JPS63271330A - Slit illuminating device - Google Patents

Abstract

PURPOSE:To miniaturize a device and to improve lighting efficiency by arranging a convergent optical element between a light source and an object to be irradiated. CONSTITUTION:The titled device is provided with the linear or band-like light source and the non-imaging convergent optical element arranged between the light source and an object to be irradiated to lead light beams from the light source to the object. For instance, most of light beams obtained from an aperture 8 of an aperture type fluorescent lamp 6 is made incident upon the convergent optical element 11 (obtained by forming a transparent refractive material cylindrically). The incident light generates stagmatic refraction (the geometrical optical refraction of each incident light beam upon the incident face) by the element 11. The refraction displays a convergent effect also for light beams other than an ideal optical path in the geometric optical image formation system. Consequently, the device can be miniaturized and light beams from the light source can be efficiently led onto an object to be irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an illumination device for a projection optical system that performs slit exposure in an electronic copying machine or the like.

Conventional technology Conventionally, slit lighting devices used in electronic copying machines, etc. generally use a linear light source such as a halogen bulb or a strip light source such as an aperture-type fluorescent lamp, and a reflecting mirror or cylindrical lens (imaging lens). (For example, Japanese Patent Laid-Open No. 100430/1983).

The slit illumination device disclosed in Japanese Patent Application Laid-Open No. 59-100430 is an example of a combination of a halogen bulb, which is a linear light source, and a reflecting mirror, and is realized as a device as shown in FIG. 4.

In this device, a light beam from a halogen bulb 1 is focused onto the surface of the document using reflecting mirrors 2 and 3 to illuminate the document 4.

Further, FIG. 5 shows an example in which an aperture-type fluorescent lamp, which is a band-shaped light source, is combined with a cylindrical lens. In this device, a light beam from an aperture-type fluorescent lamp 6 is focused onto the document surface by a cylindrical lens 7 to illuminate the document 4.

Further, FIG. 6 shows an example of a slit illumination device composed only of aperture-type fluorescent lamps. In this illumination device, the document 4 is directly illuminated by the aperture-type tendency lamp 6.

Problems to be Solved by the Invention However, in the slit lighting device like the first conventional example,
In order to increase lighting efficiency, the reflecting mirror becomes larger relative to the size of the light source, and the entire device becomes larger. Further, the slit illumination device as in the second conventional example has problems in that the device becomes large in size and the amount of light incident on the cylindrical lens 7 is small, resulting in poor efficiency. This is due to the following reasons.

Usually, in a slit lighting device such as the first conventional example, the shape of the reflecting mirror 2 is a part of an ellipse, and the halogen bulb 1 is arranged at an elliptical focal point to condense the luminous flux of the halogen bulb 1 to the other elliptical focal point. It's shining. Here, in order to efficiently collect the luminous flux of the halogen bulb 1, the angle δ extending from the elliptical focal point where the halogen bulb 1 is placed to the reflecting mirror 2 is set to be large, so the major axis of the ellipse is larger than the minor axis. Therefore, the distance from the halogen bulb 1 to the irradiation surface increases. For this reason, the reflecting mirror 2 is larger than the halogen bulb 1, making the entire device larger. Further, in the slit illumination device such as the second conventional example, the cylindrical lens 7 projects the aperture 8 of the aperture-type fluorescent lamp 6, which is a band-shaped light source, onto the document surface that is the irradiation target.

Therefore, the distance from the aperture 8 of the aperture-type fluorescent lamp 6 to the document surface is calculated from the image formation formula by the cylindrical lens 7.
The length is required to be four times the focal length f. For this reason, the device becomes larger and the cylindrical lens 7 cannot be placed close to the aperture-type fluorescent lamp 6.

Furthermore, with the slit illumination devices such as the first and second conventional examples, it is not possible to efficiently collect the luminous flux from the light source onto a narrow irradiation surface, so it is necessary to widen the slit width or increase the F number of the projection lens. , a sufficient amount of exposure was obtained by reducing the scanning speed. As a result, the depth of focus of the projection lens cannot be sufficiently increased, and the diameter of the photosensitive drum cannot be reduced (that is, the copying machine becomes larger). Further, in a reading device constructed from a line scanning element such as a CCD or a photodiode array and a slit illumination device, the slit width cannot be increased, so there is a problem that the reading speed cannot be increased. This is due to the following reason.

In light sources such as the halogen light bulb 1 and the aperture-type fluorescent lamp 6 shown in the first and second conventional examples, since the light source has a large size (because it is a surface light source), the light beam diffused from the light source is used for narrow irradiation. It cannot be collected efficiently on a surface.

Therefore, an object of the first invention is to provide a slit illumination device that is small and has high illumination efficiency.

In addition, in the slit illumination device as shown in the third conventional example, the maximum illumination portion on the document surface obtained by the aperture-type fluorescent lamp 6 is in the shadow of the aperture-type fluorescent lamp 6 when viewed from the reading section 1. There is a problem in that the luminous flux of the shaped fluorescent lamp 6 cannot be fully utilized. This is due to the following reasons.

That is, in this lighting device, the luminous flux from the aperture-type fluorescent lamp 6 is emitted from the opening 8. This luminous flux spreads as shown in FIG. Here, the length of the arrow represents the intensity (luminous intensity) of the light. However, the irradiation surface 5
The illuminance at A near the aperture 8 is proportional to the luminous intensity, inversely proportional to the square of the distance, and inversely proportional to the cosine of the angle of incidence.
The luminous intensity for point B is smaller than that for point B (approximately 17
2) However, since the distance from the aperture 8 at point A is shorter (approximately 172) and the angle of incidence is also smaller, the illuminance at point A is higher. Therefore, the maximum illuminance portion on the document surface is in the shadow of the aperture-type fluorescent lamp 6 and the reading section 1
I can't see it from 0.

Therefore, it is an object of the second invention to provide a slit illumination device that can efficiently guide the luminous flux of an aperture-type fluorescent lamp to an irradiation target.

Means for Solving the Problems The first invention solves the above first problem by disposing a light source in the form of a cotton or strip and between this light source and an irradiation surface, and using a light beam from this light source. It is equipped with a non-imaging focusing optical element that guides the irradiation target to the irradiation target.

In addition, the second invention solves the above second problem,
It consists of an aperture-type fluorescent lamp and a transparent refractive material formed into a columnar shape with a circular or elliptical cross-section. The irradiation angle with respect to the irradiation target was set to 3 to prevent the aperture-type fluorescent lamp from being placed between
The angle is set from 0° to 50°.

The first invention uses the above-described configuration to collect a part of the light beam emitted in all directions from a linear or band-shaped light source using a non-imaging focusing optical element and efficiently guide it to the irradiation target. .

The second invention uses the above-described configuration to focus the light beam from the aperture-type fluorescent lamp using a transparent refractive material and irradiate the irradiation target from an oblique direction, thereby effectively utilizing the maximum illuminance portion on the irradiation surface. be.

Embodiment FIG. 1 is a block diagram showing a first embodiment of a slit illumination device, which corresponds to the first invention. In the figure, 4 is a document, 5 is an irradiation surface, 6 is an aperture type fluorescent lamp, 8 is an aperture of the aperture type fluorescent lamp 6, 9 is a contact glass, and 11 is a focusing optical element. The optical element 11 is formed of a transparent refractive material into a cylindrical shape.

The operation of the slit illumination device of the first embodiment configured as described above will be described below.

The luminous flux from the aperture-type fluorescent lamp 6 is emitted from the opening 8 . This light flux spreads radially. Therefore, the radially spreading light beam is focused by a focusing optical element 11 provided parallel to the aperture-type fluorescent lamp 6 and guided to the irradiation surface 5.

Here, the light focusing state of the focusing optical element 11 formed of a transparent refractive material into a cylindrical shape will be described in more detail. However, since the contact glass 9 only has the effect of changing the angle of incidence by refraction and shortening the optical bus, the contact glass 9 is omitted here to make the explanation easier to understand. This will be explained using FIG. For the sake of explanation, FIG. 8 shows only the parallel light component of the light from the aperture 8 of the aperture-type fluorescent lamp 6, and FIG. 9 shows the aperture 8 of the aperture-type fluorescent lamp 6.
The figure shows the light coming from two points of the aperture 8 among the light coming from the aperture 8. Furthermore, light from other points of the aperture 8 and light in other directions are similarly condensed.

Most of the light from the aperture 8 of the aperture-type fluorescent lamp 6 is incident on the focusing optical element 11 (a transparent refractive material formed into a cylindrical shape). This is because the focusing optical element 11 (made of transparent refractive material formed into a cylindrical shape) is placed close to the aperture 8 of the aperture-type fluorescent lamp 6. This is because the angle at which the transparent refractive material is formed into a cylindrical shape becomes large. The incident light undergoes stigmatic refraction (each incident ray is refracted geometrically with respect to the incident surface) by the focusing optical element 11 (a transparent refractive material formed into a cylindrical shape). It also has a focusing effect on light fluxes other than the ideal optical path in a geometrical optical imaging system, and has a large focusing effect on light sources (diffuse light sources, surface light sources) that have a large amount of light flux other than the ideal optical path in the imaging system. effective.

Furthermore, as shown in FIG.
(a transparent refractive material formed into a cylindrical shape).

The incident light undergoes stigmatic refraction (geometrical optical refraction of each incident light ray with respect to the incident surface) by the focusing optical element 11 (a transparent refractive material formed into a cylindrical shape).

Due to this stigmatic refraction, the light is focused but not at one point, and as is clear from FIG. 9, the (density of) the luminous flux is approximately uniform between point A and point B.

Therefore, the slit illumination device of this embodiment can solve the following problem that was a problem with the conventional slit illumination device. In other words, when copying a thick original 4 (three-dimensional object), the degree of light gathering differs greatly depending on the surface that contacts the contact glass 9 and the surface that does not, so the illumination level The problem is that since it is not possible to make the image uniform, shadows appear on the reproduced image.

Therefore, the effect of condensing light in the scanning direction (cross-sectional direction of the aperture-type fluorescent lamp [band-shaped light source]) as shown in Fig. 10 can be obtained over a wide range from point A to point B shown in Fig. 9. , the luminous flux from the aperture 8 of the aperture-type fluorescent lamp 6 can be efficiently focused on the narrow irradiation surface 5, and the irradiation surface 5 can be placed between the point A and the point B so that the thick original 4 (three-dimensional object) can be efficiently collected. ), the irradiation surface 5
Since the illuminance above is uniform, the original 4 can be illuminated uniformly.

Also, at this time, since the curvature of the focusing optical element 11 (made of a transparent refractive material formed into a cylindrical shape) is larger than that of a normal lens, the light passes through the focusing optical element 11 compared to a normal lens.
(a transparent refractive material formed into a cylindrical shape). The part where this light is focused is the irradiation surface 5
By doing so, the original 4 is efficiently illuminated.

As described above, according to the first embodiment, the aperture-type fluorescent lamp and the focusing optical element formed of a transparent refractive material into a column with a circular or elliptical cross-sectional shape are provided in parallel, thereby achieving a simple structure. It is possible to realize a slit illumination device with high illumination efficiency, and also to provide a slit illumination device that can provide uniform illumination when copying a thick original (three-dimensional object).

FIG. 2 is a block diagram showing a second embodiment of the slit opening device of the present application, which corresponds to the first invention.

In the figure, 1 is a halogen light bulb, 4 is a Wt screen, 5 is an irradiation surface, 9 is a contact glass, and 12 is a focusing optical element. It uses a transparent flat plate with a distributed refractive index.

The operation of the slit illumination device of the second embodiment configured as described above will be described below.

The light flux from the halogen bulb 1 spreads from the filament of the halogen bulb 1 to the radiation sample. Therefore, a focusing optical element 12 provided parallel to the halogen bulb 1 focuses the light beam spreading across the radiation sample and guides it to the irradiation surface 5.

Here, the focusing state of the focusing optical element 12, which is a transparent flat plate having a distributed refractive index, will be explained in more detail. However, since the contact glass 9 only has the effect of changing the irradiation angle by refraction and shortening the optical path, the contact glass 9 is omitted here to make the explanation easier to understand, and FIG. 11 is used instead. I will explain.

In FIG. 11(A), most of the light from the halogen bulb 1 is incident on the focusing optical element 12 (a transparent flat plate with a distributed refractive index). This is because the focusing optical element 12 (a transparent flat plate with a distributed refractive index) is placed close to the halogen bulb 1, so the angle from the halogen bulb 1 to the focusing optical element 12 (a transparent flat plate with a distributed refractive index) is large. To become. Focusing optical element 12 (transparent flat plate with distributed refractive index)
The incident light continuously bends its optical path in the focusing optical element 12 (a transparent flat plate with a distributed refractive index). That is,
It is thought that refraction occurs continuously.

This continuous refraction, as shown in FIG. The closer the object is to the edge of the transparent flat plate), the higher the refractive index, so it receives stronger refractive power and is refracted at a smaller refraction angle than the incident angle. In addition, since the refractive index of the focusing optical element 12 (a transparent flat plate with a distributed refractive index) increases in the thickness direction, the light from the halogen bulb 1 receives even greater refractive power as it travels, and is continuously causes a certain refraction. In this way, as shown in FIG. 11(A), the light from the halogen bulb 1 can be focused. Also, light is focused on one point, or light is not focused on one point,
The focusing optical element 12 (transparent flat plate having a distributed refractive index) having the above characteristics can be easily determined by setting the distributed refractive index.

Furthermore, the refraction of the focusing optical element 12 (a transparent flat plate with a distributed refractive index) has a focusing effect on light beams other than the ideal optical path in the geometric optical imaging system, and It also has a great focusing effect on light sources with a large luminous flux (diffuse light sources, surface light sources) other than the optical path.

This is because in normal geometric optics refraction, the optical path changes due to refraction at the entrance and exit surfaces of the imaging element (lens), so the refraction angle changes greatly depending on the incident angle to the entrance and exit surfaces. A focusing effect cannot be expected for light beams other than ideal optical paths. On the other hand, in the focusing optical element 12 (a transparent flat plate with a distributed refractive index), refraction occurs not only on the surface of the focusing optical element 12 (a transparent flat plate with a distributed refractive index), but also inside the focusing optical element 12 (a transparent flat plate with a distributed refractive index). The effect is less affected by the angle of incidence, and a focusing effect can be obtained even for light beams incident from non-ideal optical paths.

Therefore, as in the first embodiment, the light condensing effect as shown in FIG. 10 can be obtained, so that the luminous flux from the halogen bulb 1 can be efficiently condensed onto the narrow irradiation surface 5.

As described above, according to the second embodiment, a slit illumination device with a simple structure and high illumination efficiency can be realized by providing a halogen bulb and a transparent flat plate focusing optical element having a distributed refractive index in parallel.

FIG. 3 is a block diagram showing a third embodiment of the slit illumination device, which corresponds to the second invention.

In the figure, 10 is a reading unit, 4 is a document, 5 is an irradiation surface,
6 is an aperture type fluorescent lamp, 8 is an opening of the aperture type fluorescent lamp, 9 is a contact glass, 13 is a transparent refractive material formed in a column shape; It is something.

The operation of the slit illumination device of the third embodiment configured as described above will be described below.

The luminous flux from the aperture-type fluorescent lamp 6 is emitted from the opening 8 . This light flux spreads radially. Therefore, the light beam spreading from the aperture 8 as diffused light is focused and guided to the irradiation surface 5 by the transparent refractive material 13 formed in a columnar shape.

Here, the optical function of the columnar transparent refractive material 'R13 will be explained in more detail with reference to FIG. 12.

Most of the light from the aperture 8 of the aperture-type fluorescent lamp 6 enters the transparent refractive material 1f413. This is because the transparent refractive material pH3 is disposed close to the opening 8 of the aperture-type fluorescent lamp 6, so that the angle extending from the opening 8 of the aperture-type fluorescent lamp 6 to the transparent refractive material 13 becomes large. The incident light undergoes stigmatic refraction by the transparent refractive material N13. The light is focused by this stigmatic refraction and illuminates the irradiation surface 5. At this time, the illumination light that is focused by the transparent refractive material 13 and illuminates the irradiation surface 5 is refracted by the contact glass 9 and illuminates the irradiation surface 5 at an incident angle φ smaller than the irradiation angle θ. Here, the smaller the incident angle φ is, the greater the illumination intensity on the irradiation surface 5 is, and the better the illumination efficiency is. Therefore, the illumination efficiency becomes better as the illumination angle θ becomes smaller, but as the illumination angle θ becomes smaller, below a certain angle, the maximum illuminance portion illuminated by this slit illumination device becomes Aperture type fluorescent lamp 6 or transparent refractive material 1'413
becomes the shadow of Furthermore, when the incident angle φ becomes extremely small, the specularly reflected light from the irradiation surface 5Wi of the contact glass 9 is reflected by the reading unit 1.
0 and causes white spots in the copied image.

Here, this will be quantitatively explained using FIG. 13. FIG. 13 is a diagram schematically showing the positional relationship between the transparent refractive material 13 and the irradiation surface 5. In FIG. 13(A), since the maximum illuminance portion is not in the shadow of the transparent refractive material 13 when viewed from the reading section 10, it is provided at a distance C corresponding to the size of the transparent refractive material 13 from the optical axis. At this time, the relationship between the distance from the transparent refractive material 13 to the irradiation surface 5 and the irradiation angle θ can be expressed by the following equation.

L sin θ=C (1) On the other hand, in FIG. 13(B), the transparent refractive material 13 is provided at a distance C corresponding to the size of the original from the original because the transparent refractive material 13 does not touch the original. Transparent refractive material 13 at this time
The relationship between the distance from to the irradiation surface 5 and the irradiation angle θ can be expressed by the following equation.

L cos θ=C(2) The relationship between the base and θ expressed by equations (1) and (2) is shown as a graph in FIG. The distance 11L to the irradiation surface 5 in the third embodiment can be expressed by the larger of the equations (1) and (2). Therefore, L becomes minimum when the illumination angle θ becomes 45'. here,
Consider the illuminance of the irradiation surface 5. Illuminance is generally determined by the illumination angle θ
is proportional to the cosine of and inversely proportional to the square of the distance. Here, since the light is focused by the transparent refractive material 13, the illumination intensity is not inversely proportional to the square of the distance, but is usually inversely proportional to the distance. The relationship between the illuminance and the irradiation angle θ at this time is as shown in FIG. Therefore, the irradiation angle that maximizes the illuminance is approximately 45°, and if the irradiation angle is set in the range of 30° to 50°, 80% of the aforementioned maximum illuminance can be secured, making it suitable for use as a slit lighting device. It is at a sufficient level.

Next, the relationship between the diameter of the transparent refractive material 13 having a circular cross-sectional shape, the width of the opening 8 of the aperture-type fluorescent lamp 6, and the illuminance on the irradiation surface 5 will be explained.

FIG. 16 shows a transparent refractive material 13 with an irradiation angle of 45° and a circular cross-sectional shape in the aperture 8 of the aperture-type fluorescent lamp 6.
This figure shows the relationship between the diameter of the transparent refractive material 13 and the maximum illuminance on the irradiation surface 5 (the maximum illuminance obtained by changing the position of the aperture-type fluorescent lamp 6) when the transparent refractive material 13 is installed in close contact with the transparent refractive material 13. Further, FIG. 17 shows the width of the aperture 8 of the aperture-type fluorescent lamp 6 when the irradiation angle is 45° and the transparent refractive material 13 having a circular cross-section is placed in close contact with the aperture 8 of the aperture-type fluorescent lamp 6. This figure shows the relationship between and the maximum illuminance on the irradiation surface 5 (the maximum illuminance obtained by changing the position of the aperture-type fluorescent lamp 6).

Note that the reason why the transparent refractive material 13 is placed in close contact with the aperture 8 of the aperture type fluorescent lamp 6 is to allow the light beam from the aperture 8 of the aperture type fluorescent lamp 6 to enter the transparent refractive material 13 without waste. Even if a horizontal spacing is provided between the aperture 8 of the aperture-type fluorescent lamp 6 and the transparent refractive material 13 in design, the effect is not affected.

It is clear from FIGS. 16 and 17 that the maximum illuminance on the irradiation surface 5 is maximized when the width (W) of the aperture 8 of the aperture-type fluorescent lamp 6 is about 3, and This is when the diameter (Dl) of the material 13 is from 9 to 12. Therefore, this is when the ratio (W/D 1) between the width (W) of the opening 8 of the aperture-type fluorescent lamp 6 and the diameter (Dl) of the transparent refractive material 13 is 1/3 to 1/4. It is best to set this condition.

In addition, the width of the opening 8 of the aperture-type fluorescent lamp 6 (
The relationship between W), the diameter (D2) of the aperture-type fluorescent lamp 6, and the illuminance on the irradiation surface 5 will be explained.

FIG. 18 shows the above-mentioned conditions [irradiation angle 45°, ratio (W/Di) of the width (W) of the opening 8 of the aperture type fluorescent lamp 6 to the diameter (Dl) of the transparent refractive material 13 is 1/3. 1/4 from
] and the width of the opening 8 of the aperture-type fluorescent lamp 6 (
The maximum illuminance on the irradiation surface 5 when changing the ratio (W/D2) between W) and the diameter (D2) of the aperture-type fluorescent lamp 6 (maximum illuminance obtained by changing the position of the aperture-type fluorescent lamp 6). This is what is shown. Note that the larger the diameter (D2) of the aperture-type fluorescent lamp 6, the larger the tube current of the aperture-type fluorescent lamp 6, which increases the luminous flux. be.

It is clear from the figure that the opening 8 of the aperture type fluorescent lamp 6
width (W) and diameter (D2) of the aperture-type fluorescent lamp 6
The maximum illuminance on the irradiation surface 5 becomes maximum when the ratio (W/D 2 ) of
Even if /D2) is set from 1/4 to 1/6, 95% of the above-mentioned maximum illuminance can be secured, which is sufficient for practical use.

As described above, according to the third embodiment, the luminous flux from the aperture-type fluorescent lamp is focused on the irradiation surface by the transparent refractive material, so that the irradiation range on the irradiation surface is narrowed, and the maximum illuminance is Since the area can be used, highly efficient lighting can be realized.

In addition, by placing an aperture-type fluorescent lamp and a transparent refractive material formed in a column with a circular cross-section in parallel, it is possible to focus the light without concentrating it on a single point on the irradiation surface. A slit illumination device that can provide uniform illumination even when copying a certain original (three-dimensional object) can be realized.

In the first embodiment, a transparent refractive material formed into a cylindrical shape (circular in cross-section) was used as the focusing optical element, but other cross-sectional shapes, such as an ellipse, can also be used to focus light. It is fine as long as it has a shape that allows

Further, in the first embodiment, an aperture-type fluorescent lamp with a band-shaped light source is used as the light source, and in the second embodiment,
Although a halogen light bulb with a linear light source was used as the light source, the same effect can be obtained by using a linear light source or a band-shaped light source.

In the third embodiment, the case where the cross-sectional shape is circular has been explained, but even if the cross-sectional shape is oval, its optical characteristics (
For the same reason, the operation) is similar to that of a circular shape, and the irradiation angle is optimally set from 30° to 50°.

Effects of the Invention The slit illumination device of the present invention is compact and can efficiently target the luminous flux from the light source by providing a non-imaging focusing optical element between the linear or strip light source and the irradiation target. It is possible to provide a slit lighting device that can be guided, and its practical effects are great.

Furthermore, the slit illumination device of the present invention includes an aperture-type fluorescent lamp and a transparent refractive material formed into a pillar having a circular or elliptical cross-sectional shape, which are arranged in parallel, and the irradiation angle with respect to the irradiation target is changed from 30° to 50°. I set it.

As a result, it is possible to provide a slit illumination device that can efficiently guide the luminous flux from an aperture-type fluorescent lamp to an irradiation target, and its practical effects are great.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of a slit illumination device in a first embodiment of the present invention, Fig. 2 is a principle diagram of a slit illumination device in a second embodiment of the present invention, and Fig. 3 is a principle diagram of a slit illumination device in a second embodiment of the present invention. A diagram of the principle of a slit illumination device in an example. Fig. 4 is a diagram of the principle of a slit illumination device that combines a halogen bulb, which is a conventional linear light source, and a reflecting mirror. Fig. 5 is a diagram of the principle of a slit illumination device, which is a combination of a halogen bulb, which is a conventional linear light source, and a reflecting mirror. Figure 6 shows the principle of a slit lighting device that combines a lamp and a cylindrical lens. Figure 6 shows the principle of a slit lighting device that uses only conventional aperture-type fluorescent lamps. Figure 7 shows the problems with the conventional slit lighting device. 8 and 9 are principle diagrams showing the function of a focusing optical element (transparent refractive material formed into a cylindrical shape), and FIG. 10 is a slit illumination device of the first and second embodiments. A characteristic diagram showing a comparison between the illuminance distribution on the irradiated surface obtained by the method and the illuminance distribution on the irradiated surface obtained by the conventional slit illumination device. FIG. 12 is a principle diagram showing the optical function of the transparent refractive material of the third embodiment. FIG. 13 is a diagram showing the relationship between the irradiation angle θ and the distance to the irradiation surface 5. , FIG. 14 is a characteristic diagram showing the relationship between the irradiation angle θ and the distance to the irradiation surface 5, FIG. 15 is a characteristic diagram showing the relationship between the irradiation angle θ and the illuminance on the irradiation surface S, and FIG. 16 17 is a characteristic diagram showing the relationship between the diameter of the transparent refractive material 13 having a circular cross-sectional shape and the maximum illuminance on the irradiation surface 5, and FIG. FIG. 18 is a characteristic diagram showing the relationship between the ratio of the width of the aperture 80 of the aperture-type fluorescent lamp 6 to the diameter of the aperture-type fluorescent lamp 6 and the maximum illuminance on the irradiation surface 5. be. 1...Halogen light bulb, 4...Manuscript, 5...
・Irradiation surface, 6...Aperture type fluorescent lamp, 8...
. . . Opening of aperture-type fluorescent lamp 6, 10 . . . Transparent flat plate with distributed refractive index), 13...Transparent refractive material Name of agent: Patent attorney Toshio Nakao (1 person) Figure 4 Figure 5 Figure 67 No-4-V type fluorescent lamp Figure 6 Figure 7 8 [A 310 Figure Conventional Example A 4P+ Scanning 7 Open Position Figure 11 (A) LB) Figure 13<A) CB) 14 Figure 4! II Skin angle θ jI16: I! Diameter D1 of IFiFI refractive material 13 (Kanshin! Gobununa gl)
Figure 8

Claims (7)

[Claims] (1) A slit illumination device comprising a linear or band-shaped light source and a non-imaging focusing optical element, the focusing optical element being provided between the light source and an irradiation target. (2) An aperture-type fluorescent lamp is used as a strip-shaped light source, and a transparent refractive material formed in a columnar shape is used as a non-imaging focusing optical element, and the transparent refractive material is provided parallel to the aperture-type fluorescent lamp. Claim 1
The slit illumination device described in Section 1. (3) The slit illumination device according to claim 2, wherein the cross-sectional shape of the transparent refractive material is circular or elliptical. (4) Consisting of an aperture-shaped fluorescent lamp and a transparent refractive material formed into a columnar shape, the transparent refractive material is provided in parallel to the aperture-shaped fluorescent lamp, and the irradiation from the aperture-shaped fluorescent lamp is transmitted through the transparent refractive material. The beam angle is 3
The slit illumination device according to claim 2, characterized in that the angle is from 0° to 50°. (5) The slit illumination device according to claim 4, wherein the transparent refractive material has a circular or elliptical cross-sectional shape. (6) The cross-sectional shape of the transparent refractive material is circular, and the width of the opening of the aperture-type fluorescent lamp is 1/3 to 1/4 of the diameter of the transparent refractive material. The slit illumination device described in Section 1. (7) The slit lighting device according to claim 6, wherein the width of the opening of the aperture-type fluorescent lamp is set to 1/4 to 1/6 of the diameter of the aperture-type fluorescent lamp.