Abstract: A downsized electronic device with an eye tracking function is provided. The electronic device with an eye tracking function includes a display device, an infrared light source, and an optical system. The display device includes a display element and a light-receiving element; the infrared light source has a function of emitting infrared light; the light-receiving element has a function of detecting the infrared light reflected by an eyeball; and the optical system includes a first optical element positioned on an optical path through which an image from the display element enters the eyeball and a second optical element positioned on an optical path through which the reflected infrared light enters the light-receiving element. The light-receiving element is integrated with the display device and thus, the electronic device can have a reduced size.

Abstract: A semiconductor device with high productivity is provided. The semiconductor device includes a first and a second transistor and a first and a second capacitor. The first and the second transistor include gate electrodes and back gate electrodes. The second transistor is provided in a layer above the first transistor, and the second capacitor is provided in a layer above the first capacitor. One electrode of the first capacitor is electrically connected to one of a source electrode and a drain electrode of the first transistor and electrically connected to one of a source electrode and a drain electrode of the second transistor. The other electrode of the first capacitor is formed in the same layer as the back gate electrode of the second transistor.

Abstract: A novel memory device is provided. A first cell array including a plurality of memory cells and a second cell array including a plurality of memory cells are stacked. One of two bit lines of a first bit line pair is electrically connected to A memory cells of the first cell array, and the other of the two bit lines of the first bit line pair is electrically connected to D memory cells of the second cell array. One of two bit lines of a second bit line pair is electrically connected to B memory cells of the first cell array and F memory cells of the second cell array, and the other of the two bit lines of the second bit line pair is electrically connected to C memory cells of the first cell array and E memory cells of the second cell array. The first bit line pairs and the second bit line pairs are alternately provided.

Abstract: To provide a display device that is suitable for increasing in size, a display device in which display unevenness is suppressed, or a display device that can display an image along a curved surface. The display device includes a first display panel and a second display panel each including a pair of substrates. The first display panel and the second display panel each include a first region which can transmit visible light, a second region which can block visible light, and a third region which can perform display. The third region of the first display panel and the first region of the second display panel overlap each other. The third region of the first display panel and the second region of the second display panel do not overlap each other.

Abstract: Provided is a display system or a display device that is suitable for increasing in size. The display system includes a first display panel, a second display panel, a detection means, and a compensation means. The first display panel includes a first display region. The second display panel includes a second display region. The first display region and the second display region include a first region where they overlap. The detection means has a function of detecting the size of the first region. The compensation means has a function of compensating an image displayed on the first display region in accordance with the change in the size of the first region.

Abstract: To provide a light-emitting device whose amount of light can be adjusted, or the like. The amount of light emitted from the light-emitting device can be adjusted by controlling the magnitude of the constant current pulse by a control signal. Specifically, the light-emitting device includes a constant current supply configured to be supplied with a control signal and a control pulse signal and configured to supply a constant current pulse; a control device configured to supply the control signal; a driver circuit configured to supply the control pulse signal; and a light-emitting panel configured to be supplied with the constant current pulse. The control signal is a signal for controlling the magnitude of the constant current pulse. The light-emitting panel includes a light-emitting element. The current density of the light-emitting element is greater than or equal to 10 mA/cm2 and less than or equal to 1000 mA/cm2.

Abstract: There has been a problem that difference in refractive index between an opposite substrate or a moisture barrier layer provided thereover, and air is maintained large, and light extraction efficiency is low. Further, there has been a problem that peeling or cracking due to the moisture barrier layer is easily generated, which leads to deteriorate the reliability and lifetime of a light-emitting element. A light-emitting element comprises a pixel electrode, an electroluminescent layer, a transparent electrode, a passivation film, a stress relieving layer, and a low refractive index layer, all of which are stacked sequentially. The stress relieving layer serves to prevent peeling of the passivation film. The low refractive index layer serves to reduce reflectivity of light generated in the electroluminescent layer in emitting to air. Therefore, a light-emitting element with high reliability and long lifetime and a display device using the light-emitting element can be provided.

Abstract: A novel display panel that is highly convenient, useful, or reliable is provided. The display panel includes a display region and includes a first pixel, a second pixel, a third pixel, and a filter. The first pixel emits light with a spectrum having a local maximum at a first wavelength, the second pixel emits light with a spectrum having a local maximum at a second wavelength, and the third pixel emits light with a spectrum having a local maximum at a third wavelength. The filter includes a region overlapping with the first pixel, a region overlapping with the second pixel, and a region overlapping with the third pixel, and the filter has a transmittance spectrum having local minimums at a fourth wavelength and a fifth wavelength. The second wavelength is longer than the first wavelength. The third wavelength is longer than the second wavelength. The fourth wavelength is between the first wavelength and the second wavelength. The fifth wavelength is between the second wavelength and the third wavelength.

Abstract: To provide a display device that is suitable for increasing in size, a display device in which display unevenness is suppressed, or a display device that can display an image along a curved surface. The display device includes a first display panel and a second display panel each including a pair of substrates. The first display panel and the second display panel each include a first region which can transmit visible light, a second region which can block visible light, and a third region which can perform display. The third region of the first display panel and the first region of the second display panel overlap each other. The third region of the first display panel and the second region of the second display panel do not overlap each other.

Abstract: There has been a problem that difference in refractive index between an opposite substrate or a moisture barrier layer provided thereover, and air is maintained large, and light extraction efficiency is low. Further, there has been a problem that peeling or cracking due to the moisture barrier layer is easily generated, which leads to deteriorate the reliability and lifetime of a light-emitting element. A light-emitting element comprises a pixel electrode, an electroluminescent layer, a transparent electrode, a passivation film, a stress relieving layer, and a low refractive index layer, all of which are stacked sequentially. The stress relieving layer serves to prevent peeling of the passivation film. The low refractive index layer serves to reduce reflectivity of light generated in the electroluminescent layer in emitting to air. Therefore, a light-emitting element with high reliability and long lifetime and a display device using the light-emitting element can be provided.

Abstract: A display panel is provided. In addition, a display device is provided. Furthermore, an input/output device is provided. Furthermore, a data processing device is provided.

Abstract: A display device which exhibits light with high color purity is provided. A display device with low power consumption is provided. An embodiment is a display device which includes a first pixel electrode, a second pixel electrode, a light-emitting layer, a common electrode, a first protective layer, and a semi-transmissive layer. The light-emitting layer includes a first region positioned over the first pixel electrode and a second region positioned over the second pixel electrode. The common electrode is positioned over the light-emitting layer. The first protective layer is positioned over the common electrode. The semi-transmissive layer is positioned over the first protective layer. Reflectivity with respect to visible light of the semi-transmissive layer is higher than reflectivity with respect to visible light of the common electrode. The semi-transmissive layer does not overlap with the first region and overlaps with the second region.

Abstract: To provide a novel display panel that is highly convenient or reliable. To provide a novel input and output device that is highly convenient or reliable. To provide a novel data processing device that is highly convenient or reliable. To provide a method for manufacturing a novel display panel that is highly convenient or reliable. The display panel includes a pixel, a third conductive film electrically connected to the pixel, an insulating film including an opening portion overlapping with the third conductive film, and an electrode including a first region in contact with the third conductive film and a second region functioning as a contact point.

Abstract: A high-resolution display device is provided. The display device includes a plurality of light-emitting units emitting light of different colors. The light-emitting unit has a microcavity structure and intensifies light with a specific wavelength. In the light-emitting units emitting light of different colors, reflective layers with different thicknesses are formed, an insulating layer is formed to cover the reflective layers, and then a top surface of the insulating layer is subjected to planarization treatment, whereby an insulating layer with different thicknesses is formed. After that, light-emitting elements emitting white light are formed over the planarized top surface of the insulating layer to overlap with the respective reflective layers, whereby the light-emitting units that intensify different colors due to different optical path lengths are separately formed.

Abstract: Provided is a display system or a display device that is suitable for increasing in size. The display system includes a first display panel, a second display panel, a detection means, and a compensation means. The first display panel includes a first display region. The second display panel includes a second display region. The first display region and the second display region include a first region where they overlap. The detection means has a function of detecting the size of the first region. The compensation means has a function of compensating an image displayed on the first display region in accordance with the change in the size of the first region.

Abstract: A display device that can display an image along a curved surface is provided. In the display device, a first display panel and a second display panel overlap each other with a light-transmitting layer provided therebetween. The light-transmitting layer is positioned on a display surface side of the first display panel, and on a side opposite to the display surface of the second display panel. The light-transmitting layer has an average transmittance of 80% or more with respect to light in the wavelength range of 450 nm to 700 nm and a refractive index higher than that of air. A display region of the first display panel overlaps a region transmitting visible light of the second display panel with the light-transmitting layer provided therebetween. It is preferred that the display region of the first display panel not overlap with a region blocking visible light of the second display panel.

Abstract: A novel memory device is provided. A first cell array including a plurality of memory cells and a second cell array including a plurality of memory cells are stacked. One of two bit lines of a first bit line pair is electrically connected to A memory cells of the first cell array, and the other of the two bit lines of the first bit line pair is electrically connected to D memory cells of the second cell array. One of two bit lines of a second bit line pair is electrically connected to B memory cells of the first cell array and F memory cells of the second cell array, and the other of the two bit lines of the second bit line pair is electrically connected to C memory cells of the first cell array and E memory cells of the second cell array. The first bit line pairs and the second bit line pairs are alternately provided.

Abstract: There has been a problem that difference in refractive index between an opposite substrate or a moisture barrier layer provided thereover, and air is maintained large, and light extraction efficiency is low. Further, there has been a problem that peeling or cracking due to the moisture barrier layer is easily generated, which leads to deteriorate the reliability and lifetime of a light-emitting element. A light-emitting element includes a pixel electrode, an electroluminescent layer, a transparent electrode, a passivation film, a stress relieving layer, and a low refractive index layer, all of which are stacked sequentially. The stress relieving layer serves to prevent peeling of the passivation film. The low refractive index layer serves to reduce reflectivity of light generated in the electroluminescent layer in emitting to air. Therefore, a light-emitting element with high reliability and long lifetime and a display device using the light-emitting element can be provided.

Abstract: A display device that can display an image along a curved surface is provided. In the display device, a first display panel and a second display panel overlap each other with a light-transmitting layer provided therebetween. The light-transmitting layer is positioned on a display surface side of the first display panel, and on a side opposite to the display surface of the second display panel. The light-transmitting layer has an average transmittance of 80% or more with respect to light in the wavelength range of 450 nm to 700 nm and a refractive index higher than that of air. A display region of the first display panel overlaps a region transmitting visible light of the second display panel with the light-transmitting layer provided therebetween. It is preferred that the display region of the first display panel not overlap with a region blocking visible light of the second display panel.

Abstract: A small light-emitting device is provided. A light-emitting device which is less likely to produce a shadow is provided. A structure including a switching circuit for supplying a pulsed constant current and a light-emitting panel supplied with the pulsed constant current has been conceived.