Introduction of TP principle and OCA on smartphone

[1] Touch screen type

1, vector pressure sensing technology touch screen: has exited the historical stage.

2, infrared technology touch screen: the price is low, but its frame is fragile, easy to produce light interference, distortion in the case of the surface.

3, capacitive technology touch screen: reasonable design concept, high precision, long life, but its price is quite high, the reflection is relatively serious.

4, resistance technology touch screen: accurate positioning, light transmittance and clarity is slightly worse.

5, surface acoustic wave touch screen: solves the various defects of the previous touch screen, clear and not easily damaged, suitable for various occasions, the disadvantage is that if there are water droplets and dust on the screen surface, the touch screen will become dull or even not working.

[two] TP type

See below:

[3] Introduction to Resistive and Capacitive TP Products

Resistive TP

Capacitive TP

1, the principle of resistive TP

working principle:

When the finger touches the screen, a contact point appears in the two layers of ITO conductive layer, because one of the conductive layers is connected to the 5V uniform voltage field in the Y-axis direction, so that the voltage of the detection layer changes from zero to non-zero, and the controller detects this. After turning on, A/D conversion is performed, and the obtained voltage value is compared with 5V, the Y-axis coordinate of the touch point can be obtained, and the X-axis coordinate is obtained in the same way, which is the common basic principle of the resistance technology touch screen. .

characteristic:

1) The price is relatively low, can work in a harsh environment, and is conducive to mass production, so it is the earliest and most widely used touch screen

2) The disadvantage of the large resistive touch screen is that it can not achieve multi-point simultaneous touch, which also limits its application in high-end smartphones and game consoles.

2, the principle of capacitive screen TP

Capacitive touch screens are divided into:

Surface Capacitive Touch nnn

Projected Capacitive Touch

A, surface capacitive touch screen

working principle:

When the user touches the screen, due to the electric field of the human body, a coupling capacitor is formed between the finger and the conductor layer, and the current from the four electrodes flows to the contact, and the current intensity is proportional to the distance from the finger to the electrode, and is located after the touch screen. The position of the touch point is accurately calculated based on the ratio and strength of the current.

characteristic:

1) It can be sensed by tapping, easy to use, and the contact between the finger and the touch screen is almost no wear, the performance is stable, and the mechanical test has a long service life.

2) The drift phenomenon is serious; it is not suitable for metal cabinets; when the outside has inductance and magnetic induction, the touch screen may be out of order.

B, projected capacitive touch screen

Fundamental:

Basic principle: The touch screen adopts multiple layers of ITO layer to form a matrix distribution. The X-axis and Y-axis cross-distribution are used as the capacitance matrix. When the finger touches the screen, the touch position capacitance can be detected through the X and Y-axis scanning. The change, and then calculate the location of the finger. Based on this architecture, the projected capacitor can be multi-touch operated.

3, the difference between surface and projected capacitive screen

1) Surface capacitive screen: mature technology, can not identify multiple points, high price, strategic alliance, can do all kinds of size screen.

2) Projected capacitive screen: The technology is immature, can recognize multiple points, and is suitable for small and medium size screens.

4, projected capacitor TP structure

[four] basic composition of CTP

[5] Introduction to OCA and water gel

1, PSA is called pressure sensitive adhesive, also known as OCA optical transparent adhesive or substrateless optical adhesive. The main purpose is to be used for LCM, Cover, Touch Panel bonding, which is simply a double-sided adhesive with high light transmission. The main component of the colloidal material is Acrylic, which has the advantages of high viscosity, high light transmittance (>90%) and good weather resistance (UV resistance). It is most suitable for the application of transparent materials. In conjunction with the use of the T/P industry.

2, water glue is also known as UV glue, the use of this product in the market has long been mature, mostly used after bonding to enhance the falx and t / p adhesion to enhance the tensile force to prevent falx off due to improper handling of personnel. The early UV glue did not reach the optical grade, and the optical grade UV glue was also developed in the past two years. The new product has a light transmittance of over 99%. Another reason for the rapid development of water gel is the problem of OCA glue itself in the production and processing yield and the difficulty of heavy work of OCA glue, which has led to the rapid development of water gel.

3, OCA and water gel contrast:

4, OCA fitting principle

Although the PSA bonding process attaching method is similar to the polarizer attaching material, although the bonding equipment is different from the past, the PSA bonding is a flat-to-plane floating and then rolled by the roller, and then the bonding operation is performed. The two kinds of bonding are all adhered in a soft and hard manner. The PSA glue has a ductile bending property, so the bubble generation probability is relatively reduced. If the precision deviation problem is not considered, only the bubble problem should be paid only to the Gap. With the two parameters of pressure, it can prevent the formation of the bonding bubble.

5, the principle of water glue fitting

The coating method of water glue is actually the same as the coating principle of RTV glue. It is only after the RTV glue is applied, it can be placed and cured, and the water glue is applied. After S/G, it must be immediately combined with C/G. Make a fitting action and apply pressure evenly, so that the glue can be smoothly extended to a comprehensive GAP that avoids missing or overflowing glue and can meet the demand.

The water gel coating method currently has:

Single syringe coating

Double syringe coating

Three-cylinder coating

Multi-needle coating

6, an important factor affecting the rate of fit

• Flatness (machine stagel /cover/sense)

• Glue amount (water gel output stability / lack of glue / overflow glue)

• Pattern (water gel coating pattern)

• Speed ​​(speed of gel coat and time of glue)

• Lower pressing uniformity (water gel thickness uniformity)

• Pressing speed and pressure (speed of gel spread / GAP)

7, water gel coating method and graphics

[Five] UV ​​curing principle

1, principle

After the UV coating is irradiated by the external radiation, the photoinitiation is initiated, and free radicals or ions are generated. These radicals or ions cross-react with the pre-polymer or the unsaturated monomer to form a monomer gene. The somatic genes begin to chain reaction to form polymer solids away from the molecule, and a complete curing process ends.

2, know UV light

• Ultraviolet (UV) is invisible to the naked eye. It is a piece of electromagnetic radiation other than visible purple light. The wavelength is usually subdivided into the following segments according to their properties:

A vacuum ultraviolet (Vacuum UV), a wavelength of 10-200nmB short-wave ultraviolet (UV-C), a wavelength of 200-290 nm C ultraviolet (UV-B), a wavelength of 290-320 nmD long-wave ultraviolet (UV-A), The wavelength is 320-400 nmE visible light (Visible light), the wavelength is 400-760nm

Ultraviolet (UV) is produced in the fishing industry, and long-wave UV (UV-A) is generally used.

3, factors affecting curing

•UV (ultraviolet) light energy

• Water gel thickness

• Curing distance

• Curing speed

• The impact of the work environment

Light Fitting Connectors

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