CN100407752C - Light source of image reading apparatus and driving device of light source - Google Patents
Light source of image reading apparatus and driving device of light source Download PDFInfo
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- CN100407752C CN100407752C CN2005100833302A CN200510083330A CN100407752C CN 100407752 C CN100407752 C CN 100407752C CN 2005100833302 A CN2005100833302 A CN 2005100833302A CN 200510083330 A CN200510083330 A CN 200510083330A CN 100407752 C CN100407752 C CN 100407752C
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Abstract
The object of the invention is to extend the life of the light source while uniformizing the illuminance intensity in the main scanning direction. The invention is based on a light source of image reading apparatus comprised of film layers laminated on a transparent substrate in the order of a transparent electrode, an area light emitter and a metal electrode, and emitting light by impressing a specific voltage on these two electrodes. And an area light emitter column configured by arranging area light emitters corresponding to each color of R (red), G (green) and B (blue) in the sub scanning direction, or a monochrome area light emitter is arranged repeatedly in the main scanning direction. Accordingly, even when somewhere in the light emitting element has a defect like the film thickness is thin, the current gathering at this point with the low resistance value becomes a very small volume. Therefore, it would not occur that the film burns out from here.
Description
The application is that application number is the dividing an application for the application of " light source of image read-out and the drive unit of light source " that " 02127758.3 ", the applying date be on August 8th, 2002, denomination of invention.
Technical field
The present invention relates to the light source of image read-out.
Background technology
Photocopier or scanner and then have both printer or the multi-function printer of function such as facsimile machine all has the image read-out that reads in image represented on the standardized writing paper with squares or lines optically.
As above-mentioned image read-out, dwindling optical mode (dwindling the CCD mode) is that people know, dwindle in the optical mode at this, by strengthening the depth of focus of lens, has the advantage that under the state that standardized writing paper with squares or lines hikes up from the original copy face, also can access distinct image even can make it, but the shortcoming that also has on the contrary, device maximization and so on.Therefore, when considering the miniaturization slimming of device, usually as shown in Figure 22, use by waiting doubly upright mode will import the driving fit mode of transducer 108 from the information of standardized writing paper with squares or lines.
That is, left and right symmetrically and 2 led array 112 of gradient configuration above original copy face 106, configuration rod-like lens array 121 on the middle upper part position of these 2 led array 112 to stipulate.According to this rod-like lens array 121, can accept to shine the light of above-mentioned original copy face 106.
Here, above-mentioned led array 112 is to arrange a plurality of LED elements 125 to form at substrate 124 as shown in Figure 23.In addition, above-mentioned rod-like lens array 121 arranges rod lens 122 adjacency of the cylindrical shape of defined amount as shown in Figure 24, forms the formation of clamping with substrate 124.
If use such driving fit mode, that then can do device integral body quite owing to can reduce the distance of original copy face 106 and rod lens 122 be little.
This shows, carry out the miniaturization of device, light source is connect closely as much as possible to be configured in the original copy face also be very important.But, because the set that above-mentioned existing led array 112 is point-source of lights, if do not keep the distance to a certain degree of this light source and original copy face can not guarantee the homogeneity of illumination.That is, the miniaturization that use above-mentioned existing led array to carry out device is limited.
Thereby the present patent application people proposes the following electroluminescent membrane that will illustrate is used as the face illuminating source in special permission 2000-217561 patent etc.
That is, as shown in Figure 25,, on the transparency carrier 101 of long glass or transparent resin etc., form ELD 103, form electroluminescent membrane 100 in the above, and then the lamination metal electrode 102 in the above as optical medium at main scanning direction.
In addition, when realizing such face illuminating source with color mode, make at needs on the basis of illumination homogeneous of main scanning direction, as shown in Figure 26, form the versicolor wide electroluminescent membrane 100r100g100b of corresponding R (red) G (green) B (orchid) at sub scanning direction.
As shown in Figure 27, keep predetermined distance 2 face illuminating sources 5 of left and right symmetrically configuration above original copy 9 mutually.Thus, can make shine original copy 9 light via the lens 14 of the middle upper part position that is configured in 2 face illuminating sources 5 orientation sensor 1.
Like this, even make face illuminating source 5, read the illumination that position Pa also can obtain homogeneous at this near reading position Pa.That is, the face illuminating source that replaces above-mentioned existing led array to adopt the present patent application people to be proposed can carry out the miniaturization of device.
But, adopting on the above-mentioned electroluminescent membrane 100r100g100b face illuminating source, there is short problem of life-span.That is, as shown in Figure 26,, then will compile electric current, and electroluminescent membrane 100b is burnt in the position thus at 1 low X place of this resistance value if there are defectives such as thickness is thin in 1 X position somewhere.
Summary of the invention
The present invention is based on above-mentioned existing situation and the invention that proposes, and purpose is to make the long lifetime of seeking the light source of image read-out in the illumination homogeneous of main scanning direction.
The present invention reaches above-mentioned purpose to have adopted following method.
Promptly, the present invention is a kind of light source of image read-out, it forms rete according to the order of transparency electrode, planar luminous body, metal electrode on transparency carrier, and it is luminous by the voltage that 2 above-mentioned electrodes is applied regulation, it is characterized in that: described light source has a plurality of planar luminous bodies, a kind of color in corresponding these the three kinds of colors of red, green, blue of wherein said planar luminous body, described planar luminous body is formed the parallelogram of non-rectangle and on main scanning direction described planar luminous body is carried out repeated arrangement.
Like this, if adopt the formation that light-emitting zone is divided into a plurality of planar luminous bodies, when then even there are defectives such as thickness is thin in the position more somewhere, only be a little owing to concentrate on the electric current of low any of this resistance value, so can not produce the situation of burning film from here.
Description of drawings
Shown in Figure 1 is the formation that is applicable to colour plane illuminating source of the present invention;
Shown in Figure 2 is the formation of the face illuminating source of use in the experiment;
Fig. 3 is the graph of a relation of life-span and aperture opening ratio;
Fig. 4 has been to use the key diagram of the colour plane illuminating source of electroluminescent membrane;
Fig. 5 is the pie graph that is applicable to colour plane illuminating source of the present invention;
Fig. 6 is the key diagram of phase place Z1, phase place Z2 and phase place Z3;
Shown in Figure 7 is the Illumination Distribution of the sub scanning direction of phase place Z1, phase place Z2 and phase place Z3;
Fig. 8 is the key diagram of phase place Z4 and phase place Z5;
Shown in Figure 9 is the Illumination Distribution of the sub scanning direction of phase place Z4 and phase place Z5;
Figure 10 is the key diagram that illumination is disperseed;
Shown in Figure 11 is the formation that is applicable to colour plane illuminating source of the present invention;
Shown in Figure 12 is that the planar luminous body of adjacent color of the same race is similar in the overlapping form of sub scanning direction;
Shown in Figure 13 is that the planar luminous body of adjacent color of the same race is similar in the overlapping form of sub scanning direction;
Figure 14 is the figure that is used to illustrate parabolic Illumination Distribution;
Figure 15 is the figure that is used to illustrate the Illumination Distribution of trapezoidal shape;
Figure 16 is the figure that is used to illustrate edge lengths;
Figure 17 is used to illustrate the figure that utilizes 2 resulting Illumination Distribution of face illuminating source;
Figure 18 is the configuration instruction figure of face illuminating source;
Figure 19 is the measurement result of original copy paper illumination and mtf value;
Shown in Figure 20 is the formation of driven light-emitting element;
Shown in Figure 21 is the formation of driven light-emitting element;
Figure 22 is the pie graph of existing image read-out;
Figure 23 is the oblique view of the light source that possesses of existing image read-out;
Figure 24 is the oblique view of the rod-like lens array that possesses of existing image read-out;
Figure 25 has been to use the oblique view of the black and white face illuminating source of electroluminescent membrane;
Figure 26 has been to use the key diagram of the colour plane illuminating source of electroluminescent membrane;
Figure 27 is the pie graph that has adopted the image read-out of face illuminating source.
Embodiment
Below describe example of the present invention with reference to the accompanying drawings in detail.Here, in the following description, there is the planar luminous body that to constitute 1 light-emitting zone to be called the situation of " light-emitting component " sometimes.
(example 1)
The present invention and above-mentioned prior art are same, form rete according to the order of transparency electrode planar luminous body metal electrode on transparency carrier, are prerequisite with the light source that makes it luminous image read-out by the voltage that 2 above-mentioned electrodes are applied regulation.Here, as shown in Figure 27, be to be that prerequisite describes, but the present invention only is defined in this to possess 2 light sources 5.That is, be not only the formation that possesses 2 light sources, only possessing wherein, the formation of a side light source also is the scope of application of the present invention.
Formation of the present invention and above-mentioned prior art difference only are described below.
At first, in the present invention, as shown in Figure 1, in the main scanning direction repeated arrangement arranged the planar luminous body 5r5g5b planar luminous body row G of the versicolor wide equal length of corresponding R (red) G (green) B (orchid) at sub scanning direction.
Like this, if according to the formation of the light-emitting zone of divisional plane luminous element more carefully, even if then there is the situation of defectives such as thickness is thin more somewhere, the electric current that concentrates on low some place of this resistance value also only is a little.Thereby, can not produce the situation of burning film from here, as a result of can seek the long lifetime of the light source of image read-out.
Here, the lead RrRgRb that is shown in this figure is connected with the transparency electrode that planar luminous body 5r5g5b uses respectively, and in addition, lead Rc is connected with metal electrode (public electrode).
But between light-emitting component, it needs to be provided with certain certain interval on forming and handling.Thereby if the light-emitting zone of divisional plane luminous element meticulously, then the shared ratio (hereinafter referred to as " aperture opening ratio ") of light-emitting zone will reduce in the Zone Full of light source.
Therefore, in the present invention, on the basis of the best area of determining light-emitting component, as shown in Figure 2, be that 2.5mm and all light-emitting components that changed length L d have been measured its life-span to width.Its result as shown in Figure 3, along with the broadening of the area of light-emitting component, the life-span shortens with being parabolic shape as can be known, in addition, aperture opening ratio then linearity ground raises.
It is best that length that it is generally acknowledged light-emitting component is made the 3mm degree.Promptly as can be known, if the area of light-emitting component is made 7.5mm
2(degree of 2.5mm * 3mm) then can obtain the above life-span of 8000hr when obtaining 80% aperture opening ratio.
As above, if the area correspondence that makes planar luminous body according to the life-span of light source and the determined area of dependency relation of aperture opening ratio, then can be sought the long lifetime of the light source of image read-out when obtaining the aperture opening ratio that satisfies.
Here, though the area of light-emitting component is being made 7.5mm
2Obtained thinking best result during degree, but this area is not to be the special area that limits.That is, the dependency relation of the life-span of light source and aperture opening ratio exists with ... the thickness of light-emitting component, the treatment conditions that film generates, all conditions such as cleannes of device.Thereby, also can change even if be considered to the area of best light-emitting component with the variation of these all conditions.
In addition, illustrated here is black and white face illuminating source, but the present invention only is defined in this black and white light source.That is, on the point of the area correspondence that makes planar luminous body according to the determined area of dependency relation of life-span of light source and aperture opening ratio, the colour plane illuminating source also is the same.
(example 2)
As above-mentioned, in example 1, in the main scanning direction repeated arrangement arranged the planar luminous body row G of the planar luminous body 5r5g5b of the versicolor wide equal length of corresponding RGB at sub scanning direction.Adopt such way, then can when obtaining the aperture opening ratio that satisfies, seek the long lifetime of the light source of image read-out.
But, utilize such face illuminating source, though the Illumination Distribution of main scanning direction has reached homogeneous, the Illumination Distribution of sub scanning direction can not reach homogeneous.That is, at sub scanning direction, because the versicolor planar luminous body 5r5g5b of corresponding RGB is for reappearing at interval in accordance with regulations, so the versicolor Illumination Distribution of the RGB of sub scanning direction is the waveform that is spaced apart 1 cycle with this.
In order to solve above-mentioned problem, as shown in Figure 4, can be at the versicolor wide planar luminous body 100r100g100b of the corresponding RGB of main scanning direction repeated arrangement.Adopt such way, must present one at sub scanning direction because of the versicolor planar luminous body 100r100g100b of corresponding RGB, so can make the versicolor Illumination Distribution of the RGB of sub scanning direction reach homogeneous.
If but adopted such face illuminating source, though the Illumination Distribution of sub scanning direction has reached homogeneous, the Illumination Distribution of main scanning direction could not reach homogeneous.That is, at main scanning direction, because the versicolor planar luminous body 100r100g100b of corresponding RGB reproduction at interval in accordance with regulations, so the versicolor Illumination Distribution of the RGB of main scanning direction is the waveform that is spaced apart 1 cycle with this.
The difference of this example and above-mentioned example 1 only is described below.
At first, in this example, shown in Fig. 5 (a) like that, arranged the capable G1 of a plurality of planar luminous bodies at sub scanning direction, so that make the phase place of mutual main scanning direction have only the difference of a kind of color intensity of planar luminous body.The capable G1 of this so-called planar luminous body has referred in the main scanning direction repeated arrangement delegation of the planar luminous body 5r5g5b of the versicolor wide equal length of corresponding RGB.
Adopt such way, owing to all be bound to occur the versicolor planar luminous body 5r5g5b of corresponding RGB in which phase place of main scanning direction, so can make the versicolor Illumination Distribution homogeneous of the RGB of main scanning direction.In addition owing to which phase place at sub scanning direction all is bound to occur the versicolor planar luminous body 5r5g5b of corresponding RGB, so also can make the versicolor Illumination Distribution homogeneous of the RGB of sub scanning direction.
Perhaps, also can be shown in Fig. 5 (b) like that, arrange the capable G1 of a plurality of planar luminous bodies at sub scanning direction, so that the phase place of mutual main scanning direction has only the difference of planar luminous body semispecies color intensity.But, if adopt such formation, compare with the formation that has adopted the light source shown in Fig. 5 (a), on the face of the Illumination Distribution homogeneous that makes the versicolor main scanning direction of RGB, effect more or less diminishes, and reads nearby such advantage of position but there is the illumination peak of sub scanning direction to appear at.
That is, when the face illuminating source 5 that has adopted shown in Fig. 5 (a), the illumination peak of sub scanning direction does not appear at and reads near the position.For this point is described in more detail, as shown in Figure 6, provided phase place (phase place Z1, phase place Z2 and phase place Z3) about different mutually main scanning directions, the Illumination Distribution of its sub scanning direction is shown in Fig. 7.
At first, owing to have planar luminous body 5r1, so can obtain the Illumination Distribution Y1 that light produced that sends by this planar luminous body 5r1 at the sub scanning direction of phase place Z1.The illumination peak of this Illumination Distribution Y1 (that is the illumination peak of the sub scanning direction of phase place Z1) appears at the left that reads position Pa on this drawing.
In addition, owing to have planar luminous body 5r2, so can obtain the Illumination Distribution Y2 that light produced that sends by this planar luminous body 5r2 at the sub scanning direction of phase place Z2.The illumination peak of this Illumination Distribution Y2 (that is the illumination peak of the sub scanning direction of phase place Z2) is consistent with reading position Pa on this drawing.
And then, owing to have planar luminous body 5r3, so can obtain the Illumination Distribution Y3 that light produced that sends by this planar luminous body 5r3 at the sub scanning direction of phase place Z3.The illumination peak of this Illumination Distribution Y3 (that is the illumination peak of the sub scanning direction of phase place Z3) appears on this drawing and reads the right-hand of position Pa.
Corresponding, when the face illuminating source 5 that has adopted shown in Fig. 5 (b), the illumination peak of sub scanning direction will appear at and read near the position.For this point is described in more detail, as shown in Figure 8, provided phase place (phase place Z4 and phase place Z5) about different mutually main scanning directions, the Illumination Distribution of its sub scanning direction is shown in Fig. 9.
At first, owing to have planar luminous body 5r1 and 5r2, so can obtain the Illumination Distribution Y1 that light produced and the Y2 that send by this planar luminous body 5r1 and 5r2 at the sub scanning direction of phase place Z4.The illumination peak of this Illumination Distribution Y1 appears at the left that reads position Pa on this drawing, the illumination peak of this Illumination Distribution Y2 is then consistent with reading position Pa on this drawing.
Thereby the illumination peak (that is the illumination peak of the sub scanning direction of phase place Z4) that has synthesized the Illumination Distribution of this Illumination Distribution Y1 and Y2 reads position Pa and appears at the side of keeping left slightly.
In addition, owing to have planar luminous body 5r2 and 5r3, so can obtain the Illumination Distribution Y2 that light produced and the Y3 that send by this planar luminous body 5r2 and 5r3 at the sub scanning direction of phase place Z5.The illumination peak of this Illumination Distribution Y3 appears on this drawing and reads the right-hand of position Pa, and the illumination peak of this Illumination Distribution Y2 is then consistent with reading position Pa on this drawing.
Thereby the illumination peak (that is the illumination peak of the sub scanning direction of phase place Z5) that has synthesized the Illumination Distribution of this Illumination Distribution Y2 and Y3 reads position Pa and appears at the side of keeping right slightly.
When the face illuminating source 5 that has adopted shown in Fig. 5 (b), the illumination peak of sub scanning direction appears at and reads position phenomenon nearby, be not only the phase place Z4 and the Z5 of above-mentioned main scanning direction, occur similarly at other each phase place place of main scanning direction.
Thereby, when the face illuminating source 5 that has adopted shown in Fig. 5 (b), shown in Figure 10 (b) like that, the illumination when standardized writing paper with squares or lines does not hike up disperse 61 and the illumination of standardized writing paper with squares or lines when hiking up disperse 62, its characteristic does not almost change.
In contrast, when the face illuminating source 5 that has adopted shown in Fig. 5 (a), shown in Figure 10 (a) like that, the illumination when standardized writing paper with squares or lines does not hike up disperse 61 and the illumination of standardized writing paper with squares or lines when hiking up disperse 62, its characteristic is different fully.
In addition, claim to be used for to make the illumination of the image of transducer 1 output be separated into constant correction and be " dispersing correction " at main scanning direction.That is, read the illumination of blank sheet of paper and specific main scanning direction at first and disperse, after, if consider this illumination dispersion and disperse correcting image, then can obtain the image that does not have illumination to disperse.
As above-mentioned, when the face illuminating source 5 that has adopted shown in Fig. 5 (b), when standardized writing paper with squares or lines hikes up and the illumination of standardized writing paper with squares or lines when the not hiking up characteristic of disperseing almost do not change.Thereby this moment is because initial specific illumination disperses former state effective unchangeably, so can disperse correction.Therefore, when the mode that reads as image adopts platform base mode (aftermentioned), adopt the face illuminating source 5 shown in Fig. 5 (b) comparatively suitable, can disperse correction effectively like this.
In contrast, when the face illuminating source 5 that has adopted shown in Fig. 5 (a), the characteristic that the illumination when not hiking up with standardized writing paper with squares or lines when standardized writing paper with squares or lines hikes up is disperseed is different fully.Thereby, because initial specific at this moment illumination dispersion is invalid, so can not disperse correction.Therefore, when the mode that reads as image adopts plane feeding mode (aftermentioned), adopt the face illuminating source 5 shown in Fig. 5 (a) comparatively suitable, can make the Illumination Distribution homogeneous of main scanning direction like this.
Like this, read mode, preferably selectively adopt the some of the face illuminating source 5 shown in the face illuminating source 5 shown in Fig. 5 (a) and Fig. 5 (b) according to image.But, also can adopt the face illuminating source 5 shown in Fig. 5 (b) when adopting the plane feeding mode, also it doesn't matter to adopt the face illuminating source 5 shown in Fig. 5 (a) when adopting the platform base mode.
Here, above-mentioned so-called plane feeding mode refers to and makes standardized writing paper with squares or lines move to imaging sensing head side by cylinder to read the mode that is depicted in the image on its standardized writing paper with squares or lines.When this mode of employing, do not need to consider whether hiking up of standardized writing paper with squares or lines.
The opposing party, above-mentioned so-called platform base mode refers to standardized writing paper with squares or lines is fixed on the glass platform, by its down mobile imaging sensing head read the mode that is depicted in the image on its standardized writing paper with squares or lines.Adopt this method, have the advantage that to use the such standardized writing paper with squares or lines that thickness is arranged of books or magazine, but must consider hiking up of standardized writing paper with squares or lines.
(example 3)
The difference of this example and above-mentioned example 2 only is described below.
That is, in this example, as shown in Figure 11, form parallelogram and in the main scanning direction repeated arrangement planar luminous body 5r5g5b of the versicolor wide equal length of corresponding RGB.
Even utilize such formation, as shown in Figure 12, if adjacent as can be known homochromy planar luminous body (is red planar luminous body 5r at this) in the overlapping placement of sub scanning direction, can realize also that then illumination is dispersed in 10%.
Especially, as shown in Figure 13, at summit, the bottom right C of the planar luminous body of the adjacent color of the same race of the left upper apex A0 of certain planar luminous body with this planar luminous body
1When being positioned at the right side, can realize that as can be known illumination is dispersed in 5%.
As above, by adopt forming parallelogram and, can obtain the effect roughly the same with above-mentioned example 2 in the formation of the planar luminous body 5r5g5b of the versicolor wide equal length of the corresponding RGB of main scanning direction repeated arrangement.
(example 4)
But, realize purpose depth of focus D, can access distinct image even then need standardized writing paper with squares or lines to hike up also.And, can access distinct image even want standardized writing paper with squares or lines to hike up also, then need as will be described below like this, make the Illumination Distribution of sub scanning direction become trapezoidal shape.
Promptly, as the parabolic Illumination Distribution Y_2 that (the drawing upper and lower is to the direction that hikes up for standardized writing paper with squares or lines) obtains when standardized writing paper with squares or lines hikes up that Figure 14 provides, the parabolic Illumination Distribution Y_1 that (standardized writing paper with squares or lines is attached to the situation on the glass platform) obtains when standardized writing paper with squares or lines does not hike up.As shown in the drawing, when the Illumination Distribution of sub scanning direction becomes parabolic shape,, then can not obtain distinct image because of the illumination step-down that reads position Pa if standardized writing paper with squares or lines hikes up.
Here, for convenience of explanation, be explanation, but we can say that about utilizing 2 face illuminating sources, 5 resulting Illumination Distribution also be the same utilizing a face illuminating source 5 resulting Illumination Distribution to carry out.That is in possessing the formation that 2 face illuminating sources 5 are arranged, as shown in Figure 17, only be the synthetic face illuminating source 5 resulting Illumination Distribution of utilizing separately.
Corresponding, shown in Figure 15 is the Illumination Distribution Q_2 of the trapezoidal shape that obtains when standardized writing paper with squares or lines hikes up, the Illumination Distribution Q_1 of the trapezoidal shape that (, standardized writing paper with squares or lines is attached to the situation on the glass platform) obtains when standardized writing paper with squares or lines does not hike up.As shown in the drawing, when the Illumination Distribution of sub scanning direction becomes trapezoidal shape, even standardized writing paper with squares or lines hikes up, but because of the illumination that reads position Pa does not have step-down, so also can access distinct image.
The Illumination Distribution of sub scanning direction be made trapezoidal shape, simple way is the width that enlarges the light-emitting component of sub scanning direction.But if enlarge the width of light-emitting component, then not only cost rises, and also will cause the maximization of device.
Thereby in this example, we have adopted following gimmick.
Shown in Figure 16 is the Illumination Distribution Q_1 of the Illumination Distribution Q_2 of the trapezoidal shape that obtains when standardized writing paper with squares or lines hikes up and the trapezoidal shape that obtains when standardized writing paper with squares or lines does not hike up.
Here, the last edge lengths W of the Illumination Distribution of the trapezoidal shape of sub scanning direction utilizes more than the value that following formula tries to achieve.Here, the given what is called " θ " of this formula is meant the center O and the line segment and the original copy face angulation that read position Pa of link surface illuminating source 5.
[formula 1]
W＝2D/tanθ
If the right-angled triangle F that provides with thick line among attention Figure 16 then can easily derive this formula.That is because the length on the base of this right-angled triangle F is W/2, highly be D,, so tan θ=D/ (W/2) promptly tries to achieve formula 1.
Like this, if go up edge lengths W greater than 2D/tan θ, when then standardized writing paper with squares or lines hikes up and the illumination that reads position of standardized writing paper with squares or lines when not hiking up equate.Therefore, the width of expansion light-emitting component can make top length W reach more than the 2D/tan θ.But, as illustrating, all inconvenience is arranged because enlarge the width of light-emitting component, so in the present invention, the decision optimization should go up edge lengths W.
That is, though detailed content will be narrated in the back, best above-mentioned angle θ is 40 ° to 55 ° the scope of being limited to.Thereby the width of light-emitting component is determined on the condition ground of having stipulated in the present invention to make edge lengths W satisfy following formula.Adopt such way, can Min. ground suppress all inconvenience of producing because of the width that enlarges light-emitting component, can access distinct image even standardized writing paper with squares or lines hikes up also.
[formula 2]
2D/tan55°＜＝W＜＝2D/tan40°
Here, for edge lengths W on the optimization, determine the width of change light-emitting component, but the present invention only is defined in this.For example, also can and read variable in distance between the position because go up edge lengths W, so also can come edge lengths W on the optimization by changing this distance according to the center of light source.
Here, common photocopier approximately needs the depth of focus of 2mm.When making the present invention be applicable to such photocopier, as can be known above-mentioned angle θ is being set at 40 °, simultaneously,, approximately need the last edge lengths W of 4mm with the center of light source with when reading distance setting between the position and being 3mm.In addition, also, approximately need the wide light-emitting component of 3mm as can be known in order to realize edge lengths W on this.
Provide below above-mentioned angle θ is limited to 40 ° of foundations to 55 ° of scopes.
At this, make the position of face illuminating source and angle produce many variations, and measured, estimated standardized writing paper with squares or lines illumination and MTF (modulation transfer function, the Modulation TransferFunction) value of this moment.Here, so-called mtf value also is referred to as the resolution of transducer.
At first, the black and white face illuminating source that connects 2 length 160mm width 4mm in long hand direction (main scanning direction) constitutes the A3 size, as shown in Figure 18, the light source 5 of these 2 A3 sizes is installed respectively in the both sides of lens 14.And, in the center O of fixedly connected illuminating source 5 and the length r that reads the line segment L between the Pa of position is under the state of 5mm, make this line segment L and original copy paper 9 angulation θ change to 70 ° from 20 ° always, and measured standardized writing paper with squares or lines illumination and the mtf value of this moment.
By its result as can be known, obtained the above original copy paper illumination of 1600lx be shown in Figure 19 (a) like that, angle θ is the situation more than 30 °, obtained the mtf value more than 75% be shown in Figure 19 (b) like that, angle θ is the situation below 60 °.That is, we can say that angle θ is scope preferably from 30 ° to 60 °.
In addition, also as can be known, obtained the above original copy paper illumination of 2000lx be shown in Figure 19 (a) like that, angle θ is the situation more than 40 °, obtained the mtf value more than 80% be shown in Figure 19 (b) like that, angle θ is the situation below 55 °.That is, we can say that angle θ is good especially scope from 40 ° to 55 °.
More than exactly above-mentioned angle θ is limited to 40 ° of foundations to 55 ° of scopes.
Here, illustrative is black and white face illuminating source, but we have also obtained same result when having used the colour plane illuminating source.In addition, though be here in the face illuminating source that uses the 4mm width, fixedly the length r of line segment L is 5mm, but as can be known by the situation of under other condition, having carried out measuring, angle θ also is a scope preferably from 30 ° to 60 ° situation, and angle θ also is good especially scope from 40 ° to 55 ° situation.
(example 5)
In addition, as shown in Figure 20, for driven light-emitting element, simple way is exactly the constant-current source M driven light-emitting element of utilizing one by one respectively, if but adopt such formation then cost will rise.That is,, then preferably adopt and utilize a constant-current source to drive the formation of a plurality of light-emitting components if consider from the cost aspect.
But, utilize a constant-current source to drive the formation of a plurality of light-emitting components if merely adopt, then will impair the effect of the long lifetime and so on of light source.Even if this is because a bit there are defectives such as thickness is thin in the somewhere of certain light-emitting component, but because other the electric current of light-emitting component of should flowing through is pooled to some place on this light-emitting component, so will burn film from here.
Therefore, in the present invention, for the rising that do not cause cost and reach without detriment to the such effect of the long lifetime of light source, we determine to utilize following formation to come driven light-emitting element.
That is, shown in Figure 21 (a) like that, electrically connect a plurality of light-emitting components and 1 constant-current source M via impedance body N.Though the resistance value of this impedance body N does not limit especially, should select to be far longer than the bigger value of the resistance value of light-emitting component L.
If adopt such way, even if a bit there is the situation of defectives such as thickness is thin in the somewhere of certain light-emitting component, because to the almost not influence of summation of the resistance value of impedance body and light-emitting component, so other the electric current of light-emitting component of should flowing through can not be pooled to a bit locating on this light-emitting component.
Perhaps shown in Figure 21 (b) like that, also can connect a plurality of impedance body N and light-emitting component L, and connect the constant pressure source O that apply the voltage of regulation at two ends separately.Utilize such formation,, then also can obtain effect same as described above if select the resistance value of impedance body N to be far longer than the bigger value of the resistance value of light-emitting component L.
As above, in the present invention, determining that employing does not cause the rising of cost and can reach without detriment to the formation of the long lifetime of light source comes driven light-emitting element.
In addition,, do not limit only to connecting a plurality of light-emitting components and 1 constant pressure source is illustrated at this but the number of the light-emitting component that is connected with a constant-current source is special.That is, both whole light-emitting components can be connected with 1 constant-current source, perhaps also can be connected with a constant-current source on the versicolor light-emitting component of corresponding by group RGB ground, and then, can also each Fig. 1 or connection constant-current source in planar luminous body row G ground shown in Figure 5.Certainly, we can say that the number for the light-emitting component that is connected with a constant-current source also is same situation.
In addition, in the above description, illustrative is the light source of image read-out, but the present invention also goes for the light source of the such image writer of printhead.That is, so long as on transparency carrier, form rete according to the order of transparency electrode planar luminous body metal electrode, and make it luminous light source by the voltage that 2 above-mentioned electrodes are applied regulation, all can be suitable for the present invention.
As above, according to the present invention, even if there are defectives such as thickness is thin more somewhere, but because of being pooled to the low electric current of a bit locating of this resistance value only a little, so can not produce the problem of burning rete and so on from here, as a result of, can seek the long lifetime of the light source of image read-out.
In addition, in the present invention, since be with in the main scanning direction repeated arrangement phase place of the capable mutual main scanning directions of a plurality of planar luminous bodies of the versicolor planar luminous body of corresponding RGB differently be arranged on the sub scanning direction, so can realize the Illumination Distribution homogeneous of main scanning direction.
And then, according to the present invention, even if because exist more somewhere under the situation of defectives such as thickness is thin, it is to the almost not influence of summation of the resistance value of impedance body and light-emitting component, so other the electric current of light-emitting component of should flowing through can not be pooled to a bit locating on this light-emitting component.That is rising that, can be by not causing cost and can reach without detriment to the formation of the long lifetime of light source and come driven light-emitting element.
Claims (4)
1. the light source of an image read-out, it forms rete according to the order of transparency electrode, planar luminous body, metal electrode on transparency carrier, and luminous by the voltage that 2 above-mentioned electrodes is applied regulation, it is characterized in that:
Described light source has a plurality of planar luminous bodies, a kind of color in corresponding these the three kinds of colors of red, green, blue of each described planar luminous body wherein, described planar luminous body is formed the parallelogram of non-rectangle and on main scanning direction described a plurality of planar luminous bodies is carried out repeated arrangement.
2. the light source of image read-out according to claim 1, it is characterized in that: the planar luminous body of adjacent color of the same race is overlapping on sub scanning direction top.
3. the light source of image read-out according to claim 1 is characterized in that: the area that makes above-mentioned planar luminous body is corresponding to according to the life-span of light source and the determined area of dependency relation of aperture opening ratio.
4. the light source of image read-out according to claim 1, it is characterized in that: getting the goal-focus degree of depth is that D, the center that links light source and the line segment that reads the position and original copy paper angulation are when being θ, determine the width of the above-mentioned planar luminous body of sub scanning direction, so that the last edge lengths of the Illumination Distribution of the trapezoidal shape of sub scanning direction is more than or equal to 2D/tan55 °, and be less than or equal to 2D/tan40 °.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001241664 | 2001-08-09 | ||
| JP241666/2001 | 2001-08-09 | ||
| JP241664/2001 | 2001-08-09 | ||
| JP241665/2001 | 2001-08-09 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021277583A Division CN100423532C (en) | 2001-08-09 | 2002-08-08 | Light for image pickup device and driving device therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1722766A CN1722766A (en) | 2006-01-18 |
| CN100407752C true CN100407752C (en) | 2008-07-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2005100833302A Expired - Fee Related CN100407752C (en) | 2001-08-09 | 2002-08-08 | Light source of image reading apparatus and driving device of light source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100407752C (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05318822A (en) * | 1991-08-23 | 1993-12-03 | Fuji Xerox Co Ltd | Image bar and driving method thereof and electronic type printer |
| JPH0640072A (en) * | 1992-07-24 | 1994-02-15 | Toshiba Corp | Optical printer head |
| JPH11252306A (en) * | 1998-03-03 | 1999-09-17 | Seiko Instruments Inc | Contact type color image sensor |
| CN1273641A (en) * | 1998-06-05 | 2000-11-15 | 精工爱普生股份株式会社 | Light source and display device |
-
2002
- 2002-08-08 CN CN2005100833302A patent/CN100407752C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05318822A (en) * | 1991-08-23 | 1993-12-03 | Fuji Xerox Co Ltd | Image bar and driving method thereof and electronic type printer |
| JPH0640072A (en) * | 1992-07-24 | 1994-02-15 | Toshiba Corp | Optical printer head |
| JPH11252306A (en) * | 1998-03-03 | 1999-09-17 | Seiko Instruments Inc | Contact type color image sensor |
| CN1273641A (en) * | 1998-06-05 | 2000-11-15 | 精工爱普生股份株式会社 | Light source and display device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1722766A (en) | 2006-01-18 |
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