JP2006148572A - Light receiver and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a light receiver capable of effectively reducing malfunction and deterioration of an SN ratio due to the influence of an inverter fluorescent light without increasing a circuit scale and an electronic apparatus provided with the light receiver. <P>SOLUTION: The light receiver 11 is provided with a PD 1 and a PD 2 respectively prepared as a first light receiver and a second light receiver, and has circuit constitution for subtracting the output of the PD2 from the output of the PD1. In the receiver, the PD1 is provided with a band-pass optical filter, and the PD2 is provided with a band interruption type optical filter. Since the optical filter is formed on the surface of a light receiving element (photodiode) as an optical thin film, the optical thin film can be easily formed by a conventional integrated circuit (IC) manufacturing process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light receiving device for optical space transmission and an electronic device using the same, such as an infrared remote control receiver.

  The transmission signal of the infrared remote control receiver is generally an ASK (Amplitude Shift Keying) signal modulated with a predetermined carrier of about 30 kHz to 60 kHz, and the receiving chip amplifies the input photocurrent signal with an amplifier, The carrier component is extracted by a band pass filter (BPF) that matches the carrier frequency, the carrier is detected by the detection circuit, the time in which the carrier is present is integrated by the integration circuit, the presence / absence of the carrier is determined by the hysteresis comparator, and digital output is performed. .

  In addition, since the household inverter fluorescent lamp has a carrier component of 30 kHz to 60 kHz, when the inverter fluorescent lamp exists around the infrared remote control receiver, the inverter fluorescent lamp noise component is detected and malfunctions, or in the worst case There is a problem that the transmission signal cannot be received correctly. In general, since the output of the infrared remote control receiver is input to the interrupt port of the microcomputer, the microcomputer does not enter the sleep (energy saving) mode in a situation where a malfunction occurs due to the inverter fluorescent lamp.

  Here, the wavelength of the inverter fluorescent lamp has a peak in the visible region of 500 nm to the infrared of about 1000 nm, and the transmission signal of the infrared remote controller uses the vicinity of 940 nm. Therefore, it is effective to improve the spectral sensitivity characteristics and increase the S / N ratio by using the wavelength selective optical filter. However, the wavelength selective optical filter is generally expensive and is not suitable for inexpensive equipment such as an infrared remote control receiver.

  Here, an effective light receiving method and circuit method for satisfying the above requirements will be described.

  FIG. 12 shows an example of an infrared remote control receiver as Conventional Example 1. That is, the light receiving circuit unit 101 includes a PD 1 and an IC (integrated circuit) 23 as a signal processing circuit. HA41, D_HA42, and 2ndAmp43 correspond to the first to third amplifiers 15 to 17, respectively. The output of 2nd Amp 43 controlled by an AGC (auto gain control) circuit 47 is input to 3rd Amp 44, input to the BPF 45 under the control of the fo trimming circuit 46, and output through the carrier detection circuit 48, the integration circuit 49, and the hysteresis comparator 50. It is like that.

  Here, the spectral sensitivity characteristic of PD1 (photodiode) has a peak around 940 nm, and a special wavelength selective optical filter or the like is not used.

  In this case, there are problems such as malfunction due to inverter fluorescent lamp noise and the inability to correctly receive transmission signals. Although BPF is built in the integrated circuit to reduce inverter fluorescent lamp noise, it is not sufficient.

  FIG. 13 shows a configuration described in JP-A-8-330621 as Conventional Example 2. Phototransistors PT1 and PT2 are used, and an optical filter 124 is attached to PT1. And the light of a specific wavelength is detected by detecting the difference in spectral sensitivity using an optical filter.

  In this method, since the peak wavelength of the sensitivity of the light receiving element does not match the wavelength of the signal to be detected, the detection sensitivity is significantly reduced. Moreover, since an optical filter is expensive, it cannot be easily used for an inexpensive system.

  FIG. 14 shows spectral sensitivity characteristics in the configuration described in Japanese Patent Laid-Open No. 7-38501 as Conventional Example 3. In the figure, A is the spectral sensitivity characteristic of the photodiode, and B is the spectral sensitivity characteristic of the visible light cut filter. By using the visible light cut filter, the inverter fluorescent lamp noise is reduced and the SN ratio (signal to noise ratio) is improved.

  Also in this case, the optical filter is expensive and cannot be easily used for an inexpensive system.

  FIG. 15 shows a configuration described in Japanese Patent Laid-Open No. 9-46772 as Conventional Example 4. A signal having a specific wavelength is detected using photodiodes PDa and PDb having different spectral sensitivities, subtracted by a subtracting circuit 141, and output from the current compression circuit 142. One photodiode PDa has high spectral sensitivity with respect to a specific wavelength, and the other photodiode PDb has spectral sensitivity over a wavelength range wider than this specific wavelength.

  In this case, the light receiving element on the subtraction side has sensitivity with respect to the specific wavelength. Therefore, subtraction reduces the sensitivity of the signal component.

  FIG. 16 shows a configuration described in Japanese Patent Laid-Open No. 5-260573 as Conventional Example 5. The photodiode PDc has a spectral sensitivity with respect to the signal wavelength, and the photodiode PDd has a spectral sensitivity at a wavelength distant from the signal wavelength. These outputs are processed by two systems of BPF 151 and 153 and detection circuits 152 and 154, respectively, and subtracted by a subtraction processing circuit 156 and output. Using light receiving elements that are sensitive to light of different wavelengths, the inverter fluorescent lamp noise is reduced and the SN ratio is improved.

In this case, there is a problem that the BPF is also required on the subtracting side and the circuit scale increases.
JP-A-8-330621 (Publication date: December 13, 1996) Japanese Patent Laid-Open No. 7-38501 (Publication date: February 7, 1995) JP 9-46772 A (publication date February 14, 1997) JP-A-5-260573 (publication date: October 8, 1993)

  As described above, the conventional configuration has problems such as malfunction due to the influence of the inverter fluorescent lamp, degradation of the SN ratio, and increase in circuit scale.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a light receiving device that can effectively reduce malfunction and SN ratio deterioration due to the influence of an inverter fluorescent lamp without increasing the circuit scale. The realization of electronic equipment.

  In order to solve the above problems, a light receiving device according to the present invention includes a first light receiving unit having a spectral sensitivity peak in a wavelength range used for communication in a light receiving device that receives a communication signal of light at a light receiving unit, Except for having no spectral sensitivity in the wavelength range used for communication, the second light receiving unit having the same or approximate spectral sensitivity characteristic as the second light receiving unit, the detection output of the first light receiving unit, and the detection of the second light receiving unit And a subtracting unit that performs a subtraction process on the output.

  With the above configuration, in the wavelength range used for optical communication such as infrared communication, the value of the spectral sensitivity characteristic on the second light receiving unit side is much smaller than the value of the spectral sensitivity characteristic on the first light receiving unit side. In this case, the value on the first light receiving unit side remains large. On the other hand, in the other wavelength ranges, the value on the first light receiving unit side and the value on the second light receiving unit side are the same or substantially equal, and therefore the remaining in the subtraction process is zero or slight. That is, the signal is large in the wavelength range used for communication, and the signal is small in the other wavelength ranges.

  As a result, malfunction due to the influence of the inverter fluorescent lamp and deterioration of the SN ratio can be effectively reduced.

  In addition, since the BPF is not required for both of the two systems, the circuit scale does not increase.

  Therefore, it is possible to effectively reduce malfunction and SN ratio degradation due to the influence of the inverter fluorescent lamp without increasing the circuit scale.

  Further, in the light receiving device according to the present invention, in addition to the above configuration, the second light receiving unit is provided with a band cutoff optical filter that blocks transmission of a wavelength band used for communication, to the first light receiving unit. It is characterized by becoming.

  With the above configuration, the second light receiving unit can be obtained by attaching a band cutoff optical filter that blocks a wavelength band used for communication to the light receiving element. Therefore, in addition to the effect of the above configuration, the configuration of the second light receiving unit can be obtained at low cost.

  In addition to the above configuration, the light receiving device according to the present invention is characterized in that the first light receiving unit includes a light-receiving element provided with a band-pass optical filter that transmits a wavelength band used for communication. Yes.

  With the above configuration, the first light receiving unit can be obtained by attaching a band-pass optical filter that transmits a wavelength band used for communication to the light receiving element. Therefore, in addition to the effect of the above configuration, the configuration of the first light receiving unit can be obtained at low cost.

  In addition to the above configuration, when the wavelength of light used for communication is λ, the band-blocking optical filter has an optical path length that is an odd multiple of λ / 2. It is characterized by being formed of a thin film.

  With the above configuration, the band cutoff optical filter is formed of an optical thin film whose optical path length is an odd multiple of λ / 2. Therefore, in addition to the effect by the above configuration, there is an effect that the band cutoff optical filter can be formed with a simple configuration.

  In addition to the above configuration, the light-receiving device according to the present invention has an optical path length that is an even multiple of λ / 2 when the wavelength of light used for communication is λ. It is characterized by being formed of a thin film.

  With the above configuration, the band-pass optical filter is formed of an optical thin film whose optical path length is an even multiple of λ / 2. Therefore, in addition to the effect by the above configuration, there is an effect that the band cutoff optical filter can be formed with a simple configuration.

  In addition to the above configuration, the light receiving device according to the present invention is characterized in that a plurality of optical thin films are laminated.

  With the above configuration, a plurality of the optical thin films are laminated. Therefore, in addition to the effect by the above configuration, there is an effect that it is possible to easily form an optical filter having various passing / shutoff specifications for each wavelength.

  In addition to the above configuration, the light receiving device according to the present invention is characterized in that the optical thin film is formed of a silicon nitride film.

  With the above configuration, the optical thin film is formed of a silicon nitride film. Therefore, in addition to the effects of the above configuration, a general integrated circuit manufacturing process can be used, and an optical filter can be formed at low cost.

  In addition to the above configuration, the light receiving device according to the present invention is characterized in that the optical thin film is formed of a polysilicon film.

  With the above configuration, the optical thin film is formed of a polysilicon film. Therefore, in addition to the effects of the above configuration, a general integrated circuit manufacturing process can be used, and an optical filter can be formed at low cost.

  In addition to the above configuration, the light receiving device according to the present invention is characterized in that the plurality of first light receiving units and the plurality of second light receiving units are arranged point-symmetrically.

  With the above configuration, the plurality of first light receiving units and the plurality of second light receiving units are arranged point-symmetrically. Therefore, in addition to the effect of the above configuration, since the signal light and the noise light are uniformly incident on the first light receiving unit and the second light receiving unit, it is possible to more effectively remove the noise light component. Play.

  According to another aspect of the present invention, there is provided an electronic apparatus including any one of the light receiving devices described above.

  With the above configuration, the electronic apparatus includes any one of the light receiving devices described above. Therefore, in the wavelength range used for optical communication such as infrared communication, the value of the spectral sensitivity characteristic on the second light receiving unit side is much smaller than the value of the spectral sensitivity characteristic on the first light receiving unit side. 1 The value on the light receiving side remains large. On the other hand, in the other wavelength ranges, the value on the first light receiving unit side and the value on the second light receiving unit side are the same or substantially equal, and therefore the remaining in the subtraction process is zero or slight. That is, the signal is large in the wavelength range used for communication, and the signal is small in the other wavelength ranges.

  As a result, malfunction due to the influence of the inverter fluorescent lamp and deterioration of the SN ratio can be effectively reduced.

  In addition, since the BPF is not required for both of the two systems, the circuit scale does not increase.

  Therefore, it is possible to effectively reduce malfunction and SN ratio degradation due to the influence of the inverter fluorescent lamp without increasing the circuit scale.

  As described above, the light receiving device according to the present invention has a spectral sensitivity characteristic except that the first light receiving unit has a spectral sensitivity peak in the wavelength range used for communication and does not have spectral sensitivity in the wavelength range used for communication. The second light receiving unit is the same as or similar to the second light receiving unit, and a subtracting unit that subtracts the detection output of the first light receiving unit and the detection output of the second light receiving unit.

  An electronic apparatus according to the present invention includes any one of the light receiving devices described above.

  As a result, it is possible to effectively reduce malfunction and SN ratio deterioration due to the influence of the inverter fluorescent lamp without increasing the circuit scale.

  FIG. 1 shows a circuit configuration of the light receiving device. FIG. 2 shows an actual circuit diagram. A light receiving element PD1 or PD1 that is a photodiode and an optical filter described later form a first light receiving portion. In addition, a second light receiving portion is formed by the light receiving element PD2 which is a photodiode and an optical filter which will be described later. The light receiving device 11 receives the transmission signal by the light receiving element PD1, amplifies it by the first amplifier 15 (amp1), and inputs it to the + (plus) side of the third amplifier (amp3).

  The light receiving element PD2 receives the noise component that blocks the light of the transmission signal, amplifies the same in amp2, and inputs it to the minus (−) side of amp3. The noise component can be effectively removed by subtracting V (PD2) from V (PD1) at amp3.

  The noise component can be effectively removed by adjusting the spectral sensitivity of the light receiving element.

  FIG. 3 shows an example of a main part of the infrared remote control receiver (electronic device) of the present embodiment. That is, the light receiving circuit unit 31 includes PD1 and PD2 and an IC (integrated circuit) 23 as a signal processing circuit. HA41, D_HA42, and 2ndAmp43 correspond to the first to third amplifiers 15 to 17, respectively. The output of 2nd Amp 43 controlled by an AGC (auto gain control) circuit 47 is input to 3rd Amp 44, input to the BPF 45 under the control of the fo trimming circuit 46, and output through the carrier detection circuit 48, the integration circuit 49, and the hysteresis comparator 50. It is like that.

  FIG. 4 shows an example of a module of the infrared remote control receiver. In the infrared remote control receiver 21, the PD unit 22 and the IC 23 are mounted on an aluminum frame 27, wire bonding is performed on an Au wire (gold wire) 26, and each element is electrically connected. Thereafter, the resin package (infrared transmitting resin) 25 is sealed. At this time, since the lens-shaped portion 25 a is formed on the upper portion of the PD portion 22 by the resin package 25, the light can be focused on the central portion of the PD portion 22.

  Further, in a configuration with four PDs, which will be described later, as a result of focusing as described above, the center of incident light hits the center of point symmetry.

[About optical filters]
As shown in FIG. 7, the PD section 22 (PD2 and / or PD1) is provided with an optical filter composed of an optical thin film 24 formed on the PD surface. As the optical filter, a band cutoff optical filter or a band pass optical filter is used depending on the situation. here,
n0: refractive index of medium 0 (in the case of air≈1),
n0: refractive index of medium 1,
d: film thickness of the optical thin film 24,
λ: wavelength of transmitted signal,
m: integers 0, 1, 2, 3,..., and assuming that the signal light is incident perpendicular to the light receiving surface, due to interference of the optical thin film 24,
When the optical path length is an odd multiple of λ / 2 [2 × (n1 / n0) × d = λ / 2 × (2m + 1)]: reflection (band cutoff optical filter)
When the optical path length is an even multiple of λ / 2 [2 × (n1 / n0) × d = λ / 2 × (2m)]: Absorption (band-pass optical filter)
Such a phenomenon occurs. Therefore, an arbitrary optical filter can be formed by adjusting the film thickness of the optical thin film 24 with respect to the wavelength of the transmission signal.

  In this way, the first light receiving unit can be obtained by attaching the band-transmitting optical filter that transmits the wavelength band used for communication to the light receiving element, and the second light receiving unit is connected to the light receiving element by communication. It can be obtained by attaching a band cut-off optical filter that cuts off the wavelength range to be used.

  FIG. 5 shows an example of spectral sensitivity characteristics when no optical filter is attached to PD1 and a band-cut optical filter is attached to PD2. FIG. 6 shows an example of spectral sensitivity characteristics when a band-pass optical filter is attached to PD1 and a band-cut optical filter is attached to PD2. The large spectral sensitivity characteristic means that the output, that is, the amount of light transmitted (passed) is large. 5 and 6 are relative values assuming that the output when all the light is transmitted is 100%.

  In the wavelength range used for optical communication such as infrared communication, the value of the spectral sensitivity characteristic on the PD2 side is much smaller than the value of the spectral sensitivity characteristic on the PD1 side, so that the value on the PD1 side remains large in the subtraction process. On the other hand, in the other wavelength ranges, the value on the PD1 side and the value on the PD2 side are equal or nearly equal, and therefore, the remainder is zero or slight in the subtraction process. That is, the signal is large in the wavelength range used for communication, and the signal is small in the other wavelength ranges. As a result, malfunction due to the influence of the inverter fluorescent lamp and deterioration of the SN ratio can be effectively reduced.

  At this time, in the integrated circuit manufacturing process, it is common to use a silicon nitride film or a polysilicon film when forming a capacitor. Since the optical thin film 24 can be formed by the same process, an optical filter is formed at a low cost. it can.

  As described above, in the present embodiment, the first light receiving unit and the second light receiving unit are provided, and the circuit configuration is such that the output of the second light receiving unit is subtracted from the output of the first light receiving unit. The band-pass optical filter is formed, and the second light receiving portion is formed by providing a band-blocking optical filter in the light receiving element. In this way, by forming the optical filter as an optical thin film on the surface of the light receiving element (photodiode), the optical thin film can be easily formed by a conventional integrated circuit (IC) manufacturing process.

  In addition, it is possible to increase the reflectance or the absorptance and improve the spectral sensitivity characteristics by making the optical thin film into a multilayer (by stacking media having different refractive indexes in a multilayer). FIG. 8 shows an example of a multilayer structure.

  In the multilayer thin film, an interference condition is required for each layer. Here, the optical thin film 24 is arranged in the order of distance from the PD section 22, the first layer (first thin film 24 a), the second layer (second thin film 24 b), the second layer (third thin film 24 c),. (I-th thin film) (i is an integer equal to or greater than 1). FIG. 8 shows an example of a three-layer structure.

In the first layer,
n0: refractive index of medium 0 (in the case of air≈1),
n1: Refractive index of medium 1
d1: film thickness of the optical thin film,
λ: wavelength of transmitted signal,
m1: When integers 0, 1, 2, 3,...
When the optical path length is an odd multiple of λ / 2 [2 × (n1 / n0) × d1 = λ / 2 × (2m1 + 1)]: reflection (band cutoff optical filter)
When the optical path length is an even multiple of λ / 2 [2 × (n1 / n0) × d1 = λ / 2 × (2m1)]: Absorption (band-pass optical filter)
It becomes.

In the second layer,
n1: Refractive index of medium 1 (in the case of air≈1),
n2: refractive index of medium 2,
d2: optical thin film thickness,
λ: wavelength of transmitted signal,
m2: When integers 0, 1, 2, 3,.
When the optical path length is an odd multiple of λ / 2 [2 × (n2 / n1) × d2 = λ / 2 × (2m2 + 1)]: reflection (band cutoff optical filter)
When the optical path length is an even multiple of λ / 2 [2 × (n2 / n1) × d2 = λ / 2 × (2m2)]: Absorption (bandpass optical filter)
It becomes.

In the third layer,
n2: Refractive index of medium 2 (in the case of air≈1),
n3: refractive index of medium 3;
d3: film thickness of the optical thin film,
λ: wavelength of transmitted signal,
m3: When integers 0, 1, 2, 3,...
When the optical path length is an odd multiple of λ / 2 [2 × (n3 / n2) × d3 = λ / 2 × (2m3 + 1)]: reflection (band cutoff optical filter)
When the optical path length is an even multiple of λ / 2 [2 × (n3 / n2) × d3 = λ / 2 × (2m3)]: Absorption (bandpass optical filter)
It becomes.

In general, in the i-th layer,
n (i-1): refractive index of medium (i-1) (in the case of air≈1),
ni: refractive index of medium i,
di: film thickness of the optical thin film,
λ: wavelength of transmitted signal,
mi: When integers 0, 1, 2, 3,...
When the optical path length is an odd multiple of λ / 2 [2 × (ni / n (i−1)) × di = λ / 2 × (2mi + 1)]: reflection (band cutoff optical filter)
When the optical path length is an even multiple of λ / 2 [2 × (ni / n (i−1)) × di = λ / 2 × (2mi)]: absorption (band-pass optical filter)
It becomes. For example, it is possible to adjust all layers to be reflective (blocking) layers, all layers to be absorbing (transmitting) layers, or to set each layer as a reflective layer / absorbing layer as appropriate. The rate can be suitably increased (or decreased).

[About PD placement]
As shown in FIG. 9, the first and second light receiving elements are arranged close to each other in a point-symmetric manner. These PD1 and PD2 are connected to other elements by bonding pads 22a.

  FIG. 10A shows a state where the lens spot 55 is not displaced from the point-symmetrical center, and FIG. 10B shows a state where the lens spot 55 is displaced from the point-symmetrical center. By arranging PD1 and PD2 symmetrically, the area irradiated on PD1 and PD2 can be kept constant even when the lens spot is irradiated from a shifted position. That is, the total area irradiated with the two PDs 1 is the same in FIG. 10A and FIG. 10B, and the total area irradiated with the two PDs 2 is the same as FIG. It is equal to 10 (b). Therefore, the output current is stabilized. FIG. 11 shows a connection state of the two PDs 1 and two PDs 2 in FIG. In the light receiving device 12, two PD1s are connected in parallel, and two PD2s are connected in parallel. The rest is the same as the configuration of FIG.

  With such a point-symmetric arrangement, the signal light and the noise light are uniformly incident on the first and second light receiving elements, so that the noise light component can be more effectively removed by the subsequent amp3 circuit. That is, by arranging PD1 and PD2 close to each other, there is an advantage that irradiation of signal light and noise light onto the PD becomes equal.

As described above, the present invention provides the following effects.
(1) By providing a first light receiving unit and a second light receiving unit and subtracting the output of the second light receiving element from the output of the first light receiving element, noise components can be effectively reduced with a small circuit scale. It can be removed.
(2) The noise component can be effectively removed by adjusting the spectral sensitivity characteristic of the light receiving element in the above (1).
(3) By forming an optical thin film on the surface of the light receiving element, a band cutoff optical filter and a band pass optical filter can be easily formed.
(4) In the above (3), it is possible to increase the reflectance or the absorptivity by making the optical thin film multilayer, and to make the spectral sensitivity characteristic steep.
(5) In the above (3) and (4), since the optical thin film is formed of SiN and Poly-Si, it can be formed by an integrated circuit manufacturing process, so that it can be manufactured at low cost.
(6) Since the first light receiving unit and the second light receiving unit are arranged close to each other in a point-symmetric manner, signal light and noise light are uniformly incident on the first light receiving unit and the second light receiving unit. The noise light component can be effectively removed.
(7) By using it for an infrared remote control receiver, it is possible to reduce malfunctions and improve the SN ratio due to the inverter fluorescent lamp.

  Note that although an infrared remote control receiver is shown here as an electronic device, the present invention is not limited to this, and any electronic device can be applied as long as it has a device for receiving an optical signal in optical communication such as infrared rays.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  The light receiving device according to the present invention includes first and second light receiving units having the same or approximate spectral sensitivity characteristics, and a subtracting unit that inputs and outputs the detection outputs of the two light receiving units. The second light receiving unit may be configured not to be sensitive to the peak region of the spectral sensitivity characteristic of the first light receiving unit.

  Moreover, the light receiving device according to the present invention may be configured such that, in the above configuration, the second light receiving unit is provided with a band cutoff optical filter on a surface of the light receiving element.

  In the light receiving device according to the present invention, in the above configuration, the first light receiving unit is provided with a band-pass optical filter on the surface of the light receiving element, and the second light receiving unit is provided on the surface of the light receiving element. A band cutoff optical filter may be provided.

  In the light receiving device according to the present invention, the band cut optical filter may be formed of an optical thin film whose optical path length is an odd multiple of λ / 2 (λ: wavelength of light). Good.

  In the light receiving device according to the present invention, in the above configuration, the bandpass optical filter is formed of an optical thin film having an optical path length that is an even multiple of λ / 2 (λ: wavelength of light). The filter may be formed of an optical thin film whose optical path length is an odd multiple of λ / 2 (λ: wavelength of light).

  Further, the light receiving device according to the present invention may be configured such that the optical thin film is multilayered in the above configuration.

  The light receiving device according to the present invention may be configured such that in the above configuration, the optical thin film is formed of a silicon nitride film.

  The light receiving device according to the present invention may be configured such that in the above configuration, the optical thin film is formed of a polysilicon film.

  Moreover, the light receiving device according to the present invention may be configured such that, in the above configuration, the first and second light receiving portions are divided light receiving elements arranged in a point symmetry.

  Moreover, you may comprise the electronic device which concerns on this invention using the light-receiving device as described in any one of said.

  The present invention can also be applied to applications such as an electronic device such as an infrared remote control receiver provided with a light receiving device for optical space transmission.

It is a circuit diagram which shows one structural example of the light-receiving device which concerns on this invention. It is a circuit diagram which shows one structural example of the light-receiving device which concerns on this invention. It is a block diagram which shows the principal part of the infrared remote control receiver using the light-receiving device of this invention. (A) And (b) shows the infrared remote control receiver which used the light-receiving device of this invention, (a) is a side view, (b) is a front view. It is a figure which shows the spectral sensitivity characteristic by the light-receiving device based on this invention. It is a figure which shows the spectral sensitivity characteristic by the light-receiving device based on this invention. It is a figure which shows the optical thin film which concerns on this invention. It is a figure which shows the optical thin film which concerns on this invention. It is a top view which shows division | segmentation PD based on this invention. (A) And (b) is a figure which shows a mode that it received with the division | segmentation PD of this invention, (a) is the case where the spot by a lens has not shifted, (b) is the case where the spot by a lens has shifted. FIG. It is a circuit diagram which shows one structural example of the light-receiving device based on this invention using division | segmentation PD. It is a block diagram which shows the structural example of the conventional infrared remote control receiver. It is a circuit diagram which shows the structural example of the conventional light-receiving device. It is a figure which shows the spectral sensitivity characteristic by the conventional light-receiving device. It is a block diagram which shows the structural example of the conventional light-receiving device. It is a block diagram which shows the structural example of the conventional light-receiving device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Light receiver 12 Light receiver 15 1st amplifier 16 2nd amplifier 17 3rd amplifier 21 Infrared remote control receiver (electronic device)
22 PD 22a Bonding pad 23 IC
24 Optical thin film 24a First thin film 24b Second thin film 24c Third thin film 25 Resin package 25a Lens shape part 26 Au wire 27 Aluminum frame 31 Light receiving circuit part 41 HA
42 D_HA
43 2ndAmp
44 3rdAmp
45 BPF
46 fo trimming circuit 47 AGC circuit 48 carrier detection circuit 49 integration circuit 50 hysteresis comparator 55 lens spot PD1, PD2 light receiving element

Claims (10)

In a light receiving device that receives a communication signal of light at a light receiving unit,
A first light receiving unit having a spectral sensitivity peak in a wavelength range used for communication;
A second light-receiving unit having a spectral sensitivity characteristic that is the same as or close to that of the second light-receiving unit, except that the wavelength region used for communication does not have spectral sensitivity;
A light receiving device, comprising: a subtracting unit that subtracts the detection output of the first light receiving unit and the detection output of the second light receiving unit.   2. The light receiving device according to claim 1, wherein the second light receiving unit includes a light receiving element provided with a band cutoff optical filter that blocks a wavelength band used for communication.   The light receiving device according to claim 2, wherein the first light receiving unit is formed by attaching a band-pass optical filter that transmits a wavelength band used for communication to the light receiving element.   The band-cut optical filter is formed of an optical thin film whose optical path length is an odd multiple of λ / 2 when the wavelength of light used in communication is λ. Light receiving device.   The bandpass optical filter is formed of an optical thin film having an optical path length that is an even multiple of λ / 2 when the wavelength of light used in communication is λ. Light receiving device.   6. The light receiving device according to claim 4, wherein a plurality of the optical thin films are laminated.   6. The light receiving device according to claim 4, wherein the optical thin film is formed of a silicon nitride film.   6. The light receiving device according to claim 4, wherein the optical thin film is formed of a polysilicon film.   The light receiving device according to claim 1, wherein the plurality of first light receiving units and the plurality of second light receiving units are arranged point-symmetrically. In an electronic device equipped with a light receiving device,
An electronic apparatus comprising the light receiving device according to claim 1.

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