Display device and display control method

Abstract

To suppress image disturbance in use of an onscreen display.SOLUTION: A display device comprises a display screen and a signal processing unit which displays an item and superimposes and displays on the item a cursor (CSR) indicating that the item is selected, in the display screen. The signal processing unit displays the cursor in such a manner of preventing the ratio of the length of the cursor to the length of the item in a horizontal scanning direction of the display screen from exceeding a predetermined ratio.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a display device and a display control method. [Background technology]

[0002] An on-screen display is sometimes used in display devices, in which a predetermined image showing a setting menu or the like is displayed superimposed on an input image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-313263 [Patent Document 2] JP 2004-317823 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an on-screen display, depending on the size of the predetermined images to be superimposed, the superimposing process may not be able to keep up with the output of the image, resulting in distortion of the displayed image. This type of concern has become more pronounced with the increase in the number of pixels on display screens in recent years.

[0005] An object of the present invention is to provide a display device and a display control method that contribute to proper image display. [Means for solving the problem]

[0006] A first display device according to the present invention comprises a display screen and a signal processing unit that displays an item on the display screen and superimposes a cursor indicating that the item has been selected on the item, and the signal processing unit displays the cursor such that the ratio of the length of the cursor to the length of the item in the horizontal scanning line direction of the display screen does not exceed a predetermined ratio.

[0007] A second display device of the present invention comprises a display screen and a signal processing unit which displays an item on the display screen and superimposes a cursor indicating that the item has been selected on the item, and when the length of the item in the horizontal scanning line direction of the display screen is equal to or less than a predetermined value, the signal processing unit causes the length of the cursor to follow the length of the item, and when the length of the item in the horizontal scanning line direction of the display screen exceeds the predetermined value, the signal processing unit does not cause the length of the cursor to follow the length of the item but limits the length of the cursor to equal to or less than the predetermined value.

[0008] A third display device according to the present invention comprises a display screen and a signal processing unit that generates a display image for the display screen by superimposing an OSD image on an input image, and when multiple OSD images are superimposed on the same horizontal scanning line, the signal processing unit generates the display image such that the sum of the lengths of the multiple OSD images on the same horizontal scanning line does not exceed a predetermined value. Effect of the Invention

[0009] According to the present invention, it is possible to provide a display device and a display control method that contribute to proper image display. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic overall configuration diagram of a display device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing an overview of an on-screen display (OSD) function according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a layer structure employed in a display device according to an embodiment of the present invention. [Figure 4] 1A to 1C are diagrams showing examples of an input image, a menu image, and a composite image thereof according to an embodiment of the present invention. [Diagram 5] 11A to 11C are diagrams showing a transition of the display contents of a menu image in response to a user operation according to the embodiment of the present invention. [Figure 6] FIG. 4 is an exploded view of a menu image according to an embodiment of the present invention. [Figure 7] FIG. 11 is a diagram illustrating a configuration of a background image included in a menu image according to the embodiment of the present invention. [Figure 8] FIG. 4 is a configuration diagram of a menu image according to the embodiment of the present invention. [Figure 9] 10A and 10B are diagrams illustrating a relationship between a background image and a cursor in a menu image according to an embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing a menu image according to a reference example. [Figure 11] FIG. 13 is a diagram showing image distortion in a reference example. [Figure 12] FIG. 2 is an explanatory diagram of the shape and length of a cursor according to a first embodiment of the present invention. [Figure 13] FIG. 11 is an explanatory diagram of the shape and length of a background image of a menu image according to a first embodiment of the present invention. [Figure 14] 13 is an explanatory diagram of the shape and length of a cursor according to a second embodiment of the present invention. FIG. [Figure 15] FIG. 11 is a diagram showing a plurality of types of cursors having different lengths according to a second embodiment of the present invention. [Figure 16] FIG. 11 is a diagram showing a plurality of types of background images having different lengths according to a second embodiment of the present invention. [Figure 17] FIG. 11 is a diagram showing two composite images according to a second embodiment of the present invention. [Figure 18] FIG. 11 is a diagram showing two other composite images according to the second embodiment of the present invention. [Figure 19] 13A to 13C are diagrams showing two composite images according to a modified method of the second embodiment of the present invention. [Figure 20] 13A to 13C are diagrams showing two other composite images according to a modified method of the second embodiment of the present invention. [Figure 21]FIG. 13 is a diagram showing the relationship between a cursor having a frame shape and a background image, according to a modification method of a second embodiment of the present invention. [Figure 22] FIG. 11 is a diagram illustrating a situation in which multiple OSD images are located on the same horizontal scanning line according to a third embodiment of the present invention. [Figure 23] FIG. 11 is a diagram illustrating a situation in which multiple OSD images are located on the same horizontal scanning line according to a third embodiment of the present invention. [Figure 24] FIG. 11 is a diagram showing a state in which OSD images are arranged across a plurality of layers according to a third embodiment of the present invention. [Diagram 25] FIG. 13 is a diagram showing an OSD image according to a fourth embodiment of the present invention. [Figure 26] FIG. 26 relates to a fourth embodiment of the present invention and is a diagram showing image synthesis using the OSD image of FIG. 25. [Figure 27] FIG. 13 is a diagram showing a plurality of font images as an OSD image according to a fifth embodiment of the present invention. [Figure 28] FIG. 13 is a diagram showing an OSD image according to a fifth embodiment of the present invention. [Figure 29] FIG. 29 relates to a fifth embodiment of the present invention and is a diagram showing image synthesis using the font image in FIG. 27 and the OSD image in FIG. 28. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings. In each of the drawings, the same parts are given the same reference numerals, and duplicated descriptions of the same parts are generally omitted. In this specification, for the sake of simplicity, a symbol or code referring to information, a signal, a physical quantity, or a member may be written, and the name of the information, signal, physical quantity, or member corresponding to the symbol or code may be omitted or abbreviated.

[0012] 1 shows a schematic configuration diagram of a display device 1 according to an embodiment of the present invention. The display device 1 includes an input image supply unit 10, a video IC 20 which is an example of a signal processing unit, a display unit 30, a memory 40, a control unit 50, and an operation unit 60. The video IC 20 includes a buffer memory 21. The display unit 30 includes a driver 31 and a display screen 32.

[0013] The input image supply unit 10 supplies the video IC 20 with an input image that is the source of the display image of the display screen 32. Supplying the input image to the video IC 20 specifically means supplying image information AA representing the input image to the video IC 20. The input image supply unit 10 itself may generate the image information AA. Alternatively, the input image supply unit 10 may obtain the image information AA from a device or recording medium not shown. The input image may be a still image, but in the following, the input image is assumed to be a moving image having a predetermined frame rate. Therefore, the display image of the display screen 32 is also a moving image having a predetermined frame rate.

[0014] The video IC 20 generates a video signal CC based on the image information AA, and supplies the video signal CC to the display unit 30 to display an image based on the image information AA on the display screen 32. In the following description, unless otherwise specified, "display" refers to a display on the display screen 32, and a "display image" refers to an image displayed on the display screen 32. The video IC 20 is composed of an integrated circuit suitable for processing video signals. The video signal CC is transmitted from the video IC 20 to the display unit 30 by, for example, LVDS (Low Voltage Differential Signaling). However, the method of transmitting the video signal CC is arbitrary.

[0015] The video IC 20 has an on-screen display (hereinafter referred to as OSD) function. When the OSD function is used, an OSD image showing characters or the like is synthesized with an input image based on image information AA to generate a synthesized image. When a synthesized image is generated using the OSD function, a video signal CC representing the synthesized image is generated, and as a result, the synthesized image is displayed on the display screen 32. The synthesized image corresponds to an image in which the OSD image is superimposed on the input image. When the OSD function is not used, a video signal CC representing the input image itself is supplied to the display unit 30, and the input image itself is displayed on the display screen 32. In the OSD function, an image held by the video IC 20 may be synthesized with the OSD image instead of the input image supplied from the input image supply unit 10.

[0016] In the display unit 30, the driver 31 receives the video signal CC and drives the display screen 32 based on the video signal CC. As a result, an image based on the video signal CC is displayed on the display screen 32. The type of display element constituting the display screen 32 is arbitrary. The display screen 32 is, for example, a liquid crystal display panel or an organic EL display panel. EL is an abbreviation for "Electro Luminescence". An ASIC (Application Specific Integrated Circuit) that performs necessary signal processing on the video signal CC output from the video IC 20 may be provided. In this case, the video signal CC after the signal processing is supplied to the driver 31, and an image based on the video signal CC is displayed on the display screen 32. The ASIC can be considered to be provided between the video IC 20 and the display unit 30, or can be considered to be provided in the display unit 30.

[0017] The memory 40 is a non-volatile memory such as a flash memory. Image information BB representing an OSD image is stored in a non-volatile manner in the memory 40. The video IC 20 can read out the image information BB representing the OSD image from the memory 40. Reading out the image information BB from the memory 40 is achieved by communication between the video IC 20 and the memory 40. The communication between the video IC 20 and the memory 40 is, for example, communication by SPI (Serial Peripheral Interface). However, any communication method may be used between the video IC 20 and the memory 40.

[0018] The control unit 50 has a CPU (Central Processing Unit), a ROM (Read only memory), a RAM (Random access memory), etc., and has a function of controlling the overall operation of the display device 1. The CPU executes a program stored in the ROM of the control unit 50 or a program stored in a program memory (not shown), thereby realizing various functions of the control unit 50. Of the control functions of the control unit 50, attention is focused here on the control function for the video IC 20. The control unit 50 can control the operation of the video IC 20 based on operation information input from the operation unit 60.

[0019] The operation unit 60 receives various operations from the user, and outputs operation information corresponding to the operations received from the user to the control unit 50. The user refers to a user of the display device 1. The operation unit 60 may be an operation member attached to a housing in which the display unit 30 is provided, or may be a remote controller separated from the housing. The operation unit 60 may have a touch panel formed by using the display screen 32. In the following, it is considered that the operation unit 60 has buttons 61 to 64. The buttons 61 to 64 are four buttons forming a so-called cross key. The buttons 61 to 64 correspond to up, down, left, and right buttons, respectively. The user can input an operation of pressing the buttons 61 to 64 (pressing operation) to the operation unit 60.

[0020] The OSD function will now be explained. The process of generating a composite image by synthesizing an input image and an OSD image is hereinafter referred to as image synthesis processing. A video signal CC of the composite image is generated by the synthesis image processing. The synthesis image processing is realized by using a buffer memory 21. Figure 2 shows examples of an input image, an OSD image, and a composite image.

[0021] In the image synthesis process, a synthetic image is formed using a layer structure. The layer structure is shown in FIG. 3. The layer structure has 1st to nth layers, where n is an arbitrary integer equal to or greater than 2. The i-th layer and the (i+1)th layer are adjacent to each other, and the i-th layer is located above the (i+1)th layer (where i is an arbitrary natural number equal to or less than (n-1)). An image of a layer located relatively higher is superimposed on an image of a layer located relatively lower. In the synthetic image, the layer on which the OSD image is arranged is located above the layer on which the input image is arranged. Therefore, the synthetic image is an image in which the OSD image is superimposed on the input image.

[0022] The number of pixels in the vertical direction and the number of pixels in the horizontal direction in the display screen 32 are arbitrary, but for the sake of concrete explanation, it is assumed here that the display screen 32 has 1080 pixels in the vertical direction and 1920 pixels in the horizontal direction arranged in a matrix. Therefore, the number of scanning lines (which may also be called horizontal scanning lines) in the display screen 32 is 1080. In the display screen 32, the vertical direction corresponds to the vertical direction, and the horizontal direction corresponds to the horizontal direction. The vertical scanning frequency of the display screen 32 is, for example, 60 Hz (Hertz). The input image has an image size equal to the number of pixels in the display screen 32. That is, the input image has an image size of 1080 pixels in the vertical direction and 1920 pixels in the horizontal direction. In this embodiment, the horizontal direction is synonymous with the scanning line direction (which may also be called the horizontal scanning line direction), and the vertical direction is perpendicular to the horizontal direction.

[0023] Although the image synthesis process in the video IC 20 may be performed by a frame buffer method, it is assumed here that the image synthesis process is performed by a line buffer method, and therefore the buffer memory 21 is a line buffer. The buffer memory 21 as a line buffer has a memory capacity for one scanning line. In other words, the buffer memory 21 has a memory capacity sufficient to store image information for 1920 pixels.

[0024] In the image synthesis process, image information AA of the input image and image information BB of the OSD image read from memory 40 are synthesized in buffer memory 21 (line buffer), and the synthesis result is output as a video signal CC to display unit 30. Normally, an OSD image spans multiple scanning lines. Therefore, the process of synthesizing image information AA and BB in buffer memory 21 is performed sequentially for all scanning lines on which the OSD image is to be displayed.

[0025] When a predetermined operation is input to the operation unit 60, a menu image 600 is composited with an input image 510 as shown in Fig. 4, and a composite image 530 of the input image 510 and the menu image 600 is displayed on the display screen 32. The menu image 600 is a multi-window image made up of a plurality of OSD images. With the menu image 600 being displayed, the user can perform various settings for the display device 1. Although a test pattern image is shown as the input image 510 in Fig. 4, the input image 510 may be any input image.

[0026] The menu image 600 has a total of eight setting items F1 to F8, and the user selects one of the setting items F1 to F8 by operating the operation unit 60. The setting items F1 to F8 are arranged in a line in the vertical direction of the display screen 32. The menu image 600 has a cursor CSR (i.e., includes an image of the cursor CSR). When the up button 61 or the down button 62 is pressed while the menu image 600 is displayed, the video IC 20 moves the display position of the cursor CSR in the vertical direction based on operation information indicating the content of the press. This shows the user which of the setting items F1 to F8 has been selected (corresponding to transitions 551 or 552 in FIG. 5).

[0027] A unique setting target is assigned to each of the setting items F1 to F8. When a certain setting item is selected, pressing the left button 63 or the right button 64 changes the setting content of the setting target corresponding to the selected setting item (corresponding to transitions 553 or 554 in FIG. 5).

[0028] The setting target for the setting item F1 is the video mode of the display device 1. Therefore, when the setting item F1 is selected, the user can set the video mode of the display device 1 by pressing the button 63 or 64. The video IC 20 generates a video signal CC according to the setting content of the video mode of the display device 1. The setting targets for the setting items F2, F3, F4, and F5 are the brightness, contrast, hue, and color saturation of the display screen 32, respectively. Therefore, when the setting item F2 is selected, the user can set the brightness of the display screen 32 by pressing the button 63 or 64. The video IC 20 generates a video signal CC according to the setting content of the brightness of the display screen 32. Similarly, when the setting item F3 is selected, the user can set the contrast of the display screen 32 by pressing the button 63 or 64. The video IC 20 generates a video signal CC according to the setting content of the contrast of the display screen 32. The same applies when the setting item F4 or F5 is set. Although a detailed explanation is omitted, each of the setting items F6 to F8 is assigned a unique setting target.

[0029] FIG. 5 shows a transition 553 of the display contents when the left button 63 is pressed while the setting item F3 is selected, and a transition 554 of the display contents when the right button 64 is pressed. The menu image 600 has a marker associated with each setting item. In FIG. 5, the symbol MK3 is attached to the marker associated with the setting item F3. When the left button 63 is pressed while the setting item F3 is selected, the video IC 20 moves the displayed marker MK3 to the left by a unit distance and decreases the contrast of the display screen 32 by a predetermined amount. When the right button 64 is pressed while the setting item F3 is selected, the video IC 20 moves the displayed marker MK3 to the right by a unit distance and increases the contrast of the display screen 32 by a predetermined amount. Even when another setting item is selected, when the left button 63 or 64 is pressed, the display state of the corresponding marker is changed (the display position or the display content is changed) and the setting content of the setting target is changed.

[0030] 6 shows an exploded view of a menu image 600. The menu image 600 is made up of eight OSD images 610, 620, 630, 640, 650, 660, 670, and 680. A plurality of OSD images including the OSD images 610 to 680 are stored in the memory 40. Note that storage of an OSD image and storage of image information of an OSD image are synonymous.

[0031] The OSD image 610 corresponds to the background image of the menu image 600. Therefore, the OSD image 610 may also be referred to as the background image 610 hereinafter. As shown in FIG. 7, the background image 610 includes setting item images 611-618 representing setting items F1-F8. In the background image 610, the setting item images 611-618 are arranged vertically. In the composite image 530 (see FIG. 4), the input image 510 is arranged in the third layer, the background image 610 is arranged in the second layer, and the other seven OSD images 620-680 are arranged in the first layer. That is, in the display screen 32, the background image 610 is superimposed on the input image 510, and further, the OSD images 620-680 are superimposed on the background image 610.

[0032] Fig. 8 shows a menu image 600 that is a combination of eight OSD images 610 to 680. OSD images 620, 630, 640, and 650 are images that represent markers for setting items F2 to F5, respectively. The marker for setting item F3 corresponds to marker MK3 in Fig. 5. OSD images 620, 630, 640, and 650 are displayed superimposed on setting item images 612, 613, 614, and 615, respectively.

[0033] The OSD image 660 is an image that represents markers for the setting items F6 and F7. The setting contents of the setting items F6 and F7 are collectively expressed in the OSD image 660. Although a detailed description is omitted, the OSD image 660 shown in FIG. 6 is an OSD image when the setting content of the setting item F6 is set to "external light interlocking" and the setting content of the setting item F7 is set to "Yes". As shown in FIG. 7, in the background image 610, the characters "external light interlocking" and "navigation interlocking" are displayed in the setting item image 616, and the characters "Yes" and "No" are displayed in the setting item image 617. Although it is not clear from FIG. 6 and FIG. 7, the color of the characters in the setting item images 616 and 617 is gray, and the characters are not highlighted by displaying only the background image 610. The characters "external light interlocking" and "Yes" are highlighted by superimposing the OSD image 660 on the background image 610. 8, the characters "External light interlocking" and "Yes" are shown larger than other characters to express that these characters are highlighted (the same applies to other similar drawings). When "Navigation interlocking" and "No" are set for the setting items F6 and F7, an OSD image for highlighting "Navigation interlocking" and "No" is used instead of OSD image 660. The same applies to the state in which "External light interlocking" and "No" are set for the setting items F6 and F7, or the state in which "Navigation interlocking" and "Yes" are set for the setting items F6 and F7.

[0034] The OSD image 670 is an image showing a marker for the setting item F8. The setting item F8 is a setting item for setting the audio output state to any one of the first to fourth audio output states. Although a detailed description is omitted, the OSD image 670 shown in FIG. 6 is an OSD image when the audio output state is set to the second audio output state. As shown in FIG. 7, the character "OFF" and three types of icons are displayed in the setting item image 618 in the background image 610. Although it is not clear from FIG. 6 and FIG. 7, the character "OFF" and each icon in the setting item image 618 are gray in color, and the character "OFF" and each icon are not highlighted by displaying only the background image 610. By superimposing the OSD image 670 on the background image 610, one icon corresponding to the second audio output state among the above three types of icons is highlighted. When the third or fourth audio output state is set as the audio output state, an OSD image for highlighting other icons is used instead of the OSD image 670. When the first audio output state is set as the audio output state, an OSD image for highlighting the characters “OFF” is used instead of the OSD image 670.

[0035] There are a plurality of types of background images for the menu image 600, and one of the plurality of types of background images is set as the background image for the menu image 600 according to the setting contents of the setting item F1. There are four modes called "normal", "soft", "dynamic" and "cinema" as the setting contents of the video mode. The OSD image 610 in FIG. 6 and FIG. 7 is the background image when the "normal" mode is set as the video mode. In the OSD image 610, among the characters "normal", "soft", "dynamic" and "cinema", only the character "normal" has a specific color different from the other characters, and by using the OSD image 610 as the background image for the menu image 600, only the character "normal" is highlighted. When the "soft" mode is set as the video mode, an OSD image in which the character "soft" has a specific color instead of the character "normal" as seen from the OSD image 610 is used as the background image for the menu image 600, and as a result, only the character "soft" is highlighted. The same is true when the "Dynamic" or "Cinema" mode is set as the video mode. In the setting item F1, a change in the highlighted characters among the characters "Normal", "Soft", "Dynamic" and "Cinema" can be understood to correspond to a change in the position of the marker for the setting item F1.

[0036] The OSD image 680 is the cursor CSR (image of the cursor CSR). The menu image 600 in Fig. 8 is a menu image in a state where the setting item F3 corresponding to contrast is selected. When the composite image 530 is displayed, the cursor CSR is displayed at a position associated with the selected setting item among the setting items F1 to F8.

[0037] When the setting item F3 is selected, the cursor CSR (i.e., OSD image 680) is placed at a predetermined position in the setting item image 613 as shown in Fig. 9(a), and is therefore superimposed on the setting item image 613 (i.e., the cursor CSR is superimposed on the setting item F3). The cursor CSR (i.e., OSD image 680) superimposed on the setting item image 613 functions as a cursor indicating that the setting item F3 is selected. Note that Fig. 9(a) shows only the composite result of the background image 610 and the cursor CSR (the same applies to Figs. 9(b) and (c) described below).

[0038] When the up button 61 is pressed while the setting item F3 is selected, the state transitions to a state where the setting item F2 is selected (corresponding to transition 551 in FIG. 5), and the video IC 20 shifts the display position of the cursor CSR (i.e., OSD image 680) into the setting item image 612. When the setting item F2 is selected, the cursor CSR (i.e., OSD image 680) is placed at a predetermined position within the setting item image 612 as shown in FIG. 9(b), and is therefore superimposed on the setting item image 612 (i.e., the cursor CSR is superimposed on the setting item F2). The cursor CSR (i.e., OSD image 680) superimposed on the setting item image 612 functions as a cursor indicating that the setting item F2 is selected.

[0039] When the down button 62 is pressed while the setting item F3 is selected, the state transitions to a state where the setting item F4 is selected (corresponding to transition 552 in FIG. 5), and the video IC 20 shifts the display position of the cursor CSR (i.e., OSD image 680) into the setting item image 614. When the setting item F4 is selected, the cursor CSR (i.e., OSD image 680) is placed at a predetermined position in the setting item image 614 as shown in FIG. 9(c), and is therefore superimposed on the setting item image 614 (i.e., the cursor CSR is superimposed on the setting item F4). The cursor CSR (i.e., OSD image 680) superimposed on the setting item image 614 functions as a cursor indicating that the setting item F4 is selected.

[0040] In this way, during the display period of the composite image including the menu image 600, the display position of the cursor CSR (i.e., the OSD image 680) changes in response to the pressing of button 61 or 62, and the display position of the cursor CSR indicates to the user which setting item is selected.

[0041] By the way, to obtain a composite image by superimposing an OSD image on an input image, a read time and a composite processing time are required. The read time is the time required to read image information BB of the OSD image from memory 40. The composite processing time is the processing time required to composite the read image information BB with image information AA of the input image in video IC 20. The read time depends on the image size of the OSD image to be read and on the communication speed between video IC 20 and memory 40.

[0042] If the communication speed between the video IC 20 and the memory 40 is insufficient compared with the output speed of the video signal CC from the video IC 20, the synthesis in the buffer memory 21 will not keep up, causing distortion in the image on the display screen 32. Also, if the total number of OSD images to be superimposed on the same horizontal scanning line increases, the synthesis processing time increases, and if this causes the synthesis in the buffer memory 21 to not keep up, distortion in the image on the display screen 32 will occur.

[0043] FIG. 10 shows a menu image 600' according to a reference example. In the reference example, the cursor CSR' has a shape of a frame surrounding the selected setting item, and the length of the cursor CSR' in the horizontal direction is approximately the same as the length of the menu image 600'. The cursor CSR' is understood to be a combination of two horizontal line segments parallel to the horizontal direction and two vertical line segments parallel to the vertical direction. Although it depends on the length of the menu image 600' in the horizontal direction, if the cursor CSR' is adopted when the length of the menu image 600' in the horizontal direction is relatively long, the synthesis process on the scanning line on which the horizontal line segments are located will not be able to keep up. Disturbances will occur in the image on the display screen 32. FIG. 11 shows an example of image disturbances that may occur when the menu image 600' according to the reference example is used. In FIG. 11, the image disturbances are simply expressed by hatching with diagonal lines.

[0044] The display device 1 employs a technology for avoiding such image disturbance. This technology or matters related to this technology will be described in the following several examples. The matters described above in this embodiment (excluding the reference example) are applied to each of the following examples unless otherwise specified and unless there is a contradiction. If there are matters in each example that contradict the matters described above, the description in each example may take precedence. Furthermore, unless there is a contradiction, matters described in any of the following several examples can also be applied to any of the other examples (i.e., any two or more of the multiple examples can be combined).

[0045] <<First Example>> A first embodiment will be described. The cursor CSR according to the first embodiment will be referred to as cursor CSR1. As shown in FIG. 12, the cursor CSR1 has the shape (external shape) of a line segment extending in the horizontal direction (horizontal scanning line direction). The length of the cursor CSR1 in the horizontal direction is represented by the symbol "L". CSR1 In the first embodiment, the length L CSR1 is fixed. The width of cursor CSR1 (i.e. the length of cursor CSR1 in the vertical direction) is L CSR1 is small enough for

[0046] Please refer to FIG. 13. The above-mentioned background image 610 is a rectangular image, and the horizontal length of the background image 610 is represented by the symbol "L F1 As described above, the background image 610 includes setting item images 611 to 618 representing the setting items F1 to F8. Each of the setting item images 611 to 618 is also a rectangular image, and here, the length of each setting item image in the horizontal direction is the length L of the background image 610. F1 shall be deemed to be consistent with

[0047] The horizontal length of an arbitrary image of interest is the horizontal length of the display area of ​​the image of interest, and is expressed in units of pixels. An example of an image of interest is the cursor CSR1 or background image 610. Assume that the 1st to 1920th pixels are arranged from left to right on each scanning line of the display screen 32. For example, if the image of interest is displayed using only the 100th to 179th pixels on one or more scanning lines, then the horizontal length of the image of interest is 80 pixels, since "179-100+1=80".

[0048] In the first embodiment, the length L F1 is assumed to be fixed at a predetermined length. Then, in order to prevent image distortion, the length L CSR1 The upper limit of the length L in the first embodiment is automatically determined. CSR1 is the predetermined upper limit L LIM1 The limit is set so as not to exceed “L CSR1 ≦L LIM1 ", the synthesis in the buffer memory 21 is completed in time, and no distortion occurs in the image on the display screen 32 (such that the upper limit value L LIM1 The upper limit L LIM1 The length indicated by is shorter than the entire horizontal length of the display screen 32 (the length of 1920 pixels).

[0049] Length L in Figure 13 F1 Under the assumption that "L CSR1 ≦L LIM1 " means that the length L F1 Length L for CSR1 The ratio is set to a predetermined upper limit R LIM1 This is equivalent to restricting the length L to F1 Length L for CSR1 The ratio of "(L CSR1 / L F1 )” and the upper limit ratio R LIM1 is "R LIM1 =L LIM1 / L F1 In other words, the video IC 20 according to the first embodiment has a ratio (L CSR1 / L F1 ) is the upper limit ratio RLIM1 The cursor CSR1 will be displayed so that it does not exceed “0 <R LIM1 <1" is true. For example, "0 <R LIM1 <0.5” or “0 <R LIM1 <0.3” is acceptable.

[0050] According to the first embodiment, since an appropriate limit is imposed on the length of the cursor, it is possible to avoid a situation where the image is distorted due to a delay in composition.

[0051] <<Second Example>> A second embodiment will now be described. The cursor CSR according to the second embodiment will be referred to as cursor CSR2. In the second embodiment, as shown in FIG. 14, the cursor CSR2 may have a shape (external shape) of a line segment extending in the horizontal direction (horizontal scanning line direction). The length of the cursor CSR2 in the horizontal direction is represented by the symbol "L". CSR2 When the shape of the cursor CSR2 is a line segment, the width of the cursor CSR2 (i.e., the length of the cursor CSR2 in the vertical direction) is the length L CSR2 is small enough for

[0052] In the second embodiment, the length L CSR2 15(a) to 15(c) show three cursors CSR2, ie, cursors CSR2_1, CSR2_2, and CSR2_3, which are different from each other in horizontal length. CSR2 In particular, the symbols "L CSR2_S ", "L CSR2_M ", "L CSR2_L " Here, "L CSR2_S <L CSR2_M <L CSR2_L" holds. To make it possible to display the cursors CSR2_1, CSR2_2, and CSR2_3, it is sufficient to store in the memory 40 a first cursor OSD image representing the cursor CSR2_1, a second cursor OSD image representing the cursor CSR2_2, and a third cursor OSD image representing the cursor CSR2_3. Then, depending on the length of the cursor CSR2 to be displayed, one of the first to third cursor OSD images is read out from the memory 40 and composited with the input image.

[0053] On the other hand, in the second embodiment, a plurality of types of background images with different horizontal lengths are prepared as background images for the menu image 600, and the menu image 600 including any of the plurality of types of background images can be selectively synthesized with the input image. The plurality of types of background images have a structure similar to the above-mentioned OSD image 610 (see FIG. 7), and attention is now focused on four background images included in the plurality of types of background images. FIG. 16 shows a schematic diagram of the four background images, OSD images 610_A, 610_B, 610_C, and 610_D.

[0054] Here, background images 610_A, 610_B, 610_C, and 610_D each include setting items F1 to F8. Therefore, background images 610_A, 610_B, 610_C, and 610_D each include eight setting item images representing setting items F1 to F8. That is, background image 610_A includes eight setting item images 611_A to 618_A representing setting items F1 to F8, and setting item images 611_A to 618_A correspond to setting items 611 to 618 in FIG. 7, respectively. Background image 610_B includes eight setting item images 611_B to 618_B representing setting items F1 to F8, and setting item images 611_B to 618_B correspond to setting items 611 to 618 in FIG. 7, respectively. Background image 610_C includes eight setting item images 611_C to 618_C representing setting items F1 to F8, and setting item images 611_C to 618_C respectively correspond to setting items 611 to 618 in Fig. 7. Background image 610_D includes eight setting item images 611_D to 618_D representing setting items F1 to F8, and setting item images 611_D to 618_D respectively correspond to setting items 611 to 618 in Fig. 7.

[0055] The background images 610_A, 610_B, 610_C, and 610_D are rectangular images, and the horizontal lengths of the background images 610_A, 610_B, 610_C, and 610_D are respectively represented by the symbol “L F_A ", "L F_B " , "L F_C " , "L F_D "See "L F_A <L F_B <L F_C <L F_D " holds true.

[0056] The horizontal length of each setting item image (611_A, etc.) included in the background image 610_A is length L F_A and the horizontal length of each setting item image (611_B, etc.) included in the background image 610_B is length L F_B and the horizontal length of each setting item image (611_C, etc.) included in the background image 610_C is length L F_Cand the horizontal length of each setting item image (611_D, etc.) included in the background image 610_D is length L F_D shall be deemed to be consistent with

[0057] In the second embodiment, the horizontal length of the menu image displayed by the OSD function is represented by the symbol "L F2 " The length L F2 is also the horizontal length of each setting item (F1 to F8) displayed in the menu image. F2 is the length L F_A , L F_B , L F_C and L F_D It is believed to be either of the following.

[0058] When compositing a menu image including any of OSD images 610_A to 610_D as a background image with an input image, the video IC 20 dynamically sets the length of the cursor CSR2 to be superimposed on the background image according to the horizontal length of the background image to be composited (and therefore according to the horizontal length of each setting item in the background image to be composited).

[0059] FIG. 17(a) shows a composite image 810_A displayed on the display screen 32 when an arbitrary input image and a menu image including an OSD image 610_A as a background image are composited by the OSD function. FIG. 17(b) shows a composite image 810_B displayed on the display screen 32 when an arbitrary input image and a menu image including an OSD image 610_B as a background image are composited by the OSD function. FIG. 18(a) shows a composite image 810_C displayed on the display screen 32 when an arbitrary input image and a menu image including an OSD image 610_C as a background image are composited by the OSD function. FIG. 18(b) shows a composite image 810_D displayed on the display screen 32 when an arbitrary input image and a menu image including an OSD image 610_D as a background image are composited by the OSD function.

[0060] When the video IC 20 synthesizes a menu image including an OSD image 610_A as a background image with an input image, the video IC 20 forms a menu image using a cursor CSR2_1 as the cursor CSR2. When the video IC 20 synthesizes a menu image including an OSD image 610_B as a background image with an input image, the video IC 20 forms a menu image using a cursor CSR2_2 as the cursor CSR2. When the video IC 20 synthesizes a menu image including an OSD image 610_C as a background image with an input image, the video IC 20 forms a menu image using a cursor CSR2_3 as the cursor CSR2. When the video IC 20 synthesizes a menu image including an OSD image 610_D as a background image with an input image, the video IC 20 also forms a menu image using a cursor CSR2_3 as the cursor CSR2. The video IC 20 generates a synthetic image by synthesizing the formed menu image with the input image. Therefore, the cursors CSR2 in the composite images 810_A and 810_B are cursors CSR2_1 and CSR2_2, respectively, and the cursors CSR2 in the composite images 810_C and 810_D are both cursors CSR2_3.

[0061] 17(a) and (b) and 18(a) and (b), it is assumed that the setting item F3 is selected. Therefore, in the composite image 810_A, a cursor CSR2_1 is superimposed on the setting item image 613_A corresponding to the setting item F3. Similarly, in the composite image 810_B, a cursor CSR2_2 is superimposed on the setting item image 613_B corresponding to the setting item F3. Similarly, in the composite image 810_C, a cursor CSR2_3 is superimposed on the setting item image 613_C corresponding to the setting item F3. Similarly, in the composite image 810_D, a cursor CSR2_3 is superimposed on the setting item image 613_D corresponding to the setting item F3.

[0062] In the second embodiment, as in the first embodiment, the length L of the cursor CSR2 CSR2 In the second embodiment, the length L CSR2 is the predetermined upper limit L LIM2 The limit is set so as not to exceed “L CSR2 ≦L LIM2", the synthesis in the buffer memory 21 is completed in time, and no distortion occurs in the image on the display screen 32 (such that the upper limit value L LIM2 The length L of the cursor CSR2_3 in Figure 15(c) is CSR2_L is the upper limit L LIM2 The upper limit L LIM2 is the upper limit L mentioned in the first embodiment. LIM1 It may be understood to be the same as (but may be different from) the upper limit L LIM2 The length indicated by is shorter than the entire horizontal length of the display screen 32 (the length of 1920 pixels).

[0063] In the second embodiment, the length of the cursor CSR2 is varied within a range where no distortion occurs in the image. F_A , L F_B , L F_C and L F_D is the horizontal length of the menu image L F2 (The length of the setting items F1 to F8) corresponds to the candidates. LIM2 Between F_A <L F_B <L F_C =L LIM2 <L F_D " or "L F_A <L F_B <L F_C <L LIM2 <L F_D " holds true.

[0064] Length L F2 is the upper limit L LIM2 When the length L of the cursor CSR2 is less than or equal to the length L of the cursor CSR2, the image IC 20 CSR2 Length L F2 That is, "L F2 ≦L LIM2 If " is true, then the length L F2 As the length L increases CSR2 Increase the length L F2 As the length L decreases CSR2 In Fig. 17(a), Fig. 17(b) and Fig. 18(a), the length L F2 is the length L F_A , L F_Band L F_C The length of cursor CSR2 changes in conjunction with L CSR2 is the length L CSR2_S , L CSR2_M and L CSR2_L (See also Figures 15(a)-(c)).

[0065] In contrast, the length L F2 is the upper limit L LIM2 When the length of the cursor CSR2 exceeds L CSR2 Length L F2 Without following the length L CSR2 The upper limit L LIM2 The following restrictions apply: CSR2 =L LIM2 In FIG. 18(b), “L LIM2 <L F2 =L F_D " and the upper limit L LIM2 A cursor CSR2_3 with the following length is displayed:

[0066] The second embodiment also imposes an appropriate limit on the length of the cursor, so that it is possible to avoid the image being distorted due to the composition not being completed in time. In addition, as long as the length of the cursor does not exceed the upper limit, the length of the cursor can be changed in conjunction with the horizontal length of each setting item, so that it is possible to display an OSD image with a high degree of freedom (high degree of freedom because there is no limit on the length) that prioritizes appearance, etc. In other words, it is possible to suppress image display distortion while also achieving design and ease of viewing.

[0067] Although three lengths are given as the types of horizontal lengths that the cursor CSR2 can have, the types of horizontal lengths that the cursor CSR2 can have may be two, or may be four or more.

[0068] Also, the length of the cursor CSR is limited to the upper limit L CSR2 If the length is less than or equal to the length L, the image will not be distorted even if the shape of the cursor CSR2 is not a line. F2 is the upper limit L LIM2If the length L is less than the length L, the shape of the cursor CSR2 may be changed to the shape of a frame surrounding the setting item. F2 is the upper limit L LIM2 When it exceeds the limit, the shape of cursor CSR2 is treated as a line segment and the length L of cursor CSR2 is CSR2 The upper limit L LIM2 It is sufficient to limit the length to the following: F2 is the upper limit L LIM2 When the cursor CSR2 exceeds the , it functions as an underline for the selected setting item.

[0069] This transformation method will be explained. Figures 19(a) and (b) and Figures 20(a) and (b) show composite images 810_A', 810_B', 810_C', and 810_D' that can be displayed by this transformation method. The composite image 810_A' is a composite image displayed on the display screen 32 when an arbitrary input image and a menu image including the OSD image 610_A as a background image are synthesized by the OSD function. The composite image 810_B' is a composite image displayed on the display screen 32 when an arbitrary input image and a menu image including the OSD image 610_B as a background image are synthesized by the OSD function. The composite image 810_C' is a composite image displayed on the display screen 32 when an arbitrary input image and a menu image including the OSD image 610_C as a background image are synthesized by the OSD function. The composite image 810_D' is a composite image that is displayed on the display screen 32 when an arbitrary input image and a menu image including the OSD image 610_D as a background image are composited by the OSD function.

[0070] A composite image 810_A' is obtained by simply replacing the cursor CSR2_1 with a cursor CSR2_1' based on the composite image 810_A in FIG. 17(a). A composite image 810_B' is obtained by simply replacing the cursor CSR2_2 with a cursor CSR2_2' based on the composite image 810_B in FIG. 17(b). A composite image 810_C' is obtained by simply replacing the cursor CSR2_3 with a cursor CSR2_3' based on the composite image 810_C in FIG. 18(a). A composite image 810_D' is the same as the composite image 810_D in FIG. 18(b).

[0071] That is, when the OSD images 610_A, 610_B, 610_C, and 610_D are used as background images, the video IC 20 according to the transformation method forms a menu image using the cursors CSR2_1', CSR2_2', CSR2_3', and CSR2_3 as the cursor CSR2, respectively. The video IC 20 generates a composite image by combining the formed menu image with an input image.

[0072] 19(a) and (b) and 20(a) and (b), it is assumed that the setting item F3 is selected. Therefore, in a composite image 810_A', a cursor CSR2_1' is superimposed on the setting item image 613_A corresponding to the setting item F3. Similarly, in a composite image 810_B', a cursor CSR2_2' is superimposed on the setting item image 613_B corresponding to the setting item F3. Similarly, in a composite image 810_C', a cursor CSR2_3' is superimposed on the setting item image 613_C corresponding to the setting item F3. Similarly, in a composite image 810_D', a cursor CSR2_3 is superimposed on the setting item image 613_D corresponding to the setting item F3.

[0073] The cursors CSR2_1', CSR2_2', and CSR2_3' in the composite images 810_A', 810_B', and 810_C' respectively have the shape of a surrounding frame for the selected setting item F3. The surrounding frame for the setting item F3 refers to a frame that surrounds all the components of the setting item F3 on all four sides. The surrounding frame may be a rectangular frame or a frame that includes curves.

[0074] FIG. 21 shows the relationship between the cursor CSR2_2' and the setting item F3 when it is assumed that the OSD image 610_B coincides with the OSD image 610 shown in FIG. 7. The setting item F3 in FIG. 21 is composed of the characters "contrast", "weak", and "strong", and a linear pattern placed between the characters "weak" and "strong". In FIG. 21, the cursor CSR2_2' is a frame that surrounds all the components of the setting item F3 (the characters "contrast", "weak", and "strong", and the linear pattern placed between the characters "weak" and "strong") on all four sides. Although an example when the setting item F3 is selected is given, the same applies when other setting items are selected.

[0075] As mentioned above, “L F_A <L F_B <L F_C =L LIM2 <L F_D " or "L F_A <L F_B <L F_C <L LIM2 <L F_D " is satisfied, the lengths of the cursors CSR2_1', CSR2_2', and CSR2_3' in the horizontal direction are all within the upper limit L LIM2 The lengths of the cursors CSR2_1', CSR2_2', and CSR2_3' in the horizontal direction are different from one another. Among those lengths, the length of the cursor CSR2_1' in the horizontal direction is the smallest, and the length of the cursor CSR2_3' in the horizontal direction is the largest.

[0076] The transformation method shown in Fig. 19(a) also places an appropriate limit on the length of the cursor, so it is possible to avoid the image being distorted due to composition not being completed in time. Also, as long as the length of the cursor does not exceed the upper limit, the shape of the cursor can be made into a frame, so that appearance can be prioritized. In other words, it is possible to suppress image display distortion while also achieving design and ease of viewing.

[0077] <<Third Example>> A third embodiment will be described. As described above, when the OSD function is used, the video IC 20 generates a display image on the display screen 32 by superimposing one or more OSD images on the input image. At this time, two or more OSD images may be superimposed on the same horizontal scanning line. In this case, the longer the total length of each OSD image superimposed on the same horizontal scanning line, the more likely it is that image distortion will occur as the synthesis takes longer.

[0078] Taking this into consideration, the video IC 20 according to the third embodiment is configured such that, when multiple OSD images are displayed in a superimposed manner on the same horizontal scanning line, the total length of the multiple OSD images on the same horizontal scanning line does not exceed a predetermined upper limit value SUM LIM A display image is generated so that the

[0079] This also prevents the image from being distorted due to the composition not being completed in time.

[0080] A specific example will be described. A case where a menu image including the cursor CSR1 in FIG. 12 and the background image 610 in FIG. 13 as two OSD images is synthesized with an input image by the OSD function is called the first case. The cursor CSR1 is an example of the OSD image 680 shown in FIG. 8. In the first case, the input image is arranged in the third layer, the background image 610 is arranged in the second layer, and the cursor CSR1 is arranged in the first layer. Then, for example, as shown in FIG. 22, the cursor CSR1 is superimposed on the setting item image 613 in the background image 610.

[0081] 22, a dashed line 920 indicates a horizontal scanning line belonging to the display area of ​​the cursor CSR1. That is, image information AA of the input image on the horizontal scanning line 920, image information BB of the background image 610 on the horizontal scanning line 920, and image information BB of the cursor CSR1 on the horizontal scanning line 920 are synthesized using the buffer memory 21, thereby generating a video signal CC for the horizontal scanning line 920.

[0082] At this time, the total length of the OSD image on the horizontal scanning line 920 is set to an upper limit value SUM LIMIn the first case, the OSD image on the horizontal scanning line 920 is composed of the first OSD image as the background image 610 and the second OSD image (680) as the cursor CSR1. Therefore, in the first case, the total length of the OSD image on the horizontal scanning line 920 is the length L CSR1 and L F1 The sum of (L CSR1 +L F1 ) (see FIG. 12 and FIG. 13). The image IC 20 according to the first case is “L CSR1 +L F1 ≦SUM LIM The display image is generated so that “L CSR1 +L F1 ≦SUM LIM The horizontal length of each OSD image may be set so that " is satisfied.

[0083] Furthermore, with reference to Fig. 23, the following second case will be considered. In the second case, a menu image including a cursor CSR1 (680), a background image 610, and a marker 632 as three OSD images is synthesized with an input image by the OSD function. The marker 632 corresponds to the example of the OSD image 630 shown in Fig. 8. In the second case, the input image is arranged in the third layer, the background image 610 is arranged in the second layer, and the cursor CSR1 and the marker 632 are arranged in the first layer. Then, for example, the cursor CSR1 and the marker 632 are superimposed at different positions on the setting item image 613 in the background image 610.

[0084] 23, the cursor CSR1, the background image 610, and the marker 632 are positioned on a horizontal scanning line 920. That is, image information AA of the input image on the horizontal scanning line 920, image information BB of the background image 610 on the horizontal scanning line 920, image information BB of the cursor CSR1 on the horizontal scanning line 920, and image information BB of the marker 632 on the horizontal scanning line 920 are synthesized using the buffer memory 21, thereby generating a video signal CC for the horizontal scanning line 920.

[0085] At this time, the total length of the OSD image on the horizontal scanning line 920 is set to an upper limit value SUM LIM In the second case, the OSD images on the horizontal scan line 920 are composed of the first OSD image as the background image 610, the second OSD image (680) as the cursor CSR1, and the third OSD image as the marker 632. Therefore, in the second case, the total length of the OSD images on the horizontal scan line 920 is the sum (L CSR1 +L F1 +L 632 ) (see Figures 12 and 13). Here, L 632 represents the horizontal length of the marker 632 on the horizontal scanning line 920. CSR1 +L F1 +L 632 ≦SUM LIM The display image is generated so that “L CSR1 +L F1 +L 632 ≦SUM LIM The horizontal length of each OSD image may be set so that " is satisfied.

[0086] The first case is an example in which two OSD images are superimposed on the same horizontal scanning line 920, and the second case is an example in which three OSD images are superimposed on the same horizontal scanning line 920, but the number of OSD images superimposed on the same horizontal scanning line 920 can be four or more. Note that in the example of Fig. 23, three or more OSD images are not superimposed at the same display position, but three or more OSD images may be superimposed at the same display position.

[0087] In addition, an increase in the number of layers during synthesis leads to an increase in synthesis processing time. Therefore, as the number of layers of multiple OSD images superimposed on the same horizontal scanning line 920 increases, the upper limit value SUM LIM may be made smaller.

[0088] This allows the horizontal length of each OSD image to be appropriately set, taking into consideration the increased load of synthesis processing that accompanies an increase in the number of layers. As a result, it is possible to prevent the image from being distorted due to synthesis not being completed in time. LIM It can be thought of as lowering

[0089] A third case is assumed in which OSD images 941 and 942 are composited with an input image 940 (see FIG. 24(a)). In the third case, the OSD images 941, 942, and the input image 940 are arranged on the first, second, and third layers, respectively. In the third case, it is assumed that the OSD images 941 and 942 are arranged on the same horizontal scanning line 920. A fourth case is assumed in which OSD images 961 to 963 are composited with an input image 960 (see FIG. 24(b)). In the fourth case, the OSD images 961, 962, 963, and the input image 960 are arranged on the first, second, third, and fourth layers, respectively. In the fourth case, it is assumed that the OSD images 961 to 963 are arranged on the same horizontal scanning line 920.

[0090] In the third case, the number of layers of multiple OSD images superimposed on the same horizontal scanning line 920 (the total number of layers of arrangement of OSD images 941 and 942 superimposed on the same horizontal scanning line 920) is "2". In contrast, in the fourth case, the number of layers of multiple OSD images superimposed on the same horizontal scanning line 920 (the total number of layers of arrangement of OSD images 961 to 963 superimposed on the same horizontal scanning line 920) is "3". Therefore, the upper limit value SUM LIM Compared with the upper limit SUM in the fourth case LIM It is better to make it smaller.

[0091] For the sake of simplicity, attention has been focused on one horizontal scan line 920, but the method according to the present embodiment can be applied to each horizontal scan line.

[0092] <<Fourth Example>> A fourth embodiment will now be described. Consider displaying an OSD image expressing specific content on the display screen 32. Here, it is assumed that the display device 1 is installed in a vehicle such as an automobile, and the OSD image expressing specific content is the OSD image 1120 in Fig. 25 as an example. The OSD image 1120 is an image that informs the passengers that they should fasten their seat belts for safety.

[0093] The OSD image 1120 is composed of an image area 1121 having a predetermined background color (e.g., black), an image area 1122 in which a text image is displayed, and an image area 1123 showing an image of a person fastening a seat belt. The image area 1121 is a flat image portion filled with a predetermined background color, and the text areas 1122 and 1123 are arranged inside the image area 1121 in a manner that they are surrounded by the image area 1121.

[0094] Although it differs from reality, if the vertical and horizontal lengths of the OSD image 1120 were made to match those of the display screen 32, there would be no particular concern about the appearance. However, as described above, it is difficult to unlimitedly increase the horizontal length of the OSD image 1120 from the viewpoint of suppressing image distortion. Therefore, for example, the horizontal length of the OSD image 1120 is set to a predetermined value (for example, the upper limit value L mentioned in the first embodiment) that is smaller than the total horizontal length of the display screen 32. LIM1 ) is limited to the following:

[0095] When the horizontal length of the OSD image 1120 is limited to a predetermined value or less, when the OSD image 1120 is displayed on the display screen 32, the entire display area of ​​the display screen 32 will include a display area in which the OSD image 1120 is displayed and a display area in which the OSD image 1120 is not displayed. When an input image is displayed in the latter display area, the appearance may not be satisfactory.

[0096] Considering this, when the OSD image 1120 is displayed on the display screen 32, the video IC 20 combines an image that it holds in advance (hereinafter referred to as an IC-held image) with the OSD image 1120, instead of the input image supplied from the input image supply unit 10. The video IC 20 has a built-in non-volatile memory (not shown), and one or more IC-held images are stored in the built-in non-volatile memory of the video IC 20. The IC-held images are, for example, a mute image, which is a flat monochromatic image, and a test pattern image.

[0097] 26 shows how the mute image 1140 and the OSD image 1120 are composited in the video IC 20 by the OSD function. At this time, a composite image 1160 equivalent to an image in which the OSD image 1120 is superimposed at a predetermined position on the mute image 1140 is generated, and the composite image 1160 is displayed on the display screen 32. The color of the mute image 1140 is the same as or substantially the same as (belonging to a similar color family) the background color of the OSD image 1120 (the color of the image area 1121: see FIG. 25). Therefore, the image display does not look unnatural, and the above-mentioned concerns about appearance are resolved.

[0098] Incidentally, an IC holding image other than the mute image 1140 (for example, a test pattern image having seven colors) may be composited with the OSD image 1120, and the composite image may be displayed on the display screen 32.

[0099] <<Fifth Example>> A fifth embodiment will be described. The video IC 20 may have an OSD memory (not shown) that holds several OSD images. The OSD memory here is a non-volatile memory separate from the memory 40. The OSD memory in the video IC 20 is mainly used to hold OSD images that represent characters. For this reason, hereinafter, the OSD memory in the video IC 20 will be referred to as a font OSD memory.

[0100] It is assumed that the font OSD memory holds font images 1320 to 1329 shown in Fig. 27 as OSD images (i.e., image information of the font images 1320 to 1329 is stored). The font images 1320 to 1329 are images representing the numbers "0" to "9", respectively.

[0101] On the other hand, it is assumed that the memory 40 stores an OSD image 1360 shown in FIG. 28. The OSD image 1360 is an OSD image that is assumed to be used in combination with some of the font images 1320 to 1329. The horizontal length of the OSD image 1360 is a predetermined value (for example, the upper limit value L described in the first embodiment) that is smaller than the total horizontal length of the display screen 32. LIM1 28, the OSD image 1360 may include one or more setting items such as the above-mentioned setting items F1 to F8. The horizontal length of each of the font images 1320 to 1329 is sufficiently shorter than the horizontal length of the OSD image 1360.

[0102] The video IC 20 can generate a composite image 1380 shown in FIG. 29 under the control of the control unit 50, for example, and display it on the display screen 32. The composite image 1380 is an image obtained by combining the mute image 1140, the OSD image 1360, and some of the font images 1320 to 1329. In the example of FIG. 29, the mute image 1140 is arranged on the third layer, the OSD image 1360 is arranged on the second layer, and the font images 1323, 1320, and 1322 are arranged on the first layer. As a result, on the display screen 32, the OSD image 1360 is displayed superimposed at a predetermined position on the mute image 1140, and the font images 1323, 1320, and 1322 are displayed superimposed at predetermined positions on the OSD image 1360. At this time, the font images 1323, 1320, and 1322 are displayed side by side in the horizontal direction.

[0103] The combination of font images arranged and displayed in composite image 1380 represents, for example, version information of display device 1 or a device including display device 1. The version information is updated, for example, in conjunction with an update of the version of a program executed by the CPU in control unit 50. The version information is represented by multiple characters arranged horizontally (in the example of FIG. 29, the characters "3", "0", and "2"). If an OSD image of the multiple characters were to be read out from memory 40, there is a risk that the composition would not be completed in time due to the communication speed between video IC 20 and memory 40.

[0104] The communication speed of the font OSD memory, which corresponds to the internal memory of the video IC 20, is faster than the communication speed of the memory 40, which corresponds to the external memory of the video IC 20. By displaying version information using the font OSD memory, restrictions on communication speed are reduced, and image distortion can be easily avoided even when multiple font images are arranged horizontally using the OSD function.

[0105] <<Sixth Example>> A sixth embodiment will now be described.

[0106] The display device 1 can be installed in a vehicle such as an automobile. The display device 1 may be incorporated in any device (on-board device) mounted in a vehicle. For example, the display device 1 may be incorporated in an on-board device that constitutes a car navigation system.

[0107] However, the display device 1 is not limited to in-vehicle applications and may be used in any type of display device. That is, the display device 1 may be mounted on any device that requires a display device, such as a personal computer, an information terminal (e.g., a tablet or a smartphone), a game device, or a television receiver.

[0108] The embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims. The above embodiments are merely examples of the present invention, and the meanings of the terms of the present invention and each component are not limited to those described in the above embodiments. The specific numerical values ​​shown in the above description are merely examples, and can be changed to various numerical values ​​as a matter of course. [Explanation of symbols]

[0109] 1 Display device 10 Input image supply unit 20 Video IC 21 Buffer Memory 30 Display section 31 Drivers 32 Display screen 40 Memory 50 Control section 60 Control section 61 Up button 62 Down button 63 Left Button 64 Right Button

Claims

1. A display screen; a signal processing unit that displays an item on the display screen and displays a cursor indicating that the item is selected in a superimposed manner on the item; an input image supply unit that supplies an input image to the signal processing unit; a memory for storing two or more OSD images including a first OSD image representing the item and a second OSD image representing the cursor; the signal processing unit generates a display image for the display screen by superimposing an OSD image read from the memory on the input image by an on-screen display, and displays the cursor such that a ratio of a length of the cursor to a length of the item in a horizontal scanning line direction of the display screen does not exceed a predetermined ratio; The signal processing unit generates the display image such that, when a plurality of OSD images are superimposed on the same horizontal scanning line, a total length of the plurality of OSD images on the same horizontal scanning line does not exceed a predetermined value. , display device.

2. As the number of layers of the OSD images superimposed on the same horizontal scanning line increases, the predetermined value decreases. The display device according to claim 1 .

3. 1. A display control method for displaying an item on a display screen and superimposing a cursor on the item to indicate that the item is selected, comprising: a first OSD image representing the item and a second OSD image representing the cursor are read from a memory, and the read OSD images are superimposed on an input image by an on-screen display to generate a display image for the display screen; the cursor is displayed such that a ratio of a length of the cursor to a length of the item in a horizontal scanning line direction of the display screen does not exceed a predetermined ratio; and when a plurality of OSD images are superimposed on the same horizontal scanning line, the display image is generated such that a total length of the plurality of OSD images on the same horizontal scanning line does not exceed a predetermined value. , display control method.

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