JP2010123293A - Illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination device capable of irradiating luminous flux of a desired irradiation pattern in a wide range of irradiation distance. <P>SOLUTION: A reflection type LED 12 is adopted as a light source, and light irradiated from a light-emitting element 17 arranged at a first focus F1 of the reflection surface 14 is once converged at a second focus F2, and then, made to enter into a lens portion 33 to be converted into parallel light. Thereby, accurate parallel light can be formed. Then, the luminous flux converted into parallel light is made to enter into a cylindrical lens 35 and, by changing only one axial direction into a diffusion direction, linear illumination light is formed. Thereby, irrespective of irradiation distance, linear light of a certain pattern width can be irradiated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device that forms a light beam having a desired shape using a light emitting diode as a light source.

2. Description of the Related Art In recent years, lighting devices that employ light-emitting diodes (LEDs) as light sources have become widespread in lighting devices that emit light beams of various desired shapes as illumination light. For example, Patent Document 1 discloses a so-called bullet-type LED in which a condensing lens is integrally formed at a tip portion of an optical member in which a light-emitting element is embedded, and light emitted from the bullet-type LED with a predetermined directivity characteristic only in one axial direction. There is disclosed an illuminating device including a cylindrical lens that forms linear illumination light by changing in a condensing direction.
JP 2001-155110 A

  However, although the technique disclosed in Patent Document 1 described above can obtain linear light having a desired width in the vicinity of the focal point of the cylindrical lens, a linear pattern is formed at a position far away from the focal point of the cylindrical lens. There is a possibility that it becomes difficult to obtain a sharp and bright irradiation pattern due to an increase in the width.

  An object of this invention is to provide the illuminating device which can irradiate the light beam of a desired irradiation pattern in a wide irradiation distance range.

  The present invention provides a reflective light emitting diode that reflects light from a light emitting element disposed at a first focal point of a concave reflective surface to the second focal point and collects the light from the reflective light emitting diode. And a lens member that converts light into parallel light.

  According to the illumination device of the present invention, it is possible to irradiate a light beam having a desired irradiation pattern in a wide irradiation distance range.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 5 relate to a first embodiment of the present invention, FIG. 1 is an exploded perspective view showing a main part of the lighting device, and FIG. 2 (a) shows the lighting device along the line II in FIG. It is principal part sectional drawing shown, (b) is principal part sectional drawing which shows an illuminating device along the II-II line | wire of FIG. 1, FIG. 3 is principal part sectional drawing of reflection type LED, FIG. 4 (a) is FIG. It is explanatory drawing which shows the behavior of the illumination light in the cross section of (a), (b) is explanatory drawing which shows the behavior of the illumination light in the cross section of FIG.2 (b), FIG. 5 shows the structure of the reflective surface of reflection type LED. It is explanatory drawing.

  The illuminating device 1 shown in FIGS. 1 and 2 is, for example, a linear illuminating device that irradiates a linear light beam as illumination light. The illuminating device 1 includes a light source unit 10 having a light emitting diode (LED) 12 as a light source, and The light source unit 10 has a housing 30 that is crowned.

  The light source unit 10 has an LED substrate 11. The LED substrate 11 has, for example, a substantially rectangular shape on a plane, and holds the LED 12 by soldering or the like at a substantially central portion thereof. Here, the LED 12 is composed of a reflective light emitting diode.

  Specifically, as shown in FIGS. 2 and 3, the LED 12 includes a reflecting member 13. In the present embodiment, the reflecting member 13 has a flat and substantially cubic shape, and a reflecting surface 14 having a partial spheroid shape is recessed on one surface (top surface) 13 a of the reflecting member 13. . In the present embodiment, the reflecting member 13 is made of, for example, a resin material in which a concave surface having a partial spheroidal shape is formed on the top surface 13a side. And the reflective surface 14 is formed by forming metal films, such as aluminum, on this concave surface. Here, one focal point (first focal point F1) of the spheroid that defines the shape of the reflecting surface 14 is set to be deviated slightly inward from the position flush with the top surface of the reflecting member 13. Yes. On the other hand, the other focal point (second focal point F2) of the spheroid is set at a position that is separated from the top surface 13a of the reflecting member 13 by a predetermined distance outward in the vertical direction. Thereby, the reflecting surface 14 can reflect the light emitted from the first focal point F <b> 1 inside the reflecting member 13 and condense it on the second focal point F <b> 2 outside the reflecting member 13.

  The reflective member 13 is provided with a pair of lead frames 15 and 16 along, for example, side walls facing each other. The midway of one end side of each lead frame 15, 16 is bent toward the top surface 13 a side of the reflecting member 13, whereby one end of each lead frame 15, 16 faces the reflecting surface 14. One of the lead frames 15, 16 is extended to a position corresponding to the first focal point F <b> 1 at one end of the lead frame 15, and the reflecting surface 14 is provided at one end of the extended lead frame 15. The light emitting element 17 is mounted on the side facing the surface. As a result, the lead frame 15 holds the light emitting element 17 at a position that coincides with the first focal point F1 of the reflecting surface 14. One end of the other lead frame 16 is electrically connected to the light emitting element 17 via a lead wire 18. On the other hand, the middle of the other end side of each lead frame 15, 16 is bent, for example, to the surface side facing the top surface 13 a to form terminal portions 15 a, 16 a, and each of these terminal portions 15 a, 16 a is soldered The LED board 11 is electrically connected by attaching or the like. Accordingly, the lead frames 15 and 16 can electrically connect the anode and the cathode of the light emitting element 17 to the LED substrate 11 and cause the light emitting element 17 to emit light.

  In addition, a light transmissive material 19 is filled in the concave portion surrounded by the reflection surface 14 of the reflection member 13, and the light emitting element 17 is sealed in the concave portion by the light transmissive material 19. As the light transmissive material 19, for example, a material having a refractive index higher than the refractive index “1” of air and lower than the refractive index of the light emitting element 17 (for example, around “3”) is used. A transparent resin material having a refractive index of about “1.6” to “1.7” is preferably used.

  The housing 30 accommodates therein a lens optical system 31 for controlling light emitted from the LEDs 12. In the present embodiment, the housing 30 has a substantially rectangular tube shape, and an inward flange 30a is formed at the tip. The base end portion of the housing 30 is set as a contact portion of the light source unit 10 with respect to the LED substrate 11. And the base end part of the housing | casing 30 is being fixed with respect to the LED board 11 by adhesion | attachment or screwing.

  The lens optical system 31 forms a linear illumination light by changing a light emitted from the LED 12 into parallel light, and changing the light converted into parallel light by the lens member 33 in a diffusing direction only in one axial direction. And a cylindrical lens 35.

  The lens member 33 is made of, for example, a light-transmitting resin molded product in which a biconvex lens portion 33b is integrally formed inside an annular flange portion 33a that is in sliding contact with the inner periphery of the housing 30. On the incident side of the lens member 33, an annular spacer 38 is in contact with the flange portion 33 a, and the lens member 33 is disposed to face the LED 12 through the spacer 38. Here, as shown in FIG. 2, the lens member 33 is arranged so that the optical axis of the lens portion 33 b coincides with the optical axis O of the LED 12. Furthermore, the entrance surface of the lens portion 33 b is positioned by the spacer 38 at a position offset farther than the second focal point F <b> 2 of the LED 12.

  For example, the cylindrical lens 35 has a light-transmitting property in which a semi-convex lens portion 35b having a substantially semi-cylindrical shape projecting toward the emission side is integrally formed inside an annular flange portion 35a that is in sliding contact with the inner periphery of the housing 30. It is composed of a resin molded product. On the incident side of the cylindrical lens 35, an annular spacer 39 that abuts on the flange portion 33 a on the emission side of the lens member 33 is connected to the flange portion 35 a. On the other hand, on the emission side of the cylindrical lens 35, the inward flange 30a of the housing 30 is in contact with the flange portion 35a.

  In the illumination device 1 having such a configuration, the light emitted from the light emitting element 17 of the LED 12 is once condensed at the second focal point F2 by being reflected by the reflecting surface 14, and then the lens portion 33b of the lens member 33. Is incident on. The light beam incident on the lens unit 33b is converted into parallel light by refraction. Further, the light beam converted into parallel light by the lens member 33 is incident on the lens portion 35b of the cylindrical lens 35 and is converted into a linear light beam by being refracted only in one axial direction in the diffusing direction. Thereby, for example, linear light suitable for a barcode reader or the like is formed.

  According to such an embodiment, the reflective LED 12 is employed as the light source, and the light emitted from the light emitting element 17 disposed at the first focal point F1 of the reflecting surface 14 is once condensed at the second focal point F2. Then, the light is incident on the lens member 33 and converted into parallel light, thereby generating parallel light with high accuracy. The light beam thus converted into parallel light is incident on the cylindrical lens 35, and only one axis direction is changed to the diffusion direction while maintaining the width of the light beam converted into parallel light to form linear illumination light. By doing so, it is possible to irradiate linear light of a sharp and bright irradiation pattern with a constant pattern width regardless of the irradiation distance.

  Here, in order to improve the accuracy of condensing the light emitted from the reflective LED 12 in consideration of the influence of refraction and the like in the light transmissive material 19, and further improve the accuracy of the parallel light converted by the lens member 33. For example, as shown in FIG. 5 (a), the reflecting surface 14 formed on the reflecting member 13 of the LED 12 may be formed of a polynomial aspherical surface.

This polynomial aspherical surface can be expressed by the following equation, for example, when an XYZ coordinate system is defined as shown in FIG.

Here, in the equation, z is a zag amount of a surface parallel to the Z axis, c is a vertex curvature, k is a conic constant, and C _2n is a 2n-order aspherical constant.

In addition, the polynomial aspherical surface shown in FIG.
Radius: 5.08000 [mm]
Conic constant: -0.37169
Fourth-order (ie, n = 2) aspheric constant C ₄ = 0.00914
Sixth-order (ie n = 3) aspheric constant C ₆ = −0.00356
Eighth order (ie n = 4) aspheric constant C ₈ = 0.00064
10th-order (ie, n = 5) aspheric constant C ₁₀ = −0.00005
12th-order (ie, n = 6) aspheric constant C ₁₂ = 0.00000
14th-order (ie n = 7) aspheric constant C ₁₄ = 0.00000
A 16th-order (ie, n = 8) aspheric constant C ₁₆ = 0.00000
18th-order (ie, n = 9) aspheric constant C ₁₈ = 0.00000
20th-order (ie, n = 10) aspheric constant C ₂₀ = 0.00000
Is a polynomial aspherical surface designed as

  By optimizing the reflecting surface 14 with such a polynomial aspheric surface, in particular, the light reflected in the vicinity of the outer ring of the reflecting surface 14 can also be accurately focused on the second focus. Further, by optimizing the reflecting surface 14 by a polynomial aspheric surface, it is not necessary to arrange the light emitting element 17 at the first focal point F1 in a strict sense, and the degree of freedom in designing the LED 12 can be improved. As a comparative example, FIG. 5B shows a simulation result on the behavior of light on the reflecting surface 14 formed along the partial spheroid.

  Next, FIGS. 6 and 7 relate to the second embodiment of the present invention, FIG. 6 is a cross-sectional view of the main part of the illumination device, and FIG. 7 is an explanatory view showing the behavior of illumination light in the cross section of FIG. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 6, the lens member 33 of the present embodiment has a lens portion 34 instead of the lens portion 33b, and this lens portion 34 is constituted by an incident surface 34a constituted by a convex lens curved surface and a concave lens curved surface. And an exit surface 34b.

  Specifically, the incident surface 34a is constituted by, for example, a convex lens surface having a spherical surface as a basic shape. The incident surface 34a is disposed on the nearer side (the first focal point F1 side) than the second focal point F2 of the LED 12, and refracts incident light from the LED 12 in a further condensing direction. On the other hand, the exit surface 34b is constituted by, for example, a concave lens surface whose basic shape is a spherical surface having a smaller diameter than the entrance surface 34a. The exit surface 34b is disposed on the near side (incident surface 34a side) with respect to the in-focus position by the entrance surface 34a, and converts the light collected by the entrance surface 34a into parallel light by refraction. Here, the specifications and arrangement of the entrance surface 34a and the exit surface 34b are set based on experiments, simulations, and the like. In this case, in particular, the specification of the exit surface 34b, the relative position with respect to the entrance surface 34a, and the like are arbitrarily set according to the required pattern width, density, etc. of parallel light. That is, for example, the output surface 34b is set near the in-focus position by the incident surface 34a as the parallel light with a narrow pattern width and high density is required.

  Further, in the present embodiment, a light shielding mask 45 is interposed between the lens member 33 and the cylindrical lens 35 via a spacer 46. The light-shielding mask 45 is provided with a slit 45a facing the exit surface 34b of the lens member 33, whereby the light-shielding mask 45 cuts stray light and allows only suitable parallel light to pass.

  According to such an embodiment, the lens portion 34 of the lens member 33 is configured by a convex / concave lens in which the incident surface 34a is configured by a convex lens surface and the output surface 34b is configured by a concave lens surface, whereby the second LED 12 is configured. Even when the lens member 33 is disposed on the front side of the focal point F2, high-density parallel light with a small pattern width can be formed. Therefore, the distance in the optical axis direction from the LED 12 to the lens member 33 can be greatly shortened, and the illumination device 1 can be effectively downsized.

  In the first and second embodiments described above, an example in which the cylindrical lens 35 is disposed on the exit side of the lens member 33 in order to form a linear light beam has been described. For example, a cylindrical lens is provided. By constructing the illumination device by omitting 35, it is also possible to use the illumination device as a light source for a pointer that indicates a target with a point light beam. Even in this case, the light emitted from the light-emitting element 17 is once controlled in the condensing direction by the reflecting surface 14 and converted into parallel light by the lens member 33, so that a light beam having a sharp and bright irradiation pattern can be obtained in a wide irradiation distance range. Can be irradiated.

  Next, FIGS. 8 and 9 relate to a third embodiment of the present invention, FIG. 8 is an explanatory view of an illumination device and an irradiation image, and FIG. 9 is a plan view of a light shielding mask. In addition, about the structure similar to the above-mentioned 1st Embodiment, a same sign is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 8, in the illuminating device 1 of the present embodiment, the light source unit 10 includes a plurality of (for example, two) LEDs 12 mounted on an LED substrate 11 to constitute a main part. Here, among these LEDs 12, one LED 12 is configured by, for example, a blue LED in which the light emitting element 17 emits blue light, and the other LED 12 is configured by, for example, a red LED in which the light emitting element 17 emits red light.

  Further, the lens member 33 is provided with a plurality of lens portions 33b facing each LED 12, and each lens portion 33b converts incident light from the facing LED 12 into parallel light.

  A projection lens 50 is provided on the exit side of the lens member 33. In the present embodiment, the projection lens 50 has lens portions 50b facing the respective lens portions 33b of the lens member 33 inside the flange portion 50a, and is converted into parallel light by the respective lens portions 33b of the lens member 33. The projected light is projected by each corresponding lens unit 50b. In this case, the projection lens 50 is set so that a part of the light beam projected by each lens unit 50b is superimposed over a predetermined projection distance.

  A light shielding mask 52 is interposed between the lens member 33 and the projection lens 50 via a spacer 53. As shown in FIG. 9, the light shielding mask 52 is provided with a light transmitting hole 52a that allows only passage of a light beam having a predetermined shape in a region facing each lens portion 33b. Then, the light beams that have passed through the respective light transmitting holes 52a are projected by the respective lens portions 50b of the projection lens 50, so that it is possible to irradiate the light beams having a desired irradiation pattern.

  In this case, particularly, as shown in FIG. 8, when illuminating light is irradiated to the object 55 that is spaced from the illumination device 1 by a preset projection distance, a part of the projection light from each lens unit 50 b is preferably superimposed. Thus, a projection image rich in variations can be formed.

  Next, FIGS. 10 and 11 relate to a fourth embodiment of the present invention, FIG. 10 is an explanatory view of an illumination device and an irradiation image, and FIG. 11 is a plan view of a light shielding mask. In addition, about the structure similar to the above-mentioned 3rd Embodiment, a same sign is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 10, in the illuminating device 1 of the present embodiment, the projection lens 50 is provided with a single lens portion 51 that faces the lens portions 33 b of the lens member 33 and faces each other.

  Further, as shown in FIG. 11, the light shielding mask 52 interposed between the lens member 33 and the projection lens 50 allows only passage of a light beam having a predetermined shape in a region facing each lens portion 33b. A light transmitting hole 52a is provided. Then, the light beam having passed through each light transmitting hole 52a is projected by the lens unit 51 of the projection lens 50, so that the light beam having a desired irradiation pattern can be irradiated. In this case, as shown in FIG. 10, the illumination device 1 projects an irradiation image for each light transmission hole 52 a corresponding to each lens unit 33 b independently onto the target 55.

  In each of the above-described embodiments, an example in which each lens portion is designed with a spherical surface or the like as a basic shape has been described. However, the present invention is not limited to this, and each lens portion may be aspherically designed. Is possible.

The exploded perspective view which shows the principal part of the illuminating device in connection with the 1st Embodiment of this invention. FIG. 2A is a cross-sectional view of the main part showing the lighting device along the line II in FIG. 1; FIG. 2B is a cross-sectional view of the main part showing the lighting device along the line II-II in FIG. Same as above, sectional view of the main part of the reflective LED 2A is an explanatory diagram showing the behavior of illumination light in the cross section of FIG. 2A, and FIG. 2B is an explanatory diagram showing the behavior of illumination light in the cross section of FIG. As above, an explanatory diagram showing the configuration of the reflective surface of the reflective LED Sectional drawing of the principal part of an illuminating device in connection with the 2nd Embodiment of this invention. As above, an explanatory diagram showing the behavior of illumination light in the cross section of FIG. Explanatory drawing of an illuminating device and an irradiation image in connection with the 3rd Embodiment of this invention. Same as above, top view of shading mask Explanatory drawing of an illuminating device and an irradiation image in connection with the 4th Embodiment of this invention. Same as above, top view of shading mask

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Illuminating device, 10 ... Light source unit, 11 ... LED board, 12 ... Reflection type light emitting diode, 13 ... Reflective member, 13a ... Top surface, 14 ... Reflective surface, 15 ... Lead frame, 15a ... Terminal part, 16 ... Lead Frame, 16a ... terminal part, 17 ... light emitting element, 18 ... lead wire, 19 ... light transmitting material, 30 ... housing, 30a ... inward flange, 31 ... lens optical system, 33 ... lens member, 33a ... flange part, 33b ... Lens part, 34 ... Lens part, 34a ... Incident surface, 34b ... Output surface, 35 ... Cylindrical lens, 35a ... Flange part, 35b ... Lens part, 38 ... Spacer, 39 ... Spacer, 45 ... Shading mask, 45a ... Slit, 46 ... Spacer, 50 ... Projection lens, 50a ... Flange, 50b ... Lens, 51 ... Lens, 52 ... Shading mask, 52a ... Translucent hole, 3 ... spacer 55 ... target, F1 ... first focal point, F2 ... second focal point, O ... optical axis

Claims (4)

A reflective light emitting diode that reflects light from the light emitting element disposed at the first focal point of the concave reflective surface at the reflective surface and collects the light at the second focal point;
And a lens member that converts light from the reflective light emitting diode into parallel light.   The illumination device according to claim 1, further comprising a cylindrical lens that changes the parallel light from the lens member in a diffusing direction only in one axial direction to form linear illumination light.   The lens member includes an incident surface composed of a convex lens surface and an exit surface composed of a concave lens surface. After the incident light is refracted in the condensing direction by the incident surface, parallel light is emitted by the exit surface. The illumination device according to claim 1, wherein the illumination device outputs the light after being converted into a light beam.   The illumination device according to any one of claims 1 to 3, wherein a reflective surface of the reflective light emitting diode is configured by a polynomial aspherical surface.

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