Organic EL Display Spacer Placement for Brightness
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Solution Overview
Problem
As display devices improve in resolution, the reduced size of pixels makes it difficult to dispose spacers without reducing the light emitting area, leading to decreased brightness and shortened device lifetime when trying to compensate with increased electric current.
Innovation Solution
The spacer is strategically placed in the blue light emitting area of the organic EL display device, which has less effect on visibility, allowing for its presence in high-definition displays without deteriorating display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spacers are disposed in non-light emitting areas, then foreign substance damage is prevented, but pixel size must be large enough to accommodate spacers
Solution Approach 1:
The patent transitions from disposing spacers in the planar dimension (non-light emitting areas) to disposing spacers in the vertical dimension (on top of the organic EL element). This allows the vapor deposition mask to be positioned at a higher level, maintaining the protective spacing function while preserving the full pixel area for light emission.
2Reliability
If spacers are disposed in light emitting areas to protect from foreign substances, then protection is provided, but the light emitting area size is reduced
Solution Approach 1:
The patent moves the spacer disposition from the horizontal plane (occupying light emitting area) to the vertical dimension (on top of the element). This elevates the protective function to a different spatial dimension, allowing the light emitting area to maintain its full size while still providing foreign substance protection through the vertical spacing created by the spacer.
3Reliability
If light emitting area size is reduced due to spacers, then protection is provided, but brightness is reduced
Solution Approach 1:
By disposing spacers vertically on top of the organic EL element rather than horizontally within the light emitting area, the patent eliminates the trade-off between protection and brightness. The vertical spacer configuration provides foreign substance protection without occupying any light emitting area, thereby maintaining full brightness output.
4Illumination intensity
If electric current is increased to compensate for reduced brightness, then brightness is maintained, but device lifetime is shortened
Solution Approach 1:
The vertical spacer configuration eliminates the need to increase electric current to maintain brightness, because the light emitting area is not reduced. By providing protection in the vertical dimension rather than consuming horizontal light emitting area, the patent maintains normal brightness levels with normal current, thereby preserving device lifetime.
Data Source
AI summary
An organic EL display device includes a plurality of pixels including first pixels and second pixels. Each of the plurality of pixels includes a red sub-pixel including a red light emitting area emitting red light, a green sub-pixel including a green light emitting area emitting green light, and a blue sub-pixel including a blue light emitting area emitting blue light. The blue sub-pixel included in the first pixel is provided with a spacer at a portion of an area corresponding to the blue light emitting area included in the second pixel.