FI91810C - The light-guide - Google Patents

Description

91810

LIGHT CONTROLLER - LJUSSTYRENHET

The invention relates to a device for controlling the light of a liquid crystal display, i.e. a light controller.

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In liquid crystal displays, light-producing organs, the so-called LEDs (light emitting diodes) are usually placed at or near the edges of the screen. Above these LEDs and above the entire display, a so-called a light guide, which is usually a member of one or more parallel white plates. The purpose of the light guide is to distribute the light generated by the LEDs evenly over the entire display area. A body transmitting information is placed on top of the light guide and a protective glass or the like is placed on top of it.

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It is necessary to direct the light generated by the LEDs to the center of the display, otherwise the light will "escape" to the sides and the display itself will remain almost unlit. Such an inhibition of light escape has hitherto been treated in such a way that the parts of the light guide surrounding the LEDs are coated, for example painted, with a suitable substance. Such a coating of LEDs has acted as a barrier to light escape, but the disadvantage has also been the light-absorbing property of the coating, as a result of which the intensity of the light on the display has decreased.

The object of the present invention is to eliminate said drawback and to provide a light guide which, in addition to effectively preventing light from escaping, also reflects light into the display area.

The features of the invention appear from the claims. The invention thus relates to a device for controlling the light of a liquid crystal display, i.e. a light guide which is placed on the light guide 35 over the light generating means, i.e. the so-called

LEDs, above and to the sides. It is characteristic that the light guide is made of a material whose light source is reflective of the light source and that the light guide is a separate piece from the light guide.

Thanks to the light guide according to the invention, the light can be precisely directed to a defined area, whereby the quality 5 of the display is improved and its power requirement is reduced. Suitable materials for the light guide are either reflective materials per se, such as metals, or non-reflective materials per se, such as various plastics whose surface on the light source side is coated with a reflective coating. The Ky-10 wall material can be rigid or flexible. If the material is flexible, it can be attached, for example, to a tape.

According to a preferred embodiment, the light guide is made of a solid material, and if the LEDs are grouped at different edges in the liquid crystal display and form separate areas and are thus protected by separate light guides, such light guides are interconnected from a solid material. with spacers made in one piece. Preferably, such light guides and their spacer bars are initially formed into a single piece. When this piece is attached to the bottom of the display, which usually corresponds to a circuit board, a stable light display that does not vibrate is obtained.

The structure of the light guide according to the invention is shown in more detail in the following figures.

Figure 1 shows a top view of a light guide.

Figure 2 shows the light guide in a perspective view.

Figure 3 shows the light guide seen from above and protected by two light guides.

Figure 4 is a perspective view of one light guide.

Figure 5 is a plan view of a unitary body comprising two light guides connected by a spacer bar.

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Fig. 6 shows a side view of the intermediate rod according to Fig. 5.

Fig. 7 shows a side view of the light guide according to Fig. 5.

5 In Fig. 1, which shows the light guide 10, the recessed locations of the LEDs are indicated by the reference number 12. At the points 13, the plate 11 is fixed to the bottom of the display.

Figure 3 shows a light guide plate 11 protected by two separate light guides 20. Figure 4 shows in more detail a light guide 10 in which the surface 21 is a curved protective surface of the LEDs 12, and 22 is a flat member to be attached to the plate 11. Of course, the LEDs 12 are not visible through the surface 21 in the devices of Figures 3 and 4, but are marked in the figures only to clarify the structure of the light guide.

Fig. 5 is a plan view of a preferred embodiment of the invention in which the two light guides 20 are connected in one piece by means of a spacer bar 23. Kappa-le can be attached at 24 points to the bottom of the display, for example by soldering. This piece is preferably made of a single-piece, reflective sheet metal plate. Structures made of sheet metal are inexpensive to manufacture and can be easily installed in place.

It will be apparent to those skilled in the art that various embodiments of the invention may vary within the scope of the claims set forth below.

Claims (7)

An apparatus for controlling the light of a liquid crystal display, i.e. a light control unit placed on a photoconductor above and next to light-emitting photodiodes, and said light control unit (20) is made of a material in which the surface facing the light source is light reflective, characterized in that the light control unit is a separate piece with respect to the photoconductor (10). ). Light control unit according to claim 1, characterized in that the light-reflecting surface facing the light source is made of a rigid material. Light controller according to claim 1 or 2, characterized in that the material in the light-reflecting surface facing the light source is a reflective metal. Light control unit according to claim 1, 2 or 3, characterized in that the material in the light-reflecting surface which is resistant to the light source is a metal lined with a reflective coating, hard plastic or the like. Light controller according to any one of claims 1-4, characterized in that it is connected to other light controllers (20) in the same liquid crystal display by means of intermediate bars (23) of rigid material, whereby the separate 1 light controllers together with intermediate bars form a uniform a piece which can be obtained at the bottom of the liquid crystal screen. 6. A uniform piece for stiffening the light at a liquid crystal display, characterized in that it consists of light controllers (20) according to any one of claims 1-4 and interconnecting bars (23) of the controllers, which in number can be a or more, and that the piece is obtainable at the bottom of the liquid crystal display. 7. A piece according to claim 6, characterized in that it was processed as a unitary piece from the beginning.