JP2012014853A - Led lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED lighting device capable of preventing leaked light to the outside of a designated irradiation range and lighting a designated irradiation range at uniform luminance.SOLUTION: The LED lighting device includes an LED 26, a reflective tube 6 for reflecting light emitted from the LED 26, an imaging lens 8 arranged in front of the reflective tube 6, and an aperture 10 arranged between the reflective tube 6 and the imaging lens 8 and having a limited opening 40. A reflecting surface 32 is formed inside the reflective tube 6, the reflecting surface 32 is extended by expanding from an incident side opening 28 of the reflective tube 6 to an emitting side opening 30 thereof, and the incident side opening 28 of the reflective tube 6 is arranged so as to cover a circumference of the LED 26. Direct light from the LED 26 and a luminous flux of reflected light with the reflective tube 6 are limited with the limited opening 40 of the aperture 10, and the limited light flux is imaged on an irradiation surface 42 with the imaging lens 8.

Description

  The present invention relates to an LED illumination device for illuminating a predetermined irradiation range using an LED as a light source.

  Conventionally, LED lighting devices for illuminating a predetermined irradiation range using an LED as a light source have been put to practical use. As such an LED lighting device, for example, a reading light, a medical lighting device, an image processing inspection lighting device, and the like are known.

  The reading lamp is arranged behind the LED, a reflecting mirror for reflecting the light emitted from the LED, and arranged in front of the LED to collect the direct light emitted from the LED and the reflected light from the reflecting mirror. (For example, refer patent document 1). Such a reading light is installed in, for example, a passenger plane or a railway vehicle. The direct light emitted from the LED and the reflected light from the reflecting mirror are collected by a light collecting plate, and the collected light illuminates a book, newspaper, etc. at hand of the user.

  Further, the medical lighting device includes an LED, a reflecting mirror that is disposed behind the LED and reflects light emitted from the LED, and a shielding plate that is disposed in front of the LED (for example, , See Patent Document 2). Such a medical lighting device is installed in the vicinity of, for example, a hospital examination table or a dental examination table in a dental clinic. The light emitted from the LED is reflected by the reflecting mirror, and the reflected light is irradiated forward to illuminate the affected area of the patient lying on the examination table, the dental examination table, or the like.

  Furthermore, the illumination device for image processing inspection includes a linear light source and a reflecting mirror having a cylindrical concave reflecting surface that reflects light emitted from the linear light source (see, for example, Patent Document 3). The linear light source is composed of a plurality of LEDs arranged in a straight line at intervals. Further, in the cross section orthogonal to the longitudinal direction of the linear light source, the concave reflecting surface of the reflecting mirror is composed of a part of an ellipse having the linear light source as one focal point and the irradiation point as the other focal point. Thereby, the light emitted from the linear light source is reflected by the concave reflecting surface of the reflecting mirror, and the workpiece is illuminated linearly by this reflected light.

JP 2009-202752 A Utility Model Registration No. 3084178 JP 2002-93227 A

  However, the conventional LED lighting device as described above has the following problems. First, there is a problem that the boundary between the predetermined irradiation range and the surrounding area is not clear, and the light emitted from the LED illuminates not only the predetermined irradiation range to be originally illuminated but also the surrounding area. For this reason, for example, in a reading light, there is a risk of light leaking to people around the user and the surrounding people may be dazzled, and in a medical lighting device, the eyes of a patient lying on an examination table, a dental examination table, etc. The patient may be dazzled by leaking light.

  Second, the illuminance distribution in the predetermined irradiation area is not uniform, and has a sinusoidal illuminance distribution in which the center of the predetermined irradiation area has a peak. There is a problem of end up. For this reason, in the illumination device for image processing inspection, optimal imaging data cannot be obtained when a predetermined irradiation area is imaged by the CCD camera. In addition, a method of correcting the imaging data so as to increase the brightness in the peripheral portion of the predetermined irradiation area after imaging by the CCD camera is conceivable. However, if such a method is adopted, the inspection process increases. This makes it impossible to perform inspection efficiently.

  The objective of this invention is providing the LED illuminating device which can illuminate a predetermined irradiation range with uniform illumination intensity while being able to prevent the light leakage outside a predetermined irradiation range.

In the LED lighting device according to claim 1 of the present invention, an LED, a reflecting tube for reflecting light emitted from the LED, an imaging lens provided in front of the reflecting tube, the reflecting tube, and the An aperture provided between the imaging lens and having a restricted opening,
A reflective surface is formed on the inner surface of the reflective cylinder, and the reflective surface extends from the incident side opening of the reflective cylinder toward the exit side opening, and the incident side opening of the reflective cylinder The part is arranged so as to cover the periphery of the LED,
The luminous flux of the direct light from the LED and the reflected light from the reflecting cylinder is limited by the limiting aperture of the aperture, and the limited luminous flux is imaged on the irradiation surface by the imaging lens. And

  In the LED illumination device according to claim 2 of the present invention, a field lens is provided between the aperture and the imaging lens.

  In the LED lighting device according to claim 3 of the present invention, a diffusion plate is provided between the LED and the aperture.

Moreover, in the LED lighting device according to claim 4 of the present invention, the LED is configured in a rectangular shape, and correspondingly, a cross section of the reflecting cylinder is configured in a rectangular shape, and the reflection of the reflecting cylinder is performed. The surface has a pair of first reflecting surfaces facing each other in a predetermined direction and a pair of second reflecting surfaces facing each other in a direction orthogonal to the predetermined direction,
The pair of first reflective surfaces are respectively disposed corresponding to the two opposite sides of the LED, and the pair of second reflective surfaces are disposed corresponding to the remaining two sides of the LED. It is provided.

  In the LED lighting device according to claim 5 of the present invention, an opening variable mechanism for changing the size of the limiting opening of the aperture is provided in association with the aperture. To do.

  According to the LED illumination device of the first aspect of the present invention, the narrow light distribution light including the optical axis among the light emitted from the LED is directly incident on the limiting opening of the aperture, and the light emitted from the LED Out of this, the light with a wide distribution toward the outside is incident on the aperture of the aperture after being reflected by the reflecting surface of the reflecting cylinder. Since the reflecting surface of the reflecting tube extends and extends from the incident side opening of the reflecting tube toward the exit side opening, the light with a wide light distribution emitted from the LED becomes a light with a narrow light distribution by the reflecting surface. After being converted, the light is emitted from the exit side opening of the reflecting cylinder, and the light converted into this narrow light distribution enters the limiting opening of the aperture. Thereby, all the light emitted from the LED is converted into a narrow light distribution, and enters the imaging lens after passing through the aperture of the aperture. As a result, the amount of light taken into the imaging lens can be increased, and the illumination efficiency can be increased. Further, the direct light emitted from the LED and the light beam reflected by the reflecting cylinder are limited by the aperture of the aperture. In the entire area of the restriction opening, the direct light directly incident on the restriction opening of the aperture from the LED overlaps with the reflected light incident on the restriction opening of the aperture after being reflected by the reflecting surface. Have a distribution. The light whose light flux is limited by the aperture is incident on the imaging lens, and is imaged on the irradiation surface by the imaging lens. The arrangement position of the aperture and the arrangement position of the irradiation surface are in an imaging relationship (conjugate relationship) with respect to the imaging lens, whereby an enlarged image of the aperture of the aperture is formed on the irradiation surface. Therefore, on the irradiation surface, similar to the light beam passing through the aperture opening of the aperture, the direct light directly incident on the aperture opening of the aperture from the LED and the light incident on the aperture opening of the aperture after being reflected by the reflecting surface. The reflected light is again superimposed on the irradiation surface, and an enlarged image of the aperture of the aperture having a uniform illuminance distribution is formed on the irradiation surface. Thereby, the illuminance distribution in the predetermined irradiation range can be a substantially uniform illuminance distribution having an irradiation range corresponding to the size of the enlarged image of the limited aperture of the imaged aperture. Further, no light leaks outside the aperture opening of the aperture, so no light leaks outside the predetermined irradiation range. As a result, the contour of the aperture of the aperture is clearly imaged on the irradiation surface, and the boundary between the predetermined irradiation range and its surroundings can be clearly and clearly illuminated.

  According to the LED illumination device of the second aspect of the present invention, since the field lens is provided between the aperture and the imaging lens, the light is emitted from the outside near the aperture of the aperture. Light is bent by the field lens in a direction approaching its optical axis and emitted from the field lens. As a result, the light incident near the outside of the imaging lens can be moved inward, so that the range of the light beam incident on the imaging lens can be narrowed. As a result, the size of the imaging lens can be reduced, and the entire LED illumination device can be reduced in size.

  Moreover, according to the LED lighting device of the third aspect of the present invention, since the diffusion plate is provided between the LED and the aperture, the direct light emitted from the LED and the reflected light from the reflecting tube are diffused respectively. The light that enters the plate and diffuses and exits from the diffuser plate is limited in its luminous flux by the limiting opening of the aperture. As a result, one surface (aperture-side surface) of the diffusion plate serves as a secondary surface light source, and an LED image is prevented from being formed between the imaging lens and the irradiation surface, and the irradiation distance (that is, the image formation). Even when the distance between the lens and the irradiation surface is short, the influence on the irradiation surface, such as an image of the LED wiring pattern reflected on the irradiation surface, can be reduced.

  According to the LED lighting device of the fourth aspect of the present invention, the cross sections of the LED and the reflecting tube are each formed in a rectangular shape, and the pair of first reflecting surfaces are two sides facing each other of the LED. And the pair of second reflecting surfaces are respectively arranged corresponding to the remaining two sides of the LED, so that the incident side opening of the reflecting tube is arranged so as to cover the periphery of the LED. It is easy to install. In general, since the chip constituting the LED is rectangular, when the light emitted from the LED is reflected by the reflecting cylinder, the cross section of the reflecting cylinder is configured to be rectangular so that the vicinity of the exit side opening of the reflecting cylinder Uniformity of illuminance is improved. In addition, when aiming at the power-up of light quantity by using several LED, it is preferable to arrange | position collectively several LED in a rectangular shape. In this way, most of the light emitted from the LED can be guided to the exit side opening of the reflecting tube without loss.

  Further, according to the LED illumination device of the fifth aspect of the present invention, since the aperture variable mechanism for varying the size of the aperture limiting aperture is provided, the aperture limiting aperture is controlled by the aperture variable mechanism. By changing the size of the portion, the size of the enlarged image of the aperture of the aperture that is imaged on the irradiation surface is changed. Thereby, according to the use etc. of a LED lighting apparatus, the magnitude | size of the predetermined irradiation range in an irradiation surface can be adjusted suitably. In addition, the aperture aperture has a uniform illuminance distribution, and the illuminance does not change even if the size of the aperture is changed. Does not change. In this way, even when the size of the predetermined irradiation range on the irradiation surface is appropriately adjusted, the illuminance can be kept constant and the convenience can be improved.

It is sectional drawing which shows the LED lighting apparatus by the 1st Embodiment of this invention. It is a perspective view which decomposes | disassembles and shows the light source of FIG. 1, a reflective cylinder, and an aperture. It is a figure for demonstrating the light distribution angle of the light emitted from LED of FIG. 1, and reflected with a reflective cylinder. It is a figure for demonstrating the illumination intensity distribution of the predetermined irradiation range by the LED illuminating device of FIG. (A) is a perspective view which shows the state which enlarged the opening width of the limiting opening part of the aperture by the LED illuminating device of the 2nd Embodiment of this invention, (b) is the opening width of the limiting opening part of an aperture It is a perspective view which shows the state which made small. It is a figure for demonstrating the illumination intensity distribution of the predetermined irradiation range by an LED illuminating device in the state which made the opening width | variety of the limiting opening part of an aperture small. It is a figure for demonstrating the illumination intensity distribution of the predetermined irradiation range by the LED lighting apparatus of the 3rd Embodiment of this invention. It is a figure for demonstrating the illumination intensity distribution of the predetermined irradiation range by the LED lighting apparatus of the 4th Embodiment of this invention.

Hereinafter, various embodiments of an LED lighting device according to the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
First, with reference to FIGS. 1-4, the LED illuminating device of 1st Embodiment is demonstrated. FIG. 1 is a cross-sectional view illustrating an LED lighting apparatus according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view illustrating a light source, a reflection cylinder, and an aperture of FIG. 1, and FIG. FIG. 4 is a diagram for explaining a light distribution angle of light emitted from the LED of FIG. 1 and reflected by a reflecting cylinder, and FIG. 4 is a diagram for explaining an illuminance distribution in a predetermined irradiation range by the LED illumination device of FIG. is there.

  With reference to FIGS. 1 and 2, the LED illumination device 2 of the present embodiment includes a light source 4, a reflection tube 6 for reflecting light emitted from the light source 4, and an image formed in front of the reflection tube 6. A lens 8 and an aperture 10 provided between the reflecting tube 6 and the imaging lens 8 are provided, and these are arranged in a casing 12.

  The casing 12 includes a first casing portion 14 in which the light source 4, the reflecting cylinder 6, and the aperture 10 are disposed, and a second casing portion 16 in which the imaging lens 8 is disposed. The 1st casing part 14 is formed in the rectangular box shape by which one end part was opened, and the screw hole 18 is provided in the outer surface. The second casing part 16 is formed in a rectangular cylindrical shape, and the second casing part 16 is provided with a guide hole 20 extending in the direction of the optical axis C. The second casing portion 16 is slidably attached to the outer surface of one end portion of the first casing portion 14. A heat radiating fin 21 is attached to the other end portion of the first casing portion 14 with a mounting screw 23.

  An adjustment screw 22 is screwed into the screw hole 18 of the first casing portion 14 through the guide hole 20 of the second casing portion 16. When the adjusting screw 22 is rotated in the tightening direction, the movement of the second casing portion 16 in the optical axis C direction with respect to the first casing portion 14 is prevented, and when the adjusting screw 22 is rotated in the loosening direction, Movement of the casing part 16 in the optical axis C direction with respect to the first casing part 14 is allowed. When the adjustment screw 22 is rotated in the loosening direction and the second casing portion 16 is moved in the direction indicated by the arrow P in FIG. 1 with respect to the first casing portion 14, the adjustment screw 22 extends along the guide hole 20. The imaging lens 8 is moved in a direction away from the aperture 10. Further, when the adjustment screw 22 is rotated in the loosening direction and the second casing portion 16 is moved in the direction indicated by the arrow Q in FIG. 1 with respect to the first casing portion 14, the adjustment screw 22 is inserted into the guide hole 20. The imaging lens 8 is moved in the direction approaching the aperture 10.

  The light source 4 includes a mounting board 24 and an LED 26 mounted on the mounting board 24. The LED 26 is a high-luminance type power LED, and its outer shape is formed in a rectangular shape. The light emitted from the LED 26 is distributed in a solid angle around the optical axis C, and most of the light is within a predetermined range of solid angle (ie, effective light distribution angle) around the optical axis C. Radiated. The mounting substrate 24 is attached to the inner side of the first casing portion 14. The mounting substrate 24, the first casing portion 14, and the heat radiating fins 21 are each formed of aluminum, and the heat of the LED 26 is radiated to the atmosphere via the mounting substrate 24, the first casing portion 14 and the radiating fins 21.

  The reflecting cylinder 6 is formed in a cylindrical shape having a rectangular cross section, and an incident side opening 28 is provided at one end of the reflecting cylinder 6 and an emission side opening 30 is provided at the other end. A reflecting surface 32 is formed on the inner surface of the reflecting cylinder 6, and the reflecting surface 32 faces a pair of first reflecting surfaces 34 facing each other in a predetermined direction and a direction orthogonal to the predetermined direction. And a pair of second reflecting surfaces 36. The first and second reflecting surfaces 34 and 36 are provided with specularity by applying metal vapor deposition, plating, polishing, or attaching a thin metal plate or tape having a specularity. The first and second reflecting surfaces 34 and 36 extend from the incident side opening 28 of the reflecting tube 6 toward the emission side opening 30 and extend.

  A rectangular support frame portion 38 is provided at one end of the reflection tube 6, and the aperture 10 is supported by the support frame portion 38, so that the aperture 10 covers the exit side opening 30 of the reflection tube 6. It is supported. The aperture 10 is provided with a rectangular limiting opening 40, and the opening width D 1 of the limiting opening 40 is configured to be equal to or smaller than the opening width D 2 of the exit side opening 30 of the reflecting tube 6. The central portion of the restriction opening 40 is positioned on the optical axis C. Note that the size and shape of the restriction opening 40 of the aperture 10 can be appropriately set according to the application of the LED lighting device 2 and the like.

  A mounting substrate 24 is attached to the other end of the reflecting cylinder 6. The incident side opening 28 has a shape corresponding to the outer shape of the LED 26, and is disposed so as to cover the periphery of the LED 26. The pair of first reflecting surfaces 34 are respectively disposed corresponding to the two opposite sides of the LED 26, and the pair of second reflecting surfaces 36 are respectively disposed corresponding to the remaining two sides of the LED 26. The

  The imaging lens 8 is composed of, for example, a Fresnel lens, and is attached to the opening of the second casing portion 16.

  Next, with reference to FIG.3 and FIG.4, the illumination by the LED lighting apparatus 2 of this embodiment is demonstrated. When the LED 26 is turned on, the light with a narrow light distribution including the optical axis C among the light emitted from the LED 26 is directly incident on the limiting opening 40 of the aperture 10. In addition, light emitted from the LED 26 and having a wide light distribution directed outward is reflected by the first and second reflecting surfaces 34 and 36 and then enters the limiting opening 40 of the aperture 10. Depending on the length of the reflecting tube 6 extending in the optical axis direction, the light with a wide light distribution emitted from the LED 26 may be reflected by the first and second reflecting surfaces 34 and 36 a plurality of times. The case where reflection is performed is shown. As described above, since the first and second reflecting surfaces 34 and 36 extend from the incident side opening 28 of the reflecting tube 6 toward the emission side opening 30, the first and second reflection surfaces 34 and 36 extend. The light distribution angle θ ′ of the light reflected by the surfaces 34 and 36 is smaller than the light distribution angle θ of the light emitted from the LED 26 (see FIG. 3). Thereby, the wide light distribution light emitted from the LED 26 is converted into narrow light distribution light by the first and second reflecting surfaces 34 and 36, and is emitted from the emission side opening 30.

  The light emitted from the exit side opening 30 of the reflecting cylinder 6 is limited in its luminous flux by the limiting opening 40 of the aperture 10. In the entire area of the limiting opening 40, direct light directly incident on the limiting opening 40 of the aperture 10 from the LED 26 and reflected by the first and second reflecting surfaces 34 and 36 and then entering the limiting opening 40 of the aperture 10. By overlapping the incident reflected light, a uniform illuminance distribution is obtained. The light whose luminous flux is limited by the aperture 10 enters the imaging lens 8. The luminous flux emitted from the imaging lens 8 is once focused on the image of the LED 26 at the focal point F (shown by a one-dot chain line in FIG. 3) and then focused on the irradiation surface 42. The arrangement position of the aperture 10 and the arrangement position of the irradiation surface 42 are in an imaging relationship (conjugate relationship) with respect to the imaging lens 8, whereby an enlarged image of the limiting opening 40 of the aperture 10 is formed on the irradiation surface 42. Is imaged. In addition, the arrangement | positioning position of LED26 and the focus F have a conjugate relationship.

  Therefore, on the irradiation surface 42, the direct light directly incident on the limiting opening 40 of the aperture 10 from the LED 26 and the first and second reflecting surfaces 34 and 36, similarly to the light flux passing through the limiting opening 40 of the aperture 10. The reflected light incident on the limiting opening 40 of the aperture 10 after being reflected by the light is again superimposed on the irradiation surface 42, and an enlarged image of the limiting opening 40 of the aperture 10 having a uniform illuminance distribution is obtained. The image is formed on 42 (see FIG. 4). In this way, a predetermined irradiation range on the irradiation surface 42 is illuminated. The illuminance distribution in the predetermined irradiation range is a substantially uniform illuminance distribution having an irradiation range L corresponding to the size of the enlarged image of the restricted opening 40 of the aperture 10 that has been imaged.

  Further, since no light leaks outside the limiting opening 40 of the aperture 10, no light leaks outside the predetermined irradiation range. As a result, the contour of the limiting opening 40 of the aperture 10 is clearly imaged on the irradiation surface 42, and the boundary between the predetermined irradiation range and its surroundings is clear and clear.

  By moving the second casing part 16 in the optical axis C direction with respect to the first casing part 14, the irradiation distance WD between the imaging lens 8 and the irradiation surface 42 is adjusted, and so-called focus adjustment is performed. Can do. Thus, even when the irradiation distance WD is different, a clear image of the limiting opening 40 of the aperture 10 can be obtained on the irradiation surface 42 by appropriately adjusting the irradiation distance WD as described above.

The LED lighting device 2 of this embodiment can be applied to various uses. When the LED illumination device 2 is applied to, for example, a reading lamp, the light emitted from the LED illumination device 2 illuminates only books, newspapers, etc. at hand of the user, and light leakage to the surroundings is prevented. Thereby, it is possible to prevent a person around the user from being dazzled. Further, when the LED illumination device 2 is applied to, for example, a medical illumination device, the light emitted from the LED illumination device 2 illuminates only the affected area of a patient lying on an examination table, a dental examination table, etc. Light leakage is prevented. Thereby, it can prevent that a patient leaks in a patient's eyes and a patient is dazzled. Further, when the LED illumination device 2 is applied to, for example, an illumination device for image processing inspection, when a work (not shown) arranged on the irradiation surface 42 is imaged by a CCD camera, in the peripheral portion of a predetermined irradiation range. Good imaging data can be obtained without preventing a decrease in illuminance.
[Second Embodiment]
Next, with reference to FIG.5 and FIG.6, the LED lighting apparatus of 2nd Embodiment is demonstrated. FIG. 5A is a perspective view showing a state in which the aperture width of the aperture limiting aperture of the LED lighting device according to the second embodiment of the present invention is increased, and FIG. 5B is the aperture limiting aperture. FIG. 6 is a perspective view showing a state in which the opening width of the aperture is reduced, and FIG. 6 is a diagram for explaining the illuminance distribution in a predetermined irradiation range by the LED illumination device in a state in which the opening width of the aperture opening of the aperture is reduced FIG. In each of the embodiments described below, the same reference numerals are given to substantially the same components as those in the first embodiment, and the description thereof is omitted.

  In the LED lighting device 2A of the present embodiment, an opening variable mechanism 44 for changing the size of the limiting opening 40A of the aperture 10A is provided. The aperture 10A includes a pair of substantially L-shaped aperture members 46a and 46b that are movably combined with each other, and a rectangular limiting opening 40A is formed inside the pair of aperture members 46a and 46b. Yes. In addition, the pair of aperture members 46a and 46b are separated from each other (that is, a direction indicated by an arrow S in FIG. 5A) or directions close to each other (that is, the drawings) by a drive mechanism (not shown). 5 (b) in the direction indicated by the arrow R). When the pair of aperture members 46a and 46b move in a direction approaching each other, as shown in FIG. 5B, the size of the limiting opening 40A of the aperture 10A is reduced, and the opening width is D1 '. Further, when the pair of aperture members 46a and 46b move away from each other, as shown in FIG. 5A, the size of the limiting opening 40A of the aperture 10A increases, and the opening width thereof is D1 (> D1 ′). The opening variable mechanism 44 includes a pair of aperture members 46a and 46b and a drive mechanism.

  As shown in FIG. 6, when the opening width of the limiting opening 40A of the aperture 10A is reduced from D1 (see FIG. 4) to D1 ′, the light flux passing through the limiting opening 40A of the aperture 10A is smaller than the state shown in FIG. In addition, the irradiation range L ′ on the irradiation surface 42 is also reduced. In this way, by changing the size of the limiting opening 40A of the aperture 10A, the size of the enlarged image of the limiting opening 40A of the aperture 10A formed on the irradiation surface 42 is changed, and a predetermined value on the irradiation surface 42 is obtained. The size of the irradiation range can be adjusted.

The drive mechanism for moving the pair of aperture members 46a and 46b can be driven by, for example, an electric motor or manually. In the present embodiment, the aperture 10A is composed of a pair of aperture members 46a and 46b. However, the configuration of the opening variable mechanism 44 can be set as appropriate.
[Third Embodiment]
Next, with reference to FIG. 7, the LED lighting apparatus of 3rd Embodiment is demonstrated. FIG. 7 is a diagram for explaining the illuminance distribution in a predetermined irradiation range by the LED lighting device according to the third embodiment of the present invention.

  In the LED illumination device 2 </ b> B of the present embodiment, a field lens 48 is supported on the support frame portion 38 of the reflection tube 6. The field lens 48 is disposed between the aperture 10 and the imaging lens 8B so as to cover the limiting opening 40 of the aperture 10. The field lens 48 is composed of a convex lens, and the optical axes of the field lens 48 and the imaging lens 8B are coincident with each other.

By providing the field lens 48 in this manner, the light emitted from the vicinity of the outside of the limiting opening 40 of the aperture 10 is bent by the field lens 48 in a direction approaching the optical axis and emitted from the field lens 48. . As a result, the light incident near the outside of the imaging lens 8B can be drawn inward, so that the range of the light beam incident on the imaging lens 8B can be narrowed. As a result, the size of the imaging lens 8B can be reduced, and the entire LED lighting device 2 can be reduced in size.
[Fourth Embodiment]
Next, with reference to FIG. 8, the LED lighting apparatus of 4th Embodiment is demonstrated. FIG. 8 is a diagram for explaining the illuminance distribution in a predetermined irradiation range by the LED lighting device according to the fourth embodiment of the present invention.

  In the LED illumination device 2 </ b> C of the present embodiment, the diffusion plate 50 is supported on the support frame portion 38 of the reflection tube 6. The diffusing plate 50 is disposed between the aperture 10 and the reflecting tube 6 so as to cover the exit side opening 30 of the reflecting tube 6. The direct light emitted from the LED 26 and the light reflected by the reflecting tube 6 are respectively incident on the diffusion plate 50, and the light beams diffused and emitted from the diffusion plate 50 are restricted by the restriction opening 40 of the aperture 10.

  When the diffusing plate 50 is not provided, the image of the LED 26 is formed between the imaging lens 8 and the irradiation surface 42 as described above. Therefore, when the irradiation distance WD is short, the LED 26 is formed on the irradiation surface 42. There is a possibility that an image of the wiring pattern will be reflected. By providing the diffusing plate 50 as in the present embodiment, one side of the diffusing plate 50 (the surface on the aperture 10 side) serves as a secondary surface light source, and thus the LED 26 is disposed between the imaging lens 8 and the irradiation surface 42. An image is prevented from being formed, and even when the irradiation distance WD is short, the influence on the irradiation surface 42 such as an image of the wiring pattern of the LED 26 reflected on the irradiation surface 42 can be reduced.

  As mentioned above, although various embodiment of the LED lighting apparatus according to this invention was described, this invention is not limited to this embodiment, A various deformation | transformation thru | or correction | amendment are possible without deviating from the scope of the present invention.

  In each of the above embodiments, one LED 26 is mounted on the mounting substrate 24, but a plurality of LEDs 26 that are collectively arranged may be mounted.

  Moreover, in each said embodiment, although LED26 and the reflection cylinder 6 were each formed in the rectangular shape, you may form these in circular shape or elliptical shape, for example, and those shapes can be set suitably.

2, 2A, 2B, 2C LED illumination device 6 Reflecting cylinder 8, 8B Imaging lens 10, 10A Aperture 26 LED
28 entrance side opening 30 exit side opening 32 reflecting surface 34 first reflecting surface 36 second reflecting surface 40, 40A limiting opening 42 irradiation surface 44 variable aperture mechanism 48 field lens 50 diffuser plate

Claims (5)

An LED, a reflecting tube for reflecting light emitted from the LED, an imaging lens provided in front of the reflecting tube, and a limiting opening provided between the reflecting tube and the imaging lens; And an aperture having
A reflective surface is formed on the inner surface of the reflective cylinder, and the reflective surface extends from the incident side opening of the reflective cylinder toward the exit side opening, and the incident side opening of the reflective cylinder The part is arranged so as to cover the periphery of the LED,
The luminous flux of the direct light from the LED and the reflected light from the reflecting cylinder is limited by the limiting aperture of the aperture, and the limited luminous flux is imaged on the irradiation surface by the imaging lens. LED lighting device.   The LED illumination device according to claim 1, wherein a field lens is provided between the aperture and the imaging lens.   The LED lighting device according to claim 1, wherein a diffusion plate is provided between the LED and the aperture. The LED is configured in a rectangular shape. Correspondingly, the reflecting tube has a rectangular cross section, and the reflecting surfaces of the reflecting tube are a pair of first reflecting surfaces facing each other in a predetermined direction. And a pair of second reflecting surfaces facing each other in a direction orthogonal to the predetermined direction,
The pair of first reflective surfaces are respectively disposed corresponding to the two opposite sides of the LED, and the pair of second reflective surfaces are disposed corresponding to the remaining two sides of the LED. The LED lighting device according to claim 1, wherein the LED lighting device is provided.   The LED illumination device according to any one of claims 1 to 4, further comprising an opening variable mechanism for changing a size of the limiting opening of the aperture in relation to the aperture.

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