JPH1082973A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device capable of sufficiently uniformly irradiating a transparency from the rear side. SOLUTION: This optical device 10 is provided with a housing 12 provided with a rear wall 35 and a light-passable front opening part 16, at least one light source 36 emitting the light forward and backward in the housing 12 and plural parallel convex lens surface groups 32 placed backward the light source 36, being a lenticular lens sheet 30 opposing the linear light source 36 and slenderly extending in the horizontal direction. The lens surface groups 32 includes the lens sheet 30 advancing along a certain path and forming a pattern geometrically following the outline of the light source 36 and a rear surface 34 for converting the light emitted backward from the light source 36 into forward direction behind the lens surface groups 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical device useful for illuminating a transparent display.

[0002]

2. Description of the Related Art Irradiation displays for displaying images supported on a transparent substrate are well known, and are widely used for advertisements and other displays. Generally, such displays include a housing that is enclosed except for a light opening in the front, across which a transparent positive with an image is placed. The light source is located behind the transparency inside the housing. As the light source, a plurality of elongated light sources such as fluorescent tubes are usually used. A diffuser in the form of a diffusion sheet is provided between the light source and the transparency so that the light source itself is not projected through the transparency having an image. While these types of displays can be used for transparency supporting ordinary two-dimensional images, such as those formed from photographs, more recently, the use of transparency with integral images has also been known. Is coming.

[0003]

As known integral image elements (integral image elements), a lenticular lens sheet, a fly-eye lens sheet or a barrier strip sheet, and a three-dimensional integral image aligned with these lens sheets In some cases, a three-dimensional image can be observed without using a device such as special glasses.
For such an image forming body and its structure, see "3D Imaging Technology" by Okoshi Takanori (New York,
Academic Press, 1976 edition). An integral image element having a lenticular lens sheet (a sheet having a plurality of adjacent, parallel, elongated, and partially cylindrical lenses) is described in the following U.S. Patents: That is, US Pat.
No. 54, No. 5,424,533, No. 5,241,60
No. 8, No. 5,455,689, No. 5,276,478
No. etc. It is also described in U.S. patent application Ser. No. 07 / 931,744, which has been granted a patent. The integral image body provided with the lenticular lens sheet is used by combining vertically divided image pieces. In the case of a three-dimensional integral image, since the image pieces are aligned with the lenticules,
When the lenticule is positioned in a direction perpendicular to the line of sight of the observer, a three-dimensional image can be seen. The image can be laminated (ie, glued) to an integral image or lenticular lens sheet for convenience. Similar integral image bodies are described in U.S. Pat. Nos. 3,268,238 and 3,5.
38,632. Rather than displaying one or more three-dimensional images, these are mainly a number of two-dimensional scenes (a series of scenes representing a plurality of unrelated scenes and movements) when viewed at different angles with respect to the image body. , Etc.) are displayed separately.

At least for ordinary two-dimensional images,
It is desirable to irradiate the transparency with the image uniformly from behind. This is especially true for larger displays with a plurality of elongated light sources that are laterally spaced. Since the light irradiation amount is small in a region corresponding to the space between the light sources on the transparency, the diffuser sheet as described above is used. However, even with the use of diffuser sheets, uniform illumination of transparencies by linear or other light sources cannot yet be achieved, so diffuser sheets are not entirely satisfactory. In contrast, US Pat.
195,818 and 5,224,770 describe a reflector configuration comprising a group of reflectors having parallel V-grooves and extending across an elongated light source. However, such designs inherently have the problem of non-uniform transparency illumination. The reason for this is pointed out by the present invention and will be described below.

Accordingly, it is desirable to provide an optical device capable of irradiating the transparency sufficiently uniformly from behind.

[0006]

SUMMARY OF THE INVENTION The present invention realizes that even when a simple reflector or a diffuser is used, the irradiation intensity at the position where the transparency is to be installed is always reduced between the light sources. This is because the luminance always decreases as the distance from the light source increases. Because of this physical law, various conventional reflector or diffuser designs that attempt to spread the light more evenly between the light sources have been less effective. The present invention has realized, using a method different from the conventional method, that the cause of the above problem is simply a space existing in a place where no light source exists (such as between a plurality of light sources). This cause can be eliminated by increasing the number of light sources, but this method may not be practical in view of manufacturing and operation costs. However, the present invention intends to obtain an effect equivalent to this method.

As described above, the first embodiment of the present invention provides an optical device including the following. A) a housing having a rear surface and a front light opening through which light passes; b) at least one light source for irradiating light forward and backward within the housing; c) behind the light source within the housing. A lenticular lens sheet positioned and facing the linear light source, comprising a plurality of parallel, elongated, laterally extending convex lens surface groups;
A lens surface group extending along a path to form a pattern that geometrically follows the contour of the light source; d) a reflection that forwardly redirects light emitted backward from the light source behind the lens surface. And a surface.

In a second embodiment of the present invention, an optical device includes: A) a transparency for holding an image for display; b) a light source positioned behind the transparency and illuminating the transparency, emitting light forward and backward; c) a light source A lenticular lens sheet positioned rearward of and facing a linear light source, the lens sheet group comprising a plurality of parallel, elongated, laterally extending convex lens surfaces, the lens surfaces extending along a path to define a light source contour. A) a lens sheet that forms a pattern that conforms geometrically to the lens surface; and d) a reflective surface that redirects forwardly emitted light from the light source behind the lens surface.

In another embodiment of the present invention, a light source, a lenticular lens sheet positioned behind the light source and having a lens surface facing the light source, and a reflector that changes light emitted rearward behind the lens surface forward. including.

The optical device of the present invention irradiates light sufficiently uniformly on an image of a transparency located in front of a light source even when there is a considerably large area behind the transparency where no light source actually exists. Can be. In an optical device including a certain number of light sources, irradiation uniformity can be improved.
It is also possible to reduce the number of light sources while maintaining irradiation uniformity.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

In the drawings, to facilitate understanding, identical elements are denoted by the same reference numerals as much as possible.

Referring to FIG. The optical device shown in the cross-sectional view of FIG. 1 is similar to the device shown in FIG. 2, except that the lenticular lens sheet used in the present invention is not used. The device shown in FIG. 1 includes a plurality of parallel extending identically shaped linear light sources 36a, 36b (shown extending vertically from the plane of the figure), such as a linear fluorescent bulb. The diffuser sheet 18 is located in front of the light sources 36a and 36b,
A transparency having an image is arranged adjacent to the front of the diffuser sheet 18. The image is further viewed from a forward position.

The reflector 8 is a flat specular reflector (a similar effect can be obtained with a diffuse reflector). The light beam 9 emitted from the rear side of the light source 36a always spreads outward and travels to the reflector 8, where it is reflected by the reflector 8 and further spreads. Accordingly, the total amount of light provided to the diffuser 18 by the light beam group 9 reflected in this way is larger than the light amount simply provided by the light beam group 14. However, on the other hand, the light intensity on the diffuser 18 is
It decreases reliably as the light source 36a moves from the light source 36a to the light source 36b in the lateral direction. The same result can be obtained with the light source 36b. As a result, even when the reflector 8 is provided, the light irradiation on the diffuser 18 is necessarily reduced as the light source 36a, 36b moves toward the intermediate point 18a between the light sources. Will be.

Referring now to FIG. FIG. 2 shows the optical device of the present invention. The device 10 includes an opaque housing 12, except that the front opening 16 is transparent. Light aperture 16
Is defined by a light transmissive diffuser 18 (such as a transparent white plastic sheet) extending across an area defined by the front perimeter and a transparency 20 located in front of and adjacent to the diffuser 18. Transparency 20 extends similarly to diffuser 18 and holds a visible image for display. In FIG. 2, the diffuser 18 and the transparency 20 are shown in a largely cut-out state so that the inside of the optical device 10 can be clearly seen. Transparency 20 can hold any type of image, such as a general two-dimensional image (such as a stretched image of a conventional photograph), or it can hold an integral image as described below.

As shown in FIG. 3, a plurality of linear light source groups 36 of the same shape such as a linear fluorescent lamp are arranged inside the housing 12 and emit light toward the diffuser 18 forward and backward. . A lenticular lens sheet 30 having a conventionally well-known structure is disposed adjacent to the opaque rear wall 35 of the housing 12. Lens sheet 30
Has a flat rear surface 34 and a plurality of parallel extending elongated linear cylindrical lens surfaces 32 disposed on the front surface. The rear surface 34 is preferably itself reflective. To achieve this, the rear surface 34 is
The rear surface 34 is finely polished (for example, fine sandblasting) with a slightly diffuse reflection surface integral with the rest of the zeros.
Is preferred. Alternatively, the back surface 34 may simply be formed from a flat, polished surface and may rely only on internal reflection at the back surface 34 (although this is less preferred). Alternatively, a separate reflective layer (a reflective metal or metal oxide coating) may be provided to make the back surface 34 reflective. For example, the rear wall 35 can reflect light forward. Such a separate reflective layer is preferably located immediately adjacent the back surface 34.
The rear wall 35 can be omitted particularly when a reflective metal layer is provided adjacent to the rear surface 34.

The lens surface 32 has a pattern shape along the contour of the light source group 36. The “outline” of the light source group refers to the outline of the two-dimensional direct projection from the light source group 36 to the front light opening 16 (the “direct projection” means that the light beam group moves from the rear to the front in the front light opening). 16 to 90 °). In other words, since the contour of the light source group 36 is a straight line, the lens surface 32 follows the light source group 3 along this contour.
6 are arranged in a linear pattern parallel to 6. Accordingly, when the light source group 36 is driven, the transparency 20 can be observed from the front. However, in the present application, it should be understood that such an "along the contour" condition may not necessarily be accurate (i.e., not parallel to the contour). The uniformity of the light distribution on the diffuser surface decreases,
Some effect can be obtained even if the lens surface group deviates from the contour. This feature can itself be used to enhance the aesthetic appearance if it is desired to change the light uniformity as desired.

Next, the efficient filling of the diffuser 18 with light at an intermediate position of the light source group 36 using a lenticular lens sheet will be described. This first requires an understanding of the lenticular geometry and optical properties, as well as the application of such optical properties to the geometry of an optical device such as device 10. An application form will be described below with particular reference to FIGS. 4 to 8. Light striking the diffuser 18 arrives in three paths.
The first light is light emitted backward from the light source 36 and is imaged by the lenticule on the rear surface 34 of the lenticular sheet, and is then turned forward by the lenticule immediately adjacent, such as the lenticule 42. This is called the first satellite image. The second light forms an image on the rear surface of the lenticular lens sheet and is turned forward by a second adjacent lenticule, such as lenticule 43. This is called the second satellite image. Theoretically, higher-order satellite images exist, but the intensity is so weak that it does not matter. The third light is light emitted directly forward from the light source 36 to the diffuser 18 (i.e., occurs without any reflective surface in the optical device). This is shown in FIG.

Light paths to which the first and second satellite images can be applied for the lenticular geometry lenticular lens sheet 30 are shown in FIGS. 4 and 5, respectively. In FIG. 4, light ray 40 is incident on lenticule 41 and impinges on flat rear surface 34 and illuminates intercept point 44. Point 44 is the subject of the next adjacent lenticule 42 and light is refracted from lenticule 42 along refraction path 45. The angle “b” according to Snell's law (the law of refraction) depends on the initial angle of incidence “a” with respect to the lenticule centerline 41 c and the refractive index “n” of the lens sheet 30 with respect to the external refractive index “n ₀ ”. It is determined. For reference, the thickness “t” of the lens sheet 30 is substantially the same as the focal length of the lens surface 32. The thickness is measured from the top of the convex lens surface (that is, the maximum thickness is measured). However, t need not be the same as the focal length of the lens, and may be modified to change the distribution of intercept points resulting from the first and second satellite images, if desired. Ray 40 is thus refracted to ray 40r. Point 44 is targeted by lenticule 42 at an angle "c" from center line 42c of lenticule 42.

Light ray 60 is a reflection path of photons (photons) from point 44 to lens surface 32 of lenticule 42. Again, according to Snell's law,
Ray 60 is refracted at a new angle "d" into ray 60r. The distance between the lenticular lenses 41 and 42 and the other similar lenticules in the lens sheet 30 is “p”.
It is. Based on the following geometric relationships, a,
The values of b, c and d can be determined from equations (2), (5) and (7).

[0021]

(Equation 1) FIG. 5 is substantially the same as FIG. 4 except that the second satellite image is analyzed. The above equation is expanded to cover the second satellite image in a similar way.

[0022]

(Equation 2) Similar analysis can be performed on higher order satellite images, but the amount of light reflected from point 504 at angles greater than angle e decreases according to the rules associated with Lambertian surface emission.

The surface treatment of the rear surface 34 of the lens sheet 30 affects the light transmission efficiency along the refracted ray 60r. A diffuse white surface is preferred over a surface without a flat finish. In addition, rather than a flat polished surface, the back surface 34 subjected to diffusion sandblasting is used.
Is preferred. In any case, a metal or metal oxide can be added to the back side of the back surface 34 to improve the reflectance.

[0024] Geometry Figure 6 apparatus is a part of the first satellite image shown in FIG. In FIG. 6, for any photon path 40 exiting perpendicularly from the surface of the light source 36 and intercepting the lenticular lens sheet 30, the angle of incidence is a. Therefore, x
The intercept distance from ₀ (the central axis of the center of the light source 36) is as follows.

[0025]

X _i = g · tan a (11) where g represents the distance from the center of the tube to the lenticular plane 002.

As can be seen from the equation described in the "Lenticule Geometry" section above, photons are refracted from the lenticular lens sheet 30 at an angle d and become new rays 60r. This photon strikes the diffuser 18 at a point 70 at a distance k ₁ from x ₀ . (Sometimes referred to as x translation) additional lateral translation of the rays 60r is represented by x _r, can be calculated as follows.

[0027]

Equation 4] _{x r = (h + g)} tan d (12) where h represents the distance from the diffuser 18 to the shaft x _0, g represents the distance from the axis x ₀ to the lenticular lens sheet 30. For any value a, k ₁ = x _i + x _r
Note that

A series of calculations similar to the above can be performed on the second satellite image, except that c is replaced by e
And d must be replaced with f.

As shown in FIG. 7, it is convenient to use a computer spreadsheet to calculate a series of intercepts similar to point 70 that result from other photon incident paths similar to path 40. FIG. 7 shows FIG.
7 is similar to FIG. 3, but shows other ray path groups.

In FIG. 7, the incident angles 102, 1 which are increasing are shown.
A series of photon paths incident at 03, 104, and 105 are refracted and then photon paths 102r and 103, respectively.
r, 104r, 105r, and intercepts the diffuser 18 at "hit" points 112, 113, 114, 115. Each point 112, 113, 11
The distance k ₁ in FIG. 6 corresponding to 4,115 can be calculated and displayed as a graph. Then, it can be seen that the point groups are arranged at equal intervals in the portion where the irradiation is performed uniformly on the diffusion surface.

FIG. 7 also shows that the light emitted backward from the light source 36 is transmitted by the lenticular lens sheet 30 at a position between adjacent light sources.
Once again, the focus is set. Light emitted backwards does not simply reflect as with a simple planar reflector, nor does it reflect and scatter as with a flat diffuse reflecting surface alone. Therefore, the light irradiation on the diffuser 18 at the intermediate point with the adjacent light source 36 can be actually increased, so that the light irradiation on the diffuser 18 toward the intermediate point with the adjacent light source 36 does not always become weak. .

FIG. 8 is substantially the same as FIG. 7, except that a similar group of photon paths are emitted from the front side of the light source 36 and directly intercept the diffuser 18. Again, the path groups 201, 202, 203, 204
Exits vertically from the surface, but proceeds in a direction toward the diffuser 18. Each route has points 211, 212, and 2
At 13 and 214, the diffuser 18 is intercepted. These intercepts k ₀ are obtained by the following equations.

[0033]

K ₀ = h · tan a (13) The value a used in the analysis of the light distribution is the same value as that used in the analysis of the refraction photon path group, except that x ₀ is the center. It is measured clockwise from the Y axis 291 of the coordinate system.

Intercept hit points 211 and 2
12, 213, 214, etc. are calculated using the spreadsheet used above and adding an appropriate formula.

When the above-described analysis method is used, in the optical assembly manufactured based on FIG. 3 and having the parameters shown in Table 1 below, the light beam intercept on the diffuser 18 (in FIG. 9, described as “photon path intercept”) A spreadsheet programmed in Microsoft Excel was used to analyze the data. In Table 1, k ₀ , k ₁ ,
All linear dimensions including k ₂ is normalized to the bulb spacing S _b. Since thereby applying the same calculation sets for various S _b, we can simplify the design of the light box is considered that the dimensions are significantly different.

[0036]

[Table 1] FIG. 9 is a graph of the ray intercept between adjacent light source groups 36. The vertical axis shows the ratio normalized box thickness g + h a (through the lamp center) to the lamp spacing S _b. The horizontal axis shows the position of the lamp interval as a ratio (ie, there may be another lamp at position 1). Unlike the use of the flat reflector described with reference to FIG. 1, the intercept density at the midpoint between adjacent light sources 36 does not fall to a minimum, but increases due to the effect of light redirected by the lenticular lens sheet 30. I do. The intercept density is
Due to the imperfect reflectance efficiency from the lenticular lens sheet 30 and the rear surface 34, the light intensity may not correspond one-to-one. Of course, this is a feature that can be controlled to some extent at the manufacturing stage to optimize performance or cost.

Therefore, utilizing the above type of analysis as a technique for manufacturing an optical device such as the device 10, the light source group 36
The diffuser 18 can be irradiated most uniformly under the restrictions such as the number of the openings and the size of the front opening 16. The above analysis also assumes that the emitted photon path is perpendicular to the light source. By taking into account the diffuse nature of the light source surface and the light intensity that decays with distance, a more complete analysis can be performed. However, the analysis presented above is a conventional practical first-order approximation that meets most objectives. Alternatively, in an apparatus having the above-described predetermined restrictions, as a second technique, there is a method of simply determining the distance between the lenticular lens sheet 30 and the diffuser from the light source 36 based on experience. This technique is performed by simply manually changing the spacing until a sufficiently uniform illumination on the diffuser 18 is observed. In addition, Imaging Technology International,
Lenticular lens sheets with lenticules of different sizes, commercially available from Duluth, Georgia, USA, etc., may be used. Based on the number and type of light source groups and the preselected constraints on the target area of the light source group, the target area (diffuser 18
In order to suppress the non-uniform irradiation as much as possible, either of the above techniques may be used as desired. The non-uniformity of the light irradiation can be determined from the measurement of the light intensity in the irradiation target area and the calculation of the standard deviation and the variance by the statistical technique.

Next, reference is made to FIG. FIG. 10 shows a cross-sectional view of another optical device 10a of the present invention. The structure of the device 10a is similar to the device 10 shown in FIGS. However, the apparatus 10a includes a curved image holding transparency 20a located in front of the curved diffuser 18a. Transparency 20a and diffuser 18a both extend to rear wall 35a (transparency 20a
Note that the diffuser 18a bends concavely around the linear light source group 36). The two light sources 36, which are also linear as in the device 10, are located behind the diffuser 18a and
It is located in front of the lenticular lens sheets 30a. Each lenticular lens sheet 30a is similar to the sheet 30 of the device 10, but each sheet 30a only extends laterally from behind the corresponding light source 36 (ie, 2).
There is no lenticular lens sheet extending behind and between the two light source groups 36). If the curvatures of the diffuser 18a and the transparency 20a and the position of the light source group 36 are properly adjusted, a very uniform light irradiation can be obtained on the diffuser 18a.

FIG. 11 shows different patterns of lenticular lens elements. In FIG. 11, a light source 300 having a circular contour such as a spherical light source is provided. The lenticular lens sheet 30b in this case has a parallel and elongated convex lens surface group 32b, and these surfaces form a pattern of a plurality of concentric circles along the circular contour of the light source 300. When referring to the shape of the lens surface as "elongate", the surface does not need to be straight unless otherwise indicated.
In addition, the lenticular lens sheet 30b can be manufactured in any mode described in relation to the lens sheet 30 described above. The diffuser and the image-bearing transparency can be arranged continuously in front of such a light source. The light source 300 and the lens sheet 30b may or may not use a diffuser as a light source that projects light forward.

FIG. 12 is a cross-sectional view of an apparatus to which the arrangement shown in FIG. 11 is applied. In the optical device 10b of FIG. 12, the housing 12b is opaque but includes a front light opening defined by a convex lens which is a light transmissive Fresnel lens 302. The housing 12b has a rear wall 35b, and the lens sheet 30b is disposed against the rear wall 35b. The rear wall 35b is, like the rear wall 35 described above, a lens sheet 3
0b may have a surface that reflects light forward and adjacent. The optical assembly 10b of FIG.
A diffuser can be located adjacent to and in front of the lens. When it is desired to display an image having an image holding transparency using the optical assembly 10b, the transparency adjacent to the Fresnel lens 302 and in front of the lens can be set. Also, transparencies can be omitted and the optical assembly 10b can be used as a light source for projecting light forward for other purposes, with or without a diffuser. The Fresnel lens 302 has a property of collimating light traveling forward through the lens.

In the present invention, the lenticular lens sheet has been described as having a convex lens surface. Such a lens surface may be physically convex in that it has physically convex portions (preferred form), but instead, a convex lens may be used if the lens surface of the lenticule is physically convex. The functional convex surface may be used in that the same optical effect as obtained can be obtained. In the latter case, the lens sheet uses multiple regions that are physically flat on both sides but have different refractive indices when passing through the lens. These regions (along with curved, planar, or other shaped sheet outer surfaces) are configured to optically polarize light rays, similar to lenticular lens sheets having physically convex lens surfaces. In the present invention, the rear surface of the lenticular lens sheet may also be bent to enhance the lens effect or to compensate for a curved focal plane inherent to the lens structure. As a result, the curve on the rear surface of the lens sheet has a shape that matches the curve on the focal plane of the lens.

In an embodiment in which the light distribution is desired to be changed, the entire lens sheet such as the lens sheet 30 may be bent, or may be bent into a concave or convex shape around an axis parallel to the axis of the linear light source. can do. As used herein, a “linear” light source refers to a light source that includes a row of individual light sources (such as a row of spherical incandescent spheres).

The light distribution applied to the diffuser 18 can be changed by changing the characteristics of the reflection rear surface 34.
For example, when it is desired to provide more diffuse satellite images, a diffuse reflection area band 400 may be provided as shown in FIGS. FIG. 13 shows a diffuse reflection area band 40.
FIG. 14 shows the effect on the first satellite image when 0 is provided, and FIG. 14 shows the effect on the second satellite image.
The region group 400 may be colored if a color effect is desired, or may be angled if another effect is desired.

As for the image type possessed by the transparency, as described above, a two-dimensional image obtained by extending a conventional photograph or the like can be considered. However, when a lenticular lens sheet is used, an integrated image may be used. (Thus, an image is a combination of a plurality of two-dimensional image pieces as described above. An integral image specifically configured for a lenticular lens sheet may be referred to as a "lenticular image.") The image piece is an integral lens. Being aligned with the individual lenses of the sheet, each image is visible when the observer's line of sight is at the correct angle to the imaging element. The integral image may be one or more three-dimensional images, one or more two-dimensional images, or an image combining these. “Three-dimensional image” refers to an integral image having a depth component that can be visually recognized when viewed through a lens. "Depth component" refers to the ability to at least partially see around an object in a scene. This is obtained by intersecting lines from multiple oblique views of the same scene (ie, views of the scene at different angles). That is, the three-dimensional image must include at least two views for one scene. A “two-dimensional image” refers to an image that has no visible depth component in the finished image.

The present invention has been described using the preferred embodiments. However, variations and modifications can be made by those skilled in the art without departing from the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical device showing the operation of a conventional reflecting surface.

FIG. 2 is a perspective view of the optical device of the present invention.

FIG. 3 is a cross-sectional view taken along the line 3-3 in FIG. 2;

FIG. 4 is a diagram illustrating a method of determining a geometric position of a light source and a lenticular lens sheet used in the apparatus of FIG. 2;

FIG. 5 is a diagram illustrating a method of determining a geometric position of a light source and a lenticular lens sheet used in the apparatus of FIG. 2;

FIG. 6 is a diagram illustrating a method of determining a geometric position of a light source and a lenticular lens sheet used in the apparatus of FIG. 2;

FIG. 7 is a diagram illustrating a method for determining a geometric position of a light source and a lenticular lens sheet used in the apparatus of FIG. 2;

FIG. 8 is a diagram showing a method of determining a geometric position of a light source and a lenticular lens sheet used in the apparatus of FIG. 2;

FIG. 9 is a graph showing a calculated light distribution in the apparatus of the present invention.

FIG. 10 is a cross-sectional view of another optical device of the present invention.

FIG. 11 is a front view showing the shape of a lenticular lens sheet located behind a nonlinear light source in still another optical device of the present invention.

FIG. 12 further uses a collimating lens, FIG.
FIG. 2 is a cross-sectional view of a light source other than that shown in FIG.

FIG. 13 is a diagram showing an example in which a diffuse reflection area band is provided to increase the number of diffuse satellite images in still another optical device of the present invention.

FIG. 14 is a diagram showing an example in which a diffuse reflection area band is provided in a further optical device of the present invention to increase the number of diffuse satellite images.

[Explanation of symbols]

002 lenticular surface, 8 reflectors, 9.1
4,40,40r, 60,60r light beam, 10,10a
Optical device, 10b Optical assembly, 12, 12b
Housing, 13 front peripheral portion, 16 opening, 18 diffuser, 18a midpoint, 20, 20a transparency, 30, 30a, 30b lens sheet, 3
2, 32b lens surface, 34 rear surface, 35, 35a,
35b rear wall, 36, 36a, 36b, 300 light source,
40, 102r, 103r, 104r, 105r, 20
1, 202, 203, 204 light path, 41, 43 lenticule, 41c, 42c center line, 44, 70,
504 intercept point, 45 refraction path, 1
02, 103, 104, 105 Incident angle, 112, 1
13, 114, 115, 211, 212, 213, 21
4 hit points, 291 Y axis, 302 Fresnel lens, 400 diffuse reflection area.

Claims (1)

[Claims] 1. a) a housing having a rear surface and a front light opening through which light passes; b) at least one light source emitting light forward and backward within said housing; c) said light source within said housing. A lenticular lens sheet located behind the light source and facing the linear light source, comprising a plurality of parallel, elongated, laterally extending convex lens surfaces, wherein the lens surfaces extend along a path; An optical device comprising: a lens sheet that forms a pattern that geometrically conforms to the contour of the light source; and d) a reflective surface behind the lens surface that redirects forwardly emitted light from the light source forward.