LF1201 - LiteMax Electronics, Inc.

LiteMax LF1201

Sunlight Readable 12.1" LCD Display

Preliminary Product Document

Rev : 0.3

Date : Jan. 29,2000

LiteMax Electronics Inc.

No.8, Lane 89, Sec. 3, Chung-yang Rd.,

Tucheng City, Taipei County, Taiwan

R.O.C.

Tel: 886-2-2267-6766

Fax: 886-2-2267-6779

Homepage: http://www.litemax.com.tw

General Introduction

The Lite Max model LF1201 is a 12.1" sunlight readable color TFT-LCD

product. It consists of TFT LCD panel module (SP1201), LCD controller

board (LCN101) and backlight inverter (LI2001).

By applying the Lite Max of very high brightness (VHB) technical to the

LF1201, it has a big improved quality on display. Basically, there are three

major advantages for VHB application and they are described below:

1. Brightness

For a traditional LCD in the market now, the brightness are measured to be

around 200 ~ 350 nits under a regular sunny day. However, the brightness

of LF1201 can be up to 1308 nits. A better enhancement of picture quality

can be shown on the screen in the indoor or outdoor environment.

2. Viewing Angle

View Angle (degree) -80 -60 -40 -20 0 20 40 60 70

Brightness (nits) 324.2 645.5 1135 1317 1308 1059 465.7 144.3 96.91

From above measured data, the LF1201 has a wider viewing angle. It means

the viewing angle for LF1201 is closer to 180 degree than a traditional LCD

on the same brightness of viewing angle position.

3.Contrast Ratio

The definition of Contrast Ratio: ON (White) luminance / OFF (Black)

luminance.

Luminance of LCD screen in white is Y (w)

Luminance of LCD screen in black is Y (b)

In the dark ambient, the LF1201 screen in white is 1308 nits and in black is

6.69 nits. Then

Contrast Ratio: 1308/6.69=195.5

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However, the Contrast Ratio drops significantly in the bright ambient for

the real application. The reason is due to the reflections and glare at the

surface of LCD. Hence, the contrast ratio should be modified as below:

The Ambient Contrast Ratio: [Y (w)+Y (g)]/[Y (b)+Y (g)]

Where Y (g) is the background luminance Y (g) caused by light scattering

or reflection at the LCD front surface.

In the bright ambient of temperature 25 degree C and indoor, the

background luminance Y (g) of LF1201 is <= 10 nits, then

The Min of Contrast Ratio: (1308+10)/(6.69+10)= 78.97

We know the max brightness usually is under 300 nits for a traditional LCD

application. Under the same bright ambient compared with LD1201, the Min

of contrast ratio of traditional LCD will be less than 30 for a real application.

Hence, we can make a conclusion that LF1201 can perform a better quality

image.

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A. LCD Panel Module (SP1201)

1. Introduction

SP1201 is a 12.1", high efficiency sunlight readable LCD panel module. This

module consists of Sharp LQ121S1DG11 TFT color LCD and a Lite Max

very high brightness (VHB) backlight mounted onto the back of the LCD.

The entire is about 24.7 mm thick and has the same footprint as the original

Sharp LQ121S1DG11 LCD.

The SP1201 LCD is a high contrast, wide view-angle LCD and a wider

operating temperature range. In the normal mode operation, the SP1201

module delivers 1308 Cd/m² (nits) LCD screen brightness at a backlight

power of 23.25 Watts. With a dimming inverter, the module can be operated

in a reduced brightness mode with lower power consumption and longer

lamp life. In both modes, the display is highly readable under direct

sunlight. In addition, the color tone of 'white' displayed on the LCD screen

is closely matched to the color of normal sunlight.

With a wide dimming range of Lite Max inverter, the SP1201 LCD panel

module presents a surperb color image over ambient illumination levels

from full bright sunshine to total darkness, making it highly suitable for

various outdoor applications.

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2. LCD Panel Module Optical Performance

The typical SP1201 LCD panel module screen luminance and contrast ratio

are shown in the figures below:

200

400

600

800

1000

1200

1400

-80-70-60-50-40-30-20-100 1020304050607080

Viewing Angle

Brightness

Horizontal

view

Vertical

view

The LCD screen luminance is measured with the LCD in the 'Off' state (i.e.

the pixels are not energized). This is the 'White' state with maximum

luminance. Quite often, this 'Off' state is brighter than the 'White' displayed

on the screen after the LCD is turned on. The difference may be caused by

the graphics card and/or on the LCD controller card driving this display.

When the LCD is driven properly, the luminance difference between the

'Off' state and the 'White' color should be less than 10 %.

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100

150

200

250

-80-70-60-50-40-30-20-100 1020304050607080

Viewing Angle

Contrast Ratio

Vertical

view

Horizontal

view

The inherent contrast ratio (CR) of the LCD is the luminance ratio between

the 'White' and the 'Black' states measured in a dark room. In outdoor

environments, the contrast ratio of the display drops significantly due to

the surface reflections and glare caused by the ambient illumination at the

front surface of the LCD and other surfaces such as touch screen or the

protective window.

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3. Characteristics

Parameters Value Units Condition

LCD Screen Luminance 1308 Cd/m² White (LCD in off state)

Luminance Uniformity 20% or better Note 2

LCD Contrast Ratio 195.5 White vs Black

78.96(Min) with 10 nits background Y(g)

Screen Dimming Ratio 200:1 With LI2001 inverter

LCD Screen Chromaticity

White ( LCD in off state ) x=0.3430, y=0.3701 Measured at normal direction

Red x=0.5946, y=0.3518 Measured at normal direction

Green x=0.3141, y=0.5798 Measured at normal direction

Blue x=0.1550, y=0.1529 Measured at normal direction

Viewing Angle

3:00 to 9:00 direction -80 ~ 45 degrees Contrast Ration >=10

6:00 to 12:00 direction -50 ~ 45 degrees Contrast Ration >=10

3:00 to 9:00 direction -80 ~ 70 degrees Screen luminance >= 100 nits

6:00 to 12:00 direction -80 ~ 80 degrees Screen luminance >= 100nits

Backlight Power Consumption 23.25 Watts Excluding inverter losses

LCD Module Weight Grams with encasing

Number of CCFLs 8

Note 1: All data are measured at 25-º C± 2 º C ambient temperature.

Note 2: Uniformity = (Lmax – Lmin)/(Lmax – Lmin).

Lmax (Lmin) is the maximum (mininum) luminance measured with a 10 mm diameter

meter aperture over the LCD active area except the last 10 mm area from the edge.

3. Optical specification, Signal Timing Specification and Signal

Timing Wave Form

In addition to the data described on characteristic, please refer to Sharp

LQ121S1DG11 for other information.

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4. Interface connection

5.1 Electrical Interface Connection

Please refer to Sharp LQ121S1DG11.

5.2 Backlight Lamp Connections

The very high brightness (VHB) backlight in the SP1201 module uses a

total of 8 cold cathode fluorescent lamps to achieve the required luminance.

The lamps are electrically connected in two separate groups. Group 1

contains lamps #1, #2, #3, #4 and Group 2 contains lamps #5, #6, #7, #8.

The lamps are oriented in the horizontal direction with the #1 lamp at the

topside of the LCD.

The lead wires connecting the lamps are terminated with two 11-pins

connectors. The following are the connector pin out assignments.

Pin # Group 1 Connector Group 2 Connector

1NC

2NC

3 Lamp#1 Lamp#5

4NC

5 Lamp#2 Lamp#6

6NC

7 Lamp#3 Lamp#7

8NC

9 Lamp#4 Lamp#8

10 NC NC

11 Common Common

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6. Backlight Lamp Driving Specification

It is recommended to use an inverter with a 1200 to 1300 Vrms starting

voltage to run the VHB backlight in the SP1201 LCD panel module. At the

maximum LCD screen luminance, the lamp voltage and current are listed

below:

Operating Voltage 470 Vrms

Lamp Current **** mArms

At this driving condition, the backlight delivers the specified maximum LCD

screen brightness with power consumption about 23.25 Watts. Since most

inverters used to driver CCFLs have efficiency between 75 % - 80 %, the

total DC power input to the inverter is about 31 Watts. When the backlight

is dimmed down, the power consumption decreases.

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7. Mechanical Characteristics

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B. LiteMax LI2001 inverter

1. Introduction

LI2001 is a CCFL inverter to operate Lite Max very high brightness (VHB)

backlights includes the sunlight readable LCD modules. The inverter has

an on-board pulse width modulation (PWM) dimming circuit for extremely

wide range luminance adjustment. Over the entire dimming range, there is

no noticeable lamp flickering and the uniformity of the backlight is well

maintained. When using LI2001 with LiteMax sunlight readable LCD

modules, it is not necessary to synchronize the PWM circuit to vertical

sync signal of the LCD.

2. Dimming Control

The LI2001 accepts a 0-5V analog voltage for dimming control. It has a

pulse width modulation (PWM) dimming circuit for luminance adjustment.

As the dimming voltage Vd decrease from +5V, the lamp current waveform

is pulse width modulated at a repetition rate high enough to prevent LCD

flicker. Within each PWM, the lamps in the backlight are turned fully 'ON'

for a fraction of the cycle time. The human eyes, being very slow with

respect to the PWM rate, respond to the average light produced over the

PWM cycle. As a result, the luminance of the backlight and/or the LCD

screen is approximately to the duty cycle of the PWM waveform.

The lamp current waveform with the PWM circuit

Set at less than 100%

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In general, inverters with PWM dimming have a very wide luminance

adjustment range. For most practical cases, the LI2001 inverter can achieve

a dimming ratio up to 200:1. Hence, the luminance of the backlight or LCD

screen can be adjusted from 100% to 0.5%.

The 0- 5V dimming voltage can be generated simply by a potentiometer, by

a digitally controlled UP/DOWN counter or a digital potentiometer. The

inverter provides a regulated +5V supply to power the dimming circuit.

However, the maximum current drain from this source should be kept less

than 5 mA.

At a Vd input about 0.34V and less, the duty cycle of the PWM waveform is

0% and thus, the lamps are 'OFF'. In order to fully utilize the available

dimming voltage, Vd should be biased to about 0.32V and then ramping up

to 5.0V.

3. Electrical Characteristics

The LI2001 inverter operates at 12V DC input and can drive up to 8 lamps

for a maximum output power about 22 Watts. In addition, the inverter has a

regulated +5V output serving as a voltage source for the dimming control

circuit.

Electrical Characteristics

Parameters Min Typ Max Units Conditions

Input Vpltage (Vin) 11.5 12 12.5

Input current (I) 2.3 Vin=12, Vd=5 V

Lamp Starting Voltage (Vst) 1300 Vrms Vin=12, Vd=5 V

Frequency (f) 50 53 58 Khz

ON/OFF Control -OFF 0 0.2

-ON Floating

Dimming Voltage(Vd)

@ 100% Duty Cycle 4.9 5 Vdc Max brightness

@ 0% Duty Cycle 0.3 0.34 Vdc Zero brightness

5V Output (+5VOUT) 4.85 5 5.3 Vdc 11.5<Vin<12.5V

5V Output Source Current 5

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Absolute Maximum Rating

Parameters Min Max Units

Inverter Input Voltage (Vin) 11 13 Vdc

Operating Temperature Range 0 50 C

Storage Temperature Range -20 80 C

4. Interface Connector

Input Connector ( CN1)

Pin# Function

1 5V Output

2 12V Input

3 12V Input

4 Dimming Control

5 Ground

6 Ground

7 ON/OFF Control

Output Connector (CN2 & CN3)

PIN # Function

3, 5, 7, 9 Lamp Connections

11 Lamp Common

1,2,4,6,8,10 No connection

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5. Mechanical Characteristics

LiteMax Electronics Inc. reserves the right to make changes to this document and the produc

which it describes without notice. LiteMax Electronics Inc. also shall not be liable for technical

or editorial errors or omissions made herein; nor for incidental or consequential damages

resulting from the furnishing, performance, or use of this product. In addition, LiteMax

Electronics Inc. takes no responsibility for damage caused by improper use of this product whic

does not meet the conditions for use specified in this specification sheet.

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