Recently, digital still cameras and digital video cameras (hereinafter, referred to as digital cameras) having high image quality have been widely used. In addition, developments for decreasing the size and the thickness of the digital camera have been made, and miniaturized digital cameras having high image quality have been built in mobile phone terminals and the like. An image pickup apparatus that is represented by a digital camera that includes an imaging device, an imaging optical system (lens optical system), an image processor, a buffer memory, a flash memory (card-type memory), an image monitor, and electronic circuits, mechanical mechanisms, and the like that control the above-described components. As the imaging devices, commonly, solid electronic devices such as CMOS (Complementary Metal Oxide Semiconductor) sensors and CCD (Charge Coupled Device) sensors are used. A photoelectric conversion process is performed for the light amount distribution imaged on the imaging device, and the acquired electrical signal is processed by the image processor and the buffer memory. As the image processor, a DSP (Digital Signal Processor) or the like is used. In addition, as the buffer memory, a DRAM (Dynamic Random Access Memory) or the like is used. The imaged image is recorded and stored in the card-type flash memory or the like, and the recorded and stored images can be displayed on a monitor.
The optical system that images an image on the imaging device is commonly configured by several aspheric lenses so as to eliminate aberration. In addition, in a case where an optical zoom function is included, a driving mechanism (actuator) that changes the focal length of a combined lens or spacing between the lens and the imaging device is needed.
In response to a request for implementing high image-quality and high functionality of the image pickup apparatus, the number of pixels of the imaging device is increased, and the resolution of the imaging device is raised. The aberration of the imaging optical system is lowered, and the resolution of the imaging optical system is raised. In addition, high functionality such as a zoom function, an auto-focus function, a hand-shake correcting function, and the like of the imaging optical system has advanced. Accordingly, the size of the image pickup apparatus is increased, and there is a problem in that it is difficult to decrease the size and the thickness thereof.
In order to solve such problems, an image pickup apparatus that is decreased in the size and the thickness by employing a compound eye structure in the imaging optical system or combining a non-solid lens such as a liquid crystal lens or a liquid lens is proposed. For example, an imaging lens device that is configured by a solid lens array disposed in a planar shape, a liquid crystal lens array, and one imaging device is proposed (for example, Patent Document 1). As shown in FIG. 38, the imaging lens device is configured by: a lens system that has a lens array 2001 having a fixed focal length; a variable focus-type liquid crystal lens array 2002 corresponding to the number of the lens array 2001; and a single imaging device 2003 that picks up an optical image that is imaged through this lens system. By employing such a configuration, images corresponding to the number of the lens arrays 2001 are imaged on the single imaging device 2003 in a divisional manner. Image processing is performed for a plurality of images acquired by the imaging device 2003 by using a calculation device 2004, and accordingly, the entire image is reconfigured. In addition, focus information is detected from the calculation device 2004, and auto-focus is performed by driving the liquid crystal lenses of the liquid crystal lens array 2002 through a liquid crystal driving device 2005. As described above, according to the imaging lens device of Patent Document 1, by combining a liquid crystal lens and a solid lens, the auto-focus function and the zoom function are implemented. In addition, the miniaturization of the above-described imaging lens device can be implemented.
In addition, there is an image pickup apparatus that is configured by one non-solid lens (a liquid lens or a liquid crystal lens), a solid lens array, and one imaging device (for example, Patent Document 2). As shown in FIG. 39, the image pickup apparatus is configured by a liquid crystal lens 2131, a compound-eye optical system 2120, an image synthesizer 2115, and a driving voltage calculating unit 2142. Similarly to Patent Document 1, the above-described image pickup apparatus forms images corresponding to the number of the lens arrays on a single imaging device 2105 and reconfigures an image through image processing. As described above, according to the image pickup apparatus of Patent Document 2, by combining one non-solid lens (a liquid lens or a liquid crystal lens array) and a solid lens array, a focus adjusting function can be implemented as a miniaturized apparatus of the thin type.
In addition, in a thin-type camera that is configured by a detector array as an imaging device and an imaging lens array and has a resolution of sub pixels, a method of increasing the resolution of the composed image by changing the relative positional deviation of two images on sub cameras has been known (for example, Patent Document 3). According to this method, a diaphragm is disposed in one sub camera, and light corresponding to half a pixel is blocked by this diaphragm. Accordingly, a problem in that the resolution cannot be enhanced in accordance with the subject distance is solved. In addition, according to Patent Document 3, a liquid lens capable of controlling a focal length by applying a voltage from the outside thereof is combined, and the imaging position of an image and the phase of a pixel are simultaneously changed by changing the focal length, whereby the resolution of the composed image is increased. As described above, according to the thin-type camera of Patent Document 3, high resolution of the composed image is implemented by combining an imaging lens array and an imaging device having a light shielding mechanism. In addition, by combining a liquid lens with the imaging lens array and the imaging device, high resolution of the composed image can be implemented.    Patent Document 1: Japanese Unexamined Patent Publication, First Publication No. 2006-251613    Patent Document 2: Japanese Unexamined Patent Publication, First Publication No. 2006-217131    Patent Document 3: PCT Japanese Translation Patent Publication No. 2007-520166
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