JP2014003168A - Lens, luminaire, photoreceiver, and optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens, which collects light from a light emitter and outputs it, capable of enhancing narrow directivity while avoiding loss caused by total reflection at an interface.SOLUTION: A catadioptric interface 1 is arranged to a periphery of a curved surface portion of a lens 6, and a lateral reflection face 2 is installed outside the interface. Light incident on the catadioptric interface 1 from a light source at an angle equal to or more than the critical angle is totally reflected laterally, is incident on the lateral reflection face 2, and is reflected and emitted forward. The catadioptric interface 1 can be configured in a conical face by installing a toroidal face 5 between the catadioptric interface 1 and the optical center. Light whose radiation angle from the light source is within a range exceeding about 50° is reflected at an indirect reflection face 4, is incident on the catadioptric interface 1 within the critical angle, and is emitted forward.

Description

  The present invention relates to a lens that forms an interface in a substantially normal direction of the optical axis from the side surface of the lens, converts the total reflected light from the interface into the optical axis direction, and emits refracted light from the interface, and illumination using the lens The present invention relates to a device, a light receiving device, and an optical device.

Light emitting diodes (LEDs) include a lead frame type LED in which a light emitting element is provided in a cup of a metal lead frame and resin molded, and a surface mount type in which the light emitting element is resin molded on a substrate. Since many lead frame type LEDs have a spherical lens formed at the tip of a cylinder, they are also called bullet type LEDs. Since the focal length is more than about three times the radius of the spherical lens, the cylindrical portion connected to the hemispherical surface has a long lens shape. As shown in FIG. 11, the spherical lens has large ambient light aberrations and large dimensions. Therefore, many of the conventional examples of Patent Document 1 and Patent Document 2 are provided with a light emitting element at a position about 2 to 2.5 times the radius of curvature. , Provided on the tip side from the focal position.
The light intensity half-value angle of the surface-mounted LED having a flat resin-sealed surface is about 120 °. The illuminating device has many uses in which the half-value angle is narrower than this, and Patent Document 3 shows a lens as shown in FIG. 12 in which a light emitting element is provided at a position about twice the radius of curvature. When the light emitting element is provided at a position about twice the radius of curvature, the emission angle is about 15 °, and the LED is used for applications such as a light intensity half-value angle of 30 °. Patent Document 1 discloses an elliptic lens LED that emits outward around the lens surface by defining the distance between the light emitting element and the tip of the elliptic lens surface.

Since the surface-mounted LED with a lens has a shape in which a spherical lens protrudes greatly on the tip side, a light emitting device provided with a Fresnel lens for the purpose of reducing the height is disclosed in Patent Document 4. Patent Document 4 proposes a light emitting device in which a phosphor is dispersed in a transparent material to cover a light emitting element and a Fresnel lens is formed on the light emitting element.

When a surface-mounted LED with a half-value angle of about 120 ° is used in an illumination device, the external lens has a condensing angle of about 40 ° or less, so a concave mirror must be used. However, a hemispherical lens that acts like a concave mirror Is disclosed in Patent Document 5. Patent Document 5 is a light-emitting device in which an exit surface is a flat surface of a hemispherical lens and a concave incident surface for LED installation is formed on the top of the hemispherical surface. The emitted light from the light source goes straight through the concave incident surface and diffuses inside the hemispherical lens, and is totally reflected at the peripheral side of the hemispherical lens due to an incident angle larger than the critical angle, and exits from the flat exit surface. . Since the diffused light from the light source is also emitted from the flat emission surface, the light reflected by the concave surface and the diffused light from the light source are mixed. Since the external light incident from the radiation surface side is smaller than the critical angle near the top of the lens, the external light is transmitted rearward to prevent pseudo lighting.

In Patent Document 6, a convex incident surface facing the LED element is formed on a part of the concave incident surface of Patent Document 5, and light directed from the light emitting element toward the lens exit surface is condensed. The light to other than the convex incident surface is the same as in Patent Document 5. This is a proposal of a signal lamp that controls light distribution by arranging a plurality of minute lenses on the exit surface because a large amount of light is concentrated on the convex surface on the front surface of the light emitting element and the non-uniformity of the light flux increases. In Patent Document 7, the hemispherical surface of the lens side surface and the concave incident surface of Patent Document 6 are diffused to mix excitation light and fluorescence at the center of the lens to reduce uneven color of excitation light and fluorescence of the fluorescence conversion white LED. It is an object.

Japanese Patent Laid-Open No. 11-46013 JP 2008-258530 A Japanese Patent No. 3995906 JP 2007-88093 A Japanese Patent No. 2952127 JP 2006-48165 A Japanese Patent No. 4635774

Paraxial rays from the light-emitting element embedded in the focal point f2 inside the spherical lens become almost parallel light, but the ambient light has large spherical aberration as shown in FIG. The focal length f2 inside the spherical lens needs to be 3.5 times the spherical radius of curvature r of silicone resin with a refractive index of 1.4, and 3.1 times the spherical radius of curvature r of epoxy resin with a refractive index of 1.47. Therefore, it has a structure in which a cylindrical surface is connected to a spherical lens. Since the aberrations of the ambient light are large and the dimensions are long, many of them are shortened by about 2 to 2.5 times the radius of curvature to reduce the spherical aberration of the ambient light. Even at about 2.5 times, the top of the lens protrudes and the upper dimension of the light emitting element is long, making it difficult to reduce the size or height.

The LED with a narrow directivity angle has a long cylindrical part of the lens. Therefore, light incident from the light emitting element near the boundary between the spherical surface and the cylindrical surface is totally reflected and condensed near the top of the spherical lens, but refracted near the top. There are light emitted in the side surface direction and light that is totally reflected near the top and returns to the light emitting element side. Such a trace of the totally reflected light is shown in FIG. 11, but is also shown in FIG. When the light is totally reflected in the vicinity of the top of the spherical lens and returns to the light emitting element side, multiple reflection occurs and most of the internal loss occurs. Since the conventional elliptic lens is close to the critical angle at the outer peripheral portion of the ellipsoid, if it exceeds this, total reflection occurs, and leakage in the side surface direction and light returning to the light emitting element side increase.

If the light emitting element is provided at a position about twice the radius of curvature, the light incident near the boundary between the spherical surface and the cylindrical surface can avoid the total reflection because the incident angle is within the critical angle, but the emission angle increases. Patent Document 1 is proposed based on a simulation result in which an internal loss that returns to the light emitting element side by total reflection at the top portion by an elliptic lens is avoided. An elliptic lens having the same optical path length between the ambient light and the optical axis light can be emitted as parallel light as shown in FIG. 4 of the present application, and is therefore suitable for applications with a narrow directivity angle. Near 9 °, beyond this, total reflection occurs. For this reason, the simulation result emitted outside in the vicinity of the lens surface of Patent Document 1 is not the effect of the ellipsoidal curve but the effect of the position of the light emitting element. Thus, it is difficult for a conventional elliptical lens to achieve a narrow directivity while avoiding total reflection, and there is a trade-off between avoiding total reflection and realizing a narrow directivity.

In Patent Document 4, the numerical aperture is very large because the Fresnel lens can be reduced in height, but the Fresnel lens can only reduce the lens thickness itself. As shown in FIG. 1 of Patent Document 4, when the numerical aperture is increased to 0.94, the peripheral portion of the Fresnel lens is obliquely incident on a slight refractive surface facing the light source, and only a small surface is involved in the emission. Furthermore, the light flux density is low in inverse proportion to the square of the distance from the light source. The vicinity of the optical axis is close to the light source, so the light flux density is high, and since there are few shaded surfaces with Fresnel irregularities, the excitation light is concentrated near the optical axis and the unevenness of the light flux is large. Only the light from the phosphor in the vicinity of the light emitting element performs a light collecting action equivalent to that of the excitation light, and the light from other phosphors is an oblique ray with respect to the lens, so the half-value angle is very large. As shown in FIG. 13, depending on the incident angle of light from the phosphor, the Fresnel lens surface is totally reflected to the phosphor side to cause internal loss. Since the phosphor layer spreads as much as the lens width, the ratio of internal loss due to total reflection increases. In the vicinity of the optical axis of the fluorescence conversion LED, the blueness of the excitation light is strong, and since the optical path length in the phosphor layer is longer toward the peripheral side, the fluorescent light such as yellow is strong at the peripheral side. Due to the oblique light from the phosphor, the directivity angle of fluorescence alone is very large and the profile is extremely low, so that the color unevenness becomes remarkable.

Patent Document 5 describes that “radiate in a desired angle range”. However, when diffused light from a light source is refracted on a plane emission surface, the light diffuses in a direction along the plane as shown in FIG. 14 within a critical angle. . When the diffused light from the light source exceeds the critical angle, it is totally reflected on the plane emission surface and retroreflected to the light source side. Reflection at the periphery of the spherical reflecting surface is also retroreflected to the light source side through the reverse path. The light emitted in the hemispherical direction is multiple-reflected along the hemispherical surface as shown in FIG. 14, and is emitted from the peripheral portion in the optical axis direction. For this reason, only the central part and the peripheral part of the lens are emitted in the direction of the optical axis, and the others are a wide range of diffused light. As described above, it is difficult to radiate by controlling the hemispherical lens arbitrarily within a desired angle range.

In Patent Document 6, a convex surface is formed in the LED installation concave portion in Patent Document 5 so as to face the LED element, and a large amount of light is collected on the convex surface in front of the light emitting element, and concentrated in a narrow emission range as shown in FIG. Non-uniformity increases. The light radiated in the hemispherical direction is multiple-reflected along the hemispherical surface and emitted from the peripheral part in the optical axis direction, so that only the central part and the peripheral part of the lens are emitted in the optical axis direction as in Patent Document 5. For this reason, in order to alleviate the non-uniformity of the luminous flux, many microlenses are arranged and diffused on the exit surface, but it is difficult to improve the luminance unevenness of the display surface.

In Patent Document 7, diffusion processing is performed on the hemispherical reflecting surface and the concave incident surface instead of the microlens on the exit surface in Patent Document 6, and unevenness of the luminous flux is simultaneously reduced by reducing the uneven color of the excitation light and the fluorescence by the diffusion processing. It is a proposal to improve. However, when the concave and convex diffusion process is performed on the reflecting surface of the hemispheric surface, as shown in FIG. 16, the light that is diffused and then totally reflected by the plane exit surface and returns to the light source side, the light that is transmitted through another hemispherical surface, There is light that is refracted and transmitted through the surface, resulting in light loss. When diffusion treatment is performed on the concave incident surface, there is light that returns to the light source side after being totally reflected at the peripheral portion of the flat emission surface. If there are irregularities as shown in FIG. 2 of Patent Document 7, the lens cannot be removed from the mold. Diffusion treatment of the concave entrance surface with white paint is diffused and then totally reflected on the plane exit surface and returned to the light source side, light transmitted through another hemisphere, light refracted / transmitted on the uneven surface, and light loss due to reflectance There is. The white paint has contradictory characteristics such that the concave incident surface has a transmittance of 70% or more, and the hemispherical reflective surface has a reflectance of 90% or more. When the excitation light is emitted from the center of the lens in the vertical direction on the convex surface of the concave entrance surface, and the fluorescence is reflected on the center of the lens by the reflection surface of the hemispherical surface, it is refracted sideways along the emission surface as shown in FIG. Since the light is reflected, color unevenness cannot be reduced.

光軸の法線方向側に突き出した界面は後述するように屈折面としても兼用するので反射屈折界面１と呼び、ＬＥＤのレンズは球面レンズあるいは楕円レンズが光軸周辺に形成されているので光軸レンズ６と呼ぶことにする。ＬＥＤレンズの光軸から曲面辺縁までは光軸レンズ６の曲面で、曲面辺縁の外側に接して反射屈折界面１を設けている。曲率半径の２〜２．５倍程度の位置に発光素子を設けた光軸レンズ６の集光角は約３０〜４０°である。反射屈折界面１とレンズの境界における発光素子からの放射角θが３３°のとき、屈折率１．４７のエポキシ樹脂の場合、臨界角は４２．９°のため境界における傾斜角ωは数１により８０．１°以下の必要がある。このため界面は光軸レンズ６との境界部では漏斗状に窪み、光軸レンズ６との境界線は環状のＶ字溝である。臨界角余裕をとり約１６°を差し引いて図１では境界部の傾斜角ωは６４°である。図１は反射屈折界面１が楕円１eの場合を実線、放物線１pを破線で示し、反射屈折界面１が放物線の場合は平行光を射出可能だが光学系が非常に大きくなる。反射屈折界面１を回転楕円体にすると発光素子からの放射角θによる反射光が楕円の焦点近傍に収束するので光学系を小型化可能である。図１の楕円の離心率ｅは０．８３である。 The vicinity of the boundary between the curved surface of the LED lens and the cylindrical portion is a region where the incident angle is greater than the critical angle and total reflection occurs near the top of the lens. The interface where the incident angle from the light emitting element is greater than or equal to the critical angle may also exist in the normal direction of the optical axis. When the front of the low refractive index material n1 such as air and the rear of the high refractive index material n2 of the translucent material protrudes from the vicinity of the boundary between the lens cylindrical portion and the spherical surface toward the normal direction side of the optical axis as shown in FIG. An interface is realized. Assuming that the radiation angle of the light emitting element is θ, the angle between the interface and the optical axis is ω, and the critical angle is θc, these are expressed by Equation 1, and the critical angle θc is expressed by Equation 2.

The interface protruding to the normal direction side of the optical axis is also referred to as a catadioptric interface 1 because it also serves as a refracting surface, as will be described later, and the LED lens is a spherical lens or an elliptical lens formed around the optical axis. It will be called the axial lens 6. From the optical axis of the LED lens to the curved edge, the curved surface of the optical axis lens 6 is provided, and the catadioptric interface 1 is provided in contact with the outside of the curved edge. The condensing angle of the optical axis lens 6 provided with the light emitting element at a position of about 2 to 2.5 times the radius of curvature is about 30 to 40 °. When the radiation angle θ from the light emitting element at the boundary between the catadioptric interface 1 and the lens is 33 °, the epoxy resin having a refractive index of 1.47 has a critical angle of 42.9 °, and the inclination angle ω at the boundary is expressed by the following equation (1). Needs to be 80.1 ° or less. Therefore, the interface is funnel-shaped at the boundary with the optical axis lens 6, and the boundary with the optical axis lens 6 is an annular V-shaped groove. Taking the critical angle margin and subtracting about 16 °, the inclination angle ω at the boundary is 64 ° in FIG. FIG. 1 shows the case where the catadioptric interface 1 is an ellipse 1e as a solid line and the parabola 1p as a dashed line. When the catadioptric interface 1 is a parabola, parallel light can be emitted, but the optical system becomes very large. If the catadioptric interface 1 is a spheroid, the reflected light from the light emitting element due to the radiation angle θ converges in the vicinity of the focal point of the ellipse, so that the optical system can be miniaturized. The eccentricity e of the ellipse in FIG. 1 is 0.83.

When the catadioptric interface 1 is composed of an ellipsoid rotating around the optical axis, a paraboloid, etc., it is a toroidal surface. A structure in which the toroidal surface is moved to the incident surface side and the catadioptric interface 1 is a conical surface will be described later. Since this toroidal surface is a part of an ellipse in a cross-sectional view, it is approximated by a curvature circle, and C1 is the center of the curvature circle. A curvature circle is a circle in contact with three adjacent points on the curve. The curve can be approximated by a plurality of curvature circles instead of one curvature circle. The toroidal surface is an annular surface formed with another axis that does not pass through the center of the arc as a rotation axis, and is used as a lens such as an astigmatism correction lens. Also become. FIG. 2 is a cross-sectional view in which four toroidal surfaces are configured by a circle of curvature. Although the centers of curvature circles C1, C2, and C3 are shown, C4 is out of the drawing because of its large curvature radius. In FIG. 2, the inclination angle ω at the boundary of the catadioptric interface 1 is 65 °, and the radius of curvature is 20% longer than in the case of FIG.

円は数４で示され、これらの交点は数５で求められる。

円の数４の代わりに直接に楕円、双曲線、放物線などの式を用いても交点を求めることが出来る。
これを用いて放射角θの交点座標とその接線を求めると数６で示され、傾斜角ωを数７で求めることが出来る。

例えば放射角θ＝４０°の交点座標はｘ＝１．４０，ｙ＝１．６６である。交点座標の接線方程式から交点の傾斜角ωは７５．４°である。 The inclination angle ω on the catadioptric interface 1 will be described with reference to FIG. The position of the light emitting element is the origin, the coordinates of the center C1 of the circle are (m, n), and the radius r. When the x-coordinate of the boundary point between the optical axis lens 6 and the catadioptric interface 1 is 1, and the circle in FIG. 2 is represented by this ratio, a straight line having a radiation angle θ incident on the boundary of 33 ° is expressed by the equation (3). The y coordinate c of the point is 1.54.

A circle is represented by Equation 4, and these intersection points are obtained by Equation 5.

Instead of the number of circles 4, the intersection point can also be obtained directly using an equation such as an ellipse, a hyperbola, or a parabola.
Using this, the coordinates of the intersection of the radiation angle θ and its tangent are obtained as shown in Equation 6 and the inclination angle ω can be obtained as Equation 7.

For example, the intersection coordinates of the radiation angle θ = 40 ° are x = 1.40 and y = 1.66. From the tangent equation of the intersection coordinates, the inclination angle ω of the intersection is 75.4 °.

In the conventional lens, when light from the light emitting element is incident on the cylindrical surface, the light is totally reflected and condensed near the top of the spherical lens, but FIG. 2 has a catadioptric interface 1 instead of the cylindrical surface, and is incident from the light emitting element. Light enters at a critical angle or more and is totally reflected laterally. The angle β formed by the reflection direction and the optical axis is expressed by Equation 8 using the incident angle α and the above ω and θ.

In FIG. 2, the radiation angle θ of the light emitted from the light emitting element is incident on the catadioptric interface 1 in the range of about 33 ° to 47 °, but is different in the region where the radiation angle θ of the light emitting element exceeds about 50 °. It is incident on the reflective surface of. The reflection surface that reflects light diffusing from the light emitting element in the direction of the side surface having an emission angle θ of about 50 ° or more in the direction of the catadioptric interface 1 will be referred to as an indirect reflection surface 4. When the light is emitted from the side surface and reflected by the indirect reflection surface 4, it falls within the critical angle to the catadioptric interface 1 and is refracted and emitted forward. As described above, the catadioptric interface 1 is used as both a reflecting surface and a refracting surface. However, the reason why the catadioptric surface 1 also serves as a refracting surface is indirect light because the position of the indirect reflecting surface 4 is on the normal direction side of the catadioptric interface 1 and catadioptric. This is because refraction occurs when the incident angle ε to the interface 1 is within a critical angle. The catadioptric interface 1 is reflected by the side reflecting surface 2 and exits from the refractive exit surface 3 in the optical axis direction. Instead, the reflected light of the indirect reflecting surface 4 is refracted by the catadioptric interface 1 to the optical axis direction. It is a structure to inject. As described above, the catadioptric interface 1 has both a function of totally reflecting the diverging light from the light emitting element to the side and a function of refracting and transmitting the reflected light from the indirect reflection surface 4 in the optical axis direction.

反射屈折界面１の光軸レンズとの境界に入射角εで入射して、反射屈折界面１の傾斜ωにより光軸方向となす角γで射出するとき数１０で表される。

When the catadioptric interface 1 is a convex refractive toroidal surface, the reflected light of the indirect reflecting surface 4 is slightly diffused light than the parallel light in order to be refracted and converted into parallel light. The definition of the concave surface and the convex surface is for the target light, and acts as a concave surface when the catadioptric interface 1 reflects sideways, and acts as a convex surface when refracted and emitted. The LED often uses a phosphor, and the light emitting element and the phosphor are collectively referred to as a light source. The indirect reflection surface 4 converts the diffused light from the light emitting element 9 closer to parallel light in a cross-sectional view and converts it by tilting toward the optical axis side. Therefore, the indirect reflecting surface 4 is a parabolic surface, a conical surface, or an intermediate curve between the parabolic surface and the conical surface, and is a toroidal surface whose rotational axis is inclined inward from the y axis of the parabola. When the light emitted from the catadioptric interface 1 is diffused light, it may be wider or narrower than the diffusion angle of the indirect reflecting surface 4 described above. The wide indirect reflecting surface 4 is close to a conical surface, and vice versa when it is narrow. Assuming that the angle formed by the indirect reflection surface 4 with the optical axis is η, the angle ρ formed by the reflected light of the light having the radiation angle θ from the light source with the optical axis is expressed by Equation 9.

When the light enters the boundary of the catadioptric interface 1 with the optical axis lens at an incident angle ε and exits at an angle γ formed with the optical axis direction by the inclination ω of the catadioptric interface 1, it is expressed by Equation 10.

図３の入射トロイダル面５は発光素子９に対面して環状に周回している。円弧だけでなく、楕円、放物線、双曲線など集光作用のある凸面であれば環状の入射トロイダル面５を形成出来る。ここで、光学中心とは発光素子、受光素子、ビームウェスト位置などを表し、平行光に変換する場合は焦点に一致するが、拡散光に変換する場合は後述するように焦点からずれた位置である。入射トロイダル面５を使用して反射屈折界面１から平行光を射出する場合の間接反射面４は放物線のｙ軸より内側に回転軸を傾斜したトロイダル面である。 The toroidal surface of the concave reflection surface of the catadioptric interface 1 can be moved to the entrance surface of the lens to make the catadioptric interface 1 a conical surface. When the toroidal surface of the incident surface is referred to as the incident toroidal surface 5, the incident toroidal surface 5 can be converted into parallel in a cross-sectional view, so that the catadioptric interface 1 becomes a conical surface and it is easy to make the emitted light parallel to the optical axis. Become. Since the inclination angle ω and the side reflection surface 2 formed by the conical surface as the optical axis need only satisfy the critical angle condition of Equation 1, it can be set more easily than Equation 7. The incident toroidal surface 5 is configured as follows. A convex arc having a radius of curvature r is formed at the interface with a material having a lower refractive index n1, which is a light-transmitting material having a refractive index n2, and is refracted by the convex surface from the focal point on the low refractive index n1 side to be substantially parallel to the light transmitting material. When light propagates, the focal length f1 on the low refractive index n1 side and the focal length f2 on the high refractive index n2 side are expressed by Equation 11 for paraxial rays.

The incident toroidal surface 5 of FIG. 3 faces the light emitting element 9 and circulates in an annular shape. An annular incident toroidal surface 5 can be formed as long as it is not only an arc but also a convex surface having a condensing function such as an ellipse, a parabola, or a hyperbola. Here, the optical center represents a light emitting element, a light receiving element, a beam waist position, and the like. When converted to parallel light, it coincides with the focal point, but when converted to diffused light, it is deviated from the focal point as described later. is there. The indirect reflection surface 4 in the case where parallel light is emitted from the catadioptric interface 1 using the incident toroidal surface 5 is a toroidal surface whose rotational axis is inclined inward from the y-axis of the parabola.

反射屈折界面１は凹面のトロイダル面なので放射角θが増大するに従って反射方向が時計方向に回転して後方になり、反射屈折界面１の反射光は断面視で収束光である。図２では反射屈折界面１の反射光は３０°の収束光だが側方反射面２の凸面によって１８°に縮小している。 A reflection surface that reflects the light reflected in the side surface direction by the catadioptric interface 1 is referred to as a side reflection surface 2, and the side reflection surface 2 reflects light traveling in the outer peripheral direction obliquely forward. The angle χ formed by the side reflection surface 2 with the optical axis is obtained from a tangent equation. When the angle formed by the reflected light from the side reflection surface 2 with the optical axis is δ, these relationships are expressed by Equation 12.

Since the catadioptric interface 1 is a concave toroidal surface, the reflection direction rotates clockwise as the radiation angle θ increases, and the reflected light of the catadioptric interface 1 is convergent light in a cross-sectional view. In FIG. 2, the reflected light of the catadioptric interface 1 is 30 ° convergent light but is reduced to 18 ° by the convex surface of the side reflecting surface 2.

When the center of curvature of the catadioptric interface 1 is brought closer to the origin, the reflection angle β increases and the inclination angle χ of the side reflection surface 2 rotates in the clockwise direction. FIG. 8 shows an example in which the reflected light is easily converted into the optical axis direction when the reflected light is reflected by a steeply inclined conical surface rather than directly incident on the refractive exit surface 3. Although there are two side reflecting surfaces 2, increasing the total reflecting surface by one does not affect the efficiency, so the side reflecting surface 2 of the second cone is made parallel to the optical axis from the refractive exit surface 3. Dedicated to the matching function. The side reflecting surface 2 in FIG. 8 is closer to the origin side than the center C2 of the side reflecting surface 2 in FIG. Conversion to parallel light is possible by providing the convex side reflection surface 2 with a focal length that is approximately half the condensing distance by the concave catadioptric interface 1. When the reflected light of the side reflecting surface 2 is traced using Equation 12, substantially parallel light is incident on the side reflecting surface 2 of the second cone. Compared with the example in which the incident toroidal surface 5 converts the light into parallel light as shown in FIGS. 3 and 4, the incident surface can be made flat as shown in FIG. 8, and the lens 7 is covered immediately after the sealing resin is injected. There are good features.

図３の構造では屈折射出面３への入射光が断面視で平行光になるが、図２の構造では図８の例を除き拡散光になる。射出光を平行光にする場合は側方反射面２の反射光は断面視で平行よりもやや開いた拡散光を平行光に戻すので図２の屈折射出面３は凸面のトロイダル面である。図２では反射屈折界面１の反射光は３０°の収束光だが側方反射面２の凸面によって１８°に縮小している。光度半値角がこれより広ければ屈折射出面３は円錐面、凹面も可能である。 The refractive exit surface 3 emits light reflected obliquely forward from the side reflection surface 2 from the transparent material into the air. The angle ζ formed by the refracting exit surface 3 when it is emitted in the optical axis direction is an angle δ formed by the reflected light direction and the rotational axis, and Equation 13 is derived from Snell's law. In the case of air, n1 is omitted and n1 is omitted.

In the structure of FIG. 3, incident light on the refractive exit surface 3 becomes parallel light in a sectional view, but in the structure of FIG. 2, it becomes diffuse light except for the example of FIG. When the emitted light is converted into parallel light, the reflected light from the side reflecting surface 2 returns the diffused light that is slightly more open than parallel in a sectional view to parallel light, so that the refractive exit surface 3 in FIG. 2 is a convex toroidal surface. In FIG. 2, the reflected light of the catadioptric interface 1 is 30 ° convergent light but is reduced to 18 ° by the convex surface of the side reflecting surface 2. If the half-value angle is wider than this, the refractive exit surface 3 can be a conical surface or a concave surface.

３００μｍ角の発光素子９はｄが０．１５ｍｍなので、ｆ＝７．８ｍｍ、ｎ２＝１．４７のときの拡散角度φは１．１°である。蛍光変換白色ＬＥＤの場合は蛍光体層の寸法ｄが発光素子より大きく、拡散角度φが大きくなる。例えば、砲弾型ＬＥＤのカップ寸法を半径が約０．５ｍｍとすると蛍光体層の寸法ｄ＝０．５ｍｍ、焦点距離ｆ＝７．８ｍｍ、ｎ２＝１．４７のとき拡散角度φは３．７°である。 The light-emitting element 9 uses a chip of about 300 μm square, and the direction of refraction by the optical axis lens 6 differs between the center light and the peripheral light of the chip, resulting in a parallel error. When the dimensional difference between the center and the periphery of the light emitting element 9 is d and the focal length is f, the diffusion angle φ is expressed by the following equation (14).

Since the light emitting element 9 of 300 μm square has d of 0.15 mm, the diffusion angle φ when f = 7.8 mm and n2 = 1.47 is 1.1 °. In the case of a fluorescent conversion white LED, the dimension d of the phosphor layer is larger than that of the light emitting element, and the diffusion angle φ is large. For example, if the cup-type LED has a radius of about 0.5 mm, the diffusion angle φ is 3.7 when the phosphor layer dimension d = 0.5 mm, the focal length f = 7.8 mm, and n2 = 1.47. °.

Since the light emitting element 9 is inside the optical axis lens 6, the focal length f2 is expressed by Equation 11, and the paraxial ray is refracted by the spherical surface and converted into parallel light. Deviation from parallel light due to approximate spherical aberration. Even if the light emitting element is shifted from the focal point, diffused light is generated. Assuming that a point where a light beam incident on the lens aperture from the periphery of the light emitting element 9 in FIG. Even if the light emitting element is provided at the position F and the radius of curvature r of the lens is f / g times, the same diffusion angle φ is obtained. When the radius of curvature is f / g times the number 7, it becomes diffuse light.

等光路長の原理と楕円の長軸ａ、短軸ｂの係数を結びつける直接的な関数がないので反復計算あるいはスネル則に基づいた光線追跡が必要である。これらの方法により屈折率１．４７のエポキシ樹脂ではほぼａ＝４、ｂ＝３、 ｅ＝０．６６である。屈折率が異なる物質ではスネル則に基づいた光線追跡あるいは軸光と周辺光の光路長が等しくなる楕円面形状にするとほぼ平行光を射出することが出来る。楕円レンズ単独の集光角は約３０°である。 Since the spherical lens has spherical aberration, the optical axis lens 6 in FIGS. 3, 4 and 8 uses an elliptical lens, and an elliptical lens in which the optical path lengths of the ambient light and the optical axis light are equal can be emitted as parallel light. It is. The ellipsoidal surface is expressed by the following formula (15). When the major axis is x, the light emitting element is provided at a position a · e on the far side of the eccentricity e from the emission surface.

Since there is no direct function that links the principle of the equal optical path length and the coefficients of the major axis a and the minor axis b of the ellipse, ray tracing based on iterative calculation or Snell's law is necessary. With these methods, the epoxy resin having a refractive index of 1.47 has a = 4, b = 3, and e = 0.66. For substances having different refractive indexes, parallel light can be emitted by tracing light based on Snell's law or by using an ellipsoidal shape in which the optical path lengths of axial light and ambient light are equal. The condensing angle of the elliptic lens alone is about 30 °.

An LED having a flat phosphor layer is subject to color separation depending on the direction because the length of the phosphor layer varies depending on the direction of the inclined light. If the phosphor layer is formed in a hemisphere, it can be prevented, but the manufacture becomes difficult. For this reason, conventionally, there are many proposals for mixing excitation light and fluorescence by diffusion, but it is difficult to achieve a narrow directivity and sufficient color mixing.
In FIG. 7, even if the phosphor layer is flat, if the directivity angles of the optical axis lens and the catadioptric interface 1 are made to coincide with each other, the color mixture can be prevented because additive averaging is performed. A mechanism that is averaged by additive color mixture when excitation light and fluorescence are emitted in the same direction will be described. The light emitted from the optical axis lens 6 is bluish white in which excitation light is dominant, but the reflected light from the indirect reflection surface 4 is yellowish white because fluorescence is dominant. The left side of the optical axis lens 6 in FIG. 7 diffuses blue-white light where excitation light is dominant on the left side, but diffuses yellowish white light to the left side from the catadioptric interface 1 on the right side of the optical axis to If the directivity angle is approximately matched, the directivity angle range is additively mixed and recognized as a complementary white color. When the three light beams emitted from the optical axis lens 6 and the three light beams reflected from the indirect reflection surface 4 are compared, the inclinations are substantially the same. The right direction of the optical axis is also averaged for the same reason. Since light having an emission angle of about 30 to 50 ° is a region where excitation light and fluorescence are balanced, white light of a complementary color is emitted from the refractive exit surface 3. By averaging, it is possible to illuminate the light with a half-value angle of 30 ° without color separation.

The ratio from the light source to the lens tip with respect to the lens radius is about 3 times that of the lens of FIG. 11, and the ratio of the conventional elliptic lens is about 2.5 times, but it is formed by the catadioptric interface 1, the side reflecting surface 2, and the like. The ratio of the lens 7 is reduced to about 1 to 1.2. Further, there is an advantage that there is no total reflection loss and side leakage light. The lens of FIG. 12 avoids total reflection under the condition that the ratio from the light source to the lens tip with respect to the lens radius is about twice and the half-value angle is 15 ° or more, but the present lens is about 1 to 1.2 times. Can be made thinner. The radiation angle is not limited as described above and emits parallel light. As shown in FIG. 6 and the example of 30 ° can be set independently as shown in FIG.

If a light receiving element such as a photodiode or a phototransistor is provided at the optical center with the light traveling direction opposite to that of the LED, light can be condensed with high efficiency according to the setting of the directivity angle. For example, in human body detection using an infrared sensor, disturbance infrared rays are detected when the directivity angle is too wide as shown in FIG. 12, but the design can be made in accordance with the requirement of the directivity angle. The lens 7 can be used not only in combination as a single lens as shown in FIG. 3, but also as a component in which the light emitting element 9 is housed in a case. Since the lens has a low profile, a photo interrupter, a photo coupler, etc. can be formed in a small size in addition to the light receiving element.

Since the lens 7 has a large numerical aperture NA and a high uniformity of the light flux density, it can be used for a condensing lens or an objective lens of an optical disc apparatus. In the case of an objective lens, parallel light is focused on the focal point, so that the traveling direction of the light is reversed from that in the case of an LED. In the case of an objective lens that injects parallel light from the direction of the rotation axis and collects it at the optical center position, the dimension of this optical center is called the beam waist diameter, and the beam waist diameter is 0.82λ / Since it can be set by NA, the optical axis lens 6 is used for CD of NA 0.45, the refractive exit surface 3 is used for DVD of NA 0.65, and the catadioptric interface 1 is used for BD of NA 0.85. If the distance is changed, it can be used for a multifocal lens for an optical disc.

約４％の界面反射を差し引いて各レンズの集光率を比較すると、図１１の球面レンズは約０．３８、図１２の球面レンズは約０．６９、楕円レンズ単体が約０．４６、図４の楕円レンズと反射屈折界面１などを組み合わせたレンズ全体は約０．９４である。従来の楕円レンズは約半分が発光素子側に全反射あるいは側方に射出して有効に活用出来ない光である。反射屈折界面１と間接反射面４でこの光を集光して効率が約２倍になる。図１２の発光素子が半径の約２倍位置の球面レンズに比べて約１．４倍の集光率による効率向上になり、同一光束を得る場合にＬＥＤ数を２７％削減出来る。狭指向角の図１１のレンズに比べて約２．５倍の集光率のためＬＥＤ数を６０％削減し、大幅にコストダウンが可能である。効率向上により発熱量も低下するので信頼性が向上する。あるいは同一温度上昇にしてヒートシンクの表面積を削減することも可能である。 The range from the focal point to the aperture diameter of the lens is called the aperture angle θ, and this sine value sin θ is displayed as a numerical aperture NA and used as an indicator of the brightness of the lens. In the illuminating device, the aperture angle on the light source side is called the condensing angle θ, but if the radiating angle is large, the converging angle can be increased, and therefore depends on the radiating angle of the illuminating device. Comparing the condensing angle with a collimator that converts to parallel light, the spherical lens in which the light emitting element in FIG. 11 is about 3 times the radius is about 25 °, and the light emitting element in FIG. Is about 47 °, and about 30 ° for the elliptical lens shown in FIG. On the other hand, the entire lens in which the catadioptric interface 1 and the indirect reflection surface 4 in FIG. 2 are combined is arranged so as to surround the focal point, so that light can be collected from a range of 80 °.
When Lambert's cosine law is integrated using the light emitting element surface as a uniform diffusing surface, the condensing rate of the light emitted from the light source to the hemispherical surface to the lens can be obtained by Equation 16. The remainder of the light collection rate is emitted to the side and a lot is lost.

When the condensing rate of each lens is compared by subtracting the interface reflection of about 4%, the spherical lens of FIG. 11 is about 0.38, the spherical lens of FIG. 12 is about 0.69, the elliptical lens alone is about 0.46, The total lens combining the elliptical lens of FIG. 4 and the catadioptric interface 1 is about 0.94. In the conventional elliptic lens, about half of the light is totally reflected to the light emitting element side or emitted to the side and cannot be used effectively. The light is collected by the catadioptric interface 1 and the indirect reflection surface 4 to double the efficiency. The light-emitting element of FIG. 12 improves efficiency by a light collection rate of about 1.4 times compared to a spherical lens at a position about twice the radius, and the number of LEDs can be reduced by 27% when obtaining the same luminous flux. Compared with the lens of FIG. 11 having a narrow directivity angle, the condensing rate is about 2.5 times, so that the number of LEDs can be reduced by 60%, and the cost can be greatly reduced. Since the amount of heat generation is reduced due to the improved efficiency, the reliability is improved. Alternatively, it is possible to reduce the surface area of the heat sink by increasing the same temperature.

Although the brightness unevenness of the LED exit surface is not a problem in an illumination device such as a ceiling lamp, the display surface of the signal light has a significant brightness unevenness due to the high brightness part of the LED and the dark part around it. In FIG. 15 of the conventional example, about 64% of the total light is concentrated in a region with an area ratio of about 8% near the optical axis, and the remaining 36% is emitted from the lens periphery, so the luminance ratio is 87: 0: 13. .
On the other hand, in FIG. 4, the light incident on the indirect reflection surface 4 is emitted from the catadioptric interface 1 outside the elliptical lens, and the light incident on the indirect reflection surface 4 is emitted from the refraction exit surface 3. When the ratio of these emitted lights is calculated by Equation 16, the elliptic lens is 50%, the catadioptric interface 1 is 13%, and the refractive exit surface 3 is 37%. Since the emission area ratio of the lens surface is about 1: 2.2: 2.4, the luminance ratio is about 74:16:11, and the luminance unevenness is improved as compared with the conventional example.

1. A conventional LED with a lens has a lens length / radius ratio of 3.1 for a spherical lens cylindrical part and a lens length / radius ratio of 2.5 for an elliptical lens cylindrical part, but the lens size is long. The size is reduced to less than half by 1.0 to 1.2.
2. The conventional LED is totally reflected near the boundary between the spherical surface and the cylindrical surface and leaks to the side surface near the top or multiple reflections in the direction of the light emitting element, resulting in a loss. 4 and exits from the refractive exit surface 3, such total reflection loss does not exist, and the optical path is clear.
3. In order to avoid total reflection loss with a conventional LED, a wide directivity angle is unavoidable. However, since the lens of the present application has no trade-off relationship, a narrow directivity distribution can be set independently without total reflection loss.
4). In the conventional spherical lens LED, ambient light becomes diffuse light of about 10 ° due to spherical aberration, but the lens in FIG. 4 can make light from the optical center almost parallel.
5. The light collection angle can be increased to about 80 °, and even if a surface-mounted LED having a light intensity half-value angle of 120 ° is used, most of the radiated light from the light emitting element can be utilized, contributing to efficiency improvement. If there is no unevenness of excitation light and fluorescent light flux, color unevenness and retroreflective loss of fluorescence as in a surface-mounted LED with a Fresnel lens, additive color mixing is possible if the directivity angle between the optical axis lens 6 and the catadioptric interface 1 is approximately matched. And is recognized as a complementary white color.
7). A hemispherical lens has large light flux unevenness, and even if it is reflected to the center of the lens by a diffusion process, it is refracted in the lateral direction at the exit surface and cannot be made uniform. The lens of the present application can be emitted from the catadioptric interface 1 and the refractive exit surface 3 to make the luminance ratio uniform, and the excitation light and fluorescence can be additively mixed and averaged by matching the directivity angles of the optical axis lens 6 and the catadioptric interface 1 It is.

Sectional drawing which shows the principle of the structure of the lens which provided the catadioptric interface 1, the side reflective surface 2, the refractive exit surface 3, and the indirect reflective surface 4 in contact with the edge part of a spherical lens Sectional drawing for demonstrating the function of the lens which provided the catadioptric interface 1, the side reflective surface 2, the refractive exit surface 3, and the indirect reflective surface 4 in contact with the edge part of a spherical lens A sectional view of a lens in which a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3 and an indirect reflecting surface 4 are provided in contact with the edge of an elliptic lens, and an incident toroidal surface 5 is provided on the incident surface. Cross-sectional view of a surface-mounted LED in which a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3, an indirect reflecting surface 4 are provided in contact with the edge of an elliptic lens, and an incident toroidal surface 5 is provided on an incident surface. Cross-sectional view of a surface-mounted LED in which a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3, and an indirect reflecting surface 4 are provided in contact with the edge of a spherical lens Cross-sectional view of a lead frame type LED in which a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3, and an indirect reflecting surface 4 are provided in contact with the edge of a spherical lens Cross-sectional view of a lead frame type LED in which a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3, and an indirect reflecting surface 4 are provided in contact with the edge of a spherical lens Cross-sectional view of a surface-mounted LED provided with a catadioptric interface 1, two side reflecting surfaces 2, a refractive exit surface 3, and an indirect reflecting surface 4 in contact with the edge of an elliptic lens Cross-sectional view of a lead frame type LED in which an adapter comprising a catadioptric interface 1, a side reflecting surface 2, a refractive exit surface 3, and an indirect reflecting surface 4 is provided at the edge of an elliptic lens. Sectional view of a lens array formed by moving the position of the refractive exit surface 3 Conventional lens having a structure in which a light emitting element is provided at the internal focal point of a spherical lens A conventional lens having a structure in which a light emitting element is provided on the tip side from the internal focal point of a spherical lens Conventional surface-mount fluorescent white LED using Fresnel lens Conventional lens that emits totally reflected light from the side of hemispherical lens and diffused light from light source from flat surface A conventional lens having a convex surface on the light-emitting element facing surface of the concave incident surface of FIG. Conventional lens in which the reflection surface and the concave incident surface of the hemispherical lens of FIG.

Example 1
FIG. 3 is a sectional view showing the lens 7 using the incident toroidal surface 5 alone. The curvature radius and the focal length f1 of the incident toroidal surface 5 are such that when polymethyl methacrylate having a refractive index n2 = 1.49 is used as the lens material and the curvature radius r = 1 mm, the focal length f1 = 2.04 mm according to Equation 11. Since the incident toroidal surface 5 can be converted into parallel light in cross-section, when θ is set to 36 °, it is a conical surface having an inclination angle ω 68 ° formed by the catadioptric interface 1 and the rotation axis and an inclination angle χ 50 ° of the side reflection surface 2. . The refractive exit surface 3 can be emitted parallel to the optical axis according to Equation 12. Since the catadioptric interface 1 is a conical surface, the reflected light of the indirect reflection surface 4 is parallel in cross section. For this reason, the indirect reflection surface 4 is a toroidal surface whose rotation axis is inclined inward from the y-axis of the parabola. The optical axis lens 6 can emit parallel light when an elliptical lens according to Equation 15 is used.
In FIG. 3, the focal point is indicated by one point. However, when it is used as a multifocal lens for an optical disc, there are a plurality of focal positions according to the disc thickness. FIG. 3 shows an example of parallel light, but it can be changed to diffused light. In the case of diffuse light, the optical axis lens 6 changes the optical center position to a position having a small curvature radius ratio, shifts the optical center of the incident toroidal surface 5 from the focal point, and brings the indirect reflection surface 4 closer to the conical surface. 1 emission light can be changed to diffused light.
FIG. 3 illustrates two connecting portions 17 for fitting the lens to the support member at the lower portion and the upper portion of the indirect reflection surface 4. The connecting portion 17 is shown as an example in which a threading process can be performed and the directivity angle can be adjusted by adjusting the position, but the connecting portion 17 can be changed to a taper-like structure or the like. An illumination device, an optical device, or the like can be manufactured by combining the lens 7 with an arbitrary LED, light receiving element, or the like. Since an arbitrary lighting device can be manufactured by changing the shape and dimensions of the support substrate, there is a feature that design freedom is high.
The LED in which the light emitting element is embedded needs to be provided with an external lens to adjust the directivity angle. However, the lens 7 in FIG. Useful for devices. In an application where the position is frequently adjusted such as a spot lighting device, a metal threaded part may be fitted to the lens 7. When the lens 7 shown in FIG. 3 is used for narrow directivity application such as a headlight with a large amount of light, a lighting device can be manufactured by fitting a plurality of lenses 7 to a substrate.

Example 2
An example of a surface mount LED using the incident toroidal surface 5 is shown in FIG. If the light emitting element 9 is embedded in the sealing resin 10 and provided at the focal point 20 of the incident toroidal surface 5, the light emitting element 9 can be converted into parallel in a sectional view. Since the surface-mounted LED using the incident toroidal surface 5 requires a low refractive index layer such as air between the sealing resin 10, the sealing resin and the lens 7 are separated. Except when a reflective film is formed, a gap 8 is required to make the indirect reflection surface 4 and the side reflection surface 2 a total reflection surface. In the drawing, the main part is shown, and the connection of the light emitting element 9 and the like are omitted.
In an example in which the refractive exit surface 3 is perpendicular to the optical axis, when the angle θ of the incident toroidal surface 5 is set to 38 °, the inclination ω of the catadioptric interface 1 is 64 ° and the inclination χ of the side reflection surface 2 is 45 °. It is a conical surface. Since it enters perpendicularly to the refractive exit surface 3, it can go straight and exit parallel to the optical axis, but it is also easy to emit diffused light with a curved surface. When diffusing light is emitted from the refractive exit surface 3, the diffusion angles can be matched by making the indirect reflection surface 4 close to a conical surface rather than a parabolic surface. The optical axis lens 6 can emit parallel light when an elliptical lens according to Equation 15 is used. Since this structure is a structure in which the light emitting element 9 does not directly irradiate the refractive exit surface 3, all light having a diffusion angle of about 80 ° can be emitted almost parallel to the optical axis.

Example 3
FIG. 5 shows a cross-sectional view of a surface-mounted LED having a diffusion angle of 12 ° using the structure of FIG. When used as a single lens 7, the incident surface may be changed to a concave spherical surface. The optical axis lens 6 has a diffusion angle of 10 ° when the light emitting element 9 is provided at a position approximately 2.3 times the radius of curvature from the tip, and ± 5 ° when displayed symmetrically with respect to the optical axis. This includes a diffusion angle of about 12 ° including an error due to the size of the light emitting element. The boundary between the optical axis lens 6 and the catadioptric interface 1 is set at a point where the radiation angle θ is 33 °, and each dimension can be set by the ratio of the coordinates (1, 1.54) of the boundary. The center of curvature C1 (1.9, −0.28) of the catadioptric interface 1 and the radius 1.73. The reflected light from the catadioptric interface 1 becomes convergent light and enters the convex side reflecting surface 2 at an incident angle of 48 ° to 50 °. The reflected light from the side reflecting surface 2 is incident on the refracting exit surface 3 as light that is nearly parallel in a cross-sectional view. The refracting exit surface 3 is an inclined curved surface, and the exit direction is in the range of 0 to 12 ° with respect to the optical axis. Inject at. The directivity angle of the emitted light at the most peripheral portion is about 12 °, but the ratio larger than the radiation angle ± 7.5 ° of the optical axis lens 6 is about 4% of the total light. The light emitted from the light emitting element 9 to the side is reflected by the indirect reflection surface 4, is incident on the catadioptric interface 1 and refracted, and is emitted forward within a range of ± 3 °. The indirect reflection surface 4 is a toroidal surface intermediate between the paraboloid and the conical surface, and the rotation axis is inclined inward from the y-axis of the parabola.
FIG. 5 shows an example in which the light emitting element side of the lens is flattened and the excess amount of the sealing resin flows out. However, if the sealing resin around the light emitting element 9 is molded with a spherical surface, the lens goes straight even if a gap is generated. The lens 7 may be formed of a concave spherical surface. In order to flow out the surplus amount of the sealing resin, a space is provided below the gap 8 between the indirect reflection surface 4 and the case, and the surplus amount is obtained by injecting the sealing resin more than the sealing space volume and then covering the lens. Can be prevented from adhering to the indirect reflecting surface 4.
When the refractive indexes of the lens 7 and the sealing resin are different, each reflecting surface is designed in consideration of the influence of refraction. Direct light having a radiation angle θ from the light emitting element 9 of about 3 ° between 47 and 50 ° is incident on the refractive exit surface 3 and refracted and emitted in the direction of 60 ° from the optical axis. This light quantity ratio is about 4% of the whole, so it is extremely small compared to about 30 to 60% of the conventional lens having a cylindrical surface, but this is improved by reflecting the case reflecting surface 15 in the optical axis direction.

Example 4
FIG. 6 shows a lead frame type LED having the structure shown in FIG. When a light emitting element is provided at a position about 2.1 times the spherical lens radius in the optical axis lens, the diffusion angle φ of light from the light emitting element is 15 °. The indirect reflection surface 4 is substantially a conical surface in order to widen the diffusion angle of the emitted light from the catadioptric interface 1. FIG. 5 shows an example in which the phosphor 11 is used. When the diffusion angle based on the size of the phosphor is included, the diffusion angle φ is about 20 °. In the LED using the phosphor, the length of the phosphor layer changes depending on the direction of the inclined light, so that color separation is likely to occur. However, the directivity angles of the optical axis lens and the catadioptric interface 1 in FIG. Since the light is emitted, the excitation light and the fluorescence are added and averaged to prevent color separation.
Even if the lead frame is extended to the side by using a space where the diameter of the side reflection surface 2 protrudes from the conventional cylindrical surface, and the bottom side dimension is shortened, the distance from the solder tank to the light emitting element during solder mounting and Thermal resistance is equivalent. With this structure, the height can be reduced and the height can be about 0.6 times the diameter compared to a long shape like a conventional shell. 11 has a diameter of 5 mm, a height of 10 mm, and a distance between lead frames of 2.5 mm, so the stability during mounting is poor. However, when configured with the same volume as this, the diameter is about 7 mm, the height is about 5 mm, the lead Since the distance between the frames is 5 mm and the stability is good, the mounting efficiency is improved.

Example 5
FIG. 7 shows an example of a lead frame type LED having a diffusion angle of 30 ° smaller than the radius of curvature of FIG. In this optical system, as shown in FIG. 1, the radius of curvature of the catadioptric interface 1 is small, so that the diameter is about 10% smaller than that in FIG. When the optical axis lens 6 is provided with a light emitting element at a position about twice the radius of the spherical lens, the diffusion angle φ from the light emitting element and the phosphor is about 30 °. In accordance with this, the catadioptric interface 1, the side reflecting surface 2, the refractive exit surface 3, and the indirect reflecting surface 4 are set to have a diffusion angle φ of about 30 °. As described in paragraph 0027, the fifth embodiment has a feature that color separation can be prevented by averaging and mixing excitation light and fluorescence in the same direction over a diffusion angle of φ30 °. The indirect reflection surface 4 is a conical surface in order to widen the diffusion angle of the light emitted from the catadioptric interface 1. This optical system can be used to change to a surface-mounted LED having a diffusion angle of 30 °.
Since the diameter of the side reflecting surface 2 protrudes from the conventional cylindrical surface, the space is used to extend the lead frame to the side to reduce the height. It is possible to make the diameter smaller than in the fourth embodiment.

Example 6
An embodiment of the surface-mounted LED according to FIG. 8 that emits parallel light to the optical axis will be described. Since the radius of curvature of the side reflecting surface 2 can be set larger than that of FIGS. 1 to 3, the side reflecting surface 2 is converted into parallel light by setting the focal length of the side reflecting surface 2 equal to the convergence distance to the focal point 20 of the ellipse. Center of curvature C1 of the catadioptric interface 1 (1.92, -0.38), r = 2.31, Center of curvature C1 of the side reflecting surface 2 (2.27, 0), r = 1.5, As a result, almost parallel light can be emitted. The side reflecting surface 2 is reflected obliquely upward by the equation (12), and is converted by the refractive exit surface 3 to be parallel to the optical axis by the equation (13).
Compared with the example in which the incident toroidal surface 5 is used for conversion, this structure is characterized in that the incident surface is made flat and the productivity is improved. In order to allow the surplus amount of the sealing resin to flow out, a space indicated by a V-shape is provided below the gap 8 in the case, and if the sealing resin is injected and then covered with a lens, the surplus amount flows out into this space. Therefore, the influence on the indirect reflection surface 4 can be prevented. When the refractive indexes of the lens 7 and the sealing resin are different, it is necessary to consider the influence of refraction. If the sealing resin 10 is molded in a spherical shape and the incident surface of the lens 7 is made spherical, even if there is a space, it will go straight, so there will be no effect.

Example 7
When the lens 7 composed of the catadioptric interface 1, the side reflecting surface 2, the refractive exit surface 3, the indirect reflecting surface 4 and the optical axis lens 6 is assembled into a lens array, an illumination device can be configured in combination with the LED 16. I can do it. An example in which a lens array is configured at the time of molding is shown in FIG. Since it is difficult to secure the thickness of the connecting portion in the structure of the refractive exit surface 3 in FIG. 2, the thickness of the connecting portion increases when the refractive exit surfaces 3 are moved to the connection counterpart side. Since the refraction direction does not change even if the refracting light exit surfaces 3 move toward each other, the illuminating device can be configured while maintaining the directivity angle.
If the lens array is connected at multiple points to form a plane, and the LEDs 16 are arranged on the substrate 14 at the pitch of the lens array, a surface illumination device can be easily manufactured. When connected at two points as shown in FIG. 10, a rod-shaped or annular lens array is formed. However, if a lens is sandwiched by a support (not shown), strength can be ensured by the support. If a rod-like or annular lens array is arranged on the substrate 14 together with the LEDs 16 or the like, it can be easily replaced with a lighting device using a linear fluorescent tube or an annular fluorescent tube by changing the power supply unit.
In addition to forming the lens array at the time of molding, it is also possible to form a lens array by fitting a plurality of lenses 7 in FIG.

Example 8
If an area composed of the catadioptric interface 1, the side reflecting surface 2, the refracting exit surface 3 and the indirect reflecting surface 4 is used as an adapter and is put on the conventional LED 16 with a lens, the light that is totally reflected toward the top portion is reflected and reflected. 1 and the refractive exit surface 4 can be emitted in the optical axis direction. FIG. 9 shows a state in which an adapter in a region constituted by the catadioptric interface 1, the side reflecting surface 2, the refractive exit surface 3, and the indirect reflecting surface 4 is put on an elliptic lens. If a gap is generated at the interface between the conventional LED lens and the adapter, the effect is reduced. Therefore, if the adhesive surface 17 is covered with an adhesive, reflection of the gap can be prevented.

1: catadioptric interface 2: side reflecting surface 3: refractive exit surface 4: indirect reflecting surface 5: incident toroidal surface 6: optical axis lens 7: lens 8: air gap
9: Light emitting element 10: Sealing resin 11: Phosphor 12: Case 13: Electrode / lead frame 14: Substrate 15: Case reflecting surface 16: LED
17: Joining / connecting part 18: Bonding wire 19: Rotating shaft 20: Focus

Claims (12)

A structure in which a catadioptric interface in contact with the edge of the optical axis lens is provided at an angle that is not less than a critical angle with respect to the optical center, and an indirect reflecting surface is provided on the side of the optical center,
The light from the optical center is totally reflected laterally at the catadioptric interface, and the light from the optical center is reflected by the indirect reflecting surface and then refracted at the catadioptric interface and emitted forward. lens. The lens according to claim 1, wherein the catadioptric interface is a toroidal surface or a conical surface obtained by rotating a curvature circle, a parabola, or a straight line about the optical axis. A lens having a convex toroidal surface between the catadioptric interface and the optical center of the lens according to claim 1, and refracted light from the convex toroidal surface is incident on the catadioptric interface. It has a structure in which a side reflection surface or a cone reflection surface and a refractive exit surface are provided on the side of the catadioptric interface, and the side reflective surface reflects the reflected light from the catadioptric interface and emits it forward from the refractive exit surface. The lens according to claim 1, wherein: The lens according to claim 1, wherein the indirect reflection surface is a paraboloid, a straight line, a curvature circle, or a curved rotation surface that is a combination thereof. 5. The lens according to claim 4, wherein the side reflecting surface is disposed so that light reflected by the catadioptric interface is incident at a critical angle or more. The lens according to claim 1, wherein the lens has a structure in which a fitting portion is provided in contact with the indirect reflection surface, and the position can be adjusted. A catadioptric interface that touches the edge of the optical axis lens is provided at an angle that is greater than or equal to the critical angle with respect to the optical center, and the side reflecting surface, the refractive exit surface, the indirect reflecting surface, and the position of the optical center are located on the side. An illumination device comprising a light source. 9. The excitation light and the fluorescence are mixed by making the directivity angle of the light refracted by the reflected light of the indirect reflection surface at the catadioptric interface substantially coincide with the directivity angle of the optical axis lens. The lighting device described. 9. The method according to claim 8, wherein a space is provided below the gap between the indirect reflection surface and the case, and the sealing resin is poured and then the lens is covered to discharge an excess amount of the sealing resin into the space. The lighting device described. A catadioptric interface that touches the edge of the optical axis lens is provided at an angle that is greater than or equal to the critical angle with respect to the optical center, and the side reflecting surface, the refractive exit surface, the indirect reflecting surface, and the optical center are located on the sides A light receiving device comprising a light receiving element. The catadioptric interface in contact with the edge of the optical axis lens is provided at an angle that is equal to or greater than the critical angle with respect to the optical center, and the side reflecting surface, the refractive exit surface, the indirect reflecting surface, and the position of the optical center are located on the sides. An optical apparatus characterized in that the optical waist is a beam waist position of an optical disk apparatus.

Images