JP2000151915A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small sized close contact image reader that bas a large luminous quantity, copes with heat generation and possible for high speed reading. SOLUTION: An insulator is used between a light source 1 and a unit 7 to suppress fluctuation in the quantity of emitted light due to an abnormal discharge of the light source 1, and a white thermal sheet is used to suppress fluctuation in the emitted luminous quantity due to heat generation. Since a reflected light of the white thermal sheet 9 is used to increase the emitted luminous quantity, the enhanced performance such as high speed reading and high resolution of the image sensor can be expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image reading apparatus capable of increasing the amount of light and coping with heat generation.

[0002]

2. Description of the Related Art As a configuration example of a light source in a conventional image reading apparatus, there is one disclosed in a document: "Japanese Patent Laid-Open No. Hei 7-17731". The light source disclosed in this document is a linear light source, for example, a xenon fluorescent lamp, a cold cathode fluorescent lamp, or the like. In the case of using such a light source, an insulator is used to shield the electrode in order to discharge it to a unit or the like.

FIG. 3 is a diagram showing a configuration example of a conventional apparatus. In the figure, 1 is a light source composed of, for example, a xenon fluorescent lamp or a cold cathode fluorescent lamp, 2 is a cover glass,
3 is a manuscript. The light transmitted from the light source 1 through the cover glass 2 irradiates the original 3, and the anti-shading light is again transmitted to the cover glass 3
Through the imaging element array 4. Reference numeral 6 denotes a photoelectric conversion element array, and reflected light from the original 3 forms an image on a light receiving surface of the photoelectric conversion element array 6 via the imaging element array 4. Reference numeral 5 denotes a sensor array in which photoelectric conversion element arrays 6 are arranged.

In such a configuration, the light source 1 is fixed to the unit 7 at a portion (not shown), and an insulator 8 such as plastic is provided between the light source 1 and the unit 7. Further, a gap 9 of, for example, 3 mm or more is provided between the light source 1 and the unit 7.

[0005]

However, the above-mentioned conventional apparatus has the following problems. (1) Brightness fluctuates due to a rise in temperature due to heat generation of the light source during lighting. (2) If a cooling fan or the like is provided to prevent heat generation, the size of the device increases. (3) Unless a gap is provided between the light source and its surroundings, abnormal discharge occurs and the amount of irradiated light becomes unstable. (4) If a gap is provided between the light source and the periphery thereof, the size of the device increases.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a small-sized close contact image reading apparatus capable of high-speed reading, which has a large amount of light and can cope with heat generation.

[0007]

For this purpose, in the image reading apparatus of the present invention, an image having a photoelectric conversion element array and an imaging element array arranged in a line, a line light source, and a unit for holding them is provided. In the reading apparatus, an insulator and a white thermal sheet are attached between the line light source and the unit.

In the image reading apparatus, a round bar lens or a cylindrical lens is provided between the light source and the document.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. [Description of First Embodiment] [Description of Configuration] FIG. 1 is a cross-sectional view illustrating the configuration of an image reading apparatus according to a first embodiment. In FIG. 1, reference numeral 1 denotes a light source composed of, for example, a xenon fluorescent lamp or a cold cathode fluorescent lamp, reference numeral 2 denotes a cover glass, and reference numeral 3 denotes an original.

The light transmitted from the light source 1 through the cover glass 2 irradiates the original 3, and the reflected light is transmitted again through the cover glass 3 and passes through the imaging element array 4. Reference numeral 6 denotes a photoelectric conversion element array, and reflected light from the original 3 forms an image on a light receiving surface of the photoelectric conversion element array 6 via the imaging element array 4.
Reference numeral 5 denotes a sensor array in which a photoelectric conversion element array 6 is arranged. Reference numeral 7 denotes a unit, and an insulator 8 and a white thermal sheet 9 are provided between the unit 7 and the light source 1. The insulator 8 has a function of preventing discharge of the light source, and the thermal sheet 9 has a thickness of 0.1 to 1 mm used for a heat radiating device or a heat sink of an IC chip, for example.
And has a function of releasing heat generated from the light source to the outside.

[Description of Operation] Light emitted from the light source 1 passes through the cover glass 2 and irradiates the document 3. The reflected light from the original 3 passes through the cover glass 3 again, passes through the imaging element array 4, and forms an image on the light receiving surface of the photoelectric conversion element array 6. In such an image reading apparatus, an insulator 8 is provided between the light source 1 and the unit 7 to prevent discharge from the light source to the unit 7. Further, a white thermal sheet 9 is provided between the light source 1 and the insulator 8 in order to prevent a change in the irradiation light amount due to the heat radiation of the light source 1. Since the thermal sheet 9 has a function of releasing heat generated from the light source 1 to the unit 7 and the outside thereof, a stable irradiation light amount can be obtained without a temperature rise around the light source 1. Further, since the thermal sheet 9 is white, light from the light source 1 is reflected on the thermal sheet 9 and can irradiate a document.

As described above, according to the present embodiment, the use of the insulator between the light source 1 and the unit 7 makes it possible to suppress the fluctuation of the irradiation light amount due to the abnormal discharge of the light source 1. Further, by using the white thermal sheet, it is possible to suppress a change in the irradiation light amount due to heat generation. Furthermore, since the amount of irradiation light can be increased by using the reflected light of the white thermal sheet 9, performance improvement such as high-speed reading and high resolution of the image sensor can be expected.

[Explanation of Second Embodiment] [Explanation of Configuration] FIG. 2 is a cross-sectional view illustrating the configuration of an image reading apparatus according to a second embodiment. In the drawing, reference numeral 1 denotes a light source composed of, for example, a xenon fluorescent lamp or a cold cathode fluorescent lamp, reference numeral 10 denotes a cylindrical lens or a round bar lens, reference numeral 2 denotes a cover glass, and reference numeral 3 denotes an original.

The light emitted from the light source 1 passes through the cylindrical lens 10 and is condensed, passes through the cover glass 2 and irradiates the original 3. The anti-reflection light again passes through the cover glass 3 and passes through the imaging element array 4. Reference numeral 6 denotes a photoelectric conversion element array, and reflected light from the original 3 forms an image on a light receiving surface of the photoelectric conversion element array 6 via the imaging element array 4. Reference numeral 5 denotes a sensor array in which a photoelectric conversion element array 6 is arranged. Reference numeral 7 denotes a unit, and an insulator 8 and a white thermal sheet 9 are provided between the unit 7 and the light source 1.
Is provided. The insulator 8 has a function of preventing discharge of the light source, and the thermal sheet 9 has a function of releasing heat generated from the light source to the outside.

[Explanation of Operation] Light emitted from the light source 1 passes through the cylindrical lens 10 and is condensed, passes through the cover glass 2 and irradiates the original 3. The reflected light from the original 3 passes through the cover glass 3 again, passes through the imaging element array 4, and forms an image on the light receiving surface of the photoelectric conversion element array 6. In such an image reading apparatus, an insulator 8 is provided between the light source 1 and the unit 7 to prevent discharge from the light source to the unit 7. Further, a white thermal sheet 9 is provided between the light source 1 and the insulator 8 in order to prevent a change in the irradiation light amount due to the heat radiation of the light source 1.

As described above, according to the present embodiment, the use of the insulator between the light source 1 and the unit 7 makes it possible to suppress the fluctuation of the irradiation light amount due to the abnormal discharge of the light source 1. Further, by using a white thermal sheet, it is possible to suppress a change in the irradiation light amount due to heat generation. Furthermore, the amount of irradiation can be increased by utilizing the reflected light of the white thermal sheet 9 and the light can be further increased by condensing the light with a cylindrical lens or a round bar lens. It can contribute to performance improvement such as resolution.

[0017]

As described in detail above, claim 1 is as follows.
According to the invention described in the above, in an image reading apparatus having a photoelectric conversion element array and an imaging element array arranged in a line, a line light source, and a unit that holds them, an insulator is provided between the line light source and the unit. And the white thermal sheet are attached, it is possible to suppress the fluctuation of the irradiation light amount due to the abnormal discharge of the light source and the fluctuation of the irradiation light amount due to the heat generation. Further, since the amount of irradiation light can be increased by using the reflected light of the white thermal sheet, it is expected that the image sensor can be improved in performance such as high-speed reading and high resolution.

According to the second aspect of the present invention, since the round bar lens or the cylindrical lens is provided between the light source and the document, the irradiation light amount can be further increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image reading apparatus according to a first embodiment.

FIG. 2 is a configuration diagram of an image reading apparatus according to a second embodiment.

FIG. 3 is a configuration diagram of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Cover glass 3 Original 4 Imaging element array 5 Sensor array 6 Photoelectric conversion element array 7 Unit 8 Insulator 9 Thermal sheet 10 Cylindrical lens (round bar lens)

Claims (2)

[Claims] 1. An image reading apparatus having a photoelectric conversion element array, an imaging element array, a line light source, and a unit for holding them, which are arranged in a line, wherein an insulator and a white light source are interposed between the line light source and the unit. An image reading apparatus having a thermal sheet attached. 2. The image reading apparatus according to claim 1, wherein a round bar lens or a cylindrical lens is provided between the light source and the document.