In the field of medical care, agriculture, environment, and so on, there are used spectral sensors in order for performing diagnostics and inspection of an object. For example, in the field of medical care, there are used pulse oximeters for measuring the blood oxygen saturation level using light absorption by hemoglobin. Further, in the field of agriculture, there are used Brix meters for measuring the sugar content of fruits using light absorption by sugar.
In the patent document 1 described below, there is disclosed a spectral image sensor for limiting the incident angle with an optical fiber for optically connecting an interference filter and a photoelectric conversion element to each other to thereby limit the transparent wavelength band to the photoelectric conversion element.
Incidentally, the spectral sensor in the related art is difficult to miniaturize. In order for manufacturing a small-sized spectral sensor, it is required to form a minute tilt structure. Further, although the minute tilt structure is often required in the spectral filter used for a high performance optical device, it is difficult to manufacture the minute tilt structure.
Further, if the minute tilt structure can be manufactured, it is possible to use the minute tilt structure for various purposes besides the spectral sensor.
In the related art technology, the minute tilt structure is manufactured using a metal mold. However, if the minute tilt structure is manufactured using the metal mold, there arise the following problems. (1) Since it costs a large amount of money to manufacture a metal mold, large initial investment becomes necessary, and the manufacturing cost of the tilt structure increases. (2) Since the metal mold is worn away with the repeated use of the metal mold, regular replacement by purchase becomes necessary, and running cost increases. (3) Since it is necessary to newly manufacture the metal mold also in the case of a minor change in geometry of the tilt structure, not only increase in cost but also a long period of time for manufacturing the metal mold becomes necessary. (4) As a feature of the metal mold, the material of the tilt structure is limited to the material (e.g., resin), which can be molded by the metal mold. (5) Since the limitation of miniaturization of the metal mold corresponds to the limitation of miniaturization of the tilt structure, it is difficult to manufacture a minute tilt structure. (6) Since a highly accurate bonding technology or the like is required in the case in which it is attempted to integrate the tilt structure and a semiconductor element, integration with the semiconductor element is difficult.