JP2002314136A - Semiconductor light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actuate a semiconductor light emitting device, without using any special booster circuit, etc. SOLUTION: The semiconductor light emitting device comprises a tubular fluorescent member (1), a semiconductor light emitting element (3) disposed in the member (1) and a plurality of outer leads (4, 5) which are fixed to both ends of the member (1) and electrically connected to the light emitting element (3). The outer leads (4, 5) comprise leading parts (4a, 5a) extending out of the member (1) and terminals (4b, 5b) which are disposed in the member (1) and electrically connected to the element (3). The member (1) has a light transmission to a light emitted from the element (3) and comprises a fluorescent substance for absorbing the light emitted from the element (3) to convert to other light emitting wavelengths. This actuates the light emitting element (3) to light at a low voltage, without needing a booster circuit generating high frequency noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor light emitting device,
In particular, the present invention relates to a semiconductor light emitting device that converts the wavelength of light emitted from a semiconductor light emitting element disposed in a fluorescent member and emits the light to the outside.

[0002]

2. Description of the Related Art As shown in FIG. 28, a phosphor layer (12) containing a fluorescent substance is applied on the inner surface of a glass tube (11) constituting a conventional cold cathode fluorescent tube, and a tubular glass tube (11) is formed. The inside of) is evacuated and a small amount of mercury and an inert gas such as argon or neon are injected, and both ends of the glass tube (11) are sealed. A pair of external leads (4, 5) provided at one end and the other end of the glass tube (11) are a pair of discharge electrodes inside the glass tube (11).
(51, 52).

When a voltage is applied between a pair of external leads (4, 5), a discharge occurs between the discharge electrodes (51, 52), and the mercury is excited by receiving electric energy to generate ultraviolet rays, and a glass tube is produced.
When ultraviolet light is applied to the phosphor layer (12) on the inner surface of (11), the phosphor layer (12) excited by ultraviolet light emits visible light having a wavelength determined by the type of the phosphor (2), Visible light is emitted outside through the glass tube (11). When three kinds of phosphors (2) emitting three primary colors of red light, green light and blue light are mixed in an appropriate ratio and used for the phosphor layer (12), the emission of the three kinds of phosphors (2) is mixed. In addition, a three-wavelength cold cathode fluorescent tube can be formed by emitting white light having three primary color components from the cold cathode fluorescent tube. A three-wavelength cold cathode fluorescent tube is frequently used in a notebook computer or the like as a white backlight light source of a transmission type color liquid crystal display device.

[0004]

The conventional cold cathode fluorescent lamps have various problems. First, a special boosting circuit such as a boosting inverter that generates a dischargeable high voltage is required. Secondly, high frequency noise generated by the switching operation of the inverter easily induces a microcomputer or the like built in a device incorporating the cold cathode fluorescent tube to malfunction. Third, because the amount of heat generated is relatively large,
It is necessary to improve the heat dissipation function. Fourth, the lighting conditions are affected by the ambient temperature, and it takes a long time to reach a stable operation region in a low-temperature environment. Fifth, when the fluorescent tube is reduced in diameter to make it smaller, discharge becomes difficult. Sixth, discarding mercury, which is a harmful substance filled in the discharge tube, causes environmental pollution.

An object of the present invention is to provide a semiconductor light emitting device which does not require a special booster circuit or the like. An object of the present invention is to provide a semiconductor light emitting device that does not generate high frequency noise. An object of the present invention is to provide a semiconductor light emitting device that generates less heat. An object of the present invention is to provide a semiconductor light emitting device in which lighting conditions are not affected by environmental conditions used. An object of the present invention is to provide a semiconductor light emitting device that can be reduced in diameter. The present invention
It is an object of the present invention to provide an elongated semiconductor light emitting device that does not use mercury that generates environmental pollution. That is, an object of the present invention is to provide an alternative light emitting device which does not have various disadvantages generated in a cold cathode fluorescent tube.

[0006]

A semiconductor light emitting device according to the present invention comprises a tubular fluorescent member (1), a semiconductor light emitting element (3) disposed in the fluorescent member (1), and a fluorescent member (1). A plurality of external leads (4, 5) fixed to both ends and electrically connected to the semiconductor light emitting element (3) are provided. Each of the external leads (4, 5) has a lead portion (4a, 5a) extending outside the fluorescent member (1).
And a semiconductor light emitting element disposed inside the fluorescent member (1)
And (3) a terminal portion (4b, 5b) electrically connected to (3). The fluorescent member (1) has a light transmitting property with respect to light emitted from the semiconductor light emitting element (3), and absorbs light emitted from the semiconductor light emitting element (3) and converts the light to another emission wavelength. It has a fluorescent material. Unlike conventional cold-cathode fluorescent tubes, a booster circuit that generates high-frequency noise is not required, and the semiconductor light-emitting element (3) can be turned on at a low voltage.

In an embodiment of the present invention, a semiconductor light emitting device
(3) is a gallium nitride-based LED chip having a light-emitting layer made of a gallium nitride-based compound semiconductor and having an emission wavelength peak of 420 nm to 490 nm. The fluorescent substance is, for example,
Formula _{(Y 1-x, Gd x} ) 3 (Al 1-y, Ga y) 5 O
₁₂ : Ce _z (however, 0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5, 0.001
≦ z ≦ 0.5). 420nm emission wavelength peak
If a blue LED chip of ４490 nm is used as the semiconductor light emitting device (3) and combined with the YAG: Ce based phosphor (2), the blue light of the semiconductor light emitting device (3) and the YAG: Ce based phosphor (2) The light emitted from the semiconductor light emitting device is mixed with the yellow light having a wide spectrum, which is a light emission of the semiconductor light emitting device, so that white light having a wide spectrum can be obtained.

The semiconductor light-emitting device (3) has a light-emitting layer made of a gallium nitride-based compound semiconductor, has a light-emitting layer made of a gallium nitride-based compound semiconductor having a peak emission wavelength of 365 to 420 nm, and has a light-emitting wavelength peak. Is 365 nm
A 420 nm gallium nitride LED chip, wherein the fluorescent materials are a blue fluorescent material having an emission peak at 420 nm to 490 nm, a green fluorescent material having an emission peak at 520 nm to 570 nm, and a red fluorescent material having an emission peak at 590 nm to 700 nm. An interference filter (13) made of a material and reflecting light of a wavelength emitted from the semiconductor light emitting element (3) and transmitting light of a wavelength emitted from the phosphor is provided on the outer surface or inner surface of the fluorescent member (1). If the formed semiconductor light emitting device is used, it is possible to emit white light due to color mixture having three primary color components of blue, green, and red light of the phosphor to the outside of the semiconductor light emitting device.

The fluorescent member (1) includes a first light-transmitting member (11) formed in a tubular shape, and a phosphor layer (10) on which an inner surface of the first light-transmitting member (11) is coated with a fluorescent substance. 12). Instead of separately forming the phosphor layer (12), a first light-transmissive member (11) containing a fluorescent substance therein and formed in a tubular shape may be used.

A first light-transmitting member (11) formed in a tubular shape
When the fluorescent member (1) is constituted by the first light transmitting member (11) and the second light transmitting member (14) filled in the first light transmitting member (11), the first light transmitting member (11) Can be coated or contained with a fluorescent substance. A first light-transmissive member (11) formed in a tubular shape from light-transmitting glass or resin; and a resin filled in the first light-transmitting member (11) and having light-transmitting property. A fluorescent member with the second translucent member (14)
The constitution (1) may be adopted, and a fluorescent substance may be blended in the second translucent member (14).

An interference filter (13) that reflects light of the wavelength emitted from the semiconductor light emitting element (3) and transmits light of the wavelength emitted from the fluorescent substance is formed on the outer surface or the inner surface of the tubular fluorescent member (1). May be. Peak emission wavelength is 365nm ~ 4
When a 20 nm near-ultraviolet LED chip is used as the semiconductor light emitting element (3) and the fluorescent substance is a mixed phosphor of blue, green and red, the light of the wavelength emitted from the semiconductor light emitting element (3) is reflected and the fluorescent substance is used. If an interference filter (13) that transmits light of a wavelength emitted from the fluorescent member (1) is formed on the outer surface or the inner surface of the fluorescent member (1), the near-ultraviolet of the LED chip that passes through the particle gap of the phosphor (2) and is not converted in wavelength While the light is reflected and returned to the fluorescent material side to be wavelength-converted again, the visible light whose wavelength has been converted by the fluorescent material is emitted to the outside, so that leakage of near-ultraviolet light to the outside is prevented, and visible light The output can be increased.

Further, a light reflecting portion may be formed on a part of the outer surface of the fluorescent member (1). For example, if the fluorescent member (1) has a cylindrical shape and only one half (one outer surface) of the outer surface is provided with a metal-deposited film of aluminum or the like, light generated in the fluorescent member (1) is reflected on one outer surface. And concentrate on the other exterior,
Light extracted from the other outer surface of the fluorescent member (1) can be increased.

An automatic dimming circuit that detects light from the semiconductor light emitting element (3) and surrounding external light, adjusts the amount of light emitted from the semiconductor light emitting element (3) in accordance with increase or decrease in external light, and always maintains a constant brightness.
(33) or an overheat protection circuit (32) that automatically shuts off the lighting current of the semiconductor light emitting element (3) when the temperature of the semiconductor light emitting element (3) reaches a preset limit value. Good. The semiconductor light emitting element (3) provided inside the fluorescent member (1) may be single or plural. Further, the semiconductor light emitting element (3) may be arranged along the inner surface of the first light transmitting member, and the fluorescent member
(1) may be arranged in the length direction between one end and the other end.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a semiconductor light emitting device according to the present invention will be described below with reference to FIGS.

1 to 3 show a first embodiment of a tubular semiconductor light emitting device according to the present invention. This semiconductor light emitting device includes a tubular fluorescent member (1), a wiring board (2) disposed inside the fluorescent member (1), and an adhesive (not shown) at a predetermined position on the wiring board (2). Multiple semiconductor light-emitting devices fixed by
(3) and a pair of external leads (4, 5) fixed to each end of the fluorescent member (1) and electrically connected to the semiconductor light emitting element (3)
And

[0016] Length 58.0mm, width 0.4mm, thickness 0.2mm
The wiring board (2) having the following external dimensions is formed of a resin plate of paper phenol, paper epoxy, glass epoxy, polyimide, or the like, or a ceramic plate of alumina, forsterite, or the like. The conductor pattern (7) on the wiring board (2) is connected to the terminal portion (4) by an adhesive means such as a conductive adhesive, soldering, welding or the like.
b, 5b).

A sealing plug (6) is fixed to each end of the fluorescent member (1), and an external lead (4, 5) is provided with a through hole (6a) provided substantially at the center of the sealing plug (6). Fixed or buried inside. External lead
(4, 5) forms a lead portion (4a, 5a) protruding from the sealing plug (6) and a terminal portion (4b, 5b) arranged inside the fluorescent member (1). The lead portions (4a, 5a) are connected to an external conductor (not shown) for supplying power, and the terminal portions (4b, 5b) are conductor patterns (7) arranged on the wiring board (2) in the fluorescent member (1). Is electrically connected to The conductor pattern (7) is connected to the electrodes of the adjacent semiconductor light emitting elements (3) via bonding wires (8), and the electrodes of each semiconductor light emitting element (3) are electrically connected via bonding wires (9) sequentially. Are serially connected to each other.

The semiconductor light-emitting element (3) is a gallium nitride-based blue LED chip having a light-emitting layer made of a gallium nitride-based compound semiconductor and having an emission wavelength peak of 420 nm to 490 nm. The blue LED chip fixed at a predetermined position on the wiring board (2) with an adhesive (not shown) has a width of 0.34 m.
It has an outer dimension of 0.1 m and a height of 0.1 mm, and is used in a number to obtain a required brightness, for example, 5 to 7 pieces.

The fluorescent member (1) has a length of 60 mm and an outer diameter of 1.8 m.
It comprises a light-transmitting cylindrical glass tube (11) formed of silica glass having an inner diameter of 1.4 mm and a phosphor layer (12) formed on the inner surface of the glass tube (11). Semiconductor light emitting device
Phosphor layer (12) that has light transmissivity to light emitted from (3) and absorbs light emitted from semiconductor light emitting element (3) and converts it to another emission wavelength, for example, Chemical formula (Y
_{1-x, Gd x) 3} (Al 1- y, Ga y) 5 O 12: C
e _z (where, 0 ≦ x ≦ 0.5,0 ≦ y ≦ 0.5,0.001 ≦ z ≦ 0.
The fluorescent material includes a YAG: Ce-based fluorescent material represented by 5). The phosphor layer (12) is formed by coating a coating member made of a liquid resin or a metal alkoxide-based coating agent with YA.
G: Mix Ce-based fluorescent powder, apply to the inner surface of glass tube (11) cut to a predetermined length by suction, spraying, etc. to a thickness of about 0.1 to 0.2 mm, and then dry. It is formed by heat curing.

When assembling the semiconductor light emitting device, after fixing the semiconductor light emitting element (3) to the wiring board (2), the gap between each electrode of the semiconductor light emitting element (3) and the conductor pattern (7) is about 0.15 mm. Connect with bonding wires (8, 9) at the loop height of
External leads (4, 5) are connected to the conductor pattern (7) to form a wiring board assembly. To protect the semiconductor light emitting element (3) and bonding wires (8, 9) and improve light extraction efficiency,
The surface of the semiconductor light emitting device (3) and the bonding wires (8,
9) Put a protective member (not shown) such as silicone resin on 0.2m
It may be applied with a coating thickness of about m.

Subsequently, the wiring board assembly having the adhesive (not shown) applied to the back surface of the wiring board (2) is inserted into the glass tube (11) and fixed to the glass tube (11). The thickness of the wiring board (2) is 0.2 mm, the height of the blue semiconductor light emitting element (3) is 0.1 mm, the loop height of the bonding wires (8, 9) is 0.15 mm, and the thickness of the coating of the protective member. Is 0.2 mm, and the distance from the lower surface of the wiring board (2) to the upper surface of the protective member is 0.4 mm. Therefore, even if the thickness of the phosphor film (12) is considered, the size is sufficiently large. The wiring board assembly can be inserted with a margin into the cylindrical glass tube (11) having an inner diameter of 1.4 mm. Glass tube (11)
And a sealing plug made of ceramic or resin using an adhesive (not shown) to connect one end and the other end of the wiring board (2).
Secure with (6).

Part of the light emitted from the semiconductor light emitting device (3) excites the fluorescent substance in the phosphor layer (12), and the phosphor layer (1) is excited.
2) produces yellow light with a broad spectrum. Therefore,
Light in which blue light of the semiconductor light emitting element (3) and yellow light of the phosphor layer (12) are mixed is emitted from the semiconductor light emitting device to the outside. In this case, if the mixing ratio of the fluorescent substance to the coating member constituting the phosphor layer (12) and the coating thickness of the coating member to the inner surface of the glass tube (11) are appropriately controlled, the white color having a broad spectrum shown in FIG. Light is obtained. In this embodiment, since the tube light emitting device has a very compact shape and a high brightness with a tube length of 60 mm and a tube diameter of 1.8 mm, the liquid crystal display device of a small mobile device such as a PDA (next generation information device). Can be suitably used.

FIGS. 4 to 4 show a tubular semiconductor light emitting device according to the present invention.
In the second embodiment shown in FIG. 6, the fluorescent member (1) is made of a light-transmitting cylindrical acrylic resin tube (11a) in which a fluorescent substance powder is compounded, and the fluorescent member (1) is of the first embodiment. The same semiconductor light emitting device (3) and fluorescent substance as in the embodiment are used. A fluorescent substance powder is mixed with an acrylic resin material, injection molding method,
After being formed into a tube by a casting method or the like, it is cut into a predetermined length to produce the fluorescent member (1). In the second embodiment, the same operation and effect as those of the first embodiment can be obtained, but the mixing ratio of the fluorescent substance mixed with the acrylic resin material,
By appropriately controlling the thickness of the acrylic resin tube, white light having a broad spectrum shown in FIG. 25 can be obtained.

FIGS. 7 to 7 show a tubular semiconductor light emitting device according to the present invention.
In the third embodiment shown in FIG. 9, the semiconductor light emitting device (3)
Is a gallium nitride-based near ultraviolet LED chip having a light-emitting layer made of a gallium nitride-based compound semiconductor and having a peak emission wavelength of 365 nm to 420 nm. Also, the fluorescent substance
Excited by the light of the near-ultraviolet LED chip, the red light (re
d) A mixture of three kinds of fluorescent substances that respectively generate green light (green) and blue light (blue) (RGB phosphor)
Consists of The blue phosphor has the chemical formula: Sr ₅ (PO ₄ ) 3 C
1: represented by Eu and having an emission peak wavelength of 445 nm. The green phosphor has the chemical formula: 3 (Ba, Mg) O.8Al
₂ O ₃ : represented by Eu, Mn and having an emission peak wavelength of 514 nm. The red phosphor has the chemical formula: Y ₂ O ₂ S: Eu
And has an emission peak wavelength of 624 nm.

The fluorescent member (1) includes a cylindrical glass tube (11) as a first translucent member, an interference filter (13) provided on the outer surface of the glass tube (11), and a glass tube (11). An RGB phosphor layer (12) applied to the inner surface of (11) and a silicone resin (14) as a second translucent member filled in the glass tube (11) are provided. The interference filter (13) is an optical filter that reflects only light in a specific wavelength band using light interference and transmits light in other wavelength bands. FIG. 10 is a sectional view of an interference filter (13) using a quarter-wave multilayer film. The interference filter (13) using a quarter-wave multilayer film has a laminated structure in which light-transmitting films having a low refractive index and light-transmitting films having a high refractive index are alternately arranged. Is formed at about １ ／ of the target wavelength to be reflected. As the number of layers of the quarter-wave multilayer film increases, the reflectance increases and at the same time the spectrum width showing the high reflectance increases, so that it can be used as a filter that reflects only a specific band.

The interference filter (13) can be formed by stacking a plurality of thin films of a material having different refractive indexes on the outer surface of the glass tube (11) by an electron beam vacuum evaporation method or the like. Substances that can be used to form the interference filter (13) include, for example, metals such as aluminum, gold, silver, platinum, chromium, copper, and rhodium or silica, zirconia, titania, alumina, indium oxide, and inorganic compounds such as magnesium fluoride. Is selected from Alternatively, the interference filter (13) may be formed by stacking a plurality of liquid coating members made of a metal alkoxide such as silicon, aluminum, zirconium, titanium, and zinc by dip coating (dip coating) or the like. .

For example, when the emission peak wavelength of the LED chip is 380 nm, and the emission peak wavelengths of the blue phosphor, green phosphor and red phosphor are 445 nm, 514 nm and 624 nm, respectively, as shown in FIG. The interference filter (13) using the multilayer film reflects light emitted from the LED chip, but has a reflection spectrum characteristic that transmits light emitted from each phosphor (2). A phosphor layer (12) is a glass tube obtained by mixing a powder of a fluorescent substance with a coating member made of a liquid resin or a metal alkoxide-based coating agent and cutting the mixture into a predetermined length.
After applying to the inner surface of (11) by a method such as suction, spraying, etc., drying and heating and curing, the phosphor layer (12) is glass tube (11)
It is fixed to the inner surface of.

When assembling the semiconductor light emitting device according to the third embodiment, a silicone resin as a second translucent member is injected into the glass tube (11) from the other end of the glass tube (11). After solidification, one end and the other end of the glass tube (11) and the wiring board (2) are fixed with a sealing plug (6) using an adhesive (not shown).

The light emitted from the semiconductor light emitting device according to the third embodiment to the outside is a mixed color of blue light, green light and red light by the RGB phosphor excited by the near ultraviolet light of the semiconductor light emitting element (3). Since the light becomes light, white light having three primary color components of blue light, green light, and red light shown in FIG. 26 is obtained by appropriately controlling the mixing ratio of each phosphor substance. Of the near-ultraviolet light of the semiconductor light-emitting element (3), the light whose wavelength has been converted by the RGB phosphor is emitted to the outside without being reflected by the interference filter (13), whereas the glass tube (11 ) Is reflected inside by an interference filter (13) provided on the outer surface of the glass tube (11), and the wavelength is converted again by the phosphor layer (12). Therefore, it is possible to obtain a bright semiconductor light emitting device by converting the wavelength of the near ultraviolet light emitted from the semiconductor light emitting element (3) with the RGB phosphor with high efficiency without wasting the light.

FIGS. 11 to 16 show a fourth embodiment of the tubular semiconductor light emitting device according to the present invention. In the first to third embodiments, a structure using a semiconductor light emitting element (3) in which individual semiconductor light emitting elements (3) all separated from each other are connected to each other by a bonding wire (9) is shown. In one embodiment, a single semiconductor light emitting device having a plurality of light emitting device regions
(3). In the fourth embodiment, a semiconductor light emitting device
The components other than (3), such as the fluorescent member (1) and the fluorescent substance, are the same as those in the first to third embodiments, and a description thereof will be omitted.

The semiconductor light emitting device according to the fourth embodiment comprises a heat dissipating metal plate (15), a conductive adhesive, soldering,
Two pairs of external leads (4, 5) connected to the conductor pattern (7) by a method such as welding, and one of the two pairs of external leads (4, 5) fixed to the heat dissipation metal plate (15). Single semiconductor light-emitting device with multiple light-emitting device regions connected at the end (3)
And a fluorescent member (1) surrounding one end of the metal plate for heat radiation (15), the semiconductor light emitting element (3) and the two pairs of external leads (4, 5). The heat-dissipating metal plate (15) is made of a metal with excellent thermal conductivity such as iron, copper, and aluminum, and is plated with a highly corrosion-resistant metal, such as nickel, silver, gold, or chromium, as necessary. Is also good. Outgoing part of two pairs of external leads (4,5)
(4a, 5a) are led out of the fluorescent member (1). Fluorescent material
(1) is a fluorescent substance having a light transmitting property to light emitted from the semiconductor light emitting element (3), and absorbing light emitted from the semiconductor light emitting element (3) and converting the light to another emission wavelength. Is provided.

FIG. 14 is a schematic plan view of the fourth embodiment. The semiconductor light-emitting element (3) has a light-emitting layer made of a gallium nitride-based compound semiconductor, and is constituted by an LED chip array (16) in which gallium nitride-based LED chips having an emission wavelength peak of 365 nm to 490 nm are combined.
The LED chip array (16) is made of an insulating sapphire substrate (1
7), a conductive buffer layer (17a) provided on the sapphire substrate (17) and divided into a plurality in the plane direction, and provided on the conductive buffer layer (17a) and divided into a plurality in the plane direction. Light emitting layer (17b), a transparent electrode (17c) that transmits light emitted from the light emitting layer (17b) and electrically connects the adjacent buffer layer (17a) and light emitting layer (17b), and a sapphire substrate ( One connection electrode (P electrode) (18) provided on the transparent electrode (17c) at one end of the sapphire substrate (17) and the light-emitting layer (17b) provided on the other end of the sapphire substrate (17). Other connection electrode (N electrode)
(19). Although not particularly shown, the sapphire substrate (17) side of each light emitting layer of the LED chip array (16) is an N layer,
The transparent electrode side is the P layer. Since each light emitting layer (17b) is electrically connected by the adjacent buffer layer (17a) and the transparent electrode (17c), a plurality of semiconductor light emitting elements (3) are provided between the P electrode (18) and the N electrode (19). It is electrically equivalent to a circuit connected in series.
Therefore, the LED chip array (16) does not need to electrically connect a large number of semiconductor light emitting elements (3) to each other by the bonding wire (9), and a failure around the bonding wire (9) due to disconnection or short circuit. Therefore, a semiconductor light emitting device having high reliability and high productivity can be manufactured at low cost.

In the fourth embodiment, the fluorescent member (1) can be formed by various methods similar to those in the first to third embodiments. An LED chip array (16) is fixed to a predetermined position of the heat dissipating metal plate (15) with an adhesive (not shown), and is attached to one end and the other end of the heat dissipating metal plate (15) by a method such as wire bonding. LED chip array on the provided conductor pattern (7)
The P electrode (18) and the N electrode (19) of (16) can be connected.

When assembling the semiconductor light emitting device according to the fourth embodiment, the LED chip array (16) is fixed to the metal plate (15) for heat radiation, and the P electrode (18) of the LED chip array (16) is fixed.
After connecting the N electrode (19) and the conductor pattern (7) with the bonding wire (8), the external lead is connected to the conductor pattern (7).
Connect (4, 5). The surface of the LED chip array (16)
A protective member (not shown) such as a silicone resin may be applied to protect the semiconductor light emitting element (3) and improve light extraction efficiency. Subsequently, an adhesive (not shown) is applied to the back surface of the metal plate for heat radiation (15), and the metal plate for heat radiation (15) is inserted into a glass tube (11) which is a first translucent member. Fix it. Adhesive (not shown) to one end of glass tube (11) and metal plate (15) for heat dissipation
And fix with a sealing stopper (6). In this case, a silicone resin as a second light-transmissive member is injected into the inside from the other end of the glass tube (11) and solidified, and then the other end of the glass tube (11) and the metal plate for heat dissipation (15) are formed. The part may be fixed with a sealing plug (6) using an adhesive (not shown). Of course, the interior of the glass tube (11) may be hollowed without injecting the silicone resin.
Further, an interference filter (13) using a quarter-wave multilayer film may be formed in advance on the inner surface or the outer surface of the glass tube (11).

FIG. 17 shows a lighting circuit of the semiconductor light emitting device according to the fourth embodiment. Lighting circuit (20) shown in FIG.
Is a power supply line (21) for applying a DC power supply voltage (V _CC ).
And an LED chip array (16) connected between the power supply line (21) and the ground via the current limiting circuit (22). The forward voltage per light emitting area at the time of lighting
(V _F), the number of light-emitting region on one side of the LED chip array (16)
(n), assuming that the drive voltage of the current limiting circuit (22) is (V ₀ ),
The DC power supply voltage (V _CC ) is represented by V _CC = V _F × n + V ₀ . The output side of the current limiting circuit (22) having the input side connected to the power supply line (21) is connected to the P electrode (18) of the LED chip array (16). The current limiting circuit (22) has an action of controlling the operating current flowing through the LED chip array (16) built in the semiconductor light emitting device to a predetermined value, and for example, a constant current circuit using a field effect transistor or a bipolar transistor is preferable. But the forward voltage per light emitting region
If the DC power supply voltage (V _CC ) can be set sufficiently higher than the voltage value obtained by multiplying (V _F ) by the number (n) of light emitting regions on one side, a current limiting resistor can be used instead. In the lighting circuit (20) shown in FIG. 17, the lighting current flowing through the semiconductor light emitting device is controlled by the power supply line (2
1) From the current limiting circuit (22), to the P electrode (18) of the LED chip array (16) constituting the semiconductor light emitting device,
It flows through the semiconductor light emitting element (3) in the LED chip array (16) to the ground from the N electrode (19) of the LED chip array (16).

In the fifth embodiment of the tubular semiconductor light emitting device according to the present invention shown in FIGS. 18 to 21, a single semiconductor light emitting element having a plurality of light emitting regions as in the fourth embodiment.
Except for the semiconductor light emitting device (3), the description of the fluorescent member (1) and the fluorescent substance which are the same as those of the first to third embodiments except for the semiconductor light emitting device (3) will be omitted.

The semiconductor light emitting device according to the fifth embodiment comprises an external lead (4, 5), a heat radiating metal plate (15), and fixed to the heat radiating metal plate (15) and connected to the external lead (4, 5). A single semiconductor light-emitting element (3) having a plurality of light-emitting regions connected to one end of a metal plate (15), and a pair fixed to one end and the other end of a metal plate (15) for heat radiation. Wiring board (2), a plurality of spacers (23) fixed to the back of a pair of wiring boards (2), and a control MIC (monolithic integrated circuit) fixed to the back of a metal plate for heat dissipation (15) (24), a light intensity monitor (25) fixed to the other of the pair of wiring boards (2), and a fluorescent member (1).

One end of external leads (4, 5), metal plate for heat radiation (15), semiconductor light emitting element (3), wiring board (2), spacer
(23), control MIC (24), luminous intensity monitor (25), fluorescent member
The other end of the external lead (4, 5) is disposed inside (1), and is led out of the fluorescent member (1). The fluorescent member (1) has a light transmitting property with respect to light emitted from the semiconductor light emitting element (3), and absorbs light emitted from the semiconductor light emitting element (3) and converts the light to another emission wavelength. Material.

In the fifth embodiment, a semiconductor light emitting device
For (3), the same semiconductor light emitting device (3) as in FIG. 14 used in the fourth embodiment is used. The fluorescent member (1) is formed by the same method as in the first to third embodiments. LED
The chip array (16) is fixed to a predetermined position of the heat dissipating metal plate (15) with an adhesive (not shown), and the LED chip array (1) is fixed.
The P electrode (18) and the N electrode (19) of (6) are connected to the conductor patterns (7) provided at one end and the other end of the metal plate (15) for heat radiation by bonding wires (8). In addition, the external leads (4,
5) is connected to the conductor pattern (7). Assembling of the semiconductor light emitting device according to the fifth embodiment is performed in the same manner as in the fourth embodiment.

In the fifth embodiment, a lighting circuit for automatically controlling the lighting current of the LED chip array (16) is incorporated. The lighting circuit automatically protects against an abnormal increase in the lighting current induced by fluctuations in the ambient temperature and the DC power supply voltage _VCC of the power supply line (21), and the resulting overheating of the semiconductor light emitting element (3). It is characterized in that it has a first function and a second function of automatically adjusting the amount of light emission in response to a change in ambient brightness. Hereinafter, the internal circuit and operation of the control MIC (24) will be described.

FIG. 21 is a circuit diagram of the control MIC (24), and FIG. 22 is a terminal arrangement diagram of the control MIC (24).
FIG. 23 shows a timing chart of the control MIC (24).

The internal circuit of the control MIC (24) shown in FIG.
(30) is a constant voltage circuit (31) connected to the power supply line (21)
And heat protection (TSD: Thermal Shut Down) circuit (32)
And an automatic light control circuit (33) and a drive circuit (34). The constant voltage circuit (31) has a function of constantly supplying a constant output voltage to fluctuations in the DC power supply voltage (V _CC ), fluctuations in the load current, fluctuations in the ambient temperature, and the like. The overheat protection circuit (32) shuts off the lighting current of the LED chip array (16) when the amount of heat generated by the LED chip array (16) reaches a set temperature or more due to overcurrent or the like, thereby preventing damage due to thermal runaway. It has a function and is composed of a voltage dividing resistor (35, 36), a temperature detecting diode (37), and a comparator (38). Temperature detection diode (37)
Has a function of converting a temperature change into a voltage change by utilizing the temperature characteristic of the forward voltage V _F. The automatic dimming circuit (33) is a circuit that automatically gives a constant brightness to fluctuating ambient brightness, and includes a luminous intensity current conversion unit (40) that converts luminous intensity (Iv) to current (I). , A current-voltage converter (41) for converting the current (I) into a voltage (V), a luminous intensity reference value power supply (42), and a differential amplifier (4).
3), composed of an NPN transistor (44). The luminous intensity current converter (40) includes a photodiode (45) and a temperature correction circuit (4
6), a current mirror circuit (47) including PNP transistors (48, 49). The current-voltage converter (41)
The collector current (I ₁ ) of the PNP transistor (48) is changed by a resistor (5
0) to a detection voltage (V). Luminous intensity reference power supply (4
2) is a stabilized power supply for giving a reference value of the light quantity to be controlled. The differential amplifier (43) and the NPN transistor (44) are connected to the reference voltage of the luminous intensity reference power supply (42) and the detection voltage of the resistor (50).
(V) and LE so that the luminous intensity (I _v ) is always constant.
It has a function of controlling the lighting current (I ₅ , I ₆ ) of the D chip array (16). A driving circuit (34) for driving the LED chip array (16) has a function of supplying a lighting current to the LED chip array (16), and a current mirror circuit (51) comprising NPN transistors (52, 53) and a PNP Transistor (55, 56,
57) and a current mirror circuit (54).

The output side of the constant voltage circuit (31) whose input side is connected to the power supply line (21) of the DC power supply voltage (V _CC ) is connected via a voltage dividing resistor (35) and the emitter of a PNP transistor (48). A resistor (50), an emitter of a PNP transistor (49) and a cathode side of a photodiode (45) via a temperature correction circuit (46), and a collector of an NPN transistor (44, 52) via a resistor (58). Connected to each other. The power line (2
The PNP transistor (5) of the current mirror circuit (54) is
5, 56, 57) are connected, and a PNP transistor
The collector of (55) is connected to the collector of the NPN transistor (53), and the collector of the PNP transistor (56, 57) is connected to the LED chip array via the output terminal (24a, 24b) of the control MIC (24). (16). Also,
The output voltage of the constant voltage circuit (31) is divided by the voltage dividing resistors (35, 36) and connected to the inverting input terminal of the comparator (38). The non-inverting input terminal of the comparator (38) is grounded via a forward temperature detecting diode (37). The output terminal of the comparator (38) is connected to the collector of the NPN transistor (44, 52), and the collector of the NPN transistor (44) is connected to the collector of the NPN transistor (52) constituting the current mirror circuit (51). Is done. The collector of the NPN transistor (53) of the current mirror circuit (51) is connected to the collector of the current mirror circuit (54).

When overcurrent protection is performed by the control MIC (24), a voltage dividing resistor (3) for dividing the output voltage of the constant voltage circuit (31) is used.
5, 36 voltage (V _A) at the connection point A) of the order to be set lower than the forward voltage of the temperature detecting diode (37) (V _F), the comparator in the steady state (38), a high level And an electric current (I ₃ ) flowing through the resistor (58) is generated by the NPN transistor (44,
This corresponds to the sum of the collector current of 52). Also, due to the characteristics of the current mirror circuit (51), the collector currents (I ₄ ) of the NPN transistors (52, 53) are equal and the collector currents (I ₄ ) are equal.
₄ ) is a PNP transistor (5) of the current mirror circuit (54).
Since it is also the collector current of 5), similarly, each collector current I ₄ = I ₅ = I ₆ of the PNP transistor (55, 55, 57). By the way, the resistance value (R ₅₈ ) of the resistor ( ₅₈ ) and the NPN
The internal impedance of the transistors (44, 52) ( _R44 +
The value obtained by dividing the output voltage (V _R ) of the constant voltage circuit (31) by the sum with R ₅₂ ) is the current (I ₃ ) passing through the resistor (58). _{I 3 = V R / (R} 58 + R 44 + R 52)

Internal impedance of NPN transistor (44)
(R₄₄) And the output current of the differential amplifier (43) do not change.
If present, the current (I₃) Is a constant current and L
The lighting current (I) flowing through the ED chip array (16)₅, I₆)Also
It becomes a constant current. Overcurrent flows in the LED chip array (16)
When abnormal heat is generated, the heat is generated
Transmitted to the control MIC (24) via the
The temperature of the node (37) is increased. For temperature detection as temperature rises
Diode (37) forward voltage (V_F) Is the voltage at point A (V_A)Less than
The output voltage of the comparator (38) becomes low.
The collector voltage of the NPN transistors (44, 52) is zero.
And the NPN transistor (53) also becomes non-conductive
The current (I) of the PNP transistor (55, 55, 57)₄,
I₅, I ₆) Are all zero and the LED chip array (1
6) is protected from overcurrent.

When the control MIC (24) performs automatic dimming,
Lighting of LED chip array (16) by resistance value of anti (58)
Current (I₅, I₆) And always
It is controlled to the flow value. Automatic brightness control circuit (3
Energy saving by detecting with the photodiode (45) of 3)
Can be That is, from the LED chip array (16)
Light and light from the surrounding environment enter the photodiode (45)
Current due to the change in the internal resistance of the photodiode (45).
(I₂) Is detected as a change. Therefore, the surroundings are bright
During the day, the internal resistance of the photodiode (45) increases and LE
Reduce the illuminance of the D chip array (16)
Decreases the internal resistance of the photodiode (45) and raises the illuminance.
You. Also, the internal resistance of the photodiode (45) due to temperature changes
The resistance changes and the change in current characteristics is corrected by the temperature correction circuit (46).
can do. The temperature compensation circuit (46) is a Zener die
Combine an diode, a diode, a resistor, etc.
Cancel the temperature change of Aether (45) and change the brightness
Therefore, the current I flowing through the photodiode (45) only₂Change
There is a function to make adjustments. Current mirror circuit
Collector of PNP transistors (48, 49) constituting (47)
Current (I₁, I₂) Is I ₁= I₂Because the collector
Current (I₂Changes in (I)₁) And the voltage that changes
(I₁× R₃) Is applied to the non-inverting input terminal of the differential amplifier (43)
Is done. Luminous intensity reference value at the inverting input terminal of the differential amplifier (43)
Since the reference voltage (E) of the power supply (42) is applied, E and (I₁×
R₃) Is output from the differential amplifier (43).
The output current of the differential amplifier (43) is
Since the current flows to the base of (44), the NPN transistor (44)
The collector current changes. NPN transistor (44, 52)
The collector current of I₄₄, I₅₂Then I₃= I₄₄
+ I₅₂And the collector of the NPN transistor (52).
Data current = I₄= I₅= I₆Therefore, the photodiode
The change in the amount of incident light of (45) is the lighting power of the LED chip array (16).
The light amount is automatically adjusted by reflecting the change in the flow. Figure
23 shows a timing chart of the control MIC (24).
Even if the automatic light control circuit (33) works, the overheat protection circuit (TSD) (3
The interruption operation of 2) is prioritized.

The blue phosphor (2) has the chemical formula Sr ₅ (PO ₄ ) 3
Cl: Eu, green phosphor (2) has the chemical formula 3 (Ba, Mg) O · 8
Al ₂ O ₃ : Eu, Mn, red phosphor (2) has a chemical formula of Y ₂ O ₂ S:
Eu was exemplified, but (Ba, Ca, Mg) ₁₀ (P
O ₄ ) 6Cl ₂ : Eu (emission peak wavelength 483 nm), (Sr,
Ca, Ba) 10Cl ₂ : Eu (445 nm-452 nm), 2
SrO · 0.84P ₂ O ₅ · 0.16B ₂ O ₃ : Eu (480n
_{m), BaMg 2 Al 16 O} 2 7: Eu a (450 nm) can be used in a blue phosphor _{(2), Y 2 SiO 5} : Ce, Tb (545n
m) can be used for green phosphor (2), 3.5MgO.0.5M
gF ₂ .GeO ₂ : Mn (650 nm) can be used for the red phosphor (2).

The semiconductor light emitting elements (3) may be connected in parallel as shown in FIG. 27 instead of being connected in series. In the case of parallel connection, it is possible to avoid the problem that the entire semiconductor light emitting device is turned off even if one element is disconnected. In FIG. 27, the current limiting resistor (60) connected to the anode side of the semiconductor light emitting device (3) may be connected to the cathode side. Further, a constant current circuit may be used instead of the current limiting resistor (60). Also, connect a surge protection device including a Zener diode, ceramic varistor, and a combination of a capacitor and a resistor in parallel with the semiconductor light emitting device (3) to prevent damage to the semiconductor light emitting device (3) due to surge, external surge or static electricity. Thus, the reliability of the semiconductor light emitting device can be improved.

The shape of the first translucent member (11) is not limited to a cylindrical shape as long as it is tubular.
It can be formed in a suitable cross-sectional shape such as a quadrangle or a polygon.

In the embodiment of the present invention, the following operation and effect can be obtained. [1] 3.5 V to 4 V per semiconductor light emitting device (3)
It can operate at as low a voltage. [2] A booster circuit such as an inverter is not required, and the structure can be simplified. [3] Since it operates with direct current, there is no occurrence of high frequency noise due to the booster circuit and there is no risk of circuit malfunction. [4] Low heat generation and easy thermal design. [5] It is hardly affected by the ambient temperature and can operate stably immediately after power is applied. [6] The dimensions of the members of the semiconductor light emitting element (3) and the like can be reduced as much as possible, and the size can be reduced. [7] Contains no harmful substances such as mercury and does not pollute the environment. Therefore, by using the semiconductor light emitting device according to the present invention, it is possible to provide an excellent solid-state light source that solves many disadvantages of the cold cathode fluorescent tube.

[0051]

As described above, the semiconductor light emitting device according to the present invention does not use a booster circuit that generates high-frequency noise.
A semiconductor light emitting device with less heat dissipation can be realized.
Further, the semiconductor light emitting device according to the present invention can realize a semiconductor light emitting device which can be reduced in diameter without affecting lighting conditions depending on environmental conditions to be used and which does not use mercury which generates environmental pollution.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of a semiconductor light emitting device according to the present invention.

FIG. 2 is a cross-sectional view along the length direction of FIG.

FIG. 3 is a sectional view along the radial direction of FIG. 1;

FIG. 4 is a plan view showing a second embodiment of the semiconductor light emitting device according to the present invention.

FIG. 5 is a sectional view along the length direction of FIG. 4;

6 is a sectional view taken along the radial direction of FIG.

FIG. 7 is a plan view showing a third embodiment of the semiconductor light emitting device according to the present invention.

FIG. 8 is a sectional view along the length direction of FIG. 7;

9 is a sectional view taken along the radial direction of FIG. 7;

FIG. 10 is a sectional view of an interference filter.

FIG. 11 is a plan view showing a fourth embodiment of the semiconductor light emitting device according to the present invention.

FIG. 12 is a cross-sectional view along the length direction of FIG. 11;

FIG. 13 is a sectional view taken along the radial direction of FIG. 11;

FIG. 14 is a side view of the semiconductor light emitting device shown in FIG. 11;

FIG. 15 is a plan view of the semiconductor light emitting device shown in FIG. 11;

16 is a circuit configuration diagram of the semiconductor light emitting device shown in FIG.

FIG. 17 is a lighting circuit diagram of the semiconductor light emitting device according to the fourth embodiment.

FIG. 18 is a plan view showing a fifth embodiment of the semiconductor light emitting device according to the present invention.

19 is a side view of FIG.

20 is a bottom view of FIG.

FIG. 21 is a circuit diagram of a control MIC.

FIG. 22 is a terminal arrangement diagram of a control MIC.

FIG. 23 is a timing chart of a control MIC.

FIG. 24 shows an example of a reflection spectrum of an interference filter.

FIG. 25 shows first and second semiconductor light emitting devices according to the present invention.
Emission spectrum of the embodiment

FIG. 26 shows an emission spectrum of the semiconductor light emitting device according to the third embodiment of the present invention.

FIG. 27 is a schematic view of parallel connection of semiconductor light emitting elements.

FIG. 28 is a schematic sectional view of a conventional cold cathode fluorescent tube.

[Explanation of symbols]

(1) ・ ・ Fluorescent material, (3) ・ ・ Semiconductor light emitting device, (4, 5)
..External leads, (4a, 5a)
・ Terminal part, (11) ・ ・ First translucent member (glass tube),
(12) ... Phosphor layer, (13) ... Interference filter, (14)
..Second translucent member, (32)
3) ・ ・ Automatic dimming circuit,

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F21S 2/00 F21V 9/16 8/04 H05B 37/02 D F21V 9/16 F21S 1/02 G H05B 37 / 02 1/00 D (72) Inventor Takeshi Sano 3-6-3 Kitano, Niiza City, Saitama Prefecture Within Sanken Electric Co., Ltd. (72) Inventor Nobuo Kobayashi 3-6-3 Kitano, Niiza City, Saitama Prefecture Sanken Within Electric Co., Ltd. (72) Inventor Yasuhiro Maruo 3-6-3 Kitano, Niiza-shi, Saitama F-term (reference) within Sanken Electric Co., Ltd. 3K073 AA67 AA83 BA28 BA31 CF13 CG42 CJ17 CJ22 4H001 CA01 XA07 XA08 XA13 XA31 XA39 XA64 YA58 5F041 BB10 BB13 BB22 BB26 CA40 DA07 DA13 DA75 DA83 DB09 EE22 EE25 FF11

Claims (16)

[Claims] A tubular fluorescent member (1), a semiconductor light emitting element (3) disposed in the fluorescent member (1), and the semiconductor light emitting element (3) fixed to both ends of the fluorescent member (1). ) And a plurality of external leads (4, 5) electrically connected to each other, and each of the external leads (4, 5) is a lead-out portion (4a, 4) extending outside the fluorescent member (1). 5a), and a terminal portion (4b, 5b) disposed inside the fluorescent member (1) and electrically connected to the semiconductor light emitting element (3), wherein the fluorescent member (1) is The semiconductor light emitting device has a light transmitting property to light emitted from the semiconductor light emitting device (3) and the semiconductor light emitting device
(3) A semiconductor light-emitting device comprising a fluorescent substance that absorbs light emitted from (3) and converts the light into another emission wavelength. 2. The semiconductor according to claim 1, wherein the semiconductor light-emitting element is a gallium nitride-based LED chip having a light-emitting layer made of a gallium nitride-based compound semiconductor and having a peak emission wavelength of 420 nm to 490 nm. Light emitting device. 3. The fluorescent substance has a chemical formula (Y _1-x , G
_{d x) 3 (Al 1-} y, Ga y) 5 O 12: Ce z ( where in claim 1 or 2 represented by 0 ≦ x ≦ 0.5,0 ≦ y ≦ 0.5,0.001 ≦ z ≦ 0.5) 14. The semiconductor light emitting device according to claim 1. 4. The semiconductor light-emitting device (3) is a gallium nitride-based LED chip having a light-emitting layer made of a gallium nitride-based compound semiconductor and having a peak emission wavelength of 365 nm to 420 nm; A blue fluorescent substance having an emission peak at 490 nm to 490 nm, a green fluorescent substance having an emission peak at 520 nm to 570 nm, and a red fluorescent substance having an emission peak at 590 nm to 700 nm, and emitted from the semiconductor light emitting element (3). The semiconductor light emitting device according to claim 1, wherein an interference filter (13) that reflects light of a certain wavelength and transmits light of a wavelength emitted from the phosphor is formed on an outer surface or an inner surface of the fluorescent member (1). 5. The fluorescent member (1) includes a first light-transmitting member (11) formed in a tubular shape, and an inner surface of the first light-transmitting member (11) coated with the fluorescent material. 5. The semiconductor light emitting device according to claim 1, further comprising: a phosphor layer. 6. The first light-transmissive member (11), wherein the first fluorescent member (1) includes the fluorescent substance therein and is formed in a tubular shape.
The semiconductor light emitting device according to claim 1, further comprising: 7. The fluorescent member (1) includes a first light-transmitting member (11) formed in a tubular shape, and a second light-transmitting member (11) filled inside the first light-transmitting member (11). The semiconductor light emitting device according to any one of claims 1 to 4, further comprising a light transmitting member (14), wherein the fluorescent material is applied or contained on the first light transmitting member (11). 8. The fluorescent member (1) includes a first translucent member (11) formed in a tubular shape, and a second translucent member (11) filled in the first translucent member (11). The semiconductor light emitting device according to any one of claims 1 to 4, comprising a light-transmitting member (14), wherein the fluorescent material is blended in the second light-transmitting member (14). 9. The first light-transmissive member (11) is made of glass or resin having light transmissivity.
The semiconductor light emitting device according to claim 1. 10. The semiconductor light emitting device according to claim 7, wherein the second light transmitting member is a resin having light transmitting property. 11. An interference filter (13) that reflects light of a wavelength radiated from the semiconductor light emitting element (3) and transmits light of a wavelength radiated from the fluorescent substance is provided on the tubular fluorescent member.
The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is formed on an outer surface or an inner surface of (1). 12. The semiconductor light emitting device according to claim 1, wherein a light reflecting portion is formed on a part of an outer surface of said fluorescent member. 13. The semiconductor light emitting device (3), wherein:
The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is arranged along a length direction of an inner surface of the light transmitting member. 14. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting element is disposed in a length direction between one end and the other end of the fluorescent member. 13. The semiconductor light emitting device according to item 9. 15. Detecting light from the semiconductor light emitting element (3) and surrounding external light, adjusting the amount of light emitted from the semiconductor light emitting element (3) in accordance with increase or decrease of the external light, so as to always maintain a constant brightness. The semiconductor light emitting device according to any one of claims 1 to 14, further comprising an automatic dimming circuit (33) for keeping. 16. When the temperature of the semiconductor light emitting device (3) reaches a preset limit value, the semiconductor light emitting device (3)
The semiconductor light emitting device according to any one of claims 1 to 15, further comprising an overheat protection circuit (32) that automatically shuts off the lighting current of (3).