108
Cinematic Sound OLED Technology
1. Summary of Technology
LG Display was the first in the world to develop and produce Cinematic Sound OLED , which uses large 77/65/55 inch OLED modules to vibrate the panel and play sound. The core idea of Cinematic Sound OLED technology works by vibrating the panel with an exciter attached to the back of the panel. TVs that have this technology produce a higher quality of sounds than regular TVs. By being applied to OLED TVs, which implement perfect imaging and distinguished designs, Cinematic Sound OLED provides a new experience of top-notch sound and visuals with brilliant designs. The industry has recognized its excellence and anticipates further expansion to smartphones, monitors, and automobiles. 
2. Motivation
One day, I was watching a TV drama while relaxing at home. When I turned up the volume as I couldn’t hear the sound, my wife who was washing dishes scolded me for the loud noise. I went to where she was standing, and it was indeed too loud. After checking each factor, I realized that TVs have a critical weakness in terms of the sound system that isn’t easy to overcome.
With the advent of slim TVs with thin bezels and better designs, the speakers that used to be on the sides are now at the bottom or behind the TV. The sound that came out of these speakers headed toward the floor (down firing, Image 1), which bounced back before being delivered to the viewers. This lowered the intelligibility of the sound. To improve this, speakers were placed on the side through technological development. However, they looked unpleasant in terms of the design. It was thus difficult to come up with a technology that satisfied both the sound quality and design. The basis of a technology that could overcome both problems was established when LG released the world’s first OLED TV. Next, I will explain the structure, mechanism, and features of Cinematic Sound OLED technology.
3. Features and Distinction
Image 2 shows an OLED module structure with Cinematic Sound OLED technology. The speakers that we commonly find play sounds by vibrating off the oscillator made of paper, but Cinematic Sound OLED utilizes the entire panel as the oscillator. In other words, OLED TV plays sound off its display panel without a separate set of speakers. The mechanism is as follows. Image 3 shows the exciter applied to the OLED module. Exciters attached to the back of the panel transfer the electronic sound signals into physical vibrations, delivering them to the entire panel to play sounds.
These exciters that vibrate consist of a magnetometer, an electrometer, and a vibrometer. The magnetometer and electrometer transfer sound signals into vertical vibrations through a permanent magnet and a solenoid coil. The vibrometer then transmits the vibrations to the panel. It’s important to prevent the vertical vibration from turning horizontal and to mitigate the distortion of the vibration using a damper. LG has also developed an enclosure system to control the sound box and reflected waves for improving the sound quality of Cinematic Sound OLED. The enclosure changes the acoustic features depending on the shape and material of its tape. It is designed through surface analysis of vibrations and acoustic features. Also, another task is to control the heat generated from this vibration.
OLED TV produces the optimal quality of images through vivid colors, an infinite range of contrast, and wide viewing angles. The mechanical structure is quite simple. There’s one sheet of glass panel less than 1mm thin and another sheet of flat metal plate. This enables the cutting-edge design of ultra-slim Wallpaper TV. Cinematic Sound OLED technology combines OLED TV with plate speaker technology. Important advancements are being made in LCD TVs, but its multilayered structure that includes a backlight hinders the exciter’s delivery of vibration to the front of the panel. The shaking of liquid crystals also blurs the screen. Compared to this, OLED TV has a simple structure. Due to its self-illuminating feature, the screen doesn’t have the blurring problem either.
Cinematic Sound OLED also produces excellent sound quality. Image 4 shows the aspects of this technology’s sound quality. First, Cinematic Sound OLED has excellent acoustic features. In general, TVs place the speaker in the back and send the sound downward, which causes unbalanced acoustic features and is affected largely by the surrounding environment. However, with Cinematic Sound OLED, the vibration from the exciter is delivered directly to the viewer through the OLED panel, which creates clear and balanced sounds from low to high pitches. Second, Cinematic Sound OLED creates a wide range of sound field. Since the OLED panel functions as the oscillator of a large speaker, the sound field fills the entire screen, amplifying the realness of sound. Third, the technology matches the localization of image and sound. In most other TVs, the image and sound are played from different locations, creating an unnatural imbalance of playback. But this technology enables the accordance in localization of image and sound. In other words, the location of the talking person’s face and its sound origin are matched completely. It sounds natural and maximizes the sense of realness, amplifying the immersive experience of viewers. Because the screen and the speaker are separated in ordinary TVs, it was hard to match the sound image and the location. Using audio settings such as Bluetooth speaker systems for higher sound quality worsens such discord.
Image 5 demonstrates the result of sensitivity tests on viewers’ brainwaves and sound quality. While brainwaves of viewers who watched ordinary TVs showed δ and θ waves, which are similar to the states of rest or sleep, and those of OLED TV viewers were dominantly β waves, showing the state of concentration. In other words, Cinematic Sound OLED technology amplifies the immersive experience of viewers in image and sound. Image 6 indicates the sound test results of Sony A1 OLED TV from Rtings, an expert media outlet on TV quality ratings. According to the test results, the sound quality of LG’s Cinematic Sound OLED received the top mark out of 79 products.
Cinematic Sound OLED has been critically acclaimed since its introduction at CES 2017, the largest electronics exposition in the world. It was an entirely unexpected technology that pioneered the new territory beyond the category of display, which expanded the innovation of TV to design and auditory fields. It’s also a technology that converges video and audio, with infinite potentials to expand in numerous products and businesses.
4. Applications
In 2017, Sony released Bravia A1 OLED TV that applies this module. They introduced LG’s Cinematic Sound OLED technology as “Acoustic Surface”. Since the launch, there has been much interest in LG’s Cinematic Sound OLED technology. We are currently undertaking cooperative developments with our partners to release new products.
5. Expectations
Cinematic Sound OLED technology is a successful and exemplary case of technological convergence that combines display with sound. Such convergence of technologies offered the direction of development in the future. They will hasten the realization of futuristic inventions that have only been imagined, changing the lifestyle of humankind.
6. Future Development Tasks
Aside from large OLED TVs, Cinematic Sound OLED technology can be expanded to a wide variety of fields, such as monitors, laptops and smartphones. For instance, applying this technology on a mobile phone will eliminate the need for the speaker hole at the top of mobile phones, enabling differentiated designs. Through continuous R&D, LG Display will converge our ultra-high resolution technology with technologies from diverse fields to develop them into something entirely new. We will fully prepare our production capacity to respond to the expanding market, in order to lead the future of the display market.
