LED Backlight

The Great Future of LED TV(4): The Trend and challenges of LED TV

ivan — Wed, 15 Oct 2008 02:28:51 +0000

The main issue LED TV faces is still high costs, therefore the manufacturer usually place LED TV at the top class of TV products. Besides, with more than 1000 LEDs being the backlight, how to maintain the equality and reliability remains a big issue.

At the moment the retail price of LED TV is still much higher than the traditional flat TV. For example, according to the research of Witsview on the retail price of TVs in the North America, while comparing the retail price of 40-inch and 46-inch LED TVs with that of Full HD flat TV, the price difference is still 30% or more, though it has narrowed since the debut of LED TV. Now there are few productized LED TVs in the market, so we take Samsung’s LED TV which launched in 2007 as the sample of our research.

Since in 2008 there are new LED TVs to enter the market, the price of Samsung’s 2007 model shall fall rapidly. If we take new 2008 models into calculation, the price difference between LED TV and HD flat TV would widen.

Figure- 1 The comparison of prices of 40-inch flat TV and LED TV in the north America
Source: LEDinside

Figure-2 The comparison of prices of 46-inch flat TV and LED TV in the north America

Source: LEDinside

Take the Direct Edge(top view) LED TV for example, its main appeal is the quality of picture and the high contrast ratio, but it needs a big number of LEDs, therefore while it can lower down its energy consumption relies on its manufacturer’s design ability. If the consumer favors TVs with high contrast ratio, in fact they can choose plasma TV, but not necessarily LED TV. Regarding to the Side Edge LED TV, it may attract consumers who take the shape of TV as a chief consideration, but usually we don’t need to move TV frequently, therefore a cheap price is still prior to the thinness and lightness of it.

As a whole, at the moment LED TV can still only be accepted by the technology fanatic and the top layer of consumers. LEDinside predicts that the shipment of LED TV in 2008 is still less than 1% of the global total shipment of TV. It’s only after 2010, when the technology of LED backlighting matures and the costs falls largely, the penetration rate of LED TV will rise gradually.

Figure-3 The prediction of LED TV’s penetration rate

Source: LEDinside

Previous: The Great Future of LED TV(3)--Thinner、Better Picture Quality and More Energy Saving

The Great Future of LED TV(3)--Thinner、Better Picture Quality and More Energy Saving

ivan — Mon, 06 Oct 2008 01:55:55 +0000

Observing the strategies of those main LED TV manufacturers one can find that all LED TVs are made with 40-inch or larger panels. This is because the price of the U-shape CCFL for 32-inch panels is very cheap, which is half or two-third lower than the price of the LED back-light. Therefore the manufacturer is more willing to adopt LED back-light in the big-screen TV, in this way they can aim at the top layer of consumers .

Regarding to the back-lighting technology, it's separated into 「Direct Type」 and 「Edge Type」. At present most LED TV adopts the Direct Type technology, which puts the back-light directly in the back of the panel, and uses the diffuser to diffuse and equalize the light.

The Edge Type technology puts LEDs around the panel and uses transmitters to project the light equally on the back of the panel. The Edge Type can reduce the number of LEDs while compared to the Direct Type. For example, making a 46-inch LED TV with the Direct Type technology, you need 1100 to 1300 pieces of LED, but with the Edge Type you only need 400 to 600 pieces.

Regarding to LED technology, most manufacturers formed their LED back-light with red, green, and blue LEDs. They combine the Direct Type technology with the Local Dimming technology to turn bright or dark the individual parts of the picture, so as to make the contrast more conspicuous. Besides, some manufacturers use RG Phosphor and blue LED to produce white light, in this way they can reduce the number of LEDs and bring the costs down. White light also has better result than the combination of blue LED and YAG.

In the future, the main stream of LED TV will go in two direction, either high-definition or ultra-thin. At the moment most LED TVs have walked in the first direction. With RGB LED and the combination of Local Dimming and Direct Type, the contrast ratio is improved. Many producers claim that the dynamic contrast ratio of their LED TV can be as high as 1000000:1 and even higher. The 46-inch LED TV put an emphasis on the quality of picture and contrast, and it's priced very high to aim at the top layer of consumers.

Another direction is ultra-thin, which possibly combines RG Phosphor and blue LED, and adopts the Edge Type back-lighting technology. In this way there would be no CCFL or LED in the back of the panel, thus the TV can be made ultra-thin, and the costs can be reduced as well because the Edge Type requires less LEDs. But the Edge Type can not adjust the darkness or brightness in some areas, so it would have to sacrifice the contrast ratio and the degree of saturation.

As a result, in the future main manufacturers may produce Edge Type LED TV with 46-inch or smaller panels, which will be the main stream. In the contrast, they will also produce Direct Type LED TV as a high-end model to target a different market.

Previous: The Great Future of LED TV(2)-- The maturity and productization of LED TV Technology

Next: The Great Future of LED TV(4): The Trend and challenges of LED TV

The Great Future of LED TV(2)-- The maturity and productization of LED TV Technology

ivan — Wed, 01 Oct 2008 05:08:16 +0000

In the IFA 2008, many manufacturers introduced LED TVs to show their capability of combining LED and TV technology.

Samsung

For example, Samsung introduced the A950 series, which supports Full HD(1920*1080) with screens made 46 or 55 inches, and adopts LED back light, which can control the brightness more efficiently.

Sony

Sony also displayed LED TVs made with two different LED back-lighting technologies. One of them called X4500 series, which adopts 「Direct Type」 LED back-light and comes with screens made as 46 and 55 inches. The X4500 series adopts Sony's exclusive technology of LED Back-lighting, which is called TRILUMINOS RGB. TRILUMINOS RGB changes the result of traditional RGB LED back-light, which arranges the colors of red, green and blue in a special way, pushing up NTSC to 102% and the dynamic contrast ratio to 1000000︰1.

Another LED TV from Sony is called ZX1, which adopts the 「Edge Type」 LED back-light and 40-inch panel, reducing the thickness of its LCD panel to 9.9mm only, and thus becomes the thinest big-screen TV in the industry. ZX1 weights only 12.2 kilograms, contains 120Hz MotionFlow scanning technology, x.v.Color and BRAVIA Engine 2 picture processing technology. But in order to make the ZX1 ultra-thin, Sony has sacrificed some features, such as the static contrast ratio, which is only 3000:1, and the ZX1 only has one HDMI. It's priced at 490,000 yen(4,600 USD).

LG didn't show its LED TV in the IFA this time, but already launched the LG90 series in Korea, which adopts 47-inch panel and LED back-light. The contrast ratio of LG90 series is as high as 1000000: 1, while its energy consumption is only 70% of that of other LCD TVs with similar screen size. LG90 series also adopts 120Hz technology, which is combined with the high efficiency of switching from LED back-light to lift up the level of definition for dynamic pictures.

Sharp

Sharp's LED TV is named Aquos-XS series, which comes with 65 or 52-inch panel, 1000000:1 contrast ratio, and 105% NTSC. LED back-light makes the thinest place of Aquos-XS only 23mm. Aquos-XS is scheduled to launch in October 2008.

Philips

The LED TV from Philips is 42PFL9803, which adopts 42-inch screen and LED back-light,and is the first TV that utilizes Philips' LED LUX dimming technology. 42PFL9803 has 128 sets of LED(1152 in total) which are separated into 8 rows, and each set contains 9 LEDs that can individually shift to dark, so every pixel can be controlled accurately to increase the performance of dark color. Philips claims that the picture performed in its 42PFL9803 has better quality than that in the plasma TV, because the dynamic contrast ratio of 42PFL9803 is as high as 2000000:1.

Previous: The Great Future of LED TV(1)-- LED TV became focus in the IFA 2008

Next: The Great Future of LED TV(3)--Thinner、Better Picture Quality and More Energy Saving

The Great Future of LED TV(1)-- LED TV became focus in the IFA 2008

ivan — Wed, 24 Sep 2008 05:06:27 +0000

Why use LED backlight？

A few days ago in the IFA 2008 hosted in Berlin，many of the branded TV manufacturers introduced LED-backlighted TVs(LED TV)，aimed at the top layer of customers. Some leading manufacturers such as Sony and Samsung already introduced LED TV in 2006，but with the costs of LED have decreased and the LED technology has progressed rapidly, LED TV has moved toward a real product rather than just a demonstration of technology.

The structure of LED backlighting is fundamentally the same with that of CCFL, but CCFL produces light in the form of 「rays」 and LED in the form of 「spots」, which is the main difference. So what is the reason that the leading TV manufacturers shift to LED from CCFL? Generally LED has some distinguishing features as follows：

The 「spot」 form of LED light can individually adjust the brightness and contrast in different areas. It can also increase the gray levels of LED monitors, broaden the color saturation(NTSC >100%), heighten the distinction between dark and bright, and improve the richness of the picture.
LED spot light can switch on or off rapidly, due to this LED backlight has a longer life than CCFL, and its quick reaction also improves the quality of an active picture by reducing hazy or sway.
LED backlight is smaller, and can be made straight down or on the left side or right side, helping making the TV slimmer.
LED TV is a real green product. It gives no radiation, contains no mercury, and lives longer. It can also reduce the energy consumption for 30％ up.

However, compared with CCFL, LED TV still has a long way to go. For example, LED backlight requires a big number of bulbs, how to set up these bulbs without losing the equality and balance remains a question. Besides, there are still problems regarding heat cooling, lighting efficiency, and cost reduction.

Next: The Great Future of LED TV(2)-- The maturity and productization of LED TV Technology

LED Backlight reduces LCD Monitor Power Consumption by 28 %

sarafan — Tue, 16 Sep 2008 06:02:54 +0000

Recently, Eizo Nanao Corp announced the "Eizo FlexScan EV2411W-H" 24.1-inch LCD monitor that uses white LEDs as its backlight source.

This is the first time that Nanao has released a white LED-backlit LCD monitor. The monitor will go on sale from Oct 16, 2008. There is no suggested retail price, but the monitor will be sold on the company's "Eizo Direct" direct marketing website at a price of ¥84,800.

According to Nanao, through the adoption of the LED backlight system and the luminance sensor, the company succeeded in realizing nearly a 28% reduction in power consumption compared with the previous model, the "EIZO FlexScan S2401W," which uses a cold cathode fluorescent lamp (CCFL) backlight system.

The new product adopts an edge type backlight system, in which lamps are positioned on both the top and bottom sides of an LCD panel. A total of 160 white LEDs are used with 80 LEDs of them positioned on each side. The monitor also features an "Auto EcoView" function that automatically adjusts the backlight's luminance in accordance with the external brightness detected by the luminance sensor equipped on the bottom of the monitor.

The monitor supports an "EcoView Index" function that displays the power saving efficiency on the LCD monitor at the press of a button. In addition, the monitor supports "EcoView NET," an application that enables a single client PC to arrange settings, including the power supply and the display luminance, of multiple LCD monitors manufactured by Nanao. EcoView Net can only be run on Windows Vista. The company is planning to start providing the software for free from November 2008.

LED driver upgrades LCD backlight for media player apps

sarafan — Tue, 16 Sep 2008 03:21:58 +0000

Recently, ON Semiconductor has released the NCP5890, a lighting management device that integrates LCD backlighting, fun light controls and ambient light sensing in a 3mm x 3mm x 0.55mm µQFN-16 package. It targets compact smart phone and portable media player applications.

With its 30V output capability, the device drives LEDs in series to achieve homogeneous backlight over the LCD screen. At the same time, it controls three sets of white LEDs or RGB LEDs to create light patterns on keypads or chassis in a unique combination with backlighting. The driver also extends battery life by adjusting the backlight current based on the ambient light level.

Having high overall power efficiency of up to 90 percent at 1.3MHz oscillator frequency, the NCP5890 inductive boost LED driver renders up to 30V at output. It can sustain eight LEDs in series for LCD backlight and fun lighting. The device supports ambient light sensing, a feature needed in smart phones to lower power use and increase user comfort.

The NCP5890 also has a built-in gradual dimming that produces fade-in and fade-out effects. Both ambient light sensing and gradual dimming are automated built-in functions that can be activated with I2C commands. The device backs I2C protocol with two separate address options. The integrated driver also stretches battery power with a true cut-off function that limits the leakage output current in shut-down mode.

Freescale illuminates LED growth markets

aber — Mon, 15 Sep 2008 09:47:06 +0000

Addressing the burgeoning market for energy-saving, environmentally friendly light-emitting diode (LED) technology, Freescale Semiconductor is now sampling the first LED backlight product in its power management IC portfolio.

The new 10-channel MC34844 white LED driver IC is designed for LED backlights in notebook computers, as well as in flat-panel monitors with screen sizes ranging from 10 inches to 27 inches.

According to IMS Research, the market for semiconductors used in backlighting applications, including LED driver ICs, is expected to grow from $1.1 billion (USD) in 2008 to $2.0 billion in 2012. Currently, LED backlights are prevalent in smaller liquid crystal displays (LCDs) for cell phones, GPS devices and PDAs.

However, LEDs are now being implemented in larger LCD modules used in laptops, monitors and large-screen TVs.

"We expect the market for LED backlighting in notebooks, monitors and TVs to grow strongly," said Jamie Fox, a market research analyst for IMS Research. "In notebooks in particular, rapid growth is widely expected from 2008 to 2010."

"LED backlighting is a disruptive technology that will spur innovation and growth in the LCD market and enable more energy-efficient and environmentally friendly LCD displays," said Arman Naghavi, vice president and general manager of Freescale's Analog, Mixed-Signal and Power Division. "As a leading analog supplier, Freescale is well-positioned to deliver advanced driver ICs for LED backlighting applications. The market for LED backlights offers untapped potential as growth opportunities expand from laptops and monitors to LCD TVs and automotive, consumer and industrial lighting applications."

Energy-efficient, mercury-free

LED technology offers many advantages over conventional cold-cathode fluorescent lamp (CCFL) lighting systems, which are widely used in conventional LCDs. LED backlighting enhances the user viewing experience, offers more flexible backlight architectures and enables thinner display designs.

Additional benefits of LED backlighting over conventional CCFL technology include higher efficiency (more light at a given power), reduced power consumption, a five-fold longer lifespan, enhanced durability, and up to 100 times better contrast ratios for clearer definition on screen.

A key benefit of LED technology is that it is free from mercury, a substance known to be toxic to humans. Mercury is a key material in CCFL lighting systems, which are used in 99 percent of existing LED TV displays. In Europe, the European Directive on the Restriction of Use of Certain Hazardous Substances in Electronics (RoHS) has mandated that manufacturers must move to mercury-free LEDs.

UK government to invest in lighting R&D projects

sarafan — Fri, 12 Sep 2008 05:55:51 +0000

Recently, The UK Technology Strategy Board (TSB) has announced funding for twelve innovative research projects to accelerate the development of more energy-efficient lighting, lasers and displays. The R&D projects are intended to help British manufacturers to stay ahead of international competition - and contribute to the UK's climate change goals.

The projects will see businesses working collaboratively with other businesses and academic institutions to develop and deploy technologies in areas such as more efficient LEDs, laser diodes, white-light fibre lasers and holographic optics. Other projects will see the integration of new and existing component technologies into working systems. The total value of the twelve projects is in excess of GBP15.5 million, with the Technology Strategy Board contributing over GBP7m of this figure. The Engineering and Physical Sciences Research Council (ESPRC) is contributing nearly GBP1m to five of the projects.

Some of the funded LED projects are listed below:

Title: LED lighting for the 21st Century [LL21C]
Summary: The LL21C consortium will demonstrate a novel electrically isolated ultra thin GaN LED (EIUT LED) capable of 95% light extraction and designed for general lighting applications.
Partners: PhotonStar LED, University of Cambridge

Title: Low Cost Holographic Optical Elements for Next Generation Lighting Systems: NAHO (Nano Aligned Holographic Optics)
Summary: The NAHO project will develop the technology for production in the UK of edge-lit lighting devices for use in buildings, based on silver halide holographic optical elements (HOEs) illuminated by state-of-the-art LEDs. These will increase efficiency of existing LED flat lighting screens from 45% up to 90% and enable a significant reduction in energy use.
Partners: Harman Technology Ltd, De Montfort University, Concord (Part of Havells-Sylvania)

Title: Enhanced Display Viewability using High Efficiency Advanced LED Backlight Arrays (ENDVIEW)
Summary: This project will deliver enhanced display viewability of dynamic images through the application of high performance LED arrays and novel optics systems.
Partners: GE Aviation Systems, University of Greenwich, University of Abertay Dundee, National Physical Laboratory, Thin Film Solutions Ltd, Raymarine plc, NCR Financial Solutions Group Ltd, Design LED Products Ltd

Title: MENDIPs - Manufacturing emissive nanotechnology devices in polymers
Summary: MENDIPs will create a sustainable controlled pilot manufacturing capability for the production of PLED devices. MENDIPs will also facilitate new auto/architectural/medical device applications as a result of reproducible and repeatable manufacturing processes being created.
Partners: PolyPhotonix, Sanko Gosei Ltd, Centre for Process Innovation Ltd

The TSB's Chief Executive, Iain Gray, said: "We are committed to stimulating the development and deployment of technologies which, as well as benefiting society, also represent major business opportunities for the UK. Advanced light and laser sources are an area where the UK has an excellent reputation for world-class research activity, a healthy industrial base and the capability to exploit the results globally."

LED driver IC to target 10-27 inch LCDs

sarafan — Fri, 12 Sep 2008 03:11:59 +0000

Recently, Freescale Semiconductor is sampling the first LED backlight product in its power management IC portfolio. The 10-channel MC34844 white LED driver IC with an integrated boost converter is designed for LED backlights in notebook computers, as well as in flat-panel monitors with screen sizes ranging from 10 inches to 27 inches.

According to Freescale, the MC34844 IC, housed in a lead-free, 32-pin 5 x 5 x 0.8-mm TQFN package, is reportedly the industry's most compact LED backlight driver IC for notebook and monitor applications. Capable of driving up to 160 LEDs in 10 parallel strings, the highly integrated device provides greater LED control capabilities than any other single-chip solution currently available.
Using the device's I2C/SMBus interface, developers can program the LED current, PWM frequency and PWM duty cycle for the LEDs. Multiple devices can be synchronized for driving more LEDs. The MC34844 is designed to remove the burden on the controller for PWM generation and to eliminate the need for PWM signals to travel through the printed circuit board, which can cause noise and electromagnetic compatibility performance issues.

In addition, the MC34844's pulse-width modulation (PWM) generator supports LED dimming, a feature that helps improve picture quality and enables a long screen life. The device also is designed to deliver consistent performance over the lifetime of the LEDs by compensating for optical and temperature degradation.

The MC34844 offers an input voltage range of 7 V to 28 V and an output voltage of up to 60 V. The LED driver delivers up to 55 mA LED current per channel. It also features dynamic headroom control to improve device efficiency and a 3.5-A integrated boost. Protection features include user-programmable over-voltage protection, LED open failure detection and OTP/OCP/UVLO lockout.

Freescale samples the first LED backlight product

sarafan — Tue, 09 Sep 2008 03:13:53 +0000

Freescale Semiconductor has entered the LED market, and announced that it is sampling the first LED backlight product in its power management IC portfolio. The 10-channel MC34844 (pictured) white LED driver IC is targeted at LED backlights in notebook computers, as well as in flat-panel monitors with screen sizes ranging from 10 inches to 27 inches.

“LED backlighting is a disruptive technology that will spur innovation and growth in the LCD market and enable more energy-efficient and environmentally friendly LCD displays,” said Arman Naghavi, VP and general manager of Freescale’s analog, mixed-signal, and power division, in a statement. “The market for LED backlights offers untapped potential as growth opportunities expand from laptops and monitors to LCD TVs and automotive, consumer and industrial lighting applications.”

According to Freescale, key benefits of LED technology over conventional cold-cathode fluorescent lamp (CCFL) lighting systems include higher efficiency, reduced power consumption, a five-fold longer lifespan, enhanced durability, and up to 100 times better contrast ratios for clearer definition on screen. LED technology is also free from mercury, a substance known to be toxic and often restricted or banned by current environmental regulations like ROHS. With the launch of its LED backlight driver IC portfolio, it plans to expand into growing backlighting markets, such as large-screen digital TVs and commercial lighting. The Austin-based company expects to announce LED backlighting solutions for LCD TVs in Q1 2009. Also in 2009, the company expects to pursue the LED lighting market for automotive, commercial, and residential applications.

The MC34844 LED driver IC can drive up to 160 LEDs in 10 parallel strings and includes pulse-width modulation (PWM) generator support for LED dimming. The device also is designed to deliver consistent performance over the lifetime of the LEDs by compensating for optical and temperature degradation. Using the device’s I2C / SMBus interface, developers can program the LED current, PWM frequency, and PWM duty cycle for the LEDs, Freescale said. Multiple devices can be synchronized for driving more LEDs.

Citing data from IMS Research, the market for semiconductors used in backlighting applications, including LED driver ICs, is expected to grow from $1.1 billion in 2008 to $2 billion in 2012. Freescale is currently sampling the MC34844 LED driver IC for laptops and monitor applications. Broader market availability is planned for Q4. The suggested resale price of the MC34844 in 10,000 quantities is $1.44.