JPH03174867A - Optical picture reader - Google Patents

Abstract

PURPOSE:To guarantee picture reading with high picture quality and less effect of an external light by tilting a path of a sight window to an image sensor and causing irregularly reflected light from an external light from the sight window at a high luminous quantity at the side opposite to the image sensor. CONSTITUTION:A sight window path from a sight window 13 opened to a housing 2 to a picture input section 5 is formed in a direction opposite to a lead path of a picture reflection light (a) made incident in an image sensor in a plane view. Thus, even when external light made incident in the inside of the housing 2 form the sight window 13 is reflected irregularly in a pattern to be read, the luminous quantity distribution of the reflected light is strongest at the side of a light source 19 and the luminous quantity returned in the lead path direction of the picture reflected light (a) is comparatively weak. Thus, the effect by the external light is minimized and the picture read with high picture quality is warranted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical image reading device, and in particular to an optical image reading device that is connected to an image processing device such as a word processor or a personal computer, and is used to manually read image information such as text, pictures, and photographs. The present invention relates to optical image reading devices such as hand scanners (Image League).

[Conventional technology]

2. Description of the Related Art Recently, image processing devices such as word processors equipped with hand scanners that can easily input images have appeared.

This hand scanner moves light from a light source in the sub-scanning direction on the document surface while irradiating the document surface through a reading aperture formed on the bottom of the housing, and reflects light from the document surface through a reflecting means such as a mirror. CCD (Charge Co.
The reflected light is inputted to an image sensor such as an uploaded device, and the reflected light is converted into corresponding image data.

Generally, such image scanners have a structure that allows the reader to visually confirm the read portion of the image original that is hidden in the reading section of the scanner during an image reading operation.

Furthermore, in such an image scanner, the width of the housing in the main scanning direction (direction perpendicular to the sub-scanning direction) is formed to a size that can be easily held with one hand, so that stable scanning of the document surface can be performed. be.

[Problems to be Solved by the Invention] However, all conventional hand scanners have factors that not only make it difficult to accurately align the read image portion, but also reduce image reading accuracy.

For example, as shown in Figure 4, some image scanners have a viewing window for viewing the reading position located directly above the reading point of the document between the light source and the image sensor. External light that enters the scanner housing through the viewing window intervenes as a noise component in the reflected light from the image plane caused by the illumination, and enters the image sensor, and the expected image reflected light is affected by the external light. Significantly reduces image reading accuracy. In addition, if the light source and image sensor are arranged in a symmetrical optical axis relationship with respect to the reading point, when reading an image on a glossy surface with good surface reflection, most of the illumination from the light source will be reflected back, making it difficult to read the image. There are disadvantages such as disabling or distorting the read image.

Furthermore, as shown in FIG. 5, in conventional optical image reading devices, the width of the housing in the main scanning direction is such that it can be held with one hand. The width of the reading aperture formed along the width of the document is limited, and the width of the document that can normally be read is also limited to, for example, about 55 mm.

[Purpose of the invention]

The present invention has been made in view of the above, and while making it extremely easy to visually recognize the image to be read, external light entering through the viewing window has almost no effect on the image reflected light, ensuring high-quality image reading. Another object of the present invention is to provide an optical image reading device that ensures a long reading width of an image document to be read in the main scanning direction, and has excellent operability of the housing in the sub-scanning direction.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

As shown in Figures 1 to 3, a hand scanner 1 is used for inputting images into word processors and computer computers.
The housing 2 allows input of images as wide as possible, and is designed to be easy to grip. The portion 3 (first portion) is divided into a substantially T-shape.

Furthermore, stepped portions 7 and 9 are formed on the left and right sides in the sub-scanning direction between the grip 3 and the image input section 5.

These stepped portions 7.9 are located at different levels from each other in the sub-scanning direction, so that when the grip 3 is gripped, the thumb comes into contact with the stepped portion 7 and the index finger comes into contact with the stepped portion 9.

Inside the housing 2, there is housed a mechanism for optically picking up images such as characters or figures drawn on the image document P to be read. This mechanism includes a light source 1 for illuminating a reading aperture 11 of an image document P.
9, a reflecting means 21 which is located directly above the reading opening 11 and changes the optical path of the image reflected light from the image original P in a direction parallel to the original P; and an image reflected light sent through the reflecting means 21. It consists of a photoelectric conversion element such as an image sensor that receives light and converts it photoelectrically, for example, a CCD 25 (line sensor).

Image reading here employs a line scanning method in which the reading area of a given image document is conceptually divided into a plurality of scanning lines and an image is captured for each scanning line.

That is, the image is read while moving the scanner along the surface of the image document. Therefore, the reading opening 1
1 is located on the bottom surface of the housing 2 located at the image control section 5,
It has a linear opening at least in the width direction and the main scanning direction (vertical direction in FIG. 1). This reading opening 11 is preferably closed with a transparent plate.

A light source 19 that illuminates the narrow reading aperture 11
Although various lamps or light emitters can be used as the light emitting device, this embodiment uses an LED array in which a plurality of light emitting diodes (LEDs) are arranged in a line. This LED array light source 19 can be driven with low power consumption, can emit light with a relatively uniform amount of light over the entire illumination area, and is small and lightweight, which is advantageous for this type of handheld device. , what type, configuration,
A light source of a luminescent color may be used, and the present invention is not particularly limited to these.

The light source 19 is arranged at a position that illuminates the reading opening 11 diagonally from above and in front.

A reflection plate 21 provided directly above the reading aperture 11 illuminated by the light source 19 has a total reflection mirror surface, and has a mirror surface that reflects the original
It is tilted at an angle of 5°, so that only the vertically reflected component of the reflected light a from the reading aperture 11 is totally reflected in the horizontal direction and guided to the image sensor 25 located at the rear.

The image light processing section is fixed inside the grip section 3, and includes a condenser lens 23 that guides the image reflected light a to the image sensor 25.
It is equipped with

The condensing lens 23 connects the image sensor 25 from the reflecting plate 21.
It is placed in the optical path of the reflected light a that reaches the image original P.
The light reflected from the reading aperture 11 is imaged on the image sensor 25 with a width narrower than the width of the reading aperture 11.

C
A CD line sensor is preferred. CCD line sensor 1
Each cell corresponds to one pixel of an image read out for each scanning line, and the pixel light of each cell is photoelectrically converted and output.

13 is a viewing window provided on the upper surface of the housing 2. This viewing window 13 is provided at a position displaced from directly above the reading opening 11 to the rear, that is, toward the image sensor 25 side. Since the viewing window 13 is displaced rearward with respect to the reading opening 11, the hole leading to the reading opening 11 is inclined and arranged to avoid at least the reflection plate 21. Therefore, when the scanner is viewed diagonally from above and behind, the viewing window 13 and the reading opening 11 are aligned and can be seen through. Furthermore, since the viewing window 13 is tilted in the opposite direction to the image sensor 25, a small amount of external light that passes through the viewing window 13 and hits the document P is reflected in the opposite direction to the image sensor 25. However, the intended image reflection light is not affected much.

That is, since the viewing path from the viewing window 13 provided in the housing 2 to the image input section 5 is formed in the opposite direction in plan view from the path of the image reflected light a that enters the image sensor, Even if external light entering the inside of the housing 2 is diffusely reflected by the screen to be read, the light intensity distribution of the reflected light is strongest toward the light source 19 side, and the amount of light returning in the direction of the path of the image reflected light a is relatively weak. The effect of light is minimized.

Furthermore, by arranging the viewing path inclined toward the image sensor 25 so as to face the line of sight of the operator in normal use of the hand scanner 1, the image to be read through the viewing window 13 can be easily viewed and recognized.

The housing 2, which forms the external appearance of the scanner, is substantially shielded from light except for the reading opening 11 and the viewing window 13.

The reading opening 11 formed on the lower surface of the housing 2 is formed wider than the grip portion 3 of the housing 2 in the main scanning direction and the width direction, ensuring a long reading width that is not limited by the width dimension of the grip portion 3. It becomes possible to do so.

Furthermore, since the viewing window 13 provided on the top surface of the housing 2 is provided corresponding to the image input section 5 of the housing 2, it is also possible to provide a viewing window with a dimension that approximately corresponds to the width dimension of the reading opening 11. This makes it possible to easily see the entire area in the main scanning direction of the image document to be read.

Reference numeral 17 denotes a rotating member, such as a roller, for smoothly moving the scanner in the sub-scanning direction (rightward in FIG. 1). This roller 17 is formed by recessing the bottom surface of the housing 2 inward to form a roller cover. Further, the roller 17 is connected to a detection means that updates the scanning line in synchronization with the fixed amount movement in the sub-scanning direction when reading the document. This detection means includes a transmission member for transmitting the rotation of the roller 17, for example, a gear 29.31 of - or more, a disk member 35 that rotates in synchronization with the rotation of the roller 17 by the gear 29.31, and a constant rotation of the disk member 35. The rotation detection member 37 detects the rotation amount or rotation angle.

The disk member 35 has a large number of radial pores on its circumferential surface, and is formed by interposing the disk member between a photocoupler or a photointerrupter used as the rotation detecting member 37. As a result, the rotation detecting member 37 outputs a sub-scanning pulse signal every time the disk member 35 rotates by a certain amount.

Furthermore, the detection means constituted by the transmission member such as the gear 29, 31, the disk member 35, and the rotation detection member 37 detects the image reflected light a formed in the housing 2 from the reflection plate 21 to the condenser lens 23. The reflected light a is a region defined by both end portions that do not block the optical path, are outside in the width direction of the reflected light a, and set the length of the reading aperture 11 in the width direction with respect to the sub-scanning direction. It is provided in the inner area in the width direction.

Further, the disk member 35 is provided on the downstream side of the gear 29.31 in the sub-scanning direction and on the inner side in the width direction of the reflected light a. This makes it possible to position the rotation detection member 37 further inward in the width direction of the reflected light a, making it possible to prevent the housing 2 from increasing in size, especially in the width direction.

The control board 27 has, for example, three stages (a, standard,
A brightness switch 39 is provided to change the brightness to light, and a CCD 2 is also provided on the control board 27 (not shown below).
A circuit for driving 5 is provided.

This circuit includes an oscillation circuit, a counter circuit, a CCD output circuit, a flip-flop circuit, and a decoder, and one terminal of the counter circuit becomes high level H when counting of the number of invalid photosensors and no photocells is completed. Further, the other terminal goes to a high level H when the number of valid images is counted after the number of invalid photocells and no photocells has been counted.

In other words, the counter circuit counts, and when the dummy number is counted, the other terminal becomes high level H. Next, the effective area is counted, and when the count is over, one terminal becomes high level H. , the output is synchronized with the line start signal.

If this output is ANDed with a reset pulse, a sample-and-hold signal, and an image output, it can be output as a counter pulse, a write signal, and an image signal.

The flip-flop circuit and the AND circuit have a function of creating a line start signal using the sub-scanning signal, the transfer gate signal, and the output of the decoder.

〔effect〕

As explained above, according to the present invention, since the viewing path is inclined toward the image sensor side, the diffusely reflected light of outside light from the viewing window shows a high light amount on the side opposite to the image sensor, and therefore, the influence of outside light It is possible to guarantee high-quality image reading with less noise.

Further, it is possible to provide an optical image reading device that can ensure a long reading width of an image document to be read in the main scanning direction, and has excellent operability of the housing in the sub-scanning direction.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are cross-sectional views illustrating an embodiment of the present invention, and FIGS. 4 and 5 are explanatory views illustrating a conventional technique. Explanation of symbols 1...Hand scanner 11...Reading aperture 17...Roller 19...LED array 23...Condensing lens 27...Control board

Claims (1)

[Scope of Claims] A housing having a reading opening formed in the bottom surface along the main scanning direction, a light source provided in the housing that illuminates an image reading portion on an image surface to be read, and a light source provided in the housing that illuminates an image reading portion on the image surface to be read; a reflecting means provided within the housing that reflects the image reflected light; and an image sensor provided within the housing that receives the image reflected light from the reflecting means and converts the image reflected light into corresponding image data. and a rotating member that rotates as the housing moves in the sub-scanning direction. and a second part wider in the main scanning direction than the first part, the second part being on the upstream side of the housing in the sub-scanning direction, and the first part being on the upstream side of the housing in the sub-scanning direction. The light source, the reflecting means, and the reading aperture, which is wider in the main scanning direction than the width of the first part, are arranged on the downstream side in the sub-scanning direction, and in the second part of the housing. and a viewing window is provided on the upper surface of the housing of the second part, extending from substantially directly above the reading opening toward the image sensor, and at least at a position partially offset from the reading opening; An optical image reading device characterized in that an aperture and the viewing window form a viewing path that is inclined toward the image sensor.