Since 2007, the mobile phone market has been fueled by the charm of the iPhone, which has officially detonated the upsurge of mobile phones using touch screens. Optimistic that the global mobile phone market has more than 1 billion units, mobile phones have also become the main application market that the Touch Screen industry is competing for. This article describes the main needs of current users for touch screen mobile phones, and the relationship between the needs and touch technology, with a view to providing those who want to enter this field as a reference.
Table 1 shows several important items that users consider in the application requirements of touch screen mobile phones, including drop-resistant, intuitive operation interface, operation reaction speed, endurance, key feedback, reduction of misoperation / anti-hand touch, Outdoor use, multi-touch, touch resolution, handwriting input, large screen display, and light / thin. Especially for PDA mobile phone applications that emphasize business functions, the functional requirements of touch resolution and handwriting input are more emphasized.
In terms of drop resistance, it is mainly related to ITOFilm / Glass thickness, touch panel thickness, shell material and Other technical projects. Among them, shell material is the most important. The case plus a layer of acrylic or other materials with protective properties can enhance the drop resistance of the mobile phone. In the selection of ITOFilm / Glass and the thickness of the touch panel, the thicker specifications can be selected according to the product design to avoid the problem of glass being resistant to falling and easy to break. The intuitive operation interface is also one of the most important items considered by users, and the related technical items are most related to application software support. Whether the design of touchflow can meet the intuitive response of human nature is the main Design focus.
Secondly, in terms of operation reaction speed, it is mainly related to technical items such as the operating force of the touch panel, the operating frequency of the ControllerIC, application software support, and processing core computing power. Among them, the processing core computing power and application software support are the most critical. The operation force of the touch panel allows the user to feel the movement of the touch due to a light touch, and the psychological reaction speed is relatively fast.
In terms of endurance requirements, it is related to the ITO material surface treatment, the transparency of the touch panel, the operating voltage of the touch panel and IC, and the brightness of the display module. Among them, because the entire display module is still the most consumed by the display backlight Electricity, so the design of the display backlight module is the focus of improving product endurance. The demand part of the key feedback is related to the design of the IC's feedback circuit, the software's audio or visual feedback, and the design of the system's physical vibration feedback device. In terms of reducing the need for misoperation / hands-proofing, it can be improved by increasing the operating force and identifying the usage mode by application software.
Since the use time of mobile phones is mostly outdoor, there will be more technical considerations in outdoor display, mainly related to technical details such as surface treatment of ITO material, transmittance of touch panel, and brightness of overall system display module. . For the surface treatment of ITO materials, suppliers often use ITOFilm / Glass with a high degree of haze (Haze), or plate anti-glare and low reflection materials on ITOFilm / Glass. However, the treatment of these ITO materials may cause a reduction in the overall display brightness / transparency. Therefore, it is necessary to increase the transparency of the touch panel itself or enhance the overall display brightness to make the overall display of the system clearer. In addition, as the multi-touch function of the iPhone triggered a trend, users also proposed the need for multi-touch function when viewing photos / videos and using GPS data. The demand for multi-touch is related to whether ControllerIC can process multi-touch data at the same time, as well as technical projects such as application software support. The traditional resistive touch panel, due to the limitation of the way its ControllerIC defines touch coordinates, is only used to process single-point data at the same time, so it cannot provide multi-touch functions, so it is impossible to design application software that uses multi-touch. The capacitive touch panel, because the ControllerIC can recognize multi-point coordinates at the same time, has a slight upper hand in the multi-touch function. After the launch of the iPhone, resistive touch panel manufacturers have seen the user's needs and expectations for multi-touch functions, and have also successively invested in the design and development of resistive touch panels that can support multi-touch.
In terms of the resolution of touch sensing, it is mainly related to the resolution of the touch panel and the ADC design capability of the ControllerIC, especially related to the number of bits that the ADC can receive and analyze. Currently, 8-Bit or 10-Bit is mostly used. Common, but design companies with better capabilities continue to develop towards 12-Bit and above.
In terms of handwriting input requirements, it is mainly related to technical items such as touch panel resolution, ControllerIC ADC design, and support for handwriting recognition software. At present, most touch panels that can support handwriting input are mostly resistive. Due to the overall system design of the capacitive touch panel used in the iPhone, only a touch panel with a resolution of 75 dpi is used, so it cannot support the handwriting input function. For capacitive touch panel, if you need to support handwriting input function, the minimum resolution is 100dpi. And the ADC design of ControllerIC is also related to the resolution. If you use a higher bit ADC design, it also helps users Handwriting is smoother during handwriting, which is convenient for user input.
For the large-screen display demand part, to improve the accuracy of the process / machine and the narrow border design of the touch panel, to achieve the maximum movable area. Finally, for light / thin requirements, the main technical details include the thickness of ITOFilm / Glass, the thickness of the touch panel, and the design of the shell material.
The touch screen has the advantages of a friendly and intuitive operation interface, which will eventually attract users' favor for the mobile phone equipped with a touch screen. For users, replacing traditional mechanical buttons with touch screens is the main change in appearance, but the more functions that touch screens can bring and the touch experience that traditional buttons cannot provide are more consumers. expected. Judging from the technical development of touch panels, most of the current user needs are already met, and the design focus will eventually fall on the support and design considerations of the system industry for the software.
