JPS6159440A - Lighting device of copying machine or the like - Google Patents

Abstract

PURPOSE:To separate a large lighting area by colors through a single optical element by providing a color separation sheet between a means which converts luminous flux emitted by a spot light source into parallel luminous flux and a means which converges the light linearly. CONSTITUTION:The light emitted by the spot light source 1 made of a small- sized halogen lamp is transmitted through a slit 2 and then collimated by a parallel luminous flux projector 3 into the parallel luminous flux. This parallel luminous flux collimated by this parallel luminous flux projector 3 is color- separated by the color separation sheet 4 and then converged by the converging optical element 5 linearly on an original 6 to be copied or read, thereby illuminating the original.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an illumination device mainly used in copying machines and the like, which allows color separation of a large area of illumination by a single optical element.

2. Description of the Related Art Conventionally, when color separation is performed in color copying machines, factor cameras, etc., optical elements such as color separation filters and dichroic lenses are used.

Since these optical elements have constant spectral, transmittance, and spectral reflectance, 1 For example, as shown in FIG.
When color-separating the parallel light beam C projected by
The problem is that it requires an operation to move the light in and out of the optical path, making the structure complicated.

Further, as a color separation method using a single optical element, there is a method using a prism or a diffraction grating. For example, as a method for selectively condensing light using a reflection type diffraction grating,
The one described in No. 6-24872 is known.

Problems to be Solved by the Invention However, the device described in the above publication uses expensive prisms and diffraction gratings, which makes the device itself expensive and makes it difficult to accurately manufacture optical elements that illuminate a large area. There was a problem with Hikodo.

This invention was made for the purpose of improving the above-mentioned problems.

Means for solving the problem and point of action A color separation sheet is provided between the means for converting the luminous flux emitted from the point light source into a parallel luminous flux and the means for condensing the light into a line to convert the luminous flux from one point light source. A lighting device that focuses light into a line for each color and is mainly used for color copying machines, facsimile machines, etc.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, 1 is a point light source such as a small-sized 10-gen lamp, and the light emitted from this point light source 1 is projected as a parallel beam after passing through a slit 2. It is collimated into a parallel beam by the device 3. The parallel beam projector 3 has a focal length of, for example, 105 wn, F
2. The parallel light beam collimated by this parallel light beam projector 3 is transferred to the color separation sheet 4.
After color separation, the condensing optical element 5 condenses the light into a line onto an original 6 to be copied or read, and illuminates it. The illumination distribution in the document illumination section at this time is as shown in FIG. The color separation sheet 4 has an apex angle α of 40° as shown in FIG. The converging optical element 5 was tilted by the polarization angle of the one color separation sheet 4 used.

On the other hand, the reflected light from the original 6 is guided onto a photoreceptor or a solid-state imaging device (CCD) by a powerful optical system as shown in the figure, and an electrostatic latent image is formed on the photoreceptor or is read. . By moving the position of the slit 2, an electrostatic latent image for each color can be formed at a predetermined position on the photoreceptor. Further, in the case of a solid-state image sensor, by changing the position of the embryonic element, it becomes possible to read image information of the necessary color.

In the case of the above embodiment, the luminous flux separated into five colors is condensed to a half-width of 3, and the distance between each color (R, G, B) is approximately I between the blue and the edges.
The distance between Wfla Green and Hikari was about 1.5 barrels. The polarization angle of the bright blue-green light 515 rtm+1 was 34°.

On the other hand, if the distance between the color separation sheet 4 and the condensing optical element 5 is increased, the red light and blue light, centering on the green light, will increase by +1°, -0°, respectively.
The beam spreads by 6 degrees and deviates from the width of the condensing optical element 5, causing a decrease in the amount of red light and blue light.

Therefore, as shown in FIG. 4, the color separation sheet 4 and the condensing optical element 5 may be laminated to perform color separation and light condensation at the same time as shown in FIG. 5.

FIG. 6 shows another embodiment in which a parabolic reflector 7 is used to collimate the light from the point light source 1 into a parallel beam, and a parabolic reflector 8 is used to condense the parallel beam into a line. It is something. Furthermore, in order to eliminate unevenness in illuminance, a light shielding plate 9 is provided in front of the parabolic reflex taph to correct the illuminance distribution. In the above device, since color separation is not performed on the imaging optical path, an inexpensive one can be used as a single color separation element.Advantageous Effects of the Invention As described in detail above, this invention uses a single optical element. Not only can a large illumination area be color-separated, but the use of inexpensive color separation sheets can also reduce the cost of the entire device.

[Brief explanation of the drawing]

FIG. 1 is a side view showing one embodiment of the present invention. Fig. 2 is an enlarged side view of the color separation sheet, Fig. 3 is a diagram showing the illuminance distribution, Figs. 4 to 6 are explanatory drawings showing other embodiments, and Fig. 7 is an explanatory drawing of the conventional method. . 1 is a point light source, 4 is a color separation sheet, and 6 is a manuscript.

Claims (1)

[Claims] In the device that illuminates the original 6 by converting the light beam emitted from the point light source 1 into a parallel light beam and condensing the light in a line onto the original 6 by a condensing means, there is a space between the parallel light flux converting means and the condensing means. An illumination device for a copying machine, etc., in which a color separation sheet 4 is interposed between the two.