JPH03136456A - Original lighting device - Google Patents

Abstract

PURPOSE:To easily obtain desired luminous quantity of lighting and to improve the productivity by providing an opening for ventilation to both ends of a light condensing means in the lengthwise direction. CONSTITUTION:A light condensing means 3 consists of a condenser lens 3-1 condensing luminous flux radiating from a light emission means 2 and a frame 3-2 supporting the condenser lens 3-1 from both sides of a base 1 in the lengthwise direction so as to surround the means 2 and each component is constituted integrally. Then an opening 3-3 for ventilation is provided at both ends of the means 3 in the lengthwise direction. Air flows from the opening 3-3 provided at both ends of the light condensing means 3 at lighting of an original and heat produced from an LED chip 2a and a limit resistor is effectively dissipated. Thus, the desired luminous quantity is introduced as required and various processing methods such as extruder forming and injection forming are adopted for the manufacture process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a document illumination device, and particularly to a document illumination device that surrounds the light emitting means to absorb heat generated during illumination from a light emitting means in which a plurality of light emitting surfaces such as LEDs are arranged in a line. It is suitable for e.g. facsimile, etc., in which heat is efficiently radiated and cooled using a condensing means and/or a substrate of a predetermined shape, and the surface of the document is effectively illuminated, so that image information on the surface of the document can be read with high precision. The present invention relates to a document illumination device.

(Prior Art) Conventionally, light sources emitting a large amount of light, such as fluorescent tubes and cannon tubes, have been used as illumination means for image reading devices such as facsimiles. On the other hand, in recent years, the sensitivity of light-receiving elements such as COD has progressed, and light-emitting elements with a relatively small amount of light emitted, such as multiple L
More and more devices are using a light source configured by arranging EDs in an array.

This is because LEDs do not require an inverter for lighting like fluorescent tubes or xenon tubes, so they can be easily made smaller and lower in cost, and because they do not require high-frequency lighting, they do not generate high-frequency noise. This is because they have advantages such as stable rise characteristics and temperature characteristics compared to fluorescent tubes and cannon tubes.

FIG. 5 is a schematic diagram of a main part of an optical system of a conventional document illumination device using such a strong LED.

In the figure, a document 51 with its image information side facing downward is sequentially conveyed in the direction of the arrow shown in the figure by the conveyance force of a feed roller 52, a discharge roller 53, etc. during reading.

On the way, at point 55 on the document platen glass 54, the LED
The illumination light emitted from the array 56 illuminates the image information surface, and the reflected light from the image information surface forms an image on the surface of a photoelectric conversion element 59 made of a CCD or the like via a mirror 57 and an imaging lens 58. The image information on the document surface is read while converting the output signal from the CCD into an electrical signal in an image processing section (not shown).

In the figure, 56-1 of the LED array 56 is an LED
Substrate 56-A on which chip (light emitting part) 56-2 is mounted
is a condensing means, and includes a condenser lens 56-3 that condenses the illumination light emitted from the LED chip 56-2, and the condenser lens 5.
6-3 from both sides, and these elements are integrally formed from a transparent member.

(Problems to be Solved by the Invention) A conventional document illumination device that uses an LED array as a document illumination light source has the following problems.

The condensing means 56-A formed to surround the LED chip 56-2 is formed by integrating a condensing lens 56-3 and a frame portion 56-4 that supports the condensing lens 56-3. It is configured to extend in the longitudinal direction with respect to the substrate 56-1.

Both ends of the light condensing means 56-A in the longitudinal direction are closed in a bag shape at both ends of the substrate 56-1, as shown in FIG. Both ends 56-5 to - are fixed to the substrate 56-1.

In this way, the condensing means 56-A has a closed structure at both ends in the longitudinal direction, that is, the condensing means 56-A surrounds the LED chip 56-2.
Since the inside of the area formed by A and the substrate 56-1 is sealed, the L placed on the substrate 56-1 when illuminating the original
Heat generated from the ED chip 56-2 and a limiting resistor (not shown) was likely to be trapped inside.

For this purpose, for example, in order to increase the amount of illumination light, the LED chip 56-2
There is a design limit to the method of increasing the amount of illumination by mounting the LED array 56 at high density or by passing a large amount of current through the LED array 56.

Furthermore, if the substrate is made of a material such as aluminum, which has good thermal conductivity, in order to facilitate the dissipation of heat generated from the LED chips and limiting resistors, the entire device becomes expensive, and cost reduction is required. It was a hindrance. In addition, in the manufacturing process, for example, the condensing means 56-A is made of PMMA.
When molding with a transparent resin such as (methacrylic resin), both ends 56-5 of the light condensing means 56-A are attached to the substrate 56-A.
1 and has a closed structure, it is not possible to use a molding method that involves extruding the same cross section, and molding methods using injection methods have limited processing methods, and both have problems in the manufacturing process. , it was difficult to improve productivity.

In order to solve the above-mentioned problems, the present invention provides a light beam emitted from a light emitting means to a light emitting means and/or a substrate in a direction other than the radiation direction of the light beam vertically upward to the substrate, or in a longitudinal direction of the light focusing means. By effectively providing openings for ventilation at both ends, it is possible to cool with one ventilation, and the desired amount of light can be obtained as needed. It is an object of the present invention to provide a document illuminating device with a simple configuration that can be widely adopted in various processing methods such as extrusion molding and injection molding in a five-fold process.

(Upper Stage for Solving Problems) The document illumination device of the present invention includes a light emitting means in which a plurality of light emitting elements are arranged in a row along the longitudinal direction of the substrate on the surface of the substrate;
A document illumination device comprising a condensing lens that condenses a light beam from the light emitting device, and a frame that supports the condensing lens so as to surround the light emitting device from both sides in the longitudinal direction of the substrate. In the apparatus, ventilation is provided at a location other than the radiation direction of the light beam emitted perpendicularly upward to the substrate from the light condensing means and/or the light emitting means on the surface of the substrate, or at both longitudinal ends of the condensing means. It is characterized by having an opening for.

(Embodiment) FIG. 1 is a perspective view of a document illumination device according to a first embodiment of the present invention.

In the figure, l is a substrate having a rectangular shape.

2 is a light emitting means (e.g. λ is an LED array) and includes a plurality of LEs.
It has D chips 2a, and these LED chips 2a are arranged in rows in the longitudinal direction on the substrate 1.

3 is a condensing means, which includes a condensing lens 3-1 for condensing the luminous flux emitted from the light emitting means 2; It consists of a frame portion 3-2 that surrounds and supports the frame portion 3-2, and each of these elements is integrally constructed. Openings 3-3 for ventilation are provided at both longitudinal ends of the condensing means 3.

In this embodiment, with such a configuration, when illuminating a document, air flow is created through the openings 3-3 provided at both ends of the condensing means 3, thereby effectively utilizing the heat generated from the LED chip 2a and the limiting resistor (not shown). The heat is radiated to effectively cool the inside of the region formed by the light condensing means 3 surrounding the light emitting means 2 and the substrate 1.

As described above, in this embodiment, by effectively providing openings for ventilation at both longitudinal ends of the light condensing stage, it is possible to mount the LED chips 2a at a high density in order to increase the amount of illumination light, or to mount the light emitting means. A large amount of current can also be passed through 2, thereby making it possible to easily obtain a desired amount of illumination light and effectively illuminate the surface of the document for reading.

Furthermore, since the shape of the light condensing means 3 is formed with the same cross section in the longitudinal direction, it can be processed by extrusion molding or injection molding, thereby improving productivity.

FIG. 2 is a perspective view of a document illumination device according to a second embodiment of the present invention. In this figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

The difference between this embodiment and the first embodiment shown in FIG. 1 is that ventilation is also provided on the sides of the frame 3-2 that supports the condenser lens 3-1 from both sides in the longitudinal direction of the substrate l, as shown in the figure. opening 3 for
-4 were placed at appropriate intervals.

According to this, the heat generated from the LED chip and the limiting resistor (not shown) can be efficiently radiated, and cooling by ventilation can be further improved.

Note that the shape of the window of the opening 3-4 is specified so that the amount of light irradiated from the light emitting means 2 does not decrease during illumination.

FIG. 3 is a perspective view of a document illuminating device according to a third embodiment of the present invention. In this figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

This embodiment differs from the first embodiment shown in FIG.
Openings 3-4 for ventilation are also provided at appropriate intervals in a part of the substrate 1 on which the ED chip 2a is mounted. This further effectively increases cooling through ventilation.

Note that the shape of the window of the opening 3-4 is specified so that the amount of light irradiated from the light emitting means 2 does not decrease, similar to the second embodiment described above.

As described above, in each of the embodiments, openings for ventilation may be provided at appropriate locations other than the radiation direction of the luminous flux emitted vertically upward from the light emitting means to the substrate, or at both longitudinal ends of the condensing means. This opening structure allows air to flow during document illumination, thereby effectively dissipating heat generated from the LED chips and limiting resistors.

Note that the document illumination device may be configured by combining the second embodiment shown in FIG. 2 and the third embodiment shown in FIG. 3.

Further, the effect can be further improved by using a cooling device or the like to send cold air through an opening (ventilation port).

FIG. 4 is an explanatory longitudinal cross-sectional view of a document illuminating device according to a fourth embodiment of the present invention. In this figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

4-1 and 4-2 are claws of the condensing means 3, and the substrate l
It is held in such a way that it is sandwiched from both sides.

The present embodiment has such a configuration, and the condensing means 3 has openings 3-3 for ventilation at both longitudinal ends of the condensing means 3, as in the first embodiment shown in FIG. This makes it possible to effectively radiate heat generated from the LED chip 2a and a limiting resistor (not shown) during document illumination.

That is, in this embodiment, the shape of the condensing means is formed to have the same cross section along the longitudinal direction. For example, when the light collecting means 3 is formed of a transparent resin such as PMMA (methacrylic resin), since both ends of the light collecting means 3 are open, various processing methods such as extrusion molding or injection molding can be used. be able to.

In addition, in this embodiment, as shown in the figure, since the substrate l is held between the claws 4-1 and 4-2 of the condensing means 3, the LED chip 2a is not illuminated when illuminating the document. Even if there is a difference in the coefficient of thermal expansion between the substrate l and the condensing means 3 due to heat generation, it is possible for both to escape in the longitudinal direction.
This effectively prevents deformation such as warping of the optical member due to heat generated by the ED chip 2a and the like.

Note that the document illuminating device may be constructed by combining this embodiment with the second and third embodiments described above.

(Effects of the Invention) According to the present invention, as described above, the light beam emitted from the light emitting means to the light condensing means and/or the substrate in a direction other than the radiation direction or along the longitudinal direction of the light condensing means By appropriately providing openings for ventilation at both ends of the direction, cooling can be achieved with a single ventilation, making it possible to easily obtain the same effect without using, for example, the aluminum substrate used for heat dissipation in the past. Furthermore, as shown in the first and fourth embodiments, since the shape of the condensing means can be formed with the same cross section in the longitudinal direction, processing methods such as extrusion molding and injection molding can also be widely adopted. As a result, it is possible to achieve a document illumination device with a simple configuration that can also contribute to cost reduction and productivity improvement.

[Brief explanation of the drawing]

1 to 3 are perspective views of document illumination devices according to first to third embodiments of the present invention, FIG. 4 is a vertical cross-sectional explanatory view of a document illumination device according to a fourth embodiment of the present invention, and FIG. 6 is a schematic diagram of a main part of an optical system of a conventional document illuminating device, and FIG. 6 is a cross-sectional explanatory diagram of the conventional document illuminating device. In the figure, l is a substrate, 2 is a light emitting means, 2a is an LED chip,
3 is a condensing means, 3-1 is a condensing lens, 3-2 is a frame portion, 3
-3.3-4 is an opening, and 4-1.4-2 is a claw.

Claims (1)

[Claims] (1) A light emitting means in which a plurality of light emitting elements are arranged in a row along the longitudinal direction of the substrate on a substrate surface, a condensing lens that condenses the light beam from the light emitting means, and a condensing lens that is connected to the substrate. and a frame portion that surrounds and supports the light-emitting means from both sides in the longitudinal direction, the light-emitting means on the light-collecting means or/and the substrate surface being connected to the light-emitting means on the substrate surface. 1. A document illuminating device characterized in that an opening for ventilation is provided at a location other than the radiation direction of the luminous flux emitted perpendicularly upward relative to the light beam, or at both longitudinal ends of the light condensing means.