Unlock instant, AI-driven research and patent intelligence for your innovation.

Brightness sensor

A technology of brightness sensor and current, which is applied in the direction of instruments, scientific instruments, photometry, etc., and can solve the problems that the illumination detection cannot be realized

Inactive Publication Date: 2005-08-31
MATSUSHITA ELECTRIC WORKS LTD
View PDF1 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, if a photoelectric conversion element is used to form a luminance sensor, the illuminance detection discrimination rate in the entire detectable illuminance range is the same, and it is impossible to use a CdS3 luminance sensor. The lower the illuminance, the higher the illuminance detection discrimination rate, which is close to the characteristics of human vision. , resulting in the problem that it is impossible to achieve illuminance detection in line with human visual characteristics

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Brightness sensor
  • Brightness sensor
  • Brightness sensor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0055] The luminance sensor of this embodiment is such as figure 1 , has a structure in which the photoelectric conversion element phototransistor PTr and the nonlinear element diode D1 are connected in series. This embodiment is like a luminance sensor using CdS described with a known structure, and a luminance sensor with a detectable illuminance range of 5-10000 Lx is used for illustration.

[0056] The series circuit of the phototransistor PTr and the diode D1 is composed of: the passing current through the series circuit is limited by the phototransistor PTr, and the emitter of the diode D1 phototransistor PTr is connected to the anode of the diode D1, so that the passing current flows in the forward direction of the diode D1 A DC voltage at which the collector of the phototransistor PTr becomes positive due to the DC current is applied between both ends. In this state, the voltage across the diode D1 is configured to be output as the detection voltage V0. When the pho...

Embodiment approach 2

[0064] The brightness sensor of this embodiment, such as Figure 7 , together with the phototransistor PTr constitutes a non-linear element of a series circuit, and a Zener diode ZD1 is used instead of a diode to connect the passing current to the reverse flow of the Zener diode ZD1, which is different from the brightness sensor of Embodiment 1. The voltage across the Zener diode ZD1 is output as a detection voltage V0. Here, a phototransistor PTr with a smaller passing current is selected relative to the illuminance of 10000Lx, so that when the illuminance reaches the maximum value of the detectable illuminance range, the passing current through the Zener diode ZD1 is still sufficiently low and the detection voltage V0 does not reach the Zener diode. Zener voltage of ZD1.

[0065] And the Zener diode ZD1 has, as the current (vertical axis) expressed in logarithm Figure 8 , the current passing through in the reverse direction is a low current and the voltage at both ends is...

Embodiment approach 3

[0073] The brightness sensor of this embodiment, such as Figure 11 , the photoelectric conversion element is replaced by the photoelectric IC2 instead of the phototransistor PTr, and the limiting resistor R3 is inserted between the photoelectric IC2 and the positive electrode of the DC power supply, which is different from the second embodiment. That is, the photo IC2, the Zener diode ZD1, and the limiting resistor R3 constitute a series circuit.

[0074] The structure of the photoelectric IC2 has a photoelectromotive force mechanism photodiode 20 that generates photoelectromotive force with illuminance, an amplifier 21 that amplifies the photoelectromotive force generated by the photodiode 20, and a transistor 22 whose output terminal of the amplifier 21 is connected to its base. Instead of the collector and emitter of the phototransistor PTr in Embodiment 2, the collector and emitter of the transistor 22 are respectively connected to the limiting resistor R3 and the cathode...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a brightness sensor having the higher resolution in illuminance detection at the case of the lower illuminance even if using a photoelectric conversion element instead of CdS. The brightness sensor comprises a serial circuit in which a phototransistor PTr for varying passing-by current magnitude according to scale of illuminance and a diode Dl are connected in series. When a direct current voltage is applied to the two ends of the serial circuit, the two-end voltage of the diode Dl is outputted as a detected voltage V0. Because the diode Dl has the nonlinear characteristic of the smaller changing ratio of the two-end voltage to the passing-by current as the larger passing-by current in the low current regime before reaching the lowering voltage of the forward direction, in order to operate the diode Dl at the low current regime, the lower passing-by current with respect to illuminance is selected at the phototransistor PTr and the changing ratio of the detected voltage V0 with respect to illuminance is larger as the illuminance is lower.

Description

technical field [0001] The present invention relates to a luminance sensor using a photoelectromotive force mechanism that generates photoelectromotive force according to illuminance, and a photoelectric conversion element whose magnitude of current passing between both ends is determined one-to-one with respect to the photoelectromotive force. Background technique [0002] Known as Figure 18 , using a CdS3 brightness sensor that varies with the illuminance resistance value. This type of brightness sensor has a structure in which a detection resistor R5 is connected in series with CdS3, and the illuminance is detected by outputting the voltage across the detection resistor R5 as a detection voltage V0 in the state where a DC voltage is applied to the series circuit of CdS3 and the detection resistor R5. . [0003] For example, a general brightness sensor with a detectable illuminance range of about 5-10000Lx (lux), such as Figure 19 , the greater the illuminance, the sma...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01J1/42G01J1/00G01J1/44H01L31/08H01L31/10
CPCE04B2/02E04G21/1841
Inventor 森龙一阿部达也
Owner MATSUSHITA ELECTRIC WORKS LTD