SYSTEMS ENGINEERING PROCESS

APPLIED FOR DEVELOPING

HANDHELD PROJECTOR

Manasa.K

Reg no: CWB0912002

1. Introduction

2. Useful application

3. Operational Analysis

4. Functional Analysis

5. Feasibility Analysis

6. Need Validation

7. Concept exploration and definition

8. Advanced Development

9. Engineering Design

What is a handheld projector?

• Handheld projectors also known as pocket, Pico, mobile projectors.

• Handheld projectors can be connected with the smart phones,

laptops, iPod or iPhones, portable gaming devices, digital cameras.

• They can project digital images onto any nearby viewing surface,

such as a screen or a wall.

• These projectors are now small enough to fit within a pants pocket.

• They can produce a high-resolution picture with good brightness

and low energy consumption.

Earlier Traditional projectors used LCD which led to many problems like:

It is bulky due to the many internal components it carries, making it

slightly inconvenient for transport.

Dead Pixels they can become permanently on or permanently off.

LCD can fail fast and replacements are very expensive.

Improper convergence of three LCD panels can cause colour to be off.

Poor overall contrast ratios.

Lamp-based technology. Lamps must be replaced after 6-8,000 hours.

Lamps are costly.

To overcome these deficiencies we can use DLP (digital light processing)

technology in handheld projector. Advantages of using DLP technology are:

Better viewing angles. And No convergence issues.

Dead pixels are rare.

Good color reproduction, high contrast, image do not fade with time.

Smaller in size.

Long lasting LED illumination up to 20000 hours.

o It should be Portable

o Space saving

o Compatible

o Flexible projection screen

o High Resolution picture

o Not expensive

o Low power consumption

o It should be less than 450grams. Should be handheld.

o Built in memory

In order to meet the operational requirements the functions are allocated

to the subsystems. Handheld projector is a fully functional projection

device based on DLP technology.

Allocation of functions to the subsystems:

The optics (subsystem 1) :

Main function of optics is the projection of light. Optics consists of the

condensing lens, projecting lens, colour filter and the shaping lens. An

engineer who is specialized in optics will develop the lens that is

required for the DLP projector.

DMD(subsystem 2) :

A semiconductor engineer and optics engineer together will develop a

DMD. Image is created using small mirrors. Mirrors are in the digital

micro mirror device(DMD).Each mirror represents one or more pixels in

the projected image.

DLP board(subsystem 3):

An embedded engineer and VLSI engineer works on this board. Its consists of

a processor and memory and Function is to run operating systems like Linux,

Android or Symbian support connectivity to personal computers, and support

various audio and video applications.

Battery (subsystem 4):

Power engineers or electrical engineers will work on the lithium- ion

rechargeable battery. Function is to provide electricity. It is light in weight

and produces high density by consuming less power.

Components required for handheld projector

By considering the operational requirements and the functional analysis,

the length, breadth and the width of the projector should be such that it

should be handheld and it should not weigh more than 450 grams.

The overall cost of the handheld projector can be estimated to 250$.

Number: Subsystems Cost estimated ($) Weight (grams)

1. Optics 50$ 100

2. DMD 70$ 85

3. DLP board 100$ 180

4 Battery 30$ 85

Total - 250$ 450

If any of the subsystem exceeds the estimated cost then it has to be

compromised with the other subsystem cost.

Example if cost estimated for optics is 50$ but it is costing more 55$ then it

should be compromised in any other subsystem cost.

When the cost is increasing the performance of the handheld projector

should also increase.

Subsystem 1(optics):

Its function is projection of light.

It consists condenser lens, projection lens color wheel, shaping lens.

And cost estimated to build this subsystem is 50$ and the domain

specialist have to see that the weight of this subsystem do not exceed

100 grams.

Subsystem 2(DMD):

Its function is to switch mirror on and off.

In the on state, light from the projector bulb is reflected into the lens

making the pixel appear bright on the screen.

In the off state, the light is directed elsewhere (usually onto a heat

sink), making the pixel appear dark.

Cost estimated is 70$ and the weight of the DMD should not go beyond

85 grams. An optic and semiconductor engineer should meet this

feasibility.

Subsystem 3(DLP board):

Its function is to run operating system.

VLSI specialist should build the board small and it should not exceed

180 grams. Cost estimated is 100$ and the board should be built within

the cost.

Subsystem 4(Battery):

Function is to provide electricity to the handheld projector.

The weight of the battery should not exceed 85 grams and cost

estimated is 30$. Power engineer should look at both cost and weight

and den manufacture battery.

Validation is important and it should be carried out in the beginning. If it

is delayed the assessments becomes more difficult. So this may lead to

risk in the later stages.

Light bulbs used as a source of light to project the images. Since these light bulbs are not compatible with the handheld projector for many reasons to overcome the drawbacks of the light bulb and to get better performance and the clarity in the projected image we make use of powerful LED’s.

What are the Drawbacks of using light bulbs in handheld projector?

It is bulky in nature and because of this compatibility issues may occur while using it in the handheld projector.

It is inefficient and it is not long lasting it has to be changed every once in 6000 to 8000 hours. Replacing the light bulb every time when expired might affect the interfacing of the handheld projector.

Light bulbs emit more heat. Hence for this we may have to use a heat sink as well as cooling fans, therefore using the dual capabilities for cooling the light bulb may lead to increase in cost.

The image clarity and the colour reproduction quality are degraded, if a light bulb is used as a source of light.

Therefore in optics subsystem it is necessary to replace the light bulb by a

powerful LED in order to improve the performance of the handheld projector.

The reasons on how the LED’s helps in improving the performance are

LED’s are long lasting up to 20000 hours. Hence it is highly efficient to use it

in a handheld projector.

LED’s are very much smaller when compared to light bulbs hence

compatibility issues is very rare while designing a handheld projector using

LED’s.

We should use LED that produces more than 2000 lumens in order to get a

better image quality that has to be projected.

The best part of LED’s are they also come along with a heat sink in order to

keep the LED cool when it is over heated. Therefore this makes it highly

efficient and long lasting.

The Cost of LED’s along with the heat sink is slightly less cheaper when

compared to that of the light bulbs along with the heat sink and cooling fans.

The above modification in the subsystem 1 (optic subsystem) can help us get

better performance and efficiency in order to meet the desired response of the

system and meet the operational requirements.

It should me made sure that as the cost of developing the

handheld projector increases the risk of developing the projector

should decrease.

If the cost of using the DLP board for developing the handheld

projector increases and exceeds the predicted development cost

then an alternative or a backup of another technology that

preforms the same function as DLP board ( cheaper than DLP

board) must be identified.

The competition in the market regarding this kind of portable

projectors must be analyzed and identified in order to develop a

better handheld projector than the others in the market.

The size and dimensions of each component in the subsystem

should me made sure that it is small and compact in order to

meet user requirements such as portability.

Hence if any size and dimension exceeds the design specifications in order

to built a handheld projector then it is necessary to look back into the

design and find a solution and then after analyzing state the specification

of the components in terms of size, dimensions, weight and performance in

order to develop the handheld projector which meets the desired response

as well as the customer requirements.

Optics

(Subsystem 1)

DMD

(Subsystem 2)

DLP

(Subsystem 3)

Battery

(Subsystem 4)

LED

Condenser lens

Shaping lens

Projection lens

Reflecting

mirrors

Processor

Memory

HANDHELD PROJECTOR

Light source:

The design for LED should meet the following specifications

The operating temperature should be 0 to 40˚C

The output power of the LED should be ≥ 20µW.

No annoying flicker like from fluorescent lamps.

Solid-State, high shock and vibration resistant.

Condensing lens:

Diameter of the lens should be 10mm.

It should Offer Higher NA.

Maximum temperature withstand is 250˚C.

Shaping lens:

Beam energy distribution efficiency:>95% of the input energy.

Working distance: 250mm (adjustable with additional lens).

DMD:

In the on state, light from the projector bulb is reflected into the lens

making the pixel appear bright on the screen.

In the off state, the light is directed elsewhere (usually onto a heat

sink), making the pixel appear dark.

Optical pixel rise and fall time should be less than 1µs.

The transmission range should be 360 nm to 800nm.

DLP board:

This board consists of processor and memory. The built in processor on

the board should satisfy the following features:

AC voltage should be 100/240V.

Frequency of 50/60Hz.

Temperature should be 0-40˚C. Recommended temperature 22˚C ±5˚C.

Battery:

It’s the power source. The battery specifications should meet the following

requirements.

Maximum output current should be 2300mA.

Weight of the battery should be less than 85 grams.

The operating temperature when charging should be between 0 to 45˚C.

When discharging 20 to 60˚C.