JP2000083138A - Image reader and light emitting element array for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element array that emits a light with sufficient intensity to a light receiving section without increasing number of light emitting elements and to provide the image reader using the light emitting element array. SOLUTION: Since parts of metallic wiring patterns (wiring electrodes) on a substrate 12 are formed wider than other patterns and no insulation film is formed on the parts, the parts act like a light reflection section reflecting a light component that is spread leterally from light emitting elements 13 and does not directly emit a light to an original. Thus, the light emitted from the light emitting elements to the original includes the light component that is spread laterally from light emitting element 13, does not directly emit the light to the original and is reflected in the light reflection section in addition to the direct light from the light emitting elements. Furthermore, since areas around both ends of the substrate in a reading direction in the area of the light reflection section are designed wider than an area in the middle of the substrate, shading is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus such as a handy scanner or a contact image sensor (CIS) for reading characters, images and other various data, and more particularly to a light receiving section such as a CCD without increasing the number of light emitting parts. The present invention relates to an image reading apparatus capable of accurately reading various information and a light emitting array therefor.

[0002]

2. Description of the Related Art A handy scanner, which is a kind of image reading apparatus, has a housing in contact with a document on which characters, images and other various information are printed. A window in which a transparent plate is fitted is formed on the bottom of the housing. Inside the housing, a light emitting unit that irradiates the original through the transparent plate, a light receiving unit such as a CCD that receives the reflected light from the original, and further converges the reflected light reflected by the reading width of the original A lens and the like for forming an image on the light receiving unit are built in.

[0003] Such a handy scanner is disclosed in USP
No. 4,703,186.

In the light emitting section of the image reading device, a light emitting array such as an LED or a semiconductor laser is generally used for downsizing. The main part of the conventional light emitting array will be described with reference to FIGS.

The light emitting array shown in FIGS. 12 and 13 is a transparent plate 1 made of glass or the like facing a document 10 (see FIG. 13).
And a substrate 2 disposed in parallel with the transparent plate 1 at a predetermined interval. Substrate 2 has a large number of chip LEDs
Light emitting elements 3 such as are arranged at predetermined intervals in one direction by the length of the reading width of the document 10. Here, the whole of the plurality of light emitting elements 3 is hereinafter referred to as “light source L”.

As shown in FIG. 12, a wiring pattern connecting each light emitting element 3 of the light source L is connected to a common wiring pattern 4 a connected to one electrode of the light emitting element 3 and to another electrode of the light emitting element 3. It is composed of a common wiring pattern 4b and a wiring pattern portion 4c for connecting the light emitting elements. Each wiring pattern is made of copper foil, and a portion other than the light source L is coated with an insulating resist 5 for preventing corrosion of the copper foil.

[0007] In such a light emitting array, light emitted from the light emitting element 3 is, as shown in FIG.
, Which illuminates the original 10 through the light, a light y which spreads laterally from the light emitting element 3, and a light z which is a reflection component reflected by the transparent plate 1. The light x of the transmission component irradiated on the document 10 is reflected on the document 10 and becomes reflected light. The reflected light is converged by a lens of an image reading device (not shown), is incident on a light receiving unit such as a CCD, and forms an image. The light y spreading laterally from the light emitting element 3 and the light z of the reflection component reflected on the transparent plate 1 are absorbed by the resist 5 on the wiring pattern portion 4.

[0008]

In such a configuration, in order to increase the amount of light received by the light receiving section, it is necessary to increase the number of light emitting elements of the light emitting array.

A document 1 shown in FIG.
A lens for converging and imaging the reflected light from 0 has a property that an image at the end of the lens field is darker than an image at the center of the lens. As a result, shading occurs. That is,
The intensity of the light received at both ends of the light receiving unit is smaller than the light received at the center of the light receiving unit, and light cannot be received with uniform illuminance.

Further, in the case of the handy scanner, since various components are housed in the housing, the mounting position of the substrate of the light emitting array is restricted. In particular, in order to reduce the size, the optical path length from the light emitting element 3 to the document 10 in FIG. As the optical path length becomes shorter, the characteristics of the lens that converges the light reflected from the document on the light receiving section further deteriorate, and the transmittance around the lens further decreases. For this reason, the light amount at the end of the light receiving section such as a CCD decreases, and the information on the document 10 cannot be read accurately.

On the other hand, Japanese Patent Application Laid-Open No. 63-115285 discloses an image reading apparatus in which when light reflected from a document is focused on a light receiving portion by a lens, the light is received by the light receiving portion with uniform illuminance. Have been. The light-emitting array used in this image reading device is configured such that a large number of light-emitting elements are arranged (the arrangement pitch of the light-emitting elements is reduced) from the center of the illuminated range to the end (corresponding to the end of the document). The intensity of light emitted from the end is increased.

However, the cost increases as the number of light emitting elements increases. Conversely, when the number of light-emitting elements is reduced, the distance between the light-emitting elements is widened, so that not only does the light amount as a light source decrease overall, but also the light amount difference (ripple) as a light distribution.
Becomes large.

Therefore, by making the resist 5 white in the light emitting array shown in FIG. 12, the light y spreading laterally from the light emitting element 3 and the light z of the reflected component reflected on the transparent plate 1 as shown in FIG. A technique has been proposed in which the light is reflected toward the original to increase the reflection efficiency.

However, at present, sufficient reflection cannot be obtained even when a white resist is used. Conventionally, a white resist is formed on the entire surface other than the light source of the light emitting element. Therefore, the problem of shading caused by the characteristics of the lens is reduced as described in JP-A-63-115285. Had to increase.

It is an object of the present invention to provide a light emitting array and an image reading device capable of irradiating a light receiving section with light of sufficient intensity without increasing the number of light emitting elements.

It is another object of the present invention to provide a light emitting array and an image reading apparatus capable of eliminating the influence of shading and uniformly irradiating a light receiving section with light having a sufficient intensity.

[0017]

According to the image reading apparatus of the present invention, the light emitted from the light emitting element can be fully utilized by utilizing the light spreading laterally from the light emitting element or the light reflected by the transparent plate. The illumination intensity can be easily obtained without increasing the number of light emitting elements, and a light receiving unit such as a CCD can accurately read information on an object to be read.

The light emitting array of the image reading apparatus according to the present invention is formed on a substrate, a plurality of light emitting elements mounted on the substrate and irradiating light to an object to be read, and connected to each light emitting element to be formed on the substrate. And a wiring pattern.

The wiring pattern portion is characterized in that the wiring width is wider than the other patterns, and that the wiring pattern portion has a light reflecting portion which extends laterally from the light emitting element and reflects light of a component which does not directly irradiate the original.

In the present invention, an insulating layer is formed on portions other than the light reflecting portion and the light emitting portion of the light emitting element.

An image reading apparatus according to the present invention includes a substrate, a plurality of light emitting elements mounted on the substrate and irradiating light to an object to be read, and a wiring pattern connected to each light emitting element and formed on the substrate. Having a light-receiving array, a light-receiving device, and an optical system that converges reflected light from the object to be read and forms an image on a war-light receiving device, and the wiring pattern portion has a wiring width wider than other patterns, and A light reflecting portion that extends laterally from the light emitting element and reflects light of a component that does not directly irradiate the document.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the image reading apparatus of the present invention, and FIG. 2 is a side view of FIG. In the figure, an image reading apparatus includes a light emitting array 10 that irradiates light parallel to the reading width of a document 40, a CCD 20 that receives reflected light from the document 40 and generates an image signal,
And a lens 30 for converging the reflected light reflected at the reading position and forming an image on the CCD.

Light from the light emitting array 10 illuminates the reading position of the document 40. At this time, reflected light corresponding to the image pattern at the reading position of the document 40 enters the lens 30. The lens 30 converges the reflected light including the image pattern, and
2 is imaged. Thus, the CCD 20 generates an image signal according to the image pattern.

FIG. 3 is a plan view showing details of the light emitting array 10 (first embodiment), and FIG. 4 is a sectional view taken along the line AA of FIG. The light-emitting array 10 includes a substrate 12 arranged in parallel with the document reading direction, wiring patterns 14a, 14b and 14c formed on the substrate 12, and a plurality of LEDs 13 arranged at predetermined intervals on the substrate. Have.

The LEDs 13 are arranged in one direction by the length of the reading width of the document 40. The interval between each LED 13 is LED
Although it depends on the directivity and the luminous intensity, 5 to 10 mm is appropriate. However, it is not limited to this. LED1
The shape and configuration of 3 are not particularly limited.

As shown in FIG. 3, the wiring patterns on the substrate include a common wiring pattern 14a connected to one electrode of the LED 13, a wide common wiring pattern 14b connected to the other electrode of the LED 13, It is composed of a wiring pattern 14c connecting between them. The common wiring patterns 14a and 14b are formed long in the reading direction,
Among the one wiring pattern, the common wiring pattern 14b is formed with the largest width.

Each wiring pattern is made of copper foil. An insulating resist 15 for preventing corrosion of the copper foil of the common wiring pattern 14a and the wiring pattern 14c is applied to portions other than the light source L and the common wiring pattern 14b.

FIG. 5 is a circuit diagram showing an electric circuit of the plurality of LEDs 13 on the substrate and the respective wiring patterns 14a, 14b and 14c. As shown in FIG. 7, four LEDs 1
3 as a group, a plurality of LEDs are connected between the common wiring patterns 14a and 14b, and a drive signal is supplied between the common wiring patterns 14a and 14b to form all the LEDs.
13 emits light.

As shown in FIG. 3, the wide common wiring pattern 14b includes an electrode portion 14b-1 extending in the direction in which the LEDs 13 are arranged and a rectangular electrode portion 14b-2 formed on a plane between the LEDs 13. Resist 1 as much as possible
5 is formed in a comb shape so as to reduce the area.

Since the resist 15 is not formed on the surface of the common wiring pattern 14b,
“b” constitutes the light reflecting portion A where the metal surface is exposed. Also,
The light reflecting portion A may be formed by applying solder on the exposed wiring pattern 14b. Since the solder has higher light reflectivity than the copper foil, it is possible to enhance the entire light reflectivity and to prevent corrosion of the copper foil.

In this case, the material itself of each wiring pattern may be entirely made of solder. Further, silver or gold may be used in addition to copper foil and solder.

In order to prevent the exposed metal surface from being corroded or short-circuited, the light reflecting portion A is provided with a transparent protective film (not shown) which does not deteriorate the light reflectivity. ) May be coated.

In such a light emitting array, an LED
As shown in FIG. 6 (a cross-sectional view taken along the line BB in FIG. 3), light emitted from
There is light y of a component which spreads laterally from D13 and does not directly irradiate the document 40. The light x irradiates the document 10. LED1
The light y spread from 3 irradiates the light reflecting portion A which is the common wiring pattern portion 14b. Since the light reflecting portion A is not coated with the insulating resist 5 and the metal surface is exposed, the light y is reflected again, and the reflected light z is reflected on the original 4
Irradiate 0.

Accordingly, the document 40 is irradiated with both the light x of the component directly radiated from the LED 13 and the light y reflected by the light reflecting portion A. The light x, y illuminating the original 40 is reflected, and the amount of light incident on the CCD 20 of FIG. 3 becomes stronger than before, so that the original 40 can be read accurately.

FIG. 7 is a sectional view showing a second embodiment of the light emitting array 10 shown in FIG. 7, the light emitting array 10 is formed by forming a transparent body 16 such as glass on the original surface side of the light emitting array 10 shown in FIG.

Next, the operation of the light emitting array 10 of FIG. 7 will be described. As shown in FIG. 8, light emitted from the LED 13 includes light x of a transmission component transmitted through the transparent body and light LED 1.
There is light y, which is a component that spreads horizontally from 3 and does not directly irradiate the document 40, and light z, which is a reflection component reflected from the transparent body 15.

The light x of the transmission component irradiates the original 40. The light y of the component spread horizontally and the light z of the reflection component from the transparent body 16 irradiate the light reflection part A which is the common wiring pattern part 14b. The light reflecting portion A is not coated with the insulating resist 15 and the metal surface is exposed.
Is reflected again, and the reflected light y and z are
And irradiates the original 40 with the light. As a result, the amount of light incident on a light receiving unit such as a CCD becomes stronger than before, so that the original 40 can be read accurately.

FIG. 9 is a plan view showing a third embodiment of the light emitting array 10 according to the present invention. As shown in FIG. 9, the common wiring patterns 14a and 14b are arranged on both ends of the substrate 12. The wiring pattern 14c connecting the LEDs is formed sufficiently wider than the width of the common wiring patterns 14a and 14b, and the common wiring pattern 14c and the LED are connected to each other.
The area of the resist 15 formed on the surface of the substrate other than 13 is reduced. The wiring patterns 14c between the LEDs have the same shape.

The electric circuit of the light emitting array 10 of FIG. 9 is the same as that of FIG.

The LED 13 and the common wiring patterns 14a, 1
Electrodes 141 and 142 each having a shape similar to that of the wiring pattern 14c are formed at a connection portion with the wiring pattern 4b.
However, the electrodes 141 and 142 are not connected to each other on the substrate.

Since the resist 15 (shaded portion in FIG. 9) is exposed on the wiring pattern 14c connecting the LEDs and the electrodes 141 and 142 without being formed, they constitute the light reflecting portion A. .

According to the third embodiment, the application area of the resist 15 is smaller than that of the first embodiment shown in FIG. 3, and the area of the light reflecting portion A is wider than that of the first embodiment. Therefore, light reflectivity can be further improved.

The light emitting array 10 according to the first to third embodiments uniformly increases the amount of light incident on the CCD, which is a light receiving unit, but has a large area of the light reflecting unit A. May be different depending on the position of the LED 13.

Thus, it is possible to adjust the amount of light applied to the original 40 shown in FIG. 1 so as to have a predetermined distribution. In particular, when the lens 30 is used as shown in FIG. 1, the amount of light from the LEDs at both ends of the substrate 12 of the light emitting array 10 becomes low, so that it is necessary to secure the amount of light at both ends.

FIG. 10 shows LEs at both ends of the substrate of the light emitting array.
It is a top view showing an embodiment (fourth embodiment) for increasing the amount of light from D.

In FIG. 10, a light emitting array 100 is a modification of the first embodiment shown in FIG. The shapes of the common wiring patterns 14a and 14b and the wiring pattern 14c are the same as those of the first embodiment shown in FIG. However, the area of the rectangular electrode portion 14b-2 gradually increases toward the both end directions P of the substrate 12 of the common wiring pattern 14b.

As a result, the amount of light from the light reflectors A located at both ends in the length direction is larger than the amount of light reflected from the light reflectors A located at the center in the longitudinal direction of the substrate 12. Become. Thus, shading caused by the characteristics of the lens 30 in FIG. 1 can be corrected. That is, the illumination intensity around the lens 30 where the transmittance is reduced increases, and the original can be accurately read by the light incident on the light receiving unit.

FIG. 11 shows an original 40 corresponding to the position shown in FIG.
FIG. 5 is a diagram showing a light amount distribution of light irradiated to the light source.

In the light emitting array 100 shown in FIG. 10, the resist 15 applied to the common wiring pattern 14b is larger at the center than at both ends of the substrate 12, and the amount of the resist 15 applied gradually toward both ends is reduced. It is intended to be reduced. Instead of applying the resist 15, more and more solder may be applied so that the area of the common wiring pattern 14 b increases from the center to both ends of the substrate 12.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made within the technical scope described in the claims. For example, the LEDs are not limited to those connected in one row, but may be implemented in the same manner even if they are arranged in two rows.

The light emitting element is not limited to the LED 13, but may be another light emitting body.

Further, in the image reading apparatus, the light emitting array 10 and the CCD 20 are separately arranged as shown in FIGS. 1 and 2, but the light emitting array and the light receiving section are arranged like a contact image sensor. The lens and the lens may be integrated in the housing.

[0054]

According to the present invention, the metal wiring pattern (wiring electrode) serves as a light reflecting portion which extends laterally from the light emitting element and reflects light of a component which does not directly irradiate the original. Therefore, the light emitted from the light emitting element to the document includes, in addition to the direct light x from the light emitting element, light y that spreads laterally from the light emitting element and is reflected by the light reflecting portion without directly irradiating the document, and The light y is efficiently reflected by the light reflecting portion of the wiring pattern made of metal.

As a result, a sufficient amount of light can be applied to the reading section of the document.

Further, even when a transparent body is provided on the surface of the light emitting array on the original side, light reflected from the transparent body can be efficiently reflected by the light reflector, so that the amount of light to the original can be increased.

Further, in the fourth embodiment of the present invention, the area of the light reflecting portion, which is the wiring pattern, is gradually increased toward both ends in the longitudinal direction of the substrate. As a result, the amount of light from the light reflectors located at both ends in the longitudinal direction is larger than the amount of light reflected from the light reflectors located at the center in the longitudinal direction of the substrate.

Therefore, even in a small-sized image reading apparatus in which the optical path length from the light emitting element to the object to be read must be shortened, information (characters, graphics, etc.) on the object to be read can be obtained without increasing the number of light emitting elements. Etc.) can be read accurately.

Further, the image reading apparatus of the present invention does not need to increase the number of light emitting elements, so that the size and cost of the apparatus can be reduced.

Further, since the light reflecting portion can be formed simultaneously with the wiring pattern, the number of manufacturing steps does not increase.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an image reading apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a plan view showing a light emitting array according to a first embodiment of the present invention.

FIG. 4 is a sectional view taken along the line AA of FIG.

FIG. 5 is a circuit diagram showing an electric circuit of the light emitting array of FIG. 3;

FIG. 6 is a sectional view taken along the line BB of FIG. 3, illustrating the trajectory of light.

FIG. 7 is a plan view showing a light emitting array according to a second embodiment of the present invention.

FIG. 8 is a diagram for explaining a trajectory of light in the light emitting array of FIG. 7;

FIG. 9 is a plan view illustrating a light emitting array according to a third embodiment of the present invention.

FIG. 10 is a plan view illustrating a light emitting array according to a fourth embodiment of the present invention.

11 is a diagram showing a relationship between a position on the substrate of the light emitting array of FIG. 10 and a light amount.

FIG. 12 is a plan view showing a light emitting array of a conventional image reading device.

FIG. 13 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 Reference Signs List 10 light emitting array 12 substrate 13 LED 14a, 14b common wiring pattern 14b wiring pattern 15 resist

Claims (9)

[Claims] 1. A substrate, a plurality of light emitting elements mounted on the substrate and irradiating light to an object to be read, and a wiring pattern connected to each of the light emitting elements and formed on the substrate. A light-emitting array, wherein the wiring pattern portion includes a light reflecting portion having a wiring width wider than other patterns and extending laterally from the light-emitting element to reflect light of a component that does not directly irradiate a document. 2. The light emitting array according to claim 1, wherein an insulating layer is formed on a portion other than the light reflecting portion and the light emitting portion of the light emitting element. 3. The light emitting array according to claim 1, wherein the light reflecting portion is coated with a light reflecting film. 4. The light emitting array according to claim 1, wherein the light reflecting portion is coated with solder. 5. The area of the light reflecting portion is wider in a region near both ends in the reading direction of the substrate than in a region of a central portion of the substrate. The light-emitting array according to one item. 6. The wiring pattern includes two common wiring patterns connected to supply driving power for each group of the light emitting elements, and an inter-element wiring pattern connecting the light emitting elements in each group. The light emitting array according to any one of claims 1 to 5, wherein the light reflecting portion is formed on at least one of the two common wiring patterns. 7. The wiring pattern includes two common wiring patterns connected to supply driving power for each group of the light emitting elements, and an inter-element wiring pattern connecting the light emitting elements in each group. The light emitting array according to claim 1, wherein the light reflecting portion is formed on the inter-element wiring pattern. 8. The light emitting array according to claim 6, wherein the light reflecting portion is arranged over a space between the light emitting elements on the substrate. 9. A light-emitting array having a substrate, a plurality of light-emitting elements mounted on the substrate and irradiating light to an object to be read, and a wiring pattern connected to each of the light-emitting elements and formed on the substrate. A light-receiving device, and an optical system that converges reflected light from the object to be read and forms an image on a battle light-receiving device, wherein the wiring pattern portion has a wiring width wider than other patterns, and An image reading apparatus, comprising: a light reflecting portion that spreads horizontally and reflects light of a component that does not directly irradiate a document.