Display device and control method

Abstract

The present application provides a kind of in display device realizes further improved technology.In display device (1), display part (10) has the display region of display display image and the peripheral region surrounding display region.Control circuit (20) obtains illumination from the illumination of detecting incident light illumination sensor (22), and control display part (10).Display region contains as the region located near the peripheral region first end region.Control circuit (20) is based on the illumination and the image data of display image, derives as the brightness ratio of the brightness of first end region and the brightness of peripheral region brightness ratio.Control circuit (20) in the case where brightness ratio is greater than as specified value brightness ratio threshold value, control display part (10), to make brightness ratio become below brightness ratio threshold value.

Description

Technical Field

[0001] This disclosure relates to display devices and control methods. Background Technology

[0002] Image display devices that adaptively control image signal processing and display brightness are known (see, for example, Patent Document 1). The image display device detects changes in ambient illuminance and image features such as the average brightness of the input image. When illuminance changes rapidly and significantly, the image display device calculates an adaptive target characteristic using a prescribed LPF (Light Per Filter) operation, taking into account the detected illuminance changes. Using this adaptive target characteristic as a target value, the image display device adaptively controls image signal processing and display brightness while considering the image features of the input image.

[0003] [Prior art literature]

[0004] [Patent Documents]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-285064 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] Further improvements are sought in display devices.

[0008] [Technical solutions used to address technical problems]

[0009] To address the aforementioned issues, one aspect of the present disclosure includes a display device comprising: a display unit having a display area for displaying a displayed image and a peripheral area surrounding the display area; and a control circuit that acquires illuminance from an illuminance sensor that detects the illuminance of incident light and controls the display unit. The display area includes a first end area located near the peripheral area. Based on the illuminance and image data of the displayed image, the control circuit derives a luminance ratio, which is the ratio of the luminance of the first end area to the luminance of the peripheral area. If the luminance ratio is greater than a predetermined luminance ratio threshold, the control circuit controls the display unit to bring the luminance ratio below the luminance ratio threshold.

[0010] Another aspect of this disclosure is a control method. This method is a control method for a display device, which includes a display area having a display image and a peripheral area surrounding the display area. The display area includes a first end area, which is located near the peripheral area. The method includes: obtaining illuminance from an illuminance sensor that detects the illuminance of incident light; deriving a luminance ratio, which is the ratio of the luminance of the first end area to the luminance of the peripheral area, based on the illuminance; and controlling the display unit to bring the luminance ratio below the luminance ratio threshold if the luminance ratio is greater than a predetermined value.

[0011] [Invention Effects]

[0012] The above plan can achieve further improvements. Attached Figure Description

[0013] Figure 1 This is a diagram showing the configuration of the display device according to the implementation method.

[0014] Figure 2 yes Figure 1 A top view of the display section.

[0015] Figure 3 It is along Figure 2 The longitudinal section view of the display section along line III-III.

[0016] Figure 4 It means incident on Figure 3 A graph showing the brightness of various locations on the display unit under relatively high external light illuminance.

[0017] Figure 5 It means incident on Figure 3 A graph showing the brightness of various positions on the display unit before image correction, under conditions where the external light illuminance of the display unit is relatively low.

[0018] Figure 6 It means incident on Figure 3 A graph showing the brightness of the image at various locations on the display unit after image correction, under conditions where the external light illuminance of the display unit is relatively low.

[0019] Figure 7 This diagram illustrates the image brightness reduction process used to depict the central image.

[0020] Figure 8 It is used for explanation Figure 7 The graph displays the correction values ​​in the image.

[0021] Figure 9 It is a diagram used to illustrate the correction values ​​in other displayed images.

[0022] Figure 10 This is a diagram used to illustrate the image brightness reduction process for the overall image.

[0023] Figure 11 It means incident on Figure 1 A diagram showing the brightness of each position of the display unit before correction, under the condition that the external light illuminance of the display unit is relatively low and the second end area is displayed in black.

[0024] Figure 12 It indicates that the incident light is at the point where the light is incident on the ground. Figure 1A diagram showing the corrected brightness of each position of the display unit when the external light illuminance of the display unit is relatively low and the second end area is displayed in black.

[0025] Figure 13 This is a graph used to illustrate the correction values ​​in the light intensity reduction process.

[0026] Figure 14 It is a diagram used to illustrate the correction values ​​in other displayed images.

[0027] Figure 15 It means Figure 1 The flowchart of the control circuit processing.

[0028] [Explanation of reference numerals in the attached figures]

[0029] 1…display device, 10…display unit, 12…display panel, 14…backlight, 16…light source, 17…surface layer, 17a…first part, 17b…second part, 17c…third part, 18…decorative layer, 20…control circuit, 22…illuminance sensor, 24…end light source group, 30…feature detection unit, 32…first acquisition unit, 34…second acquisition unit, 36…export unit, 38…determination unit, 40…correction value generation unit, 42…image correction unit, 44…backlight control unit. Detailed Implementation

[0030] (The insights that form the basis of this disclosure)

[0031] Before describing the specific implementation, a basic insight will be explained. The inventors have discovered the following issue: In a display device in which a decorative layer is disposed on the observer side of a display panel, and the pattern of the decorative layer can be visually discerned in the display area where the image is displayed and in the surrounding area surrounding the display area, there is a possibility that the boundary between the display area and the surrounding area is easily visually discernible depending on the illuminance of the incident light onto the display device.

[0032] According to the inventors' research, when the illuminance of the incident light is relatively low, the luminance ratio near the boundary between the display area and the surrounding area—the ratio of the luminance of the display area to the luminance of the surrounding area—may be relatively large. When the luminance ratio near the boundary is large, the boundary between the display area and the surrounding area is easily visually discernible. Therefore, when the luminance ratio near the boundary is greater than a threshold, it is useful to control this luminance ratio below the threshold.

[0033] Hereinafter, the same or equivalent constituent elements, components, and processes shown in the various figures will be labeled with the same reference numerals, and repeated descriptions will be omitted where appropriate. In addition, the dimensions of the components in the figures are shown in appropriate enlargements or reductions for ease of understanding.

[0034] Figure 1The configuration of the display device 1 according to the embodiment is shown. An example of a vehicle-mounted display device will be described, but the application of the display device 1 is not particularly limited. The display device 1 may also be, for example, a display device for a portable electronic device or a display device for a stationary electronic device.

[0035] The display device 1 is, for example, located near the center of the central control console inside the carriage. The display device 1 displays various information. The display device 1 includes a display unit 10, a control circuit 20, and an illuminance sensor 22.

[0036] As the display unit 10, various devices for displaying images can be used. The display unit 10 displays images by emitting image light from the display surface. In this embodiment, the display unit 10 is described as an example of a liquid crystal display, but the display unit 10 can also be a self-emissive display such as an organic EL display.

[0037] The display unit 10 has a display panel 12 and a backlight 14. The display unit 10 also has a surface layer described later, but... Figure 1 The details are omitted. The display unit 10 may have known components such as optical sheets and protective layers (not shown).

[0038] Display panel 12 is a liquid crystal panel. Backlight 14 is a direct-lit backlight. Backlight 14 is located behind display panel 12 and illuminates display panel 12. Backlight 14 includes multiple light sources 16 that illuminate display panel 12. Each of the multiple light sources 16 is equipped with a light-emitting diode (LED) (not shown). The multiple light sources 16 are arranged, for example, in a matrix. Each light source 16 constitutes a light-emitting area. The multiple light sources 16 do not necessarily need to be arranged regularly; they can be arranged irregularly depending on the shape of display panel 12 or the displayed content. The brightness of each light source 16 can be controlled individually.

[0039] The control circuit 20 displays an image on the display panel 12 based on image data supplied from an external source via a liquid crystal driving circuit (not shown). The control circuit 20 controls the backlight 14 and the brightness of each light source 16 via a light source driving circuit (not shown).

[0040] The illuminance sensor 22 detects the illuminance of incident light onto the display unit 10 and outputs a signal representing the detected illuminance to the control circuit 20. Viewed from the observer's side, the illuminance sensor 22 is positioned next to the display panel 12. This allows it to detect the illuminance of external light incident on the display panel 12. The control circuit 20 controls the display unit 10 based on the illuminance detected by the illuminance sensor 22.

[0041] The control circuit 20 includes a feature detection unit 30, a first acquisition unit 32, a second acquisition unit 34, an output unit 36, a determination unit 38, a correction value generation unit 40, an image correction unit 42, and a backlight control unit 44. Details of the processing by the control circuit 20 will be described later. The configuration of the control circuit 20 can be implemented through the cooperation of hardware and software resources, or solely through hardware resources. Hardware resources can include microcomputers, CPUs, DSPs, ROMs, RAMs, ASICs, FPGAs, and other LSIs. Software resources can include firmware programs. In this embodiment, the functions of the feature detection unit 30, the first acquisition unit 32, the second acquisition unit 34, the output unit 36, the determination unit 38, the correction value generation unit 40, the image correction unit 42, and the backlight control unit 44 are realized through the operation of the control circuit 20.

[0042] Figure 2 yes Figure 1 A top view of the display section 10. Figure 2 This is a diagram of the display unit 10 viewed from the front side, i.e., the observer's side. Figure 3 It is along Figure 2 The longitudinal sectional view of the display section 10 along line III-III.

[0043] The display unit 10 has a display area A1 for displaying a display image and a peripheral area A2 surrounding the display area A1. The display area A1 is, for example, rectangular. The display area A1 corresponds to the display surface of the display panel 12. The display panel 12 displays the display image in the display area A1. No image is displayed in the peripheral area A2.

[0044] Display area A1 includes a first end area A11, which is located near the peripheral area A2. The first end area A11 is adjacent to the peripheral area A2. The first end area A11 has, for example, a rectangular frame shape. For example, the outermost pixels of the plurality of pixels in display panel 12 are located in the first end area A11. That is, viewed from the observer's side, the plurality of pixels in the topmost row, the bottommost row, the leftmost column, and the rightmost column of display panel 12 are located in the first end area A11. Figure 2 and Figure 3 In order to make the accompanying drawings clearer, the size of the first end region A11 has been exaggerated. Alternatively, multiple rows and columns of pixels may be located in the first end region A11.

[0045] Display area A1 includes a second end area A12, which is located near peripheral area A2 and includes the first end area A11. The second end area A12 is adjacent to peripheral area A2. The second end area A12 has, for example, a rectangular frame shape. As will be explained later, the size of the second end area A12 is determined by control circuit 20 based on the display image displayed in display area A1.

[0046] The displayed image includes the first end image displayed in the second end region 12. The first end image includes the second end image displayed in the first end region A11.

[0047] The backlight 14 has multiple light sources 16, which form an end light source group 24 consisting of multiple light sources 16 that overlap with the second end region A12. Figure 3 A portion of the light source 16 is shown in the image.

[0048] Surface layer 17 is translucent. Surface layer 17 covers at least a portion of display area A1 and at least a portion of peripheral area A2. In this embodiment, surface layer 17 covers the entire display area A1 and the entire peripheral area A2. Surface layer 17 is located on the observer side closer to the display panel 12 than the display panel 12. Viewed from the observer side, surface layer 17 is larger than the display panel 12. Viewed from the observer side, surface layer 17 is configured to completely overlap with the display panel 12. Viewed from the observer side, surface layer 17 has a portion overlapping the display panel 12, i.e., a first portion 17a overlapping the display area A1, and a portion not overlapping the display panel 12, i.e., a second portion 17b overlapping the peripheral area A2. The first portion 17a has a third portion 17c overlapping the first end area A11.

[0049] Surface layer 17 can be a plain panel or the like, or it can be a decorative layer 18. In this embodiment, surface layer 17 is decorative layer 18. Decorative layer 18 has, for example, a wood grain pattern and is translucent. Decorative layer 18 can be a patterned decorative sheet or a layer formed by printing or transferring ink onto a translucent cover (not shown).

[0050] The displayed image on the display panel 12 can be visually recognized from the observer's side via the decorative layer 18. The pattern of the decorative layer 18 can also be visually recognized from the observer's side, and the observer can visually recognize the pattern of the decorative layer 18 in the display area A1, overlapping with the displayed image. The observer can also visually recognize the pattern of the decorative layer 18 in the surrounding area A2. As a result, the appearance of the display device 1 can be improved. For example, by using the decorative layer 18 with a pattern that matches the interior decoration of a vehicle, the displayed image of the display device 1 can be integrated into the interior decoration of the vehicle.

[0051] like Figure 3As shown, if the brightness of the image light emitted from the display panel 12 is set to L (lm / sr / m²), 2 If the transmittance of the decorative layer 18 is set to T (%), then the brightness of the viewer-side surface of the decorative layer 18 of the displayed image in the display area A1 is LT / 100 (cd / m²). 2 )express.

[0052] If the illuminance of the external light incident on the decorative layer 18 is set to E (lm / m 2 Let the reflectivity of decorative layer 18 be R (%) and the reflectance coefficient of decorative layer 18 be k. Then the brightness of external light reflected by decorative layer 18 is EkR / 100 (cd / m²). 2 )express.

[0053] Therefore, the luminance of the observer-side surface of the decorative layer 18 in display area A1 is (LT+EkR) / 100 (cd / m²). 2 The luminance of the observer-side surface of decorative layer 18 in the surrounding area A2 is EkR / 100 (cd / m²). 2 ).

[0054] The following is for reference Figures 1 to 3 This will explain the processing of control circuit 20.

[0055] The first acquisition unit 32 acquires the illuminance E from the illuminance sensor 22. The second acquisition unit 34 acquires the brightness L of the second end image displayed on the first end region A11 from the image data of the displayed image. The brightness L of the second end image is, for example, the average brightness of a plurality of pixels in the first end region A11. The brightness of the pixels can be derived from the grayscale value of the pixels in the image data and the brightness of the backlight 14.

[0056] The output unit 36, based on the acquired illuminance E and the acquired luminance L of the second end image, derives a luminance ratio ((LT+EkR) / EkR), which is the ratio of the luminance of the first end region A11 to the luminance of the surrounding region A2. The luminance of the first end region A11 is, for example, the luminance of the observer-side surface of the third part 17c. The luminance of the surrounding region A2 is, for example, the luminance of the observer-side surface of the second part 17b. The luminance ratio is the ratio of the luminance of the first end region A11 to the luminance of the surrounding region A2. The luminance ratio is also called the contrast ratio. The values ​​of T, k, and R are pre-stored in a storage unit not shown.

[0057] The control circuit 20 determines whether the derived luminance ratio is greater than a predetermined luminance ratio threshold. If the luminance ratio is below the luminance ratio threshold, the control circuit 20 causes the display panel 12 to display the image according to the image data.

[0058] When the brightness ratio is greater than a brightness ratio threshold, the control circuit 20 controls the display unit 10 to bring the brightness ratio below the brightness ratio threshold. Specifically, the control circuit 20 controls the display panel 12 or the backlight 14 to bring the brightness ratio below the brightness ratio threshold.

[0059] The luminance ratio threshold is, for example, set to a value below 10. This threshold can be appropriately determined through experimentation or simulation. Generally, when the luminance ratio is below 10, the difference in brightness between display area A1 and the surrounding area A2 is difficult for an observer to discern, thus making the boundary between display area A1 and the surrounding area A2 difficult for the observer to visually identify. The closer the luminance ratio is to 1, the more difficult it is for the observer to visually identify the boundary between display area A1 and the surrounding area A2. The following illustrates an example with a luminance ratio threshold of 2.

[0060] When the brightness ratio is greater than the brightness ratio threshold, the control circuit 20 determines whether the brightness of the second end image is greater than the brightness threshold value set as a specified value.

[0061] A brightness threshold is a threshold used to determine whether the brightness ratio can be reduced by decreasing the brightness of the second-end image. The brightness threshold can be appropriately determined through experimentation or simulation. For example, when most of the pixels constituting the second-end image are displayed in black with the lowest grayscale value, the brightness threshold can be set such that the brightness of the second-end image is less than the brightness threshold. Similarly, when one of the pixels constituting the second-end image is displayed in black with the lowest grayscale value, the brightness threshold can also be set such that the brightness of the second-end image is less than the brightness threshold.

[0062] When the control circuit 20 determines that the brightness of the second end image is greater than a brightness threshold, it controls the display panel 12 to perform image brightness reduction processing to reduce the brightness of the first end image, so that the brightness ratio is below the brightness ratio threshold. The control circuit 20 performs image brightness reduction processing so that the brightness of the first end image gradually decreases from the center of the display area A1 toward the end of the display area A1.

[0063] When the control circuit 20 determines that the brightness of the second end image is below a brightness threshold, it controls the backlight 14 to perform a light intensity reduction process that reduces the light intensity of the end light source group 24, so that the brightness ratio is below the brightness ratio threshold. If it is difficult to reduce the brightness ratio by controlling the display panel 12, the brightness ratio can also be reduced by reducing the light intensity of the end light source group 24.

[0064] First, a specific example of image brightness reduction processing will be explained, and a specific example of light intensity reduction processing will be explained later.

[0065] Figure 4 Indicates incident on Figure 3The brightness of each position of the display unit 10 when the external light illuminance of the display unit 10 is relatively high. Figure 4 The position shown indicates Figure 3 The position in the left-right direction near the peripheral area A2 on the left and the second end area A12. Figure 4 The brightness shown is, for example, the brightness at various locations on the observer-side surface of the decorative layer 18. The same applies in the following figures.

[0066] Figure 4 This indicates that the brightness of the surrounding area A2 is 450 (cd / m²). 2 The brightness of the image displayed in display area A1 is 450 (cd / m²) regardless of position. 2 Example of ). In this case, since the brightness of display area A1 is 900 (cd / m²) regardless of position. 2 Therefore, the brightness of the first end region A11 is also 900 (cd / m²). 2 Therefore, the brightness ratio of the first end region A11 to the brightness of the surrounding region A2 is 900 / 450 = 2. Consequently, the boundary between the display region A1 and the surrounding region A2 is difficult for the observer to discern visually.

[0067] The determination unit 38 determines whether the luminance ratio derived by the output unit 36 ​​is greater than the luminance ratio threshold. If the luminance ratio is below the luminance ratio threshold, the image correction unit 42 does not correct the input image data and outputs the grayscale value of each pixel in the image data to the display panel 12. The multiple pixels of the display panel 12 are each controlled to have a transmittance corresponding to the grayscale value.

[0068] When the brightness ratio is below a threshold value, the backlight control unit 44 outputs a predetermined reference current value to the backlight 14. The reference current value is the predetermined brightness of each of the multiple light sources 16, for example, a value that enables the light to be emitted at maximum brightness. The reference current value flows through each of the multiple light sources 16 in the backlight 14.

[0069] Figure 5 Indicates incident on Figure 3 The brightness of the image at each position of the display unit 10 before correction when the external light illuminance of the display unit 10 is relatively low. Figure 5 The positions shown are... Figure 4 The positions shown correspond to each other. Figure 5 This indicates the brightness of the display unit 10 in dark conditions such as at night or inside a tunnel.

[0070] external light illuminance ratio Figure 4 The example is low, and the brightness of the surrounding area A2 decreases to 10 (cd / m²). 2 The brightness of the image displayed in display area A1 is... Figure 4 The same applies. In this case, the brightness of display area A1 is 460 (cd / m²) regardless of position. 2 Therefore, the brightness of the first end region A11 is also 460 (cd / m²). 2 Therefore, the brightness ratio of the first end region A11 to the brightness of the surrounding region A2 is 460 / 10 = 46. Thus, the difference in brightness between the display region A1 and the surrounding region A2 is easily discernible to the observer, and the boundary between the display region A1 and the surrounding region A2 is easily visually recognized by the observer.

[0071] In this example, the brightness of the second end image is assumed to be greater than a brightness threshold. The determination unit 38 determines whether the brightness of the second end image is greater than a predetermined brightness threshold. If both the brightness ratio and the brightness of the second end image are greater than the brightness threshold, the correction value generation unit 40 generates correction values ​​for each pixel of the first end image in a manner where the brightness of the first end image gradually decreases from the center of the display area A1 towards the end of the display area A1. The correction value generation unit 40 generates correction values ​​for each pixel of the second end image in a manner where the brightness of the second end image is reduced to a value equal to (brightness ratio threshold - 1) times the brightness of the peripheral area A2. The correction value generation unit 40 generates correction values ​​in a manner where the brightness of each pixel of the displayed image other than the first end image is not corrected. The correction value for each pixel of the displayed image other than the first end image is, for example, 1.

[0072] The image correction unit 42 multiplies the correction value of each pixel generated by the correction value generation unit 40 by the grayscale value of the corresponding pixel in the image data, and outputs the resulting grayscale values ​​of each pixel to the display panel 12. The processing performed by the correction value generation unit 40 and the image correction unit 42 is equivalent to image brightness reduction processing. Therefore, the brightness of each position on the display unit 10 is controlled to... Figure 6 The value shown.

[0073] Figure 6 Indicates incident on Figure 3 The brightness of the image at each position of the display unit 10 after correction when the external light illuminance of the display unit 10 is relatively low. Figure 6 The positions shown are also consistent with Figure 4 The positions shown correspond to each other.

[0074] Since the image displayed in display area A1, which is outside the second end area A12, is not corrected, its brightness is 450 (cd / m²) regardless of position. 2 The brightness of the second-end image displayed in the first-end region A11 is reduced to 10 (cd / m²) through correction. 2The brightness of the first end image displayed in the second end region A12 is reduced as it approaches the surrounding region A2 through correction. The brightness of the first end region A11 is 20 (cd / m²). 2 Therefore, the brightness ratio of the first end region A11 to the brightness of the surrounding region A2 is 20 / 10 = 2, which is equal to the brightness ratio threshold. Since the brightness ratio can be reduced to less than [a certain value] through correction... Figure 5 The values ​​shown make it difficult for an observer to visually discern the boundary between display area A1 and surrounding area A2. Furthermore, the brightness of the displayed image in display area A1, outside of the second end area A12, is... Figure 4 The same applies to the case where the visual recognizability of the displayed image is reduced, thus suppressing the decrease in visual recognizability.

[0075] Next, the image brightness reduction process will be explained in more detail.

[0076] The control circuit 20 determines whether the displayed image is a central image where only the central area contains information or an overall image where the entire image contains information, and determines the content of the image brightness reduction processing based on the determination result. Therefore, image brightness reduction processing corresponding to the type of displayed image can be performed. When the control circuit 20 determines that the displayed image is a central image, it performs image brightness reduction processing so that the brightness of the first end image decreases linearly from the center of the display area A1 towards the end of the display area A1. Figure 6 The aforementioned processing is performed when the displayed image is the central image.

[0077] The feature detection unit 30 detects features of the displayed image from the input image data. As features of the displayed image, the feature detection unit 30 detects, for example, the positions of edges and outputs the detected edge positions to the determination unit 38. Known techniques can be used in edge position detection. For example, the feature detection unit 30 converts the displayed image to grayscale, extracts multiple edges from the grayscale image, and detects the positions of the extracted multiple edges.

[0078] The determination unit 38 determines whether the displayed image is a central image or an overall image based on the position of the detected edge, and outputs the determination result to the correction value generation unit 40. If the edge is located only in the central region of the displayed image, and no edge exists in the areas outside the central region (i.e., the end regions), the determination unit 38 determines that the displayed image is a central image. The size of the central region is determined by the position of the outermost edge. If the edge exists at the ends of the displayed image, the determination unit 38 determines that the displayed image is an overall image.

[0079] Figure 7 This diagram illustrates the image brightness reduction process used to depict the central image. Figure 7(a) represents the display image displayed on display panel 12. Figure 7 (b) roughly represents Figure 7 (a) shows the brightness of the displayed image at various positions along line AA. The displayed image contains multiple icons 50 located in the central region A20. The end regions of the displayed image are the areas surrounding the central region where the multiple icons 50 are located, for example, displayed in white without any information. The end regions of the displayed image are located in the second end region A12.

[0080] Figure 7 (c) indicates the display of the image with Figure 7 (b) refers to the brightness correction values ​​for each position. When the brightness ratio is greater than a brightness ratio threshold, the brightness of the second end image is greater than a brightness threshold, and the displayed image is the central image, the correction value generation unit 40 generates correction values ​​for each pixel of the first end image in a manner that the brightness of the first end image linearly decreases from the center of the display area A1 towards the end of the display area A1. Based on the positions of multiple edges detected by the feature detection unit 30, the correction value generation unit 40 designates the area without edges as the second end area A12, thereby specifically displaying the first end image in the second end area A12.

[0081] Figure 7 (d) indicates the display of the image based on Figure 7 The corrected product of the correction value of (c) and (c) Figure 7 The brightness of each position corresponding to (b). Figure 7 (e) roughly represents and Figure 7 The corrected display image corresponds to the brightness shown in (d). In the corrected display image, since the brightness of the first end image decreases linearly, the brightness change of the first end image corresponding to the position is not obvious. On the other hand, the multiple icons 50 located outside the second end region A12 are displayed without brightness correction. That is, since the multiple icons 50 are displayed without reducing brightness, the reduction in visual recognizability of the multiple icons 50 can be suppressed.

[0082] Figure 8 It is used for explanation Figure 7 The graph displays the correction values ​​in the image. Figure 8 (a) represents Figure 7 (a) shows a portion of the display area A1. Pixel P1 is the leftmost pixel in the displayed image. Pixel P2 is the pixel located at the left edge of icon 50. Pixels P1 and P2 are in the same row.

[0083] Figure 8 (b) indicates the display of the image from Figure 8(a) shows the brightness before and after correction at the positions of pixels P1 to P2. The correction value generation unit 40 sets a reference line L1 with a predetermined slope at the position of pixel P1, based on the corrected brightness of pixel P1. The slope of the reference line L1 can be appropriately determined through experimentation or simulation. The slope of the reference line L1 is determined to satisfy the condition that the brightness at each position of the displayed image becomes a value on the reference line L1, thereby making brightness changes insignificant. The slope of the reference line L1 is, for example, 2 (cd / m²). 2 / 1 pixel). The slope of the reference line L1 is, for example, a fixed value independent of the displayed image.

[0084] When the brightness of pixel P2 before correction is below the value of the reference line L1 at the position of pixel P2, the correction value generation unit 40 generates a correction value such that the corrected brightness of each position between pixel P1 and pixel P2 is a value on the line connecting the corrected brightness of pixel P1 and the brightness before correction of pixel P2. Since the brightness of pixel P2 is not corrected, the correction value of pixel P2 is 1. In this case, since the slope of the line connecting the corrected brightness of pixel P1 and the brightness of pixel P2 is smaller than the slope of the reference line L1, the brightness change in the first end image is not obvious.

[0085] Figure 9 It is a diagram used to illustrate the correction values ​​in other displayed images. Figure 9 (a) indicates that the icon is 50 times higher than the previous one. Figure 8 The example shown in (a) is closer to the end of the display area A1. Figure 9 (b) indicates the display of the image from Figure 9 The brightness before and after correction at the positions of pixels P1 to P2 shown in (a) is shown. The pixel adjacent to pixel P2 in the second end region A12 is designated as pixel P3. Pixels P1, P2, and P3 are located in the same row.

[0086] If the brightness of pixel P2 before correction is greater than the value of the reference line L1 at the position of pixel P2, the correction value generation unit 40 generates a correction value such that the corrected brightness of each position between pixel P1 and pixel P3 is the value on the reference line L1. Since the brightness of pixel P2 is not corrected, the correction value of pixel P2 is 1. As a result, the brightness of the first end image decreases linearly from the center of the display area A1 toward the end of the display area A1. In this case, since the line connecting the corrected brightness of pixel P1 and the corrected brightness of pixel P3 is consistent with the reference line L1, the brightness change from pixel P1 to pixel P3 can be made less noticeable.

[0087] Furthermore, the slope of the reference line L1 can also be determined for each displayed image. For example, the slope of the reference line L1 can also be determined as the point of brightness at the position of pixel P2 obtained by multiplying the brightness of the first end region A11 by a brightness threshold.

[0088] Next, the image brightness reduction processing for the overall image will be explained focusing on the differences from the image brightness reduction processing for the central image. When the control circuit 20 determines that the displayed image is an overall image, it performs image brightness reduction processing so that the brightness of the first end image decreases non-linearly from the center of the display area A1 toward the end of the display area A1.

[0089] Figure 10 This is a diagram used to illustrate the image brightness reduction process for the overall image. Figure 10 (a) represents the display image displayed on display panel 12. Figure 10 (b) roughly represents Figure 10 The brightness of the displayed image at various positions along line BB is shown in (a). Here, an example is shown where the displayed image is a complete image of a map image displayed on the entire display panel 12. In the case of a complete image, the second end region A12 is predetermined. The second end regions A12 on the left and right sides each contain more than 1 / 10 of the number of pixels in the row direction of the display panel 12. The second end regions A12 on the top and bottom sides each contain more than 1 / 10 of the number of pixels in the column direction of the display panel 12.

[0090] Figure 10 (c) indicates the display of the image with Figure 10 (b) refers to the brightness correction values ​​for each position. When the brightness ratio is greater than a brightness ratio threshold, the brightness of the second end image is greater than a brightness threshold, and the displayed image is a whole image, the correction value generation unit 40 generates correction values ​​for each pixel of the first end image in a manner where the brightness of the first end image decreases non-linearly from the center of the display area A1 towards the end of the display area A1. The correction value generation unit 40 generates correction values ​​in a manner where the brightness of the first end image decreases more significantly as it approaches the end of the display area A1. The correction value generation unit 40 specifies the first end image within a predetermined second end region A12.

[0091] The correction value generation unit 40 generates correction values ​​for each pixel of the first end image, for example, using gamma correction. The correction value generation unit 40 is based on y=x γ The gamma curve represents the correction value between the correction value of pixel P1 and the correction value of pixel P2 in the generated image. γ is, for example, 1 / 2.2. (See also: Regarding...) Figure 5 and Figure 6 As explained, determine the correction value for pixel P1. The correction value for pixel P2 is 1.

[0092] Figure 10 (d) indicates the display of the image based on Figure 10 The corrected product of the correction value of (c) and (c) Figure 10 The brightness of each position corresponding to (b). Figure 10 (e) roughly represents and Figure 10 The corrected display image corresponds to the brightness shown in (d). In the corrected display image, the decrease in visual discernibility of the portion near the center of the display area A1 in the first end image can be suppressed. In addition, since the brightness of the area other than the second end area A12 is the same as the brightness before correction, the decrease in visual discernibility of the central area of ​​the display image can be suppressed.

[0093] Next, a specific example of light intensity reduction processing will be explained.

[0094] Figure 11 Indicates incident on Figure 1 The brightness of each position of the display unit 10 before correction when the external light illuminance of the display unit 10 is relatively low and the second end region A12 is displayed in black. Figure 11 For example, the brightness of the display unit 10 in dark conditions such as at night or in a tunnel.

[0095] Figure 11 This indicates that the brightness of the surrounding area A2 is 0.1 (cd / m²). 2 The brightness of the image displayed near the end of display area A1 is 2 (cd / m²) regardless of position. 2 Example of a display image. The grayscale value of each pixel in the image displayed near the end of display area A1 is the minimum value. The brightness of the second end image is below the brightness threshold. Each light source 16 of the backlight 14, including the end light source group 24, emits light at maximum brightness. Here, emitting light at maximum brightness by light source 16 is sometimes referred to as emitting light at 100% light intensity by light source 16. Sometimes, the current value that enables light source 16 to emit light at 100% light intensity is referred to as the 100% current value. The 100% current value is, in other words, the reference current value. Figure 11 In the example, each light source 16 is driven with 100% current.

[0096] In this case, the brightness of display area A1 is 2.1 (cd / m²) regardless of position. 2 Therefore, the brightness of the first end region A11 is also 2.1 (cd / m²). 2 Therefore, the brightness ratio of the first end region A11 to the brightness of the surrounding region A2 is 2.1 / 0.1 = 21. Therefore, in this state, the boundary between the display region A1 and the surrounding region A2 is easily visually discernible to the observer.

[0097] When reducing the light intensity, the second end region A12 is predetermined. For example, the second end region A12 can be used when the displayed image is a whole image.

[0098] Furthermore, in the unillustrated central area of ​​display area A1, icons, etc., can be displayed at, for example, hundreds (cd / m²). 2 (brightness display).

[0099] When the brightness ratio is greater than the brightness ratio threshold and the brightness of the second end image is less than the brightness threshold, the control circuit 20 performs light intensity reduction processing to gradually reduce the light intensity of the end light source group 24 from the center side of the display area A1 toward the end of the display area A1, for example, linearly.

[0100] Specifically, the correction value generation unit 40 generates a correction value for the current value of the end light source group 24 in such a way that the light intensity of the end light source group 24 decreases linearly from the center of the display area A1 toward the end of the display area A1. The correction value generation unit 40 generates a correction value in such a way that the brightness of the second end image is reduced to a value that is (brightness ratio threshold - 1) times the brightness of the peripheral area A2. The correction value generation unit 40 generates a correction value in such a way that the current value of the light source 16 other than the end light source group 24 remains unchanged.

[0101] The backlight control unit 44 corrects the reference current value by multiplying it by the correction value generated by the correction value generation unit 40, and outputs the corrected current value to the backlight 14. The processing performed by the correction value generation unit 40 and the backlight control unit 44 is equivalent to light intensity reduction processing. Therefore, the brightness of each position of the display unit 10 is controlled to... Figure 12 The value shown.

[0102] Figure 12 Indicates incident on Figure 1 The corrected brightness of each position of the display unit 10 when the external light illuminance of the display unit 10 is relatively low and the second end region A12 is displayed in black. Figure 12 The position shown is the same as Figure 11 The positions shown correspond to those shown.

[0103] In the end light source 16 at the end of the display area A1 in the end light source group 24, the current value used for driving is controlled to zero. Therefore, the end light source 16 at the end of the display area A1 in the end light source group 24 is turned off. In the light source 16 at the center of the display area A1 in the end light source group 24, the current value used for driving is controlled to 50% of the reference current value. Therefore, the light intensity of the light source 16 at the center of the display area A1 in the end light source group 24 is lower than 100%.

[0104] The brightness of the image displayed in display area A1 near the second end region A12 is 2 (cd / m²). 2 The brightness of the second-end image displayed in the first-end region A11 is reduced to 0.1 (cd / m²) through correction. 2 The brightness of the first end image displayed in the second end region A12 decreases as it approaches the surrounding region A2.

[0105] The brightness of the first end region A11 is 0.2 (cd / m²). 2 Therefore, the brightness ratio of the first end region A11 to the brightness of the surrounding region A2 is 0.2 / 0.1 = 2, which is equal to the brightness ratio threshold. Since the brightness ratio can be reduced to less than [a certain value] through correction... Figure 11 As shown, this makes it difficult for an observer to visually discern the boundary between display area A1 and surrounding area A2. Furthermore, since the brightness decreases linearly within the second end area A12, the brightness change of the corresponding first end image becomes less noticeable. Additionally, because the brightness of the displayed image in display area A1 outside the second end area A12 is... Figure 11 The same applies to the case where the visual recognizability of the displayed image is reduced, thus suppressing the decrease in visual recognizability.

[0106] Figure 13 This is a graph used to illustrate the correction values ​​in the light intensity reduction process. Figure 13 This represents the corrected brightness at the positions of pixels P1 to P2 in the second end region A12. The brightness of pixel P2 remains unchanged before and after correction.

[0107] The correction value generation unit 40 sets a reference line L1 at the position of pixel P1, representing the corrected brightness of pixel P1. The reference line L1 is, for example, the same as the reference line described in the image brightness reduction processing. When the uncorrected brightness of pixel P2 is lower than the value of the reference line L1 at the position of pixel P2, the correction value generation unit 40 generates correction values ​​such that the corrected brightness at each position between pixel P1 and pixel P2 is a value on the line connecting the corrected brightness of pixel P1 and the uncorrected brightness of pixel P2. In this case, since the slope of the line connecting the corrected brightness of pixel P1 and the brightness of pixel P2 is smaller than the slope of the reference line L1, the brightness change in the first end image is less noticeable.

[0108] Figure 14 It is a diagram used to illustrate the correction values ​​in other displayed images. Figure 14 This indicates that the grayscale value of pixel P2 is greater than... Figure 13 Example shown. The pixel adjacent to pixel P2 in the second end region A12 is designated as pixel P3.

[0109] If the brightness of pixel P2 before correction is greater than the value of the reference line L1 at the position of pixel P2, the correction value generation unit 40 generates a correction value such that the corrected brightness of each position between pixel P1 and pixel P3 is the value on the reference line L1. The brightness of pixel P2 is not corrected. As a result, the brightness of the first end image decreases linearly from the center of the display area A1 toward the end of the display area A1. In this case, since the line connecting the corrected brightness of pixel P1 and the corrected brightness of pixel P3 is consistent with the reference line L1, the brightness change from pixel P1 to pixel P3 can be made less noticeable.

[0110] Figure 15 It means Figure 1 The flowchart describes the processing of the control circuit 20. The control circuit 20 obtains the illuminance from the illuminance sensor 22 (S10). The control circuit 20 determines whether the luminance ratio is greater than a luminance ratio threshold (S12). If the control circuit 20 determines that the luminance ratio is not greater than the luminance ratio threshold (S12: No), the processing returns to S10. If the control circuit 20 determines that the luminance ratio is greater than the luminance ratio threshold (S12: Yes), the control circuit 20 determines whether the brightness of the second-end image is greater than a luminance threshold (S14). If the control circuit 20 determines that the brightness of the second-end image is not greater than the luminance threshold (S14: No), the control circuit 20 performs light intensity reduction processing (S16), and the processing returns to S10.

[0111] If the brightness of the second end image is determined to be greater than the brightness threshold (Yes in S14), the control circuit 20 determines whether the displayed image is the central image (S18). If the displayed image is determined to be the central image (Yes in S18), the control circuit 20 performs linear image brightness reduction processing (S20), and the processing returns to S10. If the displayed image is determined not to be the central image (No in S18), the control circuit 20 performs non-linear image brightness reduction processing (S22), and the processing returns to S10.

[0112] As described above, according to the embodiment, since the display unit 10 is controlled to make the brightness ratio below the brightness ratio threshold when the brightness ratio is greater than the brightness ratio threshold, the boundary between the display area A1 and the surrounding area A2 can be made difficult to visually distinguish.

[0113] The present disclosure has been described above based on the embodiments. Those skilled in the art should understand that the embodiments are merely illustrative, and there may be various modifications to the combination of the constituent elements or the processing procedures, and such modifications are also within the scope of the present disclosure.

[0114] For example, if the brightness ratio is greater than a brightness ratio threshold and the brightness of the second end image is greater than a brightness threshold, the control circuit 20 can control both the display panel 12 and the backlight 14 to perform image brightness reduction processing and light intensity reduction processing, so that the brightness ratio is below the brightness ratio threshold. In this modified example, the degree of freedom of control can be increased.

[0115] One embodiment of this disclosure is described below.

[0116] [Project 1]

[0117] A display device, comprising:

[0118] The display unit has a display area for displaying an image and a peripheral area surrounding the display area, and

[0119] A control circuit that obtains the illuminance from an illuminance sensor that detects the illuminance of incident light and controls the display unit;

[0120] The display area includes a first end region that is located near the surrounding area;

[0121] Based on the illuminance and the image data of the displayed image, the control circuit derives a luminance ratio, which is the ratio of the luminance of the first end region to the luminance of the surrounding region. If the luminance ratio is greater than a luminance ratio threshold value, the control circuit controls the display unit to make the luminance ratio below the luminance ratio threshold value.

[0122] According to this solution, since the display unit is controlled to make the brightness ratio below the brightness ratio threshold when the brightness ratio is greater than the brightness ratio threshold, the boundary between the display area and the surrounding area can be made difficult to be visually discerned.

[0123] [Project 2]

[0124] As described in Item 1, the display device

[0125] The display unit includes a surface layer covering at least a portion of the display area and at least a portion of the peripheral area;

[0126] The surface layer has a first portion that overlaps with the display area and a second portion that overlaps with the peripheral area;

[0127] The first portion has a third portion that overlaps with the first end region;

[0128] The brightness of the first end region is the brightness of the observer-side surface of the third part;

[0129] The brightness of the surrounding area is the brightness of the observer-side surface of the second part.

[0130] In this case, in a display device with a surface layer, the boundary between the display area and the surrounding area can be made difficult to visually discern.

[0131] [Project 3]

[0132] As described in Item 2, the display device

[0133] The surface layer is a patterned and translucent decorative layer.

[0134] In this case, the appearance of the display device can be improved.

[0135] [Project 4]

[0136] The display device described in any of items 1 to 3,

[0137] The display unit includes: a display panel for displaying the displayed image in the display area, and

[0138] A backlight comprising multiple light sources that illuminates the display panel;

[0139] When the brightness ratio is greater than the brightness ratio threshold, the control circuit controls at least one of the display panel and the backlight to make the brightness ratio fall below the brightness ratio threshold.

[0140] In this case, in a display device with a display panel and backlight, the boundary between the display area and the surrounding area can be made difficult to visually discern.

[0141] [Project 5]

[0142] As described in Item 4, the display device

[0143] The display area includes a second end area, which is located near the peripheral area and is an area that includes the first end area;

[0144] The displayed image includes the first end image displayed in the second end region;

[0145] When the brightness ratio is greater than the brightness ratio threshold, the control circuit controls the display panel to perform image brightness reduction processing to reduce the brightness of the first end image, so that the brightness ratio becomes below the brightness ratio threshold.

[0146] In this case, by reducing the brightness of the first end image, the brightness ratio can be reduced.

[0147] [Project 6]

[0148] As described in item 5, the display device

[0149] The first end image includes a second end image displayed in the first end region;

[0150] The control circuit determines whether the brightness of the second end image is greater than a predetermined brightness threshold. If the brightness of the second end image is determined to be greater than the brightness threshold, the image brightness is reduced.

[0151] In this case, the brightness ratio can be reduced by reducing image brightness.

[0152] [Project 7]

[0153] The display device described in item 5 or item 6,

[0154] The control circuit performs the image brightness reduction process to reduce the brightness of the first end image from the center of the display area toward the end of the display area.

[0155] In this case, the brightness change of the first end image corresponding to the position can be made less noticeable.

[0156] [Project 8]

[0157] The display device described in any of items 5 to 7,

[0158] The control circuit determines whether the displayed image is a central image where only the central area has information or an overall image where the entire image has information, and determines the content of the image brightness reduction processing based on the determination result.

[0159] In this case, image brightness reduction processing can be performed according to the type of image being displayed.

[0160] [Project 9]

[0161] As described in item 8, the display device

[0162] When the control circuit determines that the displayed image is the central image, it performs the image brightness reduction process so that the brightness of the first end image decreases linearly from the center of the display area toward the end of the display area.

[0163] In this case, the brightness change of the first end image corresponding to the position can be made less noticeable.

[0164] [Project 10]

[0165] The display device described in item 8 or 9

[0166] When the control circuit determines that the displayed image is the overall image, it performs the image brightness reduction process so that the brightness of the first end image decreases non-linearly from the center of the display area toward the end of the display area.

[0167] In this case, image brightness reduction processing can be performed in a way that suppresses the decrease in visual recognizability of the portion of the first end image near the central side of the display area.

[0168] [Project 11]

[0169] As described in Item 4, the display device

[0170] The display area includes a second end area, which is located near the peripheral area and is an area that includes the first end area;

[0171] The plurality of light sources have an end light source group consisting of a plurality of light sources arranged overlapping with the second end region;

[0172] When the brightness ratio is greater than the brightness ratio threshold, the control circuit performs a light intensity reduction process to reduce the light intensity of the end light source group, so that the brightness ratio becomes below the brightness ratio threshold.

[0173] In this case, the brightness ratio can be reduced by decreasing the light intensity of the end light source group.

[0174] [Project 12]

[0175] As described in item 11, the display device

[0176] The displayed image includes the first end image displayed in the second end region;

[0177] The first end image includes a second end image displayed in the first end region;

[0178] The control circuit determines whether the brightness of the second end image is below a predetermined brightness threshold. If the brightness of the second end image is determined to be below the brightness threshold, the light intensity reduction process is performed.

[0179] In this situation, even when it is difficult to reduce the brightness ratio by controlling the display panel, it is still possible to reduce the brightness ratio.

[0180] [Project 13]

[0181] The display device described in item 11 or item 12,

[0182] The control circuit performs the light intensity reduction process to reduce the light intensity of the end light source group from the center of the display area toward the end of the display area.

[0183] In this case, the brightness change of the first end image corresponding to the position can be made less noticeable.

[0184] [Project 14]

[0185] As described in item 13, the display device

[0186] The control circuit performs the light intensity reduction process so that the light intensity of the end light source group decreases linearly from the center of the display area toward the end of the display area.

[0187] In this case, the brightness change of the first end image corresponding to the position can be made less noticeable.

[0188] [Project 15]

[0189] The display device described in any of items 1 to 14,

[0190] Including the illuminance sensor.

[0191] In this case, a display device capable of detecting illuminance is provided.

[0192] [Project 16]

[0193] A control method for a display device.

[0194] The display device includes a display area for displaying a display image and a display portion surrounding the display area, wherein the display area includes a first end region that is located near the peripheral region;

[0195] The control method includes:

[0196] The step of obtaining the illuminance from an illuminance sensor that detects the illuminance of incident light.

[0197] The step of deriving the luminance ratio, which is the ratio of the luminance of the first end region to the luminance of the surrounding region, based on the illuminance, and

[0198] If the brightness ratio is greater than a predetermined brightness ratio threshold, the display unit is controlled to bring the brightness ratio below the brightness ratio threshold.

[0199] According to this solution, the boundary between the display area and the surrounding area can be made difficult to visually discern.

Claims

1. A display device, comprising: The display unit has a display area for displaying an image and a peripheral area surrounding the display area, and A control circuit that obtains the illuminance from an illuminance sensor that detects the illuminance of incident light and controls the display unit; The display area includes a first end region that is located near the surrounding area; Based on the illuminance and the image data of the displayed image, the control circuit derives a luminance ratio, which is the ratio of the luminance of the first end region to the luminance of the peripheral region. If the luminance ratio is greater than a luminance ratio threshold value, the control circuit controls the display unit to make the luminance ratio below the luminance ratio threshold value. The display unit includes a surface layer covering at least a portion of the display area and at least a portion of the peripheral area; The surface layer has a first portion that overlaps with the display area and a second portion that overlaps with the peripheral area; The first portion has a third portion that overlaps with the first end region; The brightness of the first end region is the brightness of the observer-side surface of the third part; The brightness of the surrounding area is the brightness of the observer-side surface of the second part.

2. The display device as described in claim 1, The surface layer is a patterned and translucent decorative layer.

3. The display device as described in claim 1, The display unit includes: a display panel for displaying the displayed image in the display area, and A backlight comprising multiple light sources that illuminates the display panel; When the brightness ratio is greater than the brightness ratio threshold, the control circuit controls at least one of the display panel and the backlight to make the brightness ratio fall below the brightness ratio threshold.

4. The display device as described in claim 3, The display area includes a second end area, which is located near the peripheral area and is an area that includes the first end area; The displayed image includes the first end image displayed in the second end region; When the brightness ratio is greater than the brightness ratio threshold, the control circuit controls the display panel to perform image brightness reduction processing to reduce the brightness of the first end image, so that the brightness ratio becomes below the brightness ratio threshold.

5. The display device as described in claim 4, The first end image includes a second end image displayed in the first end region; The control circuit determines whether the brightness of the second end image is greater than a predetermined brightness threshold. If the brightness of the second end image is determined to be greater than the brightness threshold, the image brightness is reduced.

6. The display device as described in claim 4 or 5, The control circuit performs the image brightness reduction process to reduce the brightness of the first end image from the center of the display area toward the end of the display area.

7. The display device as described in claim 4 or 5, The control circuit determines whether the displayed image is a central image where only the central area has information or an overall image where the entire image has information, and determines the content of the image brightness reduction processing based on the determination result.

8. The display device as claimed in claim 7, When the control circuit determines that the displayed image is the central image, it performs the image brightness reduction process so that the brightness of the first end image decreases linearly from the center of the display area toward the end of the display area.

9. The display device as claimed in claim 7, When the control circuit determines that the displayed image is the overall image, it performs the image brightness reduction process so that the brightness of the first end image decreases non-linearly from the center of the display area toward the end of the display area.

10. The display device as claimed in claim 3, The display area includes a second end area, which is located near the peripheral area and is an area that includes the first end area; The plurality of light sources have an end light source group consisting of a plurality of light sources arranged overlapping with the second end region; When the brightness ratio is greater than the brightness ratio threshold, the control circuit performs a light intensity reduction process to reduce the light intensity of the end light source group, so that the brightness ratio becomes below the brightness ratio threshold.

11. The display device as claimed in claim 10, The displayed image includes the first end image displayed in the second end region; The first end image includes a second end image displayed in the first end region; The control circuit determines whether the brightness of the second end image is below a predetermined brightness threshold. If the brightness of the second end image is determined to be below the brightness threshold, the light intensity reduction process is performed.

12. The display device as claimed in claim 10 or 11, The control circuit performs the light intensity reduction process to reduce the light intensity of the end light source group from the center of the display area toward the end of the display area.

13. The display device as claimed in claim 12, The control circuit performs the light intensity reduction process so that the light intensity of the end light source group decreases linearly from the center of the display area toward the end of the display area.

14. The display device as claimed in claim 1, Including the illuminance sensor.

15. A control method for a display device. The display device includes a display area for displaying a display image and a display portion surrounding the display area, wherein the display area includes a first end region that is located near the peripheral region; The control method includes: The step of obtaining the illuminance from an illuminance sensor that detects the illuminance of incident light. The step of deriving the luminance ratio, which is the ratio of the luminance of the first end region to the luminance of the surrounding region, based on the illuminance, and When the brightness ratio is greater than a predetermined brightness ratio threshold, the step of controlling the display unit to make the brightness ratio below the brightness ratio threshold is performed. The display unit includes a surface layer covering at least a portion of the display area and at least a portion of the peripheral area; The surface layer has a first portion that overlaps with the display area and a second portion that overlaps with the peripheral area; The first portion has a third portion that overlaps with the first end region; The brightness of the first end region is the brightness of the observer-side surface of the third part; The brightness of the surrounding area is the brightness of the observer-side surface of the second part.

Images