JP2000304760A - Long sheet light generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently irradiate in a sheet-like state only a necessary region by disposing a longitudinally long slit and a cylindrical lens between a light source and an irradiating region, suitably selecting the width of the slit and sliding a disposing position of the lens. SOLUTION: A cylindrical lens 3 having a predetermined focal distance and shape is disposed between a light source 1 such as a fluorescent lamp having a predetermined size and an irradiating surface, a longitudinally long slit 6 for throttling an irradiation light is disposed between the lens 3 and the source 1, and a reflecting plate 2 is disposed the rear of the source 1. Since a light amount distribution is different on the irradiating surface according to the focal distance of the lens 3, the interval of the slit 6 and the distance between the slit 6 and the irradiating region, the distance between the lens 3 and the source 2 or the width of the slit 5 is suitably selected, and the region is irradiated with a light near the parallel sheet light. In this case, the irradiating light is not dispersed, reflected lights of a leakage tracer or a space float are reduced to suppress a noise, and only necessary region can be efficiently irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a long sheet light generating device used for a long light source of an air flow visualizing device.

[0002]

2. Description of the Related Art A tracer (water vapor, etc.) is jetted into a space, and it is observed that the tracer moves with an air flow.
A method of visualizing the flow of the air flow in the space is known (for example, JP-A-5-33303), and the inventor of the present application ejects water vapor as a tracer into a predetermined space to check the falling state. Reflected by the light source provided on the side,
A device that captures this with a video camera and visualizes it on a screen has been proposed (Japanese Patent Application No. 10-187259).

FIG. 12 is a diagram showing a basic schematic structure of an air flow visualization device. In FIG. 12, reference numeral 101 denotes a device which is horizontally disposed at a predetermined height with respect to an installation floor surface and ejects the steam tracer. A tracer ejection pipe, in which a plurality of tracer ejection holes of a steam tracer are arranged at predetermined intervals, and when a steam tracer generated in the tracer generation unit 104 is blown in from one end, the steam tracer emits the plurality of tracer ejections. It is ejected from the hole and ejected with a predetermined thickness and width in a predetermined space which is a measurement area.

In order to irradiate the sprayed water vapor tracer with light from the side, an illuminating lamp, which is a long light source with a reflector 105, is perpendicular to the tracer pipe 101. Are arranged in a direction to irradiate the lower side of the hologram. In FIG. 12, 103 is a movable cover for gently ejecting the steam tracer blown out from the ejection hole, and 102 is a liquefied water droplet when the steam tracer in the ejection pipe 101 is liquefied. A water droplet receiving unit 106 for receiving and preventing the floor surface from getting wet is a video camera for photographing the moving state of the jetted water vapor tracer.

FIG. 13 is a detailed configuration diagram of the long light source 105 with a reflector used in the conventional air flow visualization device and the like. In FIG. 13, a long light source 105 with a reflecting plate includes an illuminating lamp 105 a serving as a light source, a power supply 105 b for supplying power to the illuminating lamp 105 a, a reflecting plate 105 c for condensing light from the illuminating lamp 105 a, and a filter 105 d. It is configured.

[0006] Specifically, the long light source 105 with the reflection plate is used.
Is an illumination lamp 105 having a length of 677 mm and a power consumption of 20 W.
As a, a special illumination lamp (fluorescent lamp) manufactured by Matsushita Electric Works Co., Ltd. (product number: EA41520P), which does not flicker, is used. A transparent red film 105d is attached to the light emitting surface of the illuminating lamp 105a to provide a light source having a wavelength close to a single wavelength. The reflecting plate 105c provided on the long light source 105 with a reflecting plate has a parabolic column surface having an opening on the measurement region side, and the inside thereof serves as a light reflecting surface to efficiently transmit light from the illumination lamp 105a. It has a structure in which light is condensed well and illuminated at a predetermined width in the direction of the measurement region via the filter 105d.

[0007]

However, since the fluorescent lamp long light source 105 is not a perfect point light source (line light source), even if the reflecting plate 105c is provided, light emitted from the reflecting plate 105c does not reach a predetermined point. Irradiating only the width of the sheet in a sheet shape, that is, a so-called sheet light cannot be obtained. That is, the emission light of the long light source 105 described above is provided with the reflection plate 105c to narrow the emission light in the irradiation direction. However, the narrowing is not perfect, and the light source is a fluorescent lamp or the like. Because it is not a perfect point light source, it is difficult to generate a parallel light with a narrow irradiation area that irradiates only the irradiation area, and therefore, irradiates an unnecessary area to the irradiation area. Had a loss of irradiation. In addition, since the light is not parallel light, it is difficult to perform high-resolution visualization in which an area in a direction perpendicular to the cross section of the visualization area (a depth direction viewed from the imaging direction) is limited.

[0008] Further, since the area other than the required area is irradiated, the water vapor mist tracer and the suspended matter in the area are also irradiated, and the vapor mist tracer and the suspended substance other than the necessary area are irradiated. Is reflected on the measurement area, which has an adverse effect on the measurement area as so-called noise. Therefore,
The present inventor has repeatedly devised a sheet light generation that irradiates only a necessary area in a sheet shape while using a fluorescent lamp in order to solve the above-described conventional problems, and the present invention It is another object of the present invention to provide a sheet light generating device that efficiently irradiates only a necessary area in a sheet shape. Another object of the present invention is to provide a sheet light generation device in which a plurality of light-emitting LEDs are arranged in a row or a plurality of rows instead of a fluorescent lamp, and light emission from the LEDs is controlled to irradiate only a necessary area in a sheet shape. Is what you do.

[0009]

According to a first aspect of the present invention, in a long sheet light generating apparatus, a vertically elongated slit for narrowing irradiation light between a light source and an irradiation area, and a cylindrical having a predetermined focal length. A lens is provided, and the slit width of the longitudinal slit and the arrangement position of the cylindrical lens are configured to be slidable.

[0010]

FIG. 1 is a basic configuration diagram showing one embodiment of a sheet light generating unit according to the present invention. The inventor of the present application has determined a cylindrical optical unit which is a basic configuration of a long light source as shown in FIG. 1 in order to generate sheet light, and has determined the optimality based on the cylindrical optical unit having this basic configuration. .

In FIG. 1, reference numeral 1 denotes a long light source such as a fluorescent lamp, which may have a long structure by arranging a plurality of LEDs (light emitting elements) and the like. 2 is a reflector, 3 is a cylindrical lens disposed on the front surface of the reflector 2, and 4 is
A lens mount for holding the cylindrical lens 3;
5 ₁ and 5 ₂ are shielding plates for installing the lens mount 4 on the reflecting plate 2. Reference numeral 6 denotes a longitudinal slit serving as a temporary light source capable of changing a stop amount for stopping down the light from the long light source 1 and sending the light to the cylindrical lens 3, and 9 denotes the cylindrical lens 3 and the vertical slit 6. And a sliding barrel for holding the sliding barrel 9
The lens mount 4 is configured to be slidable in accordance with a cylindrical lens having a specific focal length. still,
When a highly directional LED or the like is used as the light source, the reflector 2 is not used.

The inventors of the present application used the above-configured cylindrical optical unit to reduce only a specific area by 50.
An attempt was made to find an optimal optical system for irradiating a sheet having a width of mm. FIG. 2 is a diagram showing a lens arrangement for obtaining an optimal cylindrical lens for the above configuration and a measuring method thereof. In FIG. 2, 1 is a fluorescent tube as a light source, and 3 is
The biconvex spherical cylindrical lens 6 is a vertically elongated stop on the vertically elongated slit 6, and 7 is an irradiation surface. A in the figure
Indicates the distance between the cylindrical lens surface 3 and the irradiation surface 7, and the measurement distances are 200 mm and 35 mm, respectively.
The dimensions were 0 mm, 500 mm, 850 mm, and 1000 mm.

In order to find the optimum cylindrical lens 3, a biconvex cylindrical lens (R = 50.0 mm, center thickness 10 mm) was used as a premise. In this analysis, the cylindrical lens 3 was placed at a position 58 mm from the surface of the fluorescent tube as the light source 1 and 52 m from the cylindrical lens 3.
The longitudinal slit 6 was arranged at the position of m.

Then, as shown in FIG. 3, the light width was measured at a pitch of 10 mm in the ± 100 mm direction from the origin with the approximate center position of the irradiation width in the short direction. FIG. 3 is a diagram schematically showing the measurement of the irradiation width, in which B indicates the irradiation width on the irradiation surface, and 8 ₁ to
8 _n indicates each measurement point. In this measurement, an optical power meter manufactured by Advantest Co., Ltd. having a sensor area of 10 mm was used as a measuring instrument.
m, 560 nm, 460 nm
The light intensity at each measurement point 8 ₁ to 8 _n in was measured. The measurement distances and irradiation widths indicated by reference signs A and B in FIGS. 2 and 3 were determined by visually judging the boundary between light and dark using a scale. However, the determination of the boundary between light and dark is a category in which individual differences occur, and in practice, subjective judgment is inevitably mixed in with the judgment.

However, as the irradiation surface moves away from the light source, the boundary between light and dark can be recognized, but the difference in light quantity between the boundary between light and dark becomes smaller. Table 1, Table 2,
The results are shown in Table 3 and FIGS. 4, 5, and 6. 4 and 5,
In FIG. 6, the left coordinate of each graph indicates each measurement distance 200
mm, 350 mm, 500 mm
The numerical values of the light amounts at the respective measurement distances of 850 mm and 1000 mm are shown.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

Table 1 shows the light quantity distribution of each measurement point at each measurement distance at a measurement wavelength of 560 nm. Table 2 shows each measurement point at each distance of 460 nm wavelength, and Table 3 shows each measurement point at each distance of 660 nm wavelength. FIG. 4, 5, and 6 show wavelengths of 560 n.
7 shows the light quantity distribution within the irradiation width at each of the measurement points at m, 460 nm, and 660 nm. From these measurement results, it can be seen that the light amount at 460 nm is slightly higher than at other wavelengths. This indicates that the shorter the wavelength of the light source used, the higher the amount of light can be obtained, but this is also related to the sensitivity range of the video camera. The measurement results are shown in Table 4 and FIG.

[0020]

[Table 4]

Table 4 and FIG. 7 show the relationship between the irradiation width at each measurement distance. As is clear from the measurement results shown in Table 4 and FIG. It can be seen that the corner exhibits approximately 4.5 °. It can be seen that this is a great improvement considering that the angle is 110 ° in the case of only the reflection plate.

Next, using the light source used for this measurement,
In order to secure an irradiation area as narrow as possible in the measurement area,
Parallel light within a narrow 50mm width (sheet-like light) in the irradiation area
In order to obtain an ideal sheet light, the slit interval of the slit 6, the cross-sectional shape and the focal length of the spherical cylindrical lens 3, and the distance between the longitudinal slit 6 and the cylindrical lens 3 are variously changed. The most suitable lens shape, focal length, and positional relationship between the light source and the irradiation surface were obtained by simulation.
That is, taking a fluorescent lamp as an example,
In order to irradiate an irradiation area with a uniform light amount in the form of a sheet light using the light source 1, the lens shape and focal length of the cylindrical lens 3 to be used, and the positional relationship between the light source and the irradiation surface are necessary. The arrangement relationship was determined by simulation.

This simulation is performed in two dimensions or three dimensions.
This is a simulation in which light emitted from a light source designated in a three-dimensional area performs an illumination distribution (irradiance distribution) on a certain light receiving surface using ray tracing.

That is, the light source 1 used as the long light source 5 is not a point light source, but a light source 1 such as a fluorescent lamp having a certain size, and light emitted from the light source is called sheet-like parallel light. Even if it is difficult to restrict the luminous flux by arranging the vertically elongated slit 6 between the light source 1 and the irradiation surface 7 (or by arranging a reflecting surface (ellipse, paraboloid) behind the light source and rectifying the luminous flux) Actually, the surface of the fluorescent tube cannot be avoided as a kind of surface light source.

However, the cylindrical lens 3 having a predetermined shape is arranged between the light source 1 and the irradiation surface 7,
Further, a vertically long slit 6 is provided between the cylindrical lens 3 and the light source 1, and the reflecting plate 2 is disposed at the rear of the light source 1. Further, the distance between the cylindrical lens 3 and the light source 1 is determined.
Alternatively, by appropriately selecting the width of the slit 6,
Light close to the parallel sheet light can be applied to the irradiation area. This is because the light quantity distribution on the irradiation surface differs depending on the focal length of the cylindrical lens 3, the slit interval between the vertically long slits 6, and the distance between the vertically long slit 6 and the irradiation area. But not
This is because light close to the parallel sheet light can be applied to the irradiation area.

The cylindrical lens 3 to be installed
Since the size of the lens is limited in mounting or design on the device, the center thickness of the cylindrical lens is 1 in consideration of mounting.
Simulation is performed for 0.0 mm and 25.0 mm.

In this simulation, if the focal length is given as the initial condition, the curvature of the lens is automatically determined. Regarding the light quantity analysis, the simulation is performed assuming that the wavelength of the light beam used for the simulation is a wavelength distribution of a general fluorescent lamp and the number of light beams in the wavelength region is 10 million. If a simulation is performed so that the lens shape reproduces a cylindrical surface, a long calculation time is required. In this simulation, the simulation is performed as a lens having a simple spherical surface instead of a cylindrical surface.

Further, a square cylindrical lens 7
Since a cylindrical long lens in which is combined is also considered, the aperture used for the lens is a square aperture, and this aperture is a temporary light emitting surface. However, the aperture size is
The diameter obtained from the value of the object-side numerical aperture is set to the opposite side, and the simulation is performed as a rectangular aperture. As a result, the effective diameter of the lens is inevitably smaller than the diagonal of the rectangular aperture, so that the light beam immediately after exiting the lens has a circular cross section, but the illuminated light emitting surface has a rectangular shape. Yes,
A simulation is performed in this state.

Under these conditions, the lens 3 having a focal length of 111.497 mm has a focal length of 55.0 mm.
Has a convex radius (convex R) of the lens having a parfocal length of 91.
The 225 mm one has a convex radius (convex R) of 45.0 mm, and the one with a parfocal length of 70.092 mm has a convex radius (convex R) of 35.0 mm. 6 is regarded as a pseudo light source and is regarded as light emission from the vertically elongated slit 6 part.
Is the height of the light emitting source. The heights of the light sources were 12 mm, 10 mm, and 7 mm, respectively.

Then, the distance between the light source and the irradiation measurement surface is
1000mm, 850mm, 500mm, 1
The distance from the position of the longitudinal slit 6 to the lens 3 was 111.497 mm, 9 mm, respectively.
When the brightness and the distribution simulation of light on the irradiation surface were set to 1.225 mm and 70.998 mm, the object-side numerical aperture was 0.2 and 0.2, respectively, depending on the effective diameter of the cylindrical lens and the state of the light source. 24. The results are shown in FIGS.

FIG. 8 shows a lens 3 having a center thickness of 10 mm, a focal length of 111.497 mm, and a convex radius (convex R) of 5 mm.
In the case of 5.0 mm, the object height of 12 mm, and the interval between the vertically long slit 6 and the lens 3 of 111.497 mm, the parfocal distance is 91.97 mm.
225 mm, convex radius (convex radius) 45.0 mm, object height 1
0 mm, distance between vertical slit 6 and lens 3 91.225
mm, parfocal length 70.998 mm, convex radius (convex R) 35.0 mm, object height 7 mm, vertical slit 6
When the distance between the lens and the lens 3 is 70.998 mm,
Distance from light source 1000mm, 850mm, 500m
It shows the brightness at m and 150 mm and the distribution on the irradiation surface.

Similarly, FIG. 9 shows that when the lens 3 having a center thickness of 25 mm is used, the focal length is 111.497 mm, the convex radius (convex R) is 55.0 mm, the object height is 12 mm, and the distance 111 between the longitudinal slit 6 and the lens 3 is 111. In the case of .497 mm, the parfocal distance is 91.225 mm, and the convex radius (convex radius) is 45.0 m.
m, the object height is 10 mm, and the distance between the vertically elongated slit 6 and the lens 3 is 91.225 mm.
m, convex radius (convex radius) 35.0 mm, object height 7 mm, distance 70.982 mm between the vertically elongated slit 6 and the lens 3, distances from the light source are 1000 mm and 850 m, respectively.
It shows the brightness at m, 500 mm, and 150 mm and the distribution on the irradiation surface.

As a condition for comparing the brightness under the simulation conditions, the light emitting source is assumed to be completely diffused light. The ratio is calculated with the brightness under the brightest condition as 100%. It is assumed that the luminance per unit area is the same under each condition. Under these conditions, Table 5 shows a numerical comparison of the emission area from the simulation results.

[0034]

[Table 5]

As is apparent from Table 5, the focal length 11
The emission area is 144 mm ₂ for 0.497 mm.
Is 100.00%, the parfocal distance is 91.225m
m, the emission area is 100 mm ₂ ,
It can be seen that, with a light emitting area of 49 mm ₂ , a brightness of 34.03% is obtained for 9.44% and a parfocal distance of 70.982 mm. Next, Table 6 shows the difference in the difference in the center thickness of the lens 3 from the above simulation results, that is, the comparison result in the light beam taking-in angle.

[0036]

[Table 6]

As can be seen from Table 6, the center thickness is 25 mm.
The lens 3 has an object-side numerical aperture of 0.24, so that the illumination surface has a brightness of 100.
%, The lens 3 having a center thickness of 10 mm has an object-side numerical aperture of 0.2, so that the brightness ratio is 6%.
9.44% is obtained. As a result, the results shown in Table 7 can be obtained by comparing the brightness of the lens 3 as a whole through the above simulation.

[0038]

[Table 7]

That is, as can be seen from Table 7, for the lens 3 having a focal length of 110 mm, a center thickness of 10 mm and 25 mm, the brightness coefficients are 5.76 and 8.2, respectively.
9 can be obtained, and the lenses 3 having the focal length of 90 mm, the center thickness of 10 mm, and the 25 mm can obtain the brightness coefficients of 4.00 and 5.76, respectively, and further have the focal length of 70 mm and the center thickness of 10 mm And 25mm
Lens 3 can obtain a brightness coefficient of 1.96, 2.82.

FIG. 10 is a graph showing the result. As can be seen from this result, since the light source 1 has a certain object height, it is considered that the light source 1 does not become completely parallel light as a whole, and therefore the light amount distribution changes depending on the position of the irradiation surface 7. As close as possible to parallel light,
Under the above-described limited conditions, it may be understood that it is better to use the one having a focal length of 110 mm for the purpose of irradiating the irradiation area with light having a large light quantity distribution light as uniform as possible.

Next, in order to evaluate a prototype based on the above simulation results, in the cylindrical optical unit shown in FIG. 1, a fluorescent light source was used as the light source, and the slit width of the vertical slit 6 was variously changed. ,
The change of the irradiation width (B) on the irradiation surface 7 shown in FIG. 2 was examined.

Table 8 shows that, for the slit width (x),
The irradiation distance from the light source 1 is 500 mm, 750 mm, 1
The change of the irradiation width (B) at the position of 000 mm is shown.

[0043]

[Table 8]

As can be seen from Table 8, it can be seen that by adjusting the slit width, the sheet-shaped parallel light can be irradiated to the irradiation area.

Next, in order to evaluate a prototype based on the above simulation results, a fluorescent light source was used as the light source 1 in the cylindrical optical unit shown in FIG. Case, and the slit width is 5 mm,
In the case where a light source in which nine LEDs were vertically arranged in series was used as the light source 1, a change in the irradiation width (B) on the irradiation surface 7 shown in FIG. This measurement was performed using NARUX Co., Ltd. (address: 3-2 Minamieguchi, Higashiyodogawa-ku, Osaka-shi)
-30 Representative Director Seiichiro Kitagawa) on March 15, 1999 from 2:30 to 5:00 pm with testers Matsushita Giken Co., Ltd. Sato, Ayara Sangyo Co., Ltd. Nakamura, Narux Co., Ltd. Ida, and Hatate.

Table 9 shows that the fluorescent light source 1 was used, and the light sources 1 to 5 just before the light source 1 when the slit width was 20 mm.
Table 10 shows the light amount and the irradiation width (B) at the irradiation positions at a distance of 00 mm and 850 mm. Table 10 shows the light source 1 in which the nine LEDs were arranged in series, and the slit width was set to 5 mm. Immediately before the light source 1, 500
The light amount and the irradiation width (B) at the irradiation positions at a distance of 850 mm and 850 mm are shown.

[0047]

[Table 9]

[0048]

[Table 10]

At the time of this measurement, the same measuring equipment as used in the prior art was used. In addition, using a light source of both a fluorescent light source and a serially arranged LED light source, the light source was irradiated with water vapor mist ejected from a plurality of holes of a predetermined pipe, and this was photographed with a video camera from the side.

FIG. 11 (a) is a photograph taken by irradiating a steam mist with a fluorescent lamp straight tube and photographing the mist from the side with a video camera, and FIG. 11 (b) shows 10 LEDs.
Using a light source arranged in series, irradiate the steam mist,
This is a photograph taken with a video camera from the side. As is clear from the photographs of FIGS. 11A and 11B, L
Even with a light source using an ED, it can be known that a water vapor mist farther than a fluorescent light source is captured.

As is apparent from the results of these simulations and evaluation measurements, a vertically long slit 6 having a variable width and a lens 3 having a specific focal length and thickness are arranged. The lens mount 4 can be used to move between the sliding barrel 9 and an irradiation area, and according to a desired irradiation area,
A long sheet light generation device that is bright and has a uniform light amount distribution can be provided.

The long sheet light generating device according to the present embodiment is applied to an air flow visualizing device, and the steam mist is radiated from the side by the device, captured by a digital video camera, and the digital image data is obtained. Based on a similar pattern of tracer movement captured using a sequential rejection method based on luminance difference accumulation, a PIV (Pattern Imaging Velocimetr
The analysis according to y) is performed to obtain the speed vector and the average speed vector of the tracer. This method is the same as the conventional method, so a detailed description is omitted.However, since parallel light can be irradiated only to the irradiation area, it is possible to irradiate the irradiation light efficiently without dispersing it. The generated light does not interfere with the capture of the water vapor mist tracer as so-called noise, and an excellent airflow visualization device can be provided.

When the image data is obtained by photographing the measurement area (space) with a video camera, the tracer irradiated with the light beam does not react to the scenery behind the measurement area as in the related art. A black screen or the like may be arranged at a position that does not affect the airflow so that the image can be more clearly captured.

[0054]

According to the long sheet light generating apparatus of the present invention, a predetermined slit 6 and a predetermined cylindrical lens are arranged at a predetermined position in a light source, and the position of the vertical slit 6 and the position of the lens are determined. In addition, since the irradiation position is appropriately optimized, it is possible to perform irradiation close to parallel light (sheet-like light) on the irradiation area, and it is possible to perform irradiation efficiently with respect to irradiation, and Since parallel light irradiation is possible, it is possible to irradiate only the irradiation area, and it is possible to efficiently irradiate only the necessary irradiation area without dispersing the irradiation light. Thus, it is possible to irradiate the leak tracer or the space-floating substance existing there and to suppress the generation of so-called noise caused by the reflected light.

As a result, when the airflow visualizing device is applied, the area other than the irradiation area is not irradiated, and the capture of the water vapor mist tracer is not interfered with and no noise is generated. It has an excellent effect.

By appropriately adjusting the cylindrical lens and the slit width as described above, it is possible to irradiate not only a fluorescent light source but also a light source having a plurality of LEDs arranged in a long shape to a distant region. In addition, since the sheet-like parallel light can be irradiated, there is an effect that the apparatus can be configured more efficiently and lighter. In particular, compared with the use of argon laser light or solid-state laser light, the safety to the human body is high, and the device can be prevented from being large-scale. These lasers generate a large amount of heat, which is wasteful. Energy is required, and the energy conversion efficiency is poor, but the light source using the LED, compared with this, brings about energy saving and also generates very little heat, so that the surrounding airflow environment and the like are not disturbed. An extremely excellent light source can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan sectional view of the long light source 5 as viewed from above.

FIG. 2 is a diagram showing a lens arrangement and a measuring method of an airflow lens analysis for obtaining an optimal cylindrical lens for the above configuration.

FIG. 3 is a diagram schematically showing a measurement of a light amount in an irradiation width direction in the measurement of FIG. 2;

FIG. 4 is a diagram illustrating a light amount distribution at measurement points in each sheet width direction at each measurement distance at a wavelength of 560 nm.

FIG. 5 is a diagram showing a light amount distribution at measurement points in each sheet width direction at each measurement distance at a wavelength of 460 nm.

FIG. 6 is a diagram showing a light amount distribution at measurement points in each sheet width direction at each measurement distance at a wavelength of 660 nm.

FIG. 7 is a diagram illustrating a relationship between irradiation widths at respective measurement distances.

FIG. 8 is a diagram showing a comparison simulation result of a light amount distribution due to a difference in a focal length and an aperture when a spherical cylindrical lens having a center thickness of 10 mm is used.

FIG. 9 is a diagram illustrating a simulation result of a light amount distribution due to a difference in a focal length and a diaphragm when a spherical cylindrical lens having a center thickness of 25 mm is used.

FIG. 10 is a graph showing a brightness ratio at each focal length and each center thickness.

FIG. 11 (a) is a photograph taken by irradiating steam mist using a straight tube of a fluorescent lamp and photographing the mist from the side with a video camera, and FIG. LED
Using a light source arranged in series, irradiate the steam mist,
This is a photograph taken with a video camera from the side.

FIG. 12 is a diagram showing a basic schematic structure of an airflow visualization device.

FIG. 13 is a detailed configuration diagram of the long light source 105 with a reflector used in the conventional airflow visualization device and the like.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Light source 2 Reflector 3 Spherical cylindrical lens 5 ₁ , 5 ₂ Shield plate 6 Vertical slit 7 Irradiation surface 8 ₁ -8 _n Measurement point 9 Sliding lens barrel 10 Lens mount

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshitsugu Nakamura No. 779, Tanokura, Oaza, Minami-Nasu-cho, Nasu-gun, Tochigi Prefecture F term in Ayara Sangyo Co., Ltd. (reference) 2F034 AA02 AB01 AB04 DA01 DA07 DA15

Claims (1)

[Claims] 1. A vertical slit for narrowing irradiation light between a light source and an irradiation area, and a cylindrical lens having a predetermined focal length, wherein a slit width of the vertical slit and an arrangement position of the cylindrical lens are slidable. A long sheet light generation device, characterized in that: