EP0762374A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Active driven led matrices
Assignee: Motorola Solutions Inc
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Filing: 1996-07-25
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Granted: —
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Expires: 2016-07-25
Abstract
Abstract A matrix of light emitting devices including a voltage source (60) constructed to repetitiously supply a multi-step voltage waveform (V r , V g , V b ) and a matrix of rows and columns of pixels (40), each pixel (40) being connected to the voltage source (60). A method of driving the matrix including addressing each of the pixels (40) of the matrix by supplying scan and image data activating signals (57, 55) to each of the pixels (40), the image data activating signal (55) being used to activate a pixel (40) by completing a current path from the pixel (40, 44) to a return for the voltage source (48), and activating the voltage source (60) to repetitiously supply multi-step waveforms (V r , V g , V b ) of voltage and sequentially supply each step of each of the multi-step voltage waveforms (V r , V g , V b ) to the pixels (40), and addressing each of the pixels (40) in the matrix for each step supplied.
Inventors
- 👤 Chan-Long Shieh
- 👤 Hsing-Chung Lee
- 👤 Franky So
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 19:21
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; G; G09; G09G; G09G3/00; G09G3/20; G09G3/2007; G09G3/2011; G09G3/22; G09G3/30; G09G3/32; G09G3/3208; G09G3/3225; G09G3/3258; G09G3/3275; G09G3/3291; G09G2300/00; G09G2300/04; G09G2300/0439; G09G2300/0465; G09G2300/08; G09G2300/0804; G09G2300/0809; G09G2300/0842; G09G2310/00; G09G2310/02; G09G2310/0235; G09G2310/0243; G09G2310/0254; G09G2310/0256; G09G2310/0264; G09G2310/027; G09G2320/00; G09G2320/04; G09G2320/043; G09G2330/00; G09G2330/02; G09G3/2018; G09G3/2022; G09G3/2025; G09G3/2077; G09G3/2081
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
180 words
Active drive apparatus for a matrix of light emitting devices characterized by: a voltage source (30) constructed to repetitiously supply a multi-step voltage waveform (V r , V g , V b ) when activated; a matrix including a plurality of rows of light emitting devices (10) and a plurality of columns of light emitting devices (10), each light emitting device (10) having a first contact connected to the voltage source (30) and a second contact; and a plurality of semiconductor switches (12), one each associated with each light emitting device (10), each semiconductor switch (12) having a first current carrying terminal (14) connected to the second contact of the associated light emitting device (10) and a second current carrying terminal (15) connected to a common terminal, each semiconductor switch (12) further having first and second activating input terminals (21, 22), and each semiconductor switch (12) being constructed to complete a circuit between the first and second current carrying terminals (13, 15) only when activating signals are supplied to both of the first and second activating input terminals (21, 22).
Claim 2
Dependent Claim
60 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 1 further characterized in that the multi-step voltage waveform (V r , V g , V b ) which the voltage source (30, 60) is constructed to repetitiously supply includes a plurality of ascending steps of voltage, each representing a level of a multi-bit gray scale.
Claim 3
Dependent Claim
32 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 1 further characterized in that the light emitting devices (10, 45, 46, 47) are organic light emitting diodes.
Claim 4
Dependent Claim
58 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 1 further characterized in that each of the plurality of semiconductor switches (12) includes a first transistor (13) with current carrying electrodes (14, 15) forming the first and second current carrying terminals (14, 15) of the semiconductor switch (12), and a control electrode (20).
Claim 5
Dependent Claim
86 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 4 further characterized in that each of the plurality of semiconductor switches (12) further includes a second transistor (18) with a first current carrying electrode (19) connected to the control electrode (20) of the first transistor (13), a second current carrying electrode (21) forming the first activating input terminal (21) of the semiconductor switch (12), and a control terminal (22) forming the second activating input terminal (22) of the semiconductor switch (12).
Claim 6
Dependent Claim
57 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 1 further characterized in that all of the first activating terminals (21) of each semiconductor switch (12) associated with the light emitting devices (10) in each specific column of light emitting devices (10) are connected together and to a column driver circuit (25).
Claim 7
Dependent Claim
30 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 6 further characterized in that each of the column driver circuits (25) is a digital driver.
Claim 8
Dependent Claim
59 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 6 further characterized in that all of the second activating terminals (22) of each semiconductor switch (12) associated with the light emitting devices (10) in each specific row of light emitting devices (10) are connected together and to an output of a shift register (27).
Claim 9
Dependent Claim
157 words
Active drive apparatus for a matrix of light emitting devices as claimed in claim 8 further characterized by timing circuitry (35) connected to the voltage source (30), the column driver circuits (25) and the shift register (27), the timing circuit (35) being constructed to control the shift register (27) to provide an activating signal to each row in sequence and to control each column driver circuit (25) to provide an activating signal to each column in sequence for each activating signal applied to a row, each activation or addressing of all of the light emitting devices (10) in the matrix being a sub-frame and the timing circuit (35) further constructed to control the voltage source (30) to supply a next sequential step of the multi-step voltage waveform (V r , V g , V b ) each time a sub-frame is completed, a frame being completed when all of the multistep voltages of the waveform are supplied.
Claim 10
Independent Claim
203 words
A method of driving a matrix of light emitting devices characterized by the steps of: providing a voltage source (60) constructed to repetitiously supply a multi-step voltage waveform (V r , V g , V b ) when activated; providing a matrix including a plurality of rows of pixels (40) and a plurality of columns of pixels (40), each pixel (40) having a first contact connected to the voltage source (60) and a second contact; addressing each of the pixels (40) of the matrix by supplying scan and image data (57, 55) activating signals to each of the pixels (40) of the matrix, the image data (55) activating signal being used to determine when a pixel (40) is activated by completing a current path from the second contact (44) of each pixel (40) to a return (48) for the voltage source (60); and activating the voltage source (60) to repetitiously supply multi-step waveforms (V r , V g , V b ) of voltage and sequentially supply each step of each of the multi-step voltage waveforms (V r , V g , V b ) to the pixels (40), and addressing each of the pixels (40) in the matrix for each step supplied.
References Cited (Backward Citations)
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