STEREO-Light™ Technology: Illuminating Every Note and Key with Perfect Balance

BenQ Lighting Lab

Eye-Care Ergonomics Piano Light BenQ Eye-Care Solution Illuminance

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BenQ's innovative STEREO-Light™ lighting control technology addresses the challenge of illuminating two distant and differently angled work areas simultaneously—the music sheet and the piano keys. The technology splits the light into two beams: one dedicated to vertically illuminating the music sheet, and the other to illuminating the horizontal surface of the piano keys. This ensures even lighting for both areas, effectively reducing glare and eye strain while enhancing visual comfort and overall lighting quality.

Visual Challenges of Reading Sheet Music and the Limitations of Traditional Desk Lamps

The font size of sheet music is typically 7-9 points, smaller than the 10-12 point size found in books. Sheet music is densely packed with notes, and while playing, a pianist’s fingers are constantly moving, and the body shifts as well. In this scenario, the eyes must focus closely and intensely on the sheet music, leading to quick fatigue. During playing, the eyes need to repeatedly adjust focus, causing the ciliary muscles to strain, which can accelerate the development of myopia.

Traditional desk lamps with symmetrical light distribution often fail to meet the illumination standards recommended by the Illuminating Engineering Society (IES) for concert halls. These lamps commonly result in uneven lighting, where the top of the sheet music is overly bright while the bottom is dim, and the center of the piano keys is illuminated while the sides remain dark.

STEREO-Light™ lighting control technology uses a combination of reflective aluminum sheets and convex lens technology to focus light evenly across both the sheet music and the piano keys, ensuring all lighting levels meet the recommended concert hall standards. This not only enhances visual comfort but also improves piano practice efficiency.

Challenges of Piano Lighting

Piano lighting differs from other scenarios that only need to illuminate a single work area, as it must simultaneously light two components that are far apart and at different angles: the nearly vertical and rear-positioned sheet music, and the horizontally extended piano keys.

The specific challenges each part faces include:

When a standard light source shines from above, the upper portion of the sheet music, being closer to the light, appears overly bright, while the lower portion is too dim, creating harsh glare spots on the music. To effectively illuminate the sheet music, the upper section’s brightness must be reduced while enhancing the lower section's lighting. This balance ensures even illumination across the entire sheet.

Additionally, traditional desk lamps, limited by their short lamp heads, cannot cover the full 122 cm width of a piano keyboard. Achieving the widest possible illumination with a compact lamp head is another significant challenge in piano lighting.

Introducing BenQ STEREO-Light™ Technology

An Innovative Solution for Even Illumination of Sheet Music and Piano Keys

STEREO-Light™ technology splits the light into two beams, one dedicated to illuminating the sheet music and the other to lighting the piano keys. Using reflective surfaces and multi-layered focusing techniques, this technology precisely controls light distribution. It has been integrated into BenQ’s PianoLight series, ensuring even illumination of both sheet music and keys while reducing glare.

For instance, in the PianoLight R, the principle of using a parabolic mirror—similar to a reflecting telescope—is applied. The LED light shines directly onto a high-reflective aluminum surface, forming a light cup that evenly illuminates the sheet music from the middle of the lamp head. Meanwhile, convex lenses on either side of the lamp head direct the second beam of light towards the far ends of the piano keys, ensuring all keys meet the recommended 300 lux illumination standard from the Lighting Association.

How BenQ Achieves Superior Piano Lighting

The Perfect Combination of Optical Simulation and Practical Testing

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Optical Simulation

During the development process, the BenQ team collects data from various major piano brands and conducts hundreds of optical simulations to determine the most suitable curvature and angles for lighting. For example, with the L-shaped reflective aluminum sheet in the PianoLight Grand.

The BenQ team analyzed sheet music stands from grand piano brands such as Yamaha, Steinway, and Roland. They found that the tilt angle of the sheet music generally ranges between 60 to 80 degrees. Subsequently, optical simulations were performed within this range to find the optimal tilt angle and opening angle combination for the L-shaped reflective sheet. After thorough testing, they concluded that the best combination is a 100-degree tilt with a 27.5-degree opening angle!

Model Testing

To verify the optical simulation data, the BenQ team created various physical models and conducted tests to ensure that the simulations matched real-world performance.

Efficient Material Design

BenQ's light cup structure uses high-reflective aluminum, coated with silver to achieve a 97% reflectivity, significantly enhancing the LED’s light output efficiency. In addition, the surface is treated with a special textured structure that diffuses incident light, spreading the light evenly without creating harsh spots.

BenQ's optical team also designed a custom convex lens, fine-tuned through computer simulations to achieve the ideal curvature radius, further boosting lighting efficiency by 23%.

A Uniform Lighting Solution that Exceeds Auditorium Standards

The STEREO-Light™ technology, born from precise simulations and specialized materials, allows BenQ piano lamps to achieve a luminance of over 530 lx at the center and corners of the sheet music, while also ensuring that the key illumination exceeds 300 lux. This performance surpasses the lighting standards defined by the American National Standards Institute (ANSI) for auditoriums, which require a horizontal working surface to reach 300 lux, a vertical surface to achieve 500 lux, and a light ratio of less than 2:1 between the two to avoid discomfort caused by uneven brightness and glare.

From Upright Pianos to Platform Pianos

The structure of platform pianos presents greater challenges for light design. Since the position of the sheet music stand is further away from the keys compared to electronic or upright pianos, the first generation of STEREO-Light was unable to meet our lighting requirements.

The new generation of STEREO-Light™ is applied to the recently launched PianoLight Grand. To accommodate the structure of platform pianos, the BenQ team added an L-shaped reflective aluminum sheet while retaining the original light cup and convex lens structure. This new design allows the light source to be directed toward the back of the sheet music area. By further splitting the light source into two beams, the BenQ PianoLight Grand can comprehensively illuminate the entire piano playing space, making it suitable for various types of pianos, including electronic, upright, and platform pianos.

L shape refector of BenQ PianoLight Grand

What Makes the Light of BenQ PianoLight Different?

Standard desk lamps are designed to illuminate horizontally placed books.

using traditional desk lamps on an upright piano can cause uneven lighting and direct glare

Using a desk lamp to light up sheet music can result in uneven brightness, with the top being too bright and the bottom too dim, while also causing light to shine directly into the eyes.

BenQ PianoLight provides even lighting on sheet music as well as prevent direct glare

BenQ's piano lamps reduces the brightness in the upper part of the sheet music and enhances the lighting in the lower part, ensuring the entire sheet music is evenly and comfortably lit.

Our Exclusive Patented Technology

The BenQ PianoLight series has secured five optical-related patents worldwide, showcasing our innovation and leadership in piano lighting technology.

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