In the world of consumer display technologies, the battle between LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode), and to a far lesser extent, direct view micro RGB LED (Red, Green, Blue Light-Emitting Diode) has been ongoing, each with its own strengths and weaknesses.
For outdoor advertising applications OLEDs are not at all a via technology due to their relatively low APL (average picture level brightness … < 1000 nits), relatively high specular (mirror) reflection, and susceptibility to catastrophic and irreversible image retention when displaying relatively static images (i.e., ads).
This leaves only high bright LCDs and direct view micro RGB LED as viable outdoor street furniture Digital Out of Home (DOOH) technologies.
Manufacturing Resources International’s (MRI’s) decision to stick with LCD technology over direct view micro RGB LED is a practical one, driven by a combination of image quality, power consumption, cost-effectiveness, and reliability.
We stand by our commitment of using commercial-grade, high temperature, outdoor rated LCD cells in our products and there are several important factors that allow us to achieve the industry’s only 10+ year lifetime performance.
1. Image Contrast in Direct Sun:
By the very nature of the technology, direct view Micro RGB LEDs inherently exhibit excessive diffuse reflection (10 to 100 times greater than LCDs). This results in very poor image/color contrast when viewed in direct sun. The colors are muted and dull. Blacks are not black, but various shades of grey. At night, direct view Micro RGB LEDs look great. During the day … not so much.
About MRI
Manufacturing Resources International was born in 2004 as an evolution from Avionic Displays Corporation (ADC) and American Panel Company (APC). ADC carries on today as Elbit Display Systems and APC carries on as Mercury Systems, both leaders in their field of LCD based displays used in the world’s military airborne and ground-based systems, as well as commercial and business aviation. With the lessons learned from these “failure-not-an-option” harsh environments, MRI branched off into the world of Digital Out Of Home (DOOH) advertising with the BoldVu® product line.
LED stadium/arena score boards, as well as building and roadside billboards using direct view RGB LED can somewhat mitigate the extremely high diffuse reflection problem by using physical micro louvers (like venetian blinds) between successive rows of LEDs. These displays are viewed from below at relatively far distances, with the observer looking up. LED pitches are relatively large (often 6mm or greater). This allows the individual rows of LED to be “shaded” from the sun by the physical micro louvers or “visors”. None of this is possible with street level micro RGB LEDs. Hence the unacceptably poor image quality of street level micro RGB LEDs in direct sun.
No technology yet discovered outperforms properly implemented LCDs for direct solar exposure daylight image quality.
BoldVu® LCD based products, with their 3500 nit APL brightness, combined with < 1% specular and <0.01% diffuse reflectance, provide world leading image performance in any lighting environment from direct sun to total darkness.
BoldVu® LCDs are then back lit with an array of direct-lit, mini LEDs which are blocked dimmed to create jet blacks and bright, vivid, saturated colors regardless of whether the display is experiencing direct sun during the day or pitch black during the night.
2. Image viewing angle:
While direct view RGB LEDs may have comparable viewing angles to BoldVu® LCDs in low light environments, RGB direct view LED technology suffers severely with color saturation and image contrast in sunlight. Additionally, unlike roadside/building billboards and stadium score boards, street level RGB LEDs must be covered by IK10 rated, impact resistant glass. The glass is necessary to protect the RGB LEDs from vandalism. The addition of the glass in front of the RGB LED array unfortunately adds costs. Under direct sunlight, the cover glass then creates a thermal greenhouse making the LEDs excessively hot, resulting in the additional costs and power consumption to add a cooling scheme. The coverglass, due to the added reflection, further degrades an already low contrast/low color saturation direct view RGB LED daylight image.
Some outdoor LCD based displays offer poor off-angle viewing. Those that employ infrared (IR) and/or ultraviolet (UV) optical filters on the coverglass in front of the LCD to combat overheating from solar exposure can look like red or blue mirrors, totally obscuring the displayed image when viewed off-angle. Other LCD products may also use excessive optical collimation films in their backlight to achieve higher on-axis image luminance while sacrificing luminance and image contrast when viewed off-axis.
Not so with BoldVu® all weather, direct outdoor LCD based products. Our international, multi-patented cooling system, CoolVu® , provides the coolest LCD temperatures in the industry, even when exposed to extreme ambient temperatures and direct solar exposure, without the use of image degrading “solutions” such as IR and/or UV reflection technologies or excessive on-axis backlight optical collimation. Combined with our color matched high efficiency mini-LEDs, direct dynamic block dimming backlight, and MRI custom backlight optical stack, BoldVu® has the widest viewing angle, highest image contrast and color saturation of any competing products, at absolutely the lowest power … including direct view RGB LEDs.
3. Image Resolution:
Street level displays need high resolution as they can be viewed from a distance as close as an arm’s length away. Today’s BoldVu®
LCD products provide pixel pitches ranging from 0.63 mm for the FHD 55” to 0.37 mm to 0.56 mm for the 65” to 98” UHD units.
Realistically, today’s highest resolution direct view RGB LEDs range from 1.2 to 2.5 mm pitch. This means that for street level displays, direct view LEDs cannot achieve FHD or UHD resolutions. The image will look very pixelated or grainy.
Some display technologies are prone to temporal flicker where the human eye perceives a video image as “breaking up”, “jumping”, “flickering” or looking “incomplete”. This can be distracting or even nauseating.
Temporal video display flicker is generally caused when the retina of the eye physically moves during the rendering of a video image frame. This can happen as the retina of the eye “jiggles” while walking down a sidewalk, riding in a moving car, eating popcorn, chewing on ice, etc., while looking at a video image.
BoldVu® LCD based products do not exhibit temporal flicker. This is by design. First, by the inherent nature of the “Active Matrix” LCD technology, every pixel of the video image is held “constant” for the entire duration of each video frame. Second, each logical block of the mini-LED backlight behind the BoldVu® LCD is also held constant and directly driven for the duration of a video frame. Third, the “refresh” or update of each logical block is synchronized with the “refresh” or update of each video frame on the LCD. The result is no beating frequencies of light between the LCD and the backlight, and the backlight and LCD image are being held constant for the duration of each video frame.
Not all LCD displays operate this way. Often LCD refresh and backlight refresh are not synchronized. As mini-LED block counts rise, block scanning, as opposed to the BoldVu® direct drive of each backlight block, is becoming a more “economical” way to implement the backlight. Either of these approaches, separately or combined, can introduce temporal flicker in LCDs. Not so with BoldVu®.
All direct view micro RGB LED displays are extremely prone to temporal flicker. These displays are “passive matrix” or scanned over time. This means that individual LEDs forming the image may be turned “on” for as little as 1/64, or less, of a “full” image frame. This has many adverse effects on the display:
a. Results in temporal flicker. As the technology matures, the image refresh rate continues to rise (3840 Hz or higher) in an effort to mitigate the flicker.
b. The strobing of the RGB LEDs significantly increases the peak current to each LED chip, degrading longevity.
c. The increased peak currents required to strobe the LEDs at ever increasing refresh rates increase the IR power losses, making the mini RGB LEDs run hotter and consume more power …and degrade reliability.
By comparison BoldVu® is designed to direct drive each mini-LED backlight block to minimize LED currents, reduce LED stress, reduce IR power losses, maximize LED efficiency, and prolong product life. Hence BoldVu®’s industry leading low power consumption, cool operation, and exceptional 10+ year maintenance of full display luminance!
5. Power/Cost:
The tighter the direct view RGB LED pitch, the lower the luminance (even less daylight image quality), and the higher the power consumption and cost. Both power and costs go up roughly as the square of the difference in LED pitch (i.e., dropping the LED pitch from 2.5 to 1.2mm will increase both power and cost by approximately (2.5/1.2)^2 = 4.34 x). Power for the direct view RGB LED displays will range from 2X to 4X times as much as a BoldVu® LCD.
6. Reliability:
Outdoor LCDs have gained an underserved reputation of being unreliable and short lived. This is true for any displays (LCDs or micro RGB LEDs) that are not properly sealed, cooled, monitored, and managed.
BoldVu® by MRI has proven this does not have to be the case. With more than 3 decades of experience and knowledge, 17 generations of product evolution, and nearly 30,000 BoldVu® digital display faces deployed globally in every imaginable environmental and weather extreme, BoldVu® is the time tested, proven, long lived outdoor display product solution.
BoldVu® Gen 17 is the only globally available outdoor display product that comes with a performance guarantee. When properly maintained by MRI through a service level agreement (SLA), BoldVu® is guaranteed to maintain day 1 visual performance (i.e., brightness, color saturation, image contrast, viewing angle, etc.) when operating 24/7/365 for the term of the SLA up to 10 years.
Direct view RGB mini-LED displays are still relatively immature as a technology and industry. RGB LEDs are prone to individual red, green or blue failed, stuck on or stuck off pixels. Stuck off is not too offensive, until they become clustered or excessive, as they are black. Stuck on is another story, particularly at night, as they are stuck typically at full brightness.
RGB LED displays are formed by many small blocks or tiles abutted next to each other. Each tile must be calibrated to match adjacent tiles in color, luminance, and grey scale. Poor calibration and/or replacement of individual tiles due to failures over time result in a “patchwork quilt” look to the overall image.
When new, as discussed above, the diffuse reflection of RGB direct view LEDs is poor, degrading black levels, image contrast and color saturation when viewed in daylight. As the direct view RGB display ages the diffuse reflection, and therefore image quality, becomes progressively worse. Solar exposure, excess temperatures, oxidation, electrostatic attraction of airborne dust and/or dust deposits left behind from evaporating rainwater degrade the “black” materials surrounding each RGB LED turning them ever lighter shades of grey.
RGB direct view LED displays, as the name implies, are made up of millions of individual red, green, and blue LEDs. Each color has a different rate of degradation. When new, RGB LED may look very good, with a pleasing white balance. However, as they age the blue LEDs in particular diminish more rapidly than the red and green, resulting in a shift of the entire display color spectrum towards yellow.
Beginning with BoldVu® Gen 17, no more:
a. LCD cell breach (i.e., black circles or bubbles in your display image)
b. Gravity mura (i.e., brown to yellow discoloration across the bottom of your display image)
c. LCD solar clearing (i.e., blackening of areas of the LCD when exposed to the sun)
d. Browning/Yellowing of the display image from excessive heating of the LCD and/or backlight components
e. Dust or moisture ingress I.e., all BoldVu® products are IP66 sealed with 24/7 internal air pressure sensing and reporting via internet communications)
f. Black images when viewer through polarized sunglasses (excludes BoldVu® 98” products)
g. Photoconductivity (i.e., areas of the displayed image turning milky white/dark grey when exposed to direct sun)
h. Image retention or sticking, so long as static content is not displayed for prolonged periods of time and the BoldVu® LCD Rejuvenation pattern is invoked daily during “off” hours
In conclusion, BoldVu® by MRI’s choice of LCD technology over LED/OLED is a strategic decision based upon a combination of factors that prioritize image fidelity, preservation of image fidelity over 10+ years of operation, cost-effectiveness, power efficiency, reliability, and technological maturity.
While a consumer OLED TV may wow at home, it is not a technology ready for 24/7/365 use in exposed outdoor environments. Also, while the various display technology manufactures may expound upon the “wow” factor of the large area micro RGB LED direct view displays, they downplay the costs, power consumption, reliability, or even viewability in a brightly lit room … and certainly do not see them as a viable outdoor all-weather display.
BoldVu® by MRI displays are purpose built from the outset using only commercial grade, high temperature LCD cells in an IP66 sealed (no dust or moisture intrusion) chassis achieving superior direct-sun viewable sharpness, high-contrast color, and power efficiency that is maintained throughout the lifetime of the product.
Not only is BoldVu® the highest image quality, longest lived, most reliable, lowest power, quietest, maintenance free (no air filters), all weather, direct outdoor street level display product available today, it is also by far, the lowest total cost of ownership (TCO). This lowest TCO is based upon the sum of the acquisition cost, installation cost, maintenance cost, longevity (no need for replacement for 10+ years), and cost of power over the installed life of the display.
In short, BoldVu® is THE ideal street level DOOH solution!
