GB2269928A - Display - Google Patents
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- Publication number
- GB2269928A GB2269928A GB9316785A GB9316785A GB2269928A GB 2269928 A GB2269928 A GB 2269928A GB 9316785 A GB9316785 A GB 9316785A GB 9316785 A GB9316785 A GB 9316785A GB 2269928 A GB2269928 A GB 2269928A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- liquid crystal
- crystal display
- photoconductor
- reflective
- 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.)
- Withdrawn
Links
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
- G02B6/0013—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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Planar Illumination Modules (AREA)
- Liquid Crystal (AREA)
Abstract
A device for directing light from a light source (12) to a photoconductor (10) of a liquid crystal display, said device comprising a material having a substantially non light-absorbent reflective surface partially surrounding the light source (12) and adapted to direct light into said photoconductor (10). The material of the light guide may be either rigid or flexible. Separate light guides in one and the same liquid crystal display may be interconnected by intermediate bars. The light source is preferably an LED. <IMAGE>
Description
Light guide
The invention relates to a device for directing light tin a liquid crystal display.
In a liquid crystal display the light-producing means, typically light emitting diodes(LEDs), are usually placed at or in the vicinity of the edges of the display. Above the LEDs, or above the entire display, there is fitted a so-called photoconductor, which is usually a means consisting of one or more parallel transparent plates of which the bottom plate is usually white so as to reflect light and the top or upper surface is often made diffuse in order to direct light towards a liquid crystal layer.
Thereby, the photoconductor distributes the light produced by the LEDs evenly over the entire area of the display. On top of the photoconductor there is placed an information transmitting means and on top of this a protective glass or the like.
It is necessary to direct the light produced by the LEDs to the center of the display, since otherwise the light will "escape" to the sides and the display itself will remain almost unlit. The escape of light has so far been prevented by coating with some suitable material, for example by painting, those parts of the photoconductor which surround the LEDs. Such coating of the surrounding of the LEDs has indeed served to prevent the escape of light, but there has also been the disadvantage that the coating has a light-absorbing property, whereby the intensity of the light of the display is weakened.
The present invention addresses the said disadvantage and provides a device for directing light from a light source to a photoconductor of a liquid crystal display, said device comprising a material having a substantially non light-absorbent reflective surface partially surrounding the light source and adapted to direct light into said photoconductor.
The advantage of the present invention is that, light can be aimed with precision at a specific area, whereby the quality of the display is improved and its power requirement is reduced. Materials suitable for the light guide include materials which are themselves reflective and non-absorbing, such as metals, or materials which are themselves non-reflective, such as various plastics and which have the surface facing the source of light coated with a reflective non light-absorbing coating agent. The said material may be either rigid or flexible. If the material is flexible it can be attached using, for example, tape.
In a preferred embodiment the device for directing light is separably coupled to the photoconductor. This has the advantage that it aids manufacture and assembly of a liquid crystal display apparatus.
Suitably, the light guide is made of a rigid material, and if the LEDs are grouped at different edges in the liquid crystal display and constitute areas separate from each other, and are thus protected by separate light guides.
Such light guides may be interconnected by intermediate bars made of a rigid material, to form a continuous piece.
Preferably such light guides and their intermediate bars are from the very beginning machined as one piece. When this piece is attached to the bottom of the display, which usually corresponds to a circuit board, a stable light display without vibration is obtained.
The structure of the light guide according to the invention is shown in greater detail in the following figures.
Figure 1 depicts a top view of the photoconductor.
Figure 2 is a perspective representation of the
photoconductor.
Figure 3 depicts a top view of the photoconductor,
protected by two light guides.
Figure 4 is a perspective representation of one light
guide.
Figure 5 depicts a top view of a continuous piece
which comprises two light guides
interconnected by an intermediate bar.
Figure 6 depicts a side view of the intermediate bar
according to Figure 5.
Figure 7 depicts a side view of a continuous piece
according to Figure 5.
In Figure 1, depicting a photoconductor 10, the sites in which the LEDs are embedded are indicated by reference numeral 12. At points 13 the plate 11 is attached to the bottom of the display.
In Figure 3, the plate 11 of the photoconductor is seen protected by two separate light guides 20. Figure 4 shows in greater detail a light guide in which surface 21 is a curved surface protecting the LEDs 12, and 22 is a level means which can be attached to the plate 11. The LEDs 12 are, of course, not visible through the surface 21 in the devices according Figures 3 and 4; they have been indicated as visible in the figures only for the purpose of elucidating the structure of the light guide. In
Figure 4 light is directed downwards into a photoconductor 10 (not shown) from a side of the photoconductor 10. The surfaces enclosing the light source 12, i.e. the curved surface 21, the side surfaces and the front surface of the light guide 20 in Figure 4 are of reflecting and non light-absorbing material.
Figure 5 depicts a top view of one preferred embodiment of the invention, in which two light guides 20 are interconnected by an intermediate bar 23 to form one piece. The piece can be attached at points 24 to the bottom of the display by, for example, soldering. This piece is preferably made of a continuous, reflective metal sheet. Structures made of sheet metal are economical to manufacture and easy to install.
In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.
The scope of the present disclosure includes any novel feature or combination of features disclosed therein either explicitly or implicitly or any generalisation thereof irrespective of whether or not it relates to the claimed invention or mitigates any or all of the problems addressed by the present invention. The applicant hereby gives notice that new claims may be formulated to such features during prosecution of this application or of any such further application derived therefrom.
Claims (11)
1. A device for directing light from a light source-to a photoconductor of a liquid crystal display, said device comprising a material having a substantially non lightabsorbent reflective surface partially surrounding the light source and adapted to direct light into said photoconductor.
2. A device according to claim 1, separably coupled to the photo conductor.
3. A device according to claim 1 or claim 2, wherein the material is rigid.
4. A device according to any preceding claim, wherein the material comprises a reflective metal.
5. A device according to claim 1, 2 or 3, wherein the material is a metal, a plastics or the like, coated with a substantially non light-absorbent reflective coating.
6. A device according to claim 1 or claim 2, wherein the material is a flexible material, such as tape, ribbon or the like, coated with a substantially non light-absorbent reflective coating.
7. A device according to any of claims 1-4, wherein the device is connected to another light directing device in the same liquid crystal display by means of at least one intermediate bar made of a rigid material, whereupon the separate light directing devices with their at least one intermediate bar constitute a continuous piece which can be attached to the bottom of a liquid crystal display.
8. A device according to claim 7, wherein the intermediate bar comprises a continuous reflective metal sheet.
9. A liquid crystal display apparatus comprising light directing devices according to any of claims 1-4 and at least one intermediate bar interconnecting the light directing devices such that the interconnected light directing devices are capable of being attached as a whole to the liquid crystal display apparatus.
10. A liquid crystal display apparatus according to claim 9, wherein the light directing device and the intermediate bars are made of a continuous, reflective non lightabsorbent metal sheet.
11. A device substantially as hereinbefore described and with reference to the accompanying drawings.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI923695A FI91810C (en) | 1992-08-18 | 1992-08-18 | The light-guide |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9316785D0 GB9316785D0 (en) | 1993-09-29 |
GB2269928A true GB2269928A (en) | 1994-02-23 |
Family
ID=8535727
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9316785A Withdrawn GB2269928A (en) | 1992-08-18 | 1993-08-12 | Display |
Country Status (2)
Country | Link |
---|---|
FI (1) | FI91810C (en) |
GB (1) | GB2269928A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1299154C (en) * | 2002-12-20 | 2007-02-07 | 西铁城电子股份有限公司 | Light conducting board and supporter for it |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1988004789A1 (en) * | 1986-12-20 | 1988-06-30 | Robert Bosch Gmbh | Display with liquid crystal cells |
US4798448A (en) * | 1988-02-16 | 1989-01-17 | General Electric Company | High efficiency illumination system for display devices |
EP0377309A2 (en) * | 1989-01-03 | 1990-07-11 | Minnesota Mining And Manufacturing Company | Back-lit display |
GB2227871A (en) * | 1989-01-03 | 1990-08-08 | Hung Sheng Wen | Character and numeral displaying device |
US5123077A (en) * | 1989-03-20 | 1992-06-16 | Hitachi, Ltd. | Light source device |
-
1992
- 1992-08-18 FI FI923695A patent/FI91810C/en active
-
1993
- 1993-08-12 GB GB9316785A patent/GB2269928A/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1988004789A1 (en) * | 1986-12-20 | 1988-06-30 | Robert Bosch Gmbh | Display with liquid crystal cells |
US4798448A (en) * | 1988-02-16 | 1989-01-17 | General Electric Company | High efficiency illumination system for display devices |
EP0377309A2 (en) * | 1989-01-03 | 1990-07-11 | Minnesota Mining And Manufacturing Company | Back-lit display |
GB2227871A (en) * | 1989-01-03 | 1990-08-08 | Hung Sheng Wen | Character and numeral displaying device |
US5123077A (en) * | 1989-03-20 | 1992-06-16 | Hitachi, Ltd. | Light source device |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1299154C (en) * | 2002-12-20 | 2007-02-07 | 西铁城电子股份有限公司 | Light conducting board and supporter for it |
Also Published As
Publication number | Publication date |
---|---|
FI923695A0 (en) | 1992-08-18 |
FI91810C (en) | 1994-08-10 |
GB9316785D0 (en) | 1993-09-29 |
FI91810B (en) | 1994-04-29 |
FI923695A (en) | 1994-02-19 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |