Obviousness

Obviousness Analysis of US Patent 10,832,616 under 35 U.S.C. § 103

This analysis identifies combinations of prior art references that would render independent claims 1 and 13 of US Patent 10,832,616 (hereinafter "US'616") obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention.

Understanding the PHOSITA

A person having ordinary skill in the art in the field of organic light-emitting diode (OLED) displays would typically possess a bachelor's degree in electrical engineering, materials science, physics, or a closely related discipline, along with several years of practical experience in the design, manufacturing, or processing of display devices. Such a PHOSITA would be familiar with various pixel arrangements, display manufacturing techniques (especially fine metal mask (FMM) deposition for OLEDs), and common challenges such as optimizing aperture ratio, ensuring deposition reliability, and managing the lifespan of different colored pixels.

Obviousness of Independent Claim 1

Claim 1 of US'616 recites:
A pixel arrangement structure of an organic light emitting diode (OLED) display, comprising:
a plurality of individually addressable pixels for displaying images, the individually addressable pixels being minimum addressable units of the OLED display and comprising:
a first pixel having a center coinciding with a center of a virtual square;
another first pixel having a center coinciding with a center of another virtual square, the virtual squares sharing a common side having endpoints at a common first vertex and a common second vertex of the virtual squares, with neighboring vertices in each of the virtual squares corresponding to pixels configured to emit different color light;
a second pixel separated from the first pixels and having a center at the first vertex;
an other first pixel on a line defined by the center of the virtual square and the first vertex, the first pixel, the second pixel, and the other first pixel being consecutive pixels on the line; and
a third pixel separated from the first pixels and the second pixel, and having a center at the second vertex,
wherein a shortest distance between the first pixel and the second pixel as well as a shortest distance between the first pixel and the third pixel is a same first length,
wherein a shortest distance between the first pixels is a second length that is longer than the first length and a shortest distance between each of the second pixels and the third pixels,
wherein the second pixel and the third pixel have polygonal shapes, and
wherein the second pixel has a larger area than that of the third pixel.

An obviousness argument can be established by combining the teachings of US20110012820A1 to Kim (hereinafter "Kim"), JP2010153173A to Semiconductor Energy Lab Co Ltd (hereinafter "Semiconductor Energy Lab"), and US20080001525A1 to Au Optronics Corporation (hereinafter "Au Optronics").

Primary Reference: US20110012820A1 to Kim

Kim discloses an organic light-emitting display with a pixel unit where a plurality of first sub-pixels (G), second sub-pixels (B), and third sub-pixels (R) are arranged. The arrangement includes first sub-pixels (G) in a first direction, and second (B) and third (R) sub-pixels arranged diagonally, such that two second sub-pixels are separated by one first sub-pixel, and two third sub-pixels are separated by one first sub-pixel. Kim's FIG. 1 explicitly illustrates a first sub-pixel (G) at the center of a virtual square, with second (B) and third (R) sub-pixels at the vertices. The description further clarifies that the first, second, and third sub-pixels have polygonal shapes (e.g., quadrilateral for G, and octagonal for B and R). The repeating "matrix" arrangement of pixels in Kim's disclosure inherently creates "another first pixel" centered in "another virtual square" that shares a common side with the first virtual square, where the endpoints of the common side correspond to pixels configured to emit different colored light (e.g., B and R). Kim also states that the second and third sub-pixels are larger in area than the first sub-pixel.

However, Kim teaches that the distances between adjacent pixels (e.g., first-second, first-third, second-third) and between neighboring same-colored pixels (e.g., first-first) are "substantially equal." This directly contradicts the specific unequal distance relationships claimed in US'616.

Secondary Reference 1: JP2010153173A to Semiconductor Energy Lab

Semiconductor Energy Lab discloses a substrate for film formation and a method for manufacturing a light-emitting device, with the objective of forming organic light-emitting elements with high precision. This reference describes arranging "hole sections" and "opening parts" alternately, where the "hole section is provided with a film formation part and a non-film formation part which are separated from each other at a predetermined interval." This demonstrates a recognition in the art that the precise control and variation of intervals (gaps) are crucial for high-precision film deposition.

Secondary Reference 2: US20080001525A1 to Au Optronics

Au Optronics describes an OLED device comprising red, green, and blue sub-pixels, wherein each blue sub-pixel has a larger area than each green sub-pixel, and each green sub-pixel has a larger area than each red sub-pixel. Crucially, Au Optronics provides a clear motivation: "In the OLED display panels, blue sub-pixels have the shortest life span. To obtain a longer life span of OLED display panel, each blue sub-pixel often needs a larger area." This directly addresses the specific claim feature of the second pixel (typically blue) having a larger area than the third pixel (typically red or green), driven by the known issue of blue pixel degradation.

Motivation to Combine

A PHOSITA would be well aware of the challenges in OLED display manufacturing, particularly the trade-off between maximizing the aperture ratio (which favors smaller gaps between pixels) and ensuring reliable FMM deposition (which can benefit from larger gaps to mitigate mask misalignment or material flow issues). This problem is explicitly articulated in the background section of US'616.

1. Combining Kim with Semiconductor Energy Lab for Unequal Gaps: Given Kim's pixel arrangement, which uses substantially equal gaps, a PHOSITA would recognize potential FMM deposition reliability issues, as identified in the background of US'616. Motivated to address these known reliability concerns, the PHOSITA would look to known techniques for improving deposition precision. Semiconductor Energy Lab teaches the importance of using "predetermined intervals" for high-precision film formation. Applying this principle, the PHOSITA would be motivated to selectively adjust the gaps in Kim's arrangement. It would be an obvious design choice to make the "shortest distance between the first pixels" (i.e., between two green pixels in a repeating pattern, which typically form a more extended grid) longer than other adjacent pixel gaps. This specific adjustment would predictably improve deposition reliability for the first pixels during FMM processing, a desirable outcome for mass production.

2. Combining Au Optronics with Kim for Pixel Area Differences: Kim discloses that second and third pixels are larger than first pixels, but not the specific relative areas of second and third pixels. However, the shorter lifespan of blue OLED emitters compared to red and green is a well-known technical problem in the field. Au Optronics provides a direct and explicit solution: making blue sub-pixels larger in area to compensate for their shorter lifespan and extend the overall display's operational life. A PHOSITA, familiar with Kim's pixel arrangement and the general understanding of OLED characteristics, would be motivated to incorporate this known solution from Au Optronics into Kim's structure. If the second pixel in Kim's arrangement is designated as blue (as is common and suggested in US'616's exemplary embodiments), then making the second pixel's area larger than the third pixel's area would be a straightforward application of a known technique to solve a known problem (blue pixel degradation).

Therefore, the combination of Kim's pixel arrangement with the gap-optimization principles for deposition precision from Semiconductor Energy Lab and the lifespan-compensating area adjustments from Au Optronics would render Claim 1 obvious to a PHOSITA.

Obviousness of Independent Claim 13

Claim 13 of US'616 recites:
A pixel arrangement structure of an organic light emitting diode (OLED) display, comprising:
a plurality of individually addressable pixels for displaying images, the individually addressable pixels being minimum addressable units of the OLED display and comprising:
a first pixel having a center coinciding with a center of a virtual square;
another first pixel having a center coinciding with a center of another virtual square, the virtual squares sharing a common side having endpoints at a common first vertex and a common second vertex of the virtual squares, with neighboring vertices in each of the virtual squares corresponding to pixels configured to emit different color light;
a second pixel separated from the first pixels and having a center at the first vertex; and
a third pixel separated from the first pixels and the second pixel, and having a center at the second vertex,
the first pixel, the second pixel, and the third pixel have polygonal shapes,
a shortest distance between the first pixel and the second pixel as well as a shortest distance between the first pixel and the third pixel is a same first length, and
a shortest distance between the first pixels is a second length that is longer than the first length and a shortest distance between each of the second pixels and the third pixels.

Claim 13 is similar to Claim 1 but does not include the limitation regarding the second pixel having a larger area than the third pixel. Thus, an obviousness argument for Claim 13 can be established by combining the teachings of US20110012820A1 to Kim and JP2010153173A to Semiconductor Energy Lab Co Ltd.

Primary Reference: US20110012820A1 to Kim

As described for Claim 1, Kim discloses all the elements of the pixel arrangement structure, including:

• A first pixel at the center of a virtual square, with second and third pixels at the vertices, separated by the first pixel.
• A repeating matrix arrangement implying "another first pixel" in "another virtual square" sharing a common side, with different colored pixels at the shared vertices.
• All pixels having polygonal shapes.

However, Kim teaches that all inter-pixel distances, including the distances between first-second, first-third, second-third, and neighboring first-first pixels, are "substantially equal." This directly conflicts with the specific unequal distance relationships claimed in US'616.

Secondary Reference: JP2010153173A to Semiconductor Energy Lab

As described for Claim 1, Semiconductor Energy Lab addresses the manufacturing precision of organic light-emitting elements by controlling "predetermined intervals" or gaps in the film formation process. This reference teaches that designing and varying these intervals is a known approach to achieving high-precision deposition.

Motivation to Combine

As previously noted, a PHOSITA would be keenly aware of the inherent conflict between achieving a high aperture ratio (requiring minimal gaps between pixels) and ensuring robust FMM deposition reliability (which can be aided by more generous spacing) in OLED manufacturing. This problem is explicitly detailed in the background of US'616.

Kim provides a relevant pixel arrangement, but its teaching of "substantially equal" gaps would present known manufacturing challenges related to FMM deposition. Faced with these challenges in Kim's arrangement, a PHOSITA would be motivated to improve deposition reliability while maintaining efficient space utilization. Semiconductor Energy Lab provides a general teaching that designing and varying intervals (gaps) is a known method to achieve high-precision film formation. Applying this principle to Kim's pixel structure, the PHOSITA would predictably make certain gaps larger to improve deposition reliability. Specifically, increasing the "shortest distance between the first pixels" (e.g., green pixels, which typically form the backbone of the display matrix) to be longer than other immediate adjacent pixel gaps (first-second and first-third) would be an obvious design modification to facilitate FMM processing and enhance deposition reliability for these repeating elements.

Therefore, the combination of Kim's pixel arrangement with the recognized need for variable gap engineering for manufacturing precision from Semiconductor Energy Lab would render Claim 13 obvious to a PHOSITA.