Patent Description:
A technology of detecting approach of a hand of a user to a display surface of a display by irradiating a front side of the display surface of the display with infrared light from several infrared LEDs arranged along a lower side of the display surface of the display below the lower side and detecting reflection light of the infrared light due to the hand of the user by photodiodes has been known as the technology of detecting the approach of the hand of the user to the display surface of the display (for example, <CIT>).

<CIT> discloses a light sensor system which includes at least one light emitter, a light sensor unit and a processing unit. The light sensor unit is arranged to receive reflected light from an object in accordance with a time sequence in which the at least one light emitter is activated, and accordingly output a plurality of reflected signals. The processing unit is arranged to receive the reflected signals, identify a signal function of time by referring to occurrence sequence of local peak levels of the reflected signals, and determine motion of the object according to the signal function of time.

<CIT> discloses a vehicle display device comprising a display; a gesture sensing unit disposed in the vicinity of the display so as to generate a first sheet beam to be emitted in a first direction and a second sheet beam to be emitted in a second direction different from the first direction, and sensing a three-dimensional gesture of an object through the first and second sheet beams; and a processor for providing a control signal according to the three-dimensional gesture.

In general, since the infrared LED has directivity, since a direction viewed from the infrared LED is a direction in which an angle with respect to a central axis of a directional angle becomes large, an intensity of infrared light becomes weak.

Accordingly, in the above-mentioned technology of detecting the approach of the hand of the user to the display surface of the display by providing several infrared LEDs below the lower side of the display, a region in which the irradiation intensity of the infrared light is weaker than in another region is formed below the display positioned close to the infrared LED in the direction of the central axis of the directional angle of the infrared LED, and thus, the detection of the approach of the hand of the user to this region may not be satisfactorily performed.

Such a problem can be solved when a plurality of infrared LEDs is arranged at narrow intervals such that a region in which the irradiation intensity of the infrared light is weak is not formed. However, in this case, cost increases as the required number of infrared LEDs increases.

Therefore, an object of the present invention is to satisfactorily detect the approach of the hand of the user in approximately the entire region of the display surface of the display while using a relatively small number of infrared LEDs.

The invention relates to a proximity detection device according to the appended claims. Embodiments are disclosed in the dependent claims.

According to an embodiment, there is disclosed a proximity detection device that detects approach of a user to a display surface of a display. The proximity detection device includes a plurality of infrared light sources that is arranged outside and along a first side which is one side of the display surface of the display, and configured to emit infrared light passing through an area in front of the display surface diagonally, a plurality of photodetectors each arranged between two infrared light sources along the first side of the display surface, a proximity detection unit configured to detect the approach of the user to the display surface when an intensity which is detected by the photodetector corresponding to the infrared light source according to a predetermined positional correspondence and an intensity of reflection light of the infrared light emitted by the infrared light source is used as a first detection reflection intensity of emission light of the infrared light source for each of the plurality of infrared light sources and the intensity of the reflection light of the infrared light indicated by the first detection reflection intensity of the emission light of each infrared light source exceeds a set threshold value, and a threshold value setting unit configured to set a threshold value to the proximity detection unit such that the threshold value changes depending on an evaluation value calculated according to a predetermined evaluation function from each second detection reflection intensity and each first detection reflection intensity by using, as target infrared light sources, one or a plurality of infrared light sources of the plurality of infrared light sources and using, as second detection reflection intensities of emission light of the target infrared light sources, intensities which are intensities of reflection light of infrared light emitted by the target infrared light sources and are detected by the photodetectors further from the target infrared light sources than the photodetectors corresponding to the infrared light sources which are the target infrared light sources according to the correspondence for each target infrared light sources.

In the proximity detection device, the threshold value setting unit may be configured to calculate, as the evaluation value, a ratio of a maximum value of each second detection reflection intensity to a maximum value of each first detection reflection intensity, and set the threshold value to the proximity detection unit such that the threshold value becomes small in a case where the calculated evaluation value is smaller than a predetermined level compared to a case where the evaluation value is not smaller than the predetermined level.

In the proximity detection device, the threshold value setting unit may be configured to calculate, as the evaluation value, a ratio of a maximum value of each second detection reflection intensity to a maximum value of each first detection reflection intensity, and set the threshold value to the proximity detection unit such that the threshold value becomes small as the calculated evaluation value becomes small.

In the proximity detection device, the proximity detection unit may be configured to detect the approach of the user to the display surface when the maximum value of each first detection reflection intensity exceeds the set threshold value.

According to the proximity detection device described above, since it is detected whether or not the reflection occurs in the region close to the side of the display in which the irradiation intensity of the infrared light becomes weak and the infrared light source is arranged and the detection sensitivity of the hand of the user is increased when the reflection occurs in this region, the approach of the hand of the user to the display surface of the display can be detected in a form in which the detection sensitivity of the approach of the user is increased only in this region.

Accordingly, the approach of the hand of the user can be satisfactorily detected in approximately the entire region of the display surface of the display.

The present invention also provides the proximity detection device and a display unit including the display integrated with the proximity detection device.

The present invention also provides an information processing system that includes the proximity detection device, the display, and a data processing device using the display for display output, and notifies the data processing device of the approach of the user to the display surface when the proximity detection device detects the approach.

As described above, according to the present invention, the approach of the hand of the user can be satisfactorily detected in the entire region of the display surface of the display while using a relatively small number of infrared LEDs.

<FIG> illustrates a configuration of an information processing system according to an embodiment.

The information processing system is a system mounted on a vehicle, and includes a data processing device <NUM> that for example executes a car navigation application, a media player application, and the like, a display <NUM> that is used for video display by the data processing device <NUM>, a proximity detection device <NUM>, and other peripheral devices <NUM> used by the data processing device <NUM>.

Here, as illustrated in <FIG>, the display <NUM> and the proximity detection device <NUM> are arranged in the form of an integrated display unit <NUM> such that a display surface is directed rearward at a position between a drive unit's seat and a passenger's seat on a dashboard of the vehicle.

Returning back to <FIG>, the proximity detection device <NUM> includes a proximity detection sensor <NUM> and a proximity detection controller <NUM>.

The proximity detection sensor <NUM> includes four infrared LEDs of an LED <NUM>, an LED <NUM>, an LED <NUM>, and an LED <NUM>, and two photodiodes of a PD <NUM> and a PD <NUM> that detect infrared light.

The proximity detection controller <NUM> includes a drive unit <NUM> that causes the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM> to emit light by driving these LEDs, a detection unit <NUM> that converts current signals output by the PD <NUM> and the PD <NUM> into intensity signals indicating intensities of the infrared light incident on the PD <NUM> and the PD <NUM>, and a detection control unit <NUM> that controls operations of the drive unit <NUM> and the detection unit <NUM>, detects the approach of a hand of a user to the display surface of the display <NUM> by the intensities of the infrared light indicated by the signals converted by the detection unit <NUM>, and notifies the data processing device <NUM> of the detected approach.

Next, assuming that a left-right direction, an up-down direction, and a front-back direction are determined with respect to the display <NUM> as illustrated in <FIG>, the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM> are arranged in this order from left to right at a position slightly below a lower side of the display <NUM> at approximately equal intervals. However, a front direction is a display direction of the display <NUM>.

The PD <NUM> is arranged at an intermediate position between the LED <NUM> and the LED <NUM>, and the PD <NUM> is arranged at an intermediate position between the LED <NUM> and the LED <NUM>. Thus, each PD converts reflection light of the infrared light incident on the LEDs into current signals.

Arrows in <FIG> represent central axes of directional angles of the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM>, and the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM> diagonally irradiates a front upper side of the display <NUM> with the infrared light.

<FIG> illustrates a distribution of the irradiation intensities of the infrared light emitted by the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM> viewed in the front-back direction. Since a direction in which an angle with respect to the central axis becomes large is taken even as viewed from any of the LEDs, a region in which the irradiation intensities become weak is formed at a lower portion of the display <NUM>.

Next, the detection control unit <NUM> of the proximity detection controller <NUM> controls the operations of the drive unit <NUM> and the detection unit <NUM> such that a cycle illustrated in <FIG> is repeatedly performed.

Here, each cycle includes a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A1 indicating the intensity of the infrared light incident on the PD <NUM> and an intensity signal E1 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A2 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A3 indicating the intensity of the infrared light incident on the PD <NUM>, and a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A4 indicating the intensity of the infrared light incident on the PD <NUM> and an intensity signal E2 indicating the intensity of the infrared light incident on the PD <NUM>.

Next, <FIG> illustrates a configuration of the detection unit <NUM>.

As illustrated in this figure, the detection unit <NUM> includes a set of a signal processing unit <NUM> and an analog-to-digital converter <NUM> (A/D <NUM>) provided so as to correspond to each of the two photodiodes of the PD <NUM> and the PD <NUM>.

The signal processing unit <NUM> of each set performs signal processing such as conversion of the current signal output by the corresponding photodiode to a voltage signal, and the analog-to-digital converter <NUM> of each set converts the current signal output by the signal processing unit <NUM> of the same set into a digital signal and outputs the digital signal to the detection control unit <NUM>.

Here, the detection control unit <NUM> of the proximity detection controller <NUM> may control the operations of the drive unit <NUM> and the detection unit <NUM> such that a cycle illustrated in <FIG> is repeatedly performed instead of the cycle illustrated in <FIG>.

The cycle illustrated in <FIG> includes a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A1 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A2 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A3 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal A4 indicating the intensity of the infrared light incident on the PD <NUM>, a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal E1 indicating the intensity of the infrared light incident on the PD <NUM>, and a period in which the drive unit <NUM> causes only the LED <NUM> to emit the light and the detection unit <NUM> outputs an intensity signal E2 indicating the intensity of the infrared light incident on the PD <NUM>.

Here, when the detection control unit <NUM> of the proximity detection controller <NUM> controls the operations of the drive unit <NUM> and the detection unit <NUM> such that the cycle illustrated in <FIG> is repeatedly performed, the detection unit <NUM> has the configuration illustrated in <FIG> instead of the configuration illustrated in <FIG>.

In the configuration illustrated in <FIG>, the detection unit includes a multiplexer <NUM> (MPX <NUM>), one signal processing unit <NUM>, and one analog-to-digital converter <NUM>.

In the cycle illustrated in <FIG>, the multiplexer <NUM> selects the current signal output by the PD <NUM> and outputs the current signal to the signal processing unit <NUM> in the periods in which the detection unit <NUM> outputs the intensity signals A1, A2, and E2 indicating the intensities of the infrared light incident on the PD <NUM>, and selects the current signal output by the PD <NUM> and outputs the current signal to the signal processing unit <NUM> in the periods in which the detection unit <NUM> outputs the intensity signals A3, A4, and E1 indicating the intensities of the infrared light incident on the PD <NUM>. The signal processing unit <NUM> performs signal processing such as conversion of the current signal input from the multiplexer <NUM> into a voltage signal, and the analog-to-digital converter <NUM> converts the voltage signal output by the signal processing unit <NUM> into a digital signal, and outputs the digital signal to the detection control unit <NUM>.

Here, since the cycle illustrated in <FIG> does not include a period in which the intensity signal indicating the intensity of the infrared light incident on the PD <NUM> and the intensity signal indicating the intensity of the infrared light incident on the PD <NUM> are simultaneously acquired, in the cycle illustrated in <FIG> including a period in which the signals are simultaneously acquired, there is an advantage that the number of sets of the signal processing unit <NUM> and the analog-to-digital converter <NUM> which are required as two sets for the detection unit <NUM> as illustrated in <FIG> can be reduced to one set as illustrated in <FIG>.

In the cycles of <FIG> and <FIG>, the intensity signal E1 indicating the intensity of the infrared light incident on the PD <NUM> when only the LED <NUM> emits the light has a large value in a case where the reflection occurs due to the hand of the user in a region A_E1 on an upper left side of the display <NUM> as illustrated in <FIG> compared to a case where the reflection occurs in another region.

This is because the region A_E1 on the upper left side of the display <NUM> is irradiated with the infrared light emitted by the LED <NUM> having a relatively strong intensity and a positional relationship between the LED <NUM>, the PD <NUM>, and the region A_E1 is a positional relationship in which the reflection light of the infrared light emitted by the LED <NUM> due to the reflection occurring in the region A_E1 reaches the PD <NUM> with a relatively strong intensity as illustrated in <FIG>, whereas another region is a region irradiated with the infrared light having a relatively weak intensity emitted by the LED <NUM> or a region in which a positional relationship between the LED <NUM>, the PD <NUM>, and this region is a positional relationship in which the reflection light of the infrared light emitted by the LED <NUM> due to the reflection occurring in this region does not reach the PD <NUM> or reaches the PD <NUM> with a relatively weak intensity as illustrated in <FIG>.

Similarly, in the cycles of <FIG> and <FIG>, the intensity signal E2 indicating the intensity of the infrared light incident on the PD <NUM> when only the LED <NUM> emits the light has a large value in a case where the reflection occurs due to the hand of the user in a region A_E2 on an upper right side of the display <NUM> as illustrated in <FIG> compared to a case where the reflection occurs in another region.

Accordingly, magnitudes of the intensity signals E1 and E2 are indicators of whether or not the hand of the user is positioned in the upper region of the display <NUM> (region A_E1 or region A_E2).

Next, proximity detection processing performed by the detection control unit <NUM> of the proximity detection controller <NUM> will be described.

<FIG> illustrates a procedure of this proximity detection processing.

As illustrated in this figure, when the intensity signals A1, A2, A3, A4, E1, and E2 are acquired from the detection unit <NUM> in each cycle illustrated in <FIG> or <FIG> (step <NUM>), the detection control unit <NUM> calculates an evaluation index V of the intensity signals A1, A2, A3, and A4 by V = f(A1, A2, A3, A4) by using a predetermined evaluation function f() (step <NUM>). The evaluation function f() is a function that calculates a magnitude of reflection due to an object in the vicinity of the display surface in front of the display surface from the intensity signals A1, A2, A3, and A4. As an example, a function that calculates maximum values of the intensity signals A1, A2, A3, and A4, a linear combination function for A1, A2, A3, and A4 (a × A1 + b × A2 + c × A3 + d × A4), and the like can be used as the evaluation function f().

The detection control unit calculates maximum values max (A1, A2, A3, A4) of the intensity signals A1, A2, A3, and A4 as MA (step <NUM>), investigates whether or not MA exceeds a predetermined threshold value Thmin (step <NUM>), returns the processing to step <NUM> as it is when the MA does not exceed the predetermined threshold value, and waits for the acquisition of the intensity signals A1, A2, A3, A4, E1, and E2 of the next cycle from the detection unit <NUM>. A minimum value with which MA is acquirable when the reflection due to the hand of the user occurs in the vicinity of the display surface in front of the display surface of the display <NUM> is used as the threshold value Thmin.

Meanwhile, when MA exceeds the predetermined threshold value Thmin (step <NUM>), the maximum values of the intensity signals E1 and E2 are calculated as ME (step <NUM>).

EY is calculated by EY = ME/MA (step <NUM>), and a threshold value Th is adjusted according to a value of EY (step <NUM>).

In step <NUM>, the threshold value Th is adjusted such that the threshold value Th becomes smaller when the EY is small than when the EY is large. More specifically, in step <NUM>, for example, the threshold value Th is set to a first value when EY is smaller than a predetermined value, and the threshold value Th is set to a second value larger than the first value when EY is not smaller than the predetermined value. Alternatively, the threshold value Th is set so as to become small as EY becomes small.

The detection control unit compares V calculated in step <NUM> with the threshold value Th (step <NUM>), returns the processing to step <NUM> when V is not larger than the threshold value Th, and waits for the acquisition of the intensity signals A1, A2, A3, A4, E1, and E2 from the detection unit <NUM>.

Meanwhile, when the evaluation index V is larger than the threshold value Th, the detection control unit detects the approach of the hand of the user to the display surface of the display <NUM>, and notifies the data processing device <NUM> of the approach of the hand of the user (step <NUM>).

The detection control unit returns the processing to step <NUM>, and waits for the acquisition of the intensity signals A1, A2, A3, A4, E1, and E2 of the next cycle from the detection unit <NUM>.

The proximity detection processing performed by the detection control unit <NUM> has been described above.

Here, as described above, E1 and E2 have relatively large values when the reflection due to the hand of the user occurs in the upper region of the display <NUM>, and have relatively small values when the reflection due to the hand of the user occurs in a lower region of the display <NUM>.

Meanwhile, the magnitude of MA indicates the magnitude of the reflection occurring due to the hand of the user in the vicinity of the display surface in front of the display surface of the display <NUM>.

Accordingly, when ME is smaller than MA, that is, when EY = ME/MA calculated in step <NUM> of the above-described proximity detection processing is small, it is possible to discriminate that the reflection due to the hand of the user occurs at a position not in the upper region of the display <NUM> but in the lower region of the display.

In step <NUM>, the threshold value Th is adjusted such that the threshold value Th becomes small in a case where the EY is small compared to a case where EY is large, and thus, the approach of the hand of the user can be detected for the lower portion of the display <NUM> at which a region in which the irradiation intensity of the infrared light becomes weak is formed by using a smaller threshold value Th compared to a case where the hand of the user is positioned in the upper region of the display <NUM>.

That is, since the approach of the hand of the user to the display surface of the display <NUM> can be detected in a form in which a detection sensitivity of the approach of the hand of the user to the lower portion of the display surface of the display <NUM> at which a region in which the irradiation intensity of the infrared light becomes weak is formed is higher than a detection sensitivity of the hand of the user to another portion of the display surface of the display <NUM>, the approach of the hand of the user to the lower portion can also be satisfactorily detected for the lower portion of the display <NUM> at which the irradiation intensity of the infrared light becomes weak is formed. When the detection sensitivity of the hand of the user is uniformly increased for portions other than the lower portion of the display surface of the display <NUM>, erroneous detection of detecting the approach of the hand of the user to the display surface occurs even when the hand of the user is far from the display surface of the display <NUM>. However, according to the present embodiment, the occurrence of such erroneous detection is suppressed.

Accordingly, the approach of the hand of the user can be satisfactorily detected in the entire region of the display surface of the display <NUM>.

Incidentally, although it has been described in the proximity detection processing that the maximum values of the intensity signals A1, A2, A3, and A4 are used as the evaluation index MA, another value may be used as the evaluation index MA as long as this value indicates degrees of the magnitudes of the reflection light detected in the PD <NUM> and the PD <NUM>. Although it has been described in the proximity detection processing that the maximum values of the intensity signals E1 and E2 are used as the evaluation index ME, another value may be used as the evaluation index ME as long as this value indicates degrees of the magnitudes of the reflection light detected in the PD <NUM> when only the LED <NUM> is turned on and the magnitude of the reflection light detected in the PD <NUM> when only the LED <NUM> is turned on. Although it has been described in the proximity detection processing that ME/MA is used as EY, another value may be used as EY as long as this value is an index value having an approximate correlation with whether a detected object is present at an upper portion or a lower portion of a display region.

Although it has been described in the embodiments that four infrared LEDs of the LED <NUM>, the LED <NUM>, the LED <NUM>, and the LED <NUM> and two photodiodes of the PD <NUM> and the PD <NUM> are used, the number of infrared LEDs may be four or more, and the photodiodes may be other than two.

However, in this case, for one or a plurality of relatively far infrared LEDs, the intensity signal detected by the photodiode relatively far from the turned-on infrared LED when the infrared LED is turned on is used in order to detect whether or not the hand of the user is positioned in the upper region of the display <NUM> instead of the intensity signals E1 and E2.

That is, for example, as illustrated in <FIG>, when six infrared LEDs and three photodiodes of the LED <NUM>, the PD <NUM>, the LED <NUM>, the LED <NUM>, the PD <NUM>, the LED <NUM>, the LED <NUM>, the PD <NUM>, and the LED <NUM> are arranged from left to right in the described order, it is detected whether or not the hand of the user is positioned in the upper region of the display <NUM> according to the magnitude of the intensity signal detected by the PD <NUM> when only the LED <NUM> is turned on and the intensity signal detected by the PD <NUM> when only the LED <NUM> is turned on.

Alternatively, for example, it is detected whether or not the hand of the user is positioned in the upper region of the display <NUM> according to the magnitude of the intensity signal detected by the PD <NUM> when only the LED <NUM> is turned on and the intensity signal detected by the PD <NUM> when only the LED <NUM> is turned on.

Alternatively, for example, it is detected whether or not the hand of the user is positioned in the upper region of the display <NUM> according to the magnitudes of the intensity signal detected by the PD <NUM> when only the LED <NUM> or the LED <NUM> is turned on or the intensity signal detected by the PD <NUM> when only the LED <NUM> or the LED <NUM> is turned on.

Claim 1:
A proximity detection device (<NUM>) configured to detect approach of a user to a display surface of a display (<NUM>), the proximity detection device (<NUM>) comprising:
a plurality of infrared light sources that is arranged outside and along a first side which is one side of the display surface of the display (<NUM>), and configured to emit infrared light passing through an area in front of the display surface diagonally;
a plurality of photodetectors each arranged between two infrared light sources along the first side of the display surface;
a proximity detection unit configured to detect the approach of the user to the display surface when an intensity which is detected by the photodetector corresponding to the infrared light source according to a predetermined positional correspondence and an intensity of reflection light of the infrared light emitted by the infrared light source is used as a first detection reflection intensity of emission light of the infrared light source for each of the plurality of infrared light sources and the intensity of the reflection light of the infrared light indicated by the first detection reflection intensity of the emission light of each infrared light source exceeds a set threshold value; and
a threshold value setting unit configured to set a threshold value to the proximity detection unit such that the threshold value changes depending on an evaluation value calculated according to a predetermined evaluation function from each second detection reflection intensity and each first detection reflection intensity by using, as target infrared light sources, one or a plurality of infrared light sources of the plurality of infrared light sources and using, as second detection reflection intensities of emission light of the target infrared light sources, intensities which are intensities of reflection light of infrared light emitted by the target infrared light sources and are detected by the photodetectors further from the target infrared light sources than the photodetectors corresponding to the infrared light sources which are the target infrared light sources according to the correspondence for each target infrared light sources.