CN1333326C - Illuminant brightness control device for optical mouse - Google Patents

Abstract

The present invention relates to a control device for the brightness of a light source of an optical mouse, which comprises a light source, a current switch device and a control device. The light source is used for lightening a sampling plane of a mouse; the current switch device is provided with a plurality of switch devices, each switch device is coupled with the light source, and the current which flows the light source is changed when one switch device is switched on; the magnitude of the current which flows the light source on the light source is controlled through whether the switch devices of the current control device are switched on to control the brightness of the light source.

Description

Optical mouse light-source brightness control device

Technical field

The invention relates to the technical field of optical mouse, refer to a kind of optical mouse light-source brightness control device especially.

Background technology

In general existing optical mouse, be mouse pad or other objects to be carried out rayed with a light emitting diode (LED), again by the image framework (Frame) on the image sensor retrieval mouse pad, image relatively and obtain the motion-vector of this optical mouse is by direction and the distance to judge that optical mouse moves.Fig. 1 is the circuit block diagram of existing optical mouse, its comprise a light source 210,

One resistance 220 and an optical processor 230.This light source 210 is a light emitting diode (LED), and it utilizes the value of this resistance 220, with the adjustment magnitude of current of light source 210 of flowing through, and determines the brightness of this light source 210.Existing optical mouse mainly contains dual mode to the control of light-emitting diode lighting, is illustrated in figure 2 as the control timing figure to light-emitting diode lighting, and wherein, the framework signal is to be the start signal of each image framework or synchronizing signal.First kind of mode is usual pattern (Normal mode), whether lighting of this light emitting diode 210, be whether to use decision by optical mouse, during using (Active), all light, and all do not light during (Idle) during in non-moving detection in optical mouse, therefore, light a lamp/time of turning off the light can cross over whole framework.And the second way is shutter mode (Shutter mode), whether lighting of light emitting diode 210, be that and then shutter opening decides (see figure 2) during active, only when shutter starts, just light light emitting diode, and adjust the exposure that this optical processor 230 is received according to the switching time of shutter.

With aforesaid optical mouse, when this resistance 220 was soldered to circuit board, the magnitude of current of this light source 210 of flowing through was promptly fixing, that is the brightness of this light source 210 can't remake the elasticity adjustment.When the induction sensitivity of this optical processor 230 very high and to light when very sensitive, since the lighting of light source 210 continue during the shutter opening or even during whole optical mouse uses (Acttve), even and might cause shutter can't dwindle again and image that this optical processor 230 is responded to still has saturated phenomenon, and then cause optical mouse can't carry out coherent detection.

In addition, facing dark drawing with aforementioned mouse, need long aperture time to come imaging, because the brightness of the demand of processing speed so light source 210 must be kept certain high brightness, under the suspend state (USB Suspend current standard is restricted to 500uA), and the unlatching light source 210 of long period and cause to meet correlated current restriction standard, therefore the aforementioned mouse with prior art can't move detection under the Suspend state, can't realize moving and wake (Motion Wakeup) function up.

In addition, because light source 210 is lighted extinguish, it is excessive to cause immediate current to consume, and is easy to generate noise.As shown in Figure 3, the electric current of this light source 210 of flowing through when light source 210 is opened and closed (A, B place), has a too drastic phenomenon (over-shooting and under-shooting), causes the misoperation of optical mouse easily because of the difference of video imaging.

Summary of the invention

A purpose of the present invention is that a kind of optical mouse light-source brightness control device is being provided, so that the too drastic phenomenon that is produced can avoid prior art to open or close because of light source the time.

Another object of the present invention is that a kind of optical mouse light-source brightness control device is being provided, so that can avoid prior art can't dwindle and image that optical processor is responded to still has saturated phenomenon at shutter again.

Another object of the present invention is that a kind of optical mouse light-source brightness control device is being provided, so that can augment the deficiency of prior art on light source control, the present invention can see through the brightness of flexible reduction light source, with the long shutter opening time, obtain required image, and power consumption on average can reach relevant current standard, to realize the mobile arousal function of suspend state.

According to a characteristic of the present invention, be to propose a kind of optical mouse light-source brightness control device, this device comprises: a light source, a contact maker and an optical processor.This light source is in order to illuminate a sample plane that is positioned at optical mouse below; This contact maker has the plurality of transistors switchgear, and each transistor switch device is coupled to this light source, with when the transistor switch device conducting, provides an electric current with this light source of flowing through; And this optical processor is coupled to the plurality of transistors switchgear of this contact maker, and with the conducting of controlling a plurality of switchgears whether, the size of the electric current of this light source so that control is flowed through reaches the purpose of control light-source brightness.

According to another characteristic of the present invention, be to propose a kind of optical mouse light-source brightness control device, this device comprises a light source, a contact maker, a voltage-operated device and an optical processor.This light source is in order to illuminate a sample plane that is positioned at optical mouse below; This contact maker has at least one transistor switch device, and this at least one transistor switch device is coupled to this light source, with when this at least one transistor switch device conducting, provides an electric current this light source of flowing through; Its output of this voltage-operated device is to be connected to this contact maker, by the voltage swing by its output, controls the electric current of this contact maker of flowing through; This optical processor is to be coupled to this voltage-operated device, and with the voltage swing of the output of setting this voltage-operated device, the size of the electric current of this light source so that control is flowed through reaches the purpose of control light-source brightness.

Description of drawings

Fig. 1 is existing optical mouse control timing figure to light-emitting diode lighting when shutter mode is closed;

Fig. 2 is the synoptic diagram of existing optical mouse LED control device;

Fig. 3 is a too drastic phenomenon synoptic diagram when having optical mouse to light-emitting diode lighting now;

Fig. 4 is the circuit diagram of a preferred embodiment of the present invention;

Fig. 5 is the control timing figure of the present invention to light-emitting diode lighting;

Fig. 6 is another control timing figure of the present invention to light-emitting diode lighting;

Fig. 7 is the circuit diagram of another preferred embodiment of the present invention;

Fig. 8 is the circuit diagram of a preferred embodiment more of the present invention;

Fig. 9 is the again control timing figure of the present invention to light-emitting diode lighting.

Embodiment

The preferred embodiment of relevant optical mouse LED control method of the present invention and device, the circuit diagram that please show with reference to Fig. 4 earlier, it comprises a light source 410, a contact maker 420 and an optical processor 430, and wherein, this light source 410 is preferably a light emitting diode (LED).This light emitting diode 410 its in order to illuminate the sample plane of mouse, its positive pole is connected to a noble potential, negative pole is connected to this contact maker 420.It has a plurality of switchgears this contact maker 420, and each switchgear is coupled to this light source 410 individually, with when the switchgear conducting, provides an electric current this light source 410 of flowing through.And this optical processor 430 is to be coupled to this contact maker 420, with the conducting of a plurality of switchgears of controlling this contact maker 420 whether, and the size of the electric current of this light source 410 so that control is flowed through.

As shown in Figure 4, these a plurality of switchgears are made up of nmos pass transistor 421,423,425 and 427, nmos pass transistor 421,423,425 and 427 drain electrode are connected to the negative pole of this light emitting diode 410 respectively, its source electrode is connected to an electronegative potential (GND) respectively, and its grid is connected to control signal A_EN, B_EN, C_EN and D_EN that this optical processor 430 is produced respectively.With when this control signal A_EN, B_EN, C_EN and D_EN are noble potential, respectively with corresponding nmos pass transistor conducting, so that the electric current of this light emitting diode 410 can be flowed through on it, to form an electric current loop, so that light light emitting diode.

Use technology of the present invention, this optical processor 430 produces control signal A_EN, B_EN, C_EN and the D_EN of noble potential as shown in Figure 5 in regular turn, so can be with this nmos pass transistor 421,423,425 and 427 conductings, the electric current of this light emitting diode 410 increases gradually so that flow through, the too drastic phenomenon that is produced when avoiding prior art to open or close because of this light emitting diode 410 is to reduce the misoperation of optical mouse.

Fig. 6 is the Another Application example of technology of the present invention, when the induction sensitivity of this optical processor 430 very high and to light when very sensitive, since the lighting of light emitting diode 410 continue during the shutter opening or even during whole optical mouse uses (Active), even and might cause shutter can't dwindle again and image that this optical processor 430 is responded to still has saturated phenomenon, and then cause optical mouse to operate.At this moment, this optical processor 430 produces corresponding control signal A_EN, B_EN, C_EN and D_EN as shown in Figure 6, so can be and this nmos pass transistor 423 and 427 is closed with this nmos pass transistor 421 and 425 conductings, the electric current of this light emitting diode 410 is at ordinary times half so that flow through, to keep away the image that this optical processor 430 responded to saturated phenomenon is arranged still, to reduce the misoperation of optical mouse.

Fig. 7 is an another embodiment of the present invention, these a plurality of switchgears are made up of PMOS transistor 721,723,725 and 727, PMOS transistor 721,723,725 and 727 drain electrode are connected to the positive pole of this light emitting diode 410 respectively, its source electrode is connected to a noble potential (VDD) respectively, and its grid is connected to control signal A_EN*, B_EN*, C_EN* and D_EN* that this optical processor 430 is produced respectively.With when this control speech which A_EN*, B_EN*, C_EN* and D_EN* are electronegative potential, respectively with corresponding PMOS transistor turns, so that the electric current of this light emitting diode 410 can be flowed through on it, to form an electric current loop, so that light light emitting diode.

Fig. 8 is an another embodiment of the present invention, and it comprises a light source 410, a contact maker 420, an optical processor 430 and a voltage-operated device 810, and wherein these voltage-operated device 810 output terminals are to be connected to this contact maker 420.This voltage-operated device 810 can be a digital to analog converter (Digital to Analogue converter, DAC), this contact maker 420 can be a nmos pass transistor, and the exit point H of this digital to analog converter 810 then is connected to the grid of this nmos pass transistor 420.The electric current of this nmos pass transistor 420 of then flowing through is

$i_D=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}{(v_{\mathrm{GS}}-V_T)}^2=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}{(V_H-V_T)}^2,$

Wherein, V _HVoltage for end points H.That is this optical processor 430 can see through a bus 820 so that this voltage-operated device 810 is carried out the setting of exit point H voltage, by this control electric current of this nmos pass transistor 420 of flowing through, so that control the brightness of this led light source 410.

Fig. 9 is the control timing figure of the light-emitting diode lighting of Fig. 8 embodiment, wherein V _TBe 0.5V.When T1, this optical processor 430 via bus 820 with a 4C _HValue be written to this digital to analog converter 810, be VH=(76/256) * 5=1.5V and make the voltage of the exit point H of this digital to analog converter 810, this moment this nmos pass transistor 420 be to be in the saturation region, so the electric current of this nmos pass transistor 420 of flowing through is

$i_D=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}{(1.5-0.5)}^2=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}=I_0,$

This moment, this nmos pass transistor that works in the saturation region was to be equivalent to a variable resistor.When T2, this optical processor 430 via bus 820 with 1 _HValue be written to this digital to analog converter 810, be VH=(98/256) * 5=1.914V and make the voltage of the exit point H of this digital to analog converter 810, the electric current of this nmos pass transistor 420 of flowing through this moment is

$i_D=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}{(1.914-0.5)}^2=\frac{{\mathrm{\μ}}_n{C}_{\mathrm{ox}}}{2}\frac{W}{L}{\left(1.414\right)}^2\≈{2I}_0,$

That is, this digital to analog converter 810 can produce different output voltages as shown in Figure 9 in regular turn, so controllable flow is through the electric current of this nmos pass transistor 420, the electric current of this light emitting diode 410 increases gradually so that flow through, and the too drastic phenomenon that is produced when avoiding prior art to open or close because of this light emitting diode 410, to reduce the misoperation of optical mouse.

By above explanation as can be known, the present invention mainly utilizes a plurality of MOS to form this contact maker 420, and control the MOS switch conduction or close according to the control signal that this optical processor 430 is produced, with so the flow through electric current of this light emitting diode 410 of control, or utilize voltage that this voltage-operated device 810 produced to control this contact maker 420, the electric current of this light emitting diode 410 so that control is flowed through, the too drastic phenomenon that is produced when avoiding prior art to open or close because of this light emitting diode 410, or shutter can't dwindle and image that this optical processor 430 is responded to still has saturated phenomenon again.

The foregoing description only is to give an example for convenience of description, and the interest field that the present invention advocated should be as the criterion so that claim is described certainly, but not only limits to the foregoing description.

Claims (12)

1, a kind of optical mouse light-source brightness control device is characterized in that, comprises:

One light source, it is in order to illuminate a sample plane that is positioned at optical mouse below;

One contact maker, it has the plurality of transistors switchgear, and each transistor switch device is coupled to this light source, with when the transistor switch device conducting, provides an electric current this light source of flowing through; And

One optical processor is coupled to the plurality of transistors switchgear of this contact maker, with the conducting of controlling this plurality of transistors switchgear whether, and the size of the electric current of this light source so that control is flowed through.

2. device as claimed in claim 1 is characterized in that, described this plurality of transistors switchgear is to be nmos pass transistor.

3. device as claimed in claim 1 is characterized in that, described this plurality of transistors switchgear is to be the PMOS transistor.

4. device as claimed in claim 1 is characterized in that, described this optical processor is in regular turn with this plurality of transistors switchgear conducting, so that the electric current of this light source of flowing through increases gradually.

5. device as claimed in claim 1 is characterized in that, described this optical processor is that part plurality of transistors switchgear is opened, with the flow through size of electric current of this light source of adjustment.

6. device as claimed in claim 1 is characterized in that, described this light source is a light emitting diode.

7. an optical mouse light-source brightness control device is characterized in that, comprises:

One light source, it is in order to illuminate a sample plane that is positioned at optical mouse below;

One contact maker, it has at least one transistor switch device, and this at least one transistor switch device is coupled to this light source, with when this at least one transistor switch device conducting, provides an electric current this light source of flowing through;

One voltage-operated device, its output are to be connected to this contact maker, by the voltage swing of its output, control the electric current of this contact maker of flowing through; And

One optical processor is to be coupled to this voltage-operated device, with the voltage swing of the output of setting this voltage-operated device, the size of the electric current of this light source so that control is flowed through.

8. device as claimed in claim 7 is characterized in that, described this at least one transistor switch device is to be nmos pass transistor.

9. device as claimed in claim 7 is characterized in that, described this light source is to be a light emitting diode.

10. device as claimed in claim 7 is characterized in that, described this voltage-operated device is to be a digital to analog converter.

11. device as claimed in claim 8 is characterized in that, described this nmos pass transistor is to work in the saturation region.

12. device as claimed in claim 11 is characterized in that, the described nmos pass transistor that this works in the saturation region is to be equivalent to a variable resistor.

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