WO2000060280A1 - Illuminateur et affichage a cristaux liquides comprenant cet illuminateur - Google Patents
Illuminateur et affichage a cristaux liquides comprenant cet illuminateur Download PDFInfo
- Publication number
- WO2000060280A1 WO2000060280A1 PCT/JP2000/001570 JP0001570W WO0060280A1 WO 2000060280 A1 WO2000060280 A1 WO 2000060280A1 JP 0001570 W JP0001570 W JP 0001570W WO 0060280 A1 WO0060280 A1 WO 0060280A1
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- WIPO (PCT)
- Prior art keywords
- light guide
- light
- groove
- depth
- light source
- Prior art date
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0038—Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0058—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
- G02B6/0061—Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0045—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide
- G02B6/0046—Tapered light guide, e.g. wedge-shaped light guide
Definitions
- Lighting device and liquid crystal display device using the lighting device are Lighting device and liquid crystal display device using the lighting device
- the present invention relates to an illuminating device used as a backlight of a liquid crystal display device and a liquid crystal display device using the illuminating device.
- the present invention relates to a device and a liquid crystal display device using the same. Background art
- liquid crystal display devices have been frequently used for displaying images on personal computers, word processors, video cameras, and the like.
- FIG. 15 shows a conventional liquid crystal display device.
- 51 is a light guide
- 52 is a plurality of dot patterns printed on the back surface of the light guide with white ink, a light diffusion surface having a plurality of convex portions
- 53 is an example.
- 54 is a light reflector that reflects the light emitted from the cold cathode fluorescent tube
- 55 is a light reflection sheet
- 56 is a light diffuser that is placed close to the upper surface of the light guide 51.
- Reference numeral 57 denotes a prism sheet further disposed on the upper surface
- reference numeral 7 denotes a liquid crystal display element disposed on the upper surface of the prism sheet 57.
- the light source 53 when the light source 53 is turned on, the direct light of the light source 53 and the light reflected by the light reflector 54 are incident on the light guide 51, and the incident light is transmitted to the light guide 51. Propagating inside and diffusing light at the light diffusing surface 52 Then, the light is radiated to the outside of the light guide 51, and the light emitted from the lower surface of the light guide 51 is reflected by the light reflection sheet 55, and is again emitted from the light guide 51. Light enters the light guide 51 and is emitted from the upper surface of the light guide 51.
- the light emitted from the upper surface of the light guide 51 is diffused by the light diffusing plate 56, so that the light diffusing surface of the light guide 51, for example, a dot turn can be invisible.
- the light diffused by the light diffusion plate 56 is regulated in the front direction by the prism sheet 57 and irradiates the liquid crystal display element 7 with light from the back. At this time, if the liquid crystal display element 7 is driven by a drive circuit (not shown), an image can be visually recognized on the display screen.
- the conventional liquid crystal display has some problems.
- the light diffusing surface 52 on the back of the light guide 51, the light reflection sheet 55, and the upper surface of the light guide 51 Light efficiency is reduced due to light absorption by the light diffusion plate 56 and the prism sheet 57 arranged.
- a light reflecting sheet 55 on the back of the light guide 51 a light diffusing plate 56, a prism sheet 57 on the top of the light guide 51, and various sheets for using a large number of sheets.
- liquid crystal display devices with a wide viewing angle of 140 degrees and 160 degrees have been put to practical use, but that is not enough.
- the present invention has been made to solve such a problem, and provides a lighting device and a liquid crystal display which overcome the problem of the viewing angle by increasing the efficiency of use of light, thereby eliminating the need for mounting a prism chip.
- the purpose is to provide equipment. Disclosure of the invention
- a lighting device has a lower surface inclined with respect to a horizontal upper surface of a light guide for guiding light emitted from a light source, and one of the light guides having a larger thickness is provided.
- a light source is arranged on the side surface, and a light reflection sheet is arranged on the lower surface side of the light guide.
- a plurality of groove groups are provided on the inclined lower surface of the light guide, and these individual groove groups and adjacent groove groups are connected by a flat surface.
- the plurality of groove groups are formed on the lower surface such that the depth of each groove of the groove group gradually increases as the distance from one side surface of the light guide increases, and light diffusion is performed on the upper surface side of the light guide.
- a plate is arranged.
- Another illuminating device of the present invention has a shape in which two light guides used in the illuminating device of the first invention are used and the thin side surfaces of the light guide are stuck together at the center.
- Light guides are used, light sources are arranged on both sides with a large thickness, light reflection sheets are arranged along the lower surface of the light guide, and a light diffusing plate is provided on the upper surface of the light guide.
- a plurality of grooves are provided on the lower surface of the light guide, and the depth of the grooves is gradually increased from both sides of the light guide toward the center.
- Still another illumination device includes a light guide having an upper surface and a lower surface parallel to each other, a light source disposed on one side surface of the light guide, and a light guide disposed on a lower surface side of the light guide.
- a light reflecting sheet and a light diffusing plate provided on an upper surface of the light guide; a plurality of groove groups parallel to the one side surface provided on a lower surface of the light guide; The depth of each groove of the group of grooves gradually increases as the distance from the one side surface increases.
- the present invention provides a liquid crystal display device in which a liquid crystal display element is arranged above a light diffusion plate of the above-mentioned lighting device.
- FIG. 1 is a cross-sectional view of a main part of a liquid crystal display device using the lighting device according to the first embodiment of the present invention.
- FIG. 2 is a schematic plan view of the light guide shown in FIG. Fig. 3 is a cross-sectional view taken along line B-B in Fig. 2
- Fig. 4 is a partially enlarged view of Fig. 3
- Fig. 5 is viewed from the lower surface of the light guide shown in Fig. 1.
- FIG. 6 is a partially enlarged view of a groove group provided on the lower surface of the light guide in the embodiment of FIG. 1
- FIG. 7 is a view of the light guide in the embodiment 1 shown in FIG. FIG.
- FIG. 8 is a diagram showing the relationship between the thickness, the depth of the groove group of the groove on the lower surface of the light guide, and the width of the groove group.
- FIG. 9 is a vertical luminance distribution diagram of a display screen of the liquid crystal display device according to the first embodiment of the present invention and a conventional liquid crystal display device using a light guide based on the configuration relationship diagram of FIG. Figure 7
- FIG. 4 is a diagram illustrating a luminance distribution in a horizontal direction of a display screen of the device.
- FIG. 10 is another embodiment showing the relationship between the thickness of the light guide, the depth of the groove of the groove group on the lower surface of the light guide, and the width of the groove group in the first embodiment.
- FIG. 3 is a diagram showing a configuration relationship of a light guide.
- FIG. 11 is a cross-sectional view of a main part of a liquid crystal display device using the lighting device according to the second embodiment of the present invention.
- FIG. 12 is a cross-sectional view of a main part of a liquid crystal display device using the lighting device according to the third embodiment of the present invention.
- FIG. 13 is a sectional view of the light guide in the embodiment shown in FIG. It is the elements on larger scale of the groove
- FIG. 14 is a partially enlarged view of a groove formed on a lower surface of a light guide in a lighting device according to Embodiment 4 of the present invention.
- FIG. 15 is a sectional view of the configuration of a conventional liquid crystal display device. BEST MODE FOR CARRYING OUT THE INVENTION
- FIG. 1 is a cross-sectional view of a main part of a liquid crystal display device using the lighting device according to the first embodiment of the present invention.
- reference numeral 1 denotes a light guide and acrylic resin.
- the light guide 1 is made of a synthetic material of a transparent resin such as polycarbonate, and the upper surface 8 of the light guide 1 has a shape of a wedge in which the lower surface 9 is almost horizontal and the lower surface 9 is inclined.
- Reference numeral 2 denotes a plurality of groove groups provided on the lower surface 9 of the light guide 1, and each groove group has at least two grooves.
- Reference numeral 3 denotes a light source arranged close to one side surface 10 of the light guide 1 where the thickness of the light guide 1 is large.
- Reference numeral 4 denotes a light reflector, which surrounds the light source 3. The light from the light source 3 is reflected in the direction of one side 10 of the light guide 1.
- a resin sheet is made of a material having a high light reflectance such as silver or aluminum.
- the light reflector 4 is formed by depositing a thin film, or a thin aluminum metal plate.
- Numeral 5 denotes a light reflection sheet, which is arranged so as to cover the lower surface 9 of the light guide 1 and the other side surface (the end of the light guide 1 farthest from the light source 3).
- Reference numeral 6 denotes a light diffusing plate disposed close to the upper surface 8 of the light guide 1, which is formed by dispersing a material having a different refractive index inside a transparent resin sheet or forming irregularities on the surface of the transparent sheet. Things are used.
- FIG. 2 is a schematic plan view of the light guide 1 as viewed from above.
- a plurality of grooves 11 are formed on the upper surface of the light guide 1 in a direction perpendicular to the longitudinal direction of the light source 3, that is, in a direction perpendicular to one side surface 10 of the light guide 1.
- the light guide 1 has a region indicated by a broken line instead of a reference numeral, and that the groove 11 is also formed in this broken line region.
- FIG. 3 in which the plan view in FIG. 2 is cut along the line B--B and FIG. 4 which is a partially enlarged view thereof, for example, the plurality of grooves are continuously formed in the same shape. It has been done.
- the pitch between the peaks of the grooves shown in FIG. 4 or between the valleys of the grooves is about 50 m, and the depth of the grooves is about 20 ⁇ m.
- the light guide 1 constituting the lighting device of the present invention has grooves formed not only on the lower surface 9 but also on the upper surface 8 thereof. This is for condensing the emitted light from the liquid crystal display element 7.
- the formation of a groove in the upper surface 8 of the light guide 1 is not always an essential requirement.
- the liquid crystal display device of the present invention includes a liquid crystal display element 7 above the light diffusion plate 6.
- a liquid crystal display element 7 above the light diffusion plate 6.
- two transparent glass substrates are superposed at intervals so that the display electrode of the transparent conductive film and the surface on which the alignment film and the like are laminated face each other, and both substrates are sealed with a sealing material.
- the liquid crystal is sealed inside the sealing material by pasting together, and a polarizing plate is provided outside both substrates.
- FIG. 5 is a schematic plan view seen from the lower surface 9 side of the light guide 1 in FIG. 1, and the light source 3 is disposed close to and along one side surface 10 of the light guide 1. .
- the groove group 2 is formed substantially parallel to one side surface 10 of the light guide 1.
- the direction of the groove formed on the lower surface 9 is arranged almost in parallel with the one side surface 10 because the reason is to increase the light reflection efficiency, and it is not necessary to arrange the groove in parallel. If they are orthogonal, the reflection efficiency of light in the groove will decrease.
- the depth of the groove is smaller than the depth of the groove of the groove group 2 and the depth of the groove is smaller.
- a substantially uniform groove may be formed.
- FIG. 6 is a partially enlarged sectional view of a plurality of groove groups indicated by the partial frame A in FIG. 1.
- the grooves 12 and 13 of the groove group 2-1 have the same depth h1.
- the grooves 14 and 15 of the groove groups 2 and 2 are formed in the same shape at substantially the same depth h2, and the adjacent groove groups 2 and 1 and the groove groups 2 and 2 are formed in the same shape.
- Grooves 1 2, 1 3 and 14, 15 in groove group 2 — 1, 2 — 2 have similar shapes, and these shapes are V-shaped, similar to the shape of a chevron or saw blade Formed in the groove.
- the angle of inclination of the V-shaped groove is about 55 degrees, and the angle of inclination formed by the flat surface 16 and some lines constituting the groove 14 is set to about 130 degrees.
- the depth h2 of the groove is larger than h1, and the depth of the groove group is from one side 10 to the other side of the light guide 1 in which the light source 3 is arranged. It is formed so that it gradually increases as it goes away.
- the light emitted from the light source 3 is reflected light reflected by the light reflector 4 and direct light.
- the light is incident on the light guide 1 through the side surface 10.
- the light incident on the light guide 1 propagates inside the light guide 1 while being totally reflected by the upper surface 8 and the lower surface 9 of the light guide 1, but the groove on the lower surface 9 of the light guide 1
- Light incident on the slopes of the grooves 12, 13 and 14, 15 of groups 2-1 and 2-2 is reflected on the slopes, returned to the light guide 1 again, or passed through the slopes. Is reflected by the light reflection sheet 5 and re-enters the light guide.
- Most of the light whose incident angle on the upper surface 8 is smaller than the total reflection angle passes through the upper surface 8, and is emitted from the light guide 1.
- the light incident on the light guide 1 propagates inside the light guide 1, and is reflected by the plurality of groove groups 2, passes through the light, and reflects the light reflected by the light reflection sheet 5. Passing through the upper surface 8 of the light guide 1 by re-entering the light guide 1 As a result, the light is emitted outside the light guide 1.
- the depth of each groove of the groove group 2 on the lower surface 9 of the light guide 1 is increased as the distance from one side face 10 of the light guide 1 where the light source 3 is arranged increases. This is because the amount of light in the light guide 1 increases as the distance from the light source 3 increases and decreases as the distance from the light source 3 increases, so that the variation in brightness on the upper surface 8 of the light guide 1 is reduced.
- the light emitted to the upper surface 8 of the light guide 1 of the lighting device has its light-collecting efficiency increased by the grooves 11 on the upper surface 8, and the light is diffused by the light diffusion plate 6, and the liquid crystal display is formed. Element 7 is illuminated from the back. At this time, if the liquid crystal display element 7 is driven by a driving device (not shown), an image can be viewed on the display screen in front of the liquid crystal display element 7.
- the symbol S shown on the horizontal axis indicates the position of one side surface 10 of the light guide 1 where the light source 3 is arranged in proximity
- E indicates the terminal position which is the position of the other side surface of the light guide 1.
- the vertical axis represents the thickness t of the light guide 1, the pitch p of the groove group 2, and the depth h of the groove group 2, respectively.
- the pitch p of the groove group can be described by the groove group 2-2 shown in FIG. 6, and the width a of the flat surface 16 and the individual grooves 14 and 15 of the groove group 2-2
- the light guide 1 gradually decreases its thickness t from the position S on one side surface 10 where the light source 3 is arranged to the position E on the other side surface, Conversely, although the depth h of each groove in the groove group is gradually increased, the pitch p of the groove group is constant regardless of the position of the length of the light guide 1.
- the specific thickness t of the light guide 1 is one side surface of the light guide 1, that is, the thickness on the side where the light source 3 is disposed is 2.5 mm, and the other side farthest from the light source 3. It is set to 0.5 mm on the side.
- the depth h of the groove of the groove groups 2-1 and 2-2 is in the range of 5 to 2 Oim in the entire light guide 1.
- the pitch p is fixed at approximately 110 m regardless of the position of the light guide 1.
- the width of the flat surface a is in the range of 50 to 100 m in the entire light guide 1, the width b of the groove is 10 m to 50 m, and the connection part c is about 5 ⁇ m It is.
- the present invention is characterized in that the ratio of the flat surface a occupying the pitch p is selected to be large.
- the following is a more detailed explanation of these relationships.
- h 6.3 m
- a 91
- b 1
- l ⁇ m
- c 4.9 m
- p 110 / im. Therefore, the ratio aZp of the flat surface a to the pitch p exceeds 80%.
- the ratio bZp occupied by the groove width b is about 13%, as easily obtained from the above values.
- the ratio b Z p occupied by the groove width b is about 40%, which is smaller than the ratio occupied by the flat surface.
- the feature of the present invention is that grooves 2, 2-1, and 2-2 are formed on the lower surface 9 of the light guide 1, and these grooves are used to guide the light.
- the ratio in the light body 1 is smaller than the ratio in the flat surface 16.
- the vertical and horizontal dimensions of the planar shape of the light guide 1 of Embodiment 1 of the present invention shown in FIGS. 1 to 7 are rectangular shapes of about 40 m and 30 mm, respectively. That is, looking straight at FIG. 2, the length of the light guide 1 in the vertical direction is about 40 mm, and the length in the horizontal direction is about 30 mm. As described above, the thickness of one side face 10 is about 2.5 mm, and the thickness of the other side face farthest from the one side face 10 is about 0.5 mm.
- the diameter of the light source 3 composed of a straight-tube cold-cathode fluorescent tube is about 1.8 mm, which is smaller than the thickness of the side surface 10.
- FIG. 7 shows the relationship between the length, the thickness, the depth of each of the plurality of grooves of the groove group on the lower surface, and the pitch of the groove groups in the light guide 1 in the lighting device of the present invention having the above configuration.
- a liquid crystal display device having a groove as shown in FIG. 4 formed on the upper surface 8 of the light guide 1 was produced.
- the liquid crystal display device shown in FIG. 15 was manufactured with the same outer dimensions, light source dimensions and brightness as in the case of the light guide 1 of the present invention. I tried.
- Figures 8 and 9 show the results of these comparisons. 9 shows the measurement results of the luminance distribution in the vertical direction and the horizontal direction of the child 7.
- FIG. 8 shows a vertical luminance distribution of the liquid crystal display element 7, that is, a measurement point on the screen when the display screen is rotated in the front-to-back direction while facing the display screen of the liquid crystal display device. Shows the luminance at.
- FIG. 9 shows the luminance distribution in the horizontal direction, and shows the luminance distribution at the measurement points on the screen when the display screen facing the viewer is rotated left and right.
- the solid line indicated by reference symbol Q indicates the luminance distribution of the liquid crystal display device of the present invention
- the broken line indicated by reference symbol R indicates the luminance distribution of the conventional device.
- the “brightness ratio” displayed on the vertical axis in FIGS. 8 and 9 is based on the brightness (absolute value 1.0) when the radiation angle for rotating the display screen back and forth and right and left is 0 degrees.
- the relative luminance ratio is shown by comparing the brightness at each rotation angle when the display screen is rotated back and forth and left and right with the reference value.
- the “radiation angle” displayed on the horizontal axis in FIGS. 8 and 9 represents the angle itself when the display screen is rotated back and forth and right and left.
- the conventional device shows that the horizontal and horizontal radiation angles decrease significantly from around 20 degrees in the horizontal direction. It can be seen that the luminance is much lower than in the vicinity and the luminance distribution itself fluctuates greatly. This means that image recognition deteriorates at about 20 degrees left and right in the horizontal direction and about 30 degrees back and forth in the vertical direction.
- the flat surface 16 is formed between the groove group and the adjacent groove group, but the flat surface 16 is formed at the pitch p.
- FIG. 10 shows another embodiment of the light guide 1, and at a position S on one side face 10 on which the light source 3 is arranged, the depth of the groove of the groove group 2 in the vicinity thereof is shown. Is relatively small and uniform, and the pitch P of the groove group is gradually reduced from the position S of the side surface 10 toward the end M of the adjacent portion, and the end M of the side position adjacent portion M Thus, at the other side position E, the depth h of the groove group was gradually increased, and the width p of the groove group was almost constant without any difference between the grooves.
- the light guide 1 shown in FIG. 10 is larger than that described with reference to FIGS. 2, 5, and 7, and its vertical and horizontal dimensions are 60 mm, respectively. It was about 50 mm.
- the size shown in FIG. 7 was obtained.
- the decrease in brightness at a very small but large emission angle in the vertical and horizontal directions of the liquid crystal display element 7 was improved. This was confirmed.
- the depth of the groove from the position S of one side surface 10 to the end of the adjacent portion is formed smaller than that of the other grooves, but the depth is also larger in these regions.
- the pitch p of the groove group is gradually reduced.
- the incident light from the light source 3 is not reflected much in the vicinity of the light source 3 and is directed toward the other side E, which is the farthest from one side of the light guide 1. This is because the incidence was promoted.
- the thickness t of the light guide 1, the depth h of the grooves of the groove group, and the size of the pitch p shown in FIG. 10 are the same at the position of the one side surface 10 (S).
- the breakdown of the pitch p is as follows: the size of the flat surface (a) is 280 m, the width (b) of the groove group is 10 m, and the connection part (c) is 6 m.
- the pitch p is shown in FIG. 10 from the position of one side surface (S) to the vicinity (M) thereof. In this way, it is gradually reduced.
- the depth h of the groove from the proximity (M) to the other side (E) is gradually increased from 7.8 to 19.8 / xm. Chi is fixed at 132 m regardless of the position of the light guide 1.
- the pitch The ratio of the flat surface a of the groove occupying the lower surface 9 of the light guide 1 is set to be larger than the ratio occupied by the grooves of the groove group 2.
- the performance of the illuminating device is improved by increasing the ratio of the flat surface to the ratio of the unevenness of the groove formed in the light guide 1. It is.
- FIG. 11 is a cross-sectional view of a main part of a liquid crystal display device using an illumination device according to a second embodiment of the present invention.
- the two light guides according to the first embodiment have the other thin side surface. We made a light guide with a shape that was glued together at the center.
- reference numeral 19 denotes a light guide having a lower surface with respect to a horizontal upper surface
- reference numeral 20 denotes a plurality of groove groups formed on the lower surface of the light guide 19.
- the right and left portions of the central portion 26 were formed symmetrically, and the groove groups 20 were formed in the same manner as in the first embodiment.
- Numerals 21 and 22 denote light sources composed of elongated straight tube-shaped cold cathode or hot cathode fluorescent tubes which are arranged close to each other along both side surfaces of the light guide 19.
- the light source 21 is disposed on the first side of the light guide 19, and the light source 22 is disposed on the second side of the light guide 19.
- the groove group 20 is not formed immediately from the first side surface and the second side surface, but as far as the vicinity of the first and second side surfaces as described in the first embodiment. Another groove is formed between them, and a groove group whose depth gradually increases from the adjacent portion toward the other side surface is formed.
- reference numerals 23 and 24 denote the same light reflectors as in the first embodiment
- reference numeral 25 denotes a light reflection sheet arranged along the lower surface of the light guide 19, which is the same as the first embodiment.
- Materials such as acryl resin and polycarbonate were used.
- the upper surface 27 of the light guide 19 has the same groove as that of the first embodiment, that is, the same shape in the direction orthogonal to the light sources 21 and 22 in order to increase the light collection efficiency. Grooves may be applied continuously.
- This embodiment is suitable for a light guide 19 having a larger area from which light is radiated from the upper surface 27, and light sources 21 and 22 are arranged close to both side surfaces of the light guide 19.
- a light guide 19 having a large light emission area can achieve high luminance and high light efficiency, and the horizontal and vertical luminance distributions of a liquid crystal display element (not shown) are the same as in the first embodiment. Can be very good.
- FIG. 12 is a cross-sectional view of a main part of a liquid crystal display device according to a third embodiment of the present invention, in which 28 is a light guide whose upper surface and lower surface are parallel, and 29 and 30 are as described above. The same light source and light reflector are shown, respectively, and 31 is a light reflection sheet.
- the groove 32 on the lower surface of the light guide 28 has a shape shown in FIG. 13 in which the partial frame F in FIG. 12 is enlarged.
- Grooves 3 2-1 of grooves 3 3, 3 4 have the same shape, grooves 3 2-2 of grooves 3 5, 3 6 have the same shape, and grooves 3 2-3 of grooves Three
- the grooves 7 and 38 have the same shape, and the grooves of the groove groups 32-1, 3212 and 32-3 have similar shapes.
- the groove depths h 3, h 4, and h 5 of these groove groups are smaller and closer to one side of the light guide 28 where the light source 29 is located, and are farther away from this side. As the depth increases, the depth of the groove increases. That is, groove group 3 2 — groove depth h 3, groove group 3
- the depth h 4 of the groove 2 ⁇ 2 and the depth h 5 of the groove of the groove group 3 2 ⁇ 3 are selected so that h 3 ⁇ h 4 ⁇ 5.
- the light guide 28 has a rectangular parallelepiped shape, and the brightness distribution is slightly different from that of the wedge shape shown in the first embodiment.
- the connection flat surface 3 9 has a width a 1 and a groove 3 5,
- a groove may be formed on the upper surface 8 of the light guide 28 as well. As a result, the light collection efficiency of the light guide 28 is further improved.
- FIG. 14 is a fourth embodiment of a lighting device according to the present invention, and is a partially enlarged cross-sectional view of a light guide used in the lighting device. It differs from the first to third embodiments in that the groove group formed on the lower surface 9 of the wedge-shaped light guide 1 in the first embodiment is formed by a single groove.
- the grooves 41, 42 and 43 are formed in a similar shape, and the depths h6, h7 and h8 of the individual grooves are determined on one side of the light guide 1 where the light source is arranged (not shown). ) Gradually increases as the distance increases.
- the widths a 3, a 4 and a 5 of the flat surfaces 44, 45 and 46 connecting the grooves 41, 42 and 43 and the widths b 3 and b of the respective grooves By adjusting the pitches p 3, p 4 and p 5 of each of 4 and b 5 individually, and the groove depths h 6, h 7 and h 8 as appropriate, an optimum luminance distribution can be obtained. I'll do it.
- 47, 48 and 49 are connecting portions for connecting the grooves 41, 42 and 43 to the flat surfaces 45.46 and 50, and the gradient of the connecting portion toward the flat surface is shown. If it is as steep as possible, it can be considered as a part of the grooves 41, 42 and 43.
- the connection portions 47 to 49 are not essential components in the present invention.
- a single groove is formed in the wedge-shaped light guide 1 of the first embodiment, but it may be formed in the rectangular parallelepiped light guide 28 of the embodiment of FIG. Needless to say, as described above, the optimum luminance distribution may be set by adjusting the depth of the groove, the width of the groove, and the like.
- a groove may be formed on the upper surface 8 of the light guide 1.
- the liquid crystal display element to be used is not specified, but it is preferable to use a device having a viewing angle as wide as possible, for example, 140 degrees or 160 degrees. It goes without saying that the horizontal and vertical luminance distributions are even better. Nor.
- the number of grooves in the groove group on the lower surface of the light guide is shown as two. However, three or four grooves are used, and the number of the target object or the liquid crystal display screen is increased. Depending on the size and the like, the brightness distribution may be adjusted appropriately while observing the state.
- the surface facing the light source of the plurality of grooves and the plurality of single grooves in the plurality of groove groups on the lower surface of the light guide needs to be inclined. The gradient may be adjusted while observing the state of the luminance distribution.
- a groove having substantially the same depth is formed from one side to the side adjacent to the side, and the other side from the side adjacent to the side.
- a plurality of groove portions whose depth gradually increases toward the portion may be formed.
- the shape and width of the grooves may be adjusted while confirming the luminance distribution.
- the light source used may be either a cold cathode type or a hot cathode type fluorescent tube, but the cold cathode type is more compact than the hot cathode type due to the electrode configuration.
- a cold-cathode fluorescent tube is preferred because it can be used. You can also use LED.
- the lighting device has the lower surface inclined with respect to the horizontal upper surface of the light guide that guides light emitted from the light source, and the one side surface where the thickness of the light guide is large.
- the light source is placed on the side and the light A shooting sheet is arranged.
- a plurality of groove groups are provided on the lower surface of the light guide, and each of the groove groups and the adjacent groove group are connected by a flat surface. The plurality of groove groups are formed so that the depth of each groove of the groove group increases as the distance from one side surface of the light guide increases.
- the efficiency of light reflection within the light guide and the effect of emitting light from the light guide are improved, so that the prism sheet disposed on the upper surface side of the light guide can be mounted. Can be eliminated.
- the lighting device of the present invention employs a light guide in which the thickness of the central portion of the light guide is thinner than both side surfaces thereof, and the light sources are arranged on both side surfaces having a large thickness to face each other.
- a light reflection sheet is arranged along the lower surface of the light guide, and a light diffusion sheet is arranged on the upper surface of the light guide.
- the illumination device of the present invention further provides a light guide with high light efficiency, and thus eliminates the need for a prism sheet disposed on the upper surface of the light guide, which has been an essential component in the past. It can be In addition, since a prism sheet is not required, alignment with other light diffusing plates or light reflection sheets becomes relatively easy, and there is little danger of foreign substances being mixed between the sheets. It is possible to provide a lighting device in which deterioration is improved and which is advantageous in terms of cost.
- the lighting device of the present invention includes a light guide having an upper surface and a lower surface parallel to each other, a light source disposed on one side surface of the light guide, and a light reflecting sheet disposed on a lower surface side of the light guide. And a light diffusing plate provided on the upper surface of the light guide, wherein a plurality of groove groups are provided on the lower surface of the light guide, and the depth of the plurality of groove groups is the one As the distance from the side increases, it grows larger. Further, in the lighting device of the present invention, a groove having substantially the same depth is formed substantially parallel to the one side surface from one side surface of the lower surface of the light guide to a portion close to the side surface. As a result, the light reflection efficiency is further increased, and light can be used effectively.
- the lighting device of the present invention further provides a light guide with high light efficiency, so that the prism sheet, which is required on the conventional device, is disposed on the upper surface of the light guide. Can be unnecessary.
- a prism sheet is not required, alignment with other light diffusion plates or light reflection sheets becomes relatively easy, and there is little danger of foreign matter entering between sheets, and quality is reduced. It is possible to provide a lighting device in which deterioration is improved and which is advantageous in terms of cost.
- the luminance distribution in the horizontal and vertical directions of the liquid crystal display element can be improved as compared with the conventional device.
- the lighting device and the liquid crystal display device of the present invention are characterized in that firstly, the shape of the light guide is characterized, and secondly, the lower surface of the light guide.
- a groove is formed on the side that reflects light, but the depth of the groove is gradually increased in the light traveling direction.
- Third, a groove is also formed on the upper surface of the light guide. Since the light reflection efficiency can be increased by these combinations, it is possible to eliminate the need for a prism sheet, which has been an essential component in the past. It was done.
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/936,914 US6629764B1 (en) | 1999-03-30 | 2000-03-15 | Illuminator and LCD device comprising the illuminator |
EP00909645A EP1174659A4 (en) | 1999-03-30 | 2000-03-15 | LIGHTING AND LIGHTING CRYSTAL DISPLAY CONTAINING LIGHTING |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11088757A JP2000285719A (ja) | 1999-03-30 | 1999-03-30 | 照明装置及びその照明装置を用いた液晶表示装置 |
JP11/88757 | 1999-03-30 | ||
JP13384199A JP3533108B2 (ja) | 1999-05-14 | 1999-05-14 | 照明装置及びその照明装置を用いた液晶表示装置 |
JP11/133841 | 1999-05-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000060280A1 true WO2000060280A1 (fr) | 2000-10-12 |
Family
ID=26430105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2000/001570 WO2000060280A1 (fr) | 1999-03-30 | 2000-03-15 | Illuminateur et affichage a cristaux liquides comprenant cet illuminateur |
Country Status (6)
Country | Link |
---|---|
US (1) | US6629764B1 (ja) |
EP (1) | EP1174659A4 (ja) |
KR (1) | KR100498734B1 (ja) |
CN (1) | CN1123797C (ja) |
TW (1) | TW466371B (ja) |
WO (1) | WO2000060280A1 (ja) |
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- 2000-03-15 WO PCT/JP2000/001570 patent/WO2000060280A1/ja active IP Right Grant
- 2000-03-15 EP EP00909645A patent/EP1174659A4/en not_active Ceased
- 2000-03-15 KR KR10-2001-7012572A patent/KR100498734B1/ko not_active IP Right Cessation
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Also Published As
Publication number | Publication date |
---|---|
KR100498734B1 (ko) | 2005-07-01 |
TW466371B (en) | 2001-12-01 |
CN1123797C (zh) | 2003-10-08 |
EP1174659A1 (en) | 2002-01-23 |
CN1345406A (zh) | 2002-04-17 |
KR20020015033A (ko) | 2002-02-27 |
US6629764B1 (en) | 2003-10-07 |
EP1174659A4 (en) | 2007-04-11 |
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