I was shopping for new display the other day when I stumbled onto a display from BenQ that featured special Low Blue Light technology designed specifically to target the problem of blue light exposure, which can cause eye damage and sleeplessness. The monitor comes with four preset Low Blue Light modes (30% reduction, Web-surfing – 50% reduction, Office – 60% reduction, and Reading – 70% reduction.) Considering that I and others work very long hours in front of a display each day, this kind of feature could be appealing. Earlier this morning I discovered a newly published patent application from Apple in Europe dated today that covers this basic theme of reducing bright backlight reflections using a special blue filter. Without recently bumping into the BenQ information, I wouldn't have understood the potential benefit of using such a special blue filter in a display.

Apple's Patent Background

Electronic devices such as computers and handheld electronic devices have displays such as liquid crystal displays. A liquid crystal display typically has a rectangular central active area surrounded by a ring-shaped inactive area. An array of display pixels in the active area is used in displaying images for a user. A color filter layer formed from an array of color filter elements such as red, blue, and green pigments is used to provide the display with the ability to display color images. The color filter layer includes a black mask in the inactive area.

The black mask is formed from a polymer black masking layer and is used to hide internal display components from view. Portions of the black masking layer are used to create a grid-shaped black matrix in the active area of the display. The black matrix has rectangular openings that are covered by the color filter elements.

In some color filter layer arrangements, the black matrix is formed on the surface of a color filter substrate before the color filter elements are deposited. This can give rise to undesirably large amounts of reflected light from the black matrix during use of the display.

By forming the black matrix after patterning the color filter elements on a color filter substrate, reduced amounts of black matrix are formed in spaces between adjacent color filter elements, thereby reducing black matrix reflections. If care isn't taken, however, black matrix reflections may still be larger than desired.

It would therefore be desirable be able to reduce black matrix reflections in the color filter layer of a display.

Apple's Invention

Apple's invention generally relates to displays, and more particularly, to displays with color filter layers.

A liquid crystal display may be provided with a color filter layer and a thin-film transistor layer. The color filter layer may have a glass substrate covered with color filter element structures. The thin-film transistor layer may have a glass substrate covered with thin-film transistor circuitry. A layer of liquid crystal material may be interposed between the color filter layer and the thin-film transistor layer. Upper and lower polarizer layers may be formed above and below the color filter layer and the thin-film transistor layer.

The display may have an active area with an array of display pixels. An inactive area may surround the active area. A black mask structure may be formed in the inactive area. A black matrix having a grid shape with rectangular openings may be formed in the active area. Red, green, and blue color filter elements may overlap the rectangular openings of the black matrix.

The black matrix may have a first layer that is formed from a grid of blue photoresist that is deposited and patterned directly on an inner surface of the color filter substrate and may have a second layer that is formed from an aligned grid of black photoresist. Edge portions of the color filter elements may be interposed between the blue grid of photoresist and the black grid of photoresist.

In the inactive area, the black mask structure may be formed from a blue layer of photoresist covered with a black layer of photoresist. Further features, their nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.

Apple's patent FIG. 3 is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention.





Although Apple talks about reducing undesirable large amounts of reflected light from the black matrix during use of the display, they never provide insight to specific benefits to the user. Instead the invention remains relatively technical throughout. The reason for this may be that Apple could have recently acquired this patent being that the one and only inventor is from Korea where some of the biggest advances in displays are made. Korean companies like Samsung are great with the technical aspects of a patent application but rarely spend much time on describing end-user benefits.

Considering that this is a patent application, the timing of such a product to market is unknown at this time. Whether the benefits could match those presented by BenQ are equally unknown at this time.







Apple's patent application was published in Europe today, December 24, 2014. It was originally filed on June 17, 2013. The patent notes that the inventor was from Korea. The application also oddly acknowledged Apple's patent agent Louis Levenson from San Francisco.



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