(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0020077 A1
`Horiuchi et al.
`(43) Pub. Date:
`Jan. 30, 2003
`
`US 2003.0020077A1
`
`(54) LIGHT EMITTING DIODE DEVICE
`(75) Inventors: Megumi Horiuchi, Yamanashi-ken (JP);
`Shinobu Nakamura, Yamanashi-ken
`(JP)
`
`Foreign Application Priority Data
`(30)
`Jul. 25, 2001 (JP)...................................... 2001-225211
`Publication Classification
`
`Correspondence Address:
`Ira J. Schultz
`ENNISON, SCHULTZ & DOUGHERTY
`1745 Jefferson Davis Highway
`Arlington, VA 22202 (US)
`
`(73) Assignee: Citizen Electronics Co., Ltd.
`(21) Appl. No.:
`10/199,298
`
`(22) Filed:
`
`Jul. 22, 2002
`
`(51) Int. Cl. ............................................. H01L 27/15
`(52) U.S. Cl. ................................................................ 257/81
`(57)
`ABSTRACT
`A light emitting diode device has a reflector member having
`an approximately Semispherical receSS. A reflector Surface is
`provided on an inner Surface of the receSS and a light
`emitting diode is provided in the receSS. The light emitting
`diode is located at a position So that a part of light beams
`emitted from the light emitting diode recedes from an optical
`axis, and another part of the light beams approaches to the
`optical axis.
`
`
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`Nichia Exhibit 1009
`Page 1
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`Patent Application Publication Jan. 30, 2003 Sheet 1 of 13
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`US 2003/0020077 A1
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`FIG. 1
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`Page 2
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`Patent Application Publication Jan. 30, 2003 Sheet 2 of 13
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`US 2003/0020077 A1
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`Nichia Exhibit 1009
`Page 3
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`Patent Application Publication Jan. 30, 2003 Sheet 3 of 13
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`US 2003/0020077 A1
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`FIG. 5
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`
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`FIG. 6
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`Nichia Exhibit 1009
`Page 4
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`Patent Application Publication Jan. 30, 2003 Sheet 4 of 13
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`US 2003/0020077 A1
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`FIG. 7
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`Nichia Exhibit 1009
`Page 5
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`

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`Patent Application Publication Jan. 30, 2003 Sheet 5 of 13
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`US 2003/0020077 A1
`
`FIG 11
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`Nichia Exhibit 1009
`Page 6
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`Patent Application Publication Jan. 30, 2003 Sheet 6 of 13
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`US 2003/0020077 A1
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`Nichia Exhibit 1009
`Page 7
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`Patent Application Publication Jan. 30, 2003 Sheet 7 of 13
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`US 2003/0020077 A1
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`Nichia Exhibit 1009
`Page 8
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`Patent Application Publication Jan. 30, 2003 Sheet 8 of 13
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`US 2003/0020077 A1
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`FIG. 17
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`Nichia Exhibit 1009
`Page 9
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`Patent Application Publication Jan. 30, 2003 Sheet 9 of 13
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`US 2003/0020077 A1
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`FIG. 20
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`Nichia Exhibit 1009
`Page 10
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`Patent Application Publication Jan. 30, 2003 Sheet 10 of 13 US 2003/0020077 A1
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`
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`Nichia Exhibit 1009
`Page 11
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`Patent Application Publication Jan. 30, 2003 Sheet 11 of 13 US 2003/0020077 A1
`
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`Nichia Exhibit 1009
`Page 12
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`Patent Application Publication
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`Jan. 30, 2003 Sheet 12 of 13
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`US 2003/0020077 A1
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`FIG. 26
`PRIOR ART
`110
`
`FIG. 27
`PRIOR ART
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`
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`Page 13
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`Patent Application Publication Jan. 30, 2003 Sheet 13 of 13 US 2003/0020077 A1
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`FIG. 28
`PRIOR ART
`
`FIG. 29
`PRIOR ART
`
`116
`
`:
`
`Nichia Exhibit 1009
`Page 14
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`

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`US 2003/0020077 A1
`
`Jan. 30, 2003
`
`LIGHT EMITTING DODE DEVICE
`
`BACKGROUND OF THE INVENTION
`0001. The present invention relates to a light emitting
`diode device having a light emitting diode and provided for
`an electronic equipment, and more particularly to a light
`emitting diode device having a reflector.
`0002 FIG. 26 is a perspective view showing a conven
`tional light emitting diode device, and FIG. 27 is a sectional
`View of the light emitting diode device.
`0003. The light emitting diode device comprises a Sub
`Strate 101 made of an epoxy resin, a cathode electrode
`pattern 102 and an anode electrode pattern 103 formed on
`the upper surface of the substrate 101. These patterns 102
`and 103 are connected to underside patterns 102a and 103a
`through leads 104 provided in through-holes.
`0004 A light emitting diode 105 is securely mounted on
`the cathode electrode pattern 102. The light emitting diode
`105 is connected to the anode electrode pattern 103 by a
`bonding wire 109. A cylindrical reflector 106 is mounted on
`the Substrate 101 Surrounding the light emitting diode 105.
`An inner reflecting wall 107 has an inverted truncated cone
`shape, so that the light 108 emitted from the light emitting
`diode 105 in horizontal directions is reflected in vertical
`directions.
`0005) The light emitting diode (LED) 105, reflector 106,
`and bonding wire 109 are Sealed by a Sealing member 110
`made of a transmissive resin.
`0006 The sealing member 110 has a semispherical lens
`110b. The semispherical lens 110b is provided for condens
`ing the light 108 into light 108b.
`0007 FIG. 28 is a perspective view showing another
`reflector, and FIG. 29 is a sectional view of the reflector.
`0008. The reflector 116 has a semispherical reflecting
`wall 117 so as to parallely reflect the light emitted from the
`LED 105 in vertical direction.
`0009. Although the light emitting diode device illumi
`nates a Small area, the device can not light a large area.
`Therefore, the device can not be used as an edge light for
`irradiating a panel.
`
`SUMMARY OF THE INVENTION
`0010. An object of the present invention is to provide a
`light emitting diode device which may irradiate a wide area.
`0011. According to the present invention, there is pro
`Vided a light emitting diode device comprising a reflector
`member having an approximately Semispherical receSS, a
`reflector Surface provided on an inner Surface of the receSS,
`a light emitting diode provided in the receSS, and the light
`emitting diode being located at a position So that a part of
`light beams emitted from the light emitting diode recedes
`from an optical axis, and another part of the light beams
`approaches to the optical axis.
`0012. In an aspect of the present invention, the device
`comprises a Substrate, and the reflector member being
`mounted on the Substrate.
`
`0013 The reflector surface includes a first reflector Sur
`face about an X-axis and a Second reflector Surface about a
`Y-axis.
`In another aspect, the first reflector Surface and the
`0014.
`Second reflector Surface are different in curvature.
`0015 The first and second reflector surfaces comprise
`Same parabolas, both parabolas are disposed So as to be
`different in position of focus.
`0016. The reflector Surface has a rectangular shape in
`plan View, and the reflector member comprises four reflector
`Surfaces divided by a pair of diagonal lines.
`0017. These and other objects and features of the present
`invention will become more apparent from the following
`detailed description with reference to the accompanying
`drawings.
`
`BRIEF DESCRIPTION OF DRAWINGS
`0018 FIG. 1 is a graph showing a parabola in an XZ
`plane of an XYZ orthogonal coordinate System;
`0019 FIG. 2 is a graph showing a parabola in a YZ-plane
`of the Orthogonal coordinate System;
`0020 FIG. 3 is a plan view of a light emitting diode
`device according to a first embodiment of the present
`invention as viewed from a Z direction;
`0021
`FIG. 4 is a sectional view of the device taken along
`an X-line;
`0022 FIG. 5 is a sectional view taken along a Y-line;
`0023
`FIG. 6 is a sectional view of a bundle of rays;
`FIG. 7 shows an XYZ orthogonal coordinate sys
`0024
`tem,
`0025 FIGS. 8 and 9 are graphs showing the positions of
`the focus P.
`0026 FIG. 10 is a plan view showing a reflector member
`in the Second embodiment of the present invention;
`0027 FIG. 11 is a perspective view of the reflector
`member;
`0028 FIG. 12 is a sectional view taken along the X-line
`of a light emitting diode device based on the reflector
`member of FIG. 10;
`0029 FIG. 13 is a sectional view of the device taken
`along the Y-line;
`0030 FIG. 14 is a graph showing a principle of the third
`embodiment of the present invention;
`0031 FIGS. 15 and 16 are sectional views of a light
`emitting diode device of the third embodiment;
`0032 FIG. 17 is a plan view of the fourth embodiment;
`0033 FIG. 18 is a sectional view taken along the X-line;
`0034 FIG. 19 is a sectional view taken along the Y-line;
`0035 FIG. 20 is a plan view of the fifth embodiment;
`0036 FIG. 21 is a sectional view taken along the X-line;
`0037 FIG.22 is a sectional view taken along a ridge line
`r
`
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`US 2003/0020077 A1
`
`Jan. 30, 2003
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`FIG. 23 is a sectional view taken along the Y-line;
`0.038
`0039 FIG. 24 is a sectional view of a bundle of rays;
`0040 FIG.25 is a sectional view of a light emitting diode
`device of the sixth embodiment of the present invention;
`0041
`FIG. 26 is a perspective view showing a conven
`tional light emitting diode device;
`0.042
`FIG. 27 is a sectional view of the light emitting
`diode device;
`0.043
`FIG. 28 is a perspective view showing another
`reflector; and
`0044 FIG. 29 is a sectional view of the reflector.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`004.5 The principle of the present invention will be
`described hereinafter.
`0.046
`FIG. 1 is a graph showing a parabola in an XZ
`plane of an XYZ orthogonal coordinate system, and FIG. 2
`is a graph showing a parabola in a YZ-plane of the orthogo
`nal coordinate System.
`0047 Referring to FIG. 1, the parabola S1 is expressed
`by the following equation of parabola
`
`0.048 where p1 is the focal distance from the origin PO
`to the focus P1.
`0049. Here, if the parabola S1 is a parabolic mirror, light
`beams emitted from a light source located at the focus P1 are
`changed by the parabolic mirror to light beams parallel with
`the Z-axis (optical axis) as shown by Solid lines. However,
`if the light source is located at a point Pm deflected from the
`focus P1 to the origin PO, the light beams from the light
`Source are changed to light beams receding from the Z-axis
`as shown by dotted lines, thereby expanding the bundle of
`rays in the XZ-plane.
`0050 Referring to FIG. 2, the parabola S2 is expressed
`by the following equation of parabola,
`
`0051 where p2 is the focal distance from the origin PO
`to the focus P2.
`0052) In the parabola Yi, the focal distance p2 is smaller
`than the focal distance p1 (p2<p1). Therefore, the curvature
`of the reflector (inverse number of radius of curvature) of the
`parabola S2 is larger than that of the parabola S1.
`0053 When the light beams emitted from the focus P2
`Strike the parabola S2, the light beams are changed to light
`beams parallel with the Z-axis as shown by solid lines.
`However, if the light source is located at a point Pm distant
`from the origin PO, the light beams from the light source are
`changed to light beams approaching the Z-axis as shown by
`dotted lines, thereby reducing the bundle of rays in the
`YZ-plane.
`0.054
`Consequently, if a reflector having the parabola S1
`in the XZ-plane and the parabola S2 in the YZ-plane is
`prepared, and a light Source is located at the point Pm
`between the focus P1 of the parabola S1 and the focus P2 of
`
`the parabola S2, the bundle of rays reflected from the
`reflector is wide in the XZ-plane and narrow in the YZ
`plane.
`0055. The present invention is based on the above
`described principle.
`0056 FIG. 3 is a plan view of a light emitting diode
`device according to a first embodiment of the present
`invention as viewed from the Z direction, FIG. 4 is a
`sectional view of the device taken along the X-line, FIG. 5
`is a Sectional view taken along the Y-line.
`0057 The light emitting diode device 10 comprises a
`Substrate 2 made of an epoxy resin, a cathode electrode
`pattern 3 and an anode electrode pattern 4 formed on the
`upper Surface of the Substrate 2. These patterns 3 and 4 are
`connected to underSide patterns through leads provided on
`side walls of the Substrate 2.
`0058 Alight emitting diode 1 is securely mounted on the
`Substrate 2. A reflector member 5 made of resin has an
`approximately Semispherical receSS and is mounted on the
`Substrate 2 Surrounding the light emitting diode 1. The
`reflector member 5 has a reflector Surface 5a formed on the
`inner Surface of the Semispherical receSS. The reflecting
`Surface 5a comprises a parabola S1 having a focus at a point
`P1, and a parabola S2 having a focus at a point P2. The light
`emitting diode 1 is located at a point between the points P1
`and P2. The parabolas S1 and S2 are cut at the upper surface
`of the substrate 2 to form an opening 5c as shown in FIG.
`5.
`0059. The reflector surface 5a is coated with a shine Ag
`plating. A cathode lead pattern 6 and an anode lead pattern
`7 are formed on outside walls and underside of the reflector
`member 5. The cathode and anode of the light emitting diode
`1 are connected to a terminal 6b of the cathode lead pattern
`6 and to a terminal 7b of the anode lead pattern 7 by bonding
`wires 8. The cathode lead pattern 6 and anode lead pattern
`7 are connected to the cathode and anode electrode patterns
`3, 4 at the undersides thereof.
`0060. The bonding wires 8 and the light emitting diode 1
`are Sealed by a Sealing member 9 made of a transmissive
`resin charged in the recess of the reflector member 5.
`0061. When an electric current is applied to the light
`emitting diode 1 through electrode patterns 3, 4, lead pat
`terns 6, 7 and bonding wires 8, the light emitting diode 1
`emits light. Light beams reflected by the reflector Surface 5a
`having the parabola S1 are expanded as shown in FIG. 4,
`and light beams reflected by the reflector Surface 5a having
`the parabola S2 are reduced as shown in FIG. 5. Thus, as
`shown in FIG. 6, the section 12 of the bundle of rays has an
`elongated ellipse.
`0062 Referring to FIG. 7, a line a is a cutting line for
`cutting the reflector member 5. The cutting line a is rotated
`180 degrees about the Z-axis in FIG. 3 in order to obtain a
`parabola in each Section.
`0063 FIG. 8 is a graph showing the positions of the
`focus P. The line A shows the change of the focus. For
`example, when 0=45, the focus P is at an intermediate
`position between the focus P1 and P2.
`0064 FIG. 10 is a plan view showing a reflector member
`in the Second embodiment of the present invention, and
`FIG. 11 is a perspective view of the reflector member.
`
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`US 2003/0020077 A1
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`Jan. 30, 2003
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`0065. The reflector member 15 comprises a first parabola
`area 15a1 having the parabola S1 and a Second parabola area
`15a2 having the parabola S2. In particular, the whole area of
`the first parabola area 15a1 is formed by the parabola S1,
`and the whole area of the second parabola area 15a2 is
`formed by the parabola S2.
`0.066 The first parabola area 15a1 is disposed about the
`X-axis and the Second parabola area 15a2 is disposed about
`the Y-axis.
`0067. The second parabola area 15a2 is located at a
`position near the Z-axis. Therefore, there is formed steps 16
`between both areas.
`0068 FIG. 12 is a sectional view taken along the X-line
`of a light emitting diode device based on the reflector
`member of FIG. 10, FIG. 13 is a sectional view of the
`device taken along the Y-line. The same parts as the device
`of FIGS. 4 and 5 are identified by the same reference
`numerals as FIGS. 4 and 5.
`0069. Positions of focuses P1 and P2 do not change as
`shown by a line B of FIG. 8.
`0070 FIG. 14 is a graph showing a principle of the third
`embodiment of the present invention. FIGS. 15 and 16 are
`Sectional views of a light emitting diode device of the third
`embodiment.
`0071. The light emitting diode device 30 has two parabo
`las S11 and S12 each of which has the same focal distance
`p1 as shown in FIG. 14. However, the parabola S12 is
`shifted from the X-axis distance d which is longer than the
`focal distance p1. The parabola S11 is provided on the
`X-axis and parabola S12 is disposed on the Y-axis. The light
`emitting diode 1 is located between the focus P1 of the
`parabola S11 and the origin P0 of the parabola S11. There
`fore, light beams discharge in the same directions as previ
`ous embodiments as shown in FIGS. 15, 16.
`0072 FIG. 17 is a plan view of the fourth embodiment,
`FIG. 18 is a sectional view taken along the X-line, and FIG.
`19 is a sectional view taken along the Y-line.
`0073. In a light emitting diode device 40, there is not
`provided the substrate 2 in FIG. 4 of the first embodiment.
`A reflector member 35 is downwardly extended and a
`reflector Surface 35a has a flat bottom 35c. The light
`emitting diode is mounted on the bottom 35c. Other parts are
`the same as the first embodiment.
`0074 FIG. 20 is a plan view of the fifth embodiment.
`FIG. 21 is a sectional view taken along the X-line, FIG.22
`is a Sectional view taken along a ridge line r, and FIG. 23 is
`a Sectional view taken along the Y-line.
`0075) A light emitting diode device 50 has a reflector
`member 45 having a construction similar to the reflector
`member 35 of the fourth embodiment. The reflector member
`45 has a rectangular shape elongated in the X-axis in plan
`view, and comprises four reflector surfaces 45a, 45b, 45c
`and 45d. The reflector Surfaces 45a and 45c are formed by
`the parabola S1, and reflector Surfaces 45b and 45d are
`formed by the parabola S2. Between adjacent reflector
`Surfaces the ridge line r is forms. Opposite ridge lines r
`formed a parabola s3.
`0076 FIG. 9 shows the position of the focuses P of the
`parabolas S1, S2 and S3. When the angle 0 of the line a
`
`(FIG. 7) is zero (0=0), the focus position is P1 at a position
`C1 on a line C. AS the angle 0 increases, the position P
`becomes high. At a position C3 (0=about 30), the position
`P is a maximum P3 of the parabola S3. The parabola S3 is
`gentle compared with the slope of the parabola S1 as shown
`in FIG. 22.
`0077. When the angle 0 further increases, the position P
`becomes low. At a point C2, the position P becomes low
`ermost of the parabola S2 at focus P2.
`0078. In the present embodiment, there is provided a
`region Ch (FIG. 9) where the focal distance p becomes
`larger (P3) than the focal distance p1. Therefore, light beams
`are further expanded from the Z-axis as shown in FIG. 22.
`Thus, the Sectional shape of the bundle of rays expands to a
`rectangular shape elongated in the X-line as shown in FIG.
`24. Consequently, a large rectangular area is uniformly
`illuminated.
`007.9 FIG.25 is a sectional view of a light emitting diode
`device of the sixth embodiment of the present invention.
`0080. In the light emitting diode device 60, the bonding
`wire 8 for the cathode and the cathode leading pattern 6 in
`the first embodiment are omitted. The cathode of the light
`emitting diode 1 is directly connected to the cathode elec
`trode pattern 3 by die bonding. Other construction is the
`Same as the first embodiment.
`0081. While the invention has been described in conjunc
`tion with preferred specific embodiment thereof, it will be
`understood that this description is intended to illustrate and
`not limit the scope of the invention, which is defined by the
`following claims.
`
`What is claimed is:
`1. A light emitting diode device comprising:
`a reflector member having an approximately Semispheri
`cal receSS,
`a reflector Surface provided on an inner Surface of the
`receSS,
`a light emitting diode provided in the recess, and
`the light emitting diode being located at a position So that
`a part of light beams emitted from the light emitting
`diode recedes from an optical axis, and another part of
`the light beams approaches to the optical axis.
`2. The device according to claim 1 further comprising a
`Substrate, and the reflector member being mounted on the
`Substrate.
`3. The device according to claim 1 wherein the reflector
`Surface includes a first reflector Surface about an X-axis and
`a Second reflector Surface about a Y-axis.
`4. The device according to claim 3 wherein each of the
`first and Second reflector Surfaces includes at least one
`parabola.
`5. The device according to claim 4 wherein the light
`emitting diode is located at a position between a focus of a
`parabola about the X-axis and a focus of a parabola about the
`Y-axis.
`
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`US 2003/0020077 A1
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`Jan. 30, 2003
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`6. The device according to claim 4 wherein the first
`reflector Surface and the Second reflector Surface are differ
`ent in curvature.
`7. The device according to claim 4 wherein the whole area
`of the first reflector Surface is formed by a first parabola, and
`the whole area of the second reflector surface is formed by
`a Second parabola.
`8. The device according to claim 4 wherein the first and
`Second reflector Surfaces are formed by Same parabolas, both
`parabolas are disposed So as to be different in position of
`focus.
`
`9. The device according to claim 4 wherein the reflector
`Surface has a rectangular shape in plan view.
`10. The device according to claim 5 wherein a focal
`distance of the parabola about the X-axis is longer than a
`focal distance of the parabola about the Y-axis.
`11. The device according to claim 9 wherein the reflector
`member comprises four reflector Surfaces divided by a pair
`of diagonal lines.
`
`Nichia Exhibit 1009
`Page 18
`
`