US6664744B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic backlight for handheld devices
Assignee: Mitsubishi Electric Research Laboratories Inc
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Filing: 2002-04-03
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Granted: 2003-12-16
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Expires: 2022-04-03
Abstract
Abstract An automatic backlight turns on before a user hits a key, but only in dark lighting conditions. A capacitive proximity sensor detects active handling of the device and the backlight itself is used as a light sensor. The circuit requires only a single additional capacitor and three free I/O pins to implement on typical microprocessor-based systems (such as remote controls). Because the system uses the current backlight LED as a sensor, devices can often be upgraded to include this feature without changing the existing packaging.
Inventors
- 👤 Paul H. Dietz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:38
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/02; H04M1/22; G; G09; G09G; G09G3/00; G09G3/20; G09G3/34; G09G3/3406; G09G2320/00; G09G2320/06; G09G2320/0626; G09G2360/00; G09G2360/14; G09G2360/144; G09G3/04; G09G3/06; G09G3/12; G09G3/14; G09G3/22; G09G3/30; G09G3/32; H01; H01H; H01H2219/00; H01H2219/036; H01H2219/038; H04W; H04W52/00; H04W52/02; H04W52/0209; H04W52/0261; H04W52/0267; H04W52/027; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
90 words
An automatic backlight, comprising: an LED coupled in series with a resistor; a micro-processor having a first I/O pin connected to the LED and a second I/O pin coupled to the resistor; means for periodically driving the LED in forward bias to emit light; means for periodically driving the LED in reverse bias; means for discharging the LED after driving the LED in reverse bias to measure a level of ambient light; and means for adjusting a level of the emitted light according to a level of measured ambient light.
Claim 2
Dependent Claim
90 words
An automatic backlight, comprising: an LED coupled in series with a resistor; a micro-processor having a first I/O pin connected to the LED and a second I/O pin coupled to the resistor; means for periodically driving the LED in forward bias to emit light; means for periodically driving the LED in reverse bias; means for discharging the LED after driving the LED in reverse bias to measure a level of ambient light; and means for adjusting a level of the emitted light according to a level of measured ambient light.
Claim 3
Dependent Claim
16 words
The automatic backlight of claim 1 wherein the level of emitted light is on or off.
Claim 4
Dependent Claim
31 words
The automatic backlight of claim 1 further comprising: means for measuring a capacitive coupling with a user, and only driving the LED when there is a capacitive coupling with the user.
Claim 5
Dependent Claim
17 words
The automatic backlight of claim 1 further comprising: means for measuring a capacitive coupling with a user.
Claim 6
Dependent Claim
23 words
The automatic backlight of claim 4 wherein the LED is driven only when the capacitive coupling with the user exceeds a predetermined threshold.
Claim 7
Dependent Claim
26 words
The automatic backlight of claim 4 wherein a standby signal is transmitted to a controlled device when the capacitive coupling with the user exceeds a threshold.
Claim 8
Independent Claim
85 words
A method for operating an automatic backlight, comprising: coupling an LED in series with a resistor; connecting a first I/O pin of a microprocessor to the LED and a second I/O pin to the resistor; periodically driving the LED in forward bias to emit light; periodically driving the LED in reverse bias; discharging the LED after driving the LED in reverse bias to measure a level of ambient light; and adjusting a level of the emitted light according to a level of measured ambient light.
Claim 9
Independent Claim
85 words
A method for operating an automatic backlight, comprising: coupling an LED in series with a resistor; connecting a first I/O pin of a microprocessor to the LED and a second I/O pin to the resistor; periodically driving the LED in forward bias to emit light; periodically driving the LED in reverse bias; discharging the LED after driving the LED in reverse bias to measure a level of ambient light; and adjusting a level of the emitted light according to a level of measured ambient light.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2006-12-15 | 2007-06-16 | 2007-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-12-15 | 2011-06-16 | 2011-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-12-15 | 2015-06-16 | 2015-12-16 | $7700.00 | Window Closed / Lapsed |