Amorphous Optical Sensors - Sanyo EP92H Brochure

Achieving Low Power and Superb Viewability

Amorphous Optical Sensors

Amorphous Silicon Solar Cells
Amorphous Optical Sensors
These devices are a type of photodiode that can detect the presence/absence of ambient light, or the intensity of ambient light.
Amorphous optical sensor spectral sensitivity Illumination-dependent characteristics of ISC
Visible wavelength amorphous optical sensor
Human visual sensitivity
Single-crystal silicon optical sensors
1
0.5
400 500 600 700 800 900 1000
Wavelength [nm]
High sensitivity in the visible region
The output current is proportional
The human eye is sensitive to light with
wavelengths from about 400 nm to about 700 nm.
Since the output current changes proportionally to
Since these amorphous optical sensors have
the light striking the sensor, these devices provide
sensitivity to essentially the same wavelengths,
precise detection.
they provide sensing that is close to that of the
human eye.
Amorphous Optical Sensor Application Examples
Automatic adjustment of LCD backlight and operating panel buttons
These sensors can be used to sense the ambient
illumination level and automatically turn off these lamps in
bright operating environments. This reduces unnecessary
power consumption and creates LCD screen display that is
easy to see whatever the ambient lighting.
Increased operating time for portable electronic
equipment due to reduced power consumption!
LCD backlight level automatically adjusted to just the
right level for viewing according to the ambient
illumination level
Bright environments Dark environments
LCD backlight
OFF ON
Automatic brightness adjustment
Button lamps
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Amorphous optical sensor pattern examples
Measured at FL (for color illuminator): 1 to 10 kLx
at SS (Solar Simulator) : 10 to 10k Lx
1.E-03
[AM-30-26] 2.1
1.E-04
1.E-05
1.E-06
1.E-07
0.88
1.E-08
0.84
1.E-09
1.E-10
[AM-30-26]
1 10 100 1,000 10,000 100,000
Illumination [Lux]
Flexible pattern geometries and sizes
to the illumination
These devices support designs with sizes and
shapes that correspond to the target application.
Cell phone with built-in optical sensor
Bright environments Dark environments
LCD backlight OFF LCD backlight ON
About 300Lx About 3Lx
Button lamps OFF Button lamps OFF
5 to 20mA 55 to 70mA
Cell phone without built-in optical sensor
Bright environments Dark environments
LCD backlight ON LCD backlight ON
Unnecessary power Unnecessary power
consumption occurs consumption occurs
Button lamps ON Button lamps ON
95 to 110mA 95 to 110mA
These devices are a type of photodiode that can detect light with about the same sensitivity as the human eye. Since these
devices flexibly support a wide range of end product designs and sizes, they can be used to control the LCD backlight and
button lamps in cell phones to implement power saving automatic brightness adjustment
Amorphous Optical Sensor Structure
Like amorphous silicon solar cells, amorphous optical
sensor use the photovoltaic effect in semiconductors.
When light hits a semiconductor, electrons and holes
are created, the electrons diffuse in the n-type
semiconductor, and the holes diffuse in the p-type
semiconductor. As a result, a current will flow when the
two semiconductor types are connected externally.
Amorphous Optical Sensor Circuit Examples
With an operational amplifier
Amorphous
Optical Sensor
LCD backlight ON (AM-30-26)
The current output from the amorphous optical sensor is
converted to a voltage, and signal processing is applied to that
voltage.
Button lamps ON Normally, an operational amplifier is used for linear amplification.
95 to 110mA
Amorphous Optical Sensor Product Lineup
Type No.
LCD backlight ON
AM-30-26
Contact your SANYO sales representative for details on these products
Button lamps ON
95 to 110mA
Transparent electrode
p
i
Metallic electrode
Without an operational amplifier
3V
A Amorphous
Optical Sensor
(AM-30-26)
The amorphous optical sensor is connected to a resistor and the
voltage is input directly to an A/D converter for discrimination.
External dimensions (mm) Short-circuit current (I , typical)
SC
2.1 2.0 mm 2
*1
1.2 A
(glass thickness: 0.4 mm)
Light
(+) Anode
+
+
+
+ +
+
+
+
+
+ +
+
+
+
+
+
+
+
+
+
+
(-) Cathode
n
Electron
+
Electron hole
C R
Dark current (V = 50 mV) MAX.
R
10 pA
*1 : at 1000Lux, Fluorescent Light for color illuminator
33