Manufacturing Display Panels – Quality Consistency

Consistency remains a challenge for Display Panel Manufacturers

There are plenty of variations in manufacturing display panels on a large scale, which result in color and intensity inconsistency in panel products, especially from batch to batch.

MD100N Spectroradiometer (desktop)

▸MK550T Spectroradiometer

▸MD100N Spectroradiometer

▸Light Calibration Solution

The challenge of maintaining consistency in display panels

There are many variables in the mass production of OLED/LED Display Panels, which manifests as color and intensity inconsistency between products.

According to BenQ, If you compare two panels of same make and model, side by side, there is a 95% chance you will find variations in color and intensity.

(Why don’t colors look the same across different devices? – BenQ.com)

This same problem exists in mobile phone display panels.  

(Why do all iPhone x screens look different? – An Zhenji at Huangjianet.com)

The challenges that panel manufacturers face

A display panel manufacturer can easily calibrate a single display panel with their own specialized equipment and precision measuring instrumentation.  However, to perform this on several production lines for every single panel is not practical.  Replicating this specialized equipment is expensive and notoriously slow.

Another option is using a 3-Color RGB colorimeter for evaluating display panel performance, but this has been shown to produce inaccurate data because:

  • The reflectance or transmittance rate is not included in the calculation
  • There is no standard observer and perspective
  • 3-Color RGB evaluation of an entire spectrum is not adequate

Spectroradiometer solution

Manufacturers are turning to specialized spectroradiometers for panel evaluation and calibration to alleviate the niggling problem of consistency on production lines.  Why a spectroradiometer?

A spectroradiometer can yield very precise measurments, by separating the spectrum into finer color details.  In the case of the UPRtek MK550T, a diffraction grating is used at 1nm intervals that can yield up to 400 different color wavelengths.   A single measurement can be up to 10x faster than other laboratory/research level equipment.

Spectroradiometers with diffraction grating vs. Colorimeters with RGB Filters

RGB Colorimeters are inaccurate in determining chroma values

Spectroradiometers on a production line

Most display manufacturers have their own QC hardware/software support built into their own products and production lines.  UPRtek spectroradiometers are integrated into this process for accurate and fast measurements.

Integration is done through UPRtek device SDK (Systems Developer Kit) interface that allows manufacturers to exchange measurement data to assist their RD efforts.

UPRtek spectroradiometers are also supported by the popular Calman Studio software used to help evaluate and calibrate panel performance. This setup is mostly used in RD environments, using spectroradiometers for repeated, baseline testing, performed efficiently and accurately.

Why specialized spectroradiometers are important?

There are usually several production lines in a factory plant, which means that you will need more than one spectroradiometer.  All of these spectroradiometers must also be identical in measurement precision. 

This is where specialization is important and where UPRtek products standout in the industry.  UPRtek spectroradiometers follow strict guidelines from important standards organizations; NIST, JIS and VESA.  Additionally, all of our products are required to be recalibrated on a regular basis.

MK550T Spectroradiometer

 Viable solutions for manufacturing Display Panels looking for repeatable consistency.

There are plenty of variables in manufacturing Display Panels on a large scale, resulting in inconsistency in products.  Manufacturers incorporate R&D efforts to alleviate these problems, which can be expensive and time consuming as a QC solution for production lines.

These companies are turning to specialized spectroradiometers by UPRtek, as a cost-saving, efficient and accurate solution.

Resources:

Why don’t colors look the same across different devices (BenQ)
https://www.benq.com/en-us/knowledge-center/knowledge/why-dont-colors-look-the-same-across-different-devices.html

Why do all iPhone x screens look different? – Huangjianet.com
https://www.hangjianet.com/topic/15459612704410000

Handbook Series

The Flicker Handbook

A comprehensive look at Flicker, why we have it, what problems it presents, how you can measure it and what you can do to avoid it.

▸ Get it!

About UPRtek

United Power Research and Technology

UPRtek (est. 2010) is a manufacturer of portable, high-precision light measurement instruments; Handheld Spectrometers, PAR meters, Spectroradiometers, Light Calibration Solutions.

UPRtek HQ, R&D and manufacturing are all based out of Taiwan, with Worldwide representation through our certified Global Resellers.

▸ Read on

Announcements

UPRTEK AT THE 30TH INTERNATIONAL CONFERENCE ON ARABIDOPSIS RESEARCH (ICAR 2019)

UPRtek's partner in China, Quelighting Optoelectronics Co., Ltd, and Plant Growth Chamber Manufacturer Ningbo Jiangnan Instrument Factory will attend the 30th International Conference on Arabidopsis Research (ICAR ) which is being held on June 16-21 at Huazhong Agricultural University in Wuhan City, Hubei Province, China.

▸ Read on.