CN116243451A

CN116243451A - Focusing adjustment method and device

Info

Publication number: CN116243451A
Application number: CN202211690044.2A
Authority: CN
Inventors: 闻铭; 徐凯华; 郑增强
Original assignee: Wuhan Jingce Electronic Group Co Ltd; Wuhan Jingli Electronic Technology Co Ltd; Suzhou Hirose Opto Co Ltd
Current assignee: Wuhan Jingce Electronic Group Co Ltd; Wuhan Jingli Electronic Technology Co Ltd; Suzhou Hirose Opto Co Ltd
Priority date: 2022-12-27
Filing date: 2022-12-27
Publication date: 2023-06-09

Abstract

The invention provides a focusing adjustment method and a focusing adjustment device. The method comprises the following steps: acquiring a first image obtained by imaging a focusing test image displayed on a first display panel by using an LMD (least squares) device, wherein the focusing test image comprises a two-dimensional MTF test pattern and a face pattern; automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image; and adjusting the focusing ring of the LMD according to the face pattern, so that the LMD is in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible. According to the invention, the LMD can quickly reach a slight virtual focus state, so that a screen image which can accurately extract the brightness of each pixel of the screen is quickly obtained.

Description

Focusing adjustment method and device

Technical Field

The present invention relates to the field of display panels, and in particular, to a focusing adjustment method and device.

Background

Display panels represented by Liquid Crystal Displays (LCDs) and organic light emitting diode displays (OLEDs) are becoming increasingly popular in people's lives. However, the display panel has more process flows in the preparation process, and each step may introduce flaws and defects, which ultimately affect the yield of the display panel and increase the cost, so that the display panel needs to be photographed and detected by using an LMD (light measuring device, typically an industrial camera or an area array luminance colorimeter) in the production process.

Two typical objectives of using LMD to photograph a display panel are AOI detection and DeMura, both of which require accurate extraction of the brightness of each pixel of the screen based on the screen image captured by the LMD. Based on this, how to make the LMD obtain the screen image capable of accurately extracting the brightness of each pixel of the screen rapidly is a technical problem to be solved.

Disclosure of Invention

The invention mainly aims to provide a focusing adjustment method and device, which aim to solve the technical problem of how to enable an LMD to quickly obtain a screen image capable of accurately extracting the brightness of each pixel of a screen.

In a first aspect, the present invention provides a focus adjustment method, including:

acquiring a first image obtained by imaging a focusing test image displayed on a first display panel by using an LMD (least squares) device, wherein the focusing test image comprises a two-dimensional MTF test pattern and a face pattern;

automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image;

and adjusting the focusing ring of the LMD according to the face pattern, so that the LMD is in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible.

Optionally, after the step of automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image, the method further includes:

detecting whether automatic focusing is correct or not;

and if the automatic focusing is correct, executing the step of adjusting the focusing ring of the LMD.

Optionally, the step of detecting whether the autofocus is correct includes:

acquiring a new first image obtained by taking an image of a focusing test image displayed on a first display panel by an LMD (least squares) subjected to automatic focusing;

detecting whether the face pattern in the new first image is the face pattern shot when the LMD is in a clear focusing state;

if the face pattern in the new first image is the face pattern obtained by shooting when the LMD is in a clear focusing state, determining that the automatic focusing is correct;

if the face pattern in the new first image is not the face pattern shot when the LMD is in the clear focusing state, determining the automatic focusing error.

Optionally, after the step of detecting whether the autofocus is correct, the method further includes:

and if the automatic focusing is wrong, returning to the step of acquiring a first image obtained by taking the focusing test image displayed on the first display panel by the light measurement device LMD.

Optionally, the step of adjusting the focus ring of the LMD includes:

and responding to the adjustment operation to adjust the focusing ring of the LMD, and displaying an image obtained by real-time image capturing of the face pattern in the focusing test image by the LMD on the second display panel in the adjustment process.

Optionally, a plurality of the two-dimensional MTF test patterns and face patterns are displayed at a plurality of different positions on the first display panel.

Optionally, four corners and the center of the screen body on the first display panel are respectively provided with the two-dimensional MTF test pattern and the face pattern.

Optionally, the two-dimensional MTF test pattern has a plurality of spatial frequencies, and the two-dimensional MTF test pattern is obtained by intersecting a horizontal stripe pattern and a vertical stripe pattern having different spatial frequencies.

Optionally, the two-dimensional MTF test is low frequency, medium frequency and high frequency in order from center to edge.

In a second aspect, the present invention also provides a focus adjustment apparatus including:

the acquisition module is used for acquiring a first image obtained by imaging a focusing test image displayed on the first display panel by the light measurement device LMD, wherein the focusing test image comprises a two-dimensional MTF test pattern and a human face pattern;

the automatic focusing module is used for automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image;

and the adjusting module is used for adjusting the focusing ring of the LMD to enable the LMD to be in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible.

In the invention, a first image obtained by taking an image of a focusing test image displayed on a first display panel by using light measurement equipment LMD is obtained, wherein the focusing test image comprises a two-dimensional MTF test pattern and a human face pattern; automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image; and adjusting the focusing ring of the LMD according to the face pattern, so that the LMD is in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible. When AOI detection and DeMura are performed on the first display panel, the LMD needs to take an image of a screen body image on the first display panel in a slight virtual focus state in order to avoid or weaken moire. According to the invention, the LMD is automatically focused based on the two-dimensional MTF test pattern, and the focusing ring of the LMD is further adjusted under the condition that the automatic focusing of the LMD is completed, so that the LMD can quickly reach a slight virtual focus state, and a screen image capable of accurately extracting the brightness of each pixel on the first display panel is quickly obtained.

Drawings

FIG. 1 is a flowchart illustrating an embodiment of a focus adjustment method according to the present invention;

FIG. 2 is a schematic diagram of a two-dimensional MTF test pattern according to an embodiment of the focus adjustment method of the present invention;

FIG. 3 is a schematic diagram of a conventional one-dimensional MTF test pattern;

FIG. 4 is a schematic diagram of a face pattern according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a focus adjustment method according to an embodiment of the invention;

FIG. 6 is a graph showing an image sharpness evaluation function;

fig. 7a is a schematic diagram of a face pattern obtained by capturing an image with an LMD in a clear focusing state according to an embodiment of the focusing adjustment method of the present invention;

fig. 7b is a schematic diagram of a face pattern obtained by capturing an image of an LMD in a less-virtual focus state according to an embodiment of the present invention;

fig. 7c is a schematic diagram of a face pattern obtained by capturing an image of an LMD in a slightly virtual focus state according to an embodiment of the present invention;

fig. 7d is a schematic diagram of a face pattern obtained by capturing an image when the LMD is in an excessive virtual focus state in an embodiment of the focus adjustment method of the present invention;

fig. 8 is a schematic functional block diagram of an embodiment of a focusing adjustment device of the present invention.

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

In a first aspect, an embodiment of the present invention provides a focus adjustment method.

In an embodiment, referring to fig. 1, fig. 1 is a flowchart illustrating an embodiment of a focusing adjustment method according to the present invention. As shown in fig. 1, the focus adjustment method includes:

step S10, acquiring a first image obtained by imaging a focusing test image displayed on a first display panel by using light measurement equipment LMD, wherein the focusing test image comprises a two-dimensional MTF test pattern and a human face pattern;

in this embodiment, a focus test image is first displayed on a first display panel, and then the focus test image displayed on the first display panel is imaged by an optical measurement device LMD to obtain a first image, where the optical measurement device LMD is typically an industrial camera or an area array luminance colorimeter. Thus, the execution body of the embodiment can acquire the first image obtained by taking the image of the focusing test image displayed on the first display panel by the LMD. The focusing test image comprises a two-dimensional MTF test pattern and a human face pattern.

Referring to fig. 2, fig. 2 is a schematic diagram of a two-dimensional MTF test pattern according to an embodiment of the focus adjustment method of the present invention. The two-dimensional MTF test pattern has the following characteristics:

the two-dimensional MTF test pattern has a plurality of spatial frequencies, and the two-dimensional MTF test pattern is obtained by intersecting a horizontal and a vertical stripe pattern having different spatial frequencies.

In one embodiment, the two-dimensional MTF test pattern is obtained by intersecting a transverse conventional one-dimensional MTF test pattern and a longitudinal conventional one-dimensional MTF test pattern with different spatial frequencies, and referring to fig. 3, fig. 3 is a schematic diagram of a conventional one-dimensional MTF test pattern.

Further, in an embodiment, the two-dimensional MTF test is low frequency, medium frequency, and high frequency in order from center to edge.

A typical two-dimensional MTF test pattern is as follows:

the two-dimensional MTF test pattern is composed of a foreground region and a background region, the respective gray scale values in the regions remain unchanged, and typical gray scale values are 255 and 128 respectively. The background area and the foreground area have resolutions of 200×200 and 162×162 pixels, respectively, and are aligned in center. The foreground area is a rectangular wave pattern with axisymmetric centers, and low frequency (period 10), medium frequency (period 6, 4) and high frequency (period 2) are sequentially arranged from the center to the edge. The middle and low frequencies have 3 periods respectively, the high frequency has 4 periods, the duty ratio is 50%, and the center is a foreground square block of 16 multiplied by 16.

It should be noted that the above description is only typical of two-dimensional MTF test patterns, and there may be other ways to adjust gray-scale values, cycle numbers, spatial frequencies, overall resolution, and the like. Such as foreground and background regions, may vary in gray scale, e.g., 160/128, 96/128, etc.; the spatial period may also be increased, for example using a graph with periods 2, 4, 6, 8, 10, 12, 15; the number of cycles may also be increased or decreased; the overall resolution may also be adjusted accordingly in accordance with the previous modifications.

The face test pattern is a face front pattern, which can be a real face or a cartoon face, and has a typical resolution of 65×65, and one real face pattern is shown in fig. 4. Referring to fig. 4, fig. 4 is a schematic diagram of a face pattern in an embodiment of a focusing adjustment method according to the present invention.

Further, in an embodiment, a plurality of the two-dimensional MTF test patterns and face patterns are displayed at a plurality of different positions on the first display panel.

In this embodiment, a plurality of two-dimensional MTF test patterns and face patterns are displayed at a plurality of different positions on the first display panel, and the specific positions and the specific number are set according to actual needs.

It should be noted that, here, only the schematic illustration of the focusing test image is provided, and in other embodiments, the focusing test image may include only one two-dimensional MTF test pattern and one face pattern, and be disposed at corresponding positions respectively. Namely, the number and distribution positions of the two-dimensional MTF test patterns and the face patterns are set according to actual needs.

Further, in an embodiment, four corners and centers of the screen body on the first display panel are provided with the two-dimensional MTF test pattern and the face pattern.

Referring to fig. 5, fig. 5 is a schematic diagram of a focus test image according to an embodiment of the present invention. As shown in fig. 5, two-dimensional MTF test patterns and face patterns are provided at each of four corner positions and a center position, that is, a focus test image includes a plurality of two-dimensional MTF test patterns and a plurality of face patterns.

Step S20, automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image;

in this embodiment, the passive autofocus technique based on the image is combined with the two-dimensional MTF test pattern in the first image, so as to achieve autofocus for the LMD. The description of the passive image-based autofocus techniques is as follows:

firstly quantitatively evaluating the definition degree of an image, namely calculating an image definition value by using an evaluation function, and then searching the next possible focusing position by using a one-dimensional search algorithm until the definition of the imaged image meets the requirement. Common evaluation functions can be divided into three types, one type is based on image gradients, and clear image gradient values are generally considered to be larger; one is based on the spectrum of the image, with sharp images being considered to contain more high frequency information; the last category is based on information theory, and the clear image entropy is larger.

The term "passive" in the term "passive image-based autofocus" refers to focusing not by means of an external sensor, but by means of the captured image itself, for example, some active focusing is equipped with a ranging sensor.

In order to find the correct focus position, the evaluation function needs to meet two basic requirements: unimodal and unbiased (as shown in fig. 6, fig. 6 is a graphical representation of the image sharpness evaluation function). Unimodal refers to the fact that the evaluation function value curve has only one peak; unbiased refers to the curve peak position, i.e. the focus position. Focusing is performed by searching for the peak position of the evaluation function, and if there is more than one peak value of the evaluation function, the algorithm may search for the wrong peak value to cause focusing failure; if there is only one peak of the evaluation function curve, but the position corresponding to the peak is not the focusing position, namely, there is a bias, focusing also fails. Thus, unimodal and unbiased can ensure that the search algorithm finds a unique peak of the evaluation function and corresponds to the focus position.

The evaluation function value is usually calculated by an LMD built-in circuit or an external PC according to the shot image, and the camera focusing ring is adjusted according to the change of the focusing function. That is, the focal position of the LMD is adjusted according to the focal evaluation function, for example, when the evaluation function is adjusted in the positive direction, the evaluation function is lowered, and then the LMD is adjusted in the negative direction until the focal evaluation function is lowered when the LMD is adjusted in any direction, and the LMD is the clear focal position.

When the focusing test image includes a plurality of two-dimensional MTF test patterns, the peak value of the evaluation function in the evaluation function of each two-dimensional MTF test pattern is integrated to determine the final focusing position.

Compared with the traditional one-dimensional MTF test pattern, the two-dimensional MTF test pattern used in the embodiment has the following characteristics: having a plurality of spatial frequencies of high, medium and low, rather than a fixed single frequency; the stripe pattern has both a transverse direction and a longitudinal direction. Thus, better unimodal and unbiased performance can be achieved also under two-dimensional MTF test patterns using image-based passive autofocus techniques.

Step S30, adjusting a focusing ring of the LMD according to the face pattern, so that the LMD is in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible.

In this embodiment, when the automatic focusing of the LMD is completed, only the focusing ring of the LMD needs to be slightly adjusted at this time, so that the LMD is in a slightly virtual focus state of the face pattern. The adjusting of the focusing ring of the LMD can be automatically performed based on preset adjusting parameters, and the adjusting of the focusing ring of the LMD can be performed manually based on operation actions of operators.

Further, in an embodiment, the step of adjusting the focus ring of the LMD includes:

In this embodiment, an operator triggers the adjustment operation through operation modes such as manual operation and sound control, after the execution main body of the embodiment receives the adjustment operation, the adjustment operation is responded to adjust the focusing ring of the LMD, and in the adjustment process, an image obtained by performing real-time image capturing on the face pattern in the focusing test image by the LMD is displayed on the second display panel, so that the operator can determine what state the LMD is in by observing the image displayed on the second display panel, thereby guiding the operator to adjust the LMD to a slight virtual focus state more quickly.

Referring to fig. 7a, fig. 7a is a schematic diagram of a face pattern obtained by capturing an image of an LMD in a clear focusing state according to an embodiment of the focusing adjustment method of the present invention. Referring to fig. 7b, fig. 7b is a schematic diagram of a face pattern obtained by capturing an image of an LMD in a less-virtual focus state according to an embodiment of the present invention. Referring to fig. 7c, fig. 7c is a schematic diagram of a face pattern obtained by capturing an image of an LMD in a slightly virtual focus state according to an embodiment of the present invention. Referring to fig. 7d, fig. 7d is a schematic diagram of a face pattern obtained by capturing an image of an LMD in an excessive virtual focus state according to an embodiment of the present invention. The face pattern obtained by taking an image of a typical LMD in a clear focusing state is shown in fig. 7a (LMD magnification is 3.09, and resolution of the face pattern after LMD imaging is 201×201); and (3) manually adjusting the LMD focusing ring, and watching the face pattern acquired by the LMD through the second display panel until the face pattern is as shown in fig. 7c (the LMD is in a slightly virtual focus state, the lattice points and the mole lines of the display panel are in an invisible state in the face pattern, and the face image on the face pattern is in a clear state).

As shown in fig. 7b, when the LMD is under the under-virtual focus, it is obvious that the pixel grid points and the mole patterns of the display panel exist in the face pattern obtained by the image capturing at this time.

As shown in fig. 7d, when the LMD is in excessive virtual focus, it is obvious that the pixels of the display panel in the face pattern obtained by the image capturing are not visible but the face is also blurred.

Among them, according to a large number of psycho-visual studies, humans have a high visual perception sensitivity to face patterns from the period of infants, which may be related to evolution and the later natural environment. Therefore, the face pattern obtained by LMD shooting is displayed in real time, and whether the focusing state of the LMD is clear focusing, under-virtual focusing, slight virtual focusing or excessive virtual focusing can be conveniently and directly judged from the second display panel.

When the focusing test image includes a plurality of face patterns, an operator performs comprehensive judgment on an image obtained by performing real-time image capturing on the plurality of face patterns according to the LMD displayed on the second display panel, so as to determine the focusing state of the LMD.

and adjusting the focusing ring of the LMD according to preset adjusting parameters.

In this embodiment, after the completion of the LMD auto-focusing can be predetermined by a calibration experiment, what adjustment needs to be performed on the focusing ring of the LMD to make the LMD be in a slight virtual focus state, and relevant adjustment parameters are stored. Subsequently, after the execution of step S20 is completed, the focusing ring of the LMD may be adjusted according to the preset adjustment parameter, so that the LMD is in a slight virtual focus state.

The focus adjustment of the LMD is a fundamental link of the display panel detection, however, the existing autofocus adjustment algorithm has the following problems when directly applied to the display panel detection. Firstly, focusing accuracy problems are the main application scene of the traditional automatic focusing algorithm is a real object in nature, the image of the traditional automatic focusing algorithm generally has good continuity in space and frequency domain, and when a shot object is a display panel with periodic discrete pixel points, the problems of complexity and the multiple peaks of a focusing evaluation function are more serious than those of the traditional automatic focusing algorithm, and at the moment, the focusing position obtained by the traditional automatic focusing algorithm can be wrong or obviously virtually focused; second, speed problems, conventional methods typically require multiple trial and error around the ideal focus to ensure focus accuracy; thirdly, a precise slight virtual focus state cannot be realized, the virtual focus degree is difficult to measure by a traditional image evaluation function, and the traditional method is easy to cause the virtual focus degree to be deficient or excessively deficient.

In this embodiment, a first image obtained by capturing, by an optical measurement device LMD, a focus test image displayed on a first display panel, where the focus test image includes a two-dimensional MTF test pattern and a face pattern; automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image; and adjusting the focusing ring of the LMD according to the face pattern, so that the LMD is in a slightly virtual focus state of the face pattern, wherein the slightly virtual focus state of the face pattern is that grid points and mole lines of the first display panel in the first image are invisible, and the face pattern is clearly visible. When AOI detection and DeMura are performed on the first display panel, the LMD needs to take an image of a screen body image on the first display panel in a slight virtual focus state in order to avoid or weaken moire. According to the embodiment, the LMD is automatically focused based on the two-dimensional MTF test pattern, and under the condition that the automatic focusing of the LMD is completed, the focusing ring of the LMD is further adjusted, so that the LMD can quickly reach a slight virtual focus state, and a screen image capable of accurately extracting the brightness of each pixel on the first display panel is quickly obtained.

Further, in an embodiment, after step S20, the method further includes:

detecting whether automatic focusing is correct or not; and if the automatic focusing is correct, executing the step of adjusting the focusing ring of the LMD.

In this embodiment, whether the autofocus is correct or not is detected, that is, whether the LMD is in a clear focusing state is detected, if yes, it is determined that the autofocus is correct, and step S30 is performed.

Further, in an embodiment, the step of detecting whether the autofocus is correct includes:

In this embodiment, a face pattern obtained by taking an image with the LMD in a clear focusing state may be preset, as shown in fig. 7a, as a standard face pattern. After step S20, the LMD, which is controlled to be automatically focused, again takes an image of the focus test image displayed on the first display panel, thereby acquiring a new first image.

The face pattern in the new first image and the preset LMD are in a clear focusing state to obtain a face pattern (namely a standard face pattern), if the similarity of the face pattern in the new first image and the preset LMD is larger than a preset threshold value, the face pattern obtained by shooting when the LMD is in the clear focusing state is indicated, and therefore automatic focusing is determined to be correct; otherwise, an autofocus error is determined.

Of course, the face pattern in the new first image may be displayed on the second display panel, and subjective judgment is performed on the face pattern in the new first image by an operator, if it is determined that the LMD is in the clear focusing state, the confirmation instruction is triggered, and when the execution subject in this embodiment receives the confirmation instruction, it is determined that the autofocus is correct. In contrast, if the operator triggers a negative instruction, when the execution body of the embodiment receives the negative instruction, an autofocus error is determined.

Further, in an embodiment, after the step of detecting whether the autofocus is correct, the method further includes:

In this embodiment, if an autofocus error is detected, the process returns to step S10, i.e., the autofocus process is performed again.

In a second aspect, an embodiment of the present invention further provides a focusing adjustment device.

In an embodiment, referring to fig. 8, fig. 8 is a schematic functional block diagram of a focusing adjustment device according to an embodiment of the invention. As shown in fig. 8, the focus adjustment apparatus includes:

an acquiring module 10, configured to acquire a first image obtained by capturing, by an optical measurement device LMD, a focus test image displayed on a first display panel, where the focus test image includes a two-dimensional MTF test pattern and a face pattern;

an auto-focus module 20 for auto-focusing the LMD according to the two-dimensional MTF test pattern in the first image;

the adjusting module 30 is configured to adjust the focus ring of the LMD, so that the LMD is in a slightly virtual focus state of the face pattern, where the slightly virtual focus state of the face pattern is that the grid points and the moire patterns of the first display panel in the first image are not visible, and the face pattern is clearly visible.

Further, in an embodiment, the focusing adjustment device further includes a detection module for:

detecting whether automatic focusing is correct or not;

Further, in an embodiment, the detection module is configured to:

if the automatic focusing is wrong, returning to the step of acquiring a first image obtained by taking the focusing test image displayed on the first display panel by the light measurement device LMD

Further, in an embodiment, the adjusting module 30 is configured to:

Further, in one embodiment, the two-dimensional MTF test pattern has a plurality of spatial frequencies, and the two-dimensional MTF test pattern is obtained by intersecting a transverse and a longitudinal stripe pattern having different spatial frequencies.

The function implementation of each module in the above-mentioned focusing adjustment device corresponds to each step in the above-mentioned focusing adjustment method embodiment, and the function and implementation process thereof are not described here in detail.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.

The foregoing embodiment numbers of the present invention are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments.

From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. ROM/RAM, magnetic disk, optical disk) as described above, comprising several instructions for causing a terminal device to perform the method according to the embodiments of the present invention.

The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.

Claims

1. A focus adjustment method, characterized in that the focus adjustment method comprises:

2. The focus adjustment method according to claim 1, further comprising, after the step of automatically focusing the LMD according to the two-dimensional MTF test pattern in the first image:

detecting whether automatic focusing is correct or not;

3. A focus adjustment method as defined in claim 2, wherein said step of detecting whether the autofocus is correct comprises:

4. A focus adjustment method as defined in claim 3, further comprising, after said step of detecting whether the autofocus is correct:

5. A focus adjustment method as defined in claim 1, wherein said step of adjusting the focus ring of the LMD comprises:

6. The focus adjustment method according to claim 1, wherein a plurality of the two-dimensional MTF test patterns and face patterns are displayed at a plurality of different positions on the first display panel.

7. The focus adjustment method according to claim 1, wherein the two-dimensional MTF test pattern and the face pattern are provided at four corners and a center of the screen body on the first display panel.

8. A focus adjustment method as claimed in any one of claims 1 to 7, characterized in that the two-dimensional MTF test pattern has a plurality of spatial frequencies, the two-dimensional MTF test pattern being obtained by intersecting a transverse and a longitudinal stripe pattern having different spatial frequencies.

9. A focus adjustment method as claimed in claim 8, characterized in that the two-dimensional MTF test is low frequency, medium frequency and high frequency in order from center to edge.

10. A focus adjustment device, characterized in that the focus adjustment device comprises: