JPS63138870A - Optical device - Google Patents

Abstract

PURPOSE:To attain a stable picture reading with high quality by using a light shielding member so as to shield the scattered light except the reflected light from an object focused by a focus means. CONSTITUTION:The read section is provided with the ceiling plate 21 and a frame 27 formed in its cross section as nearly pi-shape by the said ceiling plate 21. A driving board 43 mounted with an amplifier circuit amplifying a signal proportional to the luminous quantity and receiving a light by a photodetector section 39 and a scanning circuit to drive the photodetector section 39 is provided between an image sensor 41 and a ceiling plate 21. A light shielding member 50 of which cross section is in the inverted-L shape is fixed along the side face of the rod lens array 31 and the bottom face of the ceiling 21 by an electric conductive adhesives. The light shielding member 50 is constituted by an electric conductive tape such as copper foil or the like to prevent the scattered light except the reflected light from the original read face focused by the rod lens array 31 among the radiated lights of a xenon discharging tube 29 from being made incident on the photodetector section 39 from a light guide part 37.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides an optical device that is particularly useful when applied to an image reading vlW1 that is connected to a personal computer and reads an original image according to commands from the personal computer, for example. Regarding.

(Prior art) This type of device is of course used as an image scanner for facsimiles and image file devices, but it is also connected to a personal computer and used to input original images such as illustrations and edit them on the display. is being done. Therefore, as personal computers become smaller, there is an increasing demand for smaller devices.

In the image reading device conventionally used in the above device,
For example, a fluorescent tube is used as a light source, and of the light emitted from the fluorescent tube, the reflected light from the document reading surface is focused by a rod-shaped lens array, and the focused reflected light is converted into a read signal by an image sensor ( photoelectric conversion) and output.

However, in the above-mentioned conventional image reading device, the source light is focused by the rod-shaped lens array. 1) Scattered light (stray light) other than the light reflected from the reading surface enters the light-receiving section of the image sensor, resulting in a decrease in image reading accuracy, and this problem becomes more pronounced as the optical system becomes smaller. .

(Problems to be Solved by the Invention) As described above, in the conventional image reading device described above, scattered light enters the light receiving section of the image sensor and becomes noise, making it impossible to read a stable image. There was a problem. Furthermore, when the optical system is made smaller, the amount of scattered light incident from the light receiving section increases, making it impossible to achieve miniaturization of the optical system and the device.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical device that enables stable image reading without being affected by noise.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, there is provided a holding means for holding an object, and an illumination device that irradiates light toward the object held by the holding means. means, a condensing means for condensing the light emitted from the illumination means and reflected from the object, and a condensing means disposed opposite to the holding means via the condensing means and the illumination means, and a condensing means for condensing the light emitted from the illumination means and reflected from the object; a first light blocking means for blocking light;
A second light shielding means extends continuously from the first light shielding means toward the holding means and cooperates with the first light shielding means to accommodate the light condensing means and the illumination means. a frame, and a third frame that blocks light leakage from the illumination means to the light condensing means, which is housed in the frame.
A light shielding means.

(Function) In the present invention, for example, according to the embodiments shown in FIGS. 1 and 3, the irradiated light from the light source 29 is C-reflected on the document reading surface, and is focused by the rod-shaped lens array 31 as reflected light.

In the present invention, the light shielding member M1. Second and third light shielding means 2
1.23.25 and 50 prevent light other than the above-mentioned focused light from entering the light receiving section, thereby preventing it from being mixed into the read signal as 91 sound.

(Embodiment) FIG. 1 shows a side sectional view showing the structure of an embodiment of the device according to the present invention.

This embodiment is based on Seiko's device main body 100 and this device main body 10.
Paper feeding unit 200. It includes a reading section 300 and a paper ejecting section 400. Document insertion slot 1 of device main body 100
The original inserted from
After the original document surface image information is read by the reading section 300, the document is discharged to the outside of the apparatus main body 100 by the paper discharging section 400.

The paper feed section 100 includes a first document detector 3 that detects an inserted document, a paper feed roller 5 that is driven when the first document detector 3 detects insertion, and a feed roller 5 that is driven when the first document detector 3 detects the inserted document. A second document detector 7 is provided to detect the document.

The paper ejecting section 400 also includes a transport roller 9 that transports the scanned original, and a third original detector 1 that detects the transported original.
1 and a paper ejection roller 13 for ejecting the transported document to the outside of the apparatus.

Then, the paper feed roller 5. The conveyance roller 9 and the paper discharge roller 13 are simultaneously driven by a step motor 15 via a belt 17. The step motor 15 is driven and controlled so as to start at the document detection timing of the first document detector 3, and to stop after a predetermined period of time has elapsed after the end of the conveyed document leaves the third document detector 11. ing.

Each of the rollers 5, 9, and 13 is formed of a rubber roller at the lower stage and a plastic roller at the upper stage, and each of the upper plastic rollers is supported on a shaft so that it can move slightly in the vertical direction. Smooth document transport is possible without being affected by the

FIG. M2 is a plan view of the reading section 200, and FIG. 4 is a side view taken in the direction of arrow A in FIG.

As shown in FIGS. 1 and 3, this reading section 20.0 includes a top plate (first light shielding means) 21 and a parallel side plate (second light shielding means) provided perpendicularly to the top plate 21. 23 and 25, the frame 27 has a substantially π-shaped cross section. This frame 27 is anodized and electrically insulated.

A xenon discharge tube 29, which will be described later, is positioned and fixed in the storage space within the frame 27. Also, frame 27
A rod-shaped lens array 31 is attached to one side plate 23, and the light reflected from the document reading surface out of the light emitted from the xenon discharge JR29 is focused. A compression spring 33 is provided between this rod-shaped lens array 31 and the top plate 21.
is loaded, and the rod-shaped lens array 31 is
1 can be moved up and down to adjust the focal length. A light guiding section 37 is opened in the top plate 21 directly above the rod-shaped lens array 31.

Further, an image sensor 41 is provided on the top plate 21 of the frame 27 so that the light receiving element section 39 is located at the light guide section 37 . This image sensor 41 is a contact-type amorphous silicon image sensor, and has an original width (A
1728 light receiving elements 39 in the same length as 4 sizes)
are arranged, and document surface information can be read at a pixel density of 8 lines/am. Therefore, fast response is possible,
Furthermore, since it is a close contact type, it is possible to downsize the device.

Further, between the image sensor 41 and the top plate 21, a scanning circuit for driving the light receiving element section 39 and a light receiving element 81S are provided.
A driving board 43 is provided with an amplifier circuit mounted thereon, which receives light at 39 and amplifies an analog signal proportional to the amount of light.This board 43 and the light receiving element part 39 are made of conductive rubber on the lower side and insulated on the upper side. Support body 4 having a two-layer structure of rubber
They are electrically connected via 5. Furthermore, this board 43 is connected to a harness connector 47, through which driving power is supplied and input/output of M90 signals and image signals are performed. These image sensors 41. The drive board 43 and the support body 45 are covered by an upper cover 49.

Further, a light shielding member (third light shielding means) 50 having an inverted cross section is provided along the bottom surface of the top plate 21 and the side surface of the rod-shaped lens array 31.
is fixed with conductive adhesive. This light shielding member 5
0 is composed of a conductive tape such as copper foil, and the scattered light (stray light) other than the reflected light from the document reading surface focused by the rod-shaped lens array 31 out of the light irradiated by the xenon discharge tube 29 is directed to the light guide section. 37 to the light receiving element section 39 is prevented, and Nl& waves and static electricity are removed.

On the other hand, a glass plate 5 is provided in the opening 51 of the π-shaped frame 27.
3 is attached by a fixing member 55. This glass plate 53 serves as a moving path for the original, and is made of transparent glass with excellent transparency.

As shown in FIG. 1, a reference color correction plate 61 is in surface contact with this glass plate 53, and this reference color correction plate 61 is attached upwardly with a weak elastic force by a pair of compression springs 57 and 59. Forced. This reference color correction plate 61 is a white plate for white reference correction to correct image signals including shading distortion noise from the light receiving element section 39 and variations in pixels. It has a special coating that makes it strong. The start of reading the white reference correction data is based on a timing signal from the first document detector 3 that detects the document.

FIG. 4 shows the reading state of a thin original, and FIG. 5 shows the reading state of a thick original.

As shown in both figures, an original 60 is held between a glass plate 53 and a reference color correction plate 61, and an image thereof is read. At this time, the original 60 is lightly pressed against the glass surface by the compression springs 57 and 59, and moves up and down depending on the thickness of the original 160, so the optical path length of the xenon discharge tube 29, the original reading surface, and the rod-shaped lens array 31 is It is always constant without being affected by the thickness of 60, and stable image reading is possible.

Further, since the original 60 is in tight contact with the surface of the glass plate 53 and no lifting occurs on the original, the optical path length is always stable and there is no worry that the read image will be blurred.

FIG. 6 is a block diagram of the xenon discharge tube, and FIG. 7 is a diagram of the xenon discharge tube 1! FIG. 3 is an external configuration diagram of a tube.

This xenon discharge tube 29 has xenon gas sealed inside the tube, and has a 20kH2
A high frequency voltage of ~30 kHz is applied to cause a cold cathode discharge to emit light. In this example, the tube was made by Toshiba Corporation and had a diameter of φ5, 81 m.

A low power consumption xenon discharge tube with an emission wavelength of 546 nl is used.

Further, an auxiliary electrode 75 is attached to the tube surface in the longitudinal direction of the xenon discharge tube 29. This auxiliary electrode 75
is provided to attract electrons emitted from the electrodes 71 or 73 for quick and reliable discharge.This ensures straight-line stability of the positive column not only at the start of lighting but also during continued lighting, and the document surface Stability of illuminance is ensured.

Further, an aperture 77 is provided on the tube surface, and the discharge tube 2
The aperture angle of 9 is maintained at approximately 60 degrees.

The discharge tube cover 78 supports the discharge tube 29, protects the auxiliary electrode 75, and blocks irradiation from the back side of the discharge tube 29. Note that 81 and 83 are holders for fixing the discharge tube 29 and the discharge tube cover 78.

Furthermore, a high frequency voltage of 20 to 30 kHz is applied to each electrode 71, 73 and the auxiliary electrode 75 from the power supply device via a cable 79, but the cable 79 of this embodiment is composed of a shielded cable, and there is no wire on the core wire. A wire coated in a net shape is grounded to the outside of the device. This prevents the generation of radiated noise from the cable 79 and avoids affecting peripheral circuits and signal cables.

In the above configuration, when a document is inserted into the apparatus main body 100 from the document insertion slot 1 along the manual feed guide 2, the first
The document detector 3 is activated and detects that the document has been inserted into the main body 100 of the apparatus. As a result, the xenon discharge tube 2
9 lights up, and the color reference correction process of the reference color correction plate 61 is started.

When the reference color correction plate 61 finishes reading the white reference correction data, a read start ready signal is transmitted to an external device such as a personal computer. When a reading start command transmitted from an external device is received in response to this, the step motor 15 starts rotating, and each of the rollers 5, 9, and 13 rotates at the same speed.

The original is conveyed by the paper feed roller 5, and the second original detector 7 is activated. As a result, the time from the activation of the detector 7 to the original reading position aIC is measured.

When the document reaches the reading position IC, the irradiated light from the xenon discharge tube 29 is reflected on the document, enters the rod-shaped lens array 31, and forms an image of the document on the light receiving element section 39 of the image sensor 41. Then, the image sensor 41 performs photoelectric conversion and outputs an image signal corresponding to the reflected light to an external device.

The original that has been read is transported by the transport roller 9, and the third original detector 11 is activated. The end of the manuscript is the third
When the document is removed from the document detector 11 and the third document detector returns to its original state, the discharge tube 29 turns off, and when the document is removed from the paper ejection roller and is ejected to the outside of the apparatus, the step motor 15 stops. The document reading process ends.

As explained above, according to this embodiment, the frame 27 having a π-shaped cross section is formed, the xenon TI tube 29 and the rod-shaped lens array 31 are disposed within the frame 27, and the top plate 21 is disposed within the frame 27. Image se on top.

The configuration is such that a sensor 41 is disposed.

Therefore, the optical system is integrated and simplified, making it possible to downsize the optical system and, in turn, downsize the entire device.

In addition, these xenon discharge tubes 29. Positioning between the 1I-shaped lens array 31 and the image sensor 41 is facilitated, and positioning workability is improved, positioning accuracy is improved, and image reading accuracy is improved.

Further, the frame 27 is anodized and blocks radiation noise generated from the xenon discharge tube 29, thereby preventing malfunction of peripheral logic circuits and noise from entering the signal cable.

Further, particularly according to this embodiment, a light shielding member 50 having an inverted cross-section is provided along the bottom surface of the top plate 21 and the side surface of the rod-shaped lens array 31, so that light other than light reflected from the document reading surface is blocked. Scattered light is prevented from entering the light receiving element section 39 via the light guide section. Further, even if the optical system is made smaller, the incidence of scattered light can be prevented, so the apparatus can be made smaller.

In addition, since the light-shielding member 50 is made of a conductive tape such as copper foil, it absorbs the radiant noise and static electricity generated when the xenon discharge tube 29 discharges, thereby preventing peripheral circuits and signal cables caused by radiant noise and static electricity. adverse effects on can be avoided.

In the above embodiment, an image reading device using the image sensor 41 was explained as an example, but the present invention is not limited to the above embodiment. It can also be applied as

[Fl Ming's effect IJ! ] As explained above, according to the present invention, the light shielding member blocks out scattered light other than the reflected light from the object focused by the light focusing means.

Therefore, it is possible to prevent scattered light from entering the condensing means, and the m-sound is not mixed into the image reading signal, so that an optical device capable of stable and high quality image reading can be ensured.

[Brief explanation of the drawing]

1 is a configuration diagram of an umbrella body of a device according to the present invention, FIG. 2 is a plan view showing the configuration of a reading section, FIG. 3 is a sectional view taken in the direction of arrow A in FIG. 2, and FIG. 5 and 5 are explanatory diagrams showing the reading process of thin and thick originals, respectively, FIG. 6 is a sectional view showing the configuration of a xenon discharge tube, and FIG. 7 is a perspective view showing the external configuration of the xenon discharge tube. . 100... Apparatus main body 200... Paper feeding section 300... Reading section 400... Paper ejection section 21... Top plate (first light shielding means) 23.25... Side plate (second Light shielding means) 27... Frame 29... 3. Light shielding means) 53...Glass plate 61...Reference color correction plate

Claims (5)

[Claims] (1) Holding means for holding an object; Illumination means for emitting light toward the object held by the holding means; and condensing light emitted from the illumination means and reflected from the object. a light condensing means; a first light shielding means disposed opposite to the holding means via the light condensing means and the illumination means to block light from the illumination means; a frame having a second light shielding means extending in the direction and cooperating with the first light shielding means to house the light condensing means and the illumination means; and third light shielding means for blocking light leakage from the light illumination means to the light condensing means. (2) The optical device according to claim 1, wherein the frame and the third light shielding means are made of a conductive member. (3) The optical device according to claim 2, wherein the third light shielding means is formed of a conductive tape. (4) The optical device according to any one of claims 1 to 3, wherein the third light shielding means is bonded to the frame. (5) The optical device according to claim 4, wherein the adhesive is a conductive adhesive.