KR20100079452A - Image sensor - Google Patents

Abstract

PURPOSE: An image sensor is provided to projects incident to a plurality of pixels by using one micro lens. CONSTITUTION: A diffraction layer(300) diffracts a white light which is condensed by a micro lens according to the wavelength of each color. The diffraction layer comprises diffracting unit with a plurality of slits. A pixel layer(100) comprises a plurality of R, G, B pixels. The R, G, B pixels are arranged in a radical shape. A passivation layer(400) is interposed between the micro lens and the diffraction layer. A metal - IMD(Intermetal Dielectric) layer is interposed between the diffraction layer and the pixel layer.

Description

Image Sensor {IMAGE SENSOR}

Embodiments relate to an image sensor.

Complementary Metal Oxide Silicon (CMOS) Image Sensors (CIS) are semiconductor devices that convert an optical image into an electrical signal.

Incident light in the CMOS image sensor is received by the photodiode of the pixel through the color filter array. Here, a condensing technology that changes the path of light incident to a region other than the light sensing portion and collects it into the light sensing portion in order to increase the light sensitivity of the photodiode has emerged, and such a technique is a microlens forming technique.

Accordingly, the conventional CMOS image sensor is configured to form a microlens to increase the light sensitivity of the image sensor on top of the color filter array, which includes three color filters, a red filter, a green filter, and a blue filter. .

However, in order to reproduce a high resolution image, the number of pixels must be large, and as the resolution becomes higher, the size of the pixels gradually decreases.

Accordingly, the size of the microlens corresponding to the miniaturized pixel should also be reduced, but there are technical limitations in miniaturizing the microlens. In addition, when the size of the microlenses is reduced, lens spherical aberration occurs, which causes a problem in that light collection efficiency is lowered.

The embodiment provides an image sensor capable of providing incident light to a plurality of pixels using one micro lens.

An image sensor according to the embodiment includes a micro lens; A diffraction layer diffracting the white light collected through the micro lens for each color according to the wavelength; It includes a pixel layer having a plurality of pixels for receiving each color signal diffracted in the diffraction layer.

According to the image sensor of the embodiment, it is possible to provide incident light to a plurality of pixels using one micro lens.

Hereinafter, an image sensor according to an embodiment will be described in detail with reference to the accompanying drawings. However, in describing the embodiments, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In addition, in describing the embodiments, each layer (film), region, pattern, or structure may be “on” or “under” a substrate, each layer (film), region, pad, or pattern. In the case of being described as being formed "in," "on" and "under" include both "directly" or "indirectly" formed. . Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

1 is a structural diagram of an image sensor of an embodiment.

As shown in FIG. 1, the image sensor of the present embodiment includes a microlens 500 for collecting incident light, a passivation layer 400 for protecting the device, and white light transmitted through the passivation layer. Accordingly, a diffraction layer 300 diffracted for each color, a metal-IMD (Intermetal Dielectric) layer 200, and a plurality of pixel layers 100 receiving the color signals diffracted by the diffraction layer 300 are included.

The incident light of the microlens 500 is condensed into white light in which various color signals are mixed.

The diffraction layer 300 diffracts the white light collected through the microlens 500 for each wavelength. The various color signals included in the white light have their own wavelengths, and the white light diffracted by the diffraction layer 300 is collected for each color. Here, the white light condensed by the microlens 500 is vertically transmitted to the diffraction layer 300, so that white light is condensed in the central region passing vertically through the diffraction layer 300, and the white light is focused on the wavelength of each color signal. Accordingly, each color signal spectroscopically may be focused radially.

As the diffraction layer 300, a diffraction bal of a plurality of thin slits is arranged. When white light is incident on the diffraction grating, light diffracted at various angles comes out of the diffraction grating portion where no line is drawn.

The pixel layer 100 includes a plurality of R (Red) pixels, G (Green) pixels, and B (Blue) pixels in the condensing region of the color signal spectroscopically detected through the diffraction layer 300 to receive the corresponding color signal.

2 is a graph showing the diffraction angle of each signal.

White light is transmitted through the center of the color signal diffracted by the diffraction layer 300, and the diffraction angle is widened in inverse proportion to the length of the other color signals.

Among the color signals, the wavelength of the R (Red) signal is the longest, the wavelength of the G (Green) signal is the middle band, and the B (Blue) signal has the shortest wavelength. Therefore, the diffraction angle r of the R signal, the diffraction angle g of the G signal, and the diffraction angle b of the B signal among the color signals reaching the diffraction layer 300 have a relationship of r <g <b.

Accordingly, the color signal collected by the microlens 500 and passed through the diffraction layer 300 has a radial spectrum, and white light passing vertically through the diffraction layer 300 is positioned at the center of the radial spectrum. The R signal having a long wavelength centered on white light is condensed in the lens center region with a small diffraction angle. The B signal having a short wavelength is diffracted at the largest angle and condensed at the outer region of the lens, and the G signal having an intermediate wavelength between the R signal and the B signal is condensed at the middle region of the R signal and the B signal.

The pixel layer 100 arranges R pixels in the center region, B pixels in the outermost region, and G pixels in the middle region based on the radial spectrum of the color signal. In the light condensing region of the white light, a power line or other circuit configuration may be located.

In addition, by adjusting the diffraction angle by adjusting the interval of the diffraction bal, it is possible to control the condensing region of the RGB signal. Therefore, it is also possible to adjust the position of the pixel by adjusting the spacing of the diffraction shots.

As described above, the image sensor according to the embodiment uses the diffraction layer 300 to condense RGB color signals to a plurality of pixels with one microlens 500.

3 is a plan view of an image sensor of an embodiment.

The image sensor of the exemplary embodiment may condense the RGB color signals radially according to each color using one micro lens 500 and the diffraction layer 300. Accordingly, in order to receive the R signal, the G signal, and the B signal collected by the microlens 500, a pixel layer 100 including a plurality of R pixels, G pixels, and B pixels is allocated to one micro lens 500. Can be.

Therefore, even a small amount of micro lenses can control a large amount of pixels. In addition, even if the size of the pixel is miniaturized, the microlens does not need to be miniaturized, and the position of the pixel can also be adjusted by controlling the RGB signal condensing area by adjusting the thickness of the diffraction grating, thereby ensuring the condensing efficiency of the microlens even in the miniaturized pixel. can do.

Although described above with reference to the embodiment is only an example and is not intended to limit the invention, those of ordinary skill in the art to which the present invention does not exemplify the above within the scope not departing from the essential characteristics of this embodiment It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a structural diagram of an image sensor of an embodiment;

2 is a graph showing diffraction angles of RGB color signals received by the image sensor of the embodiment;

3 is a plan view of an image sensor of an embodiment;

Claims (7)

A micro lens; A diffraction layer diffracting the white light collected through the micro lens for each color according to the wavelength; And a pixel layer having a plurality of pixels for receiving each color signal diffracted in the diffraction layer. The method of claim 1, The diffraction layer, A diffraction beam including a plurality of slits to diffract the R, G, and B signals included in the white light at a diffraction angle having a magnitude inversely proportional to the length of the wavelength to radially condense the R, G, and B signals. Image sensor comprising a. The method of claim 2, The diffraction layer is an image sensor that adjusts the light condensing region of the R signal, G signal, B signal according to the size of the slit. The method of claim 1, The pixel layer, A plurality of R pixels arranged in the center area; A plurality of G pixels arranged in an outer region of the R pixel; Including a plurality of B pixels arranged in the outer region of the G pixels, The R pixels, G pixels, B pixels are radially arranged image sensor. The method of claim 1, The pixel layer, An image sensor comprising a power line in the center of the white light passing through the diffraction layer is concentrated. The method of claim 1, And a passivation layer interposed between the microlens and the diffraction layer. The method of claim 1, And an intermetal dielectric (IMD) layer interposed between the diffraction layer and the pixel layer.

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