JPH09169134A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source capable of setting illuminance and illuminance distribution in a simple structure. SOLUTION: In a light source body 12 wherein a plurality of point light sources 276 are arranged in a prescribed arrangement patterns, a control means divides the point light sources into regions having identical or different sizes in accordance with an instructed light arrangement distribution. The illuminance of each of the regions is controlled by the ratio of numbers of the point light sources between turn-on and turn-off. The turn-off point light sources are arranged at regular intervals. Only the turn-on or turn-off of each of the point light sources is controlled, so that the control means is simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device composed of a plurality of point light sources.

[0002]

2. Description of the Related Art Conventionally, a light source device has been used in which a plurality of point light sources are arranged to form one light source as a whole. In this light source device, point light sources such as light emitting diodes are arranged in a straight line or in a matrix at equal intervals. When drive power is supplied to the light source device, each light emitting diode uniformly emits light and illuminates the object. Compared with the case where one light source is used, it has a feature that a light source device having a uniform light amount linearly or in a plane can be easily realized. Utilizing this feature, this light source device is used as a light source of a scanner or a printer. The brightness of the light source is changed by changing the current supplied to the point light source or by supplying a pulsed current and changing the duty ratio.

Further, when the present light source device is used as a light source of an LCD (liquid crystal display device), it is sometimes desired to change the brightness distribution of the light source in order to correct shading generated in the LCD. In such a case, a light distribution correction plate is arranged between the light source and the liquid crystal display device to change the brightness distribution.

[0004]

However, in order to change the current supplied to the light source or supply the pulsed current, complicated control is required. Further, when the brightness distribution is changed by the light distribution correction plate, since the light amount distribution of the light source itself varies, it is necessary to adjust the light distribution correction plate for each device, which is complicated. Also, the adjustment accuracy was not high.

In view of the above facts, the present invention has an object to obtain a light source device capable of easily adjusting the brightness and the brightness distribution and performing the adjustment with high accuracy.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 is such that a plurality of point light sources are provided in a predetermined array pattern, and the point light sources are independent of each other. Point light source driving means for turning off and turning on and off, the maximum light amount when all point light sources are turned on, the light source main body is divided when obtaining the instructed light amount, and the divided point light source groups are turned on and turned on. And a control means for setting the ratio of the point light sources to be turned off.

According to the invention described in claim 1, when the brightness of the light source is instructed by the control means, the instructed brightness is converted into the ratio of the light source that is turned on and the light source that is not turned on.
The control means divides the point light source group into regions composed of at least one point light source according to the above ratio, and determines whether to turn off or turn on each point light source in each region. Then, a signal for driving the point light source is sent to the point light source driving means. Each point light source is
Brightness can be adjusted with a simple circuit by controlling only on (lighting) and off (lighting off).

A second aspect of the invention is characterized in that, in the first aspect of the invention, the light source body is divided into light source groups having the same number of point light sources.

According to the second aspect of the present invention, the light source body is divided into a plurality of areas having the same number of point light sources, and each area is indicated by a ratio of a light source that is turned on and a light source that is not turned on. It emits bright light.

According to a third aspect of the present invention, in the first aspect of the present invention, the light source main body is divided into a plurality of types of light source groups having different numbers of point light sources and arranged at predetermined relative positions. It is characterized by that.

According to the third aspect of the present invention, the ratio of the point light sources to be turned on and off is determined based on the brightness distribution by the control means, and the area including the point light sources is determined. For each area, a point light source to be turned off is selected according to the above ratio, and a signal for driving the point light source is sent to the point light source driving means. That is, the light source device can emit light according to the instructed brightness distribution. The ratio of turning on / off the unit point light source in each region is different, and if each region is defined according to the accuracy required to have high adjustment accuracy of the light quantity, the turning on / off control can be simplified.

The invention described in claim 4 is the invention according to claims 1 to 3.
In the invention according to any one of items 1 to 3,
It is characterized by having a light diffusing device disposed between the light source body and the illumination target.

According to the fourth aspect of the invention, when the distance between the point light sources is wide, the lights are not sufficiently mixed with each other, which may cause an undesirable uneven brightness. In such a case, the light diffusing device is arranged on the path of light from the light source body to the irradiation target of the light source body. When the light source emits light and light enters the light diffusing device, the incident light is diffused inside the light diffusing device and emitted. The emitted light becomes light in which the unevenness is eliminated by the light diffusing device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows an image recording apparatus 10 having a light source body 12 according to a first embodiment of the present invention. The image recording apparatus 10 is mainly configured to record a document image at a normal size.

An upper surface of the apparatus is opened, and a moving plate 252 is attached through a pair of rails (not shown) parallel to each other. The moving plate 252 is movable along the rail in the left-right direction on the paper surface of FIG. 1, and is moved by the driving force of a driving unit (not shown).

A rectangular hole 254 is provided in the moving plate 252, and a transparent glass plate 256 is attached. The original 258 is placed on the transparent glass plate 256 with the image facing downward. Also, the transparent glass plate 2
A pressing cover 260 that can be opened and closed corresponding to 56 is attached, and by closing the pressing cover 260 with the original 258 placed on the transparent glass plate 256, the original 258 can be held.

A magazine 264 in which color photographic paper as a photosensitive material 262 is wound into a roll and accommodated therein is loaded in the apparatus, and a pair of rollers 266 and a cutter 268 are provided in the vicinity of the outlet. It is arranged. Therefore, the photosensitive material 262 pulled out from the pull-out port is nipped by a pair of rollers 266, cut into a predetermined length by a cutter 268, and then guided by a guide plate 272 by driving a roller pair 270 to move the moving plate. The sheet is conveyed in the moving direction of 252 (the direction of arrow A in FIG. 1).

The transparent glass plate 256 and the photosensitive material 2
An exposure device 274 is provided in a space between the transportation locus of 62.

The exposure device 274 is provided with a light source body 12 and a rod lens array 278. Light emitted from the light source body 12 is reflected by the original 258, and the reflected light passes through the rod lens array 278 and reaches the surface of the photosensitive material 262. Manuscript 2
The image of 58 is formed at the same size. In the light source body 12, 100 point light sources 276 are linearly arranged as shown in FIG. The point light source 276 includes a predetermined number of red, green, and blue light emitting diodes (hereinafter, referred to as LEDs), and a group of the LEDs is treated as one point light source 276. The light source main body 12 is installed so that the width direction thereof is perpendicular to the moving direction of the document, and the document 258 is moved to scan the document 258 uniformly. Further, since the light source main body 12 and the original 258 are installed with a certain distance, the light source main body 1
The light emitted from the light source 2 is mixed almost evenly on the original 258 to become white light.

Here, by moving the moving plate 252 and the photosensitive material 262 at the same speed in the same direction, the original 2
58 images can be scan exposed (see phantom lines in FIG. 1). After scanning exposure, the moving plate 252 returns to the original position (solid line position in FIG. 1).

The photosensitive material 262 on which the image is formed is sent to the adjacent developing section 280 and is subjected to a developing process.

The light source body 12 is connected to the control unit 14. The control unit 14 controls each point light source 27 of the light source body 12.
Control means for deciding light emission / extinction of No. 6 and point light source driving means for controlling the drive current to the point light source 276 according to the decision of the control means. 100 point light sources 276 are 1
The point light sources 276 can be turned on (lit) and turned off (extinguished) independently of each other. Further, all the LEDs included in one point light source 276 are turned on / off at the same time. In other words, each point light source 276 has only two states of ON (lighting) and OFF (lighting off).

The control means is an all-point light source 27 of the light source body 12.
The brightness when 6 is turned on is 100%, and all point light sources 276
The lighting pattern of the point light source 276 is determined according to the brightness indicated by a numerical value of 0 or more and 100% or less, with the brightness when 0 is turned off as 0%. The regions are divided so that the number of the point light sources 276 in each region is uniform, and each region is set so that the ratio of the number of the point light sources 276 to be turned on to the number of the point light sources 276 to be turned off follows the brightness. . The lighting patterns of the point light sources 276 to be turned off are determined such that the point light sources 276 in the adjacent regions are also spaced from each other at a constant interval.

The operation of the first embodiment will be described below. By placing the original 258 on the transparent glass plate 256 and closing the pressing cover 260, the positioning of the original 258 is completed.

When the start of exposure is instructed, the photosensitive material 262 held by the pair of rollers 266 is pulled out from the magazine 264 and cut by the cutter 268 to a predetermined length.

The control means of the control unit 14 gives an instruction to start the light source selection processing in accordance with the previously designated brightness. First, in order to divide the point light source 276 group of the light source body 12 into regions, the number of point light sources 276 per region is obtained.
The point light source 276 is evenly divided into areas each including the above-mentioned number of point light sources 276. In each area, a predetermined number of point light sources 276 are turned off and the others are turned on. Point light source 276
Are turned off at equal intervals, and since the light source body 12 and the original 258 are installed with a sufficient distance therebetween, the point light source 276 is not turned off so that the brightness does not become uneven.

FIG. 3 shows an example in which the brightness is 80%. The light source body 12 is composed of five point light sources 276.
It is divided into 0 areas, and one point light source 2 in the center of each area
76 is turned off.

With the above processing, the light source selection processing ends, and the light emission pattern of the point light source 276 is determined. afterwards,
A point light source 27 is provided via a point light source driving unit included in the control unit 14.
6 is driven according to the determined light emission pattern, the light source body 12 is caused to emit light with a uniform brightness distribution, and exposure is started.

By moving the moving plate 252 and the photosensitive material 262 in the same direction and at the same speed, the image surface of the original 258 is line-scanned, and the reflected light is reflected by the rod lens array 278 on the photosensitive surface of the photosensitive material 262. Is imaged.

The image-formed photosensitive material 262 is transferred to the developing unit 28.
A copied image can be obtained by sending the image to 0 and developing it.

According to the first embodiment, the light source body 12
Each of the point light sources 276 configuring the above has only two states of ON (lighting) and OFF (lighting off), so that the control circuit can be simplified. Moreover, the brightness of the entire light source can be changed by changing the number of the point light sources 276 to be turned off. By making the intervals of the point light sources 276 to be turned off uniform, it is possible to change the brightness while maintaining a uniform light distribution.

(Second Embodiment) An image recording apparatus 2 provided with a light source body 12 according to a second embodiment with reference to FIG.
0 will be described. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The feature of the second embodiment is that the brightness of the light source body 12 is set as a distribution.

The control means provided in the controller 24 is assigned a small area in the darkly set section and a large area in the brightly set section according to the light distribution distribution stored in advance. Point light source 276 to be turned off for each area
When the numbers of the same are the same, it is possible to irradiate according to the set light distribution. The light distribution can be changed by changing the light source with time or changing the exposure conditions.

As in the first embodiment, the control means determines a predetermined number of point light sources 276 to be turned off for one area. In this embodiment, one point light source 2 is used for one area.
76 is turned off. Since the number of the point light sources 276 to be turned off is constant, the smaller the area (darker), the lower the adjustment accuracy, and the larger (brighter) the area, the higher the adjustment accuracy. The point light sources 276 to be turned off are determined such that the distances between the point light sources 276 in the adjacent regions are equal to each other. In the section to which the small area is allocated, the ratio of the extinguished point light sources 276 becomes relatively large, so that it becomes a dark area, and in the section to which the large area is allocated, the ratio of the point light sources 276 to be lit becomes relatively large and thus bright It becomes an area. In FIG. 5, the light source body 12 is set so that the center thereof is darkened and the light source body 12 is brightened toward both left and right ends.

The operation of the second embodiment will be described below. When the exposure is instructed, the control unit 24 instructs the control means to start the light source selection process. An area is set in the control means based on a preset light distribution. In each area, one central point light source 276 is turned off,
Others are turned on. With the above processing, the light source selection processing of the control means is completed. Each area has one point light source 276 that is turned off. The drive unit drives the point light source 276 according to the determination of the control unit. The light source body 12 emits light with a lightness distribution that changes depending on the density of the point light sources 276 that are turned on. In the example of FIG. 5, the density of the point light source 276 to be turned on is low in the center, increases as it approaches the left and right ends, becomes darker in the center, and becomes brighter as it approaches the ends.

Each point light source 276 needs to be controlled only in two states, that is, off and on, so that the driving unit is simplified and the number of parts is reduced. Also, when changing the distribution, the control unit 2
4 can be easily changed only by changing the settings stored in the control means.

(Third Embodiment) The configuration of a light source device according to the third embodiment will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. For the light source body 12, either a light source having a uniform distribution as in the first embodiment or a light source having a distribution change as in the second embodiment can be used. The feature of the third embodiment resides in that the diffuser 16 which is a light diffusing device is arranged in the optical path from the light source body 12 to the original 258. The diffuser 16 has a function of diffusing incident light and emitting it. It is a sheet of synthetic resin that is mainly roughened and has a thickness of about 0.1 mm. When a light source capable of setting a light distribution is used for the light source body 12, a diffuser that diffuses the brightness of each area to a uniform level is used to maintain the set distribution.

If the light source body 12 has a point light source 276.
If the number of the light sources is sufficiently large, the lights from the adjacent point light sources 276 are sufficiently mixed by the time they reach the original document 258 even if the diffuser 16 is not provided, and the original document 258 is illuminated with uniform white light. However, when the number of the point light sources 276 is not sufficient, the lights from the adjacent point light sources 276 reach the original 258 without being sufficiently mixed, and the light distribution is not uniform, which is not desirable. In the present embodiment, the diffuser diffuses the light irradiating the original 258, and enables a uniform light distribution even when the number of point light sources 276 is not sufficient.

The operation of the third embodiment will be described below.
First, similarly to the first and second embodiments, the photosensitive material 262 is used.
When the front end surface of the sheet reaches a predetermined position, the photosensitive material 2 starts from this point.
The moving plate 252 starts to move in the same direction and at the same speed as the conveyance direction guided by the guide plate 272 of 62, and the point light source 276
Lights up.

The light emitted from the point light source 276 provided in the light source body 12 enters the surface of the diffuser 16.
The incident light diffused by the diffuser 16 is emitted from the opposite surface, becomes uniform light, and illuminates the original 258. Since the unevenness of the brightness of the undesired light source is averaged to make uniform light, a uniform light distribution can be maintained even when the number of light sources is small.

In the first to third embodiments, three colors (red,
A point light source array was used in which point light sources with a predetermined number of green and blue LEDs were arranged in a straight line, but three monochromatic point light source arrays (red point light source array, green point light source array, blue point light source) were used. Array) may be used. Further, it is possible to adjust the color tone by changing the lightness or the light distribution for each color.

Although the reflective original 258 has been described in the first to third embodiments, when the transparent original 282 is used as shown in FIG. 6, the transparent original is placed between the light source body 12 and the rod lens array 278. 282 may pass through.

In the first to third embodiments of the present application, the controller changes the lighting pattern of the point light source while the light source is scanning the original 258, so that the original 258 is moved in the moving direction. The light distribution can be changed.

In the first to third embodiments of the present application, the number of point light sources turned off in each area is constant, and the point light source turned on and turned off by changing the size of the area according to the given brightness. However, the number of point light sources to be turned on may be changed according to the brightness while keeping the area size constant. For example, the brightness is previously set to 0, 10, 30, 50, 7
When it can be predicted that it will be selected from 0, 90, and 100%, the number of point light sources in one area is 10, and when 30% is selected, three light sources are lit, and when 90% is selected. 9 lights. Also, the brightness is 15%, 45%, 9
When selecting from 5%, 20 point light sources in one area
When 15% is selected, three lights are lit, and when 95% is selected, 19 lights are lit. Since the area is fixed, the area division process can be omitted.

Further, in the first to third embodiments, the light source device in which the point light sources are arranged linearly has been described, but the light source device in which the point light sources are arranged in a matrix is also divided into regions to reduce the light amount. Can be set. FIG. 8 shows an example of division into areas of equal size. A uniform light distribution can be obtained by making the number of point light sources turned off in each region uniform.

FIG. 9 shows an example of a matrix light source device which is divided so that the sizes of the regions are different. As shown in FIG. 9A, the light source body is divided into a small area at the center and a large area at the ends. By making the number of point light sources turned off for each area uniform, the small area becomes relatively darker than the large area. FIG. 9C shows a light distribution distribution on the x-axis of the light source body. Since a small area is assigned to the center, the brightness of the center is low. FIG. 9B shows a case where the amount of light at the end is low, such as when an LCD (liquid crystal display) is projected by a lens. In this case, the light distribution on the x-axis of the light source body is uniform, but in the LCD projection image, the light amount on the x-axis is high at the center and low at the edges (FIG. 9 (D)).
reference). In this case, when a light source having the characteristics shown in FIG. 9C is used as the LCD light source, both characteristics are canceled and LC
The D projection image can obtain a uniform light amount distribution as shown in FIG.

[0047]

As described above, the light source device according to the present invention has two ON / OFF (ON) and OFF (OFF) for each point light source.
It has an excellent effect that the brightness of the light source and the distribution of the brightness can be easily changed while simplifying the device by controlling only the above states.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image recording apparatus according to an embodiment of the first invention of the present invention.

FIG. 2 is a front view showing an arrangement of a light source device and a point light source according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an example of area division of a light source in the embodiment of the first aspect of the present invention.

FIG. 4 is a front view showing the arrangement of a light source device and a point light source according to the second embodiment of the present invention.

FIG. 5 is a diagram showing an example of area division of a light source according to the second embodiment of the present invention.

FIG. 6 is a schematic view showing the arrangement of light source devices when a transparent original is used in the image recording apparatus according to the first to third embodiments of the present invention.

FIG. 7 is a schematic view showing the arrangement of diffusers in the image recording apparatus according to the third embodiment of the present invention.

FIG. 8 is a diagram showing an example in which a light source device in which point light sources are arranged in a matrix is divided into uniform regions.

FIG. 9A is an example in which a light source device in which point light sources are arranged in a matrix is divided into regions of different sizes;
Is a schematic view showing the transmittance of the LCD panel, (C) is a graph showing the light distribution on the x-axis of the light source device, and (D) is the x of the LCD panel when a light source with a uniform light distribution is used. A graph showing the amount of transmitted light on the axis, and (E) is a graph showing the distribution of the amount of transmitted light on the x-axis of the LCD when this light source device is used as the light source of the LCD.

[Explanation of symbols]

 10 and 20 image recording device 12 light source main body 14 and 24 control unit 16 diffuser 276 point light source 278 rod lens array

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display H05B 37/02

Claims (4)

[Claims] 1. A light source main body in which a plurality of point light sources are provided in a predetermined array pattern, a point light source driving means for turning off and turning on each point light source independently, and a maximum amount of light when all point light sources are turned on. A light source device comprising: a light amount; and a control unit that divides the light source body when obtaining the instructed light amount and sets a ratio of point light sources to be turned on and off for each of the divided point light source groups. 2. The light source device according to claim 1, wherein the light source body is divided into light source groups having the same number of point light sources. 3. The light source device according to claim 1, wherein the light source body is divided into a plurality of types of light source groups having different numbers of point light sources and arranged at predetermined relative positions. 4. The light source device according to claim 1, wherein the light source device has a light diffusing device arranged between the light source body and the illumination target.