## 1 Introduction  
With the advancement of the display industry in recent years, a wide variety of new materials are being developed for use in microtechnology and nanotechnology in display panels. A great deal of research on the internal wiring of transparent displays is being performed to increase screen scale and improve visibility [1]. Specifically, research on transparent electrodes and flexible substrates is showing active progress [2]. Since transparent materials with high optical transmittance generally tend to have low electrical conductivity in the internal wiring of the display, extensive research on anisotropic materials whose optical transmittance and electrical conductivity vary with crystal orientation is being conducted [3]. Therefore, accurate information on the thermophysical properties of transparent materials is necessary for the production of an efficient and flexible display and display panel. However, not only is the thermophysical information insufficient, but existing measurement methods cannot often be applied due to the characteristics of transparent materials [4]. The measurement of thermophysical properties is primarily conducted via analysis of the temperature change of the material using a heat input. The measurement of thermophysical properties can be categorized as either contact or non-contact according to the heat input and temperature measurement methods. The applications and limitations of contact and non-contact thermophysical measurement technologies are summarized in Table 1 below [5; 6; 7; 8; 9; 10; 11; 12; 13; 14]. The contact method inputs heat and measures temperature via direct contact with the materials, resulting in a relatively large error due to the contact resistance. Furthermore, in cases where devices and materials requiring airtightness are used as measurement targets, it is difficult to attach a sensor. Particularly, materials with low electrical conductivity may yield inaccurate measurements for the DC (Direct Current) heating method or be damaged during the measurement process. In contrast, non-contact methods have the advantages of low contact resistance, easy sensor attachment, and low material damage compared to the contact methods. Research on various non-contact methods has been conducted to explore such advantages. Among these methods, a thermophysical property measurement scheme using the photothermal effect is the most advanced, with measurement reliability demonstrated by the studies of [PERSON] [15], [PERSON] [16], [PERSON] [17], [PERSON] [18; 19], and [PERSON] [20; 21]. This scheme using the photothermal effect consists of a pump beam for the heat input and a probe beam for the temperature change measurement. It is subdivided into a displacement method, a mirage deflection method, and a collinear method according to the characteristics of the target materials and the alignment states of the pump beam and the probe beam, as shown in Figure 1.  
The photothermal displacement method was established by [PERSON] et al. [22] with one-dimensional and three-dimensional theoretical analyses for surface temperature and thermoelastic deformation conducted by [PERSON] [23; 24] and [PERSON] [25] et al. A thermal diffusion coefficient was experimentally measured by [PERSON] [22] and [PERSON] [23]. Photothermal mirage deflection is a measurement method for mono-layer isotropic materials, established by [PERSON] et al. [15]. Measurement of thermophysical properties for mono-layer anisotropic materials was conducted by [PERSON] et al. [26; 27]. For the photothermal collinear deflection method, research on materials with mono-layer/multi-layer structures was conducted by [PERSON] [28; 29], [PERSON] [16; 30], and [PERSON] et al. [31]. The photothermal effect is used to measure thermophysical properties by thermoelastically deforming a specimen via periodically modulated heating, changing the refractive index of an air layer or that of the