Twisted nematic effect was a breakthrough LCD technology that became dominant during the 1980s and 1990s. However, TN panels suffered from several limitations and the disadvantages of TN display technology restricted the applications of LCD.
Nonetheless, the introduction of in-plane switching or IPS during the mid 1990s and its mass popularity in mid 2000s marked another breakthrough in LCD technology. IPS display technology has expanded the application of LCD to include high-definition television and computer monitors, as well as high-resolution mobile devices such as smartphones and tablets.
This article lists down and describes the advantages and disadvantages of in-plane switching display technology, thus also discussing the strengths and limitations or drawbacks of IPS LCD panels.
The benefits: Advantages of IPS LCD panels
1. Better color reproduction: One of the notable advantages of IPS LCD panels over TN panels is color reproduction that further translates into color accuracy and better image quality.
Note that a typical TN panel only has a 6-bit RGB color depth. This means that it is only capable of producing 262,144 possible colors. On the other hand, a conventional IPS has an 8-bit RGB color depth capable of producing 16.7 million possible colors.
Though another type of LCD technology called virtual alignment or VA has a similar 8-bit RGB color depth, several manufacturers have introduce high-end IPS panels with 16-bit to 24-bit RGB color depth.
Active-matrix organic light-emitting diode or AMOLED display technology is a close competitor of IPS display technology. Between the two however, IPS has better color accuracy because AMOLED panels are prone to producing images with strong or highly saturated colors.
When compared against TN panels and VA panels, as well as AMOLED panels thereby, IPS LCD panels produce more vibrant images and more realistic colors. This advantage means that in-plane switching is an ideal display option for use in multimedia consumption, as well as in color critical work such as photo editing, graphic design, and video editing.
2. Wide viewing angle: TN panels also suffer from very limited viewing angle as demonstrated by poor off-axis image quality. The introduction of VA LCD technology tried to resolve this limitation. But VA panels suffer from color shifts when viewed from a slightly different angle.
Nonetheless, wide viewing angle is another advantage of in-plane switching over TN and VA display technologies. Typical IPS LCD panels will produce no image distortion and relatively minimal color shifts when viewed from different angles while high-end IPS panels will display consistent contrast and brightness levels under different viewing angles.
This advantage of IPS panels is made possible because the technology involves the capacity to change the physical behavior of the liquid crystal layer by making the crystal molecules respond to the electric field in parallel to the TFT. This also results in better color reproduction.
For smartphone and tablet applications, the aforementioned advantage means that these portable devices can be held in various angles and eye levels. This advantage also means that television sets or computer monitors with IPS panels offer a better visual experience than other LCD panels.
3. Better sunlight visibility: Colors and images on an IPS panel remain considerably more visible under bright outdoor lights or direct sunlight than other display technologies. This is an advantage of in-plane switching technology over TN and AMOLED display technologies.
The better color reproduction coupled with better viewing angle and backlighting make IPS usable or viewable under direct sunlight. Note that TN panels suffer from poor visibility under direct sunlight because of its limited color depth. AMOLED panels, on the other hand, have similar problems because of the inapplicability of backlighting.
4. Longer lifespan: Dead pixels are an inherent issue affecting different LCD technologies. The lifespan of IPS LCD panels cannot be generally compared against the lifespan of TN panels or VA panels.
However, it is important to note that TN display technology is easier to implement and thus, TN panels are easier to produce. This further translates to more manufacturers producing TN panels, this increasing the tendency for low manufacturing standards. Some manufacturers are also producing low-end TN panels to meet demands for cheaper LCD.
When generally compared against typical TN panels nonetheless, IPS panels might have a longer lifespan. On the other hand, the lifespan of VA panels might be comparable with IPS. Remember that this is an overstatement.
Compared against AMOLED panels however, IPS panels have obvious longer lifespan. Remember that one of the notable limitations of AMOLED is its susceptibility to noticeable pixel degradation and faster screen burn-ins.
The drawbacks: Disadvantages of IPS LCD panels
1. Contrast ratio: When compared against TN panels, IPS LCD panels have better contrast ration because it has better color depth. However, VA panels and AMOLED panels have better contrast ratio than IPS panels.
Backlighting can be blocked effectively in a vertical alignment display technology. This produces deeper blacks and subsequently, higher contrast ratio compared to in-plane switching display technology.
On the other hand, AMOLED panels naturally produce deep blacks because they represent the absence of light and thus, the absence of color. This results in higher contrast ratio. Although IPS technology produces intense whites, high-end AMOLED panels can also rival typical IPS panels in this regard.
2. Power consumption: Another disadvantage of IPS panels when compared against TN panels and AMOLED panels is power consumption. In-plane switching technology consumers more power than TN or AMOLED display technologies.
Note that TN panels are suitable for battery-operated and low-powered devices. On the other hand, a typical IPS panel requires 15 percent more power than a TN panel. IPS panels also require a strong backlighting to improve display clarity unlike AMOLED panels.
This drawback means that consumer electronic devices featuring an IPS panel have more power requirements than counterpart devices equipped with TN or AMOLED panels. This affects the overall energy efficiency rating and battery life performance of a specific device.
3. Pixel response time: Other disadvantages of in-plane switching technology are slow pixel response time and low refresh rate. The response time and refresh rate of IPS panels are slower and lower than TN or AMOLED panels.
Pixel response time is the duration it takes a single pixel to transition from one state to another. Refresh rate is the frequency in which the image in a display is refreshed. Slow pixel response time and low refresh rate create ghosting effects and motion blurs around a moving image. In addition, both ghosting effects and motion blurs are more straining to the eyes.
This limitation makes an IPS panel an unsuitable display option for use in fast-paced and competitive gaming. TN display technology has the faster response time and higher refresh rates among existing LCD technologies. This is the reason why some hardcore gamers still prefer TN panels to IPS or VA panels despite having poor color reproduction.
Manufacturers have produced IPS panels with better response times and refresh rates. However, these panels are more expansive than TN panels, thus making them unappealing to budget-conscious consumers.
4. Cost and price: Manufacturing IPS LCD panels is costlier than manufacturing TN panels because of the involved engineering complexity. This higher manufacturing costs results in higher prices for end consumers.
Entry-level laptops such as netbooks, as well as feature phones and budget smartphones are commonly equipped with TN panels. Devices with IPS LCD panels are relatively more expensive. Note that high-grade IPS panels are featured in top-of-the-line products with higher price tags.
Between in-plane switching and AMOLED display technologies however, both are also costly to manufacture and both IPS and AMOLED panels are commonly featured in premium products such as high-end smartphones and tablet computers.
Conclusion: Advantages and disadvantages of IPS panels
From the aforementioned, in-planed switching display technology outperforms other LCD technologies such as twisted nematic and vertical alignment. The strengths or advantages of IPS LCD panels center on better image production and visual performance stemming from having higher color depth, more accurate color reproduction wider viewing angle, and better visibility under direct sunlight.
Nonetheless, the drawbacks and disadvantages of IPS LCD panels make them unappealing to some extent. They are not as power efficient as TN or AMOLED panels. They are not as inexpensive or as readily accessible as TN panels as well. These disadvantages translate to the limited applications of in-plane switching technology when cost or price and power consumption are factored in.
Further readings: (1) Kim, K. H. & Song, J. K. 2009. Technical Evolution of Liquid Crystal Displays. NPG Asia Materials. 1, pp. 29-36. DOI: 10.1038/asiamat.2009.3; (2) Kim, J. J., Park, E., & Sundar, S. S. 2012. IPS vs. AMOLED: Effects of Panel Type on Smartphone Users’ Viewing and Reading Experience. In eds. Park, J., Jin, Q., Sang-soo, Y. M., & Hu, B., Human Centric Technology and Service in Smart Space. DOI: 10.1007/978-94-007-5086-9_11; and (3) Aoki, N., Komura, S., Furuhashi, T., Adachi, M., Itou, O., Miyazawa, T., & Ohkura, M. 2007. Advanced IPS Technology for Mobile Applications. Journal of the Society for Information Display. 15(1), pp. 23-29. DOI: 10.1889/1.2451548.