## 1 Introduction  
Various types of mobile consumer-electronic devices based on a touch screen panel (TSP), for instance a navigation, a smart phone and a tablet personal computer (PC), have been spread out widely. In interacting with mobile consumer-electronic devices, visual information is the most important factor because human eye is one of the most highly developed organs and its actions are well documented. Hence, it is important to transfer a large amount of visual information to a user for immersive interaction with consumer electronics. While visual information is the most dominant sensory input for perceiving an object, haptic information coupled with visual information is also important factor for intuitive and immersive interaction between human and consumer electronic devices. The reason is that touch-based interaction is the first and most natural way and it allows a user to non-verbally and cognitively interact with devices [1]. Haptic feeling consists of kinesthetic sensation (sensory data obtained by receptors in joints, muscles and ligaments) and tactile sensation (sensory information acquired by pressure receptors in the skin). Many kinesthetic actuators are too bulky to be inserted into mobile consumer electronic devices. Therefore, for creating haptic feeling in small-sized mobile consumer electronic devices, many vibrotactile actuators, which can be easily fabricated in small size, have been developed [2; 3; 4; 5] and some of them were successfully commercialized [6; 7]. [PERSON] et al. developed an impact type of vibrotactile actuator which has wide operating frequency range for mobile applications [2]. [PERSON] et al. presented a thin vibrotactile actuator by applying adhesive electrodes onto the both side of thin piezoceramic film [3]. [PERSON] et al. suggested a flexible and wearable haptic module based on magnetically actuated motor for localized haptic and tactile feedback [4]. [PERSON] et al. presented a soft vibrotactile actuator based on an electroactive polyvinyl chloride (PVC) gel [5]. Based on these actuators, many tactile rendering methods how to generate abundant haptic sensation have been suggested. [PERSON] et al. suggested a method how to construct a vibrotactile display system using vibrotactile actuators [8]. [PERSON] et al. developed a mobile platform and a method for multimodal communication between users [9]. [PERSON] et al. addressed a gesture-haptic interaction method using an accelerometer and a vibration motor [10]. [PERSON] et al. developed a hardware platform with the ability to convert the sensed motion into vibrotactile output during scrolling task [11; 12]. [PERSON] et al. developed a mobile platform to generate clattering sensation during shaking using a solenoid-based vibrotactile actuator [13]. [PERSON] and [PERSON] found out that the duration of a control signal for generating vibration should be between 50 and 200 m sec [14]. These tactile actuators and tactile rendering methods stimulate human mechanoreceptors in skin to create vibrotactile sensation. In glabrous skin, there are four major mechanoreceptors (Meissner corpuscle, [PERSON]'s disk, Ruffini ending and Pacinian corpuscle) [15]. [PERSON]'s disk responds to quasi-static deformations of the skin, such as force or displacement in the frequency ranging from 0.4 Hz to 3 Hz. It plays an important role in detecting spatial structures in static contact, such as an edge or a bar. Ruffini ending produces a buzz-like sensation in the frequency ranging between 100 to 500 Hz. Meissner corpuscle with a frequency ranging from 2 Hz to 40 Hz, detects the dynamic deformations of the skin such as the sensation of flutter. Pacinian corpuscle, which has a frequency response in the range of 40 Hz to 500 Hz, is the most sensitive to vibration amplitude and is particularly known to serve as the detector of acceleration or vibration. Currently, consumer electronic devices provide many virtual objects having complex shape or heterogeneous surface. Currently, many virtual objects have been used in consumer electronic devices.