JPS60230618A - Original lighting device - Google Patents

Abstract

PURPOSE:To widen an area where high illuminance is obtained by providing a reflection converging means which converges reflected light from an object of lighting again between a light source and the object of lighting near the object of lighting. CONSTITUTION:A condenser lens 3 converges light from an LED chip 2 to light up an original 10 through a window 6 for lighting so as to obtain the peak of the illuminance distribution of the original. Light which is reflected irregularly by the original 5 is converged again by the reflection converging means 5 to light up the original 10. A support 4 supports the reflection converging means 5, which is installed fixedly near the original 10. In this case, a reading is performed by using transmitted light from the reverse surface of the original 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document illumination device. More specifically, the present invention relates to a document illumination device comprising a high-intensity LED array light source that can be used to illuminate the document surface of an image reading device such as a facsimile machine or an electrophotographic copying machine.

[Prior art]

In recent years, there has been an increasing demand for miniaturization of facsimile machines, electrophotographic copying machines, and similar image reading devices.
An IJD array in which a large number of JD Chizzos are arranged is used. The LED array has the advantage of being small and durable, but on the other hand, the absolute amount of light is small, making it difficult to obtain a sufficient amount of light for reading a document.

In the conventional LED array configuration, among the light beams emitted from LEDs 1 and 5, only the light beams that pass near the center of the condenser lens are condensed at the center, forming a peak in the illuminance distribution. However, the light flux that has passed through the peripheral area is diffused to form the base of the illuminance distribution, resulting in illumination that is widely diffused on the light receiving surface of the illumination target, so its contribution to the illuminance at the center of the light receiving surface is small. The illuminance to illuminate the original may not be sufficient.

That is, when using a conventional LED array to illuminate a document in an image reading device, the surface of the document is used as the light-receiving surface, and the part of the document to be read is aligned with the center of the light-receiving surface where the highest illuminance can be obtained. However, the only luminous flux contributing to the illuminance at the center of the light-receiving surface was the light flux directly entering the vicinity of the center of the condenser lens from the LED Chizzo. is limited to a narrow area at the center of the light-receiving surface, and it is difficult to align this area with the part of the document to be read.

(2) Even at the peak of the light-receiving surface illuminance distribution (at the center of the light-receiving surface), the illuminance obtained is small and insufficient.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks, effectively utilize the light source of the LED array with a simple structure, and provide a wide area on the light-receiving surface of an original where high illuminance can be obtained, so that the peak of the light-receiving surface illuminance distribution is An object of the present invention is to provide a document illumination device that can provide high-intensity illumination.

[Summary of the invention]

An object of the present invention is to provide an illumination device that uses an LED array as a light source and is provided with a condensing lens or a condensing reflector and a condensing lens. This is achieved by a document illumination device characterized in that a reflection and convergence means for condensing the reflected light from the object is installed near the object to be illuminated.

〔Example〕

An embodiment of the document illumination device of the present invention will be described in detail with reference to the drawings.

FIG. 1 (color) shows a plan view of the document illumination device of this embodiment, FIG. 1(b) shows a front view, and FIG. 1(c) shows a side view. As shown in the figure, LED chips f2 are arranged at equal intervals in the longitudinal direction of the substrate 1, and serve as a light source. Support bodies 4 are provided vertically on both sides of the substrate 1, facing each other, and a cylindrical condenser lens 3 is installed. Reference numeral 5 denotes a reflection and convergence means installed above the support 4, and an illumination window 6 is provided in the center. 9
1 is a light receiving element array, and 10 is an original. Condensing lens 3
The light from the LED chip f2 is focused and converged to illuminate the document 10 through the illumination window 6 so that the peak of the illuminance distribution is reached. The light irradiated onto the original 10 and diffusely reflected is condensed and converged again by the reflection/convergence means 5 to illuminate the original 1°.

The support body 4 supports the reflection and convergence means 5, and the reflection and convergence means 5 is installed and fixed in the vicinity of the document 0. In this case, reading is performed using transmitted light from the back side of the original 1o. The light-receiving element array 9 for reading can also be brought into close contact with the back surface of the original 10.

Further, it is possible to use a lens in the vicinity of the original 10 to condense and image the image, and is not limited to the embodiment of this embodiment. In the example shown in FIG. 2, a light condensing reflector plate 3' is provided on the side surface of the LED chip 2. FIG. 3 shows a sectional view of a second embodiment of the document illumination device of the present invention.

In the second embodiment, since reading is performed using reflected light, a reading window 7 is provided on the reflection and convergence means 5 disposed near the original 10 on the optical axis where the light is condensed. There is. Here, the reading means in the second embodiment is composed of a converging light transmitting body 8 and a light receiving element/array 9 (CCD line sensor). The light receiving element array 9 (CCD line sensor) is arranged on a conjugate plane on the optical axis of the same magnification image formation. The reflection and convergence means 5 is disposed between the convergent light transmitter 8 and the original 10 and has a reading window 7 with respect to the convergent light transmitter 8 . Figure 4 shows the IJD Chizzo 2 in Figure 3.
Concentrating reciprocal light on the side of Hm? , ' is a cross-sectional view of a document illumination device provided with. The reflecting plate 3' further improves the illumination intensity of the original 10. The shape of the reflection and convergence means 5 is preferably a semi-cylindrical shape with a 1/4 spherical end surface, since the irradiated light diffusely reflected from the original 10 returns to the original 10 again. Reflection convergence means 5
It is preferable that the number of illumination windows 6 and reading windows 7 that can be opened at the same time is as small as possible.

The reflection and convergence means 5 is constructed by nickel plating a plastic molded product. Similarly, the condensing reflector 3' may be formed by plating a plastic molded product with nickel, or may be formed by vapor deposition of aluminum.

By providing the reflection and convergence means 5, normally about 50% of the diffusely reflected light is focused again on the surface of the original 1.
Since it can be used for zero illumination, the illuminance on the document surface is dramatically improved.

〔Effect of the invention〕

According to the present invention, the light source of the LED play is effectively used, the diffusely reflected light from the document is again focused and converged, the width of the illuminance distribution on the document is widened, and the illuminance illumination shows a higher peak. A high-performance, highly efficient document illumination device that facilitates reading by a reading device can be obtained.

[Brief explanation of drawings]

FIG. 1(-) is a plan view of the document illuminating device of the present invention. FIG. 1(b) is a sectional view taken along line A-A' in FIG. 1(-). FIG. 1(C) is a sectional view taken along line B-B' in FIG. 1(,). FIG. 2 shows another embodiment of the document illumination device according to the present invention.
It is a B' sectional view. FIG. 3 is a sectional view of another embodiment of the document illumination device of the present invention. FIG. 4 is a sectional view showing another embodiment of FIG. 3. DESCRIPTION OF SYMBOLS 1... Substrate, 2... IJD chip, 3... Condensing lens, 4... Support body, 5... Reflection convergence means, 6...
- Illumination window, 7... Reading window, 8... Focusing light transmitter, 9 - Light receiving element array, 10... Document, 3'...
・Reflector for light collection. Figure 2

Claims (1)

[Claims] In an original illuminating device, the light source is I and ED chips arranged in tandem on a substrate, and a condensing lens is provided on the substrate. A document illumination device characterized in that a reflection and convergence means for condensing light is installed near the object to be illuminated.