JP2652092B2 - Lighting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device used in a copying machine or the like, and more particularly to an illuminating device which scans an illuminated area by fixing a light source and moving a reflecting optical system.

[0002]

2. Description of the Related Art Conventionally, as an illumination device for scanning an illuminated area by moving only a reflection optical system with respect to a fixed light source, the one shown in Japanese Patent Publication No. 53-41976 is known. I have. For example, as shown in FIGS. 9 to 11, the light from the light source 100 is converted into a parallel light beam using a parabolic mirror 120 having the light source as a focal point or another collimating lens, and the parallel light beam is received. The light is condensed using a parabolic reflector 110 having a substantially focal point in the illumination area W, and the reflector 110 forming a part of this reflection optical system is used.
Are scanned to scan the illuminated area.

[0003]

However, in the prior art, as described above, the luminous flux from the light source 100 is reduced by one.
Only one parabolic mirror 120 and one other collimating lens attempt to collimate (parallelize) the divergent light beam at a stretch.

However, the parabolic mirror and the collimating lens for collimating are formed to be elongated as shown in FIG. Therefore, the collimated light beam has a length in the longitudinal direction of 200 to 300 mm,
The width direction is only about 30 to 40 mm which is several times the slit width. Therefore, the distance between the light source and the vertex of the curved surface is substantially determined by the longitudinal width of 200 to 300 mm, and the two cannot be brought close to each other. Therefore, there has been a problem that the light-condensing efficiency of the light in the short direction becomes extremely poor.

In the longitudinal direction, a considerably large angle can be condensed. On the contrary, the difference in light amount between the central portion and the peripheral portion in the longitudinal direction becomes too large. Therefore, in order to adjust the amount of light to the peripheral portion, the amount of light in the central portion usually has to be reduced by a large amount by using a filter or a photoelectric correction plate. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to first collimate a light beam from a fixed light source in one direction only by a first deflecting means. For the vertical direction,
Orthogonal to each other, such as collimating by the deflection means of
It is possible to collimate near the light source by using two independent deflecting means with collimating function in one direction without changing the convergence at all in one direction. Another object of the present invention is to provide a lighting device that can increase the light collection efficiency and reduce the size.

[0007]

In order to achieve the above object, according to the present invention, there is provided a fixed point light source and a semi-cylindrical shape having the point light source as a focal point and having a collimating function in one direction. A reflecting mirror, a cylindrical lens having a collimating function in another vertical direction that is not collimated with respect to a light beam emitted from the reflecting mirror, and a movement in which the light beam emitted from the cylindrical lens is focused on an illuminated area. It is characterized by having scanning type light collecting means.

[0008] The reflecting mirror may be formed so that the cross section of the half-cylinder shape is shaped to draw a parabola, or the cross section of the half-cylinder shape may set the point light source position to one focus. Can be formed so as to form a part of an ellipse.

If the cylindrical lens is formed as a cylindrical Fresnel lens, the thickness can be reduced.

[0010]

The luminous flux emitted from the light source is first collimated in one direction by a reflecting mirror serving as a first deflecting means.
Enter the cylindrical lens. Next, when this cylindrical lens serves as the second deflecting means and performs collimation in the vertical direction, a complete parallel light beam reaches the condensing means and is condensed on the illuminated area.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a lighting device according to a first embodiment of the present invention, where 1 is a fixed point light source. In order to collimate the divergent light beam from the point light source 1 in the vertical direction, a reflecting mirror 2 is disposed with the point light source as a focal point.
The reflecting mirror 2 is a first deflecting means, and reflects light from the point light source 1 on an inner surface of a semi-cylindrical shape, and its cross section (a cross section cut in the vertical direction in FIG. (See 3)
Is shaped to draw a parabola.

Next, as shown in FIG. 2, the reflected light beam from the reflecting mirror 2 is received, and is received in another vertical direction (horizontal direction in FIG. 1).
It is arranged to collimate about 3
Is a cylindrical lens. The cylindrical lens 3 serves as a second deflecting unit, and the light beam that has passed through the cylindrical lens 3 becomes a complete parallel light beam. Then, by the reflecting mirror 4 as a condensing means of the moving scanning system,
As shown in FIG. 3, light is focused on the illuminated area.

According to the apparatus of this embodiment having the above structure, the divergent light emitted from the point light source 1 is collimated by the semi-cylindrical reflecting mirror 2 only in the short direction (vertical direction in FIG. 1) and in the long direction (FIG. 1). 2, there is no light-gathering power, and as shown in FIG. 2 shown from above in FIG. It becomes a diverging luminous flux as if there is a light source. The cylindrical lens 3 collimates the light diverging in the longitudinal direction. After passing through the cylindrical lens 3, the light beam is collimated in all of the vertical and horizontal directions, and becomes a complete parallel light beam.

If the focal length of the cylindrical lens 3 is set to be longer than the focal length of the reflecting mirror 2 in the lateral direction, the light quantity ratio between the central part and the peripheral part in the longitudinal direction is smaller than in the conventional case. You can also.

As is apparent from FIG. 3, which shows FIG. 1 from the side, the reflecting mirror 2 does not have a curvature in the longitudinal direction unlike the conventional device, so that the reflecting mirror 2 is not enlarged and the conventional mirror is not used. Since the shape is relatively easy to make, the distance between the light source 1 and the reflecting mirror 2 can be reduced, and the light collection efficiency can be increased in the short direction.

As described above, the luminous flux completely collimated by the reflecting mirror 2 and the cylindrical lens 3 converts the illuminated area 6 into a slit shape by the reflecting mirror as a converging means of a moving scanning system shown in FIG. Illuminate while scanning.

Reference numeral 5 in FIGS. 1 to 3 denotes a small reflecting mirror for returning a light beam directly traveling in the direction of the cylindrical lens 3 to the direction of the point light source 1 again. The reflecting mirror 5 further enhances the illumination efficiency, and also has a function of removing stray light traveling toward the cylindrical lens 3.

FIG. 4 shows an improved example of the moving reflecting mirror 4 shown in FIG. That is, an example in which the reflecting mirror 4 is divided into two parts is shown. By illuminating the illuminated area from the left and right in this way, for example, when copying a document such as a cut-and-pasted document by illuminating, a shadow of a step is seen. A lighting system that is difficult to stand up can be obtained.

FIG. 5 shows a lighting device according to a second embodiment of the present invention. The cylindrical lens 3 employed in the first embodiment described above is, for example, an integral glass,
It is made of a transparent synthetic resin or the like, and becomes heavy when the illumination width is as large as about 300 mm. Also, FIG.
In the example shown in FIG. 3, the refracting surface of the cylindrical lens for collimating is generally an aspherical surface (in the case of the first embodiment, it has a hyperbolic shape), which tends to be difficult to manufacture and costly. There is. FIG. 5 shows a second example in which the cylindrical lens 3 is replaced with a cylindrical Fresnel lens 31 in order to avoid such a situation. By doing so, it is possible to realize a lightweight and inexpensive system.

The apparatus of the present embodiment can be configured in the same manner as the apparatus of the above-described first embodiment except for the components that employ the cylindrical Fresnel lens 31.

FIG. 6 shows a lighting device according to a third embodiment of the present invention. The same components as those in the first embodiment described above will not be described repeatedly, and only the features will be described.

This embodiment shows an example in which the parabolic cylinder surface 2 used in the first embodiment shown in FIGS. 1 to 3 is replaced with an off-axis parabolic cylinder surface 21. By adopting such a configuration, it is possible to prevent the light flux collimated in the short direction from being affected by vignetting of the reflecting mirror 5 for preventing stray light.

FIG. 7 shows a lighting device according to a fourth embodiment of the present invention. This embodiment is also described focusing on the characteristic portions. In the first to third embodiments, assuming that the light source is a perfect point light source, the parabolic cylindrical mirror 2 is used as a half-cylindrical reflecting mirror for collimating the light beam in the lateral direction. However, since the actual light source has a finite size to some extent, the light beam incident on the parabolic mirror 2 and reflected is a slightly divergent light beam. In order to suppress this effect to a small extent, an embodiment using an elliptical cylindrical surface slightly deviated from the parabolic cylindrical surface instead of the parabolic cylindrical surface will be described as the present embodiment.

In FIG. 7, instead of the parabolic mirror shown in FIG. 3 for the first embodiment, the light source position slightly deviated from the parabolic cylinder surface is used as the first focal point, and the second focal point 10 is used as the scanning reflector 4. Is formed as an elliptical cylindrical mirror 22 having a cylindrical shape extending in a direction perpendicular to the light source and a plane including the ellipse. According to this embodiment, the above-mentioned disadvantages are eliminated, and the light use efficiency can be further improved.

FIG. 8 shows a fifth embodiment of the present invention in relation to the fourth embodiment. This is an example in which the off-axis parabolic cylindrical surface 21 of the third embodiment shown in FIG. 6 is replaced with a similar off-axis elliptical cylindrical mirror 23. According to this embodiment, the light use efficiency can be further improved. 7 and 8 showing the fourth and fifth embodiments, the second deflecting means is represented by a cylindrical lens 3 having a focal line as a quasi line of the approximate ellipse parabola (parabola before shifting). However, this may employ a cylindrical Fresnel lens as shown in FIG. 5, and by using a Fresnel lens, weight reduction and cost reduction can be achieved as described in the second embodiment.

[0026]

According to the present invention, there is provided a reflecting mirror as a first deflecting means for collimating divergent light emitted from a point light source in one direction and a second collimating means in a vertical direction. By independently disposing the cylindrical lenses as the deflecting means, the reflecting surface 1 of the conventional paraboloid of revolution (or a surface close thereto) can be obtained.
Compared to a system in which the collimator is collimated at once, the shape can be easily formed and is small, and the short and long directions can be independently optimized, so that it is possible to provide an efficient lighting device.

Further, by configuring the cylindrical lens as a cylindrical Fresnel lens from a single glass lens, the effects of weight reduction and cost reduction can be expected.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a lighting device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing the first embodiment.

FIG. 3 is a side view showing the first embodiment.

FIG. 4 is a diagram showing a modification of a part of the first embodiment.

FIG. 5 is a plan view showing a lighting device according to a second embodiment of the present invention.

FIG. 6 is a side view showing a third embodiment of the present invention.

FIG. 7 is a side view showing a fourth embodiment of the present invention.

FIG. 8 is a side view showing a fifth embodiment of the present invention.

FIG. 9 is a perspective view showing a conventional lighting device.

FIG. 10 is a plan view showing a conventional lighting device.

FIG. 11 is a side view showing a conventional lighting device.

[Explanation of symbols]

 1 point light source 2 semi-cylindrical reflector 3 cylindrical lens 4 reflector (moving scanning system)

Claims (4)

(57) [Claims] 1. A fixed point light source, a semi-cylindrical reflecting mirror having the point light source as a focal point and having a collimating function in one direction, and a light beam emitted from the reflecting mirror is collimated. An illumination device comprising: a cylindrical lens having a collimating function in another vertical direction; and a moving-scanning type condensing means for condensing a light beam emitted from the cylindrical lens in an illuminated area. 2. The illumination device according to claim 1, wherein the reflector has a semi-cylindrical cross-section shaped to draw a parabola. 3. The reflector according to claim 1, wherein the reflector has a semi-cylindrical cross-section having a shape that forms a part of an ellipse having a point light source position as one focal point. The lighting device according to claim 1. 4. The lighting device according to claim 1, wherein the cylindrical lens is formed as a cylindrical Fresnel lens.