USOOSS 86347A
`5,386,347
`[11] Patent Number:
`[19]
`Umted States Patent
`
`Matsumoto
`[45] Date of Patent:
`Jan. 31, 1995
`
`[54]
`
`ILLUMINATING APPARATUS AND A
`METHOD OF MANUFACTURING AN EDGE
`THEREIN
`LIGHT CONDUCTOR FOR USE
`Inventor:
`Iwao Matsumoto, Toyonaka, Japan
`[75]
`[73] Assignee: Photo Craft Co., Ltd., Osaka, Japan
`.
`[21] App]. No.. 271’582
`[22] Filed:
`Jul. 7, 1994
`Related US. Application Data
`Continuation of Ser. No. 973,424, Nov. 9, 1992, aban-
`doned.
`
`[63]
`
`_
`_
`.
`_
`_
`Foreign Application Priority Data
`[30]
`Oct. 2, 1992 [JP]
`Japan .................................. 4-265038
`Oct. 2, 1992 [JP]
`Japan .................................. 4—265039
`6
`{3;}
`fits. ClCi
`..........................................ééé/gilg’é/g:
`
`[58] Fine or Search '21..
`"1.............. 362/26, 31
`
`[56]
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,729,068 3/1988 Ohe ....................................... 362/26
`4,811,507 3/1989 Blanchet ........
`362/31
`
`4,914,553 4/1990 Hamada et al.
`362/31
`
`5,005,108 4/1991 PristaSh et a1.
`362/26
`5,079,675 1/1992 Nakayama ............................ 362/26
`
`5,093,765
`3/1992 Kashima et a1. ...................... 362/31
`5,128,842 7/1992 Kenmochi .....
`362/31
`
`5,134,549 7/1992 Yokoyama
`362/31
`5/1993 Murase et al. ..................... 362/31
`5,207,493
`Primary Examiner—Richarcl A. Bertsch
`Assistant Examiner—M. Kocharov
`Attorney, Agent, or Firm—Webb Ziesenheim Bruening
`Logsdon Orkin & Hanson
`[57]
`ABSTRACT
`An illuminating apparatus has a transparent or semi-
`“impale” °Pt1°al medmm in the f°rm 0f an acrylic
`plate, two fluorescent tubes for emitting light into the
`acrylic plate through opposite end surfaces thereof, and
`a reflecting plate disposed under a lower surface of the
`acrylic plate for upwardly reflecting the light. The
`lower surface of the acrylic plate defines a diffusing
`plane including a plurality of irregular reflector regions
`distributed thereon. The irregular reflector regions
`°°mPrise ShiP‘ShaPe Paltterns “mged in3'1““3‘P°Siti°n
`longitudinally of the fluorescent tubes. The diffusing
`plane further includes modified irregular reflector re-
`gions formed where the irregular reflector regions are
`absent. The modified irregular reflector regions irregu-
`larly reflect a less quantity of light than the irregular
`reflector regions.
`
`19 Claims, 9 Drawing Sheets
`
`
`
`10
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`k
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`LG D_00 1 332
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`LG Display Ex. 1010
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`LGD_001332
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`LG Display Ex. 1010
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`

`

`US. Patent
`
`Jan. 31, 1995
`
`Sheet 1 of 9
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`5,386,347
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` TGE
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`LGD 001333
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`LGD_001333
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`US. Patent
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`Jan. 31, 1995
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`Sheet 2 of 9
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`5,386,347
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`LGD_001334
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`LGD_001334
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`. US. Patent
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`Jan. 31, 1995
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`Sheet 3 of 9
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`5,386,347
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`F! (3.3
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`(A)
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`FIG.3
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`(B)
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`8
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`A
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`10
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`9
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`10
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`10
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`8
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`\\
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`\\
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`LGD_001335
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`LGD_001335
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`US. Patent
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`Jan. 31, 1995
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`Sheet 4 of 9
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`5,386,347
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`FIG.4
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`LGD_001336
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`LGD_001336
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`US. Patent
`
`Jan. 31, 1995
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`Sheet 5 of 9
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`5,386,347
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` mdi
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`LGD 001337
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`LGD_001337
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`US. Patent
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`Jan. 31, 1995
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`Sheet 6 of 9
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`5,386,347
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`910
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`A
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`8
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`‘
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`A
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`LGD_001338
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`LGD_001338
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`US. Patent
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`Jan. 31, 1995
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`Sheet 7 of 9
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`5,386,347
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`FIGS
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`'9 14
`
`14
`
`10
`
`u.
`
`8
`
`\ ////z/"///////Wfl/AIM/I, /
`
`k
`
`Fl GJO
`
`////////xxx/m /
`
`A.
`
`FIG.“
`
`10
`Vl/W‘W’W’VI/WV/VI
`
`98
`/
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`LGD_001339
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`LGD_001339
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`US. Patent
`
`Jan. 31, 1995
`
`Sheet 8 of 9
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`5,386,347
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`PIC-3.12
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`LGD_001340
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`LGD_001340
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`

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`US. Patent
`
`Jan. 31, 1995
`
`Sheet 9 of 9
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`5,386,347
`
`ART)
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`Fth.13(PRlOR
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`LGD_001341
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`LGD_001341
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`

`

`1
`
`5,386,347
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`ILLUMINATING APPARATUS AND A METHOD
`OF MANUFACTURING AN EDGE LIGHT
`CONDUCTOR FOR USE TI-IEREIN
`
`This is a continuation of copending application Ser.
`No. 07/973,424 filed on Nov. 9, 1992 now abandoned.
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`
`5
`
`10
`
`15
`
`20
`
`This invention relates to an illuminating apparatus
`and a method of manufacturing an edge light conductor
`for use therein. More particularly, the invention relates
`to an illuminating apparatus comprising an edge light
`conductor including a plate of transparent or semitrans-
`parent optical medium, and light sources opposed to
`end surfaces of the plate for introducing light inwardly
`of the plate through the end surfaces. The plate has at
`least one of front and back surfaces defining a diffusing
`plane including irregular reflector regions distributed
`over the diffusing plane. The invention relates also to a
`method of manufacturing the edge light conductor.
`2. Description of the Related Art
`This type of illuminating apparatus has a construction
`as shown in FIG. 12. A plate of transparent or semi-
`transparent optical medium receives light beams b1, b2,
`b3 and b4 entering through an end surface 2. The plate
`A has a lower surface defining a diffusing plane 8 in-
`cluding irregular reflector regions 9a and 9b. The beams
`bl and b2 are irregularly reflected from the irregular
`reflector regions 9a and 9b to exit the plate A to illumi-
`nate an object.
`Light beams, e.g. beams b3 and b4, which do not hit
`the irregular reflector regions 9 impinge on the upper
`and lower surfaces of the plate A at incident angles 9
`not exceeding a critical angle 0c, to be totally reflected.
`The incident angles are dependent on the angles at
`which the beams impinge on the end surface 2 and on
`the thickness of the plate A. As a result, these beams b3
`and b4 continue traveling inside the plate A, instead of 40
`exiting the plate A, before reaching the irregular reflec-
`tor regions 9.
`The quantity of exiting light (i.e. illuminating inten-
`sity) per unit area of an illuminating plane of the illumi-
`nating apparatus is adjustable by varying areas of the
`irregular reflector regions per unit area of the diffusing
`plane 8.
`The irregular. reflector region 9b remote from the end
`surface 2 has a large irradiated area per unit source area
`because of a long distance from the light source L. In
`addition, the beam b2 reaches this irregular reflector
`region 9b after being considerably attenuated as it trav-
`els along an extended optical path through the plate A.
`Thus, the beam b2 impinges on a unit area of the irregu-
`lar reflector region 9b in a smaller quantity than the
`beam bl impinging on the unit area of the irregular
`reflector region 9:: close to the end surface 2. Naturally,
`therefore, the irregular reflector region 9b provides a
`reduced quantity of irregular reflection per unit area.
`In order for the illuminating apparatus to have a
`uniform illuminating intensity throughout the illuminat-
`ing plane, the quantity of irregular reflection must be
`uniformed throughout unit areas of the diffusing plane
`8
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`25
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`30
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`35
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`45
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`50
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`55
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`A plate A in a conventional illuminating apparatus of 65
`this defines a diffusing plane 8 including irregular re-
`flector regions 9 as shown in FIG. 13. The irregular
`reflector regions 9 are distributed such that the areas
`
`LGD_001342
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`2
`thereof occupying unit areas of the diffusing plane 8 are
`larger in positions 8b remote from end surfaces 2 of the
`plate A than in positions 8a close thereto.
`According to the prior art noted above, it is necessary
`to secure large regions 13 of the diffusing plane 8 in the
`positions 8a close to the end surfaces 2 where no irregu-
`lar reflector regions 9 are formed,
`in order that the
`irregular reflector regions 9 are larger in the positions
`8b remote from the end surfaces 2 than the positions 8a
`close thereto. These regions 13 are left to be smooth and
`transparent regions producing little or no effect of irreg-
`ular reflection.
`
`Thus, the diffusing plane 8 produces the less total
`quantity of irregular reflection for the regions 13 where
`no irregular reflector regions 9 are formed. This results
`in the inconvenience that the illuminating apparatus
`becomes dark with the illuminating intensity reduced
`for uniformity. The conventional construction also has
`a disadvantage of failing to use the light from the light
`sources effectively.
`In the prior art, the quantity of irregular reflection
`per unit area is adjusted by means of the irregular reflec-
`tor regions and transparent regions. This inevitably
`results in lack of uniformity in illuminating intensity
`over the illuminating plane of the apparatus since the
`irregular reflector regions and transparent regions pro-
`duce a great difference in illuminating intensity (con-
`trast). Specifically, the patterns of the irregular reflector
`regions 9 distributed as shown in FIG. 13 appear on the
`illuminating plane of the apparatus.
`
`SUMMARY OF THE INVENTION
`
`The object of the present invention is to eliminate the
`disadvantages of the prior art noted above.
`This object is fulfilled, according to the present in-
`vention, by an illuminating apparatus as noted in the
`outset hereof, in which the diffusing plane further in-
`cludes modified irregular reflector regions formed in at
`least some of the parts thereof from which the irregular
`reflector regions are absent, the modified irregular re-
`flector regions providing a less quantity of irregular
`reflection than the irregular reflector regions.
`With the above construction in which modified irreg-
`ular reflector regions are formed in the pans of the
`diffusing plane having no irregular reflector regions, the
`quantity of irregular reflection per unit area of the dif-
`fusing plane may be adjusted by varying a ratio between
`the irregular reflector regions and modified irregular
`reflector regions occupying the unit areas of the diffus-
`ing plane. At the same time, the light emitted from light
`sources is irregularly reflected by the modified irregular
`reflector regions also.
`Since the modified irregular reflector regions also
`reflect the light traveling from the light sources, the
`illuminating intensity on the illuminating plane of the
`apparatus may be increased while the intensity per unit
`area of the illuminating plane is adjustable. The quantity
`of irregular reflection per unit area is adjusted by means
`of the irregular reflector regions and modified irregular
`reflector regions. The irregular reflector regions and
`modified irregular reflector regions have a smaller dif-
`ference in illuminating intensity (contrast) than the ir-
`regular reflector regions and transparent regions. Thus,
`the quantity of irregular reflection may be adjusted with
`subtle variations
`in illuminating intensity. Conse-
`quently, the irregular reflector regions distributed over
`the diffusing plane are invisible on the illuminating
`plane of the apparatus.
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`LGD_001342
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`

`3
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`5,386,347
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`4
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`Thus, the illuminating apparatus according to the
`present invention provides increased brightness and
`minimal unevenness in illuminating intensity , on the
`illuminating plane though the same light sources as in
`the prior an are used.
`In the illuminating apparatus according to the present
`invention, the irregular reflector regions may be formed
`on the diffusing plane such that a greater quantity of
`light is irregularly reflected from positions remote from
`the end surfaces than from positions close thereto.
`With this arrangement, illuminating intensity may be
`uniformed throughout the diffusing plane. This appara-
`tus provides increased brightness while uniforming
`illuminating intensity throughout the diffusing plane.
`The irregular reflector regions and modified irregular
`reflector regions may comprise rugged surfaces formed
`on the plate.
`With this construction, the irregular reflector regions
`and modified irregular reflector regions produce a
`greater effect of irregular reflection than in the prior
`art. In the prior art, the irregular reflector regions are
`formed by applying a hypochromatic white ink or
`milky paint mixed with glass beads or other diffusing
`materials, to a plate surface by a printing technique.
`In the prior art, the irregular reflector regions are
`formed by applying ink or paint to a smooth plate sur-
`face. Since an interface between plate and ink or paint
`reflects a certain quantity of light, part of the light im-
`pinging on the irregular reflector regions is reflected by
`the interface to return inwardly of the plate without
`reaching the ink or paint. Consequently, a reduced
`quantity of light is irregularly reflected by the irregular
`reflector regions. The part of light reaching the ink or
`paint is attenuated through repeated irregular reflec—
`tions within the layer of ink or paint. Further, the irreg-
`ularly reflected light exiting the ink or paint may be '
`blocked by pigments or diffuser particles present on
`optical paths. The effect of irregular reflection is im-
`paired in this way. However, such an inconvenience is
`eliminated where the irregular reflector regions and
`modified irregular reflector regions are in the form of
`rugged surfaces, thereby to enhance the effect of irregu-
`lar reflection.
`‘
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
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`Consequently, the illuminating apparatus according
`to the present invention provides increased brightness
`with the enhanced effect of irregular reflection pro-
`duced by the irregular reflector regions and modified
`irregular reflector regions.
`In a further aspect of the invention, a method of man-
`ufacturing an edge light conductor is provided which
`comprises the steps of shaping at least one of front and
`back surfaces of a plate of transparent or semitranspar-
`ent optical medium to be a uniform rugged surface
`substantially throughout an entirety thereof, and form-
`ing modified irregular reflector regions by applying
`deposits to part of the rugged surface to limit a quantity
`of irregular reflection.
`With this method, there is no need to form graphic
`patterns of the irregular reflector regions with great
`subtlety and ultra—high precision in the process of form-
`ing the rugged surface. The parts having the deposits
`act as the modified irregular reflector regions.
`Thus, the present invention provides a method of
`easily and quickly manufacturing an edge light conduc-
`tor having a high efficiency of irregular reflection and
`assuring bright edge light.
`The parts having the deposits to act as the modified
`irregular reflector regions may retain a certain quantity
`
`45
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`50
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`60
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`65
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`of irregular reflection caused by the rugged surface
`lying underneath the deposits. With this arrangement,
`the modified irregular reflector regions may cause ir~
`regular reflection while the illuminating intensity of the
`edge light is adjustable by a distribution ratio between
`the irregular reflector regions and modified irregular
`reflector regions. Thus, the edge light conductor manu-
`factured by this method provides an increased total
`quantity of irregular reflection to assure brightness.
`The rugged surface may advantageously be formed
`by sand blasting.
`In this way, the rugged surface may be formed sub-
`stantially uniformly, simply and quickly over the entire
`or approximately entire surface of the plate for defining
`the irregular reflector regions.
`The modified irregular reflector regions may be
`formed by applying transparent ink in a printing process
`to form the deposits.
`With this method, the transparent ink applied to the
`rugged surface produces the same effect as water adher-
`ing to ground glass, to limit the quantity of irregular
`reflection from the rugged surface. Since transparent
`ink is applied by printing, very fine and accurate
`graphic patterns of the irregular reflector regions may
`be formed simply and quickly. Thus, this method is
`capable of simply and quickly manufacturing an edge
`light conductor that provides a precisely regulated illu-
`minating intensity.
`The transparent ink may be applied by a printing
`technique such as photographic printing using a photo-
`resist or by silk screen printing, for example. Then, the
`transparent ink applied has an unsmooth surface as dis-
`tinct from a smooth surface formed by a mirror die or
`mirror roller. In the case of silk screen printing, the
`surfaces of the transparent ink deposits have fine traces
`left by silk screen meshes, thereby defining rugged sur-
`faces for causing a certain quantity of irregular reflec-
`tion.
`
`Thus, the modified irregular reflector regions may be
`formed simply by applying the transparent ink in a
`printing process.
`Other features and advantages of the invention will
`be apparent from the following more particular descrip-
`tion of preferred embodiments of the invention, as illus-
`trated in the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a view in vertical section of an ultra-thin
`light box according to the present invention,
`FIG. 2 is a perspective view showing a diffusing
`plane of a plate mounted in the light box,
`FIGS. 3 (A) and (B) are sectional views showing a
`method of forming the diffusing plane,
`FIG. 4 is a perspective view showing a diffusing
`plane in another embodiment,
`FIG. 5 is a perspective view showing a diffusing
`plane in a further embodiment,
`FIG. 6 a fragmentary sectional view of an illuminat-
`ing apparatus in a still further embodiment,
`FIG. 7 a fragmentary sectional view of an illuminat-
`ing apparatus in a still further embodiment,
`FIG. 8 a fragmentary sectional view of an illuminat-
`ing apparatus in a still further embodiment,
`FIG. 9 is an enlarged view showing a deposit on a
`plate in a still further embodiment,
`FIG. 10 is an enlarged view showing a deposit on a
`plate in a still further embodiment,
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`LGD_001343
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`5,386,347
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`FIG. 11 is an enlarged view showing a deposit on a
`plate in a still further embodiment,
`FIG. 12 is a schematic view showing functions of a
`diffusing plane of a plate, and
`FIG. 13 is a perspective view showing a diffusing
`plane of a conventional apparatus.
`
`6
`high precision. The diffusing plane 8 further includes
`modified irregular reflector regions 10 formed where
`the irregular reflector regions 9 are absent. The modi-
`fied irregular reflector regions 10 irregularly reflect a
`less quantity of light than the irregular reflector regions
`9.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`Illuminating apparatus according to the present in-
`vention will be described in detail with reference to the
`drawings.
`FIG. 1 shows an edge light type ultra-thin light box in
`one embodiment of the present invention.
`This ultra-thin light box comprises a casing P having
`an upper surface defining an illuminating plane. A posi-
`tive photograph or film such as a slide photograph may
`be placed on the illuminating plane for observation by
`means of transmitted light.
`A milky, semitransparent acrylic plate 1 is mounted
`on the illuminating plane of the casing P to act as an
`edge light conductor. Light emitted from the illuminat-
`ing plane has a color temperature adjustable to 5,000
`degrees, for example.
`The casing P contains a transparent or semitranspar-
`ent optical medium in the form of an acrylic plate A,
`two fluorescent tubes L acting as light sources for emit-
`ting light into the acrylic plate A through opposite end
`surfaces 2 thereof, and a circuit device 3 for lighting the
`fluorescent tubes L.
`
`The fluorescent tubes L may be the cold cathode type
`or hot cathode type.
`A battery 5 is connected to an outer position of the
`casing P through a pin jack 4 to supply power to the
`fluorescent tubes L.
`Power may be derived also from a household AC
`outlet by using an AC adapter connected through the
`pin jack 4.
`Each of the fluorescent tubes L has a reflector 6
`attached thereto, whereby light emitted from each fluo-
`rescent tube L is all directed to the end surface 2 of the
`acrylic plate A. A reflecting plate 7 is disposed opposite
`a lower surface of the acrylic plate A. The reflecting
`plate 7 has an upper surface defining a mirror surface,
`whereby light emerging from the lower surface of the
`acrylic plate A is reflected toward the upper surface
`thereof. The acrylic plate A is disposed directly under
`the illuminating plane, and the lower surface of the
`acrylic plate A defines a diffusing plane 8.
`FIG. 2 shows the fluorescent tubes L and acrylic
`plate A, with the diffusing plane 8 revealed. The diffus-
`ing plane 8 includes a plurality of irregular reflector
`regions 9 distributed thereon.
`The irregular reflector regions 9 comprise ship-shape
`patterns arranged in juxtaposition. The ship-shape pat~
`terns are elongated toward the fluorescent tubes L, and
`arranged side by side in the longitudinal direction of the
`fluorescent tubes L substantially throughout the diffus-
`ing plane 8.
`Thus, the irregular reflector regions 9 are formed
`such that a greater quantity of light is irregularly re-
`flected in positions 8b remote from the end surfaces 2
`than in positions 8a close thereto.
`For clarity of illustration, FIG. 2 shows the ship-
`shape patterns forming the irregular reflector regions 9
`as considerably enlarged in relation to the entire illumi-
`nating apparatus. In fact, these patterns are formed very
`narrow, very large in number, and finished with ultra-
`
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`In this embodiment, the modified irregular reflector
`regions 10 fill the entire area of the diffusing plane 8 in
`which the irregular reflector regions 9 are not formed.
`The irregular reflector regions 9 and modified irregular
`reflector regions 10 comprise rugged surfaces formed
`on the acrylic plate A.
`It is also possible to form the irregular reflector re-
`gions 9 and modified irregular reflector regions 10 by
`applying a hypochromatic white ink or milky paint
`mixed with glass beads or other diffusing materials, to a
`surface of a plate by a printing technique as described
`later.
`
`The above-noted rugged surfaces may be formed by
`various methods such as injection molding, die casting
`such as solven casting, cutting, etching, electric dis-
`charge machining, photographic printing using a photo-
`resist or an ultraviolet hardenable substance, and sand
`blasting described hereinafter.
`In this embodiment, the rugged surfaces are formed
`as follows.
`
`An acrylic plate having smooth surfaces providing
`almost no irregular reflection (such a plate is readily
`available in commerce) is cut to size, and the end sur-
`faces 2 are formed to define smooth planes for receiving
`light from the light sources.
`One of the upper and lower surfaces of the acrylic
`plate A is used to define the diffusing plane 8. First, as
`shown in FIG. 3 (A), a rugged surface is formed over
`the entire diffusing plane 8 by sand blasting. This rug-
`ged surface has a degree of roughness adjustable by
`selecting size, blasting intensity, blasting time and the
`like of an abrasive used in the sand blasting.
`In fact, what is known as a diffuser plate or diffuser
`sheet having such a rugged surface already formed is
`commercially available also. Such a product may be
`used instead.
`
`Next, as shown in FIG. 3 (B), an acrylic transparent
`ink is applied by silk screen printing technique to por-
`tions of the rugged surface for forming the modified
`irregular reflector regions 10. This ink forms deposits to
`limit
`irregular
`reflection. The ship-shape patterns
`shown in FIG. 2 are left free of the ink deposits.
`The transparent ink may be applied to the modified
`irregular reflector regions 10 by other printing tech-
`niques than silk screening. For example, a photoresist
`polymer may be applied in buildup form.
`The transparent ink produces the same effect as water
`adhering to ground glass, to reduce irregular reflection
`from the rugged surface.
`In this embodiment, as noted above, the transparent
`ink is applied to the modified irregular reflector regions
`10 by silk screen printing. The surfaces of the transpar-
`ent ink deposits have traces left by silk screen meshes,
`thereby defining rugged surfaces with a certain degree
`of roughness. In addition, the original, rugged surface
`lies underneath the ink deposits. The portions of the
`lower surface 8 of the acrylic plate A to which the
`transparent ink has been applied, therefore, cause irreg-
`ular reflection in an appropriate degree, instead of elimi-
`nating the irregular reflection altogether. Thus, these
`portions provide the modified irregular reflector re-
`gions 10.
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`7
`The portions of the rugged surface remaining in the
`ship-shape patterns, as they are, act as the irregular
`reflector regions 9.
`The quantity of irregular reflection from the modified
`irregular reflector regions 10 is adjustable by varying
`the degree of roughness of the transparent ink surfaces
`or by mixing an irregularly reflecting additive into the
`transparent ink.
`The illuminating apparatus in this embodiment, as
`constructed above, has shown an improvement in illu-
`minating intensity of about 40—50% over a conventional
`illuminating apparatus without the modified irregular
`reflector regions 10. In the conventional illuminating
`apparatus, the irregular reflector regions distributed
`over the illuminating plane are clearly discernible in the
`naked eye. By contrast, the illuminating apparatus in
`this embodiment provides a substantially uniform inten-
`sity of illumination, with no visible variation, through-
`out the illuminating plane.
`The irregular reflector regions 9 are not limited to the
`ship-shape patterns, but may be in the form of triangles,
`groups of lines, or dots.
`Other embodiments will be described next.
`FIGS. 4 and 5 show reflector regions formed of dot
`patterns. The diffusing plane 8 shown in FIG. 4 includes
`irregular reflector regions 9 formed of a plurality of
`dots having different sizes. These dots are the smaller
`toward the end surfaces 2 and the larger away there-
`from.
`
`The diffusing plane 8 shown in FIG. 5 includes a
`plurality of dots having different sizes and formed in
`portions other than the irregular reflector regions 9.
`These dots provide the modified irregular reflector
`regions 10, which are the larger toward the end surfaces
`2 and the smaller away therefrom.
`Thus, the irregular reflector regions 9 in FIGS. 4 and
`5 are arranged such that light is irregularly reflected in
`a greater quantity in positions 8b of the diffusing plane
`8 remote from the end surfaces 2 than in positions 8a
`thereof close to the end surfaces 2.
`The irregular reflector regions 9 are not limited to the
`function to uniform the illuminating intensity on the
`illuminating plane of the light box, but may be adapted
`to vary the intensity for certain parts of the illuminating
`plane.
`The modified irregular reflector regions 10 may be
`formed in only certain of the parts of the diffusing plane
`8 where the irregular reflector regions 9 are not formed.
`The quantity of irregular reflection from the modified
`irregular reflector regions 10 need not be uniform
`through the diffusing plane 8. Plural types of modified
`irregular reflector regions 10 providing varied quanti-
`ties of irregular reflection may be distributed over the
`diffusing plane 8.
`The diffusing plane 8 may be formed on each of the
`upper and lower surfaces of the acrylic plate A.
`The light box may include a plurality of acrylic plates
`A as shown in FIGS. 6, 7 and 8.
`As shown in FIG. 7, the light box may further include
`an irregular reflector plate 11 disposed under the acrylic
`plates A and defining an irregularly reflecting ragged
`surface 11a.
`
`As shown in FIG. 8, the bottom acrylic plate A may
`have an upper surface defining the diffusing plane 8 and
`a lower surface defining an irregularly reflecting rug-
`ged surface 12.
`The illuminating apparatus is not limited to the ultra-
`thin light box, but may comprise a backlight apparatus
`
`65
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`LGD_001345
`
`5,386,347
`
`5
`
`10
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`15
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`20
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`25
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`30
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`35
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`4O
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`45
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`50
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`55
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`8
`for a display device or for a liquid crystal display of an
`office automation product, for example.
`FIGS. 9, 10 and 11 show, in enlargement, the modi-
`fied irregular reflector regions 10 having transparent
`ink deposits. As shown in FIG. 9, the modified irregular
`reflector regions 10 may include bubbles 14 formed in
`recesses of the rugged surface as a result of incomplete
`filling with the transparent ink.
`As shown in FIG. 10, the modified irregular reflector
`regions 10 may have rugged surfaces 10:: formed by
`deposits to produce irregular reflection.
`As shown in FIG. 11, the modified irregular reflector
`regions 10 may be formed of a thin layer of transparent
`ink through which ridges of the rugged surface project
`to a certain extent.
`
`The deposits defining the modified irregular reflector
`regions 10 may be formed of any other material than the
`acrylic transparent ink, as long as it is effective to re-
`duce irregular reflection. For example, a material in
`sheet form may be used, or a chemical may be used to
`dissolve the ridges of the rugged surface for smooth-
`ness.
`
`The method of forming the modified irregular reflec-
`tor regions 10 is not limited to the uniform application
`of transparent ink to the lower surface 8. The type of
`ink, the method or mode of application may be varied as
`appropriate, to form plural types of modified irregular
`reflector regions having different quantities of irregular
`reflection and distributed over the lower surface 8.
`As noted in the first embodiment, the irregular reflec-
`tor regions 9 are not limited to the ship-shape patterns,
`but may be in the form of triangles, groups of lines, or
`dots.
`
`The plate of transparent or semitransparent optical
`medium is not limited to the acrylic plate A. Glass or
`various plastics (e.g. polyethylene, polyester and epoxy
`resin) may be employed instead.
`What is claimed is:
`
`1. An illuminating apparatus comprising:
`an edge light conductor including plate means of
`transparent or semitransparent Optical medium
`having end surfaces and at least one of front and
`back surfaces defining a diffusing plane, said diffus-
`ing plane including irregular reflector regions dis-
`tributed over a portion of said diffusing plane, said
`diffusing plane further including modified irregular
`reflector regions formed in a remainder of said
`diffusing plane, with said modified irregular reflec-
`tor regions providing a lesser quantity of irregular
`reflection than said irregular reflector regions, with
`said irregular reflector regions formed on said dif-
`fusing plane such that a greater quantity of light is
`irregularly reflected from positions remote from
`said end surfaces than from positions close thereto
`and with said irregular reflector regions and said
`modified irregular reflector regions including rug-
`ged surfaces formed on said plate means; and
`light sources opposed to said end surfaces of said
`plate means for introducing light inwardly of said
`plate means through said end surfaces.
`2. An illuminating apparatus as defined in claim 1,
`wherein said plate means includes an acrylic plate.
`3. An illuminating apparatus as defined in claim 1,
`wherein said irregular reflector regions comprise a plu-
`rality of ship-shape patterns elongated toward said light
`sources and arranged side by side in a longitudinal di-
`rection of said light sources substantially throughout
`said diffusing plane.
`
`LGD_001345
`
`

`

`5,386,347
`
`10
`an edge light conductor including plate means of
`transparent or semitransparent optical medium
`having end surfaces and at least one of front and
`back surfaces defining a diffusing plane, said diffus-
`ing plane including irregular reflector regions dis-
`tributed over a portion of said diffusing plane, said
`diffusing plane further including modified irregular
`reflector regions formed in a remainder of said
`diffusing plane, with said modified irregular reflec-
`tor regions providing a lesser quantity of irregular
`reflection than said irregular reflector regions; and
`light sources opposed to said end surfaces of said
`plate means for introducing light inwardly of said
`plate means through said end surfaces.
`16. An illuminating apparatus as defined in claim 15,
`wherein said modified irregular reflector regions in-
`clude rugged surfaces formed on said plate means with
`deposits attached to said rugged surfaces.
`17. The illuminating apparatus as defined in claim 16,
`wherein said deposits include transparent ink applied to
`said rugged surfaces.
`.
`18. The illuminating apparatus as defined in claim 16,
`wherein each said deposit has a non-smooth upper sur-
`face.
`
`19. An illuminating apparatus comprising:
`an edge light conductor including plate means of
`transparent or semi-transparent optical medium
`having end surfaces, at least one other surface de-
`fining a defusing plane, irregular reflector regions
`distributed over a portion of said diffusing plane,
`wherein said irregular reflector regions include
`rugged surfaces formed on said plate means, modi-
`fied irregular reflector regions formed on said plate
`means in parts thereof from which said irregular
`reflector regions are absent, wherein said modified
`irregular reflector regions include rugged surfaces
`formed on said plate means with deposits attached
`to said rugged surfaces, and wherein said modified
`irregular reflector regions provide a lesser quantity
`of irregular reflection than said irregular reflector
`regions; and
`light sources opposed to said end surfaces of said
`plate means for introducing light inwardly of said
`plate means through said end surfaces.
`*
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`t
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`9
`4. An illuminating apparatus as defin