mounting surface) and the side surface of the LED chip, Light emitted from the bottom surface (surface on the connection electrode side) of the LED chip passes through the transparent flexible circuit board, and is also emitted to the back side of the flexible circuit board (the side opposite to the mounting surface of the LED chip). In other words, the light emitting portion composed of the LED chip and the belt-like portion of the flexible circuit board emits light in all directions, and thus becomes similar to the light emission characteristics of the filament.

  A support column may be provided to stand inside, and one end of the flexible circuit board may be fixed to the support column.

  The support column is made of a conductor, has a substrate attachment portion at the tip, the one end of the flexible circuit board is fixed to the substrate attachment portion, and is electrically connected to the substrate attachment portion, and the current is supplied to the support column. May flow.

  The power supply board for supplying electric power to the flexible circuit board may be provided, and the other end of the flexible circuit board may be fixed to the power supply board via an elastic member.

  The elastic member may be electrically conductive, and power may be supplied from the power supply board to the flexible circuit board via the elastic member.

  The elastic member may be a spring.

  A transparent frame may be provided inside, and the flexible circuit board may be attached to the frame.

  The LED chip may include a plurality of types of LED chips, and each type of LED chip may constitute a series circuit.

  The number of the LED chip rows on the flexible circuit board may be smaller than the number of types of the LED chips.

  The plurality of types of LED chips have, in addition to the pair of connection electrodes, two short-circuit connection electrodes that are connected to each other, the pair of connection electrodes are arranged at one diagonal position, and the two Two short-circuit connection electrodes are arranged at the other diagonal position, and the LED chip array includes two types of LED chips, and one type of LED chip and the other type of LED chip each form a series circuit. May be.

  There are two LED chip arrays on the flexible circuit board, and the types of LED chips included in one LED chip array and the types of LED chip arrays included in the other LED chip are all or partly different. good.

  The LED chip includes four types of LED chip that emits red light, LED chip that emits green light, LED chip that emits blue light, and LED chip that emits white light. Two of them may be included, and the remaining two types may be included in the other LED chip row.

  The LED light bulb of the present invention emits light also to the back side of the flexible circuit board in the light emitting part composed of the LED chip and the belt-like part of the flexible circuit board, so that the light emitting part has a light emission characteristic similar to that of a filament. As described above, the LED bulb of the present invention has the same decorativeness as that of the filament bulb designed to have a decorative shape by designing the filament shape by designing the three-dimensional shape of the strip portion of the flexible circuit board.

The perspective view of the LED bulb shown as 1st Embodiment of this invention. The front view of the LED light bulb shown in FIG. Sectional drawing around the LED chip | tip of the LED bulb shown in FIG. The enlarged view around the flexible circuit board lower end part of the LED bulb shown in FIG. The perspective view of the conventional LED bulb. The perspective view of the LED chip contained in the LED bulb shown as 2nd Embodiment of this invention. FIG. 7 is an external view of the LED chip shown in FIG. 6. The top view of the flexible circuit board contained in the LED bulb shown as 2nd Embodiment of this invention. FIG. 9 is a perspective view of the flexible circuit board shown in FIG. 8. FIG. 9 is a schematic circuit diagram of the flexible circuit board shown in FIG. 8. The circuit diagram of the flexible circuit board shown in FIG. 8, and its peripheral part. The perspective view of the LED bulb shown as 3rd Embodiment of this invention. FIG. 13 is a perspective view in which a part of the frame 53 shown in FIG. 12 is cut out and enlarged. FIG. 13 is an exploded perspective view of the frame shown in FIG. 12.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4 and 6 to 14. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate.

(First embodiment)
First, the outline of the LED bulb 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of the LED bulb 10, and FIG. 2 is a front view of the LED bulb 10. In FIG. 2, the number of LED chips 17 mounted on the flexible circuit board 12 is reduced. The LED bulb 10 has a globe 11 at the top of a socket 14 and a base 15 at the bottom. Further, a support column 13 is attached to the center of the socket 14, and a cross-shaped substrate mounting portion 13 a is provided at the upper end of the support column 13. A power supply board 16 is mounted on the upper surface of the socket 14, and four strip-shaped flexible circuit boards 12 are attached between the board attachment portion 13 a and the power supply board 16 so as to draw a curve. A plurality of LED chips 17 are flip-chip mounted on the strip-shaped flexible circuit board 12.

The base material of the flexible circuit board 12 is made of transparent polyimide and has a thickness of 50 μm. A wiring electrode 36 (see FIG. 3) is formed on one surface of the flexible circuit board 12, and the wiring electrode and the connection electrode 34 (see FIG. 3) of the LED chip 17 are directly connected via solder. As will be described later, the LED chip 17 includes one LED die 35 (see FIG. 3), and the connection electrode 34 is a part of the LED die 35 and corresponds to the anode and the cathode. Each LED chip 17 is connected in series on the flexible circuit board 12. The support column 13 and the board mounting portion 13a are made of metal. The board mounting portion 13a fixes the upper end portion of the strip-shaped flexible circuit board 12 and is electrically connected to the series circuit of the LED chips 17 formed on the flexible circuit board 12. Connected to.

  A power supply circuit including a safety component such as a fuse (not shown), a current limiting resistor, and a bridge diode is mounted on the power supply board 16. This power supply circuit is connected to a commercial AC power supply via a base 15 and drives the LED chip 17 by full-wave rectification of the commercial power supply. The current flowing into the series circuit from the power supply board 16 at the lower end portion of the flexible circuit board 12 flows through the series circuit composed of the LED chips 17, and further flows into the board attachment portion 13 a from the upper end portion of the flexible circuit board 12. Return to the power supply board 16. Since the LED chip 17 is driven with a full-wave rectified waveform, the power supply circuit mounted on the power supply substrate 16 does not require a high withstand voltage and large capacity capacitor. As a result, the power supply circuit is reduced in size and can be stored in the small socket 14. When the commercial AC power supply is 100V and the threshold voltage of the LED chip 17 is 3V, the series circuit of the LED chips 17 included in the flexible circuit board 12 has about 30 stages.

  Next, the structure around the LED chip 17 will be described with reference to FIG. FIG. 3 is a cross-sectional view of one LED chip 17 and the flexible circuit board 12 in the vicinity thereof. As shown in FIG. 3, the LED chip 17 is flip-chip mounted on the wiring electrode 36 formed on the upper surface of the base material 37 of the flexible circuit board 12. The LED chip 17 is obtained by coating an LED die 35 with a fluorescent resin 31, and the LED die 35 includes a sapphire substrate 32, a semiconductor layer 33 formed thereunder, and a connection electrode 34.

  The sapphire substrate 32 has a thickness of about 150 μm. The semiconductor layer 33 includes an n-type GaN layer and a p-type GaN layer, and has a thickness of about 10 μm. The light emitting layer is a boundary between the n-type GaN layer and the p-type GaN layer. The connection electrodes 34 are an anode and a cathode, and are combined into two using an interlayer insulating film and multilayer wiring included in the semiconductor layer 33. Although the thickness of the connection electrode 34 can be set from several hundreds of nanometers to several tens of micrometers, in the LED chip 17, since the bottom surface of the chip is covered with the fluorescent resin 31, the thickness of the connection electrode 34 is set to several tens of micrometers. Yes.

  The fluorescent resin 31 that covers the LED die 35 is obtained by kneading and curing phosphor fine particles in a silicone resin. The LED die 35 has an upper thickness of 300 μm, a side thickness of 100 to 200 μm, and a bottom portion. The thickness is several tens of μm. For example, if the planar size of the LED die 35 is about 0.5 mm × 1.0 mm, the planar size of the LED chip 17 is about 0.8 mm × 1.3 mm. As described above, when the planar sizes of the LED die 35 and the LED chip 17 are substantially equal, the package may be referred to as a chip size package (also referred to as CSP).

  When a current is passed through the LED chip 17, the light emitting layer included in the semiconductor layer 33 emits light. Since this light emission is isotropic, it goes to the upper surface, side surface, and bottom surface side of the LED die 35. A part of the light is wavelength-converted by the fluorescent resin 31. At this time, since there is no submount substrate (also referred to as an interposer) or a light-shielding covering member between the LED die 35 and the flexible circuit board 12, the light traveling downward in the figure is a transparent portion of the flexible circuit board 12. , And is emitted from the back side of the flexible circuit board 12 (the lower side of the figure).

Next, the lower end portion of the flexible circuit board 12 will be described with reference to FIG. 4A and 4B are enlarged views of a lower end portion of the flexible circuit board 12 and a part of the power supply board 16, in which FIG. 4A is a perspective view and FIG. 4B is a front view. A spring 41 (elastic member) is attached to the lower end of the flexible circuit board 12. The upper part of the spring 41 is caulked to the flexible circuit board 12 using the attachment hole 42, and the lower part of the spring 41 is inserted into the through hole 43 of the power supply board 16 and fixed by the solder 44 on the lower surface of the power supply board 16. .

  The spring 41 not only holds and fixes the lower end of the flexible circuit board 12 but also forms a part of the current path in the same manner as the support 13 (see FIG. 1). That is, a current for turning on the LED chip 17 flows through the spring 41. As described above, the support column 13 and the board mounting portion 13a are electrically connected to the upper end of the strip-shaped flexible circuit board 12, so that the current generated from the power supply board 16 passes through the spring 41 and from the LED chip 17. It returns to the power supply board 16 via the series circuit and the support | pillar 13 which become.

  The flexible circuit board 12 of the present embodiment has a band shape as a whole, and is three-dimensionally arranged by the support columns 13. On the other hand, the LED light bulb of the present invention is not limited to a combination of a strip-shaped flexible circuit board and a support to configure the light emitting portion in three dimensions. For example, a plurality of strip-shaped portions may be provided on a single flexible circuit board, and the light source portion may be three-dimensional by bending the strip-shaped portions. At this time, the support can be omitted if the flexible circuit board has a core portion in addition to the plurality of belt-shaped portions. However, the consumption of the material for the flexible circuit board can be reduced by forming the entire flexible circuit board 12 in a strip shape as in this embodiment.

  Moreover, the support | pillar 13 of this embodiment consisted of the metal, and sent the electric current. On the other hand, the LED bulb of the present invention does not have to use a support as a current path. A more complicated light-emitting portion can be configured by using a support as an insulator and forming a circuit on the support.

  In addition, a conductive spring 41 is attached to the lower end portion of the flexible circuit board 12 of the present embodiment. On the other hand, the LED bulb of the present invention is not limited to a structure having a spring at the lower end. For example, the flexible circuit board may be directly fixed to the power supply board, or an elastic member such as rubber may be used instead of the spring. Further, the feeding path may be provided separately from the elastic member.

  Further, the bottom surface of the LED chip 17 of the present embodiment is covered with the fluorescent resin 31 (refer to FIG. 3 below). On the other hand, the bottom surface of the LED chip included in the LED bulb of the present invention does not necessarily have to be covered with the fluorescent resin. If the bottom surface is not covered with a fluorescent resin, the connection electrode 34 can be thinned. At this time, the wavelength-converted light emitted from the fluorescent resin 31 that covers the side surface of the LED die 35 has a component toward the lower side of the figure, so that the light emission and wavelength conversion of the LED die 35 are performed on the back side of the flexible circuit board 12. The mixed light is mixed.

(Second Embodiment)
In the LED light bulb 10 of the first embodiment, one type of LED chips 17 are arranged in a line in the band-shaped portion of the flexible circuit board 12 simulating a filament to constitute one series circuit. On the other hand, you may comprise a some series circuit in the strip | belt-shaped part of a flexible circuit board. At this time, if the light emission characteristics (types) of the LED chips included in each series circuit are made different, color adjustment can be performed by adjusting the current flowing through each series circuit.

For example, when two series circuits are provided, the emission color of the LED chip included in one series circuit is a warm color system (hereinafter abbreviated as w), and the emission color of the LED chip included in the other series circuit is a daylight color (hereinafter referred to as “winter color”). abbreviated as c). If it carries out like this, the luminescent color of a LED bulb can be adjusted from warm color to daylight color by the balance of light emission of one series circuit, and the other light emission. On the flexible circuit board, these two types of LED chips are alternately arranged in the order of w, c, w, c,... (One LED chip row), and also on the side of the LED chip mounting portion. If wiring is provided, two series circuits can be provided while arranging LED chips in a line. As a result, a toning function can be added while keeping the strip-like portion of the flexible circuit board thin and effectively imitating the filament.

  An LED chip that emits red light (hereinafter abbreviated as R), an LED chip that emits green light (hereinafter abbreviated as G), and an LED chip that emits blue light (hereinafter abbreviated as B) are prepared on the flexible circuit board. In addition, a series circuit composed of R, a series circuit composed of G, and a series circuit composed of B may be configured. In this case, an arbitrary emission color can be obtained by adjusting the emission ratio between the series circuits. Furthermore, on the flexible circuit board, these three types of LED chips are arranged in the order of R, G, B, B, G, R, R, G, B, B, G, R,. If wiring is also provided on the side of each part, three series circuits can be provided while arranging LED chips in a row. As a result, it is possible to add a toning function that emits light in an arbitrary color while keeping the belt-like portion thin and effectively imitating the filament.

  As an example of an LED bulb that can be toned while having a flexible circuit board imitating such a filament, an LED bulb 20 will be described as a second embodiment of the present invention with reference to FIGS. The LED bulb 20 is characterized by an LED chip 60 (see FIGS. 6 and 7) and a flexible circuit board 85 (see FIG. 8) on which the LED chip 60 is mounted. For this reason, the overall view of the LED bulb 20 is not shown in the description of the second embodiment, but is similar to the LED bulb 10 shown in FIG.

  First, the outer shape of the LED chip 60 included in the LED bulb 20 (reference numeral is not shown) will be described with reference to FIG. FIG. 6 is a perspective view of the LED chip 60. The LED chip 60 is a rectangular parallelepiped, and the coating resin 61 is observed. As will be described later, the LED chip 60 includes four types of LED chips that emit red light, LED chips that emit green light, LED chips that emit blue light, and LED chips that emit white light. Since the outer shape is the same except for the component 61, the description will be made without distinguishing the difference in the emission color (type) (the same applies to FIG. 7).

  Next, the outer shape of the LED chip 60 included in the LED bulb 20 (reference numerals are not shown) will be described in more detail with reference to FIG. 7A and 7B are external views of the LED chip 60, where FIG. 7A is a plan view, FIG. 7B is a front view, and FIG. 7C is a bottom view. When the LED chip 60 is viewed from above, the coating resin 61 is observed. When the LED chip 60 is viewed from the front, the connection electrodes 71 and 73 are observed on the coating resin and the lower part thereof. In FIG. 5B, an LED die 75 is shown to show the state in the coating resin. The LED die 75 includes a sapphire substrate 75a, a semiconductor layer 75b, and connection electrodes 71, 72, 73, and 74.

  When the LED chip 60 is viewed from the bottom side, the coating resin 61 and the connection electrodes 71, 72, 73, and 74 surrounded by the coating resin 61 are observed. The connection electrodes 71 and 72 are an anode and a cathode, respectively, and the connection electrodes 73 and 74 are short-circuit connection electrodes. The pair of connection electrodes 71 and 72 for the anode and cathode are arranged at diagonal positions, and similarly, the two short-circuit connection electrodes 73 and 74 are also arranged at diagonal positions. The positions of the anode and cathode connection electrodes 71 and 72 are adjusted by multilayer wiring in the semiconductor layer 75 b included in the LED die 75. Similarly, the short-circuit connection electrodes 73 and 74 are connected by a multilayer wiring in the semiconductor layer 75 b included in the LED die 75. For the sake of explanation, the semiconductor layer 75b is seen through.

Next, the flexible circuit board 85 on which the LED chips 81, 82, 83, and 84 are mounted will be described with reference to FIG. FIG. 8 is a plan view of a flexible circuit board 85 included in the LED bulb 20 (reference numerals are not shown). Four types are mounted: an LED chip 81 that emits red light, an LED chip 82 that emits green light, an LED chip 83 that emits blue light, and an LED chip 84 that emits white light. In the left LED chip row in the figure, LED chip 8
1 and LED chips 82 are alternately arranged, and in the right LED chip row, LED chips 84 and 83 are alternately arranged. A wiring electrode 86 is observed between the LED chips 81 and 82, and similarly, the wiring electrode 86 is also observed between the LED chips 84 and 83.

  In the LED chip 81, phosphor fine particles for converting the wavelength of blue light emitted from the LED die 75 (see FIG. 7) into red are mixed in the coating resin 61 (see FIG. 7). Similarly, in the LED chip 82, phosphor fine particles that are converted into green wavelength are mixed in the coating resin 61. In the LED chip 83 that emits blue light, the coating resin 61 is transparent. In the LED chip 84, phosphor fine particles that are converted into yellow are mixed in the coating resin 61, and light is emitted in white by a mixed color of blue light emission and yellow light emission. The transparent resin that is the base of the coating resin 61 is silicone.

  Next, the connection state of the LED chips 81 to 84 will be described with reference to FIG. FIG. 9 is a perspective view of the flexible circuit board 85 shown in FIG. In FIG. 9, the connection electrode 71 in the upper right corner of each LED chip 81 to 84 is an anode, the connection electrode 72 in the lower left corner is a cathode, and the connection electrode 73 in the upper left corner and the connection electrode 74 in the lower right corner are short-circuit connections. Electrode. The anode connection electrode 71 of the LED chip 81 is connected to the short-circuit connection electrode 74 of the upper LED chip 82 in the figure, and the cathode connection electrode 72 of the LED chip 81 is the short-circuit connection electrode of the lower LED chip 82 in the figure. 73 is connected. Similarly, the anode connection electrode 71 of the LED chips 82, 83, 84 is connected to the short-circuit connection electrode 74 of the upper LED chip 81, 84, 83 in the drawing, and the cathode connection electrode 72 of the LED chips 82, 83, 84. Is connected to the short-circuit connection electrode 73 of the lower LED chip 81, 84, 83 in the drawing.

  Next, the connection state of the LED chips 81 to 84 will be described in more detail with reference to FIG. FIG. 10 is a schematic circuit diagram of the flexible circuit board 85 shown in FIG. 8, which shows four LED chips 81a, 81b, 82a, and 82b in the left LED chip row of FIG. In the figure, suffixes are added to the reference numerals to indicate LED chips individually.

  In FIG. 10, the cathode (connection electrode 72) of the LED included in the LED chip 81a is connected to the anode (connection electrode 71) included in the LED chip 81b via the short-circuit connection electrodes 73 and 74 of the LED chip 82a. ing. That is, the LED included in the LED chip 81a and the LED included in the LED chip 81b are connected in series. Similarly, the LEDs included in the LED chip 82a and the LEDs included in the LED chip 82b are connected in series. That is, when the path between the short-circuit connection electrodes 73 and 74 is regarded as a simple wiring, in the LED chip row on the left side of FIG. 8, the LED chips 81 constitute a series circuit and the LED chips 82 constitute a series circuit. To do. Similarly, in the LED chip row on the right side of FIG. 8, the LED chips 83 also form a series circuit, and the LED chips 84 also form a series circuit.

  Finally, the entire circuit of the LED bulb 20 will be described with reference to FIG. FIG. 11 is a circuit diagram of the flexible circuit board 85 (see FIG. 8) and its peripheral portion shown in FIG. On the flexible circuit board 85, there are a series circuit 101 composed of LED chips 81, a series circuit 102 composed of LED chips 82, a series circuit 103 composed of LED chips 83, and a series circuit 104 composed of LED chips 84. The upper ends of the series circuits 101 to 104 are connected to the power source 105 on the high voltage side. Current limiting circuits 101a, 102a, 103a, 104a are connected to the lower ends of the series circuits 101, 102, 103, 104, respectively. The other ends of the current limiting circuits 101a, 102a, 103a, 104a are connected to the power source 106 on the low voltage side, and are controlled independently by the control circuit 107.

Since the light emission amounts of the series circuits 101 to 104 can be independently adjusted as described above, an arbitrary light emission color can be obtained. At this time, the power source 105 may be supplied from the support 13 (see FIG. 1). The lower end portion of the flexible circuit board 85 and the power supply board 16 (see FIG. 1) are connected by a connector. The lower end portion of the flexible circuit board 85 and the power supply board 16 may be connected and fixed by an elastic member such as a spring as in the LED bulb 10 of the first embodiment. The circuit diagram of FIG. 11 is drawn with respect to one strip-shaped flexible circuit board, but the LED bulb 20 is provided with a plurality of flexible circuit boards in the same manner as the LED bulb 10 (see FIG. 1). At this time, the control circuit 107, the current limiting circuits 101a to 104a, and the like are preferably integrated, and the toning control is performed by a control signal superimposed on a wireless or commercial power source.

  Further, in the LED bulb 20, the flexible circuit board 85 has only two LED chip rows, the wiring electrodes 86 are only provided in the adjacent portions of the LED chips 81 to 84, and the wiring (wiring) is provided on the side portion. Since there is no electrode), the band-shaped part is made thinner accordingly.

  The LED chips 81 to 84 have four types of emission colors of red, green, blue, and white, and one of these LED chip rows (left side in FIG. 8) has two types (LEDs that emit light in red and green). Chips 81 and 82), and the remaining two types (LED chips 83 and 84 emitting light in blue and white) were included in the other LED chip row (right side in FIG. 8). However, the combination of the light emission colors is not limited to this, and the type of the LED chip included in one LED chip row may be different from the type of the LED chip included in the other LED chip row. For example, the LED chip 84 emits green light. This makes it feel bright because of its high visibility to green. Further, the combination of the emission colors may be red, green, blue, or orange. This approaches the spectrum of blackbody radiation. The LED die 75 may emit near ultraviolet light. In this way, the spectrum of black body radiation can be made closer.

(Third embodiment)
In the LED bulb 10 shown in FIGS. 1 and 2, one end of a flexible circuit board 12 on which a large number of LED chips 17 are mounted is fixed to a support column 13 provided in the globe 11. That is, the flexible circuit board 12 is arranged in a semi-fixed state in the globe 11. For this reason, the back surface of the flexible circuit board 11 comes into contact with air. However, since air has poor thermal conductivity, the LED bulb 10 cannot efficiently dissipate the heat generated by the LED chip 12 when the current is increased in order to increase the light emission luminance of the LED chip 12. As a result, the luminous efficiency of the LED bulb 10 decreases. Further, since the flexible circuit board 12 is in a semi-fixed state, there is a problem that the flexible circuit board 12 is cut due to vibration or the like, or the assemblability is lowered.

  Accordingly, as a third embodiment, an LED bulb 50 with improved heat dissipation, mechanical strength, and assemblability while maintaining the same decorativeness as that of a filament bulb will be described with reference to FIGS.

  First, the external appearance of the LED bulb 50 will be described with reference to FIG. FIG. 12 is a perspective view of the LED bulb 50. The LED bulb 50 includes a globe 51, a socket 54, and a base 55, and a frame 53 is disposed inside the globe 51. The base 53c (see FIG. 14) of the frame 53 is inserted into the socket 54. Further, the frame 53 has a structure in which a branch-like portion that spreads out into four forks (cross shape) at the top is united again at the base 53. Further, a strip-shaped flexible circuit board 52 (see FIG. 13) on which the LED chip 57 is mounted is attached to the outside of the branch-shaped portion of the frame 53. The frame 53 is made of transparent plastic, and allows light emitted from the mounting surface side of the LED chip 57 to pass therethrough.

Next, the frame 53 provided in the LED bulb 50 will be described in more detail with reference to FIG. FIG. 13 is a perspective view in which a part of the frame 53 of the LED bulb 50 is cut out and enlarged. In the upper part of FIG. 13, a cross section 53d of the frame 53 and a cross section 52d of the flexible circuit board 52 are observed, and the cross section 53d of the frame 53 has an H shape. Outside of frame 53 (glove 51
Side, see FIG. 12), a flexible circuit board 52 is attached so as to be fitted. Further, an LED chip 57 is flip-chip mounted on the flexible circuit board 52.

  The flexible circuit board 52 is made of transparent polyimide, similar to the flexible circuit board 12 built in the LED bulb 10 shown in FIG. The LED chip 57 is the same as the LED chip 12 mounted on the flexible circuit board 12 of the LED bulb 10. Here, a brown and translucent polyimide substrate may be adopted as the flexible substrate 52. In this case, since the phosphor on the mounting surface side of the LED chip 57 is thin (see FIG. 3), the light emission is bluish. However, the brown polyimide substrate absorbs the blue component, so that it is emitted toward the outside of the globe 51. The color tone of light and the color tone of light emitted toward the inside of the globe 51 are balanced.

  Finally, the structure related to the assembly of the frame 53 will be described with reference to FIG. FIG. 14 is an exploded perspective view of the frame 53 included in the LED bulb 50. The frame 53 includes an upper portion 53a, a lower portion 53b, and a base portion 53c. The upper part 53a and the lower part 54 of the frame 53 are separated, and the lower part 53b and the base part 53c of the frame 53 are integrated. The upper part 53a and the lower part 53b of the frame 53 are provided with a convex part and a concave part (not shown) at their respective connecting parts, and are fixed by an adhesive in a state in which these are fitted. The reason why the upper part 53a and the lower part 53b of the frame 53 are separated is that the frame 53 must be made of a mold in consideration of mass productivity, and the frame 53 is divided into two parts so that it can be removed from the mold.

  As described above, since the frame 53 is transparent, light emission on the mounting surface side of the LED chip 57 passes through the flexible circuit board 52 and the frame 53 and is emitted toward the center of the LED bulb 50. As a result, the LED bulb 50 can maintain a decorative property equivalent to that of the filament bulb. Further, when the non-mounting surface side of the flexible circuit board 52 comes into contact with air through the frame, the surface area in contact with the air increases, so that the heat dissipation is improved. Further, since the flexible circuit board 52 is fixed to the rigid frame 53, the mechanical strength of the flexible circuit board 52 is increased, and the flexible circuit board 52 is prevented from being cut even if the LED bulb 50 vibrates. . Further, since the flexible circuit board 52 is fixed to the frame 53, the flexible board 52 is not deformed when the flexible circuit board 53 is placed in the globe 51, so that the assemblability is improved.

  In the LED bulb 50 of this embodiment, the frame 53 includes four branch portions. However, the LED light bulb of the present invention including the frame is not limited to the one in which the frame includes four branch portions. For example, a structure in which a frame crosses flat plates may be taken. At this time, the flexible circuit board is attached to the side surface of the flat plate. In addition, as in the LED bulb 20 shown in the second embodiment, the LED bulb 50 also includes a plurality of types of LED chips 57 mounted on the flexible circuit board 52, or the LED chips 57 are arranged in two rows on the flexible circuit board 52. You may do it.

10, 20, 50 ... LED bulbs,
11, 51 ... Globe,
12, 52, 85 ... flexible circuit board,
13 ... posts
13a ... board mounting part,
14, 54 ... socket,
15, 55 ...
16 ... power supply board,
17, 57, 60, 81, 82, 83, 84 ... LED chip,
31 ... Fluorescent resin,
32, 75a ... sapphire substrate,
33, 75b ... semiconductor layer,
34, 71, 72, 73, 74 ... connection electrodes,
35,75 ... LED die,
36, 86 ... wiring electrodes,
37. Base material,
41 ... Spring (elastic member),
42 ... mounting hole,
43 ... through hole,
52d: cross section of flexible circuit board,
53 ... Frame,
53a ... upper part of the frame,
53b ... the lower part of the frame,
53c ... base of the frame,
53d: Cross section of frame,
61 ... Coating resin,
101, 102, 103, 104 ... series circuit,
101a, 102a, 103a, 104a ... current limiting circuit,
105, 106 ... power supply,
107: Control circuit.

Claims (12)

In an LED bulb equipped with an LED chip in the light emitting part
A flexible circuit board having a belt-like portion and a transparent substrate;
A plurality of LED chips containing LED dies,
The LED die has a pair of connection electrodes;
An LED bulb characterized in that the wiring electrode and the connection electrode on the flexible circuit board are directly connected by flip-chip mounting the LED chip on the flexible circuit board.   The LED light bulb according to claim 1, further comprising: a support column that stands inside, wherein one end of the flexible circuit board is fixed to the support column.   The support column is made of a conductor, has a substrate attachment portion at the tip, the one end of the flexible circuit board is fixed to the substrate attachment portion, and is electrically connected to the substrate attachment portion, and the current is supplied to the support column. The LED bulb according to claim 2, wherein   The power supply board for supplying electric power to the flexible circuit board is provided, and the other end of the flexible circuit board is fixed to the power supply board via an elastic member. LED bulb.   The LED bulb according to claim 4, wherein the elastic member has conductivity, and power is supplied from the power supply board to the flexible circuit board through the elastic member.   The LED light bulb according to claim 4, wherein the elastic member is a spring.   The LED bulb according to claim 1, further comprising a transparent frame inside, wherein the flexible circuit board is attached to the frame.   The LED bulb according to any one of claims 1 to 7, wherein the LED chip includes a plurality of types of LED chips, and each type of LED chip constitutes a series circuit.   The LED bulb according to claim 8, wherein the number of the LED chip rows on the flexible circuit board is smaller than the number of types of the LED chips.   The plurality of types of LED chips have, in addition to the pair of connection electrodes, two short-circuit connection electrodes that are connected to each other, the pair of connection electrodes are arranged at one diagonal position, and the two The short-circuit connection electrodes are arranged at the other diagonal position, and the LED chip row includes two kinds of LED chips, and one kind of LED chip and the other kind of LED chip respectively constitute a series circuit. The LED bulb according to claim 9.   There are two LED chip rows on the flexible circuit board, and the types of LED chips contained in one LED chip row and the types of LED chip rows contained in the other LED chip are all or partly different. The LED bulb according to any one of claims 8 to 10, wherein The LED chip includes four types of LED chip that emits red light, LED chip that emits green light, LED chip that emits blue light, and LED chip that emits white light. Two of them are included, and the remaining two in the other LED chip row
The LED bulb according to claim 11, wherein types are included.

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