JP7049094B2 - Line light source and optical line sensor unit equipped with this - Google Patents

Description

The present invention relates to a line light source used as an illumination light source of an optical line sensor unit for reading paper sheets such as banknotes and securities, and an optical line sensor unit including the line light source.

As an optical line sensor unit for reading paper sheets, a unit including a long light guide body and a light source provided at the end of the light guide body is used. In this optical licensor unit, an exit surface is formed along a part of the peripheral surface of the light guide body along the longitudinal direction. Further, the light guide body has a light diffusion pattern formed along the longitudinal direction at a position facing the emission surface. In this optical licensor unit, the light emitted from the light source is reflected on the inner surface of the light guide body a plurality of times and then incident on the light diffusion pattern. Then, the light incident on the light diffusion pattern is diffused by the light diffusion pattern, and the diffused light is emitted from the emission surface. In this way, the optical licensor unit emits line-shaped light from the emission surface (see, for example, Patent Document 1 below).

In such an optical licensor unit, the illuminance (intensity distribution) of the light emitted in a line shape may differ depending on the irradiation position. Specifically, among the line-shaped light emitted from the optical licensor unit, the intensity of the light emitted from the exit surface near the light source may be extremely high. This is due to the fact that the light emitted from the light source is directly incident on the light diffusion pattern without being reflected on the inner surface of the light guide, and the diffused light is emitted from the emission surface. Such non-uniform light intensity (uneven illuminance) causes problems in subsequent image processing and the like.

From this point of view, in the optical licensor unit described in Patent Document 1, fine irregularities for dispersing light are formed on the portion of the emission surface of the light guide body in the vicinity of the light source by embossing. In this optical licensor unit, the light emitted from the emission surface near the light source is diffused by the unevenness formed on the light guide body, thereby reducing the intensity of the light emitted from the emission surface near the light source.

Japanese Unexamined Patent Publication No. 2013-145710

However, in the conventional optical licensor unit as described above, all the light emitted from the exit surface near the light source is diffused by the unevenness formed on the light guide body. Therefore, the light is diffused to the originally required light like the light emitted from the exit surface near the light source after being reflected multiple times in the light guide and then diffused by the light diffusion pattern, and the light utilization efficiency is lowered. There was a problem such as.

The present invention has been made in view of the above circumstances, and includes a line light source capable of suppressing non-uniformity of the intensity of light emitted from a light guide and suppressing a decrease in light utilization efficiency. It is an object of the present invention to provide an optical line sensor unit.

The line light source according to the present invention is a line light source used as an illumination light source of an optical line sensor unit for reading paper sheets. The line light source includes a light guide body, at least one light source, a light diffusion pattern, and an angle conversion reflection unit. The light guide has a long shape, and an exit surface is formed along the longitudinal direction. The at least one light source faces at least one end face of the light guide in the longitudinal direction, and causes light to enter the inside of the light guide from the end face. The light diffusion pattern is provided along the longitudinal direction of the light guide body, diffuses the light incident on the inside of the light guide body, and emits the light from the emission surface. The angle conversion reflecting portion is provided on the main light path connecting the end portion on the light source side and the light source in the light diffusion pattern, and the angle of a part of the light incident on the inside of the light guide body from the light source is determined. It has an angle conversion function to convert. For example, if the reflecting surface is a mirror surface, only the reflection angle is converted and most of the light returns to the light source. If it is a diffused surface, a part of the light reaches the light entering portion of the light guide, and the remaining light returns to the light source.

Here, the main optical path refers to the refractive index of the light guide that connects an arbitrary point on the end of the light source side in the main scanning direction of the light diffusion pattern in the vicinity of the light entry portion with any one point of the light source, and In the case of an LED with a lens, it means an optical path that is the center in a region surrounded by a group of light rays having a certain stereoscopic angle, which is determined by the relationship including the refractive index of the lens.
Since the number of the above-mentioned solid angles of a large number of point light sources exists from a light source having a size, it is necessary to shield a certain region, and therefore, it is necessary to block the vicinity of the main optical path.

According to such a configuration, the angle conversion reflection unit is provided in the vicinity of the main optical path connecting the end portion on the light source side and the light source in the light diffusion pattern. Then, a part of the light emitted from the light source and incident on the inside of the light guide body is angle-converted by the angle-converting reflecting unit and reflected or diffused.

Therefore, among the light emitted from the light source, the light directly directed to the end of the light source side in the light diffusion pattern without being reflected by the inner surface of the light guide is angle-converted (including diffusion) or the light source side. By returning to, it is possible to prevent direct incident on the light diffusion pattern.
As a result, the amount of light emitted from the light source and directly incident on the light diffusion pattern can be adjusted or reduced. Then, it is possible to prevent the intensity of the light diffused by the light diffusion pattern from becoming extremely high in the vicinity of the light entering portion.
Therefore, it is possible to suppress the non-uniformity of the intensity in the vicinity of the light input portion of the light emitted from the light guide.

Further, among the light from the light source, only the light that causes the non-uniformity of the intensity of the light emitted from the light guide is diffused or reflected by the angle conversion reflecting unit to adjust or reduce the amount of light. Can be done.

Therefore, the light intensity distribution in the main scanning direction can be made uniform while maintaining the light utilization efficiency.
As described above, according to the line light source according to the present invention, the non-uniformity of the intensity of the light emitted from the light guide can be suppressed, and the decrease in the efficiency of light utilization can be suppressed.

Further, the angle conversion reflecting unit may have a diffuse reflection, a mirror surface reflection, or an angle conversion function by reflection including diffuse reflection and specular reflection.

With such a configuration, it is possible to reliably prevent the light emitted from the light source from directly incident on the light diffusion pattern.

Further, the line light source may further include a mixing space. The mixing space is formed by a reflecting surface that reflects the light angle-converted by the angle-converting reflecting unit, and guides the light reflected by the reflecting surface to the inside of the light guide together with the light from the light source.

According to such a configuration, among the light emitted from the light source, the light diffusely reflected or angle-converted by the angle-converting reflecting unit is reflected by the reflecting surface formed in the mixing space and inside the light guide. Can be incident. Alternatively, the return light to the light source side is reflected again by the reflecting surface, passes through the mixing space, is incident on the angle conversion reflecting portion again, is diffusely reflected or angle-converted, and a part of the light is incident on the light guide portion. Then, the rest becomes the return light. The light incident on the end face of the light guide body without incident on the angle conversion reflecting portion does not incident on the light diffusion pattern in the vicinity of the light input portion, but incidents on a position away from the light diffusion pattern.

That is, among the light emitted from the light source, the light incident on the angle conversion reflection portion returns to the light source side or is incident on the light guide portion. Further, among the light emitted from the light source, the light that is not incident on the angle conversion reflection portion is directly incident on the light input portion of the light guide body.
Further, the return light to the light source side is reflected by the reflecting surface on the light source side and heads toward the light guide body side again. Then, among the light directed to the light guide body side, the light incident on the angle conversion reflection portion returns to the light source side or is incident on the light guide body incoming light portion. Further, among the light directed to the light guide body side, the light that does not enter the angle conversion reflecting portion directly incidents on the light input portion of the light guide body. The reflective surface on the light source side uses a highly reflective material (material) corresponding to each wavelength, or is coated with a highly reflective material to improve the retroreflection efficiency.

In this way, by repeating the diffuse reflection or angle conversion of light in the angle conversion reflecting portion and the reflection of light in the reflecting surface, the amount of light directly incident on the light diffusion pattern in the vicinity of the light input portion can be limited or adjusted. , The light intensity distribution becomes uniform.
Moreover, as described above, it is possible to suppress a decrease in light utilization efficiency due to the effect of utilizing retroactive light.
In other words, by allocating the increase in light intensity in the vicinity of the light input portion to other portions, it is possible to improve the uniformity of the light intensity distribution without lowering the light utilization efficiency.

Further, in the line light source, the mixing space may be formed so as to be arranged so as to face the end face of the light guide body.
According to such a configuration, the mixing space can be formed at an appropriate position.

Further, the line light source may further include a tubular member. The tubular member is arranged so as to face the end surface of the light guide body, and the mixing space is formed inside. The mixing space may be formed so that the cross-sectional area becomes at least equal to or larger than the area of the end portion on the light source side as the distance from the light source increases.

According to such a configuration, the emission intensity of the light reflected by the reflecting surface forming the mixing space approaches parallel, the Fresnel loss at the end surface of the light input portion of the light guide body can be reduced, and the light passing through the mixing space can be efficiently transmitted. It can be incident inside the light guide.
Fresnel loss means that when light is incident on a different medium, the reflectance (transmittance) changes depending on the angle of incidence, and the reflectance increases as the angle of incidence increases, and is expressed by the Fresnel equation. To.
It is preferable that the reflective surface on the inner surface of the mixing space has a mirror surface or a surface property close to the mirror surface.
In a mixing space having an expanding cross-sectional shape such as the trumpet type, the reflection angle is closer to the optical axis of the light guide when reflected on the inner surface thereof, and therefore the incident angle is changed when the light is incident on the end face of the light guide. Since the size is reduced, the transmittance at the interface between the light guide and the air is improved, so that the incident efficiency is increased.

Further, a recess for accommodating the light source may be formed on the end face of the light guide body. The angle conversion reflecting portion may be provided in the recess.
With such a configuration, it is possible to realize a miniaturization of the line light source.

Further, the line light source may further include a light-shielding portion. The light-shielding portion is provided at a position facing the concave portion on the emission surface of the light guide body.

According to such a configuration, the light emitted from the light source is diffusely reflected or angle-converted by the angle conversion reflecting unit, directed toward the light guide body emission surface, and directly to the outside from the emission surface near the light guide body entrance surface. It is possible to suppress the emission.

Further, the light-shielding portion may be an optical filter having an arbitrary transmittance with respect to the wavelength of the light source, or may be made of a combination of an optical filter and a diffusion material.

According to such a configuration, it is possible to take out the light in the vicinity of the light input portion of the light guide body.

Further, at least one arbitrary opening may be formed in the light-shielding portion.

According to such a configuration, it is possible to take out the light in the vicinity of the light input portion of the light guide body.

Further, when the area of the incident region where the light from the light source is incident on the end face of the light guide is D, and the projected area of the angle conversion reflecting portion on the end face of the light guide is S, 8 The relational expression <(D + S) / S <12 may be satisfied.

According to such a configuration, the angle conversion reflecting unit can be configured to have a size suitable for diffuse reflection or angle conversion of light from a light source.

Further, the surface of the angle conversion reflection unit may have a diffuse reflection function composed of a curved surface or a combination of different types of curved surfaces, a specular reflection function, or an angle conversion function by reflection including diffuse reflection and specular reflection.

According to such a configuration, the angle conversion reflecting portion can be provided with an angle conversion function by a simple configuration in which the surface shape of the angle conversion reflecting portion is formed by a curved surface or a combination of different types of curved surfaces.

Further, the surface of the angle conversion reflecting portion may have a diffuse reflection function composed of a plane or a combination of planes having different angles, a mirror reflection function, or an angle conversion function by reflection including diffuse reflection and mirror reflection.

According to such a configuration, the angle conversion reflecting portion can be provided with an angle conversion function by a simple configuration in which the surface shape of the angle conversion reflecting portion is formed by a plane or a combination of planes having different angles.

Further, the surface of the angle conversion reflection unit may have a diffuse reflection function composed of a combination of a flat surface and a curved surface, a mirror surface reflection function, or an angle conversion function by reflection including diffuse reflection and mirror surface reflection.

According to such a configuration, the angle conversion reflecting portion can be provided with the angle conversion function by a simple configuration in which the surface shape of the angle conversion reflecting portion is formed by a combination of a flat surface and a curved surface.

Further, the at least one light source may include a first light source and a second light source. The first light source faces one end face of the light guide in the longitudinal direction, and ultraviolet light is incident on the inside of the light guide from the one end face. The second light source faces the other end face in the longitudinal direction of the light guide, and has a wavelength range including visible light or visible light to infrared light from the other end face to the inside of the light guide. Light is incident.
According to such a configuration, light in the wavelength range including ultraviolet light, visible light, or visible light to infrared light is selected, and the light is emitted from the light source and incident on the inside of the light guide body. be able to.
Therefore, optimum light can be emitted from the emission surface of the light guide.

Further, the line light source may further include a first optical filter. The first optical filter is arranged between one end surface of the light guide and the first light source, transmits ultraviolet light, and has a wavelength range including visible light or visible light to infrared light. Block the light. The angle conversion reflection unit may be provided on the main light path connecting the end portion of the light diffusion pattern on the first light source side and the first light source.

According to such a configuration, only the ultraviolet light emitted from the first light source can be transmitted by the first optical filter and incident on the inside of the light guide body. For example, when the first light source employs a mounting substrate such as an aluminum oxide ceramic sintered body that emits fluorescence when exposed to ultraviolet light, the irradiation light from the first light source hits the mounting substrate and fluoresces. Will be secondarily irradiated. With the above configuration, the fluorescence secondarily irradiated from the first light source can be prevented from entering the inside of the light guide by the first optical filter.

Further, the line light source may further include a second optical filter. The second optical filter is arranged between the other end surface of the light guide and the second light source, transmits visible light, or light in a wavelength range including visible light to infrared light, and is ultraviolet. Block the light. The angle conversion reflection unit may be provided on the main light path connecting the end portion of the light diffusion pattern on the second light source side and the second light source.

According to such a configuration, only the visible light emitted from the second light source or the light in the wavelength range including the visible light to the infrared light is transmitted by the second optical filter and incident on the inside of the light guide body. Can be done. For example, when the second light source employs a mounting substrate that emits fluorescence when exposed to ultraviolet light, such as an aluminum oxide ceramic sintered body, the irradiation light from the first light source passes through the light guide body. Then, it hits the mounting substrate of the second light source and is secondarily irradiated with fluorescence. With the above configuration, the ultraviolet light emitted from the first light source can be prevented from being incident on the second light source by the second optical filter. Then, it is possible to prevent the second light source from being secondarily irradiated with fluorescence.

The optical line sensor unit according to the present invention includes the line light source, a lens array, a light receiving unit, and a third optical filter. The lens array is emitted from the line light source and guides light reflected or transmitted by the paper sheets. The light receiving unit receives the light converged by the lens array and converts it into an electric signal. The third filter is provided between the paper sheets and the light receiving portion, transmits light in a wavelength range including visible light or visible light to infrared light, and ultraviolet light enters the light receiving portion. Block ultraviolet light so that it does not exist.

According to such a configuration, only visible light or light in a wavelength range including visible light to infrared light can be transmitted through the third filter and received by the light receiving unit.
Therefore, it is possible to prevent the secondary irradiation of fluorescence by ultraviolet light in the vicinity of the light receiving portion.

According to the present invention, the angle conversion reflection portion is provided in the vicinity of the main optical path connecting the end portion on the light source side and the light source in the light diffusion pattern. A part of the light emitted from the light source and incident on the inside of the light guide body is angle-converted by the angle-converting reflecting unit and reflected or diffused. As a result of diffuse reflection or angle conversion of the light emitted from the light source and directed to the direct diffusion pattern, the amount of light emitted from the light source and directly incident on the light diffusion pattern can be adjusted or reduced. Therefore, it is possible to suppress the non-uniformity of the intensity in the vicinity of the light input portion of the light emitted from the light guide. Further, among the light from the light source, only the light that causes the non-uniformity of the intensity of the light emitted from the light guide is diffusely reflected or angle-converted by the angle conversion reflecting unit, so that the amount of light is reduced. Can be done. Moreover, since the retroreflective effect is used, it is possible to suppress a decrease in light utilization efficiency.
As described above, by introducing the angle conversion reflection unit, the light emitted from the light source is not directly incident on the light diffusion pattern near the light entry part, so that the intensity of the emitted light near the light entry part is non-uniform. At the same time, it is possible to suppress the deterioration of the light utilization efficiency by reusing the light returned to the light source side (using the retrolight) in the angle conversion reflecting unit.

It is sectional drawing which shows schematic the structure of the optical line sensor unit in embodiment of this invention. It is sectional drawing which shows the additional structure of an optical line sensor unit schematicly. It is a perspective view of a line light source. It is an exploded perspective view which shows each component of a line light source. It is a side view of a line light source. It is a side sectional view of one end of a line light source. It is a front view of one angle conversion reflection part. It is a side sectional view of the other end of a line light source. It is a front view of the other angle conversion reflection part. It is a graph which showed the light intensity distribution with respect to the paper leaf in an optical licensor unit. It is a graph which showed three-dimensionally the intensity distribution of light in a conventional optical licensor unit. It is a graph which showed three-dimensionally the intensity distribution of light in the conventional optical licensor unit different from FIG. 11A. It is a graph which showed three-dimensionally the light intensity distribution in an optical licensor unit when the projected area of an angle conversion reflection part is large. It is a graph which showed the light intensity distribution in the optical licensor unit when the projected area of the angle conversion reflection part is a medium size. It is a graph which showed three-dimensionally the light intensity distribution in an optical licensor unit when the projected area of an angle conversion reflection part is small. It is a graph which showed the utilization efficiency of light in an optical licensor unit. It is a side sectional view of the line light source which concerns on 2nd Embodiment of this invention. It is a side sectional view of the line light source which concerns on 3rd Embodiment of this invention.

<First Embodiment>
<Optical line sensor unit>
FIG. 1 is a schematic cross-sectional view showing the configuration of an optical line sensor unit according to an embodiment of the present invention.
This optical line sensor unit includes a housing 16, a line light source 10 for illuminating paper leaves, and a lens for guiding light emitted from the line light source 10 toward the focal plane 20 and reflected by the paper leaves. The array 11 and a light receiving unit 12 mounted on the substrate 13 and receiving the transmitted light guided by the lens array 11 are provided. Paper leaves are transported in one direction x (secondary scanning direction) along the focal plane 20.

These housing 16, the line light source 10, the light receiving unit 12, and the lens array 11 extend in the y direction (main scanning direction), that is, in the direction perpendicular to the paper surface in FIG. 1, and FIG. 1 shows a cross section thereof. Shows.
The line light source 10 is a unit that emits light toward the paper leaves on the focal plane 20. The types of emitted light are visible light, white light and ultraviolet light, and infrared light may also be emitted.

This ultraviolet light has a peak wavelength in the wavelength range of 300 nm to 400 nm, and the infrared light has a peak wavelength in the wavelength range up to 1500 nm.
Of these lights, at least ultraviolet light is emitted so as not to overlap with other lights in time (that is, while being switched in time). Infrared light may be emitted so as to overlap with visible light in time, or may be emitted so as not to overlap with visible light in time.

The light emitted from the line light source 10 passes through the protective glass 14 and is focused on the focal plane 20. The protective glass 14 is not always necessary and can be omitted, but the line light source 10 and the lens array are prevented from scattering and scratching dust during use (during use) (dust such as paper dust generated during transportation of paper leaves). It is desirable to install it to protect 11.

The material of the protective glass 14 may be any material as long as it transmits light emitted from the line light source 10, and may be a transparent resin such as an acrylic resin or a cycloolefin resin. However, in the embodiment of the present invention, it is preferable to use glass such as white plate glass or borosilicate glass that transmits ultraviolet light.

A substrate 5 for fixing the first light source 3 and the second light source 4 (see FIGS. 4 and 5) installed at both ends of the line light source 10 is installed facing the bottom surface of the line light source 10. The substrate 5 is a thin insulating plate made of phenol, glass epoxy, or the like, and a wiring pattern made of copper foil is formed on the back surface thereof. Terminals (connectors) connected to the substrate 6 on which the first light source 3 is mounted and the substrate 7 on which the second light source 4 is mounted are inserted into holes formed in various parts of the substrate 5 to form the substrate 5. By joining to the wiring pattern with solder or the like on the back surface, the first light source 3 and the second light source 4 can be mounted and fixed on the substrate 5, and wiring from a predetermined drive power source (not shown) to the back surface of the substrate. Power can be supplied to the first light source 3 and the second light source 4 through the pattern to drive and control the light emission thereof.

The lens array 11 is an optical element that forms (converges) the light reflected by paper sheets on the light receiving unit 12, and a rod lens array such as a selfock lens array (registered trademark: manufactured by Nippon Sheet Glass) can be used. can. In the embodiment of the present invention, the magnification of the lens array 11 is set to 1 (upright).

It is preferable to provide an ultraviolet light blocking optical filter 15 at an arbitrary position from the focal plane 20 to the light receiving unit 12 by reflecting or absorbing the ultraviolet light so that the ultraviolet light does not enter the light receiving unit 12. In the embodiment of the present invention, an ultraviolet light blocking optical filter 15 is attached to the surface of the lens array 11 to have a function of blocking ultraviolet light. As used herein, "blocking light" means reflecting or absorbing light and not transmitting it.

The ultraviolet light blocking optical filter 15 is not particularly limited, and may be of any material and structure as long as it can prevent ultraviolet light from entering the light receiving unit 12. For example, an ultraviolet light absorbing film in which an organic ultraviolet light absorber is mixed or coated in a transparent film, or a thin film of a metal oxide or a dielectric having different transmittances and refractive indexes such as titanium oxide and silicon oxide is deposited on the glass surface in multiple layers. The interference filter (band pass filter) obtained by the above is preferable. The ultraviolet light blocking optical filter 15 is an example of a third optical filter.

Although the ultraviolet light blocking optical filter 15 is attached to the exit surface of the lens array 11, it may be attached to the incident surface or the intermediate portion of the lens array 11 and is directly vapor-deposited or applied to the inner surface of the protective glass 14. May be used. In short, it suffices if the ultraviolet light reflected by the paper sheets can be prevented from entering the light receiving unit 12.

The light receiving unit 12 is mounted on a substrate 13 and includes a light receiving element that receives reflected light and reads an image as an electric output by photoelectric conversion. The material and structure of the light receiving element are not particularly specified, and a photodiode or phototransistor using amorphous silicon, crystalline silicon, CdS, CdSe, or the like may be arranged. Further, it may be a CCD (Charge Coupled Device) linear image sensor. Further, as the light receiving unit 12, a so-called multi-chip type linear image sensor in which a plurality of ICs (Integrated Circuits) in which a photodiode, a phototransistor, a drive circuit, and an amplifier circuit are integrated can be arranged can also be used. Further, if necessary, an electric circuit such as a drive circuit or an amplifier circuit, or a connector for taking out a signal to the outside can be mounted on the substrate 13. Further, an A / D converter, various correction circuits, an image processing circuit, a line memory, an I / O control circuit, and the like can be simultaneously mounted on the substrate 13 and taken out as a digital signal.

The above-mentioned optical line sensor unit was a reflection type optical line sensor unit that was emitted from the line light source 10 toward the paper leaves and received the light reflected by the paper leaves. As shown in FIG. A transmissive type in which the line light source 10 is placed at a position opposite to the light receiving unit 12 with the focal plane 20 as a reference, and the light emitted from the line light source 10 toward the paper leaves and transmitted through the paper leaves is received. It may be an optical line sensor unit. In this case, the structure of the line light source 10 itself is not different from that described so far, except that the position of the line light source 10 is below the focal plane 20 only in the arrangement of FIG. Further, both a reflective optical line sensor unit and a transmissive optical line sensor unit may be included.

<Line light source>
FIG. 3 is a perspective view schematically showing the appearance of the line light source 10 in the optical line sensor unit shown in FIG. 1. FIG. 4 is an exploded perspective view of each component of the line light source 10, and FIG. 5 is a side view of the line light source 10. In FIG. 5, the cover member 2 is not shown.

The line light source 10 is provided near the transparent light guide body 1 extending along the longitudinal direction L, the first light source 3 provided near one end face of the longitudinal direction L, and the other end face of the longitudinal direction L. A second light source 4, a cover member 2 for holding each side surface (bottom side surface 1a and left and right side surfaces 1b, 1c) of the light guide body 1, and diagonally formed between the bottom side surface 1a and the right side surface 1b. The light that is formed on the light diffusion pattern forming surface 1g and is incident on the end faces 1f and 1e of the light guide body 1 from the first light source 3 and the second light source 4 and travels through the light guide body 1 is diffused and refracted to guide the light. It has a light diffusion pattern P for emitting light from the light emitting side surface 1d of the body 1.

The light guide body 1 may be formed of a highly light-transmitting resin such as acrylic resin or optical glass, but in the embodiment of the present invention, the first light source 3 that emits ultraviolet light is used, so that the light guide body 1 is guided. As the material of the optical body 1, a fluororesin or a cycloolefin resin having relatively little attenuation to ultraviolet light is preferable.
The light guide body 1 has an elongated columnar shape, and its cross section orthogonal to the longitudinal direction L has substantially the same shape and the same dimensions at any cut end in the longitudinal direction L. Further, the proportion of the light guide body 1, that is, the ratio of the length of the light guide body 1 in the longitudinal direction L to the height H of the cross section orthogonal to the longitudinal direction L (ratio of the length of the longitudinal direction L to the height H). Is greater than 10, preferably greater than 30. For example, if the length of the light guide body 1 is 200 mm, the height H of the cross section orthogonal to the longitudinal direction L is about 5 mm.

The side surfaces of the light guide body 1 are a light diffusion pattern forming surface 1 g (corresponding to an oblique cut surface of the light guide body 1 in FIG. 4), a bottom side surface 1a, left and right side surfaces 1b, 1c, and a light emission side surface 1d (light guide in FIG. 4). It consists of five sides (corresponding to the upper surface of the body 1). The bottom side surface 1a and the left and right side surfaces 1b and 1c have a planar shape, and the light emitting side surface 1d is formed in an outwardly smooth convex curved shape in order to have a light collecting effect of the lens. However, the light emitting side surface 1d does not necessarily have to be formed in a convex shape, and may have a planar shape. In this case, it is preferable to arrange a lens that collects the light emitted from the light guide body 1 so as to face the light emitting side surface 1d.

The light diffusion pattern P on the light diffusion pattern forming surface 1g maintains a constant width and extends linearly along the longitudinal direction L of the light guide body 1. The dimension of the light diffusion pattern P along the longitudinal direction L is formed to be longer than the reading length of the image sensor (that is, the width of the reading region of the light receiving unit 12).
The light diffusion pattern P is composed of a plurality of V-shaped grooves provided on the light diffusion pattern forming surface 1g of the light guide body 1. There are various methods for processing V-shaped grooves, and the general method is to form V-shaped grooves in a mold such as injection molding or pressing, and to form the grooves during molding, but there are other methods as well. There are also methods such as precision engraving. Each of the plurality of V-shaped grooves is formed so as to extend in a direction orthogonal to the longitudinal direction L of the light guide body 1, and has the same length as each other. The cross section of the plurality of V-shaped grooves may be, for example, an isosceles triangle or an asymmetric triangle. Further, the apex corner portion may be rounded.

Due to this light diffusion pattern P, light incident from the end faces 1e and 1f of the light guide body 1 and propagating inside the light guide body 1 in the longitudinal direction L is refracted and diffused, and the light emitting side surface 1d is along the longitudinal direction L. Can be irradiated from.
The V-shape of the groove of the light diffusion pattern P is an example, and can be arbitrarily changed such as a U-shape instead of the V-shape. Further, it may be a dot pattern having various shapes (hemisphere, triangular pyramid, square pyramid, semi-cylinder). The width of the light diffusion pattern P does not need to be maintained constant, and the width may change along the longitudinal direction L of the light guide body 1. The depth of the groove and the opening width of the groove can also be changed as appropriate. The dot pattern does not have to have a constant area density, and the area density may be arbitrarily changed in the main scanning direction and the sub-scanning direction.

The cover member 2 has an elongated shape along the longitudinal direction L of the light guide body 1, and the light diffusion of the light guide body 1 so as to cover the bottom side surface 1a and the left and right side surfaces 1b, 1c of the light guide body 1. It has a bottom surface 2a facing the pattern forming surface 1g, a right side surface 2b facing the right side surface 1b of the light guide body 1, and a left side surface 2c facing the left side surface 1c of the light guide body 1. Since each of these three side surfaces forms a flat surface and a recess having a substantially rectangular cross section is formed on the inner surface of these three surfaces, the light guide body 1 can be inserted into the recess. In this covered state, the bottom surface 2a of the cover member 2 is in close contact with the bottom side surface 1a of the light guide body 1 via the air layer, and the right side surface 2b of the cover member 2 is in close contact with the right side surface 1b of the light guide body 1. The left side surface 2c is in close contact with the left side surface 1c of the light guide body 1 via an air layer. Therefore, the cover member 2 can protect the light guide body 1.

The cover member 2 is not limited to a transparent cover, and may be translucent or opaque. For example, the cover member 2 is a molded product of white resin having high reflectance or a white resin thereof in order to reflect the light leaking from the side surface other than the light emitting side surface 1d of the light guide body 1 again into the light guide body 1. It may be a molded product of a resin coated with. Alternatively, the cover member 2 may be formed of a metal body such as stainless steel or aluminum.

The first light source 3 is mounted on the substrate 6. The first light source 3 is an ultraviolet light source that emits ultraviolet light with respect to the light guide body 1, and an ultraviolet light LED light source having a diameter of 300 nm to 400 nm or the like can be used. As the first light source 3, a lens-molded ultraviolet light emitting diode having a peak emission wavelength in the range of 330 nm to 380 nm is preferably used. A ceramic substrate is used as the substrate of the ultraviolet light emitting diode, and ultraviolet rays can be reflected with high efficiency.

The second light source 4 is mounted on the substrate 7. The second light source 4 is a light source that emits visible light or light having a wavelength ranging from visible to infrared, and is, for example, a surface-mounted LED (Light) that emits light having each wavelength of near infrared, red, green, and blue. Emitting Diode) is used. Further, when emitting white light in which red, green, and blue are mixed, the three colors of red, green, and blue may be turned on at the same time. A resin molded circuit board that reflects visible light and near-infrared rays with high efficiency is used for the surface mount type LED.

Terminals 30 are formed on each of the substrate 6 and the substrate 7, and by inserting the terminals 30 into the substrate 5 and joining them by soldering or the like, each of the first light source 3 and the second light source 4 is driven. It is electrically connected to a power source (not shown). As the drive power source, the first light source 3 and the second light source 4 can be simultaneously or temporally selected by selecting an electrode terminal that applies a voltage to the first light source 3 and an electrode terminal that applies a voltage to the second light source 4. It has a circuit configuration that can be switched to and emit light.

With the above configuration, in a compact configuration, ultraviolet light can be incident on the light guide body 1 from the end surface 1f where the first light source 3 is installed, and visible light or visible light or visible light from the end surface 1e where the second light source 4 is installed. , Light in a wavelength range including visible light to infrared light can be incident on the light source 1. As a result, the light emitted from the first light source 3 or the light emitted from the second light source 4 is refracted and diffused by the light diffusion pattern P, and emitted from the light emitting side surface 1d of the light guide body 1. can do.

Further, in the line light source 10, the first tubular member 8 is attached to one end surface of the light guide body 1, and the second tubular member 9 is attached to the other end surface of the light guide body 1. ing. The substrate 6 is attached to an end surface (one end surface) of the first cylindrical member 8 opposite to the light guide body 1. The substrate 7 is attached to an end surface (the other end surface) of the second tubular member 9 on the side opposite to the light guide body 1. As shown in FIG. 5, a first optical filter 18 is provided in the first tubular member 8, and a second optical filter 19 is provided in the second tubular member 9. The detailed configuration of the first cylindrical member 8 and the second tubular member 9 will be described later.

The first optical filter 18 faces the end surface 1f of the light guide body 1, and the second optical filter 19 faces the end surface 1e of the light guide body 1.
The first optical filter 18 is an optical filter that transmits ultraviolet light of less than 400 nm and blocks visible light of 420 nm or more by reflecting or absorbing it.

The second optical filter 19 is an optical filter that transmits visible light of 420 nm or more and blocks ultraviolet light of less than 400 nm by reflecting or absorbing it.
The first optical filter 18 and the second optical filter 19 are not particularly limited, and may be of any material and structure as long as they block the target wavelength range. For example, in the case of an optical filter that reflects light, an interference filter (bandpass filter) obtained by laminating a thin film of a metal oxide or a dielectric having different transmittances and refractive indexes on the glass surface is preferable.

For example, silicon oxide and tantalum pentoxide are used as the interfering filter to reflect, and the desired bandpass filter characteristics are secured by performing multi-layer deposition by adjusting the transmittance, refractive index and film thickness of each. can get. As a matter of course, there is no particular limitation in adoption as long as it is a bandpass filter conventionally produced for ordinary optical-related industries and satisfies the required performance.

When an interference filter is used for the first optical filter 18 and the second optical filter 19, if the target transmission region cannot be adjusted only by the interference filter, a metal or an oxide thereof, a nitride, or a fluoride thereof is further applied. It is possible to secure the desired wavelength characteristics by stacking films using the thin film of.

If the second optical filter 19 is an optical filter that absorbs ultraviolet light, it may be an ultraviolet light absorbing film in which an organic ultraviolet light absorber is mixed or coated in a transparent film. In addition, for example, silicon oxide and titanium oxide are used as interference filters, and the transmittance, refractive index, and film thickness of each are adjusted to achieve multi-layer deposition, thereby blocking ultraviolet light by both reflecting and absorbing functions. The desired wavelength characteristic may be secured.

Further, if the first optical filter 18 is an optical filter that absorbs visible light, a substance that allows ultraviolet light to pass through and cuts visible light may be added to the film.
The method of installing the first optical filter 18 and the second optical filter 19 on the light guide body 1 is arbitrary, and may be formed by coating or vapor deposition on the end faces 1f, 1e of the light guide body 1. Further, a film-shaped or plate-shaped first optical filter 18 and a second optical filter 19 are prepared and attached to the end faces 1e and 1f of the light guide body 1 or attached at a certain distance from the end faces 1e and 1f. You may.

Further, each of the first optical filter 18 and the second optical filter 19 can be provided in each of the first light source 3 and the second light source 4. In this case, the first optical filter 18 and the second optical filter 19 may be formed on the light sources 3 and 4 by coating or vapor deposition, or the film-shaped or plate-shaped first optical filter 18 and the second optical filter 19 may be formed. It may be prepared and attached in close contact with each of the light sources 3 and 4. Alternatively, the first optical filter 18 may be configured by adding a substance that transmits ultraviolet light and blocks visible light to the sealing agent of the first light source 3. Similarly, the second optical filter 19 may be configured by adding a substance that transmits visible light and blocks ultraviolet light to the sealant of the second light source 4.

If the first optical filter 18 is an optical filter that transmits ultraviolet light and reflects or absorbs visible light, it has the following advantages. It is assumed that the first light source 3 employs a mounting substrate such as an aluminum oxide / ceramics sintered body that emits fluorescence in the vicinity of a wavelength of 690 nm when exposed to ultraviolet light. When ultraviolet light is emitted from the first light source 3, it is necessary to prevent the irradiation light from hitting the mounting substrate of the first light source 3 and being secondarily irradiated with fluorescence near 690 nm to enter the light guide body 1. be. Therefore, if the first optical filter 18 is designed so as to reflect or absorb visible light so that the fluorescence secondarily irradiated does not enter the light guide body 1, the light of the light guide body 1 is prevented. It is possible to prevent unnecessary emission of fluorescence from the emission side surface 1d, and it is possible to improve the contrast of ultraviolet fluorescence of paper leaves. It should be noted that not only the aluminum oxide / ceramics sintered body that fluoresces the ultraviolet light but also the case where the sealing resin fluoresces can prevent the secondary irradiation.

If the second optical filter 19 is an optical filter that transmits visible light and reflects or absorbs ultraviolet light, it has the following advantages. It is assumed that the second light source 4 employs a mounting substrate such as an aluminum oxide / ceramics sintered body that emits fluorescence in the vicinity of a wavelength of 690 nm when exposed to ultraviolet light. When the ultraviolet light emitted from the first light source 3 passes through the end surface 1e of the light guide body 1 and hits the second light source 4, fluorescence near 690 nm is secondarily irradiated from the second light source 4 and inside the light guide body 1. You need to prevent this as it comes in. Therefore, if the second optical filter 19 is designed to reflect or absorb the ultraviolet light so that the ultraviolet light does not come out from the end surface 1e of the light guide body 1, it does not hit the second light source 4. .. Therefore, it is possible to prevent unnecessary fluorescence from being emitted from the light emitting side surface 1d of the light guide body 1. As a result, the contrast of ultraviolet fluorescence of paper leaves can be improved.

If the first optical filter 18 is an optical filter that transmits ultraviolet light and reflects visible light, it is irradiated from the second light source 4, incident on the light guide body 1, and reflected by the first optical filter 18 to guide the light. Since the amount of visible light returning to the body 1 increases, as a result, the effect of increasing the amount of visible light emitted from the light emitting side surface 1d of the light guide body 1 can be obtained. Further, since the first optical filter 18 transmits the ultraviolet light emitted from the first light source 3, the ultraviolet light can be emitted from the light emitting side surface 1d of the light guide body 1.

Further, an optical filter in which the second optical filter 19 transmits visible light and reflects ultraviolet light is preferable, and has the following advantages. Since the amount of ultraviolet light incident on the light guide 1 from the first light source 3 and reflected by the second optical filter 19 and returning to the light guide 1 increases, as a result, the ultraviolet light from the light emitting side surface 1d of the light guide 1 increases. The effect of increasing the amount of emitted light can be obtained. In this case, since the second optical filter 19 transmits the visible light emitted from the second light source 4, it does not prevent the visible light from the second light source 4 from entering the light guide body 1.

In the line light source 10, the ultraviolet light emitted from the first light source 3 is incident on the light guide body 1 via the first optical filter 18, diffused and refracted by the light diffusion pattern forming surface 1g, and the light emission side surface 1d. Is irradiated to the paper leaves (medium) on the focal plane 20. As a result, fluorescence is generated from the paper leaves, and the fluorescent color emission is detected by the light receiving unit 12, so that the paper leaves can be identified using ultraviolet light.

Further, visible light emitted from the second light source 4 or light having a wavelength ranging from visible to infrared rays enters the light guide body 1 via the second optical filter 19, and is diffused / refracted by the light diffusion pattern forming surface 1g. Then, the paper leaves (medium) on the focal plane 20 are irradiated from the light emitting side surface 1d. This makes it possible to identify paper sheets using visible light or light having a wavelength ranging from visible to infrared.

<Light receiving part>
The light receiving unit 12 is formed by arranging a plurality of light receiving elements (consisting of a photodiode, a phototransistor, etc.) arranged linearly in the y direction and mounting them on a substrate. The type of the light receiving element is not limited, and for example, a silicon PN diode or a PIN diode is used.

By exposing the light receiving elements arranged in a row while the paper leaves move in the x direction (secondary scanning direction), the surface of the paper leaves has a predetermined width along the y direction (main scanning direction). Observation lines can be set. The exposure time (referred to as optical reading time) for reading the line information of paper sheets can be arbitrarily set according to the intensity of the light source, the wavelength sensitivity of the sensor, and the like. For example, the moving speed of paper sheets in the x direction is 1500 to 2000 mm / sec in an ATM or a banknote processor, and if 0.5 to 1.0 ms is adopted as the optical reading time, the x of the observation line The width in the direction is 0.75 to 2 mm.

<Cylindrical member and angle conversion reflector>
FIG. 6 is a side sectional view of one end of the line light source 10.
As described above, in the line light source 10, the first cylindrical member 8 is arranged so as to face one end surface 1f of the light guide body 1. A substrate 6 on which the first light source 3 is mounted is attached to the first tubular member 8. Further, inside the first tubular member 8, an angle conversion reflecting unit 40 is provided together with the first optical filter 18.

The first tubular member 8 is formed in a cylindrical shape. The central axis of the first tubular member 8 coincides with the central axis of the light guide body 1. That is, the first cylindrical member 8 and the light guide body 1 share the central axis A. The inner diameter of the first tubular member 8 increases from one end (right end in FIG. 6) toward the other end. That is, the inner peripheral surface 81 of the first cylindrical member 8 is formed in a tapered shape that expands from one end edge toward the other end edge. The inner peripheral surface 81 of the first tubular member 8 is formed as a reflecting surface that reflects light.

Further, the internal space of the first tubular member 8 is the mixing space 50. The mixing space 50 is formed so that the cross-sectional area becomes at least equal to or larger than the area of the end portion on the side of the first light source 3 as the distance from the first light source 3 increases. Specifically, the mixing space 50 is formed so that the cross-sectional area increases as it approaches the light guide body 1 (as it moves away from the first light source 3).
The substrate 6 is attached to one end surface (right end surface in FIG. 6) of the first cylindrical member 8. The first light source 3 is provided on the surface of the substrate 6 facing the light guide body 1 (the surface on the side of the first tubular member 8). The first light source 3 is covered with a resin molded lens 31.

The first optical filter 18 is provided in the internal space at the other end of the first cylindrical member 8. In other words, the first optical filter 18 is arranged on the other side (light guide body 1 side) in the mixing space 50. The first optical filter 18 faces the end surface 1f of the light guide body 1.
The angle conversion reflection unit 40 is arranged in the first cylindrical member 8 (mixing space 50), and is arranged between the first light source 3 and the first optical filter 18.

FIG. 7 is a front view of the angle conversion reflecting unit 40. FIG. 7 shows a state in which the angle conversion reflecting unit 40 is viewed from a direction along the central axis A.
As shown in FIGS. 6 and 7, the angle conversion reflection unit 40 includes an annular portion 401, a shielding portion 402, and a holding portion 403.

The annular portion 401 has a certain thickness and is formed in an annular shape.
The shielding portion 402 is arranged inside the annular portion 401. The shielding portion 402 has an elliptical front view shape and has a structure in which the thickness increases toward the center. The surface of the shielding portion 402 is formed as a reflecting surface that diffusely reflects or changes the angle of light with high efficiency.

The shielding portion 402 is formed of a so-called curved surface, but has various forms such as an aspherical surface, a spherical surface, or a combination of an aspherical surface and a spherical surface. It is decided in consideration of the effect of suppressing the light, light utilization efficiency, distance characteristics, cost, and the like. Further, it does not necessarily have to be a curved surface, and may be a polyhedron, a combination of various polyhedra, or a simple flat plate. In short, the shape may be determined in consideration of various parameters so that the light emitted from the light source is not directly incident on the light diffusion pattern in the vicinity of the incoming light portion.

For example, the surface of the shielding portion 402 of the angle conversion reflecting unit 40 is composed of a curved surface or a combination of different types of curved surfaces, and has a diffuse reflection function, a specular reflection function, or an angle conversion function by reflection including diffuse reflection and specular reflection. May be.
Further, the surface of the shielding portion 402 of the angle conversion reflecting unit 40 is composed of a plane or a combination of planes having different angles, and has a diffuse reflection function, a mirror reflection function, or an angle conversion function by reflection including diffuse reflection and mirror reflection. It may be a thing.
Further, the surface of the shielding portion 402 of the angle conversion reflecting unit 40 is composed of a combination of a flat surface and a curved surface, and has a diffuse reflection function, a mirror surface reflection function, or an angle conversion function by reflection including diffuse reflection and mirror surface reflection. May be good.

The holding portion 403 extends in a rod shape from a plurality of locations on the outer edge of the shielding portion 402 toward the inner edge of the annular portion 401. The holding portion 403 holds the shielding portion 402 in a state of being located inside the annular portion 401.
In the angle conversion reflection unit 40, the region other than the annular portion 401, the shielding portion 402, and the holding portion 403 is the incident region 404 on which the light from the first light source 3 is incident. When the area of the incident region 404 in the front view (state shown in FIG. 7) is D, and the area of the annular portion 401, the shielding portion 402, and the holding portion 403 in the front view (state shown in FIG. 7) is S, 8 The relational expression <(D + S) / S <12 is satisfied. The area of the annular portion 401, the shielding portion 402, and the holding portion 403 in the front view is the projected area of the angle conversion reflecting portion 40 with respect to the end surface 1f of the light guide body 1.

The angle conversion reflecting portion 40 is arranged in the mixing space 50 by attaching the annular portion 401 to the inner peripheral surface 81 of the first tubular member 8. The angle conversion reflection unit 40 is close to the first optical filter 18 in the mixing space 50. The shielding portion 402 of the angle conversion reflecting portion 40 is arranged on the lower side in the mixing space 50, and is arranged on the lower side (light diffusion pattern P side) than the central axis A. The shielding portion 402 is arranged on the main optical path B connecting one end portion (end portion on the first light source 3 side) of the light diffusion pattern P and the first light source 3.

The shielding portion 402 includes the refractive index of the light guide body 1 connecting any one point at both ends of the light diffusion pattern P near the light entering portion in the main scanning direction and any one point of the first light source 3, and a mold lens type. In the case of an LED, it is arranged at a position that shields a region surrounded by a group of light rays having a certain three-dimensional angle determined by the relationship including the refractive index of the lens, and is directly applied to the light diffusion pattern P in the vicinity of the light entrance portion of the light guide body 1. It has a size that does not allow it to enter. The center of the shielding portion 402 is arranged on the main optical path B connecting one end portion (the end portion on the first light source 3 side) of the light diffusion pattern P and the first light source 3.

FIG. 8 is a side sectional view of the other end of the line light source 10.
In the line light source 10, the second tubular member 9 is arranged so as to face the other end surface 1e of the light guide body 1. A substrate 7 on which the second light source 4 is mounted is attached to the second tubular member 9. Further, inside the second tubular member 9, an angle conversion reflecting unit 60 is provided together with the second optical filter 19.

The second tubular member 9 is formed in a cylindrical shape having a thickness thinner than that of the first tubular member 8 in the optical axis direction. The central axis of the second tubular member 9 coincides with the central axis of the light guide body 1. That is, the second tubular member 9 and the light guide body 1 share the central axis A. The inner diameter of the second tubular member 9 increases from the other end (right end in FIG. 8) toward one end. That is, the inner peripheral surface 91 of the second tubular member 9 is formed in a tapered shape that expands from the edge on the side of the second light source 4 toward the edge on the light receiving portion side of the light guide body 1. The inner peripheral surface 91 of the second tubular member 9 is formed as a reflecting surface that reflects light.

Further, the internal space of the second tubular member 9 is the mixing space 53. The mixing space 53 is formed so that the cross-sectional area becomes at least equal to or larger than the area of the end portion on the side of the second light source 4 as the distance from the second light source 4 increases. Specifically, the mixing space 53 is formed so that the cross-sectional area increases as it approaches the light guide body 1 (as it moves away from the second light source 4).
The substrate 7 is attached to the other end surface (right end surface in FIG. 8) of the second cylindrical member 9. The second light source 4 is provided on the surface of the substrate 7 facing the light guide body 1 (the surface on the side of the second tubular member 9). The second light source 4 is a surface mount type LED, and includes a white light source 41 and a plurality of monochromatic light sources 42.

The white light source 41 is arranged slightly above the central portion of the substrate 7, and the monochromatic light source 42 is arranged slightly below the central portion of the substrate 7.
The white light source 41 is a white LED light source that generates white light (W).
The monochromatic light source 42 is a monochromatic LED light source that generates monochromatic light. In FIG. 8, only one monochromatic light source 42 is shown, but in reality, a plurality of (for example, three) monochromatic light sources 42 are provided.

The second optical filter 19 is provided in the internal space of one end of the second tubular member 9. In other words, the second optical filter 19 is arranged on one side (light guide body 1 side) in the mixing space 53. The second optical filter 19 faces the end surface 1e of the light guide body 1.
The angle conversion reflection unit 60 is arranged in the second tubular member 9 (mixing space 53), and is arranged between the second light source 4 and the second optical filter 19.

FIG. 9 is a front view of the angle conversion reflecting unit 60. FIG. 9 shows a state in which the angle conversion reflecting unit 60 is viewed from a direction along the central axis A.
As shown in FIGS. 8 and 9, the angle conversion reflecting unit 60 includes an annular portion 601, a first shielding portion 602, a second shielding portion 603, and a holding portion 604.

The annular portion 601 has a certain thickness and is formed in an annular shape.
The first shielding portion 602 is arranged slightly upward on the inner side of the annular portion 601. The first shielding portion 602 has an elliptical front view shape. The surface of the first shielding portion 602 is formed as a reflecting surface that diffusely reflects or changes the angle of light with high efficiency.

The second shielding portion 603 is arranged slightly downward on the inner side of the annular portion 601. The second shielding portion 603 is arranged below the first shielding portion 602 at intervals. The second shielding portion 603 has an elliptical front view shape. The surface of the second shielding portion 603 is formed as a reflecting surface that diffusely reflects or changes the angle of light with high efficiency. Each of the first shielding portion 602 and the second shielding portion 603 has a structure in which the thickness increases toward the center.

Each of the first shielding unit 602 and the second shielding unit 603 can take various forms like the shielding unit 402 of the angle conversion reflecting unit 40.
The holding portion 604 extends in a rod shape from a plurality of locations on the outer edge of the first shielding portion 602 and a plurality of locations on the outer edge of the second shielding portion 603 toward the inner edge of the annular portion 601. A part of the holding portion 604 connects the first shielding portion 602 and the second shielding portion 603. The holding portion 604 holds the first shielding portion 602 and the second shielding portion 603 in a state of being located inside the annular portion 601.

In the angle conversion reflection unit 60, the region other than the annular portion 601, the first shielding portion 602, the second shielding portion 603, and the holding portion 604 becomes an incident region 605 to which the light from the second light source 4 is incident. Let D be the area of the incident region 605 in the front view (state shown in FIG. 9), and the areas of the annular portion 601, the first shielding portion 602, the second shielding portion 603, and the holding portion 604 in the front view (state shown in FIG. 9). When S is, the relational expression of 8 <(D + S) / S <12 is satisfied. The area of the annular portion 601, the first shielding portion 602, the second shielding portion 603, and the holding portion 604 in the front view is the projected area of the angle conversion reflecting portion 60 with respect to the end surface 1e of the light guide body 1.

The angle conversion reflecting portion 60 is arranged in the mixing space 53 by attaching the annular portion 601 to the inner peripheral surface 91 of the second tubular member 9. The angle conversion reflection unit 60 is close to the second optical filter 19 in the mixing space 53. The first shield portion 602 of the angle conversion reflection unit 60 is arranged in the central portion in the mixing space 53, and the second shield portion 603 of the angle conversion reflection unit 60 is arranged on the lower side in the mixing space 53. It is arranged on the lower side (light diffusion pattern P side) than the central axis A. The first shielding portion 602 is arranged on the main optical path C connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the white light source 41. The second shielding portion 603 is arranged on the main optical path D connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the monochromatic light source 42.

Each of the first shielding unit 602 and the second shielding unit 603 is a light guide body connecting an arbitrary point at both ends of the light diffusion pattern P in the vicinity of the light entering portion in the main scanning direction and an arbitrary point of the second light source 4. In the case of a molded lens type LED, it is arranged at a position that shields a region surrounded by a group of light rays having a certain stereoscopic angle, which is determined by the relationship including the refraction coefficient of 1 and the light guide body 1 is inserted. It has a size that does not directly incident on the light diffusion pattern P in the vicinity of the light portion. The center of the first shielding portion 602 is arranged on the main optical path C connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the white light source 41. The center of the second shielding portion 603 is arranged on the main optical path D connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the monochromatic light source 42.
The angle conversion reflecting units 40 and 60 have a diffuse reflection, a mirror surface reflection, or an angle conversion function by reflection including diffuse reflection and specular reflection.

When ultraviolet light is emitted from the first light source 3 in the line light source 10, most of the ultraviolet light passes through the incident region 404 of the angle conversion reflecting unit 40 and further passes through the first optical filter 18. It is incident on the inside of the light guide body 1 from the end surface 1f of the light guide body 1.

On the other hand, among the ultraviolet light emitted from the first light source 3, the ultraviolet light directed to one end (the end on the first light source 3 side) in the light diffusion pattern P is generated by the shielding portion 402 of the angle conversion reflecting portion 40. Diffuse reflection or angle conversion. Specifically, among the ultraviolet light emitted from the first light source 3, the ultraviolet light directed to one end (the end on the first light source 3 side) in the light diffusion pattern P is shielded by the angle conversion reflecting unit 40. It is reflected by the surface of the portion 402 and heads toward the inside of the mixing space 50. Then, the reflected light is reflected again on the inner peripheral surface 81 of the first tubular member 8. At this time, the ultraviolet light re-enters the angle-converting reflection unit 40, diffusely reflects, and again heads toward the light entry portion end surface 1f of the light guide body 1 and re-enters the angle-converting reflection unit 40. There is also light directed from the incident region 404 of the angle conversion reflecting unit 40 toward the end surface 1f of the light guide body 1. In this way, while reciprocating between the angle conversion reflecting unit 40 and the first light source 3, the light increasing from the incident region 404 of the angle conversion reflecting unit 40 toward the end surface 1f of the light input portion of the light guide body 1. Then, the light passes through the first optical filter 18 and is incident on the inside of the light guide body 1 from the end surface 1f of the light guide body 1.

Then, the ultraviolet light incident on the inside of the light guide body 1 is reflected a plurality of times on the inner surface of the light guide body 1, then diffused by the light diffusion pattern P, and is emitted from the light emission side surface 1d.

Further, in the line light source 10, when visible light or light having a wavelength ranging from visible to infrared is emitted from the second light source 4, most of the light passes through the incident region 605 of the angle conversion reflecting unit 60, and further. , It passes through the second optical filter 19 and is incident on the inside of the light guide body 1 from the end surface 1e of the light source body 1.

On the other hand, among the visible light emitted from the second light source 4 or the light having a wavelength ranging from visible to infrared, the light directed to the other end (the end on the second light source 4 side) in the light diffusion pattern P is an angle. It is reflected by the surfaces of the first shielding portion 602 and the second shielding portion 603 of the conversion reflecting portion 60, and heads toward the inside of the mixing space 53 of the second tubular member 9. Then, the reflected light is reflected again on the inner peripheral surface 91 of the second tubular member 9, re-entered on the angle conversion reflecting portion 60, diffusely reflected, and again on the light input portion end surface 1e of the light guide body 1. Some light faces and re-enters the angle-converting reflecting unit 60, and some light goes from the incident region 605 of the angle-converting reflecting unit 60 toward the end face 1e of the light guide body 1. In this way, while reciprocating between the angle conversion reflection unit 60 and the second light source 4, the light from the incident region 605 of the angle conversion reflection unit 60 toward the end surface 1e of the light input portion of the light guide body 1 increases. Then, the light passes through the second optical filter 19 and is incident on the inside of the light guide body 1 from the end surface 1e of the light guide body 1.
Then, the visible light incident on the inside of the light guide body 1 or the light having a wavelength ranging from visible to infrared rays is reflected a plurality of times on the inner surface of the light guide body 1 and then diffused by the light diffusion pattern P to emit light. Emit from 1d.

As described above, in the line light source 10, among the ultraviolet light emitted from the first light source 3, the ultraviolet light directed to one end (the end on the first light source 3 side) in the light diffusion pattern P is reflected by angle conversion. It is diffusely reflected or angle-converted by the shielding portion 402 of the portion 40. Similarly, among the visible light emitted from the second light source 4 or the light having a wavelength ranging from visible to infrared, the light directed to the other end (the end on the second light source 4 side) in the light diffusion pattern P is Angle conversion Reflection reflection or angle conversion is performed by the first shielding unit 602 and the second shielding unit 603 of the reflecting unit 60. Therefore, it is possible to suppress that the light emitted from each of the first light source 3 and the second light source 4 is directly incident on the light diffusion pattern P.

FIG. 10 is a graph showing the intensity distribution of light with respect to paper sheets in the optical licensor unit. In FIG. 10, the horizontal axis represents the position in the main scanning direction, and the vertical axis represents the light intensity. In the optical licensor unit corresponding to each graph of FIG. 10, only one light source in the line light source is provided for convenience. In FIG. 10, it is shown that the smaller the numerical value (on the left side), the closer the position is to the light source on the horizontal axis.

In FIG. 10, graph B2 shows the intensity distribution of light in a conventional optical licensor unit. Specifically, in the optical licensor unit showing the light intensity distribution of the graph B2, the tubular member is not provided with the angle conversion reflecting portion. Further, in FIG. 10, graph B1 shows the light intensity distribution of another conventional optical line sensor unit. Specifically, in the optical line sensor unit corresponding to the graph B1, the diaphragm is inserted for the purpose of selectively injecting a component close to the parallel luminous flux into the light guide body, and the angle conversion reflection unit is not provided. ..

From the graphs B1 and B2, it can be confirmed that when the line light source is not provided with the angle conversion reflection unit, the intensity of the light emitted from the line light source at a position close to the light source becomes extremely strong.

In FIG. 10, graphs A1, A2, and A3 show the intensity distribution of light in the optical licensor unit (optical licensor unit provided with the line light source 10) of the present invention. Graph A1 shows the light intensity distribution in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is large. Graph A3 shows the light intensity distribution in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is small. In the graph A2, when the projected area of the angle conversion reflecting unit 40 is larger than the unit of the graph A3 and smaller than the unit of the graph A1 (when the size of the projected area of the angle conversion reflecting unit 40 is medium). The light intensity distribution in the optical licensor unit of is shown. That is, when comparing the sizes of the projected areas of the angle conversion reflecting unit 40 in the line light source 10, A3 <A2 <A1.

From the graphs A1, A2, and A3, when the line light source 10 provided with the angle conversion reflecting unit 40 is used, the rapid increase in the light intensity at the end on the light source side is improved (the light intensity distribution is made uniform). ) Can be confirmed. Further, it can be confirmed that the larger the projected area of the angle conversion reflecting unit 40, the higher the uniformity (flatness) of the light intensity.

For this reason, in the optical licensor unit, it is effective to provide an angle conversion reflecting portion on the main light path connecting the end portion and the light source in the light diffusion pattern, as in the line light source 10, from the viewpoint of uniformity of light intensity. It turns out that.

FIG. 11A is a graph showing a three-dimensional light intensity distribution in a conventional optical licensor unit. FIG. 11B is a graph showing the light intensity distribution in another conventional optical line sensor unit in three dimensions. In the optical licensor unit corresponding to FIG. 11A, the cylindrical member is not provided with the angle conversion reflecting portion. Further, in the optical line sensor unit corresponding to FIG. 11B, the tubular member is not provided with an angle conversion reflecting unit, and the diaphragm is used for the purpose of selectively injecting a component close to a parallel luminous flux into the light guide body. It has been put in.

11C to 11E are graphs showing the intensity distribution of light in the optical licensor unit (optical licensor unit provided with the line light source 10) of the present invention in three dimensions. Specifically, the graph of FIG. 11C shows three-dimensionally the light intensity distribution in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is large. The graph of FIG. 11E shows three-dimensionally the light intensity distribution in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is small. In the graph of FIG. 11D, when the projected area of the angle conversion reflecting unit 40 is larger than the unit of the graph of FIG. 11E and smaller than the unit of the graph of FIG. 11C (the size of the projected area of the angle conversion reflecting unit 40). The light intensity distribution in the optical licensor unit (when is medium) is shown.

In the figures on the left side of FIGS. 11A to 11E, the vertical axis represents the light intensity, the axis orthogonal to the paper surface represents the position in the main scanning direction, and the horizontal axis represents the secondary axis. It represents the position in the scanning direction. Further, the graphs on the right side of FIGS. 11A to 11E are viewed more three-dimensionally by changing the angle of the graph on the left side. The position is shown on the opposite side of the light entrance.
In the optical licensor unit corresponding to the graphs of FIGS. 11A to 11E, for convenience, only one light source in the line light source is provided. In FIGS. 11A to 11E, it is shown that the farther the side is, the closer the position is to the light source side.

From FIGS. 11A and 11B, it can be confirmed that when the line light source is not provided with the angle conversion reflection unit, the intensity of the light emitted from the line light source at a position close to the light source becomes extremely strong.
From FIGS. 11C to 11E, when the line light source 10 provided with the angle conversion reflecting unit 40 is used, the rapid increase in the light intensity at the end portion on the light source side is improved (the uniformity of the light intensity is increased). Can be confirmed. Further, as shown in FIG. 11C, it can be confirmed that the larger the projected area of the angle conversion reflecting unit 40, the higher the uniformity of the light intensity.

Further, in the graphs of FIGS. 11C to 11E, the width of the position where the light of increased intensity with increased uniformity is emitted is larger in the sub-scanning direction (axis in the left-right direction) than in the graph of FIG. 11B. Can be confirmed. Further, it can be seen that the uniformity of the light intensity in the sub-scanning direction is the same as that of FIG. 11A, and the increase in the light intensity in the vicinity of the light input portion of the light guide body 1 is small. In this way, if the increase in the light intensity in the vicinity of the light input portion of the light guide body 1 can be suppressed, and at the same time, the portion where the light having the increased uniformity intensity is emitted in the sub-scanning direction becomes large, the sub-scanning direction is reached. Even when the focal position of the light and the relative position of the paper leaves are slightly deviated due to blurring of the paper leaves to be sent out, the light can be emitted with a uniform light intensity in the main scanning direction. That is, by providing the angle conversion reflecting portion in the line light source, the increase in the light intensity in the vicinity of the light input portion of the light guide body 1 is suppressed, and at the same time, the allowable range of the deviation between the focal position of the light and the relative position of the paper sheets is adjusted. Can be made larger (improves distance characteristics).

FIG. 12 is a graph showing the utilization efficiency of light in the optical licensor unit. In FIG. 12, graphs b1 and b2 represent the efficiency of light utilization in a conventional optical licensor unit. The lowercase numbers in FIG. 12 and the uppercase numbers in FIG. 10 correspond to each other. In FIG. 12, graphs a1 to a3 represent the efficiency of light utilization in the optical licensor unit of the present invention. Specifically, graph a1 shows the efficiency of light utilization in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is large. Graph a3 shows the efficiency of light utilization in the optical licensor unit when the projected area of the angle conversion reflecting unit 40 is small. In the graph a2, when the projected area of the angle conversion reflecting unit 40 is larger than the unit of the graph a3 and smaller than the unit of the graph a1 (when the size of the projected area of the angle conversion reflecting unit 40 is medium). The light intensity distribution in the optical licensor unit of is shown.

From these graphs, when the line light source 10 provided with the angle conversion reflecting unit 40 having a large projected area is used (in the case of a1), the light is used as compared with the case where the conventional line light source is used (in the case of b2). It can be seen that the efficiency decreases slightly, but the amount of decrease is small. Further, when the line light source 10 including the angle conversion reflecting unit 40 having a medium projected area is used (in the case of a2), and when the line light source 10 including the angle conversion reflecting unit 40 having a small projected area is used (a3). In the case of), it can be seen that the light utilization efficiency is increased as compared with the case of using the conventional line light source (in the case of b1 and b2). In particular, it can be seen that it is effective to use the line light source 10 (a3) provided with the angle conversion reflecting unit 40 having a small projected area from the viewpoint of light utilization efficiency. Further, it can be seen that the light utilization efficiency is higher in all cases of a1 to a3 provided with the angle conversion reflecting portion than in the case of b1 which is another conventional line light source (when there is a diaphragm).

In the above-mentioned line light source 10, the end portion in the light diffusion pattern P is, for example, from the edge of the light diffusion pattern P with respect to the entire dimension (length) of the light diffusion pattern P in the long direction. This is a portion where the dimension (length) is 0.5 to 5%.
Further, the end portion in the light diffusion pattern P is, for example, a portion where the dimension (length) from the edge of the light diffusion pattern P is 1 to 10 mm.
With such a configuration, it is possible to effectively realize uniform light intensity in the optical licensor unit.

<Action effect>
In the present embodiment, as shown in FIGS. 6 and 8, the line light source 10 includes angle conversion reflecting units 40 and 60. At one end of the line light source 10, the shielding portion 402 of the angle conversion reflecting portion 40 is provided on the main optical path B connecting the end on the first light source 3 side in the light diffusion pattern P and the first light source 3. Further, at the other end of the line light source 10, the first shielding portion 602 of the angle conversion reflecting portion 60 includes the other end of the light diffusion pattern P (the end on the second light source 4 side) and the white light source 41. It is provided on the main optical path C connecting the above. The second shielding portion 603 of the angle conversion reflecting portion 60 is provided on the main optical path D connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the monochromatic light source 42.

Therefore, among the ultraviolet light emitted from the first light source 3, the ultraviolet light directly directed to the end on the first light source 3 side in the light diffusion pattern P without being reflected by the inner surface of the light guide body 1 is angle-converted reflection. It is diffusely reflected or angle-converted by the shielding portion 402 of the portion 40. Similarly, of the visible light emitted from the second light source 4 or the light having a wavelength ranging from visible to infrared, the end on the second light source 4 side in the light diffusion pattern P without being reflected by the inner surface of the light guide body 1. The light directly directed to the unit is diffusely reflected or angle-converted by the first shielding unit 602 and the second shielding unit 603 of the angle conversion reflecting unit 60.

As a result, the amount of ultraviolet light emitted from the first light source 3 and directly incident on the light diffusion pattern P in the vicinity of the light entrance portion of the light guide body 1 can be adjusted or reduced. Then, it is possible to prevent the intensity of the light diffused by the light diffusion pattern from becoming extremely high in the vicinity of the light entering portion. Similarly, the amount of visible light emitted from the second light source 4 and directly incident on the light diffusion pattern P in the vicinity of the light inlet portion of the light guide body 1 or light having a wavelength ranging from visible to infrared can be adjusted or reduced. .. Then, it is possible to prevent the intensity of the light diffused by the light diffusion pattern from becoming extremely high in the vicinity of the light entering portion.
Therefore, it is possible to suppress the non-uniformity of the intensity of the light emitted from the light guide body 1.

Further, in the light guide body 1, the intensity of the emitted light from the light guide body 1 among the ultraviolet light from the first light source 3, the visible light from the second light source 4, and the light having a wavelength ranging from visible to infrared. Only the light that causes the non-uniformity of the light can be diffusely reflected or angle-converted by the angle conversion reflecting unit 40 to adjust or reduce the amount of light without sacrificing the light utilization efficiency.
As described above, according to the line light source 10, the non-uniformity of the intensity of the light emitted from the light guide body 1 can be suppressed, and the decrease in the light utilization efficiency can be suppressed.

Further, in the present embodiment, the angle conversion reflecting units 40 and 60 have a diffuse reflection, a mirror surface reflection, or an angle conversion function by reflection including diffuse reflection and specular reflection.
Therefore, it is possible to reliably prevent the light emitted from each of the first light source 3 and the second light source 4 from directly incident on the diffusion pattern P.

Further, in the present embodiment, among the ultraviolet light emitted from the first light source 3, the ultraviolet light reflected by the angle conversion reflecting unit 40 is reflected by the inner peripheral surface 81 of the first tubular member 8 that partitions the mixing space 50. Then, while reciprocating between the first light source 3 and the shielding portion 402 of the angle conversion reflecting portion 40, the light is finally incident on the inside of the light guide body 1. Similarly, of the visible light emitted from the second light source 4 or the light having a wavelength ranging from visible to infrared, the light reflected by the angle conversion reflecting unit 60 is reflected by the inner peripheral surface 91 of the second tubular member 9. Then, while reciprocating between the second light source 4 and the first shielding unit 602 and the second shielding unit 603 of the angle conversion reflecting unit 60, the light is finally incident on the inside of the light guide body 1.
Therefore, it is possible to suppress a decrease in utilization efficiency of ultraviolet light emitted from the first light source 3, visible light emitted from the second light source 4, or light having a wavelength ranging from visible to infrared.

Further, in the present embodiment, in the line light source 10, the mixing spaces 50 and 53 are formed so as to face the end faces 1f and 1e of the light guide body 1.
Therefore, the mixing spaces 50 and 53 can be formed at appropriate positions.

Further, in the present embodiment, as shown in FIG. 6, the mixing space 50 formed in the first tubular member 8 has a cross-sectional area of the area of the end portion on the first light source 3 side as the distance from the first light source 3 increases. On the other hand, it is formed so as to have an area of at least the same or larger. Specifically, it is formed so that the cross-sectional area increases as the distance from the first light source 3 increases. Similarly, the mixing space 53 formed in the second tubular member 9 has a cross-sectional area at least equal to or larger than the area of the end portion on the second light source 4 side as the distance from the second light source 4 increases. It is formed. Specifically, the mixing space 53 is formed so that the cross-sectional area increases as the distance from the second light source 4 increases.

Therefore, the efficiency of ultraviolet light reflected by the inner peripheral surface 81 of the first tubular member 8, visible light reflected by the inner peripheral surface 91 of the second tubular member 9, or light having a wavelength ranging from visible to infrared is efficient. It can be often incident on the inside of the light guide body 1.

Further, in the present embodiment, in the line light source 10, the area of the incident regions 404, 605 of the angle conversion reflecting portions 40, 60 is D, and the projected area of the angle conversion reflecting portions 40, 60 with respect to the end face of the light guide body 1 is S. , The relational expression of 8 <(D + S) / S <12 is satisfied.

Therefore, in the line light source 10, the angle conversion reflection unit 40 can be configured to have a size suitable for diffuse reflection or angle conversion of ultraviolet light from the first light source 3. Similarly, in the line light source 10, the angle conversion reflecting unit 60 can be configured to have a size suitable for diffuse reflection or angle conversion of visible light from the second light source 4 or light having a wavelength ranging from visible to infrared.

Further, in the present embodiment, the angle conversion reflecting units 40 and 60 have a diffuse reflection function, a specular reflection function, or a diffuse reflection and a specular reflection, because the surface thereof is, for example, a curved surface or a combination of different types of curved surfaces. It has an angle conversion function by including reflection.

Therefore, the angle conversion reflecting units 40 and 60 can be provided with an angle conversion function by a simple configuration in which the surface shapes of the angle conversion reflecting units 40 and 60 are formed by a curved surface or a combination of different types of curved surfaces.

Further, in the present embodiment, the angle conversion reflecting units 40 and 60 have a diffuse reflection function, a mirror reflection function, or a diffuse reflection and a mirror reflection, because the surface thereof is, for example, a plane or a combination of planes having different angles. It has an angle conversion function by reflection including.

Therefore, the angle conversion reflecting unit can be provided with an angle conversion function by a simple configuration in which the surface shapes of the angle conversion reflecting units 40 and 60 are formed by a plane or a combination of planes having different angles.

Further, in the present embodiment, the surface of the angle conversion reflecting units 40 and 60 is composed of a combination of a plane and a curved surface, so that the surface is a diffuse reflection function, a mirror reflection function, or an angle conversion by reflection including diffuse reflection and mirror reflection. Has a function.

Therefore, the angle conversion reflecting portion can be provided with the angle conversion function by a simple configuration in which the surface shape of the angle conversion reflecting portion is formed by a combination of a flat surface and a curved surface.

Further, in the present embodiment, as shown in FIG. 5, the line light source 10 includes a first light source 3 and a second light source 4 as light sources.

Therefore, it is possible to select light having a wavelength range including ultraviolet light, visible light, or visible light to infrared light, emit the light from the light source, and make the light enter the inside of the light guide body 1.
Therefore, the optimum light can be emitted from the light emitting side surface 1d of the light guide body 1.

Further, in the present embodiment, as shown in FIG. 5, the line light source 10 includes a first optical filter 18 arranged between one end surface 1f of the light guide body 1 and the first light source 3. The first optical filter 18 transmits ultraviolet light and blocks visible light or light in a wavelength range including visible light to infrared light.

Therefore, only the ultraviolet light emitted from the first light source 3 can be transmitted by the first optical filter 18 and incident on the inside of the light guide body 1. For example, when the first light source 3 employs a mounting substrate such as an aluminum oxide ceramic sintered body that emits fluorescence when exposed to ultraviolet light, the irradiation light from the first light source 3 hits the mounting substrate. , Fluorescence will be secondarily irradiated. With the line light source 10 of the present embodiment, the fluorescence secondarily irradiated from the first light source 3 can be prevented from entering the inside of the light guide body 1 by the first optical filter 18.

Further, in the present embodiment, as shown in FIG. 5, the line light source 10 includes a second optical filter 19 arranged between the other end surface 1e of the light guide body 1 and the second light source 4. The second optical filter 19 transmits visible light or light in a wavelength range including visible light to infrared light, and blocks ultraviolet light.

Therefore, only the visible light emitted from the second light source 4 or the light in the wavelength range including the visible light to the infrared light can be transmitted by the second optical filter 19 and incident on the inside of the light guide body 1. For example, when the second light source employs a mounting substrate that emits fluorescence when exposed to ultraviolet light, such as an aluminum oxide ceramic sintered body, the irradiation light from the first light source 3 is the light guide body 1. It passes through the above and hits the mounting substrate of the second light source 4, and is secondarily irradiated with fluorescence. With the line light source 10 of the present embodiment, the ultraviolet light emitted from the first light source 3 can be prevented from being incident on the second light source 4 by the second optical filter 19. Then, it is possible to prevent the second light source 4 from being secondarily irradiated with fluorescence.

Further, in the present embodiment, as shown in FIG. 1, the optical line sensor unit includes a lens array 11 and an ultraviolet light blocking optical filter 15. The ultraviolet light blocking optical filter 15 is provided between the focal plane 20 (paper sheets) and the light receiving unit 12. The ultraviolet light blocking optical filter 15 transmits visible light or light in a wavelength range including visible light to infrared light, and blocks ultraviolet light so that ultraviolet light does not enter the light receiving unit 12.
Therefore, it is possible to prevent the secondary irradiation of fluorescence by ultraviolet light in the vicinity of the light receiving unit 12.

<Second Embodiment>
FIG. 13 is a side sectional view of the line light source 10 according to the second embodiment of the present invention. FIG. 13 shows the periphery of one end of the line light source 10.
In the first embodiment described above, in the line light source 10, the substrate 6 is attached to the first cylindrical member 8, and the substrate 7 is attached to the second tubular member 9.

On the other hand, in the second embodiment, the line light source 10 does not include the first tubular member 8 and the second tubular member 9, and the substrate 6 and the substrate 7 are attached to the end faces of the light guide body 1. ..
Specifically, in the second embodiment, the one end surface 1f of the light guide body 1 is formed with a recess 1h that is recessed inward in the axial direction (left side in FIG. 13).

The recess 1h is hemispherical (dome-shaped) and is recessed toward the inside of the light guide body 1. Although only the end surface 1f of the light guide body 1 is shown in FIG. 13, the recess 1h is similarly formed on the other end surface 1e of the light guide body 1.
A substrate 6 is attached to the end surface 1f of the light guide body 1. The first light source 3 and the resin molded lens 31 are arranged (accommodated) in the recess 1h of the light guide body 1.

A first optical filter 55 is arranged on the inner surface of the recess 1h of the end surface 1f of the light guide body 1. Here, the arrangement means that an interference filter is formed by means such as pasting and vapor deposition. The first optical filter 55 is the same as the first optical filter 18 of the first embodiment.

The first optical filter 55 is provided with an angle conversion reflection unit 70. The surface of the angle conversion reflecting unit 70 is formed as a reflecting surface that reflects light. The angle conversion reflection unit 70 is provided on the lower side (light diffusion pattern P side) of the central axis A. The angle conversion reflection unit 70 is arranged on the main optical path E connecting one end of the light diffusion pattern P (the end on the first light source 3 side) and the first light source 3.

A light-shielding portion 56 is provided at a position facing the recess 1h on the light emitting side surface 1d of the light guide body 1. Although only one end of the light guide 1 is shown in FIG. 13, a light-shielding portion 56 is also provided at the other end of the light guide 1.

Further, although not shown, the substrate 7 is attached to the end surface 1e of the light guide body 1. Further, a filter similar to the second optical filter 19 of the first embodiment is arranged on the inner surface of the recess 1h of the end surface 1e of the light guide body 1. An angle conversion reflection unit 70 is provided on the surface of the optical filter. The angle conversion reflection unit 70 is arranged on the main light path connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the second light source 4.

When ultraviolet light is emitted from the first light source 3 in the line light source 10, the light directed to the other end of the light diffusion pattern P (the end on the first light source 3 side) of the ultraviolet light is angle-converted. Diffuse reflection or angle conversion is performed on the surface of the reflection unit 70. Of the ultraviolet light diffusely reflected or angle-converted by the angle-converted reflecting unit 70 and the ultraviolet light emitted from the first light source 3, it is upward from one end side of the light guide body 1 (light emitting side surface 1d side). The light directed toward is blocked by the light-shielding portion 56. Then, after the ultraviolet light diffusely reflected or not angle-converted by the angle-converting reflecting unit 70 or reflected by the angle-converting reflecting unit 70, the light is emitted from the recess 1h and repeatedly reflected by the light-shielding unit 56 and the cover member 2. The ultraviolet light directed into the light guide body 1 from a portion other than the angle conversion reflection unit 70 passes through the first optical filter 55 and is incident on the inside of the light guide body 1.

Further, when the line light source 10 emits visible light or light having a wavelength ranging from visible to infrared from the second light source 4, one end of the light in the light diffusion pattern P (the first light source 3 side). The light directed to the end portion) is diffusely reflected or angle-converted on the surface of the angle-converting reflection unit 70. Of the light diffusely reflected or angle-converted by the angle-converted reflecting unit 70 and the light emitted from the second light source 4, the light is directed upward (light emitting side surface 1d side) from the other end side of the light guide body 1. The light is blocked by the light-shielding portion 56. Then, the light that has not been diffusely reflected or angle-converted by the angle-converting reflecting unit 70, or the light that has not been angle-converted by the angle-converting reflecting unit 70, or is reflected by the angle-converting reflecting unit 70 and then emitted from the recess 1h to emit light from the concave portion 1h to the surface and cover of the light-shielding portion 56 on the light guide body 1 side. Light that is repeatedly reflected by the inner wall of the member 2 and heads into the light guide body 1 from a portion other than the angle conversion reflection unit 70 passes through an optical filter and is incident on the inside of the light guide body 1.

As described above, in the second embodiment, as shown in FIG. 13, the line light source 10 does not include the first tubular member 8 and the second tubular member 9, and the substrate 6 is attached to the end surface of the light guide body 1. And the board 7 is attached. A recess 1h is formed on the end surface of the light guide body 1. The angle conversion reflecting portion 70 is provided in the recess 1h. The reflective surface in the mixing space is the surface of the light-shielding portion 56 on the light guide body side 1 that encloses the recess 1h and the inner wall of the cover member 2.
From the above, it is possible to realize the miniaturization of the line light source 10.

Further, in the second embodiment, as shown in FIG. 13, the line light source 10 includes a light-shielding portion 56. The light-shielding portion 56 is provided at a position facing the recess on the light emitting side surface 1d of the light guide body 1.

Therefore, it is possible to suppress that the ultraviolet light emitted from the first light source 3 and diffusely reflected or angle-converted by the angle-converting reflecting unit 70 is directly emitted to the outside from the light emitting side surface 1d of the light guide body 1. The light-shielding portion 56 can function as a reflective surface that forms a mixing space. Similarly, visible light emitted from the second light source 4 and diffuse-reflected or angle-converted by the angle-converting reflecting unit 70, or light having a wavelength ranging from visible to infrared is emitted from the light emitting side surface 1d of the light guide body 1. It is possible to suppress direct emission to the outside. By forming at least one opening in a part of the light-shielding portion 56, or by using a semi-transparent material (optical filter) for the wavelength of the light source as the material of the light-shielding portion 56, the vicinity of the light input portion is formed. A part of the light can be taken out. The light-shielding portion 56 may be a combination of an optical filter and a diffusion material. This makes it possible to use the light-shielding portion 56 over the entire length of the light guide body 1.

Further, in the second embodiment, as shown in FIG. 13, the line light source 10 includes a first optical filter 55 provided in the recess 1h at one end. Further, although not shown, the line light source 10 includes an optical filter provided in the recess 1h at the other end. Alternatively, the recess 1h may not be provided at the other end of the light guide body 1, and the recess 1h may be combined with the tubular portions 8 and 9 of the first embodiment.

Therefore, of the light emitted from the first light source 3 and the second light source 4, only the light in a specific wavelength range can be transmitted by the optical filter and incident on the inside of the light guide body 1. Further, since the optical filter is provided in the recess 1h, the line light source 10 can be downsized. When the recesses 1h are provided at both ends of the light guide body 1, at least one opening is formed in a part of the light-shielding portion 56, or the material of the light-shielding portion 56 is semi-transmissive to the light source wavelength. By using (optical filter), a part of the light in the vicinity of the light entering portion can be taken out. The light-shielding portion 56 may be a combination of an optical filter and a diffusion material. This makes it possible to use the light-shielding portion 56 over the entire length of the light guide body 1.

<Third Embodiment>
FIG. 14 is a side sectional view of the line light source 10 according to the third embodiment of the present invention.
The shape of the recess 1i formed on the end surface of the line light source 10 of the third embodiment is different from that of the recess 1h of the line light source 10 of the second embodiment.
Specifically, in the third embodiment, the one end surface 1f of the light guide body 1 is formed with a recess 1i that is recessed inward in the central axial direction (left side in FIG. 14).

The recess 1i has a circular shape when viewed from the front, and is recessed toward the inside of the light guide body 1. Although only the end surface 1f of the light guide body 1 is shown in FIG. 14, a recess 1i is similarly formed on the other end surface 1e of the light guide body 1.

A first optical filter 57 is arranged in the recess 1i of the end surface 1f of the light guide body 1. The first optical filter 57 is provided on the end face on the inner side in the central axial direction in the recess 1i. The first optical filter 55 is the same as the first optical filter 18 of the first embodiment (the first optical filter 55 of the second embodiment). The first optical filter 57 is provided with an angle conversion reflecting unit 70. The angle conversion reflection unit 70 is arranged on the main optical path E connecting one end portion (the end portion on the first light source 3 side) of the light diffusion pattern P and the first light source 3 as in the second embodiment. ing.

Further, although not shown, the substrate 7 is attached to the end surface 1e of the light guide body 1. Further, an optical filter similar to the second optical filter 19 of the first embodiment is arranged on the inner surface of the recess 1i of the end surface 1e of the light guide body 1. An angle conversion reflecting unit 70 is provided on the surface of the optical filter as a separate body from the optical filter. Similar to the second embodiment, the angle conversion reflecting unit 70 is arranged on the main light path connecting the other end portion (the end portion on the second light source 4 side) of the light diffusion pattern P and the second light source 4. ing.

When ultraviolet light is emitted from the first light source 3 in the line light source 10, the light directed to the other end of the light diffusion pattern P (the end on the second light source 4 side) of the ultraviolet light is angle-converted. Diffuse reflection or angle conversion is performed on the surface of the reflection unit 70. Ultraviolet light that has not been diffusely reflected or angle-converted by the angle-converting reflecting unit 70, or diffused reflected or angle-converted by the angle-converting reflecting unit 70, and then repeatedly reflected by the recess 1i, and the portion other than the angle-converting reflecting unit 70. The ultraviolet light heading into the light guide body 1 passes through the first optical filter 57 and enters the inside of the light guide body 1.

Further, when the line light source 10 emits visible light or light having a wavelength ranging from visible to infrared from the second light source 4, one end of the light in the light diffusion pattern P (the first light source 3 side). The light directed to the end portion of the light is diffusely reflected or angle-converted on the surface of the angle-converting reflection unit 70. Light that has not been diffusely reflected or angle-converted by the angle-converting reflecting unit 70, or light that has been diffusely reflected or angle-converted by the angle-converting reflecting unit 70, and then repeatedly reflected by the recess 1i, from a portion other than the angle-converting reflecting unit 70. The light directed into the light guide body 1 passes through the optical filter and enters the inside of the light guide body 1.

As described above, in the third embodiment, as shown in FIG. 14, a recess 1i recessed inward in the axial direction is formed on one end surface of the light guide body 1. The recess 1i has a circular shape when viewed from the front, and is recessed toward the inside of the light guide body 1. An optical filter is arranged in the recess 1i of the end surface 1f of the light guide body 1. The optical filter is provided on the end face on the inner side in the axial direction in the recess 1i.
With such a configuration, an optical filter can be easily provided at the end of the light guide body 1.

Further, also in this case, when the recesses 1i are provided at both ends of the light guide body 1, at least one opening is formed in a part of the light-shielding portion 56, or the light source is used as the material of the light-shielding portion 56. By using a material (optical filter) that can adjust the transmittance with respect to the wavelength, it is possible to extract a part of the light in the vicinity of the light input portion. The light-shielding portion 56 may be a combination of an optical filter and a diffusion material. This makes it possible to use the light-shielding portion 56 over the entire length of the light guide body 1. As the shape of the concave portion, a combination of the concave portion 1i and the concave portion 1h of the second embodiment or a combination with another concave portion shape (not shown) can be used.
Further, as in the second embodiment, the recess 1i may not be provided at the other end of the light guide body 1, and further, the recess 1i and the tubular portions 8 and 9 of the first embodiment may be combined. There may be.

<Modification example>
In the above embodiment, the light diffusion pattern P has been described as being formed on the light guide body 1. However, the light diffusion pattern P may be configured as a separate member arranged in the vicinity of the light guide body 1.

Further, in the above embodiment, the angle conversion reflecting units 40, 60, and 70 have been described as being configured as separate members in the vicinity of the end face of the light guide body 1. However, an angle conversion reflecting portion may be formed on the end surface of the light guide body 1.

1 Light guide body 1d Light emission side surface 1e, 1f End surface 1g Light diffusion pattern forming surface 1h, 1i Recess 2 Cover member 3 First light source 4 Second light source 8 First tubular member 9 Second tubular member 10 Line light source 12 Light receiving Part 15 Ultraviolet light blocking optical filter 18, 55, 57 First optical filter 19 Second optical filter 40, 60, 70 Angle conversion Reflecting part 50, 53 Mixing space 56 Light shielding part 81, 91 Inner peripheral surface 404,605 Incident region B , C, D, E Main light path P Light diffusion pattern

Claims (15)

An optical line light source used as an illumination light source for an optical line sensor unit that reads paper sheets.
A light guide body having a long shape and having an exit surface formed along the longitudinal direction,
At least one light source that faces at least one end face in the longitudinal direction of the light guide and causes light to enter the inside of the light guide from the end face.
A light diffusion pattern provided along the longitudinal direction of the light guide body to diffuse light incident on the inside of the light guide body and emit it from the emission surface.
It is provided on the main light path connecting the end of the light diffusion pattern on the light source side and the light source, and has an angle conversion function of converting the angle of a part of the light incident on the inside of the light guide from the light source. Angle conversion reflector and
A mixing space formed by a reflecting surface that reflects the angle-converted light by the angle-converting reflecting unit, and for guiding the light reflected by the reflecting surface to the inside of the light guide together with the light from the light source.
It is provided with a tubular member arranged so as to face the end face of the light guide and having the mixing space formed inside.
The angle conversion reflecting portion includes an annular portion and a shielding portion arranged inside the annular portion, and the shielding portion is located on the light source side in the light diffusion pattern at a position separated from the annular portion. It is provided on the main light path connecting the end and the light source.
The mixing space is formed so that the cross-sectional area becomes at least equal to or larger than the area of the end portion on the light source side as the distance from the light source increases.
Of the light angle-converted by the angle-converting reflector, the light returning to the light source side reciprocates between the angle-converting reflector and the light source at least once in the mixing space, and the angle-converting reflection occurs. The unit is a line light source characterized in that the unit is arranged so as to block the light on the main light path with respect to the light diffusion pattern. The line light source according to claim 1, wherein the angle conversion reflecting unit has a diffuse reflection, a mirror surface reflection, or an angle conversion function by reflection including diffuse reflection and specular reflection. The line light source according to claim 1 or 2, wherein the mixing space is formed so as to be arranged so as to face the end surface of the light guide body. A recess for accommodating the light source is formed on the end face of the light guide.
The line light source according to any one of claims 1 to 3, wherein the angle conversion reflecting unit is provided in the recess. The line light source according to claim 4, further comprising a light-shielding portion provided at a position facing the concave portion on the emission surface of the light guide body. The line light source according to claim 5, wherein the light-shielding portion is an optical filter having an arbitrary transmittance with respect to the wavelength of the light source, or is made of a combination of the optical filter and a diffusion material. The line light source according to claim 5 or 6, wherein the light-shielding portion is formed with at least one arbitrary opening. When the area of the incident region where the light from the light source is incident on the end face of the light guide is D, and the projected area of the angle conversion reflecting portion on the end face of the light guide is S, 8 <( The line light source according to any one of claims 1 to 7, wherein the relational expression of D + S) / S <12 is satisfied. Claim 1 is characterized in that the surface of the angle conversion reflecting portion has a diffuse reflection function composed of a curved surface or a combination of different types of curved surfaces, a specular reflection function, or an angle conversion function by reflection including diffuse reflection and specular reflection. The line light source according to any one of 8 to 8. The claim is characterized in that the surface of the angle conversion reflecting portion has a diffuse reflection function composed of a plane or a combination of planes having different angles, a specular reflection function, or an angle conversion function by reflection including diffuse reflection and specular reflection. The line light source according to any one of 1 to 8. The method 1 to 8 is characterized in that the surface of the angle conversion reflecting portion has a diffuse reflection function composed of a combination of a flat surface and a curved surface, a mirror surface reflection function, or an angle conversion function by reflection including diffuse reflection and mirror surface reflection. The line light source according to any one item. The at least one light source is
A first light source that faces one end face in the longitudinal direction of the light guide and causes ultraviolet light to enter the inside of the light guide from the one end face.
A second light source facing the other end face in the longitudinal direction of the light guide and incident light in a wavelength range including visible light or visible light to infrared light into the inside of the light guide from the other end face. The line light source according to any one of claims 1 to 11, wherein the line light source includes a light source. First optics arranged between one end face of the light guide and the first light source to transmit ultraviolet light and block visible light or light in a wavelength range including visible light to infrared light. With more filters
The line light source according to claim 12, wherein the angle conversion reflection unit is provided on a main light path connecting an end portion of the light diffusion pattern on the first light source side and the first light source. Second optics arranged between the other end face of the light guide and the second light source to transmit visible light or light in a wavelength range including visible light to infrared light and block ultraviolet light. With more filters
The line according to claim 12 or 13, wherein the angle conversion reflection unit is provided on a main light path connecting an end portion of the light diffusion pattern on the second light source side and the second light source. light source. The line light source according to any one of claims 1 to 14,
A lens array for guiding light emitted from the line light source and reflected or transmitted by the paper sheets.
A light receiving unit that receives light converged by the lens array and converts it into an electric signal.
Extraviolet light is provided between the paper sheets and the light receiving portion to transmit visible light or light in a wavelength range including visible light to infrared light so that ultraviolet light does not enter the light receiving portion. An optical line sensor unit including a third optical filter that blocks light.

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