National Policy on ICT in School Education

DISPLAY TECHNOLOGIES IN THE CLASSROOM

Factors to Consider

ICT India White Paper

Submitted By

Texas Instruments Inc.

TABLE OF CONTENTS

EXECUTIVE ABSTRACT..................3

CLASSROOM DESIGN: THE RIGHT WAY TO INTEGRATE COMPUTERS .........4

PROJECTION 101 – UNDERSTANDING PROJECTOR TECHNOLOGIES...........6

AFFORDABILITY: ASSESS THE TOTAL COST OF OWNERSHIP (TCO)............9

RELIABILITY: COLOR DECAY AND DUSTY CONDITIONS.........10

IMAGE QUALITY: ENSURING CLARITY FOR THE LONG TERM.........11

DLP TECHNOLOGY AT PLANO, TEXAS (USA) INDEPENDENT SCHOOL DISTRICT.............12

EXECUTIVE ABSTRACT

Initiatives to bring effective computing technology to classrooms often overlook an important enabler: effective projection display to give teachers and students a focal point for instruction, learning, and presentation. DLP® and LCD – the two dominant imaging technologies for computer projection – offer different approaches with various benefits and drawbacks. Educators should give careful consideration to three important factors.

1. Affordability analysis should emphasize the total cost of ownership over the lifetime of the device, and factor in various maintenance and replacement costs.
2. Reliability studies should carefully consider the expected life of the different technologies.
3. Schools should also study the quality of the image that’s projected – and how that quality is sustained over many hundreds or thousands of hours of use.

CLASSROOM DESIGN: THE RIGHT WAY TO INTEGRATE COMPUTERS

While most education experts agree that integrating computing technology into classrooms can yield compelling benefits, implementations have not always delivered on the promise of an enhanced teaching experience. That’s because, too often, previous classroom-computing deployments have actually detracted from the education process by removing the central point of focus and shifting attention away from the teacher at the front of the classroom. With many PC-based lessons, children focus on their own PC and the teacher becomes a secondary figure in the lesson. Not surprisingly, many educators have recognized that computer projection is an essential requirement to successfully integrate computing into the curriculum.

However, before bringing a projector into a classroom setting, it’s important to step back and analyze how to best use this important tool. First, identify all the video, audio, and image sources (computing, DVD, CD-ROM textbooks, videotape, etc.) before designing the classroom. For example, instead of a closed-circuit TV in the classroom (adding more cost and maintenance issues), you might simply add a TV tuner as an input for the projector to enable school administrators to communicate directly with classrooms.

Classroom design should also reflect the fact that projector technology should create a 360-degree experience for teaching, learning, interacting, and sharing. The projector has multiple purposes depending on how it is used. Location of the screen is a critical consideration.

Another important consideration in successful classroom technology lies in ensuring the comfort each teacher has with the technology. Teachers need to move freely in the classroom to engage their students. A PC with a wired keyboard and/or mouse inhibits that freewheeling interactivity with students. A better scenario is enabling the teacher to move around the classroom while using the projector as a teaching tool. To achieve this, many schools use wireless mice and keyboards (or even wireless touchpads) to connect to the projector/PCs. This enables the teacher to walk from desk to desk and not scamper back to her own monitor and keyboard.

Of course, a projector is only as effective as the information it presents. It’s essential to ensure that computer and projector usage is curriculum-driven. Fortunately, in most cases, these tools combined with thoughtful planning unlock entirely new ways to present material and educate students in compelling and imaginative ways. For example, if a teacher wants to help students learn more about the behavior of the cheetah, he or she can develop a slide presentation and use clip art of the cheetah. Then, videos or movie clips can be used to educate the class about the behavior and environment of the cheetah. The teacher can then supplement that with Web searches to explore more detailed information. At review time, he or she can use the projector for real-time assessments and lead review discussions that address knowledge gaps. This richness creates a far better educational experience for the students.

International Data Corporation’s research on classroom integration confirms that projection systems dramatically affect student performance. IDC reports that 98 percent of educators believe that projectors improve student attention. What’s more, 90 percent believe projectors improve the understanding of information and 80 percent feel it improves retention as well.

PROJECTION 101 – UNDERSTANDING PROJECTOR TECHNOLOGIES

Most schools and systems today choose from two distinct projection imaging technologies –DLP® and LCD. Before we can truly understand the benefits of these alternatives, it’s important to understand how each technology works to deliver an image on the screen. Each system uses a light source, light path, color generation, imager, and a cooling fan.

DLP: Sealed Optical Engine, Filter-Free Design, High Contrast Ratio,

The light path represents the optical path that is laid out to generate an image. For DLP projectors, the light path is simple. Light travels through the RGB color filter (color generation) and the DLP chip (imager) to generate the image. The color filter sources each color component of the image synchronously with the DLP chip. The multi-color image results when each different color and image gets integrated by the eye.

The DLP chip generates the image using millions of microscopic mirrors that either reflect or diffract light. Hence, each pixel on the screen is an individual mirror on the chip itself. For a resolution of 1024x768 (XGA) you will have a total of more than 780,000 mirrors. Since the light path is fairly simple, DLP provides excellent contrast ratios, which translate into good readability.

Of course, the light source emits a significant amount of heat throughout the light path. Two components must be cooled down to keep the system thermally stable: the light source and the DLP chip. The DLP chip is typically cooled down using a heat sink on the back of the chip. Given this design, the optical system can be completely enclosed because there is no requirement to cool down the light path except for the DLP chip (except for the heat sink). There is no way for dust to reach the key optical components.

LCD Technology: Open Optical Engine, Lower Contrast Ratios

Unlike DLP systems, LCD projectors split the light path into three beams to pass through three LCD panels (red, green, and blue) that generate the image. A prism is responsible for integrating each individual color and generating the multi-color image. Since each panel is responsible for generating an image, light and heat pass through organic panels. The optical path for LCD projectors is more complex, which reduces the contrast ratio to approximately 400:1, while DLP supports contrast ratios starting at 1,000:1

Like DLP, a fan is required to cool the system. However, with LCD technology, all three panels must be cooled and the using a fan is the only way is to pass air across the panels. There is no way to isolate (or seal) the optical engine. As a result of this open optical design, filters are required to prohibit dust from entering the optical system.

AFFORDABILITY: ASSESS THE TOTAL COST OF OWNERSHIP (TCO)

When it comes to analyzing the financial aspects of a purchasing decision for projectors, it’s essential to examine the total cost of ownership that involves not only the acquisition (purchase) price but also the cost of ongoing maintenance (and replacement of prematurely failed parts and hardware units).

The initial upfront purchase prices for DLP and LCD projectors (for hardware and installation) are roughly equivalent – approximately US$700 for each. The large difference is found in maintenance. Since LCD projectors are open-image systems that use airflow to stay cool, they contain special dust filters that must be cleaned regularly (typically for every 100-200 hours of use) to stay within warranty and prevent potential downtime. That also means undesirable challenges.

For example, ceiling-mounted LCD projectors may require two people to use a ladder to clean the filter (one to climb the ladder and the other to ensure the ladder remains steady) or the unit may have to be unmounted to access the filter. There are typically 40 school weeks a year. If the LCD projector is used five hours a day, five days a week, that’s 25 hours. The filter has to be cleaned every 4 weeks, or 10 times a school year. At an average cost of $25 per cleaning, that’s $250 per year. Over the five-year expected life of the LCD projector, the cost to clean the dust filter is $1,250 per projector – far more than the cost to purchase a new one. If the school has 100 projectors, over the course of five years, it could spend $125,000 simply cleaning dust filters. If LCD filter maintenance is not followed, components such as lamps can fail prematurely.

By contrast, DLP projector components are sealed, so there is no dust filter to clean or replace. This creates a tremendous TCO advantage for DLP projectors.

RELIABILITY: COLOR DECAY AND DUSTY CONDITIONS

For both LCD and DLP projectors, long-term color reliability is an issue that must be considered in purchase decisions. Color decay occurs when the projector loses its color integrity with use over time. Intertek Group plc, an independent leader in product testing, inspection and certification, recently analyzed the reliability of DLP and LCD projectors. It found that LCD projectors suffer color and contrast degradation over time – typically manifesting itself in images on the screen that appear yellow and weaker contrasts that can appear in as little as 300 hours, necessitating a replacement of key components that can cost between $400-800. This deterioration was found in every usage model tested. However, DLP projectors offer greater reliability, producing high-quality images well beyond 4,000 hours of usage.

Reliability is also a concern in dusty environments. Dust can reduce the contrast by 50 percent – which means an LCD projector’s 500:1 ratio drops to 250:1, making it unsuitable for a classroom environment. (For more information, see www.dlp.com/reliability and www.dlp.com/dust.)

IMAGE QUALITY: ENSURING CLARITY FOR THE LONG TERM

In a classroom setting, a clear, high-quality image is a non-negotiable requirement. In many instances, teachers are displaying documents that students must read. Fuzzy images would only defeat the objectives of the lesson. There are three factors that determine the quality of a projected image:

Fill Factor – This is the term we use to measure the usable space between each pixel in the image. When the gap is wide, the result on screen is called the “screen-door effect” where the image includes a grid of horizontal and vertical lines making it appear as if you are viewing the image through a screen door. In LCD projectors, the fill factor is typically 50-60 percent. However most DLP systems offer a fill factor of more than 90 percent, creating a clearer, sharper, more lifelike image that is easily viewable from the back of the classroom.
Contrast Ratio – This is defined as the difference between the white and black parts of the picture. In LCD projectors, contrast ratios are typically 500:1 to 800:1. With the simpler, reflective optics of DLP systems, that ratio is typically between 1,000:1 to 2,000:1. The high native contrast of DLP technology makes text (from presentation and word processing programs, for example) sharper, clearer and brighter.
Motion-Video Performance – Switching speed is a technical measurement that defines the speed at which an imaging technology can operate in the effort to produce video content. The goal is to have the fastest switching speed possible to create a smoother, sharper video display due to fast switching speeds. The switching speed of LCD projectors is measured in milliseconds but the switching speed of DLP projectors is measured in microseconds. (One microsecond is 1,000 times faster than one millisecond.) This creates a clear advantage for DLP technology which is 1,000 times faster at responding to video input. The result is a clear, sharp image in video content without all of the motion blur often seen on LCD counterparts.

DLP TECHNOLOGY AT PLANO, TEXAS (USA) INDEPENDENT SCHOOL DISTRICT

Plano (Texas) Independent School District, a pre-K-12 school system of 68 school sites serves more than 53,000 students across 100 square miles in the United States. The district’s challenge: implement display technology that strengthens the curriculum while reducing costs, minimizing maintenance issues, and improving display quality.

“Although we had dozens of basic LCD projectors, we were dissatisfied with the performance we’d seen,” said Jim Hirsch, associate superintendent for academic and technology services. “The brightness on those systems lasted for about a year – at most. They yellowed and dimmed, even when we replaced bulbs.”

Plano ISD deployed 1,800 fixed-mount PLUS U2 and U5 model DLP projectors that display on 84-inch screens, providing clarity and visibility from anywhere in the classroom. The implementation lowered overall costs to Plano ISD, improved display clarity, increased reliability, simplified the user experience for faculty and students, and enhanced learning in the classroom . DLP technology is estimated to save the district $700-$1,000 per projector over the life of the devices.

“Consistent feedback that keeps coming back to us from teachers has been a variation of ‘This is the best piece of technology that has been provided to me in all my years of teaching.’ Our students echo that sentiment in surveys we’ve done by suggesting that the DLP projection systems have created a more engaging classroom for them to learn in.”

For More Information contact:

Ganesh S

Business Development Manager
DLP® Products

Texas Instruments India Ltd
Bagmane Tech Park, No 66/3
Adjacent to LRDE, Byrasandra
C V Raman Nagar
Bangalore 560 093
India

Ph : +91-80-2509 9313

Juan Alvarez

World-wide DLP® education business development manager,
Front Projection Unit,
Texas Instruments Inc
Dallas, Texas
USA

Bio-data of contributors:

Ganesh S

Currently responsible for Business Development for DLP® Products in Texas Instruments in the India market. (Which include Cinema Projectors, Front Projectors and Rear Projection TVs)

Joined Texas Instruments in 1995 in the engineering division.

Worked for Texas Instruments in the following Businesses:

Corporate Venture Projects - Engineering
DSP Applications - Engineering
DLP® Products – Engineering Management
DLP® Products – Business Development

Graduated from College of Engineering, Guindy in 1994. (With Bachelors in Electronics and Communications Engineering)

Juan Alvarez

Juan Alvarez is the DLP® education business development manger for front projection, Texas Instruments. In this capacity, he is responsible for strategic product definition and positioning, new customer design engagements, product and business development and customer support for DLP® products.

At TI, he has 8 years of experience in analog, RF, ASIC, and microcontrollers. This included marketing design-in activity in automotive, industrial, medical, and consumer products.

He holds a Bachelor in Production Engineering from Universidad EAFIT (Medellin - Colombia) and a MBA from Southern Methodist University (Dallas -- Texas).

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