JPH09204153A - Electron-beam display and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct the decrease in luminance resulting from the position relation between a user and a large-screen display by providing a correcting means which measures the position relation between plural places of an image display part and the user and varies the luminance at the places according to the position relation. SOLUTION: This display consists of the image display part 1, an observation position detection part 2 which measures the observation position P of the user, and a display image processing part 3 which processes an image signal according to the observation position P of the user and outputs the result to the image display part 1, and the user holds the observation position detection part 2 in this case. In this constitution, the position relation between >=2 places of the image display part 1 and the observation position detection part 2 where the user is measured to correct the luminance at the respective places of the image display part 1. In this case, the coordinates of the observation position P of the user is obtained first and a correction quantity for a display image corresponding to the position P is calculated. Light distribution characteristics of a display surface are already obtained, so observation angles Θregarding respective display elements are found and the correction quantity is calculated from the characteristic values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam display which corrects optical characteristics such as a decrease in observation brightness caused by a positional relationship between an image display section and a user, which occurs daily, and a driving method thereof.

[0002]

2. Description of the Related Art Conventionally, as a technique in the field of electron beam displays, there are few proposals relating to brightness correction for the following reasons. 1) A CRT is considered to be close to a uniform diffusion surface light source.
Therefore, it is considered that the brightness is constant regardless of the direction of the CRT. 2) Since the display device is small, the observation angle of the user is almost constant, and it is not necessary to consider the light distribution characteristic of the display device as a problem. (Observation angle means the angle between the normal line at a point on the display surface and the line of sight of the user who sees that point)

However, now that various large screen displays have been developed, the above problems cannot be avoided in order to provide a better image to the user. FIG. 9 is a diagram showing this problem in an easy-to-understand manner, where the user is observing the positions A and B of the large screen display device (arrows are normals to the display surface). Conventionally, since the display device was small,
Since the observation angle at the position A and the observation angle at the position B are almost equal to each other, there is little problem. However, when observing an image on a large-screen display device today, the angles are greatly different as shown.

On the other hand, attention has been paid to a liquid crystal display because the viewing angle dependence of contrast is large.
Some Japanese Patent Application Laid-Open No. 5-232906 changes the brightness on the assumption that the observation angle in the screen changes.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and when an image is displayed on an electron beam display, a display inevitably generated due to the positional relationship between the user and the large screen display. The purpose of the present invention is to correct display information, for example, a decrease in brightness, according to the light distribution characteristics of the device.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention earnestly made efforts to obtain the following invention. That is, the electron beam display of the present invention is an electron beam display having an image display unit and a correction unit capable of correcting the brightness, wherein the correction unit measures a positional relationship between two or more positions of the image display unit and a user. The brightness of the location can be changed from the positional relationship.
At this time, the light distribution characteristic of the display surface of the image display unit may be used as the image correction amount.

The present invention also includes the invention of a driving method for an electron beam display. That is, the invention of the driving method for the electron beam display according to the present invention is to detect the positional relationship between the user and two or more positions of the image display unit, to calculate an image correction amount according to the positional relationship, The method is characterized by including the step of correcting the image signal according to the location based on the correction amount and the step of displaying the corrected image signal on the image display unit. At this time, the light distribution characteristic of the display surface may be used as the image correction amount for the image display unit.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view best showing the features of the present invention, (a) is a block diagram of a display method, and (b) is a perspective view of the entire system. In the figure, reference numeral 1 denotes an image display unit for displaying an image, which is a display device that can use an electron beam display. Reference numeral 2 is an observation position detection unit that measures the observation position of the user, and reference numeral 3 is a display image processing unit that processes an image signal according to the observation position of the user and outputs the image signal to the image display unit 1. FIG. 1 (b) illustrates the usage state of the present invention in an easy-to-understand manner. In this case, the user holds the observation position detection unit.

The brightness observed through the face glass of a flat electron beam display is different from that of a cathode ray tube screen which is considered to be close to a uniform diffusion surface.
Generally, there is an angle dependency as shown in FIG. The luminance Lv (θ) at the observation angle θ is the luminance in the normal direction Lvo
Then, it can be approximated by the following equation.

Lv (θ) = Lvo · cos ^0.4 θ (Equation 1) FIG. 3A is a flowchart showing the operation steps of the present invention. The operation of FIG. 3A will be described below with reference to FIG. First, when the device starts operating (step 3-1), it is determined whether or not the observation position of the user needs to be updated. If it is judged necessary,
Perform step 3-2. (Step 3-2) The observation position of the user is measured. For the sake of explanation, the lower left corner of the display surface as the coordinate origin is set as shown in FIG. 1B, and the coordinate system is set as shown. In this step, the coordinates (Xp, Yp, Zp) of the observation position P are obtained. (Step 3-3) In this step, the correction amount of the display image according to the observation position is calculated. Since the light distribution characteristic of the display surface is obtained in advance, the observation angle θ regarding each display pixel is obtained, and the correction amount is calculated from the characteristic value. (Step 3-4) In this step, the display image is processed based on the correction amount. FIG. 3B shows the case of the brightness correction illustrated in (Equation 1) and FIG. 2. Details will be described later.

(Step 3-5) In this step, the image corrected in step 3-3 is displayed on the display device. Then, if it is necessary to continue, the control is transferred to step 3-1.

FIG. 3B shows the details of step 3-3 in the case where the light distribution characteristic is exemplified in (Equation 1) and FIG.
Moreover, the case where the brightness value of each pixel is corrected is shown. (Step 4-1) Display pixels in the horizontal direction are i = 1 to Nx.
It is assumed that there are j = 1 to Ny pixels in the vertical direction. In this step, one pixel among them, for example, the pixel at the position (1, 1) is set as the initial pixel of interest. (Step 4-2) Coordinates Q (Xq, Yq, Zq) on the display surface of the pixel of interest (i, j) and observation position coordinates P (Xp,
The observation angle θ is calculated from Yp, Zp). (Step 4-3) The relative luminance value Lv (θ) is calculated from the angle of interest θ using (Equation 1). (Step 4-4) 1 / Lv of the luminance data of the pixel of interest
(Θ) times. (Step 4-5) If the pixel of interest is (Nx, Ny), the process ends. If not, control is transferred to (step 4-6). (Step 4-6) The pixel of interest (i, j) is moved to the next unprocessed pixel. For example, if i is not equal to Nx, increase i by 1. If i is equal to Nx, increase j by 1 and let i be 1. After this, (Step 4-
Transfer control to 2).

The following cases can be considered as modifications of the present invention. -Acceleration of calculation In the case described above, since the correction amount is calculated for each pixel, it takes time to process. In order to speed up this, it is possible to save the calculated correction amount as a table. FIG. 4 is a flowchart for measuring this speedup. -When fixing the user position Depending on the display application, the user position may be fixed. In such a case, the user position detection unit and its stage are unnecessary. -When there are multiple users but the observation positions are relatively concentrated In such a case, the above example can be applied by calculating the average value of the observation positions and using this as the user position. . In the case of correcting the color information In this embodiment, the luminance information is mainly the correction target. In order to extend this to color information, the light distribution characteristic for each color of the display surface is used and correction processing corresponding to the color is performed. -When using another correction method In this embodiment, a correction method for increasing the brightness of a pixel whose brightness is reduced is introduced. However, if human visual characteristics are applied, it is possible to obtain a considerable effect, for example, by changing the contrast.

Next, a specific structure of the image display unit 1 will be described. FIG. 5 is a perspective view of a display panel of an electron beam flat display using a surface conduction electron-emitting device, which is a thin and large display, which is being researched and developed by the applicant. The figure cuts out a part of the panel to show the internal structure. In the figure, 31 is a substrate, 32 is a surface conduction electron-emitting device, 33 is a row wiring, 34 is a column wiring, 35 is a rear plate, 36 is a side wall, 37 is a face plate, 3
Reference numeral 8 is a fluorescent film, and 39 is a metal back. The rear plate 35, the side wall 36, and the face plate 37 form an airtight container, and maintain the inside of the display in a vacuum. The face plate 37 fixes the fluorescent film 38 and the metal back 39. The metal back 39 serves to specularly reflect a part of the light emitted by the fluorescent film 38 to improve the light utilization rate and to protect the fluorescent film 58 from the collision of negative ions. Further, the metal back 39 serves as an electrode for accelerating electrons and a conduction path for electrons that excite the fluorescent film. The rear plate 35 is
The substrate 31, the surface conduction electron-emitting device 32, the row wiring 33, and the column wiring 34 are fixed. Dx1 to Dxm, Dy1 to Dyn,
Hv is the inner row wiring 33, the column wiring 34, and the metal back 39 while maintaining the airtight structure of the display.
And an external drive circuit. A bright, thin, and large display can be provided by arranging one surface conduction electron-emitting device 32 as an electron source for each pixel.

FIG. 6 shows a drive circuit of the display panel of FIG. In the figure, 41 is a display panel, 42 is a scanning circuit, 43 is a decoder, 44 is a timing generation circuit, 45 is a sampling hold (S / H) circuit, 46 is a serial-parallel (S / P) conversion circuit, and 47 is a pulse width. It is a modulation circuit.
The decoder 43 uses the image signals to output the R, G, and B luminance signals, the horizontal synchronization signal (SHYNC), and the vertical synchronization signal (VSYNC).
C) and separate. Here, the image signal is subjected to the brightness correction according to the position of the present invention. Timing generation circuit 4
4 is a horizontal synchronization signal (HSYNC) and a vertical synchronization signal (V
SYNC) to control signal (Tscan) of the scanning circuit 42
And a control signal for the S / H circuit 45. S / H circuit 4
Reference numeral 5 samples and holds the R, G, and B luminance signals at the timing of the control signal. The S / P conversion circuit 46
The output signal of the H circuit 45 is converted into a parallel signal having a pulse width of one horizontal period (1H) so that it can be driven in line-sequential order. The pulse width modulation circuit 47 modulates the output signal of the S / P conversion circuit 46 into a pulse width signal and outputs it to the terminals Dy1 to Dyn of the column wiring of the display panel. The scanning circuit 42 sequentially outputs selection signals to the terminals Dx1 to Dxm of the row wiring.

[0016]

As described above, according to the present invention,
Display information, for example, a decrease in brightness caused by the light distribution characteristic of the display surface is corrected in consideration of the observation position, so that the image is improved.

[Brief description of drawings]

FIG. 1 is a diagram best representing the features of the present invention.

FIG. 2 is a diagram showing relative luminance according to an observation angle.

FIG. 3 is a flowchart illustrating the operation of the present invention.

FIG. 4 is a flowchart for explaining the operation of the modification of the present invention.

FIG. 5 is a perspective view of a display panel using a surface conduction electron-emitting device.

FIG. 6 is a block diagram of a drive circuit of a display panel.

FIG. 7 is a diagram illustrating a problem

[Explanation of symbols]

 1 Display 2 Observation Position Detector 3 Display Image Processor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidetoshi Haru 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. An electron beam display having an image display section and a correction means capable of correcting brightness, wherein the correction means measures a positional relationship between two or more locations of the image display section and a user, and An electron beam display characterized in that it is possible to change the brightness of the location. 2. The electron beam display according to claim 1, wherein a light distribution characteristic of a display surface of the image display unit is used as an image correction amount. 3. A step of detecting a positional relationship between a user and two or more locations on an image display unit, a step of calculating an image correction amount according to the positional relationship, and an image signal based on the image correction amount. A method for driving an electron beam display, comprising: a step of correcting according to a location; and a step of displaying the corrected image signal on an image display unit. 4. The driving method for an electron beam display according to claim 3, wherein a light distribution characteristic of a display surface of the image display unit is used as an image correction amount.