United States Patent [191
`Nakayama et a].
`
`[54] LIQUID CRYSTAL DISPLAY DEVICE
`HAVING A REMOVABLE HOLDING
`MEMBER FOR THE LIGHT SOURCE
`
`[75] Inventors: Tatsuya Nakayama; Takanori Takaki;
`Seiki Takahashi; Toshio Tobita, all of
`Kumamoto, Japan
`
`[73] Assignees: Mitsubishi Denki Kabushiki Kaisha;
`Asahi Glass Company Ltd., both of
`Tokyo, Japan
`
`[21] Appl. No.: 365,791
`[22] Filed:
`Dec. 29, 1994
`[30]
`Foreign Application Priority Data
`
`May 18, 1994
`
`[JP]
`
`Japan .................................. .. 6-103797
`
`[51] rm. (:1.6 ..................... .. G02F 1/1333; G02F 1/1335;
`GOlD 11/28; F21V 7/04
`[52] U8. c1. ............................... .. 349/58; 349/64; 349/65;
`345/905; 362/26; 362127; 362/31; 385/901
`[58] Field of Search ................................ .. 362/26, 27, 31,
`362/32; 359/40, 41, 42, 4s, 50, 49, 69,
`70, 83; 385/146, 901; 345/905; 349/53,
`61, 62, 64, 65, 70, 113
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`8/1977 Eberhardt et a1. ...................... .. 359/42
`4,043,636
`4,560,264 12/1985 Kitazawa et al. .... ..
`359/83
`4,573,766
`3/1986 Bournay, J1: et a1. .................. .. 359/48
`
`3a
`
`USOO5654779A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,654,779
`Aug. 5, 1997
`
`4,945,350 7/1990 Kawamura . . . . . .
`
`6/1992 Miyadera
`5,121,232
`7/1992 Ohno et a1. .
`5,128,781
`5,166,815 11/1992 Elder?eld
`5,182,660
`1/1993 Tanaka .......... ..
`5,438,484
`8/1995 Kanda et a1.
`5,453,855
`9/1995 Nakamura et a1.
`
`5,473,454 12/1995 Blanchard . . . . . . .
`5,542,016 7/1996 Kaschke .... ..
`5,555,160
`9/1996 Tawara et a1. ..
`
`. . . . . . . .. 359/50
`
`359/49
`362/26
`359/49
`359/50
`385/95
`359/83
`
`. . . .. 359/69
`385/901
`362/31
`
`FOREIGN PATENT DOCUMENTS
`
`3208-162 10/1982 Gennany ............................... .. 362/31
`62-35390 3/1987 Japan.
`63-150985 lO/1988 Japan.
`4-102888 4/1992 Japan.
`4-186226 7/1992 Japan ..................................... .. 359/48
`
`Primary Examiner-William L. Sikes
`Assistant Examiner—-Walter J. Malinowski
`Attorney, Agent, or Firm-—Leydig, Voit & Mayer
`[57]
`ABSTRACT
`A liquid crystal display device adaptable for various appli
`cations is provided which comprises a liquid crystal display
`panel, lamps, lamp holders respectively holding the lamps,
`a photoconduclive board provided between the lamps, and a
`frame covering both the lamps and the lamp holders,
`wherein the photoconductive board comprises an outer
`photoconductive part ?xed to the lamp holders, and an inner
`photoconductive part held on the rear side thereof by a
`holding member provided to the frame.
`
`11 Claims, 9 Drawing Sheets
`
`2
`
`4a 1a
`
`3b
`
`10D
`lb
`
`C
`4b
`12,13
`
`LG Display Ex. 1009
`
`LGD_001317
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 1 of 9
`
`5,654,779
`
`F I6. 121
`
`4a
`
`27
`
`2
`
`4a 1a
`
`3b
`SD
`10b
`1b
`
`12,13
`
`1a
`
`3a
`M
`A{
`
`10a
`55a
`
`LGD_001318
`
`

`
`U.S. Patent
`
`Aug. 5, 1997
`
`Sheet 2 of 9
`
`5,654,779
`
`F I G. 2a
`
`48
`
`LGD_0O1319
`
`LGD_001319
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 3 of 9
`
`.
`
`5,654,779
`
`F l 6. 3a
`
`FIG. 3b
`
`90
`
`15a p
`
`LGD_001320
`
`

`
`U.S. Patent
`
`Aug. 5, 1997
`
`Sheet 4 of9
`
`5,654,779
`
`F I G. 4a
`
`5a
`
`4a
`
`2
`
`1b
`
`19
`
`4b
`
`F I G. 4b
`
`1b
`
`19
`
`LGD_OO1321
`
`LGD_001321
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 5 of 9
`
`5,654,779
`
`FIG. 5
`
`LGD_001322
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 6 of 9
`
`5,654,779
`
`FlG.7a
`
`3b
`
`K
`
`A
`
`“10b
`;
`14b 15a “1
`
`LGD_001323
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 7 of 9
`
`5,654,779
`
`my?
`
`’
`
`l_::
`
`BbL 21
`EE
`
`‘ID; ,
`
`"'
`
`ii Jab
`:2 we
`
`LGD_001324
`
`

`
`US. Patent
`
`Aug. 5, 1997
`
`Sheet 8 of 9
`
`5,654,779
`
`FIG.9a
`
`A?
`9
`5
`
`r/ H
`
`@//@z
`w
`w
`46
`12.13
`
`v
`4
`
`LGD_001325
`
`

`
`U.S. Patent
`
`Aug. 5, 1997
`
`Sheet 9 0f 9
`
`5,654,779
`
`F I G. 1O PRIOR ART
`
`F | G. .HPRIORART
`
`3a
`
`{
`{
`
`3a
`
`LVg
`4%;
`l/li7fl/9jf/l/l/I/l/
`7
`58
`
`100
`
`11
`
`LGD_001326
`
`

`
`5,654,779
`
`1
`LIQUID CRYSTAL DISPLAY DEVICE
`HAVING A REMOVABLE HOLDING
`MEMBER FOR THE LIGHT SOURCE
`
`2
`to illuminate the liquid crystal display panel 2, resulting in
`insufficient utilization of light
`Still further, since the light guiding board 4 is relatively
`heavy, it is di?icult to position the board 4 precisely during
`its mounting, and signi?cant labor is needed for handling the
`board 4.
`
`SUMMARY OF THE INVENTION
`
`The present invention has been made to overcome the
`foregoing problems of the prior art.
`It is an object of the present invention to provide a liquid
`crystal display device wherein at least a part of the light
`guiding board can be removed ?om the lighting unit section
`or lighting means can be removed ?om the liquid crystal
`display panel section without removing the frames and
`Without the need of varying the outer dimensions and
`thickness of the device.
`It is another object of the present invention to provide a
`liquid crystal display device that utilizes light with higher
`e?iciency.
`It is a yet object of the present invention to provide a
`liquid crystal display device having lighter weight remov
`able portions.
`According to a ?rst aspect of the present invention, there
`is provided a liquid crystal display device comprising a
`liquid crystal display panel, lamps, lamp holders respec
`tively holding the lamps, a light guiding board provided
`between the lamps, and a frame covering both the lamps and
`the lamp holders wherein the light guiding board comprises
`an outer light guiding part ?xed to the lamp holders, and an
`inner light guiding part held on the rear side by a holding
`member mounted on the ?ame.
`According to a second aspect of the present invention,
`there is provided a liquid crystal display device comprising
`a liquid crystal display panel, lamps, lamp holders respec
`tively holding the lamps, a light guiding board provided
`between the lamps, and a ?ame covering both the lamps and
`the lamp holders wherein the light guiding board comprises
`an outer light guiding part ?xed to the lamp holders and an
`inner light guiding part held on the rear side by a holding
`member mounted on the ?ame, and the inner light guiding
`part has on the front side a surface inclined ?om the opposite
`side edges toward the center.
`According to a third aspect of the present invention, there
`is provided a liquid crystal display device comprising a
`liquid crystal display panel, lamps, lamp holders, a light
`guiding board, and a ?ame holding both the lamps and the
`lamp holders wherein the’ ?ame comprises a ?ontal frame
`part covering the ?ont side of the lamps and lamp holders
`and a rear ?ame part supporting the rear side of the light
`guiding board as well as the lamps and lamp holders by
`means of a holding member, and the rear frame part is
`disposed outside the opposite side edges of the light guiding
`board that adjoin the respective lamps while an edge of the
`rear ?ame part closest to each of the opposite side edges of
`the light guiding board is outwardly spaced from the light
`guiding board.
`According to a fourth aspect of the present invention,
`there is provided a liquid crystal display device comprising
`a liquid crystal display panel, a ?ame holding the panel, and
`a light guiding board containing a lamp, wherein the light
`guiding board is held on the rear side by means of a holding
`member mounted on the ?ame.
`With the liquid crystal display device according to the ?rst
`aspect of the present invention, the inner light guiding part
`
`BACKGROUND OF THE INVENTION
`The present invention relates to thin liquid crystal display
`devices.
`Typically, a liquid crystal display device 5 includes a
`liquid crystal display panel in which an opposing pair of
`substrates sandwiches a display material such as a liquid
`crystal, a circuit board for driving the display panel, an edge
`lighting unit disposed behind the display panel, and a frame
`covering these components. The edge lighting unit includes
`a light guiding board, a lamp disposed on each lateral side
`of the board, and a holder for holding each lamp. Conven
`tional liquid crystal display devices are shown in FIGS. 10
`and 11 and include frames 1a and 1b, a liquid crystal display
`panel 2, circuit boards 3a and 3b, a light guiding board 4,
`lamps 5a and 5b, lamp holders 10a and 10b, and a lamp
`housing 11.
`As shown in FIG. 10, one conventional liquid crystal
`display device includes a light guiding board 4 comprising
`one board on respective lateral sides of which are disposed
`the lamps 5a and 5b and lamp holders 10a and 10b for
`holding the corresponding lamps 5a and 5b, and outer
`frames 1a and 1b that sandwich and cover these
`components, together with a liquid crystal display panel 2
`and circuit boards 3a and 3b. Alternatively, as shown in FIG.
`11, another conventional liquid crystal display device
`includes separably assembled, using a fastening member
`100 such as a screw, a lighting unit A including a lamp
`housing 11 for holding a light guiding board 4 and lamps 5a
`and 5b and a liquid crystal display panel section B including
`a liquid crystal display panel 2, circuit boards 3a and 3b, and
`outer ?ames 1a and 1b that sandwich and hold the panel 2
`and circuit boards 3a and 3b.
`When a liquid crystal display device is used in individual
`display devices, such as an OHP (Over Head Projector) and
`personal computer, the lighting means needs to be replaced
`with a suitable one. However, in conventional liquid crystal
`display devices employing the described structures, the
`?ames 1a and 117 must be ?rst removed to separate the
`lighting unit section A or the light guiding board 4 from the
`liquid crystal display panel section B. This process entails
`cumbersome operations in disassembly and assembly.
`In the conventional liquid crystal display device shown in
`FIG. 10, the monolithic light guiding board 4 together with
`the liquid crystal display panel 2 and the like are covered by
`the ?ames 1a and 1b. Accordingly, to remove or mount only
`the lamps or light guiding board 4, they must be detached
`?om the lamp holders 10a and 10b after removal of the
`frames 1a and lb. This process not only is cumbersome but
`also degrades the reliability of the device since the circuit
`boards 3a and 3b are exposed in the conventional liquid
`crystal display device shown in FIG. 11, on the other hand,
`the lighting unit and the liquid crystal display panel section
`are readily separable and the problem associated with the
`other conventional device does not arise. Nevertheless, these
`sections each have an element for fastening them together,
`enlarging the dimensions of their outer forms.
`Further, with the foregoing edge light type lighting unit,
`light ?om the lamps on opposite sides of the light guiding
`board 4 propagate toward the center of the light guiding
`board 4. Only light that is de?ected upwardly, as viewed in
`the drawing, by re?ection or diffusion means (not shown) on
`the upper or lower side of the light guiding board 4 is utilized
`
`15
`
`20
`
`25
`
`35
`
`45
`
`50
`
`55
`
`65
`
`LGD_001327
`
`

`
`5,654,779
`
`4
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`3
`is held in the frame only by the holding member. Therefore,
`the removal of the holding member allows the inner light
`guiding part to be removed rearwardly easily.
`With the liquid crystal display device according to the
`second aspect of the present invention, the inner light
`guiding part is held in the frame only by the holding
`member. Therefore, the removal of the holding member
`allows the inner light guiding part to be removed rearwardly
`easily. Further, since a vacancy is provided in the inner light
`guiding part, the inner light guiding part is light weight. In
`addition, light re?ected by the inclined portion of the inner
`light guiding part is additionally utilized, resulting in
`increased light utilization e?iciency.
`With the liquid crystal display device according to the
`third aspect of the present invention, the whole light guiding
`board can be removed, thereby ensuring easy removal or
`attachment of the light guiding board, simplifying the struc
`ture of the device.
`With the liquid crystal display device according to the
`fourth aspect of the present invention, the light guiding
`board containing the lamp is removable, thereby facilitating
`removal or attachment of the lighting unit while utilizing
`light e?iciently.
`
`10
`
`15
`
`20
`
`Embodiment 1
`FIGS. 1(a) and 1(b) illustrate in section an embodiment of
`a liquid crystal display device according to the ?rst aspect of
`the present invention and wherein numerals common to FIG.
`10 denote like or corresponding parts for which descriptions
`are omitted.
`The liquid crystal display device shown includes a light
`guiding board 4 disposed between lamps 5a and 5b and
`comprising an outer light guiding part 4a serving as a frame
`portion and an inner light guiding part 4b. The inner light
`guiding part 4b is ?tted into the outer light guiding part 4a
`attached to lamp holders 10a and 10b by means of a screw
`or an adhesive. The light guiding board 4 is a transparent
`material such as an acrylic resin board.
`FIG. 2(a) is a plan View of a lighting unit section A of the
`above-mentioned device and FIG. 2(b) is a perspective view
`of the outer light guiding part 4a, taken along line 2b—2b
`of FIG. 2(a).
`As shown in FIGS. 1(a) and 2(a), the outer light guiding
`part 4a is attached to the lamp holders 10a and 10b and,
`therefore, also functions as a rigid member linking the lamp
`holders 10a and 10b on opposite sides.
`As shown in FIG. 1(a), the lower end C of a frame lb is
`located outside the lateral extent W of the inner light guiding
`part 4b. The inner light guiding part 4b is held on its lower
`side (rear side) by holding members 14a and 14b mounted
`on the frame 1b, as shown in FIG. 1(b).
`FIGS. 1(b), 3(a), 3(b), 4(a), and 4(b) show holding the
`inner light guiding part 4b in the frame 1b.
`FIG. 1(b) illustrates an arrangement wherein the inner
`light guiding part 4b is ?tted into the outer light guiding part
`4a, and the holding members 14a and 14b, which are made
`of plastic or a metal plate, are inserted between the frame 1b
`and the light guiding board 4 on opposite lateral sides to ?x
`the inner light guiding part 4b to the frame 1b with a screw
`15.
`FIGS. 3(a) and 3(b) illustrate an arrangement wherein the
`inner light guiding part 4b is ?tted into the outer light
`guiding part 4a and then pressed against it by means of a
`presser spring 18 held by a screw 15a. FIGS. 3(a) and 3(b)
`are a sectional view and a plan view, respectively.
`Further, FIGS. 4(a) and 4(b) illustrate an arrangement
`wherein the inner light guiding part 4b is ?tted into the outer
`light guiding part 4a and another type of plate spring 19 is
`inserted between the frame 1b and the light guiding board 4,
`thereby holding the inner light guiding part 4b. FIGS. 4(a)
`and 4(b) are a sectional view and a fragmentary sectional
`view, respectively.
`As in the conventional liquid crystal display device, a
`light diffusing plate 27 is located on the upper side (front
`side) of the inner light guiding part 4b so that the light of the
`lamp 5a passing through the light guiding part 4 is diffused
`and directed toward the liquid crystal display panel. Further,
`on the lower side of the inner light guiding part 4b are
`provided a light scattering processing part 12 for uniformly
`directing the light of the lamp 5a upward and a re?ector
`sheet for intensely re?ecting light upward only in a speci?ed
`pattern.
`The device of Embodiment 1 operates as follows. Of the
`light rays produced by the lamps 5a and 5b that pass through
`the outer light guiding part 4a and are incident on the inner
`light guiding part 4b, those upwardly re?ected by the light
`scattering processing part 12 and the pattern of the re?ector
`
`25
`
`35
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIGS. 1(a) and 1(b) are sectional views showing the
`structm'e of one embodiment of a liquid crystal display
`device according to the ?rst aspect of the present invention;
`FIGS. 2(a) and 2(b) are a plan view showing the structure
`of the lighting unit section of the device shown in FIG. 1(a)
`and a perspective view of the lighting unit section taken
`along line 2b——2b of FIG. 2(a), respectively;
`FIGS. 3(a) and 3(b) are a fragmentary sectional view and
`a plan view showing the structure of a holding member
`mounted on the inner light guiding part of the liquid crystal
`display device according to the ?rst aspect of the present
`invention, respectively;
`FIGS. 4(a) and 4(b) are a fragmentary sectional view and
`a cross-sectional view showing the structure of another
`example of the holding member mounted on the inner light
`guiding part of the liquid crystal display device according to
`the ?rst aspect of the present invention, respectively;
`FIG. 5 is a sectional view of the structure of one embodi
`ment of a liquid crystal display device according to the
`second aspect of the present invention;
`FIG. 6 is a sectional view of the structure of another
`embodiment of the liquid crystal display device according to
`the second aspect of the present invention;
`FIGS. 7(a) and 7(b) are sectional views of the structure of
`one embodiment of a liquid crystal display device according
`to the third aspect of the present invention;
`FIGS. 8(a) and 8(b) are a bottom view for illustrating
`holding of the light guiding board of the liquid crystal
`display device according to the third aspect of the present
`invention and a sectional view taken along 8b-8b line of
`FIG. 8(a), respectively;
`FIGS. 9(a) and 9(b) are sectional views showing the
`structure of a liquid crystal display device according to the
`fourth aspect of the present invention;
`FIG. 10 is a sectional view showing the structure of a
`conventional liquid crystal display device; and
`FIG. 11 is a sectional view showing the structure of
`another conventional liquid crystal display device.
`In all ?gures, like elements are given the same reference
`numbers.
`
`45
`
`50
`
`55
`
`65
`
`LGD_001328
`
`

`
`5,654,779
`
`5
`sheet 13 on the lower side of the inner light guiding part 4b
`are rendered uniform and applied to the liquid crystal
`display panel 2 by a di?using plate 27.
`Since the liquid crystal display device according to
`Embodiment 1 has the structure described above, it exhibits
`the following effects.
`(1) It is possible to remove the inner light guiding part 4b
`without removing the ?ame 1b by merely removing holding
`members 14a and 14b mounted on the frame 1b.
`(2) Since the outer light guiding part 40 serves as a rigid
`member connecting the lamp holders 10a and 10b, the light
`guiding board is supported with higher strength.
`Embodiment 2
`FIG. 5 is a sectional view showing the structure of one
`embodiment of a liquid crystal display device according to
`the second aspect of the present invention. Since the basic
`structure is similar to Embodiment l, descriptions of com
`mon parts are omitted.
`In the liquid crystal display device according to Embodi
`ment 2, an inner light guiding part 40 has a beveled shape so
`that the thiclmess increases ?om the opposite ends and is
`?tted into the outer light guiding member toward the center.
`The way of holding the inner light guiding part 40 within the
`?ame 1b is the same as in Embodiment l and so the
`description is omitted.
`The liquid crystal display device according to Embodi
`25
`ment 2 operates as follows. Of the light rays emitted ?om
`the lamps 5a and 5b, those passing through the inner light
`guiding part 40 and directed upward by the light scattering
`processing part 12 or re?ector sheet 13 disposed on the
`lower side of the inner light guiding part 40 and those
`passing through a vacancy 28 and re?ected upward by the
`inclined upper surface of the inner light guiding part 40 are
`added together, diifused by the diffusing plate 27, and
`applied to the liquid crystal display panel 2 as uniform light.
`The light can be rendered uniform over the entire area of the
`liquid crystal display panel 2 by adjusting the light scattering
`processing part 12 and the pattern of the re?ector sheet 13,
`taking the distribution of incident light into consideration.
`Embodiment 3
`FIG. 6 is a sectional view showing the structure of one
`embodiment of a liquid crystal display device according to
`the second aspect of the present invention. Since the basic
`structure is similar to Embodiments l and 2, descriptions of
`common parts are omitted.
`In the liquid crystal display device according to Embodi
`ment 3, an inner light guiding part 4d has a beveled shape
`so that the thickness decreases from the opposite ends and is
`?tted into the outer light guiding part 4a toward the center.
`The way of holding the inner light guiding part 4d within the
`frame 1b is the same as in Embodiment l and so the
`description is omitted.
`'
`The liquid crystal display device according to Embodi
`ment 3 operates as follows. The major part of light ?om the
`lamps 5a and 5b is re?ected downward by the inclined upper
`surface of the inner light guiding part 4d and then scattered
`or re?ected upward by the light scattering processing part 12
`or re?ector sheet 13. The light thus directed upward is
`rendered uniform and applied to the liquid crystal display
`panel 2 by the diffusing plate 27 disposed above. The light
`can be rendered uniform over the entire area of the panel 2
`by adjusting the light scattering processing part 12 or the
`pattern of the re?ector sheet 13, as in Embodiment 2.
`The liquid crystal display device according to Embodi
`ment 2 or 3 employs the aforementioned structure and hence
`offers the following effects.
`(1) It is possible to remove the inner light guiding part 40 or
`4d without removing the ?ame 1b by merely removing the
`holding members 14a and 14b mounted on the frame 1b.
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`10
`
`20
`
`30
`
`6
`(2) Since the outer light guiding part 4a serves as a sup
`porting member, the light guiding board is supported with a
`higher strength.
`(3) The provision of the vacancy in the inner light guiding
`part 40 or 4d enables the device to be made light in weight.
`(4) Since the major part of the light incident on the inner
`light guiding part 4c or 4d is directed downward to the light
`scattering processing part 12 and to the pattern of the
`re?ector sheet 13, the light can be utilized with a higher
`e?iciency.
`Embodiment 4
`FIGS. 7(a) and 7(b) are sectional views showing the
`structure of one embodiment of a liquid crystal display
`device according to the third aspect of the present invention.
`Since the basic structure is similar to Embodiment l,
`descriptions of common parts are omitted
`As in Embodiment 1, the liquid crystal display device
`according to Embodiment 4 includes a light guiding board 4
`between lamps 5a and 5b held by means of holding members
`14a and 14b mounted on the frame 1b, as shown in FIGS.
`7(b), 3, and 4.
`Since the device according to Embodiment 4 is less rigid
`than the devices according to Embodiments 1 to 3, a
`reinforcing ?ame 22 is included. FIG. 8(a) is a view of the
`device as viewed from below, and FIG. 8(b) is a sectional
`view taken along line 8b-8b of FIG. 8(a).As shown in FIG.
`8(b), the reinforcing ?ame 22, which may be a metal or an
`acrylic resin, bridges across the lamp holders 10a and 10b.
`Numeral 25 denotes a guide along which the light guiding
`board 4 is ?tted into the device.
`The light guiding board 4 is attached to the frame ?om
`below and then held by means of the holding members 14a
`and 14b (not shown in FIG. 8) mounted on the frame 1 as
`in Embodiment 1.
`The liquid crystal display device according to Embodi
`ment 4 operates as follows. Of the light rays incident on the
`light guiding board 4 ?om the lamps 5a and 5b, those
`re?ected upward by the light scattering processing part ‘12
`and re?ector sheet 13 on the lower side of the light guiding
`board 4 are rendered uniform and directed toward the liquid
`crystal display panel by the diffusing plate 27.
`The liquid crystal display device according to Embodi
`ment 4 exhibits the following effects.
`(1) The opening under the light guiding board 4 allows the
`light guiding board 4 to be readily removed without detach
`ing the ?ame 1b by merely removing the holding members
`14a and 14b.
`(2) Since the light guiding board 4 is not divided, light losses
`that would occur at the connecting portion of a divided light
`guiding board never occur so light is utilized with a higher
`e?iciency.
`(3) Since the light guiding board 4 is not divided, attachment
`and removal of the light guiding board 4 and diffusing plate
`27 is achieved easily when the liquid crystal display device
`is applied to an OHP system.
`Embodiment 5
`FIGS. 9(a) and 9(b) are sectional views showing the
`structure 10 of one embodiment of a liquid crystal display
`device according to the fourth aspect of the present inven
`tion. In the device shown, holding members 16a and 16b are
`disposed on opposite lower ends of the liquid crystal display
`panel 2, and ?xed to the panel 2 and circuit boards 3a and
`3b by means of screws or an adhesive. Each of the holding
`members 16a and 16b is screwed at its lateral side and
`bottom to a lower portion of the ?ame 1b and at its top and
`lateral side to an upper portion of the frame 1a.
`A light guiding board 4e containing lamps 5 is ?tted
`between the holding member 16a and 16b and supported on
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`its lower side by holding members 14a and 14b mounted on
`lower portions of the frame 1b as in Embodiment l.
`The liquid crystal display device according to Embodi
`ment 5 operates as follows. Light rays emitted from the
`lamps 5 embedded within the light guiding board 4e are
`added together at the surface of the light guiding board 4e,
`while unevenness in light intensity is evened by the light
`scattering processing part 12 and the pattern of the re?ector
`sheet 13 on the lower side of the light guiding board 4e. The
`light rays are then rendered uniform and applied to the liquid
`crystal panel 2 by means of the di?using plate 27.
`The lamps are embedded within the light guiding board 4e
`so that the lamps are securely held and easily handled since
`the liquid crystal display panel 2 is evenly illuminated by the
`thin light guiding board 4e, thereby contributing to the
`construction of a thin liquid crystal display device. To
`enhance the above elfects, there might be formed a light and
`shade pattern in which a carbon-powder pattern is developed
`in the light guiding board
`The liquid crystal display device according to Embodi
`ment 5 employs the aforementioned structure and exhibits
`the following effects.
`(1) The light guiding board 4e can readily be removed
`without detaching the frame 112 by merely removing the
`holding members 14a and 14b mounted on lower portions of
`the frame 1b.
`(2) Of light rays emitted from the lamps embedded within
`the light guiding board 4e, those running directly upward
`and those re?ected by the light scattering processing part 12
`and the pattern of the re?ector sheet 13 on the lower side of
`the light guiding board 40 are added together, thereby
`etfectively utilizing omnidirectional light rays. This arrange
`ment realizes a lighting unit section A having lower power
`consumption.
`(3) The lighting unit section can be entirely removed from
`the liquid crystal'displ'a'y panel, thus assuring a liquid crystal
`display device with a smaller weight and higher manipula
`bility.
`As has been described, the liquid crystal display device
`according to the ?rst aspect of the present invention has a
`structure wherein the inner light guiding part 4b is ?tted into
`the outer light guiding part 4a and held by the holding
`members 14a and 14b from below. Such a structure allows
`the inner light guiding part 4b to be readily removed without
`detaching the frame 1b by merely removing the holding
`members 14a and 14b.
`Further, the outer light guiding part 4a serves also as a
`supporting member for the lamp holders on opposite sides.
`Therefore, deformation of the device is less likely. In
`addition, the device has a simpli?ed structure, allows the
`inner light guiding part 4b and dilfusing plate 27 to be
`removed simultaneously, and offers higher manipulability.
`In the liquid crystal display device according to the
`second aspect of the present invention the inner light guiding
`part 40 or 4d is held in the same manner as in the device
`according to the ?rst aspect. Hence, it is possible to readily
`remove the inner light guiding part 40 or 4d without detach
`ing the frame 1b by merely removing the holding members
`14a and 14b.
`Further, the inner light guiding part 40 or 4d has a beveled
`shape from the opposite ends toward the center to de?ne the
`vacancy 28 so that the device is lighter.
`With the liquid crystal display device according to the
`third aspect of the present invention, it is possible to readily
`remove the light guiding board 4 without detaching the
`frame 1b by merely removing the holding members 14a and
`14b mounted on the frame 1b outside the lateral sides,
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`adjoining the lamps, of the light guiding board 4. Further, the
`device has a simpli?ed structure and has a higher manipu
`lability.
`The liquid crystal display device according to the fourth
`aspect of the present invention has a structure wherein the
`light guiding board 4e containing the lamps is held by the
`holding members 14a and 14b. Such a structure allows the
`light guiding board 4e to be readily removed without detach
`ing the frame 1b by merely removing the holding members
`14a and 14b mounted on the frame 1b.
`Further, since the light source 5 is embedded within the
`light guiding board 4e, light is utilized ef?ciently with
`reduced power consumption. In addition, the device ?om
`which the light guiding board is removed is light weight and
`simple, thus offering good manipulability.
`While only certain presently preferred embodiments have
`been described in detail. as will be apparent to those familiar
`with the art, changes and modi?cations can be made without
`departing from the spirit and scope of the invention as
`de?ned by the following claims.
`What is claimed is:
`1. A liquid crystal display device comprising:
`a liquid crystal display panel;
`lamps;
`lamp holders holding respective lamps;
`a light guiding board positioned between the lamps; and
`a frame supporting the lamp holders, wherein the light
`guiding board comprises an outer light guiding part
`?xed to the lamp holders, and an inner light guiding
`part removably ?tting into and securable within the
`outer light guiding part with a holding member remov
`ably mounted to the frame.
`2. The liquid crystal display device according to claim 1
`comprising:
`a dilfusing plate disposed on a ?rst side of the inner light
`guiding part for diffusing light passing through the
`inner light guiding part;
`a light scattering part disposed on a second side of the
`inner light guiding part for directing light from the
`lamps toward the liquid crystal display panel; and
`a re?ector sheet disposed on the second side of the inner
`light guiding part for re?ecting light from the lamps
`toward the liquid crystal display panel in a pattern.
`3. The liquid crystal display device according to claim 1
`wherein the holding member comprises a leaf spring.
`4. The liquid crystal display device according to claim 1
`wherein the holding member comprises a plate spring.
`5. A liquid crystal display device comprising:
`a liquid crystal display panel;
`lamps;
`lamp holders holding respective lamps;
`a light guiding board positioned between the lamps; and
`a frame supporting the lamps and the lamp holders,
`wherein the light guiding board comprises an outer
`light guiding part ?xed to the lamp holders, and an
`inner light guiding part removably ?tted into and
`securable within the outer light guiding part with a
`holding member removably mounted to the frame, the
`light guiding board having ?rst and second surfaces and
`?rst and second edges, the ?rst surface being convex or
`concave.
`6. The liquid crystal display device according to claim 5
`wherein the ?rst surface is convex.
`7. The liquid crystal display device according to claim 5
`wherein the ?rst surface is concave.
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`8. The liquid crystal display device according to claim 5
`comprising:
`a diffusing plate disposed on a ?rst side of the inner light
`guiding part for di?using light passing through the
`inner light guiding part;
`a light scattering part disposed on a second side of the
`inner light guiding part for directing light from the
`lamps toward the liquid crystal display panel; and
`a re?ector sheet disposed on the second side of the inner
`light guiding part f