HMT028ATB-C

HMT028ATB-C

LCD Module User Manual

Prepared by:

Checked by:

Approved by:

Gong huimei

Date: 2022-07-27

Date:

Rev.

Descriptions

Release Date

0.1

- Preliminary Draft release

2019-05-10

0.2

-Update Electrical Characteristics

2020-07-16

0.3

-Update Optical Characteristics

2022-07-27

URL: www.topwaydisplay.com

Document

Name: HMT028ATB-C-Manual-Rev0.3

Page: 1 of 14

TOPWAY

LCD Module User Manual

HMT028ATB-C

Table of Content

1 Basic Specification ....................................................................................................................................... 3

1.1 General Specification ............................................................................................................................... 3

1.2 Block Diagram .......................................................................................................................................... 3

1.3 Terminal Function .................................................................................................................................... 4

2 Absolute Maximum Ratings ......................................................................................................................... 5

3 Electrical Characteristics ............................................................................................................................. 5

3.1 DC Characteristics ................................................................................................................................... 5

Function Specifications .............................................................................................................................. 6

4.1 Basic Operation Function Descriptions .................................................................................................... 6

4.2 Quick Start Guide ..................................................................................................................................... 7

4.3 Command Descriptions ............................................................................................................................ 7

5 Optical Characteristics ................................................................................................................................. 8

6 LCD Module Design and Handling Precautions ......................................................................................... 10

7 CTP Mounting Instructions ........................................................................................................................... 11

8 RTP Mounting Instructions ........................................................................................................................... 12

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Document Name: HMT028ATB-C-Manual-Rev0.3

Page: 2 of 14

TOPWAY

LCD Module User Manual

HMT028ATB-C

1 Basic Specification

TOPWAY HMT028ATB-C is a Smart TFT Module with 32bit MCU on board. Its graphics engine provides

numbers of outstanding features. It supports preload and pre-design display interface that simplify the

host operation and development time. Suitable for industry control, instrumentation, medical electronics,

power electric equipment applications.

1.1 General Specification

Screen Size(Diagonal) :

2.8”

Resolution :

320 x 240(RGB)

Color Depth :

65k color (16bit)

Pixel Configuration :

RGB Stripe

Display Mode :

Transmissive / Normal White

Viewing Direction :

3H (*1) (gray-scale inverse)

9H (*2)

Outline Dimension :

79.3 x 49.1 x 9.6 (max)(mm)

(see attached drawing for details)

Active Area :

57.6 x 43.2 (mm)

Backlight :

LED

Surface Treatment :

Glare Treatment

Command I/F:

UART(3.3V Logic Levels)

Project Download:

by U-Drive (with OTG cable) or by PC (*4)

Operating Temperature :

-20 ~ +70°C

Storage Temperature :

-30 ~ +80°C

Note:*1. For saturated color display content (eg. pure-red, pure-green, pure-blue, or pure-colors-combinations).

*2. For “color scales” display content.

*3. Color tone may slightly change by Temperature and Driving Condition.

*4. Seetion 1.3 for configuration.

1.2 Block Diagram

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Document Name: HMT028ATB-C-Manual-Rev0.3

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TOPWAY

LCD Module User Manual

HMT028ATB-C

1.3 Terminal Function

UART Interface Terminal (K1)

Pin No.

Pin Name

I/O

Descriptions

1~5

No connection, leave open

6,7,8

VDD

Power supply (5.0 V)

No connection, leave open

Data Input

(eg. to Host MCU’s UART TXD)

Data output (eg. to Host MCU’s UART RXD)

Request To Send (function as busy BUSY signal)

BUSY

1:Busy

0:No busy

(eg. to Host MCU IO, check before sending data or command>)

13,14,15

VSS

Ground, (0V)

16~26

No connection, leave open

Note.

*1. User data and commands transfer through this terminal.

*2. HOST using command hand shake during communication is suggested.

UART Interface Terminal (K2)

Pin No.

Pin Name

I/O

Descriptions

1,2,3

VDD

Power supply (5.0 V)

No connection, leave open

Data Input

(eg. to Host MCU’s UART TXD)

Data output

(eg. to Host M CU’s UART RXD)

Request To Send (function as busy BUSY signal)

BUSY

1:Busy

0:No busy

(eg. to Host MCU IO, check before sending data or command>)

8,9,10

VSS

Ground, (0V)

Note.

*1. User data and commands transfer through this terminal.

*2. HOST using command hand shake during communication is suggested.

USB Interface Terminal (K3)

Pin No.

Pin Name

I/O

Descriptions

VUSB

Power supply (5.0 V)

D-

I/O

USB DATA negative signal

D+

I/O

USB DATA positive signal

USB_ID, 1:Client, 0:HOST

VSS

Ground, (0V)

Note.

*1. Display files preload through this terminal.

*2. Connect to U-Drive (with OTG cable), for files transfer

*3. For U-Drive to download project: R22=27R, R23=27R, R24=NC, R25=NC.(default)

For PC direct download project: R22=NC, R23=NC, R24=27R, R25=27R.

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Document Name: HMT028ATB-C-Manual-Rev0.3

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TOPWAY

LCD Module User Manual

HMT028ATB-C

2 Absolute Maximum Ratings

Items

Symbol

Min.

Max.

Unit

Condition

Power Supply voltage

V dd

-0.3

5.5

Operating Temperature

T OP

-20

 C

No Condensation

Storage Temperature

T ST

-30

 C

No Condensation

Note:

*1. This rating applies to all parts of the module and should not be exceeded.

*2. The operating temperature only guarantees operation of the circuit. The contrast, response speed,

and the other specification related to electro-optical display quality is determined at the room temperature, T OP =25 ℃

*3. Ambient temperature when the backlight is lit (reference value)

*4. Any Stresses exceeding the Absolute Maximum Ratings may cause substantial damage to the device. Functional

operation of this device at other conditions beyond those listed in the specification is not implied and prolonged

exposure to extreme conditions may affect device reliability.

3 Electrical Characteristics

3.1 DC Characteristics

VSS=0V, V IO =3.3V, T OP =25  C

Items

Symbol

MIN.

TYP.

MAX.

Unit

Applicable

Pin/FUNC

Operating Voltage

V DD

4.8

5.0

5.2

VDD

Rx Input Hi

V RxH

0.8V IO

V IO

Rx Input Lo

V RXL

0.2 V IO

Tx Output Hi

V TXH

0.7V IO

V IO

Tx Output Lo

V TXL

0.3V IO

Operating Current

I DD

190

VDD (*1)

Note.

*1. Normal display condition

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Document Name: HMT028ATB-C-Manual-Rev0.3

Page: 5 of 14

TOPWAY

LCD Module User Manual

HMT028ATB-C

Function Specifications

4.1 Basic Operation Function Descriptions

HMT028ATB-C

Touch Panel

TML files

Picture files

ICONS files

Custom

Memories

TFT Display

HOST

VP variables

Control and Draw Engine

Display files are stored inside FLASH memory area.

They are preloaded to HMT028ATB-C for stand alone interface use.

Those files are preloaded via USB interface (U-Drive or PC download).

All the interface flow and the touch response are based on the preloaded files

VP variables memory is inside RAM area,

it provides real time access via UART by the HOST or display onto the TFT.

Custom Memories are inside FLASH memory area

It can be accessed via UART interface by the HOST.

Control and Draw Engine executes HOST commands and response respectively

It also reports the real time Touch Key number to the HOST

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Document Name: HMT028ATB-C-Manual-Rev0.3

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TOPWAY

LCD Module User Manual

HMT028ATB-C

4.2 Quick Start Guide

Install TOPWAY

Graphics Editor

Import pictures

2. design UI flow

Download to

Smart LCD

power on &

display

Connect to

host Show

real time

data

4.3 Command Descriptions

Please refer to “SMART LCD Command Manual ”

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Document Name: HMT028ATB-C-Manual-Rev0.3

Page: 7 of 14

TOPWAY

LCD Module User Manual

HMT028ATB-C

5 Optical Characteristics

Item

Symbol

Condition

Min

Typ

Max

Unit

Remark

θT

View Angles

θB

CR ≧ 10

Degree

Note 3

θL

θR

Contrast Ratio

θ = 0°

400

500

Note 4

T ON

Response Time

25 ℃

Note 5

T OFF

0.218

0.268

0.318

White

Note 1,6

0.234

0.284

0.334

0.630

Red

0.58

0.68

Note 1,6

Chromaticity

Backlight is

0.284

0.334

0.384

0.331

Green

0.281

0381

Note 1,6

0.562

0.612

0.662

0.149

Blue

0.099

0.199

Note 1,6

0.013

0.063

0.113

Uniformity

Note 1,2

NTSC

Note 1,6

Luminance

160

200

cd/ ㎡ Note 1

Note ： The parameter is slightly changed by temperature, driving voltage and materiel.

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Document Name: HMT028ATB-C-Manual-Rev0.3

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TOPWAY

LCD Module User Manual

HMT028ATB-C

Note 1:

Note 2:

The data are measured after LEDs are turned on for 5 minutes. LCM

The luminance uniformity is calculated by using following formula.

displays full white. The brightness is the average value of 9 measured

△ Bp = Bp (Min.) / Bp (Max.)×100 (%)

spots. Measurement equipment PR- 705 (Φ8mm)

Bp (Max.) = Maximum brightness in 9 measured spots

Measuring condition:

Bp (Min.) = Minimum brightness in 9 measured spots .

- Measuring surroundings: Dark room

- Measuring temperature: Ta=25 ℃ .

- Adjust operating voltage to get optimum contrast at the

center of the display.

Measured value at the center point of LCD panel after more than 5

minutes while backlight turning on.

Note 3:

Note 4:

The definition of viewing angle:

The definition of contrast ratio (Test LCM using PR-705):

Refer to the graph below marked by θ and Ф

Contrast

Luminance When LCD is at “White” state

Ratio(CR)=

Luminance When LC D is at “Black” state

(Contrast Ratio is measured in optimum common electrode

voltage)

Note 5:

Note 6:

Definition of Response time. (Test LCD using DMS501):

Definition of Color of CIE Coordinate and NTSC Ratio.

The output signals of photo detector are measured

when the input signals are changed from

Color gamut:

“black” to “white”(falling time)

Area of RGB triangle

X100%

and from “white” to “black”(ris ing time), respectively.

Area of NTSC triangle

The response time is defined as

the time interval between the 10% and 90% of amplitudes.Refer to

figure as below.

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Document Name: HMT028ATB-C-Manual-Rev0.3

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6 LCD Module Design and Handling Precautions

6. 液晶显示模块设计和使用须知

Please ensure V0, VCOM is adjustable, to enable LCD -

请注意 V0, VCOM 的设定 , 以确保液晶显示模块在不同的

module get the best contrast ratio under different

使用温度下以及在不同的视角和位置观察模块显示，均

temperatures, view angles and positions.

能达到最佳对比度，请务必将应用电路上设置为对比度

可调。

Normally display quality should be judged under the best -

请注意液晶显示模块的显示品质判定是指在正常对比度

contrast ratio within viewable area. Unexpected display

下以及视窗 (V.A) 范围内进行的，非正常对比度下液晶可

pattern may com out under abnormal contrast ratio.

能会出现非预期的显示不良，应注意区分。

Never operate the LCD module exceed the absolute -

请勿在最大额定值以外使用液晶显示模块。

maximum ratings.

Never apply signal to the LCD module without power -

请勿在没有接通电源的条件下，给液晶显示模块输送信

supply.

号。

Keep signal line as short as possible to reduce external -

请尽可能缩短信号线的连接，以避免对液晶显示模块的

noise interference.

信号干扰。

IC chip (e.g. TAB or COG) is sensitive to light. Strong light -

集成电路因 IC 芯片 ( 如 TAB 或 COG) 对紫外线极为敏感，

might cause malfunction. Light sealing structure casing is

强光环境下可能会引起液晶显示模块功能失效，故应采

recommended.

用不透光的外壳。

Make sure there is enough space (with cushion) between -

请在液晶显示模块与外壳之间保留足够的空间 ( 可使用衬

case and LCD panel, to prevent external force passed on

垫 ) ，以缓冲外力对液晶显示模块的损坏或因受力不均而

to the panel; otherwise that may cause damage to the LCD

产生的显示不匀等异常现象。

and degrade its display result.

Avoid showing a display pattern on screen for a long time -

避免液晶显示屏在某一画面下长时间点亮，否则有出现

(continuous ON segment).

残影的风险；请通过软件每隔一段时间改变一次画面。

LCD module reliability may be reduced by temperature -

液晶显示模块的可靠性可能因温度冲击而降低。

shock.

When storing and operating LCD module, avoids exposure -

请勿在阳光直射、高湿、高温或低温下储存和使用液晶

to direct sunlight, high humidity, high or low temperature.

显示模块，这将造成液晶显示模块的损坏或失效。

They may damage or degrade the LCD module.

Never leave LCD module in extreme condition (max./min -

请勿在极限环境 ( 最大 / 最小存储 / 工作温度 ) 下使用或放

storage/operate temperature) for more than 48hr.

置液晶显示模块超过 48 小时以上。

Recommend LCD module storage conditions is 0 C~40 C -

液晶显示模块建议存储条件为 : 0 C~40 C <80%RH 。

<80%RH.

LCD module should be stored in the room without acid, -

请勿让液晶显示模块存储于带有酸性 , 碱性 , 有害气体

alkali and harmful gas.

环境之中。

Avoid dropping & violent shocking during transportation, -

在运输过程中 , 请勿让液晶显示模块跌落与猛烈震动 ,

and no excessive pressure press, moisture and sunlight.

同时避免异常挤压 , 高湿度 , 与阳光照射 .

LCD module can be easily damaged by static electricity. -

液晶显示模块极易受静电损坏，请务必保证液晶显示模

Please

maintain

optimum

anti-static

working

块在防静电的工作环境中使用或保存。 ( 如 : 烙铁正确接

environment to protect the LCD module. (eg. ground the

地 , 等 )

soldering irons properly)

Be sure to ground the body when handling LCD module. -

拿取液晶显示模块时需注意操作人员的接地情况。

Only hold LCD module by its sides. Never hold LCD -

请手持液晶显示模块的边沿取放模块，防止热压纸或 TAB

module by applying force on the heat seal or TAB.

部位受力。

When soldering, control the temperature and duration -

焊接液晶模块时，请注意控制烙铁的温度、焊接时间，

avoid damaging the backlight guide or diffuser which

以免烫坏导光板或偏光片，导致显示不匀等不良现象发

might degrade the display result such as uneven display.

生。

Never let LCD module contact with corrosive liquids, which -

请勿使用洗板水等腐蚀性液体接触液晶模块，以免腐蚀

might cause damage to the backlight guide or the electric

导光板或模块电路。

circuit of LCD module.

Only clean LCD with a soft dry cloth, Isopropyl Alcohol or -

仅可使用柔软的干布 , 异丙醇或乙醇清洁液晶屏表面，

Ethyl Alcohol. Other solvents (e.g. water) may damage the

其他任何溶剂 ( 如 : 水 ) 都有可能损坏液晶模块。

LCD.

Never add force to components of LCD module. It may -

请勿挤压液晶显示模块上的元器件，以避免产生潜在的

cause invisible damage or degrade the module's reliability.

损坏或失效而影响产品可靠性。

When mounting LCD module, please make sure it is free -

装配液晶显示模块时，请务必注意避免液晶显示模块的

from twisting, warping and bending.

扭曲或变形。

Do not add excessive force on surface of LCD, which may -

请勿挤压液晶显示屏表面，这将导致显示颜色的异常。

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Document

Name: HMT028ATB-C-Manual-Rev0.3

Page: 10 of 14

cause the display color change abnormally.

LCD panel is made with glass. Any mechanical shock (e.g. -

液晶屏由玻璃制作而成，任何机械碰撞 ( 如从高处跌落 )

dropping from high place) will damage the LCD module.

均有可能损坏液晶显示模块。

Protective film is attached on LCD screen. Be careful when -

液晶屏表面带有保护膜 , 揭除保护膜时需要注意可能产

peeling off this protective film, since static electricity may

生的静电。

be generated.

Polarizer on LCD gets scratched easily. If possible, do not -

因液晶显示屏表面的偏光片极易划伤，安装完成之前请

remove LCD protective film until the last step of

尽量不要揭下保护膜。

installation.

When peeling off protective film from LCD, static charge -

请缓慢揭除保护膜，在此过程中液晶显示屏上可能会产

may cause abnormal display pattern. The symptom is

生静电线，此为正常情况，可在短时间内消失。

normal, and it will turn back to normal in a short while.

LCD panel has sharp edges, please handle with care.

请注意避免被液晶显示屏的边缘割伤。

Never attempt to disassemble or rework LCD module.

请不要试图拆卸或改造液晶显示模块。

If display panel is damaged and liquid crystal substance -

当液晶显示屏出现破裂 , 内部液晶液体可能流出 ; 相关

leaks out, be sure not to get any in your mouth, if the

液体不可吞吃 , 绝对不可接触嘴巴 , 如接触到皮肤或衣

substance comes into contact with your skin or clothes

服 , 请使用肥皂与清水彻底清洗 .

promptly wash it off using soap and water.

7 CTP Mounting Instructions

7. 电容触摸屏安装指导

7.1 Bezel Mounting (Figure 1)

7.1 面框安装（附图 1 ）

The bezel window should be bigger than the CTP active -

客户面框窗口应大于 CTP 动作区域，各边离动作区应

area. It should be≥0.5mm each side.

≥ 0.5mm.

Gasket should be installed between the bezel and the CTP -

面框与 CTP 面板间应垫有胶垫，其最终间隙约为 0.5 ～

surface.

1.0mm.

The final gap should be about 0.5~1.0mm.

It is recommended to provide an additional support -

建议必要时在背面提供附加支架 ( 例如无安装结构的薄型

bracket for backside support when necessary (e.g. slim

TFT 模块 ) ，应仅利用适当支撑以保持模块位置 .

type TFT module without mounding structure). They

should only provide appropriate support and keep the

module in place.

The mounting structure should be strong enough to -

安装结构应具有足够的强度，以防止外部不均匀力或扭

prevent external uneven force or twist act onto the

曲力作用到模块上 .

module.

Figure 1

7.2 Surface Mounting (Figure 2)

7.2 嵌入安装（附图 2 ）

As the CTP assembling on the countersink area with -

客户面框应具有使用双面胶粘贴 CTP 的结构沉台面，其

double side adhesive.

粘贴面要求平整且洁净无污以保证粘贴牢靠 .

The countersink area should be flat and clean to ensure

the double side adhesive installation result.

The Bezel is recommend to keep a ga p (≥0.3mm each -

考虑到制作误差，建议面框与 CTP 盖板之间四周留有

side) around the cover lens for tolerance.

≥ 0.3mm 间隙 .

It is recommended to provide an additional support -

建议必要时在背面提供垫有胶垫附加支架 ( 例如无安装结

bracket with gasket for backside support when necessary

构的 TFT 模块 ) ，应仅利用适当支撑以保持模块位置 .

(e.g.

TFT module without mounding structure). They

should only provide appropriate support and keep the

module in place.

The mounting structure should be strong enough to -

安装结构应具有足够的强度，以防止外部不均匀力或扭

prevent external uneven force or twist act onto the module

曲力作用到模块上。

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Figure 2

7.3 Additional Cover Lens Mounting (Figure 3)

7.3 覆加盖板（附图 3 ）

For the case of additional cover Lens mounting, it is -

需要覆加玻璃盖板的安装，为确保其功能，有必要查看

necessary to recheck with the CTP specification about the

产品规格书中有关盖板材料和厚度的说明 .

material and thickness to ensure the functionality.

It should keep a 0.2~0.3mm gap between the cover lens -

玻璃盖板与 CTP 表面之间应留有 0.2 ～ 0.3mm 间隙 .

and the CTP surface..

The cover lens window should be bigger than the active -

玻璃盖板视窗应大于 CTP 动作区域，各边离动作区应

area of the CTP.It should be≥0.5mm each side.

≥ 0.5mm 。

It is recommended to provide an additional support -

建议必要时在背面提供附加支架 ( 例如无安装结构的薄型

bracket for backside support when necessary (e.g. slim

TFT 模块 ) ，应仅利用适当支撑以保持模块位置 .

type TFT module without mounding structure). They

should only provide appropriate support and keep the

module in place.

The mounting structure should be strong enough to -

安装结构应具有足够的强度，以防止外部不均匀力或扭

prevent external uneven force or twist act onto the

曲力作用到模块上 .

module.

Figure 3

8. 电阻触摸屏安装指导

8 RTP Mounting Instructions

为避免面框直接压在动作区 (A.A.) 上造成误动作，面框与

It should bezel touching the RTP Active Area (A.A.) to

电阻触摸屏 (RTP) 之间应留有一定的空隙 D=0.2~0.3mm 之

prevent abnormal touch.It should left gab D=0.2~0.3mm

间 .( 附图 4)

in between. (Figure 4)

Outer bezel design should take care about the area

设计面框时，要注意用面框保护触摸屏四周的非保证操作

outside the A.A. Those areas contain circuit wires which is

区域，因为布线区域在此处形成一台阶，在此区域附近

having different thickness. Touching those areas could de-

操作时 ITO Film 变形较大，容易导致 ITO 损坏而降低寿

form the ITO film. As a result bezel the ITO film be

命。为保护 RTP 和避免误操作，在 RTP 与面框之间垫缓

damaged and shorten its lifetime.

冲物（ Gasket ），我们建议设计面框应覆盖动作区的边

It is suggested to protect those areas with gasket (between

缘，面框边缘到 V.A. 区的距离 B≥0.50mm; 垫圈内边缘

the bezel and RTP).The suggested figures are B≥0.50mm;

到 V.A. 区的距离 C≥0.50mm. (附图 4)

C≥0.50mm. (Figure 4 )

The bezel side wall should keep space E= 0.2 ~ 0.3mm

在设计面框与 RTP 组装时，应考虑到面框内侧与 RTP 外侧

from the RTP. (Figure 4)

的间距 E≥0.2mm. (附图 4)

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Figure 4

In general design,

通常设计时：

RTP V.A. should be bigger than the TFT V.A.

RTP 的可视区 V.A. 应不小于 TFT 的可视区 V.A.

and RTP A.A. should be bigger than the TFT A.A.

及 RTP 的动作区 A.A. 应不小于 TFT 的动作区 A.A.

(Figure 5)

( 附图 5)

Figure 5

Warranty

This product has been manufactured to our company’s specifications as a part for use in your company’s general

electronic products. It is guaranteed to perform according to delivery specifications. For any other use apart from

general electronic equipment, we cannot take responsibility if the product is used in medical devices, nuclear power

control equipment, aerospace equipment, fire and security systems, or any other applications in which there is a direct

risk to human life and where extremely high levels of reliability are required. If the product is to be used in any of the

above applications, we will need to enter into a separate product liability agreement.

We cannot accept responsibility for any defect, which may arise form additional manufacturing of the product

(including disassembly and reassembly), after product delivery.

We cannot accept responsibility for any defect, which may arise after the application of strong external force to the

product.

We cannot accept responsibility for any defect, which may arise due to the application of static electricity after the

product has passed our company’s acceptance inspection procedures.

When the product is in CCFL models, CCFL service life and brightness will vary according to the performance of the

inverter used, leaks, etc. We cannot accept responsibility for product performance, reliability, or defect, which may

arise.

We cannot accept responsibility for intellectual property of a third part, which may arise through the application of our

product to our assembly with exception to those issues relating directly to the structure or method of manufacturing of our

product.

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