Illumination sensor with spectral sensitivity corresponding to human luminosity characteristic

• US 6,670,597 B1
• Filed: 05/30/2000
• Issued: 12/30/2003
• Est. Priority Date: 08/06/1999
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Murata, Yukihiro, Akinari, Yoshinori, Kitamura, Nobuhiro, Ishigami, Yoshihisa
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US09/580,573
• Time in Patent Office: 1,309 Days
• Field of Search: 250/214.AL, 250/214.SW, 324/514, 315/149-155, 315/159
• US Class Current: 250/214.0AL
• CPC Class Codes: H03K 17/941 using an optical detector H03K17/968 takes precedence
• CPC Class Codes: H05B 41/2853 against abnormal power supply conditions
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A solar battery SB for detecting the surrounding brightness is provided and a switching element SW is controlled based on output voltage of the solar battery SB. The switching element SW is made up of MOSFETs Q1 and Q2. To form an electronic automatic on/off switch, a triac Q is controlled by turning on/off the switching element SW.

Claims

1. An illumination sensor comprising:

a photovoltaic element defined by a solar battery for generating an output voltage responsive to brightness of ambient light;

a switching element defined by MOSFET turned on/off in response to the output voltage of said photovoltaic element for opening/closing a separately provided switch element; and

a light quantity adjustment member placed in at least a part of an incidence path of ambient light on a light reception face of said photovoltaic element and having transmittance controlled by an external signal generated in response to opening/closing the switch element.

2. The illumination sensor as claimed in claim 1 wherein said switching element is defined by two MOSFETs with sources connected and gates connected in common.

3. The illumination sensor as claimed in claim 1 wherein said photovoltaic element is a solar battery including a plurality of cells each having a pin structure connected in series on a single plane, and the cells are formed on a single substrate.

4. The illumination sensor as claimed in claim 1, further comprising:

a liquid crystal plate;

a polarizing plate placed on each of a front and a back of the liquid crystal plate, the transmittance of the polarizing plates and the liquid crystal plate being set based on the relative angle of a vibration face of light passing through the polarizing plates,

wherein the light quantity adjustment member has a transmittance-type liquid crystal plate having transmittance changed in response to the strength of an electric field applied to liquid crystal.

5. The illumination sensor as claimed in claim 1, wherein a monocrystalline silicon solar battery having a sensitivity wavelength range across a visible light area and a near-infrared light area and a peak wavelength in an infrared light area is used as said photovoltaic element the light quantity adjustment member has a transmittance-type liquid crystal plate having transmittance changed in response to the strength of an electric field applied to liquid crystal, and

wherein the liquid crystal plate used has a transmittance characteristic different between the visible light area and the infrared light area.

6. The illumination sensor as claimed in claim 1, further comprising:

a filter having transmittance different in a visible light area and an infrared light area added to the incidence path of ambient light on the light reception face of said photovoltaic element.

7. The illumination sensor as claimed in claim 1 further comprising:

a control circuit inserted between said photovoltaic element and said switching element for adjusting a response of said switching element to change in the output voltage of said photovoltaic element.

8. The illumination sensor as claimed in claim 1, further comprising:

a print-circuit board formed with a wiring pattern for surface-mounting electric parts and provided with connection terminals for connecting to an external circuit and a package made of a translucent synthetic resin, integral with the print-circuit board so as to cover the side of the print-circuit board on which said photovoltaic element is mounted.

9. The illumination sensor as claimed in claim 1 further comprising:

a package made of a molded article of a synthetic resin, the package formed with connection terminals for connecting to an external circuit in one piece.

10. The illumination sensor as claimed in claim 9, wherein the package is a MID formed with parts mounting parts for mounting electric parts and wiring parts forming electric paths between the parts mounting parts and the connection terminals by metal plating.

11. The illumination sensor as claimed in claim 9, wherein the package is molded with a metal frame in one piece at the same time, the frame being formed with parts mounting parts where the connection terminals and electric parts are mounted and wiring parts forming electric paths between the connection terminals and the parts mounting parts.

12. The illumination sensor as claimed in claim 11, further comprising:

a first seal member having a translucent property for sealing said photovoltaic element and a second seal member having a lightproof property for sealing said switching element.

13. The illumination sensor as claimed in claim 11, wherein the package is provided with a separation wall for separating the mounting part of said switching element and the mounting part of said photovoltaic element, and

wherein a first seal member having a lightproof property for sealing said switching element and a second seal member having a translucent property for sealing said photovoltaic element are separated through the separation wall.

14. The illumination sensor as claimed in claim 11, wherein the light quantity adjustment member is attached to the package so as to overlap at least a part of a light reception face of said photovoltaic element and is mounted on the parts mounting part and is electrically connected to the connection terminal.

15. The illumination sensor as claimed in claim 14, wherein the light quantity adjustment member has a transmittance-type liquid crystal plate having transmittance changed in response to the strength of an electric field applied to liquid crystal and includes a translucent seal member for sealing at least the periphery on the incidence side of ambient light on the liquid crystal plate.

16. The illumination sensor as claimed in claim 14, wherein the light quantity adjustment member has a filter having a spectral transmittance characteristic different from that of said photovoltaic element, and the filter is attached to the package so as to be opposed to the light reception face of said photovoltaic element.