JP2004055742A - Light-emitting device and light-emitting device array equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device array, which realizes a high resolution by a light-emitting device having proper accuracy of arraying and by providing the same. <P>SOLUTION: Individual light-emitting units 101, 102, 103 are formed in the light-emitting device 100 and the individual light-emitting unit 101 is an individual light-emitting unit for red color, while the individual light-emitting unit 102 is an individual light-emitting unit for green color and the individual light-emitting unit 103 is an individual light-emitting unit for blue color. Translucent resins 151, 152, 153, containing a phosphorous body which emits a color coping with the light-emitting color of respective individual light-emitting units by the ultraviolet light, are formed on the surfaces of the individual light-emitting units 101, 102, 103 so as to be disposed near individual P side electrodes 104 formed in respective individual light-emitting units. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting device used for an LED printer and a light emitting device array including the same.
[0002]
[Prior art]
In recent years, a light emitting element array has been used as a light source of an electrophotographic optical printer. This light-emitting element array is a semiconductor light-emitting device in which a plurality of light-emitting elements are arranged on a single semiconductor substrate at one-dimensional intervals. Conventionally, as a light emitting element array, a semiconductor laser array using a semiconductor laser as a light emitting element and an LED array using a light emitting diode (Light Emitting Diode; hereinafter, referred to as “LED”) as a light emitting element are used. Have been.
[0003]
Here, full-color display using LEDs has conventionally been performed by arranging three types of LED chips emitting red, green, and blue in one element.
[0004]
FIG. 6 is a schematic plan view of a multicolor light emitting device 200 according to a conventional example, and FIG. 7 is a sectional view of the multicolor light emitting device 200 according to the conventional example of FIG. As shown in the figure, the multicolor light emitting element 200 has a red LED chip 201, a blue LED chip 202, and a green LED chip 203 arranged on a common substrate 204, and a full-color display is performed by a combination of respective light emitting colors. That can be done.
[0005]
[Problems to be solved by the invention]
However, in this conventional full-color display, since three types of LED chips are arranged in one element, the size of one pixel is 5 to 10 mm. As a result, when attempting to display at high resolution with such large pixels, the full-color display device becomes large, and it is difficult to cope with high-density mounting. Further, as described above, since three types of LED chips are arranged in one element, there is a problem that the arrangement accuracy is poor.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, a light-emitting element according to the present invention includes a plurality of independent individual light-emitting units having different emission colors, and individual electrodes formed on a part of the plurality of individual light-emitting units. Further, a common electrode commonly used for a plurality of individual light emitting units is formed.
[0007]
Further, in the light emitting element according to the present invention, a translucent resin containing a phosphor that emits a color corresponding to each of the individual light emitting units by ultraviolet light is formed on the surface of the plurality of individual light emitting units.
[0008]
In addition, the light emitting element array according to the present invention is formed on a semiconductor substrate and includes a semiconductor layer on which a plurality of light emitting elements are formed. A plurality of blocks each including an individual light emitting unit including a light emitting unit, an individual electrode formed on a part of each of the individual light emitting units, and a common electrode commonly used for the individual light emitting unit are formed. The formed individual light-emitting portions are electrically connected by wiring for each emission color via individual electrodes, and are also connected by wiring to other common electrodes provided on the substrate for each emission color. You.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view schematically showing a light emitting device according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along a line aa in FIG. FIG. 3 is a side view schematically showing a light emitting device according to the first embodiment of the present invention.
[0010]
The light emitting device 100 includes three individual light emitting units 101, 102, and 103 each having a p / n epitaxial layer 108 arranged in a row on a semiconductor substrate 107. Each individual light emitting unit includes an individual P light emitting unit. A mold electrode 104 is formed.
[0011]
Here, the semiconductor layer 108 formed on the semiconductor substrate 107 uses, for example, a gallium nitride-based compound semiconductor, and an N-type GaN layer, an active layer, and a P-type GaN layer are sequentially grown by epitaxial growth. Things. Note that the semiconductor layer may be formed using InGaN as another gallium nitride-based compound.
[0012]
Among these individual light emitting units 101, 102, and 103, the individual light emitting unit 101 is an individual light emitting unit for red, the individual light emitting unit 102 is an individual light emitting unit for green, and the individual light emitting unit 103 is an individual light emitting unit for blue. . The individual P-side electrode 104 formed in each individual light emitting unit is electrically connected to the upper P layer 109 side of the semiconductor layer 108 formed on the semiconductor substrate 107 by the epitaxial growth method. I have.
[0013]
On each surface of the individual light emitting units 101, 102, and 103, a translucent resin 151, 152, and 153 containing a phosphor that emits a color corresponding to the emission color of each individual light emitting unit by ultraviolet light is provided. It is formed adjacent to the individual P-side electrode formed in the individual light emitting section. Here, the phosphor that emits a color corresponding to the emission color of each individual light emitting portion by ultraviolet light, for example, when the above-mentioned GaN is used as a semiconductor material, the wavelength of the ultraviolet light emitted from the GaN semiconductor is changed to another wavelength. Any kind of fluorescent paint, fluorescent pigment, phosphor, or the like that converts the light into a wavelength and emits a color corresponding to the emission color of each individual light emitting unit may be used. Further, the translucent resins 151, 152, 153 containing the phosphor can contain the above-mentioned phosphor inside and can be arranged on the light emitting element. For example, an alicyclic epoxy resin, A thermosetting resin such as a nitrogen-containing epoxy resin may be used.
[0014]
That is, when the light-emitting element 100 is used as a multicolor light-emitting element for a display device, the surface of the individual light-emitting section 101 for red is excited by ultraviolet light emitted from the GaN semiconductor and emits light at 610 to 700 nm. A translucent resin 151 containing a phosphor that emits a wavelength having a peak is formed, and the surface of the green individual light emitting unit 102 is excited by ultraviolet light emitted from the GaN semiconductor to 495 to 565 nm. A translucent resin 152 containing a phosphor emitting a wavelength having an emission peak is formed, and the surface of the individual light emitting portion 103 for blue is excited by ultraviolet light emitted from the GaN semiconductor to reach 430 to 490 nm. Then, a light-transmitting resin 153 containing a phosphor that emits light having a wavelength having an emission peak is formed.
[0015]
The light-emitting element 100 has a common N-side electrode 105 used in common for the three individual light-emitting portions 101, 102, and 103. The common N-side electrode 105 is epitaxially grown on a semiconductor substrate 107. It is electrically connected to the lower N layer 110 side of the semiconductor layer 108 formed by the method.
[0016]
A light-shielding film 106 is formed on the surface of the light-emitting element 100 other than the individual light-emitting portions 101, 102, 103 and the common N-side electrode 105. Blurring of light emitted from 101, 102, and 103 can be effectively prevented. In order to further improve light bleeding, it is preferable to provide a reflection layer (not shown) made of, for example, SiO ₂ between the semiconductor layer and the semiconductor substrate.
[0017]
As shown in FIG. 3, in the P layer 109 located above the semiconductor layer 108, a separation groove 112 for separating the individual light emitting units 101, 102, and 103 is formed. A film is formed so as to cover 112. Thereby, the individual light emitting units 101, 102, and 103 can be physically and electrically separated from each other.
[0018]
In the first embodiment, the individual light emitting units 101, 102, and 103 are arranged in a line in the horizontal direction. However, these individual light emitting units may be arranged at any position on the light emitting element 100. good.
[0019]
Next, an example of a manufacturing process of the light emitting device 100 according to the first embodiment of the present invention will be described with reference to FIGS.
[0020]
First, in the present manufacturing method, a semiconductor layer 108 is formed on a semiconductor substrate 107 as shown in FIG. Here, as the semiconductor substrate 107, for example, a high-resistance GaN substrate is used. The semiconductor layer 108 uses, for example, a gallium nitride-based compound semiconductor, and is formed by sequentially growing an N-type GaN layer, an active layer, and a P-type GaN layer by an epitaxial growth method. Note that the semiconductor layer may be formed using InGaN as another gallium nitride-based compound.
[0021]
Here, the epitaxial growth method is a method for growing a crystal film on a substrate, and includes an LPE (liquid phase epitaxial) method, a VPE (vapor phase epitaxial) method, a CVD (chemical vapor deposition) method, and a MOVPE (organic vapor phase) method. Metal vapor phase epitaxy), MOCVD (metal organic chemical vapor deposition), Halide-VPE (halogen chemical vapor phase epitaxy), MBE (molecular beam epitaxy), MOMBE (organometallic molecular beam epitaxy), GSMBE (Gas source molecular beam epitaxy) and CBE (chemical beam epitaxy). The thickness of the semiconductor layer 109 is, for example, 3 μm.
[0022]
When forming the semiconductor layer 108 on the semiconductor substrate 107, the semiconductor layers are formed in the order of N-type and P-type. Therefore, in the semiconductor layer 108, the upper layer 109 is P-type and the lower layer 110 is N-type. Here, the P layer 109 of GaN is doped with Cp ₂ Mg (biscyclopentadienyl magnesium) at the time of the epitaxial growth, and dissociates hydrogen by alloy processing (for example, at 700 ° C. for 20 minutes) described later. Thereby, Mg can be activated and obtained.
[0023]
Further, the semiconductor substrate 107 and the semiconductor layer 108 are electrically insulated, and a method for performing the insulation is a method using a high-resistance semiconductor substrate (for example, a high-resistance GaN substrate) as the semiconductor substrate, a P-type semiconductor. A method using a substrate, a method of forming an insulating layer between the semiconductor substrate 107 and the semiconductor layer 108, and the like.
[0024]
Next, the individual light emitting units 101, 102, and 103 are formed on the semiconductor layer 108 by photolithography or etching. Here, a metal film (for example, gold) that does not transmit hydrogen is formed on the surface of the semiconductor layer 108, and after removing metal in regions corresponding to the individual light emitting units 101, 102, and 103 by photolithography or etching, By performing the alloy processing, only the regions of the individual light emitting units 101, 102, and 103 become P-type and can emit light independently.
[0025]
At this time, as shown in FIG. 2, in a region other than the portion where the individual light emitting portions 101, 102, and 103 are formed on the surface of the semiconductor layer 108, photolithography is performed so that the lower N layer 110 is exposed. Or etching is performed. In addition, as shown in FIG. 3, a separation groove 112 may be formed in the semiconductor layer 108 to separate the individual light emitting units 101, 102, and 103 from each other. The separation groove 112 is formed at a depth reaching the lower N layer 110 as shown in FIG.
[0026]
Next, a pattern is formed by a lift-off method, and an individual P-side electrode 104 is formed on a part of the individual light emitting units 101, 102, and 103 by film formation. The electrode material may be any material that can be ohmic-connected to the semiconductor. For example, an Au laminated film such as Ni (200 Å) / Au (1.2 μm) can be used.
[0027]
Next, also for the formation of the common N-side electrode 105, a pattern is formed by a lift-off method, and the common N-side electrode 105 is formed on the exposed lower N layer 110 on the surface of the semiconductor layer 108. Here, the electrode material may be any material that can be ohmic-connected to the semiconductor. For example, an Au alloy film such as Ti (200 Å) / Au (1.2 μm) can be used.
[0028]
Next, as shown in FIG. 1, a light-shielding film 106 is formed on the surface of the light-emitting element 100, and the surfaces of the individual light-emitting portions 101, 102, and 103 and the N-side common electrode 105 are opened and exposed. Here, the opening can be formed by, for example, photolithography and etching. The material of the light-shielding film 106 may be any material as long as it has good adhesion to the semiconductor and is insulative. For example, there is a black resist used for a color filter of an LCD.
[0029]
Next, a light-transmitting resin in which a phosphor is dispersed is applied by printing on the surface of the individual light emitting units 101, 102, and 103, and contains a phosphor that emits a color corresponding to each of the individual light emitting units 101, 102, and 103. The transparent resin 151, 152, 153 thus formed is formed. The translucent resins 151, 152, 153 can also be formed of a fluorescent material-containing sheet. Alternatively, the translucent resins 151, 152, and 153 containing a phosphor can be sequentially formed by photolithography or etching.
[0030]
Next, a sintering process (heat treatment) for making an ohmic connection between the electrode and the semiconductor layer 108 is performed, and the back surface of the semiconductor substrate 107 is polished as necessary. Then, the light emitting device 100 shown in FIG. 2 is manufactured.
[0031]
As described above, in this embodiment, the translucent resin 151 containing the phosphor that emits red, green, and blue light by ultraviolet light is provided on the surface of the individual light emitting units 101, 102, and 103 of the light emitting element 100. Since the layers 152 and 153 are coated, it is possible to provide a light emitting element having better alignment accuracy as compared to a case where three types of LED chips are arranged in one element.
[0032]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 4 is a plan view schematically showing a light emitting element array according to the second embodiment of the present invention, and FIG. 5 is a sectional view taken along a line aa in FIG.
[0033]
In the light emitting element array 150, three blocks 129, 130, and 131 are formed on the semiconductor substrate 107, with the light emitting element 100 described in the first embodiment as one block. The number of blocks formed on the semiconductor substrate may be any number as long as it is two or more.
[0034]
The three individual light emitting units of red, green, and blue formed in each of the blocks 129, 130, and 131 are electrically connected to the red, green, and blue individual light emitting units of the other blocks by wiring. That is, the red light emitting unit 101 of the block 129 is connected to the individual wiring 116, and the red light emitting unit 101 is connected to the individual wiring 117 via the common wiring 119. And the red light emitting section 144 of the block 131 connected to the individual wiring 118. Further, a red common P-side electrode 113 is formed on the semiconductor substrate 107, and the red common P-side electrode 113 is formed in each block via a common wiring 119 and individual wirings 116, 117, and 118. Red light emitting units 101, 141, 144.
[0035]
Similarly, the green light emitting unit 102 of the block 129 is connected to the individual wiring 120, and the green light emitting unit 102 is connected to the green light emitting unit 142 of the block 130 connected to the individual wiring 121 via the common wiring 123. , And the green light emitting portion 145 of the block 131 connected to the individual wiring 122. In addition, a green common P-side electrode 114 is formed on the semiconductor substrate 107, and the green common P-side electrode 114 is formed in each block via a common wiring 123 and individual wirings 120, 121, and 122. The green light emitting units 102, 142, and 145 are electrically connected.
[0036]
Similarly, the blue light emitting section 103 of the block 129 is connected to the individual wiring 124, and the blue light emitting section 103 is connected to the individual wiring 125 via the common wiring 127. 143 and the blue light emitting portion 146 of the block 131 connected to the individual wiring 126. Further, a blue common P-side electrode 115 is formed on the semiconductor substrate 107, and the blue common P-side electrode 115 is formed in each block via a common wiring 127 and individual wirings 124, 125, and 126. Are electrically connected to the blue light emitting units 103, 143, and 146.
[0037]
The three light emitting portions of red, green, and blue formed in each block are formed at a pitch of, for example, 30 μm, and each block is formed at a pitch of, for example, 90 μm. In this case, a multicolor light emitting element array having a resolution of 300 dpi is formed.
[0038]
As shown in FIG. 4, in order to effectively prevent bleeding of light emitted from the adjacent individual light emitting units, the individual light emitting units and the common N side of the surfaces of the blocks 129, 130, and 131 are used. The light-shielding film 106 is formed on the surface other than the region where the electrodes are formed. In order to further improve the bleeding of light, a reflective layer made of, for example, SiO _{2 is provided} between the semiconductor layer and the semiconductor substrate. (Not shown) is preferably provided. In order to more effectively prevent light bleeding, a light-shielding film 106 is also formed on the surface of the semiconductor substrate 107 other than the region where the common P-side electrodes 113, 114, and 115 are formed. ing.
[0039]
Further, as in the first embodiment, the semiconductor substrate 107 and the semiconductor layer 108 are electrically insulated, and a method for performing the insulation is performed by using a high-resistance semiconductor substrate (for example, a high-resistance GaN substrate). ), A method using a P-type semiconductor substrate, a method of forming an insulating layer 128 between the semiconductor substrate 107 and the semiconductor layer 108, and the like.
[0040]
The blocks 129, 130, and 131 are electrically separated from each other by a separation groove 132 formed in the N layer 110. Thus, the blocks 129, 130, 131 can be physically and electrically separated.
[0041]
In the second embodiment, as shown in FIG. 4, the individual light emitting units formed in each of the blocks 129, 130, and 131 are arranged in a horizontal direction. However, these individual light emitting units are arranged at arbitrary positions. Can be arranged.
[0042]
As described above, in the present embodiment, the light-emitting element array 150 is formed by arranging a plurality of blocks including light-emitting elements having individual alignment units for each of red, green, and blue and having high alignment accuracy. Since the three individual light emitting units of red, green, and blue formed in each of the blocks 129, 130, and 131 are electrically connected to the red, green, and blue individual light emitting units of the other blocks by wiring, It is possible to provide a high-resolution light-emitting element array with extremely high alignment accuracy and capable of independently emitting red, green, and blue light.
[0043]
It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.
[0044]
For example, in the embodiment of the present invention, the case where the LED array is used as the light emitting element array has been described. However, the light emitting element is not limited to this, and another element such as a light emitting laser can be used.
[0045]
Further, the material, composition, and the like of the substrate, the electrode, the impurities, and the like are not limited to those of the embodiments, and other materials can be selected.
[0046]
For example, in the above embodiment, a GaN substrate is used as a semiconductor substrate, but other substrates, for example, a Si substrate, SiC, sapphire (Si ₂ O ₃ ), spinel, ZnO, or the like can be used.
[0047]
【The invention's effect】
As described in detail above, according to the present invention, a red, green, and blue light-emitting element array is formed by arranging a plurality of blocks each including a light-emitting element having an individual light-emitting unit and having high alignment accuracy, and In addition, since the three individual light emitting units of red, green, and blue formed in each block are electrically connected to the individual light emitting units of red, green, and blue of the other blocks by wiring, the arrangement accuracy is extremely high. It is possible to provide a high-resolution light-emitting element array that can emit light in red, green, and blue independently.
[0048]
Further, by arranging the light emitting element arrays in a line and combining the light emitting element arrays with a driving circuit, it is possible to provide an LED print head capable of emitting multicolor light. In addition, by using this print head, it is possible to output a color photograph by directly exposing and developing a photographic paper or the like.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing a light emitting device according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line aa of the schematic plan view shown in FIG.
FIG. 3 is a side view schematically showing a light emitting device according to the first embodiment of the present invention.
FIG. 4 is a plan view schematically showing a light emitting element array according to a second embodiment of the present invention.
FIG. 5 is a sectional view taken along line aa of the schematic plan view shown in FIG. 4;
FIG. 6 is a schematic plan view of a conventional multicolor light emitting device.
FIG. 7 is a sectional view taken along the line aa of the schematic plan view shown in FIG. 6;
[Explanation of symbols]
100: Light emitting element 101: Red individual light emitting part 102: Green individual light emitting part 103: Blue individual light emitting part 104: Individual P electrode 105: Common N electrode 106: Light shielding film 107: Semiconductor substrate 108: Semiconductor layer 111: Translucent resin 113, 114, 115: common P electrode 128: insulating film 129, 130, 131: block

Claims (11)

A light emitting element having a plurality of independent individual light emitting units having different emission colors, individual electrodes formed in a part of the individual light emitting units, and a common electrode commonly used for the plurality of individual light emitting units. The light-emitting device according to claim 1, wherein a light-transmitting resin containing a phosphor that emits a color corresponding to each of the individual light emitting units by ultraviolet light is formed on a surface of the plurality of individual light emitting units. element. The light-transmitting resin is formed adjacent to the individual electrode, and the common electrode is connected to an N-layer side of a semiconductor layer provided on a semiconductor substrate. Item 3. The light emitting device according to item 1 or 2. The light emitting device according to claim 1, wherein a light shielding film is formed on a surface of the light emitting device other than the individual light emitting unit and the common electrode. The light emitting device according to claim 1, 2, 3, or 4, wherein the plurality of individual light emitting units include a red light emitting unit, a green light emitting unit, and a blue light emitting unit. In a light emitting element array formed on a semiconductor substrate and including a semiconductor layer on which a plurality of light emitting elements are formed, on the semiconductor substrate, a red light emitting section, a blue light emitting section, an individual light emitting section including a green light emitting section, A plurality of blocks each including an individual electrode formed on a part of each of the individual light emitting units and a common electrode commonly used for the individual light emitting units are formed, and the individual light emitting unit formed on each block is formed. Are electrically connected by wiring for each emission color via the individual electrode, and are connected by wiring to another common electrode provided on the substrate for each emission color. Light emitting element array. 7. The light emitting device according to claim 6, wherein a translucent resin containing a phosphor that emits a color corresponding to each of the individual light emitting units by ultraviolet light is formed on a surface of the plurality of individual light emitting units. array. The light-transmitting resin is formed adjacent to the individual electrode, and the common electrode is connected to an N-layer side of a semiconductor layer provided on a semiconductor substrate. Item 8. The light emitting element array according to item 6 or 7. 9. The light emission according to claim 6, wherein a light-shielding film is formed on a surface of the light emitting element other than the individual light emitting unit and the common electrode, and a surface of the semiconductor substrate other than the other common electrode. Element array. 9. The semiconductor device according to claim 6, wherein the plurality of blocks are electrically separated from each other by a separation groove formed in the semiconductor layer, and are electrically insulated from the semiconductor substrate. Or the light-emitting element array according to 9. The light emitting element array according to claim 6, wherein a reflection layer is provided between the semiconductor substrate and the semiconductor layer.

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