JP4314837B2 - Light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a strobe device that is used as an auxiliary light source for taking a picture, and more specifically, is small and bright and can illuminate only a necessary range, such as a built-in mobile phone.
[0002]
[Prior art]
In recent years, various types of mobile phones with cameras have been provided. For example, as shown in FIG. 5, a camera-equipped mobile phone disclosed in Patent Document 1 has various buttons 2 for inputting numbers and characters on the lower part of the front surface of the exterior body 1, and a release button used for photographing. 3 is arranged, a liquid crystal display 4 for displaying communication information and images is arranged on the upper part, and an electronic camera 5 with a lens exposed on the upper side of the display 4 and a strobe device 6 are arranged side by side. ing.
[0003]
The strobe device 6 includes a protector for closing a window portion formed in front of the exterior body 1, a reflector umbrella embedded in the exterior body 1 from the window portion, and a strobe discharge tube disposed in the reflector body. Has been. The electronic camera 5 has a function of forming an image of a subject on a light receiving surface, performing photoelectric conversion, and outputting the image data. Image data is recorded on a recording medium such as a memory card via an interface.
[0004]
Then, the image captured by the electronic camera 5 is displayed on the display 4 by operating the release button 3. When the release button 3 is operated in a dark place, the strobe device 6 automatically operates, the strobe discharge tube illuminates the subject, and the electronic camera 5 images the subject. The captured image data of the subject is recorded on a recording medium or transmitted as an e-mail.
[0005]
Meanwhile, there is a demand for further reducing the size of the strobe device 6 built in the mobile phone and reducing the power consumption. Therefore, it can be said that it is more appropriate to use an LED lamp than a strobe discharge tube as a light emitting device of the strobe device 6 incorporated in the mobile phone.
[0006]
The LED lamp is obtained by molding an LED chip mounted on a lead frame into a convex lens shape with a transparent resin, and a compact and low power consumption type that emits white light is also provided. Further, the outer diameter of the convex lens-shaped resin is set to 5 mm or less because of the difference in thermal expansion coefficient between the LED chip and the resin.
[0007]
An LED lamp that can be used as a vehicle lamp such as a tail lamp has been proposed (see, for example, Patent Document 2). The LED lamp includes a first optical unit that gives an appropriate irradiation angle to light from the LED chip, and a lens-shaped second optical unit that is provided via an air layer at a position that receives light from the first optical unit. Means. Said 1st optical means is comprised from the concave mirror which arrange | positions an LED chip, and the dome-shaped lens part which fills the LED chip in a concave mirror with resin. In addition, the second optical means has an outer diameter of about 15 mm so that the light emitting area can be enlarged, and at least one of the surfaces is a lens cut surface. Thus, it is possible to construct a vehicular lamp without uneven brightness.
[0008]
[Patent Document 1]
JP 2001-320622 A [Patent Document 2]
JP 2000-58925 A [0009]
[Problems to be solved by the invention]
By the way, since the LED lamp is a point light source, light is emitted in a conical shape. Therefore, when an LED lamp is employed as the light emitting device of the strobe device 6 of the camera-equipped mobile phone, the LED lamp illuminates the subject in a circle.
[0010]
However, the range taken as a photograph is a rectangle, and even if the LED lamp illuminates the subject in a circle, the light of the portion that projects in a bow shape from the outer periphery of the rectangle does not contribute to the shooting, Not being used effectively.
[0011]
In addition, since the LED lamp disclosed in Japanese Patent Laid-Open No. 2000-58925 does not illuminate the subject in a square shape, it cannot solve the problem of effectively using light, and the first is to increase the light emitting area. The optical means and the second optical means are provided, and cannot be adopted as the strobe device 6 of the mobile phone that is increasingly miniaturized.
[0012]
Accordingly, the present invention is, for example, is employed as a flash device for a camera-equipped mobile phone, to illuminate a square corresponding to the shooting range of the Utsushitai, the object is to be able to effectively use the light To do.
[0013]
[Means for Solving the Problems]
A strobe device according to the present invention is a strobe device in which a convex lens is arranged at a position close to a point light source and illuminates a rectangular imaging range of the imaging device, and the convex lens has an inner surface on the point light source side having a point light source. On the other hand, the outer surface on the opposite side has a radius of curvature of a cross-sectional outline passing through the optical axis orthogonal to the optical axis. Each of the axes is a convex surface that gradually decreases toward the axis side, and of the two axes orthogonal to the optical axis, the curvature radius that gradually decreases toward an axis orthogonal to the longitudinal direction of the imaging range is the imaging range. The curvature radius is smaller than the radius of curvature that gradually decreases toward an axis parallel to the longitudinal direction of the .
[0014]
When a point light source arranged close to such a convex lens emits light, the light is refracted on the inner surface of the convex lens and incident on the convex lens, and refracted in a direction parallel to the optical axis by the outer surface (convex surface) of the convex lens. Go out from the outside. In addition, although the light enters the convex lens in a circular shape, the surrounding convex light that radiates out from the outer surface of the convex lens is refracted toward the center of the convex lens by the curved convex surface formed on the outer surface of the convex lens. Then, it comes out in a shape closer to a square shape, and illuminates the subject in a substantially square shape.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a strobe device according to the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the light emitting device of this embodiment has a convex lens 8 disposed in the vicinity of a point light source 7 such as an LED chip, and the convex lens 8 has a flat inner surface 9 on the point light source 7 side. The outer surface 10 on the opposite side is a curved surface provided with a convex portion 11 and a concave portion 12.
[0017]
That is, on the outer surface 10 of the convex lens 8, a curved convex surface portion 11 having two diagonal lines 13 as arc-shaped ridge lines is formed, and two orthogonal axes orthogonal to the optical axis 14, that is, a center connecting the centers of the sides. A recessed portion 12 that is recessed in the portion of the line 15 is formed. Therefore, the center that is the intersection of the diagonal lines 13 protrudes most, and a notch 16 is formed at the center of each side.
[0018]
Further, on the outer surface 10 of the convex lens 8, the radius of curvature of the outline 17 of the cross section passing through the intersection of the two diagonal lines 13, that is, the center, is gradually decreased from each diagonal line 13 toward each center line 15. Yes.
[0019]
Therefore, the side surface of the convex lens 8 and the cross section parallel to the side surface are as shown in FIGS. As shown in FIG. 2 (B), the side surface of the convex lens 8, that is, the end surface of the line B-B in FIG. 2 (A), is provided with a notch 16 at the center. An end face having a shape that is cut into one is formed. Further, as shown in FIG. 2 (H), a cross section of the convex lens 8 at the center line 15, that is, a cross section taken along the line HH in FIG. 2 (A) is provided with notches 16 on both sides. A semicircular convex surface portion 11 is formed. As shown in FIGS. 2 (C) to 2 (G), each cross section taken along line CC and GG in FIG. 2 (A) between the side surface of the convex lens 8 and the center line 15 has a notch 16. The convex part 11 which becomes shallow gradually and the outline 17 has an arc shape on both sides of the notch part 16 is formed. The radius of curvature of the convex portion 11 gradually decreases from the end surface toward the center line 15 and becomes a complete semicircular shape as shown in FIG. 2 (H) in the cross section at the center line 15 as described above.
[0020]
The curved convex surface portion 11 and the recessed portion 12 can illuminate the light that is about to spread in a circular shape. And, for example, suitable for photography, the intersection radius of the two diagonal lines 13, that is, the radius of curvature of the outline 17 of the cross section passing through the center is directed to one center line 15 and the other center line 15 It is possible to make the light come out in a rectangular shape by changing the refractive index of light and the refractive index of light.
[0021]
Such a convex lens 8 is fitted into a socket 19 fixed on a substrate 18 as shown in FIG. On the substrate 18 in the socket 19, a point light source 7 such as a compact and low power consumption LED chip is mounted so as to face the center of the convex lens 8. In other words, the point light source 7 is disposed on the optical axis 14 obtained by extending a line extending from the most protruding center of the outer surface 10 of the convex lens 8 to the inner surface 9. Further, the inner surface 9 of the convex lens 8 is disposed close to the point light source 7 so that all the light emitted from the point light source 7 enters the convex lens 8.
[0022]
The strobe device mounted on such a substrate 18 is arranged so that each side of the square of the convex lens 8 is parallel to each side of the exterior body 1 in the exterior body 1 (see FIG. 5) of the camera-equipped mobile phone. Provided. The mobile phone is provided with an electronic camera 5, a release button 3, and the like (see FIG. 5).
[0023]
When the point light source 7 emits light, the light on the optical axis 14 is input perpendicularly to the inner surface 9 of the convex lens 8 and goes straight out from the outer surface 10. The light spreading in a circular shape from the optical axis 14 enters the bottom surface of the convex lens 8 in an oblique direction and is refracted toward the optical axis 14. Then, a curved convex surface portion 11 and a concave portion 12 are formed on the outer surface 10 of the convex lens 8, and the concave portion 12 extends in a circular shape and protrudes from the outer surface 10 by being recessed at the center line 15 of each side. The light to be refracted into a quadrangular shape and emerges from the outer surface 10 in a substantially quadrangular pyramid shape.
[0024]
That is, as shown in FIG. 4, when it is assumed that the light spreads in a circular shape, the light of the arcuate portion 22 surrounded by each side 20 and the circular arc 21 inscribed in the circular shape is the convex surface of the convex lens 8. The light is refracted toward the optical axis 14 by the portion 11 and the recessed portion 12. The light of the arch-shaped portion 22 is small on both sides and increases in the middle portion, but the light in the middle portion is strong due to the concave portion 12 formed in a curved shape at the center line 13 portion of the convex lens 8, and the light on both sides. Is weak and refracts toward the optical axis 14. Therefore, the light emitted from the outer surface 10 of the convex lens 8 is irradiated in a substantially quadrangular pyramid shape as shown in FIG.
[0025]
Therefore, when the electronic camera 5 provided in the mobile phone is directed toward the subject and the release button 3 is operated in a dark place, the point light source 7 emits light and illuminates the subject from the convex lens 8 in a square shape. Since each side of the convex lens 8 is parallel to each side of the exterior body 1 of the mobile phone, a range captured by the electronic camera 5 can be illuminated by a strobe device, and light can be used effectively.
[0026]
The present invention is not limited to the embodiment of the invention, and can be variously modified within the scope of technical matters described in the claims. For example, engagement Luz in flash device of the present invention is not intended to be built in the cellular phone, not only can be carried out similarly even external, it may also be provided in various cameras other than the mobile phone. The point light source is not limited to the LED chip. Further, the inner surface of the convex lens may be a concave surface or a convex surface centered on the optical axis, instead of a flat surface.
[0027]
【The invention's effect】
According to the present invention, the outer surface of the convex lens arranged close to the point light source includes a special convex surface portion, so that the arcuate portion around the light emitted in a circular shape is refracted toward the optical axis, It can be illuminated in a square shape. Therefore, it is possible to accurately irradiate only the range to be imaged, to suppress irradiation spots, to effectively use light, and to extend the battery life by reducing power consumption. Will be able to.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an embodiment of a lighting device according to the present invention. FIG. 2 shows an embodiment of a lighting device according to the present invention.
(A) is a plan view (B) is a side view (C) to (H) is a cross-sectional view taken along line CC to HH in FIG. (A). FIG. 4 is a schematic perspective view showing a state illuminated by the illumination device according to the present invention. FIG. 5 is a front view of a camera-equipped mobile phone.
7 Point light source 8 Convex lens 9 Inner surface 10 Outer surface 14 Optical axis 15 Center line (two orthogonal axes orthogonal to the optical axis)
17 Outline

Claims (1)

Convex lens is disposed at a position close to a point light source, a strobe device you illuminate a rectangular imaging range of the imaging device, the convex lens, the inner surface of the point light source side, a flat perpendicular to the optical axis of the point light source while that is concave or convex surface to the surface or around the optical axis, the outer surface of the opposite side, the radius of curvature of the outline of the cross-section passing through the optical axis, toward the respective axis side of the orthogonal two axes perpendicular to the optical axis Of the two axes orthogonal to the optical axis, and the radius of curvature gradually decreasing toward the axis orthogonal to the longitudinal direction of the imaging range is parallel to the longitudinal direction of the imaging range. A strobe device having a radius of curvature smaller than the radius of curvature that gradually decreases toward the surface.

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