WO2014002591A1

WO2014002591A1 - Ultraviolet detection device and electronic apparatus

Info

Publication number: WO2014002591A1
Application number: PCT/JP2013/061801
Authority: WO
Inventors: 大西　雅也
Original assignee: シャープ株式会社
Priority date: 2012-06-27
Filing date: 2013-04-22
Publication date: 2014-01-03
Also published as: JP2015165184A

Abstract

An ultraviolet detection device comprises: a color change layer (401) which changes color according to the amount of ultraviolet light; a first color detection sensor (102) which detects the color of the color change layer (401); and a second color detection sensor (502) which detects the color of external visible light. By correcting an output value from the first color detection sensor (102) by an output value from the second color detection sensor (502), the amount of ultraviolet light can be accurately obtained as electronic information without being influenced by changes in the color of external incident light.

Description

Ultraviolet detector and electronic device

The present invention relates to an ultraviolet detection device and an electronic device equipped with the same.

In recent years, the market fields of home appliances and electronic devices related to the health environment have expanded, and in particular, due to changes in the global environment, there has been an increasing interest in the amount of ultraviolet rays received from the sun when going out. As a method for easily obtaining the intensity of the amount of ultraviolet light, a material that changes color according to the amount of ultraviolet light, and an ultraviolet detection device including the material have been proposed.

Conventionally, as this type of ultraviolet detection device, there is one described in Patent Document 1 (Japanese Patent Laid-Open No. 2007-278904). This ultraviolet ray detection device includes a color change display body containing an organic photochromic substance, and a detector visually determines a color change corresponding to the ultraviolet ray amount of the color change display body to obtain an ultraviolet ray amount. .

However, the above-described ultraviolet detection device has a problem in that the amount of ultraviolet rays cannot be accurately obtained as an electrical signal because the color change corresponding to the amount of ultraviolet rays of the color change display body is visually determined.

On the other hand, UV (ultraviolet) sensors using GaAsP photodiodes or GaN Schottky diodes are commercially available as ultraviolet detectors that obtain the amount of ultraviolet rays as an electrical signal. This UV sensor can obtain an electrical signal according to the amount of ultraviolet rays, and can obtain ultraviolet information with higher accuracy than visual color determination.

However, the UV sensor has a problem that it is expensive because it requires a GaAsP photodiode or a GaN Schottky diode. In particular, in a portable electronic device, when this UV sensor is used for detecting the amount of ultraviolet rays, it is necessary to mount expensive non-silicon-based electronic components such as GaAsP photodiodes, which can be adopted cost-effectively. There is a problem that you can not.

Note that although general-purpose silicon ICs (integrated circuits) are inexpensive, they can hardly obtain sensitivity to ultraviolet rays, so the GaAsP photodiodes, GaN Schottky diodes, and the like are required even if they are expensive.

Therefore, as a relatively inexpensive ultraviolet detection device, there is one described in Patent Document 2 (Japanese Patent Laid-Open No. 2010-243252). This ultraviolet ray detection device is provided with a light control lens whose discoloration density changes according to the amount of received ultraviolet light in the housing, and a light source that irradiates a side surface of the light control lens with a certain amount of light in the housing; A light receiving element that receives light from a light source that has passed through the light control lens is disposed. Then, the color change density of the light control lens according to the amount of ultraviolet light is detected by the change in the amount of light received by the light receiving element, and an electric signal representing the amount of ultraviolet light is obtained.

However, when the ultraviolet detection device is mounted on a portable electronic device or the like, a light source such as a light-emitting diode with a constant light amount for detection is required, so that the portable electronic device requires a large mounting area and is constant. Since a light source having a light amount is necessary, there is a problem that it is still expensive.

JP 2007-278904 A JP 2010-243252 A

Accordingly, an object of the present invention is to obtain an electrical signal that accurately represents the amount of ultraviolet rays, and does not require a light emitting element for a light source with a constant light amount, and has a small mounting area and is inexpensive. An object of the present invention is to provide a detection device and an electronic apparatus including the same.

In order to solve the above problems, the ultraviolet detection device of the present invention is:
A color changing layer that changes color according to the amount of ultraviolet rays received from the outside;
A first color detection sensor for detecting the color of the discoloration layer,
The presence or absence of ultraviolet rays or the amount of ultraviolet rays is detected based on the hue of the color changing layer detected by the first color detection sensor.

In the ultraviolet detection device having the above configuration, the discoloration layer changes color according to the amount of external ultraviolet rays, and the color of the discoloration change layer is detected by the first color detection sensor. It is accurately detected by an electrical signal from one color detection sensor.

As described above, this ultraviolet ray detection device does not directly detect ultraviolet rays, but detects the amount of ultraviolet rays by detecting the hue of the discoloration layer changed in accordance with the amount of ultraviolet rays with the first color detection sensor. Therefore, the first color detection sensor can be constituted by an inexpensive silicon-based general-purpose semiconductor element without requiring an expensive non-silicon-based diode such as a GaAsP photodiode or a GaN Schottky diode. The detection device itself can be manufactured at a low cost.

Furthermore, in this ultraviolet ray detection apparatus, the first color detection sensor detects the hue of the discolored layer that has changed color in accordance with the amount of ultraviolet ray from the outside, detects the ultraviolet ray amount based on that hue, Since the amount is not detected, a light source such as a light emitting diode having a constant light amount is not required separately, and the number of parts is reduced accordingly. Therefore, this ultraviolet ray detection device is inexpensive because it has a small number of parts, and has the advantage of a small mounting area when mounted on an electronic device.

In portable electronic devices such as mobile phones, the function of detecting and displaying the amount of ultraviolet rays is not an absolutely necessary function in many cases, so it is compact without increasing the number of electronic components of the portable electronic device. There is a strong demand for detecting the amount of ultraviolet rays as an electrical signal with a simple and inexpensive configuration. The present invention meets that need.

Note that the first color detection sensor may detect the hue of the color changing layer by the transmitted light from the color changing layer, or may detect the color of the color changing layer by the reflected light from the color changing layer.

In one embodiment,
The discoloration layer transmits external visible light, the first color detection sensor detects the color of the transmitted light of the discoloration layer, and the presence or absence of ultraviolet rays depending on the color of the transmitted light according to the color of the discoloration layer Detects the amount of ultraviolet light.

According to the above-described embodiment, the color of the external visible light that has passed through the discoloration layer is detected by the first color detection sensor, and the presence or absence of ultraviolet rays or the amount of ultraviolet rays is detected. As described above, since the hue of the color changing layer is detected based on the color of the external visible light transmitted through the color changing layer, it is possible to accurately detect the color of the color changing layer and accurately detect the presence or the amount of ultraviolet light. .

Further, according to this embodiment, the first color detection sensor is disposed at a position for receiving the external visible light transmitted through the color change layer, so that the first color detection sensor is changed in color by ultraviolet rays. Therefore, the discoloration layer having a function of shielding ultraviolet rays protects from ultraviolet rays from the outside and prevents the damage.

In one embodiment,
A second color detection sensor for detecting the color of external visible light received from the outside;
The output value of the first color detection sensor corresponding to the hue of the discoloration layer is corrected by the output value of the second color detection sensor corresponding to the hue of external visible light.

In this embodiment, the output value from the first color detection sensor corresponding to the color of the discoloration layer is corrected by the output value from the second color detection sensor corresponding to the color of the external visible light. Therefore, the influence of the change in the hue of the external visible light on the hue of the color changing layer can be removed, and the change in the hue specific to the color changing layer can be accurately detected, and the presence or absence of ultraviolet rays or the amount of ultraviolet rays can be obtained as electronic information with high accuracy it can.

For the correction of the output value of the first color detection sensor, for example, the output value of the second color detection sensor may be subtracted from the output value of the first color detection sensor, or the second color detection sensor. This is performed by subtracting the output value by a certain coefficient.

In one embodiment,
The first and second color detection sensors are RGB color sensors that detect the amount of red light, green light, and blue light,
The output values of red (R), green (G), and blue (B) output from the first color detection sensor are used as red (R), green (G), and blue output from the second color detection sensor. Correction is performed based on the output value of (B).

In the above embodiment, since the first and second color detection sensors are RGB color sensors, general-purpose products can be used, and they are simple and inexpensive, and red (R), green (G), blue ( The output value of B) can be corrected, and the hue can be accurately detected.

In one embodiment,
With illuminance detection means for detecting the illuminance of external visible light,
The amount of ultraviolet rays based on the variation of the output value of the first color detection sensor from the initial value of the first color detection sensor when the illuminance detected by the illuminance detection means is lower than a predetermined value. Correct the calculation of.

In the above embodiment, the initial value when the first color detection sensor has no ultraviolet light (for example, a value at the time of factory shipment) and the illuminance of the external visible light detected by the illuminance detection means are predetermined values. The calculation of the amount of ultraviolet rays is corrected based on the amount of fluctuation from the output value of the first color detection sensor when the value is lower than the first value.

When the illuminance of external visible light is low, that is, when the illuminance of external visible light is lower than a predetermined value, the environment is low in ultraviolet rays.

In this embodiment, the calculation of the amount of ultraviolet rays is corrected based on the variation from the initial value of the output value of the first color detection sensor when the illuminance of external visible light is lower than a predetermined value. Therefore, even if the discoloration layer deteriorates due to secular change or the like, the influence can be compensated.

Thus, in this embodiment, since the color state of the discoloration layer is confirmed and corrected at low illuminance, which is an environment with little ultraviolet light, the absolute amount of ultraviolet light can be detected with high accuracy.

The illuminance detection means may be provided integrally with the first color detection sensor or may be provided separately. Or you may share the illumination intensity sensor which the existing portable electronic device has as this illumination intensity detection means.

Also, one embodiment is
With a housing,
A first color detection sensor is provided in the enclosure,
The discoloration layer partitions the inside and outside of the housing to protect the first color detection sensor from ultraviolet rays.

In the above embodiment, the first color detection sensor is provided in the casing because the color changing layer partitions the inside and outside of the casing and detects the color of the color changing layer. The housing and the discolored layer are protected from ultraviolet rays and are prevented from being damaged.

In one embodiment,
The first and second color detection sensors have red, green, and blue filters, respectively.
The red, green and blue filters are formed on the same silicon substrate and arranged adjacent to each other.

In the above embodiment, the red, green and blue filters of the first and second color detection sensors are formed on the same silicon substrate and arranged adjacent to each other. The color detection sensors of the first color detection sensor are in the same state and receive the same ultraviolet rays, visible rays, infrared rays, etc., so the output value of the first color detection sensor for detecting the hue of the discoloration layer is used as the output value of the second color detection sensor. The output value can be corrected with high accuracy.

The electronic device of the present invention is
The above-described ultraviolet detection device is provided.

Since this electronic device is equipped with the above-described ultraviolet detection device, it can detect the amount of ultraviolet rays accurately, and is small and inexpensive.

The ultraviolet detection device of the present invention does not directly detect the amount of ultraviolet rays, but detects the amount of ultraviolet rays by detecting the hue of the color changing layer that changes color according to the amount of ultraviolet rays with the first color detection sensor. In addition, the amount of ultraviolet rays can be accurately obtained as an electric signal, and an expensive non-silicon diode such as a GaAsP photodiode or a GaN Schottky diode is not required, and the first color detection sensor is a silicon-based inexpensive. It can be manufactured with a semiconductor element and has the advantage of being inexpensive.

Further, the ultraviolet ray detection device of the present invention detects the hue of the discoloration layer changed in color according to the amount of ultraviolet ray from the outside by the first color detection sensor, detects the amount of ultraviolet ray by the hue, and transmits the transmitted light amount. The amount of ultraviolet rays is not detected by the light source, so there is no need for a separate light source such as a light-emitting diode, a small number of parts, low cost, and a small mounting area on the electronic device. Have.

Since the electronic apparatus of the present invention includes the above-described ultraviolet detection device, it has the advantages of being able to accurately detect the amount of ultraviolet rays and being small and inexpensive.

1 is a schematic diagram of an ultraviolet detection device according to a first embodiment of the present invention. It is a figure which shows the output characteristic of the 1st color detection sensor of the said ultraviolet-ray detection apparatus. FIGS. 3A and 3B are diagrams showing a state in which there is no external ultraviolet light and a state in which external ultraviolet light is present in the ultraviolet detection device. 4A and 4B are diagrams illustrating output characteristics of the first color detection sensor corresponding to the states of FIGS. 3A and 3B. It is a schematic diagram which shows the state which has no external ultraviolet-ray of the ultraviolet-ray detection apparatus of 2nd Embodiment of this invention. FIGS. 6A and 6B are diagrams showing output characteristics of the first and second color detection sensors of the ultraviolet ray detection apparatus in a state where there is no external ultraviolet ray. It is a schematic diagram which shows the state which has the external ultraviolet-ray of the ultraviolet-ray detection apparatus of 2nd Embodiment of this invention. FIGS. 8A and 8B are diagrams showing output characteristics of the first and second color detection sensors of the ultraviolet detection device in the presence of the external ultraviolet rays. It is a block diagram of the principal part of the ultraviolet-ray detection apparatus of 3rd Embodiment of this invention. It is a perspective view of the portable information terminal of 4th Embodiment of this invention. It is a perspective view of the ultraviolet-ray detection apparatus of 5th Embodiment of this invention.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
As shown in FIG. 1, the ultraviolet detection device according to the first embodiment includes a color change layer 101 that changes color according to the amount of ultraviolet light, and a first color detection sensor 102 that detects the hue of the color change layer 101. The first color detection sensor 102 detects the hue of the transmitted light 105 transmitted through the color changing layer 101.

For example, the discoloration layer 101 is applied to a transparent resin, glass, transparent film, or the like, or mixed with a transparent resin, glass, transparent film, or the like, by applying a photochromic material that changes color according to the amount of ultraviolet light when irradiated with ultraviolet light. Or formed.

The first color detection sensor 102 is an RGB color sensor that detects the amount of red (R) light, green (G) light, and blue (B) light, and is composed of a general-purpose silicon IC (integrated circuit). Although not shown, the first color detection sensor 102 has red, green, and blue filters and photodiodes, and receives light reception signals from the respective photodiodes according to the amounts of received light of red, green, and blue. (Photocurrent) is output.

FIG. 2 shows an output (light quantity) with respect to the wavelength of the light received by the first color detection sensor 102. In FIG. 2, it is assumed that the wavelength distribution of R (red), G (green), and B (blue) of the amount of input light to the first color detection sensor 102 is uniform. In this case, the first color Outputs of R, G, and B of the detection sensor 102 are equalized to have waveforms indicated by R, G, and B in FIG. The areas of the waveforms indicated by R, G, and B in FIG. 2 are obtained as output values that represent the received light amounts of R, G, and B, that is, electrical signals that represent the color of the discoloration layer 101.

Although not shown, the ultraviolet detection device of the first embodiment is mounted on a portable electronic device such as a mobile phone, a portable information terminal, or a game machine.

In the ultraviolet detection device having the above configuration, it is assumed that external light such as sunlight is incident on the color changing layer 101 from the outside of the portable electronic device as shown in FIG.

Note that external light such as sunlight includes ultraviolet light, visible light, and infrared light, but in FIG. 1, the infrared light is omitted and only the external ultraviolet light 103 and the external visible light 104 are shown.

Then, the color change layer 101 changes color according to the amount of the external ultraviolet light 103, while the first color detection sensor 102 receives the transmitted light 105 from the color change layer 101 and the color of the color change layer 101 before the color change. And the color after the color change is detected. Then, the amount of external ultraviolet rays can be detected and confirmed by comparing the hue before and after the color change of the color change layer 101.

More specifically, the output value of the first color detection sensor 102 representing the hue of the color changing layer 101 in the absence of the external ultraviolet light 103 is stored in advance in a memory (not shown) as an initial value, and then this memory Is compared with the output value of the first color detection sensor 102 representing the hue of the color-changing layer 101 in a state after the hue is changed by the irradiation with the external ultraviolet light 103 by a comparison unit (not shown). Thus, the presence or absence of the external ultraviolet light 103 can be confirmed, or the amount of the external ultraviolet light 103 can be calculated.

The operation of the ultraviolet detection device of the first embodiment will be described more specifically with reference to FIGS.

Although materials that cause various color changes have been developed as photochromic materials, here, it is assumed that the color changing layer 101 changes from red to green as the amount of external ultraviolet light 103 increases.

FIG. 3A shows a state in which there is no external ultraviolet light and the color changing layer 101 is red, and FIG. 3B shows that there is an external ultraviolet light 103 and the color changing layer 101 is green. Indicates the state. 4A and 4B are diagrams showing output waveforms of the first color detection sensor 102 corresponding to the states of FIGS. 3A and 3B.

As shown in FIG. 3A, when there is no external ultraviolet ray, the color changing layer 101 is red, and the transmitted light 205 from the color changing layer 101 is a red component (λ = 620 nm region) as shown in FIG. The amount of light) increases.

Next, as shown in FIG. 3B, when the amount of the external ultraviolet light 103 is increased, the color changing layer 101 becomes green, and the transmitted light 105 from the color changing layer 101 is shown in FIG. 4B. As described above, the green component (the amount of light in the λ = 540 nm region) increases.

Accordingly, the output values of the first color detection sensor 102 are as shown in FIGS. 4A and 4B, and the red component (R) and the green component (B) are respectively shown in FIG. By comparing the initial value shown and the value at the time of measurement shown in FIG. 4B, the presence or absence of ultraviolet rays can be confirmed and the amount of ultraviolet rays can be calculated.

In the ultraviolet detection device according to the first embodiment, the first color detection sensor 102 detects the hue of the discoloration layer 101 that changes color by ultraviolet rays to obtain the presence or absence of ultraviolet rays or the amount of ultraviolet rays. In addition to being able to be obtained accurately as electronic information, there is no need to add an electronic component such as a light emitting element as a light source, and there is an advantage that it is small, compact and inexpensive.

In particular, when the ultraviolet detection device of the first embodiment is mounted on an electronic device such as a mobile phone or a portable information terminal, there is an advantage that the mounting area is small.

In addition, the ultraviolet detection device of the first embodiment does not directly measure the amount of ultraviolet rays, but detects the hue of the discoloration layer 101 that changes color according to the amount of ultraviolet rays by the first color detection sensor 102. An inexpensive general-purpose silicon photodiode can be used for the first color detection sensor 102, which has the advantage of being inexpensive.

(Second Embodiment)
By the way, when the incident light is sunlight, the actual color of the incident visible light varies depending on time or the influence of the weather, the color of a shield such as a roof, or the like. Therefore, the ultraviolet detection device of the first embodiment has a problem that the amount of ultraviolet rays can be stably measured only in the daytime when the daytime ultraviolet rays are strong, and the environment during measurement is limited. is there.

The ultraviolet detector according to the second embodiment is capable of accurately detecting the amount of ultraviolet rays without any restriction in the environment during measurement. FIG. 5 is a diagram showing a state in which there is no external ultraviolet rays in the ultraviolet detection device of the second embodiment, and FIG. 7 is a diagram showing a state in which there is external ultraviolet rays in the ultraviolet detection device of the second embodiment.

As shown in FIGS. 5 and 7, the ultraviolet detection device of the second embodiment includes a color changing layer 401 that changes color from red to green according to an increase in the amount of external ultraviolet rays 603, and external visible light 404 that is incident from the outside. A visible light transmitting layer 501 that transmits 604; a first color detection sensor 102 that detects the color of the color changing layer 401 through transmitted light 405 and 605; and a transmitted light 505 that transmits the visible light transmitting layer 501. , 705, and a second color detection sensor 502 for detecting the hue. The visible light transmission layer 501 does not change color depending on ultraviolet rays, and transmits the external visible light 404 and 604 almost as it is with a slight attenuation.

The discoloration layer 401 and the visible light transmission layer 501 are made of, for example, a photochromic material that changes color from red to green in accordance with an increase in the amount of ultraviolet rays in a portion corresponding to the discoloration layer 401 in the same glass layer or transparent resin layer. By coating and forming, they are located on substantially the same plane and are integrally formed.

However, the discoloration layer 401 and the visible light transmission layer 501 may be formed separately and adjacent to each other. Further, the discoloration layer 401 and the visible light transmission layer 501 are not limited to the structure and formation method described above, and may be anything.

The first and second color detection sensors 102 and 502 are manufactured from general-purpose silicon ICs (integrated circuits). The first color detection sensor 102 is for detecting the hue of the color changing layer 101 that changes from red to green according to the amount of ultraviolet rays, whereas the second color detection sensor 502 is an external device. Is used for detecting the hue of the external light emitted from the first and second colors and correcting the output value of the first color detection sensor 102 based on the hue of the external light, as will be described later.

Further, this ultraviolet ray detection apparatus has a microcomputer 700 that receives output values from the first and second color detection sensors 102 and 502. The microcomputer 700 includes a memory 701, a comparison unit 702, a change amount calculation unit 703, and an ultraviolet ray amount calculation unit 704. The comparison unit 702, the change amount calculation unit 703, and the ultraviolet ray amount calculation unit 704 are configured by software by performing comparison and calculation as described later.

In the ultraviolet detection device having the above-described configuration, as shown in FIGS. 5 and 6A and 6B, external visible light 404 having no external ultraviolet light and a large amount of red component is converted into the color changing layer 401 and the visible light transmitting layer. Suppose that 501 is irradiated.

Then, the second color detection sensor 502 receives the transmitted light 505 having a large amount of red component derived from the external visible light 404 having a relatively large amount of red component from the visible light transmitting layer 501 and outputs the output shown in FIG. As shown in the waveform, the output values of the red component R502, the green component G502, and the blue component B502 are output. As can be seen from FIG. 6B, the output of the second color detection sensor 502 has a large amount of red component R502 and a small amount of green component G502 and blue component B502 because the external visible light 404 has a large amount of red component.

On the other hand, since the discoloration layer 401 is not receiving ultraviolet rays, it remains red. The first color detection sensor 102 receives the transmitted light 405 from the red color changing layer 401 and, as shown in the output waveform of FIG. 6A, the red component R102, the green component G102, and the blue component B102. Output the output value of. Since the color changing layer 401 is not receiving ultraviolet rays and is red, the red color changing layer 401 attenuates the light of the green component and the blue component, and the output waveforms shown in FIGS. As can be seen, the green component G102 and the blue component B102 of the output of the first color detection sensor 102 are lower than the non-attenuated green component G502 and the blue component B502 of the output of the second color detection sensor 502. On the other hand, since the red component light of the external visible light 404 can pass through the red color changing layer 401, the red component in the transmitted light 405 from the red color changing layer 401 is less attenuated and the first color detection sensor 102. The output value of the red color component R102 is substantially equal to the output value of the red color component R502 of the second color detection sensor 502. That is, as shown in FIGS. 6A and 6B, in the output waveforms of the first and second color detection sensors 102 and 502, the red component R102R≈the red component R502. Therefore, by comparing the red components R102 and R502 of the first color detection sensor 102 and the second color detection sensor 502, it is possible to detect the presence or amount of ultraviolet rays.

The microcomputer 700 determines the presence or absence of ultraviolet rays or calculates the amount as follows. Here, for convenience of explanation and simplicity, it is assumed that the external visible light 404, 604 has a large amount of red component.

First, the comparison means 702 of the microcomputer 700 determines whether or not the output value of the red component R502 of the second color detection sensor 502 is larger than a predetermined value, and the external visible light 404, 604 is determined. Confirm that there are many red components.

Next, the comparison unit 702 compares the output value of the red component of the first color detection sensor 102 with the output value of the red component of the second color detection sensor 502, and FIG. ), If it is equal, that is, if it is determined that the difference between the two output values is smaller than a predetermined value, an electrical signal indicating that there is no ultraviolet light is output. Here, it is assumed that there are many red components of the external visible light 404 and 604, but if not, R (red) of the first and second color detection sensors 102 and 502, depending on the color of the many components, The same determination can be made by selecting or appropriately combining the output components of G (green) and B (blue).

On the other hand, the comparison unit 702 compares the output value of the red component of the first color detection sensor 102 with the output value of the red component of the second color detection sensor 502, and FIG. If it is determined that there is a difference equal to or greater than a predetermined value that is not equal, an electrical signal indicating that there is ultraviolet light is output.

In the above description, the output values of the red component of the first and second color detection sensors 102 and 502 are compared. As can be seen from FIGS. 6 (A) and 6 (B) and FIGS. 8 (A) and 8 (B). As the amount of the external ultraviolet rays 603 increases, the red color component R102 of the first color detection sensor 102 decreases and the green color component G102 increases, while the color components of the second color detection sensor 502 become visible. Since the light transmission layer 501 is not discolored by ultraviolet rays, it does not matter whether ultraviolet rays are present. Therefore, the output values of the red component R102 and the green component G102 of the first color detection sensor 102 and the output values of the red component R502 and the green component G502 of the second color detection sensor 502 are compared twice, and the accuracy You may make it raise.

Next, the change amount calculation means 703 causes the red color component change amount, which is the difference between the red color component R502 of the second color detection sensor 502 and the red color component R102 of the first color detection sensor 102, and the second color detection. A green component change amount that is a difference between the green component G502 of the sensor 502 and the green component G102 of the first color detection sensor 102 is calculated. That is, the change amount calculating means 703
Red component change amount = R502-R102,
Green component change amount = G502-G102
Is calculated.

As can be seen from FIGS. 6A and 6B and FIGS. 8A and 8B, as the amount of the external ultraviolet ray 603 increases, the red component R102 of the first color detection sensor 102 decreases. While the green component G102 increases, the component of each color of the output of the second color detection sensor 502 is not affected by the amount of the external ultraviolet ray 603 because the visible light transmission layer 501 is not changed by the ultraviolet ray, and the red component changes. The combination of the amount (= R502-R102) and the green component change amount (= G502-G102) has a one-to-one relationship with the ultraviolet ray amount. An equation or table (determined from experimental data) that associates the red component variation amount and the green component variation amount with the ultraviolet ray amount on a one-to-one basis is stored in the memory 701 in advance.

The ultraviolet ray amount calculating means 704 calculates the ultraviolet ray amount by the above formula or referring to a table based on the calculated red component change amount and green component change amount, and electronic information representing the ultraviolet ray amount. Is output.

Thus, the second color detection sensor 502 detects the hue of the external visible light 404 and 604 that passes through the visible light transmission layer 501, and the hue of the external visible light 404 and 604 and the hue of the color changing layer 401 Thus, by calculating the amount of ultraviolet rays, the amount of ultraviolet rays can be accurately calculated without being affected by the hue of the external visible light 404 and 604 irradiated from the outside.

More specifically, as shown in FIG. 7, when the external ultraviolet ray 603 is irradiated, the discoloration layer 401 becomes green, the green component G102 of the output of the first color detection sensor 102 is large, and the red component R102. Decrease. If (green component G102 of the first color detection sensor 102) ≈ (green component G502 of the second color detection sensor 502), it represents the maximum light receiving state of the ultraviolet rays in the discoloration layer 401.

Here, the case where the color changing layer 401 changes from red to green according to the increase in the amount of the external ultraviolet rays 603 has been described. However, the color changing from one color to another color is performed using another color changing layer. However, the same is possible.

As described above, the ultraviolet detection device according to the second embodiment includes the first color detection sensor 102 that detects the hue of the discoloration layer 401, and the second color detection sensor 502 that detects the hue of the external visible light 404 and 604. Therefore, the output value of the first color detection sensor 102 is corrected by the output value of the second color detection sensor 502, so that the color change is not affected by the change in the hue of the external incident light. The amount of change in hue due to the ultraviolet rays unique to the layer 401 is calculated, and the amount of ultraviolet rays can be accurately obtained as electronic information.

In the ultraviolet detection device according to the second embodiment, since the first color detection sensor 102 detects the hue of the discoloration layer 401 that changes color due to ultraviolet rays, there is no need to add an electronic component such as a light emitting element as a light source. Therefore, it has the advantage of being small, compact and inexpensive.

In particular, when the ultraviolet detection device according to the second embodiment is mounted on an electronic device such as a mobile phone or a portable information terminal having a function for a health environment, there is an advantage that the mounting area is small.

In addition, the ultraviolet detection device according to the second embodiment does not directly measure the amount of ultraviolet rays, but detects the hue of the discoloration layer 401 that changes color according to the amount of ultraviolet rays by the first color detection sensor 102. An inexpensive general-purpose silicon photodiode can be used for the first color detection sensor 102, which has the advantage of being inexpensive.

In the second embodiment, the visible light transmission layer 501 is provided to protect the second color detection sensor 502 from ultraviolet rays, but the visible light transmission layer 501 is not always necessary.

(Third embodiment)
The ultraviolet detection device of the third embodiment includes a microcomputer 710 shown in FIG. 9, and the other configuration is the same as that of the second embodiment shown in FIGS. Therefore, about these other structures, FIGS. 5-8 is used and detailed description is abbreviate | omitted.

In the third embodiment, as shown in FIG. 9, the microcomputer 710 includes a memory 701, a comparison unit 702, a change amount calculation unit 703, an ultraviolet ray amount calculation unit 704, an illuminance detection unit 705, and a coefficient correction. Means 706. The configurations and functions of the memory 701, the comparison unit 702, the change amount calculation unit 703, and the ultraviolet ray amount calculation unit 704 are the same as those in the second embodiment, and the configurations and functions of the illuminance detection unit 705 and the coefficient correction unit 706 are the same. Only differs from the second embodiment.

The illuminance detection means 705 calculates the illuminance of the external visible light 404 and 604 as follows. That is, the illuminance detection means 705 outputs the output values (R, G, B) representing the respective light amounts of the red component R502, green component G502, and blue component B502 of the external visible light 404, 604 from the second color detection sensor 502. If you receive)
Illuminance = α × R + β × G + γ × B (α, β, γ are coefficients)
The illuminance is calculated and stored in the memory 701.

Thus, since the illuminance of the external visible light 404, 604 is calculated by the illuminance detection means 705, it is possible to determine whether the external illuminance is weak or strong.

Generally, offices, department stores, etc. are about 400 to 1000 lux, and the illuminance is about 100,000 lux in sunny daylight. From this, the range of the illuminance when it is necessary to check the amount of ultraviolet rays is limited (1000 lux or more 1 hour before the sunset), and if it is 300 lux or less, it can be determined that there is almost no ultraviolet rays.

Therefore, the color of the color changing layer 401 when the illuminance calculated by the illuminance detecting means 705 is 300 lux or less is the color of the color changing layer 401 in the absence of ultraviolet rays.

On the other hand, the color of the discoloration layer 401 may be deteriorated due to secular change or the like, and the discoloration layer in which this color has deteriorated needs to be corrected in order to accurately detect the amount of ultraviolet rays.

In the third embodiment, the first color detection sensor 102 is caused to detect the hue of the discoloration layer 401 in a state where the illuminance is lower than a predetermined value and there is no ultraviolet ray. The coefficient correction unit 706 outputs the output value of the first color detection sensor 102 representing the hue of the color changing layer 401 in the absence of ultraviolet light from the initial value representing the hue when the color changing layer 401 is not deteriorated. The fluctuation amount is calculated, and the coefficient of the formula for calculating the ultraviolet ray amount of the change amount calculating means 703 is corrected so as to compensate for the fluctuation amount according to the magnitude of the fluctuation amount.

Therefore, the ultraviolet ray amount detection device according to the third embodiment accurately detects the ultraviolet ray amount as electronic information without being affected by a state change such as deterioration of the discoloration layer even if the discoloration layer 401 deteriorates due to secular change or the like. Obtainable.

In the third embodiment, since the color state of the discoloration layer 401 is confirmed and corrected at low illuminance, which is an environment with less ultraviolet rays, the absolute amount of ultraviolet rays can be detected with high accuracy.

It should be noted that instead of correcting the coefficient of the above formula, correction may be made by adding or subtracting a constant term or using a different formula according to the magnitude of the above fluctuation.

(Fourth embodiment)
FIG. 10 is a perspective view of a portable information terminal as an example of an electronic apparatus according to the fourth embodiment of the present invention. In the fourth embodiment, the same components as those of the second embodiment shown in FIGS. 5 to 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

This portable information terminal includes a casing 801 and a top panel 802, and first and second color detection sensors 102 and 502 are provided in the casing 801.

A portion that functions as a window of the top panel 802 that faces the first and second color detection sensors 102 and 502 is provided with a color changing layer 401 and a visible light transmitting layer 501. The discoloration layer 401 faces the first color detection sensor 102 and partitions the inside and outside of the housing 801.

The color changing layer 401 changes color according to the amount of ultraviolet light of the external light 600, and the first color detection sensor 102 detects the color of the color changing layer 401 via the transmitted light 601. The second color detection sensor 502 detects the hue of the external light 600 via the transmitted light 602 that has passed through the visible light transmission layer 501.

The casing 801 is made of a material that does not transmit ultraviolet rays, and the top panel 802 also does not transmit ultraviolet rays. Further, the discoloration layer 401 and the visible light transmission layer 501 also have a property of hardly transmitting ultraviolet rays.

Therefore, the first and second color detection sensors 102 and 502 and other electronic components are shielded from ultraviolet rays and protected by the casing 801, the top panel 802, the color changing layer 401 and the visible light transmitting layer 501. Therefore, damage and failure are prevented.

(Fifth embodiment)
FIG. 11 is a block diagram of an ultraviolet detection device according to a fifth embodiment of the present invention.

As shown in FIG. 11, this ultraviolet ray detection device is provided with first and second color detection sensors 911 and 912 in proximity to each other on a silicon substrate 900. The first color detection sensor 911 has a red, green, and blue filter R, G, and B, and is a first RGB sensor photodiode array that includes a photo diode that detects red light, green light, and blue light. The second color detection sensor 912 has a red, green and blue filters R, G and B, and is a second RGB sensor comprising a photo dye auto for detecting red light, green light and blue light. This is a photodiode array.

On the first RGB sensor photodiode array 911, a color changing layer 901 that changes color according to the amount of ultraviolet rays is provided.

As described above, the first and second color detection sensors (first and second RGB sensor photodiode arrays) 911 and 912 are arranged close to each other on one silicon substrate 900. Since both are placed in the same state, the accuracy of correction by the output value of the second color detection sensor 912 with respect to the output value of the first color detection sensor 911 is increased, and the accuracy of detection of the amount of ultraviolet light is increased. Yes.

Further, separately from the first RGB sensor photodiode array 911 and the second RGB sensor photodiode array 912, photodiodes IR, IR for detecting infrared light are arranged in the vicinity of the first RGB sensor photodiode array 912, and infrared rays are arranged. A photocurrent generated by light is detected. Then, by removing the output value of the photodiode IR that detects infrared light from the output values of R, G, and B from the photo diode auto of the first and second RGB sensor photodiode arrays 911 and 912, ultraviolet rays are obtained. The amount can be detected with higher accuracy.

In general, sunlight or the like contains many infrared components in addition to ultraviolet rays, and when a photodiode receives infrared rays, as shown in FIG. 11, carriers 950 generated by infrared rays also become photocurrents, and R, G , B output. When an infrared cut layer can be placed on the top panel of a portable information terminal, the influence of infrared rays is reduced because infrared rays rarely enter the first and second color detection sensors, but an infrared cut layer is placed. If it is not possible, or if the infrared cut layer does not have sufficient characteristics, infrared light enters the first and second color detection sensors, and an error occurs. If the first color detection sensor and the second color detection sensor described above are separated at a large distance from each other, the irradiation amount of infrared rays is different, so that the correction accuracy is lowered. .

In the fifth embodiment shown in FIG. 11, the first color detection sensor 911 and the second color detection sensor 912 are adjacent to each other, and photodiodes IR and IR for infrared detection are provided, and the first and first color detection sensors 911 and 912 are provided. By removing output values generated by infrared light from the output values of R, G, and B of the second color detection sensors 911, 912, the amount of ultraviolet rays is detected with higher accuracy without being affected by the infrared light. be able to.

In the first to fifth embodiments, the hue of the color changing layer 101 is detected by the transmitted lights 105 and 205 from the color changing layer. However, the color of the color changing layer is detected by the reflected light from the color changing layer. You may make it do.

101, 401, 901 Discoloration layer 102, 911 First color detection sensor 501 Visible light transmission layer 502, 912 Second color detection sensor 801 Housing 802 Top panel

Claims

A color changing layer (101, 401, 901) that changes color according to the amount of ultraviolet rays received from the outside;
A first color detection sensor (102, 911) for detecting the color of the discoloration layer (101, 401, 901),
An ultraviolet ray detection apparatus, wherein the presence or absence of ultraviolet rays or the amount of ultraviolet rays is detected based on the hue of the discoloration layer (101, 401, 901) detected by the first color detection sensor (102, 911).
The ultraviolet detection device according to claim 1,
The discoloration layer (101, 401, 901) transmits external visible light, and the first color detection sensor (102, 911) detects the color of the transmitted light of the discoloration layer (101, 401, 901). An ultraviolet detecting device for detecting the presence or absence of ultraviolet rays or the amount of ultraviolet rays based on the color of the transmitted light corresponding to the color of the discoloration layer (101, 401, 901).
In the ultraviolet detection device according to claim 1 or 2,
A second color detection sensor (502, 912) for detecting the color of external visible light received from the outside;
Based on the output value of the second color detection sensor (502, 912) corresponding to the hue of external visible light, the first color detection sensor (102, 102) corresponding to the hue of the discoloration layer (101, 401, 901) is obtained. 911) is corrected.
In the ultraviolet detection device according to claim 3,
The first and second color detection sensors (102, 911, 502, 912) are RGB color sensors that detect the amount of red light, green light, and blue light,
The red (R), green (G), and blue (B) output values output by the first color detection sensor (102, 911) are output by the second color detection sensor (502, 912). An ultraviolet ray detection apparatus, wherein correction is performed based on output values of (R), green (G), and blue (B).
In the ultraviolet detection device according to claim 3 or 4,
Illuminance detection means (705) for detecting the illuminance of external visible light is provided,
The first color detection sensor (102, 911) of the output value of the first color detection sensor (102, 911) when the illuminance detected by the illuminance detection means (705) is lower than a predetermined value. An ultraviolet ray detecting device that corrects the calculation of the amount of ultraviolet rays based on a variation from the initial value of the.
In the ultraviolet detection device according to any one of claims 1 to 5,
A housing (801) is provided,
A first color detection sensor (102) is provided in the housing (801),
The ultraviolet detection device, wherein the discoloration layer (401) partitions the inside (outside) of the housing (801) to protect the first color detection sensor (102) from ultraviolet rays.
In the ultraviolet detection device according to any one of claims 3 to 5,
The first and second color detection sensors (102, 911, 502, 912) have red, green, and blue filters, respectively.
The ultraviolet detection device, wherein the red, green and blue filters are formed on the same silicon substrate (900) and arranged adjacent to each other.
An electronic apparatus comprising the ultraviolet sensor according to any one of claims 1 to 7.