Passive matrix addressing
Encyclopedia
Passive matrix addressing is an addressing scheme
used in earlier LCD displays, and may be used in future LCD displays. This is a matrix addressing scheme meaning that only m + n control signals are required to address a m × n display. A pixel
in a passive matrix must maintain its state without active driving circuitry until it can be refreshed again.
A new display technology uses a bi-stable pixel, which maintains its state indefinitely without the need for individual transistor elements at each pixel.
The signal is divided into a row or select signal and a column or video signal. The select voltage
determines the row that is being addressed and all m pixels on a row are addressed simultaneously. When pixels on a row are being addressed, a Vsel potential is applied, and all other rows are unselected with a Vunsel potential. The video signal or column potential is then applied with a potential for each m columns individually. An on-lighted pixel
corresponds to a Von, an off-switched corresponds to a Voff potential.
The potential across pixel
at selected row i and column j is
and
for the unselected rows.
Passive matrix addressed displays such as ferroelectric Liquid crystal display
do not need the switch-component of an active matrix display because it has a built-in bistability. Technology for electronic paper
s also have a form of bistability. Displays with bistable pixel elements are addressed with passive matrix addressing scheme, whereas TFT-LCD-displays are addressed using active addressing.
Addressing scheme
There are three different addressing schemes for display devices: direct, matrix, and raster. The purpose of each scheme is to set the state of a pixel to either black/white or, more commonly, a gray-scale level.-Direct addressing:...
used in earlier LCD displays, and may be used in future LCD displays. This is a matrix addressing scheme meaning that only m + n control signals are required to address a m × n display. A pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
in a passive matrix must maintain its state without active driving circuitry until it can be refreshed again.
A new display technology uses a bi-stable pixel, which maintains its state indefinitely without the need for individual transistor elements at each pixel.
The signal is divided into a row or select signal and a column or video signal. The select voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
determines the row that is being addressed and all m pixels on a row are addressed simultaneously. When pixels on a row are being addressed, a Vsel potential is applied, and all other rows are unselected with a Vunsel potential. The video signal or column potential is then applied with a potential for each m columns individually. An on-lighted pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
corresponds to a Von, an off-switched corresponds to a Voff potential.
The potential across pixel
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
at selected row i and column j is
and
for the unselected rows.
Passive matrix addressed displays such as ferroelectric Liquid crystal display
Liquid crystal display
A liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....
do not need the switch-component of an active matrix display because it has a built-in bistability. Technology for electronic paper
Electronic paper
Electronic paper, e-paper and electronic ink are a range of display technology which are designed to mimic the appearance of ordinary ink on paper. Unlike conventional backlit flat panel displays, electronic paper displays reflect light like ordinary paper...
s also have a form of bistability. Displays with bistable pixel elements are addressed with passive matrix addressing scheme, whereas TFT-LCD-displays are addressed using active addressing.
See also
- Active matrix addressing
- Pixel geometryPixel geometryThe components of the pixels in an image sensor or display can be ordered in different patterns, called pixel geometry....
- Liquid crystal displayLiquid crystal displayA liquid crystal display is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals . LCs do not emit light directly....