Apple 多点触摸的秘密

从patendocs找到了apple的multi touch专利档案，

http://www.faqs.org/patents/app/20080309631

内容很长，因为经过一些分析，ctrl+F 找multiplex，结果如下

[0024]A single touch sensing panel (i.e., a pane; capable of sensing a single touch event at a time only) can be similar to panel 100. In some embodiments, a single touch sensing panel can feature simpler touch sensing circuitry. For example, it may feature a single sensing circuit 103 which is time multiplexed to the different data lines 102. In other words, the various data lines can be periodically connected to the single sensing circuit.

[0035]In a single touch sensing panel, stimulus lines can be deactivated in the manner discussed above. If multiple sensing circuits are used (e.g., one per data line), data lines can also be deactivated in the manner discussed above. If a single time multiplexed sensing circuit is used, specific data lines can be deactivated by not connecting these data lines to the single sensing circuit.

结论就是，电容屏幕是不可能有独立信道的同时多点采样的。所以5点以上的采样将会是一个响应较慢的系统，游戏性能将会降低，除非在屏幕上空分独立区域，这样或许还可以。