JPH02284469A - Color sensor - Google Patents

Abstract

PURPOSE:To introduce an incident light through one color filter into a p-i-n junction with a very little displacement and avoid the light incidence into an adjoining photodiode and improve the spectral sensitivity characteristics of a color sensor by making light transmitting conductive layers be thin films. CONSTITUTION:Lights coming from a direction R are introduced into photodiodes PD1-3 composed of p-type, i-type and n-type amorphous silicon films 20, 22 and 24 and so forth through a light transmitting substrate 10 and through color filters 12, 14 and 16 which transmit the lights having wavelengths in the respectively predetermined wavelength ranges and electric signals corresponding to the intensities of the lights in the respective ranges are generated. The signals are taken out from circuits which connect transparent conductive films 18, 28 and 40 to metal electrode films 26, 38 and 48. The thickness of the transparent conductive film is selected to be several hundreds to several thousands of angstroms. As a result, even if the lights are applied obliquely, they do not enter the adjoining photodiodes, so that the intensities of the lights in the respective ranges detected by the photodiodes PD1-3 can be measured accurately.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an optical sensor that receives light and converts it into an electrical signal, and in particular, it relates to an optical sensor that receives light and converts it into an electrical signal, and in particular, it relates to an optical sensor that receives light and converts it into an electrical signal. This invention relates to a color sensor that is used to identify the color of light.

[Prior Art] A color sensor can easily identify the color of incident light and has a wide range of uses. Color sensors can be used, for example, in video cameras' auto-white! -Used for measuring wavelength components of incident light for balance processing. Due to its usage, color sensors are often required to discriminate the color of light with characteristics close to human visibility.

Conventionally, the most commonly used color sensor utilizes photovoltaic force generated by a pn junction of single crystal silicon. However, single-crystal silicon has a problem in that the range of wavelengths of light that generates photovoltaic force (sensitivity wavelength range) is too wide. In particular, t11 crystal silicon has its peak sensitivity in the infrared wavelength region.

Therefore, a color sensor using single crystal silicon requires a filter to cut out the infrared wavelength region. As a result, the color sensor has a large volume and is expensive.

On the other hand, without using single crystal silicon, amorphous silicon PL
It is known that in the case of a color sensor using an n-junction, it is possible to easily reduce the sensitivity in the infrared wavelength region even without a filter.

FIG. 9 is a schematic cross-sectional view showing a typical example of a conventional color sensor using an amorphous silicon pin junction.

Referring to FIG. 9, a conventional color sensor includes a transparent substrate 200 made of glass or the like, a transparent conductive film 202 formed on one surface of the transparent substrate 200, and a transparent conductive film 202 formed on the transparent conductive film 202. A p-type amorphous silicon film 204 containing a high concentration of p-type impurities, a high-resistance i-type amorphous silicon film 206 formed on the p-type amorphous silicon film 204, and an i-type An n-type amorphous silicon film 208 containing a high concentration of n-type impurities is formed on the amorphous silicon film 206, and a first electrode 210 is formed on the n-type amorphous silicon film 208.
and a first electrode 2 on the n-type amorphous silicon film 208.
]0, a third electrode 214 formed adjacent to the second electrode 212 on the n-type amorphous silicon film 208, and a light-transmitting Substrate 200
color filter section 2] 7 bonded on the other surface of
and an extraction electrode 216 provided on the transparent conductive film 202.

The color filter section 217 includes a transparent substrate 218, a first color filter 220 formed on one side of the transparent substrate 218, and a second color filter 220 formed adjacent to the first color filter 220. It includes a color filter 222 and a third color filter 224 formed adjacent to the second color filter 222 . The color filter section 217 is attached to the transparent substrate 200 so that the surface on which the color filters 220, 222, and 224 are formed is closely aligned with the transparent substrate 200.
pasted to 0.

The p-type amorphous silicon film 204, the l-type amorphous silicon film 206, and the n-type amorphous silicon film 208 are
CVD method (Chemical Vapor Dep.
position) method to form a pin junction.

The first electrode 210, the first color filter 220, the second
The electrode 212 and the second color filter 222, and the third electrode 2]4 and the third color filter 224 are arranged to face each other. The first -
photodiode PDI and a second photodiode P
D2 and a third four diode PD3 are formed.

In order to convert the color of the incident light into RGB components, the color filters 220, 222, and 224 are selected to transmit light in different wavelength ranges. −
As an example, the first color filter 220 is cyan,
A possible combination is that the second color filter 222 is magenta and the third color filter 224 is yellow.

The color sensor shown in FIG. 10 is a sectional view of another example of a conventional color sensor having a similar configuration to the color sensor shown in FIG. 9. The color sensor shown in FIG. 10 is different from the one shown in FIG. 9 because each color filter 220, 222, 224 is
It is directly formed on the surface opposite to the surface on which the amorphous silicon films 204 to 208 are formed.

The other parts of the color sensor shown in FIG. 10 are the same as those shown in FIG. 9. Corresponding elements in both figures are given the same reference numerals. To simplify the explanation, a detailed explanation of the structure of the color sensor shown in FIG. 10 will be omitted.

An equivalent circuit diagram of the color sensor shown in FIGS. 9 and 10 is shown in FIG. The operation of the conventional color sensor will be described below with reference to FIGS. 9-1.

Light enters the color sensor from the direction indicated by arrow R in FIGS. 9-10. A reverse bias voltage is applied in advance between the extraction electrode 216 and each of the electrodes 210, 212, and 214. First photodiode PDI
generates an electromotive force by the light transmitted through the first color filter 220. The second photodiode PD2 generates an electromotive force by the light transmitted through the second color filter 222. The third photodiode 1' PD 3 is
The light transmitted through the third color filter 224 generates an electromotive force.

If a current is drawn from each electrode 210.2]2.2]4, these represent the magnitudes of the three primary color components contained in the incident light. Therefore, the color sensor shown in FIGS. 9 and 10 can identify the color of light.

A photodiode using an amorphous silicon pin junction does not require a filter to cut off components in the infrared wavelength region. Color sensors using amorphous silicon can therefore be made smaller and lower in cost, and have a better future than those using crystalline silicon.

[Problems to be Solved by the Invention] However, the following problems have been pointed out regarding conventional color sensors using amorphous semiconductors such as amorphous silicon. The amorphous semiconductor film is formed by plasma CVD. At that time, the temperature of the substrate is 200°C ~ 2
The temperature can be raised to about 80°C. The materials that make up color filters are sensitive to high temperatures.

Therefore, if an amorphous semiconductor film is formed after forming a color filter, the color filter will be adversely affected. on the other hand,
When amorphous semiconductors are exposed to high temperatures after being formed, their electrical characteristics deteriorate. In contrast, color filters are generally formed at high temperatures. Therefore, it was necessary to keep the color filter and the amorphous semiconductor film as far apart as possible. In FIGS. 9 and 10, amorphous silicon films 204 to 208 and color filters 22
0.222.224 are arranged with the transparent substrate 200 in between for the above reason.

However, the transparent substrate 200 is made of, for example, glass, and has a thickness of 0.5 mm. It is about 7 to 1 mm. This thickness is quite large and causes the following disadvantages.

In FIG. 9, consider light incident on the third color filter 24 from the direction of arrow R'. Of this light, specific wavelength components are transmitted through the color filter 224. Originally, the light that passed through the third color filter 224 would be transmitted through the third color filter 224.
is incident on the photodiode PD3. However, light that enters the third color filter 224 obliquely, such as light that enters from the direction of arrow R', does not pass through the color filter 22.
After passing through the four diode PD2, the light may enter the second four diode PD2. This is due to the thickness of the transparent substrate 200.

Light that should originally generate an electromotive force in the third photodiode PD3 ends up being incident on the second photodiode PD2.

Therefore, the current extracted from the second photodiode PD2 and the third photodiode PD3 does not accurately represent the magnitude of each wavelength component of the incident light. That is, the wavelength components consisting of 71111 are determined to be too large, and the other wavelength components are determined to be too small. Therefore, in this color sensor, it is difficult to accurately measure the color of obliquely incident light.

This problem similarly occurs in the case of the color sensor shown in FIG.

Therefore, it is an object of the present invention to provide a color sensor using an amorphous semiconductor that can measure the color of obliquely incident light with small errors.

[Means for Solving the Problems] A color sensor according to the present invention is a color sensor for receiving visible light and converting light in a predetermined wavelength range included in the visible light into an electrical signal, The first point where light enters
and a second surface opposite to the second first surface, selectively transmitting light in the predetermined wavelength range of visible light to at least the second surface.
a transparent thin film conductor layer provided on a second surface of the color filter through which light passes; and a first conductive layer of a first conductivity type formed on the transparent thin film conductor layer a first amorphous semiconductor layer containing impurities at a concentration;
a second amorphous semiconductor layer formed on the amorphous semiconductor layer; and a second amorphous semiconductor layer formed on the second amorphous semiconductor layer and of a second conductivity type different from the first conductivity type. a third amorphous semiconductor layer containing impurities at a concentration of , and a conductor layer formed on the third amorphous semiconductor layer.

[Operation] Visible light to be measured is incident on the first surface of the color filter. Of the incident visible light, only light in a predetermined wavelength range reaches the second surface of the color filter and enters the transparent thin film conductor layer. The light incident on the transparent thin film conductor layer undergoes photoelectric conversion at the semiconductor junction formed by the first amorphous semiconductor layer, the second amorphous semiconductor layer, and the third amorphous semiconductor layer. Therefore, an electromotive force of a magnitude corresponding to the magnitude of the wavelength component selected by the color filter is generated between the transparent thin film conductor layer and the semiconductor layer.

The light incident obliquely on the first surface of the color filter enters the transparent thin film conductor layer and passes through the transparent thin film conductor layer obliquely, and the incident angle changes in the width direction of the transparent thin film conductor layer. The light enters the semiconductor junction from the transparent thin film conductor layer at a position that is displaced according to the magnitude of .

This displacement is small because the thickness of the transparent thin film conductor layer is small.

[Embodiment] FIG. 1 is a plan view of a color sensor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. FIG. 1 corresponds to a view taken along the line I--I in FIG. 2. In the following description, for convenience, the lower side of FIG. 2 will be referred to as the upper side. Referring to FIGS. 1 and 2, this color sensor includes a transparent substrate 10, a first color filter 12 made of polyimide formed on the transparent substrate 10, and a first color filter 12 made of polyimide formed on the transparent substrate 10.
A second color filter 14 formed of polyimide on a transparent substrate 10 adjacent to the color filter 12 of
and a third color filter 16 formed of polyimide on a transparent substrate 10'' adjacent to the second color filter 14 from the side opposite to the first color filter 12;
A first photodiode PDI formed on the first color filter 12, a second photodiode PD2 formed on the second color filter 14, and a second photodiode formed on the third color filter 16. 3 photodiodes PD3.

first color filter] 2 and second color filter 1
4 and the third color filter 16 are selected so as to transmit light of mutually different wavelengths.

The first photodiode PD] includes a transparent conductive film 18 formed on the first color filter 12 and a transparent conductive film 1 formed on the first color filter 12.
A first p-type amorphous silicon film 20 containing a high concentration of p-type impurity is formed covering the first p-type amorphous silicon film 20, and a first i-type an amorphous silicon film 22; a first n-type amorphous silicon film 24 formed on the first i-type amorphous silicon film 22 and containing a high concentration of n-type impurities; A metal electrode film 26 formed on an amorphous silicon film 24 is included.

The second photodiode PD2 also has a similar structure to the first photodiode PDI. The second photodiode PD2 includes a thin second transparent conductive film 28 formed on the second color filter 14 and a second transparent conductive film 2 formed on the second color filter 14.
a second p-type amorphous silicon film 30 formed on 8;
A second l-type amorphous silicon film 32 provided on the second p-type amorphous silicon film 30 and a second n-type non-crystalline silicon film 32 formed on the second i-type amorphous silicon film 30. A second silicon film formed on the crystalline silicon film 36 and the second n-type amorphous silicon film 36
metal electrode film 38.

The third photodiode PD3 has a similar structure to the first photodiode PDL and the second photodiode PD2. The third photodiode PD3 includes a third transparent conductive film 40 formed on the third color filter 16 and a third p-type amorphous silicon film formed on the third transparent conductive film 40. 42, and a third 1-type amorphous silicon film 4 formed on the third p-type amorphous silicon film 42.
4, a third n-type amorphous silicon film 46 formed on the third l-type amorphous silicon film 44, and a metal formed on the third n-type amorphous silicon film 46. and an electrode film 48.

The first photodiode PDI is provided with an extraction electrode 18a of the transparent conductive film 18 and an extraction electrode 26a of the metal electrode film 26. The second photodiode PD2 is provided with an extraction electrode 28a of the transparent conductive film 28 and an extraction electrode 38a of the metal electrode film 38. The third photodiode PD3 is provided with an extraction electrode 40a of the transparent conductive film 40 and an extraction electrode 48a of the metal electrode film 48.

The operation of this color sensor will be explained with reference to FIGS. 1 and 2. A reverse bias voltage is applied in advance between the first transparent conductive film 18 and the first metal electrode film 26.

Between the second transparent conductive film 28 and the second metal electrode film 38,
A reverse bias voltage is also applied in advance between the third transparent conductive film 40 and the third metal electrode film 48.

Light enters from the direction indicated by arrow R in FIG. The light passes through the translucent substrate ] 0 and enters the first color filter 12 , the second color filter ] 4 , and the third color filter 16 .

The first color filter 12 transmits only light in a predetermined wavelength range among the incident light. The light that has passed through the first color filter 12 also passes through the transparent conductive film 18 and enters the first p-type amorphous silicon film 20 . At the pin junction formed by the p-type amorphous silicon film 20, the i-type amorphous silicon film 22, and the n-type amorphous silicon film 24, photoelectric conversion occurs due to the incident light.

Therefore, an electromotive force is generated in the photodiode PDI, and if a circuit is provided to connect the transparent conductive film 8 and the metal electrode film 26, a current flows. The magnitude of this current indicates the magnitude of light in a specific wavelength range that is incident on the first diode PDI.

In the second photodiode PD2 and the third photodiode PD3, the color filter 14.1 is also used.
An electric signal is generated according to the magnitude of light in a specific wavelength range selected by 6.

The first to third color filters 12, 14, and 16 are selected to transmit light in different wavelength ranges, for example, those corresponding to the three primary colors of light. Therefore, the color of the light incident on this color sensor can be identified from the electrical signals output from the photoI diodes PDI, PD2, and PD3.

Conventionally, between the pin joint and the color sensor, 0,
There are light-transmitting substrates having a thickness of about 7 to 1 mm. Therefore, if light enters the color sensor obliquely, accurate color discrimination cannot be performed.

In contrast, in this embodiment, there is only a transparent conductive film made of a thin film with a thickness of several hundred to several thousand layers between the color filter and the pin junction.

Therefore, even if light is obliquely incident on the color sensor, the light that has passed through the color filter will not be incident on other adjacent photodiodes. The color of the incident light is accurately measured by this color sensor.

Each amorphous silicon film is formed by plasma CVD as described above.
Formed by law. Therefore, the substrate temperature during manufacturing increases to about 200°C to 280°C. The material of the color filter needs to be set with heat resistance in mind. In this example, a color sensor with good performance was realized by using a polyimide color filter and taking advantage of its heat resistance of 250° C. or higher.

FIG. 3 is a graph showing the spectral sensitivity characteristics of the color sensor shown in FIGS. 1 and 2. FIG. FIG. 3 shows the spectral sensitivity of each photodiode PDI, PD2, and PD3.

As shown in FIG. 3, each photodiode has good spectral characteristics for measuring incident light in three wavelength regions defined by color filters.

FIG. 4 is a plan view of a color sensor according to another embodiment of the invention. FIG. 5 is a sectional view of FIG. FIG. 4 corresponds to the IV-IV direction arrow view of FIG.

Referring to FIGS. 4 and 5, this color sensor includes a metal substrate 50, three photodiodes PD4, PD5, and PD6 formed on the metal substrate 50, and a photodiode provided on the photodiode PD4. a first color filter 52;
It includes a second color filter 54 provided above the photodiode PD5 and a third color filter 56 provided above the photodiode PD6.

The photodiode PD4 is formed on a metal substrate 50 and includes an n-type amorphous silicon film 58 containing a high concentration of n-type impurities.
, a high-resistance type 1 amorphous silicon film 60 formed on the n-type amorphous silicon film 58 , and an i-type amorphous silicon film 6
a p-type amorphous silicon film 62 formed on the p-type amorphous silicon film 62 and containing a high concentration of n-type impurities; a transparent conductive film 64 formed on the p-type amorphous silicon film 62; A metal film is provided on the transparent conductive film 64 and the color filter 52 at a predetermined height on the transparent conductive film 64 to prevent light that does not pass through the color filter 52 from directly entering the light receiving area formed by the pin junction. 52.

The second photodiode PD5 and the third photodiode PD6 also have similar configurations. The second photodiode PD5 is formed on a metal substrate 50''2 and has a high concentration of n.
n-type amorphous silicon containing type impurities] 9 silicon film 68, a high-resistance i-type amorphous silicon film 70 formed on the n-type amorphous silicon film 68, and an i-type amorphous silicon film A p-type amorphous silicon film 72 containing a high concentration of n-type impurities, a transparent conductive film 74 formed on the p-type amorphous silicon film 72 and a p-type amorphous silicon film Second, a metal film 72 is provided at a predetermined height to surround the transparent conductive film 74 and the color filter 54 and to prevent light that does not pass through the color filter 54 from directly entering the light receiving area formed by the pin junction. membrane 76.

The third photodiode PD6 is formed on the metal substrate 50 and includes an n-type amorphous silicon film 78 containing a high concentration of n-type impurity, and a high-resistance film 78 formed on the n-type amorphous silicon film 78. A 1-type amorphous silicon film 80, a p-type amorphous silicon film 82 formed on the l-type amorphous silicon film 80 and containing a high concentration of n-type impurities, and a p-type amorphous silicon film 82 formed on the p-type amorphous silicon film 82. The transparent conductive film 84 and the p-type amorphous silicon film 82 formed in
A metal film 86 is provided at a predetermined height to prevent light from directly entering the light receiving area formed by the in-junction.

Each color filter 52, 54, 56 is selected to transmit light of a different wavelength and is made of epoxy.

The operation of the color sensor shown in FIGS. 4 and 5 will now be described. Light is transmitted from each photodiode PD4, PD
5. The light enters the PD 6 from the direction of the color filters 52, 54, and 56. The metal films 66, 76, 86 prevent light that does not pass through the color filters 52, 54, 56 from entering each light receiving area. Color filter 52.54.56
The light transmitted through the transparent conductive films 64, 74, and 84 enters the pin junction of each photodiode.

The light transmitted through the color filter 52 causes the first photodiode PD4 to connect the transparent conductive film 64 and the metal substrate 50.
An electromotive force is generated between the Second photodiode PD
5 generates an electromotive force between the transparent conductive film 74 and the metal substrate 50. The third photodiode PD6 generates an electromotive force between the transparent conductive film 84 and the metal substrate 50.

The electromotive force generated by each of these diodes PD4, PD5, and PD6 is generated by the color filter 52.
54 and 56 respectively represent the magnitude of the selected wavelength component.

The color filters 52, 54, 56 are made of epoxy. Color filter 52, 54, 56 is 250℃
It is formed at relatively low temperatures, such as: Each amorphous silicon film has already been formed before forming the color filters 52, 54, 56. However, the characteristics of each amorphous silicon film are not adversely affected at this level of temperature during the production of color filters.

In this embodiment, as in the first embodiment, only a thin transparent conductive film is present between the color filter and the pin junction. As a result, it is possible to provide a color sensor that can accurately measure the color components even if light is incident obliquely on each color filter.

FIG. 6 is a graph showing the spectral sensitivity characteristics of the color sensor of this second embodiment. As shown in Figure 6,
Even if an epoxy color filter is used, a color sensor having good spectral sensitivity for each color component can be obtained.

FIG. 7 is a plan view of a color sensor according to another embodiment of the invention. FIG. 8 is a cross-sectional view taken along arrows ``--'' in FIG. 7. FIG. 7 corresponds to the ■■ force direction arrow view in FIG. 8. Referring to FIGS. 7 and 8, this color sensor includes an opaque insulating substrate 88 made of organic polymer or the like, a photodiode PD7 formed on the insulating substrate 88',
a photodiode PD8 formed on an insulating substrate 88 adjacent to the photodiode PD7; a photodiode PD9 formed on the insulating substrate 88 adjacent to the photodiode PD8 from the opposite direction to the photodiode PD7; A first color filter 9 formed on the photodiode PD7 to cover the photodiode PD7.
0, a second color filter 92 formed over the photodiode PDg and covering the photodiode PD8, and a second color filter 92 formed over the photodiode PDQ.
9, and a third color filter 94 formed to cover the color filter 9.

Each color filter 90, 92, 94 is selected to transmit light in different wavelength ranges.

The photodiode PD7 is formed on a metal electrode film 96 formed on an insulating substrate 88 and on the metal electrode film 96,
N-type amorphous silicon film 98 with high concentration of n-type impurities
, a high-resistance l-type amorphous silicon film 100 formed on the n-type amorphous silicon film 98, and a p-type amorphous silicon film 100 formed on the i-type amorphous silicon film 100 and having a high concentration of p-type impurities. type amorphous silicon film 102 and p-type amorphous silicon film]0
A transparent conductive film 104 formed on 2.

The photodiode PD8 includes a metal electrode film 106 formed on an insulating substrate 88, an n-type amorphous silicon film formed on the metal electrode film]06 and having a high concentration of n-type impurities]08, A high resistance i-type amorphous silicon film 110 formed on the type 1 amorphous silicon film 108 and a p-type amorphous silicon film 110 formed on the type 1 amorphous silicon film 110 and having a high concentration of p-type impurities. The transparent conductive film 14 includes a transparent conductive film 112 formed on the p-type amorphous silicon film 112.

The photoI diode PD9 includes a metal electrode film 1]6 formed on an insulating substrate 88, and an n-type amorphous silicon film formed on the metal electrode film]]6 and having a high concentration of n-type impurities. 118, a high-resistance l-type amorphous silicon film 120 formed on the n-type amorphous silicon film 118, and a high-resistance l-type amorphous silicon film 120 formed on the l-type amorphous silicon film 120 and having a high concentration of p-type impurities. It includes a p-type amorphous silicon film 122 and a transparent conductive film formed on the p-type amorphous silicon film 122.

Each metal electrode film 96, 106, 116 is formed in a predetermined pattern. Metal electrode film 96.106,1
1.6 has electrode extraction parts 96a and 106a, respectively.
, 11.6a are provided. Transparent conductive film 104. ]i,
4, 1.24, electrode extraction portion 104a,
1.1.4a, 124a are provided.

In the color sensor shown in FIGS. 7 and 8, light enters each photodiode PD7, PD8, PD9 from the color filter 90, 92, 94 side. Since the color filter 90 covers the photodiode PD7, the color filter 90 covers the photodiode PD7.
Only light in a predetermined wavelength range selected by 0 is incident.

In the photodiode PD7, the incident light is photoelectrically converted at the pin junction consisting of the p-type amorphous silicon film 102, the i-type amorphous silicon film 100, and the n-type amorphous silicon film 98, and is converted into a metal electrode film. An electromotive force is generated between the transparent conductive film 96 and the transparent conductive film 04. Similarly, in the PD 8, an electromotive force is generated between the metal electrode film 106 and the transparent conductive film 14. In the photodiode PD9, an electromotive force is generated between the metal electrode film 116 and the transparent conductive film 24.

The electromotive force of each of these photodiodes PD7, PD8, and PD9 corresponds to the size of the light that has passed through the color filters 90192 and 94, respectively.

A transparent conductive film 04 made of a thin film is provided between the color filter 90 and the p-type amorphous silicon film 102. Color filter 92 and p-type amorphous silicon film] 12
A transparent conductive film 114 is provided between the two. A transparent conductive film 124Z is provided between the color filter 94 and the p-type amorphous silicon film 122. Each of these transparent conductive films 104, 114, and 124 has a sufficiently thin film thickness.

Therefore, even if there is light obliquely incident on each filter, this color sensor can accurately measure the color.

In the apparatus shown in FIGS. 7 and 8, the metal electrode film 96
．． If a metal film is formed on the entire surface of the insulating substrate 88 without patterning 106 and 116, the same structure as the second embodiment will be obtained. Further, in the second embodiment, if an insulating film is formed on the metal substrate 50'2 and then a metal electrode film is formed by patterning, a structure similar to that of the third embodiment can be obtained.

In any of the color sensors of the first to third embodiments, the color filter and the photodiode pi
It is separated from the n-junction only by a thin transparent conductive film. Therefore, even if there is light that enters the color filter from an angle, the probability that the light will enter a photodiode that does not correspond to the color filter is much smaller than in the past. Most of the light is incident on the correct photodiode corresponding to each color filter.

As a result, the color sensor can more accurately identify the color of light.

[Effect] After the light that is obliquely incident on the first part of the color filter enters the transparent thin film conductor layer, it is reflected in the width direction of the transparent thin film conductor layer.
The light enters the pin junction from the transparent thin film conductor layer at a position displaced according to the magnitude of the incident angle. This displacement is small because the thickness of the transparent thin film conductor layer is small. In particular, its thickness is about 1/1000th of the thickness of conventional glass substrates. Therefore, there is little possibility that the light that has obliquely entered the color filter will enter not the correct photodiode but another adjacent photodiode. Therefore, the 411 determination of the components of each wavelength region of light by this color sensor is performed correctly. On the other hand, by appropriately selecting the order in which the amorphous silicon films, transparent thin film conductor layers, and color filters are formed and their constituent materials, a color sensor with good spectral sensitivity characteristics can be constructed.

That is, it is possible to provide a color sensor using an amorphous semiconductor that can measure the color of obliquely incident light with small errors.

[Brief explanation of drawings]

FIG. 1 is a plan view of a color sensor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 4 is a graph showing the spectral sensitivity characteristics of the color sensor shown in FIG. 4, FIG. 4 is a plan view of a color sensor according to another embodiment of the present invention, and FIG. FIG. 6 is a graph showing the spectral sensitivity characteristics of the color sensor shown in FIGS. 4 and 5, and FIG. 7 is a plan view of a color sensor according to still another embodiment of the present invention. FIG. 8 is a cross-sectional view of FIG. 7 taken along the direction arrow ■-■, FIG. 9 is a cross-sectional view of an example of a conventional color sensor, and FIG. 10 is a cross-sectional view of another example of a conventional color sensor. FIG. 11 is an equivalent circuit diagram of the color sensor shown in FIGS. 9 and 10. In the figure, 10 is a transparent substrate, 12.14.16.52.54
．． 56.90.92.94 is a color filter, 18.2
8.40.64.74.84.104.114,]24
is a transparent conductive film, 20.30.42.62.72.82.
102, ]12.122 is a p-type amorphous silicon film, 22
．． 32.44.60.70.80.100.110,]
20 is an l-type amorphous silicon film, 24.36.46.58
．． 68.78.98.108.1] 8 is an n-type amorphous silicon film, 26.38.48.96.106.116 is a metal electrode film, 50 is a metal substrate, 66.76.86 is a metal film, 88 indicates an insulating substrate. Note that the same reference numerals in the figures indicate the same or equivalent parts. 1 (υ uniform photo 1,000 pages) 1 λ 1 ρ kuri (all people with disabilities) 1 meal C to seconds

Claims (1)

[Claims] (1) A color sensor for receiving visible light and converting light in a predetermined wavelength range included in the visible light into an electrical signal, the sensor comprising: a first surface on which the visible light is incident; a color filter having a first surface and a second surface opposite to each other, the color filter selectively transmitting light in the predetermined wavelength range of the visible light to at least the second surface; a transparent thin film conductor layer through which light passes, provided on the surface of the transparent thin film conductor layer, and a first conductive layer of a first conductivity type formed on the transparent thin film conductor layer;
a first amorphous semiconductor layer containing impurities at a concentration of; a second amorphous semiconductor layer formed on the first amorphous semiconductor layer; and a second amorphous semiconductor layer formed on the second amorphous semiconductor layer. a third amorphous semiconductor layer formed on the third amorphous semiconductor layer and containing impurities of a second concentration and of a second conductivity type different from the first conductivity type; A color sensor comprising a conductive layer.