# US 11,114,025 B2 · Method for sensing light

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,114,025 B2
- Document ID: US11114025B2
- Status: Granted
- Kind: B2
- Application number: 16/964,792
- Filed: 2019-01-31
- Published: 2021-02-25
- Granted: 2021-09-07
- Earliest claimed: 2018-01-31
- Assignees: Ams AG
- Applicants: ams AG
- Inventors: Bernhard Greimel-Längauer; Joachim Lechner; Josef Kriebernegg
- Web page: https://patentgrep.com/patent/US11114025B2

## CPC

- G09G 3/3208: organic, e.g. using organic light-emitting diodes [OLED]
- G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)}
- G01J 1/4204: {with determination of ambient light (solar light G01J2001/4266)}
- G09G 5/10: Intensity circuits
- H04M 1/0266: {for a display module assembly}
- G09G 2310/0237: Switching ON and OFF the backlight within one frame
- G09G 2310/06: Details of flat display driving waveforms
- G09G 2310/08: Details of timing specific for flat panels, other than clock recovery
- G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
- G09G 2320/0633: by amplitude modulation of the brightness of the illumination source
- G09G 2320/064: by time modulation of the brightness of the illumination source
- G09G 2320/0666: for control of colour parameters, e.g. colour temperature
- G09G 2360/144: the light being ambient light
- G09G 2360/145: the light originating from the display screen
- H04M 2250/12: including a sensor for measuring a physical value, e.g. temperature or motion
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)

## Abstract

A method is proposed for sensing light being incident on an electronic device. The electronic device comprises a display and a light sensor arrangement which is mounted behind the display such as to receive incident light through the display. The method comprises the step of repeatedly switching the display on and off depending on a modulation signal, wherein a sub-frame is defined by an on-state and a consecutive off-state of the display. The modulation signal depends on at least one modulation parameter. In a first sub-frame a display brightness is set to a first level depending on a first value of the at least one modulation parameter. Then a first frame count is determined by integrating the incident light by means of the light sensor arrangement during the first sub-frame. In a second sub-frame the display brightness is set to a second level depending on a second value of the at least one modulation parameter. Then a second frame count is generated by integrating the incident light by means of the light sensor arrangement during the second frame. Finally, an ambient light level is determined depending on the first frame count and the second frame count.

## Claims

### Claim 1

A method for sensing light being incident on an electronic device, the electronic device comprising a display and a light sensor arrangement mounted behind the display such as to receive incident light through the display, the method comprising the steps of:
repeatedly switching the display on and off depending on a modulation signal, wherein a sub-frame is defined by an on-state and a consecutive off-state of the display, and the modulation signal depends on at least one modulation parameter, in a first sub-frame, setting a display brightness to a first level depending on a first value of the at least one modulation parameter, determining a first frame count by integrating the incident light by means of the light sensor arrangement during the first sub-frame, in a second sub-frame, setting the display brightness to a second level depending on a second value of the at least one modulation parameter, generating a second frame count by integrating the incident light by means of the light sensor arrangement during the second sub-frame, and determining an ambient light level depending on the first frame count and the second frame count, wherein for at least two sub-frames the first frame count, denoted FC1, and the second frame count denoted FC2, are expressed as follows:
FC1=AL+DL1=AL+DL(1.±.MI1/2)B
FC2=AL+DL2=AL+DL(1.∓.MI2/2)B,
wherein DL denotes a maximum brightness or defined brightness, DL1 and DL2 the first and second display level, MI1 and MI2 denote first and second modulation indices, and B denotes a mean display brightness.

### Claim 2 (depends on 1)

The method according to claim 1, wherein a first integration time corresponds to a duration of the first sub-frame such that the first frame count is indicative of the incident light integrated during the first integration time, and a second integration time corresponds to a duration of the second sub-frame such that the second frame count is indicative of the incident light integrated during the second integration time.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the first integration time corresponds to a fraction of the duration of the first sub-frame, and/or the second integration time corresponds to a fraction of the duration of the second sub-frame.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the first and the second integration times are the same in value.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the modulation signal comprises a succession of pulses with consecutive high and low levels, and the sub-frames are synchronized to the pulses of the modulation signal and/or the synchronization signal.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the modulation signal is a pulse width modulation signal.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the pulses of the modulation signal are modulated each have a duty cycle and each duty cycle is set by means of a duty cycle parameter as modulation parameter.

### Claim 8 (depends on 5)

The method according to claim 5, wherein the pulses of the modulation signal each have an amplitude, and the amplitudes are set by means of an amplitude parameter as modulation parameter.

### Claim 9 (depends on 8)

The method according to claim 8, wherein a supply current of the display and/or pixels of the display is set by means of the amplitude parameter.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the pulses of the modulation signal are modulated by means of a timing parameter as modulation parameter, wherein a duration of sub-frames are altered as a function of the modulation parameter, or wherein the light sensor arrangement comprises a light sensor and the ambient light level is used to adjust the display brightness.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the light sensor arrangement comprises a color light sensor and the ambient light level is used to adjust a display color, such as, a color temperature value of the display.

### Claim 12 (depends on 1)

The method according to claim 1, wherein two consecutive sub-frames are used as first and second sub-frames to determine the ambient light level, or a number of first sub-frames and a number of second sub-frames are used to determine the ambient light level, wherein the sub-frames are from the same frame or from different frames.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the display brightness at the first and/or second level is set for a region of interest and the light sensor arrangement integrates incident light locally from the region of interest, or the display brightness at the first and/or second level is set for the whole display and the light sensor arrangement integrates incident light globally for the whole display.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the display brightness BR over one frame rate has a same level, wherein Ton represents a mean active pulse time of the sub-frames during a frame with frame rate FR such that BR=Ton/FR.

### Claim 15 (depends on 14)

The method according to claim 14, wherein over one frame rate FR the display brightness BR has the same level, wherein the modulation signal is modulated such that off times for said frame cancel out.

### Claim 16 (depends on 14)

The method according to claim 14, wherein over one frame rate FR the display brightness BR has the same level, wherein the modulation signal is modulated such that the amplitudes are set around a mean amplitude.

### Claim 17 (depends on 1)

The method according to claim 1, wherein the at least two sub-frames have same modulation indexes such that MI1=MI2, such that the display level is determined as:
DL
=
FC
⁢
⁢
2
-
FC
⁢
⁢
1
MI
⁢
⁢
1
·
B
and the ambient light level AL is determined as: AL=FC2−DLB.

### Claim 18

A method for sensing light being incident on an electronic device, the electronic device comprising a display and a light sensor arrangement mounted behind the display such as to receive incident light through the display, the method comprising the steps of: repeatedly switching the display on and off depending on a modulation signal, wherein a sub-frame is defined by an on-state and a consecutive off-state of the display, and the modulation signal depends on at least one modulation parameter, in a first sub-frame, setting a display brightness to a first level depending on a first value of the at least one modulation parameter, determining a first frame count by integrating the incident light by means of the light sensor arrangement during the first sub-frame, in a second sub-frame, setting the display brightness to a second level depending on a second value of the at least one modulation parameter, generating a second frame count by integrating the incident light by means of the light sensor arrangement during the second sub-frame, and determining an ambient light level depending on the first frame count and the second frame count, wherein a synchronization signal is provided and comprises synchronizing pulses, wherein two consecutive synchronizing pulses define a frame of the display, a frame comprises at least the first sub-frame and the second sub-frame, and a succession of sub-frames is synchronized with the synchronization signal.