JP5180269B2 - Lighting device - Google Patents

Description

  The present invention relates to an illuminating device, and more particularly to a structure of an illuminating device suitable as illumination for inspection of an optical member such as an optical lens.

  In general, when an optical lens is inspected, the surface of the optical member is inspected for scratches, dirt, and the like in a state in which the optical member such as the optical lens is irradiated with light emitted from the illumination device. In this case, the inspection may be performed based on an image obtained by photographing the optical member illuminated by the illumination device. In recent years, many lighting apparatuses using LEDs (light emitting diodes) as light sources have been provided. In addition, in order to be able to detect scratches and dirt on the optical member with high contrast, the light emitting portion is configured in a ring shape (annular illumination), and the surface of the optical lens or the like is roughened to be diffusely reflected. A device using a light diffusing means such as the above has been proposed (see Patent Documents 1 to 3 below).

JP 2007-10380 A JP 2008-139708 A JP 2008-108618 A

  However, since the conventional illumination device for inspection uses LED elements with a plurality of resin lenses, the light intensity is insufficient for the apparatus to be large, and the resin lens of the LED element. There is a problem that the device must be designed on the premise of directivity by. In addition, when diffusing light by roughening the lens surface or the like of the exit portion of the illumination light, the illumination light is scattered at the exit portion, so that sufficient light condensing performance cannot be obtained and illumination efficiency is reduced. There is a problem of doing.

  In addition, it is conceivable to use an LED light source with a large amount of illumination for arranging a plurality of LED chips not accompanied by a resin lens (for example, a multi-chip LED light source). In this case, the light intensity is sufficient. However, it is expected that the light emission pattern of the LED light source is easily projected and it is difficult to perform uniform illumination. In particular, in the case of an LED light source for a lamp, there is no problem if it is simply used to illuminate a room or the like. However, when used as inspection illumination, a light emission pattern is likely to be projected onto an inspection object and uniform illuminance is obtained. There is a problem that accurate inspection or determination becomes difficult due to the fact that it cannot be obtained.

  Therefore, the present invention solves the above-described problems, and an object of the present invention is to provide an illuminating device that can obtain a sufficient illumination intensity and is difficult to project an LED light emission pattern.

In view of such circumstances, the illumination device of the present invention, Ri Na plurality of LED chips are arranged on the surface, the LED light source does not have a lens structure of each chip, concavely curved on the side facing the said LED light source A convex meniscus lens comprising a light curved surface on which the light incident surface and the light emitting surface are continuous, and a light curved surface on the opposite side of the LED light source. there, comprising a plurality of incident side lenses arranged in series, and a condenser lens arranged on the side opposite to the LED light source with respect to the incident-side lens, at least one of said plurality of incident side lenses The light incident surface of one incident side lens is a rough surface, and the light exit surface of the plurality of incident side lenses is a smooth surface, and is closest to the LED light source of the plurality of incident side lenses. Incident side lens The effective diameter is larger than the circumscribed circle diameter of the light emitting region of the LED light source, and the effective diameter of the incident side lens on the opposite side to the LED light source between the adjacent incident side lenses is incident on the LED light source side. The effective diameter of the condensing lens is larger than the effective diameter of the incident side lens farthest from the LED light source among the plurality of incident side lenses and is adjacent to each other. The divergent light beam emitted from within the effective diameter of the incident side lens on the LED light source side is incident within the effective diameter of the incident side lens opposite to the LED light source, and among the plurality of incident side lenses The divergent light beam emitted from the effective diameter of the incident side lens farthest from the LED light source is incident on the effective diameter of the condenser lens (22) .

According to the present invention, the light emitted from the LED light source is scattered when passing through the incident side lens because at least one of the light incident surfaces of the plurality of incident side lenses is a rough surface, and then the incident side lens. The light emitted from the light exit surface is emitted after being collected by the condenser lens. Here, since the light incident surface of the incident side lens has a concave curved surface shape, it is easy to secure the distance between the LED light source and the light incident surface while suppressing the distance in the optical axis direction of the illumination device. Emission light from the light source can be captured in a wide angle range, and the incident lens has a rough optical surface that can be scattered near the LED light source, ensuring illumination light emission efficiency. In addition, the uniformity of the illuminance distribution can be obtained. In addition, since the incident side lens has a concave curved light incident surface, the degree of light collection is limited. However, by using a plurality of incident side lenses and separately providing a condensing lens, the light condensing performance can be improved. The required illuminance can be easily obtained. Furthermore, since the light is scattered by the rough surface of the incident side lens and then condensed by the condensing lens, it is possible to suppress a decrease in efficiency when the illumination light is emitted.

In the present invention, a the light incident surface is rough surface of the entrance side lens, by the light emitting surface is a smooth surface, in addition to the above effects, in concavely curved light incident surface of the incident-side lens Since the emitted light can be scattered, it can be scattered at a location closer to the LED light source, and the light exit surface is a convex curved surface, so that the scattered light can be efficiently condensed to the condenser lens. Can be emitted. Therefore, it is possible to obtain a sufficient scattering effect and more uniform illumination, and at the same time, it is possible to efficiently collect the light on the irradiation target, thereby increasing the illuminance.

In the present invention, the plurality of incident side lenses are arranged in series, the light incident surface of the incident side lens closest to the LED light source is a rough surface, and the other optical surfaces of the plurality of incident side lenses are smooth. A surface is preferred. According to this , not only can the illumination efficiency be further increased by using a plurality of incident side lenses as described above , but the nearest light incident surface is a rough surface and the other optical surfaces are smooth surfaces. As a result, it is possible to achieve both the efficient use of light and uniform illumination distribution at a higher level.

  In the present invention, a photodetector arranged around the LED light source and at a position facing the light incident surface of the incident side lens, and the LED light source based on the light amount detected by the photodetector. It is preferable to further comprise a control driving means for controlling and driving. According to this, the light emission amount of the LED light source can be measured with high accuracy and stability by the light scattered on the rough surface.

  According to the present invention, it is possible to provide an excellent effect that a sufficient illumination intensity can be efficiently obtained and a lighting device capable of realizing a uniform illuminance distribution can be provided.

The disassembled perspective view of the illuminating device of embodiment which concerns on this invention. The perspective view which shows the state which looked at the illuminating device of the embodiment from diagonally forward. The perspective view which shows the state which looked at the main body of the illuminating device of the embodiment from diagonally backward. The longitudinal cross-sectional view of the illuminating device of the embodiment. The front view of the LED light source vicinity of the embodiment. Sectional drawing (a) of the LED light source vicinity of the embodiment and typical sectional drawing of an LED light source. FIG. 2 is a schematic configuration diagram of an optical system according to the embodiment. The schematic block diagram which shows the light-scattering state by the incident side lens by the side of the LED light source of the embodiment. The photograph which shows the illuminance distribution at the time of using the plano-convex lens provided with the smooth light-incidence surface for the incident side lens (comparative example 1). The photograph which shows illuminance distribution at the time of using the meniscus lens provided with the smooth light-incidence surface for the incident side lens (comparative example 2). The photograph which shows the illuminance distribution at the time of using the plano-convex lens provided with the light-incidence surface roughened to the incident side lens (comparative example 3). The photograph which shows the illumination intensity distribution at the time of using the meniscus lens roughened for the incident side lens (Example).

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of an embodiment of a lighting device according to the present invention, FIG. 2 is an external perspective view of the embodiment viewed obliquely from the front, and FIG. 3 is a perspective view of the main body of the embodiment viewed obliquely from the rear. FIG. 4 is a longitudinal sectional view of the main body of the embodiment. Note that the illumination device of the present embodiment is also suitable as a medical or dental illumination device in addition to the optical member inspection illumination device.

  As shown in FIG. 2, the lighting device 10 includes a cylindrical main body 10A and a holder 10B for supporting or attaching the main body 10A at an appropriate place. The main body 10A is formed in a cylindrical barrel shape in the illustrated example. The main body 10 </ b> A includes a main case portion (main body housing) 11 having an accommodation space therein, and a rear plate 12 that closes the rear opening of the main case portion 11. Further, an illumination case part 13 is attached to the front part of the main case part 11, and an emission case part 14 is attached to the front part of the illumination case part 13. The main case portion 11 and the illumination case portion 13 are configured to be detachable with a screw structure or the like, and the illumination case portion 13 and the emission case portion 14 are also configured to be detachable with a screw structure or the like.

  As shown in FIG. 1, a plate-like support portion 11a is provided at the front portion of the main case portion 11, and a cylindrical peripheral frame 11b protruding forward is provided around the support portion 11a. An outer peripheral surface of the peripheral frame 11b A male screw portion that is screwed onto the illumination case portion 13 is formed on the top. An LED light source 15 is attached on the outer surface of the support portion 11a. A circuit board 16 is accommodated in the main case portion 11. The circuit board 16 is provided with a control drive circuit 16a including a light source control circuit for controlling the LED light source 15 and a light source drive circuit. Further, the circuit board 16 is provided with a protruding portion that protrudes forward, and a photodetector 17 is mounted at the tip of the protruding portion. The photodetector 17 is disposed at a position exposed to the front of the support portion 11a through an opening 11c provided in the support portion 11a. Further, the LED light source 15 is connected to a wiring 16b connected to the circuit board 16 through another opening 11d provided in the support portion 11a.

  The circuit board 16 is attached to the rear plate 12, and as shown in FIG. 3, the power switch 18A and the light amount setting switch 18B mounted on the rear portion of the circuit board 16 are exposed rearward through a plurality of openings of the rear plate 12. Yes. On the rear plate 12, a power connector 19A for connecting a power cord 19B is also provided. Further, the wiring 16b connected to the external power switch 18C (see FIG. 2) through the opening of the rear plate 12 is led out.

  The light source control circuit of the control drive circuit 16a detects the amount of light emitted from the LED light source 15 based on the detection signal of the photodetector 17, and controls the LED light source 15 for the light source drive circuit according to the detected amount of emitted light. Output a signal. The light source driving circuit determines the driving mode of the LED light source 15 based on the control signal. For example, if the light source driving circuit is a constant current circuit, the current value of the constant current circuit is set.

  An incident side lens barrel 21 is disposed in front of the LED light source 15. The incident side lens barrel 21 is fitted inside the peripheral frame 11 b of the main case portion 11. As shown in FIG. 4, incident side lenses 21 </ b> A and 21 </ b> B, which are convex meniscus lenses, are held in series inside the incident side lens barrel 21. A condensing lens 22, which is a biconvex lens held by the exit case portion 14 via the illumination case portion 13, is disposed in front of the incident side lens barrel 21.

  The main case portion 11 and the lighting case portion 13 are both made of a material having a high heat transfer property such as a metal such as aluminum (alloy), and uneven radiating fins 11f and 13f are integrally formed on the outer peripheral surface thereof. Is provided. Similarly, the rear plate 12 and the emission case portion 14 are preferably made of metal. This is because the heat generated in the LED light source 15 is efficiently dissipated after being transmitted from the support portion 11a to the outer peripheral portion.

  In order to reduce stray light inside the main body 10A, at least the outer surface of the support portion 11a of the main case portion 11, the inner surface of the peripheral frame 11b, the inner and outer surfaces of the incident side lens barrel 21, and the inner surface of the illumination case portion 13 Further, the inner surface of the emission case portion 14 is a surface that is subjected to an antireflection treatment such as a black alumite treatment or a matte black paint such as a black acrylic resin coating to suppress light reflection. In the present embodiment, the antireflection treatment is applied to the entire surface of the main case portion 11, the rear plate 12, the illumination case portion 13, and the emission case portion 14.

  As shown in FIG. 4, in the present embodiment, the effective diameter of the incident side lens 21 </ b> A (the diameter of the area through which the light beam emitted from the LED light source 15 can pass freely, rather than the diameter of the light emission range of the LED light source 15). The same applies hereinafter), and the effective diameter of the incident side lens 21B disposed on the opposite side of the LED light source 15 is larger than the effective diameter of the incident side lens 21A, and further, the effective diameter of the incident side lens 21B. The effective diameter of the condenser lens 22 is configured to be large. The illumination case part 13 has an inner surface 13 a that gradually increases in diameter from the front part of the incident side lens barrel 21 toward the condenser lens 22. In the case of the illustrated example, the inner surface 13a is formed in a conical surface shape that spreads forward.

  More specifically, the inner surface 13a is configured not to block a light beam traveling from the effective diameter of the incident side lenses 21A and 21B to the effective diameter of the condensing lens 22. That is, as shown in FIG. 7, the inner surface 13a extends from a circle indicating the effective diameter of the incident side lens 21B to a circle indicating the effective diameter of the condenser lens 22, or along the outer side of the conical surface. It has a conical surface. For this reason, at least a part of stray light other than the light beam that has passed through the effective diameter collected by the incident side lenses 21A and 21B is blocked by the inner surface 13a.

  In addition, a light shielding surface 14 a that protrudes forward from the periphery of the condenser lens 22 is provided inside the emission case portion 14. In the illustrated example, the light shielding surface 14 a is a cylindrical surface parallel to the optical axis 20. However, the light shielding surface 14a is not particularly limited as long as it can block at least a part of stray light other than the luminous flux that has passed through the effective diameter from the incident side lenses 21A and 21B toward the condenser lens 22. In this case, it is more desirable that the light shielding surface 14a is configured to allow all of the light beams emitted from the condenser lens 22 to pass through the effective diameter.

  5 is an enlarged partial plan view showing an enlarged structure on the support portion 11a of the main case portion 11, FIG. 6A is an enlarged sectional view showing the structure, and FIG. It is an expanded sectional view.

  An LED light source 15 is closely fixed on the support portion 11a. The LED light source 15 includes a substrate 151 made of aluminum, an aluminum alloy, or the like, and wiring layers 153A and 153B formed in a predetermined pattern on the substrate 151 via an insulating film 152. An LED chip 155 is formed on the substrate 151 with an insulating layer 154 interposed therebetween. On the substrate 151, a plurality of LED chips 155 are arranged in the region 15A. These LED chips 155 are conductively connected to adjacent wiring portions of the wiring layers 153A and 153B through conductive members such as gold wires 156A and 156B. In the illustrated example, all of the plurality of LED chips 155 are connected in parallel between the wiring layers 153A and 153B.

  The wiring layers 153A and 153B are connected to the control drive circuit 16a through the wiring 16b. When the light source control circuit in the light source control circuit 16a outputs a predetermined control signal according to the detection signal of the photodetector 17, the light source driving circuit responds to the control signal with the wiring layers 153A and 153B of the LED light source 15 being used. A predetermined electric power (current) is supplied during

  A translucent resin layer 157 made of a transparent resin in which a fluorescent material such as YAG is dispersed is formed in a range including the region 15A in which a plurality of LED chips 155 are arranged. The translucent resin layer 157 realizes illumination characteristics (wavelength dependence and emission angle dependence of outgoing light intensity) required as illumination light of the lighting device according to the light emission characteristics of the LED chip 155.

  Note that the LED light source 15 used in the present embodiment is a white diode using the above-described fluorescent material, but various phosphor methods, for example, as long as various illumination characteristics required as illumination light can be obtained. It is not limited to the above-mentioned form, such as a three-color LED system. For example, it may be whitened by providing a yellow filter in the optical system, or may be a multi-color LED arrayed without resin sealing. In some cases, the life of the light source can be extended by not sealing with resin.

In addition, the LED light source 15 of the present embodiment realizes high luminance by arranging a large number of LED chips in a small area at a high density, but a plurality of LED chips are arranged on the installation surface (planar in the illustrated example). As long as it is arranged in the above, the number and brightness of the LED chips are not limited at all. However, from the viewpoint of obtaining luminance necessary for the LED light source 15, the arrangement density of the LED chips 155 is preferably 10 / cm ² or more, and more preferably 50 / cm ² or more. Generally, the arrangement density is preferably in the range of 50 to 150 / cm ² . The planar size of a single LED chip 155 is generally about 0.2 to 2.0 mm square. The LED chip 155 of the present embodiment is composed of a semiconductor chip itself, but the LED light source 15 is a surface-mount package LED (about 0.6 to 7.0 mm square) encapsulating the semiconductor chip as a substrate. The structure mounted above may be used. The surface of the LED light source 15 (the surface of the substrate 151, that is, at least the surface portion other than the light emitting element in the region 15A) is a reflecting surface, and emits light emitted from the LED chip 155 or incident light from the incident lens 21A side. Configured to reflect.

  FIG. 7 is a diagram showing the overall configuration of the optical system of the present embodiment. Light is emitted in a relatively wide range from the light emitting region 15a of the LED light source 15 (a plane substantially corresponding to the region 15A). This emission angle range (for example, an angle range in which the light intensity is half the light intensity in the direction with the highest light intensity (on the optical axis 20), that is, a half-value angle) is about 110 to 120 degrees centered on the optical axis 20. The range of the degree. It should be noted that, by appropriately setting the effective diameter of the incident side lens 21A and the distance from the LED light source 15, it is configured so that all the light within the above emission angle range passes through the effective diameter of the incident side lens 21A. Is preferred. In the illustrated example, it is configured such that light within an emission angle range of 140 degrees can pass through the effective diameter of the optical system.

  The emitted light is first incident on the incident side lens 21A. The incident side lens 21A is a meniscus lens, and its light incident surface 21a-1 has a concave curved surface (in the illustrated example, a concave spherical surface, the same applies hereinafter), and the light emitting surface 21a-2 has a convex curved surface (in the illustrated example, convex). Spherical surface, and so on.) Since the light incident surface 21a-1 has a concave curved surface, the light emitted from the LED light source 15 having a wide emission angle as described above can be efficiently incident on the incident side lens 21A. Further, since the incident side lens 21A is a convex meniscus lens having a larger curvature on the light exit surface 21a-2 than on the light incident surface 21a-1, it has a light collecting ability and is incident in a wide range. The emitted light can be converged in a smaller angle range.

  The effective diameter 21ar of the incident side lens 21A is set to be larger than the outer diameter 15r of the light emitting region 15a (diameter when a circle passing through the outermost portion centered on the optical axis 20 is drawn). The light emitting region 15a is located closer to the incident side lens 21A (21B) along the optical axis 20 than the center of curvature of the light incident surface 21a-1 (21b-1) of the incident side lens 21A (and 21B). Placed in position. Thereby, it can be configured such that emitted light in a wider angular range can be incident on the incident side lens 21A (21B). Further, even if the emission light in such a wide angle range can be incident on the incident side lens 21A, the light incident surface 21a-1 is formed in a concave curved surface, so that light emission on the optical axis 20 is achieved. Since the distance between the region 15a and the incident side lens 21A can be ensured, the light emitted from the LED light source 15 can be sufficiently diffused by reflection by the substrate 151 together with a scattering effect by a rough surface described later.

  In the present embodiment, it is preferable that all the light in the emission angle range emitted from the outer diameter 15r is incident on the optical system. In this case, even if the light emitting region 15a is not circular as in the illustrated example, the outer diameter 15r is not an inscribed circle of the light emitting region 15a but a circumscribed circle (a circle passing through the outermost point (corner) in the radial direction). ) Is desirable. This is because light emitted from the LED light source 15 can be used as illumination light with maximum efficiency (light use efficiency can be increased). Further, in this way, the light reflecting the light emission pattern of the light emitting region 15a is directly taken into the optical system, but the influence of the light emission pattern shape of the light emitting region 15a on the illumination distribution is uniform in the illuminance distribution by the rough surface. The problem does not occur.

  The light that has passed through the incident side lens 21A then passes through the incident side lens 21B. The incident side lens 21B is a meniscus lens, the light incident surface 21b-1 has a concave curved surface shape, and the light emitting surface 21b-2 has a convex curved surface shape. The incident side lens 21B is also a convex meniscus lens having a larger curvature on the light exit surface 21b-2 than on the light incident surface 21b-1, and thus has a light collecting ability and is incident in a wide range. The emitted light can be converged in a smaller angle range. The effective diameter 21br of the incident side lens 21B is set larger than the effective diameter 21ar of the incident side lens 21A. Thereby, even if the light condensing property of the incident side lens 21A is low, it can be configured such that outgoing light in a wider angle range from the incident side lens 21A can be incident on the incident side lens 21B, thereby improving the light utilization efficiency. it can.

  The curvature of the light incident surface 21b-1 is smaller than the curvature of the light incident surface 21a-1. This is because the exit angle of the emitted light from the incident side lens 21A is smaller than the incident angle of the emitted light of the LED light source 15 due to the light condensing property of the incident side lens 21A, and thus the light passes through the effective diameter of the incident side lens 21A. This is because the curvature required to capture all the light is reduced. In addition, since the curvature of the light incident surface 21b-1 is thus reduced, it is easy to improve the light condensing property of the incident side lens 21B. Here, it is preferable that all the light that has passed through the effective diameter of the incident side lens 21A pass through the effective diameter of the incident side lens 21B. It is desirable to configure so as to pass through the effective diameters of 21A and 21B.

In the present embodiment, the two incident side lenses 21A and 21B are arranged in series, but three or more incident side lenses may be arranged in series. The configuration of these lens groups is determined by the relationship between the light emission brightness of the LED light source 15 and the size of the light emitting region 15a, the illuminance required during inspection, and the illumination range, for example, when the illumination device 10 is used as inspection illumination. It is done.

  A condensing lens 22 is disposed in front of the incident side lenses 21A and 21B. Although the condensing lens 22 will not be specifically limited if it has condensing property, In this embodiment, all of the light-incidence surfaces 22a and 22b are biconvex lenses with a convex-curve shape. Thereby, sufficient light collecting performance can be obtained. In addition, the condensing lens should just be an optical system which has condensing property, and can comprise either a single lens and the lens group containing a some lens. The effective diameter 22r of the condensing lens 22 is larger than the effective diameter 21br of the incident side lens 21B. Thereby, even if the condensing property of entrance side lenses 21A and 21B is low, the fall of the utilization efficiency of light can be suppressed. In the present embodiment, all of the light emitted from the effective diameter of the incident side lens 21 </ b> B passes through the effective diameter of the condenser lens 22.

  In the above optical system, at least one of the optical surfaces of the incident side lenses 21A and 21B is a rough surface. FIG. 8 shows an example in which the light incident surface 21a-1 of the incident side lens 21A is a rough surface and the other optical surfaces are smooth surfaces. In this case, the light emitted from the LED light source 15 is scattered on the light incident surface 21a-1 which is the first optical surface, and the inner surface (the support portion 11a, the inner surface of the peripheral frame 11b, the illumination) of the scattered light. What is not absorbed by the inner surface of the case 13), for example, light that is directly scattered in the incident side lens 21A or light that is reflected by the LED light source 15 toward the incident side lens 21A is incident on the incident side lens 21B. Finally, the light is condensed by the condenser lens 22 and emitted.

  The rough surface can be formed by polishing an incident side lens made of a glass substrate with, for example, an abrasive having a particle size of # 1000 (JIS R6001), and a frost etching process using a frost agent. It can also be formed. In addition, when forming the incident side lens by resin molding, it is also possible to form the rough surface by making the mold surface rough.

  By making the optical surfaces of the incident side lenses 21A and 21B rough as described above, the light emission pattern shape of the light emitting surface 15a of the LED light source 15 is projected even when the emitted light of the LED light source 15 is condensed and irradiated. Can be prevented, and uniform and high illuminance can be realized. Such an illumination mode is extremely effective when inspecting scratches, dust, burns, bubbles, and other dirt on the optical lens. For example, when performing the above-mentioned inspection visually, although the inspection is performed by unifying the judgment criteria by performing the operation of `` matching '', if there is a magnitude or variation of the illumination device illumination, projection of the light emission pattern, etc., An accurate inspection cannot be performed. Even in the case where an inspection is performed based on an image obtained by photographing an illuminated optical lens, if the illumination condition varies or a light emission pattern is projected, the inspection accuracy also decreases in the determination by image processing.

  In this embodiment, in particular, by making the light incident surface 21a-1 of the first incident side lens 21A rough, it is possible to obtain a sufficient light diffusion effect by scattering light near the LED light source 15. At the same time, since the light exit surface 21a-2 of the incident lens 21A, the incident lens 21B, and the condensing lens 22 condense, it is possible to perform uniform illumination with high illuminance. .

  In particular, in the present embodiment, light emitted from the high-intensity LED light source 15 (in the illustrated example, the LED chip 155 made of a blue light-emitting diode) is used, so that an incandescent bulb, a fluorescent lamp, a halogen lamp, etc. Compared with other light sources, it has a wavelength distribution in which the light intensity in the short wavelength region is high. Specifically, the wavelength distribution has a peak intensity at a wavelength of 450 nm (this intensity is assumed to be 100%) and a broader peak (intensity of 66%) at a wavelength of 560 nm. For this reason, it has the characteristic that the scattering intensity by a rough surface also becomes high. Further, as will be described later, the light emitted from the LED chip 155 is not interposed through a condensing element such as a resin lens (via the light-transmitting resin layer 157 in which the fluorescent material is dispersed as necessary). A high degree of scattering can be realized by directly scatter on a rough surface.

  Further, in this embodiment, since the LED light source 15 in which a plurality of LED chips 155 are arranged on the surface at a high density is used, a resin lens or the like cannot be provided for each LED chip 155, and the chip actually Does not have a lens structure. As a result, the light emission pattern has a special shape based on the array pattern of the LED chips 155, and the viewing angle (emission angle range) of the light emitted from the LED light source 15 is as extremely wide as about 110 to 120 degrees. It has become. Therefore, there is a possibility that uneven illumination may be caused by projecting the light emission pattern shape as it is, and high illuminance cannot be obtained unless the light emitted to the wide range is efficiently condensed.

  In the present embodiment, by arranging the incident side lens 21A having the concave curved light incident surface 21a-1 adjacent to the LED light source 15, the emitted light emitted from the LED light source in a wide angle range is effectively captured. In addition, the light can be condensed and emitted by the light emitting surface 21a-2 having a convex curved surface. Therefore, it is possible to efficiently capture and efficiently collect the emitted light of the LED light source 15 having a wide emission angle range.

  Further, in the present embodiment, another incident side lens 21B is provided, and the incident side lens 21B is also provided with a concave curved light incident surface 21b-1 on the side of the LED light source 15, so that the incident side lens 21A is separated from the incident side lens 21A. The emitted light can be captured in a wide range, and can be condensed and emitted by the convex light emitting surface 21b-2. Therefore, the light emitted from the LED light source 15 can be efficiently captured and condensed with a compact optical system.

In this embodiment, since the condensing lens 22 is further arranged on the opposite side of the LED light source 15 with respect to the incident side lenses 21A and 21B, the light emitted from the incident side lenses 21A and 21B is further condensed. Therefore, high illuminance suitable for the inspection process can be realized. The condensing lens 22 is not limited to the biconvex lens as shown in the figure, but may be any lens such as a plano-convex lens or a convex meniscus lens as long as it exhibits condensing characteristics .

  In the present embodiment, by making any one of the optical surfaces of the incident side lenses 21A and 21B rough, the light emitted from the LED light source 15 is scattered before final condensing by the condensing lens 22, so that the LED The light emission pattern of the light source 15 can be eliminated. As a result, even if light emitted from the LED light source 15 is condensed to achieve high illuminance, the light emission pattern of the LED light source 15 does not form an image. Therefore, the illuminance caused by the harmful light emission pattern in the inspection process is eliminated. Variation and wavelength dispersion can be prevented.

  In particular, in the present embodiment, the light incident surfaces 21a-1 and 21b-1 of the incident-side lenses 21A and 21B are roughened, so that the LED light source 15 is collected before the light condensing by the light emitting surfaces 21a-2 and 21b-2. Since the emitted light can be scattered, there is an advantage that it is difficult to prevent efficient light collection. This advantage is that the light incident surface 21a-1 of the incident side lens 21A adjacent to (closest to) the LED light source 15 is made rough when using a plurality of incident side lenses 21A and 21B as in the present embodiment. Is further enhanced by.

  In the present embodiment, the concave light-incident surfaces 21a-1 and 21b-1 of the incident-side lenses 21A and 21B formed as rough surfaces face the LED light source 15 side, so that the LED light source 15 Since the scattered light traveling toward the side of the light source is less likely to be scattered outside (the side away from the optical axis 20), such scattered light is reflected at the LED light source 15 or its surroundings and returns to the incident side lenses 21A and 21B again. Therefore, it can be used as an illumination component, so that more efficient illumination can be realized. This advantage is also achieved by making the light incident surface 21a-1 of the incident side lens 21A adjacent to (closest to) the LED light source 15 rough when using a plurality of incident side lenses 21A and 21B as in this embodiment. Is further enhanced by.

  In the present embodiment, the amount of light emitted from the LED light source 15 is detected by the photodetector 17 disposed around the LED light source 15 as described above. In this case, since the concave light-incident surface 21a-1 is a rough surface, scattered light obtained by scattering light from the LED light source 15 on the light incident surface 21a-1 is mainly detected by the photodetector 17. Since the amount of light detected by the photodetector 17 is less likely to be affected by variations among the plurality of LED chips 155 in the LED light source 15 and differences with time, the detection light amount can be increased in accuracy. Stabilization can be achieved. This advantage is also achieved by making the light incident surface 21a-1 of the incident side lens 21A adjacent to (closest to) the LED light source 15 rough when using a plurality of incident side lenses 21A and 21B as in this embodiment. This further enhances the amount of light detected.

  9 to 12 show photographs showing illumination modes of the example and the comparative example. Here, each lens of the example having the configuration of the present embodiment uses a spherical lens of optical glass BK7, and for each optical surface, the light emitting surface of the light emitting region 15a of the LED light source 15 (the aperture 9 as the effective diameter). .000 mm) or the distance on the optical axis 20 from the adjacent optical surface and the radius of curvature are as follows. In the incident lens 21A having a diameter of 23.000 mm, the distance between the light incident surface 21a-1 and the light emitting surface is 6.000 mm, the radius of curvature of the light incident surface 21a-1 is -15.000 mm, and the light emitting surface 21a-2. In the incident lens 21B having a distance of 5.000 mm from the light incident surface 21a-1, a radius of curvature of the light emitting surface 21a-2 of -12.000 mm, and a diameter of 32.000 mm, the light incident surface 21b-1 and the light emitting surface The distance from the surface 21a-2 is 1.000 mm, the radius of curvature of the light incident surface 21b-1 is −40.000 mm, the distance between the light emitting surface 12b-2 and the light incident surface 21b-1 is 9.000 mm, and light In the condensing lens 22 whose exit surface 21b-1 has a radius of curvature of -17.000 mm and an aperture of 50.000 mm, the distance between the light incident surface 22a and the light exit surface 21b-2 is 8.950 mm, Radius of curvature 81.130mm of the entrance surface 22a, the distance between the light emitting surface 22b and the light incident surface 22a is 11.000Mm, the curvature of the light exit surface 22b with a radius of -81.313Mm. The focal length of this optical system was set to 1000.000 mm.

  On the other hand, the case where an incident side lens of a plano-convex lens in which the light incident surface 21a-1 of the above embodiment is changed to a flat smooth surface is used as Comparative Example 1, and the light incident surface 21a-1 of the embodiment is a concave curved surface. The case where the surface is changed to a smooth surface is referred to as Comparative Example 2, and the case where a plano-convex lens is used in which the light incident surface 21a-1 of the embodiment is a rough surface but is changed to a flat surface is used as Comparative Example 3, respectively. The illuminance and illuminance distribution were examined with examples. Other optical surfaces are the same as in the embodiment. Here, FIG. 9 is a photograph of Comparative Example 1, FIG. 10 is a Comparative Example 2, FIG. 11 is a photograph of the illumination pattern of the Example, and FIG. 12 is a photograph of the illumination pattern of the Example. The illumination spot irradiated to the to-be-illuminated board (metal plate) painted in gray was image | photographed in the dark room. Note that the bright spot seen in the upper center of each photograph is a direct reflection of light from the illuminated plate.

  Table 1 below shows illuminance data obtained by measuring a portion with the highest illuminance at the distance from the front end of the device (the central portion of the illumination range) with an illuminometer, and uniformity of illuminance distribution (the degree of disappearance of the light emission pattern). The results of evaluating the degree of light and the light illumination efficiency in four stages are shown. For example, 80.00 kL in the table indicates 80,000 lux. In the remarks column, the mode of the optical surface of the light incident surface 21a-1 (concave or flat, smooth or rough) is shown.

  As a result, as shown in FIGS. 9 to 12, the light emission pattern disappeared completely in the example (FIG. 12), whereas all of Comparative Examples 1 to 3 (FIGS. 9 to 11). The light emission pattern remains, and in Comparative Examples 1 and 2, the shape of the light emission pattern is clearly reflected. In the example and comparative examples 1 and 2, the total luminous flux of the illumination is high, whereas in the comparative example 3, the illuminance is lowered and the luminous flux is reduced. Note that the illuminance data at the center of the embodiment is lower than that in Comparative Examples 1 and 2, but this is because the illumination range is wide and the illuminance distribution is uniform. The illuminance or light efficiency (the intensity of the total luminous flux irradiated to the illumination range, or the light use efficiency or ratio when obtaining the illumination light from the emitted light of the LED light source) of the example is higher than that of Comparative Example 1 and Comparative Example 2 It is equally good.

  In addition, the illuminating device of this invention is not limited only to the above-mentioned illustration example, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 10 ... Illuminating device, 10A ... Main body, 10B ... Holder, 11 ... Main case part, 12 ... Rear plate, 13 ... Illuminating case part, 14 ... Outgoing case part, 11a ... Supporting part, 11b ... Surrounding frame, 15 ... LED Light source, 155 ... LED chip, 15a ... light emitting area, 16 ... circuit board, 16a ... control drive circuit, 17 ... photodetector, 20 ... optical axis, 21 ... incident side lens barrel, 21A, 21B ... incident side lens, 22 ... Condensing lens

Claims (4)

Ri Na plurality of LED chips (155) is arranged on a surface, the LED light source does not have a lens structure of each chip (15),
A light incident surface (21a-1, 21b-1) having a concave curved surface is provided on the side facing the LED light source and a light emitting surface (21a-2, 21b-2 ) having a convex curved surface on the side opposite to the LED light source. ) equipped with the light incident surface and the light exit surface is a convex meniscus lens formed by respective successive one of the curved surfaces, and a plurality of incident side lenses arranged in series (21A, 21B),
A condenser lens (22) disposed on the opposite side of the LED light source with respect to the incident side lens;
The light incident surface (21a-1) of at least one incident side lens (21A) of the plurality of incident side lenses is a rough surface, and the light emission of the plurality of incident side lenses (21A, 21B). The surfaces (21a-2, 21b-2) are smooth surfaces,
The effective diameter (21ar) of the incident side lens (21A) closest to the LED light source among the plurality of incident side lenses is larger than the circumscribed circle diameter (15r) of the light emitting region (15a) of the LED light source. The effective diameter (21br) of the incident side lens (21B) on the opposite side of the LED light source between the incident side lenses adjacent to each other is larger than the effective diameter (21ar) of the incident side lens (21A) on the LED light source side. The effective diameter (22r) of the condenser lens is larger than the effective diameter (21br) of the incident side lens (21B) farthest from the LED light source among the plurality of incident side lenses,
The divergent light beam emitted from the effective diameter of the incident side lens (21A) on the LED light source side between the adjacent incident side lenses is within the effective diameter of the incident side lens (21B) opposite to the LED light source. A divergent light beam that enters and exits from the effective diameter (21br) of the incident side lens (21B) farthest from the LED light source among the plurality of incident side lenses is the effective diameter (22r) of the condenser lens (22). The illumination device is incident on the inside of the illumination device. Is the rough surface light incident surface (21a-1) of the nearest the incident side lens to the LED light source (21A) of said plurality of incident side lenses, other incident side of the plurality of incident side lenses lighting apparatus of claim 1 wherein the light incident surface (21b-1) is characterized by smooth surface der Rukoto lens (21B). A case body (11, 13, 14) for housing the LED light source, the incident side lens and the condenser lens;
The case body is provided with an inner surface (13a) that is formed of a surface that is subjected to antireflection treatment and light reflection is suppressed and that gradually increases in diameter from the incident side lens toward the condenser lens. A light beam which is configured so as not to be shielded from an effective diameter of a plurality of incident side lenses and into an effective diameter of the condenser lens and which has passed through an effective diameter of the plurality of incident side lenses (21A, 21B). the lighting device according to claim 1 or 2, wherein at least a portion of the stray light, characterized in that it is blocked by the inner surface (13a) other than. The case body includes a main case portion (11) that holds the LED light source, an illumination case portion (13), and an emission case portion (14) that holds the condenser lens. 11) the lighting case part (13) is attached to the front part, and the light emitting case part (14) is attached to the front part of the lighting case part,
A plate-like support part (11a) for supporting the LED light source is provided on the front surface of the main case part (11), and a peripheral frame (11b) protruding forward is provided around the support part (11a). , on the inner side of the peripheral frame (11b), according to claim 3, wherein the plurality of incident side lenses (21A, 21B) incident lens barrel for holding the (21) is fitted Lighting device.