Light guide plate having a reversed micro-pattern in its mixing zone

Inactive Publication Date: 2013-12-12
SKC HAAS DISPLAY FILMS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is a light guide plate with reduced hot spots. The plate has a structure that redirects the light from discrete light sources toward the Y-axis (perpendicular to the input surface) by using a set of lenses and micro-lenses. The density of the micro-lenses varies in the X-axis, with a maximum value at a location that matches the center of one of the discrete light sources and a minimum value at a location that matches the center of two adjacent discrete light sources. This design ensures uniform distribution of light from the discrete light sources and reduces hot spots on the output surface.

Problems solved by technology

Subsequently, the pitch of the LEDs has become larger, which results in a more noticeable hot spot problem, that is, more light is distributed near each LED than between LEDs in the first few millimeters of the viewing area of the LCD.
The hot spot problem occurs because light from the discrete LEDs enters the LGP non-uniformly, that is, more light is distributed near the LEDs than between the LEDs.
While the prior art LGPs are capable of suppressing the hot spot problem to a certain degree, they are still not satisfactory due to the complexity in the mass production of those LGPs.

Method used

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  • Light guide plate having a reversed micro-pattern in its mixing zone
  • Light guide plate having a reversed micro-pattern in its mixing zone
  • Light guide plate having a reversed micro-pattern in its mixing zone

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Embodiment Construction

[0020]FIG. 1A shows schematically a side view of an LCD display apparatus 30 comprising an LCD panel 25 and a backlight unit 28. Backlight unit 28 comprises a plurality of optical components including one or two prismatic films 20, 20a, one or two diffusive films 24, 24a, a bottom reflective film 22, a top reflective component 26, and a light guide plate (LGP) 10. LGP 10 is different from the other optical components in that it receives the light emitted from one or more light sources 12 through its input surface 18, redirects the light emitted through its bottom surface 17, end surface 14, output surface 16, side surfaces 15a, 15b (not shown) and reflective film 22, and eventually provides light relatively uniform to the other optical components. Output surface 16 has a plurality of elongated grooves 36. Target luminance uniformity is achieved by controlling the density, size, and / or orientation of the lenses 100 (sometimes referred to as discrete elements, or light extractors) on ...

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Abstract

The present invention provides a light guide plate having reduced hot spots comprising an input surface for receiving light from a plurality of discrete light sources, an output surface for emitting light, a bottom surface opposing to the output surface, and an end surface opposing to the input surface.

Description

FIELD OF THE INVENTION[0001]This invention generally relates to a light guide plate, and more particularly, to a light guide plate having a reversed one- or two-dimensional micro-pattern in its mixing zone to reduce undesirable hot spot defects caused by discrete light sources.BACKGROUND OF THE INVENTION[0002]Liquid crystal displays (LCDs) continue to improve in cost and performance, becoming a preferred display type for many computer, instrumentation, and entertainment applications. Typical LCD-based mobile phones, notebooks, and monitors include a light guide plate (LGP) for receiving light from a light source and redistributing the light uniformly across the light output surface of the LGP. The light source, conventionally being a long, linear cold-cathode fluorescent lamp, has evolved to a plurality of discrete light sources such as light emitting diodes (LEDs). For a given size LCD, the number of LEDs has been steadily decreasing to reduce cost. Subsequently, the pitch of the L...

Claims

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Application Information

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IPC IPC(8): F21V8/00
CPCG02B6/0011G02B6/0036G02B6/0038G02B6/0043G02B6/0068G02B5/02G02B5/04G02B6/12G02F1/1335
InventorMI, XIANG-DONG
OwnerSKC HAAS DISPLAY FILMS CO LTD