Optical filter, camera module, and electronic device

Abstract

The present invention addresses the problem of providing an optical filter capable of achieving both color shading suppression and ghost suppression of a camera image at a high level. This optical filter fulfills requirements (a) and (b): (a) in a wavelength region of 430-580 nm, a minimum value T<b-0> of transmittance of light incident from a vertical direction, a minimum value T<b-30> of transmittance of light incident from a direction inclined at 30 degrees with respect to the vertical direction, and a minimum value T<b-60> of transmittance of light incident from a direction inclined at 60degrees with respect to the vertical direction are all 55% or more and less than 90%; and (b) in a wavelength region of 700-780 nm, a mean value OD<a-0> of optical density to the light incident from the vertical direction, a mean value OD<a-30> of optical density to the light incident from the direction inclined at 30 degrees with respect to the vertical direction, a mean value OD<a-60> of opticaldensity to the light incident from the direction inclined at 60 degrees with respect to the vertical direction are all 1.8 or more.

Description

technical field [0001] The invention relates to an optical filter, a camera module and electronic equipment. More specifically, it relates to an optical filter having specific optical characteristics, a camera module using the optical filter, and an electronic device including the camera module. Background technique [0002] In solid-state imaging devices such as video cameras, digital still cameras, and mobile phones with camera functions, charge coupled devices (CCDs) or complementary metal oxide semiconductors (CCDs) as solid-state imaging elements for color images are used. , CMOS) image sensor. These solid-state imaging devices use silicon photodiodes that are sensitive to near-infrared rays that cannot be sensed by human eyes in their light-receiving portions. In these solid-state imaging devices, it is necessary to correct the visual sensitivity to present natural colors seen by the human eye, and optical filters that selectively transmit or cut light in specific wa...

AI Technical Summary

Problems solved by technology

In Patent Document 4, broad absorption in the near-infrared wavelength region is achieved by using a compound mainly having a dithiolene structure, but the absorption intensity around 700 nm is not sufficient

In particular, when used under high incident angle conditions (for example, 45-degree incident angles) that have been accompanied by lower profile camera modules in recent years, image degradation due to color shading may occur

[0007] In addition, Patent Document 5 discloses a near-infrared cut filter having a near-infrared-absorbing glass substrate and a layer containing a near-infrared-absorbing pigment. However, even in the structure described in Patent Document 5, color shading cannot be sufficiently improved. Case

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