JP2017111545A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of detecting contact or approach of an object without depending on an external light.SOLUTION: A display device comprises a display part, a control part and a detection part. The display part comprises plural light emission semiconductor elements comprising respectively, a first light emission part and a second light emission part in which a light emission wavelength is shorter than that in the first light emission part. The control part controls light emission of the light emission semiconductor elements. The detection part detects contact or approach between the display part and an object, based on photovoltaic generated on the first light emission parts when a light emitted from the second light emission parts and reflected on the object enters the first light emission parts, in a state in which the object approaches or contacts the display part. The control part causes the first light emission parts to pulse putting the light out during pulse lighting of the second light emission parts, when the light emission semiconductor element emits a light in a manner in which light emission of the first light emission parts is visually recognized and light emission of the second light emission parts is not visually recognized.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device that can detect contact or approach with an object.

  Light-emitting semiconductor elements such as light-emitting diodes (LEDs) and laser diodes (LDs) are used as light sources for display devices from the standpoints of miniaturization, low power consumption, saturation, vibration resistance, and repeated on / off durability. Has been. In particular, in a display unit of a display device, an LED display in which a plurality of LEDs are arranged in a two-dimensional matrix is used for a full-color display, an electric bulletin board, and the like.

  Further, it is known that an LED can be used as an optical sensor by utilizing a characteristic that a photovoltaic power is generated by receiving light. It has been proposed to use an LED display as a display device with a sensor function by using the characteristics of the LED (see, for example, Patent Document 1).

  In the display device with a sensor function described in Patent Document 1, a plurality of LEDs are arranged in a two-dimensional matrix. Since the light emitting unit of the LED cannot function as an optical sensor in a light emitting state, in the display device, each LED is switched to a lighting mode or a sensor mode. The LED in the lighting mode emits light, but cannot detect light. On the other hand, the sensor mode LED can detect light but cannot emit light. For this reason, the sensor mode LED detects light from the outside. For example, the display device (display for handwriting input) described in Patent Document 1 detects the contact of an object by detecting a decrease in the amount of incident light when the object (for example, a user's finger) contacts the LED. doing.

  On the other hand, although it is not a display device but a detection device, an optical sensor that can detect contact or approach of an object using one LED without depending on external light has been proposed (Patent Document 2). ).

JP 2007-206449 A JP 2006-093450 A

  As described above, in the display device with a sensor function described in Patent Document 1, since the contact detection operation depends on external light, it is possible to appropriately detect contact of an object in an environment where there is almost no external light. Can not.

  The present invention has been made in view of this point, and an object thereof is to provide a display device that can detect contact or approach of an object without depending on external light.

  The inventor configures a display unit by arranging light emitting semiconductor elements including a first light emitting unit and a second light emitting unit having different emission wavelengths as light sources, and emits light from the second light emitting unit in each light emitting semiconductor element. The present inventors have found that the above-mentioned problem can be solved by detecting the photovoltaic force generated in the first light-emitting part when the light reflected by the object is incident on the first light-emitting part, and completed the present invention by further study. .

That is, the present invention relates to the following display device.
[1] A display device that can detect contact or approach of an object, and includes a first light emitting unit and a second light emitting unit having a light emitting wavelength shorter than that of the first light emitting unit. Are arranged, a control unit for controlling light emission of the light emitting semiconductor element, and the object is emitted from the second light emitting unit in a state of being in contact with or close to the display unit, and the target A detection unit for detecting contact or approach between the display unit and the object based on a photovoltaic force generated in the first light-emitting unit when light reflected by the object enters the first light-emitting unit; When the light emitting semiconductor element emits light so that the light emission of the first light emitting unit is visually recognized and the light emission of the second light emitting unit is not visually recognized, the control unit includes the second light emitting unit. During the pulse lighting When the light emitting part is turned off and the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting part is visually recognized and the light emission of the first light emitting part is not visually recognized, the second light emitting part is turned on. At the same time, when the first light emitting unit is turned off and the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit and the second light emitting unit is visually recognized, the second light emitting unit is turned on. When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit and the second light emitting unit is not visually recognized, the first light emitting unit is turned off, and the first light emitting unit is turned off. A display device for lighting the second light emitting unit in pulses.
[2] The detection unit includes a first photovoltaic power generated in the first light emitting unit by light incident on the first light emitting unit in a state where the object is not in contact with or close to the display unit, and the target The difference value of the second photovoltaic power generated in the first light emitting unit by the light incident on the first light emitting unit in a state where an object is in contact with or close to the display unit, and the threshold voltage stored in the detection unit in advance The display device according to [1], wherein contact or approach between the display unit and the object is detected based on the above.
[3] The detection unit is based on a digital signal obtained by A / D conversion of an analog signal indicating the magnitude of the photovoltaic power corresponding to the intensity of light incident on the first light emitting unit. The display device according to [2], wherein the first photovoltaic power and the second photovoltaic power are measured.
[4] The control unit, when turning off the pulse of the first light emitting unit, turns off the first light emitting unit with a pulse width of 1 microsecond or less, according to any one of [1] to [3]. The display device described in 1.
[5] The control unit causes the second light emitting unit to pulse-light with a pulse width of 1 microsecond or less when the second light-emitting unit is pulse-lit. Any one of [1] to [4] The display device described in 1.
[6] The light emitting semiconductor element further includes a third light emitting unit having a light emission wavelength shorter than that of the second light emitting unit, and the control unit visually recognizes light emitted from the first light emitting unit, and the second light emitting unit. When the light emitting semiconductor element is caused to emit light so that the light emission of the third light emitting unit is not visually recognized, the first light emitting unit is turned off and the first light emitting unit is pulse-lit while the first light emitting unit is turned on. In the case where the light emitting part is turned off, the light emitting semiconductor element is caused to emit light so that light emission of the second light emitting part is visually recognized and light emission of the first light emitting part and the third light emitting part is not visually recognized. The two light emitting parts are turned on, the first light emitting part and the third light emitting part are turned off, the light emission of the third light emitting part is visually recognized, and the light emission of the first light emitting part and the second light emitting part is visually recognized. So that the light emitting half When the body element emits light, the first light emitting unit is turned off and the third light emitting unit is turned on, and the second light emitting unit is turned on in pulses, and the first light emitting unit and the second light emitting unit are turned on. In the case where the light emitting semiconductor element is caused to emit light so that the light emission of the third light emitting part is not visually recognized, the second light emitting part is turned on and the third light emitting part is turned off. When the first light emitting unit is turned off, the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting unit and the third light emitting unit is visually recognized and the light emission of the first light emitting unit is not visually recognized. The second light emitting unit and the third light emitting unit are turned on and the first light emitting unit is turned off, the light emission of the first light emitting unit and the third light emitting unit is visually recognized, and the second light emitting unit The luminescence is not visible When the light emitting semiconductor element is caused to emit light, the third light emitting unit is turned on, and the first light emitting unit is turned off while the second light emitting unit is turned on, so that the first light emitting unit is turned off. When the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting unit and the third light emitting unit is visually recognized, the second light emitting unit and the third light emitting unit are turned on and the first light emitting unit is turned on. When the light emitting unit is turned off and the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit, the second light emitting unit, and the third light emitting unit is not visually recognized, the first light emitting unit and the first light emitting unit The display device according to any one of [1] to [5], wherein the three light emitting units are turned off and the second light emitting unit is pulse-lit.
[7] The light emitting semiconductor element further includes a third light emitting unit having a light emission wavelength shorter than that of the second light emitting unit, and the control unit recognizes light emitted from the first light emitting unit, and the second light emitting unit. When the light emitting semiconductor element is caused to emit light so that the light emission of the third light emitting unit is not visually recognized, the first light emitting unit is turned off and the first light emitting unit is pulse-lit while the first light emitting unit is turned on. In the case where the light emitting part is turned off, the light emitting semiconductor element is caused to emit light so that light emission of the second light emitting part is visually recognized and light emission of the first light emitting part and the third light emitting part is not visually recognized. The two light emitting parts are turned on, the first light emitting part and the third light emitting part are turned off, the light emission of the third light emitting part is visually recognized, and the light emission of the first light emitting part and the second light emitting part is visually recognized. So that the light emitting half When the body element emits light, the first light emitting unit is turned off, and the third light emitting unit is turned off while the second light emitting unit is turned on in pulses, so that the first light emitting unit and the first light emitting unit are turned off. When the light emitting semiconductor element is caused to emit light so that the light emission of the two light emitting parts is visible and the light emission of the third light emitting part is not visually recognized, the second light emitting part is turned on and the third light emitting part is turned off. In addition, the first light emitting unit is pulse-extinguished, and the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting unit and the third light emitting unit is visually recognized and the light emission of the first light emitting unit is not visually recognized. In this case, the second light-emitting unit is turned on and the first light-emitting unit is turned off, and the third light-emitting unit is turned off. And said In the case where the light emitting semiconductor element emits light so that the light emission of the two light emitting units is not visually recognized, the first light emitting unit and the third light emitting unit are turned off while the second light emitting unit is turned on in pulses. When the light emitting semiconductor element is caused to emit light so that light emitted from the first light emitting unit, the second light emitting unit, and the third light emitting unit is visually recognized, the second light emitting unit is turned on and the first light emitting unit is turned on. When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit, the second light emitting unit, and the third light emitting unit is not visually recognized, the first light emitting unit, the third light emitting unit, and the third light emitting unit are turned off. The display device according to any one of [1] to [5], wherein the light emitting unit and the third light emitting unit are turned off, and the second light emitting unit is turned on in pulses.
[8] The display device according to any one of [1] to [5], wherein an emission color of the first light emitting unit is red, and an emission color of the second light emitting unit is green.
[9] The emission color of the first light emitting unit is red, the emission color of the second light emitting unit is green, and the emission color of the third light emitting unit is blue, [6] or [ 7].

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus which can detect the contact or approach of a target object without depending on external light can be provided.

FIG. 1 is a block diagram showing a configuration of a display device according to an embodiment of the present invention. FIG. 2 is a schematic diagram for illustrating a configuration of an LED. 3A and 3B are graphs showing emission spectra and light reception spectra of the first light emitting unit and the second light emitting unit. 4A to 4C are timing charts of the light emitting units in the light emission patterns 1 to 3. 5A to 5C are timing charts of the light emitting units in the light emission patterns 4 to 6, respectively. 6A and 6B are timing charts of the light emitting units in the light emission patterns 7 and 8, respectively. FIG. 7 is a graph showing the relationship between the pulse signal input to the second light emitting unit by the control unit and the light reception signal received by the first light emitting unit and output to the contact detection unit in the contact state. 8A and 8B are graphs for explaining the first contact detection operation. 9A and 9B are graphs for explaining the second contact detection operation. FIG. 10 is a block diagram illustrating a configuration of a display device according to a modification. 11A to 11D are timing charts of the light emitting units in the light emission patterns 1 'to 4'. FIG. 12 is a schematic diagram for explaining an aspect of detecting the approach between the display unit and the object. FIG. 13 is a timing chart of the light emitting unit showing an example of another light emission pattern of the display device.

  Hereinafter, an embodiment of the present invention will be described in detail. Here, an example in which the display device according to the present invention is applied to a multi-color LED display using a light emitting diode (LED) as a light emitting semiconductor element will be described. The display device according to the present embodiment can detect contact between the display unit and the object. The object is appropriately selected according to the use of the display device, and is, for example, a finger or a touch pen.

[Configuration of display device]
FIG. 1 is a block diagram showing a configuration of display device 100 according to the present embodiment. The display device 100 includes a display control unit 140, a lighting control unit 150, a display unit 130, and a light reception detection unit 160. The display control unit 140 and the lighting control unit 150 function as the control unit 110 that controls the light emission of the LED 131 in cooperation. The display control unit 140 and the light reception detection unit 160 function as a contact detection unit (detection unit) 120 for detecting contact between the display unit 130 and the object 10 in cooperation. Although not particularly illustrated, in the display unit 130 of the display device 100 according to the present embodiment, a plurality of LEDs 131 are arranged in a two-dimensional matrix.

  The display control unit 140 controls the lighting control unit 150 to display display information included in the external signal 20 on the display unit 130 while detecting contact between the display unit 130 and the object 10. The display control unit 140 is electrically connected to the lighting control unit 150 and the light reception detection unit 160. The display control unit 140 outputs a lighting control signal for controlling the lighting control unit 150 to the lighting control unit 150 in accordance with the content of the external signal 20 input from an external source. Further, the display control unit 140 detects contact between the display unit 130 and the target object 10 based on the information output from the light reception detection unit 160. Although details will be described later, the display control unit 140 may store in advance information for determining whether or not the display unit 130 and the object 10 are in contact with each other. The display control unit 140 is a semiconductor device including, for example, an input circuit, an output circuit, an arithmetic circuit, a control circuit, and a memory circuit.

  The external signal 20 includes display information displayed on the display unit 130. The display information is information relating to still images and moving images including, for example, characters and graphics.

  The lighting control unit 150 controls light emission of the plurality of LEDs 131. The lighting control unit 150 is electrically connected to the display control unit 140 and the display unit 130 (more specifically, the light emitting unit 132 of each LED 131). The lighting control unit 150 supplies power for driving the plurality of LEDs 131 to the light emitting unit 132 of each LED 131 based on the lighting control signal from the display control unit 140. Accordingly, the lighting control unit 150 turns on, turns on, turns off, or turns off the pulses of each LED 131. Thereby, the light emission timing, light emission color, light emission intensity, and the like of the LED 131 can be controlled.

  Here, in this specification, “lighting” means that the light emitting unit 132 is continuously turned on, and “pulse lighting” means that the light emitting unit 132 that is continuously turned off is given a predetermined signal by a pulse signal. It means lighting for a very short time at the timing. “Light off” refers to turning off the light emitting unit 132 continuously. “Pulse light off” refers to turning off the light emitting unit 132 that is continuously turned on at a predetermined timing by a pulse signal for a very short time. It means to make it. As will be described in detail later, pulse lighting is performed with a pulse width that cannot be recognized by the human eye, and pulse extinguishing is performed with a pulse width that cannot be recognized by the human eye. .

  From the viewpoint of reducing power consumption and extending the life of the LED 131, when the light emitting unit 132 is continuously lit, it is preferably lit by a dynamic lighting method. The lighting control unit 150 is a semiconductor device having, for example, an input circuit, an output circuit, a pulse signal generation circuit, and a dynamic control circuit.

  The display unit 130 displays an image formed by the plurality of LEDs 131 emitting light (or not emitting light). A plurality of LEDs 131 are arranged in a predetermined pattern on the display unit 130. The plurality of LEDs 131 may be covered with a cover plate or the like formed of transparent glass or resin.

  FIG. 2 is a schematic diagram for illustrating a configuration of the LED 131 included in the display device 100 according to the present embodiment. The LED 131 includes a plurality of light emitting units 132 having different emission wavelengths. Each light emitting unit 132 is driven by the power supplied from the lighting control unit 150 and emits light of a predetermined color. The number of light emitting units 132 and the light emission wavelength can be appropriately set according to the required light emission color. For example, from the viewpoint of enabling multi-color display, the LED 131 preferably includes a light emitting unit whose emission color is red, a light emission unit whose emission color is green, and a light emission unit whose emission color is blue. . As shown in FIGS. 1 and 2, the LED 131 according to the present embodiment includes a first light emitting unit 132R, a second light emitting unit 132G having a shorter emission wavelength than the first light emitting unit 132R, and a second light emitting unit 132G. A third light emitting unit 132B having a short emission wavelength. The emission color of the first light emitting unit 132R is red (center wavelength: 615 to 640 nm), the emission color of the second light emitting unit 132G is green (center wavelength: 520 to 545 nm), and the emission color of the third light emitting unit 132B. Is blue (center wavelength: 455 to 480 nm).

  In the LED 131 according to the present embodiment, the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B are all connected to the common terminal 133. The first light emitting unit 132R is further connected to the first terminal 134r, the second light emitting unit 132G is further connected to the second terminal 134g, and the third light emitting unit 132B is further connected to the third terminal 134b. The first light emitting unit 132R is driven by the power supplied from the lighting control unit 150 via the common terminal 133 and the first terminal 134r, and lights up. The second light emitting unit 132G is driven by the power supplied from the lighting control unit 150 via the common terminal 133 and the second terminal 134g, and lights up. The third light emitting unit 132B is driven by the power supplied from the lighting control unit 150 via the common terminal 133 and the third terminal 134b, and lights up.

  The first light emitting unit 132 </ b> R can be turned on (or turned off) by a signal output from the lighting control unit 150 while being electrically connected to the light receiving detection unit 160. However, as described later, the first light emitting unit 132R needs to be electrically disconnected from the lighting control unit 150 during light reception.

  Further, the number and arrangement of the LEDs 131 can be appropriately set according to the use of the display device 100. For example, the number of LEDs 131 can be appropriately set according to the size of the LED 131 itself, the size of the display unit 130, and the like. Examples of the arrangement of the LEDs 131 include a two-dimensional matrix shape, a staggered shape, a spiral shape, and a concentric shape.

  The light emitting unit 132 of the LED 131 cannot function as an optical sensor when it is lit (no photovoltaic power is generated). That is, the light emitting unit 132 that is lit is emitting light but cannot detect light. On the other hand, the light emitting unit 132 that is turned off can detect light but cannot emit light.

  Although details will be described later, in the display device 100 according to the present embodiment, of the three light emitting units 132, one of the light emitting units 132 is also used as an optical sensor (hereinafter simply referred to as “light emission also serving as an optical sensor”). Part)). The light emitting unit 132 also serving as an optical sensor receives light emitted from another light emitting unit 132 used as a light source (hereinafter also simply referred to as “light emitting unit serving as a light source for contact detection”). When light is incident on the light emitting unit 132 also serving as a photosensor, a photovoltaic force is generated. The light emitting unit 132 also serving as an optical sensor is electrically connected to the light receiving detection unit 160 via the common terminal 133 and the first terminal 134r, the second terminal 134g, or the third terminal 134b. The electric power is taken out by the light receiving detection unit 160.

  The light emitting unit 132 also serving as an optical sensor and the light emitting unit 132 also serving as a light source for contact detection are the light reception spectrum of the light emitting unit 132 also serving as an optical sensor, and the emission wavelength ( It is preferable that the light receiving efficiency is selected based on the relationship with the emission spectrum. Thereby, the contact between the display unit 130 and the object 10 can be detected with high accuracy. From the viewpoint of high light receiving efficiency and high photovoltaic power, the first light emitting unit 132R whose emission color is red is used as the light emitting unit 132 also serving as an optical sensor, and the light emitting unit 132 also serving as a light source for detecting contact is used. It is preferable to use the second light-emitting portion 132G whose emission color is green (see, for example, JP-A-2006-093450).

  FIG. 3A is a graph showing an emission spectrum and a light reception spectrum of the first light emitting unit 132R, and FIG. 3B is a graph showing an emission spectrum and a light reception spectrum of the second light emission unit 132G. In FIGS. 3A and 3B, the emission spectrum is indicated by a solid line, and the received light spectrum is indicated by a broken line. It turns out that the 2nd light emission part 132G light-emits with the light emission wavelength 500-600 nm (refer the continuous line of FIG. 3B). It turns out that the 1st light emission part 132R receives light with a wavelength of 500-650 nm (refer the broken line of Drawing 3A). Thus, the emission spectrum of the second light emitting unit 132G and the light reception spectrum of the first light emitting unit 132R overlap very well. Therefore, using the first light emitting unit 132R as the light emitting unit 132 also serving as the optical sensor and using the second light emitting unit 132G as the light emitting unit 132 serving as the light source for contact detection increases the light receiving efficiency and increases the light receiving efficiency. It is preferable from the viewpoint of obtaining photovoltaic power.

  As shown in FIG. 1 and FIG. 2, in the present embodiment, the light emitting portion 132 that also serves as an optical sensor is the first light emitting portion 132R, and the light emitting portion 132 that also serves as a light source for contact detection is the second light emitting portion. 132G. The first light emitting unit 132R is emitted from the second light emitting unit 132G and reflected by the object 10, light emitted from the second light emitting unit 132G and internally reflected on the surface of the LED 131, and the second light emitting unit 132G. The light that is emitted and directly reaches the first light emitting unit 132R is received.

  The light reception detection unit 160 generates a light reception signal indicating the magnitude of the photovoltaic power corresponding to the intensity of light incident on the light emitting unit 132 also serving as an optical sensor (in the present embodiment, the first light emitting unit 132R). The light reception detection unit 160 is electrically connected to the light emission unit 132 also serving as an optical sensor and the display control unit 140. The light reception detection unit 160 outputs the generated light reception signal to the display control unit 140. The light reception detection unit 160 is, for example, a semiconductor device having an input circuit, an output circuit, an amplifier circuit (described later), an A / D conversion circuit (described later), and a control circuit. As described above, in the display device 100 according to the present embodiment, the lighting control unit 150 controls the light emission of the LED 131. The lighting control unit 150 may output a signal having a peak voltage of 0 V to turn off each light emitting unit 132 or may turn off each light emitting unit 132 by being electrically disconnected. However, when the first light emitting unit 132R receives light, the lighting control unit 150 and the first light emitting unit 132R need to be electrically disconnected from each other.

  Although details will be described later, the display control unit 140 detects contact between the display unit 130 and the object 10 based on the light reception signal generated from the light reception detection unit 160. From the viewpoint of detecting the contact between the display unit 130 and the object 10 with higher accuracy, the light reception detection unit 160 is configured to amplify the generated light reception signal and an analog signal (the light reception signal) as a digital signal. It is preferable to have other circuits such as an A / D conversion circuit for converting the signal. In the present embodiment, the light reception detection unit 160 includes an A / D conversion circuit 165.

The display control unit 140 includes a first photovoltaic power V ₁ generated by light incident on the first light emitting unit 132R in a state where the object 10 is not in contact with the display unit 130 (hereinafter also simply referred to as “non-contact state”). , And a second photovoltaic voltage V ₂ generated by light incident on the first light emitting unit 132R in a state where the object 10 is in contact with the display unit 130 (hereinafter, also simply referred to as “contact state”), and a predetermined threshold voltage V Based on _th , a contact between the display unit 130 and the object 10 is detected (described later).

The first electromotive force _{V 1} in the non-contact state is released from the second light emitting unit 132G, and the light internally reflected by the surface of the LED 131 is emitted from the second light emitting unit 132G, the light reaching directly to the first light emitting portion 132R Is caused by being incident on the first light emitting unit 132R (see the broken line arrow in FIG. 1). In addition, in addition to the above-mentioned internally reflected light and directly reached light, the second photovoltaic power V ₂ in the contact state is further radiated from the second light emitting unit 132G and reflected by the object 10 is the first. This is caused by being incident on the light emitting unit 132R (see the broken line arrows and the solid line arrows in FIGS. 1 and 2). Thus, the second photovoltaic V _2, the light contributes fraction reflected by the object 10, than the first photovoltaic V ₁ increases.

[Operation of display device]
Next, the operation of the display device 100 will be described in detail. Display device 100 according to the present embodiment can display images on display unit 130 in multiple colors while detecting contact between display unit 130 and object 10. First, a display operation for performing multi-color display while detecting a contact between the display unit 130 and the object 10 will be described, and then the contact detection operation will be described in more detail.

(Display operation)
As described above, the control unit 110 (the display control unit 140 and the lighting control unit 150) controls the light emission timing and the light emission color of the LED 131. When one LED 131 has three light emitting units (the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B), the light is emitted from the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B. The emission color of each LED 131 can be adjusted by adjusting the ratio of the emitted light intensity. In this way, the display device 100 can be used as a full color display. In the present embodiment, the controller 110 causes each LED 131 to emit light with the following eight light emission patterns 1 to 8. Thereby, display device 100 according to the present embodiment can express eight colors (multicolor) of red, green, blue, yellow, light blue, purple, white, and black (when turned off) by LED 131.

  4A to C show timing charts of the light emitting unit 132 in the light emission patterns 1 to 3, FIGS. 5A to 5C show timing charts of the light emitting unit 132 in the light emission patterns 4 to 6, and FIGS. 6A and 6B show the light emission patterns. The timing chart of the light emission part 132 in 7 and 8 is shown.

1) Light emission pattern 1
When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R is visible and the light emission of the second light emitting unit 132G and the third light emitting unit 132B is not visually recognized, as shown in FIG. 4A, the third light emitting unit 132B is turned off, and the first light emitting unit 132R is turned off while the second light emitting unit 132G is turned on in pulses. As a result, the LED 131 is lit red.

Control unit 110, the time _{t 2} except for pulse off the first light emitting portion 132R by a pulse width _{t 1} lights the first light emitting portion 132R. At this time, the control unit 110, a pulse width t ₁ invisible that the first light emitting portion 132R by the afterimage effect is turned off, thereby the first light emitting portion 132R pulsed off. For this reason, the first light emitting unit 132R is visually recognized as being continuously lit.

The control unit 110, the time _{t 2} except for pulse lighting of the second light emitting unit 132G in pulse width _{t 1} is turns off the second light emitting unit 132G. At this time, the control unit 110, a pulse width _{t 1} of the second light emitting portion 132G is not visible that the lights, the second light emitting unit 132G is pulse lighting. For this reason, the second light emitting unit 132G is visually recognized as being continuously turned off.

  Furthermore, the control unit 110 continuously turns off the third light emitting unit 132B. For this reason, the 3rd light emission part 132B is visually recognized as having light-extinguished continuously.

  In the light emission pattern 1, the control unit 110 turns on the second light emitting unit 132 </ b> G in synchronization with the light extinction of the first light emitting unit 132 </ b> R. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, in the light emission pattern 1, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

2) Light emission pattern 2
When the LED 131 is caused to emit light so that the light emission of the second light emitting unit 132G is visually recognized and the light emission of the first light emitting unit 132R and the third light emitting unit 132B is not visually recognized, as shown in FIG. 4B, the second light emitting unit While turning on 132G, the 1st light emission part 132R and the 3rd light emission part 132B are light-extinguished. As a result, the LED 131 is lit green.

  The control unit 110 turns off the first light emitting unit 132R continuously. Therefore, the first light emitting unit 132R is visually recognized as being continuously turned off.

  In addition, the control unit 110 continuously turns on the second light emitting unit 132G. For this reason, the 2nd light emission part 132G is visually recognized so that it may light continuously.

  Furthermore, the control unit 110 continuously turns off the third light emitting unit 132B. For this reason, the 3rd light emission part 132B is visually recognized as having light-extinguished continuously.

  In the light emission pattern 2, the control unit 110 turns off the first light emitting unit 132R and turns on the second light emitting unit 132G. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 2, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

3) Light emission pattern 3
When the LED 131 is caused to emit light so that the light emission of the third light emitting unit 132B is visually recognized and the light emission of the first light emitting unit 132R and the second light emitting unit 132G is not visually recognized, as shown in FIG. 4C, the first light emitting unit 132R is turned off and the third light emitting unit 132B is turned off while the second light emitting unit 132G is turned on in pulses. Thereby, the LED 131 is lit blue.

  The control unit 110 turns off the first light emitting unit 132R continuously. Therefore, the first light emitting unit 132R is visually recognized as being continuously turned off.

The control unit 110, the time _{t 2} except for pulse lighting of the second light emitting unit 132G in pulse width _{t 1} is turns off the second light emitting unit 132G. At this time, the control unit 110, a pulse width _{t 1} of the second light emitting portion 132G is not visible that the lights, the second light emitting unit 132G is pulse lighting. For this reason, the second light emitting unit 132G is visually recognized as being continuously turned off.

Further, the control unit 110, the time _{t 2} except for the pulse turns off the third light emitting portion 132B by a pulse width _{t 1} lights the third light emitting portion 132B. At this time, the control unit 110, a pulse width _{t 1} of the third light emitting portion 132B is not visible that off, the third light emitting unit 132B is pulse off. For this reason, the 3rd light emission part 132B is visually recognized so that it may light continuously.

  In the light emission pattern 3, the control unit 110 turns off the first light emitting unit 132R and turns on the second light emitting unit 132G in pulses. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 3, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

4) Light emission pattern 4
When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R and the second light emitting unit 132G is visible and the light emission of the third light emitting unit 132B is not visually recognized, as shown in FIG. 5A, the second light emitting unit 132G is turned on, the third light emitting unit 132B is turned off, and the first light emitting unit 132R is turned off. As a result, the LED 131 is lit yellow.

Control unit 110, the time _{t 2} except for pulse off the first light emitting portion 132R by a pulse width _{t 1} lights the first light emitting portion 132R. At this time, the control unit 110, a pulse width t ₁ invisible that the first light emitting portion 132R by the afterimage effect is turned off, thereby the first light emitting portion 132R pulsed off. For this reason, the first light emitting unit 132R is visually recognized as being continuously lit.

  In addition, the control unit 110 continuously turns on the second light emitting unit 132G. For this reason, the 2nd light emission part 132G is visually recognized so that it may light continuously.

  Furthermore, the control unit 110 continuously turns off the third light emitting unit 132B. For this reason, the 3rd light emission part 132B is visually recognized as having light-extinguished continuously.

  In the light emission pattern 4, the control unit 110 turns on the second light emitting unit 132G and turns off the first light emitting unit 132R in pulses. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 4, the display device 100 can display an image on the display unit 130 while detecting contact between the display unit 130 and the object 10.

5) Light emission pattern 5
When the LED 131 is caused to emit light so that the light emission of the second light emitting unit 132G and the third light emitting unit 132B is visually recognized and the light emission of the first light emitting unit 132R is not visually recognized, as shown in FIG. 5B, the second light emitting unit 132G is turned on, the first light emitting unit 132R is turned off, and the third light emitting unit 132B is turned off in pulses. As a result, the LED 131 is light blue.

  The control unit 110 turns off the first light emitting unit 132R continuously. Therefore, the first light emitting unit 132R is visually recognized as being continuously turned off.

  In addition, the control unit 110 continuously turns on the second light emitting unit 132G. For this reason, the 2nd light emission part 132G is visually recognized so that it may light continuously.

Further, the control unit 110, the time _{t 2} except for the pulse turns off the third light emitting portion 132B by a pulse width _{t 1} lights the third light emitting portion 132B. At this time, the control unit 110, a pulse width _{t 1} of the third light emitting portion 132B is not visible that off, the third light emitting unit 132B is pulse off. For this reason, the 3rd light emission part 132B is visually recognized so that it may light continuously.

  In the light emission pattern 5, the control unit 110 turns on the second light emitting unit 132G and turns off the first light emitting unit 132R. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 5, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

6) Light emission pattern 6
When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R and the third light emitting unit 132B is visually recognized and the light emission of the second light emitting unit 132G is not visually recognized, as shown in FIG. 5C, the second light emitting unit The first light emitting unit 132R and the third light emitting unit 132B are turned off in pulses while the 132G is turned on in pulses. Thereby, the LED 131 is lit purple.

Control unit 110, the time _{t 2} except for pulse off the first light emitting portion 132R by a pulse width _{t 1} lights the first light emitting portion 132R. At this time, the control unit 110, a pulse width t ₁ invisible that the first light emitting portion 132R by the afterimage effect is turned off, thereby the first light emitting portion 132R pulsed off. For this reason, the first light emitting unit 132R is visually recognized as being continuously lit.

The control unit 110, the time _{t 2} except for pulse lighting of the second light emitting unit 132G in pulse width _{t 1} is turns off the second light emitting unit 132G. At this time, the control unit 110, a pulse width _{t 1} of the second light emitting portion 132G is not visible that the lights, the second light emitting unit 132G is pulse lighting. For this reason, the second light emitting unit 132G is visually recognized as being continuously turned off.

Further, the control unit 110, the time _{t 2} except for the pulse turns off the third light emitting portion 132B by a pulse width _{t 1} lights the third light emitting portion 132B. At this time, the control unit 110, a pulse width t ₁ which can not visually recognize that the third light-emitting portion 132B by the afterimage effect is turned off, causing the third light emitting unit 132B is pulse off. For this reason, the 3rd light emission part 132B is visually recognized so that it may light continuously.

  In the light emission pattern 6, the control unit 110 turns on the second light emitting unit 132 </ b> G in synchronization with the light extinction of the first light emitting unit 132 </ b> R. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 6, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

7) Light emission pattern 7
When the LED 131 is caused to emit light so that the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B can be visually recognized, the second light emitting unit 132G is turned on as shown in FIG. 6A. The first light emitting unit 132R and the third light emitting unit 132B are turned off in pulses. As a result, the LED 131 is lit white.

Control unit 110, the time _{t 2} except for pulse off the first light emitting portion 132R by a pulse width _{t 1} lights the first light emitting portion 132R. At this time, the control unit 110, a pulse width t ₁ invisible that the first light emitting portion 132R by the afterimage effect is turned off, thereby the first light emitting portion 132R pulsed off. For this reason, the first light emitting unit 132R is visually recognized as being continuously lit.

  In addition, the control unit 110 continuously turns on the second light emitting unit 132G. For this reason, the 2nd light emission part 132G is visually recognized so that it may light continuously.

Further, the control unit 110, the time _{t 2} except for the pulse turns off the third light emitting portion 132B by a pulse width _{t 1} lights the third light emitting portion 132B. At this time, the control unit 110, a pulse width t ₁ which can not visually recognize that the third light-emitting portion 132B by the afterimage effect is turned off, causing the third light emitting unit 132B is pulse off. For this reason, the 3rd light emission part 132B is visually recognized so that it may light continuously.

  In the light emission pattern 7, the control unit 110 turns on the second light emitting unit 132G and turns off the first light emitting unit 132R in pulses. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 7, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

8) Light emission pattern 8
When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B is not visually recognized, as shown in FIG. 6B, the first light emitting unit 132R and the third light emitting unit 132B is turned off and the second light emitting unit 132G is turned on in pulses. As a result, the LED 131 is black (lights off).

  The control unit 110 turns off the first light emitting unit 132R continuously. Therefore, the first light emitting unit 132R is visually recognized as being continuously turned off.

The control unit 110, the time _{t 2} except for pulse lighting of the second light emitting unit 132G in pulse width _{t 1} is turns off the second light emitting unit 132G. At this time, the control unit 110, a pulse width _{t 1} of the second light emitting portion 132G is not visible that the lights, the second light emitting unit 132G is pulse lighting. For this reason, the second light emitting unit 132G is visually recognized as being continuously turned off.

  Furthermore, the control unit 110 continuously turns off the third light emitting unit 132B. For this reason, the 3rd light emission part 132B is visually recognized as having light-extinguished continuously.

  In the light emission pattern 8, the control unit 110 turns off the first light emitting unit 132R and turns on the second light emitting unit 132G in pulses. Thereby, in the contact state, the first light emitting unit 132R can detect the light emitted from the second light emitting unit 132G and reflected by the object 10. For this reason, also in the light emission pattern 8, the display apparatus 100 can display an image on the display part 130, detecting the contact with the display part 130 and the target object 10. FIG.

  As described above, the display device 100 according to the present embodiment can be used as a multi-color display having a function of detecting contact between the display unit 130 and the object 10.

  In the light emission patterns 1, 3 to 7, the control unit 110 switches the first light emitting unit 132R, the third light emitting unit 132B, or both so that the first light emitting unit 132R, the third light emitting unit 132B, or both of them cannot be visually recognized. Turn off the pulse. At this time, the control unit 110 preferably turns off the first light emitting unit 132R, the third light emitting unit 132B, or both with a pulse width of 1 microsecond or less. Further, from the viewpoint of sufficiently securing the time required for the rising of the light reception signal in the first light emitting unit 132R, the control unit 110 preferably turns off the first light emitting unit 132R with a pulse width of 10 nanoseconds or more.

  Moreover, in the light emission patterns 1, 3, 6, and 8, the control part 110 light-pulses so that lighting of the 2nd light emission part 132G cannot be visually recognized. At this time, it is preferable that the control unit 110 turns on the second light emitting unit 132G with a pulse width of 1 microsecond or less. In addition, from the viewpoint of sufficiently securing the time required from the input of the pulse signal to the light emission of the second light emitting unit 132G and the time required for the rise of the light reception signal in the first light emitting unit 132R, the control unit 110 includes the first It is preferable that the two light-emitting portions 132G are pulse-lit with a pulse width of 10 nanoseconds or more. The pulse width of the second light emitting unit 132G can be appropriately adjusted according to other conditions of the display device 100. For example, the lighting of the second light emitting unit 132G can be made difficult to be visually recognized by lengthening the turn-off time or suppressing the peak voltage of the pulse signal. Further, the lighting of the second light emitting unit 132G is not easily seen by providing a diffusion plate in the display unit 130 or designing the surface structure of the LED 131 so that the amount of light internally reflected on the surface is increased. can do. Thus, even if the pulse width is long, it can be adjusted so that the lighting of the second light emitting unit 132G cannot be visually recognized by devising other conditions.

(Contact detection operation)
Next, the contact detection operation between the display unit 130 and the target object 10 in the display device 100 according to the present embodiment will be described in more detail. FIG. 7 illustrates a pulse signal input to the second light emitting unit 132G by the control unit 110 and a light reception signal received by the first light emitting unit 132R and output to the contact detection unit 120 (display control unit 140) in the contact state. Shows the relationship. Here, the pulse width t ₁ is so that the pulse period T to pulse signal of 1 microsecond is 5 ms, and that input to the second light emitting unit 132G. As shown in FIG. 7, it can be seen that the lighting of the second light emitting unit 132G and the light reception by the first light emitting unit 132R occur at substantially the same timing under the above conditions. From this result, if the first light emitting unit 132R is turned off while the second light emitting unit 132G is turned on with a pulse width t ₁ of about 1 microsecond, the display unit 130 and the object 10 It can be seen that the contact can be sufficiently detected.

In addition, as described above, in the present embodiment, the display unit 130 is based on the first electromotive force V ₁ in the non-contact state, the second photovoltaic force V ₂ in the contact state, and the predetermined threshold voltage V _th. And whether or not the object 10 is in contact. Hereinafter, without A / D conversion of the received light signal, and the first electromotive force V ₁ and second electromotive force V _2, the contact between the display unit 130 and the object 10 by comparing the threshold voltage V _th In the case of detection (hereinafter referred to as “first contact detection operation”), A / D conversion of the received light signal is performed, and the difference value V _diff between the first electromotive force V ₁ and the second electromotive force V ₂ is set to a threshold value. When the contact between the display unit 130 and the object 10 is detected by comparing the voltage _Vth (hereinafter referred to as “second contact detection operation”), the received light signal is A / D converted, and the first When the contact between the display unit 130 and the object 10 is detected by comparing the first electromotive force V ₁ and the second electromotive force V ₂ with the threshold voltage V _th (hereinafter referred to as “third contact detection operation”). ).

The first electromotive force V ₁ was, for a reference to the second electromotive force V _2, measured beforehand at a predetermined period, may be stored in advance in the contact detection unit 120 (display control unit 140). The threshold voltage V _th is determined by the characteristics of the elements included in the contact detection unit 120 in the first contact detection operation, and is stored in the contact detection unit 120 in advance in the second contact detection operation and the third contact detection operation. Is an arbitrary value.

First, the first contact detection operation will be described. 8A and 8B are graphs for explaining the first contact detection operation. In the first contact detecting operation, a first electromotive force _{V 1} and second electromotive force _{V 2,} is compared with the threshold voltage _{V th.} That is, as shown in FIG. 8A, when the threshold voltage V _th is larger than the first electromotive force V ₁ in the non-contact state and is equal to or smaller than the second electromotive force V ₂ in the contact state (V ₁ < For V _th ≦ V ₂ ), the contact between the display unit 130 and the target object 10 can be detected by comparing the photovoltaic force generated in the first light emitting unit 132R with the threshold voltage V _th .

For example, if the photovoltaic voltage V generated in the first light emitting unit 132R is smaller than the threshold voltage _Vth (V < _Vth ), it can be determined that the display unit 130 and the object 10 are not in contact. Further, if the photovoltaic voltage V generated in the first light emitting unit 132R is equal to or larger than the threshold voltage _Vth (V ≧ _Vth ), it is determined that the display unit 130 and the object 10 are in contact with each other. be able to.

However, the threshold voltage V _th is determined by the characteristics of elements included in the contact detection unit 120 (more specifically, the light reception detection unit 160 that generates a light reception signal). Therefore, depending on the characteristics of the elements included in the light receiving detection unit 160, the influence of the external environment such as external light and temperature (described later), and individual differences in LED characteristics (described later), as shown in FIG. In some cases, the first electromotive force V ₁ in the state is equal to or greater than the threshold voltage V _th (V _th ≦ V ₁ <V ₂ ). In this case, since the photovoltaic voltage V generated in the first light emitting unit 132R is always equal to or larger than the threshold voltage _Vth ( _Vth ≦ V), the display unit 130 and the object 10 are actually in contact with each other. Even if it is not, it will be judged that it is always in contact.

For example, when the light receiving detector 160 is TTL, the threshold voltage _Vth is about 2.0 V (high level) and about 0.8 V (low level). When the first light emitting unit 132R whose emission color is red is used as the light emitting unit 132 also serving as the optical sensor, and the second light emitting unit 132G whose emission color is green is used as the light emitting unit 132 also serving as the light source for contact detection a first electromotive force _{V 1} in the non-contact state is about 1.2V. That is, the contact detection unit 120 determines that the display unit 130 and the object 10 are always in contact with each other even if they are not actually in contact with each other.

  As described above, in the first contact detection operation, whether the display unit 130 and the object 10 are in contact with each other due to the characteristics of the elements included in the contact detection unit 120, the influence of the external environment, and individual differences in LED characteristics. It may not be possible to accurately detect whether or not.

On the other hand, in the second contact detection operation, the contact detection unit 120 compares the difference value V _diff between the first electromotive force V ₁ and the second photovoltaic force V ₂ with the threshold voltage V _th. The display unit 130 is compared. 9A and 9B are graphs for explaining the second contact detection operation. As shown in FIG. 9A, the difference value V _diff is _calculated based on the first photovoltaic power based on a digital signal obtained by A / D converting the received light signal (analog signal) by the A / D conversion circuit 165. It is calculated by measuring V ₁ and the second photovoltaic power V ₂ and subtracting these measured values. Then, based on the calculated difference value V _diff and the threshold voltage V _th stored in the contact detection unit 120 in advance, the contact between the display unit 130 and the object 10 is detected.

For example, if the difference value V _diff is smaller than the threshold voltage V _th (V _diff <V _th ), it can be determined that the display unit 130 and the object 10 are not in contact. Further, if the difference value V _diff is equal to or greater than the threshold voltage V _th (V _diff ≧ V _th ), it can be determined that the display unit 130 and the object 10 are in contact with each other.

In the second contact detection operation, the threshold voltage _Vth can be set to an arbitrary value. Therefore, unlike the first contact detection operation, regardless of the characteristics of the elements included in the contact detection unit 120, the display unit Contact between the object 130 and the object 10 can be detected. Therefore, in the second contact detection operation, the contact between the display unit 130 and the target object 10 can be detected with higher accuracy compared to the first contact detection operation.

In the second contact detection operation, for example, it is possible to remove the influence of fluctuations in the photovoltaic force due to external light (for example, a fluorescent lamp). As shown in FIG. 9B, compared with the dark place, in the bright place, the photovoltaic power is increased by V _noise due to the external light. However, since both the first electromotive force V ₁ ′ (= V ₁ + V _noise ) and the second electromotive force V ₂ ′ (= V ₂ + V _noise ) are increased by the same amount, the difference value is obtained in the dark place and in the bright place. V _diff is constant. Therefore, in the second contact detection operation, malfunction due to external light can be prevented.

Further, in the second contact detection operation, it is possible to remove the influence of the fluctuation of the photovoltaic power caused by the temperature change of the external environment. In general, it is known that the emission intensity of the LED 131 decreases due to heat generated due to long-time lighting. For this reason, the photovoltaic power is reduced by V _{noise corresponding to} the decrease in emission intensity due to the temperature rise of the LED 131. However, both the first electromotive force V ₁ ′ (= V ₁ −V _noise ) and the second electromotive force V ₂ ′ (= V ₂ −V _noise ) are the same as in the case of the fluctuation of the photovoltaic force due to the external light. Therefore, the difference value V _diff is constant regardless of the temperature of the LED 131. Therefore, in the second contact detection operation, malfunction due to the temperature rise of the LED 131 can also be prevented.

Further, in the second contact detection operation, the influence of the variation in the photovoltaic power due to the individual difference of the LEDs 131 can be removed. In general, since there are individual differences in the LEDs 131, the absolute value of the photovoltaic power varies depending on the LED 131 used. However, even if there is an individual difference in the LED 131, the difference value V _diff is constant regardless of the LED 131 used. Therefore, in the second contact detection operation, malfunction due to individual differences of the LEDs 131 can also be prevented.

In the third contact detection operation, similarly to the second contact detection operation, the first photovoltaic power V ₁ and the second photovoltaic power V are based on a digital signal obtained by performing A / D conversion. ₂ is measured. Next, based on the measured first photovoltaic power V ₁ and second photovoltaic power V ₂ and the threshold voltage V _th stored in the contact detection unit 120 in advance, the contact between the display unit 130 and the object 10. Is detected.

For example, if the photovoltaic voltage V generated in the first light emitting unit 132R is smaller than the threshold voltage _Vth (V < _Vth ), it can be determined that the display unit 130 and the object 10 are not in contact. Further, if the photovoltaic voltage V generated in the first light emitting unit 132R is equal to or larger than the threshold voltage _Vth (V ≧ _Vth ), it is determined that the display unit 130 and the object 10 are in contact with each other. be able to.

In the third contact detection operation, the threshold voltage _{Vth is set} to an arbitrary value without being determined by the characteristics of the elements included in the contact detection unit 120 (more specifically, the light reception detection unit 160 that generates a light reception signal). Can be set to For example, by setting the threshold voltage _{V th} of about 1.3V when the first electromotive force _{V 1} is a 1.2V, the contact detection unit 120 has a display unit 130 and the object 10 is actually in contact Even if it is not, there is no risk of mistakenly judging that it is always in contact.

On the other hand, in the third contact detection operation, since the difference value V _diff is not calculated as compared with the second contact detection operation, the influence caused by the external environment (external light, temperature change) and individual differences of the LEDs 131 is affected. I will receive it. However, by setting the threshold voltage (V _th ± V _noise ) in consideration of the photovoltaic voltage fluctuation V _noise due to the external environment, it is possible to prevent malfunction caused by the external environment even in the third contact detection operation. Can do. Further, by setting the threshold voltage V _th according to the individual difference of the LEDs 131, it is possible to prevent malfunction due to the individual difference of the LEDs 131 even in the third contact detection operation.

(effect)
As described above, in display device 100 according to the present embodiment, light emitted from second light emitting unit 132G is detected by first light emitting unit 132R. For this reason, in display device 100 according to the present embodiment, contact between display unit 130 and target object 10 can be detected without depending on external light.

  Further, when detecting the contact of the object 10, the control unit 110 controls the light emission of the LED 131 while turning on or off the light emitting unit 132 so that it cannot be recognized by human vision. Accordingly, the LED 131 can be caused to emit light so that light emitted from the light emitting unit 132 can be visually recognized even in a state of functioning as an optical sensor. Thereby, in display device 100 according to the present embodiment, it is possible to display an image on display unit 130 while detecting contact between display unit 130 and object 10 without limiting the emission color.

  In the above embodiment, the LED of the display device 100 has been described as having the three light emitting units 132 (the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B). The display device is not limited to this mode. FIG. 10 is a block diagram illustrating a configuration of a display device 100 ′ according to a modification. For example, in the display device according to the present invention, it is sufficient that the LED has a plurality of light emitting units. As shown in FIG. 10, the LED 131 ′ of the display unit 130 ′ in the light emitting device 100 ′ is the first light emitting unit. You may have two light emission part 132 'of 132R and the 2nd light emission part 132G.

  In this case, the control unit 110 causes the LED 131 'to emit light with four light emission patterns. 11A to 11D show timing charts of the light emitting unit 132 in the light emission patterns 1 ′ to 4 ′. When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R is visually recognized and the light emission of the second light emitting unit 132G is not visually recognized, the second light emitting unit 132G is pulse-lit as shown in FIG. 11A. During this time, the first light emitting unit 132R is extinguished by pulses (light emission pattern 1 ′). When the LED 131 is caused to emit light so that the light emission of the second light emitting unit 132G is visible and the light emission of the first light emitting unit 132R is not visually recognized, as shown in FIG. 11B, the second light emitting unit 132G is turned on, The first light emitting unit 132R is turned off (light emission pattern 2 ′). When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R and the second light emitting unit 132G can be visually recognized, as shown in FIG. 11C, the second light emitting unit 132G is turned on and the first light emitting unit 132R is turned on. Is turned off (light emission pattern 3 '). When the LED 131 is caused to emit light so that the light emission of the first light emitting unit 132R and the second light emitting unit 132G is not visually recognized, as shown in FIG. 11D, the first light emitting unit 132R is turned off and the second light emitting unit 132G is turned off. The pulse is lit (light emission pattern 4 ').

Moreover, although the display apparatus 100 demonstrated the aspect which detects the contact with the display part 130 and the target object 10 in the said embodiment, the display apparatus which concerns on this invention is not limited to this aspect. FIG. 12 is a schematic diagram for explaining an aspect for detecting the approach between the display unit 130 and the object 10. In the display device according to the present invention, as shown in FIG. 12, the approach between the display unit 130 and the object 10 may be detected. In this case, the approach can be detected instead of the contact by adjusting the magnitude of the threshold voltage _Vth for determining whether or not the display unit 130 and the object 10 are approaching. In this case, compared with the case where contact is detected, the first electromotive force V ₁ ″ in the non-contact state has the same value as the first electromotive force V ₁ in the non-contact state (V ₁ ″ = V ₁ ). However, since the distance between the display unit 130 and the object 10 is increased, the amount of light emitted from the second light emitting unit 132G and reflected by the object 10 is incident on the first light emitting unit 132R decreases. The second electromotive force V ₂ ″ in the approaching state is smaller than the second electromotive force V ₂ in the contacting state (V ₂ ″ <V ₂ ). Accordingly, the difference value V _diff ″ between the first electromotive force V ₁ ″ and the second electromotive force V ₂ ″ is also reduced (V _diff ″ <V _diff ). Therefore, by reducing the magnitude of the threshold voltage V _{th to be} compared, the display device according to the present invention can also detect the approach between the display unit 130 and the object 10. At this time, by adjusting the magnitude of the threshold voltage _Vth , the distance between the display unit 130 and the object 10 at the time of approach detection can also be adjusted.

  In the display device 100 according to the above-described embodiment, the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B are controlled by signals having the same peak voltage value. It is not limited to this aspect. For example, the emission color of the LED 131 may be controlled by adjusting the magnitude of power (peak voltage value) for driving the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B. Thereby, in the display device 100 according to the above-described embodiment, full color can be realized by adjusting the light intensity from each light emitting unit.

  Moreover, in the said embodiment, although the display apparatus 100 was light-emitted by the light emission patterns 1-8, the light emission pattern of the display apparatus which concerns on this invention is not limited to this. FIG. 13 is a timing chart of the light emitting unit showing an example of another light emission pattern of the display device 100. For example, as shown in FIG. 13, the control unit 110 controls the light emission of the LED 131 by adjusting the pulse widths of the first light emitting unit 132R, the second light emitting unit 132G, and the third light emitting unit 132B (pulse width modulation: (PWM control). Such control is preferable from the viewpoint of realizing full color by detecting the contact between the display unit 130 and the object 10 and adjusting the light intensity from each light emitting unit.

  Further, in the display device 100 according to the above embodiment, when the LED 131 is caused to emit light so that the light emission of the light emitting unit 132 can be visually recognized, the control unit 110 causes the light emitting unit 132 to be continuously turned on or the pulse is turned off. The light emitting unit 132 was continuously turned on except when the pulse was turned off. However, the display device according to the present invention is not limited to this mode. For example, the control unit 110 may control the LED 131 so that the light emission of the light emitting unit 132 is visually recognized by a dynamic lighting method. For example, when the lighting time of the LED 131 is 1 microsecond, the peak luminance is 1000 millicandelas, and the pulse period is 1 millisecond, the average luminance is 1 millicandelas. Further, when the LED 131 is turned on for 1 microsecond, the peak luminance is 5000 millicandelas, and the pulse period is 5 milliseconds, the average luminance is 1 millicandelas. Here, consider a case where the light emission of the LED 131 is controlled by the PWM control described above. As shown in FIG. 13, assuming that the turn-off time of the LED 131 is 5 milliseconds and the turn-on time is 1 millisecond, the total pulse period is 6 milliseconds. In the case of an 8 × 8 display, there is no problem if the switching time per line is 2 milliseconds, but flickering occurs when the switching time per line is about 3 milliseconds. That is, it can be said that it takes about 24 milliseconds (= 3 milliseconds × 8) to switch over the entire display. From this point of view, when the pulse period is 6 milliseconds, the LED 131 can be controlled by dynamic lighting for the third to fourth rows.

  In addition, in the display device 100 according to the above-described embodiment, the mode in which the LED 131 is used as the light emitting semiconductor element has been described, but the display device according to the present invention is not limited to this mode. For example, an EL element may be used as the light emitting semiconductor element.

Furthermore, in the display device 100 according to the above embodiment, in the light emission patterns 3 and 5 to 7, the control unit 110 allows the first light emitting unit 132 </ b> R to receive the light from the second light emitting unit 132 </ b> G. While the light emission of 132R and the second light emitting unit 132G was controlled, the third light emitting unit 132B was turned off. However, the display device 100 according to the present invention is not limited to this mode. When the first light emitting unit 132R of the LED 131 has high sensitivity to the light emitted from the third light emitting unit 132B by controlling the light emission of the third light emitting unit 132B as in the above embodiment, the first electromotive force V ₁ in the non-contact state causes increased by the light emitted from the third light emitting portion 132B, as a result, can prevent that the difference value V _diff becomes small. That is, controlling the light emission of the third light emitting unit 132B as in the above embodiment is preferable from the viewpoint of preventing malfunction caused by a decrease in sensitivity to contact detection between the display unit 130 and the object 10. However, when the sensitivity of the first light emitting unit 132R to the light emitted from the third light emitting unit 132B is not so high as to cause the malfunction as described above (for example, see the LED 131 used in the above embodiment, FIG. 3A). The control unit 110 controls the light emission of the first light emitting unit 132R and the second light emitting unit 132G so that the first light emitting unit 132R can receive the light from the second light emitting unit 132G. The light emitting unit 132B may be turned on (continuously) instead of being turned off.

  The display device of the present invention can detect contact or approach of an object. For example, the display device of the present invention is useful as a touch panel display, illumination, or object detection device.

DESCRIPTION OF SYMBOLS 10 Target object 20 External signal 100, 100 'Display apparatus 110 Control part 120 Contact detection part (detection part)
130, 130 'display part 131, 131' light emitting diode (LED)
132, 132 ′ Light emitting unit 132R First light emitting unit 132G Second light emitting unit 132B Third light emitting unit 133 Common terminal 134r First terminal 134g Second terminal 134b Third terminal 140 Display control unit 150 Lighting control unit 160 Light reception detection unit 165 A / D conversion circuit

Claims (9)

A display device capable of detecting contact or approach of an object,
A display unit in which a plurality of light emitting semiconductor elements each having a first light emitting unit and a second light emitting unit having a light emission wavelength shorter than that of the first light emitting unit are arranged;
A control unit for controlling light emission of the light emitting semiconductor element;
Light that is emitted from the second light emitting unit and is reflected by the object and incident on the first light emitting unit when the object is in contact with or close to the display unit. Based on an electromotive force, a detection unit for detecting contact or approach between the display unit and the object;
Have
The controller is
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit is visually recognized and the light emission of the second light emitting unit is not visually recognized, the second light emitting unit is pulse-lit while the second light emitting unit is being lit. 1 Turn off the pulse of the light emitting part,
When the light emitting semiconductor element is caused to emit light so that light emitted from the second light emitting unit is visually recognized and light emitted from the first light emitting unit is not visually recognized, the second light emitting unit is turned on and the first light emitting unit is illuminated. Is turned off,
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit and the second light emitting unit can be visually recognized, the second light emitting unit is turned on and the first light emitting unit is turned off in pulses.
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit and the second light emitting unit is not visually recognized, the first light emitting unit is turned off and the second light emitting unit is turned on in pulses.
Display device.   The detection unit includes a first photovoltaic power generated in the first light emitting unit by light incident on the first light emitting unit in a state where the object is not in contact with or approaching the display unit, and the target is Based on the difference value of the second photovoltaic power generated in the first light emitting unit due to the light incident on the first light emitting unit in contact with or close to the display unit, and the threshold voltage stored in the detection unit in advance The display device according to claim 1, wherein contact or approach between the display unit and the object is detected.   The detection unit is configured to output the first light based on a digital signal obtained by performing A / D conversion on an analog signal indicating the magnitude of the photovoltaic power corresponding to the intensity of light incident on the first light emitting unit. The display device according to claim 2, wherein an electromotive force and the second photovoltaic force are measured.   4. The display device according to claim 1, wherein when the first light emitting unit is turned off, the control unit turns off the first light emitting unit with a pulse width of 1 microsecond or less. 5. .   5. The display device according to claim 1, wherein when the second light emitting unit is pulse-lit, the control unit is configured to pulse the second light emitting unit with a pulse width of 1 microsecond or less. . The light emitting semiconductor element further includes a third light emitting unit having an emission wavelength shorter than that of the second light emitting unit,
The controller is
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit is visually recognized and the light emission of the second light emitting unit and the third light emitting unit is not visually recognized, the third light emitting unit is turned off. , While the second light emitting unit is turned on in pulses, the first light emitting unit is turned off in pulses,
When the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting unit is visually recognized and the light emission of the first light emitting unit and the third light emitting unit is not visually recognized, the second light emitting unit is turned on. , Turn off the first light emitting unit and the third light emitting unit,
When the light emitting semiconductor element is caused to emit light so that light emission of the third light emitting unit is visually recognized and light emission of the first light emitting unit and the second light emitting unit is not visually recognized, the first light emitting unit is turned off, And while turning on the third light-emitting unit, the second light-emitting unit is pulse-lit,
When the light emitting semiconductor element is caused to emit light so that light emission of the first light emitting unit and the second light emitting unit is visually recognized and light emission of the third light emitting unit is not visually recognized, the second light emitting unit is turned on, And turning off the third light-emitting unit, and turning off the first light-emitting unit in pulses,
In the case where the light emitting semiconductor element is caused to emit light so that light emission of the second light emitting unit and the third light emitting unit is visually recognized and light emission of the first light emitting unit is not visually recognized, the second light emitting unit and the third light emitting unit. Turning on the light emitting unit and turning off the first light emitting unit;
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit and the third light emitting unit is visually recognized and the light emission of the second light emitting unit is not visually recognized, the third light emitting unit is turned on. , While the second light emitting unit is turned on in pulses, the first light emitting unit is turned off in pulses,
When the light emitting semiconductor element is caused to emit light so that light emitted from the first light emitting unit, the second light emitting unit, and the third light emitting unit is visually recognized, the second light emitting unit and the third light emitting unit are turned on. In addition, the first light emitting unit is turned off in pulses,
When the light emitting semiconductor element is caused to emit light so that light emission of the first light emitting unit, the second light emitting unit, and the third light emitting unit is not visually recognized, the first light emitting unit and the third light emitting unit are turned off. , Pulse lighting the second light emitting unit,
The display apparatus as described in any one of Claims 1-5. The light emitting semiconductor element further includes a third light emitting unit having an emission wavelength shorter than that of the second light emitting unit,
The controller is
When the light emitting semiconductor element is caused to emit light so that the light emission of the first light emitting unit is visually recognized and the light emission of the second light emitting unit and the third light emitting unit is not visually recognized, the third light emitting unit is turned off. , While the second light emitting unit is turned on in pulses, the first light emitting unit is turned off in pulses,
When the light emitting semiconductor element is caused to emit light so that the light emission of the second light emitting unit is visually recognized and the light emission of the first light emitting unit and the third light emitting unit is not visually recognized, the second light emitting unit is turned on. , Turn off the first light emitting unit and the third light emitting unit,
When the light emitting semiconductor element is caused to emit light so that the light emission of the third light emitting unit is visually recognized and the light emission of the first light emitting unit and the second light emitting unit is not visually recognized, the first light emitting unit is turned off. , While the second light emitting unit is lit in pulses, the third light emitting unit is turned off in pulses,
When the light emitting semiconductor element is caused to emit light so that light emission of the first light emitting unit and the second light emitting unit is visually recognized and light emission of the third light emitting unit is not visually recognized, the second light emitting unit is turned on, And turning off the third light-emitting unit, and turning off the first light-emitting unit in pulses,
When the light emitting semiconductor element is caused to emit light so that light emission of the second light emitting unit and the third light emitting unit is visually recognized and light emission of the first light emitting unit is not visually recognized, the second light emitting unit is turned on, And turning off the first light-emitting unit and turning off the third light-emitting unit,
When the light emitting semiconductor element is caused to emit light so that light emitted from the first light emitting unit and the third light emitting unit is visually recognized and light emitted from the second light emitting unit is not visually recognized, the second light emitting unit is pulse-lit. The first light-emitting unit and the third light-emitting unit are turned off during the operation,
When the light emitting semiconductor element is caused to emit light so that light emitted from the first light emitting unit, the second light emitting unit, and the third light emitting unit is visually recognized, the second light emitting unit is turned on and the first light emitting unit is turned on. Part and the third light emitting unit are extinguished in pulses,
When the light emitting semiconductor element is caused to emit light so that light emission of the first light emitting unit, the second light emitting unit, and the third light emitting unit is not visually recognized, the first light emitting unit and the third light emitting unit are turned off. , Pulse lighting the second light emitting unit,
The display apparatus as described in any one of Claims 1-5. The emission color of the first light emitting unit is red,
The emission color of the second light emitting unit is green.
The display apparatus as described in any one of Claims 1-5. The emission color of the first light emitting unit is red,
The emission color of the second light emitting unit is green,
The emission color of the third light emitting unit is blue.
The display device according to claim 6 or 7.

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