JP3997124B2 - Illumination device for image reading apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a document illumination device of an image reading apparatus in a copying machine, a facsimile, a scanner, or the like.
[0002]
[Prior art]
An image reading apparatus in a copying machine, a facsimile, a scanner, or the like has a document illumination device for illuminating a document to be read. The light source of the document illuminating device needs to be a long light source having a predetermined length because illumination of the document width (main scanning direction) is performed. Conventionally, halogen lamps, fluorescent lamps, Xe lamps, and the like have been used as light sources for document illumination devices.
[0003]
By the way, in recent years, environmental measures are also required for various OA devices, and lower power consumption is also required for image reading apparatuses.
[0004]
[Problems to be solved by the invention]
However, the above-mentioned lamps that have been conventionally used as light sources for document illuminators are all based on the principle of filament light emission and discharge light emission. Therefore, there is a limit to the light emission efficiency. There is a need for a light source.
[0005]
An object of the present invention is to solve the above-described problems in a conventional document illumination device and to provide a document illumination device including a light source with lower power consumption.
[0006]
[Means for Solving the Problems]
According to the present invention, there is provided an illumination device that is mounted on a traveling body of a document scanning type image reading apparatus and irradiates light on an object to be read. arranged, each of the upper surface of the ultraviolet emitting LED elements, longitudinal and chromatic and the longitudinal radius of curvature is the short hand curved both in the lateral direction perpendicular thereto of the lighting device covers the top of elements A covering surface as a first convex lens facing the reading target that is larger than the radius of curvature in the direction, and between the reading target and the LED element above the covering surface as the first convex lens, the lighting of an image reading apparatus phosphor as the second convex lens facing the reading target is focused on the target surface reading light is characterized in that a transparent plate coated from the ultraviolet light-emitting LED devices It is solved by location.
[0007]
Moreover, in order to solve the said subject, this invention proposes arrange | positioning the said several ultraviolet light emitting LED element in zigzag form.
In order to solve the above problems, the present invention proposes that the ultraviolet light emitting LED element is arranged so that the ultraviolet irradiation area on the transparent plate overlaps the ultraviolet irradiation area of the adjacent LED element. To do.
[0009]
Moreover, in order to solve the said subject, this invention proposes that the said ultraviolet light emitting LED element is mounted in a metallic substrate.
[0010]
Moreover, in order to solve the said subject, this invention proposes sealing at least the said ultraviolet light emitting LED element, the board | substrate with which this LED element is mounted, and the said transparent plate integrally with a sealing member.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a main configuration of a general document reading apparatus. In the document reading apparatus 100 shown in this figure, a contact glass 101 is disposed on the upper surface of the apparatus. In the apparatus below the contact glass 101, first and second traveling bodies 104 and 105, a lens 108, a solid-state image sensor (CCD) 109, and the like are disposed.
[0012]
The first traveling body 104 supports the illumination means 102 and the mirror 103, and the second traveling body 105 supports the two mirrors 106 and 107. The first and second traveling bodies 104 and 105 are provided below the contact glass 101 so as to be movable in the left-right direction in the figure, and the second traveling body 105 is at a speed half that of the first traveling body 104. It is supposed to move. The document image on the contact glass 101 is scanned while the traveling bodies 104 and 105 move. When the document is scanned, the reflected light of the document illuminated by the illumination unit 102 is reflected by the mirrors 103, 106 and 107, enters the CCD 109 through the lens 108, and is converted into an electrical signal. The read document image data is appropriately processed as a digital signal, sent to a remote place by a facsimile function, or printed by an image forming apparatus such as a copying machine or a printer. Note that this data can be taken into a computer, image processed, and used as appropriate.
[0013]
In FIG. 1, the illumination means 102 is shown in a lamp-shaped round cross section. However, in the present invention, an ultraviolet light emitting LED and a phosphor as described below are combined as a light source for document illumination. A light source is used.
[0014]
FIG. 2 is a side view showing a configuration of a light source combining an ultraviolet light emitting LED and a phosphor used in the document illumination device according to the present invention. In this figure, a transparent plate (glass or the like) 12 coated with a phosphor 13 is disposed above the LED chip 11. For example, the LED chip 11 using an indium gallium nitride material can emit ultraviolet light. When the ultraviolet light UV emitted from the LED 11 strikes the phosphor 13, the phosphor emits visible light. The emission color of the phosphor 13 can be made freely to some extent by blending several types of phosphors.
[0015]
FIG. 3 is a perspective view showing one embodiment of the document illumination device according to the present invention. The thing of Fig.3 (a) arranges several LED11 in 1 row, and the thing of FIG.3 (b) arranges several LED11 in 2 rows.
[0016]
As shown in this figure, LEDs 11 are arranged in one or two rows on an array substrate 14 such as a glass epoxy substrate, and an energization pattern is formed on the array substrate 14. Above these (upper side in the figure), a transparent plate 12 coated with a phosphor is disposed. As explained in FIG. 2, when the ultraviolet rays (UV) emitted from the arranged LEDs 11 hit the transparent plate 12 (phosphor thereof), the transparent plate 12 emits visible light (VR), and is long in the LED array direction. A long light source (linear light source) 10A or 10B having a thickness is obtained. In addition, illustration of the transparent plate 12 is abbreviate | omitted in FIG.3 (b). Here, an example in which the LEDs 11 are arranged in one or two rows has been introduced. However, the LEDs 11 may be arranged in a plurality of rows of three or more.
[0017]
A light source combining an ultraviolet light emitting LED and a phosphor is superior in luminous efficiency as compared with a conventional lamp light source, and can reduce the power consumption of the document illumination device. As described with reference to FIG. 3, since the fluorescent material 13 applied to the rectangular transparent plate 12 receives the ultraviolet light of the ultraviolet light emitting LEDs arranged in a row and emits visible light, linear illumination necessary for document illumination is obtained. Light (long light source) can be obtained.
[0018]
FIG. 4 is a perspective view showing a second embodiment of the document illumination device. In this figure, a plurality of LEDs 11 are arranged in a staggered pattern. The light source 20A shown in FIG. 4A has two rows of LEDs 11 arranged in a staggered manner, and the light source 20B in FIG. 4B has three rows of LEDs 11 arranged in a staggered manner. Four or more rows of LEDs can also be arranged in a staggered manner. 4A is considered to be a staggered arrangement of one row, two rows of staggered arrangement (in other words, four rows of LEDs 11 arranged in a staggered manner) or three or more rows It can also be a staggered arrangement.
[0019]
Now, as shown in FIG. 4, by arranging a plurality of LEDs 11 in a staggered manner, the LEDs can be arranged more densely than in the embodiment of FIG. For this reason, it is possible to prevent unevenness in visible light emission due to a small amount of light between LEDs (ultraviolet light amount), and to obtain a large amount of visible light (VR).
[0020]
FIG. 5 is a perspective view showing a third embodiment of the document illumination device. The light source 30 shown in this figure is one in which the LEDs 11 are arranged so that the ultraviolet irradiation areas by the LEDs overlap.
[0021]
That is, as shown in FIG. 5, the ultraviolet rays (UV) emitted from the adjacent LEDs 11 are arranged so that the irradiated areas overlap each other as indicated by a dotted circle on the lower surface (lower surface in the drawing) of the transparent plate 12. It has become. For this reason, there is no reduction in the amount of light between the LEDs, unevenness in visible light emission can be prevented, and a large amount of visible light (VR) can be obtained. In addition, a large amount of visible light (VR) can be obtained with a small number of columns. In addition, although the example which arranged LED11 in 1 row was introduced in this figure, it is also possible to arrange LED11 in two or more rows so that the ultraviolet irradiation area | region by LED may overlap. Moreover, it is also possible to arrange those LEDs 11 in a staggered arrangement.
[0022]
FIG. 6 is a perspective view showing a fourth embodiment of the document illumination device. 6A is a front view of the light source 40, and FIG. 6B is a side view.
As shown in FIG. 6, in the LED 41 of the light source 40, the curvature radius of the convex curved lens (covering surface) covering the upper surface of the element is long (the main scanning direction of the image reading apparatus) and short (the sub scanning direction). The curvature radius R2 in the longitudinal direction is different from the curvature radius R1 in the short direction. Thereby, the ultraviolet rays irradiated from the LED 41 become an irradiation region that gently spreads in the long side direction of the lens, and are configured to be condensed in the short side direction of the lens than in the long side direction. For this reason, in the column direction (main scanning direction), it is easy to obtain an overlapping portion of irradiation regions with adjacent LEDs, and it is easy to prevent a decrease in the amount of light between the LEDs even if the distance (longitudinal direction) between the LEDs is separated. Thereby, it is possible to easily obtain a linear light source with no unevenness and a large amount of light. Note that reference numeral G in the figure is a document.
[0023]
The LEDs 41 shown in FIG. 6 can be arranged in a plurality of rows, or can be arranged in a staggered manner.
[0024]
FIG. 7 is a side view showing a fifth embodiment of the document illumination device.
As shown in this figure, in the light source 50 of this example, a transparent plate 52 formed in a lens shape as a transparent plate (with a phosphor not shown) irradiated with ultraviolet rays (UV) from the LEDs 11 is used. Is used. The visible light (VR) emitted by receiving the ultraviolet rays (UV) from the LEDs 11 is condensed on the document surface (the lower surface of the document G) by the lens-shaped transparent plate 52. Although only one LED 11 is shown in the figure, a plurality of LEDs 11 are arranged in a line in the document width direction (main scanning direction). Further, the LEDs 11 can be arranged in a plurality of rows or arranged in a staggered manner. Furthermore, LED41 of FIG. 6 can also be used as LED.
[0025]
In this embodiment, since the visible light (VR) is condensed on the original surface by the lens-shaped transparent plate 52, an efficient linear light source can be obtained. 6 and 7, the substrate 14 (see FIG. 3) on which the LEDs 41 or 11 are arranged is not shown.
[0026]
FIG. 8 is a perspective view showing a sixth embodiment of the document illumination device.
The light source 60 shown in this figure has a plurality of LEDs 11 arranged in a row on a substrate 14 and is integrally sealed with a transparent sealing member 61. In this example, the sealing member 61 is also used as a transparent plate, and the phosphor is applied to the inner surface of the sealing member 61. As the sealing member 61, a material such as synthetic resin or glass can be used. Further, the sealing member 61 can be configured to have a lens action by a material such as synthetic resin or glass.
[0027]
Besides using the sealing member 61 as a transparent plate, a transparent plate to which the phosphor is applied is provided as a separate member, and at least the LED 11, the substrate 14, and the transparent plate of the separate member are sealed by the sealing member. Also good. Further, the sealing member may be a transparent member as a whole, but at least a region where visible light is irradiated onto the document may be transparent. For example, the sealing member is not made of a single member. For example, the sealing member is divided into an end surface on both sides in the longitudinal direction, an end surface on both sides in the lateral direction, and an upper surface = an area where visible light is irradiated on the document. A member can be joined and it can comprise as a sealing member.
[0028]
In addition, although what showed LED11 arranged in a row in the figure is shown, LED11 can also be arranged in multiple rows | lines or it can arrange | position in zigzag form. Furthermore, LED41 of FIG. 6 can also be used as LED.
[0029]
In the present embodiment, each component such as the LED 11 (or LED 41) and the array substrate 14 can be sealed by the sealing member, so that the contamination of each component can be prevented. Further, it is advantageous in terms of strength as compared with the case where each component exists as a single item. Furthermore, handling and assembly work of the image reading apparatus are facilitated.
[0030]
In each of the above embodiments, a metal substrate can be used as the array substrate 14 on which the ultraviolet light emitting LEDs (11, 41) are mounted. In that case, the heat generated by the LEDs (11, 41) is efficiently transmitted to the substrate 14 and the heat dissipation efficiency is increased. If the heat generation of the LED is not efficiently diffused, the light emission amount and life of the LED are reduced, and the light emission amount of the LED also has temperature dependence, so the stability of the visible light amount finally obtained becomes worse. . However, by using a metal substrate as the LED mounting substrate, the heat dissipation efficiency is improved, the light emission amount and lifetime of the LED are prevented from being lowered, the temperature-dependent LED light emission amount is stabilized, and the final visible light amount is also stabilized. .
[0031]
As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. The ultraviolet light emitting diode (LED) and the fluorescent material are not limited to those illustrated, and appropriate materials can be used. The wavelength of ultraviolet rays is not particularly limited. The fluorescent material is not limited to one type, and may be a mixture of two or more types. The number of LEDs arranged in a row, the number of rows, the arrangement, etc. are also arbitrary.
[0032]
【The invention's effect】
As described above, according to the illuminating device of the present invention, a plurality of ultraviolet light emitting LED elements are arranged in a row toward a reading target, and a transparent plate is coated with a phosphor between the reading target and the LED elements. Therefore, the light source combining the ultraviolet light emitting LED and the phosphor is superior in luminous efficiency as compared with the conventional lamp light source, and the power consumption of the document illuminating apparatus can be reduced. Further, it is possible to obtain linear illumination light necessary for document illumination. Furthermore, since the ultraviolet light emitting LED element has a convex lens-shaped covering surface in which the radius of curvature in the longitudinal direction of the illumination device is larger than the radius of curvature in the short direction perpendicular to the longitudinal direction, the longitudinal direction (main scanning direction) Then, it becomes easy to obtain the overlap part of the irradiation area | region with adjacent LED, and even if the space | interval (longitudinal direction) of LED is separated, it is easy to prevent the light quantity fall between LEDs. Thereby, it is possible to easily obtain a linear light source with no unevenness and a large amount of light.
[0033]
According to the configuration of the second aspect, since the plurality of ultraviolet light emitting LED elements are arranged in a staggered manner, the LEDs can be arranged densely, and a reduction in the amount of light between the LEDs can be prevented. For this reason, it is possible to prevent unevenness in visible light emission due to a small amount of light between LEDs (ultraviolet light amount), and to obtain a large amount of visible light (VR).
[0034]
According to the configuration of the third aspect, the ultraviolet light emitting LED element is arranged so that the ultraviolet irradiation area on the transparent plate overlaps the ultraviolet irradiation area of the adjacent LED element. And a large amount of visible light (VR) can be obtained. In addition, a large amount of visible light (VR) can be obtained with a small number of columns.
[0036]
According to the structure of claim 5, since the ultraviolet light emitting LED element is mounted on the metallic substrate, the heat radiation efficiency is improved, the light emission amount and life of the LED are prevented from being lowered, and the light emission amount of the temperature-dependent LED is stabilized. The final visible light quantity is also stable.
[0037]
With the configuration of claim 5 , since at least the ultraviolet light emitting LED element, the substrate on which the LED element is mounted, and the transparent plate are integrally sealed with the sealing member, each component can be sealed with the sealing member. , Each component can be prevented from being soiled. Further, it is advantageous in terms of strength as compared with the case where each component exists as a single item. Furthermore, handling and assembly work of the image reading apparatus are facilitated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main configuration of a document reading apparatus.
FIG. 2 is a side view showing a configuration of a light source in which an ultraviolet light emitting LED and a phosphor are combined.
FIG. 3 is a perspective view showing an embodiment of a document illumination device.
FIG. 4 is a perspective view showing a second embodiment of the document illumination device.
FIG. 5 is a perspective view showing a third embodiment of the document illumination device.
FIG. 6 is a perspective view showing a fourth embodiment of the document illumination device.
FIG. 7 is a side view showing a fifth embodiment of the document illumination device.
FIG. 8 is a perspective view showing a sixth embodiment of the document illumination device.
[Explanation of symbols]
11, 41 LED
12 Transparent plate 13 Phosphor 14 Array substrate 10, 20, 30, 40, 50, 60 Long light source (illumination means)
52 Lens-like transparent plate 61 Sealing member 100 Document reading device UV UV VR Visible light

Claims (5)

In an illuminating device that is mounted on a traveling body of a document scanning type image reading apparatus and irradiates light on a reading object,
A plurality of ultraviolet light emitting LED elements are arranged in a row toward the reading target,
Wherein the upper surface of the ultraviolet light-emitting LED elements, longitudinal and latitudinal have a curved shape, both in the direction said longitudinal radius of curvature is the short side direction of curvature radius perpendicular thereto of the lighting device covers the top of elements Providing a covering surface as a first convex lens facing the reading object that is larger than
As a second convex lens facing the reading target for condensing the light from each ultraviolet light emitting LED element on the reading target surface between the reading target and the LED element above the covering surface as the first convex lens An illuminating device for an image reading apparatus, wherein a transparent plate coated with the phosphor is arranged .   The lighting device according to claim 1, wherein the plurality of ultraviolet light emitting LED elements are arranged in a staggered manner.   The illumination device according to claim 1, wherein the ultraviolet light emitting LED element is disposed so that an ultraviolet irradiation region on the transparent plate overlaps an ultraviolet irradiation region of the adjacent LED element.   The illuminating device according to claim 1, wherein the ultraviolet light emitting LED element is mounted on a metallic substrate. The illumination according to any one of claims 1 to 4 , wherein at least the ultraviolet light emitting LED element, a substrate on which the LED element is mounted, and the transparent plate are integrally sealed with a sealing member. apparatus.

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