JP2866567B2 - Image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, Lee Mejisensa, in particular, reads the image information, regarding contact image sensor for use in facsimile or scanner to change into an electrical signal.

[0002]

As a read method for reading an image such as characters and graphics in the Background of the facsimile or scanner, conventionally, there are an image sensor Yai Mejisensa of CCD type, CCD type image sensor has been the mainstream so far. However, the CCD type image sensor has a limit in reducing the size of the entire reading device.

On the other hand, Lee Mejisensa uses rod lens array without using the reduction optical system as in the image sensor of the CCD type. Therefore, there is an advantage that the size of the reader in the thickness direction can be reduced. Therefore, along with the demand for miniaturization of the reader, the reading method of Lee Mejisensa has increased rapidly.

FIG. 12 is a sectional view of a conventional image sensor manufactured by, for example, Mitsubishi Electric Corporation. In the figure, reference numeral 1 denotes an integral frame, and 2 denotes a fixedly installed bottom surface of a tunnel-like cavity of the integral frame 1. The sensor substrate 3 is a converging lens fixed to the opening side of the integral frame 1. In this conventional example, a rod lens array is used. Reference numeral 4 denotes a light source disposed on the opening side of the integrated frame 1 like the rod lens array 3, and in this conventional example, an LED (light emitting diode) is used.

[0005] Reference numeral 5 denotes a glass plate attached to the opening end of the integrated frame 1, reference numeral 6 denotes a platen, and reference numeral 7 denotes a document which is moved between the platen 6 and the glass plate 5. Reference numeral 8 denotes a sensor provided on the sensor substrate 2, and 9 denotes a connector that is incorporated in the integrated frame 1 and that inputs and outputs external signals.

Next, the operation will be described. As shown in FIG. 12, the light from the light source 4 incorporated in the frame 1 is projected onto the original 7 conveyed by the platen 6 on the glass plate 5,
The reflected light of the reflected text or image information of the original 7 is read by the sensor 8. For example, in the case of a black (character) portion of the document 7, the sensor 8 has a low output (for example, 0 V) because the sensor 8 receives a small amount of light from the light source 4. In the case of a white (no character) portion of the document 7, the sensor 8 receives a large amount of light from the light source 4 and thus has a high output (for example, 3 V). Here, the rod lens array 3 functions as a kind of focusing lens for efficiently transmitting the light from the light source 4 to the sensor 8. A plurality of sensors 8 are usually mounted on the sensor substrate 2 and arranged in a line. The sensor 8 includes a sensor, that is, a shift register for sending out the photoelectrically converted electric signals in order, and an analog switch in addition to the photoelectric conversion function. These electric signals are transmitted to the outside through the connector 9 as black and white information output.

By the way, as in this case, the light source 4 is a block diagram of a Lee Mejisensa shown in FIG. 13, a plurality of LE
D are arranged in a line, and are formed so as to emit light evenly in block units. FIG. 14 is a plan view of the light source 4 and is always disposed at a constant interval (pitch) P.
The light source 4 is a monochromatic light source that uses a yellow-green color having a wavelength of 570 nm. In this wavelength, there is no problem in the case of monochrome characters.
You cannot read green etc. When reading a color image, three color light sources are required. For example, a single light source of red, green, and blue is provided in block units, and three color light sources are formed. Then, an image is read by applying a current.

Each sensor 8 has a group of 64-bit light receiving sections, and is arranged in a row corresponding to each LED. In other words, for the manuscript of A4 size
When the light source 4 a b Mejisensa is composed of 27 pieces of LED, has a light receiving portion of the 1728 bits, the light receiving portions can know the power LED light amount distribution of the of the received light. Light source 4 in a conventional Lee Mejisensa, because it is formed in block units as described above, the light amount distribution of each LED, the light amount distribution of the entire read width by directional or the like, a 27, as shown in FIG. 15 Basically, a large ripple is held for the LEDs arranged in a line.

[0009] Figure 16 is a timing chart of the black-and-white signal output of the conventional Lee Mejisensa receives a signal SI (start signal), with a synchronous of the CLOCK signal,
SIG (monochrome signal output) is output in accordance with the information sequentially read by the sensor 8.

In FIG. 13, the amplifier is a voltage amplifier, which normally amplifies the sensor output by a factor of 10 to 40, and
G.

[0011]

THE INVENTION Problems to be Solved] However, the conventional
Lee Mejisensa, which is configured as described above,
In the case of a monochromatic light source, there is a problem that a color image cannot be read.

Also, there is a problem that the light source cannot be brought close to or close to the document surface due to the ripple.

In order to solve this problem, there is a method of using a single LED over the entire reading width, but it has not been realized because of its large size, high practical cost, and so on. There is also a method of making the pitch (P) of the blocks dense, but they cannot be arranged in a line in reading a color image. Further, the increase in current consumption greatly increases the heat generation of the light source, which makes practical use difficult.

When the distance between the light source and the document surface is increased, the light amount distribution due to the directivity and the like is improved, but there is a problem that the illuminance of the document surface is reduced and the efficiency of the light source is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to prevent a ripple in a light amount so as to make the light amount distribution uniform and to read a color image. Another object of the present invention is to provide an image sensor that can be reduced in size and thickness.

[0016]

In order to achieve the above object, according to the Invention The image sensor according to the first invention is a prismatic transparent body, the document conveyed in the transparent body extraordinary
Notch at one corner perpendicular to the transport direction of the original
And an irradiator having a slit portion for irradiating the original with light from a light source disposed near at least one end of the transparent body, the slit being provided on the surface formed by The irradiating light from the unit is reflected by the document surface, and has a converging optical unit for converging the reflected light, and a sensor for receiving the converging light converged by the converging optical unit. In terms of installation of
The slit is opened in a direction orthogonal to the document conveying direction, and the surface of the slit portion is formed with irregularities in a direction orthogonal to the document conveying direction, and the slit width of the slit portion increases as the distance from the light source increases. It was done.

An image sensor according to a second aspect of the present invention has a first
In the invention according to the above, the slit portion and the light source arrangement portion
The surface of the transparent body except for the light shielding member or the light reflecting portion
It is covered with a material.

An image sensor according to a third aspect of the present invention has a prism
Is a transparent body, and the original conveyed by the transparent body is
Open in a direction perpendicular to the document transport direction
Disposed near at least one end of the transparent body.
Scattered light from the light source
An irradiation body having a slit portion,
Both sides where the light source is not disposed,
A light shielding member or a light reflecting member that covers a part of the surface,
Irradiation light from the slit is reflected by the document surface ,
Focusing optical means for focusing the reflected light; and
A sensor for receiving the more focused light,
One side of the light shielding member or the light reflecting member on the slit side
The slit portion was provided as the distance from the light source increased
Of each ridge line formed by the
It is a digit.

An image sensor according to a fourth aspect of the present invention has a first
Alternatively, in the third invention, the light sources are different from each other.
It is composed of a plurality of light emitting colors.

An image sensor according to a fifth aspect of the present invention has a first
Alternatively, in the third invention, the light source is an end of the irradiation body.
Light is emitted directly from the slit in the dark box
It is stored in a position where it is not ejected.

An image sensor according to a sixth aspect of the present invention has a fifth aspect.
In the invention of the above, the irradiation body, the dark box and the focused light
It integrates learning means.

[0022]

In engaging Louis Mae <br/> Jisensa the present invention having a [action] above configuration, it irradiates the document surface with light from the irradiated body,
The reflected light from the document surface is collected by focusing optics and
And photoelectrically converted to obtain a voltage output. According to the invention
Then, the distribution of the amount of light emitted from the slit part of the irradiation body is
The light source must be in close contact with the original surface because it is uniform
Can be.

[0023]

[Embodiment 1] Hereinafter, a preferred embodiment of the engagement Louis Mejisensa described the invention with reference to the drawings.

In FIG. 1, 11 is a frame, 12 is a sensor substrate mounted and fixed on the bottom surface of the tunnel-shaped cavity of the frame 11, 13 is a rod lens array fixed to the opening side of the frame 11 and used as a focusing lens, 14 Is a glass fiber light source provided as light source means on the opening side of the frame 11.

Here, as shown in FIG. 2, the glass fiber light source 14 is composed of an elongated glass fiber square member 19 having one surface as a light emitting surface, and dark boxes 20 attached to both ends thereof.
It is composed of The square member 19 has a transparent bar portion 19a that totally reflects light from the light emitting means, and a slit portion 19b that is provided on the light emitting surface by partially processing the light emitting surface along the longitudinal direction and emits light to the outside. In this embodiment, two LEDs (light emitting diodes) 21 are arranged in parallel in each dark box 20 as light emitting means.

In this embodiment, as shown in FIG. 1, the glass fiber light source 14 is attached to a glass plate on which a document or the like is placed, or a document support table required for supporting or transporting the document. A key-shaped groove 11a is provided in a part of the support base, and the dark box 20 portion of the glass fiber light source 14 is tightly fixed by being sandwiched between the groove 11a and the light source table 11b disposed below each dark box 20 in the frame 11. I do. Therefore, the upper surface of the glass fiber square member 19 is installed in an open state.

[0027] In addition, Louis Mejisensa 1 put to the present embodiment
Reference numeral 0 denotes a sensor 18 provided on the sensor substrate 12 and an original guide 15 which guides the original 7 conveyed by the platen 6 and which is arranged near the surface of the original 7 which reflects light from the glass fiber light source 14. And

[0028] Next, Louis Mejisensa 1 put to the present embodiment
The operation of 0 will be described.

In FIG. 1, the glass fiber light source 14
Is reflected by the original surface, is focused by the rod lens array 13, and is incident on the sensor 18 of the sensor substrate 12. The light received by the sensor 18 is photoelectrically converted into a black and white signal output, and the black and white signal is processed in the same manner as in the related art. FIG. 3 shows a light quantity distribution of each part of the glass fiber light source 14. As shown in FIG. 2, since the glass fiber light source 14 is provided with the LEDs 21 at both ends, the light amount is reduced from the both ends sequentially to the center, though there is no block variation but there is no block variation. Curve A in FIG.
Curve B shows the case where one is attached to both ends, and curve B shows the case where two are attached.

As described above, ripples can be prevented by mounting the LEDs 21 at both ends of the glass fiber light source 14. The magnitude of the output value of the entire light amount can be changed by the slit width.

In this embodiment, as the distance from the light emitting means, that is, the LED 21 increases, the slit portion 1
9b is formed to have a large width. In this embodiment, since the glass fiber light source 14 has the LEDs 21 at both ends thereof, the slit width W2 at the center is equal to the slit width W at both ends as shown in FIG.
1, the slit width is formed to be larger than W3, and the slit width is gradually reduced from the center to both ends.
A curve C in FIG. 3 is a case where one LED 21 is attached to both ends of the glass fiber light source 14 shown in FIG. 4, and a curve D is a case where two LEDs 21 are attached. As described above, by increasing the slit width W2 at the central portion, the light emission area of the region becomes larger than that at both ends, so that the light amount distribution becomes flat.

FIG. 5 is a side view of a main part of the slit portion 19b shown in FIG. 4, and FIG. 6 is a plan view of the slit portion 19b. Here, the slit portion 19b is formed by slitting a part of the light emitting surface, which is the surface of the glass fiber square member 19 facing the document 7 of the thickness l, into a slit shape, and grinding the entire slit portion or an essential part thereof. It is formed by providing irregularities. In this case, the surface of about 1 μm to 5 μm can be made uneven by selectively treating the square bar 19 with hydrofluoric acid. As shown in FIG. 5, the position of the LED 21,
By appropriately adjusting the slit depth t of the slit portion 19b and the emission angles α and β of the light from the LED 21 to the respective uneven surfaces in the horizontal direction, the scattered light can be emitted from the square member 19 to the outside. Further, the slit widths W1 to W3 with respect to the width W0 of the square member 19 are determined by a computer based on the position of the LED 21 serving as a light source and its directivity so as to emit a uniform amount of light. Then
(1 mm x 7 mm) and the surface roughness.
The amount of light is determined by the dimensions shown in FIGS. 5 and 6 with the center of the optical axis when one LED 21 is used. Also, the portion of the transparent bar portion 19a other than the slit portion 19b is inherently totally reflected and emits little light, but because of unnecessary radiation, its surface is coated with a light shielding member or a light reflecting member. In this embodiment, the silver material is coated on the portions other than the slit portion 19b. These steps are, to be precise, square beams 19
The most accurate method is to coat the entire surface except for both end surfaces with silver material in advance and remove the silver material at the same time when the slit portion 19b is formed. This is because, if the slit 19b is provided first and then coding is performed on a portion other than the slit 19b, the presence or absence of coding at the boundary with the slit 19b becomes a problem.

In this manner, the silver material is removed from the slit 19b.
Coating other than In the range of several mm from both ends of the square member 19, the light emitted from the LED 21 having no directivity is directly emitted from the slit portion 19b, so that the light amount increases. Therefore, it is best to dispose the LED 21 at the back of the dark box 20 so that the light from the LED 21 is not directly emitted from the slit portion 19b and to make the emission of the direct light zero, but it is unnecessary when the effective reading width is small. It is.

The configuration of the unevenness of the slit portion 19b and the manufacturing method thereof are also effective in the embodiments described later.

As described above, the glass fiber light source 14
By mounting the LEDs 21 at both ends of the light emitting device and forming the slit portion 19b as described above, ripples can be prevented and the light amount distribution can be made uniform.

Embodiment 2 FIG. FIG. 7 is a schematic view showing another embodiment of the glass fiber light source 14. The characteristic feature of the second embodiment is that, as shown in FIG. 8, three light sources of a plurality of colors are provided as LEDs as light emitting means to enable color reading. That is, the three light source units 121 having the red, blue, and green LEDs are fitted into the three light source unit connection portions 20a of the dark box 20 provided at both ends of the glass fiber light source 14, and are sequentially turned on in red, blue, and green. The specified light source can be obtained.

By the way, reading of a color image is usually performed by
Although a light source having a wavelength in the entire region such as a white fluorescent lamp and an infrared cut filter are used, in this embodiment, the LED of each color is used.
No infrared cut filter is required because
Further, it is not necessary to provide the sensor 18 with a three-color identification filter for selecting a wavelength from the white fluorescent lamp.

As described above, color reading can be performed by using the three light source units 121 having red, blue, and green LEDs.

By providing a white light source instead of the three light sources, a single light source having a plurality of wavelengths can be obtained. In this case, it is necessary to provide a three-color discriminating filter. However, the color reading light source can be downsized, and is more effective than using a conventional fluorescent lamp.

The three color LED light sources attached to the dark box 20 are set on a printed circuit board so that three red, green, and blue lights are centered on blue. This is because blue has the worst luminous efficiency and is used as a starting point for optical dimensions at the time of design. Of course, the present embodiment is not limited to this arrangement. Each terminal is provided, the common is common, and the number of pins is kept at four. During driving, red, green, and blue lights are sequentially turned on, a one-line color image is read, and signal outputs for each color are sequentially sent out to be color image data. In this case, the luminous efficiencies of red, green, and blue are different from each other, but the output signals of each color are processed by a signal processing circuit to be described later. fundamentally,
Since the adjacent light amount distribution at each reading position is close to zero, there is no problem of chromatic aberration.

In this embodiment, the slit width is continuously changed at the center and both ends of the slit portion 19b. However, when the slit width is the same, the decrease in the amount of light gradually decreasing at the center is obtained. Although it can be corrected by adding a shading correction circuit after reading out the signal output, this is not the gist of the present invention.

Embodiment 3 FIG. FIG. 9 illustrates a C-cut of a part of the glass fiber material 119 constituting the glass fiber light source 14, and a slit 119b is provided in the cut part. The flat portion 120 provided on the upper surface of the square bar 119 is designed to be able to be in close contact with the document support table. Of course, they may be bonded and integrated.

Therefore, the square bar 119 can be fixed to the frame without providing the key-shaped groove 11a in the frame 11 as in the first embodiment.

In FIG. 9, the side surface of the square bar 119 is disposed so as to be in close contact with the rod lens array 113. Alternatively, they may be bonded and integrated. Thus, Louis Mejisensa put to this embodiment, further downsizing,
The thickness can be reduced.

Embodiment 4 FIG. In the above embodiment, the emission light is made uniform by increasing the width of the slit portion as the distance from the LED increases, but in the present embodiment, the width of the slit portion is increased without changing the width of the slit portion. The thickness of the square member is made thinner in accordance with the formula (1) to make the emitted light uniform. As in the above embodiment, if LEDs are provided at both ends of the glass fiber light source, as shown in FIG. 10, as the square member 219 of the glass fiber light source approaches its center, its thickness L2 becomes smaller at both ends. It is formed thinner than the part thicknesses L1 and L3. Reducing the thickness of the central portion reduces the radiation angle at which light from the light source is received, so that light emitted from the slit portion 219b, that is, scattering increases.

As a result, the amount of light emitted from the glass fiber bar 219 can be increased toward the center of the bar 219, as shown in the first embodiment.
As in the case where the slit width is increased toward the center, the light amount distribution can be made uniform.

Embodiment 5 FIG. As described above in the first embodiment, a silver material is used to prevent unnecessary radiation from the
Although coating is performed on the surface other than the surface 9b, the characteristic feature of this embodiment is that, as shown in FIG.
The pattern of the light shielding portion (coded portion) 319d of the transparent bar portion 319a is changed from the LED (not shown) provided at the end of the glass fiber light source without changing the width of the slit portion 319b of the glass fiber square material 319. The less you go, the less. That is, in the present embodiment, as in the above embodiment, if LEDs are provided at both ends of the glass fiber light source, as shown in FIG. 11, the scattered light is more likely to be emitted toward the center of the surface of the square member 319. The structure is to reduce the number

As a result, the light amount distribution can be made uniform, as in the above embodiment.

Embodiment 6 FIG. In the above-described first to fifth embodiments, a square material is used as the glass fiber. However, when the efficiency of the light amount is not important, a circular or semicircular glass fiber may be used.

Embodiment 7 FIG. In the first to fifth embodiments, the glass fiber is used as the material constituting the light source. However, when the light quantity efficiency is not limited, the same effect can be obtained even with a plastic material using an acrylic resin or the like.

[0051]

According to the present invention, since the slit width of the slit is increased as the distance from the light source increases, the distribution of the amount of light emitted from the slit can be made uniform. In particular, the slit portion, Katsu Resona faces the original transparent body
Is arranged on a surface formed by cutting out a corner perpendicular to the original conveyance direction, so that the surface facing the transparent original can be in close contact with the original support table, so that the size and thickness can be reduced. be able to.

Further , the slit portion and the portion where the light source is provided are removed.
Cover the surface of the transparent body with a light shielding member, etc.
Light is emitted only from the
Can be released.

Further, the slip of the light shielding member or the light reflecting member is performed.
As one side on the side of the
The light source is sandwiched between the surface provided and the surface provided with the transparent slit.
Move away from each ridge formed by both sides that are not arranged
So that the slit width does not need to be changed
Release from the slit as in the case of adjusting the slit width.
The distribution of the amount of emitted light can be made uniform.

Also, a plurality of colors can be emitted.
Or use multiple long single light sources to reduce the size of the device.
To read color images while maintaining
You.

Further , a light source is provided at a dark end provided at an end of the irradiation body.
Stored in a position where light is not emitted directly from the slit in the box
The distribution of the amount of light emitted from the slit
Uniformity can be achieved.

Further , the irradiation body, the dark box and the focusing optical means are integrated.
The image sensor has been made smaller and thinner.
be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing first and second embodiments of a contact imager according to the present invention.

FIG. 2 is a view showing a glass fiber light source in the first embodiment.

FIG. 3 is a diagram showing a light quantity distribution of a glass fiber light source in the present embodiment.

FIG. 4 is a diagram showing another glass fiber light source in the first embodiment.

FIG. 5 is a side view of a main part of a slit portion of the contact imager according to the present invention.

FIG. 6 is a plan view of a main part of a slit portion of the contact imager according to the present invention.

FIG. 7 is a view showing a glass fiber light source in a second embodiment of the contact imager according to the present invention.

FIG. 8 is a diagram showing a light source according to a second embodiment.

FIG. 9 is a view showing a glass fiber light source and a rod lens array in a third embodiment of the contact imager according to the present invention.

FIG. 10 is a view showing a glass fiber square in a fourth embodiment of the contact imager according to the present invention.

FIG. 11 is a view showing a glass fiber square material in a fifth embodiment of the contact imager according to the present invention.

FIG. 12 is a cross-sectional view of a conventional contact image sensor.

FIG. 13 is a block diagram of a conventional contact image sensor.

FIG. 14 is a plan view of a conventional light source.

FIG. 15 is a diagram showing a light quantity distribution of a conventional light source.

FIG. 16 is a diagram showing operation timing of a conventional contact image sensor.

[Explanation of symbols]

 Reference Signs List 11 frame 11a groove 12 sensor substrate 13, 113 rod lens array 14 glass fiber light source 18 sensor 19, 119, 219, 319 square material 19a, 319a transparent bar portion 19b, 119b, 219b, 319b slit portion 20 dark box 20a 3 light source unit connection portion 121 3 light source unit l thickness of glass square t depth of slit W1, W2, W3, Wn slit width W0 width of glass fiber square

Claims (6)

(57) [Claims] 1. A prismatic transparent body,SaidTransparent
Look at the conveyed originalMikatsunoPerpendicular to the original transport direction
ToArranged on the surface formed by cutting out one corner
AndNear at least one end of the transparent body
A light source for irradiating the original with light from the light source provided.
An irradiation body having a lit part;,  Irradiation light from the slit portion is reflected by the document surface,
Focusing optical means for focusing the reflected light;,  A section for receiving the focused light focused by the focusing optical means.
And,  Has,  The slit portion of the transparent bodyIn terms of installation,
Opened in a direction perpendicular to the paper transport direction, The slit
On the surface of the document in the direction perpendicular to the direction of conveyance of the original
Is formed, and the slit width of the slit portion is adjusted to the light width.
The feature is that it increases as you move away from the source
Image sensor. 2. A portion where said slit portion and said light source are disposed.
The surface of the transparent body except for a light shielding member or a light reflecting member
2. The image according to claim 1, wherein the image is coated with
Disensor. 3. A prismatic transparent body, wherein the transparent body
The surface facing the document to be conveyed is perpendicular to the conveyance direction of the document.
At least one of the transparent bodies opened in the direction
Scattering light from a light source disposed near the end of the
An irradiator having a slit for irradiating a document, and the light source sandwiching a surface of the transparent body provided with the slit.
A light shielding member that covers a part of both sides where no
Is a light reflecting member, irradiation light from the slit portion is reflected by the document surface,
Focusing optical means for focusing the reflected light, and a sensor for receiving the focused light focused by the focusing optical means.
And the slit of the light shielding member or the light reflecting member
As one side of the unit is moved away from the light source,
Away from each ridge line formed by the surface on which the
An image sensor characterized in that it is provided so as to be able to operate. 4. A light source according to claim 1, wherein said light sources emit different colors.
4. The method according to claim 1, wherein the first and second parts are constituted by a plurality of pieces.
An image sensor according to any one of the above. 5. The light source is provided at an end of the irradiation body.
Light is not emitted directly from the slit in the dark box
4. The device according to claim 1, wherein the device is stored in a position.
An image sensor according to any one of the claims. 6. The illuminator, the dark box, and the focusing optics.
6. The image according to claim 5, wherein the means are integrated.
Sensor.