US20010050847A1 - Spread illuminating apparatus - Google Patents
Spread illuminating apparatus Download PDFInfo
- Publication number
- US20010050847A1 US20010050847A1 US09/769,472 US76947201A US2001050847A1 US 20010050847 A1 US20010050847 A1 US 20010050847A1 US 76947201 A US76947201 A US 76947201A US 2001050847 A1 US2001050847 A1 US 2001050847A1
- Authority
- US
- United States
- Prior art keywords
- light
- transparent substrate
- conductive member
- frame
- illuminating apparatus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
- G02B6/0086—Positioning aspects
- G02B6/0091—Positioning aspects of the light source relative to 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
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0028—Light guide, e.g. taper
-
- 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
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0031—Reflecting element, sheet or layer
-
- 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
- G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
- G02B6/0086—Positioning aspects
-
- 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
- G02B6/0035—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
- the present invention relates to a spread illuminating apparatus used as an illuminating means for signboards, various kinds of reflection-type display devices and the like, and more particularly, to a spread illuminating apparatus used as an illuminating means for a reflection-type liquid crystal display device.
- a liquid crystal display apparatus which is characterized by being thin, small in occupied volume and lightweight, is used for many kinds of electric appliances such as a portable telephone, a personal computer or the like. Since a liquid crystal of the liquid crystal display device does not emit light by itself, when the liquid crystal display device is used in a dark place where sunlight or room light is not sufficiently available, a separate illuminating apparatus for lighting the liquid crystal is required besides the liquid crystal display device. Accordingly, it is desirable that such an illuminating apparatus is also small in size and low in power consumption. In order to attain this, light from the illuminating apparatus must be efficiently used.
- a conventional spread illuminating apparatus to answer such a demand is shown in FIG. 10 as an example.
- a spread illuminating apparatus 1 ′ generally comprises a transparent substrate 2 formed of a light-transmissible material and a light source 5 disposed close to an end surface 8 of the transparent substrate 2 .
- the spread illuminating apparatus 1 ′ makes light beams emitted from the light source 5 enter the transparent substrate 2 to light a liquid crystal display device (not shown in the figure) disposed under the transparent substrate 2 .
- the light source 5 comprises a long plate-like light conductive member 3 formed of a transparent material and a spot-like light source (for example, light emitting diode) 4 disposed at an end of the light conductive member 3 and mounted on a flexible printed circuit board 6 .
- the light conductive member 3 is formed in a so-called wedge-shape, in which its thickness gradually decreases as it gets away from the spot-like light source 4 .
- the light conductive member 3 is provided with an optical path conversion means 12 .
- the optical path conversion means 12 is formed on a surface opposite to a surface 9 facing the end surface 8 of the transparent substrate 2 , and comprises grooves 10 triangular in section and plane portions 11 adjacent to the grooves 10 .
- Light beams emitted from the spot-like light source 4 disposed at the end of the light conductive member 3 are adapted to enter substantially uniformly the end surface 8 of the transparent substrate 2 thanks to the wedge-shaped light conductive member 3 and the optical path conversion means 12 .
- the light conductive member 3 is disposed at a predetermined distance from the end surface 8 of the transparent substrate 2 in such a manner that the surface 9 of the light conductive member 3 is aligned to the end surface 8 of the transparent substrate 2 .
- a frame 13 is provided around the light conductive member 3 so that the light beams emitted from the spot-like light source 4 can enter efficiently the transparent substrate 2 .
- the frame 13 is formed substantially in C-shape and covers longitudinal surfaces of the light conductive member 3 except the surface 9 facing the transparent substrate 2 .
- the frame 13 is disposed in such a manner that a part of an upper plate inner surface 14 and a part of a lower plate inner surface 15 of the frame 13 overlap a part of the transparent substrate 2 at the end surface 8 side (see FIG. 12).
- the transparent substrate 2 is formed in a so-called wedge-shape, in which its thickness gradually decreases as it gets away far from the end surface 8 . Further, a light reflection pattern 19 is formed on an upper surface 16 of the transparent substrate 2 .
- the light reflection pattern 19 comprises grooves 17 triangular in section and plane portions 18 adjacent to the grooves 17 . Then, light beams coming from the light conductive member 3 are reflected uniformly on the whole surface of the transparent substrate 2 irrespective of the distance from the light conductive member 3 and illuminate the liquid crystal display device (not shown) disposed under the transparent substrate 2 .
- a reflection preventive film 20 is attached to a lower surface of the transparent substrate 2 . Even when light from the light source 5 is not used, that is, sunlight, room light or the like is used, the light does not cause diffused reflection inside the transparent substrate 2 because of the reflection preventive film 20 , and illuminates the liquid crystal display device disposed under the transparent substrate 2 . Thus, good images can be displayed on a liquid crystal screen.
- the areas of the opposing surfaces of the transparent substrate 2 and the light conductive member 3 are set equal to each other in order that the light beams emitted from the spot-like light source 4 are most efficiently transmitted into the transparent substrate 2 .
- the light beams can be most efficiently transmitted from the exit surface 9 to the incident surface 8 .
- the reflection preventive film 20 is attached to the lower surface of the transparent substrate 2 , when the dimension of the incident surface 8 and the dimension of the exit surface 9 are set equal to each other, the thickness of the transparent substrate 2 turns out to be larger than the thickness of the light conductive member 3 by the thickness t of the reflection preventive film 20 (see FIG. 11). In this state, if the light conductive member 3 and the transparent substrate 2 are simply set in the frame 13 , the exit surface 9 shifts off (slides down) relative to the incident surface 8 by the thickness t of the reflection preventive film 20 as shown in FIG. 12.
- the present invention has been made in view of the above, and an object of the present invention is therefore to provide a spread illuminating apparatus in which a light source (light conductive member) can be positioned accurately and easily in the thickness direction relative to a transparent substrate thereby presenting a good liquid crystal display.
- a spread illuminating apparatus comprising a bar-like light source disposed close to an end surface of a transparent substrate formed of a light-transmissible material, characterized in that a frame is provided in such a manner as to cover the bar-like light source and a portion of the transparent substrate to which the bar-like light source is disposed close, and that the frame is provided with a positioning means for determining the position of the bar-like light source relative to the transparent substrate in the thickness direction.
- the end surface of the transparent substrate and the surface of the bar-like light source, which face each other, are disposed in such a manner that the surfaces oppose each other at a predetermined distance in an exactly matching position due to the positioning means.
- light is transmitted with a high efficiency.
- the positioning in the thickness direction refers to the positioning of the end surface of the transparent substrate and the surface of the bar-like light source, which face each other, in the short-side direction.
- the spread illuminating apparatus is characterized in that bent springs are provided as the positioning means.
- the bent springs are disposed on an inner surface of the frame where the bar-like light source is to sit and the bar-like light source in the frame is pushed up in the thickness direction and fixedly positioned at a place where the surface of the bar-like light source coincides with the end surface of the transparent substrate, whereby the light from the light source is transmitted to the transparent substrate efficiently.
- the spread illuminating apparatus is characterized in that wrinkles are provided as the positioning means.
- the wrinkles provided as the positioning means the surface of the bar-like light source and the end surface of the transparent substrate can coincide accurately with each other simply by setting the bar-like light source into the frame.
- the light from the light source can efficiently be transmitted to the transparent substrate.
- the spread illuminating apparatus of the present invention is characterized in that the frame is bent to have a step as the positioning means. Due to the step provided on the frame, the positional relationship between the bar-like light source and the transparent substrate both disposed in the frame is exactly determined.
- the spread illuminating apparatus is characterized in that a spacer is provided as the positioning means on an inner surface of the frame where the bar-like light source is to sit.
- the spacer can be with an arbitrary thickness, and due to the spacer the positional relationship between the bar-like light source and the transparent substrate is accurately determined.
- FIG. 1 is an exploded perspective view showing an embodiment of a spread illuminating apparatus according to the present invention
- FIG. 2 is a view showing an example of a positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 3 is a top view of the positioning means in FIG. 2;
- FIG. 4 is a view showing the positional relationship between a light conductive member and a transparent substrate, which is determined by the positioning means in FIG. 2;
- FIG. 5 is a view showing another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 6 is a top view of the positioning means in FIG. 5;
- FIG. 7 is a view showing still another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 8 is a view showing still another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 9 is a view showing an arrangement of the positioning means in FIG. 8;
- FIG. 10 is an exploded perspective view showing a conventional spread illuminating apparatus
- FIG. 11 is a view showing the difference in thickness between the light conductive member and the transparent substrate of the spread illuminating apparatus in FIG. 10;
- FIG. 12 is a view showing the positional relationship between the light conductive member and the transparent substrate put together within a frame in FIG. 10.
- FIG. 1 is a view showing an embodiment of a spread illuminating apparatus according to the present invention.
- a spread illuminating apparatus 1 is constituted by putting together a transparent substrate 2 , a light source 5 comprising a light conductive member 3 and a spot-like light source (for example, a light emitting diode) 4 , a frame 13 which covers the light conductive member 3 , and a reflection preventive film 20 attached to the lower surface of the transparent substrate 2 (the respective components to be put together in accordance with the directions indicated by arrows in the figure).
- the light conductive member 3 is formed in a so-called wedge-shape, in which the thickness thereof gradually decreases as it gets farther from the spot-like light source 4 . Further, an optical path conversion means 12 is formed on a surface of the light conductive member 3 . Such a structure enables light beams emitted from the spot-like light source 4 and entering the light conductive member 3 to be uniformly transmitted into the transparent substrate 2 irrespective of the distance from the spot-like light source 4 . Further, the transparent substrate 2 is also formed in a so-called wedge-shape, in which the thickness thereof gradually decreases.
- a light reflection pattern 19 which reflects light beams emitted from the light conductive member 3 and made incident on the transparent substrate 2 , is formed on the upper surface of the transparent substrate 2 .
- the light beams made incident on the transparent substrate 2 can illuminate a liquid crystal display apparatus (not shown) disposed under the transparent substrate 2 uniformly from the entire surface of the transparent substrate 2 .
- the frame 13 is a metal plate processed by bending. A film evaporated with metal such as silver (not shown) is attached to the inner surface of the frame 13 in order to reflect efficiently light beams emitted from the light conductive member.
- the depth of the frame 13 that covers the light conductive member 3 is larger than the maximum width of the light conductive member 3 formed in a wedge-shape, and parts of an upper plate inner surface 14 and a lower plate inner surface 15 of the frame 13 are to cover the end portion of the transparent substrate 2 when the spread illuminating apparatus 1 is assembled.
- the frame 13 is provided with a claw 22 respectively at each of the longitudinal end of the frame 13 .
- the claw 22 is a positioning means for determining the position of the light conductive member 3 relative to the transparent substrate 2 in the longitudinal direction, and is integrally formed with the frame 13 .
- the claw 22 is positioned in such a manner as to partially overlap the transparent substrate 2 .
- An exit surface 9 of the light conductive member 3 and an incident surface 8 of the transparent substrate 2 are formed to have an equal area, and both the long sides and the short sides of the exit and incident surfaces are equal to each other in length, respectively. Therefore, when the exit surface 9 and the incident surface 8 are disposed in such a manner as to exactly overlap each other at a predetermined distance from each other, light can be most efficiently transmitted.
- the dimension h (distance between the upper plate inner surface 14 and the lower plate inner surface 15 ) of the frame 13 is set to be equal to the dimension which includes the thickness of the reflection preventive film 20 in addition to the length of the short side of the incident surface 8 of the transparent substrate 2 .
- the dimension h of the frame 13 is larger than the length of the short side of the exit surface 9 of the light conductive member 3 by the thickness of the reflection preventive film 20 .
- the lower plate inner surface 15 of the frame 13 is provided with positioning means 25 that shift the position of the light conductive member 3 disposed in the frame 13 by the thickness of the reflection preventive film 20 toward the upper plate inner surface 14 (direction of the light source thickness) when the spread illuminating apparatus 1 is assembled.
- the positioning means embodiment of which is described hereinafter with reference to example, hold fixedly the exit surface 9 and the incident surface 8 at the same position in the direction of the light source thickness. Thus, light can be transmitted with the best efficiency.
- FIGS. 2 to 4 show an example in which bent springs 26 are provided on the lower plate inner surface 15 of the frame 13 as the positioning means.
- FIG. 2 shows the inside of the frame 13 of the spread illuminating apparatus 1 assembled as seen from the exit surface 9 of the light conductive member 3 .
- a plurality of bent springs 26 are disposed on the lower plate inner surface 15 and push up the light conductive member 3 off the lower plate inner surface 15 toward the upper plate inner surface 14 by the thickness t of the reflection preventive film 20 .
- FIG. 3 shows the lower plate inner surface 15 of the frame 13 as seen from the upper plate inner surface 14 side.
- a cut-away 27 is provided to form each of the bent springs 26 .
- the bent springs 26 are provided at a position close to a back plate inner surface 23 of the frame 13 (to keep the bent springs 26 clear of the transparent substrate 2 ) in order to push up only the light conductive member 3 when the bent springs 26 are raised.
- the bent springs 26 can be regulated in bending height from the outside by pushing in using a tool such as a screwdriver after the spread illuminating apparatus 1 is assembled complete with the frame 13 .
- FIG. 4 shows the positional relationship between the light conductive member 3 pushed up by the bent springs 26 and the transparent substrate 2 .
- the light conductive member 3 pushed up by the bent springs 26 is shifted toward the upper plate inner surface 14 relative to the transparent substrate 2 by the thickness of the reflection preventive film 20 so that the exit surface 9 and the incident surface 8 overlap exactly each other.
- FIGS. 5 and 6 show an example in which protrusions (for example, wrinkles) 28 are provided on the lower plate inner surface 15 of the frame 13 as the positioning means.
- a plurality of protrusions 28 are formed by a process called wrinkling when the frame 13 is produced.
- the height of the protrusions 28 is set to be equal to the thickness t of the reflection preventive film 20 so that when the light conductive member 3 is assembled in the frame 13 , the protrusions 28 push up the light conductive member 3 off the lower plate inner surface 15 toward the upper plate inner surface 14 by the height of the wrinkles 28 , that is, by the thickness t of the reflection preventive film 20 .
- the exit surface 9 of the light conductive member 3 and the incident surface 8 of the transparent substrate 2 are fixedly held at the same position in the direction of the light source thickness, and therefore light can be transmitted with the best efficiency.
- the wrinkles 28 are disposed close to the back plate inner surface 23 of the frame 13 for the same reason as in case of the bent springs 26 (see FIG. 6).
- FIG. 7 shows an example in which a step 29 is provided on the lower plate inner surface 15 of the frame 13 as the positioning means.
- the step 29 is formed on the lower plate inner surface 15 by bending the lower plate of the frame 13 at two places.
- the step 29 is formed during the process of bending the frame 13 in accordance with the size of the light conductive member 3 , the thickness of the reflection preventive film 20 , or the like.
- the height of the step 29 is made to be equal to the thickness t of the reflection preventive film 20 .
- the light conductive member 3 is pushed up due to the step 29 toward the upper plate inner surface 14 relative to the transparent substrate 2 .
- the exit surface 9 of the light conductive member 3 and the incident surface 8 of the transparent substrate 2 are fixedly held at the same position relative to the direction of the light source thickness, and therefore light can be transmitted with the best efficiency.
- FIGS. 8 and 9 show an example in which a spacer 30 is provided on the lower plate inner surface 15 of the frame 13 as the positioning means.
- the spacer 30 has a thickness equal to the thickness t of the reflection preventive film 20 .
- the light conductive member 3 is pushed up by the thickness of the spacer 30 relative to the transparent substrate 2 , that is, by the thickness t of the reflection preventive film 20 . Therefore, the exit surface 9 and the incident surface 8 are fixedly held at the same position in the direction of the light source thickness.
- the frame 13 does not need any extra processing work in addition to the existing bending.
- the spacer 30 having the thickness t is adapted to cover the entire lower surface of the light conductive member 3 in this example, but it suffices if the light conductive member 3 is pushed up off the lower plate inner surface 15 by the thickness t of the reflection preventive film 20 . Accordingly, provision of a plurality of small spacers will serve the purpose.
- the spread illuminating apparatus of the present invention ensures that the bar-like light source can be properly positioned relative to the transparent substrate in the direction of their thickness. Further, when the positioning means is formed on the frame in advance, the number of components can be prevented from increasing, and also the spread illuminating apparatus can be easily assembled. When the positioning means such as a spacer is attached to the frame, the existing frame can be used as it is since there is no need to additionally process the frame. Thus, the increase in cost can be suppressed. Furthermore, the exit surface of the light conductive member constituting the light source and the incident surface of the transparent substrate may be fixedly held at the same position in the direction of the light source thickness.
- the exit surface of the light conductive member does not overlap any portion of the reflection preventive film that is attached to the lower surface of the transparent substrate. Therefore, a defect that the end portion of the reflection preventive film is reflected in the liquid crystal display screen, which leads to unevenness in brightness on the screen, can be prevented.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to a spread illuminating apparatus used as an illuminating means for signboards, various kinds of reflection-type display devices and the like, and more particularly, to a spread illuminating apparatus used as an illuminating means for a reflection-type liquid crystal display device.
- 2. Description of the Related Art
- A liquid crystal display apparatus, which is characterized by being thin, small in occupied volume and lightweight, is used for many kinds of electric appliances such as a portable telephone, a personal computer or the like. Since a liquid crystal of the liquid crystal display device does not emit light by itself, when the liquid crystal display device is used in a dark place where sunlight or room light is not sufficiently available, a separate illuminating apparatus for lighting the liquid crystal is required besides the liquid crystal display device. Accordingly, it is desirable that such an illuminating apparatus is also small in size and low in power consumption. In order to attain this, light from the illuminating apparatus must be efficiently used. A conventional spread illuminating apparatus to answer such a demand is shown in FIG. 10 as an example.
- As shown in the figure, a spread
illuminating apparatus 1′ generally comprises atransparent substrate 2 formed of a light-transmissible material and alight source 5 disposed close to anend surface 8 of thetransparent substrate 2. The spreadilluminating apparatus 1′ makes light beams emitted from thelight source 5 enter thetransparent substrate 2 to light a liquid crystal display device (not shown in the figure) disposed under thetransparent substrate 2. - The
light source 5 comprises a long plate-like lightconductive member 3 formed of a transparent material and a spot-like light source (for example, light emitting diode) 4 disposed at an end of the lightconductive member 3 and mounted on a flexible printedcircuit board 6. The lightconductive member 3 is formed in a so-called wedge-shape, in which its thickness gradually decreases as it gets away from the spot-like light source 4. Further, the lightconductive member 3 is provided with an optical path conversion means 12. The optical path conversion means 12 is formed on a surface opposite to asurface 9 facing theend surface 8 of thetransparent substrate 2, and comprisesgrooves 10 triangular in section andplane portions 11 adjacent to thegrooves 10. Light beams emitted from the spot-like light source 4 disposed at the end of the lightconductive member 3 are adapted to enter substantially uniformly theend surface 8 of thetransparent substrate 2 thanks to the wedge-shaped lightconductive member 3 and the optical path conversion means 12. Note that the lightconductive member 3 is disposed at a predetermined distance from theend surface 8 of thetransparent substrate 2 in such a manner that thesurface 9 of the lightconductive member 3 is aligned to theend surface 8 of thetransparent substrate 2. - A
frame 13 is provided around the lightconductive member 3 so that the light beams emitted from the spot-like light source 4 can enter efficiently thetransparent substrate 2. Theframe 13 is formed substantially in C-shape and covers longitudinal surfaces of the lightconductive member 3 except thesurface 9 facing thetransparent substrate 2. Theframe 13 is disposed in such a manner that a part of an upper plateinner surface 14 and a part of a lower plateinner surface 15 of theframe 13 overlap a part of thetransparent substrate 2 at theend surface 8 side (see FIG. 12). A hard plastic to which a film evaporated with metal such as silver, a white-color film or the like is attached, or a bent metal plate such as an aluminum plate or a stainless plate is pasted on the sides of theframe 13 that face the light conductive member 3 (inner surfaces). - The
transparent substrate 2 is formed in a so-called wedge-shape, in which its thickness gradually decreases as it gets away far from theend surface 8. Further, alight reflection pattern 19 is formed on anupper surface 16 of thetransparent substrate 2. Thelight reflection pattern 19 comprisesgrooves 17 triangular in section andplane portions 18 adjacent to thegrooves 17. Then, light beams coming from the lightconductive member 3 are reflected uniformly on the whole surface of thetransparent substrate 2 irrespective of the distance from the lightconductive member 3 and illuminate the liquid crystal display device (not shown) disposed under thetransparent substrate 2. - Moreover, a reflection
preventive film 20 is attached to a lower surface of thetransparent substrate 2. Even when light from thelight source 5 is not used, that is, sunlight, room light or the like is used, the light does not cause diffused reflection inside thetransparent substrate 2 because of the reflectionpreventive film 20, and illuminates the liquid crystal display device disposed under thetransparent substrate 2. Thus, good images can be displayed on a liquid crystal screen. - By the way, in the spread
illuminating apparatus 1′ structured as described above, it is desirable that the areas of the opposing surfaces of thetransparent substrate 2 and the lightconductive member 3 are set equal to each other in order that the light beams emitted from the spot-like light source 4 are most efficiently transmitted into thetransparent substrate 2. In other words, when the dimension of the end surface (incident surface) 8 of thetransparent substrate 2 and the dimension of the surface (exit surface) 9 of the lightconductive member 3 that faces theincident surface 8 are equal to each other, the light beams can be most efficiently transmitted from theexit surface 9 to theincident surface 8. However, because the reflectionpreventive film 20 is attached to the lower surface of thetransparent substrate 2, when the dimension of theincident surface 8 and the dimension of theexit surface 9 are set equal to each other, the thickness of thetransparent substrate 2 turns out to be larger than the thickness of the lightconductive member 3 by the thickness t of the reflection preventive film 20 (see FIG. 11). In this state, if the lightconductive member 3 and thetransparent substrate 2 are simply set in theframe 13, theexit surface 9 shifts off (slides down) relative to theincident surface 8 by the thickness t of the reflectionpreventive film 20 as shown in FIG. 12. Therefore, it does not happen that light beams emitted from theexit surface 9 enter most efficiently theincident surface 8, and a part of the light beams emitted from theexit surface 9 enters the reflectionpreventive film 20. If the light beams enter the reflectionpreventive film 20, the end portion of the reflectionpreventive film 20 is reflected in the liquid crystal screen thereby generating an unevenness in brightness. Accordingly, in order to transmit light in the most efficient manner, theexit surface 9 and theincident surface 8 must face each other in an accurately matching position. - The present invention has been made in view of the above, and an object of the present invention is therefore to provide a spread illuminating apparatus in which a light source (light conductive member) can be positioned accurately and easily in the thickness direction relative to a transparent substrate thereby presenting a good liquid crystal display.
- In order to solve the above problem, according to a first aspect of the present invention, there is provided a spread illuminating apparatus comprising a bar-like light source disposed close to an end surface of a transparent substrate formed of a light-transmissible material, characterized in that a frame is provided in such a manner as to cover the bar-like light source and a portion of the transparent substrate to which the bar-like light source is disposed close, and that the frame is provided with a positioning means for determining the position of the bar-like light source relative to the transparent substrate in the thickness direction. According to the present invention, the end surface of the transparent substrate and the surface of the bar-like light source, which face each other, are disposed in such a manner that the surfaces oppose each other at a predetermined distance in an exactly matching position due to the positioning means. Thus, light is transmitted with a high efficiency.
- Here, the positioning in the thickness direction refers to the positioning of the end surface of the transparent substrate and the surface of the bar-like light source, which face each other, in the short-side direction.
- Further, in order to solve the above problem, according to a second aspect of the present invention, the spread illuminating apparatus is characterized in that bent springs are provided as the positioning means. The bent springs are disposed on an inner surface of the frame where the bar-like light source is to sit and the bar-like light source in the frame is pushed up in the thickness direction and fixedly positioned at a place where the surface of the bar-like light source coincides with the end surface of the transparent substrate, whereby the light from the light source is transmitted to the transparent substrate efficiently.
- Moreover, in order to solve the above problem, according to a third aspect of the present invention, the spread illuminating apparatus is characterized in that wrinkles are provided as the positioning means. With the wrinkles provided as the positioning means, the surface of the bar-like light source and the end surface of the transparent substrate can coincide accurately with each other simply by setting the bar-like light source into the frame. Thus, the light from the light source can efficiently be transmitted to the transparent substrate.
- In addition, in order to solve the above problem, according to a fourth aspect of the present invention, the spread illuminating apparatus of the present invention is characterized in that the frame is bent to have a step as the positioning means. Due to the step provided on the frame, the positional relationship between the bar-like light source and the transparent substrate both disposed in the frame is exactly determined.
- Furthermore, in order to solve the above problem, according to a fifth aspect of the present invention, the spread illuminating apparatus is characterized in that a spacer is provided as the positioning means on an inner surface of the frame where the bar-like light source is to sit. The spacer can be with an arbitrary thickness, and due to the spacer the positional relationship between the bar-like light source and the transparent substrate is accurately determined.
- In the accompanying drawings:
- FIG. 1 is an exploded perspective view showing an embodiment of a spread illuminating apparatus according to the present invention;
- FIG. 2 is a view showing an example of a positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 3 is a top view of the positioning means in FIG. 2;
- FIG. 4 is a view showing the positional relationship between a light conductive member and a transparent substrate, which is determined by the positioning means in FIG. 2;
- FIG. 5 is a view showing another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 6 is a top view of the positioning means in FIG. 5;
- FIG. 7 is a view showing still another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 8 is a view showing still another example of the positioning means of the spread illuminating apparatus in FIG. 1;
- FIG. 9 is a view showing an arrangement of the positioning means in FIG. 8;
- FIG. 10 is an exploded perspective view showing a conventional spread illuminating apparatus;
- FIG. 11 is a view showing the difference in thickness between the light conductive member and the transparent substrate of the spread illuminating apparatus in FIG. 10; and
- FIG. 12 is a view showing the positional relationship between the light conductive member and the transparent substrate put together within a frame in FIG. 10.
- Hereinafter, preferred embodiments of a spread illuminating apparatus according to the present invention will be described referring to the accompanying drawings.
- It is to be noted that parts identical with or equivalent to those in the conventional art are designated by the same numerals and the detailed description thereof is omitted.
- FIG. 1 is a view showing an embodiment of a spread illuminating apparatus according to the present invention.
- As shown in FIG. 1, a
spread illuminating apparatus 1 is constituted by putting together atransparent substrate 2, alight source 5 comprising a lightconductive member 3 and a spot-like light source (for example, a light emitting diode) 4, aframe 13 which covers the lightconductive member 3, and a reflectionpreventive film 20 attached to the lower surface of the transparent substrate 2 (the respective components to be put together in accordance with the directions indicated by arrows in the figure). - The light
conductive member 3 is formed in a so-called wedge-shape, in which the thickness thereof gradually decreases as it gets farther from the spot-like light source 4. Further, an optical path conversion means 12 is formed on a surface of the lightconductive member 3. Such a structure enables light beams emitted from the spot-like light source 4 and entering the lightconductive member 3 to be uniformly transmitted into thetransparent substrate 2 irrespective of the distance from the spot-like light source 4. Further, thetransparent substrate 2 is also formed in a so-called wedge-shape, in which the thickness thereof gradually decreases. Alight reflection pattern 19, which reflects light beams emitted from the lightconductive member 3 and made incident on thetransparent substrate 2, is formed on the upper surface of thetransparent substrate 2. In accordance with such structures, the light beams made incident on thetransparent substrate 2 can illuminate a liquid crystal display apparatus (not shown) disposed under thetransparent substrate 2 uniformly from the entire surface of thetransparent substrate 2. In addition, theframe 13 is a metal plate processed by bending. A film evaporated with metal such as silver (not shown) is attached to the inner surface of theframe 13 in order to reflect efficiently light beams emitted from the light conductive member. The depth of theframe 13 that covers the lightconductive member 3 is larger than the maximum width of the lightconductive member 3 formed in a wedge-shape, and parts of an upper plateinner surface 14 and a lower plateinner surface 15 of theframe 13 are to cover the end portion of thetransparent substrate 2 when thespread illuminating apparatus 1 is assembled. - Further, the
frame 13 is provided with aclaw 22 respectively at each of the longitudinal end of theframe 13. Theclaw 22 is a positioning means for determining the position of the lightconductive member 3 relative to thetransparent substrate 2 in the longitudinal direction, and is integrally formed with theframe 13. When thespread illuminating apparatus 1 is assembled, theclaw 22 is positioned in such a manner as to partially overlap thetransparent substrate 2. - An
exit surface 9 of the lightconductive member 3 and anincident surface 8 of thetransparent substrate 2 are formed to have an equal area, and both the long sides and the short sides of the exit and incident surfaces are equal to each other in length, respectively. Therefore, when theexit surface 9 and theincident surface 8 are disposed in such a manner as to exactly overlap each other at a predetermined distance from each other, light can be most efficiently transmitted. Note that the dimension h (distance between the upper plateinner surface 14 and the lower plate inner surface 15) of theframe 13 is set to be equal to the dimension which includes the thickness of the reflectionpreventive film 20 in addition to the length of the short side of theincident surface 8 of thetransparent substrate 2. Thus, the dimension h of theframe 13 is larger than the length of the short side of theexit surface 9 of the lightconductive member 3 by the thickness of the reflectionpreventive film 20. Moreover, the lower plateinner surface 15 of theframe 13 is provided with positioning means 25 that shift the position of the lightconductive member 3 disposed in theframe 13 by the thickness of the reflectionpreventive film 20 toward the upper plate inner surface 14 (direction of the light source thickness) when thespread illuminating apparatus 1 is assembled. The positioning means, embodiment of which is described hereinafter with reference to example, hold fixedly theexit surface 9 and theincident surface 8 at the same position in the direction of the light source thickness. Thus, light can be transmitted with the best efficiency. - FIGS.2 to 4 show an example in which bent springs 26 are provided on the lower plate
inner surface 15 of theframe 13 as the positioning means. - FIG. 2 shows the inside of the
frame 13 of thespread illuminating apparatus 1 assembled as seen from theexit surface 9 of the lightconductive member 3. A plurality of bent springs 26 (two in this case) are disposed on the lower plateinner surface 15 and push up the lightconductive member 3 off the lower plateinner surface 15 toward the upper plateinner surface 14 by the thickness t of the reflectionpreventive film 20. FIG. 3 shows the lower plateinner surface 15 of theframe 13 as seen from the upper plateinner surface 14 side. A cut-away 27 is provided to form each of the bent springs 26. The bent springs 26 are provided at a position close to a back plateinner surface 23 of the frame 13 (to keep thebent springs 26 clear of the transparent substrate 2) in order to push up only the lightconductive member 3 when thebent springs 26 are raised. The bent springs 26 can be regulated in bending height from the outside by pushing in using a tool such as a screwdriver after thespread illuminating apparatus 1 is assembled complete with theframe 13. FIG. 4 shows the positional relationship between the lightconductive member 3 pushed up by the bent springs 26 and thetransparent substrate 2. The lightconductive member 3 pushed up by the bent springs 26 is shifted toward the upper plateinner surface 14 relative to thetransparent substrate 2 by the thickness of the reflectionpreventive film 20 so that theexit surface 9 and theincident surface 8 overlap exactly each other. - FIGS. 5 and 6 show an example in which protrusions (for example, wrinkles)28 are provided on the lower plate
inner surface 15 of theframe 13 as the positioning means. - A plurality of protrusions28 (two in this case) are formed by a process called wrinkling when the
frame 13 is produced. The height of theprotrusions 28 is set to be equal to the thickness t of the reflectionpreventive film 20 so that when the lightconductive member 3 is assembled in theframe 13, theprotrusions 28 push up the lightconductive member 3 off the lower plateinner surface 15 toward the upper plateinner surface 14 by the height of thewrinkles 28, that is, by the thickness t of the reflectionpreventive film 20. Thus, theexit surface 9 of the lightconductive member 3 and theincident surface 8 of thetransparent substrate 2 are fixedly held at the same position in the direction of the light source thickness, and therefore light can be transmitted with the best efficiency. Thewrinkles 28 are disposed close to the back plateinner surface 23 of theframe 13 for the same reason as in case of the bent springs 26 (see FIG. 6). - FIG. 7 shows an example in which a
step 29 is provided on the lower plateinner surface 15 of theframe 13 as the positioning means. - The
step 29 is formed on the lower plateinner surface 15 by bending the lower plate of theframe 13 at two places. Thestep 29 is formed during the process of bending theframe 13 in accordance with the size of the lightconductive member 3, the thickness of the reflectionpreventive film 20, or the like. The height of thestep 29 is made to be equal to the thickness t of the reflectionpreventive film 20. The lightconductive member 3 is pushed up due to thestep 29 toward the upper plateinner surface 14 relative to thetransparent substrate 2. Thus, theexit surface 9 of the lightconductive member 3 and theincident surface 8 of thetransparent substrate 2 are fixedly held at the same position relative to the direction of the light source thickness, and therefore light can be transmitted with the best efficiency. - FIGS. 8 and 9 show an example in which a
spacer 30 is provided on the lower plateinner surface 15 of theframe 13 as the positioning means. - The
spacer 30 has a thickness equal to the thickness t of the reflectionpreventive film 20. Thus, the lightconductive member 3 is pushed up by the thickness of thespacer 30 relative to thetransparent substrate 2, that is, by the thickness t of the reflectionpreventive film 20. Therefore, theexit surface 9 and theincident surface 8 are fixedly held at the same position in the direction of the light source thickness. Unlike the other positioning means described above, theframe 13 does not need any extra processing work in addition to the existing bending. Thespacer 30 having the thickness t is adapted to cover the entire lower surface of the lightconductive member 3 in this example, but it suffices if the lightconductive member 3 is pushed up off the lower plateinner surface 15 by the thickness t of the reflectionpreventive film 20. Accordingly, provision of a plurality of small spacers will serve the purpose. - From the above, the spread illuminating apparatus of the present invention ensures that the bar-like light source can be properly positioned relative to the transparent substrate in the direction of their thickness. Further, when the positioning means is formed on the frame in advance, the number of components can be prevented from increasing, and also the spread illuminating apparatus can be easily assembled. When the positioning means such as a spacer is attached to the frame, the existing frame can be used as it is since there is no need to additionally process the frame. Thus, the increase in cost can be suppressed. Furthermore, the exit surface of the light conductive member constituting the light source and the incident surface of the transparent substrate may be fixedly held at the same position in the direction of the light source thickness. Thus, the exit surface of the light conductive member does not overlap any portion of the reflection preventive film that is attached to the lower surface of the transparent substrate. Therefore, a defect that the end portion of the reflection preventive film is reflected in the liquid crystal display screen, which leads to unevenness in brightness on the screen, can be prevented.
Claims (5)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000030538A JP3829270B2 (en) | 2000-02-08 | 2000-02-08 | Surface lighting device |
JP2000-030538 | 2000-02-08 | ||
JP2000-30538 | 2000-02-08 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010050847A1 true US20010050847A1 (en) | 2001-12-13 |
US6443584B2 US6443584B2 (en) | 2002-09-03 |
Family
ID=18555536
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/769,472 Expired - Fee Related US6443584B2 (en) | 2000-02-08 | 2001-01-26 | Spread illuminating apparatus with means for positioning a bar-like light source |
Country Status (2)
Country | Link |
---|---|
US (1) | US6443584B2 (en) |
JP (1) | JP3829270B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080117361A1 (en) * | 2006-11-21 | 2008-05-22 | Hyo-Suck Chun | Liquid crystal display |
US20160091657A1 (en) * | 2013-09-09 | 2016-03-31 | Shenzhen Tcl New Technology Co., Ltd. | Backlight module |
US20160109634A1 (en) * | 2014-10-15 | 2016-04-21 | Minebea Co., Ltd. | Spread illuminating apparatus |
KR20190091310A (en) * | 2016-11-30 | 2019-08-05 | 택토텍 오와이 | Light emitting structure and method of manufacturing the same |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4130100B2 (en) * | 2002-07-05 | 2008-08-06 | アルプス電気株式会社 | Surface light emitting device and liquid crystal display device |
US7316484B2 (en) * | 2002-10-09 | 2008-01-08 | Matsushita Electric Industrial Co., Ltd. | Illuminator and projection image display employing it |
AU2002349657A1 (en) * | 2002-11-29 | 2004-06-23 | Fujitsu Limited | Illumination device and liquid crystal display device |
KR100843658B1 (en) | 2006-08-16 | 2008-07-03 | 김장규 | LED lens, back light unit and LCD using a thereof |
KR101313792B1 (en) | 2006-12-07 | 2013-10-01 | 삼성디스플레이 주식회사 | Liquid crystal display |
KR102137137B1 (en) * | 2014-02-11 | 2020-07-27 | 삼성디스플레이 주식회사 | Container of quantum dot bar and backlight unit comprising the same |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3379043B2 (en) * | 1998-06-29 | 2003-02-17 | ミネベア株式会社 | Planar lighting device |
-
2000
- 2000-02-08 JP JP2000030538A patent/JP3829270B2/en not_active Expired - Fee Related
-
2001
- 2001-01-26 US US09/769,472 patent/US6443584B2/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080117361A1 (en) * | 2006-11-21 | 2008-05-22 | Hyo-Suck Chun | Liquid crystal display |
US8031292B2 (en) * | 2006-11-21 | 2011-10-04 | Samsung Electronics Co., Ltd. | Liquid crystal display comprising first and second point light source assemblies wherein a first support substrate is larger than the second support substrate, and a first groove of a lower container is deeper than a second groove |
US20160091657A1 (en) * | 2013-09-09 | 2016-03-31 | Shenzhen Tcl New Technology Co., Ltd. | Backlight module |
US20160109634A1 (en) * | 2014-10-15 | 2016-04-21 | Minebea Co., Ltd. | Spread illuminating apparatus |
US9915772B2 (en) * | 2014-10-15 | 2018-03-13 | Minebea Co., Ltd. | Display back illumination apparatus having compression molded light guide |
KR20190091310A (en) * | 2016-11-30 | 2019-08-05 | 택토텍 오와이 | Light emitting structure and method of manufacturing the same |
KR102604257B1 (en) | 2016-11-30 | 2023-11-20 | 택토텍 오와이 | Light-emitting structure and method of manufacturing the same |
Also Published As
Publication number | Publication date |
---|---|
JP2001222907A (en) | 2001-08-17 |
US6443584B2 (en) | 2002-09-03 |
JP3829270B2 (en) | 2006-10-04 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3875891B2 (en) | Liquid crystal display | |
US7380971B2 (en) | Backlight module | |
EP1975653A1 (en) | Backlight assembly, display apparatus having the same and method for manufacturing the same | |
JPWO2006087863A1 (en) | Area lighting device | |
US8031293B2 (en) | Backlight module with light source holder and liquid crystal display using the same | |
US6443584B2 (en) | Spread illuminating apparatus with means for positioning a bar-like light source | |
JP2007322541A (en) | Illuminator and liquid crystal display | |
US20120075883A1 (en) | Edge-type led backlight moudle | |
US20080137366A1 (en) | Light guide plate and backlight module including the same | |
JP2005208587A (en) | Backlight assembly for liquid crystal display | |
US6811275B2 (en) | Spread illuminating apparatus with plurality of light conductive bars | |
JP2007250458A (en) | Edge input type backlight | |
JP4316979B2 (en) | Liquid crystal display device and method for assembling liquid crystal display device | |
KR100661783B1 (en) | Surface light source device of side light type and liquid crystal display | |
US6517229B2 (en) | Spread illuminating apparatus having heat sink function | |
JP2007059168A (en) | Backlight | |
US7594744B2 (en) | Backlight module | |
JP2003234010A (en) | Flat lighting system | |
KR100724647B1 (en) | Area light device and liquid crystal display apparatus | |
US6530669B2 (en) | Spread illuminating apparatus with a frame having a spring force | |
JP2006302762A (en) | Edge input type backlight and liquid crystal display device | |
JP2004253367A (en) | Backlight unit and liquid crystal display | |
JP2000315414A (en) | Backlight device for display device | |
US6733148B2 (en) | Spread illuminating apparatus with flexible printed circuit | |
JP2005293925A (en) | Luminaire and liquid crystal display |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MINEBEA CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SUZUKI, SHINGO;TOYODA, KOICHI;REEL/FRAME:011495/0953 Effective date: 20010113 |
|
FEPP | Fee payment procedure |
Free format text: PAYER NUMBER DE-ASSIGNED (ORIGINAL EVENT CODE: RMPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20100903 |