Display device

A display device includes a display panel and at least one light modulation panel. The display panel includes a substrate and a plurality of micro light emitting semiconductors disposed on the substrate. The light modulation panel is disposed on a light emitting surface of the display panel and includes a light modulation unit. The light modulation panel is configured to change a transmittance of the light modulation unit according to a light modulation control signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 106131482 filed in Taiwan R.O.C on Sep. 13, 2017, the entire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to a display device, more particularly to a display device including a light modulator and display panel.

BACKGROUND

With the development of smart devices, many display devices, such as portable electronic devices and automotive equipment, are being used in our daily lives. In order to allow a display device to provide clear and non-glare images under different conditions, a conventional display device adjusts image brightness by adjusting an intensity of light emitted by a light source, and the light intensity of the light source is adjusted according to an intensity of ambient light. In a display device using light emitting diodes (LEDs) as the light source, the intensity of light is adjusted by a drive current in the LEDs.

SUMMARY

According to one aspect of the disclosure, a display device includes a display panel and at least one light modulation panel. The display panel includes a substrate and a plurality of micro light emitting semiconductors disposed on the substrate. The light modulation panel is disposed on a light emitting surface of the display panel and includes a light modulation unit. The light modulation panel is configured to change a transmittance of the light modulation unit according to a light modulation control signal.

According to another aspect of the disclosure, a display device includes a display panel and at least one light modulation panel. The display panel includes a substrate and a plurality of micro light emitting semiconductors disposed on the substrate. The light modulation panel is disposed on a light emitting surface of the display panel and includes a light modulation unit, and a transmittance of the light modulation unit has a positive correlation to an intensity of ambient light.

DETAILED DESCRIPTION

Please refer toFIG. 1showing a cross-sectional view of a display device according to a first embodiment of the disclosure. In this embodiment, a display device1includes a display panel100, a light modulation panel200, an optical sensor300and a controller400.

The display panel100includes a substrate110, a plurality of micro light emitting semiconductors120and a protection layer130. The substrate110, for example, is a complementary metal-oxide semiconductor (CMOS) substrate, a liquid crystal on silicon (LCOS) substrate, a thin film transistor (TFT) substrate or other substrates containing driver circuit. The micro light emitting semiconductors120is disposed on substrate110in a matrix manner, and the micro light emitting semiconductors120are electrically connected to the driver circuit on the substrate110. The micro light emitting semiconductor120, for example, is a micro LED. The protection layer130is disposed on the substrate110, and the micro light emitting semiconductors120are located between the protection layer130and the substrate110. The protection layer130is configured to protect the micro light emitting semiconductors120so as to prevent influences on the micro light emitting semiconductors120due to external air or water. The protection layer130, for example, is made of epoxy, silicon oxide or transparent polymer.

The light modulation panel200is disposed on a light emitting surface of the display panel100. The light modulation panel200includes a support210, a light modulation unit220, a first electrode230, a second electrode240and a protection layer250. The first electrode230is disposed between the support210and the second electrode240. The support210, for example, is a transparent glass plate or a transparent polymer plate. Both the first electrode230and the second electrode240, for example, are made of a transparent conductor such as indium tin oxide (ITO) and indium zinc oxide (IZO).

The light modulation unit220is disposed between the first electrode230and the second electrode240. The light modulation unit220includes electrochromic material such as viologen, titanium dioxide, polyoxotungstate, tungsten trioxide or polyaniline. When the voltage applied to the light modulation unit220by the first electrode230and the second electrode240is changed, the transmittance of the light modulation unit220is also changed. For example, when the first electrode230and the second electrode240apply a voltage of 5V to the light modulation unit220, the transmittance of the light modulation unit220reduces. The reduction of the transmittance is dependent on the material, and it is worth noting that the present disclosure is not limited to the aforementioned example.

The protection layer250is disposed on the support210. The light modulation unit220, the first electrode230and the second electrode240are located between the protection layer250and the support210. The protection layer250is configured to protect the light modulation unit220, the first electrode230and the second electrode240so as to prevent influences on the light modulation unit220, the first electrode230and the second electrode240due to external air or water. The protection layer250, for example, is made of epoxy, silicon oxide or transparent polymer.

In this embodiment, the light modulation panel200is disposed on the light emitting surface of the display panel100, and a surface of the protection layer250away from the support210faces toward a light emitting surface of the protection layer130, but the present disclosure is not limited thereto. In some other embodiments, the light modulation panel is disposed on the light emitting surface of the display panel, and a surface of the support away from the light modulation unit faces toward the light emitting surface of the protection layer.

The optical sensor300is disposed on the support210of the light modulation panel200. The optical sensor300is configured to sense an intensity of ambient light in an environment where the display device1is located. A sensing area (not shown in the drawing) of the optical sensor300, for example, is opposite to the display panel100or faces toward an external environment where the display device1is located. In this embodiment, the optical sensor300is a micro-scale optical sensor with sophisticated light sensing capability. Specifically, the optical sensor300, for example, is a CMOS, a charge-coupled device (CCD), a photodiode or a photosensitive element. The optical sensor300is disposed near the periphery of the support210such that the display screen is prevented from blocked by the optical sensor300. It is worth noting that the present disclosure is not limited to the position of the optical sensor. In some other embodiments, the optical sensor is located in another position where it is able to receive ambient light.

The controller400is disposed on the support210of the light modulation panel200. The controller400is electrically connected to the light modulation unit220and the optical sensor300via a circuit structure (not shown in the drawing). The circuit structure may be a transparent conductive pattern which does not block the display screen. The controller400receives the intensity of ambient light from the optical sensor300and generates a light modulation control signal by comparing the intensity of ambient light with a predetermined intensity of ambient light. The predetermined intensity of ambient light, for example, is a light intensity which is comfortable for the human eye to achieve visual comfort. The value of the predetermined intensity of ambient light is stored in a memory medium of the controller400or an external memory medium (not shown in the drawings) electrically connected to the controller400. The light modulation control signal is transmitted from the controller400through the circuit structure into the light modulation unit220in order to adjust the transmittance of the light modulation unit220, and there is a logarithmic relationship between the transmittance of the light modulation unit220and a sensitivity of the human eye to light. In detail, when the intensity of ambient light is greater than the predetermined intensity of ambient light, the controller400generates the light modulation control signal to enhance the transmittance of the light modulation unit220. When the intensity of ambient light is less than the predetermined intensity of ambient light, the controller400generates the light modulation control signal to reduce the transmittance of the light modulation unit220. In this embodiment, the controller400is a micro-scale controller provided to control the transmittance precisely. Specifically, the controller400, for example, is a digital signal processor (DSP), a central processing unit (CPU) or a micro control unit (MCU), but the present disclosure is not limited thereto.

In this embodiment, the light modulation panel200changes the transmittance of the light modulation unit220according to the light modulation control signal generated by the controller400. Thus, when the display device1is located in an environment with high intensity of ambient light (high light condition), the light modulation unit220is driven to a high transmittance state by the light modulation control signal, such that most of the amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200, thereby providing clear images. When the display device1is located in an environment with low intensity of ambient light (low light condition), the light modulation unit220is driven to a low transmittance state by the light modulation control signal, such that only a small amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200, thereby preventing uncomfortable visual effect due to overly bright images.

Moreover, the light modulation panel200of the display device1is used to adjust image brightness, such that the image brightness is changed according to the transmittance of the light modulation panel200. The intensity of device light emitted by the micro light emitting semiconductor120only slightly changed by a drive current. Therefore, the adjustment of image brightness is less dependent on the drive current in the micro light emitting semiconductor120, such that an unreliable adjustment of image brightness due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor120is prevented.

In this embodiment, the optical sensor300is configured to sense the intensity of ambient light in the environment where the display device1is located, but the present disclosure is not limited thereto. In some other embodiments, the optical sensor is configured to sense the intensity of device light emitted by the micro light emitting semiconductors, and the sensing area of the optical sensor faces toward the display panel. A value of a predetermined intensity of device light is stored in the controller. The controller receives the intensity of device light from the optical sensor and generates the light modulation control signal by comparing the intensity of device light with the predetermined intensity of device light. The light modulation panel changes the transmittance of the light modulation unit according to the light modulation control signal. In detail, when the intensity of device light is greater than the predetermined intensity of device light, the controller generates the light modulation control signal to reduce the transmittance of the light modulation unit. Therefore, when an image with high brightness is displayed, the light modulation unit of the light modulation panel prevents the light intensity of the micro light emitting semiconductor from being overly high, thereby alleviating human eye irritation.

FIG. 2is a cross-sectional view of a display device according to a second embodiment of the disclosure. Since the second embodiment is similar to the first embodiment, only the differences will be illustrated hereafter. In this embodiment, a display device2includes a controller400electrically connected to multiple micro light emitting semiconductors120.

In detail, the controller400is disposed on a substrate110of a display panel100. The controller400is electrically connected to the micro light emitting semiconductors120, a light modulation unit220and an optical sensor300via a circuit structure (not shown in the drawing). The circuit structure may be a transparent conductive pattern. The display panel100and the light modulation panel200shares the controller400which controls the transmittance of the light modulation unit220of the light modulation panel200. In this embodiment, the controller400is disposed on the substrate110, but the present disclosure is not limited thereto. In some other embodiments, the controller is disposed on a support210or a suitable position in the display device where the controller works normally.

The controller400receives the intensity of ambient light from the optical sensor300. The controller400compares the intensity of ambient light with the predetermined intensity of ambient light to generate a result of the comparison. The controller400receives a drive current intensity from the micro light emitting semiconductors120. The controller400compares the drive current intensity in the micro light emitting semiconductors120with a predetermined drive current intensity to generate another result of the comparison. Further, the controller400generates the light modulation control signal according to the two results of the comparison. The values of the predetermined intensity of ambient light and the predetermined drive current intensity are stored in a memory medium of the controller400or an external memory medium (not shown in the drawings) electrically connected to the controller400.

The light modulation control signal is transmitted from the controller400through the circuit structure into the light modulation unit220in order to adjust the transmittance of the light modulation unit220. In detail, when the intensity of ambient light is greater than the predetermined intensity of ambient light and the drive current intensity is less than the predetermined drive current intensity, the controller400generates the light modulation control signal to enhance the transmittance of the light modulation unit220. When the intensity of ambient light is greater than the predetermined intensity of ambient light and the drive current intensity is greater than the predetermined drive current intensity, the controller400generates the light modulation control signal to reduce the transmittance of the light modulation unit220. When the intensity of ambient light is less than the predetermined intensity of ambient light and the drive current intensity is less than the predetermined drive current intensity, the controller400generates the light modulation control signal to reduce the transmittance of the light modulation unit220. When the intensity of ambient light is less than the predetermined intensity of ambient light and the drive current intensity is greater than the predetermined drive current intensity, the controller400generates the light modulation control signal to reduce the transmittance of the light modulation unit220.

In this embodiment, the light modulation panel200changes the transmittance of the light modulation unit220according to the light modulation control signal generated by the controller400. Thus, when the display device2is located in an environment with high intensity of ambient light and a high drive current intensity is provided in the micro light emitting semiconductor120(greater intensity of device light than a predetermined intensity of device light), the light modulation unit220is driven to the high transmittance state such that most amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200, thereby providing clear images. In the following three cases, the light modulation unit220is driven to the low transmittance state such that only a small amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200, thereby preventing a user from being uncomfortable due to overly bright images. The three cases are: the display device2is located in the environment with a high intensity of ambient light and a high drive current intensity is provided in the micro light emitting semiconductor120; the display device2is located in the environment with low intensity of ambient light and a high drive current intensity is provided in the micro light emitting semiconductor120; and the display device2is located in the environment with a low intensity of ambient light and a low drive current intensity is provided in the micro light emitting semiconductor120(less intensity of device light than the predetermined intensity of device light).

Moreover, the light modulation panel200of the display device2is used to adjust image brightness, such that the image brightness is changed according to the transmittance of the light modulation panel200. The intensity of device light emitted by the micro light emitting semiconductor120is only slightly changed by the drive current. Therefore, the adjustment of image brightness is less dependent on the drive current in the micro light emitting semiconductor120, such that an unreliable adjustment of image brightness due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor120is prevented.

In this embodiment, the display panel100and the light modulation panel200shares the controller400, but the present disclosure is not limited thereto. In some other embodiments, the display device includes multiple electrically connected controllers which are respectively configured to control the emission of light and the transmittance to generate drive current intensity.

FIG. 3is a cross-sectional view of a display device according to a third embodiment of the disclosure. Since the third embodiment is similar to the second embodiment, only the differences will be illustrated hereafter. In this embodiment, a display device3does not include any optical sensor equivalent to the optical sensor300.

In detail, in the display device3, a controller400is disposed on a substrate110of a display panel100. The controller400is electrically connected to multiple micro light emitting semiconductors120and a light modulation unit220via a circuit structure (not shown in the drawing). The display panel100and the light modulation panel200shares the controller400which controls the transmittance of the light modulation unit220of the light modulation panel200. In this embodiment, the controller400is disposed on the substrate110to have less influence on the display screen of the display panel100, but the present disclosure is not limited thereto. In some other embodiments, the controller is disposed on a support210or a suitable position in the display device where the controller works normally.

The controller400receives a drive current intensity from the micro light emitting semiconductors120which are electrically connected to the controller400. The controller400compares the drive current intensity with a predetermined drive current intensity to generate a light modulation control signal drive current intensity. The value of the predetermined drive current intensity is stored in a memory medium of the controller400or an external memory medium (not shown in the drawings) electrically connected to the controller400. The light modulation control signal is transmitted from the controller400through a circuit structure (not shown in the drawing) into the light modulation unit220in order to adjust the transmittance of the light modulation unit220. In detail, when the drive current intensity is greater the predetermined drive current intensity, the controller400generates the light modulation control signal to reduce the transmittance of the light modulation unit220. Thus, when the display device3displays an image with high brightness, the light modulation unit220of the light modulation panel200is favorable for preventing the light intensity of the micro light emitting semiconductors120from being overly high, thereby alleviating human eye irritation.

Moreover, the light modulation panel200of the display device3is used to adjust image brightness, such that the image brightness is changed according to the transmittance of the light modulation panel200. The intensity of device light emitted by the micro light emitting semiconductor120only slightly changed by a drive current. Therefore, the adjustment of image brightness is less dependent on the drive current in the micro light emitting semiconductor120, such that an unreliable adjustment of image brightness due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor120is prevented.

In this embodiment, the display panel100and the light modulation panel200shares the controller400, but the present disclosure is not limited thereto. In some other embodiments, the display device includes multiple electrically connected controllers which are respectively configured to control the emission of light and the transmittance to generate drive current intensity.

FIG. 4is a cross-sectional view of a display device according to a fourth embodiment of the disclosure. In this embodiment, a display device4includes a display panel100, a light modulation panel200, two optical sensors300, two controllers400and a light modulation panel500.

Since the fourth embodiment is similar to the first embodiment, only the differences will be illustrated hereafter. The display panel100of the display device4defines a first pixel area A and a second pixel area B in a direction parallel to an extension of a display surface of the display panel100. The first pixel area A is connected to the second pixel area B. Both the first pixel area A and the second pixel area B have a size equal to a single pixel or multiple pixels.

The light modulation panel200and the light modulation panel500are respectively disposed in the first pixel area A and the second pixel area B. In detail, the light modulation panel200is disposed on a section of a light emitting surface of the display panel100in the first pixel area A, and the light modulation panel500is disposed on another section of the light emitting surface in the second pixel area B. Both of the light modulation panels200and500have a similar configuration to the light modulation panel200in the aforementioned embodiments. The light modulation panel200and the light modulation panel500are disposed on two different portions of a support, respectively.

The two optical sensors300are disposed in the first pixel area A and the second pixel area B, respectively. The two controllers400are also disposed in the first pixel area A and the second pixel area B, respectively. In this embodiment, the arrangement and operation between the optical sensor300and the controller400in both the first pixel area A and the second pixel area B are similar to the optical sensor300and the controller400in the first embodiment. In an embodiment where a display device includes multiple light modulation panels, the arrangement and operation between the optical sensor and the controller are similar to the optical sensor300and the controller400in the second embodiment.

In addition to the advantages mentioned in the first through the third embodiments, since the light modulation panel200and the light modulation panel500respectively correspond to the first pixel area A and the second pixel area B, the transmittance of the light modulation panel200and the transmittance of the light modulation panel500are changeable independently. Thus, it is favorable for individually adjusting the brightness of two regions in an image which is respectively in the first pixel area A and the second pixel area B, thereby obtaining better image quality.

In this embodiment, the display device4includes both the optical sensor300and the controller400, but the present disclosure is not limited thereto. In some other embodiments, the display device includes a controller but does not include the optical sensor, and the arrangement and operation of the controller are similar to the controller400in the third embodiment. Thus, it is favorable for two light modulation panels adjusting the brightness of two regions in an image which is respectively in the first pixel area A and the second pixel area B, thereby obtaining better image quality.

FIG. 5is a cross-sectional view of a display device according to a fifth embodiment of the disclosure. In this embodiment, a display device5includes a display panel100and a light modulation panel200′.

The display panel100includes a substrate110, multiple micro light emitting semiconductors120and a protection layer130. Since the fifth embodiment is similar to the first embodiment, only the differences will be illustrated hereafter.

The light modulation panel200′ is disposed on a light emitting surface of the display panel100. The light modulation panel200′ includes a support210, a light modulation unit220′ and a protection layer250. The support210, for example, is a transparent glass plate or a transparent polymer plate. The light modulation unit220′ is disposed on a surface of the support210facing toward the display panel100. The light modulation unit220′ includes a photochromic material. When energy applied to the light modulation unit220′ by ambient light (that is, the intensity of ambient light) is changed, the transmittance of the light modulation unit220′ is changed according to the intensity of ambient light. The transmittance of the light modulation unit220′ has a positive correlation or is proportional to the intensity of ambient light. There is a logarithmic relationship between the transmittance of the light modulation unit220′ and a sensitivity of the human eye to light.

The protection layer250is disposed on the support210, and the light modulation unit220′ is located between the protection layer250and the support210. The protection layer250is configured to protect the light modulation unit220′ so as to prevent influences on the light modulation unit220′ due to external air or water. The protection layer250, for example, is made of epoxy, silicon oxide or transparent polymer.

In this embodiment, the light modulation panel200′ is disposed on the light emitting surface of the display panel100, and a surface of the protection layer250away from the support210faces toward a surface of the protection layer130away from the substrate110, but the present disclosure is not limited thereto. In some other embodiments, the light modulation panel is disposed on the light emitting surface of the display panel, and a surface of the support away from the light modulation unit faces toward a surface of the protection layer away from the substrate.

The transmittance of the light modulation unit220′ is changed according to the intensity of ambient light. In detail, when a high intensity of ambient light is provided, the light modulation unit220′ is in a high transmittance state, such that most of the amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200′, thereby providing clear images. When a low intensity of ambient light is provided, the light modulation unit220′ is in a low transmittance state, such that only a small amount of light emitted by the micro light emitting semiconductors120is able to pass through the light modulation panel200′, thereby preventing an uncomfortable visual effect due to overly bright images.

Moreover, the light modulation panel200′ of the display device5is used to adjust image brightness, such that the image brightness is changed according to the transmittance of the light modulation panel200′. The intensity of device light emitted by the micro light emitting semiconductor120only slightly changed by the drive current. Therefore, the adjustment of image brightness is less dependent on the drive current in the micro light emitting semiconductor120, such that an unreliable adjustment of image brightness due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor120is prevented.

FIG. 6is a cross-sectional view of a display device according to a sixth embodiment of the disclosure. In this embodiment, a display device6includes a display panel100, a light modulation panel200′ and a light modulation panel500′.

Since the sixth embodiment is similar to the fourth embodiment, only the differences will be illustrated hereafter.

The light modulation panel200′ and the light modulation panel500′ are respectively disposed in a first pixel area A and a second pixel area B. In detail, the light modulation panel200′ is disposed on a section of a light emitting surface of the display panel100in the first pixel area A, and the light modulation panel500′ is disposed on another section of the light emitting surface in the second pixel area B. Both the light modulation panels200′ and500′ have a similar configuration to the light modulation panel200′ in the aforementioned embodiments. The light modulation panel200′ and the light modulation panel500′ are disposed on two different portions of a support210, respectively.

In addition to the advantages mentioned in the fifth embodiment, since the light modulation panel200′ and the light modulation panel500′ respectively correspond to the first pixel area A and the second pixel area B, the transmittance of the light modulation panel200′ and the transmittance of the light modulation panel500′ is changeable independently. Thus, it is favorable for individually adjusting the brightness of two regions in an image which is respectively in the first pixel area A and the second pixel area B, thereby obtaining better image quality.

According to the disclosure, the light modulation panel of the display device adjusts the transmittance of the light modulation unit, including the electrochromic material, according to the light modulation control signal. When the intensity of ambient light is greater than the predetermined intensity, the light modulation control signal drives the light modulation unit to high transmittance state; and when the intensity of ambient light is less than the predetermined intensity, the light modulation control signal drives the light modulation unit to low transmittance state. The transmittance of the light modulation unit is controlled by both the intensity of ambient light and the intensity of device light. The device light is emitted by the micro light emitting semiconductor, and the intensity of device light is determined according to the drive current in the micro light emitting semiconductor. Therefore, the image brightness is changed according to the transmittance of the light modulation panel, and the change of transmittance is dependent on a combination of the ambient light and the drive current in the micro light emitting semiconductor, thereby preventing an unreliable adjustment of the transmittance due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor.

Furthermore, the light modulation panel of the display device adjusts the transmittance of the light modulation unit, including the photochromic material, according to the intensity of ambient light, such that the transmittance of the light modulation unit has a positive correlation or is proportional to the intensity of ambient light. Therefore, the image brightness is changed according to the transmittance of the light modulation panel, and the change of transmittance is dependent on a combination of the ambient light and the drive current in the micro light emitting semiconductor, such that an unreliable adjustment of the transmittance due to the difficult control of the intensity of device light emitted by the micro light emitting semiconductor is prevented.

Moreover, when the display device includes two light modulation panels which respectively correspond to the first pixel area and the second pixel area of the display panel, the brightness of two different regions in an image, which is respectively in the first pixel area and the second pixel area, is adjusted individually, thereby obtaining better image quality.

The foregoing description, for the purpose of explanation, has been described with reference to specific embodiments; however, the embodiments were chosen and described in order to explain the principles of the disclosure and its practical applications, to thereby enable others skilled in the art to utilize the disclosure and various embodiments with various modifications as are suited to the particular use being contemplated. The embodiments depicted above and the appended drawings are exemplary and are not intended to be exhaustive or to limit the scope of the disclosure to the precise forms disclosed. Modifications and variations are possible in view of the above teachings.