公开(公告)号：US20220165208A1

公开(公告)日：2022-05-26

申请号：US17521993

申请日：2021-11-09

Applicant: Jasper Display Corp.

Inventor： Kaushik Sheth ,  Bo Li ,  Edwin Lyle Hudson ,  Jeffrey Li ,  Robert Lo ,  David Charles McDonald

IPC: G09G3/32

Abstract: A method for providing gray scale for an array of current emissive devices sensitive to the current level driving them, such as an LEDs, is disclosed. Multiple current sources are operated in parallel for each emissive device with the on/off state of each of the multiple current source controlled by a memory circuit. Means for pulse width modulating the array of current sensitive devices to enable greater control over gray scale is presented.

公开(公告)号：US20220148497A1

公开(公告)日：2022-05-12

申请号：US17584668

申请日：2022-01-26

Applicant: Jasper Display Corp.

Inventor： Bo Li ,  Kaushik Sheth

IPC: G09G3/32

Abstract: A backplane suitable to pulse width modulate an array of emissive pixels with a current that is substantially constant over a wide range of temperatures. A current control circuit provides means to provide a constant current to an array of current mirror pixel drive elements. The current control circuit comprises a thermally stable bias resistor and a thermally stable band-gap voltage source to provide thermally stable controls and a large L p-channel reference current FET with an associated large L n-channel bias FET configured to provide a reference current at a required voltage to the gate of a large L p-channel current source FET. The current control circuit and the current mirror pixel drive elements are similar circuits with one current control circuit able to control a substantial number of pixel drive elements.

公开(公告)号：US20220130344A1

公开(公告)日：2022-04-28

申请号：US17568831

申请日：2022-01-05

Applicant: Jasper Display Corp.

Inventor： Bo Li ,  Kaushik Sheth ,  Edwin Lyle Hudson

IPC: G09G3/36 ,  G11C11/419 ,  G11C11/418 ,  G11C11/412

Abstract: A backplane design for delivering image data in an efficient manner to a memory cell forming a part of a pixel drive circuit comprises a word line design and a column data register release signal delivery design that are speed matched and a complementary bit line delivery design that is speed matched to a row decoder signal circuit operative to pull a word line driver to a state to enable the memory circuits of that row to receive data from the column drivers for each column. The speed matching is effective over a range of operating temperatures because the circuit designs are substantially identical.

公开(公告)号：US20220108651A1

公开(公告)日：2022-04-07

申请号：US17552158

申请日：2021-12-15

Applicant: Jasper Display Corp.

Inventor： Edwin Lyle Hudson ,  Bo Li

IPC: G09G3/32 ,  G11C11/412

Abstract: A plurality of pixel drive circuits form part of an array of emissive elements. The plurality of pixel drive circuits are disposed to form a plurality of rows and a plurality of columns. The plurality of pixel drive circuits are organized into sets of pixel drive circuits, and each set comprises at least one pixel drive circuit. A FET of a set of pixel drive circuits shares a common well with other FETs of similar function in the same set of pixel drive circuits positioned therein, such that the variance of the threshold voltages of those FETs is substantially reduced. Each of the pixel drive circuits comprises a circuit operative to deliver a current at a predetermined voltage to an emissive device and a memory circuit operative to receive modulation data and to use same to modulate the current output of the pixel drive circuit.

公开(公告)号：US20210201771A1

公开(公告)日：2021-07-01

申请号：US17158493

申请日：2021-01-26

Applicant: Jasper Display Corp.

Inventor： Bo Li ,  Kaushik Sheth

IPC: G09G3/32

Abstract: A backplane suitable to pulse width modulate an array of emissive pixels with a current that is substantially constant over a wide range of temperatures. A current control circuit provides means to provide a constant current to an array of current mirror pixel drive elements. The current control circuit comprises a thermally stable bias resistor and a thermally stable band-gap voltage source to provide thermally stable controls and a large L p-channel reference current FET with an associated large L n-channel bias FET configured to provide a reference current at a required voltage to the gate of a large L p-channel current source FET. The current control circuit and the current mirror pixel drive elements are similar circuits with one current control circuit able to control a substantial number of pixel drive elements.

公开(公告)号：US20210090493A1

公开(公告)日：2021-03-25

申请号：US17115035

申请日：2020-12-08

Applicant: Jasper Display Corp.

Inventor： Edwin Lyle Hudson ,  Bo Li

IPC: G09G3/32

Abstract: A backplane operative to drive an array of emissive pixel elements is disclosed. Each pixel element comprises a memory cell operative to modulate a plurality of current mirror drive elements configured to drive one emissive element, wherein a plurality of current mirror pixel drive elements may be individually enabled by external control signals. The width W of the reference current FET of a first selectable current mirror circuit will differ from the width W of the reference current FET of a second selectable current mirror circuit. The ratio of the width W of the current source FET to the width W of the reference current FET in a first selectable current mirror pixel drive element is equal to the ratio of the width W of the current source FET to the width W of the reference current FET in a second selectable current mirror pixel drive element.

公开(公告)号：US11238782B2

公开(公告)日：2022-02-01

申请号：US16914593

申请日：2020-06-29

Applicant: Jasper Display Corp.

Inventor： Edwin Lyle Hudson ,  Bo Li

IPC: G09G3/32 ,  G11C11/412

Abstract: A backplane operative to drive an array of emissive pixel elements is disclosed. Each pixel element comprises a memory cell operative to modulate a plurality of current mirror drive elements configured to drive one emissive element, wherein one current mirror pixel drive element is always operative to provide current if the memory cell is on and all other current mirror pixel drive elements may enabled subject to external control signals and the memory cell data state. The W/L ratio of each reference current FET is equal to the W/L ratio of all other reference current FETs. The W/L ratio of the current source FETs in each of the current mirror pixel drive elements is equal to the others. The present invention allows adjustment of the current density within the current source FET as well as the sensitivity of the current source FET to threshold voltage variation.

公开(公告)号：US11030942B2

公开(公告)日：2021-06-08

申请号：US16679861

申请日：2019-11-11

Applicant: Jasper Display Corp.

Inventor： Bo Li ,  Kaushik Sheth

IPC: G09G3/32

Abstract: A backplane operative to drive an array of emissive elements forming a part of a display or display like manufacturing device is disclosed. Each emissive element is mounted to a common pad supplied with current from a plurality of pixel drive elements, wherein each pixel drive element is controlled by a resident memory cell. The plurality of pixel drive elements is organized into a block similar to other blocks of pixel drive elements across the array. The common pad may be driven by a larger or lesser number of pixel drive elements than are present in a single block of pixel drive elements. If not needed, specific pixel drive elements present in a single block may be disabled through a mask change.

公开(公告)号：US20200020275A1

公开(公告)日：2020-01-16

申请号：US16459934

申请日：2019-07-02

Applicant: Jasper Display Corp.

Inventor： Bo Li

IPC: G09G3/3241

Abstract: The present invention is to improve on an emissive display by providing a backplane and modulation system that enables fabrication of multi-color or monochrome LED display systems that operate efficiently and without objectionable image artifacts. One aspect of the present invention is to implement the backplane of an emissive display that offers high precision across an array of pixels and extremely low variation. The present invention uses a large L FET to generate a reference current and then uses the same large L FET to act as a current source mirroring the reference current, thereby ensuring a substantially perfect match between reference current FET and current source FET.

公开(公告)号：US11270634B2

公开(公告)日：2022-03-08

申请号：US17158493

申请日：2021-01-26

Applicant: Jasper Display Corp.

Inventor： Bo Li ,  Kaushik Sheth

IPC: G09G3/32

Abstract: A backplane suitable to pulse width modulate an array of emissive pixels with a current that is substantially constant over a wide range of temperatures. A current control circuit provides means to provide a constant current to an array of current mirror pixel drive elements. The current control circuit comprises a thermally stable bias resistor and a thermally stable band-gap voltage source to provide thermally stable controls and a large L p-channel reference current FET with an associated large L n-channel bias FET configured to provide a reference current at a required voltage to the gate of a large L p-channel current source FET. The current control circuit and the current mirror pixel drive elements are similar circuits with one current control circuit able to control a substantial number of pixel drive elements.